SOLUTION PURIFICATION METHOD OF COBALT CHLORIDE SOLUTION

摘要

PROBLEM TO BE SOLVED: To provide a solution purification method of a cobalt chloride solution with a good operation rate.SOLUTION: In removing impurities as sulfide precipitation by adding a sulfurization agent to a cobalt chloride solution containing at least copper as an impurity, a sodium hydrosulfide solution of a concentration of 30-100 g/L is used as a sulfurizing agent. Use of a sodium hydrosulfide solution as a sulfurization solution eliminates the need of switching of a cylinder, unlike hydrogen sulfide gas, leading to improvement of the operation rate. Since the concentration of the sodium hydrosulfide is 30-100 g/L, preferential sulfurization of cobalt due to occurrence of a local high-pH region produced by contact with the cobalt chloride solution can be prevented.