Is Direct Lithium Extraction the answer to satisfying the growing demand for lithium?

Global demand for lithium is growing as it is needed to produce virtually all batteries currently used in electric vehicles (EVs) as well as consumer electronics. Lithium-ion batteries are widely used in many other applications as well, but will supply keep pace with demand? The International Energy Agency is projecting a 15-fold increase in lithium demand by 2040 based on what would happen if governments made rapid progress towards reducing emissions by mid-century.

Despite expectations that lithium demand will rise from approximately 500,000 metric tons of lithium carbonate equivalent in 2021 to some three million to four million metric tons in 2030, apart from increasing the conventional lithium supply, which is expected to expand by over 300% between 2021 and 2030, direct lithium extraction (DLE) and direct lithium to product (DLP) may be the driving forces behind the industry’s ability to respond more swiftly to soaring demand, as well as reducing the industry’s environmental, social, and governance (ESG) foot­print, and lowering costs (McKinsey & Co).

Currently, around 98% of production is from lithium mining in Australia, Latin America, and China. New technologies expected to boost recovery and capacity include conventional brines with concentrations of between 200 and 2,000 parts per million (ppm), as well as hard-rock assets, where grades of 0.4 to 1.0 percent lithium are common.

Additional potential could come from unconventional deposits: geothermal and oilfield brines with grades of 100 to 200 ppm. The first option focuses on providing both clean geothermal energy and lithium supply and many EV companies have been signing agreements with geothermal lithium projects in Europe and North America.

There are a number of companies testing various DLE approaches. While their ideas differ, the concept remains the same: letting the brine flow through a lithium-bonding material using adsorption, ion-exchange, membrane-separation, or solvent-extraction processes, followed by a polishing solution to obtain lithium carbonate or lithium hydroxide. DLE technology is currently being considered not only by unconventional players but also by companies that traditionally develop “typical” brine assets, as DLE has several potential benefits. 

Evaporative processes common in South America are typically used to recover lithium from brines. The brine is pumped to the surface to evaporation ponds that are 5–10 km across, where it remains for around two years. DLE removes the need for an evaporation pond and the process takes 1–3 hours rather than years, at higher lithium recovery.

Image: Milennial Lithium

DLE is being tested at a pilot plant only 7 miles from the home of MEI in Falmouth, and I was pleased to be invited to see the operation by  Project Manager Richard Thompson, one of my former Camborne School of Mines students, who graduated in mineral processing in 1986.

Geocubed is a subsidiary company of Cornish Lithium and the pilot plant uses DLE ion-exchange technology to produce lithium chloride from geothermal waters. The intention is to extract heat from the geothermal waters to power local industries, as at the depth of the current borehole of 5.2 km the waters are at a temperature of 190C. Cornish Lithium will be drilling to more moderate depths, however, and the geothermal water will be returned once the heat and lithium have been extracted. No water will be lost, unlike in South America where water is lost in a water-scarce environment.

With Richard Thompson at the Geocubed pilot plant

The company’s pilot plant, which has received £2.9m of Government funding, has been built at its geothermal water test site at United Downs and is trialing a DLE technology provided by French firm GeoLith.

Richard said “The commissioned pilot plant has a pre-treatment process for the geothermal water, which includes filtering, pH adjustment and temperature control. Thereafter, the water is passed through the DLE Li-Capt process provided by GeoLith, where lithium is absorbed onto fine filaments, using a selective surface chemical. Once saturated, the filaments are desorbed using hydrochloric acid, rinsed and brought back into operation. The DLE absorption, desorption and rinsing is operated as a continuous process, in a series of vessels. The concentrated lithium chloride eluate will be stored for additional refining testwork, whilst the depleted brine is disposed of in an environmentally safe manner. The pilot plant has been designed to be as flexible as possible and is contained in standard containers, so that it can be located at different sites, as additional boreholes are trialed across Cornwall, for lithium recovery.”

The Geocubed team will test various DLE technologies at the plant throughout 2022, aiming to commercialise production within two years. The company is confident that the operations will not impact surface groundwaters due to the depths they are drilling, and that the reagents added to remove lithium will not be an environmental issue.  The company is working with relevant authorities to ensure they are complying with necessary environmental and safety requirements. From a process engineering perspective, Richard says the key challenges are ensuring the technology they pick can cope with other components of the groundwater, including silicates, and scaling the technology for higher throughput.

I really appreciate Richard's invitation and I will be following developments very closely over the next few year. Much is happening in Cornwall!

@barrywills