Fundamentals of Silico-Ferrite of Calcium and Aluminum (SFCA) and SFCA-I Iron Ore Sinter Bonding Phase Formation: Effects of MgO on Phase Formation During Heating

The formation and decomposition of silico-ferrite of calcium and aluminium (SFCA) and SFCA-I iron ore sinter bonding phases have been investigated using in situ synchrotron and laboratory X-ray diffraction (XRD) and neutron diffraction (ND). An external standard approach for determining absolute phase concentrations via Rietveld refinement-based quantitative phase analysis is discussed. The complementarity of in situ XRD and ND in characterising sinter phase formation and decomposition is also shown, with the volume diffraction afforded by the neutron technique reducing errors in the quantification of magnetite above ~1200 °C. Finally, by collecting 6 s laboratory XRD datasets and using a heating rate of 175 °C min−1, phase formation and decomposition have been monitored under heating rates more closely approximating those encountered in industrial iron ore sintering.

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Effect of alumina and silica content in the calcium aluminosilicoferrite Ca2(Ca,Fe,Mg)6(Fe,Si,Al)6O20 bonding phase on the strength of iron ore sinter

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2020.123733 ◽

2021 ◽

Vol 257 ◽

pp. 123733

Author(s):

Roland Mežibrický ◽

Tamás Csanádi ◽

Marek Vojtko ◽

Mária Fröhlichová ◽

Rainer Abart

Keyword(s):

Iron Ore ◽

Silica Content ◽

Iron Ore Sinter ◽

Bonding Phase

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Fundamentals of silico-ferrite of calcium and aluminium (SFCA) and SFCA-I iron ore sinter bonding phase formation: effects of mill scale addition

Powder Diffraction ◽

10.1017/s088571561700080x ◽

2017 ◽

Vol 32 (S2) ◽

pp. S85-S89 ◽

Cited By ~ 5

Author(s):

Nathan A. S. Webster ◽

Mark I. Pownceby ◽

Rachel Pattel

Keyword(s):

Iron Ore ◽

Amorphous Material ◽

Quantitative Phase Analysis ◽

X Ray Diffraction ◽

Mill Scale ◽

Iron Ore Sinter ◽

External Standard Method ◽

Mineral Sample ◽

Sinter Bonding

The thermal decomposition of mill scale, and the effect of mill scale addition on the formation and decomposition of Silico-Ferrite of Calcium and Aluminium (SFCA) and SFCA-I iron ore sinter bonding phases, has been investigated using in situ X-ray diffraction. Application of the external standard method of quantitative phase analysis of the in situ data collected during decomposition of the mill scale highlighted the applicability of this method for the determination of the nature and abundance of amorphous material in a mineral sample. Increasing mill scale addition from 2.6 to 10.6 and to 21.2 wt% in an otherwise synthetic sinter mixture composition designed to form SFCA did not significantly affect the thermal stability ranges of SFCA-I or SFCA, nor did it significantly affect the amount of each of SFCA or SFCA-I, which formed. This was attributed to the low impurity (i.e. Mn, Mg) concentration in the mill scale, and also the transformation to hematite during heating of the wüstite and magnetite present in the mill scale, with the hematite available for reaction to form SFCA and SFCA-I.

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In situX-ray diffraction analysis of iron ore sinter phases

Journal of Applied Crystallography ◽

10.1107/s002188980400353x ◽

2004 ◽

Vol 37 (3) ◽

pp. 362-368 ◽

Cited By ~ 52

Author(s):

Nicola V. Y. Scarlett ◽

Ian C. Madsen ◽

Mark I. Pownceby ◽

Axel N. Christensen

Keyword(s):

Iron Ore ◽

Rietveld Method ◽

Structural Type ◽

X Ray Diffraction ◽

X Ray ◽

Intermediate Phases ◽

Iron Ore Sinter ◽

Phase Quantification ◽

Bonding Phase

Owing to the depletion of world lump iron ore stocks, pre-treated agglomerates of fine ores are making up a growing proportion of blast-furnace feedstock (∼80%). These agglomerations, or `sinters', are generally composed of iron oxides, ferrites (most of which are silicoferrites of calcium and aluminium, SFCAs), glasses and dicalcium silicates (C2S). SFCA is the most important bonding phase in iron ore sinter, and its composition, structural type and texture greatly affect its physical properties. Despite its prevalence and importance, the mechanism of SFCA formation is not fully understood.In situpowder X-ray diffraction investigations have been conducted into the formation of SFCA, allowing the study of the mechanism of its formation and the observation of intermediate phases with respect to time and temperature. Studies have been carried out to investigate the effects of changing the substitution levels of aluminium for iron. The use of the Rietveld method for phase quantification gives an indication of the order and comparative rates of phase formation throughout the experiments.

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