E. Cereda et al., THE MICROSCOPIC NATURE OF COAL FLY-ASH PARTICLES INVESTIGATED BY MEANS OF NUCLEAR MICROSCOPY, Atmospheric environment, 29(17), 1995, pp. 2323-2329
Individual fly ash particles collected at the outlet of a pilot electr
ostatic precipitator of a coal-fired power plant have been analysed by
a proton microprobe. Major and trace element concentrations have been
obtained for about one hundred particles in the 0.5-5 mu m size range
. As a result of the combustion of the different components of the min
eral matter in the parent coal, particles can be grouped in seven clas
ses showing characteristic matrix compositions and different trace ele
ment concentrations. The relative abundances of these groups seem to h
ave a size dependence. Trace elements are found to be non-uniformly di
stributed over all particles: a size dependence as well as some prefer
ential association with the particle matrix have been found. Enriched
concentrations of potentially toxic elements exist on smaller, most re
spirable particles examined in this study, Possible reasons for this a
re suggested.