Characterization of fly ash directly collected from electrostatic precipitator

Class-F fly ash was obtained from different hoppers at progressively farther distances from the boiler. Examinations showed that the ash collected from the farthest hopper tended to have finer particle size, greater density, lower carbon content, and higher glass content. When the boiler is operated at full load (600 MW) the glass content:increased compared to half load (300 MW), but the Blaine specific surface area and carbon content decreased. Pozzolanic reactivity at 40 degrees C is related to the fineness of the fly ash but the glass content has no significant influence on reactivity. There was a negative correlation between carbon content and the apparent viscosity of cement paste with fly ashes and 1.6% added superplasticizer. (C) 1999 Elsevier Science Ltd. All rights reserved.