Highly efficient lithium leaching from α-spodumene via binary composite salts low-temperature roasting process

• Published in: Powder technology 2025-01, Vol.449, p.120404, Article 120404
• Main Authors: Ni, Chenquan, Liu, Chang, Wang, Jieyi, Song, Yinbo, Liang, Yuting, Xie, Weiqi, Zhong, Hui, He, Zhiguo
• Format: Article
• Language: English
• Subjects: Binary composite salts roasting; Lithium; Lithium leaching; Spodumene; Water leaching
• ISSN: 0032-5910
• DOI: 10.1016/j.powtec.2024.120404

With the rapid development and widespread application of lithium-ion batteries, the demand for lithium has surged dramatically, drawing increasing attention to its extraction from spodumene deposits. However, the sustainable development of the lithium industry faces challenges, as traditional processes are hindered by high conversion temperatures, excessive acid consumption, and difficulties in purifying the leachate. Hence, we propose a binary composite additive system based on sodium sulfate‑calcium oxide (Na2SO4-CaO) for roasting α-spodumene at comparative low temperatures. The optimal roasting conditions entailed a mass ratio of spodumene/CaO/Na2SO4 at 1:0.1:0.8, a roasting temperature of 900 °C, a holding time of 2 h, a liquid-to-solid ratio of 5 mL/g, and leaching at 60 °C for 30 min, resulting in an impressive lithium leaching efficiency of 95.45 %. Thermodynamic and kinetic analyses reveal that the roasting formed the product of water-soluble LiNaSO4, which was then dissolved into water, with the leaching process being governed by internal diffusion. [Display omitted] •A composite salt strategy was proposed to extract lithium from α-spodumene.•The lithium leaching rate at the optimal dosage can reach 95.45 %.•The phase transition temperature of α-spodumene decreases to 900 °C.•The roasting-leaching mechanism was elucidated through thermodynamics and kinetics.