Synergistic roasting of spent lithium-ion batteries and nickel matte for preferential lithium extraction and efficient leaching of transition metals

The rapid advancement of new energy vehicles , coupled with their limited service life, has led to a significant increase in spent lithium-ion batteries (LIBs). Recognized for both their environmental and resource potential, these spent batteries represent an urban mineral resource whose recycling has emerged as a critical research focus. Notably, as an intermediate product in the nickel ore production process, nickel matte exhibits a significant resemblance to spent LIBs in terms of elemental composition . Consequently, this study innovatively proposes to utilize nickel matte as a sulfating agent and reductant for the synergistic roasting with spent LIBs and establishes a “S-O” atmospheric system to facilitate the targeted transformation of valuable metals. The lithium present in the cathode materials is selectively transformed into water-soluble Li 2 SO 4 through the regulation of the amount of air, roasting temperature, the dosage of nickel matte and the roasting time , enabling the preferential extraction of lithium via water leaching. Meanwhile, transition metals from the cathode materials and nickel from the matte are converted into lower-valent oxides , which are subsequently extracted by atmospheric acid leaching. Under the optimum roasting and leaching conditions, 96.03 wt% of Li, 99.10 wt% of Ni, 96.74 wt% of Co, and 90.23 wt% of Mn can be extracted. This strategy not only enhances the recovery of strategic metals from spent LIBs but also addresses the limitations inherent in the high-pressure leaching step of traditional nickel matte processing, providing a methodogical reference for the integrated treatment of urban minerals and primary ores.