Sherritt International Corporation

Jan Smit

Michael J Collins

Preston Carl Holloway

Nigel Edwin Tuffrey

Alain Tshilombo

A process to recover nickel, cobalt and copper by co-processing copper-containing sulphide concentrate feed containing one or more of arsenic, antimony, and bismuth, and laterite ore feed containing nickel and cobalt by pressure oxidative leaching. The sulphide concentrate and oxygen are controlled to produce sulphuric acid to leach nickel, cobalt, copper and acid soluble impurities into a liquid phase of an acidic leach slurry, to precipitate iron compounds and a majority of the arsenic, antimony and bismuth as solids, and to produce heat to heat the incoming feeds to a temperature above 230° C. Reacted slurry is withdrawn, solids are separated, and the PLS solution contains the nickel, cobalt, copper and acid soluble impurities. A first solution purification stage on the PLS neutralizes free acid, precipitates one or more of iron, aluminum, chromium and silicon, and, separates as solids, the precipitated impurities and other solids from a first purified solution. Copper is separated from the first purified solution with a solvent extraction step to produce a raffinate solution reduced in copper and a copper loaded organic phase. The organic phase is stripped and copper is recovered with electrowinning. A second solution purification stage is conducted on the raffinate by one or both of neutralizing free acid and precipitating one or more of iron, aluminum, chromium and silicon, followed by separating as solids, the precipitated impurities and other solids from a second purified solution. Nickel and cobalt are recovered as mixed hydroxides or mixed sulphides from the second purified solution.

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St Albert, Canada

Jan Smit