A combined process for cobalt recovering and cathode material regeneration from spent LiCoO₂ batteries: Process...

A combined process has been developed for recovering cobalt and regenerating cathode material from leach liquor of spent LiCoO₂ batteries. Cobalt of 98% can be selectively separated from leach liquor using ammonium oxalate of 1.15 (mole ratio) at pH of 2.0, 55 °C, and 40 min. Kinetics analysis indicates that precipitation of cobalt is controlled by a combination of surface chemical reaction and diffusion. The E_a value of precipitation is 19.68 kJ/mol obtained from the second-order model of (1 - a)^-1 = k't + c. Based on the TG/DSC curves of oxidation of cobalt oxalate, it is found that formation of Co₃O₄ oxidized from cobalt oxalate is in according with the model of randomly nucleating followed by nucleus growth. The E_a value is 84.93 kJ/mol that is provided by the suitable model of g(α) = [-ln(1 - α)]^1/3. Then, lithium is recovered from the filtrate as Li₂CO₃ with the purity of 99.5% by precipitation method. Finally, new cathode material with a good electrochemical performance is regenerated using obtained Co₃O₄ and lithium carbonate through solid phase method.