Effect of Temperature, Time, and Cooling Rate on the Mineralogy, Morphology, and Reducibility of Iron Ore Sinter Analogues

Abstract

Analogue sinter tablets were produced at temperatures between 1250°C and 1320°C, with a range of hold times and cooling rates. Platy silico-ferrite of calcium and aluminum (SFCA) morphology was identified in samples produced at 1250°C using reflected light microscopy; however, quantitative x-ray diffraction (XRD) identified the presence of the SFCA phase, with no SFCA-I detected. This proves that the platy SFCA morphology common in analysis by reflected light microscopy cannot be attributed to the SFCA-I mineral without further analysis. Micro-XRD and electron probe micro-analysis (EPMA) were carried out on an area of platy SFCA confirming this result. The sinter analogue tablets were reduced in a 30% CO, 70% N2 gas mixture at 900°C in a tube furnace thermo-gravimetric analyzer. The degree of reduction of the tablets in this study was found to be controlled by the porosity of the samples, rather than by the morphology or mineralogy of the bonding phase.

A Study on the Effect of Alumina on the Morphology and Reduction Behavior of Sinter by In Situ Observation

“…Therefore, in determining the reduction rate of the sinter, the influence of the microstructure on the diffusion of the reducing gas is more significant than that of the ICR due to the formation of the SFCA phase. Kato et al [24] and Harvey et al [25] have also reported that the microstructure is a more important influencing factor than the iron oxide reactivity in sinter reduction. The GMT rate constants (R.D > 33% region) were derived from the results of this experiment, and the results of the porosity analysis on the sample prior to reduction are shown in Figure 10.…”

Quantification of Resistance and Pressure Drop at High Temperature for Various Suction Pressures During Iron Ore Sintering

“…Tejbir SINGH, 1) Subhasish MITRA, 1) Damien O'DEA, 2) Lydia KNUEFING 3) and Tom HONEYANDS 1) * 1) Centre for Ironmaking Materials Research, School of Engineering, The University of Newcastle, Callaghan, NSW, 2308 Australia.…”

A Short Review of the Effect of Iron Ore Selection on Mineral Phases of Iron Ore Sinter

“…The liquid phase served as a binding material between residual iron oxide particles. When the iron ore sinter was cooled, SFCA, SFCA-I, and other calcium ferrites were formed [37][38][39]; dicalcium silicate, alumina, quartz, and glass were also present as minor mineral phases. SFCA in the iron ore sinter appeared in different forms (columnar, acicular, prismatic, platy, etc.…”

“…Most of the sinter quality (reducibility and degradation degree) was affected by the amount and shape of SFCA [35,[40][41][42][43][44][45][46][47]. As the cooling rate increased, the fractions of columnar and platy type (SFCA, SFCA-I) increased [39]. Furthermore, the fraction of columnar type increased with the Al 2 O 3 content.…”

“…MgO inhibited the formation of SFCA [48]. On the other hand, LOI reduced the sintering temperature [49] and thereby decreased the amount of SFCA formed in the iron ore sinter [39]. Some parts of hematite particles were reduced to magnetite during the sintering process, and they were reoxidized during the cooling process, resulting in the formation of secondary hematite.…”