Effect of Types of Carbonaceous Material and CaO Addition on Reduction Behavior of Pre-reduced Iron Ore–Carbon Composite

摘要

Utilization of iron ore-carbon composite for blast furnace has a possibility of the method to decrease carbon dioxide emission from iron and steel industry. Major iron ores consist of Fe_(2)O_(3), Fe_(3)O_(4), and FeOOH, which require several reduction steps through FeO to form metallic iron. When graphite and pure FeO obtained by pre-reduction are used for the raw material of composite, the reduction of iron oxide proceeds at lower temperature than that using conventional iron ore. In the actual process, raw materials such as iron ores and coke contain impurities of silica, alumina and sulfur. Furthermore, limestone is used as fluxing materials to control basicity of slag. In this study, the effect of types of carbonaceous materials and CaO addition on the reduction behavior of the composite using FeO prepared by pre-reduction was examined. Reduction temperatures of FeO composite using coke and biomass char were higher than that using graphite. The reason can be explained by the effect of sulfur contained in the carbonaceous materials. The addition of CaO which reacted with sulfur led to lowering the reduction temperature.