酸化鉄−カルシウムフェライト混合試料の還元速度における鉱物粒度の影響

概要

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It is important to know the reduction kinetics of iron ore sinter that is main iron resource of blast furnace. Iron ore sinter has various mineral phases such as hematite, magnetite and calcium ferrite, and equilibrium gas compositions of these minerals are different. Size and shape of these mineral phases are various, and these morphology is related in the reduction rate of iron ore sinter. However relationship between size of mineral phase and reduction rate has not been researched. In this study, we clarified the relationship between them.We prepared mixed samples made from iron oxide having particle size range of -45, 45-75, 75-125 and 125-250 μm and calcium ferrite having particle size range of -45, 45-75 and 75-125 μm. The reduction experiments were carried out with 100% CO.The results obtained in this study are follows:(1)The effect of particle size under 250 μm on the reduction rate was negligible below 1000°C. It caused by the reduction degradation of iron oxide reduced from hematite to magnetite during pre-reduction.(2)Reduction of mixed samples having particle size 125-250 μm of iron oxide and 45-75 μm of calcium ferrite at 1100°C were extremely slow. It is caused by the formation of melt having three-component system of Al2O3-CaO-FeO.