Reaction behavior of CO2 gas in a new three-phase gas-liquid-liquid stripping process for lithium recovery

Solvent extraction is an important method for extracting lithium from salt lake brines. CO2 stripping for lithium recovery is a novel extraction technique for lithium extraction from salt lakes, which also has the advantage of being able to directly prepare lithium carbonate instead of using strong acid and sodium carbonate. This study investigates the chemical behavior of CO2 in the lithium stripping process and its impact on carbonate systems by combining experimental data with thermodynamic calculations. During the CO2 stripping process, lithium initially converts into lithium carbonate, and with the continuous introduction of CO2, lithium carbonate gradually transforms into lithium bicarbonate. At equilibrium, the proportions of lithium carbonate and lithium bicarbonate are 11.8% and 88.2%, respectively (in terms of Li content). This study provides a theoretical foundation for optimizing lithium extraction processes and improving lithium resource utilization.