Abstract: A method for the optimisation of feed for downstream processing includes passing a sulphide ore concentrate to a first leach step, in which a leach discharge slurry is produced, passing an intermediate product to a second leach step, in which a pregnant leach solution is produced, and combining the leach discharge slurry of the fist leach step with the intermediate product in the second leach step. Residual acid generated in the first leach step is used to leach the intermediate product in the second leach step and provides the pregnant leach solution containing one or more target metals.

Abstract: A method for preparing high-purity mixed nickel and cobalt sulphate, the method comprising the recovery of nickel and cobalt sulphate crystals from an organic phase rich in both nickel and cobalt by way of contacting the nickel and cobalt rich organic phase with an aqueous strip solution of sufficient H2SO4 concentration to extract nickel and cobalt from the organic phase and of sufficient Ni2+ and Co2+ concentration to precipitate nickel and cobalt sulphate crystals and form a nickel and cobalt lean organic phase. Also disclosed is a method for the optimisation of feed for downstream processing.

Abstract: A method for recovering NiSO4.6H2O crystals from a nickel rich organic phase is provided. The method includes contacting a nickel rich organic phase with an aqueous strip solution of sufficient H2SO4 concentration to extract nickel from the organic phase and of sufficient Ni2+ concentration to precipitate NiSO4.6H2O crystals and form a nickel lean organic phase. Also provided are methods for recovering NiSO4.6H2O crystals that include preceding processing steps, including low temperature pressure oxidation (LTPOX) autoclaving of a nickel sulphide concentrate to afford a pregnant leach solution (PLS).