Processing of LCO LIBs Leachates—Part I: Removal of Accompanying Metals and Monitoring Losses of Co and Li

This study investigates the hydrometallurgical purification of the acidic leachate from spent LiCoO2-based lithium batteries, focusing on the selective removal of Cu, Mn, and Ni while monitoring co-precipitation of Fe and Al and minimizing Co and Li losses. Thermodynamic modelling using HSC Chemistry 10 and Hydra/Medusa guided the design of precipitation conditions. The optimal Cu precipitation was achieved using Na2S (Na2S:Cu = 4:1, 20 °C, 5 min, 300 rpm), yielding > 99% removal. Mn was efficiently precipitated as MnO2 using KMnO4 (KMnO4:Mn = 1:1, 20 °C, pH ≈ 2, 10–15 min, ≈97% efficiency). Ni was recovered as [Ni(DMG)2] under DMG:Ni = 5:1, 80 °C, 15 min, pH ≈ 5, achieving ≈99% removal. Sequential 2 L experiments (precipitation order: Cu → Mn → Ni) validated the scalability of the process. Cu and Ni removal remained high (>95%), while Mn efficiency slightly decreased (≈91%) due to kinetic and redox inhomogeneity. No significant precipitation of Co and Li was observed, leaving them in solution and concentrating from 12.9 to 18.8 g·L−1 and 2.71 to 3.50 g·L−1, respectively, with total losses of <1%. The resulting CuS, MnO2, and [Ni(DMG)2] precipitates exhibited moderate purity (46–63%) but represented valuable secondary raw materials. Overall, sequential precipitation under optimized conditions demonstrates robust, selective removal of accompanying metals while concentrating Co and Li, providing an efficient and scalable route for LIBs leachate valorisation.