Geochemistry of carbon nanotube assemblages in coal fire soot, Ruth Mullins fire, Perry County, Kentucky

Coal fires typically generate a variety of mineral and organic deposits associated with the venting emission gases. In addition to the tars typically found at the Ruth Mullins coal fire, Perry County, Kentucky, a sooty carbon, superficially similar to a carbon from a university-based stoker-fired power plant, was sampled in an August 2010 visit. Carbons in the soot include complex carbon particles, nanotubes encapsulating Hg, onion-like structures with polyhedral and quasi-spherical morphology with hollow centers, and metal-bearing multiwalled nanotubes. Mineral and amorphous inorganic phases included glassy Al-Si spheres with associated Pb and Se; nanopyrite grains with trace As and Se; nanohematite with V3+; salammoniac; quartz; Cr- and Pb-bearing jarosite; fibrous pickeringite with surficial natrojarosite; and Cd-, Co-, Mo-, Ni, V-, W-, and Zr-bearing nanospheres. The enrichment of N-15 in the soot is associated with the fractionation of NH3 to NH4 in the formation of salammoniac. Selenium, Pb, and Zn are found in relatively high concentrations in the soot and Hg, with 5.68 ppm, has a higher concentration than any Kentucky fly ash. (C) 2011 Elsevier B.V. All rights reserved.