i i -1 • .1 a WQ» QSQ80-OOP30 EVALUATION ^"^ — 1 OF 1 n CHLORSNE/C^SLGRiDE BASED PROCESSES OBES
FIWAL REPORT
?3 Tf «3 G? THS 7- '1 V, CfiERGV, KSfiESMSD RESOURCES, CAMA0A
OSS FILE NUIS3ER : 15SQ23«0«-9130
DSS CONTRACT SERIAL KUKESB : OSCSMXKSO
••••'I P CANMET PROJECT NUMBER : 3S5-102
CANMET SGtENTiF.'C AUTHORITY : aiR. W.A, GOW 1 i i PROJECT NO. 9309 MINERALS DIVISION EVALUATION OF CHLORINE' OSIDE 8ASED PROCESSES FOR t yjJUM ORES
Work on this project was conducted under the auspices of the Canada Centre for Mineral and Energy Technology, Department of Energy, Mines and Resources, Canada.
ISS File Number 15 SQ 23440-9-9130 DSS Contract Serial Number OSOSO-00030 CANMET Process Number 335-102 CANMET Scientific Authority Mr. W.A. GOM
, - - , . I II-M. I AI.
Project No. 9309 CE Lummus November 1980 Minerals Division LU^MUS
IHDEX
1.0 INTRODUCTION
2.0 OBJECTIVES OF STUDY
3.0 SUMMARY 4.0 CONCLUSIONS AND RECOK-SENDATIONS 5.0 STUDY CRITERIA 6.0 PROCESS FOR LOW GRADE ORE
6.1 Description 6.2 Basis for Capital Cost Estimate €.3 Capital Cost Estimate 6.5 Sunjaary of Operatihq Cost Estimate I • g.6 Detailed Operating Cost Estimate 6.7 Discussion
7.0 PROCESS FOR HIGH GRADE ORE
7.1 Description 7.2 Basis for Capital Cost Estimate 7.3 Capital Cost Estimate 7.4 Basis for Operating Cost Estimate 7.5 Summary of Operating Cost Estimate 7.6 Detailed Operating Cost Estimate 7.7 Discussion APPENDIX I Drawings M LUMMU3
1.0 INTRODUCTION The CE Lunwus Minerals Division was cosraissioned by The Department of Supply and Services to evaluate "Chlorine/Chloride Based Processes for Uranium Ores". The processes are designed to resove substantially all radioactive constituents from the ores to render the waste products harmless. CE Luse-us Minerals Division engineers followed the general outline contained 1n their proposal Ho. 8-981S. Experimental work carried out at the CANKET laboratories of the Department of Energy, Nines and Resources in Ottawa was used as a basis for the evaluation. At a meeting between CASKET engineers and scientists and Lunraus engineers on May 27, 1980 agreement was reached on the processes to be Investigated and CAHKET provided Lunsmis with technical literature and laboratory data. Two processes ware selected, one for a typical low grada ore (2 1b. U30g/ton ore) and one for a high grade ore (fO lbs UiQa oer tan). For the Iwi ersfe ora 5 hv&ochlcric 8cid leaching process was chosen. Tor high grads ere, a more coraplex process. Including gasecas chiorinatica, s?as selected. A second seating was held to present Lurssus1 preliminary process flew diagrams and to incorporate consents frasi CANHET scientists and engineers. Hhen the process flow diagrams were completed, they were used to generate major equipment specifications, utility diagrams and plot plans for esch process. Capital cost estimates were compiled from Information obtained from vendors for the specified equipment. The building cost estimates and the piping, electrical and instrumentation costs were developed from the plant layout. A more detailed description of the basis for the capital cost estimates Is given in Sections 6.2 and 7.2. Utility diagrams and mass balances were used for estimating utilities and consumables. A more detailed description of the basis for the operating cost estimates 1s given in Sections 6.4 and 7.4. LUMMUS
2.0 OBJECTIVES OF STUDY Concern over add drainage and radionucleide dissolution problems associated with uranium tailings disposal has preempted Investigations into improved methods of Isolating uranium, thorium and radium from tailings. Several processes to overcome these problems and produce tailings more suitable for disposal have been proposed. The primary purpose of this study MSS to develop order of magnitude capital and operating costs for two processes now being considered by CAHMET to reduce the radioactive content of mill tailings. The cost information is Intended to assist CANHET 1n selecting areas deserving further study. LUMMUS
3.0 SUGARY An evaluation of the capital and operating costs of two plants using chlorine/chlorida technology to produce yellowcake from uranium ores has been made. The results are given below: Ore Grade Low High 1)305 Content of Ore, lbs/ton 2.0 50 Ore Input, tons/day 5.200 200 H^OQ Production: lbs/day 10,000 10,000 lbs/year 3,300,000 3,300,000 Process Used Hydrochloric Chlorination Acid Leach and Hydrochloric Acid Leach Direct Capital Cost $ 138,800.000 67,000,000 Direct Capital Cost, A? aa ?n •sn Direct Operating Cost: S/year 22,540,000 14,050,000 S/ton ore 13.13 213.00 i S/lb U308 6.83 4.26 ^SHI IM LUMMUS
4.0 CONCLUSIONS AND RECOMMEHDATIOSS 4.1 Low Grade Or3 It hss been demonstrated that the hydrochloric acid leaching process will extract uranium, thorium and radium to meet the environmental criteria of 15 picocuries (pCi) per gran in the leach residue wastes. Sulphuric acid 1s required to regenerate hydrochloric acid from spent leach liquor. For ores containing pyrite, the sulphuric add can be produced on site by floating the pyrite and roasting it. By removing the pyrite, formation of sulphuric acid 1n the tailings 1s prevented and long term lime treatment of tailings effluents 1s not necessary. High extraction of uranium, in the order of 98%, 1s possible. Before considsring a conmercial hydrochloric acid leach plant for low grade uranium ores it would be necessary to operate an integrated fi-ilnf" n'i ant 4*n HpkuaJ/in ali W ** * "~" """" a cost estimate. In order to achieve a wall designed pilot plant and minimize unnecessary expenditures during the pilot stags it is reconffiended that semi-continuous coordinated bench scale tests be carried out. These should include the following process segments: 1. Hydrochloric acid leaching of pyrite flotation tailings and roaster residue. 2. Solvent extraction of uranium; precipitation, dewatering and drying of yellowcake. 3. Solvent extraction of thorium" from uranium raffinate; precipitation, dewatering and drying of thorium oxalate. 4. Extraction of radium by two-stage 1on exchange. 5. Regeneration of hydrochloric add with sulphuric acid. Grinding, pyrite flotation and roasting can be carried out separately to provide feed for the leaching circuit. 4.2 High Grade Ore The chlorination process has the potential to substantially decrease radium levels in tailings wastes. 4.0 CONCLUSIONS ASP RECOMMENDATIONS 4.2 High Grade Ore - Continued However, at the time this study was initiated, it had not been demonstrated 1n the laboratory that radium levels in the tailings waste could be reduced to a level approaching the desired standard of 15 picocuries per gram. Uranium extraction 1s quite high and In the order of 98%. Capital and operating costs for the process, based on costs per ton of ore, are quite high. Costs might be reduced substantially by preconcentratton, for example, by radioactive sorting, screening, flotation, gravity concentration or a combination of these. Ths chlori nation process has not been completely tested in the laboratory. It is rsccssnended that bench scale test work be continued. Tha crimary objective o? continuous usavk should ht. to increase radiua extraction. This objective might be achieved by: 1. Adjusting chlorination conditions, preferably in a fluid bed, rather than static reactor. 2. Grinding the calcine product prior to leaching to overcome possible.sintering effects. 3. Higher concentration of hydrochloric acioi in leaching and/or pressure leaching at higher temperatures. The process could be simplified 1f all the uranium were recovered In the chiorination gas product. This would eliminate the uranium recovery section in the chlorination residue leaching circuit. If satisfactory radium extraction is achieved, test work should also be carried out in other areas which have not been adequately investigated, including the following: 1. Chlorfne regeneration and recovery 2. Arsenic separation 3. Caustic leaching of oxide residues. Evaluation of these test results would be necessary before considering a pilot plant program. LUMMUS
5.0 STUDY CRITERIA The following criteria were used as a basis for evaluation of the selected processes: 1. Radium to be extracted fn s form suitable; for long term storage. Tailings radioactivity objective: Lew grade ore: 15 picocuries par gram (pC1/g) High grade ore: as low as practically possible. 2. Thorium extraction to be as high as practically possible on ores containing thorium. 3. High uranium extraction, preferably about 98X. 4. Minimum effect on the environment from toxic and undesirable elements 1n the ore, or Introduced in the process, e.g. sulphuric acid, nitrate, chloride and arsenic. 5. Safe working environment achievable.in the plant. 6. Proven unit processes to b-a used as far as possible. 10 7. Optimum energy utilization. ft. Minimum capital and operating costs within the restraints of other criteria. For study purposes, the following ore analyses were assumed: Analysis, % Elejnent Low Grade High Grade
U308 0.1 2.5 Th 0.44 0.01 Ra 350 pC1/g 6,000 pCI/g Fe 3.5 3.6 Si 39 27 S 3.0 1.2 As 4.0 The low grade analysis is typical of Elliot Lake ores. The high grade analysis is more or less *.ypical of Saskatchewan ores; however, these show wide variations in mineral coraposition. %,fc .; • Most high grade ores 1n Saskatchewan contain Insignificant concentrations of thorium. Therefore, thorium removal has not been inciuoed in the process for high grade ore. ^
LLMMUS
6.0 PROCESS FOR LOW GRADE ORE (0.1X U3O8)
6.1 Process Description
A general process flow diagram for the low grade ore 1s shown on [Yawing No. SKD-9309-001C0-2 in the Appendix.
The hydrochloric acid leaching process for low grade uranium ores 1s a combination of the following process steps:
1. Grinding and pyrite flotation.
2. Roasting of pyrite and production of sulphuric add.
3. Hydrochloric acid leaching of flotation tailings and roaster residue.
4. Separation and precipitation of uranium as yellowcake. a 5. Separation and purification of thorium and radium. 6. Regeneration of hydrochloric acid.
7. Preparation of mine backfill.
Grinding and Pyrite Flotation
To achieve the required extraction efficiency, the ore is wet ground to 60% -200 mesh.
In order to minimize environmental problems, pyrite 1s floated with an efficiency of 90X or better, and the flotation concentrate sent to roasting. Tailings are sent directly to hydrochloric add leaching.
Roasting of Pyrite and Production of Sulphuric Add
Pyrite Is roasted 1n a fluid-bed roaster, and the sulphur dioxide gas 1s cooled in a waste heat boiler, and cleaned in electrostatic precipitators before passing to the sulphuric acid plant. Acid production amounts to 142,000 tons/year, most of which is used to regenerate hydrochloric add. It Is assumed that the remainder, amounting to 33,000 tons/year is marketed. Ho allowance has been . made for revenue from add. o;u»^: v . ,•/•.,-' •••;;; - • ..;.„• •.. ••
Calcine from the roaster, together with dust collected from the precipitators is slurried and pumped to the leaching section. I LUWMUS
6.0 PROCESS FOR LOW GRADE ORE (0.1% U30a)
6.1 Process Description Separation and Purification of Thorium and Radium - Continued been loaded with radium, the complete column, Including the resin and protective shield, 1s disconnected and transported to a permanent, safe storage facility. Transportation and storage of the radium is excluded from the scope cr this study. The barren liquor from the radium section, now depleted of radioactive elements 1s treated to recover hydrocnloric add. Regeneration of Hydrochloric Acid This step 1s required to recover chloride ions, which cannot be discharged to tailings, iirui return them to the nrncess in *•-.<» form of hydrochloric acid which is used for leaching. The process uses the principles of the vapour pressure of hydrochloric acid being l©*er than that of water, and the low solubility of gypsum. By treating the barren liquor with sulphuric acid, produced on sits, the chloride Ions are converted to hydrochloric acid and t^e sulphate in the sulphuric acid is precipitated as gypsum. Hydrochloric acid is recovered from the liquor in a conventional distillation column and an absorption tower and the gypsum is disposed of. Mine Backfill Leach residue is repulped and treated with a small amount of lime to neutralize any acid not removed by washing. The residue is classified by two-stage cycloning to produce a sand product suitable for mine backfill, and a fine product which is disposed of in a tailings pond. Utilities Utility requirements are listad on Drawing No. SKD-9309- 00170-0 in the Appendix. Two high pressure boilers produce steam. The high pressure stean 1s used to generate part of the power used in the process. Low pressure steam from the turbines 1s used primarily for heating leach slurry and distilling hydrochloric acid. Additional steam is produced in an waste heat boiler on the roastsr. This steam is used to generate power and operate the blower in the acid plant...... -,:. -—A
6.0 PROCESS FOR LOW GRADE ORE (0.1X U308) 6.1 Process Description - Continued Hydrochloric Acid Leaching Pyrite flotation tailings, together with roaster calcine, is leached in two stages, using hydrochloric acid. This dissolves the uranium, thorium and radium. The leach slurry is filtered and washed to recover the radioactive minerals. About 2/3 of the leach liquor is recycled to the head of the leaching circuit to minimize the quantity of liquor in subsequent treatment stages. The remaining 1/3 advances to the uranium recovery circuit. Separation and Precipitation of Uranium as Yellowcake The pregnant liquor is clarified and treated in a solvent extraction circsit. L'r;r:vjr: i; :»tree ted Irs 6.. ur^auii. phase i,unla"miny tri-butyl phosphate (fBP) and kerosene. Uranium is stripped from y the organic phase with water and is precipitated with a slurry of magnesia (MgO) in water. The slurry is filtered, washed and dried Ft to meet yellowcake product specifications. Barren uranium solution (raffinate) from solvent extraction is pumpsd to the thorium circuit. Separation and Purification of Thorium and Radium Separation of thorium from the uranium barren solution is achieved by solvent extraction using kerosene, alcohol, and an amine. Thorium is stripped with hydrochloric acid solution. After stripping, the strip solution is evaporated in a single effect evaporator to . remove excess hydrochloric acid and to concentrate thorium in solution. Thorium is precipitated as thorium oxalate by addition of oxalic acid solution. The precipitate is washed and filtered on a horizontal belt vacuum filter, and the filter cake dried in a turbo-tray dryer. The dry product fs packed in suitable containers for storage for possible future marketing. After extracting the thorium, the aqueous raffinate solution is passed through a continuous ion exchange column to remove r'.dium. At suitable intervals the radium is extracted (eluted) frun the resin in dilute concentration and is further concentrated in fixed bed ion exchange columns. These co'uranS' are disposable and are shielded to protect personnel from radiation. When a column has 6.0 PROCESS FOR LOW GRADE ORE (O.Ig U3O3)
6.2 Basis for Capital Cost Estimate
The plant is designed on the following basis:
Plant Feer : 5,200 tons/day at 2.0 1b. l^Gg/ton
Uranium Recovery: 98*
Yellowcake Production: 10,000 Ib/day as U3O3
Capital costs are for the battery limit plant, from receipt of ore front the nine to storage of products. Tailings pumps are included, but no allowance made for tailings lines or disposal area.
The following costs are excluded:
- Process development - LdiiU COSCS - Costs associated with environmental hearings, permits, etc. - Owner's costs daring design and construction All costs shown in the estimate are in Canadian dollars, and reflect current prices and costs associated with the installation of the plant in Central Canada. Ho allowance has been made for escalation. The estimates are based on very preliminary designs, and are considered to have an accuracy of £ 30%. Equipment costs were estimated from vendor quotations or in-house data. Building costs were estimated on a square foot basis. Estimated building sizes are shown on li
6.0 PROCESS FOR LOW GRADE ORE (0.1X U308)
6.3 Capital Cost Estimate Capital costs are estimated to be as follows: Installed cost of equipment: Grinding and flotation of -ite 15,900,000 Roasting of pyrite and sulphuric acid plant 20,100,000 Leaching with hydrochloric acid 39,700,000 Separation and precipitation of uranium as yeliowcake . 6,700,000 Separation and purification of thorium and radium 9,400,000 Regeneration of hydrochloric acid 12,700,000 Mina backfill 2.900,GOO
Cost of buildings: 21,700,000 Cost of utilities: 9,700,000 TOTAL DIRECT PLANT COST 138,800,000 •xsarsacsssafcx 6.4 Basis for Operating Cost Estimate The estimates provided in this section do not include taxes, interest payments, depreciation or head office and marketing costs. Assumptions Plant availability 90% or 330 days/year Cost of electric power 2.67 {/kUh Fringe benefits on wag»s and salaries 30X Electric power factor 90% Mo. of employees 310 Lime $40 per ton -•freestone $15 per ton Hydrochloric acid (32*) $80 per ton Sodium tydroxide (76S) $200 per ton Maintenance materials and 55. of process equipment cost supplies It of utilities equipment cost Stean pressure 600 to 100 lbs/in2 LUMMUS
6.0 PROCESS FOR LOW GRADE ORE (O.IX U308) - Continued
6.5 Sumnary of Operating Cost Estimate Annual
Item Units Consumption S $/1b U308
Wages and Salaries No (310) 7,300,000 2.212 Maintenance 5,470,000 1.658 Materials Electrical Energy kwh 34.14 x 106 900,000 0.276 (net) Steam BTU 16.18 x 1011 4,900,000 1.485 Water gal 2.4 x 108 240,003 0.073 Major Chemicals 2,490,000 0.755 Operating Reagents 1,240.000 0.371
TOTAL DIRECT OI'E^ATIKG COSTS 22.540,000 6.830 Cost per ton of ore $13.13 LUMMUS
6.0 PROCESS FOR LOW GRADE ORE (O.IX U3O3) - Continued
6.6 Detailed Operating Cost Estimate
Annual Item Units Consumption S 000's $ OOO's Wages and Salaries Salaries (incl. No. (31) 900 1 fringe benefits) i Wages (fnci. fringe Ho. (279) 6.400 benefits) Total Wages and Salaries (310) 7,300 Electrical Energy
6 Total Electrical Energy kwh X 10 66.22 1,740 Credit for Co-generation 32.03 840 Net Electrical Energy Used 34. ill 90G Steam BTU x 1011 Hydrochloric acid leaching 5. .78 Hydrochloric acid regeneration 8..95 Overall plant heating (5OX of 1. .45 tine) Total steam 16. ,18 4,900 4,900 Process Water: gals x 10^ 2. 4 240 240 Maintenance Materials: 5,470 5,470 Major Chemicals Lime tons 14,000 560 Limestone tons 99,700 1,500 Hydrochloric add (32%) tons 2,270 130 Sodium hydroxide (76X) tons 1,250 250 Total chemicals 2,490 WS LUMMUS
6.0 PROCESS FOR LOW GRADE ORE (0.1X U3O3)
6.6 Detailed Operating Cost Estimate - Continued
Annual Item Units Consumption $ 000's $ OOO'S Operating Reagents and Supplies
Solvent loss 300 Stripping agents 36 900 Mill liners, balls, xanthate & frother 1,236 Total Oper. Reagents & Supplies 22,536 TOTAL DIRECT OPERATING COST sn LIMMUS
6.0 PROCESS FOR LOW GRADE ORE (0.1* U308) - Continued I 6.7 Discussion According to experimental data from the Department of Energy, Mines and Resources, hydrochloric acid leaching of low grade ore will extract thorium and radium to the extent that the residual radiation level in the tailings will be much lower than 1n existing milling operations and can meet the environmental criteria of IS picocuries per gram. By recovering about 90* of the pyrite in the ore by flotation and roasting it to produce sulphuric acid, the sulphur content of the tailings can be reduced to the point where sulphuric acid generation in the tailings will be very limited and long term neutralization of tailings run-off water will not be necessary. By regenerating hydrochloric acid from spent leach liquor, chloride •Una die rev.jrC.icu Lw Lite leaciiiiig circuit aitu are prevented frun discharging to the environment. Nitric acid and ammonia are not used in the process and therefore nitrogen compounds will not appear In tailings effluent to contaminate waterways. Due to the low radioactivity of waste residues, the coarser fractions of these could be utilized for mine backfill and construction of tailings embankments. Approximately two-thirds of the waste residues would be suitable for these purposes. The amount that could be used in the mine depends on the nature of the ore body and on mining methods used. Nevertheless, a substantial reduction in the quantity of tailings requiring surface disposal 1s possible. Considering the plant environment, hydrochloric acid Is corrosive and irritates the skin and lungs. However in most of the circuit the acid concentration 1s not high. In areas of high concentration the plant can be designed to be operated quite safely. Handling and transportation of concentrated radium concentrate could be hazardous but technology is available to design a safe system. The system should be no more hazardous than one for handling radium produced by chemical precipitation, which is another alternative being considered by environmental authorities. Comparing the economics of the hydrochloric acid leaching process with conventional sulphuric acid leaching is beyond the scope of this study, however a rough comparison has been attempted for what it is worth. , LUtfMUS
6.0 PROCESS FOR LOW GRAPE ORE (0.1S l'3O8)
6.7 Discussion - Continued
There Is a paucity of public Information on capital and operating costs for Canadian uranium mills. Moreover, Increased production capacity 1n recent years 1n low grade areas has come almost entirely from plant expansions or rehabilitations rather than greenfield- 1 plants. Light and Coleman {"Today's Uranium Hilling Costs", ASKE Preprint No. 77-K-359) estimated the capital cost for a sulphuric acid leaching plant of 3000 tons/day to be $ US 11,000 per dally ton of capacity 1n 1977. Factoring these figures for higher tonnage, escalation and exchange rates, the cost for a 5200 ton/day plant in 1S30 1s calculated to be about $72 million. This compares with a capital cost of $139 million for the hydrochloric acid leach plant. However, the latter plant includes facilities for pyrite roasting anJ uCiJ ^iisi alioft KJiii.ii yrovities sne leacnant Tor uranium i extraction. Light and Coieman, in the same article, indicate a direct operating cost of $7.20 per ton for a sulphuric acid mill, equivalent to approximately $12.00 per ton in Canada in 1980. This compares with $13.13 per ton for the hydrochloric acid leaching plant.
Based on the above figures, the hydrochloric add leach process compares unfavorably with sulphuric add leaching due to the high capital cost of the plant facilities. To make a more meaningful comparison, an evaluation of the following factors, which favor the hydrochloric add route, would be required: - The reduced cost of tailings ponds due to reduced tonnage of tailings. - Radium chloride treatment, Including expensive settling ponds, is unnecessary. - Long term neutralization of add effluent from tailings is not required.
-••i
a LUMMUS
7.0 PROCESS FOR HIGH GRADE ORE (2.5X
7.1. Description
A general process flow diagram for the high grade ore is shown on Brewing No. SK0-9309-0OZ00-2 in the Appendix. The chiorination/hydrochloric acid leaching process for high grade uranium ore consists of the following process steps: 1. Grinding 2. Drying 3. Chlorination and chlorine regeneration 4. Hydrochloric acid leaching and alkaline leaching 5. Uranium extraction and precipitation as yellowcake 6. Extraction and separation of radium 7. Regeneration of hydrochloric acid and neutralisation of sulphuric acid Tili f*? "y!rn i Mine backfill is not produced because high grade Saskatchewan mines are open pit operations which do not require backfill. Grinding To achieve satisfactory extraction of uranium, the ore Is wet ground to 60S minus 200 mesh. Wet grinding 1s employed to minimize emissions of radioactive dust and radon gas. Ground slurry 1s thickened and filtered and the filter cake conveyed to. a fluid bed dryer. Drying In order to obtain high chlorination efficiency the ore has to be bone dry. The dryer bed product is conveyed to the chlorination section. Oust carried over from the dryer in exit gases is. collected by cyclones and a bag filter, and joins the bed overflow materi al. Chlorination and Chlorine Regeneration Chlorination of the total ore 1s carried out in a series of two fluid bed reactors and a fluid bed cooler. Tests have shown that two stage chlorination is necessary to maximize overall recovery of uranium, radium and arsenic by chlorination and subsequent operations. The first reactor operates at 250°C, the second at 900°C and the cooler at 100°C. ff Fluidisation in the first two chlorination reactors Is achieved with LUMMUS
7.0 PROCESS FOR HIGH GRADE ORE (2.5X U303)
7.1 Description - Continued Exit gases from both chlorination reactors contain chlorides of uranium, Iron, nickel and arsenic but no radium. These gases are passed to a chlorine regenerating reactor, in which oxygen reacts with the volatile metal chlorides and releases chlorine gas. All the metals are convertec to oxides, which, with the exception of arsenic oxide, are solids at the high temperatures employed in the reactors. The off-gases from the regenerator are passed through hot cyclones and filters to remove the solid oxides. These oxides, combined with the regenerator underflow product are conveyed to an alkaline leaching circuit to recover uranium. Arsenic oxide, which is still In the gaseous form, passes through the dust collectors. Subsequently, V: is condensed by cooling and 1s collected in a cold bao fi1*0""- Vr>a »«"=eB1c c.rids predict It p*c!::gcd fcr sale. The cleaned off gas from the regenerator is treated to recover chlorine. It is separated from the other gases by scrubbing in cold water. Traces of chlorine remaining in the other gases are removed by caustic scrubbing. The chlorine scrubber water is heated to distill the chlorine, which Is dried and liquified by compression and refrigeration. Liquid chlorine is recycled to the chlori nation circuit. Alkaline leaching Most of the uranium in the ore 1s volatilized by chlorine. It 1s extracted from the regeneration reactor solids by a conventional carbonate-sodium bicarbonate leaching process. The uranium is precipitated from the leach liquor with caustic soda and 1s recovered as yeiiowcake. Hydrochloric Acid Leaching Calcine product from the chlorination reactors is leached with hydrochloric add to extract uranium and radium. This leaching circuit flowsheet Is similar to that used for low grade ore but the tonnage treated 1s much smaller. Uranium is extracted from the hydrochloric acid leach solution by solvent, extraction. Uranium Is stripped from the solvent and precipitated with magnesia. The slurry 1s filtered and the filter cake combined with the caustic leach uranium product prior to drying. LUMMUS
7.0 PROCESS FOR HIGH GRAPE ORE (2.5X U3Og) 7.1 Description - Continued Extraction and Separation of Radium Radium 1s extracted frun the solvent extraction raffinate by two stages of ion exchange. The circuit 1s similar to that described earlier for low grade ore. i Hydrochloric Add Recovery The system used fcr recovery of hydrochloric acid is similar to that 1 used in the low grade plant, but 1s much smaller because of the reduced flow rates Involved. § Tailings Disposal Residues from both leaching circuits are slurried with water and 15 pumped to a tailings pona. Utilities Utility requirements are outlined on Drawing No. SKD-9309-00270-0 in the Appendix.
7.2 Basis for Capital Cost Estimate
The plant is designed on the following basis:
Plant Feed: 200 tons/day at 50 lbs O^Os/ton Uranium Recovery: 98% as U3O3 Yellowcake Production: 10,000 lb/day Battery Limits: all plant, buildings, and fixed equipment from receipt of ore from the mine at the coarse ore bin to storage of all products. Tailings pumps are Included, but not the tailings line or disposal area.
The following costs ere excluded: - Process development - Land costs - Costs associated with environmental hearings, permits, etc. - Owner's costs during design and construction - Stockpiles or blending facilities to provide consistent mill feed. I LUMMUS
7.0 PROCESS FOR HIGH GRADE ORE (2.5* U308) - Continued
7.2 Basis for Capital Cost Estimate - Continued
All costs shown in the estimate are 1n Canadian dollars and reflect current prices and costs In northern Saskatchewan. No allowance for escalation has been made. The estimates are based on very preliminary designs and are considered to have an accuracy of + 30%.
Equipment costs were estimated from vendor quotations or in-house B data. Installed costs were factored from equipment costs, and building costs were estimated on a square foot basis. Estimated building sizes are shown in the Plot Plan (SKD-9309-0021-1) in the Appendix. Utilities were estimated from vendor quotations and from capacity correlations.
7.3 Capital Cost Estimate
Capital costs are estimated to ba as follows: a I Installed cost of equiment:
Grinding 3,600,000 Drying 1,000,000 Chlorination and chlorine 12,600,000 regeneration Hydrochloric acid and alkaline 12,000,000 leaching Uranium extraction as yellowcake 6,700,000 Extraction and separation of radium 2,700,000 Tailings disposal 100,000 Regeneration of hydrochloric acid 8,900,000
Sub-Total - Installed Equipment 47,600,000
Buildings: 17,200,000
Utilities: 2,200,000 TOTAL DIRECT CAPITAL COST 67,000,000 I LUMMUS
I 7.0 PROCESS FOR HIGH GRADE ORE (2.5X U3Q3) 7.4 Basis for Operating Cost Estimate The estimates provided in this section do not include indirect costs such as taxes, interest payments, depreciation, or head office expenses. No specific site has been selected, and no allowance has been made for costs incurred due to remote location such as housing, transport of employees from settled communities, and extra cost of transportation of supplies. . Since the process used for high grade is a conceptual one which has not been fully tested in the laboratory, estimates of operating and maintenance labour complements are preliminary. The personnel requirements do not reflect tonnage throughput, but rather the sophisticated nature of the process. 1 Assumptions Plant availability 90S or 330 days/year Cost of electric power 2.67 $/kWh Fringe benefits on wages and salaries 30X Electric power factor Not applicable (from grid) Plant employees 297 Lime $40 per ton Limestone $15 per ton Sulphuric acid (96%) $40 per ton Hydrochloric acid (32X) $80 per ton Chlorine (liquid) $180 per ton Sodium hydroxide (76«) $200 per ton Maintenance Material Costs 5X cf process equipment cost 1% of utilities equipment cost Steam pressure 600 to 100 lbs/in2
I LUMMUS
7.0 PROCESS FOR HIGH GRADE GRE (2.5X U3O8)
7.5 Summary of Operating Cost Estimate ;. '-% Annual Item Units Consumption $ $/lb U3O3
Wages and Salaries No. (297) 7,100,000 2.152 Maintenance 2,400,000 0.727 Materials Electrical Energy kwh x 10", 23.7 630,000 0.191 I Steam BTU x lOj1 5.81 1,750,000 0.530 Water gal x 106 95 100,000 0.030 Chemicals 1,910,000 0.579 Solvent Loss 100,000 0.030 Reagents and 60,000 0.019 Supplies TOTAL DIRECT OPERATING COSTS 14.050,000' 4.258 Cost per ton of ore $213.00 7.0 PROCESS FOR HIGH GRADE ORE (2.5X U308) - Continued 7.6 Detailed Operating Cost Estimate Annual Item Units Consumption $ OOP's $ 000's
Wages and Salaries Salaries (incl. No. 900 fringe benefits) Wages (incl. fringe benefits) No. 6,200 Total Wages and Salaries No. 7,100 Electrical Energy kuh X 106 620 620 Steam BTU X 1011 Hydrochloric acid leaching 0.83 Hydrochloric acid regeneration 1.66 Chi orination and chlorine re- generation 1.66 Plant heating (50X of time) 1.66 Total steam 5.81 1,750 1,750 Process Water: gals x 1O6 95 100 100 Maintenance Materials: Process plants 2,380 Utilities 20 Total Maintenance Materials
i 7.0 PROCESS FOR HIGH GRADE ORE (2.5* U3O8) 7.6 Detailed Operating Cost Estimate - Continued
Annual Item Units Consumption $ 000
Major Chemicals Lime tons 3,000 120 Limestone tons 24,000 360 Sulphuric acid (96%) tons 29,000 1,160 Chlorine (liquid) tons 1,270 230 Sodium hydroxide (70*) tons 200 40 Total chemicals 1,910 Operating Raagents and Supplies Solvent loss 100 16 Stripping agents 10 Kill liners, balls flocculant : 120 Total Oper. Reagents & Supplies 14,000 TOTAL DIRECT OPERATING COST
.'..«'S::.'.'.VS:j'J-.i;>.-1.j,;ij^i s &K>V« wV?;;.s.ftiji!piT1s:V „
fcs^^ 7.0 PROCESS FOR HIGH GRADE ORE (2.5X U308) 7.7 Discussion Saskatchewan ores testea at CANMET contained radium 226 emitting radiation in the order of 5500 picocuries per gram. Laboratory results reviewed by Lumnus indicated that the objective of IS pCi/g in the tailings was not achieved by chicrination and leaching techniques. In fact, lowest radium levels in chlorination residues 1^"** J were in the order of 2000 pCi/g. If the experimental program is continued the first objective should be to increase the radium extraction, and if possible, approach the radioactive criteria. It is recognized that it may not be practical to attain the desirable levels. Uranium extraction by chlorination and residue leaching is quite high, in the order of 98%. A major advantage of chlorination i. *:at almost complete removal of arsenic is feasible. Arsenic trioxide probably could be recovered as a marketable product. ..•*. Nitric acid and amnonia are not used in the process and therefore nitrogen compounds will not be present in the plant effluents. By regenerating hydrochloric acid from spent leach liquor, chloride ions are recycled to the leaching circuit and are prevented from discharging to the environment. Although processes employing hydrochloric acid and chlorine are potentially hazardous, safe operation can be attained by proper Dlant rlptinn ?n !%;vfe#;-^-<'|:Vf^ ; LUMMUS APPENDIX LIST OF DRAWINGS LOU GRADE ORE: 1 SXD-9309-00100-2 General Process Flow Diagram: HC1 Leaching Process SKD-9309-00170-0 General Process Flow Diagram: Utility Distribution SKD-9309-00011-1 Plot Plan: HC1 Leaching Process i HIGH GRADE ORE: SKD-9309-00200-2 General Process Flow Diagram: Chlorination/HCl Leaching Process SKD-93O9-OO270-0 General Process Flow Diagram: Utility Distribution SKD-9309-00021-1 Plot Plan: Chiorination/HCL Leaching Process I .^-^«2;i.i^ \STREAM UNIT FLOTATION PYRITE [SULPHURIC SULPHUNK YELLOW ROASTER : LEACH URANIUM SPENT COMPONENT, TAILINGS CONC. ACID ACID CAKE CALCINE SOLUTION RAFFINATE SOLUTION SOLIDS 202 — O.J08 IZ.35 T" — LIOUID TPH 26 24 5.0 i3.ec — — 90 90 90 PULP TPH 226 18.0 • — SOLIDS 80 0.0 — 100 0.0 REMARKS GRINDING AND FLOTATION Of PYR1TECF" S*> LEACHING SEPARATION WITH AND HYCfttXMOBIC ACID HKC)HTATIOIi OF UMNIUM (»CL) AS YELLOW CARE -140 -BO ^——^LIMESTONE ^ TAILINGS DISPOSAL UTILITIES AND SCKVICC» MINE SACK FILL : -180 o o o RX o SPENT H»DBO- LIMESTONE LEACH THORIUM CHLORIC GYPSUM OUITIOH ACID (C» COj) RESIDUE PRODUCT 14.14 216 24.32 1.9 TPD IS 90 JI.J 0.25 6.08 G8AMS/DAr 14.39 30.40 0.0 SO 2-3 0%HCL tSTHCWIU^ASRAWUM ROASTING OF PYRITE AND SULPHURIC ACID VELLOW CAKE TO MARKET ' SEPARATION AND PURIFICATION 1HMUUM * MtMM ISSUED FOR REPORT L TO Th STORAGE CLIENTS COMMENTS INCORB ' FOR THE FUTURE MARKET ISSUED FOK INFORMATION TO Rg tONC PtRWO »TORACE REGENERATION or M ci ACit ANO NEUTRALIZATION -LOW GRADE - OF WLPHURK ACN> .****«* -HO GENERAL PROCESS FLOW DIAGRAM H CL LEACHING PROCESS FOR URANIUM \_^ ^l^^d^:^ LOW PRESSURE STEAM U/H PROCESS WATER ELECTRIC POWER (KW ) BOILER MAKE UP WATER 100 M ao so 7» ao so so 410 CNEIMU.FtAMT HMDH6 MO UCHTMB MMHTEHMKE «HOf M» RAM SMMTIOM H*t WHMC i PflfCinUTW M OF UMNWM ASYCUAW CMC ton mront -LOW 6RA0E- 6ENE9AL PROCESS FLOW OtAGAAM HCLLEACWNG PROCESS FORURANUMORE " UTIUTY DISTRIBUTION faikj^i^JiJ^^ 225-0* 200-0* 60-0' I TRIPPER COW. I FROM MINE ROASTER , BUILDING GRINDING AND -OOI30 , FLOTATION OF M'-JtZM'- PTRITE BUILONS / I ( -oouo I i i i i i i i i i i i / / / URANIUM / UACHiNG /'SEP*>*T!OH : H / 8UILDIK6 / ^PRECIPITATION A , BUILDING -00150 / / J 'til SAND • STORACE TANKS AND MME 0ACKF1U •£B»-CEMENT SILO "1 ••-..•3 9O'-O* HACK I I I I PIPERACKI I I a SUCK istutD ton atrcm SSUepPOO MfOHMATIOM •sa \ COOLING TOWR -LOW GRADE- -FEMCC UNC PLOT PLAN H CL-LEACHING PROCESS FOR URANIUM ORES (O.I %U,O,J • f.4o'-o' I owo. woSKD 9300-0001 -1 1 T ' . 1 ! 1 1 <3> I HYOROCHLORIC U- EXTRACTION ACID AND I LEACHING PRECIPITATION AND ALKALINE AS YELLOW CAKE LEACHING -240 i •:-'••.'•' • 1 <'> <£> <3> <$> REMARKS AS US0S C3- -220 HYDROCHLORIC U-EX TRACTION ACID AND LEACHING PIKCIPITATION AM) ALKALINE AS YELLOW CAKE LEACHING -240 -2M UTILITIES TAIL IN tS DISPOSAL AMD SERVICES HYDRO- CHUM CHLORIC SULPHUR* QUICK LIME ACID ACID nue STONE 10 1.0 W5/DIW 2.6 1.07 100 98 %> CW.ORINATI0N AND CHLORINE REGENERATION -ao TtLLOW CAKE TO MARKET EXTRACTION ANO SEPARATION OF RADIUU -260 ISSUED FOft REPORT GS CLIENTS CCMUCNTS IHCORft fefr* ISSUEDFOR INFORMATION REGENERATION OF HYDROCHLORIC ACID ANO NEUTRALIZATION Of SULPHURIC ACID — HIGH GRADE - -iSO GENERAL PROCESS FLOW DIAGRAM CHLORINATION/H CL LEACHING PROCESS FOR URANIUM ORES (3.5 HIGH PRESSURE STEAM LB/H LOW PRESSURE STEAM LB/H COOLING WATER (USCPM; 5 000 55000 (7) 2000 (?) 100 2000 (T) 1200 (e) 6oo 7000 (^ 100 ^) — 5000 1000 (7) 600 (jo) 100 2 000 (£_) 300 8 000 soo 20 000 (7) 100 STEAM •CUE* Nil TO OOO Lfl/H CAPACITY r oooCOOLWC 10WE* o I (USGPM) PROCESS WATER (uSGPu) ELECTRIC POWER IKW) BOILER MAKE UP WATER (usom) 3250 100 200 o 100 6O0 30 30 60 100 © 30 © 600 30 IS ADMINISTRATION OVERALL BUILOING PLANT HEATING AND LIGHTING SEPARATION AND PRECIPITATION OF URANIUM AS YELLOW CAKE A ISSUED FOR REPORT OS W ssr -HIGH GRADE- iLUMMUS GENERAL PROCESS FLOW DIAGRAM CHLORINATION/H CL LEACHING PROCESS UTILITY DISTRIBUTION IDWG. NO.SKD9309-00270-0 • . I ... ..' . LUMMUS 7.0 PROCESS FOR HIGH GRADE ORE (2.5X U308) - Continued 7.6 Detailed Operating Cost Estimate Annual Item Units Consumption $ 000's $ OOO's Wages and Salaries Salaries (incl. No. (30) 900 fringe benefits) Wages (incl. fringe benefits) No. (267) 6,200 Total Wages and Salaries No. (297) 7,100 Electrical Energy Icwh X 106 23.0 620 620 Steam BTU X 1011 Hydrochloric acid leaching 0.83 Hydrochloric acid regeneration 1.66 Cnlorinaticn and chlorine re- generation 1.66 Plant heating (50% of time) 1.66 Tztzi ctcc~ I/.Gi 1,73C. iT75G Process Water; gals x 106 95 100 100 Maintenance Materials: Process plants 2,380 Utilities 20 Total Maintenance Materials 2,400 | . • ^^<^^^-^-'W:: ^ I LUMMUS 7.0 PROCESS FOR HIGH GRADE ORE (2.5X U308) 7.6 Detailed Operatinq Cost Estimate - Continued Annual Item Units Consumption $ 00OOO'0 s % OOO's 1 Major Chemica7s Lime tons 3,000 120 Limestone tons 24,000 360 Sulphuric acid (96*) tons 29,000 1, 160 Chlorine (liquid) tons 1,270 230 Sodium hydroxide (7O!6) tons 200 40 Total chemicals - - 1,910 1 Operating Reagents and Supplies ' Solvent loss 100 Stripping agents 16 Mill liners, balls flocculant _10 Total Oper. Reagents & Supplies 120 TOTAL DIRECT OPERATIKG COST unm 83IS£= I 1 I LUMMUS 7.0 PROCESS FOR HIGH GRADE ORE (2.5% U308) mi 7.7 Discussion tzvz Saskatchewan ores tested at CANMET contained radium 226 emitting radiation in the order of 5500 picocuries per gram. Laboratory results reviewed by Lumnus indicated that the objective of 15 pCi/g Wi in the tailings was not achieved by chlorination and leaching \ techniques. In fact, lowest radium levels in chlorination residues were in the order of 2000 pCi/g. If the experimental program is continued the first objective should be to increase the radium extraction, and if possible, approach the radioactive criteria. It is recognized that it may not be practical to attain the desirable levels. H'SS Uranium extraction by chlorination and residue leaching is quite high, in the order of 9BX. A major advantage of chlorination •. "*at almost complete removal of arsenic is feasible. Arsenic trioxide probably could be recovered as a marketable product. Nitric acid and ammonia are not used in the process and therefore it pcundds wii" nut be present in tne plant ettiuents. By regenerating hydrochloric acid from spent leach liquor, chloride ions are recycled to the leaching circuit and are prevented from I '•'-••'.X discharging to the environment. Although processes employing hydrochloric acid and chlorine are potentially hazardous, safe operation can be attained by proper plant design and by employing well trained operators. Fluid bed chlorination is well proven in other metallurgical operations, for example, titanium. Capital and operating cost data for high grade uranium mills have not, to our knowledge, been published. UNIT ORE FILTER our CHLORINE LEACH LEACH »£LLOW BARREN FROM CAKE CAS RESIDUES RAFFWATC SOLUTION ft COMPONENT MINE ORE SOLUTION RESIDUE CAKE SOLIDS TPH 8.4 8.4 8.4 _ 60 — 8.0 0.208 — — LIQUID TPH 1.0 I.SO — — 8.0 2X> — KXO 10.0 PULP TPH 9.4 9.90 — — — — 10.0 — — — SOLIDS »O(WT) 89 85 100 too 80 100 _ — SOLIDS S.G. ZJ — 26 — 2£ 3JS — CLj CAS LVH 320