What are the spheroidal fly ash particles?
In the case of high temperature during the combustion process ashes from the furnaces of thermoelectric power plants, central heating systems and several industrial processes (e.g. metallurgy) contain certain particles of spheroidal form. There exist two principal types of spheroidal particles (see Fig.1): • formed due to incomplete combustion of the organic part of fuel, composed mainly of inorganic carbon; • formed by the fusing of mineral material within the fuel, composed mainly of alumosilicate glassy material. The first type is dominating in the emissions of liquid fuel (mainly oil products) combustion. The second type is more frequent in the ashes of solid fuels (coal, oil shale, brown coal, peat), although the carbonaceous particles exist in these ashes, too. Scanning electron microscopy and energy-dispersive x-ray spectroscopy analysis of individual fly ash particles have shown that particle morphology and composition is in some extent indicative to the fuel burnt and could be
