Purification of Li2CO3 obtained through pyrometallurgical treatment of NMC black mass from electric vehicle batteries

The recycling of lithium batteries is essential for a sustainable energy transition. However, impurities in the products obtained from the black mass can lower their market value. In this work, lithium carbonate, which has the highest market share among lithium-based products, is purified using distilled water at controlled temperature, time and stirring speed. The purification process involves dissolving lithium carbonate in distilled water at low temperatures (between 0 and 10°C), followed by crystallization through water evaporation. Optimal conditions yielded lithium carbonate with a purity of 99.66% after two stages of purification. The dependence of the variables on the final purity was deeply analyzed and the thermodynamics of the reaction was studied, confirming the exothermic nature the dissolution reaction.