Researchers create method to extract lithium from hot deep water

Lithium, a lightweight metal used in the batteries of many Internet of Things (IoT) devices, has become an even more indispensable element because of growing demand in recent times. Until now, Europe has relied on imports. However, there are European lithium deposits in hot springs a few kilometres deep with high concentrations of lithium ions. A new extraction method developed by researchers at the Karlsruhe Institute of Technology (KIT) in Germany promises to extract lithium from hot deep water by accumulating lithium ions on the surface of porous solids.

“Depending on the geological origin, geothermal brines contain between 0.1 and 500 milligrams of lithium per litre. However, the extraction of lithium from geothermal brines represents a major challenge because lithium ions compete with other ions,” explains Professor Helmut Ehrenberg, Head of the Institute for Applied Materials at KIT. Lithium concentrations of up to 240 milligrams per litre were measured in the North German Basin and up to 200 milligrams per litre in the Upper Rhine Graben.

The novelty requires suitable adsorbents that are not only selective to lithium, but can also be produced, used and disposed of in an environmentally friendly manner. In addition, suitable desorption solutions are required to re-release the lithium ions from the adsorbent.

To overcome this challenge, a screen was developed based on a lithium-manganese oxide with a special crystalline structure of the spinel type. The researchers produced it by means of hydrothermal synthesis, in which substances crystallize from aqueous solutions at high temperatures and pressures.

In laboratory tests, the research team used this substance to adsorb lithium ions from geothermal brine. The brine came from the Bruchsal geothermal power plant operated by EnBW located in the Upper Rhine Graben. There, EnBW’s Research and Development department is investigating the extraction of lithium from the hot springs in various projects.

The researchers tested various desorption solutions after lithium adsorption, with acetic acid producing the best results in terms of lithium extraction and preservation of the adsorbent. However, with all the desorption solutions tested, especially with acetic acid, the lithium ion sieve was enriched with competing ions. This is due to the high mineral content of the brine in Bruchsal. Enrichment with competing ions may decrease the adsorption capacity of lithium.

The next challenge is to further improve the lithium ion sieve so that it is easier to handle, and so that its adsorption capacity is slightly affected during the process.

The expectation is that with this new process, the extraction of lithium from geothermal brines will support the development of a European lithium source in the future.

The research was published in the journal Energy Advances and added to the journal’s “Energy Advances – 2022 Outstanding Papers” collection.

BATTERY 2030+

Europe maintains the Battery 30 initiative for large-scale, long-term research whose aim is to promote the development of sustainable batteries of the future through innovative technologies and thus create competitive advantage throughout the battery value chain and also enable Europe to achieve the climate-neutral society targets of the European Green Pact.

The initiative has €272 million from the European Commission to improve and accelerate battery research and production over the period 2020-2023, with likely continuity to achieve medium and long-term goals. It consists of seven completed projects: a coordination and support action coordinated by UU in Sweden, and six research and innovation projects – BAT4EVER, coordinated by VUB, in Belgium; BIG-MAP, coordinated by DTU in Denmark; HIDDEN, coordinated by VTT in Finland; INSTABAT, coordinated by CEA in France; SENSIBAT, coordinated by IKERLAN in Spain, and SPARTACUS, coordinated by Fraunhofer in Germany.

Lithium dependency

Lithium is classified by the European Union as an “essential raw material” in the transition from fossil fuels to cleaner energy desired by the bloc. It is expected that by 2050, European demand for lithium will be 57 times what it is today.

Chile and Australia are the main lithium suppliers worldwide. China also has much of this element, but above all, when it comes to raw material supply chains, Chinese dominance dominates. China also dominates the field of battery and solar panel manufacturing and is the global leader in the refining of key raw materials that turns impure minerals into usable components not only in China but around the world, including Europe.

The European fear is that, along the lines of what happened when Russia stopped gas supplies in retaliation for sanctions against the war in Ukraine, the same will happen in relation to China, which may use its dominant role in the supply of raw materials to exert similar pressure in the future. China currently holds about an 80-90 percent monopoly in lithium refining, according to the European Union’s Department of Industry.

In March, the European Commission proposed a comprehensive set of actions to ensure the bloc’s access to secure, diverse, affordable and sustainable supplies of essential raw materials.