Co-processing of copper sulphide concentrate with nickel laterite ore

A hydrometallurgical process for the recovery of nickel, cobalt and copper, comprising:

• a) co-processing in a pressure vessel, a feed of a copper-containing sulphide concentrate having a sulphide sulphur concentration of at least 15 wt % and containing one or more of arsenic, antimony, and bismuth, and a feed of a laterite ore containing nickel and cobalt in a pressure oxidative leaching step under conditions including mechanical mixing, introducing oxygen, and controlling the feed of the copper-containing sulphide concentrate, the feed of the laterite ore and the introduced oxygen 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 one or more of arsenic, antimony and bismuth, if present, as solids, and to produce heat to heat the incoming feeds to a temperature in the pressure vessel above 230° C., and wherein controlling the incoming feeds and the introduced oxygen is conducted so that the sulphur content of the copper-containing sulphide feed produces sufficient sulphuric acid in the pressure vessel to leach the nickel, cobalt, copper and the acid soluble impurities into the liquid phase of the acidic leach slurry;
• b) withdrawing from the pressure vessel, a reacted slurry comprising the liquid phase and the solids;
• c) separating the solids from the liquid phase to produce a pregnant leach solution (PLS) containing the nickel, cobalt, copper and the acid soluble impurities;
• d) conducting a first solution purification stage on the PLS to neutralize at least a portion of free acid and to precipitate one or more impurities selected from iron, aluminum, chromium and silicon, followed by separating as solids, the precipitated impurities and other solids from a first purified solution;
• e) separating copper from the first purified solution with a solvent extraction step to produce a raffinate solution containing the leached nickel and cobalt and reduced in copper and a copper loaded organic phase;
• f) stripping the copper loaded organic phase with an acidic solution to produce a copper loaded solution;
• g) recovering copper from the copper loaded solution with electrowinning;
• h) conducting a second solution purification stage on the raffinate solution from e) by one or both of neutralizing at least a portion of free acid and precipitating one or more impurities selected from iron, aluminum, chromium and silicon, followed by separating as solids, the precipitated impurities and other solids from a second purified solution;
• and
• i) recovering nickel and cobalt as mixed hydroxides or as mixed sulphides from the second purified solution.