Pilot Scale Recovery of Lithium from Geothermal Brines

Expansion of geothermal energy production in California will greatly benefit from the creation of a value stream generated from the recovery of useful metals, such as lithium, from geothermal fluids.

The efficient direct extraction of lithium from geothermal brines promises to make geothermal power generation economically favorable and secure lithium production in the United States to support a carbon-free economy.

The purpose of this project was the pilot scale demonstration of lithium extraction from geothermal brines. The direct lithium extraction process was validated on the pilot scale skid with synthetic brine resulting in direct production of lithium carbonate. Extraction of lithium from geothermal brine provides several advantages. At a high temperature, lithium-rich fluid is pumped to the surface, heat is removed from the brine and used to drive a turbine to produce electricity, and lithium is extracted from the brine before the spent brine is reinjected underground. The estimated cost of direct lithium extraction is on par with that of hard rock-based lithium production processes. The direct lithium extraction process permits the rapid processing of brines and extraction of lithium with high recovery efficiency taking hours instead of months and is environmentally friendly compared to conventional production processes.

Further research is needed to increase the sorbent lifetime as sorbent replacement represents a significant part of the operating cost. To ensure suitability of materials of construction and components, the skid should be operated in field at a geothermal site for an extended duration.