Determining the most optimal method of lithium extraction is hotly contested; in this report, industry experts Lithium Power International address the sustainability of currently used extraction techniques.
Lithium extraction has traditionally been conducted in two main ways: crystallised in large evaporation ponds from brine pumped from underground aquifers or refined from ore blasted from rock outcrops and shallow pits. Some lithium is liberated from clay, but not much.
Now that lithium is in significant demand for electric vehicles and storage in battery farms, more efficient means of lithium extraction are being introduced. One of the main ones is direct lithium extraction, otherwise known as DLE.
The potential of direct lithium extraction
The benefits of direct lithium extraction are compelling for new brine projects, such as Lithium Power International’s (LPI) Maricunga project in Chile’s vaunted Lithium Triangle. Producers are enticed by significantly lower capital outlays, quicker project development times, lower operating costs because lithium extraction times are slashed to weeks rather than years, earlier revenue streams, and significantly greener credentials. All these factors probably mean that the financial and environmental advantages are likely to herald the end of new, large-scale evaporation ponds that until now have been industry best practice. New DLE processes are compelling even in the Lithium Triangle, where evaporation rates are the highest in the world thanks to its dryness and elevation above sea level.
This gives hope to environmental advocates, who have been campaigning for a number of years against the lithium extraction of brine because of the potential environmental damage they say can be caused to aquifers. Chile’s largest lithium producer, Sociedad Quimica y Minera (SQM), recently pledged that no more brine would be used in its operations for future lithium expansions. Pressure is now on the industry to improve their green credentials.
The Maricunga lithium project
A partnership was announced in May this year by LPI and its project partners in the Maricunga lithium project, which is also situated in Chile’s Lithium Triangle. It involves a strategic alliance with Mitsui & Co Ltd whereby it would introduce leading-edge, efficient, and environmentally friendly technologies for processing brine. The agreement noted that Mitsui’s new technology was being studied and tested. The project partners would also collaborate with Mitsui for the development of other lithium related businesses in Chile “by introducing efficient and environmentally friendly” processing technologies. This also includes collaboration with Mitsui’s technical partner to facilitate the development and testing of the DLE technology at Maricunga to provide a broader platform to promote the technology.
A definitive agreement is still to be finalised and, until due diligence and terms are completed, no more information has been released. But LPI’s Chief Executive Officer, Cristobal Garcia-Huidobro, said the agreement was comprehensive and set a framework for the high-grade Maricunga project to proceed. “We look forward to working with (Mitsui) on mutually beneficial lithium projects and positive outcomes for the Chilean lithium industry.”
Diversity of extraction techniques
A debate is occurring among producers as to the best lithium processing solution to follow. What works well in one location might not be as good elsewhere. Geological, political, and economic issues come into play as well. Research group Fitch Solutions noted recently that pressure from governments and investors would motivate existing lithium producers to alter their production techniques. It said environmental, social, and governance (ESG) conscious investors would change the way they conducted business. “More than half of the global lithium reserves are within what is referred to as the Lithium Triangle, covering parts of Argentina, Chile, and Bolivia. Historically, lithium extraction within salt flats of the Lithium Triangle has been substantially water-intensive, requiring about two million litres of water per tonne of lithium extracted. This presents a substantial risk of water shortages for future agricultural needs in a region that already has a reputation as one the driest places on the globe.”
Producers are working hard to develop long term solutions. One of the world’s largest lithium producers, Albemarle Corporation from the US, has been studying how to develop its Magnolia project in Arkansas, which is seeking to tap oilfield brines. Its chairman, president and CEO, Jerry Kent Masters, recently told investors it was possible that direct lithium extraction would be used. But he also described it as a mechanical operation that would only be applied to a resource of lower quality or that had higher impurities. He noted some drawbacks had to be overcome, including the consumption of a lot of water and energy.
Livent is another established lithium producer, and it has used direct lithium extraction for a number of years. Its president, CEO, and director, Paul Graves, says that some forms of the technology can work. But he cautions about it being a technology that can quickly be adopted or used in all circumstances. “There are many, many ways of doing it and they don’t all work everywhere. So, lining up your DLE technology with the resource that you have is really the critical point. You can have a solvent-based DLE technology that is very rapid, but it’s clearly never going to be given an environmental permit down there in South America. You can have other DLE structures that are very good in high-concentration, low impurity brines but don’t work with specific impurities. I think it will unlock some resources. The economics behind DLE are probably more favourable than the technical changes.”
Graves also noted that Livent’s direct lithium extraction plant in Argentina was something of a hybrid. “We concentrate the brine very quickly, within hours, to a useable level. But a small amount of time in a pond massively increases the concentration through evaporation.” He added that most of Livent’s technology investment had been on reducing water usage. “We have some pretty interesting projects underway today that could, by the look of things, massively reduce the pond footprint and may even eliminate the pond footprint for future expansions. The cost won’t really change, and it won’t necessarily improve our yields. It’s really about improving the sustainability footprint, which is really important.”
There are clearly pros and cons associated with the wholesale adoption of direct lithium extraction to be weighed up before investment decisions can be made. And it may not be necessary to back one technology and not another. That will depend on factors like costs, technology developments, evaporation rates, environmental controls, social imperatives, and the chemical composition of the brine.
The UK’s Cornish Lithium has recently completed construction of a water testing unit to trial direct lithium extraction technologies. It wants to know how to compare different systems to see which ones can achieve low-carbon extraction from geothermal waters. If all goes well, the company says it will develop a larger pilot plant in 2022 before committing to a commercial operation.
Standard Lithium is trialling a different technology at a demonstration plant at its Lanxess bromine facility near El Dorado in Arkansas. It has installed 700 monitoring stations to provide design and engineering data for a larger commercial DLE facility. It claims that its project, in the well-known Smackover brine region, has a 3.94 million tonne lithium carbonate equivalent resource and is the largest and most advanced project in the US. It is aiming to use its so-called LiSTR Direct Lithium Extraction technology, which it says could reduce the recovery time of extracting brine from a year to several hours. It would have a small footprint when compared with evaporation ponds.
There are many other groups also looking at new methods of lithium extraction at lower costs, with smaller environmental impacts and in parts of the world closer to ends markets – particularly the US. An Australian company, Controlled Thermal Resources (CTR), claims a direct extract technology with a small physical footprint and little by way of carbon emissions. It is testing groundwater from the Salton Sea in California, which is a vast source of brine. General Motors made a multi-million-dollar investment in CTR in recent weeks and wants to buy any lithium that can be produced from the Salton formations. A GM executive vice president, Doug Parks, told CleanTechnica recently that: “By securing and localising the lithium supply chain the US, we’re helping to ensure our ability to make powerful, affordable, high mileage EVs while also mitigating environmental impact and bringing more low-cost lithium to the market as a whole.” CTR plans to be producing lithium on a commercial scale by 2024.
There are other massive names involved in similar, early-stage work. In June, drilling contractor Schlumberger and Panasonic Corp announced they were seeking to validate and optimise an “innovative and sustainable lithium extraction and production process” in Nevada. Few details were given, other than saying a “differentiated direct lithium extraction process” would be used to produce high purity, battery-grade lithium while reducing production time from more than a year to weeks.
A month earlier, a division of chemicals company DuPont Water Solutions said it had a deal with Australia’s Vulcan Energy to test a lithium hydroxide extraction process from geothermal brine in the Upper Rhine Valley in Germany. It aims to extract the brine, upgrade it to a high purity hydroxide and produce geothermal energy. The heat from the extraction process would power the system. Any surplus would be turned into electricity, then sold into the grid to provide a zero-carbon footprint.