Simbol Materials, a Californian company, plans to extract lithium, as well as zinc and manganese, from the brine that is pumped by geothermal power plants.

Currently many geothermal plants pump hot brine from deep underground to produce steam and then inject the cooled brine back into the ground. This brine is rich in minerals including lithium, which is abundant in the Earth’s crust but does not often occur in concentrations which can be economically exploited.

In 2010, worldwide demand for lithium chemicals was about 102,000 tonnes. This is expected to increase to as much as 320,000 tonnes by 2020 – mostly because of increased electric vehicle use.

Simbol plans to piggyback on a 50 megawatt geothermal plant near the Salton Sea in Imperial Valley, California, that pumps hot brine from deep underground to generate steam. Currently, the brine, which contains 30% dissolved solids, including lithium, manganese and zinc, is pumped back into the ground.. Simbol will divert the brine from the power plant into its processing equipment where the salts will be filtered out.

Simbol plans to begin construction of a commercial plant in 2012. It is expected to have the capacity to produce 16,000 tonnes of lithium carbonate a year at a price competitive with the current lowest-cost producers.