A novel low-temperature chlorination roasting technology for simultaneous recovery of valuable metals from spent LiCoO2 cathode material

With the continuous rise of the disposal volume for spent lithium-ion batteries (LIBs), properly recycling spent LIBs has become essential for advancing the circular economy. This study presents a systematic analysis of the chlorination-roasting kinetics and proposes a new two-step chlorination-roasting process for recycling lithium-ion battery cathode materials, integrating thermodynamics. The activation energy for the chloride reaction was determined to be 88.41 kJ/mol based on TG-DTG data using model-free, model-fitting, and Z(α) functions. The results indicated that the reaction was dominated by the First order (F1) model when the conversion rate was below 0.5 and shifted the Second order (F2) model when the conversion rate exceeded 0.5. The effects of roasting temperature, roasting time, and the mass ratio of NH4Cl to LiCoO2 were thoroughly investigated to determine the optimal conditions. Under the optimal parameters of 400°C for 20 minutes with a mass ratio of 3:1 for NH4Cl and LiCoO2, the leaching efficiency of Li and Co reached 99.43% and 99.05%, respectively. Analysis of the roasted products revealed that valuable metals in LiCoO2 transformed into CoCl2 and LiCl. Furthermore, to elucidate the reaction mechanism, providing insights into establishing a novel low-temperature chlorination roasting technology based on a crystal structure perspective. This technology can potentially guide the development of low-energy consumption, low-secondary pollution, high-recovery efficiency, and high-added value processes for LIB recycling.