- 07/07/2025
- Article
- Production
How does lithium extraction actually work? – Part 2
There are many ways to obtain the coveted metal lithium and its salts. Extraction from brine is completely different from extraction from lithium-containing minerals (see part 1 of our mini-series). Growing demand is driving the development of modern, environmentally friendly methods. The third important source is used batteries. Recycling processes currently cover at most ten percent of demand, but they have very high future potential.
Written by Dr. Ulla Reutner
Silicate rock, which is mined in Australia, the USA, Mexico and China, among other places, is only considered the second most important source of lithium worldwide. There are also some deposits in Europe, for example in Portugal, France, Serbia and in the German-Czech border region (Zinnwald/Cinovec) in the Ore Mountains. However, potential mining is being slowed down almost everywhere by citizens' initiatives that fear environmental damage. You can read about the process steps required to extract lithium carbonate and hydroxide from minerals in Part 1.
Nevertheless, Europe wants to continue to develop its own lithium sources in order to become less dependent on imports. Therefore, a second option, extraction from brine, is becoming increasingly important. Globally, lithium-containing brine is actually the number one source, accounting for 50 to 60 percent. However, huge white salt basins, known as salares, or shallow salt lakes, are rarely found here. These characterise lithium extraction in South America, in the so-called lithium triangle between Chile, Argentina and Bolivia, i.e. in dry, hot areas. In Europe, on the other hand, direct lithium extraction (DLE) is considered the most modern production process with the most promising future.
Lithium from underground salt lakes
So far, however, classic solar evaporation and precipitation have been more important worldwide. Three things are needed for this: lithium-containing brine, sun – and time. The basis for this are underground salt lakes. Pumps are used to pump the brine, which has a lithium ion content of 200 to 1500 mg/l, from a depth of between ten and 300 metres into evaporation basins or ponds, such as the Salar de Atacama. In addition to lithium salts, the brine contains a number of accompanying substances such as magnesium, sodium and potassium salts, chlorides, sulphates, borates, etc.
Direct solar energy heats the pumped brine, causing the water to evaporate and thus concentrating the solution further and further. Up to 97 percent of the water evaporates. This process takes from several months to two years. First, sodium chloride (halite) precipitates, followed by potassium and magnesium chloride as the concentration increases. Once the brine has been reduced to six to eight percent of its original volume, other accompanying substances are chemically removed, for example by adding lime milk, which precipitates calcium hydroxide.
Now comes the actual step of lithium extraction: sodium carbonate is added to the concentrated, purified brine. Lithium carbonate precipitates and is filtered out. After drying, it can be refined into battery-grade lithium carbonate (with a purity of over 99.5 percent) or converted into lithium hydroxide by reacting it with lime.
This form of lithium mining involves immense water consumption: almost 2,000 litres for 1 kg of lithium. And this in an area that is very dry. The salty brine cannot be used for irrigation or as drinking water. However, pumping it out also threatens freshwater supplies. If too much salt water is pumped out, it could flow back in and mix with the brine.
Lithium from thermal water
Processes that extract lithium from thermal water as a by-product of geothermal energy are considered more environmentally friendly. Such processes are particularly important in Central Europe. However, studies and pilot projects are also underway in California, Chile, New Zealand and Turkey to extract lithium from brine in geothermal-intensive regions. And there are other countries with geothermal lithium potential, such as Iceland, Italy and Japan.
The most advanced projects are at Salton Sea in California and the Upper Rhine Graben in Germany. With eleven active geothermal power plants, the area around Salton Sea is already well developed. Several lithium extraction projects are running in parallel there, including those by CTR and BHE Renewables. In the Upper Rhine Graben, the geothermal plants in Insheim and Landau use lithium-containing brine. There, the company Vulcan Energy is striving for a climate-neutral process for lithium production.
The projects mentioned all use direct lithium extraction (DLE), in which hot thermal water (around 150 °C) is first pumped up from a depth of approximately two to five kilometres. Typically, it consists of brine with a concentration of 200 to 230 mg/l. After the hot brine has been used for energy production, it is fed into a sorption system at the optimum process temperature. This system uses an ion exchange resin or adsorption material that adsorbs lithium on its surface and thus extracts it. The remaining brine is returned to the ground. The surface is then washed again with water or another suitable solution, drained and refined into a lithium chloride solution. The eluate can then be concentrated by membrane processes or evaporation. A-DLE, adsorption-based direct lithium extraction, was developed in the 1970s and has been in commercial use since 1996
Strategic project for ‘green’ lithium
Since April 2024, Vulcan has been producing initial quantities of a 40 per cent lithium chloride solution at its lithium extraction optimisation plant in Landau. It is further processed into battery-grade lithium hydroxide monohydrate (LHM) by electrolysis at Vulcan's central lithium electrolysis optimisation plant in the Höchst Industrial Park in Frankfurt. This plant has been in operation since November 2024. In addition to process optimisation, both plants are also used to produce initial product quantities for quality testing. The subsequent commercial plant in Höchst is expected to produce around 24,000 tonnes of lithium annually in the future. Under the European Commission's Critical Raw Materials Act (CRMA), Vulcan's first project phase for the combined production of lithium and renewable energies (Lionheart) was classified as a ‘strategic project’ in March 2025.
DLE can also be used to extract lithium from salar brine – as a more environmentally friendly and efficient alternative to evaporation. This is already established industrially in Argentina and China, among other places. In addition, certain DLE variants can be used to extract lithium from industrial or mining wastewater, which is being tested in China and the USA, among other places.
Lithium could also be extracted from seawater. The amount in the oceans is estimated at 230 billion tonnes. However, this huge deposit is difficult to exploit. The concentration is around 0.17 mg/l – that is around 1000 times less than in salar brines. Despite intensive research, especially in Japan, Korea and China, extraction does not currently appear to be economically viable. The outlook is somewhat more positive for seawater desalination plants.
Used batteries – a lithium source that should not be underestimated
Used batteries (lithium-ion batteries, LIB) are a source of battery-grade lithium that should not be underestimated. This is where development is booming. Current recycling processes can already recover up to 70 percent of the lithium. But before recycling comes return. The EU has a battery directive that says batteries should be reused, reprocessed or recycled at the end of their life. While almost half (47 percent) of all portable batteries sold in the EU were collected for recycling in 2019, the target for 2030 is 73 percent. For light batteries, the target collection rate is 61 percent by 2031. The target for the minimum amount of lithium recovered is 6 percent. There is hardly a renowned technical research institute that is not taking on this challenge. Chemical companies and specialised medium-sized companies are also working on recycling lithium batteries as effectively and sustainably as possible. Last but not least, numerous automotive companies are setting out to promote battery recycling.
Some examples:
- Karlsruhe Institute of Technology (KIT)/Helmholtz Institute Ulm, EnBW: Development of a recycling process that combines mechanical processes (grinding) and chemical reactions. Up to 70 percent lithium recovery.
- Duesenfeld GmbH, Germany: Combination of mechanical, thermodynamic and hydrometallurgical processes. The lithium-containing black mass is further processed in a pilot plant at Fraunhofer IKTS. 95 percent of the lithium is recovered from this, with a purity of 99.8 percent.
- Mercedes Benz: first European battery recycling plant owned by an automobile manufacturer, opening in 2024 in Kuppenheim, southern Germany: integrated mechanical-hydrometallurgical process. (We reported.)
- Start-up Cylib: Recycling plant for electric car batteries currently under construction in Dormagen. Commissioning planned for 2026. Process steps after dismantling: mechanical, thermal, water-based.
- BASF: first commercial battery recycling plant in Schwarzheide for processing black mass, in operation since June 2025. As with Cylib, nickel, cobalt and manganese are chemically recovered in addition to lithium.
The VDI Centre for Resource Efficiency lists further recycling processes on its website. It also provides information on further developments, opportunities and funding programmes for circular economy innovations in batteries and accumulators.
Recycling infrastructures typically arise in the vicinity of battery material or battery cell manufacturers and car manufacturers – especially in central and eastern Germany, Hungary, northern France and Scandinavia. The trend in Europe is towards hub and spoke structures, in which used batteries are collected decentrally (spokes) and processed in central hubs. Currently, more than 30 projects are planned or under construction. A total capacity of around 330,000 tonnes per year is expected by 2026. The recycling industry will then be equipped to handle the expected return of used batteries from electric cars.
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