Geochemistry of ultra-fine and nano-compounds in coal gasification ashes: A synoptic view

Marcio A. Kronbauer, Maria Izquierdo, Shifeng Dai, Frans B. Waanders, Nicola J. Wagner, Maria Mastalerz, James C. Hower, Marcos L.S. Oliveira, Silvio R. Taffarel, Delmar Bizani, Luis F.O. Silva

Research output: Contribution to journalArticlepeer-review

91 Scopus citations

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.

Original languageEnglish
Pages (from-to)95-103
Number of pages9
JournalScience of the Total Environment
Volume456-457
DOIs
StatePublished - Jul 1 2013

Bibliographical note

Funding Information:
The research for this study was carried out with support from the Institute of Environmental Research and Human Development (IPADH) . The authors thank the CNPq, the FAPERGS, and the Electron Microscopy Center of the Federal University of Rio Grande do Sul for the analyses. Marcos L. S. Oliveira and Luis Silva benefited from a scholarship financed by CNPq, Brazil — ref: 382954/2011-4 and processo: 380649/2011-0 .

Keywords

  • Ash
  • Coal
  • Hazardous elements
  • IGCC
  • Nanoparticle morphology

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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