2022 年 62 巻 8 号 p. 1624-1628
The phase evolution during heating of two Al2O3-free mixtures designed to form the SFC iron ore sinter bonding phase was investigated using in-situ X-ray diffraction over the temperature range 293–1623 K. Results showed that during heating at an oxygen partial pressure of 5 × 10−3 atm, SFC formation was preceded by the formation of γ-Ca4Fe14O25 and γ-CFF (nominal composition Ca3.0Fe14.82O25) intermediate phases. On further heating the SFC melted to form Fe3O4 in a Fe2O3–FeO–CaO–SiO2 melt. During heating of one of the mixtures in air, it was not possible to distinguish between SFCA-I and α-CFF (nominal composition Ca3.43Fe14.39O25) as intermediate phases in the formation of SFC. The improved signal-to-noise ratio and angular peak resolution afforded by synchrotron-based XRD experimentation would be required to possibly distinguish between these two phases. Regardless of whether SFCA-I or α-CFF formed as intermediate phases during heating in air, this work shows that the oxygen partial pressure has a significant effect on phase formation mechanisms in the Al2O3-free SFC system.
