Patent ID: 8580213

Claim:
A method for recovering nickel from a sulfuric acid aqueous solution containing nickel and cobalt, and impurity elements including iron, aluminum, manganese, characterized by comprising the following steps (1) to (5); step (1): by adding calcium carbonate into the sulfuric acid aqueous solution, under blowing mixed gas composed of sulfurous acid gas and air or oxygen gas, to subject the solution to oxidation neutralization treatment, and to remove a precipitate (a) containing iron and aluminum generated; step (2): by adding calcium hydroxide to the solution after the oxidation neutralization treatment obtained in the step (1), to subject the solution to neutralization treatment, and to separate and recover mixed hydroxides containing nickel and cobalt; step (3): by subjecting the mixed hydroxides obtained in the step (2) to dissolution treatment in a sulfuric acid solution having a concentration of equal to or higher than 50% by mass, to remove a precipitate (b) containing manganese and gypsum generated, and to obtain a concentrated solution of nickel and cobalt; step (4): by subjecting the concentrated solution obtained in the step (3) to solvent extraction treatment, using a phosphate ester-based acidic extraction agent, to obtain an extraction residual liquid containing nickel and a back extraction liquid containing cobalt; step (5): by adding a neutralizing agent to the extraction residual liquid obtained in the step (4), to subject the solution to the neutralization treatment, and to separate and recover nickel hydroxide generated.