Recovery of Platinum, Palladium, and Gold from Stillwater Complex Flotation Concentrate by a Roasting-leaching Procedures.
Baglin EG; Gomes JM; Carnahan TG; Snider JM
Proc of Ores Concentrates & By-prod Metall Soc AIME 1985 :13 pages
The Bureau of Mines devised a procedure for selectively extracting platinum-group metals (PGM) and gold from Stillwater Complex flotation concentrate. The concentrate was roasted at 1,050 deg. C to convert base-metal sulfides to oxides and the PGM from sulfide minerals to their elemental states. The roasted concentrate was preleached with dilute sulfuric acid to remove soluble gangue minerals. After preleaching, the concentrate was slurried with 6m hcl and leached at ambient temperature and pressure with a strong oxidizing agent, such as hydrogen peroxide, chlorine, sodium hypochlorite, nitric acid, or persulfate salts. Up to 97 pct of the pt, 92 pct of the pd, and 99 pct of the au were extracted from the roasted concentrate. The base metals were not solubilized and remained in the residue. The precious metals were recovered from the pregnant solution by sulfide precipitation, cementation with nickel, or adsorption on activated carbon.
Proc. of Ores, Concentrates & By-prod., Metall. Soc. AIME, 1985, PP. 167-179