A new process to produce battery grade lithium carbonate from salt lake brines by purification, synergistic solvent extraction and carbon dioxide stripping

There are abundant lithium resources in China, and the demand for lithium salts is high. However, lithium resources of the sulfate salt lakes in Tibet, such as Baqiancuo Salt Lake, have not been effectively utilised. This study proposes a synergistic extraction system composed of LIX 54, TRPO, and surfactant ADD-1 for efficient lithium extraction from the brine and separation of impurities. The CO2 gas stripped lithium and produced high-purity lithium bicarbonate solution. Thermal decomposition produced lithium carbonate solid from the loaded strip solution. The comprehensive yield of lithium was higher than 95%, and the quality of the lithium carbonate product reached the battery chemical grade standard. This new process offers a new way for the utilisation of lithium resources in salt lakes.