Sustainable Mining and Metallurgy

With the rapid development of the new energy industry, lithium hydroxide, as a key raw material for lithium-ion batteries, has seen a continuous growth in market demand. Therefore, optimizing the production process of lithium hydroxide has become a current research hotspot. The process of preparing lithium hydroxide via the lithium carbonate-lime causticization features simplicity and high efficiency, and it can convert low-grade lithium carbonate into high-value-added lithium products. However, during the causticization reaction, calcium carbonate slag with 0.5%~1.2% lithium is generated, leading to the loss of lithium resources. To improve the lithium recovery rate, it is necessary to wash the calcium carbonate slag with water to reduce its lithium content. Based on the lithium carbonate-lime causticization process, this study explored the purification effect of multi-stage water washing on calcium carbonate slag through experiments. The results show that after two-stage washing, the main component content of the obtained calcium carbonate slag reaches 98.21%, and the residual lithium content is reduced to 0.09%, which significantly improves the lithium recovery efficiency.