Highlights

• A life cycle assessment was conducted for 14 primary rare earth oxide supply chains across 12 mines in 9 countries.
• Heavy rare earth oxide (HREO) pathways are more environmentally intensive than light rare earths.
  • This is primarily due to reagent-heavy in-situ leaching processes, accounting for 72-83% of the total environmental burden.
• Chemical reagents are identified as the primary environmental hotspot across most impact categories.
• Energy inputs drive climate impacts, suggesting key areas for improvement include:
  • Reagent management
  • Recycling
  • Low-carbon power usage
• Global rare earth supply chains are largely dependent on Chinese refining and separation capacity.
  • Most non-China ore continues to be processed in Chinese facilities.
• This highlights Beijing's enduring midstream choke point despite upstream diversification efforts.

---

A new open-access life cycle assessment (LCA) led by Hongbin Wei at the Ganjiang Innovation Academy, Chinese Academy of Sciences (opens in a new tab) (with collaborators across China’s ionic rare earth and university labs) delivers the first “cradle-to-gate” comparison of 14 primary rare earth oxide (REO) supply chains spanning 12 mines in 9 countries—and it lands on a blunt conclusion: heavy rare earth oxide (HREO) pathways are systematically more environmentally intensive than light rare earth routes, largely because of reagent-heavy in-situ leaching, while the global supply chain still routes through Chinese refining/separation participation at scale, reinforcing Beijing’s effective midstream choke point.

What the researchers actually measured

This is a cradle-to-gate study: from digging/leaching ore → concentrating it → refining/separating into REOs, ending at the refinery gate (the “1 kg of REO” functional unit). It does not include magnet-making, product use, or recycling.

To compare apples-to-apples across countries, the team used the TRACI impact framework (a U.S. EPA–developed midpoint method) across 10 categories (e.g., global warming, acidification, eutrophication, human toxicity, resource depletion). They built inventories from peer-reviewed sources and public disclosures, but acknowledged data gaps in certain regions that required estimation using “similar mine” assumptions.

Key findings that matter to investors and policymakers

1. Heavy rare earth supply chains are “hotter” — and leaching drives it

Across HREO pathways, in-situ leaching dominates the total burden (reported ~72%–83%). The reason is not mysterious: ion-adsorption clays require large volumes of chemical solutions, extensive pumping, and multiple chemical steps to precipitate and purify the rare earths. In short: more chemicals, more handling, more waste streams.

2. Chemicals are the main hotspot; energy drives climate impacts

The study finds chemical reagents are the primary hotspot across most impact categories, while electricity and diesel strongly influence global warming potential and resource depletion. Translation: if you want cleaner rare earths, reagent management and recycling, plus lower-carbon power, are the biggest levers—not just incremental tweaks at the mine.

3. Ore grade and process maturity change the footprint dramatically

High-grade ore and modern flowsheets can materially reduce environmental burdens. The authors point to advanced routes (e.g., mature refining chains) as consistently lower-impact than low-grade, less-efficient routes that must process more rock (and therefore more chemicals and energy) per kilogram of REO.

4. Transport is usually small—until trucking and distance explode

On average, transport contributes a small share (reported roughly 0.04%–3.05%) of total impacts. But it becomes “non-negligible” where supply chains are trucking-intensive over long distances, which can meaningfully elevate toxicity-related indicators tied to fuel combustion and logistics intensity.

The uncomfortable midstream reality: “diversified mining,” centralized processing

Even as mining is slowly diversifying, the study’s supply-chain mapping underscores a hard truth: a large share of global routes still send concentrates to Chinese enterprises for refining/separation, meaning “non-China ore” often becomes “China-processed REO.” The paper explicitly frames most non-China pathways as China-linked at the processing stage, with only limited routes meaningfully independent at scale. This is the practical basis for today’s processing monopoly: not total mining control, but control of the separation/refining bottleneck where value—and leverage—concentrates.

Implications: what this means for the ex-China buildout

• Permitting and ESG reality-check: If Western governments want ex-China HREOs, they must confront that HREO production is often environmentally tougher, especially for ion-adsorption clays. Expect higher scrutiny around reagents, wastewater, and toxicity pathways, not just CO₂.
• Where subsidies should aim: The highest ROI policy levers are reagent recycling, process upgrades, and clean power, not simply “open more mines.”
• Traceability becomes industrial strategy: The study’s dataset logic supports a future where buyers demand auditable, pathway-level environmental labeling—which could penalize opaque supply chains and reward cleaner ones.

Limitations and controversial edges

Data uncertainty in opaque regions: The authors acknowledge limited access to plant-level data in parts of the world, requiring proxy estimates. That means some pathway rankings—especially where disclosures are thin—should be treated as directional, not absolute.

TRACI is U.S.-anchored: TRACI’s characterization factors are strongest for North American contexts; applying it globally can introduce methodological friction (the authors also reference cross-checking with another method in supplementary work).

Cradle-to-gate only: Excluding downstream manufacturing and can understate future improvement potential—especially as recycled REEs scale.

Institutional context: The work is led by Chinese institutions. That does not invalidate results, but readers should remain alert to what’s emphasized (process levers, governance) versus what’s outside scope (e.g., enforcement realities, informal production).

Closing: the signal beneath the numbers

This paper doesn’t just quantify footprints—it clarifies the strategic map. Heavy rare earths remain the hardest, dirtiest part of the chain, and the world’s “diversification story” often still ends at a Chinese separation plant. The path to resilience is not only new mines; it is new chemistry disciplines, new power inputs, and new midstream capacity built to modern environmental standards.

Citation: Wei H., Liu X., Zhao S., Li Q., Jiang W., Shi Z., Wu Y., Wang L. A life cycle assessment and comparative evaluation of global primary rare earth oxide supply chains. Ecological Indicators (Vol. 182, Article https://english.cas.cn/institutes/research_bodies/index_17893_10.shtml (opens in a new tab)), version of record online Jan 6, 2026. DOI:

10.1016/j.ecolind.2025.114575.