Highlights

• Comprehensive analysis of 29,152 peer-reviewed articles reveals growing research interest in extracting rare earth elements from coal and coal by-products.
• China leads global research output.
• Emerging opportunities for secondary rare earth element (REE) supply through coal ash processing and innovative extraction methods.
• Strategic potential for countries with legacy coal assets to transform environmental waste into critical mineral feedstock for emerging technologies.

---

Alarge-scale bibliometric study led by Temitope Love Baiyegunhi, MSc, PhD, and François Mulenga, PhD (Department of Mining Engineering, University of South Africa) catalogs how the world has studied rare earth elements (REEs) in coal and coal by-products from 2010–2024—and where the investable opportunities and blind spots may lie. Published in Petroleum and Coal (Pet Coal), the open-access review analyzes 29,152 peer-reviewed articles across 2,584 journals to track research themes, leading institutions, collaboration networks, and emerging methods.

Key Findings (Fast)

• Exploding interest: Publications rose steadily over 2010–2024, with average 21.5 citations/article and strong international co-authorship.
• Top themes: (1) Mode of occurrence of REEs in coal/ashes; (2) Sources & distribution; (3) Leaching as the primary recovery route.
• Rising methods & “white space”: Future work flagged in magnetic separation, CO₂ sequestration links, kinetics, pore structure, and numerical simulation—areas with commercial upside for process design.
• Leaders: China dominates output and citations, followed by the U.S. and Australia. Top hubs include China University of Mining & Technology; top journals include Fuel, Energy & Fuels, and International Journal of Coal Geology.
• Application pull: Keyword momentum around fly ash/bottom ash, geopolymer, gasification/pyrolysis, and CO₂ capture signals convergence with decarbonization and circular-materials markets.

Why It Matters (Implications for Investors/Policy)

• Secondary supply option: Coal ash and by-products can host REE concentrations comparable to some conventional ores, offering a waste-to-value pathway that could diversify supply outside of China’s minehead.
• Faster to pilot (maybe): Leveraging existing power-plant waste streams could reduce greenfield mine risk if selective leaching plus separation flowsheets scale economically.
• Strategic fit (U.S., India, South Africa): Countries with legacy coal assets could convert environmental liabilities to strategic REE feedstock, supporting magnet metals (NdPr/Dy/Tb) for EVs, wind, and defense.

What’s Missing (Limitations & Caveats)

• Bibliometrics does not equal feasibility: The study counts and maps papers; it does not validate grades, impurities, recoveries, capex/opex, or LCA outcomes.
• Data scope bias: Web of Science only, English-language articles only—useful for quality control but potentially excludes relevant non-WoS or non-English work.
• Process realism: Leaching dominates the literature, yet techno-economics, scale-up, reagent recycling, residue handling, and permitting are under-represented.
• Feed variability: Coal/ash chemistry varies by basin and burn conditions; “one-size flowsheet” risk remains high.

REEx Bottom Line

This is a map, not a mine plan—but a valuable one. For developers: focus on selective leaching + magnetic/ion-exchange separation, reagent recovery, and LCA-positive pilots tied to specific ash inventories. For policymakers, key areas to focus on include target pilot-to-demo funding, standards for ash characterization, and clear rules for residue stewardship. For investors, diligence should focus on site-specific assays, locked-cycle results, and unit-cost/LCA math, rather than publication counts.

Citation: Baiyegunhi TL*, Mulenga F. “Mapping the Global Research Trends on Rare Earth Elements in Coal and Coal Byproducts from 2010–2024 Using a Bibliometric Approach.” Petroleum and Coal 67(2): 647–665 (2025).

©!-- /wp:paragraph -->