Quantitative Evaluation of Reaction Mode and Reduction Disintegration Behavior of Iron Ore Agglomerates during Low Temperature Reduction

摘要

The utilization of H_2 in the ironmaking process is a potential option for a further reduction of CO_2 emission from the blast furnace (BF). H_2 promotes the reduction reaction of burden materials, but its influence on their reduction disintegration behavior remains unknown in detail. This study investigates its influence on the specified essential factors governing the reduction disintegration behavior of the iron ore agglomerates, i.e., iron ore sinters and pellets. Reduction disintegration index (RDI) values were measured after the reduction of the agglomerate samples using the gas mixtures of CO-H_2-CO_2-N_2. The mineral textures of reduced samples were observed using an optical-microscope and an electron probe micro-analyzer for the evaluation of reaction modes. Further, Thiele modulus (φ), which is considered as the index of reaction modes during reduction, was calculated using the measurement results. The calculated φ showed reasonable correlation with RMI values, which is one index of the reaction mode evaluated by an elemental analysis using EPMA. Disintegration does not make much progress when φ is larger than a certain limit value, whereas it proceeds significantly when φ is less than that value.