Sustainable Mining and Metallurgy

In the disassembly of spent lithium-ion batteries, the remaining aluminum slag after the stripping of the cathode sheet powder contains valuable metals such as Al, Li, and Fe. In this paper, based on the basic principles of molten salt method and vacuum metallurgy, the comparative experiments of conventional aluminum slag recovery process (molten salt method) and vacuum distillation were carried out. The effects of smelting atmosphere, temperature, time and additive dosage on the grade and direct yield of recycled aluminum were studied, and the recovery way of metal Li was discussed. The results show that in the atmospheric pressure recovery method, under the conditions of melting temperature 850℃, melting time 60min and CaF₂ addition amount 3%, the Al grade of regenerated aluminum reaches 98.54% and the direct recovery rate is 68.43%. The metal Li reacts with the flux and enters the brine after washing. In the vacuum distillation method, under the condition of melting temperature of 1050℃ and melting time of 3h, the grade of recycled aluminum Al is 99.55%, and the direct recovery rate is 85.50%. Most of the metal Li volatilizes into the flue gas under vacuum. The advantages of atmospheric pressure recovery process are low energy consumption, low cost and simple equipment，and the disadvantage is that the process is long, the flux needs to be added, the grade of recycled aluminum and the direct recovery rate are low. The advantages of vacuum recovery process are short process, no other flux, high aluminum grade and direct recovery rate，and the disadvantages are high energy consumption, high cost and high equipment requirements.