Selective Recovery of Lithium from Geothermal Brines

SRI International demonstrated a new process for the extraction of lithium from geothermal brines based on new high-capacity selective sorbents (material used to absorb or adsorb liquids or gases) and a new sorbent regeneration process. Recovery of lithium from geothermal brines is expected to help the economics of geothermal energy production in California by generating revenue from the production and sale of lithium carbonate. Lithium recovery is also expected to create thousands of new jobs in the United States.
Lithium is a high-value metal used in lithium-rechargeable batteries. It is found in low but significant concentrations in geothermal waters (specifically a few hundred parts per million). Because of the very large volume of brine processed in a geothermal power plant (hundreds of cubic meters per hour), even low-lithium brines represent a valuable resource. SRI International’s technology enables lithium carbonate producers to extract lithium from brines using a fast, cost-effective, and selective process adaptable to a variety of brines, including geothermal brines. Compared to traditional methods of lithium recovery from brines, SRI International’s sorbents and regeneration processes are expected to lower the cost of lithium production by allowing online separation with higher recovery efficiency and using smaller volumes of sorbent, minimizing processing time. The project team demonstrated extraction of lithium with efficiency as high as 90 percent and detected no significant loss in capacity after repeated lithium adsorption-desorption cycles.
The co-production of geothermal power and lithium carbonate will effectively lower the cost of geothermal power in California, making geothermal energy competitive with other sources of renewable energy.