Geothermal Rare Earth Elements from Brines: Unlocking Critical Minerals, Lithium, and Strategic Metals from Clean Geothermal Energy
Geothermal brines can become a meaningful source of rare earth elements (REEs) and other critical minerals, but the industry is still in an early, pre‐commercial phase where technology, economics, and policy need to align.
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Why Geothermal Brines Matter for Critical Minerals
Geothermal systems circulate hot, mineral-rich fluids through crustal rocks, dissolving metals and concentrating them in brines that already flow through wells for power and heat. Unlike conventional mining, which moves huge volumes of rock, geothermal operations tap fluids that are already being pumped, monitored, and handled for energy production.
Several factors make geothermal brines attractive for critical minerals:
- They contain lithium, REEs, and other valuable metals at trace to moderate concentrations.
- Infrastructure (wells, pipelines, power plants) already exists at many sites.
- Co-production of minerals with baseload renewable energy lowers the carbon footprint of supply chains.
For countries expanding geothermal, such as Kenya and the broader East African Rift, this co‑production model could turn energy fields into strategic mineral hubs without opening new mines.
What’s in Geothermal Brines? Rare Earths and More
Geothermal brines vary widely by geology, depth, and temperature, but multiple studies show they carry a suite of critical elements at low to moderate concentrations.
Typical targets include:
- Rare earth elements (REEs), especially light REEs like La, Ce, Nd and sometimes heavier REEs.
- Lithium, often at tens to hundreds of mg/L in high‑salinity systems.
- Other critical metals such as gallium, germanium, cobalt, and sometimes precious metals.
A widely cited assessment of geothermal fields in the western United States found measurable REEs and other strategic metals in brines and steam, suggesting large aggregate resource potential if extraction becomes economic. European high‑enthalpy brines show similar patterns, with lithium, bromine, and various metals present at levels attractive enough to justify pilot projects.
The challenge is that these elements usually occur:
- In very dilute concentrations compared with ore-grade rock.
- Mixed with high levels of common ions (Na, Ca, Cl, SO₄) that can interfere with selective extraction.
Instead of “high grade deposits,” geothermal brines are better viewed as continuous, low‑grade flows, where value comes from volume and smart process design.
Current Extraction Technologies for REEs and Critical Minerals
Researchers and companies are testing several extraction pathways tailored to hot, complex geothermal fluids. [1][5][6][8] The main technology families are:
1. Sorbent and Adsorbent Materials
Solid sorbents that selectively bind metals from brine are one of the most promising routes.
- Advanced organic and inorganic sorbents have been developed to capture REEs and other metals from geothermal waters, showing high removal efficiencies even at trace concentrations.
- Nanostructured sorbents (e.g., functionalized silica, polymer resins, metal oxides) often outperform commercial resins because of high surface area and tailored binding sites.
Once metals are loaded onto the sorbent, they are stripped with an eluant (often an acid), and the sorbent is regenerated for multiple cycles, making continuous operation possible.
2. Magnetic Core–Shell Nanoparticles
A landmark study demonstrated REE extraction from geothermal brines using magnetic nanoparticles coated with selective functional layers.
Key features:
- Magnetic cores (usually iron oxides) allow rapid separation from brine using magnetic fields.
- Shell layers carry functional groups that selectively bind REEs over competing ions.
- Techno‑economic analysis shows that, under favorable brine compositions and REE prices, such systems can be cost‑competitive, though current economics remain challenging.
This approach is attractive because it reduces filtration complexity and enables compact reactor designs suitable for plant integration.
3. Hybrid Capacitive Deionization and Electrochemical Methods
Hybrid capacitive deionization processes apply electrical potentials to porous electrodes to adsorb ions selectively, including REEs. By tuning voltage and electrode chemistry, specific elements can be enriched from geothermal brines.
Electrochemical systems offer:
- Fine control over selectivity via potential and electrode materials.
- Lower chemical reagent requirements compared with some conventional processes.
- Modular installation potential alongside existing cooling and treatment units.
However, they must withstand high temperatures, scaling, and fouling typical of geothermal fluids.
4. Biological and Bio‑Inspired Extraction
Microbial cell surfaces and bio‑sorbents can selectively adsorb REEs from dilute solutions. Laboratory work using bacterial cell surface adsorption has shown promising REE recovery from geothermal-like fluids, suggesting potential low‑energy, environmentally benign processes.
Such systems remain largely experimental but could add value in niche settings or as polishing steps in multi‑stage flowsheets.
5. Conventional Solvent Extraction and Ion Exchange
Solvent extraction and ion‑exchange resins are standard in REE hydrometallurgy and can be adapted to geothermal contexts.
- Ion‑exchange resins can be placed in columns through which brine flows, capturing target ions.
- Solvent extraction can be applied to pre‑concentrated streams after partial desalination or sorbent‑based enrichment.
These mature technologies provide a baseline, but harsh geothermal chemistry and diluted metals make direct application difficult without pretreatment.
Techno‑Economic Feasibility: Is It Competitive?
Even the most sophisticated extraction process must overcome economic hurdles. Multiple techno‑economic and feasibility studies highlight both potential and constraints.
Cost Drivers
Main cost components include:
- Capital expenditures for extraction modules, sorbent regeneration systems, and integration with geothermal plants.
- Operating costs for sorbents, reagents, energy, and maintenance.
- Brine‑specific costs due to scaling, corrosion, and pre‑filtration.
In many analyses, the dominant uncertainty is the recoverable metal yield per unit of brine, which depends on site‑specific chemistry and process efficiency.
Revenue Streams and Co‑Production Value
Economic models frequently explore co‑production of electricity, heat, and minerals:
- Co‑produced lithium from geothermal brines can significantly improve project revenues and competitiveness versus standalone power generation.
- For REEs, the value is more complex because of variable prices, the need for separation of individual elements, and more intensive purification.
European studies on high‑enthalpy brines indicate that, under favorable market conditions and optimized designs, raw material extraction can substantially enhance the profitability of geothermal projects.
Key Findings from Techno‑Economic Studies
Several consistent conclusions emerge:
- Current economics for REE recovery from geothermal brines remain marginal, mainly due to low concentrations and complex chemistry.
- Novel nanofluid and sorbent technologies show significant promise in lowering costs and improving selectivity, but require scale‑up and long‑term testing.
- Direct lithium extraction is closer to commercial deployment than REEs, but the same platforms can be adapted to multi‑metal recovery in the future.
Projects like CHPM2030 in Europe and DOE‑funded studies in the United States have developed methodologies for assessing economic feasibility, combining resource characterization with process simulation and financial modeling.
Environmental and Social Advantages Over Conventional Mining
If geothermal mineral recovery becomes commercial, it could address several environmental and social challenges associated with traditional mining.
Benefits include:
- Lower surface footprint: Geothermal plants occupy relatively small areas compared with open‑pit mines.
- Reduced waste rock and tailings: Fluids are processed in closed systems, minimizing solid waste.
- Co‑generation with low‑carbon energy: REEs and lithium from geothermal brines would carry much lower embedded emissions per kilogram than those from many mining operations.
- Potential for local value creation: For regions already investing in geothermal (such as the Rift Valley), mineral co‑production can enhance energy security and industrial development simultaneously.
Challenges remain, including managing chemical reagents, ensuring reinjection of treated brines without ecosystem impacts, and maintaining transparency in benefit sharing with communities.
Future Markets and Strategic Role of Geothermal REEs
Global demand for rare earths and other critical minerals is accelerating due to clean energy technologies, electric vehicles, wind turbines, and advanced electronics. [5][9] Traditional supply chains are heavily concentrated in a few countries, raising concerns about security of supply and geopolitical risk.
Geothermal‑derived REEs and critical minerals could play several strategic roles:
- Diversification: Even modest volumes can help diversify away from single‑country dominance in REE refining and supply.
- Green branding: Minerals co‑produced with geothermal energy can command a premium in markets where carbon and environmental footprints matter, such as EVs and high‑end electronics.
- Regional development: Geothermal fields in East Africa, the US, Europe, and Asia could anchor integrated “energy‑plus‑materials” clusters, combining power generation, mineral processing, and possibly magnet and battery manufacturing.
However, geothermal will likely be a supplementary source rather than a complete replacement for mining. Its competitive niche will be:
- High‑value critical elements where even small volumes are significant.
- Markets that reward low‑carbon, responsible production.
- Sites where existing geothermal operations can add mineral recovery with limited new capital.
Main Obstacles and Research Priorities
To move from pilot projects to commercial deployment, several obstacles must be overcome.
Key technical challenges:
- Improving selectivity and capacity of sorbents and nanoparticles in real brines with many competing ions.
- Ensuring long‑term stability and regeneration of sorbents under high temperature and corrosive conditions. [1][8]
- Managing scaling, fouling, and corrosion in extraction equipment.
- Integrating extraction modules into plant layouts without compromising power output.
Economic and market priorities:
- Reducing capital and operating costs through modular, standardized systems.
- Developing robust techno‑economic models that account for dynamic metal prices and multi‑metal recovery.
- Creating policy and financial incentives for co‑produced low‑carbon minerals.
Regulatory and social aspects:
- Establishing clear permitting and environmental standards for mineral recovery from geothermal operations.
- Ensuring fair value distribution to host communities and countries, especially where geothermal development is part of broader industrialization strategies.
Ongoing DOE‑funded research in the US and European initiatives such as CHPM2030 are actively addressing these gaps, with a focus on flexible, scalable technologies and comprehensive feasibility frameworks.
Outlook: Can Geothermal Brines Become a Serious Source of Critical Minerals?
Based on current research, geothermal brines are unlikely to replace conventional REE and critical mineral mining, but they can evolve into an important supplementary, low‑carbon source over the next decade.
What seems most likely is:
- Early commercial projects centered on lithium, where economics are already promising.
- Progressive integration of REE and other critical mineral recovery as sorbent, nanoparticle, and electrochemical technologies mature. [6][8][10]
- Geographic “hot spots” where brine chemistry, geothermal scale, and policy support align, creating flagship projects that prove the concept and drive replication.
For regions like Kenya and the broader East African Rift, watching and participating in this trend can unlock new strategic value: not only clean baseload power, but also a small yet high‑impact stream of critical minerals feeding local and global clean‑energy industries.
In short, geothermal brines will not single‑handedly solve global REE and critical mineral shortages, but they are poised to become a high‑value, low‑footprint piece of a more resilient and sustainable resource puzzle.
Geothermal brines can become a meaningful, low‑carbon source of rare earth elements (REEs) and other critical minerals, but the opportunity is still early‑stage and highly site‑specific. The most realistic scenario is that geothermal will supplement, not replace, conventional mining—especially for high‑value, lower‑volume critical elements and in markets that reward “green” supply chains.
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