Efficient lithium extraction by low-temperature roasting and leaching residue recycling: Comprehensive utilization of clay-type lithium ore

Abstract

The growing demand for lithium from electric vehicles and electrochemical energy storage has highlighted clay-type lithium ore as a promising supplementary resource. However, its development is constrained by the high temperature requirements of extraction processes and the insufficient utilization of aluminosilicate-rich leaching residues. A NaHSO₄-based strategy integrating low-temperature roasting with room-temperature water leaching was proposed for lithium recovery and residue valorization. The lithium leaching rate reached 91.04% under the optimal conditions. The mechanism study showed that the molten NaHSO₄ provided an acidic environment during the roasting process, and the decomposition of pyrosulfate induced the deconstruction of aluminosilicate ore through a liquid-solid reaction, which promoted the migration and release of lithium, inhibited the dissolution of silicon, and selectively dissolved part of aluminum into the leaching solution, realizing the change of the Si/Al ratio of leaching residue. Owing to its suitable Si/Al ratio, the leaching residue was directly converted into X-type zeolite without additional silicon or aluminum sources. The synthesized X-type zeolite exhibited excellent Cu²⁺ adsorption performance (120 mg/g). It was shown that lithium extraction can be coupled with the further utilization of aluminosilicate-rich residues, providing an integrated approach for the utilization of clay-type lithium ore.