highlights
- Ion adsorbed rare earth (IARE) ores are the world’s main source of heavy rare earths such as dysprosium and terbium, but current in-situ leaching methods require large ammonium inputs, slow extraction, and risk slope instability and contamination.
- A critical review of 342 publications shows that the field is pivoting from pipe-end cleanup to source-level control: preventing impurity migration, improving ore permeability, reducing clay swelling, and reducing chemical dependence during the leaching stage.
- The security of future HREE supplies will depend on mastering cleaner, faster and safer extraction chemistries and geotechnical stability, and moving promising laboratory-scale innovations into validated field deployments with standardized metrics and scalable systems.
Ion adsorbed rare earth (IARE) ores are the world’s most important source of heavy rare earth elements (HREEs), the dysprosium and terbium class materials that keep high-performance magnets stable at high temperatures. In a new critical review in the Journal of Rare Earths, Bingxuan He and colleagues Central South University, Department of Mineral Processing and Biotechnology (Opens in new tab);The Department of Education’s Key Laboratory of Biohydrometallurgy is investigating why extracting HREE from these ores is both strategically essential and technically robust. Their core message is clear to the Rare Earth Exchanges™ community. In summary, while IARE ores can efficiently produce HREEs because many rare earths are retained in clay, current in-situ leaching methods still come with significant costs (high ammonium inputs, slow leaching rates, poor impurity control, and even unstable slopes), so the next generation of extraction must be greener, faster, and safer without sacrificing recovery.
REEx reflection
A research team from Central South University in Changsha, Hunan province, explains how the world extracts heavy rare earth elements such as dysprosium and terbium from the ion-adsorbing clay deposits that make up the bulk of the world’s supplies. These ores are easier to process than hard rock deposits because the rare earths exist loosely on the surface of the clay, but current methods use large amounts of ammonium chemicals, are time-consuming, and can cause soil instability and contamination. The study reviews more than a decade of research and highlights new ideas to reduce chemical use, manage impurities early in the process, improve the way fluids move through the ore, and prevent clay swelling. The authors conclude that future advances will depend on cleaner chemistry and safer in-situ leaching methods to make heavy rare earth production more efficient, stable, and environmentally friendly.
Research methods: From mineralogy to mechanics
This is a critical review that synthesizes the research trajectory and technical bottlenecks in this field, based on 342 publications since 2010 identified by a Web of Science keyword search (“ion-adsorbed rare earth ores” + “leaching”). Starting ‘from the ground up’, the authors consider the evolution of mineral properties, rare earth occurrences (most are ion-exchangeable, while colloidal and mineral-bound species are less studied), and mining/extraction approaches. Next, we organize the technological advances in five innovation directions for in-situ leaching agents.
- reduced ammonium salt input, 2) reduced leaching of impurities, 3) improved recovery of non-ionic rare earth states, 4) improved permeability/permeability, and 5) reduced clay swelling. They will also explore “non-mainstream” options such as bioleaching and field-enhanced leaching (e.g. electromagnetic/ultrasound assisted).
Key findings: Areas shifting upstream
This review documents a visible shift from pure “end-of-life treatment” (cleaning of impurities after leaching) to source-level controls that prevent the migration of aluminum/iron and other impurities in the first place and improve solution flow through the orebody. The authors note that over the past five years, research emphasis has shifted from kinetics and leaching efficiency to permeability, clay expansion control, and ore microstructure, reflecting the recognition that in situ leaching is as much a hydrogeotechnical problem as it is a chemical one. The authors argue that sustainable progress depends on smarter pairing liquid chemistry (Opens in new tab) Stability management reduces irreversible changes to soil structure and shear strength during injection.
Restrictions and controversial edges
As this is a review, no new field studies are introduced in this paper. Many promising approaches remain at laboratory scale or early pilot concepts, and actual deployment is subject to economics, site variability, and regulatory constraints. Practical tensions still remain. IARE ore represents a large proportion of HREE reserves, but the main mining routes that inject chemicals into the orebody can cause permanent geotechnical and environmental disturbances, making “green, sustainable and efficient” not a slogan but a demanding three-pronged goal.
Implication: The next magnet war could be won with leech chemistry
for rare earth exchange Dear reader, this paper highlights the reality of supply chains. HREE security is not just about owning ore deposits, it’s about mastering extraction and management in ore bodies. If industry can reduce its dependence on ammonium, reduce impurity migration, and stabilize ore permeability and slope, both costs and social licenses could be improved. What follows is more field-validated demonstrations, standardized metrics for impurity control and stability, and a clearer path to scaling “novel” methods beyond the laboratory. The frontier is not just about new mines. It’s a better infusion system.
Quote: He, B., Wang, J., Liu, Y., Zhang, R., Liu, H., Yang, B., Zhu, Z., Hu, S., and Qiu, G. (2026). Mechanisms of rare earth element extraction from ion adsorption rare earth ores: A critical review. rare earth journal (in press). https://doi.org/10.1016/j.jre.2026.01.032 (Opens in new tab)