STRUCTURAL AND PHASE TRANSFORMATIONS IN THE FeO-SiO2 CaO-FeO I SYSTEM AT INFLUENCE OF HIGH TEMPERATURES

In work structural and phase transformations in two-component the iron oxides systems are considered at high-temperature influence, on the example of bivalent oxide of iron and oxides of calcium and silicon, by the being one of the main components of cement binding. Taking into account structure of a radiation protective composite ratios of FeO:CaO =2:1 and FeO:SiO2=4:1 are considered. Heat treatment of the FeO:CaO system in the recovery environment intensified dissociation of calcite and displaced her to the low temperatures area (from 700-1000 °C in the oxidizing environment to 600–800 °C) that is caused by influence of iron of various valency (first of all magnetite) on an ionic lattice of calcite. At 600 °C there is a formation of monocalcic ferrite. In process of enrichment of the СаО system in the range of 700–800 °C monocalcic ferrite passed into two-calcic. Formation of ferrite happens at continuous change of a valent and coordination condition of ions of iron and degree of an ionnost and covalence of a chemical bond of Fe-O in ferriferous complexes. In the FeO-SiO2 system it is established: modification transition of quartz in kristobalit began at 800 °C and intensively develops at 900 °C, against 1200 °C in oxidizing conditions; to modification transition of quartz in kristobalit formation of silicon dioxide with partially amorphous structure in the range of 600–700 °C consisting of ring structural elements from [SiO4] - tetrahedrons preceded.