Process evaluation and flowsheet development for the recovery of rare earth elements from coal and associated byproducts

R. Q. Honaker, J. Groppo, R. H. Yoon, G. H. Luttrell, A. Noble, J. Herbst

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


Coal and coal byproducts produced annually contain a sufficient amount of rare earth elements (REEs) to meet current U.S. demand. The REEs exist in the form of minerals, ion-adsorbed elements associated with clays, and chemically bonded elements within the organic coal matrix or host mineral. Researchers at three universities collaborated to evaluate the effectiveness of existing physical and chemical concentration processes for the recovery of the REEs. The efforts found that physical separation processes can increase the total REE content in the thickener underflow material collected from a Central Appalachian coal cleaning facility from around 300 ppm to values greater than 17, 500 ppm on an ash basis. Leaching followed by solvent extraction was found to be the most effective to recover the REEs from coarse middlings materials collected from multiple coal basins, as indicated by recovery values exceeding 80 percent. Based on material characterization data and process evaluations conducted for several potential feed coal sources, economic recovery of the REEs will require byproduct production of both clean coal and REE concentrate using a process flowsheet that is unique for each source.

Original languageEnglish
Pages (from-to)107-115
Number of pages9
JournalMinerals and Metallurgical Processing
Issue number3
StatePublished - Aug 2017

Bibliographical note

Funding Information:
This material is based upon work supported by the Department of Energy under Award Number DE-FE0027035. The authors are greatly appreciative of the contributions provided by Dr. James Hower, Dr. Cortland Eble and Mr. Jason Backus. The completion of the experimental work would not have been possible without the efforts of several graduate research associates, including Mr. Wencai Zhang, Ms, Xinbo Yang and Mr. Alind Chandra


  • Coal
  • Flowsheet
  • Process evaluation
  • Rare earth elements

ASJC Scopus subject areas

  • Control and Systems Engineering
  • General Chemistry
  • Geotechnical Engineering and Engineering Geology
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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