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Cobalt Recovery from Copper Leach Solutions.
MISSING :12 pages
Significant amounts of cobalt, a strategic and critical metal, are present in readily accessible spent copper leach solutions; for example, recovery of cobalt at two major U.S. copper operations could produce about 1,300,000 lb CO annually, about 13 pct of domestic consumption. However, techniques such as solvent extraction and precipitation have not proven cost effective in separating and recovering the cobalt from these low-grade domestic sources. The Bureau of Mines has devised a procedure using a chelating ion-exchange resin to extract cobalt from a ph 3.0 Copper leach solution containing 30 mg/l carbon monoxide. Cyclic tests in 4-ft-high by 1-in-diam columns gave an average cobalt extraction of 95 pct when 65 bed volumes of solution were processed at a flow rate of 4 gpm/ft2 of resin area. After an impurity scrub, eluates contained, in grams per liter, 0.4 Co, 0.2 Ni <0.001 Cu, 1.3 Fe, 2.8 Zn, and 0.008 Al. Solvent extraction procedures to remove impurities, reject nickel, and concentrate cobalt produced a cobalt sulfate solution containing 80 g/l CO, 0.05 G/l ni, and not more than 1 mg/l cu, fe, zn, or al. Based on data from commercial electrowinning operations, this solution appears suitable for production of metallic cobalt.
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Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division