Advances in Glycine–Ammonia Leaching for the Sustainable Recovery of Critical Raw Materials from Thermally Treated Black Mass

The growing demand for electric and hybrid vehicles with lithium-ion batteries has made the development of sustainable recycling process for the recovery of critical raw materials from spent batteries necessary. Our main objective is to study the use of sustainable leaching solutions based on glycine and glycine/NH3 for the recovery of Li, Co, Ni, and Cu from thermally treated black mass. The process variables studied in this research (time, temperature, and solid/liquid ratio) have a significant influence on the extraction percentages of Ni, Co, Li, and Cu. Due to the alkaline nature of the black matter, additional pH adjustments are not necessary, as glycine alone achieves a pH greater than eight, suitable for the formation of metal–glycine and metal–NH3 complexes. At 80 °C using glycine/NH3 solutions, it is possible to recover 99% of Cu, 92.4% of Ni, 78.4% of Co, and 76.5% of Ni.