Reactions between Different Iron Ores under Condition of Blast Furnace Operation with Hydrogen-enriched Reducing Gas Blowing

The quality of iron ore is expected to change, and blast furnace raw materials will diversify in the future as ores are pretreated to improve ore quality. Furthermore, an increase in the proportion of hydrogen-based reducing agents is necessary to satisfy the demand for carbon neutrality. Therefore, the capacity of blast furnace operations to adapt to these external factors must be enhanced. For stable blast furnace operation even when the external factors change, controlling the cohesive zone is crucial. In this study, the ore-packed beds composed of different ores were reduced by heating up to 1200°C in the atmosphere of a hydrogen-enriched blast furnace. Subsequently, the temperature was increased to 1450°C in an inert atmosphere to investigate the softening and melting behaviors of the samples in contact with different ores. During reduction up to 1200°C, metallic iron was bound between ore particles, while no interparticle migration of gangue components occurred. The unreduced oxide core of the ore melted on heating up to 1450°C, although deformation of the ore did not progress considerably owing to the metallic iron structure. The oxide in the reduced metal shell partially melted, and interdiffusion of the gangue components occurred more than 2 mm from the particle interface.