Roasting-Water Leaching-Slag Cleaning Process for Recovery of Valuable Metals from Li-ion Battery Scrap

Abstract Waste lithium-ion batteries (LIBs) are important secondary sources of valuable materials, including Critical Raw Materials (CRMs) like lithium, cobalt, manganese, and graphite, as defined by the European Union (EU). LIBs also contain nickel and copper, classified as Strategic Raw Materials by the EU since 2023. Significant efforts have been made to develop efficient recycling processes for waste LIBs, with pyrometallurgical processes playing a key role. These technologies are relatively mature, with high adaptability for different raw materials and involve smelting waste batteries above the melting points of battery components, followed by separating metals through reduction reactions. This method efficiently recovers cobalt, copper, and nickel as a metal alloy or matte, while lithium and manganese are lost in the slag phase. The goal of this work was to enhance the recovery of valuable battery metals by combining hydro- and pyrometallurgical processes. Mechanically prepared battery black mass underwent selective sulfation roasting to convert LiCoO 2 and Mn-oxides into Li, Co, and Mn sulfates. After roasting, the battery scrap was leached in distilled water at 60 °C, recovering 95% of lithium, 61% of manganese, and 35% of cobalt. The solid leaching residue was then mixed with industrial Ni-slag and biochar. Two experimental series were carried out, one with the addition of industrial Ni-concentrate and one without. The smelting experiments were conducted at 1350 °C in flowing argon atmosphere as a function of time (5–60 min) to investigate the reduction behavior of battery metals. The results show that Co and Ni from the slag and leach residue can be efficiently recovered in the slag cleaning stage. Graphical Abstract