Effect of SiO{sub 2} on the Formation of Acicular Calcium Ferrite in Sinter

Journal Article · Mon Apr 15 04:00:00 EDT 2019 · Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science

DOI:https://doi.org/10.1007/S11663-019-01528-W· OSTI ID:22933635

Wang, Wei; Yang, Daiwei; Ou-Yang, Zelin; Xu, Runsheng; Song, Mingming ^[1]

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1. Wuhan University of Science and Technology, The State Key Laboratory of Refractories and Metallurgy (China)

SiO{sub 2} greatly influences the formation of acicular calcium ferrite (ACF), which is the main binder phase in sinter, but the mechanism of its influence is not yet clear. Experiments were carried out under air at 1200 °C with different amounts of SiO{sub 2} mixed with Fe{sub 2}O{sub 3} and Ca(OH){sub 2}. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and three-dimensional (3D) reconstruction were used to characterize the phase and morphological changes of the sintered samples. The results show that SiO{sub 2} can form silicon-ferrite of calcium (SFC), which is beneficial to the formation of ACF in sinter. The SFC content first increased and then decreased with the increasing SiO{sub 2} content. The sintered sample contained the highest contents of SFC and ACF when w(SiO{sub 2}) was 3 to 4 pct. The morphological changes in calcium ferrite observed with the increasing SiO{sub 2} content followed a sequence of massive → platy → acicular; both platy calcium ferrite and ACF were the longest in one direction in their 3D morphology. The inclusion of Si{sup 4+} in calcium ferrite crystals changes the crystal growth habit from having no obvious orientation to having a preferential orientation along the (040) or (320) surfaces, as determined by the first-principles calculations and XRD analysis of block samples. Viscosity was the main environmental factor influencing the size of ACF in samples with sufficient liquid phase.

• OSTI ID: 22933635
• Journal Information: Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science, Journal Name: Metallurgical and Materials Transactions. B, Process Metallurgy and Materials Processing Science Journal Issue: 2 Vol. 50; ISSN 1073-5615; ISSN MTBSEO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AIR
BINDERS
CALCIUM HYDROXIDES
CRYSTAL GROWTH
FERRITES
IRON OXIDES
LIQUIDS
MORPHOLOGICAL CHANGES
MORPHOLOGY
SCANNING ELECTRON MICROSCOPY
SILICON IONS
SILICON OXIDES
SINTERS
SPECTROSCOPY
THREE-DIMENSIONAL CALCULATIONS
VISCOSITY
X-RAY DIFFRACTION