Li-Ion Battery Recycling via High-Intensity Milling Followed by Organic Acid Leaching for Preferential Lithium Extraction

Nowadays, spent batteries are considered a secondary and potential resource to meet the growing demand for lithium, a critical element widely used in the manufacturing of electric vehicles. Therefore, this work presents a hydrometallurgical method for extracting lithium from Nickel–Manganese–Cobalt (NMC) batteries. Citric (C6H8O7) and oxalic (C2H2O4) acids were used as leaching agents, both of which are cataloged as environmentally friendly organic compounds. To comprehend the chemical interactions between citrate (cit), oxalate (ox) and metallic ions, a thermodynamic analysis is presented. According to this analysis, both ions were effective in dissolving lithium; however, the experimental studies demonstrated that oxalate ensured a selective process and achieved complete lithium dissolution under the experimental conditions 1 M C2H2O4, 50 g/L, 60 °C, and 60 min, with a mechanically treated sample (milling time 8 min at 1000 rpm). In this process, the other metals present in the sample, such as cobalt, nickel, and manganese, formed insoluble species with oxalate, allowing their recovery in subsequent stages. Therefore, this investigation provides a proficient methodology for battery recycling, emphasizing sustainable practices.