Recovery of Lithium from Beta-Spodumene Through Serial Calcination and Water Leaching with CaO

Lithium recovery from β-spodumene was conducted using a hydrometallurgical process consisting of water leaching and calcination. Water leaching experiments were conducted using a mixture of β-spodumene and CaO. The effect of experimental parameters such as the particle size of β-spodumene, reaction temperature, reaction time, and mass ratio of CaO to β-spodumene on the lithium leaching efficiency was investigated. The Ca(OH)2 and CaCO3 in the leach residue were converted to CaO by calcination at 900°C. The calcined product was recycled into in the leaching process to recover additional lithium. Four leaching stages based on a 75-μm particle undersize, reaction temperature of 100°C, 3:1 mass ratio of CaO to β-spodumene, and overall reaction time of 9 h resulted in 97% lithium yield from spodumene. The process developed in this work succeeded in reducing the overall amount of chemicals used relative to the conventional spodumene treatment process, allowing for the effective leaching of lithium through a simple hydrometallurgical process. In addition, given that the final leach residue consisted of Ca(OH)2 and CaCO3, it could be reused in the water leaching process following calcination, further contributing to the sustainability of the proposed process