Utilizing captured CO2 to concentrate lithium from dilute brines

CMI researchers from Idaho National Laboratory conducted the activity for this highlight

Innovation 
The most common industrial carbon capture technology relies on absorption of CO₂ from flue gas by an aqueous amine. The CO₂ is typically subsequently released by heating the solution, and then the CO₂ must be compressed and transported for storage. These steps have high energy costs. Instead, we use the CO₂-loaded amine to react with dilute lithium brines, which converts the carbon into insoluble metal carbonates (e.g., CaCO₃, MgCO₃). Electrodialysis is then used to regenerate the amine and produces a more concentrated Li solution.

Achievement

• Recycled >75% of the reagent used for CO₂ capture. 
• Demonstrated >4-fold Li concentration with a surrogate solution (140 mg/L to 580 mg/L).

Significance and Impact

• Utilizing and mineralizing captured CO₂, at lower energy cost than conventional carbon sequestration. 
• Reducing chemical usage and environmental impact through regeneration of reagent.

Hub Target Addressed 
Efficient use of energy and water.