Novel approach for metal separation from spent lithium ion batteries based on dry-phase conversion

Wet leaching has been commonly applied to separate metals out from spent lithium ion batteries (LIBs), and large volumes of chemicals including acids and additives are required to reach high metal separation efficiencies. To reduce heavy use of chemicals for metal separation becomes significant in cleaner production. We propose a dry-phase process as chlorination conversion for separating metals from spent LIBs with low-stoichiometric amounts of additive. With ammonium chloride (NH4Cl) as the only additive, high metal separating efficiencies are achieved. Based on theoretical analysis and experimental investigation, it was found that chlorination conversion was promoted in a relatively closed environment and the suitable reaction temperature was between 623 K and 800 K. By parameter optimization, nearly 100% extracting efficiencies of Li and Co were achieved at 673 K for 20 min with the mass ratio of w(LiCoO2)/w(NH4Cl) as 1:2 under air atmosphere. Furthermore, the reaction mechanism was described as a two-step process which could be illustrated as the dry-extraction of LiCoO2. Finally, an acid-free approach was developed to realize the efficient metal extraction from cathode materials of spent LIBs. [Display omitted] •An acid-free process for metal separation from spent lithium ion battery is proposed.•High metal separating efficiency is obtained with NH4Cl as the only additive.•A dry-extraction mechanism is proposed to explain the metal separation.