Thermal Processing of Spent Li-Ion Batteries for Extraction of Lithium and Cobalt-Manganese Values

Lithium-ion batteries have a limited lifespan and ever-growing demand, and the presence of critical metals such as lithium, cobalt and manganese are key factors for their recycling. In this study, discarded mixed mobile batteries were discharged, dismantled and separated into cathode and anode sheets followed by crushing in an attritor. The cathode material contained LiCoO2 and LiMn2O4 of around 65.8 and 34.2%, respectively, while graphite was present in the anode material. The cathode material was reduced using graphite in a muffle furnace at different residence time and dosage. A Box-Behnken statistical design was employed for optimization of reduction parameters. The reduced mass was dissolved in distilled water, and resulting leach residue was magnetically separated. The obtained magnetic fraction contained cobalt and manganese oxide, whereas graphite and lithium carbonate were found in nonmagnetic fraction and dried solution. The overall yield of the process was 74.08%, and final product composition was Co 64.2 and MnO 35.8%, respectively. Further, the product was cleaned using planetary ball milling for 10 min followed by magnetic separation cleaning to recover concentrate with 83% Co values.