Lithium Recovery from NCM Lithium-ion Battery by Carbonation Roasting with Graphite Followed by Water Leaching

Abstract

Owing to the demand for lithium-ion batteries, the recovery of valuable metals from waste lithium-ion batteries is required in future. A pyrometallurgical treatment is appropriate for recycling a large number of waste lithium-ion batteries, but Li loss to slag and dust present a significant challenge. This research investigated carbonation roasting and water leaching behaviors in Li-ion batteries by graphite addition to recover Li from the NCM-based cathode materials of waste Li-ion batteries. When 10 wt% of graphite was added, CO and CO 2 gases were emitted with a rapid weight reduction at apporoximately 850 K, when heated in Ar and CO 2 atmosphere. After the rapid weight reduction, NCM was decomposed and reduced to metal oxides and pure metals. In the carbonation roasting of black powder (NCM+graphite), O 2 is generated via the decomposition of NCM, and an oxides, such as Li 2 O and NiO were were also generated. Subsequently, Li 2 O reacts with CO 2 to generate Li 2 CO 3 , and a part of NiO was reduced by graphite to produce metal Ni. In addition, up to 94.5 % Li 2 CO 3 with ~99.95 % purity was recovered via water leaching after carbonation roasting.