Effect of Furnace Lining Structure on the Flow Field in the 35t Top-blowing Converter Steelmaking Process

Abstract

The main function of the converter furnace lining was to provide a durable container for the high-temperature molten bath. During the steelmaking process, the occurrence of melting corrosion led to the destruction of the furnace lining structure and a subsequent change in the shape of the furnace. Hence, the dynamic condition of the molten bath was altered. In this paper, both water experiment and numerical simulation have been adopted to analyze the flow field characteristic of molten bath by various oxygen lance parameters, in both the initial and late stages of the furnace lining structure of a top-blowing converter. The results revealed the late furnace lining structure improved the average velocity of the molten bath, thereby reducing the mixing time and volume of the low-velocity dead zone, comparing with the furnace lining structure. In the late furnace lining structure, the larger furnace diameter expanded the impaction area of the molten bath, resulting in an enhanced contact area between the liquid slag and the molten steel. Consequently, the FeO in the liquid slag rapidly reacted with the C element in the molten steel, leading to a decrease in the fluidity of the liquid slag and a decline in dephosphorization efficiency. Based on the results generated by water experiment and numerical simulation, two types of new oxygen lances were investigated in the industrial application research. Subsequently, it was determined that the new oxygen lance with an inclination angle of 12.3° was deemed suitable for the 35t top-blowing converter.