A comprehensive review of whole process typical hydrometallurgical technologies for recycling waste lithium-ion batteries

Some studies have reviewed the different waste lithium-ion batteries (LIBs) recycling methodologies by hydrometallurgy, but whole process was not discussed comprehensively, especially few compared analysis of some typical technologies which are commonly used in commercial production. This paper presents a review on the typical approaches for recycling critical materials from waste LIBs by hydrometallurgy. The whole recovery process is divided into pretreatment, leaching, purification and regeneration. For pretreatment, discharge and materials separation are mainly discussed, which is important for granting the safety and efficiency of subsequent steps. Concerning leaching, inorganic acid leaching, organic acid leaching and alkali leaching are showed, in which the most widely used is inorganic acid leaching, it can extract metallic elements efficiently with reductants cooperation or electrochemical and acid gas assisted leaching. As to purification, it is performed by solvent extraction, chemical precipitation and ion exchange, these three methods are broadly used and quite mature in practical industrial production. As for regeneration, it is related to the quality of reborn products, the sol-gel and co-precipitation have representational significance during battery materials reproduced. The analysis of arguments including technical effect, economical cost and environmental impact are revealed by comparing different technologies. The challenges and perspectives are also proposed to further perfect the available hydrometallurgical technologies. The purpose of this review is to demonstrate the latest research advances of hydrometallurgical process and provide scientific references for techniques-choosing in commercial production, which is helpful to select green, efficient and economic recycling processes during industrial production of waste LIBs recycling.