China Nonferrous Metallurgy

The carbon thermal reduction-leaching method was proposed to extract valuable metals from spent lithium-ion batteries, and the change of metal valence, leaching activation energy and leaching rate were systematically investigated. The results showed the best roasting conditions as below, roasting temperature 650℃, roasting time 2.0h and carbon addition amount 10 wt%. And the optimal leaching conditions were 3mol/L H2SO4, leaching temperature 60℃, solid-liquid ratio 100g/L and reaction time 90min. The leaching rates of Li, Ni, Co and Mn were up to 93.10%, 98.91%, 99.34% and 99.26%. The activation energies of Ni, Co and Mn were 40.09kJ/mol, 41.04kJ/mol and 14.30kJ/mol, respectively. Compared with the traditional acid leaching method, carbothermal reduction greatly enhances the leaching rate of Ni, Co and Mn with the reduced leaching activation energy, making it easier to leach valuable metals from waste lithium ion batteries.