Demand for lithium is increasing and pricing agency Benchmark Mineral Intelligence (BMI) expects a million-ton lithium materials market by 2024 and a compound annual growth rate of 15% through 2033.
Analysts including BMI anticipate the onset of a lithium shortage around 2029, amid environmental and political concerns about the required expansion of lithium mining and processing and its concentration in a small number of countries.
Lithium is largely produced via evaporation of brine in the open air – in the ‘lithium triangle’ of South America – or from hard rock mining, mainly in Australia. China, which processes that Australian material, has domestic mining capacity based on bluestone and brine. BMI estimates that 34% of lithium is mined in Australia, 28% in South America and 20% in China.
Energy-intensive hard rock mining relies on diesel mining equipment and high-temperature processing. Brine concentration and processing via evaporation, while CO2 emissions are lower2 emissions, is water intensive in arid areas, raising concerns about the overuse of aquifers. The resulting resistance to projects means that the lithium mining industry is slow to respond to fluctuations in demand.
Direct lithium extraction
Direct lithium extraction (DLE) approaches offer an alternative by extracting lithium from brine using thermal or chemical processes. BMI estimates that the method is responsible for 4% of current lithium and will reach 12% by 2030.
“Some commercial projects have been underway for years,” said Federico Gaston Gay, lead lithium analyst at BMI. “Now there is renewed interest. Mining and oil and gas companies are looking at DLE and they have the money and expertise to develop it.”
Water used during DLE can be returned to aquifers. DLE processes are typically powered by electricity and in some cases the same brine solutions can also be used for geothermal energy generation.
“Our approach to DLE means there is minimal water depletion from the underground aquifer and, if used with renewable energy as we plan, there will be minimal emissions associated with the operations,” said Steve Kesler, executive chairman and interim CEO at Cleantech Lithium. (CTL). The company is ramping up DLE projects in Chile and operates a pilot processing plant that produces eluate that is processed by a third party into battery-grade lithium carbonate, ready for testing by battery suppliers.
Gaston Gay noted that while there is potential, the industry’s claims of reduced environmental impact still need to be proven. “In most cases, brine is re-injected, so in theory the balance of the aquifer does not change,” he said. “DLE operations also take up a fraction of the land needed for evaporation ponds. These differences can make a big difference to environmental performance, but there is not enough information available to definitively say it is cleaner.”
The largest of CTL’s planned extraction sites, Laguna Verde, is estimated to contain approximately 1.8 million tonnes of lithium carbonate equivalent. Initial drilling and a pre-feasibility study are underway, after which CTL will seek investors, offtake partners and debt financing to cover the estimated $450 million construction cost for a full DLE plant at the site.
The production costs of DLE can vary widely depending on the composition, temperature and depth of the brine, as well as other conditions at a project site and the specific technology used. CTL’s Kesler said he expects the company’s projects to have “relatively low costs” compared to other lithium mining operations. Gaston Gay, meanwhile, noted that DLE’s costs should compare favorably with bluestone mining. However, unlike conventional brine extraction, DLE replaces natural evaporation in the sun with a more energy-intensive process. Further treatments may be required before or after the extraction, which can also lead to potentially higher costs.
New tricks
Although DLE processes are commercially proven and already in use, scaling to a larger market share will require new technology and applications. Gaston Gay noted that operational projects in Argentina and China are an improvement on conventional evaporation rather than a completely new process, and that dramatic scale-up of any process is likely to be fraught with complications.
In a 2023 article published in Nature reviews Earth and environmentScientists led by Argentina’s National University of Jujuy divided DLE technology into seven broad categories at different levels of commercial development. “Some proposed DLE approaches, such as ion pumps or Li+ [lithium]selective membranes are completely new and will require more technical efforts to reach industrial scale,” wrote lead author Maria L. Vera. “Conversely, other proposals, such as ion exchange, solvent extraction or electromembrane processes, have been studied for decades… the challenge here is to adapt these methodologies to the complexity of lithium-rich brine solutions.”
CTL says it has chosen one of the better-known processes as a benchmark for risk reduction. “The purification technology has been around for many years, in multiple industries, including uranium and water treatment, so there is relatively little technology risk in the process,” Kesler said. “We have also sought to mitigate that risk by working with some of the most respected names in the industry.”
The availability of technological options should also make DLE more adaptable to different site conditions. “For example, at Laguna Verde we tested different adsorbents to understand which one works best with our brine in terms of selectivity of lithium molecules and repulsion of other minerals,” Kesler added. “Not all brines are the same. It is a matter of continuing to work and optimizing the process and technology, instead of having to reinvent something.”
Diversified offering
Another reason for the recent fuss surrounding DLE is its potential to significantly increase the amount of lithium available for extraction. For existing brine projects, BMI estimates that improved process efficiency with DLE could increase yields by as much as 670,000 tons per year. The process could also bring lithium mining to several new regions.
Vera et al. It is estimated that 50% to 85% of lithium-rich continental brines are located in the lithium triangle region, with China being the second largest source. Geothermal brine and oilfield brine, with a lower lithium concentration, are found in many more regions, but are not considered viable because evaporation to the required concentration would take too long, or the deposits are in regions without sufficient land or a suitable climate for open air. evaporation.
There are several DLE test projects underway in Europe, of which Vulcan Energy Resources’ sites in Germany are among the most advanced. The first phase of Vulcan’s project is expected to produce 24,000 tonnes of lithium hydroxide per year and the company has signed supply agreements with a number of battery industry customers from 2025.
Vulcan’s project, located in Germany’s Upper Rhine Valley, combines DLE with a geothermal power plant. Brine water from various drilling locations is led to the factory. The heat from the brine is used to generate electricity and the brine is then treated to produce a precursor: lithium chloride suspended in water. This will then be transported by truck to a site near Frankfurt, where it will be further processed via electrolysis to produce battery-quality lithium hydroxide.
Horst Kreuter, co-founder and chief representative of Vulcan Energy Resources, said the first geothermal cluster has started producing lithium chloride, which is being held in storage pending the completion of the electrolysis plant.
Vulcan has exploration permits for further drilling sites around the Upper Rhine Valley and says the electrolysis plant could also be used to process brine shipped from further afield. “The electrolysis plant cost about $30 million to build, so you can’t put one in every location,” Kreuter said. “The installation is very flexible, we can add different pre- and post-treatments and can work at different temperatures and pressures. We are planning ahead and starting to look at other parts of Europe as well.”
There are many other areas in Europe worth exploring for brines that could be suitable for DLE. In the South West of the UK, Cornish Lithium is working on several projects and is targeting 15,000 tonnes of DLE production across multiple small sites by 2030.
Compared to the project in Germany, Cornish Lithium expects to find brine at lower temperatures and lower lithium concentrations. A temperature of about 80 C is too low for geothermal energy, but can be sufficient to provide the local area with district heating. Due to the lower concentration in the brine, the project may also be able to use cheaper extraction processes and therefore scale up more quickly.
“Cornish brine is very clean – it is even less salty than seawater,” says Neil Elliot, corporate development manager at Cornish Lithium. “Our most recent exploration found lithium concentrations of more than 100 parts per million. This means that we can look at membrane technologies and various other concentration techniques.” Working with membrane technology, such as reverse osmosis often used in water desalination, means DLE could also potentially provide clean water to local communities.
Hard rock alternative
In addition to the DLE project, Cornish Lithium is developing hardrock lithium mining at another site in Cornwall, which is expected to produce a further 10,000 tonnes of lithium hydroxide per year by 2030.
The company plans to redevelop a disused china clay pit and build a processing plant within a kilometer of the site. The materials mined at the site may be processed very differently to the spodumene mineral typically mined in Australia. Cornish Lithium has worked with Australian company Lepidico to develop a suitable process. Life cycle assessments conducted for Lepidico’s project estimate a 40% reduction in carbon emissions compared to typical hardrock lithium mining. “Normally on a bluestone project you have to roast the ore at temperatures above 1,000 C,” says Elliot. “Instead, we use a chemical process developed by Lepidico that uses sulfuric acid to produce lithium.”
That route should also allow the company to produce battery-grade lithium hydroxide at the same site without further shipping or processing. “The idea is that we will arrive at a final product in Cornwall that we can ship directly to users in the battery industry,” said Elliot.
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