Method for producing high-purity nickel sulfate

The purpose of the present invention is to provide a method for producing a high-purity nickel sulfate with less impurities, especially with less magnesium or less chlorides by regulating the concentration of the extractant and the pH concentration during the processing in a step for obtaining a nickel sulfate solution with high nickel concentration by means of solvent extraction using an acidic organic extractant. A method for producing a high-purity nickel sulfate, which is characterized by processing an acidic solution containing nickel through at least the following steps: a sulfurization step wherein a sulfurizing agent is added into the acidic solution containing nickel, thereby obtaining a sediment of a nickel sulfide and a liquid after sulfurization; a redissolving step wherein a slurry of the nickel sulfide obtained in the sulfurization step is prepared and an oxidant is added into the slurry, thereby obtaining a concentrated solution of nickel; a liquid cleaning step wherein the concentrated solution of nickel obtained in the redissolving step is neutralized by adding a neutralizing agent thereto, thereby obtaining a neutralization sediment and a concentrated solution of nickel after deironization; and a solvent extraction step wherein the concentrated solution of nickel after deironization obtained in the liquid cleaning step is subjected to solvent extraction, thereby obtaining a back extraction liquid and a nickel sulfate solution.