Extraction of metals from spent lithium ion batteries- Role of acid, reductant and process intensification in recycling

A comparison of various approaches evaluated to process spent lithium ion batteries to extract metals has been carried out. The leaching is carried out with sulphuric acid in the presence and absence of reductant, thus defining the role of reducing agent (NaHSO3 and H-2 O-2) in assisting dissolution of all metals, especially Co and Mn. As the direct process incurs all metals in solution and employs high concentration of acid, a two-step process (acid baking and leaching) has been attempted to lower acid consumption indicating benefits in the selective dissolution of metals viz., Co and Li (in 1(st) stage) over other metals (Ni and Mn in 2(n)(d) stage).