Recovery of Nickel and Cobalt from Low-grade Laterites.
Siemens RE; Stickney WA; Wells RR
11th Int'l Miner Proc Cong Italy 4/75 Cnte Minerario Sardo Univ Di Cagliari Pp 229-42 :229-42
A process is being developed by the Bureau of Mines to selectively recover nickel and cobalt from low-grade domestic laterites. The process involves: (1) selective reduction with carbon monoxide at 350 deg to 600 deg c with additions of pyrite to those ores containing more than 5 pct magnesia, (2) a multiple stage oxidizing leach of reduced material in an ammonia-ammonium sulfate solution, (3) selective extraction, (4) precipitation of cobalt from the raffinate with hydrogen sulfide, (5) removing any magnesium present by ion exchange or precipitation. (6) Recycling the ammonium hydroxite-ammonium sulfate solution back to the leach step, (7) stripping the nickel from the solvent with dilute sulfuric acid, and (8) electrolytic recovery of the nickel from the electrolyte. Recoveries from a laterite containing 1 pct nickel and 0.2 pct cobalt were 90 pct nickel and 83 pct cobalt. In this process the energy requirements are lower than those reported for most other processes for nickel recovery.
11th Int'l. Miner. Proc. Cong., Italy, 4/75; Cnte Minerario Sardo, Univ. Di Cagliari, Pp 229-42