Simultaneous recovery of zinc and manganese from cadmium-containing mixed-battery leachate by separation and purification process

A study on the simultaneous separation of Zn and Mn from a feed solution containing various types of dissolved battery wastes was carried out by a solvent extraction process using D2EHPA. The selective recovery of Zn and Mn from feed solutions containing Cd ions is difficult due to their similar physicochemical behavior. Therefore, 99.9% of Zn, 99.8% of Mn, and 99.9% of Cd were extracted using the optimum conditions of 40 vol% D2EHPA, 40 vol% NaOH concentration, 2-stage countercurrent extraction, and an O/A ratio of 2. The Co-extracted Co could be scrubbed using pH 2 sulfuric acid at an O/A ratio of 1, and Cd was then scrubbed using 0.5 M Na₂S₂O₃. The results of the Cd scrubbing experiments indicated that the optimum conditions were 3-stage countercurrent scrubbing and an O/A ratio of 2, and the scrubbing efficiency of Cd was approximately 99.9%. The Zn and Mn that remained in the loaded organic could be enriched by increasing the O/A ratio of the stripping stage to 6. From this concentrated solution, high purity zinc manganese sulfate powder, which can be used as a raw material for fertilizer for crop cultivation, was manufactured.