Recovery of lithium from spent NMC batteries through water leaching, carbothermic reduction, and evaporative crystallization process

The demand for lithium grows exponentially due to its expanding range of applications. Because of their composition, spent lithium-ion batteries represent a promising secondary source of lithium. The present work focuses on a two-stage lithium recovery process applied to two different black masses from NMC 622 electric vehicle batteries after prior crushing and separation stages. In the first stage, hydrolysis is used to extract lithium compounds from the degradation products of the electrolyte (LiPF 6 ). In the second stage, a carbothermic reduction process is carried out in which various reducing agents are evaluated. The result of this stage is a product that is leached with water and crystallised by evaporation. The result of the first stage is two industrially useful compounds: LiF, which is used in the production of lithium-ion battery electrolytes, and Li 3 PO 4 , which is used in the production of lithium-iron-phosphate batteries. In the second stage, Li 2 CO 3 is recovered with a remarkably low LiF content, with a purity higher than 98.4 %. This process allows 90–94 % of the total lithium in the black mass to be recovered. • A double-steps procedure was carried out to recover lithium from LIBs. • Black masses from spent NMC batteries were used as a promising secondary source. • Recovered materials (Li 2 CO 3 , LiF and Li 3 PO 4 ) can be used industrially. • This process allows to recover 90–94 % of the total lithium from NMC batteries.