Method for leaching nickel from nickel matte

A method of leaching nickel from a sulfidic nickel-copper matte containing nickel, copper, and iron wherein said matte is pressure leached with copper sulfate at a temperature above the ambient temperature of said matte feed up to about 160° C. to produce a slurry containing a nickel sulfate bearing solution and a precipitate of digenite which is oxidized to copper sulfate in two stages, and also leaching an essentially metallic copper-nickel matte with sulfuric acid to produce a precipitate and a solution containing nickel- and copper sulfate and sulfuric acid which solution is conducted to a second oxidation stage of the pressure leaching cycle.

A method of leaching nickel from a sulfidic nickel-copper matte wherein said matte is pressure leached in an autoclave with copper sulfate in one stage at a temperature above the ambient temperature of said matte feed up to about 160° C. to produce a slurry containing a precipitate of digenite and a nickel- and copper-bearing solution, wherein the amount of copper sulfate solution used is in excess to the amount of nickel present in the pressure leach.

A method of leaching nickel from a sulfidic nickel-copper matte wherein said matte is pressure leached in an autoclave with copper sulfate at a temperature above the ambient temperature of said matte feed up to about 160° C. to produce a slurry containing a precipitate of digenite and a nickel- and copper-bearing solution wherein said nickel-copper matte is cooled rapidly prior to leaching.