Preparation of Cobalt Sulphate From Cobalt-residue by Activating Roasting-Leaching With Sulfuric Acid-Solvent Extraction Process

A new process for extracting cobalt sulphate from cobalt-residue was developed.The process was consisted of activating roasting of cobalt residue-leaching of cobalt using sulfuric acid-solvent extraction for separating cobalt from impurities.The optimal parameters were determined by experiments.The result showed that the optimal parameters were roasting temperature of 900℃,activating agent addition of 2∶1(mass ratio of activating agent to cobalt residue),roasting time of 1 hour and ratio of liquid volume to solid mass of 5∶1,sulfuric acid concentration of 200 g/L and leaching temperature of 90℃.Under the optimal conditions,the leaching ratio of Co was of 98.8%.The impurities in the leaching solution was removed with P204 solvent extraction,and cobalt from nickel was separated by P507 solvent extraction.The cobalt sulphate solution was following evaporated to obtain pure cobalt sulphate complying with national standards HG3-914-78.