Nano-Scale Rare Earth Distribution in Fly Ash Derived from the Combustion of the Fire Clay Coal, Kentucky

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.

[1]  S. Dai,et al.  Rare earth elements and yttrium in coal ash from the Luzhou power plant in Sichuan, Southwest China: Concentration, characterization and optimized extraction , 2019, International Journal of Coal Geology.

[2]  J. Hower,et al.  Differences in bulk and microscale yttrium speciation in coal combustion fly ash. , 2018, Environmental science. Processes & impacts.

[3]  R. Honaker,et al.  Rare earth elements recovery using staged precipitation from a leachate generated from coarse coal refuse , 2018, International Journal of Coal Geology.

[4]  C. Ward,et al.  Modes of occurrence of non-mineral inorganic elements in lignites from the Mile Basin, Yunnan Province, China , 2018 .

[5]  M. Turk,et al.  Rare earth elements in superhigh-organic-sulfur Raša coal ash (Croatia) , 2018, International Journal of Coal Geology.

[6]  J. Hower,et al.  Rare earth minerals in a “no tonstein” section of the Dean (Fire Clay) coal, Knox County, Kentucky , 2018, International Journal of Coal Geology.

[7]  Ronghong Lin,et al.  Evaluation of trace elements in U.S. coals using the USGS COALQUAL database version 3.0. Part I: Rare earth elements and yttrium (REY) , 2018 .

[8]  R. Addleman,et al.  Leaching behavior of rare earth elements in Fort Union lignite coals of North America , 2018 .

[9]  S. Dai,et al.  Determination of Eu concentrations in coal, fly ash and sedimentary rocks using a cation exchange resin and inductively coupled plasma mass spectrometry (ICP-MS) , 2018 .

[10]  J. Hower,et al.  Rare earth element associations in the Kentucky State University stoker ash , 2018 .

[11]  James C. Hower,et al.  Distribution of rare earth elements in coal combustion fly ash, determined by SHRIMP-RG ion microprobe , 2017 .

[12]  C. Ward,et al.  Anomalies of rare metals in Lopingian super-high-organic-sulfur coals from the Yishan Coalfield, Guangxi, China , 2017 .

[13]  Ronghong Lin,et al.  Enrichment of rare earth elements from coal and coal by-products by physical separations , 2017 .

[14]  R. Finkelman,et al.  Coal as a promising source of critical elements: Progress and future prospects , 2017 .

[15]  J. Hower,et al.  Size-Dependent Variations in Fly Ash Trace Element Chemistry: Examples from a Kentucky Power Plant and with Emphasis on Rare Earth Elements , 2017 .

[16]  Ross K Taggart,et al.  Trends in the Rare Earth Element Content of U.S.-Based Coal Combustion Fly Ashes. , 2016, Environmental science & technology.

[17]  J. Hower,et al.  Distribution of rare earth elements in eastern Kentucky coals: Indicators of multiple modes of enrichment? , 2016 .

[18]  C. Ward,et al.  A review of anomalous rare earth elements and yttrium in coal , 2016 .

[19]  James C. Hower,et al.  Notes on Contributions to the Science of Rare Earth Element Enrichment in Coal and Coal Combustion Byproducts , 2016 .

[20]  J. Hower,et al.  Notes on the Potential for the Concentration of Rare Earth Elements and Yttrium in Coal Combustion Fly Ash , 2015 .

[21]  Wojciech Franus,et al.  Coal fly ash as a resource for rare earth elements , 2015, Environmental Science and Pollution Research.

[22]  Robert S Blissett,et al.  An investigation into six coal fly ashes from the United Kingdom and Poland to evaluate rare earth element content , 2014 .

[23]  J. Hower,et al.  Petrology, Mineralogy, and Chemistry of Size-Fractioned Fly Ash from the Jungar Power Plant, Inner Mongolia, China, with Emphasis on the Distribution of Rare Earth Elements , 2014 .

[24]  C. Ward,et al.  Mineralogical and geochemical compositions of the coal in the Guanbanwusu Mine, Inner Mongolia, China: Further evidence for the existence of an Al (Ga and REE) ore deposit in the Jungar Coalfield , 2012 .

[25]  Robert B. Finkelman,et al.  Geochemistry of trace elements in Chinese coals: A review of abundances, genetic types, impacts on human health, and industrial utilization , 2012 .

[26]  V. V. Seredin,et al.  Coal deposits as potential alternative sources for lanthanides and yttrium , 2012 .

[27]  S. Dai,et al.  Abundances and distribution of minerals and elements in high-alumina coal fly ash from the Jungar Power Plant, Inner Mongolia, China , 2010 .

[28]  S. Dai,et al.  Mineralogy and geochemistry of boehmite-rich coals: New insights from the Haerwusu Surface Mine, Jungar Coalfield, Inner Mongolia, China , 2008 .

[29]  James C. Hower,et al.  Impact of coal properties on coal combustion by-product quality: examples from a Kentucky power plant , 2004 .

[30]  J. Hower,et al.  Geochemistry of the Pond Creek coal bed, Eastern Kentucky coalfield , 1989 .

[31]  Y. Hikichi,et al.  Melting Temperatures of Monazite and Xenotime , 1987 .

[32]  J. Hower,et al.  Cryptic sediment-hosted critical element mineralization from eastern Yunnan Province, southwestern China: Mineralogy, geochemistry, relationship to Emeishan alkaline magmatism and possible origin , 2017 .

[33]  J. Hower,et al.  Enrichment of U-Re-V-Cr-Se and rare earth elements in the Late Permian coals of the Moxinpo Coalfield, Chongqing, China: Genetic implications from geochemical and mineralogical data , 2017 .

[34]  J. Hower,et al.  Ponded and Landfilled Fly Ash as a Source of Rare Earth Elements from a Kentucky Power Plant , 2017 .

[35]  J. Hower,et al.  Rare Earth Element Distribution in Fly Ash Derived from the Fire Clay Coal, Kentucky , 2017 .

[36]  J. Hower,et al.  A Note on the Occurrence of Yttrium and Rare Earth Elements in Coal Combustion Products , 2013 .

[37]  S. Siew.  Scanning electron microscopy of human heart valves , 1985 .