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In this study, the effects of adding metallic Fe particles to coke in an effort to reduce the CO2 emissions associated with sintering were investigated. The changes to the structure and permeability of the sintering bed were analyzed in a laboratory-scale sintering simulator. The results were then used to compare agglomerates material containing metallic Fe particles with a 100% coke bed. The pressure drop of the packed bed of the mixture of model mini-pellets (ACPs) and coke particles increases until the bed reaches the temperature at which the adhering layer of ACP starts to melt, and then starts to gradually decrease. The pressure drop for metallic Fe particles, however, begins to decrease at an earlier stage, and then increases until its peak value. This difference can be attributed to differences in the products formed from oxidation.The sintering experiments were made by making changes to the CaO composition of the sintering bed: 5% to 15% was substituted with metallic Fe particles. A high CaO content resulted in a lower pressure drop of the bed from the start to 200 s sintering apparently due to the difference in the melting behavior of the materials at the initial stage of sintering.

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緒言Synopsis : This study has been performed to understand the characteristic of KR slag, which is a by-product of the desulfurization process of steel, aiming at its effective utilization in the iron ore sintering process. KR slag contains CaO, metallic iron and FeO component and has been partly utilized in the sintering process as CaO source. However, its oxidation behavior has not been evaluated. Effective utilization of KR slag will lead to reduction of CO 2 emission by decreasing the amount of coke breeze and increase the ratio of formed melt during sintering. Oxidation and melting behaviors of KR slag in the sintering bed were examined by using a laboratory-scale sintering simulator. Higher oxidation ratio was obtained for KR slag than that for metallic iron particle. Iron oxide layer formed on the surface of iron particles in KR slag were easily melted and it would keep the oxidation rate of metallic iron at a certain level. The effect of mixing ratio of KR slag on the structure and permeability of the sintering bed was examined. The amount of formed melt increased with increase in the mixing ratio of KR slag.On the other hand, when the melt ratio became to be above 15%, bed permeability was significantly decreased. This would be caused by blocking the gas flow path in the sintering bed with the excess amount of melt. Therefore, mixing ratio of KR slag is necessary to control the melt ratio below 15%.