The present invention provides a process for preparing a high-purity nickel sulphate solution, comprising the steps of: i. providing an aqueous feed solution comprising nickel, cobalt, calcium and magnesium: ii. extracting cobalt, calcium, and partly magnesium from said aqueous feed solution using a first solvent comprising a first alkylphosphorus-based acidic extractant, thereby obtaining an aqueous raffinate comprising nickel and magnesium: iii. extracting magnesium from said aqueous raffinate solution comprising nickel and magnesium using a second solvent comprising a second alkylphosphorus-based acidic extractant, thereby obtaining a high-purity aqueous nickel sulphate solution comprising nickel and magnesium: iv. stripping the first loaded solvent comprising cobalt, calcium and magnesium with an aqueous solution comprising a mineral acid.

The present invention provides a process for preparing a high-purity nickel sulphate solution, comprising the steps of: i. providing an aqueous feed solution comprising nickel, cobalt, calcium and magnesium: ii. extracting cobalt, calcium, and partly magnesium from said aqueous feed solution using a first solvent comprising a first alkylphosphorus-based acidic extractant, thereby obtaining an aqueous raffinate comprising nickel and magnesium: iii. extracting magnesium from said aqueous raffinate solution comprising nickel and magnesium using a second solvent comprising a second alkylphosphorus-based acidic extractant, thereby obtaining a high-purity aqueous nickel sulphate solution comprising nickel and magnesium: iv. stripping the first loaded solvent comprising cobalt, calcium and magnesium with an aqueous solution comprising a mineral acid.

This application pertains to methods of recovering metals from metal sulfides that involve contacting the metal sulfide with an acidic sulfate solution containing ferric sulfate and a reagent that has a thiocarbonyl functional group, wherein the concentration of reagent in the acidic sulfate solution is sufficient to increase the rate of metal extraction relative to an acidic sulfate solution that does not contain the reagent, to produce a pregnant solution containing the metal ions.

This application pertains to methods of recovering metals from metal sulfides that involve contacting the metal sulfide with an acidic sulfate solution containing ferric sulfate and a reagent that has a thiocarbonyl functional group, wherein the concentration of reagent in the acidic sulfate solution is sufficient to increase the rate of metal extraction relative to an acidic sulfate solution that does not contain the reagent, to produce a pregnant solution containing the metal ions.