Sulfur-bearing coatings on fly ash from a coal-fired power plant: Composition, origin, and influence on ash alteration

Fuel
By: , and 

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Abstract

Fly ash samples collected from two locations in the exhaust stream of a coal-fired power plant differ markedly with respect to the abundance of thin (≈0.1 μm) sulfur-rich surface coatings that are observable by scanning electron microscopy. The coatings, tentatively identified as an aluminum-potassium-sulfate phase, probably form upon reaction between condensed sulfuric acid aerosols and glass surfaces, and are preferentially concentrated on ash exposed to exhaust stream gases for longer. The coatings are highly soluble and if sufficiently abundant, can impart an acidic pH to solutions initially in contact with ash. These observations suggest that proposals for ash use and predictions of ash behavior during disposal should consider the transient, acid-generating potential of some ash fractions and the possible effects on initial ash leachability and alteration.

Publication type Article
Publication Subtype Journal Article
Title Sulfur-bearing coatings on fly ash from a coal-fired power plant: Composition, origin, and influence on ash alteration
Series title Fuel
DOI 10.1016/S0016-2361(98)00146-X
Volume 78
Issue 2
Year Published 1999
Language English
Publisher Elsevier
Description 10 p.
First page 187
Last page 196
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