Prioritized recovery of lithium from spent lithium-ion batteries by synergistic roasting with Na2SO4: Precise regulation

Due to its dual attributes of environment and resources, the development of green and low-carbon and the recycling of valuable metals have become a research hotspot in the field of spent lithium-ion batteries recycling. For the black mass, the reductant of Na₂SO₄ was selected to achieve efficient and preferential extraction of lithium by regulating the formation of the reduction products, investigating the mechanism of the synergy between in-situ carbothermal reduction and Na₂SO₄ roasting. The results demonstrated that the leaching efficiency of lithium from Black Mass was 80.93% under the optimal conditions of 20 g Na₂SO₄ dosage, roasting temperature of 700 ℃, and roasting time of 150 min. Comprehensive characterization revealed that the addition of Na₂SO₄ facilitated the transformation of Li from Li₂CO₃ to LiNaSO₄, which has high solubility, and preventing the excessive reduction of Ni/Co oxides to the metallic states. The efficient separation and enrichment of lithium from spent LIBs was achieved by the accurate targeted transformation of the NCM during the synergistic roasting process, promising applications in the spent lithium-ion battery recycling industry.