UC Berkeley

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 Li₂CO₃. 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 Li₂CO₃ is formed with >90% yield at 750 °C by reacting α-spodumene with Na₂CO₃ and Al₂O₃. The addition of Al₂O₃ is critical to reduce the amount of Li₂SiO₃ that forms when only Na₂CO₃ is used, instead providing increased thermodynamic driving force to form NaAlSiO₄ and Li₂CO₃ as the sole products. We find that this reaction is most effective at 4 h, after which volatility limits the yield. Following its extraction, Li₂CO₃ can be isolated by washing the sample using deionized water. This energy-saving and acid-free route to obtain Li₂CO₃ directly from spodumene can help meet the growing demand for Li.