Separation of Cobalt and Lithium from Chloride and Sulfate Solutions by Solvent Extraction

Abstract

The lithium ion secondary batteries (LIBs) are widely used as electrochemical power sources in modern-life appliances and the usage of LIBs has rapidly increased. Recycling of LIBs has increasingly become important because their safe disposal may become a serious problem due to the presence of flammable and toxic elements or compounds although spent LIBs are not generally classified as dangerous waste and at the same time, some economic benefits could be achieved in recovery of major components from LIBs. Since spent LIBs represent a valuable waste material for recovery of metals or compounds, recycling of spent batteries may result in economic benefits. The extraction and separation of Co and Li by solvent extraction using D2EHPA and EHPNA (PC-88A) as extractant alone and in combination with TOA and TBP from chloride and sulfate solutions were investigated to obtain the fundamental data for the hydrometallurgical treatment of the spent lithium ion secondary batteries. From this study, the extractant combination, EHPNA/TOA, is favorable to the separation of Co and Li from chloride and sulfate solutions compared with other extractants tested in this study. It was also found that the separation efficiency of Co and Li with EHPNA/TOA from chloride solution was better than that from sulfate solution.