In situ x-ray diffraction investigation of the formation mechanisms of silico-ferrite of calcium and aluminium-I-type (SFCA-I-type) complex calcium ferrites
Loading...
Date
2013-01-01
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
The Iron and Steel Institute of Japan
Abstract
The formation mechanisms of the complex Ca-rich ferrite phase SFCA-I, an important bonding material in iron ore sinter, during heating of synthetic sinter mixtures in the temperature range 298-1623 K in air and at pO(2) = 5 x 10(-3) atm, were determined using in situ X-ray powder diffraction. In air, the initial formation of SFCA-I at similar to 1438 K (depending on composition) was associated with reaction of precursor phases Fe2O3, CaO center dot Fe2O3, SiO2, amorphous AI-oxide and a CFA phase of approximate composition 71.7 mass% Fe2O3, 12.9 mass% CaO, 0.3 mass% SiO2 and 15.1 mass% Al2O3. At temperatures above similar to 1453 K, the decomposition of another phase, gamma-CFF, resulted in the formation of additional SFCA-I. At lower oxygen partial pressure the initial formation of SFCA-I occurred at similar temperatures and was associated with reaction between similar phases as its formation in air. However, the decomposition of gamma-CFF did not result in the formation of additional SFCA-I, with the maximum SFCA-I concentration (25 mass%) lower than the values attained in air (54 and 34 mass%). Hence, more oxidising conditions appear to favour the formation of the desirable SFCA-I phase. Copyright © The Iron and Steel Institute of Japan 2013.
Description
Keywords
Iron ores, Ores, Diffraction, X-ray diffraction, Crystal structure, Crystals
Citation
Webster, N. A. S., Pownceby, M. I., & Madsen, I. C. (2013). In situ x-ray diffraction investigation of the formation mechanisms of silico-ferrite of calcium and aluminium-I-type (SFCA-I-type) complex calcium ferrites. ISIJ International, 53(8), 1334-1340. doi:10.2355/isijinternational.53.1334