In-Situ Co-Precipitation and separation concentration of Al3+/Li+ in leachate from Low-Grade lithium ore

In situ synthesis of Li 5 AlO 4 through CO 2 controlled co-precipitation. • The hydrothermal method breaks the Li 5 AlO 4 lattice bonds, separation of Al 3+ /Li + . • A novel route for Li extraction from low-grade lithium ores. With lithium becoming increasingly essential for the production of batteries, the extraction of lithium from low-grade ores has drawn considerable attention. After roasting and acid leaching of low-grade lithium ore, the content of lithium element in the leachate is relatively low, while the content of impurities (Al, Fe, Ca, etc) is relatively high, which complicates the separation and the preparation of high-purity lithium salts. Herein, the leachate derived from low-grade clay-type lithium ore is employed as the raw material. Initially, chemical precipitation is applied to sequentially remove Fe 3+ , Ca 2+ , and Mg 2+ through pH adjustment. Subsequently, CO 2 is introduced into a solution containing Al 3+ and Li + to control the pH, thereby regulating the precipitation kinetics of Al 3+ . This enables the co-precipitation of Al 3+ /Li + and in-situ generates pentalithium aluminate (Li 5 AlO 4 ) compounds. Finally, a hydrothermal method is employed to successfully cleave the Li–O/Al–O bonds within the Li 5 AlO 4 lattice, achieving separation of Al 3+ and Li + ions. This process facilitates Li + enrichment and the successful preparation of high-purity Li 3 PO 4 . Meanwhile, the aluminum oxyhydroxide (AlO(OH)) as a byproduct was obtained. Products and intermediate stages characterization and analysis were performed using various analytical methods. Theoretical analysis was conducted on the Al-Li co-precipitation and the subsequent Li + leaching mechanism. This innovative method offers a novel approach for the efficient extraction of lithium resources from low-grade lithium ores. Download: Download high-res image (134KB) Download: Download full-size image