Abstract: A hydrometallurgical process is provided for separating heavy metal nuisance elements such as As, Sb, Bi, Sn and Pb from precious metals and/or selenium. The process can be used as a step in an overall hydrometallurgical process for treating refinery residues such as anode slimes for the separation and recovery of valuable metal values.

Abstract: This invention is concerned with a process for dissolving oxidic trivalent cobalt compounds in hydrochloric acid while avoiding the generation of chlorine. It includes the following steps (a) slurrying in water the trivalent cobalt compound to be dissolved and (b) treating the resulting slurry with a reduction agent from the group consisting of methanol, formaldehyde and formic acid and with hydrochloric acid. The contact of the hydrochloric acid with the slurry should occur in the presence of the reducing agent. The rate of acid addition should be controlled to maintain the slurry at a pH above 1.

Abstract: A hydrometallurgical process for treating copper refinery anode slimes containing selenium, lead and precious metals in which a selenium product of better than 99.7% purity can be produced and the final residue is suitable for smelting to produce anodes for silver refining.

Abstract: Ferruginous sulfide minerals containing non-ferrous metal values, such as nickel and cobalt are treated to concentrate the non-ferrous metal values in metallic iron. An intimate admixture of finely-divided non-ferrous-metal-bearing ferruginous sulfide minerals, iron oxide, and a suitable reducing agent is maintained at a temperature between about 800.degree. C. and 1000.degree. C. in an atmosphere non-oxidizing to iron to produce a metallic iron alloy containing the non-ferrous metal values from the sulfide minerals. The heated admixture is cooled and the concentrated non-ferrous metal values in the iron alloy are recovered by magnetic separation or hydrocloning.

Abstract: The presence of one or more of cobalt, iron, arsenic and lead is most substantially reduced in a nickel-containing electrolyte by an electrochemical process utilizing a high current density at the cathode in an electrolytic cell containing specific quantities of chlorides of alkali metals to form a fine nickel hydroxide precipitate. In a subsequent time dependent reaction under controlled pH conditions, nickel hydroxide reacts with the electrolyte to form insoluble precipitates of cobalt, iron, arsenic and lead which are removed from the electrolyte by filtration.