Much of the planet’s lithium is contained in brine, but the concentration is often quite low, making it difficult to efficiently extract lithium — typical extraction technologies may only demonstrate 30–60% yield. Adionics (Les Ulis, France; www.adionics.com) has developed a proprietary liquid-extraction medium called Flionex to be used in a patented thermal-swing liquid-liquid deionization process to enable extremely high recovery and selectivity for lithium. When raw brine is brought into contact with Flionex, all lithium is extracted, little sodium and little calcium are co-extracted, while other elements, such as potassium, boron, magnesium and sulfates, are rejected. The loaded medium is then washed with cool water to remove the undesired sodium and calcium, which are partially desorbed, while lithium remains in the organic phase. Finally, the loaded Flionex is contacted with heated demineralized water. Only the lithium and chloride are released into the aqueous phase, forming a concentrated stream of LiCl. The newly regenerated Flionex is sent back to the extraction phase.
“It is important to highlight that Adionics’ process does not require any chemical input throughout the process besides a limited amount of freshwater. This technology guarantees lithium recovery up to 99% with purity up to 99%,” says François-Michel Colomar, an engineer and Adionics’ head of external relations. Furthermore, he notes, the extraction technology can be adapted to recover lithium from different brine sources, including geothermal sites, industrial effluents and battery-recycling facilities. Notably, the selectivity makes the process suitable for magnesium- and sulfate-rich brines, which cannot be processed using typical lithium-extraction methods. The depleted brine can be reinjected to the Salar without any pre-treatment, since the technology does not change brine pH, says Colomar.
The company recently completed extensive testing of the technology (over 1,500 h) at a pilot plant in Chile’s Salar de Atacama, producing 99% pure LiCl. The tests showed stable operation with a wide range of brine concentrations at fluctuating temperatures. The company has also built a 250-ton/yr demonstration plant, which is to be installed in Argentina, and initial engineering work is underway for a 20,000-ton/yr commercial-scale plant.