High in the Andes mountains where the borders of Argentina, Bolivia, and Chile intersect, white expanses of salt stretch for thousands of kilometers. Under these flats lie reservoirs of brine that contain upwards of 58 percent of the world’s lithium.
For decades, producers have extracted that lithium by pumping the water up to the surface and letting it evaporate until the lithium salts become concentrated enough to filter out. The process takes 12 to 18 months, leaving behind piles of waste containing other metals. It also evaporates nearly 2 million liters of local water resources, harming indigenous communities.
With the EV and energy-storage markets accelerating, demand for lithium will increase over 20 times by 2040, according to CleanTech Lithium. To keep up, many companies are now developing processes to chemically or physically filter out lithium from brines and inject the brine back underground. These direct lithium extraction (DLE) technologies take hours instead of months and could double the production of lithium from existing brine operations. Much as shale extraction did for oil, DLE is a “potential game-changing technology for lithium supply,” because it could unlock new sources of lithium, according to a recent report by Goldman Sachs. But in contrast to shale’s fracking risks, DLE brings environmental benefits, reducing land and water use, and waste.
“We pump up the brine, take out only lithium, and put the brine back underground,” says Jeremy Patt, chief technology officer at Calgary-based Summit Nanotech. “The goal is to not add any chemicals or change the temperature or pH of the brines. So you get more lithium out with minimal disruption.”
At Summit Nanotech’s direct-lithium-extraction pilot plant in Chile’s Atacama Desert, tanks behind the equipment trailer hold six pilot-program customers’ brines for lithium extraction.Summit Nanotech
Summit is one of more than a dozen young companies piloting new DLE processes with the intent of commercial production as early as 2025. The world’s top lithium producers, Albemarle and SQM, plan to test their own DLE technologies this year. In China, a handful of commercial projects already use Chinese DLE innovator Sunresin’s technology.
Carmakers, meanwhile, are lining up to secure DLE lithium supplies: GM is backing Austin, Texas–based EnergyX and Tesla’s lithium supplier Livent, which has a DLE facility in Argentina, while BMW buys lithium from Livent and has invested in California startup Lilac Solutions. Chile’s announcement in April that all new lithium projects from private partners will have to speed up the commercialization of DLE technologies.
Most DLE projects today rely on adsorption. The idea is to trap lithium molecules on the surfaces of tiny beads made of carefully chosen materials and physical structures. Most companies today use a variation of the aluminum adsorbents first invented 60 years ago.
Summit Nanotech’s aluminum-based particles are highly porous, and their surface is designed to interact electronically with lithium ions, explains Patt. The pores have diameters comparable to lithium ions, which help it grab over 90 percent of lithium from brine; traditional evaporation recovers between 40 and 65 percent. Summit pumps brine through columns tens of feet tall and several feet wide that are packed with the sorbent. Once the adsorbent is loaded with lithium, the metal is washed off with warm water, leaving the sorbent to be reused and the water to be recycled. “Our proprietary sorbent and water-recovery process are our two big technology pillars,” Patt says.
In the five years since it was founded, Summit has ramped up its technology and incorporated it into a pilot plant in Santiago, Chile, to which it brought the brine in trucks, he says. It is now building a demonstration plant that will process 25 cubic meters of brine per day and is drawing up plans for its first commercial plant.
Livent and SunResin use their own aluminum sorbents. Three Chinese lithium producers have been using SunResin’s technology since 2017, and five more projects are underway, according to Goldman Sachs.
Livent, however, was the first, having deployed DLE commercially back in 1998. The company concentrates brines in small ponds before running them through the DLE process, using less land and water than traditional evaporation ponds. The company increased production to 27,000 metric tons a year in 2019, and plans to produce another 50,000 metric tons a year by 2026.
California startup Lilac Solutions is taking a different approach to DLE called ion exchange. The company uses tiny beads that look just like adsorbent beads but behave entirely differently, says CEO David Snydacker. The beads absorb lithium in exchange for a hydrogen ion. Then the company uses a dilute acid to flush out the lithium.
Ion exchange is a common process, used for everyday purposes such as in home water softeners. But developing an ion-exchange material for lithium has “been a Holy Grail,” says Snydacker. “For 20 years, large companies have been trying to make ion exchange work.” Only ceramic materials can absorb lithium with high selectivity, but the challenge is to make a durable ceramic that can survive brine and acid washes. Although previous ceramic ion-exchange materials have degraded after only 10 cycles, he says, Lilac’s material lasts for more than 2,000 cycles.
Australian lithium developer Lake Resources is now piloting Lilac’s technology at two remote project sites, and Ford has signed a deal to buy 25,000 metric tons of lithium a year from one of these projects. Snydacker says Lilac is installing a third pilot plant at “one of largest lithium resources in the world,” and it will announce other large customer projects in the coming months.
Oil and gas companies in Canada and the United States regularly pull up lithium-laced saltwater, but these waters contain only 30 to 40 milligrams of lithium in a liter, a mere 3 to 4 percent as much as the brines in Chile contain. That’s just too little for today’s adsorbents to nab, says Alex Wylie, president and CEO of Calgary startup Volt Lithium.
Volt Lithium’s pilot-plant-facility equipment treats brine prior to entering into the direct lithium extraction (DLE) process.Greg Huszar/Volt Lithium
To tap into these oil-field brines, Volt Lithium has developed 5-micrometer-wide beads of a lithium-adsorbing compound that they expose to brines from which they first remove other contaminants. The beads are far smaller than the particles that other companies use, he says, “so we have 800 times more surface area, and that’s allowing us to extract from low concentration waters.”
Recent pilot tests for Volt’s Rainbow Lake Lithium Project in Northwest Alberta show that the material can extract 90 percent of lithium from water with concentrations as low as 34 milligrams per liter. The testing was conducted at the company’s pilot plant operations in Regina, Saskatchewan. Volt Lithium is now building a demonstration plant that will test brines from across North America, says Wylie.
The company’s team, which includes several oil and gas industry alumni, focused on oil-field brines. “The infrastructure is already in place,” he says. “That’s such a big deal. Lithium in that brine is being produced every day, it’s just not being extracted.”
Heavyweights in the oil and gas industry are starting to branch out into lithium, according to the Financial Times. ExxonMobil recently purchased salty brine deposits containing lithium in Arkansas, and Chevron is also looking at producing lithium.
The ability to tap into diverse domestic sources of lithium is of special interest to the United States government, says Holly Stower, an analyst at the Cleantech Group. “As the U.S. transitions to a low-carbon economy, the Department of Energy wants to ensure that they have steady and secure lithium supply that is resilient to geopolitical risk, and DLE enables that,” she says.
The DOE is investing millions in new DLE technologies to extract lithium from geothermal brines in the United States, such as the Salton Sea in California, which the National Renewable Energy Laboratory estimates could provide over 24,000 metric tons of lithium a year. The DOE’s biggest purse of US $5 million has gone to EnergyX, which also has $50 million from General Motors. The company is using a mix of technologies that include adsorption and a patented nanotechnology membrane that can almost instantly separate lithium in a day or two.
Which technology for DLE will win is still unclear. There is as yet “no clear winner in terms of what customers want and what the technology can provide,” she says. But all the DLE separation technologies being piloted now are already used for other purposes, says Goldman Sachs analyst Hugo Nicolaci, and that should speed up commercialization. “Expect the first real wave of DLE projects from later in the decade.”
Update: 6 Dec. 2023: The story was updated to correct the name and spelling of CleanTech Lithium and to clarify further aspects of the direct lithium extraction process