Separation of Al and Cu from spent LiFePO4 cathodes via a combination of selective leaching and two-stage precipitation

Recycling Li, P and Fe from cathodes of spent LiFePO 4 batteries plays a significant role in mitigation of Li resources shortage, as well as environmental protection. In this study, black mass from spent LiFePO 4 batteries were subjected to roasting at 600 °C under a nitrogen atmosphere to inhibit the oxidation of Fe 2+ . Then, Li, Fe and P in the black mass were successfully leached into the solution under optimal conditions (2 mol/L H 2 SO 4 , liquid to solid ratio of 10:1, temperature of 35℃, 300r/min stirring for 120 min), that achieved the initial separation of these elements from graphite and part of Al. Subsequently, a two-stage precipitation process, consisting of a cementation reaction followed by pH value adjustment, was employed to sequentially remove Cu and Al from the leaching solution. The total separation efficiencies for Cu and Al achieved 99.93 % and 95.37 % (based on contents of black mass), respectively. After separation of Cu and Al, 96.03 % of Li and 83.69 % of P present in the black mass were successfully recovered in the forms of Li 2 CO 3 and FePO 4 , respectively. The strategy developed herein provides valuable guidance for the resource utilization of P, Fe and Li, demonstrating promising potential for industrial-scale applications.