Mining companies are showcasing new technologies which they say could extract more lithium – a key ingredient for electric vehicle (EV) batteries – from South America’s vast, dry salt flats with lower environmental impacts.

But environmentalists question whether the expensive technology is ready to be rolled out at scale, while scientists warn it could worsen the depletion of scarce freshwater resources in the region and say more research is needed.

The “lithium triangle” – an area spanning Argentina, Bolivia and Chile – holds more than half of the world’s known lithium reserves. Here, lithium is found in salty brine beneath the region’s salt flats, which are among some of the driest places on Earth.

Lithium mining in the region has soared, driven by booming demand to manufacture batteries for EVs and large-scale energy storage.

Mining companies drill into the flats and pump the mineral-rich brine to the surface, where it is left under the sun in giant evaporation pools for 18 months until the lithium is concentrated enough to be extracted.

The technique is relatively cheap but requires vast amounts of land and water. More than 90% of the brine’s original water content is lost to evaporation and freshwater is needed at different stages of the process.

One study suggested that the Atacama Salt Flat in Chile is sinking by up to 2 centimetres a year because lithium-rich brine is being pumped at a faster rate than aquifers are being recharged.

Lithium extraction in the region has led to repeated conflicts with local communities, who fear the impact of the industry on local water supplies and the region’s fragile ecosystem.

The lithium industry’s answer is direct lithium extraction (DLE), a group of technologies that selectively extracts the silvery metal from brine without the need for vast open-air evaporation ponds. DLE, it argues, can reduce both land and water use.

Direct lithium extraction investment is growing

The technology is gaining considerable attention from mining companies, investors and governments as a way to reduce the industry’s environmental impacts while recovering more lithium from brine.

DLE investment is expected to grow at twice the pace of the lithium market at large, according to research firm IDTechX.

There are around a dozen DLE projects at different stages of development across South America. The Chilean government has made it a central pillar of its latest National Lithium Strategy, mandating its use in new mining projects.

Last year, French company Eramet opened Centenario Ratones in northern Argentina, the first plant in the world to attempt to extract lithium solely using DLE.

Eramet’s lithium extraction plant is widely seen as a major test of the technology. “Everyone is on the edge of their seats to see how this progresses,” said Federico Gay, a lithium analyst at Benchmark Mineral Intelligence. “If they prove to be successful, I’m sure more capital will venture into the DLE space,” he said.

More than 70 different technologies are classified as DLE. Brine is still extracted from the salt flats but is separated from the lithium using chemical compounds or sieve-like membranes before being reinjected underground.

DLE techniques have been used commercially since 1996, but only as part of a hybrid model still involving evaporation pools. Of the four plants in production making partial use of DLE, one is in Argentina and three are in China.

Reduced environmental footprint

New-generation DLE technologies have been hailed as “potentially game-changing” for addressing some of the issues of traditional brine extraction.

“DLE could potentially have a transformative impact on lithium production,” the International Lithium Association found in a recent report on the technology.

Firstly, there is no need for evaporation pools – some of which cover an area equivalent to the size of 3,000 football pitches.

“The land impact is minimal, compared to evaporation where it’s huge,” said Gay.

The process is also significantly quicker and increases lithium recovery. Roughly half of the lithium is lost during evaporation, whereas DLE can recover more than 90% of the metal in the brine.

In addition, the brine can be reinjected into the salt flats, although this is a complicated process that needs to be carefully handled to avoid damaging their hydrological balance.

However, Gay said the commissioning of a DLE plant is currently several times more expensive than a traditional lithium brine extraction plant.

“In theory it works, but in practice we only have a few examples,” Gay said. “Most of these companies are promising to break the cost curve and ramp up indefinitely. I think in the next two years it’s time to actually fulfill some of those promises.”

Freshwater concerns

However, concerns over the use of freshwater persist.

Although DLE doesn’t require the evaporation of brine water, it often needs more freshwater to clean or cool equipment.

A 2023 study published in the journal Nature reviewed 57 articles on DLE that analysed freshwater consumption. A quarter of the articles reported significantly higher use of freshwater than conventional lithium brine mining – more than 10 times higher in some cases.

“These volumes of freshwater are not available in the vicinity of [salt flats] and would even pose problems around less-arid geothermal resources,” the study found.

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Dan Corkran, a hydrologist at the University of Massachusetts, recently published research showing that the pumping of freshwater from the salt flats had a much higher impact on local wetland ecosystems than the pumping of salty brine. “The two cannot be considered equivalent in a water footprint calculation,” he said, explaining that doing so would “obscure the true impact” of lithium extraction.

Newer DLE processes are “claiming to require little-to-no freshwater”, he added, but the impact of these technologies is yet to be thoroughly analysed.

Dried-up rivers

Last week, Indigenous communities from across South America held a summit to discuss their concerns over ongoing lithium extraction.

The meeting, organised by the Andean Wetlands Alliance, coincided with the 14th International Lithium Seminar, which brought together industry players and politicians from Argentina and beyond.

Indigenous representatives visited the nearby Hombre Muerto Salt Flat, which has borne the brunt of nearly three decades of lithium extraction. Today, a lithium plant there uses a hybrid approach including DLE and evaporation pools.

Local people say the river “dried up” in the years after the mine opened. Corkran’s study linked a 90% reduction in wetland vegetation to the lithium’s plant freshwater extraction.

Pia Marchegiani, of Argentine environmental NGO FARN, said that while DLE is being promoted by companies as a “better” technique for extraction, freshwater use remained unclear. “There are many open questions,” she said.

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Stronger regulations

Analysts speaking to Climate Home News have also questioned the commercial readiness of the technology.

Eramet was forced to downgrade its production projections at its DLE plant earlier this year, blaming the late commissioning of a crucial component.

Climate Home News asked Eramet for the water footprint of its DLE plant and whether its calculations excluded brine, but it did not respond.

For Eduardo Gigante, an Argentina-based lithium consultant, DLE is a “very promising technology”. But beyond the hype, it is not yet ready for large-scale deployment, he said.

Strong regulations are needed to ensure that the environmental impact of the lithium rush is taken seriously, Gigante added.

In Argentina alone, there are currently 38 proposals for new lithium mines. At least two-thirds are expected to use DLE. “If you extract a lot of water without control, this is a problem,” said Gigante. “You need strong regulations, a strong government in order to control this.”

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Efforts to green lithium extraction face scrutiny over water use