Low-temperature chlorination roasting technology for the simultaneous recovery of valuable metals from spent LiCoO_(2)cathode material

With the continuous increase in the disposal volume of spent lithium-ion batteries(LIBs),properly recycling spent LIBs has become essential for the advancement of the circular economy.This study presents a systematic analysis of the chlorination roasting kinetics and proposes a new two-step chlorination roasting process that integrates thermodynamics for the recycling of LIB cathode materials.The activation energy for the chloride reaction was 88.41 kJ/mol according to thermogravimetric analysis–derivative thermogravimetry data obtained by using model-free,model-fitting,and Z(α)function(αis conversion rate).Results indicated that the reaction was dominated by the first-order(F1)model when the conversion rate was less than or equal to 0.5 and shifted to the second-order(F2)model when the conversion rate exceeded 0.5.Optimal conditions were determined by thoroughly investigating the effects of roasting temperature,roasting time,and the mass ratio of NH_(4)Cl to LiCoO_(2).Under the optimal conditions,namely 400℃,20 min,and NH_(4)Cl/LiCoO_(2)mass ratio of 3:1,the leaching efficiency of Li and Co reached 99.43% and 99.05%,respectively.Analysis of the roasted products revealed that valuable metals in LiCoO_(2)transformed into CoCl_(2) and LiCl.Furthermore,the reaction mechanism was elucidated,providing insights for the establishment of a novel low-temperature chlorination roasting technology based on a crystal structure perspective.This technology can guide the development of LIB recycling processes with low energy consumption,low secondary pollution,high recovery efficiency,and high added value.