PRODUCTION METHOD OF HIGH PURITY COBALT CHLORIDE AQUEOUS SOLUTION

摘要

To provide an efficient production method of a high purity cobalt chloride aqueous solution of a low Mg concentration.SOLUTION: The production method of a high purity cobalt chloride aqueous solution is comprised of a solvent extraction step S1 and solution cleaning steps S2-S4. The solvent extraction step S1 is comprised of an extraction stage S11 of mixing an amine-based extraction agent in a nickel chloride aqueous solution containing Co and MG and thus extracting Co into an organic phase to obtain a nickel chloride aqueous solution without Co, a washing stage S12 of washing the organic phase with a washing fluid, and a back extraction stage S13 of back extracting the organic phase after the washing to obtain a crude cobalt chloride aqueous solution. In the solution cleaning steps S2-S4, impurities are removed by adding cobalt carbonate slurry or the like to a mixture of the crude cobalt chloride aqueous solution and the cobalt chloride aqueous solution containing Mg. The high purity cobalt chloride aqueous solution obtained in the solution cleaning steps S2-S4 is supplied to an electrolysis step S5. An electrolysis waste solution discharged from the electrolysis step S5 is distributed to a solution for the washing fluid, a solution for a raw material for producing the cobalt carbonate, a solution for repulping the produced cobalt carbonate, and a solution to be concentrated by evaporation for feeding to the electrolysis step.SELECTED DRAWING: Figure 1