Title

THE EFFECT OF INITIAL MELT FORMATION ON THE REDUCIBILITY OF IRON ORE AGGLOMERATES

THE EFFECT OF INITIAL MELT FORMATION ON THE REDUCIBILITY OF IRON ORE AGGLOMERATES

Authorship

Takeuchi, Eiichi; Kawabata, Hirotoshi; Konishi, Hirokazu; Ono, Hideki; Higuchi, Kenichi; Nishimura, Tsunehisa

Takeuchi, Eiichi

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Kawabata, Hirotoshi

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Konishi, Hirokazu

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Ono, Hideki

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Higuchi, Kenichi

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Nishimura, Tsunehisa

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DOI

10.5151/2594-357X-22732

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Abstract

In order to utilize the lower quality of iron ore with high Al2O3 content, it is important to understand the effect of Al2O3 in iron ore agglomerates on their reducibility. The iron ore agglomerates(tablet type) of FeO-CaO-SiO2-Al2O3 were synthesized for the reduction experiments under 30vol%CO-70vol%N2 gas mixture from 1000 to 1200°C in the rate of 5°C/min, in which Al2O3 content was changed from 0 to 4 mass%. The reducibility in the higher temperature region (>1100°C) deteriorates by increasing Al2O3 content. In-situ observations of the melt formation of slag in artificial iron ore agglomerates were conducted by using the scanning laser microscope mounted with the heating device. It was found that the main cause is the blockage of gas diffusion into the unreacted region of tablet due to the initial melt of oxide which occupies the micro pores in the tablet. The temperature of initial melt formation decreases and the amount of melt increases with increasing Al2O3 content. The deterioration of reducibility is thus explained by the formation of a molten oxide and its penetration to the micro pores in an unreacted region.

In order to utilize the lower quality of iron ore with high Al2O3 content, it is important to understand the effect of Al2O3 in iron ore agglomerates on their reducibility. The iron ore agglomerates(tablet type) of FeO-CaO-SiO2-Al2O3 were synthesized for the reduction experiments under 30vol%CO-70vol%N2 gas mixture from 1000 to 1200°C in the rate of 5°C/min, in which Al2O3 content was changed from 0 to 4 mass%. The reducibility in the higher temperature region (>1100°C) deteriorates by increasing Al2O3 content. In-situ observations of the melt formation of slag in artificial iron ore agglomerates were conducted by using the scanning laser microscope mounted with the heating device. It was found that the main cause is the blockage of gas diffusion into the unreacted region of tablet due to the initial melt of oxide which occupies the micro pores in the tablet. The temperature of initial melt formation decreases and the amount of melt increases with increasing Al2O3 content. The deterioration of reducibility is thus explained by the formation of a molten oxide and its penetration to the micro pores in an unreacted region.

Keywords

Iron ore agglomerate; Reducibility; FeO-CaO-SiO2-Al2O3 system; Al2O3 content; Initial melt formation.

Iron ore agglomerate; Reducibility; FeO-CaO-SiO2-Al2O3 system; Al2O3 content; Initial melt formation.