Batch-scale Synthesis of a new Inorganic Sorbent for Extracting Lithium from Brine

Abstract

Giga factories are being built around the world to meet the growing demand for lithium batteries – but despite increasing demand, the domestic supply of lithium (Li) remains relatively constrained. The limited sources of Li now make this metal strategically important. Natural sources of Li include spodemene minerals and salt-lake brines. Both of these processes for securing Li are costly and time-consuming. A new method is now being developed to extract Li from salt-lake brines, using well-crafted sorbents. A Li sorbent is a material that extracts Li ions selectively from an aqueous solution, while leaving other ions, such as sodium, calcium and potassium, in solution. When absorption sites on the sorbent are loaded with Li, the Li can be desorbed by rinsing the sorbent with Deionized-H2O. Our project focused on synthesizing Lithium-Aluminum Layered Double Hydroxide Chloride, xLiCl*2Al(OH)3*mH2O (Li/Al LDH). Li/Al LDH is highly selective for Li, and should be readily scalable to industry needs. We also synthesized and tested 3 manganese-based sorbents. For large-scale synthesis of Li/Al LDH, we determined concentration, time, and quantity needed in a 750-ml capacity batch reactor. We successfully synthesized ~ 200 g of Li/Al LDH in a single batch. X-ray diffraction data revealed the presence of a single LDH phase. We are currently testing Li sorption from bine solutions through Li concentration measurements made by inductively coupled plasma optical emission spectrometry. By scaling the Li/Al LDH sorbent process to pilot-scale production, American industries can now better meet the rapidly increasing demand for Li.