title: Geochemistry of ultra-fine and nano-compounds in coal gasification ashes: a synoptic view.
abstract: The nano-mineralogy, petrology, and chemistry of coal gasification products have not been studied as extensively as the products of the more widely used pulverized-coal combustion. The solid residues from the gasification of a low- to medium-sulfur, inertinite-rich, volatile A bituminous coal, and a high sulfur, vitrinite-rich, volatile C bituminous coal were investigated. Multifaceted chemical characterization by XRD, Raman spectroscopy, petrology, FE-SEM/EDS, and HR-TEM/SEAD/FFT/EDS provided an in-depth understanding of coal gasification ash-forming processes. The petrology of the residues generally reflected the rank and maceral composition of the feed coals, with the higher rank, high-inertinite coal having anisotropic carbons and inertinite in the residue, and the lower rank coal-derived residue containing isotropic carbons. The feed coal chemistry determines the mineralogy of the non-glass, non-carbon portions of the residues, with the proportions of CaCO₃ versus Al₂O₃ determining the tendency towards the neoformation of anorthite versus mullite, respectively. Electron beam studies showed the presence of a number of potentially hazardous elements in nanoparticles. Some of the neoformed ultra-fine/nano-minerals found in the coal ashes are the same as those commonly associated with oxidation/transformation of sulfides and sulfates.
authors.affiliation: Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração, Victor Barreto, 2288 Centro, 92010-000 Canoas, RS, Brazil.
authors.forename: Marcio A
authors.initials: MA
authors.lastname: Kronbauer
authors.forename: Maria
authors.initials: M
authors.lastname: Izquierdo
authors.forename: Shifeng
authors.initials: S
authors.lastname: Dai
authors.forename: Frans B
authors.initials: FB
authors.lastname: Waanders
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Wagner
authors.forename: Maria
authors.initials: M
authors.lastname: Mastalerz
authors.forename: James C
authors.initials: JC
authors.lastname: Hower
authors.forename: Marcos L S
authors.initials: ML
authors.lastname: Oliveira
authors.forename: Silvio R
authors.initials: SR
authors.lastname: Taffarel
authors.forename: Delmar
authors.initials: D
authors.lastname: Bizani
authors.forename: Luis F O
authors.initials: LF
authors.lastname: Silva