Integrated Sorbent-based Lithium, Power, and Water Recovery from Geothermal Brines

Geothermal brines used in power generation can be a potential source of critical elements, such as lithium. However, current technological approaches cannot achieve high selectivity of target elements available in trace concentrations from a complex geothermal brine matrix with high concentration of non-desirable mineral content. StratoFire and Southern Research propose to develop and optimize an integrated membrane- and sorbent-based process to extract lithium from geothermal brines while producing clean water, below 500 ppm total dissolved solids, at low energy consumption. The proposed approach consists of silica removal, nano-filtration to selectively extract lithium, membrane distillation to concentrate lithium, and an innovative mineral recovery system. Southern Research has already completed proof of concept lab studies of the process. Phase I study will continue to focus on (1) further improvement and optimization of the lithium sorbent and (2) perform rapid validation studies for using real geothermal brines with nanofiltration and membrane distillation and (3) perform updated technoeconomic analyses for improved systems and scenario analysis of different system integrations for different real world brine characteristics and output needs. U.S. domestic lithium production is extremely limited, despite potential resources and significant and growing demand for lithium based products in the domestic market. U.S. industries (electronics, energy, and defense) that utilize elements such as lithium can be severely impacted were their supply sources not expanded or diversified. DOE funding will enable systematic study of low-cost desalination methods for the recovery of strategic material such as lithium using domestic brine resources at US geothermal power plants as well as oil field production sites, potentially further enabling the scale-up of geothermal power generation by providing beneficial side products. Successful demonstration of water technologies translated to critical element recovery from geothermal fluids may lead to more widespread application of this approach to other industries and wastewaters (such as mining wastewater), further broadening and effectively multiplying the impact.