Princeton scientists have developed a method that cuts down the land and time necessary for lithium production and can optimize existing facilities.
Essential in batteries for electric vehicles and energy storage, lithium is vital for a green energy future. Yet, its production carries significant environmental costs, including the vast land and time needed to extract it from saline waters, with substantial operations spanning large areas and often taking over a year to start production.
Scientists at Princeton have created a method that significantly reduces the land and time required for lithium production. According to the researchers, their approach can enhance operations at current lithium plants and tap into reserves that were earlier deemed too minor or diluted to be valuable.
When submerged in a salt-water solution, the ends of the strings facilitate water movement upwards through capillary action, a mechanism similar to how trees transport water from roots to leaves. The water swiftly evaporates from the surface of each string, depositing salt ions, including sodium and lithium. As the evaporation persists, the salts become more concentrated, eventually forming sodium chloride and lithium chloride crystals on the strings for convenient extraction. Moreover, this method naturally segregates lithium and sodium at separate locations on the string, attributed to their distinct physical properties; the less soluble sodium crystallizes at the lower segment, whereas the highly soluble lithium salts solidify near the top. This natural partitioning enables the researchers to isolate lithium and sodium individually, bypassing the typical necessity for additional chemicals.
An evaporation pond on a string
The string technique is considerably more compact and expedites lithium production. Despite the acknowledgement from researchers that scaling the technology from a laboratory setting to an industrial level necessitates further efforts, they anticipate a potential reduction in land usage by over 90% compared to existing methods and a more than 20-fold increase in the evaporation process speed, potentially facilitating initial lithium yields in less than a month. This efficient and economical approach could broaden lithium access to new sources, including abandoned oil and gas wells and geothermal brines, which are currently deemed too minor or too diluted for lithium extraction. The rapid evaporation rate enables operations in humid environments, with ongoing investigations exploring the feasibility of utilizing this technology for lithium extraction from seawater.
Using affordable materials and previous chemical treatments, the researchers believe their improved method is poised for widespread adoption, demonstrating its scalability with a 100-string lithium extraction array.
Reference: Chen, X, et al, Spatially separated crystallization for selective lithium extraction from saline water, Nature Water (2023). DOI: 10.1038/s44221-023-00131-3. www.nature.com/articles/s44221-023-00131-3
