Study of the Process of Lithium Leaching from Black Mass of Spent Lithium-Ion Batteries Using the Method of Regression Analysis

Abstract— The process of lithium dissolution (leaching) from the “black mass” obtained from spent lithium-ion batteries in aqueous solutions of sulfuric acid with the addition of hydrogen peroxide as a reducing agent was studied using the regression analysis method. The concentration of sulfuric acid, the concentration of hydrogen peroxide, and the duration of the leaching process at a solution temperature of 70°C were considered as input factors. Regression equations were obtained and the adequacy of the used mathematical model of the black mass leaching process was tested. The composition range of the lithium leaching solution was established in which the maximum extraction of lithium (54 mM) occurs at a solution temperature of 70°C in 100–120 min: 2.5–4.0 M H2SO4 and 2–3% H2O2.