Scanning electron microscopy and energy-dispersive X-ray spectroscopy of low-sulfur coal fly ash

Fly ash is a heterogeneous material produced during the burning of pulverized coal in thermoelectric power stations, and its phase and mineral composition includes (i) an inorganic constituent, amorphous and crystalline; (ii) an organic constituent composed of char materials (slightly changed, semicoked and coked particles) and organic minerals; and (iii) fluid constituent. Hence the characterization of fly ash is usually made using several methods. However, scanning electron microscopy (SEM) is the best method and is, along with X-ray diffraction, one of the most widely used techniques for the identification and characterization of phases in fly ash, especially with an SEM equipped with an energy-dispersive X-ray spectrometer (EDS). In this study SEM/EDS was carried out to analyze two high-volatility low-sulfur coals and the fly ash resulting from the combustion of a 50:50 ratio blend of these coals.