Patent ID: 8147782

Claim:
A process for producing a purified nickel hydroxide precipitate from a nickel-containing leach solution, the nickel-containing leach solution having impurities including at least one of manganese, copper, zinc, iron and cobalt, so that the nickel hydroxide precipitate is suitable for at least one of pelletization with iron-containing ores and stainless steel production, the process comprising: treating the nickel-containing leach solution under conditions limiting oxygen ingress and with at least one base to form a slurry containing a mixed hydroxide precipitate and a first low-nickel barren solution; thickening and filtering the slurry to form a mixed hydroxide precipitate filter cake; washing the mixed hydroxide precipitate filter cake to remove entrained barren solution; contacting the washed filter cake with acid to dissolve nickel and other metals contained in the mixed hydroxide precipitate filter cake to produce a concentrated nickel-containing solution of higher nickel concentration than in the nickel-containing leach solution; subjecting the concentrated nickel-containing solution to solvent extraction with an organic acidic extractant to remove metals other than nickel from the nickel-containing solution and form a solvent extraction raffinate of purified nickel solution and impurity-loaded organic solution; adding a base to the acidic extractant to maintain a selected pH during the extraction process; stripping the impurity-loaded organic solution with acid to form an impure metal strip solution; treating the solvent extraction raffinate with a base to form a slurry containing purified nickel hydroxide precipitate and a second low-nickel barren solution; thickening and filtering the slurry to form a purified nickel hydroxide precipitate filter cake; washing the nickel hydroxide precipitate filter cake to remove entrained barren solution; drying the nickel hydroxide precipitate filter cake; precipitating the metal impurities from the impure metal strip solution to form an impure metal-containing product; and the process being free of ammonia chemistry.