Assessing the challenges of extracting lithium from geothermal brine

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Geothermal power plants in the Salton Sea like this one, the John Featherstone plane, produce superheated brine, which is full of lithium and other minerals. Berkeley Lab advances science and technology to make it a “green” source of lithium for the manufacture of household batteries. (Credit: Patrick Dobson / Berkeley Laboratory)

If you had a pot of marbles many different colors but only wanted the green ones, how could you select them effectively? What if it wasn’t marbles but a jar of glitter, and there was sand, glue, and mud mixed in? This begins to describe the complexity of the brine pumped under the Salton Sea in California for geothermal power generation.

For geothermal fields around the world, the geothermal brine produced was simply re-injected underground, but it is now clear that the brines produced in the Salton Sea geothermal field contain an immense amount of lithium, an essential resource for transportation and l low carbon energy. storage room. The demand for lithium is skyrocketing as it is an essential ingredient in lithium-ion batteries. Currently, there is very little lithium production in the United States and most lithium is imported; However, that could change in the near future.

Researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) recently published a comprehensive review of past and current technologies for extracting minerals from geothermal brine. The review, published in the journal Energies, discusses and evaluates a wide range of technologies used for the extraction of lithium from brines. The review reveals that geothermal brines in California’s Salton Sea region are expected to be a major national source of lithium in the future, but significant technical challenges must be overcome.

“One of the main drivers of the development of domestic lithium resources is that we will need a lot of lithium in the future. Said Will Stringfellow, lead author of the article. “We depend on lithium which is mined from the earth in other countries – and it is also processed abroad – so we do not have significant domestic production of batteries. But there is potentially a lot of lithium resources in the United States that could be mined. So we’re looking to see if these resources can be extracted and used in a truly environmentally friendly way, so that they are truly “green” lithium sources.

Extracting lithium from geothermal brines is expected to be particularly difficult. The brine is extremely hot when it comes out of the basement and contains a rich stew of many dissolved minerals in addition to lithium. “It comes out over 100 degrees Celsius,” Stringfellow said. “So you have to deal with the heat. And it’s very, very salty – about 25% by weight. There is a lot of salt, which means a lot of sodium, a lot of chloride. There is also a lot of calcium and magnesium, and other things like iron and silicon. These are all materials that could potentially interfere with mining.

illustration of lithium extraction process

The hot brine that rises from the subsoil as part of geothermal power generation at the Salton Sea in California is a rich stew of minerals, including iron, magnesium, calcium, sodium, and lithium. Using various extraction techniques, lithium chloride can be extracted from brine and then processed into other forms for the production of batteries. (Credit: Jenny Nuss / Berkeley Laboratory)

The Department of Energy (DOE) is interested in both geothermal energy and the lithium supply chain, said Stringfellow, an expert in industrial waste treatment and management. “We have been commissioned by the Geothermal Technology Office of the DOE to conduct an independent analysis of mineral extraction technology in the context of geothermal power generation,” he said. “There have been previous reviews of individual fundamental processes, but this is, to our knowledge, the first comprehensive review that has examined the more applied side of the science of the process. “

Stringfellow and co-author Patrick Dobson, head of the geothermal systems program at Berkeley Lab, reviewed published literature and industry and government reports, and performed an in-depth review of lithium mining technology patents. The most technologically advanced lithium extraction method is lithium adsorption using inorganic sorbents, but other promising technologies are also in development. Inorganic molecular sieve ion exchange sorbents are applied for the extraction of lithium from brines, and the past and current application of this technology is discussed in the article.

Dobson and Stringfellow are members of the Lithium Resources Research and Innovation Center (LiRRIC), established at the Berkeley Lab to develop science and technology for the extraction, refining and synthesis of sustainable household lithium materials for applications such as batteries.

Recent projects have focused on how to determine the chemical composition of hot brine in real time, without the need to cool it, allowing better process control to maximize the efficiency of lithium extraction. They are also working on a techno-economic analysis with two companies operating in Salton Sea – Berkshire Hathaway Energy and Controlled Thermal Resources – to see if lithium mining technologies can be implemented in a way that makes them competitive with others. forms of lithium production. These efforts are supported by the California Energy Commission and the Advanced Manufacturing Office of the DOE.

“Berkeley Lab has pioneered lithium battery technologies and continues to be at the forefront of lithium battery innovation by utilizing natural resources and interacting equitably with the communities in which those resources reside,” said Mike Whittaker, director of LiRRIC.

The work was supported by the Geothermal Technology Office of the Department of Energy.

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Founded in 1931 on the conviction that the greatest scientific challenges are best met by teams, Lawrence Berkeley National Laboratory and its scientists have been awarded 14 Nobel Prizes. Today, researchers at the Berkeley Lab are developing sustainable energy and environmental solutions, creating useful new materials, pushing the boundaries of computing, and probing the mysteries of life, matter, and the universe. Scientists around the world rely on the laboratory facilities for their own scientific discoveries. Berkeley Lab is a national multi-program laboratory, operated by the University of California for the Bureau of Science of the US Department of Energy.

The DOE’s Office of Science is the largest supporter of basic research in the physical sciences in the United States and works to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science.

Additional information:

To catalyze solutions and partnerships around specific challenges to America’s energy storage future, Berkeley Lab is convening a National Energy Storage Summit. The National Energy Storage Summit, Jumpstarting America’s Energy Storage Future, will be open to the public and take place March 8-9, 2022.


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