8th International Congress on Science and Technology of Ironmaking - ICSTI 2018

For decreasing CO2 emission from iron making process, increasing hydrogen concentration in blast furnace is suitable method. However, the property of iron ore agglomerate such as reducibility should be optimized because hydrogen reduction is endothermic reaction and temperature distribution in BF drastically changes by increasing hydrogen concentration. In this study, the effect of hydrogen concentration on the reduction behavior of mineral phases in iron ore sinter is evaluated. Ten sinter samples which were produced by Japanese steel mill were used. The composition of the mineral phases in these samples was analyzed by XRD and image analysis. Sinter sample was reduced under the simulated conditions such as standard (N2 - 48%(CO+CO2) - 5.8%(H2+H2O)) and high hydrogen (N2 - 48%(CO+CO2) - 13%(H2+H2O)). After reduction, microstructure of the sample was observed. Sinter has components of hematite, magnetite, calcium ferrite and slag. Furthermore, calcium ferrite could be divided into four types which were acicular calcium ferrite with primary hematite (1H-ACF), columnar one with secondary hematite (2H-CF), small columnar one with magnetite, and large columnar one with magnetite. Increase in hydrogen concentration accelerates the reduction of hematite, 1H-ACF, and 2H-CF in all sinter samples while the reduction of magnetite, and calcium ferrite with magnetite is not done.