New Horizons in Lithium Sourcing & Extraction

October 31, 2024

Authors

Brun Hilbert, Jr., Ph.D., P.E.

Principal Engineer

Mechanical Engineering

Menlo Park

Julian Hallai, Ph.D., MBA, P.E., PMP

Managing Engineer

Mechanical Engineering

Houston

Commercial-scale direct lithium extraction technologies present big opportunities for the battery industry — with big challenges still ahead

Surging demand for and are key drivers of what some are calling — the global race to source and refine lithium to feed the world's growing appetite for lithium-ion batteries. According to , demand for lithium has tripled since 2017, and it's expected to increase tenfold by 2050, resulting in a likely shortage as soon as the 2030s.

Concerns over lithium's — including production processes that generate significant carbon dioxide emissions and consume staggering water resources — have many stakeholders considering new battery chemistries. However, with some of the most promising contenders (solid-state, silicon-anode, sodium-ion) still in development, and Li-ion batteries commercially established, alternative lithium sourcing practices that are more environmentally friendly are gaining traction, including direct lithium extraction (DLE) technology.

As U.S. regulatory momentum — led by the Biden Administration's Inflation Reduction Act — grows around securing and other critical minerals, the application of DLE to geothermal and oilfield brines across the U.S. could represent a significant shift from conventional lithium harvesting methods practiced in Australia, Chile, and China. For DLE to reach its full potential, however, manufacturers and other industry stakeholders will have to first overcome key regulatory, legal, financial, and technological challenges.

The potential benefits of DLE

While lithium has historically been produced through open-pit surface and underground rock mining techniques, today, almost is produced from brine evaporation ponds. This method involves drilling subsurface rock formations to reach brine aquifers, pumping brine into surface ponds, a lengthy water evaporation process, and filtering out concentrated lithium salts. It also requires approximately or more a year to extract a single ton of lithium.

DLE, on the other hand, does not involve evaporation ponds, rock mining, or the associated water waste and carbon emissions. One key advantage of DLE is that after pumping the brine to the surface, the water is subjected to direct extraction — by mechanical or electrochemical processes — after which any treatment water or unused brine is injected back into deep subsurface formations, well below useable sources of drinking water.

Applying DLE to domestic oil and gas wells and geothermal projects

The promise of DLE extends beyond lithium harvesting from dedicated brine production wells. The same DLE techniques can be used to extract lithium from the so-called "produced water" from oil and gas wells and the brine from geothermal energy generation, products otherwise considered industrial wastes.

Produced water — which contains hydrocarbons, salts, a variable mix of additives, and other solids and substances, including lithium — is fluid with gas and oil that, once extracted during normal production processes, is typically either injected back underground or recycled for future hydraulic fracturing operations, and which, with the application of DLE technology, represents a new resource for lithium sourcing. Shale in the Appalachian Basin, including Pennsylvania's — the largest reserve of natural gas in the U.S. — is particularly rich in lithium, with promising implications for domestic lithium production through DLE. A in the journal Scientific Reports estimated that produced water from the Marcellus Shale formation alone could satisfy 40% of current U.S. lithium consumption, and other regions like the , where large oil and gas companies have begun DLE projects, provide similar cause for optimism.

As part of additional efforts to boost domestic lithium production, the state of California is to extract battery-grade lithium-hydroxide during geothermal energy generation at the Salton Sea, in this case resourcing deep brine ponds (and their lithium salts) exposed in the course of drilling through fractured hard rock formations.

Challenges ahead for DLE implementation

Despite DLE's potential, battery manufacturers, multinational oil and gas operations, and other minerals and energy storage stakeholders face an array of challenges to fulfill the promise of this emergent technology.

Oil and gas field-produced saltwater and geothermal brines are potential lithium sources — but not very dense ones. Lithium concentrations can vary widely from field to field, even within a single location, and low lithium concentrations would reduce yield and ROI for DLE projects. Geochemical assessments and reservoir engineering can help support exploration, identify optimal sources, and accurately characterize the quality of reserves in petrochemical or geothermal fields.
Despite successful laboratory testing and promising small-scale experimentation, DLE processes — including the use of electromembranes, organic solvents, and nanofiltration — are not yet proven at scale in the field. DLE extraction opportunities will benefit from careful analysis and refinement that includes knowledge of chemicals, mechanical engineering, geology, materials chemistry, and other areas to improve the profitability and productivity of their processes in producing "battery-grade lithium," generally defined as 99-99.5% pure lithium carbonate or lithium hydroxide.
Specific petroleum production and geothermal field locations and conditions and battery manufacturing needs will require proper selection of DLE methodologies suited to such circumstances. Whether one of the approaches mentioned above or others like adsorption, selective precipitation, or thermal-assisted techniques, the selected DLE methodology should be informed by a deep understanding of site geology, lithium concentrations and quality, and current production processes.
DLE projects in oil and gas brines and geothermal deposits represent a new frontier for lithium sourcing — but also for commercial and industrial regulation. Oil and gas drilling and production is regulated in virtually all U.S. states, which includes state-regulated royalty structures that grant fees to those with mineral rights. In contrast, state regulation of brines, produced water, and lithium extraction is uneven.
Regulatory frameworks related to the extraction of other substances from brine may also prove useful in defining DLE royalites. For example, Arkansas has long regulated the extraction of bromine (for its fire-retardant properties) from brine, providing a legal structure that could be applied to lithium extraction, despite . In Texas, as in some other states with significant volumes of produced brine, royalty agreements are negotiated on a case-by-case basis in the absence of formalized regulations. DLE projects operating in states without established regulatory frameworks will want to thoroughly evaluate existing regulations and royalty structures to understand existing and potential responsibilities.
Some DLE methods pursued for their performance may require additional processes or evaluations to mitigate potential environmental issues. The use of solvent extractions, for instance, offers a high selectivity of lithium extraction (relative to sodium and magnesium ions) but may necessitate brine treatment after DLE to address the presence of kerosine and trioctylphosphine oxide or other extractants and residues. Thorough environmental risk assessments can support decision-making and regulatory compliance before extraction, during production and processing, and after brine re-injection.
While repurposing existing oil and gas field wells is cost efficient compared to drilling new wells for DLE, such wells are typically old and may be corroded or partially plugged. Field and well files should be carefully reviewed to secure key operational elements. This can include feasibility studies to assess well pressure and seal integrity before pumping brine from aquifers, as well as lease evaluations to understand any limitations on the use of existing wells.

Despite technological and regulatory uncertainty, DLE exploration and commercialization is moving rapidly.

The path toward secure and sustainable lithium sourcing

Despite technological and regulatory uncertainty, DLE exploration and commercialization is moving rapidly. Through its Smackover project and other DLE projects worldwide, ExxonMobil has set a goal to supply lithium for more than by 2030, and Standard Lithium's from the Department of Energy to construct a commercial-scale extraction and processing facility for battery-grade lithium carbonate represents an unprecedented boost to the modern, domestic production of critical minerals.

And yet, as the "white gold" rush turns to oil and gas brines and geothermal projects for more secure, sustainable lithium harvesting, commercially successful DLE applications will require continued innovation rooted in rigorous scientific analysis. Cutting-edge techniques, such as hydrogeological modeling of lithium brine deposits, and applied scientific and engineering expertise will help industry fulfill DLE's promise to reduce the resources required to source this key component of the world's energy future.

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