Interfacial reaction behavior in blast furnace and analysis of influence mechanism

Abstract

This study aims to explore the influence mechanism of interfacial reaction in BF. The interfacial reaction behavior was analyzed, the thermodynamic and evolution processes of interfacial reaction were studied, and the influence of interfacial reaction on BF was discussed. The results show that: The desulfurization reaction mechanism can be considered as the electron transfer at slag-iron interface. The viscosity of molten iron shows a decreasing trend with the increase of sulfur content, and the surface tension of molten iron will rapidly decrease with sulfur content, so the interfacial reaction rate will be accelerated. The reduction of FeO occurs at slag-carbon interface, the content of FeO in slag often shows a decreasing trend along the height direction of BF, the erosion rate of carbon brick will increase under the condition of slag with high FeO content. The reduction of SiO2 is achieved with the help of two gas-phase compounds SiO and SiS. The average Si content in molten iron decreases with the increase of BF volume, which indicates that the large BF is more conducive to achieving low-carbon smelting. The reduction of TiO2 is carried out at the slag-carbon interface step by step, the valence state of Ti element gradually decreases. The iron-carbon interface in hearth has a significant effect on the erosion of carbon brick and the state of hearth. The wetting and erosion process at iron-carbon interface is clarified based on the cycle model, the carbon brick is eroded in this cycle. The time for the carburization of molten iron is limited, so the carbon content of molten iron cannot reach saturation, although there are a large number of iron-carbon interfaces in hearth. The change trend of maximum temperature on sidewall is opposite to the actual carbon content, the change in carburization behavior at iron-carbon interface is the essential reason for the fluctuation of erosion rate of carbon brick.