| Author(s) |
Debora Berti, John G. Groppo, Prakash Joshi, Dorin V. Preda, David P. Gamliel, Todd Beers, Michael Schrock, Shelly D. Hopps, Tonya D. Morgan, Bernd Zechmann, Anne E. Oberlink, James C. Hower |
| Abstract Scope |
Fly ash from an eastern Kentucky high-volatile bituminous coal blend was beneficiated (<75 μm) to reduce carbon and spinels, then reacted with strong acid in a pilot-scale unit to extract rare earth elements (REE) and other critical elements. Polished epoxy-bound pellets of the beneficiated and leached ashes were analyzed by SEM, EDS, TEM, and EELS. Bulk chemistry of the feed, beneficiated, and leached ashes shows similar UCC–normalized REE patterns and depletion of major oxides (except SiO₂), REE, V, Cr, Mn, Ni, As, Rb, Sr, Zr, Ba, and Pb in the processed ash. REE-bearing phases identified by SEM-TEM-EDS include zircon with Y (± Ce, Nd, Gd,); baddeleyite (ZrO2), fergusonite (YNbO4), yttriaite (Y2O3), xenotime (YPO4); and monazite with light REE, Gd, Dy, Er, and Th. Certain glassy fly ash spheres showed 2- to 4-μm amorphous rims enriched in Si but depleted in other elements, including REE, likely dissolved during leaching. |