Cobalt recovery

Lateritic Ores. The process used at the Nicaro plant in Cuba requires that the dried ore be roasted in a reducing atmosphere of carbon monoxide at 760°C for 90 minutes. The reduced ore is cooled and discharged into an ammoniacal leaching solution. Nickel and cobalt are held in solution until the soflds are precipitated. The solution is then thickened, filtered, and steam heated to eliminate the ammonia. Nickel and cobalt are precipitated from solution as carbonates and sulfates. This method (8) has several disadvantages (/) a relatively high reduction temperature and a long reaction time (2) formation of nickel oxides (J) a low recovery of nickel and the contamination of nickel with cobalt and (4) low cobalt recovery. Modifications to this process have been proposed but all include the undesirable high 760°C reduction temperature (9). 

Martinez, R. V. Liranza, E. G. Barzaga, B. R. Daudinot, A. M. Cobalt recovery by solvent extraction from acid leach solutions of Caron s process mixed Ni/Co sulfide. Hydrometallurgy and Refining of Nickel and Cobalt, Annual Hydrometallurgy Meeting of CIM, 27th, Sudbury, Ont., Aug. 17-20, 1997, 293-304. 

Mihaylov, I. Krause, E. Colton, D. F. Okita, Y. Duterque, J. P. Perraud, J. L. The development of a novel hydrometallurgical process for nickel and cobalt recovery from Goro laterite ore. CIM Bull. 2000, 93, 124-130. 

Using TY3 collector improved the copper recovery by 10%, while the cobalt recovery remained unchanged. The consumption of sulphidizer in the presence of TY3 was significantly reduced. 

In the 1980s, a new collector (i.e. fatty acid-modified xanthate) was introduced into the Kolwezi concentrator with significant improvement in copper recovery. In 1995, collectors from the PM series were tested in the Nchanga concentrate improving results. The plant results obtained in the Kolwezi concentrate using xanthate and TY3 are compared in Table 19.10. Collector TY3 also had a positive effect on cobalt recovery. 

The ruthenium(111) acetylacetonate-cobalt(II) iodide couple, for example, when dispersed in tetrabutylphosphonium bromide (ex. 1) and treated with 1/1 CO/H2 at 220°C, generates a liquid product containing 76 wt % acetic acid plus 1.1 wt % propionic acid (111 mmol total acid). The liquid yield increase is 66% and the estimated carbon selectivity to acetic plus propionic acids and their esters is 84%. There is normally no metallic residue at this stage, ruthenium and cobalt recovery is essentially quantitative at the end of the run, and the product acids may be recovered in >90% purity by fractional distillation. Methane and water are the major by-products (4). 

Cobalt recovery from acidic metal ion solutions is impeded by the evolution of hydrogen. However, if the pH of the solution is gradually increased, it is found that at pH > 4 this deposition is possible. 

Fig. 13. Sherritt Gordon Mines Limited, simplified cobalt recovery flow diagram. Evans (ElO).

The content of the reduction autoclaves is dischaiged into cone-bottomed flash tanks where separation of the powder from the spent liquor takes place. The nickel metal in slurry form is washed, dried, and packaged as powder or pressed into briquettes, sintered, and packaged ready for shipment. The spent liquor containing about 1 gm/liter Co and 1 gm/liter Ni is precipitated with HjS, filtered, and sent to the mixed sulfides stage for cobalt recovery. 

Several explanations may be taken into account for only a small decrease in importance an existing high-pressure infrastructure which is also used for the hydroformylation of olefins higher than propene, where cobalt-based processes are advantageous a combined cobalt recovery and recycle system for the hydroformylation of different olefins and the use of tail gases from low-pressure hydroformylation units. 

Phenylalanine, a key intermediate in the preparation of the sweetener aspartame (the methyl ester of L-phenylalanine/T-aspartic acid dipeptide) [18, 19] may be prepared similarly according to eq. (10). Amidocarbonylation of phenylacetaldehyde, obtainable from styrene, affords A-acetyl-/9-phenylalanine in 72 mol % yield and with > 98 % cobalt recovery [20]. 

Many processes utilize electrowinning for cobalt recovery. Cobalt can be deposited as high-purity metal from sulfate or chloride solutions. The electrowinning solution must be purified from metallic impurities. The following methods have been used [5, p. 820] ... 

Jeffers, T. H. Harvey, M. R., Cobalt Recovery from Copper Leach Solutions U. S. Bureau of Mines Report of Investigations 8927, 1985. 

Blazquez, I., Vicente, F., GaUo, B., Oritz, L, and Irabien, A. 1987. Application of chitosan to cobalt recovery Evaluation by factorial design of experiments. J. Appl. Polym. Sci. 33 2107-2115. 

Higher energy efficiency and higher nickel and cobalt recoveries than the Caron Process... 

Recent research has also been focusing on electrochemical recovery of cobalt from spent Li-ion cathodes. Researchers in Italy (20) and Brazil (21) investigated the recycling of cobalt from the cathodic material of Li-ion spent batteries, where the final cobalt recovery step relied on electrochemical techniques. In one example, the cathodic material (also containing nickel) was dissolved in acid, cobalt and nickel separated by solvent extraction, and the cobalt electrowon at 250 A/M, pH 4.1 and 50°C. In the other example, cathodic LiCo02 was acid leached, and the metallic cobalt deposited directly on 430 steel. The deposit was then oxidized to C03O4 in air at 850°C. 

T.H. Jeffers, M.R. Harvey, "Cobalt Recovery from Copper Leach solutions," USBM, RI 8927, 1985. 

Chromium(VI) is quite persistent once formed and will cause contamination issues in downstream nickel and cobalt recovery. It can however be easily eliminated by the addition of a reducing agent into solution before neutralization. Suitable reagents used include sulfur dioxide, hydrogen sulfide and their alkali equivalents. 

In full-sheet cathode cobalt production, cobalt deposits become highly stressed and there is a tendency for them to peel off the blanks. Therefore, it was decided to produce round cobalt buttons in divided cells. A similar product is currently produced by Vale INCO, Canada [7]. Cobalt quality is affected by pitting of the electrodeposit. In the Vale INCO s cobalt recovery process, sodium laurel sulfate (SLS) used for foam stabilization also acts as an anti-pitting agent. [8]. In the Boleo cobalt recovery process, the anolyte is used to strip cobalt from the cobalt-loaded organic solution. Sodium laurel sulfate in the anolyte interferes with cobalt stripping and even extraction by causing problems with phase separation. Sodium laurel sulfate can therefore not be used in conjunction with a solvent extraction process. 

COBALT RECOVERY THROUGH SULPHATING ROAST OF CU/CO CONCENTRATE OF KATANGA MINING... 

After coarse particulate removal by cyclones, the off-gas scrubber uses spent electrolyte for scrubbing to maximize copper/cobalt recovery for the fines. The use of water for scrubbing of off-gas dust would dilute the concentration of copper and cobalt in the spent electrolyte and have a negative impact on the acid balance in the plant. 

Table III. Copper, nickel and cobalt recovery in the alloy obtained during smelting of sea nodules on 20 kg scale in graphite lined 50 kVA arc furnace with varying coke and holding time in presence of 4% additional quartz.

Cobalt Recovery through Sulphating Roast of Cu/Co Concentrate... 

Finally, the key consideration is whether a valuable product can be produced. Whatever the product, it must be of sufficient quality to compete with other raw materials. For pyrometallurgical processes, the product competes directly with metals from ore and is refined to equivalent purity. Products from hydrometallurgical processes can also be purified to be directly competitive with virgin materials. In both of these cases, favorable economics depend on the cobalt content of the battery current recycling processes are driven by the revenues from cobalt recovery. As cobalt use declines, other incentives will be required to make the business of recycling Li-ion batteries profitable. 

Lithium battery recycling is a relatively new but rapidly expanding process. All companies mainly focus on cobalt recovery, as it is the most expensive material, but some companies (e.g. Accurec, Toxco) recover also lithium. Specialists estimate an increase of the lithium... 

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