Computer-controlled scanning electron microscopy (CCSEM) investigation of quartz in coal fly ash

Computer-controlled scanning electron microscopy (CCSEM) and X-ray diffraction (XRD) were used to investigate Si-rich phases in several coal fly ash (CFA) samples. The CCSEM measurements utilized both particle size distributions and a particle shape parameter, circularity, to classify the Si-rich phases in these ashes. The results indicated that the amount of free, respirable, crystalline quartz in these CFA samples was very small (< 1.0 vol.% ). Neither the total quartz nor the respirable quartz determined by CCSEM showed a significant correlation with the XRD results for the bulk ash.