| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for forming cobalt sulfate from an aqueous solution containing cobalt using a solvent extraction method, wherein a cobalt sulfate solution is formed by efficiently separating cobalt even when cobalt is preferentially extracted and an element having a small separation factor is contained.SOLUTION: There is provided a method for producing cobalt sulfate from an aqueous solution containing cobalt and including Ni, Mg, Ca and Na elements as impurity elements, which comprises: (1) an extraction step of extracting cobalt from an aqueous solution containing cobalt using 2-ethylhexyl phosphonic mono-2-ethylhexyl ester which is an organic solvent of phosphonic acid or di-(2,4,4-trimethylpentyl)phosphinic acid which is an organic solvent of phosphinic acid; a washing step of bringing an aqueous cobalt sulfate solution into contact with the organic solvent of phosphonic acid or the organic solvent of phosphinic acid from which cobalt is extracted and distributing and separating Ni, Mg, Ca and Na elements of the impurity elements contained in the organic solvent of phosphonic acid or the organic solvent of phosphinic acid from which cobalt is extracted in the contacted aqueous cobalt sulfate solution; and (3) a back extraction step of back-extracting cobalt with sulfuric acid from the organic solvent of phosphonic acid or the organic solvent of phosphinic acid from which the impurity elements are separated. |
