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This article in JEQ

  1. Vol. 31 No. 3, p. 979-988
    Received: Apr 18, 2001

    * Corresponding author(s): laperche@cnrssp.org
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Quantitative, Chemical, and Mineralogical Characterization of Flue Gas Desulfurization By-Products

  1. Valérie Laperche *a and
  2. Jerry M. Bighamb
  1. a CNRSSP, 930 Boulevard Lahure, 59505 Douai cedex, France
    b Ohio State Univ., School of Natural Resources, 2021 Coffey Road, Columbus, OH 43210


The objective of this study was to demonstrate that simple fractionation and selective dissolution techniques can be used to provide detailed chemical and mineralogical analyses of flue gas desulfurization by-products. The material studied was a mine grout prepared as a 1:1 mixture (wt./wt.) of fly ash (FA) and filter cake (FC) with hydrated lime (50 g kg−1) added to improve handling. The hydrated lime was composed mostly of calcite (CaCO3), portlandite [Ca(OH)2], lime (CaO), and brucite [Mg(OH)2] (515, 321, 55, and 35 g kg−1, respectively) and had low (<6 g kg−1) concentrations of most trace elements. The FC contained hannebachite (CaSO3·0.5H2O) (786 g kg−1) with smaller quantities (<10 g kg−1) of calcite, quartz (SiO2), brucite, and gypsum (CaSO4·2H2O). Except for B and Cu, trace element concentrations were comparable to those in the hydrated lime. The FA contained both magnetic (222 g kg−1) and nonmagnetic (778 g kg−1) fractions. The former was composed mostly of hematite (Fe2O3), magnetite (Fe3O4), and glass (272, 293, and 287 g kg−1, respectively), whereas the latter was enriched in glass, quartz, and mullite (Al6Si2O13) (515, 243, and 140 g kg−1, respectively). Etching with 1% HF showed that 60 to 100% of trace elements were concentrated in the glass, although some metals (Co, Cr, and Mn) were clearly enriched in the magnetic phase. The aged grout contained 147 g kg−1 ettringite [Ca6Al2(SO4)3(OH)12·26H2O] in addition to 314 g kg−1 hannebachite and 537 g kg−1 insoluble phases (mullite, quartz, hematite, magnetite, and glass).

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Copyright © 2002. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyPublished in J. Environ. Qual.31:979–988.