A green process to recover valuable metals from the spent ternary lithium-ion batteries

• A green acid-leaching process is developed to recover valuable metals. • The application of the reagent regime can greatly reduce environmental pollution. • The acid-leaching mechanism has been preliminarily studied. • Kinetic analysis is performed to better understand the leaching process. The traditional inorganic acid leaching method for recycling spent ternary lithium-ion batteries (NCM) materials presents serious environmental pollution and unsafe problems. In this study, a green leaching process for recovering valuable metals from the spent NCM materials using dl -malic acid as the leaching agent and glucose as the reductant is developed, and systematicalsly investigates the leaching kinetics and interface reaction. The results suggest that the leaching efficiencies of Ni, Co, Mn, and Li reach 90.14 %, 90.58 %, 98.66 %, and 98.53 %, respectively, under the optimal conditions of 1 mol/L dl -malic acid, 0.5 g/g glucose, 90℃ leaching temperature, and 25 g/L pulp density for 120 min. The apparent activation energies for leaching of Ni, Co, Mn, and Li are determined as 55.45, 76.08, 39.42, and 42.09 kJ/mol, respectively, indicating that the surface chemical reaction is the rate-controlling step during this leaching process. This process can be an environmentally friendly alternative method to recover valuable metals from spent NCM.