Novel Technology for Synergistic Extraction of Li and Rb from a Complex Lithium Concentrate

Abstract

Li, known as a crucial new energy metal, has received explosive attention. Spodumene and lepidolite are abundant in Li and are usually associated with Rb, and their strategic position becomes increasingly visible. Herein, a novel and economical technology, combining thermal activation with alkali leaching, was proposed to synergistically extract Li and Rb from a complex lithium concentrate composed of spodumene and lepidolite. First, the comparative cooling experiment showed that the chemical reactivity of the water quenching slag was higher than that of the furnace cooling slag. Furthermore, the phase conversion of main minerals during thermal activation was explored. In addition, inert α-spodumene was converted to active β-spodumene after activation. Subsequently, the leaching behavior of each component in the water quenching slag was investigated. In addition, the results demonstrated that 93.0% of Li, 88.1% of Rb, 41.3% of Si, and 2.8% of Al were extracted at the optimal conditions. Ultimately, the adsorption studies confirmed that the leach residue was a feasible material for removal of heavy metal ions. In contrast to the existing extraction technologies, the technology proposed in this study had a significant advantage of low alkali consumption. Additionally, the utilization of leach residue could reduce the generation of solid wastes as well as improve the ecological and economic value of the proposed process.