Characterization of Ca(OH)2/fly ash sorbents for flue gas desulfurization
Resource
POWDER TECHNOLOGY 131(2-3), 212-222
Journal
POWDER TECHNOLOGY 131(2-3)
Pages
212-222
Date Issued
2003
Date
2003
Author(s)
Lin, Ren-Bin
Shih, Shin-Min
DOI
246246/2006111501233354
Abstract
Ca(OH)2/fly ash sorbents prepared by varying the Ca(OH)2/fly ash weight ratio (CH/FA) and the slurrying time at 65 jC and a water/solid
ratio (L/S) of 10:1 were characterized to study the influence of the preparation variables on their physical properties and chemical
compositions. The pozzolanic reaction between Ca(OH)2 and fly ash taking place in slurry resulted in the formation of calcium silicate
hydrates (CSHs) (C–S–H(I)), which, having shapes of foil, plate, and sphere, tended to cause particles to cohere and to form a porous
structure. Particles formed by foils of calcium silicate hydrates were compressible under high pressures. The reaction was rapid before 1 h
and abruptly slowed down thereafter due to the covering of fly ash particles by calcium silicate hydrates; but the structure of calcium silicate
hydrates continued to change with slurrying time, hence more pore volume and surface area were generated. Pores in the sorbents were
mainly in the mesopore range and slit-shaped. The particle sizes, specific surface areas, and pore volumes of the sorbents, being larger than
those of Ca(OH)2 or fly ash alone, changed with Ca(OH)2/fly ash weight ratio. The sorbent with a ratio of 70:30 had the largest specific
surface area, mesopore volume, and micropore volume.
Subjects
flue gas desulfurization
Ca(OH)(2)
fly ash
structural properties
pollution control
Publisher
Taipei:National Taiwan University Dept Chem Engn
Type
journal article
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