Nano-scale rare earth distribution in fly ash derived from the combustion of the fire clay coal, kentucky

James C. Hower, Dali Qian, Nicolas J. Briot, Eduardo Santillan-Jimenez, Madison M. Hood, Ross K. Taggart, Heileen Hsu-Kim

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Fly ash from the combustion of eastern Kentucky Fire Clay coal in a southeastern United States pulverized-coal power plant was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). TEM combined with elemental analysis via energy dispersive X-ray spectroscopy (EDS) showed that rare earth elements (REE; specifically, La, Ce, Nd, Pr, and Sm) were distributed within glassy particles. In certain cases, the REE were accompanied by phosphorous, suggesting a monazite or similar mineral form. However, the electron diffraction patterns of apparent phosphate minerals were not definitive, and P-lean regions of the glass consisted of amorphous phases. Therefore, the distribution of the REE in the fly ash seemed to be in the form of TEM-visible nano-scale crystalline minerals, with additional distributions corresponding to overlapping ultra-fine minerals and even true atomic dispersion within the fly ash glass.

Original languageEnglish
Article number206
Issue number4
StatePublished - Apr 2019

Bibliographical note

Funding Information:
Funding: This work was funded by the National Science Foundation grants CBET-1510965 and CBET-1510861 to Duke University and the University of Kentucky, respectively. Access to characterization instruments and staff assistance was provided by the Electron Microscopy Center at the University of Kentucky, supported in part by the National Science Foundation/EPSCoR Award No. 1355438 and by the Commonwealth of Kentucky.

Publisher Copyright:
© 2019 by the authors. Licensee MDPI, Basel, Switzerland.


  • Coal combustion products
  • Lanthanides
  • Monazite

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Geology


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