Leaching Kinetics of Valuable Metals from Calcined Material of Spent Lithium-Ion Batteries

This study aimed to investigate the leaching kinetics of valuable metals contained in the calcined black mass derived from the incineration of spent lithium-ion battery (LIB) modules. The effects of sulfuric acid (H₂SO₄) concentration (0.5-3 M), hydrogen peroxide (H₂O₂) concentration (0.5-2.0 vol %), solid/liquid (S/L) ratio (25-75 g/L), leaching time (10-120 min), and leaching temperature (30 °C-70 °C) on metal leaching efficiency from black mass were investigated. The optimal leaching conditions were achieved with 1 M H₂SO₄, 1 vol % H₂O₂, and a S/L ratio of 50 g/L at 60 °C for 60 min. Under these conditions, Li, Ni, and Mn had leaching efficiencies of 100%, with Co at 97.17%, respectively. An investigation of the leaching kinetics utilizing H₂O₂ as an additive revealed that the Avrami model fits the metal leaching process. The results of this study suggested that diffusion and surface chemical reactions controlled the leaching mechanisms of these metals, with activation energies of 7.829, 5.646, and 5.077 kJ mol^-1 for Li, Ni, and Co, respectively.