Kinetics of metals dissolution from EV batteries for the development of sustainable technology

Abstract

The increasing volume of scrap EV batteries generated globally poses significant challenges for disposal and recycling due to stringent environmental concerns. Recycling these batteries not only mitigates environmental pollution but also enables the recovery of valuable metals. This paper investigates the leaching kinetics of metals in the black mass of EV batteries, a crucial step in battery recycling. The black mass was separated from discarded EV batteries using chemical and mechanical pre-treatment processes. Systematic leaching studies were carried out to observe the dissolution behavior of various metals by varying parameters such as leachant concentration, reductant volume, agitation speed, pulp density, temperature, and time. Maximum dissolution (∼99.99 %) of Ni, Co, Li, Mn, and Cu were achieved using 3 % H₂SO₄ (v/v) and 10 % H₂O₂ (v/v) after 2 h at 75 °C, with a pulp density of 100 g/L and an agitation speed of 400 rpm. Leaching kinetics for Mn, Co, and Cu followed a chemical reaction control dense contant size and shrinking spheres model, (1 − (1 − X)^1/3 = k_ct), while Li and Ni followed a chemical reaction control dense constant-size cylindrical particles model (1 − (1 − X)^1/2 = k_ct), validated by SEM results. The activation energy for Li and Ni were 15.55 kJ/mol and 24.65 kJ/mol, respectively, while Mn, Co, and Cu had activation energyof 22.72 kJ/mol.