Selective Lithium Extraction via Chlorination Roasting and Subsequent Valuable Metal Leaching from Spent Lithium-Ion Batteries

The rapid growth of the electric vehicle (EV) market has highlighted the critical importance of securing a stable supply chain for lithium-ion battery (LIB) resources, thereby increasing the need for efficient recycling technologies. Among these, lithium recovery remains a major challenge due to significant losses during conventional processes. In this study, a chlorination roasting process was introduced to convert Li2O in spent LIBs into LiCl, which was subsequently evaporated for selective lithium extraction and recovery. Roasting experiments were conducted under air, vacuum, and N2 conditions at 800–1000 °C for 1–5 h, with Cl/Li molar ratios ranging from 0.5 to 8. The optimal condition for lithium evaporation, achieving 100% recovery, was identified as 1000 °C for 5 h, with a Cl/Li molar ratio of 6 under vacuum. Following lithium removal, residual valuable metals were extracted through H2SO4 leaching, and the effects of acid concentration and H2O2 addition on leaching efficiency were examined. The air-roasted samples exhibited the highest leaching performance, while the vacuum- and N2-roasted samples showed relatively lower efficiency; however, the addition of H2O2 significantly enhanced leaching yields in these cases.