Selective separation of lithium from the hydrochloric acid leachate of lithium ores via the extraction system containing TBP-FeCl3

Abstract

The elevation of comprehensive lithium recovery remains a formidable challenge in lithium extraction from lithium bearing ores due to the equilibrium solubility constraints affecting the lithium precipitation reaction. Hence, this work drew inspirations from lithium extraction techniques in salt lakes by characterizing the hydrochloric acid leachate of lithium ores as a distinct brine. The leachate composition was regulated and solvent extraction technology for selective lithium extraction was developed. By employing the loaded organic phase with Fe3+ (2TBP-NaFeCl4) to extract the leachate, and utilizing a four-stage countercurrent extraction process, the extraction efficiency of lithium could be achieved at 99 % at least. Following three-stage scrubbing and two-stage countercurrent stripping experiments, the stabilized stripping efficiency of lithium was 99.24 %. The concentration of Li+ in the stripping solution was enriched up to 16.404 g/L, while the total concentration of impurity ions was only 0.424 g/L. The resulting lithium-enriched solution could be utilized to prepare high-purity lithium chloride. This process has achieved a highly selective and efficient extraction of lithium, thereby enhancing the overall lithium extraction efficiency. The Density Functional Theory results indicate that the loaded organic phase selectively extracted lithium through ion exchange.