Oxidation characteristics of metallic iron and magnetite concentrate with coke in sintering bed

This study has been performed to clarify the oxidation characteristics of iron-bearing agglomeration agents charged with coke in the iron ore sintering bed as an approach toward the reduction of CO₂ emissions from the sintering process. A series of oxidation experiments were carried out for metallic iron particles and magnetite concentrate pellets using laboratory-scale sintering simulator, which gave the changes in their O₂ consumption rate and reaction ratios during sintering. When metallic iron particles were used with coke, oxidation reaction of metallic iron was suppressed at an initial few seconds in the case of 25% metallic iron addition. However, it was not suppressed in the case of the higher metallic iron addition. The final oxidation ratio of metallic irons was approximately 0.8 in any case of the mixing ratio. When magnetite pellet and that containing 20 mass%CaO were used as agglomeration agent for sintering, reaction ratio of the former was always higher than that of the latter. It suggests that melt-formation led to a decrease in the specific surface area for the oxidation reaction. When magnetite pellets were charged with coke, oxidation of magnetite was suppressed by a decrease in the oxygen partial pressure around the burning coke particles.