Sizing up the challenges in extracting lithium from geothermal brine

If you had a jar of marbles of galore antithetic colors but wanted lone the greenish ones, however could you efficiently prime them out? What if it wasn't marbles but a jar of glitter, and determination was sand, glue, and mud mixed in? That begins to picture the complexity of the brine pumped retired from beneath California's Salton Sea arsenic portion of geothermal vigor production.

For geothermal fields astir the world, produced geothermal brine has been simply injected backmost underground, but present it's go wide that the brines produced astatine the Salton Sea geothermal tract incorporate an immense magnitude of lithium, a captious assets request for low-carbon proscription and vigor storage. Demand for lithium is skyrocketing, arsenic it is an indispensable constituent successful lithium-ion batteries. Currently determination is precise small lithium accumulation successful the U.S. and astir lithium is imported; however, that whitethorn alteration successful the adjacent future.

Researchers from the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) person precocious published a broad reappraisal of past and existent technologies for extracting minerals from geothermal brine. The review, published successful the diary Energies, discusses and evaluates a wide array of technologies utilized for extraction of lithium from brines. The reappraisal finds that geothermal brines successful the Salton Sea portion of California are expected to beryllium a large home root of lithium successful the aboriginal but that important method challenges request to beryllium overcome.

"One of the large drivers for processing home lithium resources present is that we volition request a batch of lithium successful the future." said Will Stringfellow, pb writer of the paper. "We are babelike connected lithium that's extracted from the world successful different countries—and it's besides processed overseas—so we don't person immoderate important home artillery production. But determination are perchance a batch of lithium resources successful the United States that could beryllium exploited. So, we're looking astatine whether those resources tin beryllium extracted and utilized successful a truly environmentally affable manner, truthful that they're genuinely 'green' lithium sources."

Extraction of lithium from geothermal brines is expected to beryllium peculiarly challenging. The brine is highly blistery erstwhile it comes retired of the subsurface, and it contains a affluent stew of galore dissolved minerals successful summation to lithium. "It comes retired astatine implicit 100 degrees Celsius," Stringfellow said. "So, you person to woody with the heat. And it's very, precise saline—about 25% by weight. There's a batch of salt, meaning a batch of sodium, a batch of chloride. There's besides a batch of calcium and magnesium, and different things similar robust and silicon. These are each materials that could perchance interfere with the extraction."

The Department of Energy (DOE) is funny successful some geothermal vigor and the lithium proviso chain, said Stringfellow, who is an adept connected concern discarded attraction and management. "We were commissioned by DOE's Geothermal Technologies Office to behaviour an autarkic investigation of mineral extraction exertion successful the discourse of geothermal vigor production," helium said. "There person been erstwhile reviews of idiosyncratic cardinal processes, but this is, to our knowledge, the archetypal broad reappraisal that looked astatine the much applied-science broadside of the process."

Stringfellow and co-author Patrick Dobson, pb of Berkeley Lab's geothermal systems program, looked astatine the published lit and concern and authorities reports, and conducted a thorough reappraisal of lithium extraction exertion patents. The astir technologically precocious method of lithium extraction is adsorption of lithium utilizing inorganic sorbents, but different promising technologies are besides being developed. Inorganic molecular sieve ion-exchange sorbents are being applied for extraction of lithium from brines, and the past and existent exertion of this exertion are discussed successful the paper.

Dobson and Stringfellow are members of the Lithium Resource Research and Innovation Center (LiRRIC), established astatine Berkeley Lab to make subject and exertion for sustainable home lithium extraction, refining, and materials synthesis for applications specified arsenic batteries.

Recent projects person focused connected however to find the chemic creation of blistery brine successful real-time, without needing to chill it down, enabling amended process power to maximize the ratio of lithium extraction. They besides are moving connected technoeconomic analysis with 2 companies operating astatine the Salton Sea—Berkshire Hathaway Energy and Controlled Thermal Resources—to spot if lithium extraction technologies tin beryllium done successful a mode that makes it cost-competitive with different forms of lithium production. These efforts are supported by the California Energy Commission and DOE's Advanced Manufacturing Office.

"Berkeley Lab pioneered lithium artillery technologies and is continuing to propulsion the forefront of lithium artillery innovation by utilizing earthy resources and interacting equitably with the communities successful which these resources reside," said Mike Whittaker, manager of LiRRIC.

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More information: William T. Stringfellow et al, Technology for the Recovery of Lithium from Geothermal Brines, Energies (2021). DOI: 10.3390/en14206805