Heavy Rare Earth Elements Review Identifies 13 Research Priorities for Sustainable Supply

Highlights

• Ion-adsorption deposits supply over 90% of global heavy rare earths, making their sustainable extraction a top strategic priority.
• Conventional ammonium-salt leaching poses serious environmental risks; alternatives like bioleaching and electrokinetic mining remain in early development.
• Future competitive advantage will belong to nations controlling the full value chain—from extraction and separation to magnet fabrication and environmental expertise.
• The review synthesizes a decade of research into 13 priority areas, covering deposit formation, mining evolution, environmental impacts, and remediation technologies.
• Outside China, commercial supplies of dysprosium, terbium, and yttrium remain critically limited, making processing technology as valuable as new discoveries.

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A comprehensive review (opens in a new tab) earlier this year led by Yilin He and colleagues, published in the Journal of Rare Earths, synthesizes the latest scientific understanding of heavy rare earth elements (HREEs)—the critical materials that enable electric vehicles, wind turbines, precision-guided weapons, robotics, and advanced electronics. Drawing together research from multiple Chinese universities and research institutes, the authors examine how ion-adsorption deposits form, how they are mined, the environmental consequences of extraction, and emerging remediation technologies. Rather than introducing new experimental data, the review distills a decade of rapidly expanding research into 13 priority areas for future investigation. Its central conclusion is clear: ensuring long-term heavy rare earth supply will require cleaner extraction technologies, stronger environmental stewardship, and continued scientific innovation—not simply opening more mines.

REEx Insight

This review reinforces one of Rare Earth Exchanges® core observations: the world's rare earth challenge is no longer geological—it is industrial. Finding additional deposits matters, but the competitive advantage increasingly belongs to those capable of extracting, separating, refining, and manufacturing heavy rare earth products while meeting increasingly stringent environmental standards.

The paper also implicitly reinforces another REEx theme. Heavy rare earths remain the most strategically constrained segment of the global supply chain. Outside China, commercial supplies of dysprosium, terbium, yttrium, and other heavy rare earth products remain limited, making environmentally responsible processing technologies as strategically valuable as new discoveries themselves.

In the Great Powers Era 2.0, industrial capability—not simply mineral ownership—will determine geopolitical leverage.

Small Elements, Outsized Importance

Heavy rare earth elements—including dysprosium (Dy), terbium (Tb), yttrium (Y), holmium (Ho), erbium (Er), and lutetium (Lu)—represent only a small fraction of total rare earth production, yet they enable many of today's highest-performance technologies.

By improving the high-temperature performance of permanent magnets, they are indispensable for:

• Electric vehicle traction motors
• Offshore wind turbines
• Missile guidance systems
• Military aircraft
• Robotics
• Medical imaging
• Advanced electronics

The review notes that ion-adsorption deposits currently provide more than 90% of global heavy rare earth supply, underscoring why these clay-hosted deposits occupy such an important place in strategic mineral policy.

Looking Across an Entire Industry

Rather than conducting laboratory experiments, the authors performed a comprehensive scientific review covering four interconnected areas:

• Formation of ion-adsorption deposits
• Evolution of mining technologies
• Environmental and human impacts
• Remediation of contaminated soil and water

The paper concludes by identifying 13 research priorities aimed at improving resource security while reducing environmental impacts.

Where the Industry Must Go Next

Several themes emerge consistently.

First, economically recoverable heavy rare earth resources remain scarce despite rapidly growing demand.

Second, conventional ammonium-salt in-situ leaching, while commercially successful, continues to pose significant environmental risks, including groundwater contamination and ecosystem degradation.

Third, promising alternatives—including electrokinetic mining, bioleaching, and improved remediation technologies—show considerable potential but remain largely in the research or early development stage rather than broad commercial deployment.

Keeping the Findings in Perspective

This is an authoritative review, but it is not a new field study.

The paper does not validate specific mining technologies at commercial scale, establish new economic models, or forecast future production. It also focuses primarily on China's ion-adsorption clay deposits, meaning some conclusions may not translate directly to hard-rock, carbonatite, or alkaline rare earth projects elsewhere in the world.

Investor Bottom Line

The most important message from this review is not that heavy rare earths are indispensable—that has long been established. The more significant conclusion is that future competitive advantage will increasingly belong to producers capable of combining secure supply with environmentally responsible extraction and processing. Rare Earth Exchanges would take that one step further: in the

Great Powers Era 2.0, the ultimate winners will not simply own heavy rare earth deposits—they will control the technologies, separation facilities, metal production, alloy manufacturing, magnet fabrication, and environmental expertise that transform those deposits into strategic industrial capability.

REEx Connect

Author	Role	Institution(s)
Yilin He †	Lead Author; Equal Contribution	State Key Laboratory of Deep Earth Processes and Resources, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (CAS); Guangdong Research Center for Strategic Metals and Green Utilization; Guangdong Provincial Key Laboratory of Mineral Physics and Materials; University of Chinese Academy of Sciences (UCAS), Beijing
Yongjin Xu †	Co-Lead Author; Equal Contribution	School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences (UCAS), Hangzhou
Gaofeng Wang	Co-Author	State Key Laboratory of Deep Earth Processes and Resources, Guangzhou Institute of Geochemistry, CAS; Guangdong Research Center for Strategic Metals and Green Utilization; Guangdong Provincial Key Laboratory of Mineral Physics and Materials; UCAS, Beijing
Yongqiang Yang	Co-Author	State Key Laboratory of Deep Earth Processes and Resources, Guangzhou Institute of Geochemistry, CAS; Guangdong Research Center for Strategic Metals and Green Utilization; Guangdong Provincial Key Laboratory of Mineral Physics and Materials; UCAS, Beijing
Lin Zhou	Co-Author	State Key Laboratory of Deep Earth Processes and Resources, Guangzhou Institute of Geochemistry, CAS; Guangdong Research Center for Strategic Metals and Green Utilization; Guangdong Provincial Key Laboratory of Mineral Physics and Materials; UCAS, Beijing
Jie Xu	Co-Author	School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences (UCAS), Hangzhou
Zhenyue Zhang	Co-Author	School of Resources & Safety Engineering, Wuhan Institute of Technology, Wuhan, China
Hongbo Zhao	Co-Author	School of Minerals Processing and Bioengineering, Central South University, Changsha; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha
Jingming Wei	Co-Author	State Key Laboratory of Deep Earth Processes and Resources, Guangzhou Institute of Geochemistry, CAS; Guangdong Research Center for Strategic Metals and Green Utilization; Guangdong Provincial Key Laboratory of Mineral Physics and Materials; UCAS, Beijing
Ru'an Chi	Co-Author	School of Resources & Safety Engineering, Wuhan Institute of Technology, Wuhan, China
Guanzhou Qiu	Co-Author	School of Minerals Processing and Bioengineering, Central South University, Changsha; Key Laboratory of Biohydrometallurgy, Ministry of Education, Changsha
Jianxi Zhu	Senior Author / Corresponding Research Lead	State Key Laboratory of Deep Earth Processes and Resources, Guangzhou Institute of Geochemistry, CAS; Guangdong Research Center for Strategic Metals and Green Utilization; Guangdong Provincial Key Laboratory of Mineral Physics and Materials; University of Chinese Academy of Sciences (UCAS), Beijing

Notes:

• † indicates equal contribution as co-first authors.
• The paper represents a collaboration among four major Chinese research centers:
• Guangzhou Institute of Geochemistry, Chinese Academy of Sciences (CAS) – Lead institution
• University of Chinese Academy of Sciences (UCAS) – Beijing and Hangzhou campuses
• Wuhan Institute of Technology
• Central South University, including the Key Laboratory of Biohydrometallurgy, Ministry of Education

This multidisciplinary team combines expertise in geochemistry, mineral exploration, strategic metals, environmental science, mineral processing, biohydrometallurgy, and sustainable mining, reflecting the paper's comprehensive focus on the entire heavy rare earth value chain—from ore genesis through extraction, environmental management, and remediation.

Citation: He Y, Xu Y, Wang G, et al. Heavy Rare Earth Elements: Critical Resources, Environmental Challenges and Pathways to Sustainability. Journal of Rare Earths. Published online January 14, 2026. DOI: 10.1016/j.jre.2026.01.016.