绿色矿冶

The impurity content of raw materials in the wet nickel refining production line of a factory is high, especially the content of calcium and magnesium. With the increase of processing capacity, calcium and magnesium are enriched in the follow-up system to achieve saturated precipitation crystallization, which affects the stable operation of the production line. On the basis of summarizing and comparing the common methods of removing calcium and magnesium, such as chemical precipitation method, concentration static method, ion exchange method and extraction method, combined with the existing extraction process, this paper used P204 extractant to carry out multi-stage countercurrent extraction of nickel sulfate solution, and analyzed the extraction effect of P204 under different pH values and different feed concentration conditions. The results showed that when P204 was used to extract C272 raffinate, the extraction rate of calcium showed a fluctuating upward trend with the increase of extraction stages, and reached the maximum after six-stage countercurrent extraction. The extraction rate of magnesium increased steadily with the increase of the number of stages, and remained about 98% after ten-stage countercurrent extraction. Under the same experimental conditions, the lower the pH value, the higher the extraction rate of calcium and magnesium ions, and the lower the extraction rate of iron and cobalt ions. When the nickel ion in the solution was high, nickel was precipitated before calcium and magnesium during P204 extraction, and the nickel removal rate was high. The solution was viscous after the reaction and the filtration performance was poor. Therefore, the extraction of the solution with higher nickel ions does not have practical significance.