Technology for the Recovery of Lithium from Geothermal Brines

Abstract

Lithium is the principal component of high-energy-density batteries and is a critical material necessary for the economy and security of the United States. Brines from geothermal power production have been identified as a potential domestic source of lithium; however, lithium-rich geothermal brines are characterized by complex chemistry, high salinity, and high temperatures, which pose unique challenges for economic lithium extraction. The purpose of this paper is to examine and analyze direct lithium extraction technology in the context of developing sustainable lithium production from geothermal brines. In this paper, we are focused on the challenges of applying direct lithium extraction technology to geothermal brines; however, applications to other brines (such as coproduced brines from oil wells) are considered. The most technologically advanced approach for direct lithium extraction from geothermal brines is adsorption of lithium using inorganic sorbents. Other separation processes include extraction using solvents, sorption on organic resin and polymer materials, chemical precipitation, and membrane-dependent processes. The Salton Sea geothermal field in California has been identified as the most significant lithium brine resource in the US and past and present efforts to extract lithium and other minerals from Salton Sea brines were evaluated. Extraction of lithium with inorganic molecular sieve ion-exchange sorbents appears to offer the most immediate pathway for the development of economic lithium extraction and recovery from Salton Sea brines. Other promising technologies are still in early development, but may one day offer a second generation of methods for direct, selective lithium extraction. Initial studies have demonstrated that lithium extraction and recovery from geothermal brines are technically feasible, but challenges still remain in developing an economically and environmentally sustainable process at scale.

Cation–Ligand Interactions Dictate Salt Partitioning and Diffusivity in Ligand-Functionalized Polymer Membranes

“…Lithium salts are in high demand due to their use in batteries and electric vehicles. However, current lithium production methods are volatile and require a laborious solar evaporation process which may not scale to meet projected demand …”

“…However, current lithium production methods are volatile and require a laborious solar evaporation process which may not scale to meet projected demand. 1 Membranes are an attractive alternative to current thermally based separations due to their proven scalability and energy efficiency in desalination applications. 2 Unfortunately, many membrane materials available today cannot easily differentiate between ionic solutes, especially alkali cations, precluding their use in brine separation.…”

Recent Advances in the Lithium Recovery from Water Resources: From Passive to Electrochemical Methods

“…[113,114] A comprehensive overview of the patents and methods to recover lithium from geothermal waters with AlOH sorbents can be found in Stringfellow and Dobson. [115] In other cases, aluminum-based powders were not used as sorbents but as a mean to make lithium precipitate as lithium aluminate reaching a precipitation rate of 78.3%. [116] A similar idea was investigated by Xiang and co-workers first to remove Mg from brines with a high Mg:Li ratio and then to recover lithium directly from the brine through the nucleation and successive crystallization of LDHs.…”

“…[ 113,114 ] A comprehensive overview of the patents and methods to recover lithium from geothermal waters with AlOH sorbents can be found in Stringfellow and Dobson. [ 115 ]…”

Ionic Liquids for the Selective Solvent Extraction of Lithium from Aqueous Solutions: A Theoretical Selection Using COSMO-RS

“…Brine is the principal source of lithium [5], but its extraction and separation are tedious because these processes require a solar evaporation step to concentrate the mineral, which results in long processing times ranging from six to eighteen months. Subsequently, magnesium, calcium, and boron are removed in several stages of precipitation using sodium carbonate and lime [6]. In addition to this, large quantities of freshwater have to be injected into the lithium wells to pump off the brines, which causes water pollution, affecting the biodiversity of the environment and human health [7], not to mention the fact that water is extremely scarce in places where lithium is found [8].…”