Direct Lithium Extraction from α-Spodumene through Solid-State Reactions for Sustainable Li<sub>2</sub>CO<sub>3</sub> Production
Shilong Wang, Nathan J. Szymanski, Yuxing Fei, Wenming Dong, John N. Christensen, Yan Zeng, Michael Whittaker, Gerbrand Ceder
Abstract
High Resolution Image Download MS PowerPoint Slide With increasing battery demand comes a need for diversified Li sources beyond brines. Among all Li-bearing minerals, spodumene is most often used for its high Li content and natural abundance. However, the traditional approach to process spodumene is costly and energy-intensive, requiring the mineral be transformed from its natural α to β phase at >1000 °C. Acid leaching is then applied, followed by neutralization to precipitate Li 2 CO 3 . In this work, we report an alternative method to extract Li directly from α-spodumene, which is performed at lower temperatures and avoids the use of acids. It is shown that Li 2 CO 3 is formed with >90% yield at 750 °C by reacting α-spodumene with Na 2 CO 3 and Al 2 O 3 . The addition of Al 2 O 3 is critical to reduce the amount of Li 2 SiO 3 that forms when only Na 2 CO 3 is used, instead providing increased thermodynamic driving force to form NaAlSiO 4 and Li 2 CO 3 as the sole products. We find that this reaction is most effective at 4 h, after which volatility limits the yield. Following its extraction, Li 2 CO 3 can be isolated by washing the sample using deionized water. This energy-saving and acid-free route to obtain Li 2 CO 3 directly from spodumene can help meet the growing demand for Li.