Heat Transfer Evolution Process in Hearth Based on Blast Furnace Dissection

The abnormal erosion of hearth refractories is widely recognized as the main limiting factor for a long blast furnace life. In this paper, the embrittlement phenomenon of the hearth lining found in the blast furnace dissection has been described. Combining the migration figure of the thermocouple temperature in the blast furnace hearth, the evolution process of the carbon brick erosion and the heat transfer were analyzed. The results show that the embrittlement layer contains a large amount of ZnO, which accounts for more than 40%, and the thermal conductivity of the embrittled carbon brick is about 4.9 W/(m K). Moreover, due to the detachment of the embrittlement layer, the erosion evolution process of the hearth carbon brick exists as a cyclically periodic rising phenomenon together with the thermocouple temperature. Thereafter, the residual thickness of the carbon bricks and the temperature of the thermocouples during the formation of the embrittlement layer and the protective layer were calculated quantitatively.