Recovery of Cobalt as Cobalt Sulfate from Discarded Lithium-Ion Batteries (LIBs) of Mobile Phones

Abstract

Cobalt, an exceptional cathode material present in lithium-ion batteries (LIBs), is an essential element for the production of energy storage devices. But, the lifespan of rechargeable batteries is decreasing day-by-day, which become obsolete after reaching their end of life. Therefore, an enormous amount of discarded LIBs are generated. Keeping in mind the above, a novel approach has been made to selectively recover cobalt from sulfate leach liquor of discarded LIBs containing 1.4 g/L Cu, 1.1 g/L Ni, 11.9 g/L Co, 6.9 g/L Mn, and 1.2 g/L Li. Initially, Cu and Ni were extracted by solvent extraction techniques using 10% LIX 84-IC. Almost complete precipitation of cobalt occurred from leach liquor at pH ~3 using ammonium sulfide solutions. Cobalt from the precipitated product was further dissolved in H2SO4 in presence of H2O2 at elevated temperature. The leach liquor obtained was evaporated to get the cobalt sulfate with a purity of more than 98%.