METHOD FOR PRODUCING HIGH-PURITY NICKEL SULFATE

摘要

Provided is a production method for obtaining high purity nickel sulfate having low levels of impurities, particularly low levels of magnesium and chloride, by adjusting the concentration of an extractant and the pH concentration at the time of treatment in a process of obtaining a nickel sulfate solution having a high nickel concentration by solvent extraction using an acidic organic extractant. The method includes treating an acidic solution containing nickel through at least the following steps of: a sulfurization step of adding a sulfurizing agent to the acidic solution containing nickel, and obtaining a precipitate of nickel sulfide and a solution after sulfurization; a redissolution step of preparing a slurry of the nickel sulfide obtained in the sulfurization step, adding an oxidizing agent to the slurry, and thereby obtaining a concentrated solution of nickel; a solution purification step of subjecting the concentrated solution of nickel obtained in the redissolution step to neutralization by addition of a neutralizing agent, and thereby obtaining a neutralized precipitate and a concentrated solution of nickel after iron removal thus produced; and a solvent extraction step of subjecting the concentrated solution of nickel after iron removal obtained in the solution purification step, to solvent extraction, and obtaining a stripped liquid and a nickel sulfate solution.