PI gress R P rt to
Metro Recovery Systems (MRS) 2430 Rose Place Roseville, MN 55113
Minnesota Office of Waste Management Industrial Waste Reduction Grant Program
REDUCTION OF CHROMIUM PLATING WASTES
Task 7 FINAL REPORT
Michael Wismer, Technical Manager, MRS and Malcolm T. Hepworth, Consultant
November 9, 1990
MINERAL RESOURCES RESEARCH CENTER DEPARTMENT OF CML AND MINERAL ENGINEERING
UNIVERSITY OF MINNESOTA TABLE OF CONTENTS
Page PREFACE
TASK 7 . FINAL REPORT Executive Summary ...... 1 Chromium Recovery Process Description ...... 3
TASKS 1.2. and 3 Introduction ...... 1-1 TASK 1 . Survey of Plating Wastes. MRS: Quantities. Compositions ...... 1-3 TASK 2 . Survey of Chromium Users and Purity Requirements ...... 1-5 TASK 3 . Review of Literature ...... 1-8 References ...... 1-12
TASK 4 . SOLVENT EXTRACTION SHAKER TESTS Introduction ...... 4-1 Test Procedure ...... 4-3 Results and Conclusions ...... 4-4 References ...... 4-5 TASK 4A . OPTIMIZATION OF SOLVENT EXTRACTION CONDITIONS AND CONCENTRATION OF REFINED SOLUTIONS Introduction ...... 4A-1 Test Procedure ...... 4A-2 Results ...... 4A-4 Conclusions & Recommendations for Future Work ...... 4A-7 References ...... 4A-8 TASK 6 . ESTIMATION OF PROCESS ECONOMICS FOR RECOVERY OF SALEABLE CHROMIUM PRODUCT Introduction ...... 6-1 Test Results for Extension of Work Begun in Task 4A ...... 6-2 Discussion of Results with Respect to Process Economics ...... 6-3 References ...... 6-4
Appendix A Appendix B Appendix C Appendix D .Proposed Change in Scope of Project: Task 5 change Appendix E .Estimate of Capital Costs a
Progress Report
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Metro Recovery Systems (MRS) 2430 Rose Place Roseville, MN 55113
Minnesota Office of Waste Management Industrial Waste Reduction Grant Program
REDUCTION OF CHROMIUM PLATING WASTES Task 7
Final Report
Michael Wismer Technical Manager, MRS and Malcolm T. Hepworth Consultant
November 1990 PREFACE
To the reader, this report is divided into several tasks which were set up in the original work contract. The first section of this report is Task 7, the final report with executive summary. It gives a brief description of the chromium recovery process which is illustrated by a block flow diagram. The report explores a recovery method using solvent extraction:- a process whereby an organic phase is contacted in multiple contacts with the aqueous (water) phase which contains waste chromium plus other metallic species which occur in the plating wastes. The organic phase is practically insoluble in the aqueous phase, and vice-versa, so that only metal ions are transferred between each phase. By controlling the pH (acidity) of the aqueous phase, it is possible to transfer (extract) all metals except chromium from the aqueous to the organic phase by a process termed "loading" the organic. The purified aqueous stream (raffinate) contained the purified chromium salt. Tasks 1,2, and 3 follow in the report and cover surveying of the plating wastes which were collected over a time interval at the beginning of the project. These wastes were collected from local plating companies and are processed by Metro Recovery Systems (MRS) to recover and recycle some metallic species, but not chromium. Presently, MRS must precipitate the chromium as a sludge and subject it to land-filling. In Task 2 a survey was conducted of chromium users to determine if there was a market for a purified chromium product and to determined the purity requirements. Task 3 is a review of the literature to determine whether or not the technology which was to be explored was unique and appropriate to the process. Task 4 reports on solvent extraction testing on a bench scale (shaker tests) to determine the conditions most favorable for producing a purified chromium product from the aqueous stream. In the original test plan, a high temperature (pyrometallurgical) process (Task 5) was also to be explored for recovering chromium; however, this alternative was abandoned for several reasons, primarily because it would not be possible to conduct such a process in the MRS facilities in Roseville. Instead Task 4A was agreed upon between the contractor and sponsor as a series of tests to optimize the solvent extraction process and to concentrate the refined solutions to produce a product. Task 6 is an estimation of the process economics for the recovery of a saleable chromium product. As this section details, the process is not economic at this time because of the dilute nature of the solutions which MRS is currently receiving from its clients. The primary unit of concentration used in this report is grams of metal species per liter of solution. For example 1gram per liter (gpl) represents a concentration of 1000 parts per million (ppm). Additionally the unit mg/liter is used, which is identical with parts per million. Some of the terms used in the description of the organic phase may be unfamiliar to most readers. The organic is primarily D2EHPA (di-2-ethylhexylphosphoric acid) which contains an additive DMOO (3,7-dimethyloctanol). In order for these two organic constituents to function properly, they are dissolved in kerosene (actually ESCAID, a Shell brand aliphatic diluent). For the purposes, therefore, of the average reader, the organic phase can be considered a kerosene-like material containing specific additives, which is essentially insoluble in water.
.-. EXECUTIVE SUMMARY
Metro Recovery Systems ,(AIRS) of Roseville, MN receives chromium plating wastes from electroplating and etching solutions as part of its processing operations. The chromium is reduced from the hexavalent state to a non-hazardous trivalent state via treatment with a chemical reductant, sulfur dioxide. The resulting solutions contain chromium in solution with several other plating residues, notably iron, nickel, copper, zinc, and cadmium.. Recovery methods for the latter four constituents of potential value are in place at MRS, and iron represents a valueless constituent. However, the separation of the above elements, especially iron from trivalent chromium solutions is not readily achieved by any commercial method.
Because of the hazardous nature of hexavalent plating solutions, platers are beginning to attempt to redirect their operations to trivalent chromium, but at this time, the bright plating finishes characterized by plating from hexavalent solutions is not readily achievable from the trivalent solutions. Therefore there is a potential but not current market for trivalent chromium solutions in the plating industry; however, the solutions must be pure and free from contaminants. There is a lesser market for trivalent chromium solutions in the tanning industry; however, iron in particular, is an impurity which must be kept at very low levels.
This study reports on a method of achieving the purification of trivalent chromium solutions and their concentration to a salt of chromium which could be saleable especially . to tanners. The method of purification is via solvent extraction in which the aqueous stream is contacted with an organic stream which removes all heavy metal cations except chromium. The aqueous stream is then treated with caustic additions to produce a precipitated salt which can be separated from the filtrate. This residual salt assayed 34.9% chromium, 10.6% sodium, 6.0% carbon, 6.7% sulfur, less than 100 parts per million (ppm) copper, 37ppm cadmium, less than 50 ppm iron, less than 200 ppm nickel and less than 50 ppm zinc. This salt contains residues of the organic phase and co-precipitated sodium sulfate. With further processing, such as removal of the organic via treatment with activated carbon and further washing to remove sodium sulfate, this salt would meet many of the requirements of tanners and may be saleable to potential customers. Further work is required to firm up this question.
As will be documented subsequently, this study was divided into seven tasks. One of these was an analysis of the streams received by MRS from its clients. Early projections upon which this study was based indicated that the received solutions would contain approximately 21,000 pounds of chromium per month; however, assays on chromium solutions over the period September, 1989 through July, 1990 indicated a monthly average of a little over 800 pounds of chromium per month. This difference in quantity has a significant negative impact on the process economics.
Several factors account for this shortfall in the amount of chromium received at the MRS facility. When this project was first proposed to the Office of Waste Management, MRS had been in operation only for three months with a limited client base. Data on the
1 potential amount of chromium available in the region was taken from a 1985-86 market survey study done for the MRS partnership. This study concluded that 250,000 pounds of chromium per year of chromium-containing process wastes were available in the MRS market area. Since this study, processing changes driven by waste minimization have reduced the amount of chromium in the market place. Notably, concentrated chromium enchants have been phased out at a number of companies because of their toxic nature and chromating baths utilizing lower chromium concentrations have been adopted. In addition, companies using chromium-based processes have installed in-house treatment equipment to deal with their own wastes. A final factor contributing to the level of chromium received at the MRS facility is market penetration. Although MRS has been in operation for two years with an expanding client base, the market place is competitive; therefore, MRS does not receive all the chromium available in the area. These and other factors will continue to affect the potential for chromium recovery technology.
In summary: A process has been developed for purification of chromium plating wastes and the concentration of the resulting purified solutions to produce a product which may be acceptable to tanners and also platers who use trivalent chromium solutions. This product may still require further purification to remove coprecipitated sodium sulfate and carbon which originated from the organic phase used in the solvent extraction process. Although the process is technically feasible, the process economics are not favorable to pursue this process until the level of chromium significantly exceeds the received levels by at least an order of magnitude. Independent break-even calculations by the authors have shown that the chromium concentration must”be 10 grams per liter in order to cover processing costs, and therefore, would need to be higher to repay the capital investment. Currently, wastes received average 2 grams per liter.
2 CHROMIUM RECOVERY PROCESS DESCRIPTION
Incoming aqueous wastes containing chromium and other metallic impurities are pumped to the equalization/feed tank (1). The chromium waste is pumped through a pH adjustment module (2) to adjust pH to 2.5, then it enters the counter current solvent extractor (3) where the aqueous phase continuously contacts the extraction solvent. Metal- loaded solvent phase exits the extractor and is mixed with acid in the acid mix tank (4) to strip metallic impurities free of chromium from the solvent phase. The aqueous/solvent phase separation tank (5) allows the metal stripped solvent to be returned to the solvent feed tank (6). Aqueous underflow from the phase separation tank (5) contains all metals except chromium and is sent to the existing metal precipitation system for treatment. Solvent losses and reagent adjustments are made by adding fresh extraction solvent from the solvent makeup tank (7) to the solvent feed tank (6).
The aqueous phase exiting the counter-current solvent extractor (3) has had metallic impurities removed to low levels leaving behind a solution composed largely of chromium (111) sulfate. This stream is directed to the recovered chromium equalization tank (8) from which it is pumped, batchwise, to the chromium precipitation tank (9). Sodium hydroxide is added to the recovered aqueous stream to form insoluble chromium (111) hydroxide, Cr (OH),. The Cr(OH), slurry is discharged into the recovered chromium solids settler/thickener (10) where the solids age and become more dense. Clarified liquid from this tank is decanted to the existing effluent treatment system. Underflow from the solids settler/thickener (10) is pumped through a membrane filter press (11) where solids are separated from the filtrate. Filtrate from the press is directed to the existing effluent treatment system.
The filter cake in the membrane press (11) consists of water, Cr(OH),, and a considerable amount of .sodium sulfate salt formed during precipitation. Fresh water is pumped into the press to wash the salt from the Cr(OH), cake. Filter cake may then be discharged and packaged for shipment to the recycler of the recovered product.
3 To existlng Metallic Waste TreatmenC
TO exiscine Effluent 1 Treatment Syscem
? Equalization/Feed Tank .
pH Adjustment Module
Counter-Current Solvent Extractor
Solvent Phase Acid Mix Tank
Aqueous/Solvent Phase Separation Tank
Solvent Feed Tank
Solvent Make-up Tank
Recovered Chromium Equalization Tank
Chromium Precipitation Tank
Recovered Chromium Solids Setttler/Thickener
(11) Membrane Filter Press
4 . Progress Report
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Metro Recovery Systems (MRS) 2430 Rose Place Roseville, MN 55113
Minnesota Office of Waste Management Industrial Waste Reduction Grant Program REDUCTION OF CHROMIUM PLATING WASTES Tasks 1,2, and 3
Michael Wismer Technical Manager, MRS and Malcolm T. Hepworth Consultant
September 22, 1989 INTRODUCTION The recovery of chromium as a recyclable product from electropIating and etching waste streams as collected by Metro Recovery Systems, Roseville, MN is the objective of this program. Currently, separation of chromium from mixed iron, nickel, zinc and copper solutions and hydroxide sludges is a difficult problem. Unless a separation or refining operation is undertaken these streams require disposal as chemically fixed solids; however, there are alternative approaches to produce either recjc!able or saleable products. Two of these approaches which were .proposed for examination are: solvent extraction to effect a separation between chromium, iron, zinc, nickel and copper; and carbon reduction on the hydroxide sludges to produce a ferro chromium product. If successful, there exists the potential to recover approximately 250,000 pouods of chromium per year from this one operation .- (MRS, Inc.). In this fist reporting period three tasks are addressed: Task 1 is a survey of the range of compositions and quantities of each major constituent of plating wastes received by MRS from its clients. This task is to be undertaken by studying past incoming material analyses and performing new analyses as required to provide accurate information.
Task 2 is a survey of chromium users to determine the degree of purity and valence state which would be required for the purchase of recovered and semi-refined material.
1-1 Tack 3 is a review of related research already reported in the area of hydrometallurgical and pyrometallurgical recovery of metals from mixed metal wastes with special emphasis on work undertaken by the Department of Metallurgy and Mineral Processing Engineering at the Montana College of Mineral Science and Technology in Butte, Montana, funded by the U. S. EPA
Task 4 is the planning and execution of laboratory shaker tests on typical solutions which hme been identified in Task 1 to determine the optimum pH, concentrations of solvents and solutes, temperature and organic-to-liquid ratios for hydrometallurgical sep;iration and recovery of the chromium from mived metal sludges and solutions. Metal concentrations and mass balances are to be reported among aqueous and organic phases between the aqueous feed, the loaded organic solvent and the raffinate. -
Task 5 will be undertaken if the solvent extraction tests appear inconclusive and will include tests on the pyrometallurgical recovery of ferrochromium product from chrome oxide/iron oxide plating sludges. This task includes determination of the optimum furnace conditions, quantities and type of reducing agent and also purge gas rate and crucible material to produce a saleabIe product.
1-2 Task 6 is to be a comparison of approaches for the optimum recovery of chromium consistent with MXS feedstock. In this task recomgendations will be made for the preliminary design of a pilot scale test system for further research, if warranted, or alternatively to provide preliminary design inforination for full scale operation. Rough estimates of capital and operating costs as well as revecues will be provided for a full scale operating system.
Finally in Task 7 a final report will be issued on this work. In this first reporting period, Tasks 1Gough 3 are covered. TASK 1 Survev of Platins Wastes. MRS: Ouantities. ComDositioa
During the period 4/20/89 to 6/6/89 the incoming bulk chrodun plating solutions to Metro Recovery System, Inc. were analyzed for the primary metaUic constituents of chromium, copper, zinc, iron, nickel, and cadmium. Each shipment of solutions was reported & terms of the gallonage and is reported in Table 1 below. From this table it is seen that concentrations of the constituents varies over a wide range from chromium solutions as concentrated as 11 percent (111,400 mglliter) to values as low as 180 mghter.
1-3 TABLE 1 Survey of Plating Compositions Received by MRS Spring, 1989 Date Received Concentration of Bulk Chromate Solutions
Assays: mg/liter , Gallons Date Received Cu Ni Zn Cd Fe Cr Gallons 4-21-59 386 6.4 790 80 100 860 2000 4-20-59 1.9 21 470 2.7 3450 64500 480 4-20-59 2 1400 8.0 34 1.7 23 23600 220 4-25-59 35 17 390 11 4.7 465 1000 4-18-59 46 3.7 550 222 33 1250 3000 4-26-89 15 3.2 600 15 56 960 2000 4-28-89 375 4.0 745 ’. 0.3 63 670 1000 4-25-59 392 11.2 690 22 - 70 450 2000 5-2-59 2.8 0.28 500 0.44 6.9 150 2000 5-3-89 71 4.2 15 0.06 40.7 398 1000 5-3-89 1.95 1.6 0.48 10.64 353 1000 5-4-89 65 1140 94 220 1000 2000 5-4-89 11.8 5.9 400 22 24 310 3000 5-5-89 10.4 2.0 740 , 0.2 80 490 2000 5-5-89 1200 450 360 ’ 18 160 5600 1600 5-5-89 615 0.43 0.083 34.85 277 3000 5-9-89 113 11.2 0.7 16.6 11,158 1000 5-9-89 2.7 2.1 117 2.6 70.3 6875 2700 5-10-89 1104 1.8 627 1.7 52.4 432 2000 5-11-89 3.2 0.3 1200 0.09 81 340 1350 5-11-89 353 580 1250 . 94 68 2410 2000 5-12-89 0.5 0.6 445 0.15 26 974 1000 5-15-89 185 6.9 430 05 14 380 3000 5-19-89 2.05 ,847 1730 29 643 1937 3000 5-19-89 110 103 3700 137 700 2100 3000 5-22-89 1.4 0.2 470 032 6.9 270 1950 5-17-89 15 0.2 166 0.03 2.1 640 275 5-24-89 0.6 0.3 1500 a 0.08 28 1260 250 5-25-8 9 183 8.53 649 68.9 41.93 3532 1000 5-25-89 3.72 .154 1067 .053 22.50 571 1580 5-26-89 3625 28.06 1086 61.7 . 96.8 788 2000 5-30-89 83 13 858 29 29 2341 3000 5-30-89 30 28 724 10 42 4000 5-31-89 28220 12 41 22 11.6 111400 275 6-5-89 1.1 .6 1140 .44 88 180 1000 6-5-89 179 6 16 405 486 760 3200 2000 6-5-89 79 113 2450 6.1 29 2780 2000 6-6-89 -15 2.0 51 1.5 10260 3183
1-4 The bulk of the volume of chromium waste solutions has, typically, chromium levels of about 1 gram per her. These solutions are primarily in the sulfate form with some containing nitrate, chloride and fluoride. A composite anion composition will be reported in the next quarterly report. For the present, it is assumed.that the system is primarily sulfate in origin. There exists at iWS, methods of recovery of copper and nickel from solutions; however, at present chromium, after being reduced by sulfur dioxide to the trivalent state, is currently being precipitated as a sludge. The main thrust of this present investigation is to separate chromium from the other metallic species, in particular iron, ahd to concentrate the chromium solutions to a level where they can be recycled to plating or other operations.
TASK 2 Survev of Chromium Users
In Task 2, companies who are potential purchasers of the chromium solutions were surveyed to determine the degree of purity they require and also the approximate quantities which they would be willing to consider purchasing should market conditions be favorable. The survey was sent to two groups of potential clients: The first group were suppliers of chromium chemicals to the plating industry, and the second were suppliers to the tanning industry. The questionnaire sent to both groups and an example of the two cover letters is included as Appendix A, Exhibits 1 and 2, and the Questionnaire (Exhibit 3). The reason for extending the survey to include this second group (tanners) that initial responses from the suppliers of plating chemicals
1-5 indicated that by far the major demand in the pIating industry was for hexavalent chromium rather than trivalent sulfate solutions. Some trivalent chromium is used in decorative finishing; however, bright-finished chromium products, which comprise the majority of plated materials continue to require the use of.the hexavalent form. One major supplier of hexavalent chromium chemicals to the plating industry is McGean-Rohco, Inc of Cleveland, Ohio. Their representative, iMr. Gary C. Clark, Vice President of the McGean Division responded to our questionnaire that they would be pleased to receive a minimum of 200,000 pounds per year of chromic acid (solution or solid form) at a punty of 98% at a price ranging from $25 to $.75 per pound of contained solid chromic acid. Some penalty might be assessed for certain unspecified trace elements (presumably iron). A major user of trivalent chromium'sulfate is the tdgindustry. One local user the S. B. Foot Tanning Company of Red Wing, would be pleased to accept a minimum volume of 200,000 pounds per year of trivalent chromium as a sulfate chemical; however, it would have to be "iron free". They would be interested in paying approximately 50 cents per pound of contained-chromium. (The basis is assumed to be chromium; however there is some ambiguity that the basis might be Cr2O3.) They express interest in receiving the chromium in a 15 percent by weight aqueous solution as a chromic sulfate. A supplier of chromium chemicals to the tanning industry, the Wayne Chemical Corporation of the Harcros Chemical Group (Milwaukee Wisconsh), answered our questionnaire in detail (see Exhibit A Exhibit 4). A taming company, Blackhawk Tanning Co of iWwaukee, Wisconsin, also indicated an interest in trivalent chromium but stipulated that it should be "iron free"
1-6 (presumably 5Oppa mair" iron content See: Haraos specifications in Appendiv A). Another tanning company, Radel Leather Company responded with an ambiguous reply that they were interested in "chromic trivalent) sulfate, Cr203". .Agah they e.upressed the requirement that the product be low in iron. The Hablet & Hayes Company of Salem, Massachuettes responded that they produce lower valent chromium sulfate by reduction of sodium bichromate with g!ucose. Tfieir starting reagent is a technical grade liquor assaying 69 to 70 percent Na2Cr207 2H20. The minimum volume on an annual basis they would consider purchasing is 400, on pounds at 15a: per pound. (See appendix A e'xhibit 5 for specifications on the sodium bichromate starting reagent. This information encouraged us to continue our efforts in the direction of avoiding reoxidation of the already reduced- chromium solutions, and thereby avoiding rehandling a potentially carcinogenic chemical. A total of 58 companies producing chromium chemicals were sent surveys. Replies are still being received at the time of Writing this report. A final result of this survey will be included in the next reporting period. A Total of 245 tamers were surveyed. The responses to this questionnaire at this time of writing are also in the process of being received and cataloged. The most si,onificant response with respect to a potential outlet for MRS-produced chromic sulfate occurred in a telephone conversation between M. T. Hepworth and Mr. Ernest Hagen, Technical Director of the S. B. Foot Tanning Company of Red Wing is summarized below: Summaw of teIeDhone conversation of 7/24/89: "I spoke with Mr. Hagen of S. B. Foot Tanning Co. He stated
1-7 he estimated their company could utilize up to 700,000 pounds per year of Cr20; contained in aqueous solution as a 15% by weight solution. This soIution would be chromic sulfate; the designation Cr203 does not refer to valence state but to chromium units. He indicated that in Europe, tanners use a spray-dried powder; however, in this country they use the aqueous form. This solution currently markets at 26 cents per pound or $1.73 per pound of contained Cr2O3. They can tolerate a limited quantity of impurities such as AI, Ti, Zn: Xi, Cu; however, he emphasized that Fe is a particulariy deleterious impurity. He was Specific that their Texas tannery used 180,000 and their St. Paul tannery used 120,000 pounds per year of Cr203 equivaient. Another local tanning company, Uber Tannins Co of Owatonna, MN
.) continues to use hexavalent chromium;zhowever, the trend is away from hexavalent chromiUm use.
TASK 3 Review of Literature
The problem of separation of chromium and its recovery from plating sludges and solutions has been addressed by a number of studies. Most recently by Twidwell and Dahnkel in a study sponsored by the U, S.. EPA. Their approach was to solubilize chromium-bearhg solutions and to accomplish the separation of iron from chromium by phosphate precipitation. This approach is utilized to remove trivalent metal ions from divalent metal ions. It enables Al( +3) and Cr( +3) to be selectively precipitated from Zn( +2), Ni( +2)
1-8 and other divalent ions. Also the precipitation kinetics of iron and chromium are claimed to be sufficiently different because of an incubation period in chromium phosphate precipitation that it remains in solution; whereas, iron is precipitated quantitatively prior to chromium precipitation. By elevating the temperature to above 50°C, chromium is made to precipitate leaving the other divalent metal ions in solution. It is then necessary to convert the chromium phosphate which is produced to hexavalent chromic acid via a soda ash roast process in another unit operation at elevated temperature. This is done by fusion with sodium carbonate for one hour at 720°C foIlowed by crushins and water leaching to produce a water-soluble hexavdent chromium aqueous solution. The flowsheet developed by Twidwell and Dahnke has been thoroughly studied and appears to be on sound technical ground. However, there is reluctance to include additional high temperature unit operations in our local waste treatment facility to reoxidize chromium which has been previously reduced to the trivalent state (by reduction with sulfur dioxide) to produce hexavalent chromium which is on the EPA list of hazardous chemicals.
In OUT survey we specifically inquired whether there was a market for trivalent chromium solutions. We found that a local supplier of tannhg chemicals was interested in receiving 15 percent solutions of trivalent chromium sulfate. Consequently our attention has been directed to maintaining the chromium in the trivalent state and to separate it from the other species by solvent extraction using a combination of D2EHPA (di-Zethylhexyl phosphoric acid) with DEMO0 (3, 7-dimethyloctanol oxime) as a synergistic additive to assist in organic extraction of nickel, zinc, copper and cadmium, leaving the chromium
1-9 in solution. In another study on waste electroplating liquors by Davey et a12, ion- exchange on cross-linked casein was used to recover hexavalent chromium selectively from waste plating solutions. Solutions from which the anionic species Cr(+6) was szlectively absorbed were passed through a column containing the cszin while the cationic species Cr(t3), Zn(i2), and Cd(+2) passed through. The chromium( + 6) was eluted with ammonia. The presence of iron as a contaminant is not discussed. Rydberg et 31.j repor1 on the use of TBP (Tributjl phosphate) in kerosene in a solvent extraction process where chromium is complexed primarily with fluo~de. Since the LMRS system is mainly a sulfate system, it does not appear that this approach will be suitable. When chromic acid is used as an etchant, a system described by A. R. Boyce of Tektronk and D. J. Kavanaugh of CH2M Hill4 has merit. This system is suitable at the facility where the etching is done via reoxidation of chromic acid within an electrolytic side cell. However, if the solution is contaminated with other metal ions and diluted, this approach has not the same viability. The Eco-Tec? system uses a combination of cationand anion exchangers for chromim recovery and is applicable, again to systems where little cross-contamination has occurred. Soboroff et a16 of the U. S. Bureau of Mines have reported on the operation of a diaphragm cell for electrolytic oxidation of trivalent chromium with simultaneous removal of copper and zinc ions. This system appears viable and is again best utilized within the operations of an etching and pIating shop, but not appropriate for a mixed plating system where high degrees of dilution have occurred rendering electrolysis a highly inefficient process. The Ecru7 system is another version
'1-10 of a one which oxidizes trivalent chromium to hexavalent and has similar limitations for implementation at MRS. Hepworth8 in a study for the U. S. Army Toxic and Hazardous Materials Agency studied the behavior of a hydroxide and ,oypsum sludges
originating from a composite of U. S. Army plating sludges. The solution compositions he encountered were in the range of compositions of solutions received by MRS and were amenabk to a range of treatments including sulfide precipitation for the removal of copper, zinc and some nickel from solution. Iron wss not quantitatively precipitated, and chromium was lek in solution since it does not form a stable sulfide. In a subsequent operation to effect separation of divalent iron and nickel from chromium, solvent extraction was attempted in some preIiminary tests. The organic phase consisted of D2EPHA with DMOO added as a synergist in an aliphatic dihent. These preliminary .: .: . tests served as the basis of the proposd’ts undertake this present program. Test work on solvent extraction studies will be reported in the next Task
..
1-1 1 REFERENCES
1. Twidwell, L. G. and Dahnke, D. R.: Metal Value Recoverv from Metal Hvdroxide Sludses: Removal of Iron and Recove? of Chromium, EPA Report CR-812533-01-0, December 1957, Montana College of Mineral Science and Technology. 2. Davey, Peter T., Houchin, Martin R., and Winter, George: "Recovery of Chromium from Waste Electroplating Liquors by Ion-Exchange on Casein. Part 1. Pilot Plant Studies", J. Chem. Tech. Biotechnol. 33.4, (1983), pps.164-170. 3. Rydberg, J., Reinhardt, H, Lunden, B. and Haglund, P.: "Recovery of Metals and Acids from Stainless Steel Pickling Bath," Evans, David J. I. ED: Organization of the Second International Hydrometallurgy S,mposium, The American Institute of Mining, Metallurgical, and Petroleum En,oineers, Inc. .z . I Baltimore, MD (1973) pps. 589-611. 4. Boyce, A R. and Kavanaugh, D. J. :"Electrolytic Regeneration of Chromic/Sulfuric Acid Etchant," Conference on Environmental Control for the Metal Finishing Industm, American Electroplaters and Surface Refinishers Society, Orlando, Florida 1/88 as reported in The Hazardous Waste Consultant May/June 1988 pps 1-23 tp 1-23. 5. ECO-TEC, Ltd.: "Chromic Acid Recovery System", ECO-TEC, LTd. Product Bulletin (925 Brock Rd. S., Pickering, Ontario, Canada. 6. Soboroff, D. M., Troyer, J. D., and Cochran, A. A. Regeneration and Recycling of Waste Chromic Acid-Sulfuric Acid Leachants, U. S. Bureau of Mines Report of Investigations 8377, (1979). 7. "ECRU System for Regeneration Chromic Acid Regeneration Converts Trivalent Chrome to Hexavalent" : Product Catalog.
1-12 8. Hepworth. M. T.: Plating Sludse Metal Recovery Report AMXTH-TE-TR- 85015 Final Technical Report for U. S. Army Toxic and Hazardous Materials Agency, Aberdeen Proving Ground, MN on Contract 7DM11-84-C-0045 May 30, 1985.
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7 Progress Report
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Metro Recovery Systems Attn: W. Michael Wismer Technical Manager 2430 Rose Place Roseville, MN 55113
Minnesota Office of Waste Management Industrial Waste Reduction Grant .Program
REDUCTION OF CHROMIUM PIATDTG WASTES Task 4 Solvent Extraction SEaker Tests
Malcolm T. Hepworth Principal Investigator
February 1, 1990 INTRODUCTION
The prior progress report on this project, dated September 22, 1989, covered three Tasks:
Task 1: A survey of the range of compositions and quantities of each major constituent of plating wastes received by Metro Recovery Systems (MRS) from its clients.
Task 2: A survey of chromium users to determine the degree of purity and valence state which would be required for the sale of recovered and semi-refined material from MRS.
Task 3: A review of related research already reported in the area of hydrometallurgical and pyrometallurgical recovery of metals from mixed metal wastes.
This present report addresses Task 4.
In Task 4, the following effort has been agreed upon in the contract between MRS and Minnesota Office of Waste Management:
"the pianning and execution'of laboratory shaker tests is undertaken . on typical solutions which have been identified in Task 1 to determine the optimum pH, concentrations of solver& and solutes, temperatures and organic-to-liquid ratios for hydrometallurgical separation and recovery of the chromium from mixed metal sludges and solutions. Metal concentrations and mass balances are reported among aqueous and organic phases between the aqueous feed, the loaded organic solvent and the raffinate."
In the prior report, in Task 3, plating solutions which had been received by MRS for processing were assayed over a period of six weeks. A typical solution from ths composite was assayed and contained the following constituents:
Chromium 2007 ppm Nickel 221 ppm Iron 140 ppm Copper 445 ppm Cadmium 49 PPm Zinc 508 ppm.
The constituents were present primarily in sulfate solution at an excess acidity of approximately 37 grams of sulfuric acid per liter of solution for a pH of 0.4. Upon titration of this solution with 5N NaOH, the onset of precipitation was observed to occur aftei the addition of 150 ml/liter of starting solution. This preliminary test indicated that this starting solution had acid as its primary constituent. This high degree of acidity may be a result of prior overdosage
4- 1 with sulfur dioxide in order to assure reduction of the contained chromium to the trivalent state.
This solution, which had been determined to be typical of plating wastes processed by MRS, served as the starting point for solvent extraction testing reported in Task 4. The objective of this testing was the separation of nickel, iron, copper, cadmium, and zinc from chromium in order to produce purified solutions containing only chromium which would be suitable for marketing to companies identified in the prior survey. The nickel, copper, cadmium, and zinc species, which are extracted in the organic phase would subsequently be stripped into a separate aqueous solution to be treated in-house at MRS in future studies, The purpose of this present study is,limited to an examination of the chromium-rich aqueous stream after contact with. the organic stream.
A schematic diagram of the separation system is presented in Figure 1 which shows the proposed distribution of metal species in the several streams. Task 4 is devoted to the SX loading circuit’Xo remove the heavy metal constituents shown to produce a purified chromium solution. .
As was described in the original proposal, chromium is not readily extracted by the organic system chosen for this study at the pH regime selected. Hence it remains essentially at the initial concentration it had in the as-received stream; however, minor dilution occurred as a resGt of the addition of base for pH adjustment. In order to produce a marketable chromium stream, a concentration step would be required. This concentration step would follow the purification step and is illustrated in Figure 2. In this figure, three possible downstream concentration steps are considered for the purified chromium stream:
a) Concentration by evaporation to bring the chromium levels up to a point where shipping costs do not overwhelm the cost evaluation of the chromium for reuse by a secondary market. b) Loading on ion exchange media in a manner similar to the way in which the mixed plating wastes were received by MRS from its clients. By proper choice of loading and stripping conditions a more highly-concentrated stream of chromium can be obtained than the purified feed solution. c) Precipitation of chromium from the purified chromium stream by addition of ammonia or caustic. Ammonia may be the reagent of choice if provision is made to recover and recycle it via a lime-boil step in which lime (a low-cost reagent) is added to the filtrate from the chromium precipitation step.
In the next section of this report, progress in reported on Task 4: the SoIvent Extraction Shaker Tests for the purification of the chromium solutions.
4-2 TASK 4: Solvent Extraction Shaker Tests
In the Task, the effects of multiple contacts between the starter aqueous feed solution and an organic phase is undertaken. The organic phase is a solution of 20 percent by weight DMOO (3,7-dimethyloctanol oxime), 10 percent by weight D2EHPA (di-2-ethylhexylphosphoric acid) and 70 percent by weight ESCAID (a commercial name for Shell brand aliphatic diluent which is commonly known as kerosene). *
Two of these three reagents, D2EPHA and the diluent are readily available through competitive commercial suppliers; however, DMOO must be prepared by a relatively simple synthesis, described in Appendix B of this report.
TEST PROCEDURE
In order to clarify the terms used in this procedure a brief explanation is given below:
The term "shaker tests" is used to describe the generic procedure for contacting aqueous and organic phases in a separatory flask equipped with a stopper and a drain cock to separate the more dense aqueous phase from the less dense organic phase. In our test procedure a more reproducible method was used to determine the maximum degree of separation at equilibrium. This equilibrium distribution of a species between the organic and aqueous phases is referred to as an "isotherm". The purpose of the shaker tests described below is to determine the optimum value of pH in the aqueous phase and the optimum number of contacts required to effect a separation between chromium, which is not readily extracted into the organic phase, and the other extractable heavy metal constituents of iron, nickel, copper, cadmium, and zinc.
The contacts between organic and aqueous phases were made in a 400 ml indented beaker with stirring by a slotted disk impeller. The beaker dimensions were 7 cm in diameter and 10 cm in height. The four indentions at 900 apart were 1 cm in depth. They acted as baffles to increase mixing. The impeller was 4 cm in diameter and 0.5 cm thick with three equally spaced radial slots. The mixer maintained a rotational rate of 300 rpm. A sketch of this laboratory reactor is shown in Figure 3.
The initial combined volumes of organic and aqueous phases were maintained at 200 ml. The adjustment of pH was accomplished by addition of 10N NaOH. Ten milliliter samples were removed from the mixed solution (impeller on) with a disposable syringe. This mixture then separated into its two phases, allowing for subsequent analysis of both organic and aqueous phases; however, except for spot checks, the aqueous phase was used primarily for securing mass balances.
4-3 The degree of agitation was sufficient to secure equilibrium within the ten minutes of contact time allowed before sampling. Ritcey and Ashbrook* report that the kinetics of extraction for all species except chromium is practically instantaneous upon contact with D2EHPA. The very slow extraction kinetics of chromium are reported by Lo, Baird and Hamon: The addition of DMOO is not expected to change the contact kinetics si,gificantly.
All measurements of pH were taken while mixing. The pH electrode was calibrated before and after each measurement with a standard pH 1.00 buffer. All contacts were made at ambient temperature (25°C). The organic solvent is a solution of 10% D2EPHA, 20% DMOO and 70% ESCND. The aqueous solution was always taken from the same carboy of plating waste as received from MRS of the assay reported earlier. In reporting on Task 4 the aqueous-to-organic volumetric phase ratio was maintained at 1 to 1; however, other phase ratios will be reported in the next report. Two sets of data are reported here. They are termed: "Same Aqueous, iMultiple Organic" (SAMO) and "Same Organic, Multiple Aqueous" (SOMA). In the SAiiO series of tests, the aqueous solution is contacted with fresh, unloaded organic phase in up to 4 contacts with cumulatively greater quantities of the heavy metal ions being transferred from the aqueous with each contact. In the SOiMA series of tests the situation is the converse with cumulatively greater loading of the organic phase by exposure to fresh aqueous in each contact.
RESULTS AND CONCLUSIONS Table 1 and 2 summarize the results of the SAMO tests from the aqueous phase labeled "Initial Concentration". The levels of each of the heavy metal constituents, Cr, Ni, Fe, Cu, Zn are given in parts per million by weight in Table 1. In Table 2, the percent extraction for each element is given. The table shows four contacts each for three pH values, 1.5, 2.0, and 2.5, respectively. For the range of pH values examined, extraction of chromium, even though it is the majority species, is low, as was expected. This is the case even for long contact times (ten minutes). For shorter contact times (for example 1 minute) the kinetic factor would be expected to lower, even further, the amount of chromium extracted since it is reported to have significantly slower transfer kinetics than the other elements? At a pH of 2.5, and four contacts, up to 8 percent of the chromium is transferred to the organic phase, where it could later be recovered by selective stripping. However, nearly complete removal of nickel and zinc occur with removals of iron, copper, and cadmium reported at 100% within analytical error.
The results SAMO tests are summarized in Figures 4 through 6 where the percent extraction is shown for the four contacts for each pH value.
Tables 3 and 4 summarize the results of the SOMA tests. In this series, the effect of multiple loading of the organic phase is shown: the first contact shows
4-4 the greatest separation, while each succeeding contact shows greater loading of the constituents which contaminate the chromium aqueous phase. Again the highest pH value studied (2.5) shows the best discrimination between chromium and the other metal species. If the pH had, however, been increased further, more chromium would have been loaded with the other heavy metals into the organic phase.
The results of the SOMA tests are summarized in Figures 7 through 9 where, again, percent extraction is shown for the four contacts for each pH value.
From these results it is concluded that the optimum pH is 2.5 and the optimum number of organic contacts is 4. The SAM0 contact gives best results, as is expected. It would be necessary in commercial practice to stage the contacts with recycle streams in order to make most effective utilization of the organic phase. The loading capacity of the organic decreases significantly after the initial contact; however, this problem could be avoided with continuous counter-current (aqueous vs. organic) contact. The purified chromium solution has a chromium concentration of 1.8 grams per liter with minimal impurities.
Attached as Appendix C is a letter to Mr. Michael Wismer in which a recommendation is made that Task 5 be replaced with Task 4A, a continuation of the hydrometallurgical study chromium separation and concentration.
REFERENCES
1. Ritcey, G.M. and Ashbrook, A.W., Solvent Extraction Principles and ADplications to Process Metallurm. Part 11, Elsevier Scientific Publishing Co., 1979.
2. Lo, T.C., Baird, M.H.I., and Hanson, C., Handbook of Solvent Extraction, John Wiley and Sons, 1983.
4 -5 Figure 1. Schematic Diagram Showing Distribution of Metal Species
Dilute Cr Solution - 2 g/l I I Precipitation
I I . -. I I .Cr Concentrate
Figure 2. Schematic Diagram Showing Possible Concentration Routes p
Figure 3. Laboratory Reactor
4-6 pH=L5, Same .Aq. Multiple Org. Phase Ratio = l/l 120 -- Cr + '0°-1-1:--80 Ni mY Fe / --5- -cu Cd
.) i I\ I I Zn I 2 3 4 Number OF Ccntccx
Figure 4. SoIvent Evtraction Loading Tests SAMO pH=2.0, Same Aq. Multiple Org. Phase Ratio = 1/1
120 -.
100t100 A. Ni 80 d - 60 Fe "/ _Ef_ 40 cu _jt_ Cd + 2ol0 1 2 3 4 Zn blumbef of Contacts
Figure 5. Solvent Extraction Tests SAMO
4-7
Progress Report
to
Metro Recovery Systems Attn: Mr. Michael Wismer Technical Manager 2430 Rose Place RoseviHe, MN 55 113
Minnesota Office of Waste Management Industrial Waste Reduction Grant Program
REDUCTION OF CHROMIUM PLATING WASTES
, Task4A 5 and Concentration of Refined Solutions
Malcolm T. Hepworth Principal Investigator . June 15,1990 INTRODUCITON
The prior progress report on this project, dated February 1, 1990 covered Task 4:
Task 4: In Task 4, the following effort was agreed upon in the contract between MRS and Minnesota Office of Waste Management:
"The planning and execution of laboratory shaker tests is undertaken on typical solutions which have been identified in Task 1 to determine the optimum pH, concentrations of solvents and solutes, temperatures and organic-to-liquid ratios for hydrometallurgical separation and recovery of the chromium from mixed metal sludges and solutions. Metal concentrations and mass balances are reported among aqueous and organic phases between the aqueous feed, the loaded organic solvent and the raffinate."
In the original contract, effort in Task 5 was to be directed towards pyrometallurgical recovery of a ferrochromium product from the representative plating solution which was identified in Test 3; however, on February 5, a request was made by letter for change in project scope (letter from Michael Wismer of MRS to Ms. Julie MacKenzie of the Minnesota Office of Waste Management included in this report as Appendix A). This request was subsequently verbally approved for a continuation of the work. The original Task 5 was to be replaced by Task 4A. Essentially the pyrometallurgical treatment described in Task 5 is impracticable. A better use of remaining funds on this program would be to improve the technological base for evaluating the hydrometallurgical purification and concentration method of treating the representative chromium-bearing waste stream by an extension of Task 4 to Task 4A.
TASK 4A: ODtimization of Solvent Extraction Conditions and Concentration Tests on Refined Solutions
In Task 4A conditions are to be determined for the solvent extraction and purification of chromium-bearing solutions to "ize metal impurities by examining the effect of varying organic-to-aqueous Ioading ratios. Also the loading kinetics of the impurity species from the aqueous to the organic phase are to be examined. Furthermore, methods of concentrating the purified aqueous chromium phase (raffiate) resulting from the extraction process would be examined. These concentration methods would include evaporation/crystallization, precipitation, and ion exchange.
4A- 1 TEST PROCEDURE
The tests which were performed are divided into two types: optimization of solvent extraction conditions and concentration tests on refined solutions.
Outimization of Extraction Conditions
Single Contact Tests
The test procedure described in Task 4 in the prior report was applied to starting solutions of an assay shown in the first row of Table 1. The organic phase was a solution of 10% D2EHPA (2-ethylhexyl phosphoric acid), 20/5 DMOO (dimethyl-octanal-oxime), and 70% ESCAID (trade name of a pure kerosene) aliphatic diluent. In the series reported in Table 1 a single contact was made between aqueous and organic phases for seven different phase ratios of Aqueous-to-Organic (Aq/Org) of lO/l, 5/1,2/1, 2/1,1/2,1/5, and 1/10, respectively. The pH was also varied by additions of ION NaOH solution to include the values 1.0, 1.5, 2.0, 2.5, and 3.0. Only the aqueous.phase was analyzed after contact. The total volume of the two phases before base additions and sampling were approximately 220 ml (e.g., for the 10/1 Ag/Org, 200 ml of aqueous plus 20 ml of organic phase were used.) The aqueous and organic phases were added to a 400 ml indented beaker equipped with a slotted disk impeller, aqueous first and then organic (aqueous continuous). The midng was begun and the initial pH recorded. Sampling was accomplished by remoying a 10 ml sample from the mixing solution (impeller on) with a disposable syringe. This mixture was then separated into two phases; thereby both phases are sampled while maintaining the initial phase ratio of Aq/Org. For each phase ratio, five samples were withdrawn every ten minutes after pH adjustment. Ten minutes of contact time was chosen as sufficient bases upon the reports of other investigators (Ritcey and Ashbrook') who have shown that the kinetics of extraction of all species except chromium are practically instantaneous. Since chromium is the species which is not being extracted, there is no difficulty in this respect. All pH measurement were taken while mixing with the electrode immersed in the mixture of organic and aqueous. The pH electrode was calibrated before and after each trial with the appropriate standard buffer and was within 0.05 pH units of the standard. An automatic temperature compensator was used on all pH measurements with contact made at 25OC (within +/-3"C.)
Multi~leContact Tests
In these tests, the same aqueous phase was contacted with fresh stripped organic in multiple organic contacts. (Same Aqueous, Multiple organic SAMO). A similar procedure was followed as the multiple contact tests; however, pH adjustment was made on every contact. Individual contact times were typically fifteen minutes.
4A- 2 Concentration Tests on Refined Solutions
The concentration tests on the refined solutions included three methods, evaporation followed by crystallization, precipitation, and ion exchange.
Evaporation and Crvstallization
Exactly 250 ml of purified chromium solution from the final raffinate from the multiple contact test was used in this test. The solution originated Erom the four contact tests in which the phase ratio was 1/1 and the pH was 2.5 (See Table 3). This solution was placed in a 400 ml beaker and evaporated in a steam-heated enclosure at 105°C overnight to dryness. The resuIting crystalline solid was analyzed for the following elements: Cr, CU, Cd, Fe, Ni, and Zn.
Precbitation
The same volume of the same solution as described above was subject to pH adjustment with 10 normal sodium hydroxide solution in a magnetically-stirred 400 d beaker. The pH was continuously monitored as base was added over a time interval of approximately five minutes. When the pH stabilized at a value of 10.1, the solution no longer was observed to undergo drifts in pH. The stirring was discontinued and the solids were allowed to settle. The temperature was maintained at 25°C during base addition. The supernatant solution was filtered and the solids were collected and dried as above. Both the filtrate and solids were analyzed for the above elements and masses and volumes recorded.
Ion Exchanpe
A volume of 250 ml of the same solution as above was contacted with 150 ml (wet basis) of cation exchange resin (IRC 120, produced by Rohm and Haas) which was obtained from MRS. The resin was preconditioned with 10% sulfuric acid to render it into the acid- chelated state. The railinate was contacted in a 400 ml beaker which w& magnetically- stirred overnight and maintained at room temperature. Subsequently, the solution was decanted and filtered from the beads and analyzed for the above-listed elements. The resin was contacted for three hours in a 400 ml magnetically-stirred beaker with 50 ml of 10% sulfuric acid solution as an eluate. The eluate was separated from the resin and analyzed for the above elements.
4A-3 RESULTS
The test results are summarized as follows:
Optimization of SX Conditions
Single Contact Tests
The results of the single contact tests are given in Tables 1 and 2. In Table 1, the starting concentrations are shown for a representative plating waste stream which was obtained as part of Task 1. The various series of Aqueous-to-Organic ratios are shown with the pH regimes for each contact.
In Table 2, these same data were expressed as percent extraction. These data are plotted in Figures 1 through 7 for the respective Aq/Org ratios. Note that Figure 1 (Aq/Org = 10/1) shows relatively low extraction, which is a result of the low loading capacity of the extractant at low pH values (<2). The exceptions are iron and copper which load readily under all conditions because of their strong chelating behavior. Figure 2 (Ag/Org = 5/1) shows more favorable extraction, especially of zinc and cadmium. Chromium continues to remain unextracted. In Figures 3, 4, 5, and 6 (respective Aq/Org = 2/1, 1/1, 1/2, and 1/5) one notes that chromium begins to extract at pH values greater than 2; however, the other metal impurities approach greater than 95% extraction efficiency. In Figure 7, the chromium extraction at all pH values is in the range of 18 to 20% because of the large amount of organic (low Aq/Org ratio). Also pH control is difficult at this phase ratio as evidenced by erratic values and therefore subject to error. The role of iron in all the figures is that the extractant preferentially loads iron. High iron concentrations in the aqueous stream will tend to crowd the other metals off the organic phase.
Returning to Table 1, the degree of purity of the chromium solution can be seen for the 1/1 at a pH of 2.5. Under these conditions, zinc is still a minor contaminant in the raffinate; however, this contamination can be removed by multiple contact of fresh organic with the aqueous. If one advances the pH to 3.0 under the 1/1 Aq/Org ratios, then it is seen that chromium is also extracted. Clearly economics dictate the not using the very low Aq/Org ratios where the organic inventory is higher. Optimum conditions for single contacts, therefore, appear to be in the pH range of 2.0 to 2.5 at an Aq/Org ratio ranging Gom 2/1 to 112.
Multiple Contact Tests
An aqueous phase ratio of 1/1 was chosen for these tests. The results are shown in Tables 3 and 4. In Table 3, the assays of the aqueous solutions are shown against pH values
4A-4 I.
for one, two, three, and four contacts, respectively. In Table 4, the results are expressed in percent extractions.
In figures 8, 9, and 10, the results show the percent extraction as a function of the number of contacts for each of the pH values. In Figure 8, one sees poor extraction for all of the metals except for iron, which is a result of the low loading capacity of the extractant at low pH values. This situation improves in Figure 9 for a pH of 2.0; however, in Figure 10, for four contacts, the extractions of all metals except chromium are greater than 99 percent. Note, however, that some chromium (8%) is extracted under these conditions, but this chromium can be forced back ,into the aqueous phase by counter-current operation.
Concentration Tests on Refined SoIutions
The results of the concentration tests on refined solutions is expressed below. All solutions which were subject to the concentration steps originated from the refined solution: (Four multiple contacts at a pH of 2.0, Aq/Org ratio 1/1 as described previously).
Evaporation and Crvstallization
Two hundred-fifty ml of purified solution was evaporated as 105°C for 12 hours and then further evaporated at 320°C for a few additional minutes. The additional heating was required because of the deIiquesent nature of the evaporated residue. The dried residue weighed 21.2 grams and consisted of a light green powder. The assay of this residue was:
2.1% Cr 8ppmCd . 12 ppm Cu 120 ppm Fe 150 ppm Ni 400 ppm Zn
These results indicate that the starting solution contained a large proportion of sodium sulfate, which is the primary contaminant.
Precipitation
Two hundred-fifty ml of purified solution was treated with 4.6 ml of 10 Normal sodium hydroxide to a final pH of 10.1. The precipitate was washed with deionized water * and dried at 105PC overnight. The final precipitate required no further drying and was sky blue in color. The analysis of this precipitate was:
4A- 5 14.5% Cr 37 ppm Cd 100 ppm Cu 380 ppm Fe 860 ppm Ni 2700 ppm Zn
Ion Exchanqe
Two hundred-fifty ml of purified solution was adjusted with 7 d of 5.0 normal sodium hydroxide to a pH of 4.1 and then contacted with 150 ml of wet conditioned (in the hydrogen state) IRC 120 resin for 15 hours in a stirred beaker. The resin was then filtered and contacted with 50 ml of 10% by volume sulfuric acid solution for a three hour strip time. The eluate was analyzed and had only 740 ppm chromium; whereas, the raffinate contained 996 ppm chromium. These results indicate that the loading of the resin is extremely slow and that concentration by this resin is impracticable.
In Summary
Concentration by precipitation and washing of the precipitate for the purified solution appears to be the only viable approach unless a resin of better kinetics and loading capacity for trivalent chromium can be found.
Factors which Affect Product Marketability
In Task 2 it was determined by surveying potential chromium users that the best candidate for purchasing our product would be the tanning industry. In this industry, many operators use trivalent chromium sulfate; however, only a concentrated solution or crystalline material would be economic to ship. The purity levels required2 for a 2 gpl solution would be:
< 40 ppm Fe < 10ppmCu < 1 ppmPb.
This represents a required chromium-to-iron and chromium-to-copper concentration ratio of >50/1 and >200/1, respectively.
The latter element is not generally present in the'waste streams at MRS. ~nour research, batch tests indicate that greater than 90 percent of the chromium can be recovered, with this figure probably exceeding 99% for multi-stage counter-current operation. Examining the results of the precipitation tests on purities, the ratio of chromium- to-iron and chromium-to-copper is seen to be 380/1 and 1,320/1, respectively. This indicates that the product produced from precipitation of the purified solution would meet the necessary specifications.
4A- 6 CONCLUSIONS MID RECOMMENDATIONS FOR FU?ZTRE WORK
The following conclusions are reached:
* There appears to be a viable market in the tanning industry for trivalent chromium chemicals providing they are sufficiently pure.
* Solvent extraction using 10% D2EPH.A and 2070 DMOO with an aliphatic diluent at an aqueous-to-organic ratio of 1/1 and a pH of 2.5 can effectively remove the contaminant metals of iron, copper, nickel, cadmium and zinc from a chromium solution without significant chromium extraction in projectzd counter-current operation.
* Concentration of the purified plating waste solution by precipitation and washing of the precipitate appears to be the only viable method of recovery of the three concentration methods which were examined (evaporation, precipitation, and ion exchange). The purified solids exceed the necessary requirements for the tanning industry.
The following are recommendations for future work:
* Solvent stability testing and potential for crud formation (formation of a stable third phase) should be examined in pilot testing. Countercurrent operation is required to test stability and also to firm up operating cost estimates.
* The nature of the anion may be important. Work to date has only been on wastes having a sulfate base. Chlorides probably will have minor interferences; however, fluorides will definitely affect the chelating of iron.
* The stripping of organic which would be determined in the counter-current testing is an important parameter, and also the collection of the stripped metals and their incorporation in the circuit of the treatment system at MRS is an important consideration.
* Sufficient crystalline product should be produced to determine its acceptability in the tanning industry’which is concerned with iron contamination and consistency of product. The presence of iron in any lot above their specifications could result in sigdcant degradation of their product which would only be noticed long after the treatment of leather. This concern requires total product assurances from MRS, and consequently continuous tesiing batch by batch.
4A-7 REFERENCES
1. Ritcey, G.M. and Ashbrook, A.W., Solvent Extraction Part I, Elsevier Science Publishing Co., New York, N.Y., 1984.
2. Telephone conversation: 10/ 10/89 Wayne Chemical Corporation: Mr. Bernard Judd ((414)278-8844).
3. Telephone conversation: 10/10/89 S.B. Foot Tanning Company of Red Wing, MN. They would be please to accept a minimum volume of 200,000 pounds per year of trivalent "iron-free" chromium in the form of chromium sulfate. A solution containing 10% trivalent chromium by weight would be acceptable. (This would be a 15% Cr,O, on a chromic acid basis, which is the usual manner of referring to these solutions.)
f s..
4A- 8 Table 1
necal Ccncentration of Acueous after Conract with Organic: !OZ DZE:I?A, 2117GMCO SinSle Contact Trials
initial cmc. 1836 235 134 423 47 564
10/1 1 201L 185 13 1 a2 43 518 10/1 1.5 1992 159 0 106 40 515 10/1 2 1982 118 0 57 41 497 10/1 2.5 1978 81 0 36 36 4% 10/1 3 1978 52 0 26 33 482
5/1 1 1984 136 ' 3 60 40 523 5/1 1.5 1968 73 0 20 33 509 5/1 . 2 1965 20 0 3 20 459 5/1 2.5 1983 7 0 0 7 329 5/1 3 1963 3 0 0 3 169
2/ 1 1 1964 * 70 0 20 33 512 2/1 1.5 1913 24 0 3 19 450 2/ 1 2 1924 3 0. 3 7 253 2/ 1 2.5 1868 0 0 0 3 77 2/1 3 1669 0 0 0 3 27
1/1 1 1970 36 0 10. 23 513 1/1 1.5 1996 11 0 .4 - 7 163 1/1 2 1927 0 0 0 3 123 1/1 2.5 1749 0 0 0 0 30 1/1 3 1154 0 0 0 0 14 -
1 ...... 1 /2 1891 182 0 152 42 490 ...... , ..:- 1/2 1.5 2048 113 0 44 29 350 ._.: 1/2 2 2018 32 0 11 11 11 .. ... 1 /2 2.5 1911 7 0 3 3 27 ...... , .-...... :. . ... 1 /2 3 1505 0 0 3 0 10 ...... ~ . 1/5 1 1920 166 0 86- 35 459
1 /5 1.5 ' 1805 83 0 21 18 239 1/5 2 1837 15 0 7 7 65 1/5 2.5 1587 3 0 0 3 13 1 /5 3 769 0 0 0 3 10
1/10 1 1527 147 30 36 24 360 1/10 1.5 1513 TI 0 6 6 147 1/10 2 436 3 0 0 0 9 1/10 2.5 1094 3 0 0 0 12 1/10 3 1482 6 0 0 0 21
...
.... :, ...... 4A-9 Table 2
Percent Extraction : lOXQEHPA, 207~)MCOSingle Contact Tests
Ratio PH Cr (%) Hi (%I Fe (%I cu (%) Cd (%) Zn (%I Aq / Org
. 10/1 1 0 21 90 57 9 a 10/1 1.5 0 32 9a 7s. 15 9 10/1 2 0 50 100 87 13 12 10/1 2.5 0 66 100 91 23 12 10/1 3 0 78 100 94 30 15
5/1 1 0 42 100 86 15 7 5/1 1.5 0 69 100 95 30 10 5/ 1 2 0 91 100 99 57 19 5/1 2.5 0 97 100 100 85 42 5/1 3 0 G9 1oa 100 94 70
2/1 . 1 0 70 100 95 30 9 2/ 1 1.5 0 a9 100 99 60 20 2/ 1 2 0 99 100 99 as 55 2/1 2.5 0 100 100 100 94 a6 2/ 1 3 9 100 100 100 94 95
1/1 1 0 85 100 98 51 9 1/1 1.5 0 95 100 99 85 71 1/1 2 0 100 100 100 94 78 1/1 2.5 5 100 100 100 100 95 1/1 3 37 100 L 100 100 100 98
1/2 1 0 23 100 64 li 13 1/2 1.5 0 52 100 90 38 38 1/2 2 0 86 100 97 77 80 1/2 2.5 0 97 100 99 94 95 1 /z 3 18 100 100 99 100 98
1/5 1 0 29 100 80 26 19 1/5 1.5 2 65 100 95 62 58 1 /5 2 0 94 100 98 85 88 1/5 2.5 14 99 100 100 94 98 1/5 3 58 100 100 100 94 98
1/10 i 17 27 ?a 91 49 36 1/10 1.5 18 67 100 99 87 74 1/10 2 18 99 100 100 100 98 1/10 2.5 18.5 59 100 100 100 98 1/10 3 19 98 too 100 100 96
.-
4A- 10 Table 3.
Metat Concentraticn of Aqueous after Contac: uirh Orsanic: 1Gf D2E3PA, 20% CMCG Huttiple Contact Trials (same Aq. mul:iple Or;.) Phase Ratio of T/1 Aq./Org.
ccntac: FH Zn(;Fm)
Initial conc. 2007 ‘ 221 a 140 4L5 49 s oa
-1 1.5 xoa 197 7- 278 44 4C8 2 1.S 1996 1a2 0 124 41 348
3 1.5 1925 161 0 60 33 297 ’ 4 1.5 1902 143 0 27 33 254
1 2 2006 162 0 106 36 265 2 2 1971 95% . 0 13 22 130 3 2 1949 55 0 0 13 65 4 2 1886 33 0 0 7 33
1 2.5 1917 107 0 37 24 107 2 2.5 1901 22 0 0 6 19 3 2.5 1872 7 0 0 0 7 t 2.5 1842 3 0 0 0 ?-
/
.
4A-11 Table 4.
% Ex:.-ac:ion of Metals after Cmcac: uich Organic: 10:: OZfHPA, 2QX OMCO Multiple Ccntac: Trials (same Aq. nwltiple Or;.) Phase! Ratio of l(1 Ac;./Crj.
ccccac: CU(X) Cd(I) ZnG)
1.5 0 11 95 38 11 20 1.5 1 17 1co 72 16 32 1.5 4 27 100 a7 23 42 1.5 5 35 100 94 32 48
2 0 26 . 100 76 25 48
2 2 57 ~ 100 97 55 74 2 3 75 100 100 73 87 2 6 85 100 100 86 93
2.5 5 51 100 92 52 79 2.5 5 90 100 100 87 96 2.5 7 97 100 100 100 99 2.5 8 . 99 too 100 100 99
4A- 12 Percent Extraction: 1 0ZD2 EHPA, 2 0ZD\,r@O Phase Ratio: 10 Ad1 Org
Figure 1. . Percent Extraction: 1O%DZEHPA, ZOZDMOO Phase Ratio: 5 Ad1 Org
4A-13 Percent Extraction: 1OZDE2HP-4, 2OZD1fCC) Phase Ratio: 2 Ad1 Org
SO
I I/ I i i i ! I 40 I" I I 1 * I 10 I i 0 1 1.5 2 2.5 3 PH Figure 3. . Percent Extraction: 10 %DE2 HPL 2 0 ZDMOO Phase Ratio: 1 Aq/l Org
1 1.5 2 2.5 3 PH Figure 3.
4A- 14 Percent Extraction: 1 0ZDQ HPA! 2 0ZDhIOr3 Phase Ratio: 1 Ad3 Org
I 0 - I 1 1.5 2 2.5 3 PH Figure 5, . Percent Extraction: 10 %D2 EHPA, 2 0%D!dOO Phase Ratio: 1 Ad5 Org
Figure 6.
4A- 15 Percent Estrac tion: 1 0 %D2 EHPA, 2 0Z,DM@@ Phase Ratio: 1 Ad10 Org
90
40 j zr-r)’ i
I 10 I I I 0 I i 1.5 2 2.3 3 PH Figure 7.
PH=1.5, Same Aq. Multiple Org. Phase Ratio= l/l 1 20 - cr w Y 100 YR Ni 80 7 ”, Fe €0
40 Cd 20 .. zn 0 I I 1 2 3 e NUmbEf of Ccntccts Figure 8.
4A- 16 PI-I=2.0, Same Aq. Multiple Ow.L Phase Ratio= 1/1
120
1 CO
EO
io
4.3
20 - I ./. 0 I I I I 1 2 3 4
of Ccntccts Figure 9. . PH=2.5, Same Aq. Multiple Org. Phase Ratio= l/i
120
€0-I /
20
U 1 I I I 1 2 3 4
Nwbw of Ccntccts Figure io.
4A- 17
Progress Report
to
Metro Recovery Systems (MRS) 2430 Rose Place Roseville, MN 55113
Minnesota Office of Waste Management Industrial Waste Reduction Grant Program
REDUCTION OF CHROMIUM PLATING WASTES
Task 6
1 Estimation of Process Economics for Recovery of Saleable Chromium Product
Michael Wismer Technical Manager, MRS and Malcolm T. Hepworth Consultant
August 18, 1990 INTRODUCTION
The prior progress report on this project, dated June 15, 1990 covered Task 4A:
TASK 4A: In this prior task optimum conditions for solvent extraction and purification of chromium-bearing solutions were determined in order to minimize metal impurities by examining the effect of varying organic-to-aqueous loading ratios. Also the loading kinetics of the impurity species from the aqueous to the organic phase are to be examined. Methods of concentrating the purified aqueous chromium phase (raffinate) resulting from the extraction process would be examined. These concentration methods included evaporation/crystallization, precipitation, and ion exchange.
The results of the tests performed in the prior task indicated that there appeared to be a viable market in the tanning industry for trivalent chromium chemicals providing the impurity content, especially of iron, was sufficiently low. The optimum conditions of solvent extraction using 10% DZEPHA and 20% DMOO with an aliphatic diluent at an aqueous-to-organic ratio of 1/1 and a pH of 2.5 resulted in a high degree of extraction of iron, copper, nickel, cadmium, and zinc from a chromium solution without significant chromium extraction in a single stage operation. ' Several stages of continuous counter-current operation may be required to bring these levels of impurities to trace levels; however, even in four stages of contact purity levels for a 2gpl chromium solution were 3ppm Ni, In order to concentrate these dilute solutions to a saleable product, three methods of concentration were examined: evaporation and crystallization, precipitation, and ion exchange. Evaporation and crystallization produced a product with a high degree of contamination with sodium sulfate (containing only 2.1% by weight chromium). Ion exchange proved to be ineffective for the cation resins which were employed (IR- 120+, which was recommended by Rohm and Haas). The probable reason was that the loading kinetics was too slow (over fifteen hours of contact was employed resulting in only 12% loading). However, precipitation resulted in a 14.5% chromium salt, which contained 37ppm Cd, lOOppm Cu, 380 ppm Fe, 860ppm Ni and 2700ppm Zn. The primary impurity in this precipitate was sodium sulfate which required washing for its removal. 6-1 TEST RESULTS FOR EXTENSION OF WORK BEGUN IN TASK 4A These prior results required further testing which has been accomplished in the present reporting period. The following tests were undertaken: * All single-stage loading tests were repeated resulting in essentially identical results as previously determined. * Upon further examination of the data, it now appeared that the best conditions for a high degree of purity of solution consistent with process economics is a 2/1 aqueous-to-organic ratio at a solution pH of 2.5. The repeated results on percent extraction for four stages of contact are shown in Figure 1. Sufficient purified solution from four stages of contact under the above conditions was produced in order to provide a precipitate for further examination. Approximately 25 grams of precipitate were produced from the original solution. * The precipitate which was produced by neutralization of the acidic raffinate to a pH of 8.5 with 10 normal sodium hydroxide was washed with a volume of deionized water of approximately one-quarter of the original raffinate volume, applied continuously to the filter cake in order to remove the sodium sulfate. * The resulting product of this procedure was heated to 105OC overnight, resulting in the following duplicate assays PW #1 and PW #2: This information is on the precipitate which was produced by neutralization of the purified raffinate solution by sodium hydroxide. The duplicate assays above indicate that there is a high degree of sodium coprecipitated in the solids indicating that more washing is needed. The loss upon ignition at 950°C for 1/2 hour was 35% with no significant change in sulfur content, but with greatly reduced carbon content. Clearly the sample was contaminated with residual organic resulting in the high reported carbon content. This carbon can be removed by heating in air at 950°C; however, the sulfur content of the treated material was not observed to diminish, indicating that thermal dissociation of chromium sulfate to the oxide does not occur under these conditions. 6-2 Task 6 originally was to be a comparison between hydrometallurgical and pyrometallurgical methods; however, as explained above, the pyrometallurgical approach was not explored but, rather, a more thorough study of the hydrometallurgical approach was undertaken. Also in Task 6, we were to conduct an estimate of capital and operating costs as well as revenues for s full scale operation. This has been done as described in the section below. In the final Task 7, which will be reported on within the next two weeks, a final report will be issued to summarize the prior reports and will include a preliminary design of a pilot test system. DISCUSSION OF RESULTS WITH RESPECT TO PROCESS ECONOMICS One aspect of this study was to determine (Task 1) the assay of representative solutions which were received by MRS. An initial survey of solutions received by MRS was taken to determine the chromium content. The results of this survey were reported in Task 1 in September 1989. Since then a second survey of solutions received in the period September, 1989 through July, 1990 confirms the prior survey. The average chromium assay is approximately 2 grams of chromium per liter. In this latter survey, 276 batches were assayed containing a total of 555,400 gallons of solution. Of this total gallonage, only 10,200 gallons exceeded 10 grams per liter chromium. Three batches from the 276 did exceed a concentration of 100 grams chromium per liter. This result indicates that the actual number of pounds of chromium passing through the plant for processing in any one month for the typical solutions (excluding the highly concentrated solutions) amounted to a little over 800 pounds of chromium. This throughput may have increased since this survey was taken, but it falls far short of the originally estimated quantity of 21,000 pounds of chromium per month. It would appear from this shortfall, that either more chromium solutions are being conserved or recycled at the source, or the original estimate of poundage of chromium to be processed was more than an order of magnitude higher than that which was observed. In recent inquiries of five potential purchasers of chromium chemicals (see references), the question of purity and form of the product continues to be an issue. Our product is a trivalent chromium which is of value only in the tanning industry, or alternatively for a restricted number of platers who use trivalent chromium for dull finish plating. An estimate of the value of trivalent chromium in sulfate form from these conversations is approximately $1.50 per pound of contained chromium. This indicates that the total metal value generated in a month's operation is only a little over $1,200. In conversations with Henkel, Inc.' and Hazen Quinn Research, Inc?, capital costs for a 90,000 gallon per month operation were roughly estimated to be $55,000 plus installation in the existing space within the MRS plant. The size of such a plant for reactors, storage vessels and mixer-settlers is projected to be approximately 8 by 18 feet in an area of height of approximately 6 feet. This system could readily be accommodated within existing space available at MRS. In addition to the solvent extraction equipment, other capital equipment would have to be purchased to complete the recovery unit. Major items would be: holding tanks, a precipitation reactor, ventilation fans and duct work, and a membrane filter press to allow for washing of filter cakes. These added equipment costs would amount to $145,000, bringing the total required capital to $200,000. Installation and engineering costs would 6-3 increase the total capital expenditure to approximately $300,000. (See Appendix A for a break-down of capital costs. Operating costs of the solvent extraction circuit can only be determined through continuous counter-current plant studies, but should be of the order of magnitude of 1 cent per gallon treated. To this figure must be added the cost of precipitation and washing of the precipitate, cost of neutralization reagent, and cost of drying the product, packaging, and continuous assaying for product quality. We estimate the total operating costs to be in the range of eight to fifteen cents per gallon. The operating costs are subject to a wide range of variability especially in start up operations. Also to be considered in the process economics is a savings in landfilling of the products of precipitation of the chromium solutions, if not treated. Each pound of untreated chromium would be equivalent to about 5 pounds of sludge if precipitated with lime. The disposal costs of this sludge are currently of the order of about $500 per ton as of the time of writing (8/90). REFERENCES 1. Telephone conversation: 4/24/90, Henkel Corporation; subject, economic estimate:- Mr. Jerry Dorlac (602)622-8891. 2. Telephone conversation: 4/24/90, Hazen Quinn Corporation; subject, economic estimate:- Mr, Rick Quinn (303) 295-2872. \ 3. Telephone conversation: 10/10/89, and 6/90, Wayne Chemical Corporation; subject, product use and purity, Mr. Bernard Judd, Technical Sales Representative, (414) 278- 8844. Wayne Chemical ships a 15% Cr,O, (10% Cr) solution to tanners. This solution contains 4. Telephone conversation: 10/10/89 S. B. Foot Tanning Company of Red Wing, MN. They would be pleased to accept a minimum volume of 200,000 pounds per year of trivalent "iron-free" chromium in the form of chromium sulfate. A solution containing 10% trivalent chromium by weight would be acceptable. (This would be a 15% Cr,O, on a chromic acid basis, which is the usual manner of referring to these solutions.) 5. Telephone conversation: 6/90, Occidental Chemical; subject, product use and purity, Mr. Russ Morgan, Supervisor, R and D, (800) 828-1144. They are very interested in efforts to recycle chromium. Would like to work with MRS if a sufficiently large sample can be obtained (200 g of solids). Send to 2801 Long Road; Grand Island, N. Y. 14072. 6. Telephone conversation: 7/90, Occidental Chemical; subject, product use and purity:- Mr. Paul Walker, Marketing Manager of Chromium Chemicals, (800) 828-1144. 6-4 7. Telephone Conversation: 7/90 Engelhard; subject, product use and purity:- Dr. Don Snyder, Director of R and D Technology, (216) 360-5013. Engelhard produces a 17% Cr' " product with Fe, Ni, Zn, Cu,and Pb below detection limits (presumably c 1 PP4 8. Telephone Conversation: 7/90 Blue Grass Chemical, product use and purity:- Mr. John Lyle, Technical Sales Representative, (812) 948-1115. 6-5 Dominion Tanners 1601-T Church Ave Winnipeg, Man., Canada APPENDIX a Wavne EAW131T 4 546 SOUTH WATEB SK?E5 MILWAUKEE. WISCC)NSIN 53~r)L.O15? TELEPHONE: (41.1) 273-3812 FAX: (414) 278-0848 HARCROS CHEMICAL GROUP Yes, But uuuld de@ on c0nt"ts 2. PTnat form of chromium compound would iou consider rec:iving? C'iioclc acid (hexavalent)? Chromk (trivalent) sulfzte? Chromic (trivalent) hydroxide? 0 ther? wc (~dmt)Sulfate with ratio of: Total Cbrdm as cr 1 Total Chraniun as cr 3. What degrt: of purity is required? (If possible indicate penalty elements,) 1. No Materidls on List 2,Wts. Pb-lpImMax- Ni-lOpFml- Fe- 5Oppnl@x cu-1oPpm- 4. What mkinz;?l volume (Ibs/yr on a ckromium basis) would you consider of in tertst? 6. Caslzenu. P. 0. BOX 723, Nlec~aFalls, NY 14302 SCO/752-5151 Deteraent & Sueciaitv Products Dlvlsion SODlUM BICHROMATE Typical AnaiysJs Technical Grads Tachnical Grads Llquor c iysta I3 As is Basts NaiCIZO,* 2Hp0 101%' 69-70% Chlcride es CI C.03% 0.2?5 Suliara e9 so, 0.1 4; 0.2% Vanadium as V O.GG3fb 0.02?4 Me&s Fsdirai Speslflcaticn O-S-5$5'2(i) 'The arzccr;t aver 100% Is due la idzfi:!snzl oe,er.&yhg :o rsdxz c2khg. Fhyslcal Propsrtfes Chemiczl Nmes Sssiun Elc5romzta Dihydizte (Ccnmon Nare) Scciun Dichramais Cihyc'ttte (Technical Neme) Fsrnula Na,Sr,O, 2Y20 Cotor 8rfGht OranGe Crys:z!s, Ruby Eec! Liqucr Moleculer Weight 292.00 Behwior cn Heating Loses watsr of crystalirztion 2i 84.6OC. (1842OF) Anhydrcus Salt melts st 358.7OC. (674.1 OF) Dacmposes abcve 4CO O C. (752 F) Denslty 2.35 @ 25°C Bulk Density - Crystal LO088 77.0 Ib./cu. ft. avsrage Tapped 90 Ib./cu. ft. average Solubility Highly soluble in water (74.0% at 25°C) Heat of Solution Endothermlc - 28.2 czUgram (-50.8 BTUnb.) Stability in Air At 25 a C, dellq~€" at relative humidities above 54% . pH @ 25OC 3.0 4.6 dependlng cn concentration Transltlon in Solutlon 84.8" C (184.2'F) Packages Tank Cars 13,000 gallcn lnsuleted tmk m5 Tank Trucks 2,500 to 3,000 gallcns equipped for unloading by gravrty or wiih customers' alr or pump Ba~s 60 Ibs. net, 61 Ibs, gross, Multiwll Kraft Paper w!th PE Uner Crums 1GO IDS. net, 106.5 Ibs. Cross, Sted Drum 100 Ibs. net, I 05.5 Iks. gross, Fibre Drum 4C0 lbs, nst 414,s Ibs. gross, Fibre Drum 620 IDS. net 421.5 Ibs. gross, Steel Drum Shlpping Regulatlons Proper Shlpping "ne Scdium Dlchromata - Dry or Uquid . EiUxdCless ORM-A' 'NA 1479 Hazadous Substanca: IiQ 1,000 Ibs, or mcra In a 3ingk packzse 'Regdated for Air Transport Only GP*CFI.d December 1988 *Xx 0cci d e nt a 1 C h em ica ! Corporation b .w0ccicenr.d C%m!cal Center. 3E0 Reinbow Bculevard South r! Sodium Bichromate Liquor (Na,Cr,O, 2H,O (69=70%) Other Heavy Metals Typical in Parts Fer Million ...... Zinc ...... G.0 Cidmium...... <5Do Cobsit,, 1 I I ...... cI0,O Nickei...... 40,o Ccpper...... c5.0 Fhcsphorus...... 2.0 Silver...... <5.0 .. slllca...... B; ...... 40.0 ' Alumirium., ...... SPC.?.T;-5 Decsmbcr 1SZ8 .. I ...... .. .. APPENDIX B DMOO Synthesis: Sodium acetate, 3,7-dimethyloctanal, hydroxylammonium acid sulfate and sodium hydroxide in molar ratios of 0.2, 1.0, and 1.8, respectively, are used in the synthesis. Sodium acetate, hydroxylammonium acid sulfate, and sodium hydroxide are combined and dissolved in sufficient water to give a solution of 35% total salts. 3,7- dimethyloctanal is diluted with an equal amount of kerosene resulting in a 50% solution of 3,7-dimethyloctanal. The two solutions are then combined in a 2 liter beaker and heated on an electric hot plate to 800Cfor 3 hours. During the reaction the mixture is continuously stirred with a three blade impeller. After three hours DMOO is present in the organic phase which is then separated from the aqueous phase in a separatory funnel. The aqueous phase is discarded. The organic is washed several times with equal volumes of water to remove impurities. The resulting organic phase is approximately 45% DMOO and is now ready to be employed in the solvent extraction tests. Table 1. Metal Concentration of Aqueous After Contact with Organic: 10% DZEHPA, 20% DMOO Multiple Contact Trials (Same Aqueous, iMultiple Organic Contact). Phase Ratio of 1/1 Aq.Org. Initial conc. 2007 Zit 140 445 49 5ca 1 1.5 2008 197 7 278 44 408 2 1.5 1996 182 0 124 C1 343 3 1.5 1925 161 0 60 38 297 4 1.5 1902 143 0 27 33 256 1 2 2006 162 0 106 36 265 2 2 1971 95 0 13 22 130 3 2 1943 55 0 0 13 65 4 2 1886 33 0 0 7 33 t 2.5 1917 ,107 .o 37 24 107 2 2.5 1901 22 0 0 6 19 3 2.5 tan 7 0 0 0 7 4 2.5 1842 3 0 0 0 7 Table2. Percent Extraction of Metals After Contact with Organic: 10% D2EHPA 20% DMOO Multiple Contact Trials (Same Aqueous, Multiple Organic Contact). Phase Ratib of 1/1 Aq./Org. Contact 1.5 0 11 95 38 11 20 1.5 1 17 100 72 / 16 32 1.5 4 27 100 87 23 42 1.5 5 35 100 94 32 48 1 2 0 26 100 76 26 48 - 2 2 2 57 100 97 55 74 3 2 3. 75 100 100 73 a7 .4 2 6 85 100 ' 100 86 93 2.5 5 51 100 92 52 79 2.5 5 90 100 100 a7 96 2.5 7 97 too 100 100 99 2.5 a 99 too 100 100 99 4-10 Table 3. Metal Concentration of Aqueous After Contact with Organic: 10% D2EHPA, 20% DMOO Multiple Contact Trials (Same Organic, Multiple Aqueous Contact). Phase Ratio of 1/1 Aq./Org. Initial CCX. 2007 221 140 445 47 5oa 1 1.5 to4a i 98 10 222 LL 416 2 1.5 2025 216 7 345 46 4 75 3 1.5 1965 197 10 390 45 439 4 1.5 1986 202 20 363 46 457 1 2 1971 147 a 74 33 221 2 2 1975 21 1 0 194 47 388 3 2 2009 219 0 297 L6 457 4 2 2044 21 1 0 335 4s 472 1 2.5 2024 61 .o 13 13 57 2 2.5 2063 220 0 83 L7 ---1FO 3 2.5 2025 25 2 0 186 56 323 4 2.5 2029 249 0 332 53 412 . Table4. Percent Extraction of Metals After Contact with Organic: 10% D2EHPA, 20%A DMOO Multiple Contact Trials (Same Organic, Multiple Aqueous Contact). Phase Ratio of 1/1 Aq./Org. Contact 1 1.5 0 10 93 50 11 18 2 1.5 0 2 95 22 5 7 3 1.5 7 11 93 12 8 14 4 1.5 1 9 a6 17 5 10 1 2 2 33 100 83 . 32 57 2 2 2 5 100 .. 56 4 24 3 2 0 1 100 33 7 10 4 2 0 4 100 25 0 7 1 2.5 0 73 100 97 72 a9 2 2.5 0 1 100 81 5 63 -, 3 2.5 0 0 ,100 58 0 34 4 2.5 0 0 100 27 . 0 19 4-11 pH2.5, Same Aq. Multiple Org. 120 .?n 1 co # -Cr I ~ - Ni .-5 80 4 V 0 L Fe X LLI _2_ _v Cd - = J .c I- Zn Figure 6. Solvent Extraction Tests SAM0 PH=1.5, Same Org Multiple - Phase Ratio= 1/1 m. 80 -. Eo -- 40 \ Figure 7. Solvent Extraction Tests SOMA 4-8 PT-I=2.0, Same Org. Multiple Aq. Phase Ratio= 1/1 Figure 8. Solvent Extraction Tests SOMA PH=2.5, Same Org.?Multiple Aq. -Phase Ratio= 1/1 120 -I- cr _t_ -Ni -Fe cu -3t- Cd -A1 0 I,_-I I I I 1 2 3 4 bbrnb of Caitmls Figure 9. Solvent Extraction Tests SOMA 4-9 p r. APP ndix A Ex ibit 1 , UNIVERSITY OF MINNESOTA Mineral R. sources R S arch Center TNlN ClTlES 56 East River Road I Minneapolis, Minnesota 55455-0205 I I (612) 625-3344 I TWX 91 0 576 2955 August 2, 1989 Dear Sir, I would appreciate your response to this questionnaire, or alternatively a response from someone in your company which may have an interest in recycling chromium chemicals. The Minnesota Pollution Control Agency.has entered into a program with a local company which receives plating wastes from a great majority of platers in the Twin Cities metropolitan area. This program' undertakes to separate chromium from other plating constituents for recovery and recycle at a potentially low cost. Your assistance in answering the questionnaire would be appreciated. Very truly yours, MT.He p wor t h Professor hlTTHpr Enclosure CHROQUES.LTR APC idix A EX ibit 2 UNIVERSITY OF MlNNESOTA Mineral Sesources Research Center TWIN CITIES 58 East River Road Minneapolis, Minnesota 55455-0205 (612) 625-3344 TWX 91 0 576 2955 August 14, 1989 Dezr Sir, I an writing you as a conpany which may have inter,ests in tanning chemicals. Yoxi response to this questionnaire would be appreciated if you have an interesr in recychg chromium chemicals. The ~W~nesotaPollution Control Agency has entered into a program wirh a loca! conpany which receives plating wastes from a great majority of platers il? the Twin Cities metropolitan area. This program undertakes to separate chromium from other plating constituents for recovery and recycle at a potentially low cost. Your assistance in answering the questionnaire .would be apprcciated. MT.I&ep worth Professor MTH:pr Enclosure CHROQUELLTR AppendixI A Exhibit 1 I I I UNIVERSITY OF MINNESOTA Mineral Resources Research Center , TWINCITIES 56 East River Road I Minneapolis, Minnesota 55455-0205 (612) 625-3344 TWX 910 576 295s' August 2, 1989 Dear Sir, I would appreciate your response to this questionnaire, or alternatively a response from someone in your company which may have an interest in recycling chromium chemicals. The Minnesota Pollution Control Agency%hasentered into a program with a local company which receives plating wastes from a great majority of platers in the Twin Cities metropolitan area. This program' undertakes to separate chromium from other plating constituents for recovery and recycle at a potentially low cost. Your assistance in answering the questionnaire would be appreciated. Very truly yours, MT.Hepworth Professor MTH:pr Enclosure CHR 0QUES.LTR ! I ~ UNIVERSITY OF MINNESOTA Mineral Resources Research Center 1 TWINCITIES 56 East River Road Minneaoolis, Minnesota 55453-0205 (612) 625-3344 TWX 910 576 2955 August 14, 1989 Dezr Sir, I an writing you as a conpany which may have inter.ests in tanning chemicaIs. Your response to this questionnaire would be appreciated if you have an interesr in recycfing chromium chemicals. T'ne Mmesota PoIIution Control Agency has entered into a program with a loca! conpany which receives plating wastes from a great majority of platers iil the Twin Cities metropolitan area. This program undertakes to separate chromium from other pIating constituents for recovery and rtcycIe at a poten?ially low cost. Your assistance in answering the questionnaire would be appreciated. MT.bYepworth Professor MTH:pr Endosure CHROQUES.LTR . APPENDIX A EXEIBIT 3 OuESTIONNAIRE ON CHROMIUM RECOVERY There rczy be potential to produce a semi-pure chromium chemical from platins wastes for resale to the plating industi:/ oi other consumers. If you have any interest in this matter would you pIease take a few minutes to ' answer the ques7ionnaire beIow which is part of a study for the Minnesota Pollution ControI Ageacy. 1. Would your cocigany have any inteiest in receiving semi-pure chromium conpounds for subsequent resale to the plating industry or other potential consumers? 2. Wnat form cf CSiomium compound would YOU consider receiving? Chromic 2 cid (heI a v a1e n t ) ? Chronic (trivalent) sulfate? , Chromic (trivaIent) hydroxide? Orher? 3. What degree of purity is required? (If possible indicate penalty elements.) .- 4. What minimum volume (lbs/yr on a chromium basis) would you consider of interest? 5. What price range would you consider (state basis)? 6. Comments. . APPEXDIX A TABLE 1 Witco Chemical Corp. Allied-Kelite Div. 2400 E. Devan Avenue Des Plaines, IL 60018 Ashland Chemical Co. Chemicals & Solrents Div. P.O. Box 2219 Columbus, OH 43216 Essex Industrial Chemicals, Inc. 1401 Broad St. Clifton, NJ 07015 Dupont 1007 Market St. Wilmington, DE 19598 Harshaw Chemical Co. 1945 E 97th St. Cleveland, OH 44106 Learonal, Inc. 272 Buffalo Avenue Freeport, NY 07065 MacDermid, Inc. 50 Brookside Rd Waterbury, CT 06720 Udylite 21441 Hoover Rd. Warren, MI 48089 Brent Chemicals Intl., Ltd. 95 Commerce Rd. Stanford, CT 06904 Startite Chemicals, Inc. . , 1319 West North Avenue Chicago, IL -60622 U.S. Chemical Corp. P.O. BOX5-T Babson Park, MA 02157 Admiral Chemical Co., Inc. P.O. Box 3398 Peabody, MA 01961 Aran Isles Chemicals, Inc. I-T Marbee Rd, Rockport, MA 01966 APDPXDIX A EXBIBIT 3 OUESTTONNAIRE ON CHROMIUM RECOVERY There may be potential to produce a semi-pure chromium chemical from platins wastes for resale to the pIating industy4 or orher consumers. If you have any interes1 in this matter would you please take a few minutes to answer the questionnaire below which is part of a study for the Minnesota PolIution ControI Agency. 1. Would your corqany have any interest in receiving semi-pure chromium compounds for subsequent resde to the plating industry or other potsntial consumers? 2. What form of chromium compound would YGU consider rec:iving? Chromic acid (hexavalent)? Chronic (trivalent) sulfate? , Chromic (Trivalent) hydroxide? Orher? 3. What desret of purity is required? (If possible indicate penalty elements.) .- 4. What minimum volume (lbs/yr on a chromium basis) wouId you consider of interest? 5. What price range would you consider (state basis)? 6. Comments. APPENDIX A TABLE 1 Witco Chemical Corp. Allied-Kelite Div. 2400 E. Devan Avenue Des Plaines, IL 60018 Ashland Chemical Co. Chemicals & Solrents Div. P.O. Box 2219 Columbus, OH 43216 Essex Industrial Chemicals, Inc. 1401 Broad St. Clifton, NJ 07015 Dupont 1007 Market St. Wilmington, DE 19898 Harshaw Chemical Co. 1945 E 97th St. Cleveland, OH 44106 Learonal, Inc. 272 Buffalo Avenue Freeport, NY 07065 MacDermid, Inc. 50 Brookside Rd Waterbury, CT 06720 Udylite 21441 Hoover Rd. Warren, MI 48089 Brent Chemicals Intl., Ltd. 95 Commerce Rd. Stanford, CT 06904 Starlite Chemicals, Inc. 1319 West North Avenue Chicago, IL -60622 U.S. Chemical Corp. P.O. BOX 5-T Babson Park, MA 02157 Admiral Chemical Co., Inc. P.O. Box 3398 Peabody, MA 01961 Aran Isles Chemicals, Inc. I-T Marbee Rd. Rockport, MA 01966 33 Gerrard St. Huntington, NY 11743 Alloychem, Inc. 641 Lexington Ave. New York, NY 10007 American Nickel Alloy Mfg. Corp. 25 Vesey St. New York, NY 10007 Leico Industries, Inc. Fisk Bldg. 250 W. 57th St. New York, NY 10107 Post, E.L., & Co. 233 Broadway New York, NY 10279 United Mineral & Chemical Corp. 129-133 Hudson St. New York, NY 10013 Materials Research Corp. Rte. 303 & Glenshaw St. Orangeburg, NY 10962 . -. Aremco Products, Inc. 21 Snowden Ave. Ossining, NY 10562 Pure Tech, Inc. 19-A Old Albany Post Rd. P.O. Box 688 Ossining, NY 10562 International Advanced Materials P.O. Box 572 Dept. TR 16 Lafayette Ave. Suffern, NY 10901 Precise Alloys, Inc. 43-R State St. Westbury, NY 11590 Astro Met Associates, Inc. 9974 Springfield Pike Dept. G. Cincinnati, OH 45215 Mallinckrodt, Inc. 675-T McDonnell Blvd. St. Louis, MO 63134 Atlantic Equipment Engineers 13 Foster St. P.O. BOX 18 I-T Bergenfield, NJ 07621 Howmet Turbine Components Corp. Roy St. P.O. Box 371-T Dover, NJ 07802 Alcan Aluminum Corp. P.O. BOX 290-T Elizabeth, NJ 07207 Superpure Chemetals Inc. 23T Woodbine Rd. . Florham Park, NJ 07932 Commercial Crystal Laboratories 3254 Dalziel Rd. Linden, NJ 07036 . Baker, J.T., Chemical Co. 223 Red School Lane Dept. LB-TR Phillipsburg, NJ 08865 Reade Metals and Minerals Corp. 45 W. River Rd. Suite 200 Rumson, NJ 07760 Vermont Minerals Ltd. Box 210 Wenonah, NJ 08090 Belmont Metals Inc. 320 Belmont Ave. Brooklyn, NY 11207 Atomergic Chemetals Corp. 91-T Carolyn Blvd. Farmingdale, NY 1 1735 Metals Mart P.O. Box 1267 Great Neck, NY 11023 Mundex Metals Corp. 33 Gerrard St. Huntington, NY 11743 Alloychem, Inc. 641 Lexington Ave. New York, NY 10007 American NickeI Alloy Wg. Corp. 28 Vesey St. New York, NY 10007 Leico Industries, Inc. Fisk Bldg. 250 W. 57th St. New York, NY 10107 Post, E.L., & Co. 233 Broadway New York, NY 10279 United Mineral & Chemical Corp. 129-133 Hudson St. New York, NY 10013 Materials Research Corp. Rte. 303 & Glenshaw St. Orangeburg, NY 10962 Aremco Products, Inc. 21 Snowden Ave. Ossining, NY 10562 Pure Tech, Inc. 19-A Old Albany Post Rd. P.O. Box 688 Ossining, NY 10562 International Advanced Materials P.O. Box 572 Dept. TR 16 Lafayette Ave. Suffern, NY 10901 Precise Alloys, Inc. 43-R State St. Westbury, NY 11590 Astro Met Associates, Inc. 9974 Springfield Pike Dept. G. Cincinnati, OH 45215 Mallinckrodt, Inc. 675-T McDonnell Blvd. St. Louis, MO 63134 AtIantic Equipment Engineers 13 Foster St. P.O. BOX 18 1-T Bergenfield, NJ 07621 Howmet Turbine Components Corp. Roy St. P.O. BOX 371-2- Dover, NJ Or802 Alcan Aluminum Corp. P.O. BOX 290-T Elizabeth, NJ 07207 Superpure Chemetals Inc. 23T Woodbine Rd. . Florham Park, NJ 07932 Commercial Crystal Laboratories 325-T Dalziel Rd. Linden, NJ 07036 . Baker, J.T., Chemical Co. 223 Red School Lane Dept. LB-TR Phillipsburg, NJ 08865 Reade Metals and Minerals Corp. 45 W. River Rd. Suite 200 Rumson, NJ 07760 Vermont Minerals Ltd. Box 210 Wenonah, NJ 08090 Belmont Metals Inc. 320 Belmont Ave. Brooklyn, NY 11207 Atomergic Chemetals Corp. 91-T Carolyn Blvd. Farmingdale, NY 1 1735 Metals Mart P.O. Box 1267 Great Neck, NY 11023 Mundex Metals Corp. Hamblet & Hayes Co. Colonial Rd. P.O. Box 730 Salem, MA 01970 Reactor Experiments Inc. 963-T Terminal Way San Carlcs, CA 94070 Electronic Space Products International 31 194-T LaBaya Dr. Westlake Village, CA 94402 Vertech Alloy Components, Inc. 2997 S. Tejon St. Englewood, CO 80110 Mackay A.D., Inc. 104 Old Kings Hwy North P.O. Box 1612 Darien, CT 06820 Superior Plating Company 1 Lacey Place Southport, CT 06490 American Minerals 301-T Pigeon Point Rd. New Castle, DE 19720 Dover Industrial Chrome, Inc. 2931 N. Campbell Ave. Chicago, IL 60618 NSM of Illinois, Inc. P.O. Box 58/Dept. JG Oglesby, IL 61348 Maremont Manufacturing Service 291-T North St. Saco, ME, 04072 Nuclear Metals Inc. 2229 Main ST. Concord, MA 01742 Hille & Mueller, Inc. 287A Shaker Rd P.O. Box 213 East Longmeadow, MA 01028 BruneI1, A.A. Electroplating Corp. 41-1 Sutton Lane Worcester, MA 01603 I Cooper Metallurgical Corp. P.O. Box 09298 Cleveland, OH 44109 EIectroIizing Corp. of Ohio 1325-T E. 152nd St. Cleveland, OH 441 12 Nord Resources Corp. 81 I I-T Timberlodge Trail Dayton, OH 45459 Chemalloy Company, Inc. P.O. Box 350 Bryn Maw, PA 19010 . International Chromium Plating Co. ’ 2-T Addison Place Providence, RI 02909 Industrial Chrome Plating Co. 3007-3009 Summer Ave. Memphis, TN 38112 Cerac Inc. P.O. Box 1178 Milwaukee, WI 53201 Hamblet & Hayes Co. Colonial Rd. P.O. Box 730 Salem, iMx 01970 Reactor Experiments Inc. 963-T Terminal Way San Carlos, CA 94070 Electronic Space Products International 31 194-T LaBaya Dr. Westlake Village, CA 94402 Vertech Alloy Components, Inc. 2997 S. Tejon St. Englewood, CO 80110 Mackay A.D., Inc. 104 Old Kings Hwy North P.O. Box 1612 Darien, CT 06820 Superior Plating Company 1 Lacey Place Southport, CT 06490 American Minerals 301-T Pigeon Point Rd. New Castle, DE 19720 Dover Industrial Chrome, Inc. 2931 N. Campbell Ave. Chicago, IL 60618 NSM of Illinois, Inc. P.O. Box 58/Dept- JG Oglesby, IL 61348 Maremont Manufacturing Service' 291-T North St. Saco, ME. 04072 Nuclear Metals Inc. 2229 Main ST. Concord, MA 01742 Hille & Mueller, Inc. 287A Shaker Rd P.O. Box 213 East Longmeadow, MA 01028 Brunell, A.A. Electroplating Corp. 41-1 Sutton Lane Worcester, MA 01603 .. Cooper Metallurgical Corp. P.O.Box 09298 Cleveland, OH 44109 Electrolizing Corp. of Ohio 1325-T E. 152nd St. Cleveland, OH 441 12 Nord Resourcts Corp. 81 1 I-T Timberlodge Trail Dayton, OH 45459 Chemalloy Company, Inc. P.O. Box 350 Bryn Mawr, PA 19010 International Chromium Plating CO. ’ 2-T Addison Placc Providence, RI 02909 Industrial Chrome Plating Co. 3007-3009 Summer Ave. Memphis, TN 38112 Cerac Inc. P.O. Box 1I78 Milwaukee, WI 53201 APPENDIX A TABLE 2 Allied Leather Corporation/ Crown Leather Finishing 422 N. Perry Strzet P.O. Box 663 Johnston, NY 12095 Amdur Braude Riley, Inc. 226 Salem Street P.O. Box 545 Woburn, MA 01801 American Leather Manufacturing Co. k2195 Elizabeth Avenue Rahway, NJ 07065 American TarLnin,a gC Leather Company 312 W. Solomon Street Griffin, GA 30223 Andre Manufacrshg Cop P.O.5039 Newark, NJ 07105 Badger State Tanning Corp. 321 North 25th Street Milwaukee, WI 53233 1 i: \ Blackhawk TaTlrriTIg Company, Ltd. 1000 West Bruce Street Milwaukee, WI 53204 The Blueside Companies, Inc. Division of Prime Tanning Co., Inc. 205 Florence Road P.O. Box 383 St. Joseph, MO 64502 Brown Shoe Company 8300 Maryland Avenue P.O. Box 354 S t. Louis, MO 63 166 W.D. Byron & Sons, Inc. Division of Garden State Tanning 312 North Conocoheague Street Williamsport, MD 21795 . Caldelle Ltd. 12205 West Pic0 -BIvd. Los hgeles, CA 90064 Calnap Tanning Company P.O. Box 2190 Napa, CA 94555 Camden Tanning Corp. 116 Washington Street P.O. Box C Camden, ME 04843 Cantonis Le ath er Company 855 East Pine Street P.O. Box 338 Tarpon Springs, FL 33589 Carr Leather Company 500 Boston Street P.O. Box 270 Lm,MN 01903 Carville National Leather Corp. Knox Avenue P.O. Box 40 \’ Johnstown, NY 12095 Caspel Corporation 2642 N.W. 21st Terrace Miami, FL 33142 Classic Leather Corporation 126 West Fulton Street Johnstown, NY 12095 . Coey Tanning co~,hc. Haley Road Wartrace, “PI 37183 Colomer USA, Ltd. 228 W. 38th Street New York, NY 10018 Columbia Impex Corp. 171 Madison Avenue New York, NY 10016 Comeaut Leather, Inc. West Adams Street P.O. Box 60 . Conneaut, OH 44030-1160 CromwelI Leather Comuany.L -. INc. 715 Mamaroneck Ave. Mamaroneck, NY 10543 Danfield Incorporated 3045 E. 12th Street Los Angeles, CA 90023 APPENDIX A TABLE 2 Allied Leather Corporation/ Crown Leather Finishing 422 N. Perry Street P.O.Box 663 Johnston, NY 12095 Amdur Braude Riley, Inc. 226 Salem Street P.O.Box 548 Wobum, MA OlSOl American Leather Manufacturing Co. k2195 Elizabeth Avenue Rahway, NJ 07065 American Tarining &L Leather Company 312 W. Solomon Street Griffin, GA 30223 Andre Manufactwing Corp. P.O.5039 Newark, NJ 07105 Badger State Tanning Corp. 321 North 25th Street Milwaukee, WI 53233 Blackhawk Tanning Company, Ltd. 1000 West Bruce Street Milwaukee, WI 53204 - The Blueside Companies, Inc. Division of Prime Taming Co., Inc. 205 Florence Road P.O. Box 383 St. Joseph, MO 64502 Brown Shoe Company 8300 Maryland Avenue P.O. Box 354 St. Louis, MO 63166 W.D. Byron & SOILS,Inc. Division of Garden State Tanning 312 North Conocoheague Street Williamsport, MD 21795 . Caldelle Ltd. 12205 West Pic0 -Blvd. Los Angeles, CA 90064 Calnap Tannins Company P.O. Box 2190 Napa, CA 94558 Camden Tanning Corp. 116 Washington Street P.O.Box C Camden, ME 04343 Cantonis Leather Company 355 East Pine Street P.O.Box 338 Tarpon Springs, FL 33589 Carr Leather Company 500 Boston Street P.O. Box 270 Lynn, MN 01903 Carville National Leather Corp. boxAvenue P.O. Box 40 \ Johnstown, NY 12095 Caspel Corporation 2642 N.W.21st Terrace Miami, FL 33142 Classic Leather Corporation 126 West Fulton Street Johnstown, NY 12095 Coey Tanning Col., hc. Haley Road Wartrace, TN 37183 Colomer USA, Ltd. 228 W. 38th Street New York, NY 10018 Columbia hpex Corp. 171 Madison Avenue New York, NY 10016 Conneaut Leather, Inc. West Adams Street . * P.O.Box60 Conneaut, OH 44030-1160 CromwelI Leather Company, INc. 715 Mamaroneck Ave. Mamaroneck, NY 10543 Danfield Incorporated 3045 E. 12th Street -_ Los Angeles, CA 90023 Day Leather Corporation 817 Kav Street P.O. Box 1131 Addison, IL 60101 Del-Tan Corporation 235 West 56th street, Suite 28M New York, NY 10019 Delta Tanning Corporation P.O. Box 2 1615 51st Street North Bergen, NJ 07047 Disbrok Trading Company, Inc. 34-18 Northern Blvd. Long Island City, iW 11101 \ Dreher Leather Mfg. Corp. 49 Vesey Street Newark, NJ 07105 Eagle Ottawa Leather Company 200 N. Beechtree Street Grand Haven, MI 49417 Edsim Leather Co., Inc. 242 West 30th Street New York, NY 10001 Empire State Leather Corp. 636 Greenwich Street (Comer of Morton Street) New York, NY 10014 Essex Tanning Corporation 715 Mamaroneck Ave Mamaroneck, NY 10543 EUR-AM Leather Co oration 102 W 38th Street, 6th'R . New York, NY 10018 * Excel Tanning Corporation 715 Mamaroneck Avenue Mamaroneck, NY 10543 Fashion Tanning Company, INc. P.O.Box 1220 Gloversville, NY 12095 Feuer Leather Group 3 Park Avenue New York, NY 10016 : Paul Flagg, Inc. 2200 South Austin Street Milwaukee, WI 53207 S.B. Foot Tanning Co. Bench Street Red Wing, Mii 55066 AF. Gallun & Sons Corp. 1318 North Water Street P.O. Box 533 Milwaukee, WI 53201 Garden State Tarrning 215 Lexington Avenue New York, NY 10016 Garlin & Co., Inc. 66-D River Road Hudson, NH 03051 Gamer Booth, Lnc. 24 Main Street P.O. Box 367 Peabody, MA 01960 AL. Gebhardt Co. . 1237 West Bruce Street P.O. Box 1164 Milwaukee, WI 53201 Genesco, Inc. Genesco Park 8652 Nashville, TN 37202 Golden Leather Company 3063 Bandini Blvd. Los Angeles, CA 90023-0983 Gunnison Brothers, Inc. 9041 Tannery Road P.O. Box 327 Girad, PA 16417-0327 Hemarm Oak Leather Co. 4050 North First Street St. Louis, hi0 63147 Hemes Leather Corp. 45 West 34th Street, Rm 1103 New York, NY 10001 Day Leather Corporation 817 Kay Street P.O. Box 1131 Addison, IL 60101 Del-Tan Corporation 235 West 56th street, Suite 28M New York, NY 10019 Delta Tanning Corporation P.O. Box 2 1615 51st Street North Bergen, NJ 07047 Disbrok Trading Company, Inc. 34-18 Northern Blvd. Long Island City, NY 11101 Dreher Leather Mfg. Corp. 49 Vesey Street Newark, NJ 07105 Eagle Ottawa Leather Company 200 N. Beechtree Street Grand Haven, MI 49417 Edsim Leather Co., Inc. 242 West 30th Street New York, NY 10001 Empire State Leather Corp. 636 Greenwich Street (Comer of Morton Street) New York, NY 10014 Essex Tanning Corporation 715 Mamaroneck Ave Mamaroneck, NY 10543 EUR-AM Leather Co oration 102 W 38th Street, 6th'K . New York, NY 10018 Excel Tanning Corporation 715 Mamaroneck Avenue Mamaroneck, NY 10543 Fashion Tanning Company, INc. P.O. Box 1220 Gloversville, NY 12095 Feuer Leather Group 3 Park Avenue New York, NY 10016 Paul FIagg, Inc. 2200 South Austin Street biilwaukee, WI 53207 S.B. Foot Tanning Co. Bench Street Red Wing, Mix 55066 AF. Gallun & Sons Corp. 1518 North Water Street P.O. Box 533 Milwaukee, WI 53201 Garden State Tanning 215 Lexington Avenue New York, hi 10016 Garlin & Co., Inc. 66-D River Road Hudson, NH 03051 Garner Booth, Inc. 24 Main Street P.O. Box 367 Peabody, MA 01960 A.L. Gebhardt Co. 1237 West Bruce Street P.O.Box 1164 Milwaukee, WI 53201 Genesco, Lnc. Genesco Park $652 Nashville, TN 37202 Golden Leather Company . 3063B~diniBlvd. . . Los Angeles, CA 90023-0983 Gunnison Brothers, Inc. 9041 Tannery Road P.O. Box 327 Girad, PA 16417-0327 Hemarm Oak Leather Co. 4050 North First Street St. Louis, hi0 63147 Hemes Leather Corp. 45 West 34th Street, Rm 1108 New York, NY 10001 Horizon Leather Company 38 Wesi 32nd Street, #810 New York, NY 10001 Horween Leather Company 2015 Elston Avenue Chicago, IL 606 14 Howes Leather Company, Inc. One Batterymarch Park Quincy, MA 02169 Hoyt & Worthen Tanning Corp. 60 Railroad Street Haverhill, MA 01835 Hunt Rankin Main Street Hartland, ME 04943 I.B.P., Incorporated P.O. Box 448 I.B.P. Avenue Dakota City, NE 68731 Intertan Agencies, Inc. 7 134 Gold Street . .' Worcester, MA 01608 Irving Tanning Company Main Street Hartland, ME 04943 JBF Industries, he. 41 West 11th Avenue Gloverde, NY 12078 Johnstown Leather Corp. Railroad Street Johnstown, NY 12095 J.P:Trading Company 47-09 30th Street . Long Island City, NY 11101 Karg Brothers, hc. 6-20 East Fulton Street Johnstown, NY 12095 Kenney Mair Incorporated 237 Albany Street P.O. Box 446 Franklin, MA 02038 I Kroy Tanning Company, Inc. Main Street Hartland, ME 04943 Lackawanna Leather Company P.O. Box 939 Conover, NC 286 13-0939 Lannom Tannerv P.O.Box550 ' Tullahoma, TX 37388 L B International 30 Hub Drive Melville, L.I., NY 11747 Leatherworks Iiiternational Inc. 249A West 29th Street New York, PITY 10001 Libra International Leather, Inc. 259 West 30th Street New York, NY 10001 Loewengart Tanning 209 Oregon Street P.O. Box 300 Mercersberg, PA 17236 Jos. H. Lowenstein & Sons, Inc. . 420 Morgan Avenue Brooklyn, NY 11222 John G. Mahler Company 9012 Chancellor Row Dallas, TX 75356-0067 Marap Leather Import & Export Co., Inc. 678 Broadway New York, NY 10012 Midwest Tanning Co. 1200 Davis Avenue South Milwaukee, WI 53172 A. Mindel & Son, Inc. 4200 Creekside Avenue P.O. Box 6756 Toledo, OH 43612-0756 Modem Leather Corp. 10 First Avenue Peabody, MA 01960 Horizon Leather Company 38 West 32nd Street. X-810 New York NY IOOOI Honveen Leather Company 2015 Elston Avenue Chicago, IL 60614 Howes Leather Company, Inc. One Batterymarch Park Quincy, MA 02169 Hop & Worthen Tanning Corp. 60 Railroad Street Haverhill, MA 01835 Hunt Rankin Main Street Hartland, ME 04943 I.B.P., Incorporated P.O. Box 448 I.B.P. Avenue Dakota City, NE 68731 Intertan Agencies, Inc. ? 134 Gold Street .- Worcester, MA 01608 Irving Ta.nning Company Main Street Hartland, ME 04943 JBF Industries, Inc. 41 West 11th Avenue Gloverde, NY 12078 Johnstown Leather Cop. Railroad Street Johnstown, NY 12095 J.P;Trading Company 47-09 30th Street Long Island City, NY 11101 Karg Brothers, hc. 6-20 East Fulton Street Johnstown, NY 12095 Kenney Mair Incorporated 237 Albany Street P.O. Box 446 Franklin, MA 02038 Kroy Tanning Company, Inc. Main Street Hartland, ME 04943 Lackawanna Leather Company P.O. Box 939 Conover, NC 286130939 Lamom Tannery P.O. Box 550 Tullahoma, TX 37385 L B International 30 Hub Drive Melville, L.I., NY 11747 Leatherworks International Inc. 249A West 29th Street New York, NY 10001 Libra International Leather, Inc. 259 West 30th Street New York, NY 10001 Loewengart Tanning 209 Oregon Street P.O. Box 300 Mercersberg, PA 17236 Jos. H. Lowenstein & Som, hc. . 420 Morgan Avenue Brooklyn, NY 11222 John G. Mahler Company 9012 Chancellor Row Dallas, TX 75356-0067 Marap Leather Import & Export CO., Inc. 678 Broadway New York, NY 10012 Midwest Tanning Co. 1200 Davis Avenue South Milwaukee, WI 53172 A Mindel & Son, Inc. 4200 Creekside Avenue P.O. Box 6756 Toledo, OH 436 12-0756 Modern Leather Corp. 10 First Avenue Peabody, MA 01960 Moench Tanning Company P.O. Box 389 Gowanda, NY 14070 R. Neumann Leathers 66-D River Road Hudson, NH 03051 New Directions in Leather P.O. Box 2297 South Portland, ME 04106 New Jersey Tanning Co., Inc. 410 Frelinghuysen Avenue Newark, NJ 07114 New" Leather Corporation 2101 Ross Avenue Cincinnati, OH 45212 Nippi New York, Inc. One Bridge Plaza, Suite 250 Fort Lee, NJ 07024 Oriental King, Inc. 5 192-C Indian Trail Industrial Pkwy. .- Norcross, GA 30071 Pan American Tanning COT. 318 West Fulton Street Gloversville, NY 12078 Mario Papa & Sons P.O. Box 748 Gloverde, NY 12078 W. Pearce and Brothers, Inc. 38 West 32nd Street, Suite 604 New York, NY 10001 Pell'Italia 218 W 37th Street New York, NY 10018 Peter & Vogel TanTling Co. 1531 North Water Street P.O. Box 745 Milwaukee, WI 53201 W.B. Place & Company 368 West Summer Street Hartford, WI 53027 Prime Tanning Co., Lnc. Sullivan Street P.O. Box 713 Bewick, ME 03901 C.S. Raddatz Leather Company W1240 Elmwood Avenue P.O. Box 269 Luonia, WI 53036 Radel Leather Company 849 Broadway Newark, NJ 07104 Rainbow Leather Inc. 14-15 112th Strect College Point, NY 11356 Rapid Leather 11 Main Street Peabody, MA 01960 F. Rathaus and Son, Inc. 224 West 30th Street , New York, NY 10001 W.C. Reynolds Company, Inc. 30 South Allen Street New York, NY 10001 Richard Leather Co., Inc. 9 Webb Street P.O. Box 868 Salem, MA 01970 Robus Leather Corporation 4201 Wilson Avenue Madison., IN 47250 Salz Leathers, Inc. 1040 River Street P.O. Box 1840 Santa Cruz, CA 95061-1840 Sawyer Taming Company. 68 Coombs Street P.O. Box 760 Napa, CA 94559 Scholze Tannery 3000 South Broad Street, Suite B Chattanooga, TN 37405 . Moench Tanning Company P.O. Box 359 Gowanda, NY 14070 R. Neumann Leathers 66-D River Road Hudson, NH 03051 New Directions in Leather P.O. Box 2297 South Portland, ME 04106 New Jersey Tanning Co., Inc. 4 10 Frelinghuysen Avenue Newark, NJ 07114 New" Leather Corporation 2101 Ross Avenue Cincinnati, OH 45212 Nippi New York, Inc. One Bridge Plaza, Suite 250 Fort Lee, NJ 07024 Oriental King, Inc. 5 192-C Indian Trd t Industrial Pkwy. .- Norcross, GA 30071 Pan American Tanning Corp. 318 West Fulton Street Gloversville, NY 12078 MarioPa a&Sons P.O.Box 748 - Gloversville, NY 12078 W. Pearce and Brothers, Inc. 38 West 32nd Street, Suite 604 New York, NY 10001 Pell'Italia 218 W 37th Street New York, NY 10018 Pfister & Vogel Tanning Co. 1531 North Water Street P.O. Box 745 Milwaukee, WI 53201 W.B. Place & Company 368 West Summer Street Hartford, WI 53027 Prime Tanning Co., Tnc. Sullivan Street P.O. Box 713 Bzrwick, ME 03901 C.S. Raddatz Leather Company W1240 Elmwood Avenue P.O. Box 269 Luonia, WI 53036 Radel Leather Company 849 Broadway Newark, NJ 07104 Rainbow Leather Inc. 14-15 112th Street College Point, hi 11356 Rapid Leather 11 hain Street Peabody, MA 01960 F. Rathaus and Son, Inc. 224 West 30th Street , New York, NY 10001 W.C. Reynolds Company, Inc. 30 South Allen Street New York, NY 10001 Richard Leather Co., Inc. 9 Webb Street P.O. Box 868 Salem, MA 01970 Robus Leather Corporation 4201 Wilson Avenue Madison, IN 47250 Salz Leathers, Inc. 1040 Rver Street P.O. Box 1840 Santa Cruz, CA 95061-1840 Sawyer Tanning Company. 68 Coombs Street P.O. Box 760 Napa, CA 94559 Scholze Tannery 3000 South Broad Street, Suite B Chattanooga, ’I” 37405 Schwa.rz leather Co. P.O. Box 6500 400 Gotham Parkway Carlstadt, NJ 07072 Seidel Tanning Corporation 1306 East Meinecke Avenue P.O. BOX12571 Milwaukee, WI 53212 Seton Leather Company 849 Broadway Newark, NJ 071W Shrut & Asch Leather Co., Inc. 132 Ipswich Street Boston, MA 02315 \ Si-ma Leathers, hc. 50 Pocono Road P.O. Box 5249 BrookEieId, CT 06804-5249 Sirois Leather, Inc./ Wellington International, Inc. ' P.O.Box 923 Newburyport, MA 01950-5623 skinprints 122 West 26th Street New York, NY 10001 Slip-Not Belting Corporation 432 East Main Street P.O. Box 89 Kingsport, "PI 37662 Henry Sokol Leather Co., Inc. . 614 West Brown Deer Road Suite F Milwaukee, WI 53217 Milton Sokol and Company Inc. 92 Warren Street New York, NY 10007 Steinberg Bros., Inc. 23.5 W.56th Street, Suite 28M New York, NY 10019 Ralph Steinberg, Inc. P.O. Box 5249 50 Pocono Road Brookfield, CT 06804-5249 Stock Kojima American Corp. 208 W. 29th Street, Suite 501-A New York, NY 10001 Stormy Leather Ltd. 555 Eight Avenue, 11th Floor New York, NY 10018 Suncook Tanning Corporation 40 Endicott Street P.O. Box 3009 Peabody, MA 01960 Tandy Leather Company P.O. Box 791 Ft. Worth, TX 76101 Tennessee Tanning Company 915 North Atlantic Street P.O. Box 967 Tullahoma, 73-37388 Thiele Tanning Company 123 North 27th Street Milwaukee, WI 53208 Top International 303 Fifth Avenue #610 New York, NY 10016 Travel Leather Co., hc. 42 Walnut Street P.O. Box 747 Peabody, MA 01960 Twin City Leather Co., Inc. 3-15 River Street Gloversville, NY 12078 Ultimate Leather 70 Division Street Gloversville, NY 12078 Unicorn Leather Corp. Williams Way Durham, NH 03824 Virginia Oak Tannery, Inc. 149-41 14th Avenue JVhitestone, NY 11357 Schwarz leather Co. P.O. BOX6500 400 Gotham Parkway Carlstadt, NJ 07072 Seidel Tanning Corporation 1306 East Meinecke Avenue P.O. Box 12571 Milwaukee, WI 53212 Seton Leather Company 849 Broadway Newark, NJ 071M Shrut & Asch Leather Co., Inc. 132 Ipswich Street Boston, MA 02315 \ Sima Leathers, Lnc. 56Pocono Road P.O. Box 5249 BrooEeld, CT 06504-5249 Sirois Leather, hc./ Wellington International, Inc. ’ P.O. Box 923 Newbuxyport, MA 01950-5623 skinprints 122 West 26th Street New York, NY 10001 Slip-Not Belting Corporation 432 East Main Street P.O. Box 89 Kingsport, TN 37662 Henry Sokol Leather Co., Inc. 614 West Brown Deer Road Suite F Milwaukee, WI 53217 Milton Sokol and Company Inc. 92 Warren Street New York, NY 10007 Steinberg Bros., Inc. 23.5 W. 56th Street, Suite 28M New York, NY 10019 Ralph Steinberg, Inc. P.O. Box 5249 50 Pocono Road Brookfield, CT 06804-5249 Stock Kojima American Corp. 208 W. 29th Street, Suite 501-A New York, NY 10001 Stormy Leather Ltd. 555 Eight Avenue, 11th Floor New Y-ork, NY 10018 Suncook Tanning Corporation 40 Endicott Street P.O. Box 3009 Peabody, MA 01960 Tandy Leather Company P.O. Box 791 Ft. Worth, TX 76101 Tennessee Taming Company 915 North Atlantic Street P.O. Box 967 Tullahoma, TX 37388 ThieIe Tanning Company 123 North 27th Street Milwaukee, WI 53208 Top International 303 Fifth Avenue #610 New York, Ny 10016 Travel Leather Co., hc. 42 Walnut Street P.O. Box 747 Peabody, MA 01960 Twin City Leather Co., hc. 3-15 River Street Gloversville, NY 12078 Ultimate Leather 70 Division Street Gloversville, NY 12078 Unicorn Leather COT. Williams Way Durham, MH 03824 Virginia Oak Tannery, Inc. 149-41 14th Avenue Whitestone, NY 11357 Volunteer Leather Co. Genesco Park +652 Nashville, "N 37202 Warden Leathers, Inc. P.O. Box 842 Gloversville, NY 12078 Wellington Intenational, Inc./ Sirois Leather, Inc. 10 Mulliken Way P.O. Box 923 Newburyport, MA01950-5623 Westfield Tannine Comuanv*, 360 Church StieetY Westfield, PA 16950 Whitehall Leather Company 900 South Lake Street Whitehall, -MI 49461-1598 Bill Williams, Jr. Co. 3506 Cedar Springs P.O. Drawer 191407 < Dallas, Tx 75219 -> Wolverine Leathers 123 North Main Street Rockford, MI 49351 Wood and Hyde Leather Co., Inc. 68 Wood Street P.O. Box 786 Gloversville, NY 12078 World Skins- Loshen/Crystal Leather Co., Inc. 214 West 29th Street, Suite 305 New York, NY 10001 3M Company/ Protective Chemical Products Div. 3M Center, 301-E43 St. Paul, MN 55144-1000 Arcona Trading Company, Inc. 100 Evergreen Avenue Newark, NJ 07114 M. Aschheim Co., Inc. 10 High Street Boston, MA 02 110 Atlas Refinery, Inc. 142 Lockwood Street Newark, NJ 07105 Barkev International Comoration of Coinecticut 755 Unauowa Road, Room 350 Fairfield, CT 06430 BASF Corporation Coatings & Colorants Division 100 Cherry Hill Road P.O. Box 181 Parsippany, NJ 07054 Bzmcolors-Poughkeepsie, Inc. 75 North Water Street P.O. Box 29 Poughkeepsie, NY 12602 Boehme Filatex Inc. \Vatlington Road Route 11, Box 5 Reidsville, NC 27320-8662 Harland M. Braun & Co. 4010 Whiteside Street . Los Angeles, CA 90063 Harold M. Brodsky, Inc. 8618 Cheltenham Avenue P.O. Box 27069 Philadelphia, PA 19118 Buckman Laboratories, Inc. 1256 North McLean Boulevard Memphis, TN 38108 Central Research Laboratories P.O. Box 75 Red Wing, MN 55066 Chemical Coating Materials Co. 40 Little Street Belleville, NJ 07109 Chemtan Company, Inc. Hampton Road P.O. Box C Exeter, NH 03833-0050 Chicago Refrigerated Warehouse 833 W. Haines Street Chicago, I1 60622 Volunteer Leather Co. Genesco Park #652 Nashville, TN 37202 Warden Leathers, Inc. P.O. Box 842 Gloversville, NY 12078 Wellington International, hc./ Sirois Leather, Lnc. 10 Mulliken Way P.O. Box 923 Newburyport, iMA 01950-5623 Westfield Tanning Company 360 Church Street Westfield, PA 16950 Whitehall Leather Company 900 South Lake Street Whitehall, ,MI 49461-1598 Bill Williams, Jr. Co. 3506 Cedar Springs P.O.Drawer 191407 Dallas, Tx 75219 Wolverine Leathers 123 North Main Street RocHord, MI 49351 Wood and Hyde Leather Co., Inc. 68 Wood Street P.O. Box 786 GloversvilIe, NY 12078 World Skins- Loshen/Crystal Leather Co., Inc. 214 West 29th Street, Suite 305 New York, NY 10001 3M Company/ Protective Chemical Products Div. 3M Center, 301-lE-03 St. Pad, MN 55144-1000 Arcona Trading Company, Inc. 100 Evergreen Avenue Newark, NJ 07114 M. Aschheim Co., Inc. 10 High Street Boston, MA 02110 Atlas Refinery, hc. 142 Lockwood Street Newark, NJ 07105 Barkev International ComorationL of Corbecticut 755 Unauowa Road, Room 350 FairfieId, CT 06430 ' BASF Corporation Coatings & Colorants Division 100 Cherry Hill Road P.O. Box 151 Parsippany, NJ 07054 Bemcolors-Poughkeepsie, Inc. 75 North Water Street P.O. Box 29 Poughkeepsie, NY 12602 Boehme Filatex Inc. Itratlington Road Route 11, Box 5 Reidsville, NC 27320-8662 Harland M. Braun & Co. . 4010 Whiteside Street Los Angeles, CA 90063 Harold M. Brodsky, Inc. 8618 Cheltenham Avenue P.O. Box 27069 Philadelphia, PA 19118 Buckman Laboratories, Inc. 1256 North McLean Boulevard .. Memphis, TN 38108 Central Research Laboratories P.O. Box 75 Red Wing, MN 55066 Chemical Coating Materials CO. 40 Little Street Belleville, NJ 07109 Chemtan Company, Inc. Hampton Road P.O. Box C Exeter, NH 03833-0050 Chicago Refrigerated Warehouse 833 W. Haines Street Chicago, I1 60622 f Chilewich Partners 12 Water Street White Plains, hi10601 CHS Intercontinental Company P.O. Box 771027 I- 2077 South Gessner. Suite 110 Houston, Texas 77063 Peter CooDer Comorations Cameron-Brown Building 301 S. McDowell St., Suite 900 Charlotte, NC 28204-2693 Emerson Leather 816 13th Street, N.E. Hickory, NC 28601 \ Exeter Machine Co.. Inc. 309 South Water Street * Lomira, WI 53048 Fishbeck, Thompson, Can & Huber, Inc. 6090 East Fulton P.O. Box 211 Ada, MI 49301 . Fred Gruen Co., Inc. . 6310 North Port Washington Rd. P.O. Box 17287 Milwaukee, WI 53217 Hamblet & Hayes Co. Colonial Road P.O. Box 730 Salem, MA 01970 Henkel Cop Leather Chemicals Division 222 Central Street P.O. Box 1151 Saups, MA 01906 AJ. Hollander & Co., Inc. 257 Park Avenue South, Suite 12A New York, NY 10010-7304 Hollander Denver Corporation 250 East 54th Avenue P.O. Box 16146 Denver, CO 80216 Kanematsu-Gosho (U.S.A.), Inc. 333 South Hope Street Suite 2800 Los Angeles, CA 90071 Kaufmann Dietrich Enterprises Inc. 237 Albany Street Boston, MA 02118 Kirk's Suede-Life, Inc. 2501 West Fuiton Street Chicago, IL 60612 KT.M.C. Ltd. Partnership/ Koch Tanning Machinery Co. 21320 Dora1 Road Waukesha, WI 53186 Marden-Wild Corporation P.O. Box 1030 40 Salem Street S. Lynnfield, MA 01940 Marubeni American Corporation 200 E Randolph Drive, Suite 4838 Chicago, IL 60601 Metro Leather Corp. 230 West 38th Street New York, NY 10018 Mobay Chemical Corporation I 2450 Iorio Street P.O. Box 385 Union, NJ 07083 Nahe Texad, Inc. P.O. Box 1317 Pasadena, TX 77501-1317 Newon Industries Corp. One bridge Plaza, Suite 270 Fort Lee, NJ 07024 Nissho IWAI American Cop. 700 South Flower Street Suite 1900 Los Angeles, CA 90017 Nozaki American, Inc. One World Trade Center Suite 3341 New York, NY 10048 Chilewich Partners 12 Water Street White Plains, luY 10601 CHS Intercontinental Company P.O. Box 771027 2077 South Gessner, Suite 110 Houston, Texas 77063 Peter Cooper Corporations Cameron-Brown Building 301 S. McDowell St., Suite 900 Charlotte, NC 23204-2693 Emerson Leather 816 13th Street, N.E. Hickory, NC 28601 \ Exeter Machine Co., Inc. 309 South Water Street Lomira, WI 53&5 Fishbeck, Thompson, Carr & Huber, Inc. 6090 East Fulton P.O. Box 211 Ada, MI 49301 . Fred Gruen Co., Inc. I 6310 North Port Washington Rd. P.O. Box 17287 Milwaukee, WI 53217 Hamblet & Hayes Co. Colonial Road P.O. Box 730 Salem, MA 01970 Henkel Cop. Leather Chemicals Division 222 Central Street P.O. Box 1151 Saugus, MA 01906 . AJ.Hollander & Co., Inc. 257 Park Avenue South, Suite 12A New York, NY 10010-7304 Hollander Denver Corporation 250 East 54th Avenue P.O. Box 16146 Denver, CO 30216 Kanematsu-Gosho (U.S.A.), Inc. 333 South Hope Street Suite 2800 Los Angeles, CA 90071 Kaufmann Dietrich Enterprises Inc. 237 Albany Street Boston, MA 02 118 Kirk's Suede-Life, Inc. 2501 West Fulton Street Chicago, IL 60612 KT.M.C. Ltd. Partnership/ Koch Tanning Machinery Co. 21320 Dora1 Road Waukesha, WI 53186 Marden-Wild Corporation P.O. Box 1030 40 Salem Street S. LyMfield, MA 01940 bfarubeni American Corporation 200 E Randolph Drive, Suite 4838 Chicago, IL 60601 Metro Leather Corp. 230 West 38th Street New York, NY 10018 Mobay Chemical Corporation I 2450 Iorio Street P.O. Box 385 Union, NJ 07083 Nahe Texad, Inc. P.O. Box 1317 Pasadena, TX 77501-1317 Newon Industries Corp. One bridge Plaza, Suite 270 Fort Lee, NJ 07024 Nissho rWAI American Corp. 700 South Flower Street Suite 1900 Los Angeles, CA 90017 Nozaki American, Inc. One World Trade Center Suite 3341 New York, NY 10048 Occidental Chemical Corporation P.O. Box 344 Niagara Falls, NY 14302 Pacific Overseas of America, Lnc. Lincoln Plaza, Suite 174 4545 North Lincoln Boulevard OkIahoma City, OK 73105 Philadelphis Hide Brokerage Corp. 251 South 24th Street Philadelphia, PA 19103 AJ. and J.O. Pilar, Inc. 145 Chapel Street Newark NJ 07105 Pilar River Plate Corp. \ 8-10 Lister Avenue Newark, NJ 07105 Prime Leather Finishes Co. 205 South 2nd Street Milwaukee, WI 53204 . Rocke & Sons Lnc. 1 P.O. Box 2285 I 83 Pine Street Peabody, MA 01960 Rohm and Haas Com any Independence Mall est Philadelphia, PA 191054 Rohm Tech, Inc. 195 Canal Street Malden, MA 02148 J.F. Rothschild Co., Inc. 1046 East 18th Street Brooklyn, NY 11230 Salem Oil & Grease CO. 60 Grove Street P.O. Box 4468 Salem, MA 01970 Sandoz Chemical Corporation P.O. Box 18278 4000 Monroe Road Charlotte, NC 28218 Southwest Hide Company 250 South Beechwood P.O. Box 7946 Boise, ID 83709 Southwestern Trading CO. P.O. Box 7946 Houston TX 77233 Stahl USA 26 Howley Street P.O. Box 3599 Peabody, MA 01961-3599 Stockhausen Inc. 2408 Doyle Street Greensboro, NC 27406 Tannin Comoration 60 Pulaslci Street Peabody, MA 01960 Thom McAn Manufactwbg Spring Street & River Road P.O. Box 440 Wilkesboro, NC 28697 Union S ecialties, hc. 3 Mako m Hoyt Drive Newburyport,P MA 01950 United Industries 2828 S.E. 14th Avenue Portland, OR 97202 The United States Shoe Corp. One Eastwood Drive Cincinnati, OH 45227 Wayne Chemical Corp. 546 South Water Street P.O.Box 04159 Milwaukee, WI 53204 Weber and Smith, Inc. 15 Pierce Street P.O. Box 88 Reading, MA 01867 Whittemore-Wright Company, Inc. 62 Alford Street Boston, MA 02129 Occidental Chemical Corporation P.O. Box 343 Niagara Falls, NY 14302 Pacific Overseas of America, Inc. Lincoln Plaza, Suite 174 4545 North Lincoln Boulevard Oklahoma City, OK 73105 Philadelphis Hide Brokerage Corp. 251 South 24th Street Philadelphia, PA 19103 A.J. and J.O. Pilar, Inc. 135 Chapel Street Xewark NJ 07105 Pilar River PIate Corp. \ 8-10 Lister Avenue Newark, NJ 07105 Prime Leather Finishes Co. 205 South 2nd Street iMilwaukee, WI 53204 . Rocke & Sons Inc. P.O. Box 2285 83 Pine Street Peabody, MA 01960 Rohm and Haas Com any Independence Mall PPest Philadelphia, PA 19105 Rohm Tech, Inc. 195 Canal Street Malden, MA 02148 J.F. Rothschild Co., Inc. 1046 East 18th Street Brooklyn, NY 11230 Salem Oil & Grease CO. 60 Grove Street P.O. Box 4468 Salem, MA 01970 Sandoz Chemical Corporation P.O. Box 18278 4000 Monroe Road Charlotte, NC 28218 Southwest Hide Company 250 South Beechwood P.O. Box 7946 Boise, ID 83'709 Southwestern Trading Co., P.O. Box 7946 Houston TX 77233 Stahl USA 26 Howley Street P.O. Box 3599 Peabody, MA 01961-3599 Stockhausen hc. 2408 Doyle Street Greensboro, NC 27406 \ Tannin Corporation 60 Pulaslci Street Peabody, MA 01960 Thorn McAn Manufacturing Spring Street & River Road P.O.Box 440 WiTkesboro, NC 28697 Union S ecialties, Inc. 3 Makopm Hoyt Drive Newburyport, MA 01950 United Industries 2828 S.E. 14th Avenue Portland, OR 97202 The United States Shoe Cop. One Eastwood Drive Cincinnati, OH 45227 Wayne Chemical Corp. 546 South Water Street P.O. Box 04159 Milwaukee, WI 53204 Weber and Smith, Inc. 15 Pierce Street P.O. Box 88 Reading, MA 01867 mittemore-Wright Company, Inc. 62 Alford Street Boston, MA 02129 L I World Trading Inc. 121 Spencer Plain Road Old Saybrook, CT 06475 Southwest Hide Co. 1134 W. Lincoln Phoenix, AZ 85001 Golden Wool Company 3001-T Sierra Pine Avenue Los Angeles, CA 90023 Napa Glove Company, Inc. Dept. T, P.O. Box 509 Napa, CA 94558 Colorado Tanning & Fur Dressing Company 1793 S. Broadway , Denver, CO 80904 American Blue Co., Inc. 236-T Liberty Street Wilmington, DE 19805 National Rawhide Mfg. CO. ’ 1464 Webster Avenue Chicago, IL 60614 \ Middlesboro Taming Co. 1200-T Shermer Road Northbrook, IL 60065 Bonita Tanning Inc. Hwv 99 P.O. Box 309 Bonita, LA Wilton Tanning Co., Inc. Rtes 2 & 4 P.O. Box 204 East Wilton, ME 04234 N.KL. Tanning Inc. 72 Main Saco, ME 04072 Speco, Inc. 61 Rantoul St. Beverly, MA Drew.Tanning of Brockton, Inc. P.O. Box 1396 Brockton, MA 02403 Brindis Tanning Co. 59 Washington St. Haverhill, MA 01832 Chic Leather Co., Inc. 84-T Wingate St. Haverhill, MA 01832 Essex Shoe Trimming Co. 57-T Washington St. Haverhill, ;"\/€A01532 Alw Leather Co., Inc. P.6. Box 255 Peabody, &LA 01960 Begs & Cobb Corp. 139-T LyIlnfield St. Peabody, MA 01960 Bob-Kat Leather Co., Inc. R166 Main St. Peabody, MA 01960 Fermon Leather Co. 11-27 Walnut St. Peabody, MA 01960 Masino Leather Co., Inc. P.O. Box 407 Peabody, MA 01960 Matz, N.H. Leather Co P.O. Box 488 Peabody, MA 01960 Strauss Tanning Co. 145-T Lowell St. P.O. Box 486 Peabody, MA 01960 Tan-Rite Leather Cop. 39-T Wallis St. Peabody, MA 01960 Foster Leather Co., Inc. 51-T CudSt. Salem, MA 01970 Mason Tanning Co., Inc. 4 Water St. Salem, MA 01970 World Trading Inc. 121 Spencer Plain Road Old Saybrook, CT 06475 Southwest Hide Co. 1134 W. Lincoln Phoenix, AZ 85001 Golden Wool Company 3001-T Sierra Pine Avenue Los Angeles, CA 90023 Napa Glove Company, Inc. Dept. T, P.O. Box 509 Napa, CA 94558 Colorado Tanning & Fur Dressing Company 1793 S. Broadway \ Denver, CO 80904 American Blue Co., Inc. 236-T Liberty Street Wilmin,oton, DE 19805 National Rawhide Mfg. CO. ’ 1464 Webster Avenue Chicago, IL 60614 Mddlesboro Tanning Co. 1200-T Shermer Road Northbrook, IL 60065 Bonita Tanning Inc. Hwy 99 P.O. Box 309 Bonita, LA Wilton Tanning Co., he. Rtes 2 & 4 P.O. Box 204 East Wilton, ME 04234 NKL. Tanning Inc. 72 Main Saco, ME 04072 Speco, Inc. 61 Rantoul St. Beverly, MA Drew Tanning of Brockton, Inc. P.O. Box 1396 Brockton, MA 02403 Brindis Tanning CO. 59 Washington St. Haverhill, MA 01832 Chic Leather Co., Inc. 84-T Wingate St. Haverhill, MA 01832 Essex Shoe Trimming CO. 57-T Washington St. Haverhill, MA 01832 Alg Leather Co., Inc. P.O. Box 255 Peabody, MA 01960 Bqgs & Cobb Corp. 139-T Lvnnfield St. Peabodi, MA 01960 Bob-Kat Lgather Co., Inc. R166 Main St. Peabody, MA 01960 Fermon Leather Co. . 11-27 Walnut St. Peabody, MA 01960 Masino Leather Co., Inc. P.O. Box 407 Peabody, MA 01960 Matz, N.H. Leather Co P.O. Box 488 Peabody, MA 01960 Strauss TanniTlg Co. 145-TLowell St. P.O. Box 486 Peabody, MA 01960 Tan-Rite Leather Corp. 39-T Wallis St. Peabody, MA 01960 Foster Leather Co., Inc. 51-T Canal St. SaIem, MA 01970 Mason Tanning Co., Inc. 4 Water St. Salem, MA 01970 -. CHP Inc. 3717-T L St. Omaha, NE 63510 Cayadutta Tanning Co. 98 Harrison St. Gloversville, NY 12078 Hochauster, Walter Leather Co., Inc. 2335-T Boston Post Road P.O.Box 910 Larchmont, NY 10538 Eastern Tanning Co., Inc. 27-01 Bridge Plaza, N Long Island City, NY 11101 Marshall Leather Finishing Co., Inc. , 43-45 Wooster St. New York, NY 10013 Stem, Paul N., Leather Co., Inc. 459-T W 15 St. New York, NY 10004 Vista Resources, Inc. 350-T 5th Ave New York, NY 10118 Muir & McDonald Co. 505-T S.W. Levens P.O. Box 136 Dallas, OR 97338 Lawrence, Geo., Co. 1435-TN.W. Northup Portland, OR 97209 Clearfield Taxidermy 603-605 H~IIIM~St. , P.O.Box870 Clearfield, PA 16830 Brown, Wm C. Leather Co. PhiladelpI7O0 TuliK ia,St. PA 19125 Fouke Co. 8100-T White Horse Rd. Greenville, SC 29605 -. Armira Co. Hwy 18 N P.O. Box 192 Bolivar, TN 38008 Mid-Tem Tanning Co., Inc. Dept T Industrial Pkwy P.O. Box 577 Shelbyville, ’TX 37160 Hollander Fort Worth Corp. P.O. Box 4483 Fort Worth, TX 76106 Nelson & Sons, hc. 625-T Humble Ave., P.O. Box 2076 San Antonio, TX 78297 Fox Valley Leathers, Inc. 633 W Center St. North Salt Lake, UT 85054 Drollinger, J & G Associates 185 N.V.A. Vernal, UT 84078 Quill Cedar Tanning Co. 3 922-T 88th St. NE. Marysville, WA 98270 Berlin Glove Co. 150-T W Franklin St., P.O. Box 120 Berlin, Wi 54923 Berlin Tanning & Mfg., Cl. 235-T S. Wisconsin St. Berlin, WI 54923 Bellevue Curing & Bluing Inc. 1818-T N Water St. Milwaukee, WI 53202 Law Tanning Co. 401-T S. 7th St. Milwaukee, WI 53204 Oshkosh Tanning Co. 612-T N. Broadway Milwaukee, WI 53202 -. CHP Inc. 3717-T L St. Omaha, NE 63510 Cayadutta Tanning Co. 98 Harrison St. Gloversville, NY 12078 Hochauster, Walter Leather Co., Inc. 2335-T Boston Post Road P.O. Box 910 Larchmont, NY 10538 Eastern Tanning Co., Inc. 27-01 Bridge Plaza, N Long Island City, NY 11101 Marshall Leather Finishing Co., Inc. . 43-45 Wooster St. New York, NY 10013 Stem, Paul N., Leather Co., Inc. 459-T W 15 St. New York, NY 10004 Vista Resources, Inc. 350-T 5th Ave ?. , New York, NY 10118 MUir & McDonald Co. 505-T S.W.Levens P.O. Box 136 Dallas, OR 97338 Lawrence, Geo., Co. 1435-TN.W. Northup Portland, OR 97209 Clearfield Taxidermy 603-605 H~Jux~~St. P.O. Box 870 ’ Clearfield, PA 16830 Brown, Wm C. Leather Co. PhiladelpI7O0 TuliE ia,St- PA 19125 Fouke Co. 8100-T White Horse Rd. Greenville, SC 29605 Armira Co. Hwy 18 N , P.O.Box 192 Bolivar, TN 38005 Mid-Term Tanning Co., Inc. Dept T Industrial Pkwy P.O. Box 577 Shelbyville, TzIj 37160 Hollander Fort Worth Corp. P.O. Box 4453 Fort Worth, TX 76106 Nelson & Sons. Inc. 625-T Humble ‘Ave., P.O. Box 2076 San Antonio, TX 78297 Fox Valley Leathers, Inc. 633 W Center St. North Salt Lake, UT 85054 Drollinger, J & G Associates , 185 N.V.A. Vernal, UT 84078 Quill Cedar Tanning Co. 3922-T 88th St. N.E. Maxysville, WA 98270 Berlin Glove Co. 150-T W Franktin St., P.O. Box 120 Berlin, WI 54923 Berlin Tanning & Mfg., Cl. 235-T S. Wisconsin St. Berlin, WI 54923 Bellevue Curing & Bluing Inc. 1818-T N Water St. Milwaukee, WI 53202 Law Tanning Co. 401-T S. 7th St. Milwaukee, WI 53204 Oshkosh Tanning Co. 612-T N. Broadway Milwaukee, WI 53202 n I APPENDIX C Letters of 1/11/90 an( 1/23/90 Hepworth to Wismer, MRS, R,: Tanneries as potential users of Cr+++,and Recommendation to Wismer that he ask for a change in scope of project to replace Task 5 (Pyrometallurgy) with Task 4A (extension of hydrometallurgical studies with emphasis on concentration of chromium solutions). d P , APPENDIX C Letters of 1/11/90 and 1/23/90 Hepworth to Wismer, MRS, Re: Tanneries as potential users of Cr+++,and Recommendation to Wismer that he ask for a change in scope of project to replace Task 5 (Pyrometallurgy) with Task 4A (extension of hydrometallurgical studies with emphasis on concentration of chromium solutions). I.....- . . UNIVE3Si7 OF MINNESOTA Mineral Fiescurcis Research Cmtsr 56 Ezst Eiver Ecad Minneicciis, Minnescta %L5502C5 Copy to Ms. Julie MacKenzie 1/23/90 January 11, 1990 (with P. S. of 1/12/90) Mr. Michael Wismer MRS 2430 Rose Place Roseville, MN 55113 Dear Mike : This letter summarizes ur con rsation of t-rtaj with Ter Foecke of MNTAP. We discussed the desireability of' continuing the present hydrometallurgical studies on the purified chromium solutions produced via solvent extraction to produce a more concentrated product. This product should be more economical to transport to secondary refiners than .the 2 gram per liter solutions we have been purifying. This concentration step could either be via a high loading density of chromium.on ion exchange resins which would then be stripped with lower values of aqueous, or alternatively via hydroxide precipitation. Barren solutions from either approach 'should be low enough in' heavy metals - concentration to be suitable for discharge. We discussed'potential companies which might be interested in trivalent chromium whether in solid or liquid form. Mr. McGaa was going to rnview his contact in Milwaukee which supplies a local tannery, 'and Mr. Foecke mentioned another potential market. We agreed that Ms. MacKenzie should be contacted to request approval for a change ' in scope of the remaining tasks to substitute the continuing hydrometallurgical study discussed in the second paragraph of this letter' for the originally proposed pyrometallurgical study. Although we toured- the pyrometallurgical facilities here, we agreed that this latter approach is not compatible with the 'permit for MRS. If a pyrometallurgical solution to sludges is required, then the company INMETCO could be a potential one for receipt and treatment of these residues. . .- Would you plezse take the necessarv steus to secure amroval for a chance in scoDe of our work Dlan? Thank you. Sincerely yours , Malcolm T. HeFworth Professor, Metallurgical Engineering copy: Terry Foecke, MNTAP J McGaz, WC P. Babccck, MRRC 11/ 12/ 9 0 P. S. This nailed-version 'of the faxed letter of 11/11/90 corrects two typographic errors. Since writing the original letter, Mr. Jchn McGaa called me with more information about his Contacts. The Milwaukee company is Wayne Chemical Attn. Judd (412) 278-8844. He also has information on TwinBernard City Tanning and Blue Side Tanning of St. Joseph, Mo. I told him to get in touch with you directly with his information. Essentially he reports that tanneries typically use 1 to 2 grams per liter Of chromium solutions with limits of of impurities of heavy metals in the tanning solutions as follows: cu 7PPm Ni lOppm Pb 1PPm These tanneries' receive reduced chromate solutions -from several suppliers including Wayne Chemical. The latter reduces sodium chromate solutions with sugar and added acid to produce and ship 10 to 20 percent trivalent chromium solutions which are diluted to the 1-2 gram per liter level by the tanneries. Certification that the impurity levels are significantly below the above limits would be required for the MRS treated chromium streams to be acceptable. One expects that it'would be necessary to work with a secondary refiner such zs Wayne Chemical, since they have the necessary credibility and could make the certification. UNIVE3SiTY OF MINNESOTA Mineral Eescurczs Research Cantsf ;* PNlN CmES ,o =zst- Ever Ecad Minneacoiis. Minnesota SGZ-0255 (6i.2) 625-33e WX"1 0 5T6 2953 Copy to Ms. Julie MacRenzie 1/23/90 January 11, 1990 (with P. S. of 1/12/90) Mr. Michael Wismer MRS 2430 Rose Place Roseville, MN 55113 Dear Mike : This letter summarizes our conversation of today with Terry Foecke of MNTAP. We discussed the desireability of' continuing the present hydrometallurgical studies on the purified chromium solutions produced via solvent extraction to produce a more concentrated product. This product should be more economical to transport to secondary refiners than ,the 2 gram per liter solutions we have been purifying. This concentration step could either be via a high loading density of chromium.on ion exchange resins which would then be stripped with lower valumes of aqueous, or alternatively via hydroxide precipitation. Barren solutions from either approach 'should be low enough in' heavy metals - concentration to be suitable for discharge. We discussed 'potential companies which might be interested in trivalent chromium whether in solid or liquid form. Mr. McGaa was going to rzview his contact in Milwaukee which supplies a local tannery, -and Mr. Foecke mentioned another potential market. We agreed that Ms. MacXenzie should be contacted to request approval for a change in scope of the remaining tasks to substitute the continuing hydrometallurgical study discussed in the second paragraph of this letter' for the originally proposed pyrometallurgical study. Although we toured- the pyrometallurgical facilities here, we agreed that this latter approach is not compatible with the 'permit for MRS. If a pyrometallurgical solution to sludges is required, then the company INMETCO could be a potential one for receipt and treatment of these residues. . .- Would you Dlezse take the necessarv steDs to secure atmroval for a chancre in scooe of our work Dlan? Thank you. Sincerely yours , Malcolm T. Hepworth Professor, Metallurgical Engineering copy: Terry Foecke, MNTAP J McGae, MRRC P. Babcock, MRRC 11/ 12/ 9 0 P. S. This nailed-version of the faxed letter of l-l/ll/gO corrects two typographic errors. Since writing the original letter, Mr. John McGaa called me with more information about his contacts. The Milwaukee company is Wayne Chemical Attn. Bernard Judd (412) 278-8844. He also has information on Tvin City Tanning and Blue Side Tanning of St. Joseph, Mo. I told him to get in touch with you directly with his information. Essentially he reports that tanneries typically use 1 to 2 grams per liter of chromium solutions with limits of of impurities of heavy metals in the tanning solutions as follows: cu 7PPm Ni lOppm Pb 1PPm Fe 40ppm. This information confirms that the degree of purification that McGaa has achieved in his thesis work is well within the limits required for acceptable tanning quality. These tanneries’ receive reduced chromate solutions _from several suppliers including Wayne Chemical. The latter reduces sodium chromate solutions with sugar and added acid to produce and ship 10 to 20 percent trivalent chromium solutions which are diluted to the 1-2 gram per liter level by the tanneries. Certification that the impurity levels are significantly below the above limits would be required for the MRS treated chromium streams to be acceptable. One expects that it’would be necessary to work with a secondary refiner such as Wayne Chemical, since they have the necessary credibility and could make the certification. UNIVERSITY OF MINNESOTA Mineral Resources Research Center TWIN CITIES 56 East River Road Minneapolis, Minnesota 53455-0205 (6 12) 625-3344 Fax: (612) 625-1882 January 23, 1990 Mr. Michael Wismer Metro Recovery Systems 2430 Rose Place Roseville, MN 55113 Dear Mike: Ms. MzcKenzie called me todzy.in response to a copy of the letter I sent you of January 11, 1990. She indicated a chancre in scoDe of the project rewires vou to contact her in writina addressina the several Tasks in our orisinal DroDosal. The purpose of this letter is to assist you in preparing that request. To date Tasks 1-3 are complete as reported to the Minnesota Office of Waste Managernent (MOWM) in. my prior report. Task 4 is about to be reported (You have a draft copy.) This . report will be issued to you in the first week of February for your examination and transmittal to MOWN. In that report we have a section on ItFuture Studiestt, which proposes that the scope of . the investigation be changed as follows: Task 5 addressed the question of pyrometallurgical treatment of plating waste sludges which are produced by hydroxide precipitation of aqueous plating solutions. Based upon samples you sent us, we found that there was about 2 percent by weight chromium present in these sludges which had been precipitated by lime additions presumably to sulfate solutions. In consequence, these sludges are primarily gypsum with a resulting high sulfur content. Pyrometallurgical treatment of these sludges, as you indicated earlier and now confirmed by this information, is therefore not compatible with your operations at MRS. As an alternative your inhouse treatment, I have made contact with the firm INMETCO through their Technical Manager, Mr. John Oneska. He indicated that they are prepared to treat a wide range of sludges including those you currently produce with low chroinium content. I propose, therefore, that Task 5 should be replaced with an expanded Task 4 (Task 4A). This Task 4A will emphasize concentration of chromium from the purified solutions. Task 4A Backaround: Currently in our second report, which is about to be issued, we show that a highly purified solution of chromium can be obtained by solvent extraction. Impurities are I I removed to an organic phase. The resulting aqueous phase (raffinate) is not upgraded in chromium content because chrcmium is not extracted to the organic phase. This raffinate continues to be at the original concentration which is about 2 grams per liter. The bulk of the raffinate is therefore water, which would not be economical to ship to a secondary refiner for resale. Promsed Extension: I propose that the following tests be conducted on the purified chromium raf f inate: Examine concentration methods including: *evaporation/crystallization; *precipitation; *loading of the chromiun solutions on ion exchange resins. These three approaches should be examined and compared with respect to their technical feasibility and economics for shipment for secondary refining to produce a marketable chromium product for the tanning industry. This latter industry is the primary user of trivalent chromium I chemicals as determeined by our survey. We would also like to explore- the variation of organic- to-aqueous loading ratios and the effect of reaction kinetics to minimize chromium extraction while maximizing the extraction of the other heavy metallic constituents. Task 6 would follow Task 4A. Task 6 would exclude pyrometallurgical/hydrometallurgical comparisons but would emphasize the implementation of the hydrometallurgical process of solvent extraction followed by the appropriate concentration method developed in Task 4A. Task 4A would be completed during the same schedule oricjinally planned for Task 5. I would appreciate your recasting this letter into appropriate language for the consideration of Ms. MacKenzie. I suggest that you communicate with her directly and let me know at your earliest convenience regarding the outcome. Thank you. Sincerely yours, Malcolm T. Hepworth Professor, Metallurgical Engineering UNIVERSITY OF MINNESOTA Mineral Resources Research Center TWIN CITIES 56 East River Road Minneapolis, Minnesota 533550205 (612) 625-3344 Fax: (612) 625-1882 January 23, 1990 Mr. Michael Wismer Metro Recovery Systems 2430 Rose Place Roseville, MN 55113 Dear Mike: Ms. MacKenzie called me today-in res2onse to a copy of the letter I sent you of January 11, 1990. She indicated a chancre in scooe ' of the project rewires vou to contact her in writincr addressincr the several Tasks in our orisinal proDosal. The purpose of this letter is to assist you in preparing that request. To date Tasks 1-3 are complete as reported to the Minnesota Office of Waste Management (MOWM) in. my prior report. Task 4 is about to be reported (You have a draft copy.) This report will be issued to you in the first week of February for your examination and transmittal to MOWN. In that report we have a section on "Future Studiestt, which proposes that the scope of . the investigation be changed as follows: Task 5 addressed the question of pyrometallurgical treatment of plating waste sludges which are produced by hydroxide precipitation of aqueous plating solutions. Based upon samples you sent us, we found that there was about 2 percent by weight chromium present in these sludges which had been precipitated by lime additions presumably to sulfate solutions. In consequence, these sludges are primarily gypsum with a resulting high sulfur content. Pyrometallurgical treatment of these sludges, as you indicated earlier and now confirmed by this information, is therefore not compatible with your operations at MRS. As an alternative your inhouse treatment, I have made contact with the firm INMETCO through their Technical Manager, Mr. John Oneska. He indicated that they are prepared to treat a wide range of sludges including those you currently produce with low chromium content. I propose, therefore, that Task 5 should be replaced with an expanded Task 4 (Task 4A). This Task 4A will enphasize concentration of chromium from the purified solutions. Task 4A Backaround: Currently in our second report, which is about to be issued, we show that a highly purified solution of chromium can be obtained by solvent extraction. Impurities are I I removed to an organic phase. The resulting aqueous phase (raffinate) is not upgraded in chromium content because chromium is not extracted to the organic phase. This raffinate continues to be at the original concentration which is about 2 grams per liter. The bulk of the raffinate is therefore water, which would not be economical to ship to a secondary refiner for resale. Promsed Extension: I propose that the following tests be conducted on the purified chromium raf f inate: Examine concentration methods including: *evaporation/crystallization; *precipitation; *loading of the chromium solutions on ion exchange resins. These three approaches should be examined and compared with respect to their technical feasibility and economics for shipment for secondary refining to produce a marketable chromium product for the tanning industry, This latter industry is the primary user of trivalent chromium. chemicals as determeined by our survey. We would also like to explore-the variation of organic- to-aqueous loading ratios and the effect of reaction kinetics to minimize chromium extraction while maximizing the extraction of the other heavy metallic constituents. Task 6 would follow Task 4A. Task 6 would exclude pyrometallurgical/hydrometallurgical comparisons but would emphasize the implementation of the hydrometallurgical process of solvent extraction followed by the appropriate concentration method developed in Task 4A. Task 4A would be completed during the same schedule oric$.nally planned for Task 5. I would appreciate your recasting this letter into appropriate language for the consideration of Ms. MacKenzie. I suggest that YOU communicate with her directly and let me know at your earliest convenience regarding the outcome. Thank you. Sincerely yours, Malcolm T. Hepworth Professor, Metallurgical Engineering APPENDIX D Proposed Change in Scope of Project: Task 5 change I APPENDIX D Proposed Change in Scope of Project: Task 5 change X. , SYSTEMS As we disc2sss.d ezrlier, ETRC) RZCOVZX SYSTEES prcsoses to chzrqe the scse of its Grazts Proszam project, "Zduction of Chromium PLazinc Wasizec". The chl,ance is being r .eq:ested, as a result of in2ormation uxovere2 Curine; the cours e cf o~r project . Specifictlly, we are requestins the replacement or' Tzsk 5, Liwestlgatior, of pyrometallurgical methods of ckomium recove-y, witk a new Task A&. the new area of work will focus on mcre intensive investigation of the hydrometallsrgical recovsry methoe izvestigated in Tzsk 4. There are tk-se primary reasons for our rquest. First, in December, 1985 we fount! a commercii1 pyrometalluzgiczl processor of chromium-containizg sludges (Inmetco, Ellwood 3- LL- City, FA) . I,- LAlc time our project was conceived wt were not aware that this apcoach was being developed mywhere. The intact of this part of our project was to simply detsrmine .C Li, in2ec6, F?-rcmetallurSry was a feasible recove-ry crocess znd to Lr~veszi~zteoptimal furnace operzting conditions. 'Sinct I-meccc is applying this process on a conunsrcial scale, i'i is obviousl:. a fezsible process. We believe fwking for our project c=n be betttr applrt2 elsewhere. Sacs~l,the hyikomet2lxrgicel zpprr~achusee in Tzsk 4 acpears co heve good potertitl as a recovery msthcl basel on reszlzs reported to ycur cffics in our February 1, 1990 prqress zeS3rt. We fe~lthat fslIr,r:izic-ul; this wcrk witk th: describe2 ir, oGr F-fter you heva hac 2 ctace to review the enclosec', chnge-of- scme submission, please contect me wizh any questions or cohents that you mey have. Very truly yours, Michael W. Wismer Tec-'Lnical Mmtger Mww/ yo Enclosure SYSTEMS rls we disctlssac', ezrlier, MZTRO R5CC)VEX SYSTEES prc;oses to chase the scsse of its Grants Frogrm project, "fiduction cf Chromium P1azFnc Wasces" . The chtnge is being reqr~este~5zs a result of in2cmzcion mxovezeC during the course cl ow proj ect . Specifically, we are requestins the reglacement of Tzsk 5, Lrwestigatior, ,of pyrometallurgiczl methods of ckomium recovery, wits a r,ew Ttsk AJ-. the new area of work will focus on mcre intensive investigation of the hydrometallxrsical recovery methoe iavestigated in Task 4. There are tkee primary reasons for OUT rquest. First, in December, 1985 we fomd. B commercial pyrometallurgicdl processor of ckomium- contair,izg sludges (Inmetco, Ellwood 7- LL- City, FA) . I-- LAlc time our prcrject was conceivect we were not aware thzt this apgroach was being developed mywhere. The intect of this part of OUT project was to simply determine i' -I, inded, p>-rametallu=g was a feasible recove-ry process md to Lrrvestisate optimzl furnece operzt-ing conditions. Sinct 1-meccc is applyins this process on a commercial scale, it is obvicusl~~2 fezsible procsss. We believe fwking for our project CZI be jettir a??lis< elsewhere. SSCSE~,the hyC~omet2llxrgic2lmprach usee in Task 4 acpears TO hzve good poter-tid 2s a recovery metho< bzs& on reszlzs reported to ycur cr'fics- -- in OCZ FeSruary I, 1940 prosress re?:ort. We fe~lthat zs--r,r:i_r,~-u~this work witk tkt: describet ir, our 1 , a of contzmintzc metals. Concencratics of this phzse is - necessary for econcmical recovery OF a commercial --scale. -n tedi:icn, we propose to further imesticate the ezrert of varyizj or~eric-to - aquems ratios cr, the extracticn process . This would help us refine the procsss and maximize recovery ~f ckromium. After you hzve had. a ctzrlce to review the enclosed change-of- scope submission, please contzct me yith any questions or commezts that you may have. Very truly yours, Michzel W. Whiner Tec.hnical Mznzger m/yo Enclosure ,- Talc 4A - RecLsient will plan an2 ccneuc: aeeitional labcratory sheker tests or, tsical solutions ieentified in Task 1 to investigate organic phase-to-aweous phase loadizg ratios ad the el‘fect or’ reactior, kinetics for improved sepzratior, or’ metallic impurities from the chromium- contahing pkzse. Recipient will report results of each trial giving metal concentrations found in the organic and aqueous phases, respectively 2s well 2s perform a mass balance between phases. Reci2ient will undertake investigation of three metho& of concentration of the chromiw-containing aqueous phase. These methods are : 1) evaporationlrecrystzl~izatioc; 2) precipitzticn; 2nd 3) ior, exchange. Recipient will report results of tests from the three methoes inclueing level of concentretior, echieved, effects of cmcentraticn on impaity level me effects of coccentration on the -:sc,hical feasibility z.xc? economics for shipment of the recovered materials to 2 secondary refiner to proiiuce a marketzble proeucz tc indtlstries Fi!elztFfied in T+ck 2. Lebcr: $1,106.00 . Recigient will comglete Tzsk 42- within 48 weeks of the effective date of this agreemext provided ap~rovalof the ckrmge of scoge request is received. by Fkbrutry 28, 1990. If aFproval is receive6 after that dite; ReciBient will complete Task 4A in (48 f X) weeks, where X equzls the number af weeks mgroval is grznteC afcer Februay 28, 1,090. Tzsk 5 is excludetf. Recipient will complete Task 6 within (50 f X) weeks of the effective dzce of this tgreament. Recipier,~will ccnplete Ttsk 7 as 2etziled in ACzzcPdieEt B to this as’reament or X weeks thereafcor if apgrovzl to the ckm~eof sc~_ceis crtrted after February 28, 1990. Task drl - RecF_=ientwill plan and. ccr,chcz ac2Zitional labcratory shzksr tests OR t,qical solutions icleztified iE Task 1 to investigate organic phase-to-aqueous phase loadiag ratios znc! the effect or’ reaction kinetics for improved separatior, or’ metallic impurities from the chromium- containing phase. Recipiezt will report results of each trial giving metzl concentrations found in the orgvlic w-2 aweous phases, respectively ES well 2s perforin a mass bzlvlce between phases. Reci2Fenc will undertake investigation of three methoes of concentration of the chromic..- containing aqueous phase. These methods are : I) evaporation/recrystaIlizatior,; 2) precipitation; end 3) ior, exchange. Recipient will report results of tests from the three methoes inclu6iq level of concentretion echieved, effects of cmcentraticn on impmity level a-ci?effeczs of coccentration on the .tec,hniczl feasibility zi..i.c! economics for shipment of the recovered materials to a seconda-T refiner to proeuci a marketble pro&x~:tc Fckstries iCenEifie2 i?-Tesk 2. . , LeScr: $1,106.00 . Recipiezt will comglete Task 42- within 48 weeks of the effective date of this agreement provided ap~rovzlof the chznge of scope request is received by Februzry 28, 1990. If a9provzl is received zfter that date; Recipient will complete Task AS? i~ (48 t X) weeks, where X equzls the number of weeks approvz1 is grate6 ef-ler Februz,ry 28, 1990. Task 5 is excluCiec2. Recipient will complete Task 6 withix (50 t X) weeks of the effective dace 02 this egreament. RccLpiext will complete Task 7 es &t+iled in ACiXcPfie,n,t B to this qzea,me~?tor X weeks thereafter-. if z~provalto the c,LI_z~ceof scc_ce is s=Z!?Ce2 2ft.e~resrrrzry 28, 1990. APPENDIX E Estimate of Capital Costs APPENDIX E Estimate of Capital Cost5 Amend& E Capital expenditure for a plant operating at 90,000 gallons per month: Equipment Estimates Cost Extraction Circuit $ 55,000 Holding Tank 12,000 Sludge Thickener 12,000 Precipitation Reactor 6,000 Membrane Filter Press 85,000 Pumps, Controls, etc. 15,000 Ventilation 15.000 Total $200,000 Other Installation (@ 20 9% of Equipment) $ 40,000 Engineering 30,000 Contingency -30.000 Total Capital Costs $300,000. Appendix E Capital expenditure for a plant operating at 90,000 gallons per month: Equipment Estimates Cost Extraction Circuit $ 55,000 Holding Tank 12,000 Sludge Thickener 12,000 Precipitation Reactor 6,000 Membrane Filter Press 85,000 Pumps, Controls, etc. 15,000 Ventilation 15,000 Total $200,000 Other Installation (@ 20 % of Equipment) $ 40,000 Engineering 30,000 Contingency . 30.00Q Total Capital Costs $300,000, .