Transfer of Early-Stage Lithium Recovery from Laboratory-Scale Water Leaching to Upscale Challenges

The early-stage lithium recovery (ESLR) process associates thermal treatment of the black mass from lithium-ion batteries (LIB) with subsequent leaching, especially with water, targeting Li recovery in the first step of the process chain as lithium carbonate. The validation of ESLR has resulted in high Li efficiencies; however, currently, researchers have not yet been established the optimum parameters, which brings uncertainties to a further upscale. Based on that, four parameters, including different black masses previously thermally treated in the industry, were investigated in a leaching step in laboratory scale targeting Li and F leaching efficiencies. Through ANOVA statistical analysis, regression equations of the leaching efficiencies for both elements were generated, which supports an optimization study. The optimum parameters were then transferred to an upscale 100 L leaching trial and evaluated. The results in laboratory scale showed that Li maximization and F minimization were achieved at an S/L ratio of 30 g/L, 80 °C, and 6 L/min of CO2 gas addition, as well as with a sample of bigger particle size and probably more efficient thermal treatment. However, the upscale result with the same parameters showed a lower Li leaching efficiency, which is related to the poor geometric similarity between laboratory and upscale reactors.