| 摘要 |
Provided is a method for producing cobalt sulfate, wherein high purity cobalt sulfate is obtained by effectively eliminating impurities in a process for obtaining a cobalt sulfate solution with a high cobalt concentration by solvent extraction using an acidic organic extractant. Disclosed is a method in which, on the occasion of separating an acidic solution containing calcium, magnesium and sodium as impurities from a cobalt chloride solution by solvent extraction, when a diluent is added to the extractant to be used to dilute the extractant to a concentration of 10% to 30% by volume, and preferably 15% to 25% by volume; in Step 1, the operational pH is maintained in the range of 4.0 to 5.0 and the liquid volume ratio of organic phase/liquid phase is maintained in the range of 5.0 to 7.0; in Step 2, the operational pH is maintained in the range of 4.0 to 4.5 and the liquid volume ratio of organic phase/liquid phase is maintained in the range of 5.0 to 10.0; and in Step 3, the pH is maintained in the range of 0.5 to 1.0, the concentration ratios of calcium, magnesium and sodium with respect to the cobalt concentration in the cobalt sulfate solution thus obtainable are reduced to 0.0001, 0.0001, and 0.00005 or less, respectively. (213 words) |
