ANALYSIS OF ALTERNATIVES Public Version

Legal name of applicant(s): Kemira Chemicals Oy

Submitted by: Kemira Chemicals Oy

Substance: Sodium dichromate

Use title: Use of sodium dichromate as an additive for suppressing parasitic reactions and oxygen evolution, pH buffering and cathode corrosion protection in the electrolytic manufacture of sodium chlorate with or without subsequent production of chlorine dioxide or sodium chlorite.

Use number: 1 Disclaimer

This report has been prepared by Risk & Policy Analysts Ltd, with reasonable skill, care and diligence under a contract to the client and in accordance with the terms and provisions of the contract. Risk & Policy Analysis Ltd will accept no responsibility towards the client and third parties in respect of any matters outside the scope of the contract. This report has been prepared for the client and we accept no liability for any loss or damage arising out of the provision of the report to third parties. Any such party relies on the report at their own risk.

Note

This public version of the Analysis of Alternatives includes some redacted text. The letters indicated within each piece of redacted text correspond to the type of justification for confidentiality claims which is included as an Annex (Section 7) in the complete version of the document. Table of contents

1 Summary...... 1 1.1 Use applied for...... 1 1.2 Potential alternatives for sodium dichromate...... 1 1.3 Suitability of potential alternatives to sodium dichromate...... 4 1.4 Feasibility and availability of potential alternatives for sodium dichromate ...... 6 1.5 Actions needed to improve the suitability and availability of potential alternatives...... 10

2 Analysis of substance function ...... 13 2.1 The chlorate process...... 13 2.2 Conditions of use and technical feasibility criteria...... 20 2.3 Summary of functionality of sodium dichromate in the “Applied for Use” ...... 27

3 Annual tonnage...... 29 3.1 Tonnage band ...... 29 3.2 Trends in the consumption of sodium dichromate ...... 30 3.3 Form and usage of sodium dichromate...... 30

4 Identification of possible alternatives...... 31 4.1 List of possible alternatives...... 31 4.2 Description of efforts made to identify possible alternatives ...... 31 4.3 Screening of identified alternatives...... 61

5 Suitability and availability of possible alternatives...... 83 5.1 Introduction ...... 83 5.2 Chromium(III) chloride...... 83 5.3 Sodium molybdate...... 93 5.4 Molybdenum-based coatings ...... 103 5.5 Two-compartment electrolytic systems ...... 109

6 Overall conclusions on suitability and availability of possible alternatives...... 117 6.1 Technical feasibility of shortlisted alternatives ...... 117 6.2 Economic feasibility of shortlisted alternatives...... 119 6.3 Reduction of risks from the use of shortlisted alternatives...... 120 6.4 Availability of shortlisted alternatives ...... 121 6.5 Overall conclusion...... 122 7 Annex – Justifications for confidentiality claims...... 125

8 Appendix 1 – Information sources...... 127

9 Appendix 2 – Comparative hazard and risk characterisation of alternatives...... 131 9.1 Background ...... 131 9.2 Reference values for sodium dichromate and alternative substances...... 131 9.3 Exposure Assessment...... 154 9.4 Comparative risk characterisation...... 159 9.5 References for this Appendix...... 160

10 Appendix 3 – Economic feasibility ...... 163 10.1 Economic feasibility of sodium molybdate...... 163 10.2 Economic feasibility of molybdenum-based coatings ...... 172 10.3 Economic feasibility of two-compartment electrolytic systems...... 177

1 Summary

1.1 Use applied for

This Analysis of Alternatives (AoA) is part of an Application for the Authorisation (AfA) for the continued use of sodium dichromate (CAS No. 7789-12-0 & 10588-01-9; EINECS No. 234-190-3, hereafter referred to as “SD”) by the applicant, Kemira Chemicals Oy (hereafter referred to as Kemira), in the sodium chlorate (NaClO3) manufacturing process, where it acts as a crucial additive to the process. Generation of sodium chlorate is based on the electrolysis of sodium chloride (NaCl), at a controlled pH range, where the chloride is converted into sodium chlorate while hydrogen evolves as a co-product. SD acts to increase the current efficiency of the conversion process by suppressing unwanted (parasitic cathodic) reactions and thus reducing the use of electrical energy, and acts as a pH buffer to ensure optimal process conditions are maintained. It also has a crucial role in limiting the amount of oxygen generated during the process, the presence of oxygen poses a serious hazard because it will forms explosive atmospheres in the presence of hydrogen.

Kemira is using <#B# tonnes of SD out of a total consumption of <40 tonnes consumed in this use by EU-based manufacturers of sodium chlorate. This overall volume represents less than 1% of the entire amount of SD used each year in the EU.

This AoA has been prepared by an independent third party working on behalf of Kemira and a further six EU-based users of SD who collectively formed the Sodium Dichromate Authorisation Consortium (hereafter referred to as SDAC). While there is notable overlap in the information presented and the argumentation made in the AoA documents of all seven applicants, each AoA document, including the present one, is tailored to the specific applicant and describes the specific situation for Kemira. It must be noted that each of the company-specific AoA documents may include information which is available only to the applicant and which (a) is confidential, and (b) does not appear in the AoA documents of the remaining SDAC applicants. 1.2 Potential alternatives for sodium dichromate

This AoA details an extensive search of literature carried out by the independent third party. In addition, consultation with all seven SDAC members regarding their extensive R&D efforts has been used in conjunction with the publicly available information to ensure all relevant alternatives have been considered. In total, ten alternative substances and technologies were identified and evaluated, and these are summarised in Table 1-1.

Table 1-1: Master list of identified potential alternatives for SD in sodium chlorate manufacture

No Potential alternative substances 1 Chromium (III) chloride 2 Sodium molybdate 3 Rare Earth Metal (III) salts No Potential alternative cathode coatings 4 Molybdenum-based cathode coatings 5 Ruthenium-based cathode coatings 6 Zirconium- based cathode coatings

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 1 Table 1-1: Master list of identified potential alternatives for SD in sodium chlorate manufacture No Potential alternative cathode materials 7 Ruthenium alloy cathodes No Potential alternative electrolytic processes 8 Two-compartment electrolytic systems 9 Two-compartment electrolytic cells with oxygen-consuming gas diffusion electrodes 10 Polymeric cathode film coatings

The screening of the identified alternatives included the following steps:

 Commercialisation status: this step looked into whether each of the alternatives is commercially available. If yes, the question was how quickly could it be implemented on an industrial scale by the applicant; if no, the analysis looked into how quickly it mightbecome available on an industrial scale. This step eliminated Alternatives 9 and 10 as they are currently very far away from any foreseeable commercialisation scenario  Suitability for SD replacement: this step looked into the fundamental criterion of whether each identified alternative is able to eliminate the handling of and exposure of workers to SD. Under the current state of knowledge, some of the identified alternatives (Alternatives 2, 5 and 7) cannot perform to an acceptable level unless SD is present in the electrolyte (the sodium chlorate cell, as is described in detail in Section 4.3.3). Additionally it should be noted that the use of Alternative 1 results in the formation of SD in the electrolyte (although, compared to the use of SD, it eliminates worker exposure arising from the handling of SD during the dosing task, the first step in the use of SD to produce sodium chromate)  Technical feasibility criteria comparison: this step utilised a list of seven criteria to compare the technical feasibility of the identified alternatives. The criteria are:

 Formation of protective film permeable to H2 but impermeable to hypochlorite  Control of oxygen formation  Cathode protection  pH buffering  Current efficiency and overall energy consumption  Solubility in the electrolyte (for alternative substances only)  Lack of impurities in the sodium chlorate product

This screening identified specific technical shortcomings for some of the potential alternatives, e.g. poor energy efficiency (Alternative 2), generation of excessive amounts of O2 (Alternative 2), very low solubility (Alternative 3), poor pH buffering (Alternatives 2, 4, 5, 7) and poor reaction selectivity (Alternative 7)  Engineering and economic feasibility: this step looked at the practical (incl. engineering) steps required for each of the identified alternatives and the key complexities of these practical steps. A series of alternatives were found to be practically impossible to implement due to inherent and, to the applicant’s best knowledge, insurmountable problems, e.g. poor solubility (Alternative 3), unavailability of suitable cathodes (Alternatives 5 and 6), and lack of industrial scale proof of concept and experience (Alternatives 3, 5, 6 and 7).

An overview of results is given in Table 1-2. The table identifies the shortlisted potential alternatives which form the core of the assessment in Section 5 of this AoA:

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 2  Alternative 1 (substance): Chromium (III) chloride for completeness, given the lack of suitability in eliminating Cr(VI) exposure  Alternative 2 (substance): Sodium molybdate  Alternative 4 (technology): Molybdenum-based cathode coatings, and  Alternative 8 (technology): Two-compartment electrolytic systems.

Table 1-2: Summary of the screening of identified potential alternatives for SD in the manufacture of sodium chlorate Compared Suitability to SD in Engineering Commerciali- as SD terms of and Shortlisted for Alternative sation status replacement technical economic further analysis? (exposure) feasibility feasibility criteria No Potential alternative substances 1 Chromium (III) Not Unsuitable Uncertain Uncertain Yes – but unsuitable compounds immediately as it only due to lack feasibility for reducing worker available and leads to a of and cost exposure most likely very small knowledge while 3rd unavailable at reduction to of party sunset date exposure conditions patent (ca. 20% for and application some parameters pending workers) of use 2 Sodium Unproven on Low SD Worse Not Yes molybdate the industrial levels may available on scale; uncertain be required industrial future scale 3 Rare Earth Metal Impossible to Acceptable Worse Impossible No (III) salts use No Potential alternative cathodic coatings 4 Molybdenum- Unproven on SD addition Probably Infeasible Yes based cathode the industrial may be worse; and coatings scale; uncertain required better unavailable future claimed on energy industrial efficiency scale 5 Ruthenium- Unproven on SD addition Worse Impossible No based cathode the industrial required coatings scale; uncertain future 6 Zirconium- based Unproven on SD addition Uncertain Impossible No cathode coatings the industrial may be scale; uncertain required future

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 3 Table 1-2: Summary of the screening of identified potential alternatives for SD in the manufacture of sodium chlorate Compared Suitability to SD in Engineering Commerciali- as SD terms of and Shortlisted for Alternative sation status replacement technical economic further analysis? (exposure) feasibility feasibility criteria No Potential alternative cathode materials 7 Ruthenium alloy Unproven on SD addition Worse Impossible No cathodes the industrial required scale; uncertain future No Potential alternative electrolytic processes 8 Two- Not used for Acceptable Uncertain, Feasible Yes compartment chlorate likely to be but very electrolytic production worse than costly systems SD

1.3 Suitability of potential alternatives to sodium dichromate

1.3.1 Risks to human health and the environment from direct substitution

A detailed comparative risk assessment for environmental and human health effects has been undertaken to assess the suitability of chromium (III) compounds and sodium molybdate which could in theory act as ‘drop-in’ replacements for SD. This assessment, included in this AoA as Appendix 2 (Section 8), has also looked into the risks to human health and the environment from sodium phosphates. These would need to be added to the electrolyte in the absence of SD if sodium molybdate (or molybdenum-coated cathodes) is used to act as a pH buffer.

For the comparative assessment of human health and environmental risks of SD and the potential alternative substances, the following approach was used:

 Available reference values (DNELs, PNECs) were analysed  Where no reference values were available, which were derived by similar methodologies to allow for a comparison, tentative reference values were derived  An exposure scenario was established similar to the actual exposure scenario for SD  Exposure modelling input data were compiled for all alternative substances and SD  Exposure levels and risk characterisation ratios for the environment were calculated using ECETOC TRA  Exposure levels for workers were modelled using ART (Advanced REACH Tool).

Comparison of hazard data (classifications) reveals that none of the alternatives investigated are CMR substances and that none of the alternatives have been classified for environmental hazards. Moreover, the tentative risk characterisation shows that the alternative substances (chromium(III) chloride, sodium molybdate and sodium phosphates) have lower RCRs for both human health endpoints (workers) and the environment; therefore, the alternative substances assessed in detail are beneficial with regard to human health considerations and fulfil the REACH Authorisation requirement of leading to a reduction in overall risks to human health and the environment compared to the Annex XIV substance SD, based on the assumptions used in Appendix 2.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 4 However, the use of chromium(III) chloride does not avoid the presence of Cr(VI) species in the electrolyte. Use of a Cr(III) compound instead of SD would eliminate exposure during Task 1 (feeding liquid SD solution into the process, i.e. dosing, see Table 5-7). All other Tasks, in terms of worker exposure to Cr(VI) species, would remain unchanged. Importantly, any worker who is involved in dosing SD (a generally infrequent task), is also involved in one or more other Tasks which may result in exposure to Cr(VI). As a result, the use of a Cr(III) compound in the place of SD would only eliminate a very small percentage (ca. 20%) of aggregate exposure of some workers (see Section 5.2.4) but the exposure of other workers would not be affected.

Therefore, despite chromium(III) chloride resulting in a reduction in risk, this alternative cannot be considered suitable as its use only marginally reduces exposure to the Cr(VI) anion that confers to SD its SVHC (CMR) properties.

For the two alternative technologies, molybdenum-coated cathodes and two-compartment electrolytic cells, a direct comparison of risks against SD is not possible. In the case of molybdenum- coated cathodes, it is assumed that no additives would be required apart from a sodium phosphate buffer. For two-compartment electrolytic cells, no additives are assumed to be added. It is therefore assumed that the risks from the use of SD would be eliminated and new hazards would not be introduced to the operation of the cells (although, the extent to which molybdenum-coated cathodes would control the evolution of oxygen is uncertain), hence, both alternative technologies are assumed to reduce the overall risk to human health and the environment.

1.3.2 Environmental externalities from changes in energy consumption

Electricity is the most significant component of the production cost of sodium chlorate. With the exception of chromium(III) chloride that largely acts in the electrolyte as SD, the use of any of the other three alternatives would result in notable increases in energy consumption. Increased energy consumption is expected for sodium molybdate and two-compartment cells, which would result in increased indirect emissions of greenhouse gases due to the need to generate additional electricity.

In contrast, if claims made in the patent literature were to be confirmed at the industrial scale, the use of molybdenum-coated electrodes could theoretically result in a modest reduction in indirect greenhouse gas emissions due to increased energy efficiency. However, such claims are impossible to verify without trialling this alternative on an industrial scale over a test period much longer than that documented in the relevant patent literature. Moreover, the concomitant use of phosphate buffers would increase oxygen generation and reduce the efficiency and yield of the process. Given these uncertainties, a calculation of environmental externalities resulting from change(s) in energy consumption is not provided for this alternative.

A summary of the calculated changes in energy consumption and associated changes to the release of greenhouse gases (CO2) is presented in Table 1-3.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 5 Table 1-3: Environmental externalities from changes in energy consumption under the shortlisted alternatives for Kemira '''''''''#G#''''''''' '''''''''''''''''''' '''''''''''''''''''''''''' '''''' '''''''''''''''' ''' ''''''' Alternative ''''''''''''' '''''''''''''''''''''' '''''''''''''''''''''''' '''''''''''' '''''''''''''''''' '''''''''''''''''' '''' ''''' ''''''''''''''''' ''''''''''''''''''' '''' ''''' Chromium(III) ''''''' ''''''''''''''' ''''''' '''''''''''''''''' '''''''' ''''''''''''''''' '''''''' ''''''''''''''' chloride Sodium ''''''''''''''''' '''''' '''''''''''''' ''''''''''''' ''''''''''''''' '''''''''' ''' ''''''' '''''''''''' ''''''''''' ''''''''''''''''' molybdate ''''''''''' Molybdenum- '''''''' '''''''''''''''''''' ''''''' '''' ''''''''''''''''''''''' ''''''''' ''''''''''''''''' '''' ''''''''''''' ''''''''''''''''''''''''' based coatings Two- compartment '''''''''''''''' '''''' '''''''''' ''''''''''''' ''''''''''''''''' '''''''''''' ''' ''''''' '''''''''''''' ''''''''''' '''''''''''''''''' electrolytic '''''''''' systems Important note: these figures are based on simple assumptions on energy consumption increases (changes in cathode potential) and do not take into account effects that may exacerbate energy consumption such as the addition of phosphates. For instance, the increased oxygen release due to the phosphate addition which results in anodic losses is not included. This is particularly important for Mo-based coatings which may in reality not result in energy savings (certainly not of the magnitude implied in published lab-based research) 1.4 Feasibility and availability of potential alternatives for sodium dichromate

1.4.1 Assessment of technical feasibility

The potentially feasible alternatives have all been proposed in academic literature and in patents as potential alternatives to the use of SD as an additive or, in the case of molybdenum-based coatings and two-compartment cells, as an alternative way of producing sodium chlorate. Despite their proposed use, only the chromium(III) chloride alternative is believed to have been implemented on a commercial scale use by the holder of the relevant patent application. The applicant has experience of the technical feasibility of these potential alternatives and this AoA relies substantially on the descriptions and claims made in the relevant published research, some of which has been performed by direct competitors. The conclusions of the assessment of technical feasibility are summarised in Table 1-4.

Table 1-4: Overview of technical feasibility of shortlisted alternatives for Kemira Conclusion on Alternative Technical advantages Technical disadvantages technical feasibility Chromium(III) Once in the electrolyte, it Details unknown to the applicant. Does Potentially chloride is oxidised to Cr(VI) and not eliminate the greatest part of current feasible, but may behave as if SD had worker exposure to Cr(VI) applicant has been dosed in no access to technology

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 6 Table 1-4: Overview of technical feasibility of shortlisted alternatives for Kemira Conclusion on Alternative Technical advantages Technical disadvantages technical feasibility Sodium - Sufficiently soluble - Unstable protective film on the Infeasible molybdate - Relatively simple, cathode ‘drop-in- substitute - Poor pH buffer requiring the addition of phosphates which interfere with and adversely affect the stability and longevity of the anode and may increase oxygen evolution - High evolution of oxygen gas potentially leading to explosive mixtures with hydrogen - Worse current efficiency and electricity consumption than SD - Unproven on an industrial scale Molybdenum- - Patent literature - Poor pH buffer requiring the addition Infeasible based coatings claims a lower of phosphates which interfere with electricity and adversely affect the stability and consumption than SD longevity of the anode and may increase oxygen evolution - Potential issues with high evolution of oxygen gas - Would still require Cr(VI) - Unproven on an industrial scale, hence great uncertainty over control of parasitic reactions and cathode lifetime - Necessary cathodes not presently available Two- - Solubility, cathodic - Worse current efficiency and Infeasible compartment film formation and electricity consumption than SD electrolytic oxygen evolution - Unproven on an industrial scale systems issues inherently specifically for chlorate manufacture resolved - Would require complete plant rebuild - pH control required but can be addressed without the use of added buffers

1.4.2 Assessment of economic feasibility

From the assessment of technical feasibility, it is clear that the alternatives other than the Chromium(III) chloride are not technically feasible. However, for the sake of completeness, the potential economic feasibility of the shortlisted alternatives has been considered in Appendix 3. These are based on early patent trials, and it has been assumed that the data presented in these is reliable:

 The initial capital investment required for the conversion from SD to an alternative substance or technology, which would need to be recouped through increases in the end price to customers of the sodium chlorate

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 7  Undertaking the capital investment in the unproven technologies would also result in significant downtime and the likely loss of customers for the sodium chlorate  The change in operating costs, primarily represented by the cost of energy which is by far the largest component of production costs in the sodium chlorate industry. Any increase in the consumption and therefore the cost of energy would have a significant impact on on-going operating costs and also lead to potentially significant increases in end product prices to customers in order to retain profitability; this would impact on the competitiveness of the individual companies vis a vis non-EU suppliers of sodium chlorate.

Cr(III) may potentially be an economically feasible alternative, as it is straightforward to substitute it directly into the current process; however, the cost is uncertain as the applicant is not familiar with the parameters and conditions of the relevant technology. The remaining three unproven alternatives would require substantial investment costs (particularly the two-compartment electrolytic systems, which require a new plant to be built), which would have to be recouped through potentially very large increases in the price of sodium chlorate. As noted above, on-going operating costs are dominated by the cost of energy. For sodium molybdate and two-compartment electrolytic systems, the energy consumption of the process would show a notable increase, which would result in significant increases in CO2 and other atmospheric emissions, as well as the need to further increase the price of the end sodium chlorate to customers. At a company level, the combined effect of one of the companies not gaining authorisation would be a significant deterioration in profit margins and the likely inability to remain competitive within the EU market. For molybdate-based coating systems, the information available in the patent literature would suggest a reduction in energy consumption, however, it is uncertain whether this would materialise on the industrial scale in the presence of phosphates, which would result in anodic losses and increased maintenance costs due to the impaired longevity of the anodes. Even if it were to be assumed that this unproven technology could deliver a reduction in operating costs, the very high investment costs and downtime period required to shift to new plant would render this alternative economically infeasible.

1.4.3 Assessment of availability

Table 1-5 summarises the findings of this AoA with regard to the availability of the shortlisted alternatives for SD. None of the shortlisted alternatives are currently available, because either they have not been proven on the industrial scale, and/or access to the (pending) patents by the sunset date is not known and therefore cannot be assessed.

Table 1-5: Overview of availability of shortlisted alternatives Access to required Conclusion on Alternative Quantity availability Quality availability technology (rights) availability

Chromium(III) - CrCl3 not REACH - No issue - Access to Unavailable at chloride registered identified patented present and - Quantity needed technology probably is less than 10 t/y required; license unavailable at terms not known sunset date as awaiting patent - Patent filed but not yet granted - Access to technology would

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 8 Table 1-5: Overview of availability of shortlisted alternatives Access to required Conclusion on Alternative Quantity availability Quality availability technology (rights) availability not be possible by the sunset date - Kemira is familiar with recycling Cr(III) into the electrolyte Sodium - Sodium - No issue - Existing (known) Unavailable molybdate molybdate is identified but patent rights held REACH registered technology is by third parties - Quantity needed unproven on the is less than 10 t/y industrial scale Molybdenum- - Raw materials - Unknown at - Existing (known) Unavailable based coatings available on the present, as patent rights held market technology is not by third parties - Required proven on the cathodes not industrial scale currently available Two- - Chlor-alkali - Unknown at - Technology is not Unavailable compartment technology present, as proven for electrolytic widely available technology is not chlorate systems on market proven for manufacture on chlorate the industrial manufacture scale

1.4.4 Summary of feasibility and availability of shortlisted alternatives

The findings of the analysis on the technical and economic feasibility and availability of alternatives are briefly summarised in Table 1-6 below.

Table 1-6: Overall conclusions on suitability and availability of shortlisted alternatives for Kemira Technical Economic Reduction Alternative Availability Conclusion Feasibility Feasibility in risk Does not remove all exposure to Chromium (VI), Chromium(III) HH:  (-) ?  uncertain availability and chloride ENV: - of uncertain economic feasibility Not CMR therefore  suitable, increased (unproven, pH  environmental Sodium buffering, HH:  (high energy  externalities. molybdate energy ENV:  cost) consumption, Technically and economically infeasible and O2 evolution) unavailable

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 9 Table 1-6: Overall conclusions on suitability and availability of shortlisted alternatives for Kemira Technical Economic Reduction Alternative Availability Conclusion Feasibility Feasibility in risk  (unproven, pH  buffering, (high plant Not CMR therefore Molybdenum- uncertain conversion HH:  suitable, technically and  based coatings energy cost, ENV: ? economically infeasible and consumption, uncertain unavailable possible O2 profitability) issues)  Not CMR therefore (very high suitable, increased Two-  plant environmental compartment (unproven, conversion HH:   externalities. electrolytic high energy cost, high ENV:  Technically and systems use) energy costs, poor economically infeasible and profitability) unavailable : better than SD; : worse than SD; - : no change compared to SD Parentheses indicate degree of uncertainty

1.5 Actions needed to improve the suitability and availability of potential alternatives

The actions and timescale that would theoretically be required before the shortlisted available became feasible and suitable are presented in Table 1-7.

The alternatives that have been identified have already been the subject of significant R&D efforts by members of the SDAC and by other entities. Despite this, the identified shortcomings are yet to be overcome. Their transition from the laboratory to the industrial scale has not been possible nor can the timeframe for such a transition be predicted with any degree of accuracy.

The use of chromium(III) chloride in the production of sodium chlorate is patented by a competitor; this alternative might become available to the applicant in the future after negotiation with the patent (application) holder, but the terms of any licence are uncertain. However, this alternative is not considered suitable due to (a) the continued presence of Cr(VI) species in the electrolyte and (b) the very small reduction in worker inhalation exposure that could be achieved in comparison to the use of SD.

The use of two-compartment electrolytic systems would currently result in unacceptable increases in electrical consumption and would not be economically feasible due to the need to construct entirely new production facilities. Given the impending increases in the cost of electricity in the EU in the long term (EC, 2013), energy prices would need to decrease significantly for investment in such large-scale projects to become attractive.

The most promising technology might be implied to be molybdenum-based coatings, as these have been suggested to result in significantly reduced energy consumption. However, current indications suggest that this technology may still result in increased oxygen levels and compromise process safety unless small amounts of SD are used. In addition, the expected lifetime of these coated cathodes has not been evaluated. In particular, the scientific community needs to undertake further

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 10 R&D on this technology and then demonstrate it on a commercially relevant scale in a pilot plant facility before any suggestion of economic feasibility can be confirmed. The technology that has been described in the known patents is protected until 2028, and it is unlikely that further R&D will yield results before then.

In conclusion, the Authorisation is applied so that Kemira can continue to produce sodium chlorate until a technically and economically feasible alternative is developed. The benefits from the continued use of SD under closely controlled conditions and with minimisation of worker exposure significantly outweigh the risks to human health posed by the use of SD in the applicant’s plant, as shown in the accompanying Socio-economic Assessment (SEA) document. It is not realistic for Kemira to aim towards the adoption of any one of the known, published technologies as their feasibility is uncertain and the time required for their industrial scale-up is unclear.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 11 Table 1-7: Actions and timescale required for improving the suitability and availability of shortlisted alternatives Potential timeframe for the Actions for improving of Actions for improving of Alternative Actions for improving of feasibility alternative becoming feasible suitability availability and suitable Time required for granting of patent and negotiations by Kemira for securing access Uncertain what actions would be rights to patented technology Cannot improve; the alternative Need to obtain access to required, as the applicant has no on commercially and Chromium(III) chloride will always result in largely patented technology once access to the particulars of the economically acceptable terms. similar Cr(VI) exposure as SD patent has been granted technology However, alternative is not a long-term solution due to presence of Cr(VI) in the electrolyte Already suitable for CMR effects; Further R&D is required before energy Technology needs to be technical improvements required Sodium molybdate use, pH buffering and O issues are developed further to become Uncertain, but long 2 for control of energy addressed commercially viable consumption increases Further R&D is required before pH Technology needs to be buffering and possible O issues are Already suitable for CMR effects; developed further and reach Molybdenum-based 2 addressed and reduction of energy reduction in energy consumption commercialisation. Uncertain, but long coatings consumption is proven under not certain, needs to be verified Mo-coated cathodes need to industrial scale operating conditions become available on the market Technology already available, but for use in chlorate Chlor-alkali technology is known but Already suitable for CMR effects; manufacture it is unlikely to Uncertain, but long Two-compartment needs to be proven on an industrial increased environmental improve due to very high initial (will probably never become an electrolytic systems scale for chlorate manufacture externalities are difficult to avoid costs and increasingly attractive solution) unappealing electricity costs in the EU

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 12 2 Analysis of substance function

2.1 The chlorate process

2.1.1 Description and electrochemical reactions

The “Applied for Use” is the use of SD as an additive in the manufacture of sodium chlorate from sodium chloride by electrolysis, with no SD presence in. In short, chlorate is produced in undivided cells with oxidation of chloride to chlorine on the anodes, and hydrogen evolution on the cathodes made of steel or titanium (Cornell, 2002). The manufacture of sodium chlorate in the EU is the same as anywhere else in the world and involves the following steps (note that the chlorate process is detailed in the IPPC BREF - Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals; photographs showing some tasks involved are available in the Chemical Safety Report):

 Brine preparation: saturated sodium chloride brine needs to be used and the electrolytic process requires high purity brine. Therefore, after the preparation of the brine by dissolving 2+ 2+ 2- the solid sodium chloride salt in hot water, impurities in the salt (e.g. Ca , Mg , SO4 ) are removed through precipitation (using NaOH, Na2CO3 and CaCl2) and filtration (IPPC, 2007)

 Electrolysis: the brine is transferred to an electrolysis cell along with SD as an additive (and potentially hydrochloric acid or chlorine for pH adjustment). As will be discussed in more detail below, SD is used to ensure suitable conditions for promoting sodium chlorate formation and avoiding side reactions during electrolysis.

The electrolysis of sodium chloride into sodium chlorate takes place in a controlled range of temperatures, 60-90 °C, and a pH of 6.0-6.5 (IPPC, 2007). The anodes are typically made of titanium covered with a noble metal coating and cathodes are generally made of steel (IPPC, 2007). Cathode materials in the first years of chlorate manufacture were copper, nickel and platinum. Today, apart from steel, some plants use titanium or a Ti-0.2% Pd alloy (Cornell, 2002).

The production of chlorate relies on the electrolysis of chloride (eqs. 1-4), also producing hydrogen as a co-product (eq. 5) (Mendiratta & Duncan, 2003). Chlorine, due to the pH conditions, remains in solution forming hypochlorous acid and hypochlorite ions. The liquor (the solution from cells) is continuously circulated between the cells and the reaction tanks (IPPC, 2007). The overall reaction can be summarised by equation 6 (eq. 6):

- - 2Cl ⇄ Cl2 + 2e (1)

Cl2 +H2O ⇄ HOCl + HCl (2) - - - + 2HOCl + ClO ⇄ ClO3 + 2Cl + 2H (3) - - - + - 6ClO + 3H2O ⇄ 2ClO3 + 4Cl + 1.5 O2 + 6H + 6e (4) + - - - 2H + 2e ⇄ H2 (this equation is often presented as 2H2O + 2e ⇄ H2 + 2OH ) (5)

NaCl + 3H2O ⇄ NaClO3 + 3H2 (6)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 13 The production of protons (eqs. 3 and 4) and their conversion into hydrogen (eq. 5) indicate that the control of electrolyte pH is a key variable in the process. A further issue is the evolution of oxygen during the process by another competing electrochemical reaction (eq. 7).

+ - 2H2O ⇄ O2 + 4H + 4e (7) Inhibition of this side-reaction is an important part of the process, both for current efficiency and safety reasons due to the explosive atmospheres potentially formed in the presence of hydrogen. The anodic selectivity can be disturbed by certain compounds in the electrolyte, thus further increasing oxygen formation (Kus, 2000).

 Crystallisation and drying: sodium chlorate is recovered from the liquors in a crystallisation unit by first concentrating the liquor using vacuum followed by cooling to precipitate the crystals of sodium chlorate. These are then separated from the liquor by centrifugal filtration. The crystals are dried, commonly using fluidised bed dryers using heated air (IPPC, 2007).

This process is illustrated in Figure 2-1.

Figure 2-1: The Sodium Chlorate Process Showing Outputs and Emissions, adapted from Tilak & Chen (1999), Mendiratta & Duncan (2003) and IPPC (2007)

Two key characteristics of the process must be noted:

 Use of closed loop systems and recycling of liquors: a predominantly closed system is used. Where this is not possible, a high degree of recycling of chlorate and liquors (containing SD) is maintained to minimise the output of Cr(VI) in the chlorate and the release of Cr(VI) to the aquatic environment. Efficient dewatering and washing of the chlorate crystals also enables a low output of chromium with the product. The process has been highly optimised over the course of its operation (Tilak & Chen, 1999) and produces large amounts of chlorate in comparison to the amount of SD consumed (IPPC, 2007)).

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 14  High hydrogen utilisation to improve the economics of the process: besides the main product, a co-product of approximately 57 kg of hydrogen1 is produced per tonne of chlorate as indicated in the relevant BREF document (IPPC, 2007). This by-product is also collected and, for overall energy and economic efficiency, it is important to utilise hydrogen to a high degree. This depends on local conditions and the possibility of finding an outlet for using the hydrogen, either as a source of energy or as a raw material for chemical reactions. The possibility of utilising hydrogen outside of the sodium chlorate plant substantially reduces the amount of the fossil fuels required either for the production of the equivalent amount of energy or hydrogen used in chemical synthesis or both. This improves the overall economics of the chlorate production plant.

Typical conditions for the process are shown in Table 2-1, as described in literature. The values shown are approximate and other concentrations of sodium chloride and final chlorate can be used. The example uses a platinum-iridium anode but other electrode materials may also be used. Typically, these are ruthenium oxide, platinum-iridium coated titanium based anodes (Tilak & Chen, 1999).

Table 2-1: Example operating conditions for a chlorate cell (steel cathode and Pt/Ir anode) Parameter Valuea Valueb Unit Current density 2-3 1-3 kA/m2 Current efficiency 94 - % Average cell voltage 3-3.5 2.6-3.5 V Electrical energy requirement 5,700 5,000-6,000 kWh/t Process temperature 80 - °C Electrolyte Composition Valuea Unit NaCl 150 g/L

Na2Cr2O7 2-5 g/L NaOCl 3-5 g/L

NaClO3 500-600* g/L Source: a Mendiratta & Duncan (2003); b IPPC (2007) * based on Cornell (2002)

With particular regard to energy requirements, electricity consumption is typically in the range of 5000 – 6000 kWh/t, depending on the current density (IPPC, 2007).

1 Theoretical production 56.9 kg of hydrogen per 1000 kg of sodium chlorate according to: NaCl + 3H2O  NaClO3 + 3H2.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 15 2.1.2 The role of sodium dichromate

Overview

SD plays four interlinked roles in the sodium chlorate production process:

1. It acts as a pH buffer

2. It suppresses the production of oxygen, thus preventing the creation of explosive mixtures with hydrogen

3. It passivates the steel cathodes, thus protecting them from corrosion

4. It increases energy efficiency and the overall efficiency of the chlorate process by suppressing certain parasitic reactions at the cathode.

The suppression of cathode reactions appears to be by far the most critical task for SD and is explained under Point 4 below.

Function 1: pH buffering

SD acts as a buffer, i.e. a weak acid or base which maintains the acidity of a solution at a chosen value that resists changes to the pH from the addition of another acid or base. The dichromate anion has the ability to react with both hydrogen cations and hydroxide anions in accordance to eqs. 8 and 9.

2- + Cr2O7 + 2H ⇄ H2Cr2O7 ⇄ H2CrO4 + CrO3 (8) 2- - - Cr2O7 + 2OH ⇄ 2CrO4 + H2O (9)

Speciation of SD varies with pH in a water solution, as shown in the above equations and in Figure 2-2. The species will be the same in the chlorate electrolyte but the pH scale might differ slightly. As can be seen, in the - pH range relevant to chlorate production (pH 6.0-6.5, as explained in Section 2.2.4), all three species (HCrO4 , -2 -2 -2 Cr2O7 and CrO4 ) will be present. At alkaline conditions the chromate ion CrO4 with sodium as counter ion (Na2CrO4) will dominate, whereas in the acidic pH range the sodium dichromate (SD) Na2Cr2O7 and or NaHCrO4 will dominate. Therefore, when reference is made in this AoA to the “presence of SD in the electrolyte”, it is meant that Cr(VI) may be found in a variety of forms which, in co-existence, deliver the required functionality at an concentration equivalent to 3 g SD per litre of electrolyte

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 16 Figure 2-2: The distribution of Cr(VI) species in aqueous solution as a function of pH. The lines represent -2 - -2 H2CrO4 (…), Cr2O7 (- - -), HCrO4 (_.._), and CrO4 (̶ ̶ ̶). A Cr(VI) concentration of 0.05 M applies Source: Ramsay et al (2001)

According to Tilak & Chen (1999), to maximise the electrolytic cell efficiency and ensure the safety of the plant, the pH must be controlled within a narrow range, 6.0-6.5, as shown in the BREF Document referred to above. Controlling the pH can be beneficial because at low pH the evolution of oxygen decreases (eq. 7) but that of Cl2 increases (eq. 1); at high pH, the opposite occurs. Moreover, maintaining the pH of the cell solution at the given range helps in avoiding the corrosion of the anode due to oxygen evolution.

Function 2: Suppression of oxygen production

As shown above, at low pH the evolution of oxygen decreases. In chlorate producing cells, because there is no separating membrane to confine the anodic and cathodic products, the oxygen becomes mixed with the hydrogen evolved at the cathode and, therefore, there is a danger of forming an explosive mixture. Similarly, the evolution of too much chlorine could make the cell combustible or explosive (Tilak & Chen, 1999). It is not desirable to operate chlorate production cells with greater than 2.5% oxygen in the evolved hydrogen. Thus, the amount of oxygen evolved from an anode used for the electrolysis of halide solutions is important for both safety reasons and current efficiency (Alford & Warren, 1994).

Function 3: Passivation of steel cathodes

Cr(VI) is known to passivate steel, as its reduction forms a Cr(III) oxide/hydroxide film (eq. 10) (Brasher & Mercer, 1965) on the cathode in chlorate cells (Tilak & Chen, 1999). This helps slow the corrosion of the electrodes down, thus resulting in savings and reduced contamination of the sodium chlorate product by iron compounds.

2- + - 3+ Cr2O7 + 14H + 6e ⇄ 2Cr + 7H2O (10)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 17 The purity of the sodium chlorate product is important when it is used to generate ClO2 from sodium chlorate for bleaching. The higher purity sodium chlorate that is obtained when SD is used in the electrolyte has superior performance and is thus preferable for downstream use of sodium chlorate.

Iron oxides may also cause short-circuits and poor electrolyte circulation due to obstruction in the narrow (2-4 mm) electrode gaps. However, a benefit of this corrosion phenomenon is that the surface is continuously renewed, thereby removing deposits consisting of mainly calcium and magnesium compounds (Cornell, 2002)2.

Function 4: Increase of the overall efficiency and energy efficiency of the chlorate process

Suppression of parasitic reactions at the cathode

The main reaction on the cathode is hydrogen evolution from water, eq. 11. Two important side reactions are the reduction of hypochlorite and of chlorate, eqs. 12 and 13. These compete with the chemical (eqs. 2 and 3) and electrochemical reactions of hypochlorite and chlorate (eq. 4) (Cornell, 2002).

- - 2H2O + 2e  H2 + 2OH (11) - - - - ClO + H2O + 2e ⇄ Cl + 2OH (12) - - - - ClO3 + 3H2O + 6e ⇄ Cl + 6OH (13)

The reduction of hypochlorite and chlorate ions on the cathode by parasitic reactions may cause a lowered current efficiency, thus leading to increased energy consumption.

Additions of SD to the electrolyte have long been known to suppress reactions (12) and (13). A thin film, less than 10 nm thick, of chromium hydroxide, Cr(OH)3·xH2O is formed by reduction of Cr(VI) during cathodic polarisation (see eq. 8). Cornell (2002) has documented that the film electrochemically hinders the reduction of hypochlorite and chlorate; on the other hand, the hydrogen evolution reaction can still take place on the cathode after SD addition. During cathodic polarisation, the film grows at a rate that decreases with time until a final film thickness is reached. Thus, the film inhibits not only the reduction of hypochlorite and chlorate but also limits its own growth (Cornell, 2002).

- The Cr(III) film acts as a temporary diaphragm that is permeable to H2 and OH but prevents access of hypochlorite ions to the cathode. As hypochlorite is less available to the cathode surface, its electrochemical reduction (eq. 12) is hindered. Notably, this diaphragm is present only during production i.e. when the electrolysis current is on. It is oxidised immediately to SD after the electrolysis current is stopped by the active chlorine species present in the electrolyte.

Another important cause of lowered current efficiency is oxygen production, as discussed earlier. Oxygen production normally results in <2.5% oxygen content in hydrogen. By control and

2 Salt contains sulphate and it accumulates in the cell solution. When the sulphate level becomes high enough, a part of the cell solution is taken out of the process circuit and sulphate is precipitated by calcium 2+ 2- salts (batch process): Ca + SO4  CaSO4(s). The precipitate is settled and filtered out. This calcium sulphate “cake” may contain small amounts of SD. The second step of the process is to remove excess Ca 2+ 2- by precipitating it out by sodium carbonate. Ca + CO3  CaCO3(s). This precipitate is also filtered out of system. The amount of calcium sulphate (and calcium carbonate) formed depends on salt quality.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 18 optimisation of the process parameters, including the addition of SD as described above, the production of oxygen can be minimised (IPPC, 2007) resulting in increased current efficiency and reducing safety risks.

Energy consumption at a sodium chlorate plant Usually, in a production plant, the chlorate cells are operated in the cell voltage range 2.75 – 3.6 V at an average current efficiency of 95% (IPPC, 2007)3. Energy consumption is directly proportional to the voltage and inversely proportional to the current efficiency (IPPC, 2007). From a historical perspective, it is possible to say that the energy consumption of chlorate manufacture decreased to one-third during a little more than 100 years. The first sodium chlorate plant started 1886 and the energy consumption was 15,000 kWh/t of crystallised product. In addition to the electrical energy requirement for electrolysis, additional energy is required to drive other plant equipment such as pumps, compressors and centrifuges amongst other operations. This can contribute significantly to the total energy requirement. With modern technology, the total consumption of electrical energy is 5,000 – 6,000 kWh/t of crystal product. Typical ranges of energy consumption for electrolysis and ancillary equipment are shown in Table 2-2 below.

Table 2-2: Electricity consumption parameters in a chlorate plant (according to BREF) Parameter Typical ranges Electrical energy use for electrolysis 4,700-5,200 kWh/t chlorate Electrical energy use for other electrical equipment (pumps, compressors, etc.) 100-500 kWh/t chlorate Total energy use 5,000-6,000 kWh/t chlorate Source: BREF (IPPC, 2007)

Finally, energy consumption can also be controlled by controlling the impurities in the salt (NaCl). These impurities can ‘blind’ both the anode and cathode surface and deactivate the anode. Efficient brine purification is, therefore, important even if it generates an increased amount of solid waste (IPPC, 2007).

Conclusion

Overall, the beneficial action of the SD can be summarised in Table 2-3.

Table 2-3: Important roles of sodium dichromate in the chlorate process Action Effect Reaction with H+ and OH- (pH Formation of Cr(III) on the cathode buffering)

Improvement of current energy Controlling the evolution of O2 Cr(III) film prevents competing efficiency and thus of yield and reduces the consumption of parasitic reactions at the cathode reduction of operating costs energy

Improvement of safety of process Controlling the evolution of O2 and Cl2 and explosive mixtures Protection of anode Controlling the evolution of O2 provides corrosion protection

3 The IPPC (2007) quotes a range of 2.75 – 3.6 V and 2.6 – 3.5 V. To ensure consistency in the analysis, this AoA will use the latter range and 3.1 V as a mid-range cell voltage value.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 19 Table 2-3: Important roles of sodium dichromate in the chlorate process Action Effect Reaction with H+ and OH- (pH Formation of Cr(III) on the cathode buffering) Protection of cathode Cr(III) passivates steel and protects it from corrosion Improvement of sodium chlorate Avoidance of corrosion prevents product quality contamination of the chlorate product by iron compounds Improvement of chlorine dioxide Prevention of contamination of product quality chlorate product ensures high quality ClO2 product in downstream use 2.2 Conditions of use and technical feasibility criteria

2.2.1 Approach to information collection and overview of technical feasibility criteria

The development of technical comparison criteria for SD and its alternatives has been based on a combination of consultation between the independent third party that has authored this AoA and the applicants, and the review of available scientific literature.

Through the use of a detailed written questionnaire (disseminated in December 2012) the applicant was asked to provide details of the (ideally) measurable, quantifiable technical performance criteria which SD (or the SD-based technology) meets and that any alternatives (substances and technologies) would also need to meet before they are seriously considered as replacements. These criteria could relate to issues of molecular structure, solubility, transformation products, product purity, energy consumption, etc. anything that is relevant and important to the process in which SD is used and the roles it plays in that process.

In parallel, scientific literature delving into the parameters of the chlorate process and the assessment of the technical suitability of specific alternative technologies was collected and analysed (with the assistance of the applicants) and has been incorporated into the analysis. The role of SD in meeting the four main tasks in the production of sodium chlorate has been described above in Section 2.1.2. The technical feasibility criteria that shall be used in the assessment of the technical feasibility of selected alternatives are as follows.

 Formation of protective film that is permeable to hydrogen and impermeable to hypochlorite  Control of oxygen formation  Cathode protection  pH buffering  Current efficiency and energy consumption  Solubility in electrolyte  Impurities control.

The discussion below explains the relevance and importance of the criteria for the chlorate process and presents in more detail the threshold values (or ranges) that will be used in Sections 4 and 5 for the comparison of alternatives to SD.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 20 2.2.2 Formation of protective film permeable to hydrogen

Importance of the technical criterion

As explained earlier, SD acts to limit side reactions which themselves limit the achievable process efficiency (both electrical and chemical) and can cause potential safety concerns due to the formation of oxygen. During the chlorate production process, SD, a source of Cr(VI), is reduced to Cr(III) by cathodic polarisation (Cornell, 2002). The equation for the reduction from Cr(VI) to Cr(III) can be found in section 2.1.2, equation 10. This Cr(III) is present only during production i.e. when the electrolysis current is on as it is oxidised immediately to SD if the electrolysis current is stopped due to the presence of hypochlorite. This less than 10 nm thick Cr(III) hydroxide film on the cathode - acts as a temporary diaphragm that is permeable to H2 and OH , but prevents hypochlorite ions from accessing the cathode (Ahlberg Tidblad & Lindberg, 1991). This hinders the electrochemical reduction of hypochlorite and chlorate, yet allows for hydrogen evolution (Lindbergh & Simonsson, 1991) that is an inherent by-product of the process. The hydrogen evolution equation is:

+ - 2H + 2e  H2 (14)

- - - - ClO3 + 3H2O + 6e  Cl +6OH (15)

On the other hand, in relation to hypochlorite, as stated above, the Cr(III) hydroxide film on the cathode effectively hinders the undesired hypochlorite and chlorate reductions, while still allowing for the required hydrogen evolution reaction to occur (Lindbergh & Simonsson, 1991). This is important because it allows for an increase of production and current efficiency, and minimises cathode corrosion. For this effect to take place, as well as the limiting of oxygen production at the anode, the concentration of SD should be a minimum of 3 g/L. Hindering hypochlorite reductions (eq. 16) is also important to in controlling the rate of oxygen formation reactions (see below, eq. 17). (Cornell, 2002).

- - - - ClO + H2O + 2e  Cl + 2OH (16)

Threshold value

There is no suitable threshold value that can be used in the comparison of alternatives to SD. A thin, permeable, film must be generated by any alternative substance or technology, in a fashion similar to the film generated in the presence of >3 g/L SD in the electrolyte.

2.2.3 Solubility in electrolyte

Importance of the technical criterion

SD is very soluble, with a water solubility of 2355 g/L at 20 °C (Munn, et al., 2005). SD’s solubility allows it to be present in solution in the electrolyte and thus be reduced to Cr(III) on the cathode. An insoluble substance limits the rate at which it is able to partake in reactions with other species in solution and thus its ability to act as an effective pH buffer is drastically reduced. Furthermore, insoluble particles contribute to sludge and may interfere with the flow of electrolytes and product solutions during the process4.

4 e.g. the reason for the removal of cathode corrosion sludges is in part due to their insolubility.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 21 Threshold value

No specific threshold can be set; in general, the solubility of any alternative substance must be as high as possible.

2.2.4 pH buffering and control of oxygen formation

Importance of the technical criterion

One of SD’s key uses is as a pH buffer and equations 8 and 9, under section 2.1.2, illustrate how SD acts as one. The buffering of the pH allows for many SD benefits as it facilitates corrosion inhibition, oxygen evolution control, and maximisation of current efficiency. Without effective buffering, pH- influenced reaction inefficiencies would increase; a decrease in pH would result in more chlorine being formed, and, an increase would result in more oxygen being formed. Electrochemically produced oxygen in a chlorate cell may be detrimental to the anode, limiting the coating lifetime (Cornell, 2002). Additionally, chlorine and oxygen gases would contaminate the hydrogen gas co- product and might not only decrease its value (if used as a raw material for later syntheses or sold) but also decrease process safety (as discussed elsewhere). Therefore, it is very important to maintain the optimum pH to maximise the electrolytic cell efficiency and ensure the safety of the plant (Tilak & Chen, 1999). Finally, unfavourable pH may also result in undesired precipitation of compounds in the electrolyte (Hedenstedt & Edvinsson-Albers, 2012).

There are several possible side reactions leading to the formation of oxygen, and the selectivity for oxygen formation depends on several factors: the concentration of hypochlorite, the current density, the chloride concentration, the temperature, and on the anode coating (Cornell, 2002). Hypochlorite is an important source for oxygen in chlorate electrolysis, and can form oxygen via a number of reactions (eqs. 17 and 18):

- - 2ClO  O2 + 2Cl (17)

- + - - ClO + H2O  2H + Cl + O2 + 2e (18)

Without hypochlorite, and at potentials lower than the reversible potential for chlorine evolution, oxygen evolution from water discharge is the main reaction (eq. 7, see Section 2.1.1), and is an electrochemical reaction (Cornell, 2002). However, it has been pointed out that there are difficulties in separating the different contributions that generate oxygen (Nylén, 2006).

These processes occur at the anode and thus the Cr(III) film that is formed at the cathode does not limit these reactions. However, SD is still important in minimising these reactions due to its pH buffering properties and because, when the other side-reactions are limited, there is less HClO/ClO- available to decompose into oxygen.

Threshold value

The pH is kept between 6.0 and 6.5 to minimise anodic oxygen formation (Cornell, 2002). The acidic anode surface not only suppresses oxygen evolution, but also favours chloride oxidation. Having the pH more acidic would suppress oxygen evolution further, but would also decrease the rate of chlorate-producing reactions (Nylén, 2006). Importantly, a minimum SD concentration of >3 g/L in the solution is required to hold the pH in the range of 6.0 to 6.5 and below this value SD begins to fail as a pH buffer.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 22 According to the relevant BREF Document, under the conditions used in the sodium chlorate industry, a 2-2.5% oxygen content in hydrogen can be achieved. The explosive limits of H2 in O2 are 4.65% the lower and 93.9% the upper (Li, et al., 2007). From an applicant-specific perspective, the safety limit for oxygen in hydrogen is 4.0% on a dry basis to avoid explosions. Therefore, while the concentration of O2 should ideally be below 2.5% (to be on par with SD), 4.0% is the safety limit which an alternative must not exceed.

2.2.5 Cathode protection

Importance of the technical criterion

The Cr(III) hydroxide film that forms on the cathode in chlorate cells passivates the steel, and slows the corrosion of the electrode which occurs at shutdown in the presence of hypochlorite. As has been mentioned before, this effect limits the side reactions that reduce process efficiency but it also has other beneficial effects. It also reduces contamination of the sodium chlorate product and reduces cost by decreasing the time required for maintenance of the equipment. The corrosion of steel cathodes produces sludge (e.g. iron oxides) over time and these must be periodically removed. The greater the rate of corrosion, the more often this process must be carried out. Maintaining an effective concentration of SD in the system helps prolong the time between maintenance; the operating limit for the concentration of SD required for the prevention of corrosion is a minimum of 3 g/L. Below this value, cathodic corrosion in the presence of hypochlorous acid will occur at an increased rate (Speight, 2002).

Threshold value

No threshold for the degree of tolerable corrosion has been set. However, sodium chlorate manufacturers may have a minimum acceptable lifetime of a single cathode that may be company specific. This can be assumed to be 8-16 years or even longer as Kemira can confirm that a 20-year lifetime for Fe-base cathodes is achievable. The lower end of this range, 8 years, will be used as a technical feasibility criterion when comparing alternatives to SD.

2.2.6 Current efficiency and energy consumption

Importance of the technical criterion

The presence of SD limits electrochemical side reactions that consume electrical energy and, thus, decrease the overall process efficiency. This has been described by the criteria above but the current efficiency and energy consumption of the process are important measures that are critical to both the technical and economic feasibility of the process. As electrical energy represents the largest part of the overall cost of sodium chlorate manufacture, maintaining a high current efficiency is of paramount importance. Theoretically, the amount of electrical charge required to produce a tonne of sodium chlorate is 1,511 A.h per kg of chlorate5. However, the efficiency of any process is not 100% and thus the actual energy required is greater. Cell current efficiency is a function of the cell operating characteristics and cell design. Cell operating characteristics include flow rate, pH, and temperature, for example. Generally, cell current efficiencies in the range of 93-96% can be

5 Equation 6 shows the overall reaction for the production of NaClO3. This reaction requires 6 electrons per chlorate atom produced or 6 Faradays (160.8 A.h/mol) per mol of chlorate or 1,510.8 A.h/kg.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 23 achieved using metal electrodes (Tilak & Chen, 1999). The overall energy consumption of a chlorate cell is in-turn a function of current efficiency and cell voltage (Tilak & Chen, 1999):

P = 1,511E / (ԑ/100) (19)

Where P is energy consumption (kWh/tonne), ԑ is the current efficiency (%), and E is cell voltage (volts). As can be seen, the energy consumption is inversely proportional to the current efficiency (IPPC, 2007).

As stated in Table 2-1, a typical operating voltage for a cell is between 2.6-3.5 V. Assuming a voltage of 3.1 V and a cell efficiency of 90% would predict an energy consumption of 5,204 kWh/tonne of chlorate compared to a 4,930 kWh/tonne if the cell was 95% efficient. This is a potential saving of ca. 274 kWh/tonne if a high efficiency can be achieved with a concomitant reduction in the release of greenhouse gases.

SD must be maintained in the range of 3-6.5 g/L of electrolyte and in this range, the efficiency of the process is acceptable; above that range, no benefit may be apparent and, in fact, a higher concentration may hinder the electrical efficiency of the anode (Cornell, 2002). Thus, it is beneficial for the process to keep the SD concentration as low as possible while still enabling the performance of its other tasks (e.g. pH buffering, corrosion inhibition).

In addition to the electrical power consumed by the electrolysis cell, a smaller amount of additional energy is required to run ancillary equipment such as pumps, mixers and centrifuges to prepare and transport electrolyte as well as to recover the chlorate product (IPPC, 2007). The mid-range value for electricity consumption of other electrical equipment is assumed to be 300 kWh/tonne bringing the total theoretical energy consumption at 95% cell efficiency to 5,230 kWh/tonne chlorate when using SD.

Threshold value

The minimum acceptable current efficiency or power consumption values for the applicant may differ to those of other manufacturers of sodium chlorate depending on the specific production parameters of each plant. Specific information from the applicant is considered confidential. Taking into account what is shown in the relevant BREF Document, the following threshold values will be considered in this analysis.

Table 2-4: Energy efficiency and consumption thresholds for potential alternatives for SD Applicant-specific thresholds used Parameter Literature thresholds in this analysis Minimum energy efficiency Minimum: 90% Minimum: #A#%* Ideal: >95% Maximum energy 5,700 kWh/t chlorate (see Table 2-2)- consumption '''''''''' '''''''''''''''' '''''''''''''''' '''''''''#A#''''''' ''''' '''''''''''''' ''''''' ''''''''''''''''' '''' '''''''''''''''

2.2.7 Control of impurities

Importance of the technical criterion

Chlorate chemistry is highly vulnerable to the presence of impurities; therefore, the presence of impurities is of great concern to both the chlorate manufacturer and to the users of the chlorate.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 24 At present, with the use of SD, the typical level of impurities is below 0.5% by weight with chromium present at very low levels, typically below 5 ppm, as shown in Table 2-5.

Table 2-5: Typical sodium chlorate product specification Attribute Limit

NaClO3 overall purity 99.5 wt% NaCl 0.12 wt% Moisture 0.20 wt% Chromium <5 ppm Source: Mendiratta & Duncan (2003)

If SD were to be replaced by an alternative substance or technology, a different impurity profile would arise for the chlorate product and these new impurities might well affect the efficiency and stability of the ClO2 generation reaction on the premises of the customers of the applicant (i.e. during the bleaching processes used in the pulp and paper industry). What is referred to here is the so-called ClO2 ‘puff’. This is the thermal decomposition of ClO2 in a heterogeneous, exothermic and autocatalytic reaction. This reaction might be rather violent given high partial pressures of ClO2 in the air, exceeding 10.1 kPa (Kack & Lundberg, 2010). Initiators of ClO2 puffs may include (Ragauskas, undated):

 Reactive metals, such as iron  An electric spark or static electricity  A temperature rise above 100°C  Organic contaminants, especially hydrocarbon greases, oils, and rubber  Dust and rust particles  Sunlight  Sudden pressure fluctuations  Contact with certain chemicals, apart from hydrocarbons, might also cause decomposition. These chemicals include carbon monoxide (CO), mercury (Hg), sulphur (S), phosphorous (P) and potassium hydroxide (KOH) (Lewis, 2000).

Moreover, when sodium chlorate is used for treatment of water intended for human consumption only levels of up to 1 ppm/kg sodium chlorate is allowed for seven specified heavy metals (in accordance with standard EN 15028).

In conclusion, any new impurity has to be evaluated as to whether it is compatible with the ClO2 process.

Threshold value

Each impurity has to be considered separately. With alternatives to SD, one particularly needs to consider risks for the ClO2 process from the presence of metals even at the ppm level.

2.2.8 Summary of technical feasibility criteria

Table 2-6 summarises the analysis presented above on the technical feasibility criteria that will be used for the assessment of the technical feasibility of alternatives to SD. Where applicant-specific information diverges from the literature values, the former is provided instead, but it is confidential.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 25 Table 2-6: Summary of technical performance criteria of sodium dichromate Primary relevance SD and Chlorate Relevant threshold Technical feasibility replacement process and value or ideal Notes criteria substances quality of range chlorate output Formation of protective  No specific A sufficiently robust film that is permeable to threshold can be diaphragm should be hydrogen and identified deposited to prevent impermeable to parasitic reactions hypochlorite Solubility in electrolyte  Highly soluble – as Solubility of SD: high as possible ca. 2,355 g/L pH buffering and control   pH: 6.0 to 6.5 This links to the of oxygen formation O2: ideally, less presence of a minimum than 2.5% by of 3 g/L Cr(VI) in the volume of O2 in H2 electrolyte with a maximum of 4.0% Cathode protection   Minimum cathode lifetime of 8 years (20 years achieved by the applicant) Current efficiency and  Energy efficiency: Threshold values may energy consumption #A#% or more, vary by chlorate plant ideally >95% ''''''''''''#A#'''''''''''' '''''' '''''' ''''''''''''''''''' '''''''''''''''' Total energy consumption (electrolysis and auxiliaries): 5,700 kWh/t chlorate or less Control of impurities   Each impurity must Typical level of iron is ≤ be considered 1 ppm. When used for separately. Metals treatment of water could be intended for human particularly consumption only levels detrimental to ClO2 of up to 1 ppm/kg generation sodium chlorate is allowed for seven specified heavy metals (EN 15028)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 26 2.3 Summary of functionality of sodium dichromate in the “Applied for Use”

The information in the preceding parts of Section 2 are summarised in the Table 2-7 below.

Table 2-7: Parameters for SD use in sodium chlorate manufacture and assessment of alternatives Functional aspect Explanation - Tasks performed by pH buffer for the electrolyte, to maintain process parameters to ensure rate of ClO3 the substance forming reactions remains feasible Suppression of oxygen evolution to prevent formation of explosive atmospheres Cathode protection to minimise maintenance costs and to maintain product purity Maintain current efficiency to ensure economic feasibility Physical form of the SD is purchased by the applicant in solution form to minimise (to the extent possible) product worker exposure from handling solid SD. SD is added as an aqueous solution (60-70% w /w) The sodium chlorate product is sold as a white crystalline solid or as aqueous solutions Concentration of the Unintentional presence in the chlorate product. <5 ppm (<0.0005%) total chromium, substance in the of which only some is Cr(VI), is present in the sodium chlorate product marketed product Critical properties and Ability to form a protective film which is permeable to hydrogen and impermeable quality criteria the to hypochlorite – this suppresses the side (parasitic) reactions. If these side reactions substance must fulfil take place, they will limit the evolution of hydrogen, reduce current efficiency and result in increased oxygen concentration which can lead to explosion through mixtures with hydrogen Solubility in electrolyte – must be highly soluble and must not interfere with process and increase need for sludge removal pH buffering and control of oxygen formation- must provide a stable pH which ensures corrosion inhibition, oxygen evolution control, and maximisation of the efficiency of the process Cathode protection (corrosion inhibition) – must limit frequency of maintenance of cathodes and sludge removal Current efficiency and energy consumption – must maintain high current efficiency and low energy consumption, to ensure the economic viability of the process (energy is the largest production cost component) Control of impurities – must not introduce impurities in the chlorate product and prevents the presence of impurities which may affect the efficiency of the chlorine dioxide production reaction by downstream users Frequency of SD is added to the process periodically when process monitoring indicates that its substance use and concentration needs to be adjusted. Typically, this occurs a few times a year as usage quantities indicated in the CSR. Small amounts of SD are lost during the process, requiring the addition of '''''#B#''''''' kg/tonne of sodium chlorate product ''''''''' ''''''''#A#' ''''''''' ''''''''''''''''''''''''. The total tonnage of SD used by the applicant is at the low end of the 1-10 tonnes per year based on anhydrous SD (see further detail in Section 3.1) Process and Process pH Typically, between pH 6.0-6.5. performance and O2 Ideally less than 2.5% O2 in H2 by volume with 4.0% as a safety limit constraints concerning generation for the applicant the use of the Acceptable Minimum 8 years substance cathode lifetime

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 27 Table 2-7: Parameters for SD use in sodium chlorate manufacture and assessment of alternatives Functional aspect Explanation Energy Greater than #A#%, ideally over 95% ''''''''''''''' ''''''''''''''''#A#''' ''''' consumption ''''''' ''''''''''''''''' '''''''''''''''''; total energy consumption less than 5,700 and efficiency kWh/t chlorate Concentration The concentration of SD in the electrolyte and an ideal range of in electrolyte concentrations has been established, 3-6.5 g/L. Below that range, SD cannot perform its intended tasks (energy consumption increases affecting the economics of the process, pH is not buffered sufficiently this making the process unstable, corrosion phenomena increase). Above the ideal range, no discernible benefit may arise. Impurities Each impurity has to be considered separately due to its variable effect on the reactions the chlorate will participate in Current 1-3 kA/m2 density Temperature Process temperatures may vary and are confidential but typically in the region of 60-90 °C Conditions under The use of SD fulfils many roles and if it were to be eliminated, alternative methods which the use of the of controlling pH, corrosion and process efficiency would need to be found in order substance could be to have a feasible process without the use of SD. Without a way of fulfilling these eliminated roles, the use of SD cannot be eliminated, as the chlorate production process would become too inefficient, thus uneconomical Customer The presence of specific impurities may be of particular importance for the efficiency requirements of the chlorine dioxide production process by downstream users. For example: total associated with the chromium content <5 ppm in sodium chlorate as well as typical iron content of ≤ 1 use of the substance ppm Industry sector and Other than contractual requirements on the purity of the final sodium chlorate legal requirements for product, no industry sector or legal requirements that require the use of SD apply. technical acceptability Application for water purification intended for human consumption sets a limit on that must be met heavy metals <1 ppm (EN 15028)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 28 3 Annual tonnage

3.1 Tonnage band

Confidential annual tonnage (2013-2014): ''''#B#''' tonnes of SD.

Annual tonnage band: 1-10 tonnes per year based on anhydrous SD.

The following table explains the tonnages of the chlorate manufactured and the SD consumed by the applicant in the years 2013-2014. The applicant has two locations where sodium chlorate is manufactured and one location where sodium chlorate is used in the manufacture of chlorine dioxide. The table shows that SD consumption varies year by year. The amount of SD needed is determined by the amount lost. Larger losses can be caused by process disturbances during the crystallisation process: smaller particles are more difficult to wash and more SD ends up in the chlorate product. High crystallisation temperature, especially in the summer can result in higher consumption of SD. On the other hand, there is a slight possibility to decrease the use of SD by optimising the process conditions. Kemira already uses low sulphate salt meaning this parameter has been optimised already as the sulphate is one reason for increased SD use. '''''' ''''''' ''''''''''''''''' '''' ''''''' ''''''''''''''' '''''''''''''''''''' '''' ''''''''''''''' ''' '''' ''#B#''''' '''''''''' ''''''' '''''''''''''''' ''''''''''''''''''' ''''''''''''' '''' ''''''''''''' '''''''''''''''' ''''''' ''''''' '''''''''''''' ''''''''''''''''''''''''' '''' '''''' ''''''' '''''' ''''''''' '''''' '''''''''''''' '' ''''''''''''''' ''''''' ''''''''' '''''''' '''''''' '''' '''''' '''''''''''

Table 3-1: Sodium chlorate manufacture and SD consumption by the applicant ''''#B#''''' ''''''''' '''''''''''''''' '''''''''''''''' '''''''''''''' ''''''''''''''' '''''''' '''' ''''' ''''''''''''''' ''''''''' ''' ''''' '''''''''''''''' '''''''''''''''' '''''''''''''' '''''''''''''''' '''''''''''''''' '''''''''''''''' ''''''''''''' '''''''''''''''' '' ''''' '''''''''''''''' ''''''' '''' ''''' '''''''''''''''' '''''''''' ''''' '' '''''''''''''''''''' '''''''''''''' '' '' '''''''''''''' '' '''''''' '' ''''''''''''''' '' '''''''''''''''' ''''''''''' '' '' '' '''''''''''''''' '''''''''''''' '' '' ''''''''''''' '' ''''''' '' ''''''''''''' '' '' '''''''''''''' '' ''''''''''' '' ''''''''''''''''''''' '' '''''''''' '' '''''''''' '' '''''' '' '' ''''''''''' '' ''''''''''''' '' '''''''' '' '''''''''' '''''''''''''' ''''''''''''''' '' '''''''' '' '' '''''''' '' '' ''''''''''''''''''' ''''' ''''''''''''' '''''''''''''' '''' '''''''''''''''''''''' '''' '''''''''''' '''''''' ''''''''''''''' ''''' '''''''''' ''''''''' ''''''''''''''' '''''''''''''''''''' '''''''''''''''''

It is worth noting that the consumption of SD in the manufacture of sodium chlorate by the consortium of companies of which the applicant is a member is at the low end of the 10-100 t/y range. This tonnage is very low compared to the overall tonnage registered: ECHA’s Dissemination Portal indicates that the substance was registered at the 10,000-100,000 t/y band. This makes the “Applied for Use” of the substance one of the rather ‘niche’ applications for SD. The CSR also explains the use of predominantly closed loop systems in the industry which greatly reduce releases of and exposure to chromates during the manufacture of sodium chlorate.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 29 3.2 Trends in the consumption of sodium dichromate

In the period 2007-2012, the applicant’s consumption of SD in the chlorate process has generally remained unchanged. In the long-term, the rate of consumption is steady and it is not expected to change in the future. The applicant does not foresee changes in the consumption of SD unless the process is disturbed, as described above. 3.3 Form and usage of sodium dichromate

During the chlorate production process, SD is dosed when required to keep a constant level in the electrolytic cell. The number of times that SD is added varies by production plant but generally takes place a few times per year and the quantities added are very small as described in the CSR. The addition is done to compensate for small losses with:

 Chlorate product: the final product contains traces (<5 ppm or 0.0005% w/w) of chromium (Mendiratta & Duncan, 2003)

 Filter sludge: solids (typically corrosion products) accumulate at the bottom of the electrolytic cell and the process tanks as sludge. The sludge is removed from the cells during scheduled maintenance and the electrolytic cells are periodically washed using hydrochloric acid. The waste acid is filtered and the sludge containing iron and chromium is filtered off. The mother liquor (the part of a solution that is left over after crystallisation) is sometimes filtered before the crystallisation stage. This adds to the chromium-containing sludge (IPPC, 2007).

w The substance is added in the form of solution, the concentration of which is typically 60-70% /w (as Na2Cr2O7·2H2O). The final concentration of SD in the chlorate cell is 3-6.5 g/L. According to the BREF Document for Large Volume Inorganic Chemicals (Solids), the dose rate for SD is 0.01-0.15 kg/tonne of sodium chlorate product (IPPC, 2007). Information from the applicant suggests that his consumption of SD is within this range at ''''''#A#'''''' kg/tonne of sodium chlorate.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 30 4 Identification of possible alternatives

4.1 List of possible alternatives

This AoA evaluates a broad range of alternatives, as the applicants wish to demonstrate that very thorough research for the identification of suitable alternatives has been undertaken.

This section presents an assessment from a screening of the available information. The alternative substances and technologies presented in Table 4-1 were identified through literature research and industry consultation, have been screened as, in principle, realistic potential alternatives for the replacement of SD and are further assessed in Section 5 of this AoA. Several other alternatives have been identified (see rest of Section 4) but were subsequently eliminated as infeasible and/or unsuitable.

Table 4-1: Shortlisted potential alternatives for the replacement of sodium dichromate Alternative substances CrCl (other trivalent chromium substances are a Chromium (III) chloride 3 possibility, such as Cr(OH)3, Cr2O3) Sodium molybdate Na2MoO4 Cathodic coatings based on metals Cathodes coated using Na MoO , FeCl (not present Molybdenum-based coatings 2 4 3 in the electrolyte) Other technologies Two-compartment electrolytic cell systems

It must be noted that the use of SD in the manufacture of sodium chlorate is the current ‘state-of- the-art’ not only within the EU but also elsewhere in the world. As will be discussed later, the above alternatives currently find no commercial use; indeed, EU-based chlorate producers are at the forefront of research for the development of low-Cr(VI) or Cr(VI)-free processes for the manufacture of sodium chlorate. 4.2 Description of efforts made to identify possible alternatives

4.2.1 Overview

This AoA document has been prepared by an independent third party. This Section presents both the efforts made by the applicant to research and develop alternatives and those by the independent third party to identify in the literature efforts by various stakeholders towards the development of alternatives.

4.2.2 Research and development by the applicant

Introduction

The process of chlorate manufacture is well understood and has been described extensively in the IPPC BREF - Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals (2007). The BREF describes the historic improvements that have been made to the chlorate process

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 31 and highlights the importance of SD as a necessary additive, as well as the steps taken to reduce its use (recirculation and recycling of solutions) and minimise exposure.

The removal of SD and other Cr(VI) species from processes is and has been of high interest for many decades, but in spite of extensive research, an alternative that fulfils the role of SD in a manufacturing process environment has not been developed at the industrial scale. Instead, the trend has been to minimise the output of chromium from the process and work towards a predominantly closed loop system.

Some members of the SDAC have been actively involved in research and development. Several PhD projects and a number of published papers have been sponsored in part by SDAC companies. In addition to academic research, attempts to apply alternative technologies to the production of sodium chlorate have been made, including pilot production scale trials. Although the removal and reduction of the use of Cr(VI) has been an objective of these trials, they have not succeeded in completely removing its presence.

Past and current R&D activities of the applicant

Kemira has generally not undertaken in the past R&D specifically aimed at developing a Cr(VI)-free process for the manufacture of sodium chlorate. In general, there has not been any need to develop new technology before SD placed on Annex XIV of the REACH Regulation.

Some research was undertaken on Ru-based cathode coatings and Ti-Ru alloy cathodes, but these were aimed at the improvement of other parameters of the process rather than the elimination of SD from the process. Additional research was also undertaken outside the EU on two-compartment electrolytic cells.

Future R&D activities of the applicant

''''''''''''' ''''''''''' ''' '''''''''' ''''''' ''''' ''''''''''''''' '''''''''''''''' '''''' ''''''''''''' '''' '''''''''''' '''''' '''' ''''''' '''''''''''' '''''''''''''' ''''''' ''''''' '''''''''''''''''' '''''''''''''''' ''''''' '''''''''''''''''''''' '''''''''''' ''''''''''''''' ''''''' '''''''''''''''''''''''' '''' '''''''''''''' '''''''''''''''' '''' ''''' '''''''''''''''''''''' ''''''''''''' ''''''' '''''''''' '''''''''''''' ''''''' ''''''''''''''''''' '''' ''''''' '''''''''' '''''''''''''''' '''''''' ''''''' ''''''' '''''''''''''''''''''' '''''''''''' ''''''' '''''''''''''''''''' '''''''''' '''''''' ''''' '''''''''''' ''''''' ''''''''''''''''' ''''''''''''''' ''''''' '''''''''' ''''''''''''''''''''''' ''''''''''''''''''' ''''''' ''''''''''''''''''' '''' ''''''''''''''''''''''''''''''''''''' ''''''' '''''''''''''''''''''' ''''''''''''''''''' ''''''''''''' ''' ''''''' ''''''''' ''''''''''''''''''' ''''''' ''''''''''''' '''''''''''''''''''''' '''''''#F#'''''''''''''' '''''''''' '''''' '''''''' '''' ''''''''' ''''' ''''''' '''''''''''''''''''' '''' ''''''''''''''' ''''''' '''''''''''''''''' ''''' ''''''''' ''''''''''''''''''''' ''''''''''''' '''''''' ''''' ''''''''''''''''' ''''''''''''' ''''''''' ''''''' '''' ''''''' ''''''''''' '''''''''''''''''''''''' ''''''' '''''''''''''' ''' ''''''' '''''''' ''''''''''''''''''' ''''''''''''''''' '''''''''' ''''''''''''''''''''''''' ''' ''' ''''''''''''''' '''''''' ''''''''' ''''''' ''''''' ''''''''''''''' ''' '''''''' '''''''''''''''''''''' ''''''' '''' '''''' ''''''''' '''''''' ''''''''''''''''''''' '''''''''' ''''''' ''''''' ''''''''''''''''' '''''''''''''''''''' ''''''''''''''''''''''''''' '''' '''''''' '''''''''''''''' '''''''''''' ''''''' '''''' ''''''' ''''''''''''' '''''' ''''''''''' ''''' ''''''''''' ''''' '''''''' '''''''''''''''''''''' ''''' '''''' '''' ''''''' ''''''''''''''''' ''''''''' ''''''' ''''''''''''''''' '''''''''''''''''''''''' '''''''' ''''''''''''''''''' ''''''''''' ''''' ''''''''' '''''''''''' '''' '''''''''

4.2.3 Literature searches

Introduction

The following paragraphs summarise information that is available in the scientific literature on efforts that have been made towards identifying and developing alternatives to SD and to SD-based chlorate cells. The tables provided below summarise the key findings of the identified literature sources.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 32 Alternative substances used as additives to the chlorate process

Alternative 1: In-situ generation of dichromate from trivalent chromium (chromium (III) chloride)

Patent applications have been published describing the use of trivalent chromium (Cr(III)) as a replacement of SD in the chlorate process. Two are the key sources of information:

 A patent by Dobosz (1987), associated with Canadian interests  A patent application by Hedenstedt & Edvinsson-Albers (2012), associated with AkzoNobel (EKA).

A number of key points have been highlighted in this research:

 Engineering requirements: a separate vessel, for example a tank, for the in situ formation of Cr(VI) from a Cr(III) compound might be required

 pH levels: according to Hedenstedt & Edvinsson-Albers, Cr(III) can be oxidised to Cr(VI) by sodium chlorate and hypochlorite under acidic conditions and at elevated temperatures. On the other hand, Dobosz described the process as most effective at pH values between ca. 8 and ca. 10. Generally, its assumed that pH conditions similar to the applicant’s current operating conditions would be sufficient

 Chromate use and presence: Cr(VI) is formed in situ from the addition of a suitable Cr(III) compound. Such a compound is oxidised in a vessel to hexavalent chromium by means of hypochlorite, chlorine, chlorite or chlorate. Suitable Cr(III) substances that could be added include chromic chloride, chromic oxide and chromic hydroxide; CrCI3·6H2O has been suggested as a suitable option. The dosage of the Cr(III) compound could be similar to that of SD in the current conditions of use (2-6 SD equivalents per litre).

Overall, it is clear that under the processes outlined by these patents and patent applications, Cr(VI) is still present the electrolyte but is not handled by the workers in the make-up and dosing of the electrolyte solution. This would reduce potential exposures of workers to Cr(VI). However, exposure to Cr(VI) would still result from other processes involving the electrolyte such as sampling/testing, cleaning and maintenance and washing of filter cakes. It is estimated that using a Cr(III) compound instead of SD would reduce exposure by approximately 20%.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 33 Table 4-2: Research into the use of in-situ oxidation of Cr(III) Dobosz, 1987 Parameter Details Year 1987 Source (Dobosz, 1987)- Patent Associated company/ Tenneco Canada Inc. research organisation Objective of research or - Developing a method for formation of Cr(VI) useful in the electrolysis of chlorides invention to form chlorates by reaction between a Cr(III) compound and hypochlorite present in an effluent from the chloride electrolysis. In this way, at least part of the hypochlorite ions are converted to harmless chloride ions while providing the needed Cr(VI) from readily-available trivalent chromium compounds. - The process of the invention can be used to effect treatment of the hypochlorous acid-containing condensate, to effect treatment of aqueous chlorate solution to achieve dehypoing (hypochlorite removal), or a combination depending on the hexavalent chromium ion requirement and the amount of oxidising agent available for oxidation. When the condensate is treated with Cr(III), the resulting deactivated condensate containing only chloride ions and chromate ions, then can be used in brine preparation for the cell Relevance to the chlorate High, but priority seems to have been the removal of hypochlorite rather than the process elimination of Cr(VI) for environmental/health reasons Key changes to current - Cr(III) substances that could be added include chromic chloride, chromic oxide chlorate process and and chromic hydroxide notable improvements and - The process may be effected over a wide range of pH but is most effective at pH shortcomings values are from ca. 8 to ca. 10. These pH conditions facilitate dissolution of the Cr(III) and oxidative conversion to Cr(VI). It is preferred to add sodium hydroxide or other suitable alkali to the condensate prior to reaction with the Cr(III) compound - Cr(III) is used to effect dehypoing in the tank to remove hypochlorite and again form Cr(VI) and chloride ions. The Cr(VI) ions so produced are recycled to the brine preparation tank with the mother liquor Presence of Cr(VI) in the Handling of Cr(VI): the invention demonstrates a manner of providing Cr(VI) for use electrolyte in the electrolytic production of chlorates which uses by-product hypochlorite from the chlorate production to oxidise Cr(III) to Cr(VI) Presence of Cr(VI) in electrolyte: Cr(VI) is still present as a result of the oxidation of Cr(III) to Cr(VI)

Table 4-3: Research into the in-situ oxidation of Cr(III) – Hedenstedt & Edvinsson-Albers, 2012 Parameter Details Year 2012 Source (Hedenstedt & Edvinsson-Albers, 2012) - Patent Associated company/ AkzoNobel (EKA) research organisation Objective of research or - Development of a process of producing alkali metal chlorate in an electrolytic cell invention comprising an anode and a cathode, wherein substantially no hexavalent chromium is added to the process from an external source - Provision of an alternative compound entirely substituting or to a large extent substituting Cr(VI) compounds as raw material, while safeguarding a controlled supply of Cr(VI)in the cell electrolyte which is independent on the amount of for example hypochlorite in condensate streams - Provision of a process which facilitates production of alkali metal chlorate wherein Cr(VI) can be provided at an acidic pH whereby necessary pH adjustment can be reduced or eliminated

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 34 Table 4-3: Research into the in-situ oxidation of Cr(III) – Hedenstedt & Edvinsson-Albers, 2012 Parameter Details Relevance to the chlorate Highly relevant process Key changes to current - At least one chromium compound having a valence lower than +6 may be added chlorate process and to at least one process stream containing either alkali metal chloride or alkali notable improvements and metal chlorate or to at least one process stream containing both alkali metal shortcomings chlorate and alkali metal chlorate - Formation of Cr(VI) is made by addition of a the chromium compound with a valence lower than +6 to for in a separate vessel, for example a tank, and oxidised in such vessel to hexavalent chromium (in-situ generation thereof), for example by means of hypochlorite, chlorine, chlorite, chlorate, etc. - Example dosage for the chromium compound having a valence lower than +6 is 2 to about 6 g (calculated as SD equivalents)/L electrolyte solution or from ca. 2 to ca. 20 g chromium/t produced chlorate - Chromium compounds having a valence lower than +6 may be for example chromium halides such as chromium(III) chloride, chromium(III)chloride hexahydrate, and several others, or their mixtures - The examples shown in the patent utilise chromium trichloride hexahydrate

(CrCl3·6H2O) - The chromium compounds can for example be added as salts, aqueous solutions or as melts if the melting point is sufficiently low, for example chromium trichloride hexahydrate having a melting point of 83 °C

- it can be concluded that CrCI3·6H2O crystals can be easily dissolved and that pH is reduced on dissolution of acidic CrCI3·6H2O. Precipitation occurred close to neutral pH and in weakly alkaline solutions, presumably due to formation of

Cr(OH)3(s) or CrO2(s). Sodium chlorate was found to oxidize Cr(III) to Cr(VI) under acidic conditions and at elevated temperatures. Sodium hypochlorite can oxidise Cr(III) to Cr(VI) in strongly alkaline solutions and down to to at least pH 5 or below pH 5. Hypochlorite can even dissolve precipitations formed in neutral solutions and oxidise chromium with a valence lower than +6 to hexavalent state - the molar ratio of hexavalent chromium to chromium having a valence lower than +6 ranges from about 0:10000 to about 1:10000 Presence of Cr(VI) in the Handling of Cr(VI): several examples do not involve Cr(VI), some do electrolyte Presence of Cr(VI) in electrolyte: Cr(VI) always present as a result of oxidation

Alternative 2: Sodium molybdate

Sodium molybdate (Na2MoO4 or its dihydrate Na2MoO4·2H2O) or the Mo(VI) oxide have been proposed as an alternative to SD in the chlorate process. Key sources of information in the open literature include:

 A journal article by Li et al (2007), associated with Canadian interests  A patent by Rosvall et al (2010), associated with AkzoNobel (EKA)  A thesis and journal articles by Gustafsson and colleagues in 2012, associated with the Royal Technical Institute of Stockholm and AkzoNobel (EKA).

A number of key points have been highlighted in this research:

 Oxygen evolution: sodium molybdate interferes with the anodic reactions and results in the release of significant volumes of oxygen, even when used at low concentrations. In the work of Li et al, the measured off-gas O2 level was observed to be high and the H2 explosive upper limit (4.8%) was nearly reached. In the Rosvall et al patent, additions of MoO3 as low as 1-10 mg/L led

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 35 to oxygen release in excess of 3.5% and in some cases well above 4% (Li et al used a concentration of Na2MoO4 of 8 g/L). There is a clear need for adding as little Mo(VI) as possible.

 Buffering: according to Li et al, SD has a better buffer “fit” for the chlorate reaction and Gustafsson et al assert that, to fully replace Cr(VI) or significantly lower the Mo(VI) concentration in the electrolyte, a buffer agent such as phosphate will be needed. Investigation of the films formed on the cathode by co-additions of molybdate and phosphate showed that the molybdenum-containing cathode films became thinner if the electrolyte also contained phosphate during the film build-up. With 80 mM molybdate in the electrolyte a cracked film was formed on the cathode surface. The cathode film that was formed in presence of both molybdate and phosphate, looked similar but was thinner, yet the activation of hydrogen evolution was still as effective. If the amount of molybdate was low (4 mM) and the electrolyte also contained between 10 and 40 mM phosphate no molybdenum film was visible with Scanning Electron Microscopy (SEM) or detectable with Energy-dispersive X-ray spectroscopy (EDX) on the cathode surface. This may be due to competitive adsorption of molybdate and phosphate, where the higher molybdate concentration is necessary for the molybdate to be favoured. Addition of molybdate was found to activate the hydrogen evolution reaction even when no film could be detected, suggesting that a catalytic film was formed which then dissolved, detached or was too thin to be detected by EDX (Hummelgard, 2012).

 Current efficiency (CE): efficiencies documented in the literature are not ideal. Li et al referred to 91% efficiency, while Gustafsson and his colleagues showed that 80 mM Mo(VI), only increased the CE from 80% to about 83% despite being present in a concentration about 30,000 times higher to a comparison cell that contained a small concentration of Cr(VI) (the latter increased current efficiency to 94%). Adding 80 mM Mo(VI) to the Cr(VI)-containing electrolyte did not have a negative effect on the CE, but instead a small positive effect.

 Chromate use and presence: in the work of Rosvall et al and Gustafsson, small additions of SD (ca. 3 mg/L) were deemed necessary for the efficient operation of the cell. Gustafsson et al also suggest that it will be difficult to replace Cr(VI) in the existing process without replacing the steel cathodes with a more dimensionally stable material.

Overall, the use of Mo(VI) ions shows some promise but also has significant shortcomings with the evolution of oxygen, its poorer buffering, and a current efficiency, which may not be ideal. The elimination of Cr(VI) cannot be guaranteed under the conditions demonstrated in the literature. Evidence of commercial use of this alternative could not be established, and the applicant has no knowledge of any such commercial use.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 36 Table 4-4: Research into sodium molybdate – Li et al, 2007 Parameter Details Year 2007 Source (Li, et al., 2007) – Journal article Associated company/ Aker Kvaerner Chemetics, Canada research organisation Natural Science and Engineering Research Council of Canada (NSERC) for its Industrial R&D Fellowship fund Objective of research or - Identification of a suitable alternative with similar buffering characteristics to invention dichromate and without adverse effect on the electrolytic performance of sodium chlorate production is important to reduce the environmental impact Relevance to the chlorate High; sodium molybdate is examined as a replacement for SD in the chlorate process process

Key changes to current - 8 g/L Na2MoO4 were used chlorate process and - At 22–23 °C, without electrolysis occurring, buffer regions were observed to be notable improvements and pH 5.0–6.0 for molybdate and 5.0-6.5 for dichromate. Dichromate has a better shortcomings buffer “fit” for the chlorate reaction - The current efficiency ranged from 85% to 92% at pH lower than 5.7 and increases to ca. 98% in the pH range 5.75 to 5.95 and drops again above pH 5.95. At lower pH of 5.4, Mo oxides are likely to form at the cathode and adversely affect the current efficiency. At higher pH of 7–10, Mo electrodeposition becomes a main cathodic parasitic reaction with the effect of significantly lowering the current efficiency

- The measured off-gas O2 level was observed to fluctuate between 3.7% and 4.8%. At these values, the current efficiency was only about 91% after 55 hours

of operation and the H2 explosive upper limit was nearly reached (with 4.8% O2). The high off-gas O2 levels clearly show the adverse influence of molybdate on the DSA® anode, because O2 is only generated from the anodic parasitic reactions - In an effort to minimize and control this adverse anodic effect of molybdate on the anode, silica solution was added to the chlorate cell to form

polysilicamolybdate anions; the O2 level in the cell off-gas dropped from 4.8% to 4.3% - Mixed additives based on Mo(VI) and Cr(VI) were also trialled. Although cathode surface potential was lowered substantially at pH 6.7, this pH was outside the buffer region and is not optimum for the chlorate reaction. On the other hand, increased complexity resulting from adding one more compound would counteract the advantage of the reduction of HER overpotential Presence of Cr(VI) in the Handling of Cr(VI): in the absence of SD, molybdenum interferes with the anodic electrolyte reaction and leads to increased evolution of O2 Presence of Cr(VI) in electrolyte: SD not present (but results not favourable)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 37 Table 4-5: Research into sodium molybdate – Rosvall et al, 2010 Parameter Details Year 2010 Source (Rosvall, et al., 2010) – Patent Associated company/ AkzoNobel (EKA) research organisation Objective of research or - Developing a process of for activation of a cathode which reduces the cell invention voltage, while using low amounts of chromium and activating metal(s) - A further object of the invention is to provide a process with high cathodic current efficiency, in which the formation of oxygen is decreased whereby energy losses and the risk of explosions in the cell also are decreased Relevance to the chlorate Significant; the key aim was not to eliminate the presence of Cr(VI) in the electrolyte process Key changes to current - Titanium cathodes were used in the presence of SD in the electrolyte. The chlorate process and addition of SD was at the level of 9 μM Na2Cr2O7•2H2O (ca. 0.003 g/L) notable improvements and - MoO3 was added at variable (low) concentrations ca. 1-10 mg/L. Despite the shortcomings low Mo addition, significant cathode activation was noted but also significant release of oxygen (oxygen evolution of 3.5-3.8%)

- Long term effects were studied with 1 mg/L and 100 mg/L MoO3 added to the electrolyte, this resulted in cathode activation but also release of oxygen which would exceed 3.5% and might even reach >>4% - Experiments made it clear that small amounts of molybdenum species reduces the voltage on the titanium cathode Presence of Cr(VI) in the Handling of Cr(VI): the experiments made did not eliminate the use of SD, but its electrolyte addition was very limited, well below the typical operating conditions of a chlorate cell Presence of Cr(VI) in electrolyte: SD still present but at very low levels

Table 4-6: Research into sodium molybdate – Gustafsson et al, 2012 Parameter Details Year 2012 Source (Gustafsson, 2012) – Thesis (Gustafsson, et al., 2012) – Journal article (Gustafsson, et al., 2012b) – Journal article (Hummelgard, 2012) – Thesis Associated company/ Royal Technical Institute, Stockholm research organisation AkzoNobel (EKA) Objective of research or - The goal was to better understand how molybdate (and REMs) can be used as invention additives to pH neutral electrolytes to activate the Hydrogen Evolution Reaction (HER) Relevance to the chlorate High; the ability of molybdenum to replace SD was considered process

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 38 Table 4-6: Research into sodium molybdate – Gustafsson et al, 2012 Parameter Details Key changes to current - Additions of 4 mM Mo(VI) were made into the electrolyte chlorate process and - Addition of molybdate to neutral and alkaline electrolytes activates the notable improvements and electrolytic HER (on electrode substrates with poor activity for the HER). The shortcomings added molybdate ions are reduced on the cathode forming for example films of oxides or alloys. These films give different electrode substrates a similar activity for HER - The activation for neutral electrolytes was larger with 4 mM molybdate as electrolyte additive than with 100 mM. Large amounts of molybdate appear to be detrimental to the activation. Molybdate also increased the overpotential on the anode due to either adsorption or precipitation of film. Side reactions to the HER can be inhibited by molybdate additive. The additive is more efficient when added to neutral than to alkaline electrolytes. In alkaline electrolytes, films of molybdenum oxides are not stable and thus less efficient at hindering for example hypochlorite reduction. For inhibiting side reactions, molybdate is far less efficient than dichromate - Increased cathode potential, increased anode potential, and increased oxygen level in the presence of high Mo(VI) concentrations give very strong motivation to use a low level of Mo(VI) in the process. Even if the partial current for the side reaction of Mo(VI) reduction appeared to be quite low even for 100 mM Mo(VI), the current efficiency of the HER would probably be even higher if a low Mo(VI) level was used, thus giving another motivation to use a low Mo(VI) level - Comparisons were made of the changes to current efficiency (CE) with Cr and Mo. The addition of 2.7 μM Cr(VI) increased the CE, as measured after 20 minutes of electrolysis, from about 80% to over 94%. This can be compared to 80 mM Mo(VI), which only increased the CE to about 83% despite being present in a concentration about 30,000 times higher. Adding 80 mM Mo(VI) to the Cr(VI)- containing electrolyte did not have a negative effect on the CE, but instead a small positive effect - A low concentration of Mo(VI) alone will not be sufficient to achieve a high current efficiency in the chlorate process. Some other additive therefore also has to be used, for example low levels of Cr(VI). To fully replace Cr(VI) or significantly lower the concentration, a buffer agent such as phosphate will be needed - It will be difficult to replace Cr(VI) in the existing process without replacing the steel cathodes with a more dimensionally stable material Presence of Cr(VI) in the Handling of Cr(VI): a significant reduction in the use of SD could be achieved, but electrolyte other issues would remain (e.g. need to replace cathodes) Presence of Cr(VI) in electrolyte: SD would still be present in low concentrations

Alternative 3: Rare Earth Metal salts

Rare Earth Metal (REM)6 salts have been investigated as an alternative to SD in the chlorate process. Among rare earth metals, yttrium has been given particular attention in relation to the manufacture of sodium chlorate but lanthanum and samarium have also been discussed. The metals are added in the form of their chlorides.

6 Rare earth metals as defined by IUPAC are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium. Scandium and yttrium are considered rare earth elements since they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 39 Key sources of information in the open literature include:

 A thesis and associated journal articles by Nylén and colleagues in 2007-2008, associated with the Royal Technical Institute (KTH) of Stockholm and AkzoNobel (EKA)  A thesis and associated journal articles by Gustafsson and colleagues in 2010-2012, similarly associated with the Royal Technical Institute (KTH) of Stockholm and AkzoNobel (EKA).

A number of key points have been highlighted in this research:

 Effectiveness of REM salts: the addition of Y(III)/La(III)/Sm(III) ions to a suitable (NaCl) electrolyte results in the formation of a hydroxide film on the cathode during hydrogen evolution. According to Nylén and colleagues, a gel-like Y(OH)3 film formed on the iron surface has been found to inhibit the reduction of protons, nitrate ions and of hypochlorite ions. Under certain conditions the film also catalyses hydrogen evolution from the reduction of water.

 Permanence of the REM hydroxide film: the Y(OH)3 film has been found to be sensitive to certain operating parameters; (a) temperature: at 25 °C, additions of 10 mM YCl3, SmCl3 and LaCl3, the REM hydroxide film could easily be seen by the naked eye on the electrode surface after experiments at this temperature, but not after trials at 70°C. It probably dissolved at the higher temperature as the current was switched off; (b) current density and concentration: a low concentration of Y(III) or a high current density when extensive gas evolution disturbs the film formation, hinders the reduction of ions but the film does not activate water reduction. At higher Y(III) concentration (5 M) and lower current densities, the film formed has inhibiting as well as catalytic properties. In addition, when adding Y(III) to chlorate electrolyte at concentrations higher than those experimented with, yttrium precipitates immediately, most likely as Y(OH)3. Higher concentrations may also lead to thicker diffusion layers and concomitant precipitation of Y(OH)3 at a distance from the electrode and no film formation on the surface; (c) pH: at the optimal pH for the chlorate process, Y(III), Sm(III) and La(III) will be very close to precipitation. The exact solubility of REM salts was not determined but REMs started to precipitate at pH 4.8 and therefore it was not possible to perform trials at the normal operating condition of pH 6.5 (Gustafsson, et al., 2010).

 Chromate use and presence: not all of this research has focused specifically on the replacement of chromates from the sodium chlorate process. Nevertheless, the experiments undertaken did not involve the use of SD, hence Cr(VI) would be eliminated from the electrolyte.

Overall, REM salts pose insurmountable problems to their implementation as additives to the chlorate process. At low concentrations, they give a thin cathode film, while at higher concentrations (and lower current densities) the film formed has inhibiting as well as catalytic properties. Given these problems with solubility, temperature and concentration, trivalent metal ions such as REM salts cannot be recommended as an additive to the chlorate process at normal chlorate process conditions.

This alternative is not known to be employed in any commercial application.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 40 Table 4-7: Research into REM salts – Nylén et al, 2007-2008 Parameter Details Year 2007-2008 Source (Nylén, 2008) – Thesis (Nylén, et al., 2008) – Journal article (Nylén, et al., 2007) – Journal article Associated company/ Royal Technical Institute, Stockholm research organisation AkzoNobel (EKA) Objective of research or - The purpose of this work was to identify possible improvements in chlorate invention electrolysis, with the long-term goal of reducing its energy consumption Relevance to the chlorate High, but replacement of Cr(VI) not the main focus of the research process Key changes to current - The addition of Y(III) ions to a 0.5 M NaCl electrolyte resulted in the formation of chlorate process and an yttrium hydroxide film on the cathode during hydrogen evolution. The notable improvements and hydrous, gel-like Y(OH)3 film formed on the iron surface inhibits the reduction of shortcomings protons, nitrate ions and of hypochlorite ions. At certain conditions the film also catalyses hydrogen evolution from the reduction of water. The reactant of the catalysed water reduction is most likely water molecules coordinated to Y(III) within the yttrium hydroxide film - Two forms of film may be distinguished. A film formed at conditions expected to favour a relatively thin film, i.e. a low concentration of Y(III) or a high current density when extensive gas evolution disturbs the film formation, hinders the reduction of ions but the film does not activate water reduction. At higher Y(III) concentrations and lower current densities the film formed has inhibiting as well as catalytic properties. Loss of activation at high current densities may be a problem in electrolysis applications - When adding Y(III) to chlorate electrolyte having a higher ionic strength than the

electrolyte in this work, yttrium precipitates immediately, most likely as Y(OH)3 in the bulk. Another problem might be the mass transport in industrial cells, which has to be good enough for developing a thin diffusion layer of OH-. Thicker

diffusion layers may lead to precipitation of Y(OH)3 at a distance from the electrode and no film formation on the surface

Presence of Cr(VI) in the Handling of Cr(VI): no SD is used in the experimental systems that used YCl3 electrolyte Presence of Cr(VI) in electrolyte: SD is not present (but the Y(OH)3 film does not survive under the typical operating conditions of a chlorate cell)

Table 4-8: Research into REM salts – Gustafsson et al, 2010-2012 Parameter Details Year 2010-2012 Source (Gustafsson, 2012) – Thesis (Gustafsson, et al., 2010) – Journal article Associated company/ Royal Technical Institute, Stockholm research organisation AkzoNobel (EKA) Objective of research or - The goal was to better understand how (molybdate and) trivalent cations can be invention used as additives to pH neutral electrolytes to activate the Hydrogen Evolution Reaction (HER) Relevance to the chlorate Highly relevant; successful results could open a pathway to the elimination of SD process

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 41 Table 4-8: Research into REM salts – Gustafsson et al, 2010-2012 Parameter Details Key changes to current - The addition of Y(III) to a pH neutral electrolyte has been found to catalyse the chlorate process and HER. Addition of Y(III) results in the formation of a Y(OH)3 film at the cathode. notable improvements and Experiments suggest that the efficiency for yttrium hydroxide deposition based shortcomings on the transport of yttrium was about 7%, so the film appears to be destroyed by vigorous gas evolution

- At 25 °C, additions of 10 mM YCl3, SmCl3 and LaCl3, the REM hydroxide film could easily be seen by the naked eye on the electrode surface after experiments at, but not after trials at 70 °C. It was probably dissolved at the higher temperature as the current was switched off - The optimal pH of the chlorate process is close to neutral pH. Y(III), Sm(III) and La(III) will be very close to precipitation around neutral pH. Experiment

observations showed that Y(III) precipitated already at pH 4.8 in 550 g/L NaClO3 at 70 °C, which means that the Y(III) will be in precipitated form at pH 6.5. It is possible that the trivalent cations also form precipitations with anions in the electrolyte. In the chlorate process, the sodium chlorate is separated from the electrolyte with crystallization at alkaline pH. If added to an industrial chlorate electrolysis process, the trivalent cations would precipitate in this step and potentially contaminate the chlorate product - High chloride concentrations form complexes with Y(III) and probably also with other trivalent metal ions and thus decrease the activation of the HER. High temperatures also decrease the degree of activation achieved by addition of trivalent cations - Given these problems with solubility, temperature and chlorides, trivalent metal ions cannot be recommended as an additive to the chlorate process. Trivalent cations can be a promising additive to activate the HER at room temperature and chloride levels below 0.5 M Presence of Cr(VI) in the Handling of Cr(VI): the experiments did not involve SD; however, this is of limited electrolyte relevance given the above shortcomings of REMs Presence of Cr(VI) in electrolyte: in theory, absent, but not relevant due to technical shortcomings

Alternative technologies for the sodium chlorate process

Introduction to alternative electrode materials and coatings

Section 2.1.2 describes that SD is added to the electrolyte to form a thin film of chromium hydroxide on the cathode, and the film electrochemically hinders the reduction of the hypochlorite and chlorate and thus improves the current efficiency of the chlorate process. It also affects the rate of the hydrogen evolution reaction (HER). There has been research that has specifically aimed at improving current efficiency and/or control over the hypochlorite reaction by means of developing novel coatings for electrodes or novel electrode materials. Relevant technologies suggested in the literature include:

 Coatings based (primarily) on  Molybdenum  Ruthenium  Zirconium  Electrodes based on  Ruthenium-titanium alloys  Ruthenium-based, titanium-free alloys.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 42 A summary of the available literature information regarding to alternative electrode materials and coatings is presented below.

Alternative 4: Molybdenum-based cathode coatings

The use of molybdenum-based coatings has been investigated as an alternative to SD in the chlorate process, although some of the relevant research was not specifically aimed at eliminating the use of SD. The material deposited on the cathode in one patent was made out of a bath comprising FeCI3, Na2MoO4, NaHCO3 and Na2P2O7 or RuCl3 and MoCl3. Another patent has also been filed on cathodes coated with Ni-Mo but that does not address the use of SD in chlorate cells.

Key sources of information in the open literature include:

 A patent by Krstajic et al in 2007, associated with Industrie De Nora S.p.A., a leading electrode supplier  A patent by Rosvall et al in 2009, associated with AkzoNobel (EKA).

A number of key points have been highlighted in this research:

 Current efficiency and oxygen evolution: molybdenum-based coatings show some promise as regards the achieved oxygen evolution, cell voltage and cathodic current efficiency

 pH buffering: to ensure adequate buffering of pH at the desired level (achieve and initial pH 6.4), sodium acid phosphates (3 g/L) need to be added to the electrolyte

 Chromate use and presence: in the Krstajic et al patent, a low addition of SD (0.1 g/L) was required to ensure acceptable (equivalent) current efficiency. In the Rosvall et al patent, SD was used at typical concentrations (4.4 g/L).

Overall, the use of Mo-based cathode coatings shows some promise but may need to be accompanied by the addition of phosphate to ensure adequate pH buffering which can be problematic, as discussed in Section 5. The elimination of Cr(VI) cannot be guaranteed under the conditions demonstrated in the literature but a (significant) reduction in the concentration of SD to the electrolyte seems plausible. Evidence of commercial use of this alternative could not be established, and the applicant has no knowledge of any such commercial use.

Table 4-9: Research into molybdenum-based cathode coatings – Krstajic et al, 2007 Parameter Details Year 2007 Source (Krstajic, et al., 2007) – Patent Associated company/ Industrie De Nora S.p.A. research organisation Objective of research or - The patent relates to a process for the industrial electrolytic production of invention sodium chlorate, characterised by a high yield and a high electrical efficiency - The patent is aimed at developing a system for sodium chlorate production with low energy consumption making use of a nil or extremely limited amount of chromium compounds Relevance to the chlorate High relevance; elimination of SD was among the objectives of the patent process

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 43 Table 4-9: Research into molybdenum-based cathode coatings – Krstajic et al, 2007 Parameter Details Key changes to current - Activation of the carbon steel cathodes was achieved through a bath prepared by chlorate process and dissolution of 9 g/L FeCI3, 40 g/L Na2MoO4, 75 g/L NaHCO3 and 45 g/L Na2P2O7 in notable improvements and distilled water, and the deposition was carried out at a constant current density shortcomings of 100 mA/cm2 at a temperature of 60°C, making use of a platinum fine mesh as the counterelectrode, under stirring. The deposition was protracted until obtaining a 20 micrometre thick alloy comprised of 47% by weight molybdenum and 53% by weight iron, as detected by a subsequent X-ray energy dispersion spectroscopy test - The voltage and energy efficiency of the cells with and without Mo-activated electrodes are shown below

Electrolyte Conditions Cell with activated Cell with non- cathodes activated cathodes 300 g/L NaCI pH = 6.41 Voltage: 3.01-3.02 Voltage: 3.14-3.17 3 g/L SD 2.5 kA/m2 Efficiency: 98% Efficiency: 97% 61°C 300 g/L NaCI pH = 6.40 Voltage: 2.86-2.87 Voltage: 3.08-3.12 3 g/L sodium acid 2.5 kA/m2 Efficiency: 97% Efficiency: 91% phosphates (Na2HPO4 and 60-61°C NaH2PO4) 0.1 g/L SD 300 g/L NaCI pH = 6.41 Voltage: 2.50-2.53 Voltage: 3.16-3.17 3 g/L sodium acid 2.5 kA/m2 Efficiency: 94% Efficiency: 72% phosphates (Na2HPO4 and 61°C NaH2PO4) Presence of Cr(VI) in the Handling of Cr(VI): one of the embodiments does not include the use of SD, but electrolyte results in lower current efficiency and lower voltage Presence of Cr(VI) in electrolyte: an option was investigated where SD was not present in the electrolyte Notes: Another patent (Krstajic, et al., 2010) has also been filed on cathodes coated with Ni- Mo but that does not address the use of SD in chlorate cells

Table 4-10: Research into molybdenum-based cathode coatings – Rosvall et al, 2009 Parameter Details Year 2009 Source (Rosvall, et al., 2009) Associated company/ AkzoNobel (EKA) research organisation Objective of research or - The patent relates to the process of preparing an electrode for the production of invention alkali metal chlorate and improving the electrolytic process. Emphasis is given on providing a cell in which a bipolar electrode or hybrids of bipolar and monopolar electrodes are mounted and to investigate a cell in which the polarity of the electrodes can be reversed such that the electrodes successively can work as anode and cathode within a given period of time. - A further object of the invention is to provide an electrode improving the cathodic current efficiency when in operation in an electrolytic cell, particularly while reducing the cell voltage - A further object of the invention is to provide electrodes which may lower the metal loading of precious metals on an electrode substrate while substantially maintaining the performance of commercial electrodes

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 44 Table 4-10: Research into molybdenum-based cathode coatings – Rosvall et al, 2009 Parameter Details Relevance to the chlorate High; but invention not aimed at replacing or reducing the use of SD; SD was used in process the experiments Key changes to current - Experiments were based on an electrolyte containing 120 g/L NaCI, 580 g/L chlorate process and NaCIO3, and 4.4 g/L SD notable improvements and - RuCl3 and MoCl3 were used to deposit a layer on a Ti-based electrode shortcomings - The results of oxygen evolution, cell voltage and cathodic current efficiency are shown below - In this experiment, the current efficiency of the titanium cathodes coated with molybdenum oxide and were superior to the current efficiency of the baseline electrodes (PSC 120). For the molybdenum oxide-coated cathode, a decrease in oxygen formation was also observed

Oxygen (%) CCE (%) Cell voltage (V) Comment 2.3 95 2.87 Baseline 2.3 96 2.85 After stop 2.0 100 3.14 Mo/Ru-oxide on Ti (Grade 1) 2.1 99 3.18 After stop Presence of Cr(VI) in the Handling of Cr(VI): SD was used as normal electrolyte Presence of Cr(VI) in electrolyte: SD was present at typical operating levels

Alternative 5: Ruthenium-based cathode coatings

The use of ruthenium-based coatings has been investigated in the context of the chlorate process, however, the research has so far focused on the development of new cathode coatings that would allow more efficient operation of the cell and reduced energy consumption, rather than the reduction or elimination of the use of SD in industrial chlorate cells. The material deposited on the cathode is RuO2, although a patent has provided a comparison of the RuO2 coatings to Ru/W oxide and Ru/Mo coatings (on Ti3SiC2 ceramic material).

Key sources of information in the open literature include:

 A thesis and journal articles by Cornell and colleagues, associated with the Royal Institute of Technology (KTH) in Stockholm and AkzoNobel (EKA)  The aforementioned 2009 Rosvall et al patent, associated with AkzoNobel (EKA).

A number of key points have been highlighted in this research:

 Oxygen evolution: when RuO2 coatings were used in experiments (Ti0.7Ru0.3O2) in the presence of chromates, oxygen evolution somewhat increased (as shown by Rosvall et al). On the other hand, when in the presence of molybdenum or tungsten, such an issue did not arise

 Current efficiency: RuO2 coatings on titanium electrodes have a current efficiency poorer than under typical SD use. However, current efficiency may improve when mixtures of other oxides (TiO2, MoO2, WO2) are used alongside RuO2

 Stability concerns: thicker RuO2 coatings may be eroded by the vigorous gas evolution and improved stability is necessary before RuO2-based activated cathodes can be used industrially

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 45  Chromate use and presence: hypochlorite and chlorate ions are reduced on RuO2 in the absence of the chromium hydroxide film, under typical conditions (70 °C, 3 kA/m2). An addition of SD to the chlorate electrolyte is necessary in order to keep a high current efficiency on the cathode. The level of SD addition would appear to be similar to that of current practices (3-6.5 g/L).

Overall, the conclusion so far has been that the use of SD cannot be eliminated as the RuO2 coatings lead to the reduction of chlorate at fast rates. There is no available evidence that the dosage of SD can be reduced compared to the current state of the art process. Evidence of commercial use of this alternative could not be established, and the applicant has no knowledge of any such commercial use.

Table 4-11: Research into ruthenium-based cathode coatings –Cornell et al, 1993-2006 Parameter Details Year 1993, 2002, 2006 Source (Cornell & Simonsson, 1993) – Journal article (Cornell, 2002) – Thesis (Nylén & Cornell, 2006) – Journal article Associated company/ AkzoNobel (EKA) research organisation Royal Institute of Technology, Stockholm Objective of research or - Investigation of Ru-based DSA® anodes and how the concentrations of chloride, invention chlorate, chromate, as well as pH, mass-transport and temperature affect the anode potential

- Investigation of RuO2 coatings on activated cathodes and their role in reducing energy consumption - Investigation of the role of the Cr(III) hydroxide film around the cathode Relevance to the use and Limited; the research was not focused on the replacement of Cr(Vi) but did replacement of Cr(VI) in the investigate its role in the electrolyte and around the anodes chlorate process Key differences to current - The rate of the hydrogen evolution reaction in the chlorate process strongly chlorate process and depends on the electrode material. Thermally prepared RuO2 coatings are notable improvements and relatively active due to a favourable reaction mechanism in combination with shortcomings large real surface areas. At the current density of 3 kA/m2, typical for industrial electrolysis, the overvoltage for hydrogen evolution is about 300 mV lower on

RuO2 than on corroded iron - In chlorate electrolyte, the 100 % RuO2 electrodes are more active than the DSA®s, and the overpotential depends on the coating thickness - In chlorate electrolyte, the effect of the film on hydrogen evolution on an iron or

a RuO2 cathode is difficult to estimate, since the current in a chromate-free solution is a sum of currents from hydrogen evolution, chlorate reduction and hypochlorite reduction

- The thicker RuO2 coatings prepared in the laboratory were eroded by the vigorous gas evolution and improved stability is necessary before RuO2-based activated cathodes can be used industrially

- A thin film of Cr(III)hydroxide is formed on the RuO2 cathode in the chlorate process. The film efficiently hinders the reduction of hypochlorite and chlorate

- Hypochlorite and chlorate ions are reduced on RuO2 in the absence of the chromium hydroxide film, the chlorate reduction reaction being relatively fast on

RuO2 and by far the dominating reaction in chromate-free chlorate electrolyte at 70 °C, 3 kA/m2. Chlorate reduction on iron is faster if the electrode is corroded. In the chlorate process, chlorate reduction is activation controlled. Therefore, a

mass transport barrier, as an alternative to dichromate addition on the RuO2 cathode, will not efficiently hinder chlorate reduction. An addition of SD to chlorate electrolyte is necessary in order to keep a high current efficiency on the

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 46 Table 4-11: Research into ruthenium-based cathode coatings –Cornell et al, 1993-2006 Parameter Details cathode

- Catalytic electrode materials, such as RuO2, were deactivated after dichromate addition whereas the film activated inferior electrocatalysts, such as gold

- RuO2 showed relatively good resistance to iron poisoning and other electrolyte impurities Presence of Cr(VI) in the Handling of Cr(VI): the addition of Cr(VI) was necessary in order to suppress parasitic electrolyte reactions (an addition of 0.015M of Na2CrO4 is described (ca. 2-3g/L)) Presence of Cr(VI) in electrolyte: Cr(VI) still present, probably at similar concentrations to current practices

Table 4-12: Research into ruthenium-based cathode coatings – Rosvall et al, 2009 Parameter Details Year 2009 Source (Rosvall, et al., 2009) – Patent Associated company/ AkzoNobel (EKA) research organisation Objective of research or - Development of an electrode which has improved performance in an electrolytic invention cell, notably improving the cathodic current efficiency when in operation in an electrolytic cell, particularly while reducing the cell voltage, showing reduced thickness resulting in material savings and optimisation enabling an increased number of 5 electrodes arranged in the same cell space whereby production may be increased without up-scaling an existing plant - Development of an electrode that does not corrode whereby sludge which could be deposited on the anodes is not formed - Development of an electrode that is resistant to hydrogen evolving conditions and reducing conditions in alkaline environment and at least shorter exposures in oxidative environment - Development of an electrolytic cell and a process for the production of alkali metal chlorate. It was particularly desired to provide such a cell in which the formation of oxygen and thereby danger of explosions is decreased while the operating conditions are facilitated - Development of an electrolytic cell in which a bipolar electrode or hybrids of bipolar and monopolar electrodes are mounted - Development of an electrolytic cell in which the polarity of the electrodes can be reversed such that the electrodes successively can work as anode and cathode within a given period of time Relevance to the chlorate Highly relevant to the chlorate process, but not relevant to the removal of SD from process the process/electrolyte Key changes to current A series of experiments were conducted under different configurations the results of chlorate process and which are summarised below. notable improvements and shortcomings Ru-based Cathode SD Cathodic Cell Oxygen* cathode coating material current voltage* efficiency* No coating Ti No SD 92% 3.30 V 3.7% 96% AS No coating Mild steel No SD 86% 3.01 V 4.2% Failed AS N/A AS

No coating Ti3SC2 No SD 100% 3.24 V 3.9% No coating Ti 4.4 g/L 99% 3.37 V 2.3% Failed AS No coating Mild steel 4.4 g/L 97% 3.00 V 2.2%

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 47 Table 4-12: Research into ruthenium-based cathode coatings – Rosvall et al, 2009 Parameter Details 90% AS 3.01 V AS 2.4% AS

No coating Ti3SC2 4.4 g/L 100% 3.28 V 2.3% 3.23 V AS

No coating, Ti3SC2 4.4 g/L 100% 3.35 V 1.8% machined 3.33 V AS

No coating, Ti3SC2 4.4 g/L 100% 3.29 V 2.1% sandblasted 3.28 V AS

No coating, Ti3SC2 4.4 g/L 100% 3.36 V 1.7% polished 3.34 V AS

Ti0.7Ru0.3O2 Ti 4.4 g/L 95% 2.87 V 2.3% 96% AS 2.85 V AS Mo/Ru oxide Ti 4.4 g/L 100% 3.14 V 2.0% 99% AS 3.18 V AS 2.1% AS W/Ru oxide Ti 4.4 g/L 99% 3,22 V 2.2% 3.27 V AS st nd rd 1 , 2 , 3 layer Ti3SC2 4.4 g/L 100% 2.85 V 2.1% Ru0.83Mo0.17O2 2.89 V AS st 1 Ru0.3Ti0.7O2; Ti3SC2 4.4 g/L 100% 2.93 V 2.2% 2nd and 3rd layer 2.94 V AS Ru0.83Mo0.17O2 st nd rd 1 2 and 3 Ti3SC2 4.4 g/L 95% 2.80 V 2.8% RuO2 (no result 2.93 V AS AS) * AS = after stop Presence of Cr(VI) in the Handling of Cr(VI): SD needs to be used at concentrations within the typical electrolyte operating range Presence of Cr(VI) in electrolyte: Cr(VI) still present in the electrolyte

Notably, older research focused on the potential benefits of replacing iron cathodes with titanium ones coated in oxides such as RuO2 and the results were encouraging (see the table that follows), but the state of the art described in the relevant patent is outdated compared to current development and the invention based on RuO2 and other metal oxides has not developed into an industrially-proven alternative.

Table 4-13: Research into ruthenium-based cathode coatings – Yoshida et al, 1981 Parameter Details Year 1981 Source (Yoshida, et al., 1981) – Patent Associated company/ Hodogaya Chemical Co., Ltd research organisation Objective of research or - Development of an activated cathode which is capable of preventing a cathode invention current loss due to the reducing reaction in the aqueous solution electrolysis, has a low overvoltage, a high corrosion resistance and a high mechanical strength and is easy to handle - Prevention of the contamination of product and effluent by metal salt added to the electrolytic bath in the aqueous solution electrolysis Relevance to the chlorate High relevance; reduction of use of chromate is presented as one of the benefits of process the invention

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 48 Table 4-13: Research into ruthenium-based cathode coatings – Yoshida et al, 1981 Parameter Details Key changes to current The patent refers to an activated cathode which comprises: chlorate process and - A base plate, e.g. titanium notable improvements and - A metal oxide layer formed on the surface of the base plate, e.g. ruthenium, shortcomings rhodium, palladium, osmium, iridium and platinum, the most efficient appearing to be ruthenium - An oxide of one or more metal elements selected from the group consisting of calcium, magnesium, strontium, barium and zinc in the group II and chromium, molybdenum, tungsten, selenium and tellurium in the group VI - Titanium cathodes coated with Ru or Rh were accompanied of considerable cathode current loss in the absence of chromate - Titanium cathodes with Ru+Rh coatings and the addition of metal oxides such as

CaO, MgO, BaO, SrO and Cr2O3 showed cathode current loss lower than iron cathodes in the presence of 2 g/L SD Presence of Cr(VI) in the Handling of Cr(VI): the use of 2 g/L SD could be eliminated with the use of a electrolyte combination of metal oxides on a titanium base. However, according to (Lindbergh & Simonsson, 1991), these cathodes only allow the kinetics of the hypochlorite ion reduction reaction to be slowed down but do not allow the reaction to be eliminated (Andolfatto & Delmas, 2002) Presence of Cr(VI) in electrolyte: Cr(VI) would still be present in the electrolyte to ensure the efficiency of the process

Alternative 6: Zirconium-based cathode coatings

The use of zirconium-based coatings has been investigated in the context of the chlorate process; however, the relevant research may not have aimed at the reduction or elimination of the use of SD in industrial chlorate cells. The material deposited on the cathode is ZrO2 (the layer can be applied on a zirconium surface by thermal decomposition of a Zr-containing solution), although patents describe external layers of ZrTiO4 accompanied by RuO2 (and optionally by ZrO2 and/or TiO2) and ZrO2 modified with Y2O3 on a zirconium plate.

Key sources of information in the open literature include:

 A journal article by Herlitz et al in 2001, associated with the Royal Institute of Technology in Stockholm  A patent by Andolfatto & Delmas in 2002, associated with Atofina  A patent by Brown et al in 2010, associated with Industrie De Nora, S.p.A.

A number of key points have been highlighted in this research:

 Suppression of parasitic reactions: ZrO2 reduces the rate of hypochlorite reduction, but does not entirely inhibit it. Combinations of Zr with Ti and/or Ru are required for a better suppression

 Cathodic current efficiency: when ZrO2 modified with Y2O3 was deposited on a zirconium plate, a cathodic efficiency of up to ca. 91% (after 104 days) was recorded. However, this was in a hypochlorite cell without direct linkages to the use of SD for the manufacture of chlorate, therefore, the applicability of the described system to the chlorate cell is unclear

 Chromate use and presence: no chromate was used in the experiments described in the patents above.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 49 Overall, the conclusion so far has been that Zr-based coatings may be used in the absence of chromate, but the achieved cathodic current efficiency may not necessarily be as high as in a typical chlorate cell in the presence of a cathodic chromium hydroxide film. It is understood that efforts have been made to implement a Zr-coated cathode on an industrial scale, but this was unsuccessful and led to the abandonment of the relevant research.

Table 4-14: Research into zirconium-based cathode coatings – Herlitz, 2001 Parameter Details Year 2001 Source (Herlitz, 2001) – Patent Associated company/ Royal Institute of Technology, Stockholm research organisation Objective of research or To clarify the effect of oxidised zirconium on parasitic cathodic reactions in the invention chlorate process, electrochemical studies were carried out at laboratory scale. The techniques used were cyclic voltammetry and recording of polarisation curves Relevance to the chlorate Significantly relevant; oxidised zirconium was considered as a means for suppressing process the hypochlorite parasitic reaction, but not as a direct replacement additive for SD Key changes to current - Oxidised zirconium cathodes reduce the rate of hypochlorite reduction, although chlorate process and not entirely inhibiting it, which is mainly related to a lowered active area due to notable improvements and the porous layer of zirconium dioxide. shortcomings - The oxidised samples are partly passivated, giving high overvoltages for the hydrogen evolution reaction. These overvoltages gradually decrease during cathodic polarisation due to the simultaneous reduction of the zirconium oxide - Studies of the selectivity indicate that hypochlorite reduction occurs on the oxidised zirconium cathodes to a high extent, the thermal oxide being somewhat better - It is concluded that zirconium oxide is not a suitable cathode material for the sodium chlorate process Presence of Cr(VI) in the Not relevant, the alternative has not proven technically feasible electrolyte

Table 4-15: Research into zirconium-based cathode coatings – Andolfatto & Delmas, 2002 Parameter Details Year 2002 Source (Andolfatto & Delmas, 2002) – Patent Associated company/ Atofina research organisation Objective of research or Development of a cathode which allows the chlorate of an alkali metal to be invention electrolytically synthesised with a high coulombic yield and in the absence of SD Relevance to the chlorate Highly relevant; Zr/Ru coatings were considered in order to eliminate the parasitic process hypochlorite reduction and eliminate the need for SD Key changes to current - This specific cathode comprises a titanium substrate with an external layer of chlorate process and ZrTiO4 accompanied by RuO2 and optionally by ZrO2 and/or TiO2 notable improvements and - Depending on the ration Zr/Ti and Ru/(Zr+Ti+Ru), different suppression of the shortcomings hypochlorite reduction can be achieved in the absence of SD - For a ratio Zr/Ti equal to 1 and Ru/(Zr+Ti+Ru) equal to 0.001, the new electrode would appear to limit the hypochlorite reduction to the same extent as SD on a mild-steel electrode Presence of Cr(VI) in the Handling of Cr(VI): SD was eliminated in the examples shown in the patent; some electrolyte embodiments achieved results similar to those obtained with SD and steel cathodes Presence of Cr(VI) in electrolyte: Cr(VI) would not be present in the electrolyte

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 50 Table 4-16: Research into zirconium-based cathode coatings – Brown et al, 2010 Parameter Details Year 2010 Source (Brown, et al., 2010) – Patent Associated company/ Industrie De Nora, S.p.A. research organisation Objective of research or A cathodic member for electrochemical cells used in hypochlorite production invention comprises a zirconium plate coated with a zirconium oxide layer, which is particularly suitable for minimising the decomposition of the hypochlorite product while ensuring a prolonged lifetime. The coated zirconium plate can be used as the cathodic plate in a monopolar cell, or can be welded to a titanium plate for use in a bipolar configuration Relevance to the chlorate The invention relates to electrochemical cells for the production of hypochlorite process solutions; although reference is made to chlorate cells, the applicability of the invention is uncertain. It is mentioned that the addition of SD in hypochlorite systems for water disinfection is not relevant, as the presence of chromium is not acceptable

Key changes to current - Although ZrO2 is very stable to the caustic environment established on cathode chlorate process and surfaces, the cathodically-evolved hydrogen tends to detach the protective layer notable improvements and from the titanium body in a short time shortcomings - The invention comprises a zirconium oxide coated zirconium plate for use as a cathode member in an electrolytic cell for the production of hypochlorite - While titanium has always been the valve metal of choice for valve metal-based cathode plates of hypochlorite cells due to its lower cost and its superior

resistance against corrosion, it has been found that ZrO2 layers grown on zirconium surfaces are much more resistant to detachment induced by cathodically-evolved hydrogen compared to similar layers grown on titanium

- In thermal-sprayed layers, ZrO2 can be mixed with other suitable oxides to modify the structure of the layer, for instance to obtain an adequate porosity.

Zirconium oxide modified with a small amount of Y2O3, usually less than 10% molar is sometimes used on titanium plates and proves beneficial also on zirconium plates.

The results on current efficiency using different versions of Zr plates are below.

Cathode material Initial CE after Cathode material Initial CE after CE 104 CE 104 days days

Zr plate with ZrO2 93.0% 88.4% Ti plate uncoated 78.4% 72.5% deposited with thermal decomposition of Zr acetate Zr plate with 87.2% 91.3% Ti plate with 89.3% Failed plasma-spraying of plasma-spraying of after 44 ZrO2 modified with ZrO2 modified with days 8% of Y2O3 8% of Y2O3 Zr plate with 93.4% 90.0% Pt plate with 91.8% Failed thermally grown plasma-spraying of after 44 ZrO2 layer ZrO2 modified with days 8% of Y2O3 Bipolar Ti/Zr 88.5-92.7% cathode with 4 coats of Ru/Ir/Ti Presence of Cr(VI) in the Not relevant to SD electrolyte

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 51 Alternative 7: Ruthenium alloy cathodes

The use of ruthenium-titanium-based alloys as cathode materials has been investigated in the past as a means for reducing energy consumption, rather than with the aim of eliminating SD from the electrolyte.

Key sources of information in the open literature include patents and journal articles associated with Canadian interests, particularly the Canadian Institut de recherche d'Hydro-Québec, as shown in Table 4-17 and Table 4-18.

A number of key points have been highlighted in this research:

 Hydrogen overpotential reduction: Ru-Ti alloy cathodes significantly reduce the hydrogen overpotential by 300 mV more than the steel cathodes

 Suppression of hypochlorite decomposition and oxygen evolution: the speed of hypochlorite - - decomposition (2 ClO  2 Cl +O2) was found to be low, even lower than the speed measured on the steel electrodes, which meant that there was very little molecular oxygen released

 Chromate use and presence: the use of SD is uncertain. The patents and journal article published in the 1990s suggest that SD may not be used but the alloy may comprise up to 50% chromium. On the other hand, the 2006 patent by Schulz et al refers to an aluminium- containing nanocrystalline alloy which, apparently, might be used in the presence of a cathodic Cr(OH)3 film.

Overall, these ruthenium-titanium alloys show some good performance in terms of current efficiency and suppression of parasitic reactions, however, they seem unable to guarantee the elimination of the use of SD or the presence of chromium in the electrolyte. Evidence of commercial use of this alternative could not be established, and the applicant has no knowledge of any such commercial use.

Table 4-17: Research into ruthenium/titanium alloy cathodes – Van Neste al al, 1996, Boily et al, 1997, Schulz et al, 1997 & 2006 Parameter Details Year 1996, 1997, 2006 Source (Van Neste, et al., 1996) –Journal article (Boily, et al., 1997) – Patent (Schulz, et al., 1997) – Patent (Schulz, et al., 2006) – Patent Associated company/ Institut de recherche d'Hydro-Québec research organisation EKA Chimie Canada Objective of research or - The present invention relates to new nanocrystalline alloys containing Ti, Ru, Fe invention and O. The invention also relates to a process of preparation of these new alloys - The patent was the result of a research carried out to improve the electric efficiency of the cells used for the electrochemical synthesis of sodium chlorate, whose consumption is very high (about 50 to 100 MW per plant) Relevance to the chlorate High, but no mention to the presence of SD in the electrolyte is made process Key changes to current - According to the 1997 patents, a method of producing sodium chlorate by chlorate process and electrochemical synthesis in an electrolysis cell having cathodes made of a notable improvements and complex alloy according to of the formula: shortcomings Ti30+x Ru15+y Fe25+z O3u+t Mu

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 52 Table 4-17: Research into ruthenium/titanium alloy cathodes – Van Neste al al, 1996, Boily et al, 1997, Schulz et al, 1997 & 2006 Parameter Details where M is preferably chromium and x is between -5 and +5 y is between -5 and +5 z is between -5 and +5 t is between -28 and +5 u is between 0 and +10, x+y+z+t+u=0 - The alloy may comprise up to 50% at chromium. This addition could reduce substantially or even eliminate the use of SD - When measured under a current of density of 250 mA/cm2 at 70 °C in an electrolyte cell, the overpotential of hydrogen was approximately 300 mV lower than the one of the steel cathodes. The latter have an overpotentials of hydrogen equal to approximately 900 mV while the cathodes made from the alloys according to the invention have an overpotential of hydrogen equal to about 600 mV. When multiplied by the number of cathodes and the number of cells in a sodium chlorate production plant, this reduction in the overpotential of hydrogen represents a net gain of electric energy of more than 10% - The speed of decomposition of the hypochlorite in contact with the material forming the cathodes was very low, even lower than the speed measured on the steel electrodes, which meant that there was very little molecular oxygen released. This reduced even more the risks of simultaneous release of molecular hydrogen and oxygen with all the inherent risks of explosion that such implies - The cathodes made from the alloy can be welded directly on titanium anodes

- The 2006 patent refers to an alloy of the formula Ti2+t(Ru(1-x_Al(1+x))(1-u/2)MuTy, wherein: t is a number preferably between -0.5 and +0.5; x is a number preferably between +0.5 and +0.9; u is a number preferably less than 0.25; y is a number preferably equal to 2; M represents one or more elements selected among Ag, Pd, Rh, Fe, Cr and V, the elements being preferably, Ag, Pd or Rh; and T represents one or more elements selected among O, B, S, C, N, Si, P and H, the elements being preferably oxygen. Said alloy is preferably in nanocrystalline form - This latter patent suggests that suitable alloys should not interfere with the

Cr(OH)3 film on the cathode, suggesting that SD may still be used Presence of Cr(VI) in the Handling of Cr(VI): it is implied that SD may not need to be used, but the cathode electrolyte would contain significant levels of chromium in the older Schulz et al patent. For the second patent, Cr may comprise up to 50% of the alloy Presence of Cr(VI) in electrolyte: uncertain

Table 4-18: Research into ruthenium/titanium alloy cathodes – Gebert et al, 2000 Parameter Details Year 2000 Source (Gebert, et al., 2000) – Journal article Associated company/ École Polytechnique de Montréal research organisation IFW Dresden Institut de recherche d'Hydro-Québec Objective of research or Development of cathodes that wil allow a reduction to energy consumption invention Relevance to the chlorate Uncertain; cathodes for chlorate electrolysis are discussed but it is uncertain if this is process in light of the use of Cr(VI) in the electrolyte Key changes to current - Cathodes for chlorate electrolysis were prepared by mixing nanocrystalline Ti– chlorate process and Ru–Fe–O catalyst powder with small amounts of Teflon and subsequent hot

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 53 Table 4-18: Research into ruthenium/titanium alloy cathodes – Gebert et al, 2000 Parameter Details notable improvements and pressing on a carbon–Teflon sub-layer shortcomings - The behaviour of electrodes with catalyst loadings from 300 mg/cm2 reduced to 10 mg/cm2 was investigated in chlorate electrolyte with pH 6.5 and in part, for comparison, in 1 M sodium hydroxide solution at 70 °C - The as-milled catalyst powder electrodes showed a high activity for the HER in chlorate electrolyte particularly expressed in low overpotentials of about 580 mV at −250 mA/cm2 for catalyst loadings down to 20 mg/cm2 and high double layer capacitances in the freshly prepared state. These electrodes show increased activity at low polarisation. The long-term stability during electrolysis was also analysed Presence of Cr(VI) in the Handling of Cr(VI): uncertain electrolyte Presence of Cr(VI) in electrolyte: uncertain

Later research by scientists at the Canadian Institut de recherche d'Hydro-Québec focused on a new family of electrocatalytic materials consisting of an iron aluminide (Fe3Al) alloy doped with ruthenium and with the potential addition of tantalum. Experiments with these new alloys still require the use of SD, the addition of which is described at 3 g/L.

These alloys have not yet found commercial use. On the Institut de recherche d'Hydro-Québec’s website an invitation for Expressions of Interest was available in early 2014 aimed at the attribution of a worldwide exclusive license for the valorisation of the technology based on the Ru-alloys, a technology entitled “Chlorate Efficient Cathode Technology”. The call for expressions of interest has been issued to selected parties that have interests in sodium chlorate production technologies. The Canadian Institute claims that, “the new cathodes can provide up to approximately 10% of energy savings to the sodium chlorate production process depending on operating conditions. These electrocatalytic electrodes which are highly resistant to corrosion are dimensionally stable and lead to very low levels of iron impurities as a result of their utilization”7.

Overall, these alloys cannot guarantee the elimination of SD use or the presence of chromium in the electrolyte and have not yet found commercial use.

Table 4-19: Research into ruthenium alloy cathodes – Schulz & Savoie, 2009-2013 Parameter Details Year 2009, 2010, 2013 Source (Schulz & Savoie, 2009) – Journal article (Schulz & Savoie, 2010) – Journal article (Schulz & Savoie, 2010b) – Patent (Schulz & Savoie, 2013) – Patent Associated company/ Institut de recherche d'Hydro-Québec research organisation Objective of research or The journal articles and patents discuss a new family of electrocatalytic materials invention consisting of an iron aluminide (Fe3Al) alloy doped with a catalytic element such as ruthenium. High energy ball milling is used to prepare these new metastable nanocrystalline alloys and their cathodic overvoltages for the hydrogen evolution reaction in a chlorate electrolyte are about 400 mV lower than that of iron cathodes

7 Information on the Call for Expressions of Interest is available at http://www.hydroquebec.com/innovation/en/partenariats.html (accessed on 11 April 2014).

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 54 Table 4-19: Research into ruthenium alloy cathodes – Schulz & Savoie, 2009-2013 Parameter Details Relevance to the chlorate Substantially relevant, but not aimed at replacing SD process Key changes to current - The catalysed iron aluminide nanocrystalline powders were prepared by high chlorate process and energy ball milling starting from mixtures of Fe3Al and Ru powders notable improvements and - The electrochemical set-up consisted of a two-compartment cell with a capacity shortcomings of about one litre. The counter electrode was a DSA anode. The electrolyte was

a synthetic standard chlorate electrolyte containing 550 g/L of NaClO3, 110 g/L of NaCl, 3 g/L of SD and 1 g/L of NaClO. The pH was regularly adjusted at 6.5 using NaOH or HCl. - The electrodes made of compacted ball milled powders have overpotential values for the HER at 250 mA/cm2 in a chlorate electrolyte about 400 mV lower than that of iron cathodes - The 2010 patent does not describe the use of SD, but this is implied as it mentions “One sees on this figure the characteristic peaks of Fe, Al, and Ru but also of Na and Cr coming from the electrolyte”. - The 2013 patent discusses the corrosion resistance of the alloys described earlier. This was found to be good at pH 6.5 but poor in acidic conditions (standard industrial practises use acid wash from time to time to clean electrochemical cells and electrodes). To solve this problem, the inventors discovered that the addition of a small amount of Ta to these materials could make these new alloys not only highly resistant to corrosion in chlorate electrolyte but also in acidic (HCl) solutions without losing performance regarding the electrochemical synthesis of sodium chlorate. The alloys of

interest are Fe3-xAl1+xMyTzTat (x is between -1 and +1, y is between 0 and +1, z is a between 0 and +1 and t is between 0 and +1). The electrolyte again contains 3 g/L SD Presence of Cr(VI) in the Handling of Cr(VI): SD is still added to the electrolyte at typical concentrations electrolyte Presence of Cr(VI) in electrolyte: SD is still present in the electrolyte

Other technologies

Alternative 8: Two-compartment electrolytic systems

Other technologies that may be considered alternatives to chromate-based solutions go beyond the electrode level. These could include variations of two-compartment cells (for example, membrane- type ‘chlor-alkali’ cells).

The key sources of information regarding this alternative are a number of patents. These include:

 A patent by Cook in 1975, associated with Hooker Chemicals Plastics Corp  A patent by Millet in 1990, associated with Atochem (now Arkema)  A patent by Delmas & Ravier in 1993, associated with ELF Atochem (now Arkema)

The chlor-alkali process is a process related to a chlorate cell but with some important differences. The electrodes in a chlorate cell are in one compartment, allowing the anode and cathode reaction products to mix and to react together. This allows chlorine to react with hydroxide to form hypochlorite and finally sodium chlorate. In a two compartment-cell, such as a chlor-alkali cell, the electrodes are physically separated and thus their products cannot react together. These cells can be operated without SD and can produce sodium chlorate under certain conditions (Millet, 1990) (Delmas & Ravier, 1993). The usual electrolytic reactions operating in chlor-alkali cells are as follows:

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 55 - - 6Cl  3Cl2 + 6e (20)

- - 6H2O + 6e  3H2 + 6OH (21)

Overall: 6NaCl + 6H2O  3Cl2 + 3H2 + 6NaOH (22)

If the process is modified so that the chlorine gas is reacted with the hydroxide solution, sodium chlorate can also be generated as shown in eq. 23 below (Tilak & Chen, 1999):

- - - 3Cl2 + 6OH  5Cl +ClO3 + 3H2O (23)

with counter-ions: 3Cl2 + 6NaOH  5NaCl + NaClO3 + 3H2O (24) Combined (22 & 24): 6NaCl + 6H2O + 6NaOH  5NaCl + NaClO3 + 3H2O + 3H2 (25) Eq. 25 simplified: NaCl + 3H2O  NaClO3 + 3H2 (6)

It can be seen that overall, the process is chemically identical to the conventional undivided cell process but in practice quite different. Chlorine is produced in the anode compartment of a membrane chlor-alkali cell is hydrolysed into hypochlorous acid (eq. 2) (Hakansson, et al., 2004). The pH and temperature of the solution of hypochlorous acid is then maintained so that the formation of chlorate is maximised (pH 6-6.5 at around 80 °C). At this pH, the correct ratio of hypochlorite and hypochlorous acid is achieved. Equation 26 shows the balanced equation, in this case showing sodium hydroxide acting as a base. The cathode compartment would serve as the source of sodium hydroxide that would be introduced into the chlorate reactor and in limited amounts to a chlorine absorption unit or anode compartment (Delmas & Ravier, 1993). The use of sodium hydroxide for pH control in this manner potentially avoids the need for further buffering agents to be added to the electrolyte.

3Cl2 + 3H2O ⇄ 3HOCl + 3HCl (2) 3HOCl + NaOH ⇄ 2HOCl + NaClO (26)

The current process involving SD uses undivided electrolysis cells while chlor-alkali cells use membrane cells and would also involve separate chlorate reactors and gas processing equipment. A change to this type of cell would require a rebuild of current plant technology as all existing single compartment cells would need to be scrapped.

It is considered that modified chlor-alkali type-cells could be technically feasible for the production of chlorate without the use of SD. For this reason, further consideration to production of chlorate via two-compartment cells and reaction of chlorine with sodium hydroxide will be given, although the high cost of the associated production plant replacement is of note.

Table 4-20: Research into two-compartment electrolytic systems – Cook, 1975 Parameter Details Year 1975 Source Cook (1975) Associated company/ Hooker Chemicals Plastics Corp research organisation Objective of research or - A process for producing alkali metal chlorate using two different cells. The first invention being a two-compartment membrane cell and the second being a conventional single-compartment chlorate cell.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 56 Table 4-20: Research into two-compartment electrolytic systems – Cook, 1975 Parameter Details - The patent describes a process that produces sodium hydroxide, chlorine, sodium chlorate and hydrogen as outputs of one overall process Relevance to the chlorate High relevance, but no mention is made of the use of SD in the electrolyte. A process conventional cell is used so use of Cr(VI) can be expected Key changes to current - The examples describe a process producing 1.7 tons per day of sodium chlorate chlorate process and using the linked cells. The first cell produces a concentration of 100 g/L of sodium notable improvements and chlorate and this is increased to 430 g/L in the second cell. shortcomings - With a current efficiency of 94%, at a cell voltage of 4.2 V and a current density of 4 A/sq. inch (0.62 kA/m2). - Part of the hydrogen generated is burned with part of the chlorine produced to generate hydrogen chloride. This is then used for pH control at some stages. It is not clear how much of the hydrogen produced is diverted in this manner Presence of Cr(VI) in the Handling of Cr(VI): the patent does not mention the use of any electrolyte additives electrolyte nor describe any steps to limit corrosion. As the chlorate is primarily manufactured in a conventional chlorate cell, it is expected that Cr(VI) would be used as normal. Presence of Cr(VI) in electrolyte: Cr(VI) could be expected to be present in the electrolyte

Table 4-21: Research into two-compartment electrolytic systems – Millet, 1990 Parameter Details Year 1990 Source Millet (1990) Associated company/ Atochem (Arkema) research organisation Objective of research or - Production of alkali metal chlorates or perchlorates using a two-compartment invention membrane cell - Avoiding the use of Cr(VI) was a stated objective of the patent Relevance to the chlorate High relevance to both chlorate process and the elimination of the use of Cr(VI) process Key changes to current - The patent claims processes carried out at pH 6.2-6.6 controlled by introducing chlorate process and sodium hydroxide from the cathode compartment into the anode compartment. notable improvements and - The examples employ an electrolyte consisting of 150-160 g/L NaCl and 500 g shortcomings NaClO3 at a temperature of 63-71 °C and pH 6.3-6.4 - A current of 10 A was applied to a 0.5 dm2 electrode (equivalent to 2 kA/m2) but no mention of cell voltage is made - The yield of sodium chlorate is claimed at 87.3%-93% based on the oxygen present in the chlorine in the absence of SD. - Yield of pure hydrogen is claimed at practically equal to 100%. - No mention of how long the process was operated for nor the scale of the process - Two examples are shown with the following chlorate generation efficiencies based on amount of oxygen formed

Temp Anolyte pH Anolyte Membrane (by Sodium recycling flow Dupont) chlorate rate efficiency 63 °C 6.3-6.4 70 L/h Nafion 117 87.3% 71 °C 6.3-6.4 160 L/h Nafion 902 93% Presence of Cr(VI) in the Handling of Cr(VI): the invention is claimed without the use of chromates. electrolyte Presence of Cr(VI) in electrolyte: No SD present in the electrolyte

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 57 Table 4-22: Research into two-compartment electrolytic systems –Delmas & Ravier, 1993 Parameter Details Year 1993 Source Delmas & Ravier (1993) Associated company/ ELF Atochem (Arkema) research organisation Objective of research or - Method of manufacturing chlorate alkali metal by electrolysis in a membrane cell invention without adding chromium Relevance to the chlorate High relevance to both chlorate process and the elimination of the use of Cr(VI) process Key changes to current - The invention comprises of two linked chlor-alkali cells and a scrubbing column chlorate process and and does not involve the use of Cr(VI) notable improvements and - The process preferably runs at pH 6.5-7 and temperature of 70-90 °C shortcomings - Chlorate production is carried out by transfer of chlorine gas and the solution of alkali metal hydroxide from a chlor-alkali cell to react in a scrubbing column - pH maintained at 6.5-7 in the scrubbing tower by addition of sodium hydroxide from cathode compartments - Column output is recycled by circulating in a second chlor-alkali cell - The output of the anode compartment of the second cell is diverted to a crystalliser to obtain the chlorate and to recycle mother liquors back to the second chlor-alkali cell - The method is claimed to result in a reduction in water consumption: the usual method of production of sodium chlorate requires the introduction of 1,563 kg of water per tonne of NaClO₃, associated with sodium chloride fed in the form of brine containing 26% by weight of NaCl. In the process disclosed, the second cell is fed by a stream from the reaction between chlorine and the aqueous solution at 33% by weight of soda with the introduction of 719 kg of water per tonne of NaClO₃ product. There is a saving of 844 kg of water that would otherwise need to be evaporated in a sodium chlorate crystallisation facility Presence of Cr(VI) in the Handling of Cr(VI): no use of SD electrolyte Presence of Cr(VI) in electrolyte: no presence of SD in the electrolyte

Alternative 9: Oxygen-consuming gas diffusion electrodes

A recently developed technology for an improved chlor-alkali process replaces the conventional steel or titanium cathodes in chlor-alkali membrane cells with an oxygen-consuming electrode, fundamentally changing the chemistry of the process. This change results in the production of chlorine and sodium hydroxide without the production of hydrogen. The process is claimed to result in up to 30% reduction in electricity requirements in laboratory trials (Chlistunoff, 2004). However, this is at the cost of a valuable hydrogen co-product and significant technical barriers to limit cathode corrosion are yet to be overcome. The use of oxygen-consuming electrodes in the production of chlorate is currently under patent (Hakansson, et al., 2004). Although the patent states that, an embodiment of the patent does not necessitate the use of chromates, the examples in the patent use SD at a concentration of 3 g/L, as shown in Table 4-23.

The purpose of the project was continuation of the development of new chlor-alkali electrochemical reactors (ECRs) that employ oxygen-depolarised cathodes. Due to their lower operating voltages, the oxygen-depolarised reactors consume up to 30% less electrical energy per unit weight of the products (chlorine and caustic soda), than the state-of-the-art membrane electrolysers with hydrogen-evolving cathodes.

Evidence of commercial use of this alternative could not be established, and the applicant has no knowledge of any such commercial use. The elimination of the use of SD under this method has not

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 58 been demonstrated, therefore, this cannot be considered a realistic alternative for the purposes of this AfA.

Table 4-23: Research into oxygen-consuming gas diffusion electrodes – Hakansson et al, 2004 Parameter Details Year 2004 Source (Hakansson, et al., 2004) Associated company/ AkzoNobel (EKA) research organisation Objective of research or - A process for producing alkali metal chlorate in an electrolytic cell that is divided invention by a cation selective separator into an anode compartment in which an anode is arranged and a cathode compartment in which a gas diffusion electrode is arranged - The patent is aimed at developing a chlorate cell where the cost and handling of HCl and NaOH are reduced while improving energy efficiency Relevance to the chlorate High relevance, but the embodiments described use SD at typical electrolyte process concentrations Key changes to current - The experiment was run as a batch process with a start volume in the reactor chlorate process and vessel of 2 litres. The start concentration of the electrolyte in the anode notable improvements and compartment was 110 g of NaCl/L, 550 g of NaClO3 and 3 g/L SD. This solution shortcomings was pumped through the anode compartment of an electrolytic cell at a rate of 25 L/h corresponding to an approximate linear velocity across the anode of 2 cm/s - An excess of oxygen gas was fed to the gas compartment. The cell was a laboratory cell containing an anode compartment with a dimensionally stable (DSA) chlorine anode and a cathode compartment with a silver plated nickel wire gas diffusion electrode loaded with uncatalysed carbon (5-6 mg/cm2). The anode and cathode compartments were separated by a cation selective membrane, Nafion 450, and the distance between each electrode and the membrane was 8 mm - Electrolysis was conducted at a temperature of 70 °C in the electrolysis cell, a current density of 0.2-3 kA/m2 and at a pH of 6.2. The current was varied between 0.5- 6.3 A. The electrolysis was run for 30 h - The achieved efficiencies under two examples are shown below.

Example – conditions Current Current Current efficiency for efficiency for efficiency for electrolysis chlorine chlorate (based on OH-) 50 g/L NaOH solution was pumped through the cathode 92% 100% 95% compartment at linear velocity across the cathode of 2 cm/s Solid sodium chloride was added to the reactor vessel and fed to 100% 97% the anode compartment at a rate of 0.71 g/Ah

The cell voltage for the overall chemical reaction in the gas diffusion electrode cell is about 2V, which implies that considerable operation costs can be saved by replacing the hydrogen evolving cathode with a gas diffusion electrode acting as cathode Presence of Cr(VI) in the Handling of Cr(VI): the invention is claimed with and without the use of chromates. electrolyte However, example embodiments in the patent use SD at 3 g/L Presence of Cr(VI) in electrolyte: as per typical operating conditions, where SD is used

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 59 Alternative 10: Polymeric cathode film coatings

Finally, the use of polymeric films as cathode coatings has been discussed in the literature in the past. A 1981 patent by Bommaraju et al discussed the elimination of chromates from the electrolyte in favour of a polymeric cathodic film made of chlorinated or fluorinated polymers and copolymers (see Table 4-24). An example shown based on a proprietary tetrafluoroethylene fluorocarbon showed comparable reductions in current efficiency for chlorate and/or hypochlorite reduction when compared to the use of a conventional steel cathode in a chlorate electrolyte which includes a chromate additive.

Nevertheless, this patent is now more than 30 years old; evidence of commercial use of this alternative could not be established, and the applicant has no knowledge of any such commercial use. This novel method cannot be considered a realistic option for the replacement of SD and will be given no further consideration in favour of other options discussed in this AoA.

Table 4-24: Research into polymer cathode film coatings – Bommaraju et al, 1981 Parameter Details Year 1981 Source (Bommaraju, et al., 1981) Associated company/ Hooker Chemicals & Plastics Corp. research organisation Objective of research or Provision of a viable alternative to the use of chromates in chlorate cells, without invention sacrificing cell performance and efficiency through the use of a protective porous film on the surface of the cathode Relevance to the chlorate High relevance process Key changes to current - A non-conductive material is used to generate a cathode film with an average chlorate process and thickness of from about 10-4 μm to about 103 μm, and has sufficient porosity to notable improvements and permit the transport of hydrogen molecules leaving the cathode shortcomings - Materials that are substantially nonconductive and chemically resistant or inert to the chlorate solution, remaining stable in the solution during conditions of prolonged operation include various halogenated polymers, copolymers and resins, both of the thermosetting and thermoplastic variety, and particularly chlorinated and fluorinated polymers and copolymers, such as polyvinyl chloride, Teflon, Kel-F (proprietary chlorotrifluoroethylene), and Kalgard (proprietary tetrafluoroethylene fluorocarbon). The polymeric material may also be a thermoplastic polymer, such as polysulphone, or an elastomeric material, such as neoprene rubber or a silicone material. Also suitable as film-forming materials are various metallic and non-metallic oxides such as zirconium dioxide, titanium

dioxide, tantalum oxide, chromic oxide (Cr2O3), vanadium trioxide, iron oxide, cobalt oxide, aluminium oxide, hafnium dioxide, niobium pentoxide, and silicon dioxide - The film-forming material can be applied to the substrate by plasma or thermal spraying, chemical vapour deposition, emulsion techniques, or other suitable techniques which will form a thin, porous surface on the substrate material - Examples of the invention have been described where the film is formed either

with Kalgard or Cr2O3. These examples showed comparable reductions in current efficiency for chlorate and/or hypochlorite reduction when compared to the use of a conventional steel cathode in a chlorate electrolyte which includes a chromate additive Presence of Cr(VI) in the Handling of Cr(VI): SD was eliminated in the examples shown in the patent electrolyte Presence of Cr(VI) in electrolyte: Cr(VI) would not be present in the electrolyte

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 60 4.2.4 Consultation with the supply chain

Given that SD is only used as a process aid and does not play a role in the final product (in which chromium is present as an impurity at levels below 5ppm), consultation with customers of the applicant was not deemed necessary for the purposes of the AoA and was not undertaken.

On the other hand, this AoA document is the result of extensive consultation between the independent third party that was contracted to develop this AoA and the applicant. The applicant was specifically consulted regarding the alternatives identified through data searches in order to ensure that the information in the open literature is relevant and accurate and to gauge the level of internal knowledge regarding the feasibility of alternative technologies. Questionnaires, email communications and face to face meetings were used for the purposes of information gathering and verification. 4.3 Screening of identified alternatives

4.3.1 Screening of identified alternatives for commercialisation status

As already explained, the applicant has been a member of a consortium of sodium chlorate manufacturers (SDAC) who have worked together towards the preparation of their individual AfAs, within the confines of Competition Law and with an independent third party in the role of a trustee. Each individual applicant within this consortium has supported the development of the AoA by providing information on the current commercialisation status of the identified alternatives. The aim of this analysis was two-fold:

 Establish which alternatives (if any) are immediately or otherwise readily available for adoption as a replacement for SD  Collect information on the availability of the alternatives that would be shortlisted, to inform the analysis presented in Section 5 of the AoA.

The analysis prepared on the basis of consortium members’ submissions has been used in the preparation of all members’ AoA documents.

The overall conclusion from Table 4-25 is that none of the identified alternatives are commercially available at present and will not become available by the sunset date. Several of the identified alternatives are invariably solutions that have only been trialled at the laboratory scale with often unsatisfactory results. With the exception of Cr(III) compounds (in this AoA, represented by CrCl3), none of the alternatives has found commercial use in the manufacture of sodium chlorate and among the manufacturers of sodium chlorate who are applying for Authorisation, Cr(III) has only been used by the competitor who has filed the relevant patent application. Certain alternatives that might be considered as being closer than others to commercialisation because some experience with them exists (e.g. use of Ru-based anodes which would be adapted to work as cathodes, or two- compartment cells that have been used in the chlor-alkali industry) require a considerable length of time before they could be implemented.

Conclusion: two of the identified alternatives, two-cell systems with oxygen-consuming diffusion electrodes and polymeric film coatings are eliminated on the basis of commercialisation issues; the former has not been proven beyond the lab scale and only in the presence of SD, while the latter has

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 61 not found commercial applications for over 30 years, therefore, cannot be considered a realistic option. The remaining alternatives will be subject to further screening.

4.3.2 Screening of identified alternatives for suitability in eliminating Cr(VI) exposure

An alternative to SD in the applied for use should ideally eliminate the use of SD and any associated worker exposure to the Cr(VI) anion that confers to SD its SVHC properties during the sodium chlorate production process (worker exposure for downstream users as well as consumer exposure are of no relevance to the applied for use, as discussed in the CSR). However, it is not always the case that alternatives may eliminate the use of SD or indeed the exposure to Cr(VI). Some alternatives may limit the handling of SD solution but may still result in the presence of Cr(VI) in the electrolyte; other alternatives may simply need the addition of SD (possibly, at variable concentrations) otherwise they would not be able to ensure the required current and process efficiency of the chlorate process. It is clear that if an alternative requires the addition of a similar dose of SD into the electrolyte, it could not be assumed a suitable option for the replacement of SD.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 62 Table 4-25: Commercialisation status of identified alternatives for SD in the sodium chlorate process Commercial availability for the sodium chlorate process Is this a realistic Alternatives If commercially used, timeframe for If not commercially used, timeframe Currently used? alternative option? implementation for becoming available No Potential alternative substances 1 Chromium (III) Not by the applicant Uncertain. Relevant patent application - Not immediately available chloride (by a direct competitor) is at an early and most likely stage of the process which can typically unavailable at the sunset take several years date. NB. The applicant has some experience with recycling Cr(III) into the electrolyte 2 Sodium molybdate No - Impossible to estimate; still under Not currently research with significant shortcomings 3 Rare Earth metal No - Impossible to estimate; still under Not currently, overcoming (III) salts research with significant shortcomings the poor solubility is a major challenge

No Potential alternative cathodic coatings 4 Molybdenum- No - Uncertain; depends on the rate of Not currently based cathode replacing of cathodes at each affected coatings plant 5 Ruthenium-based There are Ru-coated DSA- Impossible to estimate. Not currently cathode coatings type anodes on the If the technology would be effective in replacing SD (not so far the case), the first market; these cannot be stage of implementation could potentially take less than a year, for companies used as cathodes since with access to Ru-based electrode technology. they are not stable due to Full implementation would depend on the rate of replacing of cathodes at each hydride formation on the affected plant titanium substrate, which ‘peels off’ the coating. The availability of Ru- coated cathodes is limited

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 63 Table 4-25: Commercialisation status of identified alternatives for SD in the sodium chlorate process Commercial availability for the sodium chlorate process Is this a realistic Alternatives If commercially used, timeframe for If not commercially used, timeframe Currently used? alternative option? implementation for becoming available 6 Zirconium- based No Impossible to estimate, as past trials have been unsuccessful. Not currently cathode coatings If the technology would be effective in replacing SD (not so far the case, concerns exist over the coating’s lifetime), the first stage of implementation could potentially take less than a year, for companies with access to the electrode technology. Full implementation would depend on the rate of replacing of cathodes at each affected plant No Potential alternative cathode materials 7 Ruthenium alloy Not for cathodes, already Uncertain; depends on the rate of replacing of cathodes at each affected plant; Not currently; may not cathodes in use as anodes uncertain commercial availability of the required alloys eliminate the use of SD No Potential alternative electrolytic processes 8 Two-cell Not for chlorate Uncertain; entire new plant would be - Not currently electrolytic production required systems 9 Two-compartment No - Impossible to estimate; still under Not foreseeably; will not electrolytic cells research. Lab trials used SD in the be considered further with oxygen- electrolyte given the use of SD consuming gas diffusion electrodes 10 Polymeric cathode No - Impossible to estimate Given the date of the film coatings patent (1981) this cannot be considered realistic and will not be considered further

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 64 The following table summarises the available information on the identified alternatives and identifies those that would not eliminate worker exposure to Cr(VI), thus in principle would not make suitable alternatives for SD in the applied for use. The colours signify elimination of exposure (green), reduction of exposure or uncertain change (orange) and no change on current exposure conditions (red).

Table 4-26: Preliminary screening of the suitability of the identified alternatives in eliminating worker exposure to SD Current Alternatives Comparison to SD situation No Potential alternative substances 1 Chromium (III) chloride Addition of SD Better but not optimal: eliminates handling of SD during leading to 3-6.5 loading, worker exposure to Cr(VI) largely remains g SD/L in unchanged 2 Sodium molybdate electrolyte Better but not optimal: to achieve acceptable process efficiency, low presence of Cr(VI) needed 3 Rare Earth metal (III) salts Better: no Cr(VI) required No Potential alternative cathodic coatings 4 Molybdenum-based As above Uncertain: past research has shown that SD is either not cathode coatings replaced or may still need to be present at lower concentrations (0.1 g/L) 5 Ruthenium-based No improvement: Cr(VI) is required and a SD dosage cathode coatings similar to current would be required. The shortcomings identified in the published research will need to be overcome 6 Zirconium- based Uncertain: could eliminate the use of SD but this is not cathode coatings certain, as some of the past research was not aimed at replacing SD No Potential alternative cathode materials 7 Ruthenium alloy As above No improvement: some alloys used in lab tests may cathodes contain up to 50% Cr which would reduce the consumption of SD but might not eliminate the presence of Cr(VI) in the electrolyte. Later research indicates use of 3 g/L SD No Potential alternative electrolytic processes 8 Two-cell electrolytic As above Better: would eliminate the use of SD and the presence systems of Cr(VI) in the electrolyte

The table suggests that ruthenium-based cathode coatings and ruthenium alloy cathodes would offer no improvement, therefore they cannot be considered realistic alternatives for SD. In addition, molybdenum-based cathode coatings and zirconium-based cathode coatings are likely to require addition of SD at typical concentrations of SD in order for performance to be maintained at acceptable standards. Cr(III) chloride and, possibly, sodium molybdate may indeed reduce worker exposure to SD but certainly do not eliminate exposure to Cr(VI); CrCl3 in particular reduces the handling and exposure to Cr(VI), as SD does not need to be physically handled and dosed into the system, but it does not eliminate exposure to Cr(VI), as it is oxidised into Cr(VI) in the electrolyte thus generating a Cr(VI) concentration essentially identical to that obtained from the addition of SD under the applied-for use-scenario The result is that with CrCl3 the estimated exposure reduction amounts to only ca. 20% of aggregate exposure of day workers only. All other employees (unit workers and central laboratory workers) would not benefit from reduced exposure to Cr(VI). This is further elaborated in Section 5.2.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 65 Only REM salts and two-cell electrolytic systems may claim that they require neither the addition nor the presence of SD in the electrolyte (but the former is clearly technically infeasible, as discussed below).

4.3.3 Screening of identified alternatives against the technical feasibility criteria

Comparison of SD to potential alternative substances

A list of technical feasibility criteria were developed and discussed in Section 2 (see Table 2-6). This development involved all members of the SDAC. The applicants were asked to:

 Provide quantitative values or qualitative descriptions of how each of the technical feasibility criteria are fulfilled by SD along with a minimum value or threshold that must be achieved by an alternative  Use the technical feasibility criteria and their thresholds or ideal values/ranges to (a) compare each alternative substance to SD, and (b) compare the SD-based state-of-the-art chlorate technology to the alternative technologies identified, in support of the information obtained from the literature review.

In some cases, the values provided by individual applicants within the consortium. Where necessary, clarification was sought to identify the reasons for any deviation and to establish the level of knowledge and practical experience of each applicant with the alternatives under consideration. Where appropriate, applicant-specific information is provided in the following table and this has been marked as confidential.

Generally, a semi-quantitative approach was taken where applicants compared in turn each alternative to SD as “Similar”, “Better” or “Worse” and, where possible, additional justification and explanation was provided.

This systematic comparison of alternatives is shown in Table 4-27. The colouring code of the cells is as follows:

 Green colour indicates an alternative that meets and exceeds the threshold of a criterion (i.e. the substance is “Better” than SD)  White colour indicates an alternative that meets the threshold/range of a criterion (i.e. the substance is “Similar” than SD)  Orange colour indicates an alternative that may or may not meet the threshold/range of a criterion, i.e. there is uncertainty or it may marginally fail the criterion  Red colour indicates an alternative that does not meet the threshold/range of a criterion (i.e. the substance is “Worse” than SD).

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 66 Table 4-27: Comparison of alternative substances to SD against the technical performance criteria Criteria Sodium dichromate Alternative substances Result or numerical Threshold or Chromium (III) chloride Sodium molybdate Rare Earth metal (III) salts value achieved by acceptable range for sodium dichromate replacing sodium dichromate Formation of No suitable  2 % Similar: Cr(III) is oxidised to Uncertain: it creates a Worse: salts are not soluble at protective film numerical value, but Cr(VI) immediately (in the protective film but the process conditions. In trials, permeable to hydrogen efficiency presence of active chlorine) thickness of the film grows too rare earth metals started to hydrogen >98 % and acts as if SD had been used thick and energy consumption precipitate at pH 4.8 and trials as an additive will increase at normal operating pH 6.5 were not even possible to perform. REM hydroxide film is not permanent at typical operating conditions Formation of No numerical value Ideally, similar to SD Similar (assumed) Worse: worse current Worse: salts are not soluble at protective film efficiency implies lower process conditions impermeable to selectivity hypochlorite

Control of oxygen SD achieves <2.5% O2 Ideally, less than Similar (assumed) Worse: research indicates 3.6- Worse: salts are not soluble at formation (and evolution 2.5% by volume of O2 4.8% O2 generation, suggesting process conditions control of oxygen in H2 with a Mo(VI) needs to be as low as content in maximum of 4.0% possible hydrogen) Cathode protection Cannot be At least 8 years Similar (assumed) Uncertain Worse: salts are not soluble at (corrosion quantified; minimum cathode lifetime process conditions inhibition) lifetime of cathode is assumed to be 8 yrs

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 67 Table 4-27: Comparison of alternative substances to SD against the technical performance criteria Criteria Sodium dichromate Alternative substances Result or numerical Threshold or Chromium (III) chloride Sodium molybdate Rare Earth metal (III) salts value achieved by acceptable range for sodium dichromate replacing sodium dichromate pH buffering 6.0-6.5 6.0-6.5 Similar (assumed) Worse: addition of phosphate Worse: salts are not soluble at buffer is required; this leads to process conditions cracks on the cathodic film and affects the durability of the anodes Current efficiency >95% Energy efficiency: Similar (assumed) Worse: 80-91% or lower. Worse: salts are not soluble at and energy 5,230 kWh/t ''#A#''% or more, However, similar process process conditions consumption ideally >95% efficiency can be reached by '''''''''''''''' '''''''''''''''''' only partially replacing SD with ''''' ''''''' #A#'''''''''''''' molybdate '''''''''''''''''. Total energy consumption: 5,700 kWh/t chlorate or less Solubility in Highly soluble (Highly) soluble Similar (assumed) Similar Worse: salts are not soluble at electrolyte Solubility of SD: process conditions ca. 2,355 g/L Impurities in <5ppm Cr in solid Each impurity must Similar (assumed) Worse: presence of Uncertain but probably worse: chlorate product chlorate product be considered molybdenum in the chlorate probably higher impurity separately. Metals product would destabilise the content due to lack of solubility are particularly ClO2 reaction detrimental to ClO2 generation

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 68 The conclusions from this analysis are as follows:

 The only alternative substance that generally meets the technical feasibility criteria is CrCl3 (more accurately, Cr(III)), as it is assumed to effectively give Cr(VI) in the electrolyte and thus deliver the technical functions of the chromates within the chlorate cell). However, the applicant does not have access to the details of this technology and therefore the exact conditions and parameters under which such performance equivalence can be obtained are not known  Rare Earth Metal salts are clearly infeasible replacements for SD. Their solubility at process conditions is very poor and prevents them from performing their intended role. No solution has been found so far on making the solubility of these compounds acceptable for the purposes of sodium chlorate production. These substances cannot be considered technically feasible alternatives  Sodium molybdate is accompanied by a major hazard concern, the generation of O2 in quantities that may lead to explosive mixtures with H2, which is also released. This inherent hazard does not exist in the current technology that is based on SD. Sodium molybdate is a poorer pH buffer, which requires the addition of phosphates; however, the presence of phosphates has an adverse effect on the stability of the cathodic film and the durability of the anodes. In addition, Mo(VI) is accompanied by poorer current efficiency, which may be around or below 90%, unless some SD is added to the electrolyte. Finally, the presence of metal impurities in the chlorate product would have adverse effects on the stability of the processes of the applicant’s customers (e.g. ClO2 formation).

Comparison of the SD-based chlorate production process to potential alternative technologies

A similar comparison of the SD-based chlorate process was performed by the applicants for alternative technologies. The overview of comparison against the technical feasibility criteria is shown in Table 4-28. The colour coding is similar to the one in the previous table on alternative substances. The following conclusions may be reached:

 All of the alternative technologies have technical disadvantages, for example, poor pH buffering would require in each and every case the use of phosphate additives which could cause problems at the anode  Alternatives other than two-cell electrolytic systems are shrouded by uncertainty as regards their ability to generate a film around the cathode of ‘equivalent’ impermeability to hypochlorite and permeability to hydrogen  The control of O2 formation is likely to be worse for Ru-based coatings  The use of two-cell electrolytic systems might lead to higher energy consumption The stability of cathode coatings will define whether metal impurities would be found in the chlorate product, thus causing safety concerns for the subsequent use of the chlorate by the applicant’s customers  Technologies other than two-cell electrolytic systems may not be able to eliminate the use of SD. Notably, relevant past research has not really focused on the elimination of SD and for Ru-based cathode coatings and Ru alloys there are well-founded concerns that Cr(VI) will continue to be present in the electrolyte.

Conversely, from a more positive perspective,

 Mo-based coatings may be accompanied by improvements in current efficiency (this may also be the case for Ru-based coatings and Ti-Ru alloys, but this is uncertain)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 69  Two-cell electrolytic systems use separated electrodes, thus they eliminate the need for the formation of selective films on the cathode and would prevent the development of explosive atmospheres as the generated gases (H2 and O2) would not be allowed to mix.

Overall, it would seem that two-cell electrolytic systems would have some distinct advantages over other technologies but would not be ‘trouble-free’. Ru-based coatings and Ru alloys would appear to be the least appropriate alternative technologies.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 70 Table 4-28: Comparison of alternative technologies to SD-based chlorate process against the technical performance criteria Criteria Sodium dichromate Alternative technologies Result or Threshold or Mo-based Ru-based coatings Zr-based coatings Ru alloy cathodes Two-compartment numerical acceptable range coatings electrolytic systems value achieved for replacing by sodium sodium dichromate dichromate Formation of No suitable  2 % Uncertain: Uncertain: different Uncertain: Uncertain: different Not relevant to this protective numerical different technology to SD. It different technology. The film technology: film value, but technology to SD. may perform well if SD technology. The is not formed but cells/electrodes are permeable hydrogen The film is not is present. RuO2 film is not formed imposed; its separated to hydrogen efficiency >98% formed may reduce cathodic but imposed; its effectiveness is electrolytically overpotential to effectiveness is unclear but imposed as a hydrogen evolution. unclear coating Coating has shown poor stability Formation of No numerical Ideally, similar to Uncertain: Worse: different Worse: different Uncertain: different Not relevant to this protective value SD different technology to SD. technology. The technology. The film technology: film technology to SD. RuO2 coating film is not formed is not formed but cells/electrodes are impermeable The film is not effectiveness in but imposed; ZrO2 imposed; its separated (no to formed preventing parasitic based coatings effectiveness is hypochlorite at the hypochlorite electrolytic ally reactions is poor reduce the rate of unclear. Lab tests cathode: the but imposed as a (reduction of hypochlorite with Ru-Ti alloys membrane prevents coating hypochlorite and reduction, but do would suggest a low the migration of chlorate ions) not entirely rate of hypochlorite hypochlorite into the inhibit it (unless reduction cathode compartment) perhaps combined with other oxides)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 71 Table 4-28: Comparison of alternative technologies to SD-based chlorate process against the technical performance criteria Criteria Sodium dichromate Alternative technologies Result or Threshold or Mo-based Ru-based coatings Zr-based coatings Ru alloy cathodes Two-compartment numerical acceptable range coatings electrolytic systems value achieved for replacing by sodium sodium dichromate dichromate Control of SD achieves ideally, less than Uncertain Marginally worse: Ru Uncertain Similar: Ru-Ti alloys Better: cathode and oxygen <2.5% O2 2.5% by volume released from the have shown low anode are physically formation evolution of O2 in H2 with a coating can increase evolution of oxygen, separated by a (and control maximum of the bulk formation of but generally membrane and of oxygen 4.0% oxygen the bulk of anodic produced gases (H2 & content in formation of oxygen is O2) do not mix hydrogen) not influenced by change of the cathode coating/material Cathode Cannot be At least 8 years Uncertain, Uncertain: requires Uncertain Worse: no film or Better: no particular protection quantified; cathode lifetime possibly similar, further study coating at all; need for this. The (corrosion minimum depends on presence of iron in special materials used inhibition) lifetime of additives the alloy may lead to are not easily corroded cathode is 8 replacing SD corrosion effects. Ru years alloys with Fe/Al show poor stability in acidic pH and require addition of metals such as Ta to improve corrosion resistance

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 72 Table 4-28: Comparison of alternative technologies to SD-based chlorate process against the technical performance criteria Criteria Sodium dichromate Alternative technologies Result or Threshold or Mo-based Ru-based coatings Zr-based coatings Ru alloy cathodes Two-compartment numerical acceptable range coatings electrolytic systems value achieved for replacing by sodium sodium dichromate dichromate pH buffering 6.0-6.5 6.0-6.5 Worse: need for Worse: need for Worse: need for Worse: need for Worse: need for addition of addition of buffering addition of addition of buffering adjustment of pH (e.g. buffering agent, agent, e.g. sodium buffering agent, agent, e.g. sodium NaOH/HCl feedback e.g. sodium phosphate. e.g. sodium phosphate, expected loops) phosphate (3 g/L). Phosphates as Cr phosphate, Phosphates as Cr replacement may expected replacement may cause problems at the cause problems at anode the anode Current >95% Energy Better: according Uncertain: past Uncertain, Uncertain, probably Worse: using typical efficiency 5,230 kWh/t efficiency: #A#'% to patents, a research would probably worse: worse: past research electricity consumption and energy or more, ideally lower cell voltage suggest it is possibly 91% current would suggest it is figures for a chlor-alkali consumption >95% '''''''''''''''' can be achieved better (activated efficiency possibly better by plant, the overall ''''''''''''''#A#'''' ''''' using this cathodes decrease reported for ZrO2 reducing specific energy consumption '''''' '''''''''''''''''''' technology, energy consumption), modified with energy consumption can be calculated to be ''''''''''''''''. resulting in a if RuO2 used alongside Y2O3 on a (Ru alloys lead to a worse than what is Total energy lower energy other oxides but only zirconium plate in reduction of the achieved with SD consumption: consumption in the presence of SD a hypochlorite cell hydrogen ideally 5,700 overpotential). kWh/t chlorate Materials based on or less Fe3Al alloy doped with Ru and Ta may still require SD (3 g/L) Solubility in Highly soluble (Highly) soluble Not relevant Not relevant Not relevant Not relevant Not relevant electrolyte Solubility of SD: ca. 2355 g/L

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 73 Table 4-28: Comparison of alternative technologies to SD-based chlorate process against the technical performance criteria Criteria Sodium dichromate Alternative technologies Result or Threshold or Mo-based Ru-based coatings Zr-based coatings Ru alloy cathodes Two-compartment numerical acceptable range coatings electrolytic systems value achieved for replacing by sodium sodium dichromate dichromate Impurities in <5ppm Cr in Each impurity Uncertain but Uncertain but Uncertain but Uncertain but Better quality due to chlorate solid chlorate must be probably worse: probably worse: it probably worse: probably worse: it fewer impurities product product considered it will depend on will depend on any it will depend on will depend on any separately. any additives additives used and the any additives additives used and Metals are used and the stability of the used and the the stability of the particularly stability of the coating. Presence of stability of the coating. Presence of detrimental to coating. Presence metals in the coating. Presence metals in the ClO2 generation of metals in the electrolyte (released of metals in the electrolyte (released electrolyte from the coating) electrolyte from the coating) (released from would give rise to (released from would give rise to the coating) concern the coating) concern would give rise to would give rise to concern concern

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 74 4.3.4 Screening of identified alternatives for practicality and (preliminary) economic feasibility

Members of the SDAC, including the applicant, were requested to outline the practical (engineering) steps that would be required for the implementation of each of the potential alternatives. They were also asked to identify the most critical of these steps and highlight any issues that would require substantial expenditure or extended timelines. The results are shown in Table 4-29. The conclusion on the realism of each alternative solution is highlighted in colour:

 Green, for feasible and readily implementable solutions  Orange, for alternative solutions with distinct engineering challenges and/or practicality issues  Red, for alternatives that are infeasible from a practical and engineering perspective.

We therefore can identify the following ‘groups’ of alternatives that may be feasible alternatives in terms of practicality:

 CrCl3 is the only solution that could theoretically be feasible to implement (in comparison to other alternatives), on the basis of its similarities to SD and the (limited) information that is publicly available. However, as the applicant does not have access to the relevant patent, access rights need to be secured first, after the patent has been granted, before the ease or not of implementation can be confirmed  Sodium molybdate, molybdenum-based cathode coatings, ruthenium-based cathode coatings, ruthenium alloy cathodes and two-cell electrolytic systems are technically demanding and not immediately available, but could theoretically be implemented in the longer term. Of these, the use of sodium molybdate as an additive would be the relatively simpler option. On the other hand, the use of new cathode coatings and alloys would require the gradual replacement of existing cathodes; due to the number of cathodes involved, this can only be undertaken over a long period. In addition, the implementation of two-cell systems would practically require a new plant to be set up  Rare Earth Metal salts and zirconium-based cathode coatings are not considered realistic. The former simply cannot work as additives to the electrolyte, and the latter have not been proven as their industrial upscale failed in the past.

4.3.5 Summary of screening process for alternatives

A summary of the entire screening approach presented above is given in Table 4-30. The colour code is as follows:

 Green: acceptable/feasible  Orange: feasible with complications and/or disadvantages in comparison to SD  Red: infeasible/unrealistic.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 75 Table 4-29: Practical and economic feasibility screening of potential alternatives Alternatives Practical steps required Key complexities of practical steps Conclusion No Potential alternative substances 1 Chromium (III) - Exact changes are unclear as the applicant has no - Need to wait for patent to be granted and become Uncertain feasibility compounds access to the details of the technology which is under available for licensing and cost, while 3rd patent application. It can be assumed that some - Unclear complexity but probably less complex than party patent changes to dosing so that Cr(III) can be added to the cell other alternatives that are less similar to SD application and and thus be oxidised to Cr(VI) in the electrolyte would - The cost of licensing is uncertain; reliance on this access to patent be required technology would also mean reliance on a patent held pending - Securing access to relevant patent once it is granted by a direct competitor (however, the applicant already has experience of re- circulating Cr(III) into the process) 2 Sodium - Needs to be scaled up from lab scale - In theory, technically feasible but scaling up fraught From an engineering molybdate - Substitution of overall volume of the electrolyte with uncertainties perspective feasible (solution of chlorate) available in a plant; potentially - Separation of SD from electrolyte and management of but yet unavailable possible to have both substances in the same the waste at the industrial electrolyte, cutting off one and adding the other - Changes to the equipment for handling hydrogen scale - Redesign of safety measures and hazard controls with - Equipment clean-up and preparation of new solution regard to hydrogen handling (vis-à-vis the increased would require downtime generation of O2 gas) 3 Rare Earth - Needs to be scaled up from lab scale - Very difficult to address the issue of poor From an engineering Metal (III) salts - Substitution of overall volume of the electrolyte solubilitySeparation of SD from electrolyte and perspective (solution of chlorate) available in a plant; unclear if management of the waste infeasible and possible to have both substances in the same - Changes to the equipment for handling hydrogen unavailable at the electrolyte, cutting off one and adding the other - Equipment clean-up and preparation of new solution industrial scale would require downtime No Potential alternative cathodic coatings 4 Molybdenum- - Needs to be scaled up from lab scale - Separation of SD from electrolyte and management of From an engineering based cathode - Substitution of overall volume of the electrolyte the waste perspective very coatings (solution of chlorate) available in a plant - Existing cathode replacement would be very costly and demanding and - Activation of new iron cathodic sheets would be will only be possible to undertake over several years or costly; unavailable necessary* involve a significant plant shutdown at the industrial - Assembly of new cathodic sheets and replacement of - Known patents are held by third parties scale; potential

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 76 Table 4-29: Practical and economic feasibility screening of potential alternatives Alternatives Practical steps required Key complexities of practical steps Conclusion all cathodes currently in use patent issue 5 Ruthenium- - Needs to be scaled up from lab scale - Separation of SD from electrolyte and management of From an engineering based cathode - Substitution of overall volume of the electrolyte the waste perspective very coatings (solution of chlorate) available in a plant - Existing cathode replacement would be very costly and demanding and - Activation of new Ti sheets would be necessary to give will only be possible to undertake over several years or costly; unavailable them the morphology (physical dimensions) of actual involve a significant plant shutdown on an industrial scale cathodes (current Ru-coated electrodes are used as - Compared to Mo-based coatings, additional cost for anodes) titanium rather than iron electrodes plus activation- - Assembly of new cathodic sheets and replacement of related costs for the use of precious metals all cathodes currently in use 6 Zirconium- - Needs to be scaled up from lab scale - Past attempts at industrial scale-up have failed From an engineering based cathode - Substitution of overall volume of the electrolyte - Separation of SD from electrolyte and management of perspective very coatings (solution of chlorate) available in a plant the waste demanding and - Activation of new iron cathodic sheets would be - Existing cathode replacement would be very costly and costly. Unavailable necessary will only be possible to undertake over several years or on an industrial scale - Assembly of new cathodic sheets and replacement of involve a significant plant shutdown all cathodes currently in use No Potential alternative cathode materials 7 Ruthenium - Needs to be scaled up from lab scale - Separation of SD from electrolyte and management of From an engineering alloy cathodes - Substitution of overall volume of the electrolyte the waste perspective very (solution of chlorate) available in a plant - Existing cathode replacement would be very costly and demanding and - Activation of new alloy cathodic sheets would be will only be possible to undertake over several years or costly; unavailable necessary involve a significant plant shutdown on an industrial scale - Assembly of new cathodic sheets and replacement of - Compared to Mo-based coatings, additional cost for and issues with all cathodes currently in use titanium rather than iron electrodes plus activation- market availability related costs for the use of precious metals - Uncertain commercial availability of alloys - May need to obtain access to patents held by 3rd parties No Potential alternative electrolytic processes 8 Two-cell - Substitution of overall volume of the electrolyte - To the applicant’s knowledge, this technology has not From an engineering electrolytic (solution of chlorate) available in a plant been used anywhere in the world for chlorate perspective feasible

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 77 Table 4-29: Practical and economic feasibility screening of potential alternatives Alternatives Practical steps required Key complexities of practical steps Conclusion systems - Replacement of all the cells would be necessary. The manufacture but requires a new brine treatment would require consequent overhauling, - In theory, technically feasible but scaling up fraught plant; very costly the crystallisation section debottlenecked and the with uncertainties and time-consuming electrical power supply increased without increasing - Replacement of all the electrolysers with new capacity electrolysis cell-rooms and long period of shut-down - New retention systems for Cl2 on the production of - Several years may be required for design planning and chlorate would be required scaling; even engineering implementation after all - Significant number of HAZOP studies and additional other steps have been taken could require several years training of personnel due to fundamental changes to - Costs will be several millions of Euros (including costly the chlorate production process membranes) - Effectively, a new plant would be required - The suitability of membranes (currently available for chlor-alkali cells) would be the critical factor in the feasibility of two-cell solutions for chlorate production

* Activation refers to the coating a base metal (Fe, Ti) with an active layer which acts as a catalyst for the generation of hydrogen. This active layer is composed of various metals and requires a treatment process of the surface base and its components. Also, the composition and morphology of the active layer must match very strict ranges of variation, i.e. an anode and a cathode, whether or not coated, are not interchangeable in their functions

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 78 Table 4-30: Summary of the screening of identified potential alternatives for SD in the manufacture of sodium chlorate Suitability as SD Comparison to SD Shortlisted for Commercialisation Engineering and Alternative replacement against technical Overall commentary further status economic feasibility (exposure) feasibility criteria analysis? No Potential alternative substances 1 Chromium (III) Not immediately Leads to a very small Uncertain due to lack Uncertain feasibility The option that could Yes – for compounds available and most reduction (ca. 20% for of knowledge of and cost while 3rd party prove to be the most completeness likely unavailable at some workers) but not conditions and patent application similar to current use only, as not sunset date elimination of Cr(VI) parameters of use. pending of SD but with only a considered exposure; eliminates Could prove similar to minor reduction in suitable for handling of SD Cr(VI) worker exposure to worker health Cr(VI). It cannot be protection considered a suitable option 2 Sodium Unavailable; To achieve acceptable Poorer current From an engineering Yes molybdate unknown future process efficiency, low efficiency and release perspective feasible concentrations of of O2 that may lead to but yet unavailable on A simple alternative; Cr(VI) in the electrolyte explosive an industrial scale however, wiith worse may be needed atmospheres; performance than SD phosphate presence and not proven on an has a serious effect on industrial scale anodes; metal impurities 3 Rare Earth Metal Unavailable; In theory, no Cr(VI) Poorly soluble; From an engineering No; cannot be Not soluble at normal (III) salts unknown future required technically infeasible perspective infeasible used chlorate production and unavailable on an conditions; unusable industrial scale

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 79 Table 4-30: Summary of the screening of identified potential alternatives for SD in the manufacture of sodium chlorate Suitability as SD Comparison to SD Shortlisted for Commercialisation Engineering and Alternative replacement against technical Overall commentary further status economic feasibility (exposure) feasibility criteria analysis? No Potential alternative cathodic coatings 4 Molybdenum- Unavailable; SD is either not Poorer pH buffering; From an engineering Patent literature Yes based cathode unknown future replaced or may still unclear reaction perspective very suggests reduced coatings need to be present at selectivity; better demanding and costly; energy consumption lower concentrations claimed energy unavailable on an and avoidance of SD (0.1 g/L) efficiency; phosphate industrial scale (but uncertain); not presence has a serious proven on an industrial effect on anodes; scale metal impurities 5 Ruthenium- Unavailable; Cr(VI) is required and a Poorer pH buffering From an engineering Unrpoven and No;itisnota based cathode unknown future dosage similar to and reaction perspective very infeasible; still requires suitable coatings current would be selectivity; metal demanding and costly; the use of SD; alternative, required impurities existing electrodes are unsuitable neither is it used as anodes rather technically than cathodes; feasible unavailable on an industrial scale 6 Zirconium- Unavailable; unknown Could eliminate the Generally uncertain; From an engineering Costly and demanding No; cannot be based cathode future use of SD, but this is poorer pH buffering; perspective very alternative; unavailable used coatings not certain may still require SD; demanding and costly; on an industrial scale metal impurities unavailable on an industrial scale

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 80 Table 4-30: Summary of the screening of identified potential alternatives for SD in the manufacture of sodium chlorate Suitability as SD Comparison to SD Shortlisted for Commercialisation Engineering and Alternative replacement against technical Overall commentary further status economic feasibility (exposure) feasibility criteria analysis? No Potential alternative cathode materials 7 Ruthenium alloy Unavailable; Some alloys used in lab Poorer pH buffering, From an engineering Technically interesting No;itisnota cathodes unknown future tests may contain up to cathode corrosion perspective very due to its potential to suitable 50% Cr. More recent protection and demanding and costly; reduce energy alternative, research indicates use reaction selectivity; unavailable on an consumption but, neither is it of 3 g/L SD metal impurities industrial scale and unproven, costly, raises technically issues with market concerns on cathode feasible availability lifetime and alternative buffering agents may also cause unexpected problems (e.g. higher O2 evolution). Would still require SD No Potential alternative electrolytic processes 8 Two-cell Unavailable for Would eliminate the Better separation of From an engineering Theoretically feasible; Yes electrolytic chlorate manufacture; use of SD and the electrodes and gases perspective feasible however, not without systems unknown future presence of Cr(VI) in and lower product but requires a new disadvantages and the electrolyte impurities but poorer plant; very costly and extremely costly current efficiency time-consuming; increased energy consumption can be calculated

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 81 Based on the above findings and using expert judgement, some of the identified alternatives can be excluded from further consideration:

 Rare Earth Metal salts (due to their poor solubility)  Ruthenium-based cathode coatings (as they could not reduce or eliminate the use of/exposure to Cr(VI))  Zirconium-based cathode coatings (as their industrial scale-up has failed in the past and they cannot guarantee the elimination of SD use), and  Ru-based alloy cathodes (as they are found to be fraught with uncertainty and unable to reduce or eliminate the use of/exposure to Cr(VI)).

In conclusion, the following alternatives are considered – in principle – realistic and will be assessed further in Section 5 of this AoA:

 Alternative 1 (substance): Chromium (III) compounds (CrCl3),for completeness, given the lack of suitability in eliminating Cr(VI) exposure  Alternative 2 (substance): Sodium molybdate  Alternative 4 (technology): Molybdenum-based cathode coatings, and  Alternative 8 (technology): Two-compartment electrolytic systems.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 82 5 Suitability and availability of possible alternatives

5.1 Introduction

As mentioned earlier, the preparation of the analysis of alternatives for SD in the manufacture of sodium chlorate has been undertaken by an independent third party on behalf of the consortium, but the AoA for each applicant has been generated individually. As a result, the analysis below includes the following elements:

 Analysis which applies equally to all applicants within the SDAC, including the submitter of the present document. This has to a great extent been based on publicly available information  Where available and appropriate, applicant-specific information has been included. This may include areas where the applicant needs to deviate from the joint analysis in order to explain their particular situation or the feasibility of an alternative for example, or where the applicant is able to provide additional company-specific, thus invariably commercially sensitive, information.

It must be therefore clear that some overlap between this AoA and the AoA documents of the other members of the SDAC should be expected. On the other hand, it needs to be remembered that each member of the consortium may have different needs and access to alternative technologies. This means that the information available to each consortium member company regarding each specific alternative and the detail of the assessment varies by necessity 5.2 Chromium(III) chloride

5.2.1 Substance ID and properties

Table 5-1 presents the identity of chromium (III) chloride which is used here as a representative Cr(III) compound.

Table 5-1: Identity of chromium(III) chloride Properties Chromium(III) chloride Chromium(III) chloride hexahydrate EC Number 233-038-3 919-095-3 / 919-229-0 CAS Number 10025-73-7 10060-12-5 IUPAC Name: Chromium(III) chloride Chromium(III) chloride hexahydrate

Formula CrCl3 CrCl3·6H2O Molecular weight 158.36 266.48

Structure

Source: Chemspider Internet site (http://www.chemspider.com)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 83 Table 5-2 provides an overview of the physicochemical properties of chromium(III) chloride.

Table 5-2: Physicochemical properties of chromium(III) chloride Value Property Notes Anhydrous Hexahydrate Physical state at 20 °C Purple hexagonal plates1 Green monoclinic crystals1 and 101.3 kPa Melting/freezing point 1152 °C1 83 °C2 Boiling point 1300 °C1 No data Density 2.873 1.784 At 25 °C Slightly soluble Soluble5 Hygroscopic1 Water solubility 7.12 g/L6 585 g/L7 Auto-flammability No data No data Flammability No data No data Explosiveness No data No data Oxidising properties No data No data Granulometry No data No data Sources: 1: CRC (2003) 2: Alfa Aesar: http://www.alfa.com/en/catalog/42113, accessed on 29 September 2014 3: Sigma-Aldrich: http://www.sigmaaldrich.com/catalog/product/aldrich/450790, accessed on 29 September 2014 4: Sigma-Aldrich: http://www.sigmaaldrich.com/catalog/product/aldrich/27096, accessed on 29 September 2014 5: Alfa Aesar: http://www.alfa.com/en/GP100W.pgm?DSSTK=42113, accessed on 20 August 2014 6: EPISuite: http://www.chemspider.com/Chemical-Structure.23193.html, accessed on 29 September 2014 7: http://en.wikipedia.org/wiki/Chromium(III)_chloride, accessed on 29 September 2014

5.2.2 Technical feasibility

Assessment of technical feasibility

The use of chromium compounds at a lower oxidation state than 6+ is an approach that has been recently developed to reduce exposure to Cr(VI), however it does not eliminate Cr(VI) from the process. Instead, Cr(III) salts act as a source of in-situ generated SD (by “SD” it is here meant several forms of Cr(VI), depending on the pH value, as per equations (8) and (9) in Section 2.1.2, so that the overall presence of Cr(VI) is equivalent to an effective SD concentration of 3-6.5 g/L). Potential worker exposure to Cr(VI) is marginally lower due to elimination of handling neat SD at the dosing stage. Because Cr(VI) is intended to be present in the system at a similar concentration to the applied for use of SD, it has the potential to fulfil the technical feasibility criteria and on this basis, it might be expected that the changes to the process that would need to be made might be less complex in comparison to other alternatives. Yet, as the applicant does not have access to the details of the technology (currently under patent application filed by a competitor), there is uncertainty over the robustness of this assessment. Table 5-3 summarises the use of chromium(III) chloride according to the technical feasibility criteria.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 84 Table 5-3: Comparison of chromium(III) chloride and sodium dichromate according to technical feasibility criteria Result or value achieved Technical feasibility Criteria pass? Sodium Chromium(III) criteria Threshold * dichromate chloride Formation of protective film permeable to H Expected similar to 2 Sufficient Similar to SD () and impermeable to SD hypochlorite pH buffering and control pH 6.0-6.5; <2.5% pH 6.0-6.5; <4.0% Expected similar to () of oxygen formation O2 O2 in H2 by volume SD Cathode protection Minimum cathode Expected similar to Sufficient () (corrosion inhibition) lifetime: 8 yrs SD Current efficiency and '''#A#'''%; 5,230 >'#A#'%; <5,700 Expected similar to () energy consumption kWh/t theoretical kWh/t SD Sufficient; soluble Solubility in electrolyte Highly soluble Sufficient () in water** Each impurity must be considered Impurities in chlorate <5ppm Cr in solid separately. Metals Expected similar to () product chlorate product are particularly SD detrimental to ClO2 generation * parentheses indicate uncertainty over the conclusion reached due to lack of data ** information from http://www.alfa.com/en/GP100W.pgm?DSSTK=42113 (accessed on 20 August 2014)

Overall, Cr(III) compounds might be considered technically feasible alternatives for SD on the basis of the similarities between these substances and SD but they do not eliminate the presence of Cr(VI) anions in the electrolyte.

Conclusion and required steps to make the alternative technically feasible

To a certain extent, chromium(III) chloride might be considered a replacement for SD as it marginally reduces potential worker exposure at the dosing stage, but this remains to be proven and the applicant has no specific knowledge of the conditions and parameters of the use of the substance.

To implement this alternative, the applicant would need to:

 Acquire access rights to the relevant patented technology, the patent application of which was submitted in 2012 and has not yet been granted  Introduce yet unknown changes to the existing equipment that would allow the optimisation of the dosing of chromium(III) chloride  Develop in-house company knowledge and expertise, through testing and training of the personnel.

The issue of access to the patent that describes the use of Cr(III) needs to be considered and is discussed further below.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 85 5.2.3 Economic feasibility

The cost of converting from SD to CrCl3 needs to consider both investment costs and changes to operating costs.

Investment costs for the implementation of the alternative

Kemira operates three sodium chlorate production plants in Joutseno (Finland), Sastamala (Finland) and Kuusankoski (Finland). For a conversion of these plants to Cr(III) technology the following costs would be involved:

 Access to technology and R&D: it is understood that a direct competitor, AkzoNobel, has filed an application for the patent protection of the Cr(III) technology (Hedenstedt & Edvinsson- Albers, 2012). This patent application has been published and is subject to examination. Kemira would need to secure access to the patent before implementing this alternative. The terms under which Kemira might be granted access to the technology would be subject to negotiations between the two parties. No further detail on the associated cost can be provided here but the implications of reliance on a direct competitor’s licensed technology must be noted.

 Plant conversion costs: Kemira is not certain of what conversion actions would be required to be undertaken at the Joutseno and Sastamala plants if CrCl3 were to replace SD, whether any production stoppage might be required, what additional equipment might be needed (and what additional running/maintenance cost they would attract) and how easy or quick the optimisation of the dosing stage might be. Given the technical similarities between SD and Cr(III) compounds, the time and cost required could be lower in comparison to the other alternatives discussed in this AoA but it has not been possible to estimate at this stage.

Operating costs

There are many elements that contribute to operating costs, but as already noted, energy is the main cost of the production process. The following table presents the range of different operating cost elements and provides a comparison of the costs arising under SD and under CrCl3. It must be noted that this (and other similar tables shown later in this AoA) represent the average costs across all sodium chlorate plants operated by the applicant. The assumption made is that CrCl3 would be able to generate in the electrolyte the required concentration of SD and that the electrolytic process could proceed as if SD had been dosed. This is an unproven assumption, as the applicant has no access to the particulars of the Cr(III) technology.

Table 5-4: Comparison of operating costs for production of sodium chlorate between SD and chromium(III) chloride Current process cost in € per tonne of Change due to use of Operating cost category sodium chlorate chromium(III) chloride product Energy costs for producing 1 tonne of sodium chlorate Electricity ''''''''''#C#' '''''''''''' No change assumed, as SD is

Gas (made by by-product H2) Minor formed in the electrolyte Materials and service costs for producing 1 tonne of sodium chlorate Cost of SD '''''''''' '''''#D#'''''''

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 86 Table 5-4: Comparison of operating costs for production of sodium chlorate between SD and chromium(III) chloride Current process cost in € per tonne of Change due to use of Operating cost category sodium chlorate chromium(III) chloride product Raw materials (salts, additives, etc., excluding '''''''' '''''''''' ''' '''''''''''''''' No change assumed water and sodium dichromate) ''''''' '''''''''''' Water Minor No change assumed Environmental service costs (e.g. waste Minor No change assumed treatment and disposal services) Transportation of product to customer '''''''' '''''''''''' No change assumed Replacement parts and any other materials ''''' '''''''''''' No change assumed needed for the operation of the plant Labour costs for producing 1 tonne of sodium chlorate Salaries, for workers on the production line ''''''' ''''''''''' No change assumed (incl. supervisory roles) Costs of meeting worker health and safety Minor No change assumed, as SD would requirements (e.g. disposable gloves, masks, be present in the majority of etc.) process steps Maintenance and laboratory costs for producing 1 tonne of sodium chlorate Sampling, testing and monitoring cost (incl. lab Minor No change assumed, as SD would worker cost) still be present Costs associated with equipment downtime for ''''' ''''''''''''' Uncertain, as it will depend on the cleaning or maintenance (incl. maintenance changes to be introduced to the crew costs) plant (new equipment may introduce new maintenance requirements) Other costs for producing 1 tonne of sodium chlorate Insurance premiums ''''''''''''' No change assumed Marketing, license fees and other regulatory ''''''''''' No change assumed, REACH compliance activities Authorisation fees still required due to presence of Cr(VI) Other general overhead costs (e.g. '''''''' No change assumed administration) Overall costs (% change) '''''#C#'''''' '''''''''''' ''''''''''''#D#' '''''''''' '''''''''''''''

Energy: on the assumption of a high degree of technical similarity between the use of SD and the alternative, the cost of energy would be unlikely to change noticeably as a result of transfer to the alternative.

Materials and services: this is where the main operating cost difference might arise, based on the relative cost of the price of chromium(III) chloride in comparison with SD. The following two tables present publicly available price data for SD and CrCl3. It can roughly be assumed that SD is available at €1,540/t while CrCl3 is sold at €2,000/t (median prices, see Table 5-5 and Table 5-6 below), i.e. a 30% increase per tonne. It must be noted that the quality of incoming raw materials is of extremely high importance as any impurity will accumulate in the predominantly closed loop chlorate process.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 87 Prices for approved raw materials may therefore differ from the examples in the table, which are solely used for the purposes of calculating the economic costs of conversion to Cr(III)8.

Table 5-5: Cost of chromium(III) chloride hexahydrate (Alibaba.com, 2 April 2014) Minimum Supply Source Location Purity Order Price (€/t) (FOB) Ability (t/y) Quantity (t) 1 China 98 12,000 1 2,270 2 China 98 6,000 0.001 1,098-2,050 3 China 98 12,000 1 1,908 4 China 99 12,000 1 2,021 5 China 99 12,000 1 3,902 6 China 99 12,000 1 1,830 7 China 99 12,000 1 3,851 Range (€/t) 1,098-3,902 Average price (€/t) 2,479 Median price (€/t) 2,021

Table 5-6: Cost of sodium dichromate dihydrate (Alibaba.com, 2 April 2014) Minimum Supply Source Location Purity Order Price (€/t) (FOB) Ability (t/y) Quantity (t) 1 China 98 10,000 5 1,098-1,464 2 China 99 48,000 3 1,830-2,048 3 China 98.5 60,000 25 1,794-2,013 4 China 98.3 10,000 5 1,098-1,464 5 China 99.5 96,000 1 1,830-2,048 6 China 98-99.3 60,000 1 1,391-1,611 7 China 98 5,000 5 1,501-1,574 8 China 98 2,500 10 1,318-1,464 9 China 98.5 72,000 3 1,830-2,050 10 China 98.3 30,000 5 1,098-1,464 11 China 99 36,000 5 1,830-2,048 12 China 98 35,000 10 1,245-1,464 13 China 98.3 6,000 1 1,464-1,830 Range (€/t) 1,098-2,050 Average price (€/t) 1,610 Median price (€/t) 1,538

8 Kemira may purchase SD at a different price to the one used in the calculations here. This analysis uses the price information available from Alibaba to ensure that it is, to the extent possible, comparable to the Alibaba-sourced prices of the alternatives (chromium(III) chloride and sodium molybdate). Using the actual price paid for by Kemira would make a small difference to the calculations, but not to the overall conclusions of the analysis as the additive represents a very small proportion of the overall production costs.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 88 It is assumed that SD is used at 4.5 g/L of electrolyte (mid-range of 3-6 g/L in the BREF Document) and that sufficient chromium(III) chloride hexahydrate would be used to achieve an equivalent concentration of Cr(VI) in the electrolyte. Taking into account the following molecular weights:

 SD anhydrous: 261.97, SD dehydrate: 297.97  CrCl3 anhydrous: 158.36, CrCl3 hexahydrate: 266.48

The replacement ratio for the hydrated salts SD:CrCl3 is 1:2 and for the anhydrous salts: 1:1.2.

Given the applicant’s consumption of anhydrous SD of ''''#B#'''' kg/t sodium chlorate, the consumption of anhydrous CrCl3 would be '''''#G#''''' kg per tonne of sodium chlorate. This would be equivalent to a production cost increase of €''''#D#'''''/tonne sodium chlorate. With an assumed annual production of sodium chlorate of '''''''#B#''''''''' tonnes (with a total nameplate capacity of ''''#B#'''' kt), the additional annual cost from the conversion would be ca. €'''#D#'''/y.

Labour costs: on the assumption of a high degree of similarity between SD and CrCl3, no substantial cost changes would be likely to arise. There is still Cr(VI) in the electrolyte so despite the elimination of handling neat SD, the cost of worker protection will not show any discernible decline.

Maintenance costs: it is unclear whether any cost increases might arise as a result of the introduction of new equipment.

Other costs: it is explained below that the use of a Cr(III) substance that is oxidised to Cr(VI) in the electrolyte would only have a small positive effect to the overall potential exposure of workers to Cr(VI) during the operation of a sodium chlorate plant. Therefore, whilst the use of SD would indeed be eliminated by using the Cr(III) alternative, the source of exposure to the Cr(VI) anion that confers to SD its SVHC properties would largely remain, particularly for inhalation worker exposure. Therefore a conversion to Cr(III) would be an insufficient step towards the removal of the need for a REACH Authorisation. Also, because SD is formed during the use of this alternative, its use would not forego the need to apply for Authorisation.

Conclusion and required steps to make the alternative economically feasible

The investment costs associated with the implementation of this alternative are currently unknown. The changes to the applicant’s plants could possibly be more straightforward and of a lower cost compared to the other alternatives assessed in this AoA, but there will also be a cost for acquiring the rights to use the patented technology (after the patent has been granted) which is currently unknown. The changes to operating costs would be probably be low (assumed above to be an estimated €'''#D#''' per year), excluding any yet uncertain cost increases for the maintenance of any new equipment required.

In light of the existing uncertainties, particularly, the economic feasibility of acquiring a license for using this technology in the future, it is not possible to conclusively assess whether the alternative is economically feasible for Kemira.

5.2.4 Reduction of overall risk due to transition to the alternative

Overview

Appendix 2 (Section 8) to this AoA document presents a detailed analysis of the hazards and risks of the selected potential alternative substances. The reader is referred to the Appendix, while here a

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 89 short summary of findings is presented only. For this alternative, the analysis in the Appendix looks beyond CrCl3 into other Cr(III) compounds to ensure that an adequate dataset has been used in the comparison to SD.

Classification and labelling

For chromium (III) chloride hexahydrate, self-classified notifications according to the classification and labelling inventory suggest a hazard profile more benign than SD (Skin Irrit, Eye Irrit 2, STOT SE 3 (respiratory), Acute Tox 4), see Figure 9-3 in Appendix 2. Other Cr(III) compounds may have different hazard profiles. For example, chromium trinitrate has been classified in its registration dossier as

 Oxidising solid Cat 3 (H272: May intensify fire; oxidiser)  Skin sensitising Cat 1A (H317: May cause an allergic skin reaction)  Acute toxic Cat 4 after inhalation (H332: Harmful if inhaled)  Aquatic Chronic toxic Cat 2 (H411: Toxic to aquatic life with long lasting effects).

Chromium triacetate has been classified as skin sensitising Cat 1B (H317: May cause an allergic skin reaction) in the registration dossier. All three substances are soluble Cr(III) salts and human health hazards are probably due to Cr(III).

Generally, however, when seen in isolation Cr(III) compounds can be considered more benign than SD or other Cr(VI) compounds.

Comparative risk characterisation

Ecotoxicity – PNEC values

Information on the ecotoxicity of Cr(III) compounds is available from registration dossiers, the EU Risk Assessment Report (EU RAR) for Cr(VI) compounds and a Concise International Chemical Assessment Document (CICAD). Appendix 2 explains that the PNECfreshwater as derived within the EU RAR of 4.7 µg Cr(III)/L has been used for the comparative assessment to SD. Additionally, a recalculated PNECSTP of 490 µg Cr(III)/L has been used based on the chromium triacetate dossier.

Mammalian toxicity – DN(M)EL values

Appendix 2 explains that the most critical effects for the evaluation of long-term toxicity of Cr(III) are local effects in the lung seen after inhalation exposure towards soluble Cr(III). Therefore, a tentative DNEL for comparative risk assessment was derived on basis of a 90-day inhalation toxicity study with chromium sulphate in a comparative manner to the procedure described for chromium trinitrate. Starting from a LOAEC of 3 mg Cr(III)/m3 (corresponding to a human equivalent concentration of 1.5 mg Cr(III)/m3) and an assessment factor (AF) of 75, a tentative DNEL value of 0.02 mg Cr(III)/m3 has been calculated for local effects after long term inhalation exposure.

Comparative risk assessment

Appendix 2 shows that the ecotoxicity RCR of CrCl3 is considerably lower than the respective RCR for SD. In addition, the human health RCR is several orders of magnitude lower than the RCR for SD. Although the risk characterisation is based on assumptions for release and exposure calculations are tentative and are not meant to represent real conditions at the applicant’s production sites, use of

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 90 CrCl3 would appear to be beneficial with regard to human health considerations. Under the conditions of use assumed here also the comparative environmental risk characterisation leads to the conclusion that there is less risk associated with the use of the Cr(III) compound. It must be noted that the RCRs for SD are also below 1 both for ecotoxicity and human health toxicity.

Discussion on elimination of exposure to Cr(VI) from the use of Cr(III) compounds

The CSR describes six Tasks for workers, which may result in some exposure to SD, see Table 5-7. Not all Tasks are relevant to all workers exposed to SD during the manufacture of sodium chlorate; instead, realistic shift patterns have been established and are used in the CSR (see Table 5-8). This latter table also presents the estimates of long-term inhalation and dermal exposure of workers under the three different shift patterns or worker roles, during which a variety of tasks might be undertaken.

Table 5-7: Worker tasks (CSR) during which SD (Cr(VI)) exposure may occur Task Description Task 1 Feeding liquid SD solution into the process (PROC 8b) Task 2 Use in closed batch process: Sampling electrolyte solution (PROC 3) Task 3 Laboratory analyses (production lab) (PROC 15) Task 4 Maintenance and cleaning (PROC 8a) Task 5 Waste handling (filter press) (PROC 8b) Task 6 Laboratory analyses (central lab) (PROC 15) Source: CSR, Section 9

Some important points need to be considered (and these need to be seen in the light of the much more detailed analysis presented in the CSR):

 Use of a Cr(III) compound in the place of SD would aim to eliminate exposure during Task 1 (feeding liquid SD solution into the process, i.e. dosing). All other Tasks, in terms of worker exposure to Cr(VI) species, would remain unchanged

 Task 1 is performed by “day workers”. This is a very infrequent task. These workers also carry out Tasks 4 and 5 that may also involve exposure to Cr(VI)

 The CSR provides the exposure estimates for each type of shift pattern. As shown in Table 5-8, the aggregate inhalation exposure for day workers is calculated at 1.23 ng/m3 (long-term TWA). The total exposure for day workers is calculated as T1+T4+T5, however, as there are two workers who share these roles, the exposure is divided by two. The total exposure using sodium dichromate is ((T1+T4+T5)/2 = 0.62 ng/m3 as a long term TWA. When the exposure is recalculated without Task 1, the exposure for day workers becomes ((T4+T5)/2) = 0.495 ng/m3. Therefore, Task 1 (dosing) represents only ca. 20% of the aggregated inhalation exposure.

Conclusion on suitability

In conclusion, whilst the comparative risk assessment of Cr(III) compounds indicates a more benign profile than SD, due to the transformation of Cr(III) into Cr(VI) in the electrolyte, no real reduction in worker exposure would be likely to arise. This of course must not detract from the key conclusion of the CSR that existing risks to worker health are very low (risk characterisation ratio for inhalation

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 91 exposure for day workers is ''''''''''' #H#''' '''''''''' while continuing to use sodium dichromate and that measurements are so low that the measurements process required the use of the newest techniques to be able to determine if there was in fact any exposure at all.

The use of Cr(III) compounds would not be a suitable alternative as the existing (very low) risks from exposure to SD would still largely remain unchanged. The use of Cr(III) compounds cannot be viewed as a viable long-term replacement for SD that would eliminate exposure to Cr(VI).

Table 5-8: Task-specific and aggregated long-term TWA inhalation exposure estimates for unit operators and day workers (CSR) Long-term TWA Cr(VI) Task N N (sites) N

5.2.5 Availability

Three elements of availability can be considered:

 Availability of the alternative in quantities sufficient for the applicant’s production processes  Availability of the alternative in the quality required by the applicant’s production processes  Access to the technology that allows the implementation of the alternative as a SD replacement.

With regard to the quantity required, CrCl3 is not yet registered under REACH (although other Cr(III) compounds have been registered). However, the tonnage of CrCl3 that would be required is very small; previously, it was estimated that Kemira may need '''#D#''' kg of CrCl3 per tonne of sodium chlorate produced. Therefore, the tonnage of CrCl3 required would be well below 10 t/y.

Issues of quality have not been identified.

Finally, with regard to access to the technology required, it has been shown earlier that a process using Cr(III) compounds instead of SD has had a patent application filed by a direct competitor. The patent application is undergoing examination and therefore it may be granted (and consequently might become available for licensing by the patent holder) after a period of notable length which will most likely be after the sunset date.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 92 Conclusion and required steps to make the alternative available

The technology is not currently available to the applicant and will remain unavailable until after the relevant patent has been granted to the competitor who filed the application and thereon only if the license becomes available to Kemira on commercially and economically acceptable terms. It is very unlikely that the situation on availability will change by the sunset date.

5.2.6 Conclusion on suitability and availability for chromium(III) chloride

The most critical disadvantage of chromium(III) compounds is that they cannot be considered suitable. The use of this alternative generates sodium dichromate during the process and so its use would not forego the need to apply for Authorisation. The use of this alternative would eliminate the handling of SD, but overall they would reduce the estimated aggregate worker inhalation exposure for day workers by a factor of only 20% and would make no discernible difference to the current Cr(VI) exposure of other unit operators or laboratory workers. Therefore, they cannot be considered valid alternatives for the purposes of this AoA.

Chromium(III) chloride (and Cr(III) compounds more generally) might be a technically feasible alternative substance to the use of SD, but this is currently uncertain as the applicant does not have access to the particulars of the Cr(III) technology. Similarly, chromium(III) chloride might be economically more feasible than the rest of the alternatives presented in Section 5 of this AoA, but there is uncertainty over the changes that would be required to the applicant’s plant as well as over the economic terms of acquiring a use license from the competitor who has applied for a patent on it. Finally, this alternative is currently unavailable to the applicant, and will only become available in the future if licensed on commercially and economically acceptable terms.

Overall, chromium(III) compounds are not acceptable as replacements for SD in the Applied for Use. 5.3 Sodium molybdate

5.3.1 Substance ID and properties

Sodium molybdate is available in two forms. These are shown in Table 5-9.

Table 5-9: Identity of available forms of disodium molybdate Properties Disodium molybdate Sodium molybdate dihydrate EC Number 231-551-7 600-158-6 CAS Number 7631-95-0 Sodium dioxide(dioxo)molybdenum IUPAC Name: Disodium dioxide-dioxomolybdenum hydrate (2:1:2)

Formula MoO4·2Na Na2MoO4·2H2O Molecular weight 205.92 241.92

Structure

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 93 Table 5-9: Identity of available forms of disodium molybdate Properties Disodium molybdate Sodium molybdate dihydrate Sources: 1: http://esis.jrc.ec.europa.eu/ 2: ECHA dissemination portal: http://apps.echa.europa.eu/registered/data/dossiers/DISS-9eb7d44e-5b59- 695c-e044-00144f67d031/AGGR-d3c96bda-6117-42e7-bf76-918c545cb4f7_DISS-9eb7d44e-5b59-695c-e044- 00144f67d031.html#section_1.1 3: https://upload.wikimedia.org/wikipedia/commons/0/08/Natriummolybdaat.png 4: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=16211258

Table 5-10 provides an overview of the physicochemical properties of disodium molybdate.

Table 5-10: Physicochemical properties of disodium molybdate Property Value Note Physical state at 20°C and Crystalline solid colourless to at 20 °C and at 1013 hPa 101.3 kPa white Melting/freezing point No data Decomposes >100 °C Boiling point - - Density 2.59 at 23.3 °C Water solubility ca. 654.2 g/L at 20 °C at pH 8.8 OECD Guideline 105 (Water Solubility) Auto-flammability Not justified Flammability Not justified Explosiveness Not justified Recommendations on the Transport of Dangerous Goods, Manual of Tests and Oxidising properties No oxidising properties Criteria, Part 34.4.1, Test O.1: Test for oxidizing solids Guideline 67/548(EEC (Council Directive 92/69/EEC) OECD Guideline 110 (Particle Size % ile: D10, Mean: 34.5 µm Distribution / Fibre Length and Diameter Granulometry % ile: D50, Mean: 143.1 µm Distributions) % ile: D90, Mean: 295.9 µm CIPAC MT 187: Particle Size Analysis by Laser Diffraction ISO13320-1: Particle Size Analysis-Laser Diffraction Methods Sources: ECHA dissemination portal: http://apps.echa.europa.eu/registered/data/dossiers/DISS-9eb7d44e-5b59-695c- e044-00144f67d031/AGGR-e8329392-562d-40df-96dc-082576cf46a0_DISS-9eb7d44e-5b59-695c-e044- 00144f67d031.html#AGGR-e8329392-562d-40df-96dc-082576cf46a

5.3.2 Technical feasibility

Assessment of technical feasibility

The use of sodium molybdate as a potential alternative to the use of SD has been proposed due to a combination of its buffering properties and its ability to form a protective film on the cathode. The available information indicates that the use of sodium molybdate has not yet been demonstrated on a commercial scale and that academic R&D efforts have identified significant limitations.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 94 Important differences with SD have been found that influence the ability of sodium molybdate to meet the technical feasibility criteria, as shown in the available scientific literature. In general, sodium molybdate is lacking in performance, in comparison to SD and this has led some researchers to trial the use of sodium molybdate in parallel with reduced amounts of SD with the aim of achieving the required process parameters. As the aim of the alternative in this case is to eliminate SD, the comparison between sodium molybdate and SD that is shown in Table 5-11 has been carried out assuming no SD is present. Once again, the reader is reminded that this comparison has been jointly generated for the members of the SDAC, but where applicant-specific information is available, this has been used to ‘overrule’ the more generic analysis.

Table 5-11: Comparison of sodium molybdate and sodium dichromate according to technical feasibility criteria Technical Result or value achieved Criteria pass? feasibility criteria Sodium dichromate Threshold Sodium molybdate Formation of It creates a protective protective film that film but published is permeable to Sufficient Similar to SD research suggests it  hydrogen and grows too quick and is impermeable to potentially unstable hypochlorite pH 5.0-6.0; O in H pH buffering and 2 2 pH 6.0-6.5; <2.5% pH 6.0-6.5; <4.0% 3.6-4.8% control of oxygen  O O in H by volume Additional buffer is formation 2 2 2 required Cathode protection Minimum cathode Unknown (laboratory (corrosion Sufficient ? lifetime 8 years scale only) inhibition) Current efficiency 86% current ''''#A#''''%; 5,230 >''#A#'''%; <5,700 and energy efficiency; 5,746  kWh/t theoretical kWh/t consumption kWh/t theoretical Solubility in 654.2 g/L Highly soluble Sufficient  electrolyte Sufficient Each impurity must be considered Presence of metal Impurities in <5ppm Cr in solid separately. Metals (Mo) impurities would  chlorate product chlorate product are particularly act as a ClO2 process detrimental to ClO2 ‘poison’ generation

Overall, the comparison suggests that sodium molybdate meets one criterion, under the current state of knowledge, fails four criteria and for a sixth criterion no conclusion can be reached on the basis of available information.

Detailed presentation of technical characteristics of the alternative

Formation of a protective film: the substance is capable of forming a protective film around the cathodes; however, its thickness may grow excessively quickly, thus affecting the efficiency of the electrochemical reactions by increasing energy consumption. In comparison, the dichromate film only grows to a certain extent (it is self-limiting) depending on current density and chromate content. Also, as discussed in Section 4.2.3, the presence of phosphates (the necessity of which is discussed below) interfered with the formation of the molybdate film. At high Mo concentrations,

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 95 80 mM molybdate in the electrolyte, a cracked film was formed on the cathode surface. If the amount of molybdate in the lab tests was low (4 mM) and the electrolyte also contained between 10 and 40 mM phosphate no molybdenum film was visible with Scanning Electron Microscopy (SEM) or detectable with Energy-dispersive X-ray spectroscopy (EDX) on the cathode surface. Generally, there are great uncertainties surrounding the technical feasibility of sodium molybdate and the applicant does not have first-hand experience with the alternative, even at the lab scale. pH buffering and oxygen formation: the ability of sodium molybdate to function as a pH buffer in the region required for the chlorate reaction (see Section 2.1.1) is limited and may require the addition of an additional phosphate buffer. However, such an addition would cause very serious technical problems. While typically a maximum of 5 mg PO4/L cell solution can be acceptable, the concentration that might be required if sodium molybdate were to replace SD would be 4.9 g/L, i.e. ca. 1,000% higher than what is currently assumed acceptable. Several problems might arise from the addition of a phosphate buffer at such high levels:

 Side reactions at the anode: phosphates would cause precipitations on the anode surface in the presence of Fe and Si, potentially leading to a failure of the coating of the anodes. The durability of the anodes would be seriously compromised in the presence of 4.9 g/L phosphates under normal conditions of use. This has been documented in the scientific literature; for example, Krstajić et al (1984) have documented that the standard mixed RuO2·TiO2 coated titanium anodes deteriorates very quickly in the presence of ionic phosphate species (and go on to recommend the development of a different type of anode containing palladium and tin oxides in the coating mixture which are not currently state of the art). Such high concentration may have been suitable for lab experiments such as those described in the patent literature but these are typically very short and not representative of the continuous operation of a chlorate plant  Increase in the release of oxygen: literature suggests that deposits on the anode associated with phosphate impurities in the brine cause an increase in production of oxygen at plant scale9 (Kus, 2000)  Increased maintenance requirements: acid washing of the electrolysers would need to be undertaken more frequently to maintain efficiency in the process  Higher energy consumption: the above adverse effects would result in an increase to the consumption of electricity during the electrolysis.

Overall, the use of phosphates at the required concentration is technically a “non-starter” under the current technological knowledge and with existing anodes. In this regard, the remainder of the discussion on the technical feasibility of sodium molybdate is largely theoretical and academic.

Meanwhile, molybdate itself also causes higher levels of oxygen production, thus increased concentration of oxygen in the hydrogen gas stream, far higher than what is possible to achieve when using SD. This represents a serious process safety concern related to the risk of explosion. For these reasons, the use of both molybdate and phosphate should ideally be as low as possible.

If the oxygen generation increased in comparison to the present SD-based technology to a level that would pose a safety risk (and this would indeed be the case with an oxygen concentration in hydrogen of 3.6-4.8%), action would need to be taken to dilute the generated gas. This could

9 The effects have been found to affect large scale production in very low levels of phosphate (down to 1-5 ppm) but short duration laboratory scale trials had not reproduced the effect (Nylén & Cornell, 2006).

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 96 include a nitrogen purge, a fairly well established method of dilution. However, operation of the plant with a continuous purge of nitrogen to decrease oxygen concentration below the explosion limit would pose significant problems:

 Additional instrumentation would need to be introduced  #A#    The amount of nitrogen required would be significant, possibly in the range of hundreds of kilograms (''''''#A#'c'''''') per tonne of NaClO3 (depending on the dilution factor)  The use of the H2/N2 mixture in reactions where H2 is needed as a raw material, would be impossible, particularly as the flow of variable content H2/N2 mixtures cannot be measured. The presence of nitrogen limits the purity of the hydrogen, and compressing and using the hydrogen when it contains high amounts of nitrogen would be technically very challenging.

For Kemira’s plants where the hydrogen is used for ancillary operations, the use of nitrogen purging would impact on the applicant’s ability to use the generated hydrogen. In Sastamala, hydrogen is used for the manufacture of sodium borohydride. In Joutseno, HCl is manufactured from by-product hydrogen from both the chlorate plant and the nearby chlor-alkali plant.

Cathode protection: the long-term effect over multiple years on cathode protection is not known due to lack of large-scale trials outside of the laboratory.

Current efficiency and energy consumption: publicly available information suggests that when sodium molybdate is used, in the absence of any Cr(VI) in the electrolyte, it is unlikely that a current efficiency above 80-91% could be achieved (Li et al. (2007); Gustafsson (2012)). If a mid-range value of 86% were to be assumed, the loss of efficiency relative to SD would be significant and technically infeasible, as the current efficiency would be below ''#A#''. The total theoretical anticipated energy consumption would be 5,746 kWh/t of chlorate produced10.

Impurities in the chlorate product: the use of sodium molybdate is likely to result in traces of Mo in the chlorate product, in a similar fashion that Cr traces can presently be found in the chlorate (less than 5 ppm, see Table 2-5). This is certainly a cause for concern; whilst presence of chromium in the chlorate product does not affect the customers’ processes (ClO2 generation), a metal such as Mo would act as a ‘poison’ to the ClO2 manufacturing process. Therefore, the use of sodium molybdate might cause unnecessary and unwelcome problems to the applicant’s customers.

10 The following conditions for a chlorate cell employing SD were used to enable a comparison to be made to a theoretical change to sodium molybdate. A cell voltage of 3.1 V (mid-range value from BREF (IPPC, 2007)) and current efficiency of 95% gives a theoretical energy requirement of 4,930 kWh/tonne of chlorate + 300 kWh/tonne (mid-range value for other electrical equipment) = 5,230 kWh/tonne chlorate using SD. Using sodium molybdate, the literature indicates a current efficiency in the range 80-91% efficiency. Using the mid-range value of 86% and the same cell voltage, an electrical consumption of 5,446 kWh/tonne can be calculated + 300 kWh/tonne = 5,746 kWh/tonne of chlorate or a 9.9% increase in electrical consumption.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 97 Conclusion and required steps to allow use of sodium molybdate as an alternative to sodium dichromate

As shown above, poor pH buffering, increased oxygen formation, impaired current efficiency and unwanted metal impurities are the key issues faced by sodium molybdate. While the addition of a phosphate buffer would address the issue of pH, it would seriously impact upon anode performance (Kus, 2000) and would further increase in oxygen formation, thus affecting the stability and economics of the electrolysis process. The addition of phosphates at the high concentrations described in the patent literature make this alternative entirely infeasible.

The most practical way of addressing these problems may be to introduce SD at a lower level (<3 g/L) in combination with a lower level of molybdate without the presence of phosphate. However, the use of SD would still require a REACH Authorisation, thus this cannot be a realistic solution to the problems faced by sodium molybdate.

Consequently, for sodium molybdate to be considered a viable replacement for SD, further research will be needed in order to improve its identified shortcomings. Elements of further R&D might include the following:

1. R&D phase in existing electrolyte to verify robustness

2. R&D to optimise the mixture of molybdate and phosphate

3. R&D to scale-up to (a) long-term tests, lab pilot (b) intermediate scale, (c) commercial scale

4. Possible change from steel cathode to alternative dimensionally stable cathode technology

5. Replacement of the existing Cr(VI) containing electrolyte solution with newly developed electrolyte

6. Implementation of additional safety measures to decrease oxygen concentration to an acceptable level (such as a hydrogen DeOxo plant (BASF, 2014) and/or use of inert gas).

7. Implementation of systems for gas treatment to ensure clean-up of hydrogen before further use.

The applicant is aware of R&D on molybdate additives in chlorate production that has already taken place by third parties and that the reduction and removal of Cr(VI) from the chlorate process through the use of molybdates has been the goal for more than a decade. Only limited progress has been made so far towards the total removal of Cr(VI) from the process but potential reductions in the level of Cr(VI) have been suggested. The applicant assumes that, in order to make significant gains to a commercially feasible alternative using this technology, substantial further R&D will be required. This would then need to be followed by process scale-up trials before commissioning any changes required to existing plant technology.

5.3.3 Economic feasibility

This alternative has been found to be technically infeasible to implement. Therefore it cannot be considered economically feasible for the applicant.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 98 Appendix 3 describes the implications for the applicants if the technical feasibility is ignored and the costs calculated based on the claimed performance of the alternatives. This is provided for sake of clarity.

5.3.4 Reduction of overall risk due to transition to the alternative

Overview

This sub-section presents a comparison of risks from the alternative and SD with regard to worker exposure during the manufacture of sodium chlorate and further estimates and monetises the environmental impacts arising from the increase in energy consumption that would arise from the replacement of SD with the alternative.

Appendix 2 (Section 8) to this AoA document presents a detailed analysis of the hazards and risks of the selected potential alternative substances. The reader is referred to the Appendix, while here a short summary of findings is presented only. For this alternative, the analysis in the Appendix looks not only into sodium molybdate but also sodium phosphates which might be used as pH buffers alongside the molybdate salt.

Classification and Labelling

Sodium molybdate does not have a harmonised classification under CLP (EC No 1272/2008). In the C&L inventory a total of 13 aggregated notifications have been identified. Most commonly, no classification is notified followed by the classes presented in Figure 9-4 in Appendix 2.

Appendix 2 explains that while sodium molybdate(VI) dihydrate is a possible alternative to sodium dichromate, also data on sodium molybdate(VI) (anhydrous, CAS: 7631-95-0) are reported as toxicity is independent from water of hydration. Where toxicity is related to elemental Mo, no explicit reference is made in every instance to what exactly was the species used in the test.

On the other hand, sodium phosphates have been looked at as required additives alongside the molybdate. Appendix 2 looks at disodium hydrogen orthophosphate (CAS No. 7558-79-4) and sodium dihydrogen orthophosphate (CAS No. 7558-80-7), both of which are in equilibrium with each other in aqueous solution and the state of equilibrium solely depends on the pH of the solution. Therefore, they have been assessed together.

For sodium phosphates, no Harmonised Classification according to Annex VI of the CLP Regulation is available. In the registration dossiers of both substances, no classification has been recommended. For disodium hydrogen orthophosphate and sodium dihydrogen orthophosphate, classification according to the classification and labelling inventory is shown in Figure 9-5 in Appendix 2.

According to their respective joint entries (REACH registration), these compounds are not classified.

Comparative risk characterisation

Ecotoxicity – PNEC values

Information on PNEC values for sodium molybdate is available from the ECHA Dissemination Portal (ECHA-CHEM). A PNECfreshwater of 12.7 mg/L (based on elemental Mo) and a PNECSTP of 21.7 mg/L (based on elemental Mo) have been used in the assessment of alternatives to SD.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 99 PNEC values for the two sodium phosphates have also been obtained (PNECfreshwater: 100 µg/L, PNECSTP: 100 mg/L). However, in acute aquatic toxicity tests with sodium phosphates (sodium dihydrogen orthophosphate and disodium hydrogen orthophosphate) up to the limit concentration (100 mg/L) no toxic effects were observed and comparing real phosphate concentrations with the PNECfreshwater will always result in RCRs > 1. Taking into account, that huge amounts of phosphate are released into the environment by use of inorganic fertilisers and that phosphates are excreted from the human body, a further quantification of phosphate exposure in the context of this use has not been performed as the total amount released into the environment from this use is regarded as negligible in comparison to the other phosphate sources.

Mammalian toxicity – DN(M)EL values

Based on the data documented in Appendix 2 a tentative DNEL for systemic effects after long-term inhalation exposure was derived for molybdenum(VI) on basis of a 90-day repeated dose inhalation toxicity study performed with molybdenum trioxide (66.7 mg Mo(VI)/m3: NOAEC systemic effects). As there is no evidence for local effects after inhalation exposure, no such tentative DNEL is derived. The tentative DNEL value for systemic effects after long term inhalation exposure used for the comparative assessment is 1.3 mg Mo(VI)/m3.

For phosphates, the tentative DNEL was derived by route-to-route extrapolation on basis of a 90-day repeated dose oral toxicity study with sodium aluminium phosphate in dogs (NOAEL of 322.88 mg/kg bw/day). Appendix 2 explains that the extrapolation results in a tentative DNEL for systemic effects after long-term inhalation exposure of 32.29 mg sodium aluminium phosphate/m3 corresponding to 21.1 mg phosphate/m3 or 6.9 mg phosphor/m3.

Comparative risk assessment

Appendix 2 shows that the ecotoxicity RCR of sodium molybdate is far lower than the respective RCR for SD. In addition, the human health RCRs for both the molybdate and the phosphates are several orders of magnitude lower than the RCR for SD. Although the risk characterisation is based on assumptions for release and exposure calculations are tentative and are not meant to represent real conditions at the applicant’s production sites, use of sodium molybdate in combination with phosphate buffer would appear to be beneficial with regard to human health considerations. Under the conditions of use assumed here, the comparative environmental risk characterisation leads to the conclusion that there is less risk associated with the use of the molybdate compound. Again, it must be noted that the RCRs for SD are also below 1 both for ecotoxicity and human health toxicity.

Externalities from energy usage

The use of sodium molybdate is expected to increase the energy consumption of the process by considerable amount due to a lower current efficiency and due to the need to acquire energy from external sources to compensate the loss of H2. We therefore calculated the following increases in the releases of greenhouse gases:

 Greenhouse gas emissions from lower current efficiency: as described in Section 5.3.2, an additional 5,746 – 5,230 = 516 kWh/t chlorate produced of electricity is required. Considering the applicant’s annual production of ''''''#B#''''' tonnes, this equates to an additional ''''''#G# ''''''' kWh per year. Using greenhouse gas emission factors available from UK Department for

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 100 Environment, Food and Rural Affairs11, it can be calculated that the generation of the equivalent 12 amount of electricity would result in the release of ''''''#G#''''' tonnes of CO2e per year  Replacement of heat generated with H2 by natural gas: the H2 used by Kemira generates ''''#C#'''' MWh/y for heating purposes. The generation of this energy from the burning of natural 13 gas would result in the following CO2 releases: ''''' '#C#'''''' kWh/y × 0.205526 = '''#G#'' t CO2e/y  Replacement of electricity in Joutseno: Kemira uses H2 in Joutseno to generate X#C#X MWh/y in electricity. Using greenhouse gas emission factors available from UK Department for Environment, Food and Rural Affairs, it can be calculated that the generation of the equivalent amount of electricity would result in the release of ''''#G#'''' tonnes of CO2e per year.

The overall volume of additional CO2 releases is estimated at ''''''''''''' '' '''''''''''''' ''#G#' ''''''''''' ''' '''''''''''' tonnes of CO2e per year (for an additional energy demand of ''''''' '''''''''''' ''' ''''''' ''''#C#''''' '' ''''''' ''''''''''''' ''' '''''''''' kWh/t sodium chlorate).

Monetisation of greenhouse gas emissions is based on the methodology developed by the UK government for carbon valuation in public policy appraisal14. The shadow price of carbon is closer to what would be the full social cost of carbon emissions in terms of the damages caused by carbon emissions, but also takes into account estimates of marginal abatement costs, etc. Thus, it also takes into account policy commitments and technological issues. The value used in this assessment is £31/tonne CO2 for the year 2017 (year of the sunset date), as shown in the relevant UK Government document15. The present day exchange rate (£1 = €1.25) was used to convert the value in £ to € (€38.8/t).

Therefore, the externalities of the increased energy consumption and concomitant CO2 emissions would be ''''''''''''' ''' ''#G#''' ''' '''''' '''''''' million per year.

Other environmental impacts

Hydrogen that could no longer be used in ancillary operations would have to be vented to the atmosphere. Hydrogen is an indirect greenhouse gas (IPCC, 2007).

11 Available at: http://www.ukconversionfactorscarbonsmart.co.uk/, accessed 29 September 2014.

12 The DEFRA 2013 overseas electricity generation factor of 0.22948 kg CO2e/kWh of electricity for Finland was used. Using this factor, the generation of XXX#G#XX kWh of electricity would generate an additional emission of XX#G#X tonnes of CO2e per year.

13 Factor for net calorific value, available at: http://www.ukconversionfactorscarbonsmart.co.uk, accessed 24 November 2014.

14 Available at https://www.gov.uk/government/publications/updated-short-term-traded-carbon-values- used-for-uk-policy-appraisal-2014 (accessed on 13 December 2014).

15 Shadow value of carbon, available at https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/243825/background.pdf.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 101 Conclusion on suitability

Sodium molybdate when used alongside a phosphate buffer is a more benign substance than SD. The substance is considered to be a suitable alternative for SD in the applied for use. However, its use would require additional energy, thus would result in an increase in CO2 emissions to the tune of '''''#G#''''''' t/y.

5.3.5 Availability

Three elements of availability can be considered:

 Availability of the alternative in quantities sufficient for the applicant’s production processes  Availability of the alternative in the quality required by the applicant’s production processes  Access to the technology that allows the implementation of the alternative as a SD replacement.

With regard to the quantity required, Table 5-12 summarises the available information on the status of REACH Registration for disodium molybdate.

Table 5-12: REACH registration status of disodium molybdate Status Tonnage band Date of search Registered 100 – 1,000 tonnes per annum 27 March 2013 Sources: ECHA Dissemination Portal: http://apps.echa.europa.eu/registered/data/dossiers/DISS-9eb7d44e- 5b59-695c-e044-00144f67d031/DISS-9eb7d44e-5b59-695c-e044-00144f67d031_DISS-9eb7d44e-5b59-695c- e044-00144f67d031.html

The tonnage of sodium molybdate that would be required is very small; previously, it was estimated that Kemira may need '''#D#''' kg of sodium molybdate per tonne of sodium chlorate produced. Therefore, the tonnage of sodium molybdate required would be well below 10 t/y.

Issues of quality have not been identified.

Finally, with regard to access to the technology required' ''''''' ''''''''''''''''' '''''' #E#'''''' '''''''''''''''''''''''' ''''' ''''' ''''''' '''''''' '''' '''''''''''''''''''''' '''' ''''''' '''''''''''''''''''''' '''' ''''''''''''''' ''''''''''''''''' ''''' '''''''''' ''''' ''''''' '''''''''''''' '''' ''''''' '''''''''''''' ''''' '''''. As already explained, the required technology that would render this alternative feasible is not currently available.

5.3.6 Conclusion on suitability and availability for sodium molybdate

Sodium molybdate was investigated as an alternative substance that would replace the use of SD in the production of sodium chlorate. The substance (used in combination with a phosphate buffer) is a suitable alternative as it has a more benign hazard profile than SD. The comparative risk assessment performed for the purposes of this AoA suggests a lowering of risk from the replacement of SD by the molybdate salt. Nevertheless, environmental impacts from an increased release of CO2 are to be expected as a result of increased electricity consumption.

It was found that sodium molybdate fails the majority of the technical feasibility criteria and its poor pH buffering capabilities necessitate the addition of phosphate buffers at concentrations much higher than the electrolysis cell can tolerate. It is particularly the addition of phosphates that render this alternative unrealistic: their presence in the electrolysis cells is currently kept at a minimum

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 102 level and if addition of several g/L would be required, the stability and durability of the anodes would be severely impacted.

In addition, sodium molybdate would result in the generation of excessive volumes of oxygen in the hydrogen co-product at levels close to the explosion limit. The presence of phosphates would exacerbate the generation of oxygen. This would raise serious safety risks and would necessitate the introduction of processes that would allow the dilution of the generated gas mixture, typically by means of nitrogen purging.

In terms of economic feasibility, the implementation of sodium molybdate would require significant (one-off) investment costs, including the costs of developing or acquiring access to the relevant technology (when and if this materialises in the future), the disposal of the existing electrolyte and the generation of new electrolyte, the losses of chlorate sales and economic impacts on ancillary operations from the stoppage of the production during conversion, and the cost of introducing/expanding oxygen controls. These costs are substantial and unjustifiable, in light of the lack of technical feasibility of the alternative. Therefore, the use of sodium molybdate cannot be considered economically feasible to the applicant.

Finally, in terms of availability, the molybdate substance itself is available on the EU market; however, the technology that would allow its implementation under conditions that would guarantee a minimum level of technical feasibility and economic viability is not available.

Overall, sodium molybdate has not been found to be a technically or economically feasible alternative to the use of SD in the applicant’s production of sodium chlorate. Even if significant further R&D were to overcome the technical barriers, its economic feasibility would be unlikely to substantially improve. In practice, already extensive R&D presented in the open literature indicates that this is only likely if it is employed alongside a reduced level of Cr(VI). 5.4 Molybdenum-based coatings

5.4.1 Description of alternative technology and properties

This alternative technology involves the use of cathodes that have been coated with molybdenum prior to use in the chlorate process. The aim of the coating is to improve the current efficiency of the process by providing a coating to supress parasitic reactions that can occur during the process, as described in Section 2.1.2. The patents describing the use of molybdenum-coated cathodes are summarised in Section 4.2.3. These patents indicate that molybdate salts (such as those shown in Table 5-9), would be required initially to prepare the coated-cathodes but they would not be added into the process electrolyte afterwards. As a result of this, the buffering effect provided by the presence of sodium molybdate will not be present and will entirely need to be replaced with another agent. The Rosvall et al (2009) patent continues to use SD in the process while the Krstajic et al (2007) patent application replaces the buffering effect of SD using sodium acid phosphates. Therefore, the analysis of the technical feasibility of this alternative assumes that sodium acid phosphates are required if this alternative is being employed without the presence of Cr(VI) in the process.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 103 5.4.2 Technical feasibility

Assessment of technical feasibility

Research into molybdenum-based coatings for chlorate cathodes has focused more on increasing current efficiency than reduction of SD content in the electrolyte. However, some patents nonetheless claim no SD content, and therefore the analysis below has been carried out assuming this can be achieved.

A comparison of technical performance of molybdate-coated cathodes to the identified technical feasibility criteria is shown in Table 5-13.

Table 5-13: Comparison of molybdenum-based coatings and sodium dichromate according to technical feasibility criteria Result or value achieved Technical feasibility Sodium Molybdenum- Criteria pass? * criteria Threshold dichromate based coatings Uncertain: Formation of different protective film that is technology to SD. permeable to The film is not Sufficient Similar to SD () hydrogen and formed impermeable to electrolytically but hypochlorite imposed as a coating Separate pH buffering and phosphate buffer pH 6.0-6.5; <2.5% pH 6.0-6.5; <4.0% control of oxygen required; uncertain  O O in H by volume formation 2 2 2 effect on oxygen concentration Uncertain: lab tests are generally very short and not Cathode protection Minimum cathode Sufficient representative of ? (corrosion inhibition) lifetime 8 years continuous operation at the industrial scale Current efficiency ''''#A#''''%; 5,230 >'#A#'%; <5,700 94%; 4,342 kWh/t and energy () kWh/t theoretical kWh/t theoretical consumption Solubility in Not relevant to this Highly soluble Sufficient Not relevant electrolyte technology Each impurity must Uncertain: be considered presence of metal Impurities in chlorate <5ppm Cr in solid separately. Metals (Mo) impurities () product chlorate product are particularly would act as a ClO detrimental to ClO 2 2 process ‘poison’ generation * parentheses indicate uncertainty over the conclusion reached due to lack of data. A tick is given only if the entire criterion is met

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 104 Detailed presentation of technical characteristics of the alternative

Formation of protective film: the technology differs in that the film is not formed electrolytically but imposed as a coating on the electrode substrate. The evidence available from past R&D is not sufficient to conclusively confirm the technical equivalence of this technology.

Kemira has R&D experience with Ru-coated cathodes, and this has shown that coatings tend to disintegrate/get damaged during production shutdowns, e.g. for maintenance. The applicant has run trials with Ru-Al-Fe for two years and these suggest that, while coatings work when the process is running, when production stops and the cathode is exposed to liquids, most likely coating will decompose during stoppage. The applicant does not thus believe that molybdenum-based coatings would be any different in this regard. pH buffering and control of oxygen formation: the relevant embodiment of the patent application avoids the use of SD but requires phosphate as a buffer. As discussed in Section 5.3.2, the presence of phosphate in the electrolyte is of concern because it can result in increased oxygen levels. The patent, however, does not discuss the level of oxygen achieved. Therefore, taking these factors into consideration, this alternative seems unlikely to fulfil this technical feasibility criterion, although further R&D would be required to determine this conclusively.

Cathode protection: cathode durability would be a concern. The patent applications describing the use of this alternative reference tests lasting four (Rosvall, et al., 2009) or eight hours (Krstajic, et al., 2007), and no long-duration trials are known. Therefore, the effect of this technology on long term corrosion inhibition and cathode lifetime is highly uncertain. Long-duration pilot plant trials would be required to establish the likely rate of corrosion.

Impurities in chlorate product: the effect of transfer to this alternative on the purity of the resulting sodium chlorate is not known due to the lack of pilot scale trials. It seems probable that chlorate purity could be linked, in large part, to any corrosion observed and on the presence of any additive other than chromium that may be used to take over any of the roles of SD in the process. As discussed earlier in relation to sodium molybdate, traces of Mo in the chlorate product could be a cause for concern, since heavy metals are considered as “poison” in the ClO2 manufacturing process. Therefore, the use of molybdate coatings might cause unnecessary and unwelcome problems to the applicant’s customers.

On the other hand, the use of this technology could in theory have notable benefits in comparison to the use of SD-based cells, on the basis of published test results.

Current efficiency and energy consumption: according to the patent application by Krstajic et al (2007), lower cell voltages and hence lower energy consumption can be achieved using molybdenum-based cathode coatings. In the patent, a cell voltage of 2.50-2.53 V with a current efficiency of 94% is implied. Yet, the patent application examples are run over a very short period of time, 8 hours. After such short a period of time, corrosion of the electrodes may not be apparent. As noted by Kus (2000), phosphate may cause negative effects at the anode. These may only become apparent after longer periods of operation time as would be expected in a commercial setting. However, if the results indicated by the patent are used for the sake of a conservative estimate, a theoretical energy consumption of 4,042 kWh per tonne of chlorate can be calculated for the electrolysis. This results in a theoretical energy consumption of 4,342 kWh per tonne of chlorate,

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 105 assuming 300 kWh/t is required for ancillary equipment, representing a considerable decrease in electrical consumption relative to the use of SD16.

Although promising, the publicly available information does not provide sufficient guarantee that these limited results can translate to energy savings at the industrial scale and, to the best of the applicant’s knowledge, this technology has not come any closer to commercialisation. Kemira does not consider molybdenum-based cathode coatings to be a realistic technically feasible alternative to the use of SD and can certainly not be implemented by SD’s sunset date.

Conclusion and required steps to allow use of molybdenum coatings as an alternative to sodium dichromate

Overall, while this alternative promises complete removal of Cr(VI) from the system, without Cr(VI) in the electrolyte, additional buffer must be used. The phosphate buffer would have a detrimental effect on the stability and durability of the anodes and could lead to increased oxygen generation; it is not clear whether additional controls on oxygen would be required. A relevant patent has claimed a reduction in cell voltage and a concomitant reduction in energy consumption. However, this has not been proven at the industrial scale, especially during continuous operation of the electrolysis cells. Overall, this yet unproven alternative is not considered technically feasible.

Due to the lack of commercial scale applications known to the applicant, significant uncertainties exist regarding the commercialisation of the technology and whether or not it would work in practice. In particular, the cathode lifetime must be long enough to consider the technology technically feasible, but no data on the cathode lifetime has been found. Although this technology is promising, it can be expected that considerable R&D would still be required to demonstrate that this technology is technically feasible for commercial production of sodium chlorate. The typical steps in undertaking the required R&D and implementation steps may include:

1. R&D phase in existing electrolyte (without SD) to verify robustness

2. R&D phase to optimise buffer system needed, and effects on anodes

3. R&D to scale-up to (a) long-term tests, lab pilot (b) intermediate scale, (c) commercial scale including demonstration of cathode lifetime

4. Replacement of all Cr(VI) containing electrolyte

5. Replacement of all existing electrolytic cell cathodes

6. Process optimisation

7. Preparation of new buffered electrolyte and its maintenance

16 The following conditions for a chlorate cell employing SD were used to enable a comparison to be made to a theoretical change to molybdenum-coated cathodes. A cell voltage of 3.1 V (mid-range value from BREF (IPPC, 2007)) and current efficiency of 95% gives a theoretical energy requirement of 4,930 kWh/tonne of chlorate + 300 kWh/tonne (mid-range value for other electrical equipment) = 5,230 kWh/tonne chlorate using SD. Using molybdenum-coated cathodes, the patent indicates a current efficiency of 94% and a voltage between 2.50-2.53 V. Using these data; a mid-range cell voltage of 2.515 V and 94% efficiency, an electrical consumption of 4,042 kWh/tonne can be calculated + 300 kWh/tonne = 4,342 kWh/tonne of chlorate or a 9.9% increase in electrical consumption.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 106 8. Investigation of oxygen evolution and potentially implementation of safety measures to reduce the oxygen content of hydrogen stream

9. Potentially, implementation of systems for gas treatment to ensure clean-up of hydrogen before further use.

5.4.3 Economic feasibility

This alternative has been found to be technically infeasible to implement. Therefore it cannot be considered economically feasible for the applicant.

Appendix 3 describes the implications for the applicants if the technical feasibility is ignored and the costs calculated based on the claimed performance of the alternatives. This is provided for sake of clarity.

5.4.4 Reduction of overall risk due to transition to the alternative

Overview

Due to the nature of this alternative, a direct comparison of hazards and risks to SD cannot be performed here. However, it is of note that sodium molybdate would be the basis of the coating and the new cathodes would be used alongside a sodium phosphate buffer. Due to the lack of experience with this technology at the industrial scale, it cannot be predicted whether other additives might be needed or what species may be found in the electrolyte during the use of a chlorate cells that uses molybdenum-coated cathodes. We therefore tentatively assume that no further substance would be added to the electrolyte and no releases due to corrosion or other effects might occur '''''''' '''''''' ''''''''''''''' ''''''''''''''''''' '''''#E#''''' ''''''''''''' '''''''''''''''''' '''''''''' ''''''''''''''''' ''''''''' ''''''''''''''' ''''' ''''''''' '''''''''''''''''''''. Under this assumption and in light of the findings of Appendix 2 (on sodium phosphates and sodium molybdate), it can be assumed that this alternative would have a more benign risk profile than SD.

Externalities from energy usage

There is significant uncertainty on how energy consumption might change were molybdenum- coated cathodes to be used in the continuous operation of industrial-scale chlorate plants. Some very tentative assumptions were made above on how energy might theoretically decrease in comparison to SD, but these were only used to illustrate the potential changes to the operating costs of the applicant. In light of such significant uncertainty, a detailed calculation of externalities is not provided as it, in all likelihood, would be of dubious accuracy.

Conclusion on suitability

Molybdenum-coated cathodes could reduce risks to workers during the manufacture of sodium chlorate but environmental impacts are uncertain.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 107 5.4.5 Availability

As noted above, three elements of availability can be considered:

 Availability of the alternative in quantities sufficient for the applicant’s production processes  Availability of the alternative in the quality required by the applicant’s production processes  Access to the technology that allows the implementation of the alternative as a SD replacement.

According to the patent describing the manufacture of molybdenum-based cathodes, they are made using iron(III) chloride and sodium molybdate in a buffer solution. It can safely be assumed that these materials would be available to any company (other than the applicant) that would wish to manufacture coated cathodes. The applicant would not coat the cathodes themselves, as this is not their core business. The applicant has no knowledge of any supplier of suitable cathodes.

With regard to quality, given that the technology is not proven and unavailable on the market, assumptions on quality would be based on speculation.

Most importantly, access to the technology is the key issue. The aforementioned patent application has been filed by Industrie De Nora (Krstajic, et al., 2007). The patent is yet to be granted and the technology is yet to be proven outside the laboratory. Therefore, the alternative technology cannot be considered available to the applicant, certainly not by the sunset date for SD. In theory, assuming that the Industrie De Nora17 (or other Mo-based coating) technology would develop into an alternative suitable for use on the industrial scale without reliance on Cr(VI), it would need to be licenced from the patent holder.

5.4.6 Conclusion on suitability and availability for molybdate based coatings

Molybdate-coated cathodes were investigated as an alternative technology that would replace the use of SD in the production of sodium chlorate. The coated cathodes (used in combination with a phosphate buffer) could be considered to be a suitable alternative, although a direct comparison to the hazard profile of SD cannot be made. Calculations on the environmental externalities that would accompany the implementation of this alternative technology have not been made due to the significant uncertainties over the technical characteristics of molybdate-based coatings in an industrial environment.

It was found that molybdenum-based coatings fail to meet the majority of the technical feasibility criteria and their poor pH buffering capabilities necessitate the addition of phosphate buffers at concentrations much higher than the electrolysis cell can tolerate. It is particularly the addition of phosphates that render this alternative unrealistic: their presence in the electrolysis cells is currently kept at a minimum level and if addition of several g/L were required, the stability and durability of the anodes would be seriously impacted, unless new, more durable types of anodes could be developed.

17 The Industrie De Nora patent protection will elapse in 2026 , 20 years from filing date, 29 November 2006 (Krstajic, et al., 2007). See terms of European patents here: http://www.epo.org/law-practice/legal- texts/html/epc/2013/e/ar63.html (accessed on 3 September 2014).

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 108 It is unclear whether molybdenum-based coatings would result in the generation of excessive volumes of oxygen in the hydrogen co-product. Certainly, the presence of phosphates would exacerbate the generation of oxygen to some extent. Whether this would raise safety risks and would necessitate the introduction of processes that would allow the dilution of the generated gas mixture (typically by means of nitrogen purging), it remains to be seen. The presence of metal impurities in the final product is also a concern which is not possible to allay or confirm under the current state of knowledge.

In terms of economic feasibility, the implementation of molybdenum-coated cathodes would require significant investment (one-off) costs, including the costs of developing or acquiring access to the relevant technology (when and if this materialises in the future), the disposal of the existing electrolyte and the generation of new electrolyte, the purchase and installation of new cathodes, the losses of chlorate sales and economic impacts on ancillary operations from the stoppage of the production during conversion, and, potentially, the cost introducing/expanding oxygen controls. These costs are substantial and unjustifiable, in light of the lack of technical feasibility of the alternative. Therefore, the use of molybdenum-coated cathodes cannot be considered economically feasible to the applicant.

Finally, in terms of availability, the substances needed for the generation of the coatings are available on the EU market; however, the technology that would allow their implantation under conditions that would guarantee a minimum level of technical feasibility and economic viability is not available.

Overall, molybdenum-based coatings have not been found to be a technically or economically feasible alternative to the use of SD in the applicant’s production of sodium chlorate. Even if significant further R&D would be able to overcome the technical barriers, their economic feasibility would still remain highly uncertain without first implementing this technology at the industrial scale. 5.5 Two-compartment electrolytic systems

5.5.1 Description of alternative technology and properties

Two-compartment electrolytic systems are a different technology to the existing sodium chlorate production method employing SD. As described in Section 4.2.3, there are patents describing the use of modified chlor-alkali type cells to generate sodium chlorate. This process is currently used by some of the manufacturers of sodium chlorate to generate sodium hydroxide, sodium hypochlorite, chlorine and hydrogen. It involves combining the output streams of the process in separate chemical reactors in order to produce hypochlorite and convert it into sodium chlorate. The process is preferably carried out in a separate reactor at a different pH and temperature to an ordinary chlor-alkali cell.

Figure 5-1 below shows an example process diagram for a membrane chlor-alkali type cell employed for the production of sodium chlorate. The technology is not limited only to this configuration. Potentially, it could also consist of two or more membrane cells linked in series. The pH ranges shown in the diagram are indicative but the anode compartment pH would be substantially lower than the cathode compartment.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 109 Figure 5-1: Example chlor-alkali type chlorate production process. Based on (Cook, 1975) (Millet, 1990) (Delmas & Ravier, 1993) (Hakansson, et al., 2004)

5.5.2 Technical feasibility

Assessment of technical feasibility

Table 5-14 presents the comparison of the two-cell technology to the technical feasibility criteria for the replacement of SD in the sodium chlorate production process. As this alternative is a different technology, some of the criteria are not relevant to this comparison.

Table 5-14: Comparison of two-compartment electrolytic technology and sodium dichromate according to technical feasibility criteria Result or value achieved Technical Criteria pass? Two-compartment feasibility criteria Sodium dichromate Threshold * systems Formation of protective film that is permeable to Not relevant to Sufficient Similar to SD Not relevant hydrogen and technology impermeable to hypochlorite pH buffering and pH control required; control of oxygen pH 6.0-6.5; <4.0% O2 in oxygen produced pH 6.0-6.5; <2.5% O2 () formation H2 by volume separately from hydrogen

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 110 Table 5-14: Comparison of two-compartment electrolytic technology and sodium dichromate according to technical feasibility criteria Result or value achieved Technical Criteria pass? Two-compartment feasibility criteria Sodium dichromate Threshold * systems Cathode protection Sufficient Minimum cathode Uncertain: likely to (corrosion () (confidential) lifetime be acceptable inhibition) Current efficiency ''''#A#''''%; 5,230 5,880 kWh/t and energy >'#A#'%; <5,700 kWh/t  kWh/t theoretical theoretical consumption Solubility in Not relevant to Highly soluble Sufficient Not relevant electrolyte technology Each impurity must be considered separately. Uncertain: likely to Impurities in <5ppm Cr in solid Metals are particularly be sufficient (no firm () chlorate product chlorate product detrimental to ClO2 data) generation * parentheses indicate uncertainty over the conclusion reached due to lack of data. A tick is given only if the entire criterion is met

Detailed presentation of technical characteristics of the alternative

Formation of protective film & solubility in electrolyte: these criteria are not of relevance to this technology. pH buffering and oxygen formation: ordinarily, chlor-alkali cells do not require pH buffers as they operate at a different pH range to the chlorate reaction. For the chlor-alkali process, the anode compartment is maintained at a low pH specifically to prevent formation of chlorate (IPPC, 2001), while the cathode compartment is at a high pH due to the formation of sodium hydroxide. In order to effectively produce chlorate; however, the chlorate reactor or anode compartment must be at pH 6-6.5 and thus pH adjustment is needed. Therefore, pH control is required in the modified chlor- alkali technology. This can be, at least in part, achieved by addition of sodium hydroxide and hydrochloric acid produced from the product streams. This would involve careful process optimisation to balance the pH by the use of online monitoring and feedback loops between different process stages. Alternatively, non-Cr(VI) pH buffers could be used but their presence may complicate the electrochemistry in the electrolysis cell in a similar fashion to conventional systems. While the applicant is familiar with chlor-alkali technology in general, their experience concerns the optimal production of chlorine and sodium hydroxide and the prevention of chlorate formation (normally an unwanted by-product in chlor-alkali plants). Both of these approaches – pH balance through process optimisation and the use of non-Cr(VI) buffers – would therefore demand significant R&D for the applicant in order to optimise the conditions required.

With regard to oxygen generation, this is released in a separate compartment to hydrogen, therefore, the hazard of explosive mixtures formation is eliminated.

Cathode protection: the protection of the cathodes is less of a concern with this alternative because chlor-alkali cells are resistant to corrosion due to their requirement to handle chlorine gas. They are constructed from more expensive materials (e.g. titanium) than chlorate cells. The technical criterion for cathode protection is therefore met by this alternative. Membrane chlor-alkali cells require relatively frequent maintenance due to the short (2-5 years, according to literature) lifetime of the selective membrane that divides the cell compartments, but does not introduce additional

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 111 corrosion products that have a potential effect on product quality in the same way as steel cathode corrosion in chlorate cells. This consideration would also affect the economic feasibility of the process as described in Appendix 3.

Current efficiency and energy consumption: the theoretical energy consumption of the process can be estimated using typical consumption figures for a chlor-alkali plant BREF (IPPC, 2001) and assuming the process of converting chlorine to chlorate is 100% efficient, which means the resulting estimate will be highly conservative. A chlor-alkali plant requires 1,750 kg NaCl and 2,790 kWh of electricity to produce one tonne of chlorine gas (Cl2). Ordinarily, this energy would also produce sodium hydroxide (1.128 t/t Cl2) but it is converted into sodium chlorate in this alternative process. As discussed in Section 4.2.3 on “Other technologies”, 3 moles of Cl2 are required to produce 1 mole of NaClO3 or, if converted to tonnes, 2 tonnes of Cl2 is required to produce 1 tonne of sodium chlorate. In electrical consumption alone, a modified chlor-alkali plant would require 2,790 × 2 = 5,580 kWh/t of sodium chlorate produced. In addition to this, further energy would be required to heat solutions and concentrate them for crystallisation. Using the same assumption as for the theoretical calculation of the energy requirement for auxiliary processes used for SD of 300 kWh/t chlorate gives a total energy consumption of 5,880 kWh/t sodium chlorate produced. In addition to this, it is expected that additional water would have to be removed from the caustic by evaporation, which would further increase energy consumption. A more precise estimate of the energy consumption cannot be provided without pilot plant scale trials of this technology but it is clear that this high energy consumption would render the process technically infeasible according to the technical feasibility criteria.

Impurities in the chlorate product: the applicant has no firm data on which a conclusion can be reached as regards the presence of impurities in the chlorate, but these are likely to be limited.

Conclusion and required steps to allow use of two-compartment electrolytic systems as an alternative to sodium dichromate

The chlor-alkali technology is widely known in the industry. This technology is optimised for the production of chlorine and sodium (or potassium) hydroxide and not for the production of sodium chlorate. According to information held by Kemira, the use of two-compartment electrolysis cells is largely theoretical. However, Kemira is aware of pilot plant in the USA (of unknown size) which in the past attempted to use this technology in small scale to produce sodium chlorate. Kemira does not have the exact details on the project but understands that the pilot plant failed and a second one was never built as the project was dropped.

If this technology were to be adapted for the production of sodium chlorate, it can safely be assumed that further R&D would be required. As identified above, the energy consumption of the process must be improved for this alternative to become technically feasible. This would involve at a minimum:

1. Selection of the most appropriate ion-selective membrane for compatibility with chlorate  Identification of appropriate membrane suppliers

2. Optimisation of process conditions for any electrolysis cells and chemical reactors:  Temperature, concentration, pH at each stage  Identity and concentration of buffers (if found necessary or beneficial)  Flow rate (or residence times) for solutions at each stage

3. Evaluation in the lab before scaling-up to the pilot scale.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 112 As with all R&D efforts, the outcome of the research is not certain to result in improved technical feasibility.

Generally, the technology cannot be considered a technically realistic alternative for large-scale production of sodium chlorate and the time that would be required for its development into a credible alternative for sodium chlorate production would be in the range of decades. Kemira estimates that the implementation of a new chlor-alkali facility adapted to the production of sodium chlorate would take at least 7-10 years, after R&D begins to show promising results. Kemira also estimate that if a chlor-alkali site is already on the same site producing sodium hydroxide and chlorine, it would possibly take 5 years to integrate this plant into a separate chemical chlorate production plant. Of the three sodium chlorate plants that are operated by Kemira with a combined nameplate capacity of ''#B#'' kt/y, only one is located in the vicinity of an existing chlor-alkali plant.

5.5.3 Economic feasibility

This alternative has been found to be technically infeasible to implement. Therefore it cannot be considered economically feasible for the applicant.

Appendix 3 describes the implications for the applicants if the technical feasibility is ignored and the costs calculated based on the claimed performance of the alternatives. This is provided for sake of clarity.

5.5.4 Reduction of overall risk due to transition to the alternative

Overview

The comparison of hazards and risks between two different technologies is not as straightforward as in the case of the other alternatives assessed above. The two-compartment system removes the need for SD without introducing any new substances and without generating significant operating hazards. It would appear that the use of the technology could be beneficial in terms of eliminating exposure to and risks from SD.

The following analysis estimates and monetises the reduction in environmental damage costs impacts arising from the increase in energy consumption that would arise from the replacement of the SD-based technology with the alternative.

Externalities from energy usage

The use of two-compartment cell technology is expected to increase the energy consumption of the process by considerable amount due to a higher voltage. As described in Section 5.5.2, an additional 5,880 – 5,230 = 650 kWh/t chlorate produced of electricity is required. Considering the applicant’s annual production of ''''''#B#'''''' tonnes, this equates to an additional '''''''''#G# ''''''' kWh per year. Using greenhouse gas emission factors available from UK Department for Environment, Food and

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 113 Rural Affairs18, it can be calculated that the generation of the equivalent amount of electricity would 19 result in the release of ''''''#G#'''''''' tonnes of CO2e per year .

Monetisation of greenhouse gas emissions is based on the methodology developed by the UK government for carbon valuation in public policy appraisal20. The shadow price of carbon is closer to what would be the full social cost of carbon emissions in terms of the damages caused by carbon emissions, but also takes into account estimates of marginal abatement costs, etc. Thus, it also takes into account policy commitments and technological issues. The value used in this assessment is £31/tonne CO2 for the year 2017 (year of the Sunset Date), as shown in the relevant UK Government document21. The present day exchange rate (£1 = €1.25) was used to convert the value in £ to € (€38.8/t).

Therefore, the externalities of the increased energy consumption and concomitant CO2 emissions would be ''''''''''''' ''' ''''#G#'''' ''' ''''' ''''''''' million per year.

Conclusion on suitability

Two-compartment cell technology would eliminate the use of SD without introducing chemical substances of notable concern, therefore, the technology may be considered to be a suitable alternative for SD in the applied for use. However, its use would require additional electricity thus would result in increased CO2 emissions to the tune of ''''''#G#'''''' t/y.

5.5.5 Availability

In general, chlor-alkali technology is available on the open market, but technology specifically adapted to chlorate production is not. It would require significant R&D before it can become implementable; a pilot plant would be required to trial the use of two-compartment cells and optimise the conditions for sodium chlorate rather than chlorine production. If R&D were to be carried out successfully, the necessary finance would need to be secured to allow the commissioning of new plants based on two-compartment cell technology. These steps are impossible to undertake before the Sunset Date therefore the technology cannot be considered available to Kemira. Kemira estimates that it would take many years before the two-cell technology could become a technically feasible, realistic alternative.

In addition, the availability of membranes for a chlorate electrolyte is also crucial for this technology. In existing chlor-alkali plants, the technology is limited to chlorate concentrations of 15 g/L due to membrane quality. In the proposed technology, the electrolyte would contain up to 500 g chlorate/L.

18 Available at: http://www.ukconversionfactorscarbonsmart.co.uk/, accessed 29 September 2014.

19 The DEFRA 2013 overseas electricity generation factor of 0.22948 kg CO2e/kWh of electricity for Finland was used. Using this factor, the generation of XXX#G#XX kWh of electricity would generate an additional emission of X#G#X tonnes of CO2e per year.

20 Available at https://www.gov.uk/government/publications/updated-short-term-traded-carbon-values- used-for-uk-policy-appraisal-2014 (accessed on 13 December 2014).

21 Shadow value of carbon, available at https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/243825/background.pdf.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 114 With particular regard to securing investment funds, Kemira notes that no significant growth in the European sodium chlorate business is expected, while there may be growth in South America and, to a lesser extent, East Asia (China, Indonesia). This means there is little commercial interest in investment in new technology in Europe. This clearly impacts upon the realism and availability of the two-compartment technology.

5.5.6 Conclusion on suitability and availability for two-compartment electrolytic systems

The use of this alternative would most likely result in a reduction of risk to human health. However, it would result in increased electricity consumption, by 12.4%, and this would result in increased greenhouse gas emissions and associated environmental damage costs.

The two-compartment cell technology is not currently available in a form that can be implemented by the applicant and its technical feasibility is poor. From a practical perspective, demolition of existing chlorate plants and erection of new production plants would be accompanied by an indicative cost of €250 million. In addition, the increase in energy costs would dramatically reduce the profitability of Kemira’s operations.

Overall, this is not a feasible alternative for Kemira.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 115 Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 116 6 Overall conclusions on suitability and availability of possible alternatives

6.1 Technical feasibility of shortlisted alternatives

The production of sodium chlorate has been carried out by industry since 1886 (Tilak & Chen, 1999) and has seen continual improvements over its long history of use but no realistic alternative to the use of SD has been found despite significant R&D efforts (see Section 4.2). According to the research undertaken, no technology or substance other than SD is used anywhere in the world as a process aid in the production of sodium chlorate. Given the inability to identify a suitable alternative or technology despite extensive research, the trend among sodium chlorate manufacturers such as Kemira has been to maximise efficiency and therefore reduce the volume of Cr(VI) used, to minimise the release of Cr(VI) from the process and work towards a predominantly closed loop system to minimise the release of Cr(VI) to the environment.

Four potential alternatives have been considered in detail in this AoA:

 Alternative substance: Chromium (III) compounds (CrCl3)  Alternative substance: Sodium molybdate  Alternative technology: Molybdenum-based cathode coatings, and  Alternative technology: Two-compartment electrolytic systems.

A summary of the assessment of technical feasibility of the shortlisted alternatives is presented in Table 6-1. More specifically:

 Cr(III) compounds: Cr(III) compounds have the potential to show equivalent performance to SD, but the applicant does not have access to the particulars of the relevant technology

 Sodium molybdate: sodium molybdate has been studied by industry and academia but results have been poor and further development is required. The addition of the molybdate salt has shown issues with poor energy efficiency and pH buffering, the latter requiring the addition of phosphate buffers. The addition of such buffers, at considerably elevated concentrations, would cause major problems to the stability and durability of the anodes and would contribute to an increase in the generation of oxygen at plant scale. The evolution of increased concentrations of oxygen in hydrogen (above the limit of explosion) raises serious process safety concerns. This technology has not been proven at the industrial scale, where continuous operation puts significant strain on the electrodes, and the very presence of high concentrations of phosphates makes this alternative technically unrealistic

 Molybdenum-based coatings: claims have been made in relevant patent applications that this technology could lead to a reduction of cell voltage and, consequently, of energy consumption. This has not been proven at the industrial scale, as the lab tests described in the literature only lasted for a few hours. On the other hand, the new cathodes would also need the addition of high concentrations of phosphates, which would have a very detrimental effect on the anodes. As mentioned above for sodium molybdate, this technology has not been proven at the industrial scale, where continuous operation puts significant strain on the electrodes and the durability of the electrodes in the cell is a parameter on which little specific information is available

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 117 Table 6-1: Summary of technical feasibility of shortlisted alternatives for SD (NB. grey cells show problematic areas, parentheses show areas of uncertainty) Threshold based on SD Molybdenum-based Technical feasibility criteria Chromium(III) chloride Sodium molybdate Two-compartment systems performance coatings Formation of protective film that is permeable to hydrogen Similar to SD ()  () Not relevant and impermeable to hypochlorite   pH buffering and control of pH 6.0-6.5; <4.0% O in H Poor buffering, phosphates Poor buffering, phosphates () 2 2 () oxygen formation by volume affect anodes affect anodes pH control required Oxygen evolution Oxygen evolution (?) Cathode protection (corrosion Minimum cathode lifetime 8 ()??() inhibition) years  ()  Current efficiency and energy >95%; 5,230 kWh/t * >'#A#'%; <5,700 kWh/t 86%; 5,746 kWh/t 94%; 4,342 kWh/t 5,880 kWh/t consumption theoretical theoretical (theoretical) theoretical Solubility in electrolyte Sufficient ()  Not relevant Not relevant Each impurity must be  () considered separately. Presence of metal impurities Presence of metal impurities Impurities in chlorate product Metals are particularly () () would act as a ClO process would act as a ClO process detrimental to ClO 2 2 2 ‘poison’ ‘poison’ generation

Uncertain; patent Not used, globally. Research Not used, globally. Not used, globally for Current state of knowledge of technical parameters application filed by a past and ongoing; much Research past and ongoing; chlorate production. competitor R&D still needed much R&D still needed Significant R&D required Expected time for achieving technical feasibility for Uncertain; patent licensing Impossible to estimate; many years would be needed for R&D, pilot scale and commercialisation at industrial scale issue pending commercialisation, if R&D results are positive  Potentially technically feasible, but currently  Poor energy efficiency  Poor pH buffering  Poor energy efficiency uncertain  Phosphate effects on  Phosphate effects on  Requires complete Conclusion and technical shortcomings  Requires access to a 3rd anode anode plant rebuild party (competitor)  Explosion hazards (O )  New cathodes needed 2  Not a feasible solution patent  Not a feasible solution  Not a feasible solution

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 118  Two-compartment electrolytic systems: such systems have been used industrially for the chlor- alkali process since the late 1800’s (IPPC, 2001). As a result of their long history, this technology is very well understood; the process has many similarities to the production of sodium chlorate and it is operated by the applicant (and other companies) for the production of chlorine, hydrogen and caustic soda, but, here, a variation of the known technology would be required. the available information would suggest that this technology would result in a more expensive manufacturing process due to higher electricity consumption, more complex equipment and higher maintenance requirements. Its requirement for a complete rebuild of the sodium chlorate plants makes this a very unrealistic solution for the elimination of SD.

In conclusion, there is no certainty that any of the alternatives could demonstrate technical feasibility. 6.2 Economic feasibility of shortlisted alternatives

The only alternative that has been found to have any technical feasibility is chromium(III) chloride. This alternative would also incur only very minor changes in operating costs and is judged to be economically feasible provided that no barriers are imposed by intellectual property rights to the technology. Due to a lack of technical feasibility, the remaining alternatives cannot have any economic feasibility. Even if the technical feasibility is ignored, their use would result in plant downtime, increased operating costs and very high implementation costs. These are discussed in more detail in Appendix 3 and are summarised briefly below:

 Chromium (III) compounds: Chromium (III) compounds could be a solution that is economically more feasible than the other alternatives, as it might require smaller changes to the applicant’s plant and smaller increases to operating costs. However, the conversion costs and in particular the cost of access to the rights to use the relevant technology that is subject to a patent application are uncertain

 Sodium molybdate: sodium molybdate would be accompanied by notable investment costs, namely the disposal and replacement of the existing electrolyte, the improvement of oxygen controls (to reduce the risk of explosion) and downtime, which would affect not only the chlorate plant but also ancillary operations of the applicant. In terms of on-going costs, sodium molybdate would result in considerably increased energy consumption, increased maintenance and materials costs due to the adverse effect of phosphates on the stability and durability of the anodes and significant operating difficulties for the applicant’s ancillary operations that depend on high quality hydrogen gas. The economic feasibility of this alternative is very poor

 Molybdenum-based coatings: as with sodium molybdate, the introduction of these coatings would be accompanied by notable investment costs, namely the disposal and replacement of the existing electrolyte, the purchase and installation of new cathodes and downtime of several months, which will affect not only the chlorate plants but also ancillary operations of the applicant. In terms of on-going costs, molybdenum-coated cathodes would result in uncertain changes to energy consumption, possibly a reduction, according to a relevant patent application, increased maintenance and materials costs due to the adverse effect of phosphates on the stability and durability of the anodes and unclear impacts on ancillary operations (as it is not

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 119 clear what oxygen controls would be required). The economic feasibility of the alternative is very poor, particularly in light of the significant investment costs

 Two-compartment electrolytic systems: for this alternative, the investment costs are far greater and, realistically, prohibitive, than the previously described alternatives, as demolition of the existing chlorate plants and erection of new plants would be required at a cost of several millions of Euros. Even if such investment were feasible, the new plants would have increased maintenance requirements (the periodic replacement of membranes and higher energy consumption are the most critical components of chlorate plant operating costs). Two- compartment solutions are the most economically infeasible solution and cannot be considered as a realistic proposition.

In general, alternatives other than Cr(III) compounds have not come even close to being proven at the industrial, commercial scale; therefore, issues of economic feasibility are purely of theoretical nature, as these alternatives cannot possibly be implemented by the applicant in the foreseeable future and certainly not before the sunset date for SD. Two important points need to be made: (a) investment costs particularly for alternatives other than Cr(III) compounds would be very high, and (b) electricity (primarily for electrolysis and for ancillary tasks) accounts for – by far – the largest proportion of the production cost of the applicant. Therefore, profitability crucially depends on electricity prices and costs. Recent analysis on the projected changes in the electricity market between 2010 and 2020 and beyond indicates that “the developments in the EU28 power sector have significant impacts on energy costs and electricity prices, in particular in the short term. Power generation costs are expected to significantly increase by 2020 relative to 2010, mainly as a consequence of higher investments due to the need for significant capital replacement and higher fuel costs (because of the large increase in international fossil fuel prices). Grid costs also increase to recover high investment costs in grid reinforcements and interconnectors. Smaller components of the cost increase are national taxes and ETS allowance expenditures (…) As a result, average electricity price in the period 2010-20 increases by 31% (is estimated)” (EC, 2013). Against this backdrop, the switch to an unproven technology that could increase electricity consumption is not a viable option for the applicant, as they cannot guarantee the profitability and long-term viability of the chlorate (and certain ancillary) operations. 6.3 Reduction of risks from the use of shortlisted alternatives

There is a mixed picture with regard to the capacity of the shortlisted alternatives to reduce risks from the use of SD in the applied for use. Two-compartment systems do not use any replacement additives and do not appear to introduce notable hazards, therefore they could be considered capable of eliminating the risks from SD, and as such, suitable alternatives for SD.

For molybdenum-based solutions, Appendix 2 has demonstrated that the use of sodium molybdate and sodium phosphate buffers results in a reduction of risks, as shown by the lower RCR values estimated. Therefore, the two molybdenum-based alternatives could be considered suitable alternatives for SD. However, past research has shown that some of the technical shortcomings of these alternatives can be addressed by the addition of SD into the electrolyte. Under such a condition, the two shortlisted alternatives would evidently not be considered suitable alternatives.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 120 Conversely, Cr(III) substances may not be considered suitable alternatives for SD under the existing state of knowledge. As discussed in Section 5.2.4, the CSR describes the exposure for each type of worker who may have exposure to sodium dichromate. The six Tasks for workers, which may result in some exposure to SD, see Table 5-7. The use of CrCl3 (or other Cr(III) substance) would eliminate exposure under Task 1 (Feeding liquid SD solution into the process), however, based on the worker shift patterns assumed in the CSR (see Table 5-8), no worker would avoid exposure to SD, as all workers who may be involved in Task 1 are assumed to be involved in other tasks during which exposure to SD (via the electrolyte) will remain. The calculations made in Section 5.2.4 show that for inhalation exposure, which is the critical element of overall worker exposure, the use of a Cr(III) compound which would be oxidised into SD in the electrolyte, would only eliminate a very small percentage (20%) of aggregate exposure for day workers only. All other employees (unit workers and central laboratory workers) would not benefit from reduced exposure to Cr(VI). Therefore, Cr(III) compounds cannot be considered suitable replacements for SD even if they would result in a very small reduction in worker exposure to Cr(VI).

On the other hand, the use of some of the alternatives would result in increased use of energy and this would in turn result in increased indirect greenhouse gas emissions. These can be summarised as follows:

 '''''''''''''' ''''''''#G#''''''''' '''''''''''''''''' ''''''''' ''''''''''''''''''' ''''' ''''' '''''''''''''' '''''' '''''''''''''''''''''''''''''''''''''''''''''''''''' ''''''''''''''''' '''' ''''' '''''''' ''''''''''''''''  '''''''''''''''''''''''''''''''''''''' ''''''''''''''''' '''''' ''''''''''''''''''' ''''''' ''''' '''''''''''''''''''''''''' '''''''' ''''''''''''''''' '''' ''''''''''''' ''''''''''''''''''''''''  '''''''''''''''''''''''''''''''' ''''''''''''''''''''' ''''''''''''''' '''''''''''''''''' '''''''' '''''''''''''''''' '''' '''''' '''''''''''' ''''''' ''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''' '''' ''''' ''''''''' ''''''''''''''''''' 6.4 Availability of shortlisted alternatives

Table 6-2 summarises the previously presented discussion on the availability of the shortlisted alternatives. With the exception of Cr(III) compounds for which a competitor has filed a patent application, the other technologies are not available at the industrial/commercial scale.

Table 6-2: Summary of availability of shortlisted alternatives for SD (NB. grey cells show problematic areas) Availability Chromium(III) Molybdenum- Two-compartment Sodium molybdate criterion chloride based coatings systems  ()  Small quantities Required reagents Small quantities Quantity required available on the required, sodium Not relevant availability (NB. CrCl not market but coated 3 molybdate is REACH REACH registered cathodes not yet registered yet) available   No issues identified Technology  with the quality of specifically adapted  Technology not Quality availability the substance but to chlorate No issues identified available for use at technology not production not the industrial scale available for use at available for use at the industrial scale the industrial scale

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 121 Table 6-2: Summary of availability of shortlisted alternatives for SD (NB. grey cells show problematic areas) Availability Chromium(III) Molybdenum- Two-compartment Sodium molybdate criterion chloride based coatings systems

 Relevant patent application filed by a 3rd party and a license will be  required once 3rd party patents   patent is granted; have been applied Technology A 3rd party has filed commercial and for but the required specifically adopted Access to a relevant patent business terms of technology that to chlorate technology rights application. Patent license are would render this production not protection elapses uncertain. Unlikely alternative feasible, available for use at in 2026 to be available by is not currently the industrial scale sunset date. available Applicant has experience of the recycling of Cr(III) into the chlorate process Is the alternative available to the No No No No applicant Note: Parentheses indicate a degree of uncertainty

6.5 Overall conclusion

The overall outcome of this analysis is shown in Table 6-3.

Table 6-3: Overall conclusions on suitability and availability of shortlisted alternatives for Kemira Technical Economic Alternative Reduction in risk Availability Feasibility Feasibility Chromium(III) HH:  (-) ?  chloride ENV: - HH:  Sodium molybdate    ENV:  Molybdenum-based HH:     coatings ENV: ? Two-compartment HH:     electrolytic systems ENV:  : better than SD; : worse than SD; - : no change compared to SD Parentheses indicate a degree of uncertainty

None of the shortlisted alternatives are feasible alternatives for SD that would eliminate the exposure of workers to the Cr(VI) species responsible for SD’s SVHC status, and this conclusion supports the applicant’s request for the Authorisation of the continued use of SD in the manufacture of sodium chlorate, as is standard practice in the chlorate industry across the world.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 122 Kemira believes that the practical implementation at the industrial scale of the above or more novel solutions may lie many years into the future. A long review period for the Authorisation would not only allow time to attempt to overcome the limitations in the currently known technologies, but also to explore potentially better long-term solutions.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 123 Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 124 7 Annex – Justifications for confidentiality claims

This Annex is available in the complete version of this document.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 125 Table 7-1: Justifications for confidentiality claims

Reference type Commercial Interest Potential Harm Limitation to Validity of Claim

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 126 8 Appendix 1 – Information sources

Ahlberg Tidblad, A. & Lindberg, G., 1991. Surface analysis with ESCA and GD-OES of the film formed by cathodic reduction of chromate. Electrochimica acta, 36(10), pp. 1605-1610.

Alford, E. A. & Warren, I. H., 1994. European patent, Patent No. EP 0435434 B1.

Andolfatto, F. & Delmas, F., 2002. Specific cathode, used for preparing an alkaline metal chlorate and method for making same. US, Patent No. US6352625 B1.

BASF, 2014. DeOxo. [Online] Available at: http://www.basf.com/group/corporate/en/brand/DEOXO [Accessed 23 June 2014].

Boily, S., Shize, J., Schulz, R. & van Neste, A., 1997. ALLOYS OF Ti, Ru, Fe AND O AND USE THEREOF FOR THE MANUFACTURE OF CATHODES FOR THE ELECTROCHEMICAL SYNTHESIS OF SODIUM CHLORATE. International, Patent No. WO 1997004146 A1.

Bommaraju, T. V., Dexter, T. H. & Charles, G., 1981. Film-coated cathodes for halate cells. US, Patent No. 4295951 A.

Brasher, D. M. & Mercer, A. D., 1965. Radiotracer Studies of the Passivity of Metals in Inhibitor Solutions. Transactions of the Faraday Society, Volume 61, pp. 803-811.

Brown, C. W., Carlson, R. C. & Hardee, K. L., 2010. Cathode member and bipolar plate for hypochlorite cells. International application, Patent No. WO 2010/037706 A1.

Chlistunoff, J., 2004. Final Technical Report - Advanced Chlor-Alkali Technology, Los Alamos: Los Alamos National Laboratory.

Cook, E. H., 1975. ELECTROLYTIC MANUFACTURE OF CHLORATES, USING A PLURALITY OF ELECTROLYTIC CELLS. US, Patent No. 3,897,320.

Cornell, A., 2002. Electrode Reactions In the Chlorate Process, Doctoral Thesis, Stockholm: Royal Institute of Technology.

Cornell, A. & Simonsson, D., 1993. Ruthenium Dioxide as Cathode Material for hydrogen Evolution in Hydroxide and Chlorate Solutions.. Journal of the Electrochemical Society, 140(11), pp. 3124-3129.

CRC, 2003. Handbook of Chemistry and Physics. 84th Edition ed. Boca Raton, Florida: CRC Press LLC.

Delmas, F. & Ravier, D., 1993. Process for the production of alkali metal chlorate and apparatus therefor. France, Patent No. FR2691479 (B1).

Dobosz, L., 1987. Production of hexavalent chromium for use in chlorate cells. Europe, Patent No. EP 0266128 A2.

EC, 2013. EU Energy, Transport and GHG Emissions Trends to 2050. [Online] Available at: http://ec.europa.eu/energy/observatory/trends_2030/doc/trends_to_2050_update_2013.pdf [Accessed 23 September 2014].

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 127 Gebert, A., Lacroix, M., Savadogo, O. & Schulz, R., 2000. Cathodes for chlorate electrolysis with nanocrystalline Ti-Ru-Fe-O catalyst. Journal of Applied Electrochemistry, Volume 30, pp. 1061-1067.

Gustafsson, J., 2012. In-situ activated hydrogen evolution from pH-neutral electrolytes, Doctoral Thesis, Applied Electrochemistry, School of Chemical Science and Engineering, Kungliga Tekniska Högskolan. [Online] Available at: http://www.diva-portal.org/smash/get/diva2:527964/FULLTEXT01.pdf [Accessed 30 October 2013].

Gustafsson, J. et al., 2012b. In-situ activated hydrogen evolution by molybdate addition to neutral and alkaline electrolytes. J. . Electrochem. Sci. Eng., 2(3), pp. 105-120.

Gustafsson, J. et al., 2012. On the suppression of cathodic hypochlorite reduction by electrolyte additions of molybdate and chromate ions. J. Electrochem. Sci. Eng., Volume 2, pp. 185-198.

Gustafsson, J., Nylen, L. & Cornell, A., 2010. Rare earth metal salts as potential alternatives to Cr(VI) in the chlorate process.. Journal of Applied Electrochemistry, 40(8), pp. 1529-1536.

Gustavsson, J., 2012. In-situ activated hydrogen evolution from pH-neutral electrolytes, Stockholm: KTH Royal Institute of Technology.

Hakansson, B., Fontes, E. & Herlitz, F., 2004. Process for Producing Alkali Metal Chlorate. International application, Patent No. WO 2004 005583.

Hedenstedt, K. & Edvinsson-Albers, R., 2012. International Publication, Patent No. WO 2012/084765 A1.

Hedenstedt, K. & Edvinsson-Albers, R., 2012. International Publication, Patent No. WO 2012/084765 A1.

Hedenstedt, K. & Edvinsson-Albers, R., 2012. International Publication, Patent No. WO 2012/084765 A1.

Herlitz, F., 2001. Inhibiting effect of oxidized zirconium on parasitic cathodic reactions in the sodium chlorate process Part I: Hypochlorite reduction. Journal of Applied Electrochemistry, 31(3), pp. 307- 311.

Hummelgard, C., 2012. Nanoscaled Structures of Chlorate Producing Electrodes - Thesis, Sundsvall: Mid Sweden University.

IPCC, 2007. Climate Change 2007: Working Group I: The Physical Science Basis. [Online] Available at: http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-10-3-6.html [Accessed 24 November 2014].

IPPC, 2001. Reference Document on Best Available Techniques in the chlor-alkali manufacturing industry, s.l.: European Commission.

IPPC, 2007. Large Volume Inorganic Chemicals – Solids and Others Industry, s.l.: European Commission.

Kack, C. & Lundberg, D., 2010. Risk assessment of chlorine dioxide storage facilities. [Online] Available at: http://www.ips.se/files/pages/27/basta-exjobb-2010-5323.pdf [Accessed 2 December 2014].

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 128 Krstajic, N., Jovic, V. & Antozzi, A. L., 2010. International application, Patent No. WO 2010/06395 A2.

Krstajic, N., Jovic, V. & Martelli, G. N., 2007. System for the electrolytic production of sodium chlorate. International application, Patent No. WO 2007/063081 A2.

Krstajić, N., Spasojević, M. & Jakšić, M., 1984. Electrocatalytic optimization of faradaic yields in the chlorate cell process. Surface Technology, 21(1), pp. 19-26.

Kus, R. A., 2000. Effects of Electrolyte Impurities in Chlorate Cells. Cleveland, Ohio, s.n.

Lewis, R. J., 2000. Sax'sdangerous properties of industrial materials. New York: Wiley.

Li, M., Twardowski, Z., Mok, F. & Tam, N., 2007. Sodium molybdate - a possible alternate additive for sodium dichromate in the electrolytic production of sodium chlorate. Journal of Applied Electrochemistry, 37(4), pp. 499-504.

Lindbergh, G. & Simonsson, D., 1991. Effect of chromate addition on cathodic reduction of hypochlorite in hydroxide and chlorate solutions. Journal of the Electrochemical Society, 137(10), pp. 3094-3099.

Lindbergh, G. & Simonsson, D., 1991. Inhibition of cathode reactions in sodium hydroxide solution containing chromate. Electrochimica acta, 36(13), pp. 1985-1994.

Mendiratta, S. K. & Duncan, L. B., 2003. Chloric Acid and Chlorates. In: Kirk-Othmer Encyclopedia of Chemical Technology. s.l.:John Wiley & Sons, pp. 103-120.

Millet, J.-C., 1990. production of alkali metal chlorate or perchlorate. France, Patent No. 90/9801.

Munn, S. J. et al., 2005. European Union Risk Assessment Report: chromium trioxide, sodium chromate, sodium dichromate, ammonium dichromate, potassium dichromate. 3rd Priority List, Volume 53, Luxembourg: European Comission.

Nylén, L., 2006. Critical potential and oxygen evolution of the chlorate anode (Doctoral dissertation, KTH), s.l.: s.n.

Nylén, L., 2008. Influence of the electrolyte on the electrode reactions in the chlorate process, Stockholm: Doctoral thesis - KTH Chemical Science and Engineering.

Nylén, L., Behm, M., Cornell, A. & Lindberg, G., 2007. Investigation of the oxygen evolving electrode in pH-neutral electrolytes: modelling and experiments of the RDE-cell. Electrochimica Acta, 52(13), pp. 4513-4514.

Nylén, l. & Cornell, A., 2006. Critical anode potential in the chlorate process. Journal of the Electrochemical Society, 153(1), pp. D14-D20.

Nylén, L., Gustavsson, J. & Cornell, A., 2008. Cathodic reactions on an iron RDE in the presence of Y (III). Journal of the Electrochemical Society, 155(10), pp. 136-142.

Ragauskas, A., undated. Chemistry of Chlorine Dioxide Pulp Bleaching. [Online] Available at: http://ipst.gatech.edu/faculty/ragauskas_art/technical_reviews/General%20ClO2%20Generation%2 0of%20ClO2.pdf [Accessed 31 December 2014].

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 129 Ramsay, J. D., Xia, L., Kendig, M. W. & McCreery, R. L., 2001. Raman spectroscopic analysis of the speciation of dilute chromate solutions. Corrosion Science, 43(8), p. 1557–1572.

Rosvall, M., Edvinsson-Albers, R. & Hedenstedt, K., 2009. Electrode. International, Patent No. WO 2009/063031 A2.

Rosvall, M. et al., 2010. Activation of cathode. International, Patent No. 130546 AA.

Schulz, E. & Savoie, S., 2009. A new family of high performance nanostructured catalysts for the electrosynthesis of sodium chlorate. Journal of Alloys and Compounds, Volume 483, pp. 510-513.

Schulz, R., Bonneau, M.-E., Roue, L. & Guay, D., 2006. TI5 RU AND AL-BASED ALLOYS AND USE THEREOF FOR SODIUM CHLORATE SYNTHESIS. International, Patent No. WO 2006/072169 A1.

Schulz, R. & Savoie, S., 2010b. NANOCRYSTALLINE ALLOYS OF THE FE3AL(RU) TYPE AND USE THEREOF OPTIONALLY IN NANOCRYSTALLINE FORM FOR MAKING ELECTRODES FOR SODIUM CHLORATE SYNTHESIS. US, Patent No. 2010/0159152 A1.

Schulz, R. & Savoie, S., 2010. Properties of iron aluminide doped with a catalytic element for the electrosynthesis of sodium chlorate. Journal of Alloys and Compounds, 504(1), pp. 295-298.

Schulz, R. & Savoie, S., 2013. Alloys of the type Fe3AlTa(Ru) and use thereof as electrode material for the synthesis of sodium chlorate or as corrosion resistant coatings. International, Patent No. WO 2013173916 A1.

Schulz, R., Van Neste, A., Boily, S. & Jin, S., 1997. ALLOYS OF Ti, Ru, Fe AND O AND USE THEREOF FOR THE MANUFACTURE OF CATHODES FOR THE ELECTROCHEMICAL SYNTHESIS OF SODIUM CHLORATE. International application, Patent No. WO 97/004146.

Speight, J. G., 2002. Chemical and process design handbook. s.l.:McGraw-Hill.

Tilak, B. & Chen, C. P., 1999. Chlor-Alkali and Chlorate Technology: R. B. MacMullin Memorial Symposium. In: H. S. Burney, N. Furuya, F. Hine & K. Ota, eds. Electrolytic Sodium Chlorate Technology: Current Status. Pennington(New Jersey): The Electrochemical Society, Inc., pp. 8-40.

Van Neste, A. et al., 1996. Low Overpotential Nanocrystalline Ti-Fe-Ru-O cathodes for the production of sodium chlorate. Switzerland, Trans Tech Publications, pp. 795-800.

Yoshida, H., Akazawa, T. & Hane, T., 1981. Activated cathode. US, Patent No. 4,300,992.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 130 9 Appendix 2 – Comparative hazard and risk characterisation of alternatives

9.1 Background

Article 60 (5) of REACH requires the applicant to investigate whether the use of the alternative substance “would result in reduced overall risks to human health and the environment” (as compared to the Annex XIV substance).

In order to comply with this requirement in this document the hazard profiles of those substances selected to be evaluated in detail are presented and suitable reference values for a quantitative comparison (DNELs for human health assessment, PNECs for an assessment of environmental toxicity) are either identified or (if no such reliable basis could be found in the public domain) derived.

Three substances were selected for in-depth analysis:

 Chromium (III) chloride hexahydrate  Sodium molybdate (VI) dihydrate  Phosphate buffer containing sodium dihydrogen orthophosphate and disodium hydrogen phosphate to be used in combination with molybdenum coated cathodes.

Literature searches (up to May 2014) were performed for alternative substances in bibliographic databases as appropriate (after consultation of existing assessments) and assessments available from eChemPortal and other sources were screened.

As not only a comparison of hazard profiles is required but a comparison of substance properties on a risk basis, a human health and environmental exposure scenario is developed (Section 9.3). Exposure within this scenario is estimated using the Tier I tool ECETOC TRA v.3. This approach is different to that used in the CSR, as it should be applicable in a similar way for all substances assessed. For an indicative comparison of occupational exposure, task 2 (sampling) was selected, since this constitutes the task carried out most frequently (daily).

Section 9.4 presents the comparative risk characterisation and the overall conclusions on risks from using the alternative substances. 9.2 Reference values for sodium dichromate and alternative substances

9.2.1 Sodium dichromate

Classification

Sodium dichromate, CAS 10588-01-9

According to Annex VI of the CLP Regulation SD is classified as follows:

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 131 Figure 9-1: Classification of sodium dichromate

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 132 Sodium dichromate dihydrate, CAS 7789-12-0

No classification according to Annex VI of the CLP Regulation is available. Classification according to classification and labelling inventory (no joint entry, highest number of notifiers) is as follows:

Figure 9-2: Classification of sodium dichromate dihydrate

Ecotoxicity

Existing reference values

Predicted no effect concentrations as derived in the registration dossier as presented in ECHA- CHEM, the EU-RAR (ECB, 2005) and the CICAD assessment (WHO, 2013) are given in Table 9-1. The numerical values for the freshwater PNECs presented in all three sources are nearly identical; however, the underlying basis is different. Using the species sensitivity distribution approach (SSD) the EU-RAR (ECB, 2005) and CICAD assessment (WHO, 2013) derived a PNECfreshwater of 3.4 µg/L and 4 µg/L, respectively. The value presented in the CICAD document is based on the lower 95% confidence limit on the hazardous concentration for the protection of 95% of species (HC5-95%). The value presented in the EU-RAR is based on the lower 95% confidence limit on the hazardous concentration for the protection of 50% of species (HC5-50%) using an additional assessment factor of 3. The underlying basis for the PNECfreshwater presented in the registration dossier in ECHA-CHEM (ECHA, 2014) is unclear. Most probably – as can be concluded from the data presented in the registration dossier – it refers to Ceriodaphnia dubia NOEC for reproduction of 4.7 µg Cr(VI)/L. According to EU-RAR (ECB, 2005) an assessment factor of 10 should be applied resulting in a PNECfreshwater of 0.47 µg/L chromium (VI) documented, which is a factor 10 lower than the value documented in the table below. The reason for this discrepancy remains unclear.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 133 Identical PNECs were derived in all three sources for PNECSTP and PNECsoil (slight differences are due to rounding). According to EU-RAR in soil Cr(VI) would be reduced to Cr(III), and this would be expected to have been the case also in many of the soil toxicity tests.

Numerical values for PNECsediment are also identical in the registration dossier and in the EU-RAR, but the one in the registration dossier refers to dry weight and the one in the EU-RAR to wet weight. Probably there is a mistake in the registration dossier as it refers to the EU-RAR for the assessment of sediment toxicity. The EU-RAR points out that the PNECsediment is very tentative based on freshwater toxicity and equilibrium partitioning, as most of Cr(VI) will be transformed to Cr(III) under conditions found in most sediments, and Cr(III) formed would be expected to be poorly soluble and thus of reduced bioavailability.

Table 9-1: Predicted no effect concentrations for different environmental compartments – values from ECHA-CHEM compared to EU RAR (ECB, 2005) and a CICAD assessment (WHO, 2013) ECHA-CHEM EU RAR (2005) CICAD (2013) based on Cr(VI) based on Cr(VI) based on Cr(VI)

PNECfreshwater 4.7 µg/L, AF 10 (0.47 µg/L, AF 10); SSD SSD (HC5-95%): 4 µg/L (HC5-50%, AF 3): 3.4 µg/L PNECmarine-water not derived not derived 0.09 µg/L (AF 50) PNECintermittent-releases not derived not derived not derived PNECSTP 0.21 mg/L, AF 1 0.21 mg/L, AF 1 0.2 mg/L, AF 1 PNECsediment 0.15 mg/kg sed. dw (EPM) 0.15 mg/kg sed. ww (0.69 not derived mg/kg sed. dw.)

PNECsoil 35 µg/kg soil dw., AF 10 35 µg/kg soil dw., AF 10 0.04 mg/kg soil dw., AF 10

Discussion of suitability of reference values for comparative assessment

The most relevant reference value for comparison with alternative substances is the PNECfreshwater. In contrast to PNECsoil it is largely attributable solely to Cr(VI) species. It is based on a large chronic data set from a wide range of aquatic taxa, while the sediment value is based on the freshwater data and EPM only.

In regard to STP microorganism toxicity, also the PNECSTP as derived within EU-RAR (ECB, 2005) is valid (this value is also referred to by ECHA-CHEM). It is based on a review of several studies on single microbial strains as well as an activated sludge respiration inhibition test. With appropriate assessment factors, resulting PNECs were mostly of similar magnitude, and the lowest value based on a single-organism study was used to derive the value.

Conclusions: PNECs for comparative assessment

The PNECfreshwater of 3.4 µg Cr(VI)/L derived within the EU risk assessment (ECB, 2005) is the most valid value as derivation is very well documented and corresponds to the methodology outlined in REACH guidance on information requirements and chemical safety assessment, part R.10 (ECHA, 2008). This value will be used for comparative assessment of alternatives to SD.

Regarding sewage treatment plant microorganisms, the PNECSTP derived within the EU risk assessment (ECB, 2005) of 0.21 mg Cr(VI)/L is valid and will be used for comparative assessment of alternatives to SD.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 134 Human Health

Existing reference values

Sodium dichromate (CAS 10588-01-9) has been registered in the tonnage band 10,000-100,000 tons/year (ECHA, 2014). The DMELs/DNELs reported in the following table are taken form the application CSR. Values are presented for the Cr(VI) ion, which is the molecular entity that drives carcinogenicity of SD and is released when the substance solubilises and dissociates.

Table 9-2: Worker DMELs/DNELs for sodium dichromate (CAS 10588-01-9) – values from authorisation CSR Route of Systemic effects Local effects exposure Acute Long-term Acute Long-term Chromium triacetate* Inhalation High hazard (no Not derived High hazard (no DMEL 0.0025 µg/m3 * threshold derived) threshold derived) (effect) (lethality, Cat 2) (severe skin burns (lung cancer) and eye damage) Dermal No hazard identified Not derived High hazard (no Not derived threshold derived) (skin corrosion) (effect) (lethality, Cat 4) (severe skin burns and eye damage) * associated with an excess risk of 1 x 10E-5

Long-term inhalation to chromium (VI) causes lung tumours in humans and animals. There is no evidence that inhalation exposure to chromium (VI) causes tumours at other localisations. Therefore, chromium (VI) is a local acting carcinogen and for local effects after long-term inhalation exposure, a DMEL was derived on basis of epidemiological data in humans assuming a linear dose- response relationship.

No DNEL was derived for local effects after acute inhalation exposure. This exposure is characterised by a ‘High hazard’ according to the ‘Guidance on Information Requirements and Chemical Safety Assessment Part E: Risk Characterisation’ (ECHA, 2012a) and due to the classification of SD as ‘Skin corrosive Cat 1B (H314: Causes severe skin burns and eye damage). This hazard was treated in a qualitative but not a quantitative manner.

In a subchronic inhalation study with rats local effects in the lung and effects on the humoral immune response were observed (LOAEC 25 µg/m3, continuous exposure 22 h/d, 7 d/w). Although this study has some shortcomings for the purpose of comparison a calculation has been performed in the CSR to see which DNEL would result for systemic effects after long-term inhalation exposure. The resulting value was above the DMEL for local effects. As the DMEL for local effects protects from systemic effects no DNEL was derived for systemic long-term effects after inhalation exposure.

SD is classified as acute toxic Cat 2 after inhalation exposure (H330: Fatal if inhaled). Therefore a ‘High hazard’ was assigned for systemic effects after acute inhalation exposure according to the ‘Guidance on Information Requirements and Chemical Safety Assessment Part E: Risk Characterisation’ (ECHA, 2012a). This hazard was treated in a qualitative but not a quantitative manner.

No DNELS were derived with respect to local effects after dermal exposure. Due to the skin corrosive properties and its classification as skin sensitising substance (category 1) a ‘High hazard’ was

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 135 assigned for systemic effects after acute inhalation exposure according to the ‘Guidance on Information Requirements and Chemical Safety Assessment Part E: Risk Characterisation’ (ECHA, 2012a). No quantification of this hazard is possible and the risk possibly associated with this route of exposure has to be controlled by appropriate risk management measures.

SD elicits only very low acute toxicity after dermal contact. It is classified as acutely toxic (category 4) after dermal exposure (H312: Harmful in contact with skin), therefore no hazard was attributed for systemic effects after acute dermal exposure according to ‘Guidance on Information Requirements and Chemical Safety Assessment Part E: Risk Characterisation’ (ECHA, 2012a). Acute dermal effects are dominated by corrosive reactions to the skin which were treated in a qualitative manner. It can reasonably be assumed that protection from local effects will also protect from systemic effects after dermal exposure.

Systemic toxic effects may occur in the context of extensive dermal exposure, which are accompanied by local reactions. As the local effects are dominating overall toxicity, no DNEL for systemic effects after long-term dermal exposure has been derived and a qualitative assessment of the local effects after long-term dermal exposure has been performed.

Discussion of suitability of reference values for comparative assessment

The relevant endpoint for comparing effects after long-term exposure is carcinogenicity after inhalation exposure. The DMEL reported in the CSR and in Table 9-2 is the same as reported by RAC22 in its ‘Application for authorisation: establishing a reference dose response relationship for carcinogenicity of hexavalent chromium’, which has been derived by linear extrapolation to the low dose range. As RAC recognised that ‘mechanistic evidence is suggestive on non-linearity, it is acknowledged that the excess risk in the low exposure range might be an overestimate’ this value bears some uncertainty which cannot be further quantified at the moment.

Conclusions: Tentative DNELs for comparative assessment

For a comparative risk characterisation of human health after inhalation exposure the DMEL for long-term inhalation exposure, local effects (DMEL: 0.0025 µg/m3 associated with an excess risk of 1 x 10E-5) is used.

9.2.2 Chromium(III) chloride hexahydrate, CAS 10060-12-5

Classification

For chromium (III) compounds, no Harmonised Classification according to Annex VI of the CLP Regulation is available. For chromium (III) chloride hexahydrate (CAS 10060-12-5), classification according to classification and labelling inventory (highest and second highest number of notifiers) is as follows:

22 See http://echa.europa.eu/documents/10162/13579/rac_carcinogenicity_dose_response_crvi_en.pdf.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 136 Figure 9-3: Classification of chromium (III) chloride hexahydrate

Deviating from this classification for chromium chloride hexahydrate chromium trinitrate has been classified as

 Oxidising solid Cat 3 (H272: May intensify fire; oxidiser),  Skin sensitising Cat 1A (H317: May cause an allergic skin reaction)  Acute toxic Cat 4 after inhalation (H332: Harmful if inhaled)  Aquatic Chronic toxic Cat 2 (H411: Toxic to aquatic life with long lasting effects)

In the registration dossier, chromium triacetate has been classified as skin sensitising Cat 1B (H317: May cause an allergic skin reaction) in the registration dossier. All three substances are soluble Cr(III) salts and human health hazards are probably due to Cr(III).

Ecotoxicity

Existing reference values

Chromium (III) chloride is not registered under REACH. Instead, predicted no effect concentrations for the soluble chromium (III) compounds chromium triacetate (CAS: 1066-30-4) and chromium trinitrate (CAS: 13548-38-4) are available in ECHA-CHEM. Further, PNECs for soluble chromium (III) compounds in general are reported in EU-RAR (ECB, 2005) (the report is on Cr(VI), but Cr(III) was also assessed) and the CICAD assessment (WHO, 2009) on inorganic chromium (III) compounds. Studies on chromium trichloride were included in both of these assessments, as observed toxicities are obviously independent of the counter-ions. PNEC values from these four sources are summarised in Table 9-3.

Chromium trinitrate is a soluble Cr(III) compound with a comparatively large (chronic) dataset available according to ECHA-CHEM, while for chromium triacetate only acute data are reported. These acute data were largely derived in medium to hard water, while toxicity of chromium (III) most likely increases with decreasing hardness and decreasing salinity, i.e. highest toxicity is observed in soft freshwater, and lower toxicity in marine water compared to freshwater (ECB, 2005; WHO,

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 137 2009). This may explain the difference seen in the PNEC values for freshwater which are between 22.7 µg Cr(III)/L for chromium triacetate and around 5 µg Cr(III)/L for chromium trinitrate as well as chromium (III) compounds in general according to EU-RAR (ECB, 2005) or the CICAD assessment (WHO, 2009) (identical values, rounded in case of CICAD), where different chromium (III) compounds were assessed together.

As mentioned above, EU-RAR and CICAD evaluate ecotoxicity studies for (soluble) Cr(III) compounds, independently from the counter ions. Studies evaluated in EU-RAR were mainly conducted with chromium trichloride, chromium trinitrate and chromium potassium sulphate.

Table 9-3: Predicted no effect concentrations for different environmental compartments – values from ECHA-CHEM (chromium triacetate and trinitrate) compared to EU RAR (ECB, 2005) and CICAD (WHO, 2009) ECHA-CHEM, ECHA-CHEM, EU RAR (2005) CICAD (2009) chromium chromium based on Cr(III) based on Cr(III) triacetate trinitrate based on Cr(III) based on Cr(III)

PNECfreshwater 22.7 µg/L, AF 1000 4.87 µg/L, AF 10 4.7 µg/L, AF 10, for SSD (HC1-50%): 10 soft water µg/L (<100 mg/L CaCO3); 5 µg/L, AF 10, for soft water

PNECmarine-water 2.27 µg/L, AF 10000 0.97 µg/L, AF 50 not derived 2 µg/L, AF 1000 PNECintermittent-releases 227 µg/L, AF 100 4.03 µg/L, AF 100 not derived not derived PNECSTP 1.13 mg/L, AF 100 506.6 µg/L, AF 100 not derived not derived PNECsediment not derived 70.8 µg/kg sed. dw, 31 mg/kg sed. w/w not derived AF 100. (143 mg/kg sed. dw), EPM for acidic conditions (lower ads.)

PNECsoil not derived 70.8 µg/kg soil dw., 3.2 mg/kg soil dw, 3.2 mg/kg soil dw, AF 100 AF 10 AF 10

Using chromium triacetate in medium to hard water, in the available acute fish test (96 h; hardness: ca. 202 mg/L CaCO3) as well as the acute test with daphnia magna (48 h; hardness: 250 mg/L CaCO3), no effects were observed up to the limit concentration of 100 mg/L nominal (mean measured 87.8 mg/L), corresponding to a nominal Cr(III) concentration of 22.7 mg/L. No data are available for algae for this compound. While the aquatic PNEC derived for chromium trinitrate is based on a 72 days NOEC (reproduction & behaviour) of 48 µg Cr(III)/L established with freshwater fish Salmo gairdneri (hardness: 25 mg/L CaCO3), practically the same value results from the assessments performed within EU-RAR and CICAD based on a NOEC derived from a life-cycle test on Daphnia magna (47 µg/L; hardness: 52 mg/L CaCO3) using also chromium trinitrate. Both of these decisive tests were performed using soft water.

The test for STP microorganisms reported for chromium triacetate is based on read across to chromium sulphate. The activated sludge respiration inhibition test leads to an EC50 based on Cr(III) of 49 mg/L. By application of an AF of 100, a PNECSTP of 490 µg Cr(III)/L would result , pronouncedly differing from the PNECSTP of 5 mg/L available from ECHA-CHEM for chromium triacetate (corresponding to 1.13 mg Cr(III)/L). This may be due to a mistake in molecular weight calculations. The recalculated PNECSTP of 490 µg Cr(III)/L based on the chromium triacetate dossier is practically the same size like the one reported for chromium trinitrate (506.6 µg Cr(III)/L), which is based on Tetrahymena pyriformis IC50 (9 h) of 50 mg Cr(III)/L.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 138 Discussion of suitability of reference values for comparative assessment

For PNECfreshwater, reference values derived based on chronic test data using soft water are to be preferred over acute data derived using medium to hard water. Thus, PNECfreshwater values reported according to ECHA-CHEM for chromium trinitrate and according to EU-RAR (ECB, 2005) and the CICAD assessment (WHO, 2009) for Cr(III) compounds in general are all valid. PNECSTP as presented in ECHA-CHEM for chromium triacetate cannot be used due to obvious mistakes in molecular weight calculations, but the value of 490 µg Cr(III)/L derived by recalculation from key study results is valid. This value (490 µg Cr(III)/L) is practically identical to the PNECSTP reported for chromium trinitrate, in spite of being based on different key studies.

Values for sediment and soil are given as reported but will not be used for the comparative assessment.

Conclusions: PNECs for comparative assessment

The PNECfreshwater as derived within the EU risk assessment (ECB, 2005) of 4.7 µg Cr(III)/L) is used for the comparative assessment.

Regarding sewage treatment plant microorganisms: as the respiration inhibition test is most widely accepted as an indicator for combined microbial inhibition in STPs, the PNECSTP according to the recalculated PNEC-value from the chromium triacetate dossier of 490 µg Cr(III)/L will be used in the assessment of alternatives to SD.

Human toxicity

Existing reference values

Chromium(III) chloride hexahydrate is not registered under REACH. However, the closely related substances chromium triacetate (CAS: 1066-30-4) and chromium trinitrate (CAS: 13548-38-4) are registered in the tonnage band 10-100 tons/year and 100-1000 tons/year, respectively. Additional information is available from the CICAD assessment (WHO, 2009) on chromium (III), an EFSA evaluation on chromium(III) picolinate and the German MAK evaluation of chromium (III) (Hartwig, 2009).

The DNELs as reported in ECHA-CHEM for chromium triacetate (CAS: 1066-30-4) and chromium trinitrate (CAS: 13548-38-4) are outlined in Table 9-4.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 139 Table 9-4: Worker DNELs for chromium triacetate (CAS 1066-30-4) and chromium trinitrate (CAS 13548-38- 4) – values from ECHA-CHEM (ECHA, 2014) Route of Systemic effects Local effects exposure Acute Long-term Acute Long-term Chromium triacetate* Inhalation 1097 mg/m3 4.24 mg/m3 36 mg/m3 0.141 mg/m3 (effect) (248.9 mg/m3) (0.96 mg/m3) (8.2 mg/m3) (0.03 mg/m3) (repeated dose (repeated dose (repeated dose (repeated dose toxicity) toxicity) toxicity) toxicity) Dermal 40.3 mg/kg bw/d 20.2 mg/kg bw/d 8 mg/cm2 Not derived (effect) (9.1 mg/kg bw/d) (4.6 mg/kg bw/d) (1.8) (skin sensitisation) (repeated dose (repeated dose (skin toxicity) toxicity) irritation/corrosion) Chromium trinitrate* Inhalation 0.619 mg/m3 0.464 mg/m3 0.21 mg/m3 0.155 mg/m3 (0.08 mg/m3) (0.06 mg/m3) (0.026 mg/m3) (0.02 mg/m3) (effect) (repeated dose (repeated dose (repeated dose (repeated dose toxicity) toxicity) toxicity) toxicity) Dermal 0.32 mg/kg bw/d 0.32 mg/kg bw/d High hazard High hazard (0.07 mg/kg bw/d) (0.07 mg/kg bw/d) (effect) (repeated dose (repeated dose (qualitative (qualitative toxicity) toxicity) assessment) assessment) *values for Cr(III) are presented in brackets; values for Cr(III) as presented for chromium triacetate were calculated considering the molecular weight of chromium triacetate (229.13 g/mol); Cr(III) concentrations as presented for chromium trinitrate were calculated on basis of the Cr(III) content of the underlying NOAEL concentrations/doses and considering the applied assessment factors

Evaluation of long-term inhalation exposure of chromium triacetate and chromium trinitrate is based on a 90-day inhalation toxicity study in rats performed with basic chromium sulphate as surrogate for soluble Cr(III) salts (Derelanko et al., 1999). Animals were exposed to 17, 54, 164 mg/m3 basic chromium sulphate (corresponding to 3, 10, 30 mg Cr(III)/m3) for 6 hours/day on 5 days/week. Local effects (especially inflammation) were already observed in the lowest dose group. Systemic effects (decreased body weight and haematological findings) were obvious in the middle and high dose group. According to WHO (2009) a concentration of 3 mg Cr(III)/m3 can therefore be regarded as NOAEC for systemic effects and LOAEC for local effects. The results were interpreted in a similar way in the registration dossier for chromium trinitrate, but interpretation was different in the registration dossier of chromium triacetate.

The DNEL for systemic effects after long-term inhalation exposure for chromium trinitrate is based on the study of Derelanko et al. (1999) assuming a NOAEC of 17 mg/m3 soluble basic chromium sulphate (corresponding to 3 mg Cr(III)/m3 and to 23.1 mg/m3 chromium trinitrate nonahydrate). The human equivalent concentration (6 h exposure of rats to 8 h human exposure: factor 2) was given as a NAEC of 11.61 mg chromium trinitrate/m3. The DNEL was derived by application of a default assessment factor of AF 25 (2 subchronic to chronic, 2.5 interspecies and 5 intraspecies variability). The DNEL for systemic effects after acute exposure was extrapolated from the long term DNEL, but no further information was provided.

Starting from a LOAEC of 17 mg/m3 soluble basic chromium sulphate (corresponding to 3 mg Cr(III)/m3 and to 23.1 mg/m3 chromium trinitrate nonahydrate) for local effects a DNEL of 0.155 mg/m3 was derived for local effects after long-term inhalation exposure (AF 75: 3 LAEC to NAEC, 2 subchronic to chronic, 2.5 interspecies and 5 intraspecies variability). The DNEL for the acute local

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 140 effects (0.21 mg/m3) after inhalation exposure was extrapolated from the long-term DNEL, but no further information has been provided for the extrapolation.

The DNELs for long-term and acute systemic effects after dermal exposure are based on an oral subchronic (20-week) toxicity study with chromium trichloride in rats, with a NOAEL of 21.3 mg chromium trichloride/kg bw/d (corresponding to 7 mg Cr(III) /kg bw/d corresponding to 32 mg chromium trinitrate/kg bw/d). For the long-term DNEL an overall assessment factor of 100 was used (2 subchronic to chronic, 4 scaling rat, 2.5 remaining interspecies and 5 intraspecies variability). No additional factor for route to route extrapolation was applied as for both routes, oral and dermal, a very low absorption (10%) was assumed. The acute DNEL value was extrapolated from the long term DNEL value. As both values are numerically identical there seems to be an error in the documentation.

Chromium trinitrate has been classified as skin sensitising substance in the registration dossier (Cat 1A, H317: May cause an allergic skin reaction) based on the results of a guinea pig maximisation test performed with chromium trichloride. Due to this classification, no DNEL for dermal local effects after long term exposure was derived and a qualitative hazard assessment was performed for local effects. As stated in the CICAD document Cr(III) ‘acts as the ultimate haptenic determinant for chromium sensitisation in the skin; however, especially because of their lower penetration into the skin, trivalent chromium compounds are less potent sensitisers than hexavalent chromium compounds’.

The DNEL for systemic effects after long-term inhalation exposure for chromium triacetate is based on the subchronic repeated dose toxicity study in rats performed with soluble basic chromium sulphate (Derelanko et al., 1999). The highest dose applied was selected as NOAEC for systemic toxicity (NOAEC: about 210 mg chromium acetate/m3). The human equivalent concentration (6 h exposure of rats to 8 h human exposure: factor 2) is a NAEC of 106 mg/m3. The DNEL was derived by application of an overall default assessment factor of AF 25 (2 subchronic to chronic, 2.5 interspecies and 5 intraspecies variability). The DNEL for systemic effects after acute exposure is based on a repeated dose inhalation toxicity study (NAEC 13718 mg/m3; AF 12.5: 2.5 interspecies and 5 intraspecies variability). The underlying study could not be identified in the registration dossier. A DNEL of 0.141 mg/m3 has been derived for local effects after long-term inhalation exposure (AF 75: 3 LAEC to NAEC, 2 subchronic to chronic, 2.5 interspecies and 5 intraspecies variability). The underlying study is the same as used for derivation of DNEL long-term systemic which resulted in a DNEL for local effects of 21 mg chromium acetate/m3, which corresponds to a human equivalent concentration of 10.5 mg chromium acetate/m3. The DNEL for the acute local effects after inhalation exposure is based on a repeated dose study with an (adjusted) LOAEC of 1370 mg/m3 (AF 38: 3 LAEC to NAEC, 2.5 interspecies and 5 intraspecies variability). The underlying study could not be identified in the registration dossier.

The DNELs for long-term and acute systemic effects after dermal exposure are based on an oral subchronic toxicity study in rats performed with chromium picolinate monohydrate. No adverse effects were observed up to the highest dose tested (50000 ppm) (Rhodes et al., 2005). The dose was converted to basic acetate monohydrate (NOAEL of 2015 mg/kg bw/d). For the long-term DNEL an overall assessment factor of 100 was used (2 subchronic to chronic, 4 scaling rat, 2.5 remaining interspecies and 5 intraspecies variability) without any further factor for route-to-route extrapolation. The derivation of the acute value was performed in a similar manner without the time extrapolation factor. Chromium triacetate has been classified as skin sensitising substance in the registration dossier (Cat 1B, H317: May cause an allergic skin reaction) based on the results of a mouse local lymph node assay performed with basic chromium acetate. The EC3 value determined in the LLNA assay was < 5% (not further specified, because even the lowest concentration tested

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 141 (5%) resulted in SI values of > 3%. Due to this classification, no DNEL for dermal local effects after long term exposure was derived.

A DNEL of 8 mg/cm2 was derived for dermal local effects after acute exposure. This value is obviously based on human data, because only an intraspecies assessment factor of 5 was applied. However, it is not obvious from the registration dossier on which data this DNEL is based.

Discussion of suitability of reference values for comparative assessment

Values for long-term DNELs for inhalation exposure are based on a subchronic inhalation study performed with basic chromium sulphate as surrogate for soluble Cr(III) salts in rats (Derelanko et al., 1999). The values for the systemic DNEL differ by a factor of 10, which is due to the different interpretation of the study in the registration dossiers for chromium trinitrate and chromium triacetate. Effects observed in the mid and high dose group were not regarded as toxicological relevant in the context of the evaluation of chromium triacetate. But, in accordance with the evaluation of WHO (2009), it is concluded that effects on body weight and haematology should be regarded as relevant. Therefore, the NOAEC for systemic effects derived from this study is 3 mg Cr(III)/m3. Local effects in the lung were observed in all three dose groups. In accordance with the evaluation of WHO (2009) and the evaluation of the chromium trinitrate and triacetate the lowest concentration tested (3 mg Cr(III)/m3) is regarded as LOAEC for local effects.

No adequate study could be identified for the evaluation of acute systemic or local effects after inhalation exposure. The basis for the derivation of the DNELs for systemic and local effects after acute exposure of both substances is unclear.

No toxicity studies after repeated dermal exposure could be identified. According to this, the DNELs for systemic long-term and acute exposure were derived by route-to-route extrapolation from oral studies for both chromium(III) compounds. Whereas in the case of chromium acetate a subchronic study performed with chromium picolinate in rats was used the DNELs for chromium trinitrate for long-term and acute systemic effects after dermal exposure are based on an oral subchronic (20 week) toxicity study with chromium trichloride in rats with a NOAEL of 21.3 mg chromium trichloride/kg bw/d (corresponding to 7 mg Cr(III) /kg bw/d corresponding to 32 mg chromium trinitrate/kg bw/d). Rats were fed a diet supplemented with 0, 5, 25, 50, or 100 mg Cr(III)/kg as chromium chloride for a period of 20 weeks. According to WHO (WHO, 2009) this corresponds to 0.35 to 7 mg Cr(III)/kg bw/day. As no adverse effects were observed in this study a NOAEL of 7 mg Cr(III) can be deduced for Cr(III) as chromium trichloride.

Taking into account the results of the study with chromium picolinate where no toxic effects were observed up to the highest dose tested (50000 ppm corresponding to 4240 mg of chromium picolinate monohydrate/kg bw/day for rats) according to EFSA (2010) the NOAEL of Cr(III) seems to be much higher than 7 mg/kg bw/d. From the study with chromium picolinate a NOAEL of about 500 mg Cr(III)/kg bw/d resulted, which was used as basis for the evaluation of chromium picolinate by EFSA (2010).

No reliable studies on the reproductive toxicity of chromium trichloride could be identified in ECHA- CHEM. Repeated dose toxicity studies did not indicate any effects on reproductive organs or sperm parameters. In a developmental toxicity study with chromium chloride, no effects were observed at 200 mg/kg bw/day (rats, exposure from GD 6-17, only one dose). Additional investigations with chromium picolinate do not indicate a risk for reproduction by Cr(III) (EFSA, 2010; WHO, 2009). In a drinking water study male Swiss mice (9-10 per group) were exposed to chromium(III) chloride hexahydrate of 2000 or 5000 mg/l (corresponding to chromium doses of about 82 or 204 mg/kg

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 142 body weight and day) 12 weeks before mating with untreated females (Hartwig, 2009). Males of the low and high dose showed a statistically significant decrease in body weights and relative preputial gland weights, relative testis weights were significantly increased. In the high dose group fertility was significantly reduced. In addition, female mice given chromium(III) chloride with the drinking water in concentrations of 2000 and 5000 mg/L (chromium doses of about 85 and 212 mg/kg body weight and day), respectively, were mated with untreated males. Body weight of the females was not affected. Females of the high dose group had statistically significant decreased relative ovarian and uterus weights. A statistically significant reduction in the number of implants and the number of viable foetuses was observed (Hartwig, 2009). In male rats treated with chromium(III) chloride hexahydrate in concentrations of 1000 mg/L drinking water (chromium doses of about 24 mg/kg body weight and day) for 12 weeks before mating with untreated females (1:2) there was a statistically significant decrease in body weights, absolute testis weights, and the absolute and relative weights of the preputial glands and seminal vesicles. The number of pregnant dams, of implants per animal and of living offspring was comparable with the numbers in the controls (Hartwig, 2009).

Chromium (III) has been identified as skin sensitising agent according to WHO (2009) and Hartwig (2009). As reported above, chromium (III) chloride induced skin sensitisation in a guinea pig maximisation test. Therefore, Cr(III) should be classified as skin sensitising. Therefore, no quantitative and only a qualitative hazard assessment can be performed for local effects after dermal exposure.

Conclusions: Tentative DNELs for comparative assessment

Most critical for the evaluation of long-term toxicity of Cr(III) are local effects in lung seen after inhalation exposure towards soluble Cr(III). Therefore, a tentative DNEL for comparative risk assessment was derived on basis of the 90-day inhalation toxicity study with chromium sulphate in a comparative manner to the procedure described for chromium trinitrate.

DNEL long-term inhalation exposure, local effects

LOAEC: 3 mg Cr(III)/m3

Dose descriptor starting point: 1.5 mg Cr(III)/m3

AF: 75 (default according to Reach Guidance R.8)

(3 LOAEC to NOAEC, 2 subchronic to chronic exposure, 2.5 interspecies and 5 intraspecies variability)

DNEL: 0.02 mg Cr(III)/m3

9.2.3 Sodium molybdate(VI) dihydrate, CAS 10102-40-6

While sodium molybdate(VI) dihydrate is a possible alternative to SD, also data on sodium molybdate(VI) (anhydrous, CAS: 7631-95-0) will be reported as toxicity is independent from water of hydration. Where toxicity is related to elemental Mo, no explicit reference is made in every instance to what exactly was the species used in the test.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 143 Classification

For sodium molybdate(VI), no harmonised classification according to Annex VI of the CLP Regulation is available. Sodium molybdate(VI) (anhydrous, CAS: 7631-95-0) is registered under REACH. In the registration dossier, it was recommended to not classify the substance. In addition, no classification was recommended in the joint entry of the classification and labelling inventory. Another group of notifiers recommended classification as follows:

Figure 9-4: Classification of disodium molybdate

Ecotoxicity

Existing reference values

Predicted no effect concentrations (PNECs) as derived according to ECHA-CHEM for sodium molybdate(VI) (anhydrous, CAS: 7631-95-0) are outlined in Table 9-5. These values are (on an elemental basis) identical to the ones available from ECHA-CHEM for MoO3 (CAS 1313-27-5), which 2- in aqueous solution is rapidly transformed to the molybdate ion (MoO4 ) according to the SIDS Initial Assessment Profile for Highly Soluble Molybdenum Salts (SIAP, OECD, 2013).

Table 9-5: Predicted no effect concentrations for different environmental compartments – values from ECHA-CHEM (sodium molybdate(VI) anhydrous) ECHA-CHEM, based on elemental Mo*

PNECfresh water 12.7 mg/L, AF 3, statistical extrapolation PNECmarine-water 1.9 mg/L, AF 3, statistical extrapolation PNECintermittent-releases not derived PNECSTP 21.7 mg/L, AF 10, assessment factor PNECsediment 22600 mg/kg sed. dw, EPM PNECsoil 9.5 mg/kg soil dw, AF 1, statistical extrapolation * values from ECHA-CHEM were recalculated based on a MW of 205.92 for MoO4Na2 (conversion factor 1/2.146)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 144 Derivation of PNECs by species sensitivity distribution is described in detail in the publication by Heijerick et al. (2012). All requirements according to REACH guidance R.10 (ECHA, 2008) are met. The additional assessment factor of 3 on the derived HC5-50% took account of a further NOEC not included in the distribution.

PNECSTP is derived by AF 10 from the 3-h EC10 value of an activated sludge respiration inhibition test according to the standard.

Discussion of suitability of reference values for comparative assessment

The PNECfreshwater of 12.7 mg/L (based on elemental Mo) as available from ECHA-CHEM is valid. Derivation of the value is outlined in detail by Heijerick et al. (2012). It is supported by experimental data summarised in the SIAP document (OECD, 2013) and the associated conclusion, that “Highly soluble molybdenum salts category substances do not present a hazard for the environment based on their low hazard profile.”

Based on the quite extensive data review provided within SIAP (OECD, 2013) we derived a provisional PNEC for the fresh water environment within this document using the AF method for chronic data based on three trophic levels as outlined in REACH guidance R.10 (ECHA, 2008) for comparison. A provisional PNECfreshwater derived on basis of the data review included in the SIAP document (OECD, 2013) of 4 mg/L could be derived, which is lower by a factor of 3 but of the same order of magnitude as the value reported in the registration dossier. This is due to the higher AF applied when using the AF-method.

With regard to STP microorganism toxicity, also the PNECSTP available from ECHA-CHEM is valid. It is based on the activated sludge respiration inhibition test, which is most widely accepted as an indicator for combined microbial inhibition in STPs.

Conclusions: PNECs for comparative assessment

The PNECfreshwater of 12.7 mg/L (based on elemental Mo) as available from ECHA-CHEM is valid and will be used for comparative assessment of sodium molybdate(VI) dihydrate as an alternative to SD.

Regarding sewage treatment plant microorganisms, the PNECSTP available from ECHA-CHEM of 21.7 mg/L (based on elemental Mo) is valid and will be used in the assessment of alternatives to SD.

Human toxicity

Existing reference values

Sodium molybdate dihydrate (CAS: 10102-40-6) itself is not registered under REACH, but the closely related sodium molybdate (anhydrous, CAS: 7631-95-0) is registered in the tonnage band of 1000- 10000 tons/year. The DNELs as derived according to ECHA-CHEM for sodium molybdate(VI) (anhydrous, CAS: 7631-95-0) are outlined in Table 9-6. Further information is given in the SIAP on highly soluble molybdenum salts (SIAP, OECD, 2013).

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 145 Table 9-6: Worker DNELs for sodium molybdate anhydrous (CAS 7631-95-0) – values from ECHA-CHEM (ECHA, 2014) Route of Systemic effects Local effects exposure Acute Long-term Acute Long-term Inhalation not derived 23.97 mg/m3 not derived not derived (about 11.2 mg Mo(VI)/m3) (effect) (repeated dose toxicity) Dermal not derived not derived not derived not derived (effect) * associated with an excess risk of 1 x 10E-5

No dose-response or assessment factor information is available for the DNEL derivation.

The information on repeated inhalation toxicity in the registration dossier is read across from data 2- on MoO3 (CAS 1313-27-5). As this substance is rapidly transformed to the molybdate ion (MoO4 ) in aqueous solution (SIAP, OECD, 2013), it was concluded that molybdenum trioxide can be used as read-across substance for the evaluation of systemic toxicity of molybdate. Information on repeated dose inhalation toxicity is based on the NTP study TR 462: Toxicology and Carcinogenesis Studies of Molybdenum Trioxide in F344/N Rats and B6C3F1 Mice (Inhalation Studies) (NTP, 1997). The 13- weeks study part of the NTP study (also the registration dossier) reports, both for rats and mice, no 3 chemical related lesions at concentrations up to 100 mg/m MoO3 (corresponding to 66.7 mg Mo(VI)/m³), the highest concentration tested (6.5 h/d, 5 d/w). However, there were significant increases in liver copper concentrations in female mice exposed to 30 mg/m3 and 100 mg/m³, as well as in male mice exposed to 100 mg/m³ compared to those of the control groups. Without any toxicological or histopathological correlate, these increases are not considered to be adverse (SIAP, OECD, 2013). Thus, the 13-week inhalation study on mice yielded a NOAEC of 100 mg MoO3/m³ (66.7 mg Mo(VI)/m³), and a NOEC of 10 mg MoO3/m³ (6.7 mg Mo(VI)/m³).

The chronic study was performed with concentrations of 10, 30 and 100 mg MoO3/m³. The NOAEC in this study was 10 mg/m3 (6.7 mg Mo(VI)/m³) with respect to alveolar inflammation in the rat. In addition, the study report documented a statistically significant and dose related hyaline degeneration of the nasal respiratory epithelium in all exposed females (0, 10, 30, 100 mg/m3: 1/48, 13/49; 50/50, 50/50), which was also evident in males, reaching the level of significance at 30 mg/m3 (2/50, 7/49, 48/49, 49/50).

The local effects observed in the respiratory tract following inhalation of MoO3 were considered in the SIAP (and obviously also by the authors of the registration dossier) as specific to MoO3 and were not read across to the soluble molybdenum compounds. Therefore the SIAP focused only on systemic effects, and the NOAEC value for systemic effects in rats and mice is 100 mg/m3 (66.7 mg Mo(VI)/m³).

Discussion of suitability of reference values for comparative assessment

No information was provided on the toxicological basis of the DNEL for long-term inhalation exposure of workers derived in the registration dossier. Based on the available information from the registration dossier it is assumed that the DNEL for systemic effects was derived on basis of the chronic toxicity study with molybdenum trioxide in rats and mice, which revealed a NOAEC of 100

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 146 mg MoO3/m³ (66.7 mg Mo(VI)/m³), applying a default overall assessment factor of 3 after conversion to a human equivalent concentration of 33.35 mg Mo(VI)/m³).

The underlying study is regarded valid. In line with the SIAP molybdenum trioxide is regarded a reasonable read-across substance for the assessment of systemic effects and the default procedure seems to be appropriate in the absence of substance specific data.

There are no data on repeated dose toxicity after dermal application of soluble molybdenum salts available. Dermal absorption can be considered low to negligible (about 0.2%) (SIAP, OECD, 2013).

The registration dossier and the SIAP report a reliable repeated dose rat feeding study (90 days study according to OECD guideline 408, extended for some reproductive endpoints, according to guideline 416). Rats were exposed to 5, 17, 60 mg Mo(VI)/kg bw/d, applied as disodium molybdate dihydrate. This study yielded a NOAEL of 60 mg Mo(VI)/kg bw/day regarding testicular, sperm and oestrous cycle effects. Due to reduced body weight in animals of the high dose group and slight kidney effects (slight diffuse hyperplasia of the proximal tubules) in two females of the high dose group the overall NOAEL is 17 mg Mo(VI)/kg bw/day.

A study from the fifties of the past century, cited by EPA IRIS (EPA, 2014), reports retarded weight gain in rats exposed to 2, 8 or 14 mg/kg bw/day as sodium molybdate dihydrate. This effect was not evident in the more actual studies, which are considered to be more reliable as the former data.

Further information on reproductive toxicity is available from an OECD guideline 414 developmental toxicity study with rats. Rats were exposed from day 6-20 of gestation to 0, 100, 338, 675, and 1350 ppm sodium molybdate(VI) dihydrate in the diet (corresponding to 0, 3, 10, 20 and 40 mg Mo(VI)/kg bw/d) no developmental or maternal effects were observed, resulting in an NOAEL for developmental and maternal toxicity of 40 mg Mo(VI)/kg bw/d (ECHA, 2014; OECD, 2013).

Under consideration of the calculation factors in ECHA guidance R.8 (ECHA, 2012b), the NOAEL of the developmental toxicity study can be converted to 70 mg Mo(VI)/m3, (40 mg Mo/kg bw/day : 4 (interspecies factor) x 70 kg bw : 10 m3 (respiratory volume per shift)) and supports the findings from the inhalation study which reported a NOAEC of 66.7 mg Mo/m3. If the NOAEL of 17 mg/kg bw/d from the 90-day oral toxicity study would be converted in a similar manner this would result in a ca. twofold lower NOAEC. However, without in depth evaluation of the original study report the toxic relevance of the effects in the high dose group, which were obviously not accompanied by histopathological alterations, remains unclear. Therefore, these data are not considered to be in contrast to the findings in the developmental toxicity and inhalation toxicity study.

There is no inhalation toxicity study available for soluble molybdates. According to the SIAP, local effects observed after inhalation exposure to molybdenum trioxide are not regarded to be predictive for soluble molybdates, because for local effects the strong acidification during the dissolution/dissociation reaction of molybdenum trioxide with water is considered to impart the unique irritation potential of molybdenum trioxide, which is probably not observed with soluble disodium molybdate. However, a final evaluation of possible local effects of disodium molybdate after inhalation exposure is not possible with the toxicity data at hand.

The NTP long-term study further reports a marginally positive trend for alveolar/bronchial adenoma and/or carcinoma in female rats (“equivocal evidence for carcinogenicity”) and increased incidences for alveolar/bronchial adenoma and/or carcinoma in male mice (“some evidence for carcinogenicity”), but MoO3 is not classified with respect to carcinogenicity, neither in the EU (see above) nor by EPA or IARC

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 147 Acute toxicity of disodium molybdate anhydrate is low. For the rat a dermal LD50 of > 2000 mg/kg 3 bw, an oral LD50 of 4233 mg/kg bw and an inhalation LC50 of 1930 mg/m has been reported (ECHA, 2014; OECD, 2013). None of the acute inhalation toxicity studies performed with several soluble molybdenum compounds including disodium molybdate revealed any toxic lesion of the lung (ECHA, 2014; OECD, 2013) indicating that disodium molybdate does not induce local effects after acute inhalation exposure.

In addition, no local effects were observed after application of several soluble molybdenum compounds, including disodium molybdate, to the skin or eyes. Therefore, it was concluded that disodium molybdate is not irritating to skin or eyes. In a guinea pig maximisation assay with disodium molybdate a negative result was obtained, i.e. disodium molybdate dihydrate was considered not to cause skin sensitisation (ECHA, 2014; OECD, 2013).

Conclusions: Tentative DNELs for comparative assessment

Based on the data documented above a tentative DNEL for systemic effects after long-term inhalation exposure was derived for molybdenum(VI) on basis of a 90-day repeated dose inhalation toxicity study performed with molybdenum trioxide (66.7 mg Mo(VI)/m3: NOAEC systemic effects effects). As there is no evidence for local effects after inhalation exposure, no such tentative DNEL is derived.

DNEL long-term inhalation exposure, systemic effects

NOAEC: 66.7 mg Mo(VI)/m3

Dose descriptor starting point (human equivalent concentration): 33.35 mg Mo(VI)/m3

AF: 25 (default according to Reach Guidance R.8)

(2 subchronic to chronic exposure, 2.5 interspecies and 5 intraspecies variability)

DNEL: 1.3 mg Mo(VI)/m3

9.2.4 Sodium Phosphates, CAS 7558-79-4 and 7558-80-7

Sodium phosphates in general are evaluated as (part) of a possible alternative to SD. REACH registered compounds are disodium hydrogen orthophosphate (CAS 7558-79-4) and sodium dihydrogen orthophosphate (CAS 7558-80-7), both of which are in equilibrium with each other in aqueous solution and the state of equilibrium solely depends on the pH of the solution. Therefore, they are assessed here together.

Classification

For sodium phosphates, no Harmonised Classification according to Annex VI of the CLP Regulation is available. In the registration dossiers of both substances no classification has been recommended. For disodium hydrogen orthophosphate (CAS 7558-79-4) and sodium dihydrogen orthophosphate (CAS 7558-80-7), classification according to classification and labelling inventory (highest to third highest number of notifiers including joint entry) is as follows:

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 148 Figure 9-5: Classification of disodium hydrogen orthophosphate and sodium dihydrogen orthophosphate

According to their respective joint entries (REACH registration), these compounds are not classified.

Ecotoxicity

Existing reference values

Beyond the REACH registration documents for disodium hydrogen orthophosphate (CAS 7558-79-4) and sodium dihydrogen orthophosphate (CAS 7558-80-7), no further assessment reports covering ecotoxicity could be identified.

REACH dossiers are identical for both compounds with regard to key studies for aquatic ecotoxicity including toxicity to STP microorganisms. In addition, the hazard assessment part (derived PNEC

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 149 values and assessment factors used) are identical. Therefore, both compounds are treated together as “sodium phosphates” without further discrimination.

Table 9-7: Predicted no effect concentrations for different environmental compartments – values from ECHA-CHEM ECHA-CHEM, sodium phosphates (CAS 7558-79-4 and 7558-80-7)

PNECfresh water 50 µg/L, AF 2000 PNECmarine-water 5 µg/L, AF 20,000 PNECintermittent-releases 0.5 mg/L, AF 200 PNECSTP 50 mg/L, AF 20 PNECsediment not derived PNECsoil not derived

No toxic effects were observed for both sodium phosphates in reliable acute tests with freshwater fish, aquatic invertebrates and algae (NOEC ≥ 100 mg/L). Also with sewage treatment plant microorganisms, the NOEC (3h) determined in a reliable activated sludge respiration inhibition test according to OECD 209 equals the limit concentration of 1000 mg/L. It is not clear, as to why for both compounds in deriving PNECs consistently 2fold higher assessment factors compared to those recommended by REACH guidance document R.10 (ECHA, 2008) were used (e.g. for aquatic PNEC based on acute data for three trophic levels AF of 2000 instead of 1000).

Discussion of suitability of reference values for comparative assessment

Aquatic PNEC values are based on acute aquatic studies for freshwater fish, green algae, and invertebrates, which are regarded as valid. These studies were used as basis for the derivation of the different aquatic PNEC values by applying different assessment factors. The PNECSTP is based on a reliable study on activated sludge respiration inhibition according to the standard. As discussed above it is not clear why generally two-fold higher assessment factors were applied for the derivation of the PNEC values than recommended by REACH guidance document R.10 (ECHA, 2008).

As the decisive PNECs suitable for comparative assessments are PNECfreshwater and PNECSTP these PNEC values were calculated using standard AF as given in REACH Guidance on Information Requirements and CSA, R.10 for comparison. The resulting values are:

PNECfreshwater: 100 µg/L

PNECSTP: 100 mg/L

Conclusions: PNECs for comparative assessment

PNECs used for comparative assessments are PNECfreshwater and – for risk assessment regarding sewage treatment plants – PNECSTP.

However, deviating from PNECs reported in the registration dossiers for both sodium phosphates, values derived using standard AFs according to REACH Guidance on Information Requirements and CSA, R.10 are used to provide for comparability of reference values across different compounds:

PNECfreshwater: 100 µg/L

PNECSTP: 100 mg/L

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 150 Human toxicity

Existing reference values

Disodium hydrogen orthophosphate (CAS 7558-79-4) and sodium dihydrogen orthophosphate (CAS 7558-80-7) are both registered in the tonnage band of 10,000-100,000 tons/year. Besides the REACH registration documents for disodium hydrogen orthophosphate (CAS 7558-79-4) and sodium dihydrogen orthophosphate (CAS 7558-80-7), there is an older JECFA evaluation on phosphoric acids and phosphate salts (WHO, 1982).

The DNELs as reported in ECHA-CHEM for disodium hydrogen orthophosphate and sodium dihydrogen orthophosphate are outlined in Table 9-8.

Table 9-8: Worker DNELs for disodium hydrogen orthophosphate (CAS 7558-79-4) and sodium dihydrogen orthophosphate (CAS 7558-80-7) – values from ECHA-CHEM (ECHA, 2014) Route of Systemic effects Local effects exposure Acute Long-term Acute Long-term Inhalation No-threshold effect 4.07 mg/m3 No-threshold effect and/or no dose-response and/or no dose- information available response information available (effect) Repeated dose toxicity (NOAEC), overall assessment factor: 140 Dermal No-threshold effect Exposure based No-threshold effect and/or no dose-response and/or no dose- waiving information available (effect) response information available * associated with an excess risk of 1 x 10E-5

Only a DNEL for systemic effects after long-term inhalation exposure was derived. The DNELs for both phosphates are identical. As there were no repeated dose inhalation toxicity studies reported in the registration dossiers the DNEL was obviously derived by route-to-route extrapolation on basis of an oral study. The key study for repeated oral exposure is a subchronic toxicity study with beagle dogs which, received sodium aluminium phosphate in concentrations of 0.3, 1.0 and 3.0% in the diet (corresponding to 94.23, 322.88 and 1107.12 mg/kg bw/d in males and 129.31, 492.77 and 1433.56 mg/kg bw/d in females). Due to nephrotoxicity observed in animals of the highest dose group (renal concretions) a NOAEL of 322.88 mg/kg bw/day was derived. The read across was considered to be justified by the authors of the registration dossier as observed toxicity effects were typical for phosphate but not for aluminium (‘Sodium aluminium phosphate is essentially a sodium orthophosphate that also contains an aluminium ion. Although aluminium is known to have toxic effects, the only systemic toxicity observed in the tests performed on sodium aluminium phosphate are not indicative of aluminium toxicity. The addition of aluminium in the phosphate compound is unlikely to have an impact on the use of this data for the sodium and potassium phosphates as any toxicity observed is due to the phosphate content of the test material.’)

The DNEL was derived by applying an overall assessment factor of 140. No further information was provided.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 151 Taking into account the different molecular weights for sodium dihydrogen orthophosphate and disodium hydrogen orthophosphate (see below) it is astonishing that identical DNEL values were presented in both registration dossiers. As DNELs are substance based, different numerical values should result for the two phosphates.

Discussion of suitability of reference values for comparative assessment

The DNEL for systemic effects after long-term inhalation exposure was based on an oral study, as there are no repeated dose toxicity studies after dermal or inhalation application for phosphates.

The DNEL was derived by applying an overall assessment factor of 140 and probably by conversion of an oral rat N(L)OAEL into a corrected inhalatory N(L)OAEC to assess human inhalatory exposure as presented in Figure R.8-3 of ECHA guidance R.8 (ECHA, 2012b). This seems to be an inaccurateness in the registration dossier, as the conversion for the rat was applied but not the correct conversion for dog data. It is not evident from the dossier how the assessment factor is composed.

Starting from a subchronic oral dog toxicity study a default procedure according to ECHA guidance R.8 (ECHA, 2012b) to derive a DNEL for systemic effects after long-term inhalation exposure of workers would be to convert the dog NOAEL of 322.88 mg/kg bw/day into a human equivalent air concentration (workers) of 1614.4 mg/m3 (NOAEL : 1.4 (allometric factor dog/man) x 70 kg bw : 10 m3/person). Applying an assessment factor of 50 (2.5 for remaining interspecies differences, 5 for intraspecies variability, 2 for extrapolation from subchronic study and 2 for route-to-route extrapolation), a DNEL of 32.23 mg sodium aluminium phosphate/m3 would result. As DNELs always refer to the registered substance the DNEL calculated for sodium aluminium phosphate has to be transformed into a DNEL for disodium hydrogen orthophosphate or sodium dihydrogen orthophosphate taking into account the molecular weights of these substances (144.94, 141.96, and 119.98 g/mol, respectively). This results in DNEL values of 31.57 mg/m3 and 26.7 mg/m3 for disodium hydrogen orthophosphate and sodium dihydrogen orthophosphate, respectively, or a DNEL of 21.1 mg phosphate/m3 or 6.9 mg phosphor/m3.

The reason for the discrepancy between the default calculation as presented above and the values in the registration dossiers remains unclear.

The study selected as key study for DNEL derivation seems to be reliable. Several older rat studies with different phosphates (mostly published before 1970) are reported in WHO (1982), where the lowest level of phosphate that produced nephrocalcinosis in rats was 1% P in the diet. This level was used as the basis for the evaluation by JECFA: Assuming a daily food intake of 2800 calories a dose level of 6600 mg P per day was calculated as the best estimate of the lowest level that might conceivably cause nephrocalcinosis in humans. WHO (1982) derived a Maximum Tolerable Daily Intake of 70 mg/kg bw as phosphor, which is equivalent to 271.2 mg/kg bw/day as NaH2PO4 or 327.6 mg/kg bw/day as Na2HPO4. In view of a high susceptibility of the rat to nephrocalcinosis (WHO, 1982), these data are in good agreement with the NOAEL of the dog study, used as key study in the registration dossier.

Acute inhalation toxicity has only been investigated with sodium dihydrogen orthophosphate. Rats were exposed to dust concentrations of 0.83 ± 0.065 mg/L (gravimetric concentration; nominal concentration 37.35 mg/L; maximum attainable concentration). No mortality was observed. During exposure lacrimation and squinting eyes were observed. Clinical signs noted following the exposure included chromodacryorrhea, lacrimation, nasal discharge and squinting eyes. No histopathological investigations were performed (ECHA, 2014).

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 152 Both phosphates are not classified as acutely toxic after oral or dermal exposure, as experimental investigations revealed LD50 values > 2000 mg/kg bw/d (ECHA, 2014).

Tests with both phosphates did not reveal any evidence of skin or eye irritating properties. No sensitising properties were observed in a Mouse Local Lymph Node Assay with sodium dihydrogen orthophosphate (ECHA, 2014).

Information on reproductive toxicity is available from an OECD Guideline 422 study in rats (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test) with dipotassium hydrogen orthophosphate tested at the limit dose of 1000 mg/kg bw/d. This study did not reveal any effect on fertility or offspring development. The NOAEL for fertility and developmental toxicity derived from this study is 1000 mg/kg bw/d. Developmental toxicity has been investigated with pregnant rats and mice, which received sodium dihydrogen orthophosphate on GD 6-15 by oral intubation in doses up to 410 and 370 mg/kg bw/d, respectively. No maternal effects or effects on the offspring were observed indicating that the highest dose tested can be regarded as NOAEL for developmental toxicity. Taking these data into consideration the NOAEL from the dog study seems also to be protective of possible reproductive toxic effects.

Conclusions: Tentative DNELs for comparative assessment

For a comparative risk characterisation of human health after inhalation exposure a tentative DNEL for systemic effects after long-term inhalation exposure was derived. The DNEL was derived by route-to-route extrapolation on basis of a 90-day repeated dose oral toxicity study with sodium aluminium phosphate in dogs (NOAEL of 322.88 mg/kg bw/day). In the absence of specific data 50% absorption after oral exposure and 100% absorption after inhalation exposure is assumed. Therefore, a route-to-route extrapolation factor of 2 is used for oral to inhalation extrapolation.

DNEL long-term inhalation exposure, systemic effects

NOAEL: 322.88 mg sodium aluminium phosphate/kg bw/day

Dose descriptor starting point (human equivalent concentration): 1614.4 mg sodium aluminium phosphate/m3

AF: 50 (default according to Reach Guidance R.8)

(2.5 remaining interspecies and 5 intraspecies variability, 2 subchronic to chronic, 2 route-to-route)

DNEL: 32.29 mg sodium aluminium phosphate/m3

Corresponding to

31.57 mg disodium hydrogen orthophosphate/m3

26.7 mg sodium dihydrogen orthophosphate /m3

21.1 mg phosphate/m3 or

6.9 mg phosphor/m3

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 153 9.2.5 Summary on hazard profiles of alternative substances

In Table 9-9, the tentative PNECs derived for SD and the alternative substances are summarised. It should be mentioned that none of the possible alternatives was classified for environmental toxicity hazards whereas SD is classified as very toxic to aquatic organisms after acute (H400) and chronic (H410) exposure. The higher toxicity is reflected in the PNECfreshwater, which is in a similar range as for chromium (III) but at least two orders of magnitude lower than those for phosphate buffer and sodium molybdate.

Table 9-9: Summary of tentative PNECs used for comparative assessment of sodium dichromate and alternative substances Sodium dichromate Chromium Sodium molybdate Phosphates 3- (Cr(VI)) trichloride (Cr(III)) (Mo(VI)) (PO4 ) PNECSTP [mg/L] 0.21 0.49 21.7 100 PNEC freshwater 0.0034 0.0047 12.7 0.100 [mg/L]

Table 9-10 summarises the tentative D(M)NELs for alternative substances used for the comparative assessment. The DMEL and DNEL for chromium (VI) and (III), respectively, are based on local effects as most critical endpoints. The DNELs for sodium molybdate and sodium phosphates are based on systemic effects, as there was no evidence of any local effects.

The DMEL for chromium (VI) (0.0000025 mg/m3, associated with a remaining risk of 1 x 10E-5) is substantially lower than the tentative DNELs used for the other substances. Additionally, it should be taken into consideration that none of the possible alternatives is classified for CMR endpoints. Whereas chromium (VI) and (III) may cause skin sensitisation neither sodium molybdate nor sodium phosphates were classified for skin sensitising properties.

Table 9-10: Summary of tentative worker DNELs long-term exposure used for comparative assessment of sodium dichromate and alternative substances Sodium dichromate Chromium Sodium molybdate Phosphate buffer 3- (Cr(VI)) trichloride (Cr(III)) (Mo(VI)) (PO4 )# Inhalation D(M)NEL – systemic effects n.d. 0.06 1.3 21.1 long-term [mg/m³] Inhalation D(M)NEL – local effects long- 0.0000025 0.02 n.d. n.d. term [mg/m³] n.d. not derived; the values marked in bold were used for the comparative risk assessment

9.3 Exposure Assessment

9.3.1 Comparative environmental Exposure Assessment

Exposure scenario for use as a processing aid in the production of sodium chlorate and chlorine dioxide

A scenario oriented on ERC4 (Industrial use of processing aids) but based on specific release fractions was used as outlined in Table 9-11.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 154 Table 9-11: Specific release fractions and STP parameters used for exposure estimation (ECETOC-TRA) Input parameter Value Unit Comment Daily amount used at site [Annual EU tonnage] *1000 / [Release kg default according to [kg/d] (release fractions) times per year] REACH guidance R.16 Release times per year 240 d worst case: 242 to 362 (d/year) for different sites Local release fraction to 0 no release to air air Local release fraction to 0.01 1% release to sewage sewage Local release fraction to 0 No direct release to soil soil Use of local STP (yes/no) yes Local STP with primary yes settler? Sludge to Soil? (yes/no) no The sludge is recycled, incinerated or sent to landfill River flow (m3/d) 18000 m3/d default according to REACH guidance R.16 Effluent discharge rate of 2000 m3/d default according to local STP (m3/d) REACH guidance R.16

Following REACH guidance R.7.13-2 (Environmental risk assessment for metals and metal compounds), the vapour pressure was set to a very low value (1*10-6 Pa). Estimations were performed on the elemental level (i.e. for Cr(VI), Cr(III) and Mo(VI), as also PNEC values were based on the element.

Input data for exposure modelling

Physico-chemical and environmental fate properties data for SD and alternative substances used for the exposure estimation are given in Table 9-12.

Table 9-12: Physico-chemical and environmental fate properties data for sodium dichromate and alternative substances (ECHA, 2014, if not stated otherwise)

Substance MW (g/mol) Kpsusp [L/kg] Kpsed [L/kg] Kpsoil [L/kg] Elimination Water STP solubility [mg/L] Sodium 51.996 (Cr) 2,000 1,000 50 (acidic) 50% adsorbed 2355 *103 dichromate (acidic) (acidic) 2 (alkaline) to STP sludge Cr(VI) (20°C) dihydrate 200 100 (ECB, 2005) 50% in effluent (ECB, 2005) (alkaline) (alkaline) (ECB, 2005): (ECB, 2005) (ECB, 2005) Kpsludge 3500 (54% sludge adsorption) Chromium 51.996 (Cr) 30,000 11,000 800 (acidic) 50% adsorbed 585 *103 (III) chloride (acidic) (acidic) 15,000 to STP sludge Cr(III) (20°C) hexahydrate 300,000 120,000 (alkaline) 50% in effluent (WHO, 2009) (alkaline) (alkaline) (ECB, 2005) (ECB, 2005): (ECB, 2005) (ECB, 2005) Kpsludge 20000 (82% sludge adsorption)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 155 Table 9-12: Physico-chemical and environmental fate properties data for sodium dichromate and alternative substances (ECHA, 2014, if not stated otherwise)

Substance MW (g/mol) Kpsusp [L/kg] Kpsed [L/kg] Kpsoil [L/kg] Elimination Water STP solubility [mg/L] Sodium 241.95; 2793 1778 871 Assumption: 654.2*103 molybdate 95.94 (Mo) (OECD, (OECD, (OECD, Kp raw SS, Kp (20°C) (VI) 2013) 2013) 2013) settled SS, Kp corr. to dihydrate activated SS, 259.41*103 Kp effluent SS (Mo) = Kpsusp Sodium 96.986 Chemical 107 (23°C) - phosphates (H2PO4 ) and/or biological phosphate elimination to approx. 0.5 – 1.0 mg/L STP effluent concentration

Sodium phosphates are used as buffer in combination with molybdate coatings and in combination with the processing aid sodium molybdate. In acute aquatic toxicity tests with sodium phosphates (sodium dihydrogen orthophosphate and disodium hydrogen orthophosphate) up to the limit concentration (100 mg/L) no toxic effects were observed. Based on the investigations up to the limit concentration a PNECfreshwater of 0.1 mg/L was derived for the phosphate compounds. This value is generally below the phosphate concentration, down to which phosphates are eliminated in STPs. I.e. comparing real phosphate concentrations with the PNECfreshwater will always result in RCRs > 1. Taking into account that huge amounts of phosphate are released into the environment by use of inorganic fertilisers and that phosphates are excreted from the human body a further quantification of phosphate exposure in the context of this use scenario will not be performed as the total amount released into the environment from this use is regarded negligible in comparison to the other phosphate sources. For example, the European Pollutant Release and Transfer Register reports that several hundred tons of total phosphorus are released per year into the single communal sewage treatment plants, whereas less than 1 ton phosphate/year would be needed per plant for this application. Further, phosphate is routinely reduced in sewage works to limit eutrophication of receiving waters. The resulting phosphate concentration leaving the STP is always above the

PNECfreshwater.

Assumed tonnages for the environmental exposure assessment are given in Table 9-13. Based on a realistic default amount of sodium dichromate dihydrate, relative amounts sufficient for replacement in the relevant process were chosen for the alternatives. Because the exposure estimation was performed on the elemental level, corresponding tonnage levels for the element are also given for convenience.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 156 Table 9-13: Assumed annual tonnages used for the comparative exposure assessment Based on the element Substance Estimated tonnage (tonnes/year) (tonnes/year) Sodium dichromate dihydrate 1.5 0.52 Chromium(III) chloride 2.7 0.52 hexahydrate Sodium molybdate(VI) dihydrate 2.4 0.95

These annual tonnages were calculated based on the knowledge on the molar concentrations of Cr(VI), Cr(III) and Mo(VI) necessary in the electrolyte for sodium chlorate production and using a realistic default assumption for the yearly amount of SD.

Specific considerations for sodium dichromate and chromium(III) chloride

Scenario for sodium dichromate

For the exposure estimation it has to be considered that chromium VI (Cr(VI)) is converted to chromium III (Cr(III) in the environment), the extent of which being dependant on prevailing environmental conditions (ECB, 2005). Under the conditions of acidic soils, sediments and waters (or neutral conditions with high concentrations of reductants) rapid reduction of chromium VI to chromium III is assumed, giving an estimated net result of 97% Cr(III) converted from Cr(VI) and 3% Cr(VI) remaining (ECB, 2005). However, under alkaline conditions (or neutral conditions with low concentrations of reductants) a slow rate is assumed for the reduction of Cr(VI) to Cr(III). This holds true e.g. for sea water (ECB, 2005). Correspondingly, for comparative risk assessment, we assume alkaline conditions as a worst-case scenario (100% Cr(VI), respective Kp-values for suspended matter, sediment and soil were used, see Table 9-12). Alkaline conditions as a worst-case scenario is substantiated by the following reasoning:

 Cr(III) is generally less ecotoxic compared to Cr(VI)  Cr(VI) is removed by adsorption to sludge to a considerable lower extent in STPs (approx. 50%) compared to Cr(III) (approx. 80%) (ECB, 2005), leading to a higher relative STP effluent concentration.

Because there are insufficient data to derive a PNECsediment from experimental studies, per default equilibrium partitioning is applied. Because this same method is applied for estimating concentrations in sediment, RCRs will by default be identical to the ones calculated for the freshwater department. Therefore, for comparison to possible alternatives no separate assessment of sediment will be performed. It has to be considered however that this is, again, a worst case assumption (same RCR for sediment like the one for freshwater), because the anoxic and reducing conditions in deeper sediment layers will actually lead to a rapid reduction of Cr(VI) to Cr(III).

Scenarios for chromium(III) chloride hexahydrate

Cr(III) is assumed to be essentially stable under environmentally relevant conditions, no transformation reactions to other redox states is assumed (100% Cr(III)).

For the purpose of comparison, two separate exposure estimations were performed, assuming acidic and alkaline conditions, respectively, and using respective Kp-values for suspended matter, sediment and soil (see Table 9-12). The considerably lower adsorption constants for suspended matter,

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 157 sediment and soil under acidic conditions leads to a higher RCRfreshwater (approximately factor of 4) compared to alkaline conditions. Therefore, as a worst case, PEC and RCR values calculated for acidic conditions are used for the further comparative assessment.

9.3.2 Comparative human exposure assessment

For an indicative comparison of occupational exposure, task 2 (sampling) was selected since this constitutes the task carried out most frequently (daily). SD and all alternatives are non-volatile so that modelling within ART (Advanced REACH Tool) reflects exposure to aerosol. If all other determinants, such as the transfer rate of the sampling solution, the room volume and the air changes per hour are identical (as assumed for this comparison) the exposure concentration estimated by the model is solely dependent on the concentration of the substance in the electrolyte solution and increases linearly with it. The task-based concentration shown in the following table was converted to a time-weighted average (TWA) concentration assuming exposure duration of 30 minutes.

Table 9-14: Comparison of occupational exposure during sampling Concentration of substance in electrolyte Concentration in air based on ART Substance solution modelling g/L %* Task-based [ng/m3] TWA [ng/m3] Use applied for: 1.77 (Cr(VI)) 0.126 (Cr(VI)) 11 0.69 sodium dichromate Alternative: chromium (III) 1.77 (Cr(III)) 0.126 (Cr(III)) 11 0.69 chloride Alternative: sodium 3.17 (Mo(VI)) 0.226 (Mo(VI)) 20 1.2 molybdate Alternative: 3 0.214 19 1.2 phosphate buffer * Calculated with a density of 1400 g/L assumed for the electrolyte solution; while this information is specific to current conditions, the same density was also assumed when the alternatives are used, since these are not expected to alter the density at these low concentrations

Overall, the higher concentrations of (some of) the alternatives in the electrolyte solution directly translate into higher exposure concentrations, but the difference is moderate (factor 1.8).

The same holds true for dermal exposure. As solids dissolved in liquids are outside the applicability domain of ECETOC TRA (ECETOC, 2012) a simplified calculation has been performed within the CSR for dermal exposure. Assuming that the handling of the substance would be comparable to the situation with SD the final result of dermal exposure depends on the concentration of the alternatives in the electrolyte solution, i.e. the relative dermal exposure between SD and the alternative would be comparable to the inhalation situation.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 158 9.4 Comparative risk characterisation

9.4.1 Results of comparative assessment

Ecotoxicity

Results of environmental exposure and risk assessment are given in Table 9-15. As mentioned above, RCR values for sediment are identical, because equilibrium partitioning is used to estimate both, PEC sediment and PNEC sediment. No terrestrial exposure is estimated, because there will be neither direct exposure of soil nor exposure by the sludge to soil pathway (sewage sludge is recycled, incinerated or sent to landfill).

Table 9-15: Local exposure concentrations and risks for the freshwater environment Exposure concentration (PEC), Compound, assumed environmental conditions RCR [mg/L] Sodium dichromate dihydrate as Cr(VI) 4.95E-04 1.46E-01 Chromium (III) chloride hexahydrate as Cr(III) 1.38E-04 2.95E-02 Sodium molybdate(VI) dihydrate as Mo(VI) 9.61E-04 7.57E-05

It must be emphasised that assumptions for release and exposure calculations are tentative and are not meant to represent real conditions at production sites. Rather, the assessment is meant to be comparative and assumptions are identical for all three compounds (with the exception that for both, sodium dichromate dihydrate and chromium(III) chloride, hexahydrate, worst case scenarios were calculated by assuming alkaline and acidic environmental conditions, respectively (see explanations above)).

Human Health

Table 9-16: Exposure concentrations and risks for workers exemplified for the sampling task Predicted D(M/N)EL Compound, assumed environmental Exposure Long-term, RCR conditions Concentration inhalation exposure [mg/L] [mg/L] Sodium dichromate dihydrate as Cr(VI) 0.69 E-07 0.0000025 0.276 Chromium (III) chloride hexahydrate as 0.69 E-07 0.02 3.45 x 10E-05 Cr(III) Sodium molybdate(VI) dihydrate as Mo(VI) 1.2 E-06 1.3 9.23 x 10E-07

31.57 Na2HPO4 Sodium phosphates 1.2 E-06 26.7 NaH2PO4 3.8-5.6 x 10E-08* 3- 21.1 PO4 3- *depending on the basis of comparison (Na2HPO4, NaH2PO4, or PO4 )

This comparison reveals that the alternatives would result in RCRs several orders of magnitude lower than the RCR for SD.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 159 9.4.2 Conclusions

For the comparative assessment of human health and environmental risks of SD and the alternative substances the following approach was used:

 Available reference values (DNELs, PNECs) were analysed  Where no reference values were available, which were derived by similar methodologies to allow for a comparison, tentative reference values were derived in this report (these values are for use for this comparative assessment only and are not intended to represent a full assessment of the substances concerned)  In order to be able to compare substances on a risk basis, an exposure scenario was established similar to the actual exposure scenario, but generic enough to be applicable to the alternatives  Exposure modelling input data were compiled for all substances  Exposure levels and risk characterisation ratios for the environment were calculated using ECETOC TRA  Exposure levels for workers were modelled with ART (Advanced REACH Tool).

Comparison of hazard data (classifications) reveals that none of the alternatives investigated are CMR substances and that none of the alternatives has been classified for environmental hazards.

The tentative risk characterisation shows that the alternative substances have lower RCRs for both human health endpoints (workers) and the environment.

Relevant uncertainties are associated with the rather generic exposure assessment applied here. However, differences between RCRs of SD and the alternative substances are at least one order of magnitude for all endpoints and therefore it can be reasonably assumed that this conclusion would hold true also under conditions of a refined exposure assessment.

It can be concluded that the alternative substances assessed in detail are beneficial with regard to human health considerations. Under the conditions of use assumed here also the comparative environmental risk characterisation leads to the conclusion that there is less risk associated with the use of the alternative substances.

In conclusion, the analysed alternative substances fulfil the requirement of leading to a reduction in overall risks to human health and the environment compared to the Annex XIV substance SD, based on the assumptions used here. 9.5 References for this Appendix

Derelanko, M.J.; Rinehart, W.E.; Hilaski, R.J.; Thompson, R.B.; Löser, E. (1999) Thirteen-week subchronic rat inhalation toxicity study with a recovery phase of trivalent chromium compounds, chromic oxide, and basic chromium sulfate Toxicological Sciences, 52, 278-288

ECB, European Chemicals Bureau (2005) European Union Risk Assessment Report: Chromium Trioxide, Sodium Chromate, Sodium Dichromate, Ammonium Dichromate, Potassium Dichromate. 3rd Priority List, Vol. 53. EUR 21508 EN. European Commission. Joint Research Centre

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 160 ECETOC, European Centre for Ecotoxicology and Toxicology of Chemicals (2012) Technical Report No. 114. ECETOC TRA version 3: Background and Rationale for the Improvements Brussels, Belgium

ECHA, European Chemicals Agency (2008) Guidance on information requirements and chemical safety assessment. Chapter R.10: Characterisation of dose [concentration]-response for environment http://guidance.echa.europa.eu/

ECHA, European Chemicals Agency (2012a) Guidance on information requirements and chemical safety assessment. Part E: Risk Characterisation. Version 2.0 Helsinki, Finland

ECHA, European Chemicals Agency (2012b) Guidance on information requirements and chemical safety assessment. Chapter R.8: Characterisation of dose [concentration]-response for human health. Version: 2.1 online: http://echa.europa.eu/documents/10162/17224/information_requirements_r8_en.pdf

ECHA, European Chemicals Agency (2014) Information on Chemicals - Registered Substances Online: http://echa.europa.eu/web/guest/information-on-chemicals/registered-substances

EFSA, European Food Safety Authority (2010) Scientific Opinion on the safety of chromium picolinate as a source of chromium added for nutritional purposes to foodstuff for particular nutritional uses and to foods intended for the general population. EFSA Panel on Food Additives and Nutrient Sources added to food (ANS) The EFSA Journal, 8(12):1883, 1-49

EPA, Environmental Protection Agency (2014) Integrated Risk Information System (IRIS) online: http://www.epa.gov/IRIS/

Hartwig, A. (2009) Gesundheitsschädliche Arbeitsstoffe, Toxikologisch-arbeitsmedizinische Begründungen von MAK- Werten, Loseblattsammlung, 46. Lfg DFG Deutsche Forschungsgemeinschaft, WILEY-VCH Verlag Weinheim

Heijerick, D.G.; Regoli, L.; Carey, S. (2012) The toxicity of molybdate to freshwater and marine organisms. II. Effects assessment of molybdate in the aquatic environment under REACH Science of the Total Environment, 435–436, 179-187

NTP, National Toxicology Program (1997) Toxicology and Carcinogenesis Studies of Molybdenum Trioxide in F344/N Rats and B6C3F1 Mice (Inhalation Studies). TR 462 U.S. Department of Health and Human Services; Public Health Service

OECD, Organisation for Economic Co-Operation and Development (2013)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 161 SIDS Initial Assessment Profile for Highly Soluble Molybdenum Salts. CoCAM 5, 15-17 October 2013 http://webnet.oecd.org/hpv/ui/handler.axd?id=7584FAAE-4CC2-41F1-AEDD-E3134ACB47A7

Rhodes, M.C.; Hébert, C.D.; Herbert, R.A.; Morinello, E.J.; Roycroft, J.H.; Travlos, G.S.; Abdo, K.M. (2005) Absence of toxic effects in F344/N rats and B6C3F1 mice following subchronic administration of chromium picolinate monohydrate Food and Chemical Toxicology, 43, 21-29

WHO, World Health Organization (1982) Toxicological Evaluation of Certain Food Additives and Contaminants. Twenty-sixth Meeting of the Joint FAO/WHO Expert Committee on Food Additives. WHO Food Additives Series, No. 17

WHO, World Health Organization (2009) Concise International Chemical Assessment Document No. 76. Inorganic Chromium(III) Compounds Geneva, Switzerland

WHO, World Health Organization (2013) Concise International Chemical Assessment Document No. 78. Inorganic Chromium(VI) Compounds Geneva, Switzerland

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 162 10 Appendix 3 – Economic feasibility

The AoA has found that, with the exception of chromium(III) chloride, no alternative to sodium dichromate has been found to be technically feasible and that for this reason the alternative cannot have any economic feasibility for the applicant. This section explores the situation should the alternatives be assumed to have technical feasibility and the economic feasibility assessed based on the claims made in the R&D. 10.1 Economic feasibility of sodium molybdate

Investment costs for the implementation of the alternative

There are two key investment costs for switching from SD to sodium molybdate:

 Access to technology and R&D: Kemira will have to undertake further R&D work before it is capable of switching to sodium molybdate, as discussed earlier, or acquire rights of access to a third party’s R&D on the technology. '''' ''''''''''' '''' ''''''''''''' ''''''''#E#''' ''''''''''''' ''''''''' ''''''' ''''''''' ''''' ''''''''''''''''''' ''''''''' ''''' ''''' '''''' ''''''' '''''''''''''''''''

 Plant conversion costs: there are four key steps under this:  Disposal of existing electrolyte: the implementation of sodium molybdate would, at a minimum, entail replacing the existing electrolyte brine solution that contains Cr(VI) with a new brine solution containing sodium molybdate and buffer. The existing brine solution that contains Cr(VI) would need to be disposed of. In addition, after the removal of the chlorate SD-rich solution, pipes and tanks must be washed; this washing water would contain a lower concentration of Cr(VI) and would still require disposal

The overall volume of electrolyte to be replaced and the volume of wash waters that would be generated from the purging of the system at Kemira’s three plants are shown in the following table.

Table 10-1: Volume of electrolyte to be replaced and of waste waters to be disposed of by the applicant for the implementation of sodium molybdate ''''''''''''''' '''' ''''''''''' ''''''''''''' ''''''''''' ''''' '''''''''' '''''''''''''''' ''''''''''''' '''' ''''''''#A#''''''''''''' '''' ''''''' ''''''''''''' ''''' '''''' '''''''''''' '''' ''''' ''''''''''''''' ''''''''''''''''''' '''''''''' '''''' ''''''''''' '''''' ''''''''''''''''' ''''''' '''''' ''''''' '''''' '''''''''''''''''''''''' ''''''' '''''' '''''''' '''''' ''''''''' ''''''''' '''''' ''''''''''' '''''' ''' '''''''' ''''''''''' '''''''''' '''''''''''' '''''''' '''''''' ''''''''''''''''' ''''''''''''''''' ''''''''''''''' ''''''''' '''''''''''' ''''''''''' ''''''' ''''''''''''''''''''''''' ''''''''' ''''''

The above volumes are very large and thus it would be impossible for the applicant to send such large volumes of SD-containing solutions to any outside treatment plants – treatment needs to be made on-site. The procedure to handle the SD-containing solution is to reduce SD to Cr(III) by a reducing agent (such as Fe(II) or sulphite, etc.) and separate the sludge and

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 163 send it to a hazardous waste treatment plant. Both SD-rich (electrolyte) and low-SD waste (wash waters) are to be treated in this fashion, the key difference being the amount of sludge formed.

The associated costs would include the following: (a) construction of treatment plants including contaminated & treated solution (temporary) storages. Both the contaminated and treated solutions will require storage and treated solution might then be returned to the plant. The cost of a treatment plant is difficult to estimate with certainty, but the capital expenditure must be understood to lie above the €#D# million mark for each plant. Any such plant would need storage tanks for contaminated solutions, a storage tank for the reduction reaction, precipitator reactors, a sludge settler, a sludge filter, a sludge storage and treated solution storage; and (b) the cost of disposal of the Cr-containing sludge by an external contractor. The estimated total amount of Cr-containing sludge would be around '''''#A#'''' tonnes of dry solids and '''#A#'''' tonnes of wet solids. An estimated treatment cost of €''''#D#'''''/t (wet solid) gives a total cost of €''''''''#D#'''''''' million. The overall cost of disposal of the electrolyte and of the washing of the system to be over €'#D#' million, dominated by the cost of installing treatment plants at each location

 Preparation of a new electrolyte: the new electrolyte would need to be generated and would comprise sodium chlorate, sodium molybdate and phosphate buffer.

Literature suggests that a sodium molybdate concentration of 8 g/L (Li, et al., 2007) would be needed. Taking into account the volume of electrolyte used by the applicant ('''''#A#''''' m3 in total), this electrolyte would require ''' '''''''''' ''' ''''''#D#'''' '''''''' ''' ''''' tonnes of sodium molybdate to make up a new solution.

Sodium phosphate buffer would also be required due to the poorer buffer range fit of sodium molybdate in comparison to SD. Based on the patent held by Industrie De Nora 3- (Krstajic, et al., 2007), it is assumed that around 3 g/L of phosphates (32 mmol of PO4 ) would be required to provide an effective buffer in a chlorate electrolyte. This concentration can be achieved by addition of various sodium phosphate salts, such as sodium dihydrogen 3- orthophosphate. In order to achieve this concentration of phosphate (PO4 ), 4.9 g/L (32 mmol) of sodium dihydrogen orthophosphate dihydrate (NaH2PO4·2H2O) is required or ''''''' ''' '''''''' ''' ''#D#'''''''' ''' ''''''''''' ''' '''''' ''''' tonnes when taking into account the electrolyte volume ('''''#A#''''' m3 in total).

In addition, a concentration of sodium chlorate of 550 g/L would need to be achieved (see Table 2-1). Taking into account the volume of electrolyte required (''''#A#''' m3 in total), the quantity of sodium chlorate needed would be ''''''' '' ''''''''' '''#D# '''''' '' ''''''''' ''' '''''''''''' tonnes of fresh sodium chlorate.

In order to convert these into costs, the following information can be used: (a) Table 10-4 shows that the median market price of sodium molybdate is ca. €11,000/t; (b) Table 10-5 shows that the median market price of phosphate buffer can be taken at ca. €950/t; and (c) the production cost for sodium chlorate is given in Table 5-5 and stands at €'''#C#''''/t. Therefore, the total cost for generating the new electrolyte would be (''''' ''' '''''''''#D#'''''''' ''' ''''''' '' '''''''''''' '' ''''''''''' ''' '''''''''' ''' ''''' ''''''''''' million.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 164 If a higher concentration of sodium molybdate (100 mM (Gustafsson, et al., 2012), -3 equivalent to 100 mmol/L = 100 × 205.92 × 10 = ca. 20.6 g Na2MoO4 per L) would be required in order to achieve technical feasibility, the cost of making up the new electrolyte would increase to ('''''''''' ''' '''''''' ''' '''''''''' ''' #D#'''''''''''' ''' '''''''''''''''' ''' ''''''' ''' ''''''''''' ''' '''''''''''' ''' '''''''''' ''' '''''' ''''''''' million

 Downtime: the time required for the aforementioned actions could be ca. 5 weeks, on the assumption that electrodes would not need to be replaced. '''''''' '''''''''''''''''''''''' ''''' ''''''''''''''' ''''''''''' '''' '''''''' '''''''' '''''' ''''''''''' '''''' ''''''' '''''''''''''''' ''''''' '''''''''''''' '''''' '''''''''''''''''''' '''''''' '''' '''''''''''''''' '''' '''''''''' '''''''' '''''' '''''''' ''''''''' ''' ''''''''''''' '''''' ''''''' ''#G#''''''''' '''''''''''' '''' ''''''''''''' '''''''''' ''''' '''''''''''''''''' '''''''''' ''''''''' '''' '''''' ''''''''''''''' ' '''''''''' '''''' ''''''''''''''''' '''''''' ''''''''''''''' ''''''''''' ''' ''''''' ''''''''''''''''''''''' '''''''''' '''''''''' '''''' ''''''' ''''' '''''''''''''' ''''''''''''''''''''''' '''''' '''''''''''''''''' ''''''''''''''''' ''' '''''''''''''''' ''' '''''''''' ''' '''''' '''''''' ''''''''''''' A 5-week downtime would mean two things: (a) 1/10 of the annual turnover might be lost. This would represent ca. €'''#C#'''' million in turnover and €''''#C#''''' million in profit; and (b) fixed costs over the same period would still be incurred. To provide an indication of this cost, we may consider the on-going costs presented in Table 10-3. Of the cost elements included in that table, the following may be considered fixed costs that would continue even during a period of downtime: Salaries, Costs of meeting worker health and safety requirements, Costs associated with equipment downtime for cleaning or maintenance, Insurance premiums, Marketing, license fees and other regulatory compliance activities, Other general overhead costs (e.g. administration)23. The applicant cannot provide details of all these cost elements (which are clearly minor in comparison to energy costs), but for those that data can be provided, an overall €''#C#'''/t of sodium chlorate can be assumed (salaries, health and safety, cleaning/maintenance). Over 1/10 of a year, the associated fixed costs would be: €''''' ''' #D#'''''''''''''' × 0.1 = €'''#D#''''' million. Therefore, the overall cost of downtime over 5 weeks would be ''''''' #D#'''''''' = €'#D#' million

 Improvement of oxygen controls: the introduction of N2 gas purging would require investment costs for altering the equipment used for purging and the compression of hydrogen. This cost has not been estimated yet as the sodium molybdate technology is not considered technically suitable. For the purposes of this analysis, it is assumed that this change would be completed within the 5-week period indicated above. The applicant currently sells part of the hydrogen produced at the Joutseno plant but also uses hydrogen internally in the manufacture of sodium borohydride.

As noted above, a total period of downtime of 5 weeks is assumed. During this period, sodium chlorate production would cease and operations that are linked to the production of sodium chlorate would also be affected. The following table summarises the affected operations and the associated affected turnovers.

23 Clearly some of the other variable costs would still be incurred during downtime (i.e. the plant will still consume some electricity, water, etc.) but for simplicity, this is disregarded.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 165 Table 10-2: Kemira’s operations that would be affected during downtime Implications from downtime of the chlorate cells Turnover in Location Description of operation Stoppage of 2013 production/ Details sales? XXXXXXXXXXXXXXX XXXXXXXXXXXXX Sodium borohydride XXXXXXXXXXXXXX manufacture using H from 2 '''''''' #C#'''''''''' Yes XXXXXXXXXXXXX the chlorate plant as raw XXXXXXXXXXXX material Sastamala XXXXXXXXXXXX XXXXXXXXXXXX XXXXXXXXXXXXXXXXX Sales of pressurised hydrogen '''''''''''''''''''' Yes XXXXXX Use of H for steam 2 '''''''' Yes production XXXXXXXXXXXXXXX XXXXXXXXXXXXXXX HCl manufacture at the XXXXXXXXXXXXXXXX nearby chlor-alkali plant using XXXXXXXXXXXXXXXX H2 from the chlorate plant ''''' ''''''''''''' Yes XXXXXXXXXXXXXXX Joutseno XXXXXXXXXXXXXXXX XXXXXXXXXX XXXXXXXXXXXXXXXXXX Sales of pressurised hydrogen ''''''''''''''''''''''' Yes XXXXXXX Use of H for steam 2 ''''''' Yes production Total turnover potentially affected over 5- '''''''''' ''''''''''''' weeks of downtime (10% of annual)

Operating costs

There are many elements that contribute to operating costs, but as already noted, energy is the main cost of the production process. The following table presents the range of different operating cost elements and provides a comparison of the costs arising under SD and under sodium molybdate. This table has been jointly developed for the members of the consortium of sodium chlorate manufacturers, but where appropriate the information has been replaced with applicant- specific information, which is claimed as confidential.

Table 10-3: Comparison of operating costs for production of sodium chlorate between sodium dichromate and sodium molybdate Current process cost in € per tonne of Change due to use of sodium Operating cost category sodium chlorate molybdate product Energy costs for producing 1 tonne of sodium chlorate Electricity ''''''''' #C#'''''''''''' '''''#D#''''''''' (+9.9%) for electrolysis '''''''''' for buying in electricity

Gas (by-product H2) ''''' '''''''''''' ''''''''''''' for replacing heating generated with H2 from the chlorate cell

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 166 Table 10-3: Comparison of operating costs for production of sodium chlorate between sodium dichromate and sodium molybdate Current process cost in € per tonne of Change due to use of sodium Operating cost category sodium chlorate molybdate product Materials and service costs for producing 1 tonne of sodium chlorate Cost of SD ''''''''''' '''''''''' (+1170%) for molybdate salt '''''''''''''' for addition of phosphate buffer Raw materials (salts, additives, etc., excluding ''''''' '''''''''''' ''' ''''''''''''''''' ''''''''' for nitrogen used in purging water and sodium dichromate) '''''''' ''''''''''''' Water Minor No change expected Environmental service costs (e.g. waste Minor Elimination of Cr(VI) in sludge, but treatment and disposal services) waste would still be hazardous Transportation of product to customer '''''''' ''''''''''' No change expected Replacement parts and any other materials ''''' ''''''''''' Increased cost for anode needed for the operation of the plant recoating/replacement due to the presence of phosphates Labour costs for producing 1 tonne of sodium chlorate Salaries, for workers on the production line '''''''' '''''''''''' No change expected (incl. supervisory roles) Costs of meeting worker health and safety Minor No major change expected requirements (e.g. disposable gloves, masks, etc.) Maintenance and laboratory costs for producing 1 tonne of sodium chlorate Sampling, testing and monitoring cost (incl. lab ''''''''''' Short-term cost increases for worker cost) sampling and monitoring; unclear maintenance requirements Costs associated with equipment downtime for '''''' ''''''''''' Cost increases likely due to more cleaning or maintenance (incl. maintenance frequent anode recoating/ crew costs) replacement Other costs for producing 1 tonne of sodium chlorate Insurance premiums '''''''''''' Additional costs cannot be quantified Marketing, license fees and other regulatory ''''''''''''' Reduced with respect to REACH compliance activities regulation (no need for an Authorisation) Other general overhead costs (e.g. ''''''' No change expected administration) Overall costs (% change) '''''''#C#'''''' ''''''''''''' ''''''''#D#''''''' ''''''''''''''' * Assuming electricity consumption is directly proportional to cost

Energy cost: Kemira does not consider sodium molybdate as a technically feasible alternative to SD and they cannot estimate their specific costs with certainty. As described in the above section on technical feasibility, the use of sodium molybdate would result in a 9.9% increase in electricity consumption (from 5,230 kWh/t theoretical to 5,746 kWh/t theoretical). If it is assumed that the cost of electricity is directly proportional to consumption, this also represents a 9.9% increase in the cost of electricity. If we also assume that ''#C#''% of the total production cost of sodium chlorate for Kemira is due to electricity, the total increase in production cost would be #D#% due to electricity

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 167 for electrolysis alone. In money terms, a 9.9% increase in energy costs would translate into a production cost increase of €''''''' ''' '''''#D#''''' ''' '''''''''' per tonne of sodium chlorate.

In addition, the hydrogen generated from the chlorate reaction is used internally by Kemira for the generation of heat. The total fuel value of Kemira’s H2 used in heating is '''#C#''' MWh/y. This would need to be replaced by an external energy source (a mixture of H2/N2 would burn inefficiently). If light oil were to be used (at a price of €'''#D#''''/t), the additional cost would be €''#D#'' million/y; if natural gas were to be used (at a price of €'#D#'/MWh), the cost would be €'#D#' million/y (this is possible in Joutseno). Assuming that natural gas were to be used, the production cost increase would be €'''#D#''' million ÷ ''''''#B#''''''' t = €'''#D#''''/t sodium chlorate

Moreover, in Joutseno ''''''#C#'''''' MWh worth of H2 is used to produce ''''''#C#'''''''' MWh/y electricity. Obtaining this from the grid would attract an additional cost of €'''#D#''' million/y or €''#D#''/tonne sodium chlorate (for simplicity, it is assumed that this cost would be shared among the entire Kemira chlorate operations. i.e. all three plants).

The total increase in energy costs would therefore be €'#D#' + €'#D#' + €'#D#' = ca. €'#D#'/t. This increase in energy costs would therefore increase the total cost of production from €#C# to ca. €#D# per tonne of sodium chlorate. ''''' '''''''' ''''''' '''''''''''''''''#B# & #D#'/ '''' ''''' ''''''' ''''''''''''''''''' ''''''''' '''''' ''''''' ''''''''''''''''''' ''' '''' ''''''''''''' '''''''''''''''''''''''' ''''''' ''''''''''''''''' ''''''''''''' ''''''''''''''''' '''''''''''''''''''' ''''''''''''''' '''''' ''''''''''''''''''' ''' '''''''''''''''''' '''' ''''' '''' '''''''''''''' '''''''''''''''' ''''''' ''''''''''' ''''' ''''''' '''''''''''' '''''' '''''''''''''''''' ''''''''' '''' '''''''''''''''''''''' '''''''''''' ''''''''''' '''''' ''''''''''''''''' '''''''' ''''' '''''' '''''''' '''''''''''''' ''''''' ''''''''''

Material and service costs: other process cost components are generally minor and it would not be expected that most of them would change significantly with the use of sodium molybdate. The following may be noted:

 Cost of sodium molybdate: the cost of the additive itself however would change. Publicly available price data is provided in Table 10-4 This suggests a price of ca. €11,000 per tonne, significantly higher than the assumed price for SD of €1,540/tonne. If it is assumed that SD is used at 4.5 g/L of electrolyte (mid-range of 3-6 g/L in the BREF) and that sodium molybdate is used at 8 g/L of electrolyte as proposed by Li et al (2007) and that the average prices of SD and sodium molybdate are €1,540/t and €11,000/t respectively, then the percentage increase in additive per litre of electrolyte is ca. 1170%. As noted earlier (under the discussion on CrCl3), given the consumption of SD of ''#B#''' kg/t sodium chlorate, the consumption of sodium molybdate would be 8/4.5 = 1.78 times higher than SD, or '#D#' kg per tonne of sodium chlorate. With an annual production of sodium chlorate of '#B#' kt, the additional annual cost from the replacement of SD by sodium molybdate would be ca. €''#D#'' per year or €'#D#' per tonne of sodium chlorate. This is clearly much lower than the main cost element of increased energy consumption

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 168 Table 10-4: Cost of sodium molybdate (Alibaba.com, 2 April 2014) Minimum Supply Source Location Purity order Price (€/t) (FOB) ability (t/y) quantity (t) 1 China 99 600 0.1 8,786-10,250 2 China 99 800 0.001 10,982-18,304 3 China 99 24,000 1 9,225-10,250 4 China 99 18,000 0.1 8,786-10,103 5 China 99 5,000 0.001 5,857-13,179 6 China 99 500 0.001 7,321-21,964 7 China 99 1,200 0.1 13,179-18,304 8 China 99 6,000 0.001 8,786-13,179 9 China 99.5 5,000 0.001 7,321-14643 10 China 99 3,600 1 10,982-21,964 11 China 99.9 3,000 0.001 10,250-14,643 Range (€/t) 5,857-21,964 Average price (€/t) 12,194 Median price (€/t) 10,982

Table 10-5: Cost of sodium dihydrogen orthophosphate dihydrate (Alibaba.com, 2 September 2014) Minimum Supply Source Location Purity order Price (€/t) (FOB) ability (t/y) quantity (t) 1 China 98% 10,000 1 763-1,525 2 China 98-99% 600 1 771-1,125 3 China 99% 3,000 20 991-1,085 Range (€/t) 763-1,525 Average price (€/t) 1043 Median price (€/t) 948

 Cost of phosphate buffer: the use of sodium molybdate as an alternative would require the addition of additional buffer, due to the poorer buffer range fit of sodium molybdate in comparison to SD. Based on the patent held by De Nora (Krstajic, et al., 2007), it is assumed 3- that around 3 g/L of phosphates (32 mmol of PO4 ) would be required to provide an effective buffer in a chlorate electrolyte – it must be noted that such a very high concentration (by typical standards in electrolytic cells, would have significant adverse effects on the durability of the anodes (Kus, 2000). This concentration can be achieved by addition of various sodium phosphate salts, such as sodium dihydrogen orthophosphate. In order to achieve this 3- concentration of phosphate (PO4 ), 4.9 g/L (32 mmol) of sodium dihydrogen orthophosphate dihydrate (NaH2PO4·2H2O) is required. The rate of consumption of the phosphate is not known but it can be assumed to be similar to the replacement of the electrolyte as a whole. Therefore, assuming that the rate of consumption of SD is #B# t/y (or '''''' '''#B#'''' g/y) and that SD is used at a concentration of 4.5 g/L (or 4.5 × 103 g/m3) of spent electrolyte, this would mean that (''''''#B#'''''' g/y) ÷ (4.5 × 103 g/m3) = ''''#D#''' m3 of electrolyte is replaced each year by the applicant. Therefore, to achieve the required phosphate concentration of 4.9 g/L (see discussion of the make-up of the new electrolyte), a total of (4.9 g/L) × (''''#D#'''' m3) = ca. #D#' tonnes per year of sodium dihydrogen phosphate dihydrate would be required. At the median price shown in Table 10-5, this amounts to some €'''''#D#''''''' per year or €'''#D#''''' per tonne of sodium

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 169 chlorate produced (using a sodium chlorate tonnage of ''#B#''''' kt/y). Clearly, this is a very minor additional cost element.

 Cost of environmental services: it might be construed that the environmental service costs could decrease because there would no longer be a need to dispose of Cr(VI)-containing sludge. However, the amount of hazardous waste would arguably not decrease. The same amount of sludge would be formed and due to the presence of NaClO3 the waste would remain hazardous even in the absence of dichromate.

 Cost of inputs for control of oxygen evolution: there would also be an increase in costs due to the need to provide nitrogen gas to limit the oxygen concentration in the hydrogen. The total consumption of nitrogen will depend on the dilution ratio. For instance, the total maximum H2 flow from all Kemira plants is ''''''#C#''''''' Nm3/h or ''''#C#''''''''' m3/h '''' '''''' '''''#A#'''''' '''''' ''''. To 3 dilute the O2 content to 50% (i.e. from 4% down to 2% in H2) ''''''#D#''''''' Nm N2/h would be needed or ''''''#D#'''''' Nm3/y or '''''#D#'''' t/y24. The estimated cost of purchasing this amount of nitrogen gas is €'#D#' million/y or an additional €'#D#'/t sodium chlorate (for a chlorate production of '''#B#'' kt/y). This is a very significant increase to the production cost of sodium chlorate.

Moreover, the use of N2 purging with the aim to control the concentration of O2 in H2, would have an impact on the quality of hydrogen, where the generated hydrogen is used in further reactions. As discussed above, hydrogen is used for hydration at Kemira’s Sastamala plant and for the formation of HCl at the nearby chlor-alkali plant in Joutseno, while both plants also sell some of their produced hydrogen to a third party. '''''''' ''''''' ''''' ''''' ''''''''''''' '''''''''''' '''''''''' ''''''' '''''''' '''' ''''''' '''''''''''' '''' ''''''''' '''''''''''''' ''''''''''''''''''' ''''''''''''''''' ''''' '''''''''''''''' ''''''''''#C#''' '''''''''' '''''''' '''''''''' ''''''' '''''' ''''''''' ''''''''''''''' '''''''''' '''''' '''''''''''''' ''''''''''''' '''''''''''''''''''' '''''''''' '''''' ''''''''''''''''' '''''''''''' '''''''''''' '''''''''' '''' ''''' '''''''''''''''''' The following table shows the operations that would be affected and the respective turnovers. To be able to use the hydrogen for other purposes, a substantial investment is needed for gas cleaning which is currently not necessary. This has not been costed yet as the alternative clearly lacks technical feasibility.

Table 10-6: Kemira operations that would be affected by potential inability to use the generated hydrogen Implications from downtime of the chlorate cells Turnover in Location Description of operation Stoppage of 2013 production/ Details sales? ''' '''''''' '''''''''''''' '''' ''''' '''''''''''' ''''' ''''''''''''''' '''''''' '''' ''''''' Sodium borohydride '''''''''''''''''''''''' ''''' ''''''''''''''''' manufacture using H from the ''''''#C#''''''' Sastamala 2 '''''''''''''''' '''''' '''''''''''''''''''' chlorate plant as raw material ''''''''''''''''' ''''''''''''' '''''''''' ''''' ''''' '''''''''''''''''''''' Sales of pressurised hydrogen ''''''''''''''''''''''' Yes '''''''''''' ''''''' ''''' '''''''' ''''' '''''' '''''

24 Volume conversions were performed using this calculator: http://www.gulfcryo.com/customer- support/conversion-tables-gas.html (accessed on 24 November 2014).

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 170 Table 10-6: Kemira operations that would be affected by potential inability to use the generated hydrogen Implications from downtime of the chlorate cells Turnover in Location Description of operation Stoppage of 2013 production/ Details sales?

Use of H2 for steam production '''''''' Yes '''''''''''''''''''' '''''''''''''''''''' '''''''''''''''' ''''''''''''' ''''''''' ''''' '''''''''''''''''' '''''''''''''''' '''''''''''''' ''''''''''''' ''''''''' ''''' ''''' '''''''''''''''''''' '''' ''''''''''''' ''''''' ''''''''''''''' ''''''''' ''''''''' '''''''''''''''''''' '''''''''' '''''''''''''' HCl manufacture at the nearby ''''''''''''''''''''''''''' '' '''''''''''''' chlor-alkali plant using H from 2 '''''''''''''''''''''' ''''''''''' ''''' the chlorate plant ''''' '''''''''''' Yes Joutseno '''''''''''''''''' ''' ''''''''''''''' '''' ''''''''''''' '''''''''' ''''''''''''''''''''''''' '''''' '''''''''' '''' '''''''''''' ''''''' '''' ''''''''''''''''' ''''''' ''' ''''''''''' '''''''''''''' '''''''''''''''''''' '''''' '''''''''' '''''''' '''''' ''''''''''''' '''''''''' ''''''' '''''''''''''''''''''' ''''''''''''''''' ''''''''''''' '''''' ''''' ''''''''' ''''' '''''' Sales of pressurised hydrogen ''''''''''''''''''''''' Yes ''''''

Use of H2 for steam production ''''''''' Yes Total turnover potentially affected ''''''''' '''''''''''''

 Replacement parts: anode recoating and replacement is likely to occur more often due to the possible need to add phosphate. This cost has not been quantified.

Labour costs: no real changes would arise in labour costs.

Maintenance costs: the long term-effect of sodium molybdate and phosphate buffer on the lifetime of electrodes and equipment has not been evaluated, as the applicant is not aware of any scale-up trials that would allow this to be evaluated. In the short term, the cost of sampling and monitoring the process could be foreseen to increase in order to gain further process experience. Following this, it is expected that the significantly adverse effects of increased concentrations of phosphates on the anodes would require more frequent replacement of the anodes, thus increasing the overall cost of maintenance operations.

Other costs: if sodium molybdate and phosphate were used in high concentrations to avoid any use of Cr(VI), there would be a reduction in the cost of meeting REACH Regulation requirements as future Authorisation applications would be avoided. Finally, the increased generation of oxygen (to be controlled by N2 purging) would clearly increase the explosion hazard profile of the plant and this could affect the insurance premiums for the applicant. All these administrative costs are not possible to quantify, but are likely to be lower than the key cost of increased energy consumption and the cost of nitrogen for purging.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 171 Conclusion and required steps to make the alternative economically feasible

The use of sodium molybdate (in conjunction with phosphates) is clearly an economically infeasible alternative. Apart from the cost of further developing and implementing this alternative, its use would increase the cost of energy by a significant margin. In addition, the use of nitrogen purging would further increase the overall production cost due to the large volumes of nitrogen needed. These cost increases would have a serious impact on the profitability of Kemira’s operations. When sodium molybdate is used, the production cost increases from €#D# to ca. €#D# per tonne of sodium chlorate. The price at which the applicant is selling sodium chlorate is assumed to be, on average, €'#C#' per tonne. ''''''' '''''''''''''''''''''' '''''''' '''''''''''''''' '''''''''#D#''''''''' ''''''' '''''''''''''''''''''' '''' ''''''''''''''' ''''''''''''''''''''' ''''''''''''' '''''''''''''''' '''''' ''''''''''''' ''''''''''' ''''''''''''' '''' '''''''''''' ''''''' ''''''''''''' '''''''''' '''''' '''''''''''''''''''''' ''''''''''''''' '''''''''''''''' ''''''''''''''''''''''' It must be noted that not all cost increases have been quantified; therefore, this is a conservative estimate. Sodium chlorate is a commodity chemical available from both EU-based and non-EU suppliers and is sold on the basis of margin and logistics. Its commodity nature of the chlorate means that passing on the additional production cost to customers would be very difficult. Moreover, ancillary operations that rely on the hydrogen gas released from the chlorate reaction would be impacted. ''''''' '''''''''' ''''''''''''' '''''#D#''''''''''''''''' ''''''''' '''' ''''''' '''''''''''''''''' ''''''''''''' '''''''''' ''''''''''''''''''' '''''''''''' '''''''''''' '''' ''''''' ''''''' '''' ''''''''' '''''''' ''''''''''''''''' ''''''''''''''''' '''''''''''''''''''''' ''''''''' '''''' '''''''''''''''''''''''' ''''' ''''''''''''''' ''''''''''''''''''''''''' '''''''' '''''''' '''''''' ''''''''''''''''' ''''''''' '''' ''''''''' '''''''''''''''

Unless the R&D identifies, develops and scales up the use of sodium molybdate at an optimal concentration and, potentially, in the presence of additives which help control the increase in energy consumption and oxygen generation without the need for a phosphate buffer at high concentrations, it would appear impossible to substantially improve the economic feasibility of this alternative. 10.2 Economic feasibility of molybdenum-based coatings

Investment costs for the implementation of the alternative

There are two key investment costs for switching from SD to molybdate-coated cathodes:

 Access to technology and R&D: the molybdenum-coated cathodes technology is far from being mature as it has not been successfully demonstrated at a scale relevant to the commercial production of sodium chlorate. Therefore, R&D further to what is currently published will be required before this technology could be implemented on the applicant’s plants. If such technology that can deliver SD-free chlorate production is patented by a third party, the cost of obtaining the rights to the patent would need to be factored in but it is impossible to estimate at present. ''''' ''''''''''' '''' ''''''''''''''' ''''''''''' '''''''''''''' '''''''#E#''' ''''''' '''''''''' '''''' '''''''''''''''''''' '''''''' '''''' '''''' '''' ''''''' '''''''''''''''''''''''

 Plant conversion costs: there are six key steps under this:  Disposal of existing electrolyte: as in the case of the implementation of sodium molybdate, the replacement of the existing electrolyte brine solution that contains Cr(VI) with a new brine solution containing buffer would be required. The existing brine solution that contains Cr(VI) would need to be disposed of. In addition, after the removal of the chlorate SD-rich solution, pipes and tanks must be washed; this washing water would contain a lower concentration of Cr(VI) and would still require disposal. The volumes of the systems in each of Kemira’s plants were provided in Table 10-1. Following the argumentation provided for sodium molybdate, the overall cost of disposal of the electrolyte and of the washing of the

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 172 system to be over €#D#' million, dominated by the cost of installing treatment plants at each location

 Preparation of a new electrolyte: the new electrolyte would need to be generated and would comprise: sodium chlorate and phosphate buffer. Following the calculations made earlier for the replacement of SD by sodium molybdate, the total cost for generating the new electrolyte would be (''''' ''' ''''''''''' ''' ''''''''#D#''' ''' '''''''''''' ''' '''''' '''''''''''' million

 Plant downtime: in order to begin using this technology, all of the electrodes and cathodic boxes (electrolysers) would need to be replaced. '''''''' '''''''' '''''''''''''' ''''' '''''''''''''''''''''''''''''' '''' '''''''''''''''''''' '''' ''''' '''''''''''' '''''''''''''' ''''''''''' ''' ''''' '''''''''''' ''''''''''''' '''''' ''''''' '''''''''' '''' ''''''''''''''''''''''''' '''''''' ''''''''''''''' '''''''''''''''' ''''' '''''''''''''''''''''''''''''' ''''''''' ''' '''''''' ''' ''''''' '''''''''''''''' '''''''''''''''' ''''''''''''''''''' ''''''''' ''''''''''''' '''''''''''''''''''''''''' ''''''' ''''''' ''''''''' '''''''''''''''' '''' ''''''''''''''''''''''''' '''' '''''''''''''''''' ''' ''''''' '''''''''''''''''''' ''''''''''''''''''''''''' '''' ''''''''''''''''''''' '''''#C#''' ''''''''''''''' ''''''' ''''' ''' '' ''''''''''''''' '''''''''''''''''''''' '''' ''''''''''''''''''''''''''' '''''''' '''''''''' '''''' '''''''''''''''''' '''' ''' ''''''''''' ''''''' ''''''' ''' ''''''''' ''' '''''''''''''' '''''''' '''' '''''''''''''' '''' '''''''''''''''''' '''''''''''''''''''''' '''''''''''''''''' ''''''''' '''''' ''''''''' ''''''''''''''''' ''''''''''' '''''''''''''''' '''' ''' '''''''''''''''''''' '''''''''''''''''' '''''''''''''''''''''' ''' ''''''''' ''''' '''''''''''' ''''''''''''''''' '''''''' ''''''''''''' '''''''''''''''' ''''''''' ''''''''''''''''' ''''''''''''''''''' '''''''''''''''''' ''''''''''' ''''''' '''''''''''''''''''''''''' ''' ''''''''''''' '''' ''''' '''''''''''' '''''''''''''''''' ''''''' ''''''''''''''''''''''' '''' ''' '''''''''' '''''' ''''''' '''''' '''''''''''''''''''''' '''' '''''''''''''''''' '''''''''' ''''' '''''' '''''''''''''''''''''''''''''' However, upon a refused Authorisation, it would not be possible to gradually change the electrodes because it is unlikely that their operation would be compatible with the existing conditions employing SD (R&D in a pilot plant would be required to confirm this). If the existing electrode packages were replaced with molybdenum-coated cathode ones in ‘one go’, this would be an operation that has not been undertaken before and would require (a) a considerable amount of worker-time to carry out and (b) a significant period of downtime. In normal operation, the cathodes are changed periodically, with each electrode assumed to be changed every 8 years on average (for cathode minimum lifetime years see Section 2.2.5' ''''''' ''''''' ''''''' ''''''''''''''''#C#''''' ''''''''''' '''''' ''' '''' ''''''''' '''''''''''''). Therefore, the electrodes would need to be replaced as quickly as possible to minimise plant downtime. Consultation with the consortium of sodium chlorate manufacturers has indicated that downtime may take 3-6 months. A 3-6 month downtime would mean two things: (a) a reduction in chlorate production caused equivalent to a loss of ca. '''''#D#''''''' kt of chlorate for the applicant (based on a sales volume of '''#B#'''' kt/year). This would reduce turnover by ca. €'''''''''#D#'''''' million. Based on a profit margin of ''#D#''% '''''''' '''''' '''''''''#D#'' ''''''''''''''' '''''''''''''''''' as mentioned above, the lost profit during downtime from loss of sodium chlorate sales alone would be ca. €''#D#'''''' million; and (b) fixed costs over the same period would still be incurred. Following the approach taken for sodium molybdate in Section 5.3.3, over a period equivalent to 25-50% of a year, the associated fixed costs would be between €''''' #D#'''''''''''' × 0.25 = €''#D# million and €XXX#D#X × 0.5 = €''#D#'''' million. Therefore, the overall cost of downtime would be between '''''''' ''''#D#'''' ''''''''''' million

 Acquisition of replacement equipment: the cost of materials (new electrodes) is challenging to estimate due to the experimental nature of the technology in its current state. It is also not known whether it would be best to replace either the cathodes boxes alone or the entire electrolysers. We hereby provide a simple calculation of the cost of replacing the cathodes. '''''''' ''''''''' ''''''''''''' '''' '''''''''''''''''' '''''''' '''''''''''' ''''''''' ''''' ''''' ''''''''''''''''' ''' ''''''''''''' ''''''' '''''' ''''''' ''''''''' '''' ''''''''''''''''''''''''' '''''''''''''''' '''''''''' '''#D#'''' ''''''''''''''' ''''''''''''''' ''''''''''''''''''''''''''''' '''''' '''''''' ''''' '''''''''''''''' ''''''' ''''''''''''''' ''''''''''''''''''''' '''''''' ''''''''''''''''''''''' '''''''''''' ''''''''' ''' '''''''''''''''''''''''' ''''''' '''''''

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 173 '''''''''''''''' ''''''' ''''''' '''' '''''''' ''''''''' ''''''''''''''''''' '''''' ''''''''''''''''''' '''''''' '''' ''''''' ''''''''' '''''''''''''''''''' '''' ''''''''' ''' '''''''''''''' ''' '''''' '''''''''''''

 Cost of installing new equipment (engineering cost): it is assumed that the applicant would aim to replace all cathodes within the timeframe of the aforementioned downtime, i.e. 3-6 months, and this would include the activation of the new cathodes. This cost has been quantified at €'''#D#''' million, as shown in the table below.

Table 10-7: Estimate of installation costs for the new molybdenum-coated cathodes Plant Duration Man-power required Man-hours required '''''#D#''''' ''' ''''''''''''''' ''''''''' ''''''''''''''''' ''' '''''''' '''''''''''''''' '''''' ''''''''''' '''''''''''''''' ''' '''''''''''''' '''''' '''''''''''''''' '' ''''''' ''''''''''''''''' '''''' ''''''''''' '''''''''''''''''''''''' ''' '''''''''''''' '''''' '''''''''''''' ''' '''''''' '''''''''''''''''' '''''' '''''''' ''''''''' ''''''''''' '''''' '''''''''''''' ''''''''' ''''''' '''''' '''''''''''' ''''' '''''''' '''''''''''''

 Impacts on ancillary operations: other integrated facilities would also suffer downtime or impaired operational conditions. For the applicant these include the manufacture of HCl in Joutseno from by-product hydrogen at the nearby chlor-alkali plant and the manufacture of sodium borohydride in Sastamala where hydrogen produced as by-product is further used as raw material. Hydrogen sales would also be affected. On the basis of the information shown in Table 10-2, cessation of production of sodium chlorate and generation of hydrogen over 3-6 months, could mean that a total turnover of €'''#D#''''' million from ancillary operations would also be affected ''''''''''''''''''''''''' '''#D#'''' '''''''''' '''' '''''''''''''''''''.

Finally, the control of oxygen evolution might need to be improved, possibly through the use of N2. The changes required have not been costed as it is not clear what intervention would in fact be needed.

Operating costs

There are many elements that contribute to operating costs, but as already noted, energy is the main cost of the production process. The following table presents the range of different operating cost elements and provides a comparison of the costs arising under SD and under the use of molybdate-coated cathodes. This table has been jointly developed for the members of the consortium of sodium chlorate manufacturers, but where appropriate the information has been replaced with applicant-specific information, which is claimed as confidential.

Table 10-8: Comparison of operating costs for production of sodium chlorate between sodium dichromate and molybdate-based cathode coatings Current process cost in € per tonne of Change due to use of Operating cost category sodium chlorate chromium(III) chloride product Energy costs for producing 1 tonne of sodium chlorate Electricity ''''''''#C#' ''''''''''' ''''#D#'''''''' (-17%)*

Gas (made by by-product H2) Minor No change envisaged

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 174 Table 10-8: Comparison of operating costs for production of sodium chlorate between sodium dichromate and molybdate-based cathode coatings Current process cost in € per tonne of Change due to use of Operating cost category sodium chlorate chromium(III) chloride product Materials and service costs for producing 1 tonne of sodium chlorate Cost of SD '''''''''' '''''''''''' - Assumed that no SD would be required (this has not been proven yet). '''''''''''''' for addition of phosphate buffer Raw materials (salts, additives, etc., excluding '''''''' ''''''''''' ''' '''''''''''''''' No change envisaged water and sodium dichromate) ''''''' '''''''''''''' Water Minor No change envisaged Environmental service costs (e.g. waste Minor Elimination of Cr(VI) in sludge, but treatment and disposal services) waste would still be hazardous Transportation of product to customer ''''''' '''''''''''' No change envisaged Replacement parts and any other materials ''''' ''''''''''' Increased cost for anode needed for the operation of the plant recoating/replacement due to the presence of phosphates Labour costs for producing 1 tonne of sodium chlorate Salaries, for workers on the production line '''''''' ''''''''''''' No change envisaged (incl. supervisory roles) Costs of meeting worker health and safety Minor No significant change envisaged requirements (e.g. disposable gloves, masks, etc.) Maintenance and laboratory costs for producing 1 tonne of sodium chlorate Sampling, testing and monitoring cost (incl. lab ''''''''''' Increased until sufficient process worker cost) experience has been gained Costs associated with equipment downtime for ''''' ''''''''''' Unknown cleaning or maintenance (incl. maintenance crew costs) Other costs for producing 1 tonne of sodium chlorate Insurance premiums '''''''''''' No change envisaged Marketing, license fees and other regulatory '''''''''''' Reduced with respect to REACH compliance activities regulation (no need for an Authorisation) Other general overhead costs (e.g. '''''''' No change envisaged administration) Overall costs (% change) '''''#C#'''''''' ''''''''''' '''''''#D#'''''''''' ''''''''''''' * Assuming electricity consumption is directly proportional to cost

Energy cost: as already discussed in the above section on technical feasibility, the use of molybdenum-based coatings has the theoretical potential to reduce the energy consumption of the process by 17% (from a theoretical 5,230 kWh/t down to 4,342 kWh/t). In the absence of information from the use of the technology at the industrial scale, we may apply this reduction to the electricity bill for the applicant. This, would suggest that production costs could reduce by €''''''' '' ''''''''#D# ''' '''''''''' per tonne of sodium chlorate produced, representing a reduction of overall production costs of ''#D#'% or a cost saving of €''''''''' '' '''#D#'''''' ''' '''''''''''' million/y. This is clearly a

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 175 theoretical calculation because the technology has not been proven at the industrial scale and should not detract from the fact that implementation of the technology would require a very significant investment cost.

Cost of materials and service costs: the initial cost of materials has been discussed above. Additional on-going costs (or savings) would include:

 Savings from the non-use of SD: a minor saving would be made from the elimination of purchases of SD (for the ''#B#'' t/y consumed per year, an estimate cost of €''''#D#''/y or €'#D#'/t sodium chlorate would be saved based on an assumed market price of SD of €1,540 per tonne)

 Cost of phosphate buffers: as described above for sodium molybdate, sodium phosphate buffer at a concentration of 4.9 g/L would need to be employed in the electrolyte. Using the same approach the cost of additional buffer on a yearly basis can be expected to be €'''''#D#'' per year or around €''#D#'''''' per tonne of chlorate produced

 Cost of environmental services: it might be construed that the environmental service costs could decrease because there would no longer be a need to dispose of Cr(VI)-containing sludge. However, the amount of hazardous waste would arguably not decrease. The same amount of sludge would be formed and due to the presence of NaClO3 the waste would remain hazardous even in the absence of dichromate

 Cost of inputs for control of oxygen evolution: there might also be an increase in costs due to the need to provide nitrogen gas to limit the oxygen concentration in the hydrogen. As discussed above, the generated hydrogen is used for making HCl in Joutseno and in manufacturing sodium borohydride in Sastamala. It is also used for the generation of heat and electricity. ''' '''''''' '''''' '''''''''''''''' '''''''' '''''' ''''''' '''' ''''' '''''''''''''' ''''''''''' ''''''''''' '''''' ''''''' ''''' '''''''''''''''''' '''''''''''''' ''''''' ''''''' '''''''''' '''''''''''''' '''''''' ''''' ''''''' '#D#'''''''''''''''''''' '''' ''''''''''''''' '''''''''''''''''''''''' ''''''' ''''''' '''''' '''''''' '''''''''''' ''''''' '''''''''''''''''''' '''' ''''''' '''''''''''''''' ''''''''''''''''' ''''' '''''''''''''''''''' ''''''''''''' '''' '''''''''''' '''''''''''' '''''''''' ''''' '''''' ''''''''''''''' As shown in Table 10-2, the total turnover of ancillary operations that would be affected if the hydrogen supply were to be affected is '''''''' ''''''''''''''#D#' '''''''''''''''''' '''''''''''''''''' ''''''''''. The associated economic impacts have been described in relation to the potential use of sodium molybdate and the reader is referred to that discussion. Given the uncertainty over whether such oxygen controls would indeed accompany this alternative, this estimate of the impacts on ancillary operations/revenue streams is only indicative

 Replacement parts: anode recoating and replacement is likely to occur more often due to the possible need to add phosphate. This cost has not been quantified.

Labour costs: no significant changes are envisaged.

Maintenance costs: there are no data available on the likely lifetime of molybdenum-coated cathodes, as the technology has not yet been demonstrated.

Other costs: if this technology were to be technically feasible and avoid any use of Cr(VI), there would be an elimination of the cost of meeting REACH Regulation requirements, as future Authorisation applications would be avoided. On the other hand, if the applicant needed to obtain a licence for using patented technology developed by a third party (as noted earlier, Industrie De Nora have filed a patent application (Krstajic, et al., 2007) which, as of 14 October 2014, does not appear

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 176 to have been granted yet25), this may have require the ongoing payment of fees. These are not possible to estimate at present.

Conclusion and required steps to make the alternative economically feasible

As this technology is unproven with a third-party patent application on this technology pending, the discussion on its economic feasibility can only be a theoretical one.

Even if the very significant technical hurdles were to be overcome with additional research and scale up of the technology, which would certainly require a significant time, a sufficiently long transition/conversion period would be needed for the orderly gradual replacement of electrode units that respects the typical electrode lifetime at a sodium chlorate plant. If such a conversion period would not be available, the costs associated with an accelerated cathode replacement would be very significant, as it would result in loss of production and sales of sodium chlorate. For the applicant, the cost of downtime and of the replacement of the existing cathodes would amount to several millions of Euros. Revenues from ancillary operations would also be affected during conversion with a significant turnover potentially lost in the assumed 3-6 months of downtime. These very high upfront costs make this, yet unproven, technology economically infeasible.

With regard to operating costs, if assertions made in a relevant published patent application prove correct and if elimination of Cr(VI) were to become possible, this technology could reduce production costs. However, this has not been proven at the industrial scale and any reliance on these claims would certainly be premature. Irrespective of the potential changes in energy consumption, the periodic replacement of anodes would be necessary due to their impaired durability in the presence of significant concentrations of phosphates. Moreover, if there was a need for better controls on oxygen evolution, the costs associated with such controls (cost of N2 purging and impacts on ancillary operations) could seriously impact upon the applicant’s profitability and revenue streams.

These costs make this – yet unproven – technology economically infeasible. 10.3 Economic feasibility of two-compartment electrolytic systems

Investment costs for the implementation of the alternative

There are four key investment costs for switching from SD to two-compartment electrolytic systems:

 Access to technology and R&D: Kemira would have to undertake further R&D work before it is capable of successfully implementing the two-cell technology, even if the technology were to be developed by a third party and then be available for licensing. An estimate of such cost cannot be provided at present

 Building a new plant: the existing single-cell electrolysers would become obsolete and would need to be replaced. A new membrane-based two-compartment plant similar to a chlor-alkali plant would need to be constructed at each production location. Essentially, the implementation of a new plant by Kemira would involve the replacement of its existing facilities.

25 Based on the data available at the European Patent Office, https://register.epo.org/application?number=EP06819847 (accessed on 14 October 2014)

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 177 This would involve the decommissioning of its three existing facilities followed by reconstruction of new facilities. Kemira estimates that to build new production capacity of ca. '''#B#'''' kt in Finland would cost approximately €'''#D#''' million. This is for totally new production plants. Whether existing equipment could be used in the new plants would require a detailed analysis and study. On the other hand, to avoid long pauses in production, the existing plants would need to be running while the new plants would be built. At locations where Kemira may have space on its production sites (Sastamala and Joutseno), it might be possible to construct a site while the existing chlorate plant is in operation. Where space is not available (Kuusankoski), there would be a significant period of shutdown while the existing site is demolished and a new chlor- alkali type plant constructed. Additionally, during the period of demolition-construction, the turnover made from ancillary operations described in Table 10-2 would be lost. Importantly, the duration of the construction phase would be substantially long so that impacts on ancillary operations could be much more severe than in the case of sodium molybdate or molybdenum- coated cathodes

 Worker training: there would be a requirement to retrain workers in the operation of a new and unfamiliar plant

 Existing equipment/plants becoming redundant: as noted above, the existing sodium chlorate plants of Kemira would need to be replaced and past investment would be lost.

The above discussion shows that the investment costs for the conversion to this alternative technology are extremely high.

Operating costs

There are many elements that contribute to operating costs, but as already noted, energy is the main cost of the production process. The following table presents the range of different operating cost elements and provides a comparison of the costs arising under SD and under the use of the two- cell technology. This table has been jointly developed for the members of the consortium of sodium chlorate manufacturers, but where appropriate the information has been replaced with applicant- specific information, which is claimed as confidential.

Table 10-9: Comparison of operating costs for production of sodium chlorate between sodium dichromate and two-compartment electrolytic cells Current process cost in € per tonne of Change due to implementation of Operating cost category sodium chlorate two-cell technology product Energy costs for producing 1 tonne of sodium chlorate Electricity '''''''''#C# ''''''''''' '''''''''''''' #D#''''''''''''''''''*

Gas (made by by-product H2) Minor No change envisaged Materials and service costs for producing 1 tonne of sodium chlorate Cost of SD ''''''''''' ''''''''''' - Cost of SD eliminated Raw materials (salts, additives, etc., excluding ''''''' '''''''''''' – including Uncertain water and sodium dichromate) salt freight Water Minor No change envisaged Environmental service costs (e.g. waste Minor Reduced due to lack of Cr(VI) treatment and disposal services) sludge disposal costs

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 178 Table 10-9: Comparison of operating costs for production of sodium chlorate between sodium dichromate and two-compartment electrolytic cells Current process cost in € per tonne of Change due to implementation of Operating cost category sodium chlorate two-cell technology product Transportation of product to customer '''''''' ''''''''''''' No change envisaged Replacement parts and any other materials ''''' ''''''''''''' Significant increase due to needed for the operation of the plant replacement of cell membrane (every 2-5 years) Labour costs for producing 1 tonne of sodium chlorate Salaries, for workers on the production line '''''''' ''''''''''''' Initial training requirement but no (incl. supervisory roles) change over continued operation Costs of meeting worker health and safety Minor No significant change envisaged requirements (e.g. disposable gloves, masks, etc.) Maintenance and laboratory costs for producing 1 tonne of sodium chlorate Sampling, testing and monitoring cost (incl. lab Minor No change envisaged worker cost) Costs associated with equipment downtime for ''''' '''''''''''' Significant increase over cleaning or maintenance (incl. maintenance conventional process due to crew costs) replacement of cell membrane Other costs for producing 1 tonne of sodium chlorate Insurance premiums ''''''''''' No change envisaged Marketing, license fees and other regulatory ''''''''''' Reduced with respect to REACH compliance activities regulation (no need for an Authorisation) Other general overhead costs (e.g. '''''''' No change administration) Overall costs (% change) ''''''#C#''''''' '''''''''''''''' '#D#'''''''''''''''' '''''''''''' * Assuming electricity consumption is directly proportional to cost

Energy consumption: the energy consumption of the sodium chlorate process would increase substantially and, as this is the major cost component for the production of sodium chlorate, it will also have a significant impact on the overall cost of the process. This alternative process could be expected to use approximately of 5,880 kWh/t chlorate produced in electricity (see calculation made earlier). This would mean an increase of 650 kWh/t over the current theoretical 5,230 kWh/t consumption or 12.4%.

If other costs are disregarded, a 12.4% increase in energy costs alone would result in a #D#'% overall increase in the production cost of sodium chlorate for Kemira or ca. €''''#D#'' per tonne of sodium chlorate. The additional cost of €''#D#''/tonne would mean an additional cost of ca. €#D# million per year. ''' ''''''''' '''''''''''''' '''' ''''''''''''''#D#''''''''' '''''''''' '''''''''''''''''' ''''''''''' '''''''' ''''''''''''''''' '''''''''' ''''''''''''''''''''''' ''''''''''''' '''''' '''''''''''''' '''''''''' '''''''''''' '''' ''''''''''''' '''' ''''''''''''

Materials and services: a minor saving would be made from the elimination of purchases of SD (for the '''#B#''''' t/y consumed per year, an estimate cost of €'''#D#''/y or €'''#D#''''''/t sodium chlorate would be saved).

On the other hand, maintenance costs would also rise, as the operation of a membrane chlor-alkali cell is more expensive than undivided chlorate cells. This is due to the relatively low service life of

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 179 the membrane. According to the chlor-alkali BREF, the membrane needs to be replaced every 2-5 years (IPPC, 2001), in addition to this, the electrodes will need periodic replacement, as is the case for undivided cells.

Labour costs: no significant changes are envisaged.

Other costs: other costs would likely stay similar to the current process employing SD with the exception of reduced REACH compliance costs for Authorisation.

Conclusion and required steps to make the alternative economically feasible

The use of the two-cell production technology is clearly an economically infeasible alternative. Apart from the cost of further developing and optimising this alternative, its implementation would require the demolition of existing plants and the building of new plants. A preliminary assessment of the cost of this engineering work would suggest a cost of €''''#D#'''' million, to obtain plant of a capacity similar to the existing chlorate plants.

Even if the building of new plants could be financed, the operation of the new plants would be hindered by the considerable increase of the most important production cost component, energy consumption by 12.4%, which would increase Kemira’s overall production cost by ca. '''#D#''''%. Furthermore, the cost of electricity is expected to rise in the future (EC, 2013) and as such, this cost component will only increase in importance.

As mentioned earlier, sodium chlorate is a commodity chemical available from both EU-based and non-EU suppliers and is sold on the basis of margin and logistics. '''''''''''' ''''''''''''''''''''''''''''''' ''''''''''''''''''''' ''' ''''''''''' ''''''' ''''''''''''''''''''' '''''''' ''''''''''''''''' ''''''''' '''''''''' '''' ''''''''' ''''''' ''''''''''' '''' '''''''''''''' ''''''''''''''' ''''''' ''''''''' ''''' '''''''''''' ''''''#D#' ''''''''''''''''' '''''''' '''''''''' ''''''''''''''' ''''''''''''''' '''' '''''''''' ''''''''''''''''' ''''''' '''''''''''' ''''' ''''''''''''''' ''''''' ''''''''''''''''''''' ''''''''' '''''''''''''''' ''''''''''''''''' ''''''' '''''''''''''''''''' '''' ''' ''''''''''''''''''''''''''''''''' '''''''''''''''''''''' ''''''' '''''''''''' ''''''''''''' ''''''''''''' '''' '''''''' ''''''''''''' ''''''' ''''''''' '''' ''''''''''''' ''''''''' '''''''''' '''''''''' ''''''''''' '''' ''''''''''''' '''''''''''''''' '''''''''''' ''''''''' '''''''''''''' '''''' ''''''''' '''' ''''''''''''''''' ''''''' ''''''''''' The commodity nature of the chlorate means that passing on the additional production cost to its customers would be very difficult.

The need to construct new plants at a very high cost, couple with an increased cost of production renders this alternative clearly economically infeasible for Kemira in both the short and longer term.

Use number: 1 Legal name of applicant(s): Kemira Chemicals Oy 180