A systematic study employing scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS) of ferrospheres isolated from the fly ash formed in the combustion of pulverised coal of the Kuznetsk basin allowed us to determine the glass phase composition. The groups of globules have been identified for which the gross composition of polished sections exhibits a linear correlation between the content of glass-forming silicon and calcium oxides. Heterogeneity of the glass phase of the studied ferrospheres in composition and the number of its components was established. It is shown that iron is mainly found in the crystallites of iron-containing phases, and silicon is in the glass phase. The remaining elements are distributed between these phases. It is shown that ferrospheres contain microglobules of varying compositions, with sizes of less than 1 μm, localized in the amorphous glass phase. Their presence determines the chemical heterogeneity of the glass phase. The composition of microglobules, like the composition of ferrospheres as a whole, is determined by the mineral components of the original coal. The precursor for the formation of the glass phase of ferrospheres are aluminosilicates of original coal.
ANSHITS et al. (Tue,) studied this question.