Dynatec, Ltd.

Sherritt Gordon Limited

Rein Raudsepp

Derek G Kerfoot

Roman Michael Genik-Sas-Berezowsky

Felix Petrus De Kock

An improved process for separating cobalt values from nickel values in an aqueous nickel and cobalt sulphate-containing solution in which the solution is contacted with a water-immiscible organic solution containing an organophosphorous acid in a cobalt extraction circuit. The process is particularly useful for aqueous solutions containing high total metals content and elevated cobalt concentrations, while avoiding the formation and precipitation of ammonium sulphate containing double salts during the solvent extraction of the cobalt. The improvement includes contacting a portion or all of the water-immiscible organic solution required for cobalt extraction with a nickel-containing ammoniacal solution to produce a nickel-loaded organic phase and a partially nickel-depleted raffinate. The nickel-loaded organic phase is then passed to the cobalt extraction circuit for selective cobalt extraction in which nickel is displaced from the organic phase by cobalt, to produce a cobalt-depleted, nickel-enriched, raffinate and a cobalt-loaded organic phase. Advantageously, the nickel-containing ammoniacal solution is generated by adjustment of the nickel-containing raffinate from the cobalt extraction circuit, by additions of ammonia, preferably as ammonium hydroxide, and ammonium sulphate.

Solvent extraction process for the separation of cobalt from nickel in aqueous sulphate-containing solutions

A process is disclosed for separating and recovering nickel and copper values from a nickel-copper matte which may contain iron and arsenic. Finely divided nickel-copper matte is leached in aqueous sulphuric acid solution under oxidizing conditions at atmospheric pressure and at a minimum temperature of about 80.degree. C. to selectively leach nickel from the matte to produce a nickel sulphate solution having a final pH in the range of about 4.0 to 6.5, preferably about 6.5, and to produce a copper-rich sulphide residue. The copper-rich sulphide residue is separated from the nickel sulphate solution and leached in a closed reaction vessel at a minimum temperature of about 120.degree. C. under a non-oxidizing atmosphere in a sulphuric acid solution containing an effective amount of copper and sulphuric acid to provide a terminal concentration of at least about 2 g/L Cu.sup.2+ and at least about 20 g/L sulphuric acid to produce a nickel sulphate solution containing any iron and arsenic and to produce a low nickel copper sulphide product essentially free of iron and arsenic.

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St. Albert, Canada

Rein Raudsepp