Cleaner and effective recovery of metals and synthetic lithium-ion batteries from extracted vanadium residue through selective leaching

A process for recycling steelmaking waste is proposed, and high value-added lithium-ion batteries (LIBs) electrode materials LiFePO4 and Li4Ti5O12 are prepared. The precursor material FePO4·xH2O is prepared from the iron-rich filtrate formed after HCl leaching the waste residue. Using FePO4·xH2O and Li2CO3 as raw materials by the carbothermal reduction method, LiFePO4 containing a small amount of metal doping is prepared. By comparing the XRD patterns, it is found that the purity of the synthesized LiFePO4 material is higher if the precursor whose Fe–P molar ratio is close to the theoretical value of 1 is used as the raw material. The initial discharge capacity of LiFePO4/C at 0.1C is 139.3 mAh·g−1, and after 50 cycles, the capacity retention rate is 94.97%. In sulfuric acid medium, NH3·H2O and H2O2 are used to selectively leaching Ti from the titanium-rich slag. High-purity TiO2 is prepared by calcining the peroxy titanium compound. The spinel-type lithium-ion battery anode material Li4Ti5O12 is prepared with TiO2 as the precursor. The initial discharge capacity of the battery assembled with Li4Ti5O12 at 0.1C is 163.3 mAh·g−1. This study is helpful to solve the environmental pollution problem and the energy crisis.