Тип публикации: статья из журнала
Год издания: 2021
Идентификатор DOI: 10.1021/acsomega.1c02880
Аннотация: The composition-structure relationship of blocklike ferrospheres (FSs) isolated from fly ash produced during the combustion of two different types of coal was studied systematically by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Monoblock globules were shown to consist of large sintered crystalliПоказать полностьюtes of Mg, Mn ferrospinel, which are formed from excluded siderite particles containing isomorphic impurities of magnesium and manganese carbonates. The common groups of globules for which the gross composition of polished sections corresponds to the general equations for the relationship of the concentrations SiO2 = f(Al2O3) and CaO = f(SiO2) were highlighted from FSs of two series. These globules are formed during the thermochemical transformation of associates of siderite, quartz, calcite, and anorthite, which have a silicate modulus of SiO2/Al2O3 equal to 1.18, which corresponds to the coefficients in the general equations of the relationship SiO2 = f(Al2O3). SEM analysis of polished cross-sections of the globules of selected FS groups demonstrates that the crystallite size of ferrospinel decreases, while the content of the glass phase increases with the declining FeO concentration in individual globules. The crystallite size and shape are found to depend on the size of the local melt area where the concentration of spinel-forming oxides is >85 wt %. The observed increase in the glass-phase content is attributed to the broadening of the liquation zone in the FeO-Fe2O3-SiO2 system as the oxidative potential increases and to the higher content of [Fe3+O2](-) and [Fe23+O5](4-) ferrite complexes in calcium-rich melts.
Журнал: ACS OMEGA
Выпуск журнала: Vol. 6, Is. 40
Номера страниц: 26004-26015
ISSN журнала: 24701343
Место издания: WASHINGTON
Издатель: AMER CHEMICAL SOC