Metal extraction and recovery from cathode material of spent lithium-ion batteries utilizing an organic acid reagent scheme

This study focuses on using a green reagent scheme of methanesulfonic acid (MSA) and citric acid (CA) to extract valuable metals from the cathodes, aiming to minimize environmental impact during the recycling process. Leaching studies on LiCoO₂ identified optimal conditions as follows: 2.4 mol/L MSA, 1.6 mol/L CA, S/L ratio of 80 g/L, leaching temperature of 90°C and leaching time of 6 h. The maximum Co and Li extraction achieved was 92% and 85%, respectively. LiCoO₂ dissolution in MSA-CA leaching solution is highly impacted by temperature; Avrami equation showed a good fitting for the leaching data. The experimental activation energy of Co and Li was 50.98 kJ/mol and 50.55 kJ/mol, respectively, indicating that it is a chemical reaction-controlled process. Furthermore, cobalt was efficiently recovered from the leachate using oxalic acid, achieving a precipitation efficiency of 99.91% and a high-purity cobalt oxalate product (99.85 wt.%). In the MSA-CA leaching solution, MSA served as a lixiviant, while CA played a key role in reducing Co in LiCoO₂. The overall organic acid leaching methodology presents an attractive option due to its reduced environmental impact. (Figure presented.)