Demand for lithium has accelerated quickly, but the methods used to obtain it remain slow and limited to specific environments. Researchers from Columbia Engineering say a new chemical extraction technique may offer an alternative.
In a study published in Joule, the team outlines a process known as switchable solvent selective extraction (S3E). The solvent-based method is designed to recover lithium directly from brines, potentially reducing extraction times while making previously uneconomic resources more viable.
If the process proves scalable, it could broaden the range of lithium sources available to producers and reduce reliance on large evaporation operations currently used in major lithium-producing regions.
Around 40% of global lithium supply currently comes from underground brine deposits. In locations such as Chile’s Atacama Desert, producers pump mineral-rich brine into expansive evaporation ponds where water slowly evaporates over months or even years, leaving concentrated lithium salts behind.
The approach works best in dry climates with strong solar radiation and large tracts of land. Even in ideal conditions, however, the process can take up to two years to complete.
The method also has operational constraints. Evaporation systems require substantial land areas and can place pressure on local water supplies—an increasingly sensitive issue in regions already facing freshwater scarcity.
Another limitation is the chemistry of the brines themselves. Many promising lithium resources contain relatively low lithium concentrations alongside high levels of competing minerals. In these environments—such as geothermal reservoirs or oilfield wastewater streams—traditional evaporation methods often struggle to produce lithium efficiently.
Researchers are exploring direct lithium extraction (DLE) techniques to address these challenges. The S3E system represents one example of that broader push.
The S3E process relies on an amine-based solvent designed to alter its chemical behavior depending on temperature.
At lower temperatures, the solvent becomes hydrophilic, allowing it to interact with water and capture lithium ions from brine solutions. When heated, the solvent shifts to a hydrophobic state, releasing the lithium into a purified liquid stream while regenerating the solvent for reuse.
Laboratory experiments suggest the system can differentiate lithium from other common ions found in brines:
Researchers also found the solvent maintained its performance across multiple extraction cycles, an important factor for potential industrial deployment.
Initial tests used synthetic brines designed to replicate the chemistry of fluids found in California’s Salton Sea geothermal region, an area believed to hold enough lithium to support hundreds of millions of electric vehicle batteries.
After four extraction cycles using the same batch of solvent, the system recovered about 40% of the lithium in the modeled brine.
While the work remains at an early stage, the researchers suggest the process could eventually support continuous extraction systems powered by relatively low-temperature heat sources, including solar thermal energy or industrial waste heat.
If developed commercially, solvent-based extraction methods like S3E could broaden the types of lithium resources considered economically viable. Potential feedstocks could include:
Beyond supply expansion, the approach could also reshape the environmental footprint of lithium production. By avoiding large evaporation ponds and reducing water demand, solvent-based direct extraction systems may offer a lower-impact alternative to some existing production methods.
