China Nonferrous Metallurgy

The crude nickel sulfate produced in the process of recovering nickel from copper electrolyte has the problem of high impurity content, resulting in a low added value of the crude nickel sulfate, thus, requiring a secondary impurity removal. A copper smelting enterprise used P204 to carry out an extraction and impurity removal process test on crude nickel sulfate solution, and optimized and improved the issues of high nickel loss rate and serious emulsification in the test with excellent results. The P204 extractant was saponified with sodium hydroxide, and the sodium soap was used for extraction of the crude nickel sulfate solution. The extraction rates of iron and zinc were all above 99.9%, and the nickel loss rate was 12.26%. In the saponification process of P204, the loss of nickel could be decreased by converting sodium soap into nickel soap. When nickel soap was used for extraction of the crude nickel sulfate solution, the extraction rates of iron and zinc were still above 99.9%, and the loss rate of nickel was lowered to 0.4%. The emulsification issue in the extraction process can be solved by controlling and purifying the crude nickel sulfate solution and controlling the pH value of the feed solution.