Sustainable lithium recovery from hot springs: A multidisciplinary approach

As technology and development advance, global demand for lithium is expected to grow exponentially yearly, hence the need to explore new natural resources to supply the rapid demand. As a leading water resource, lithium is extracted from brines, including salt lakes, geothermal, and oilfield brines. Addressing the lack of studies on new exploitable water resources for lithium extraction, this review presents hot springs as a novel secondary resource for lithium extraction by exploring geological and engineering aspects. The geological section provides information on the genesis of hot springs, mineral structures containing lithium, and the main mechanisms of lithium enrichment in water resources related to water-rock interactions. On the other hand, traditional (i.e., evaporation and chemical precipitation) and advanced lithium extraction engineering techniques, such as direct lithium extraction techniques (i.e., ion exchange, adsorption, solvent extraction, and membrane-based techniques), are here proposed and investigated for hot springs. The review outlines the mechanisms, parameters, and efficiencies associated with the various extraction techniques, highlighting their negative environmental impact and sustainability aspects. Finally, critical aspects and future perspectives are discussed here.