The Effect of the Pattern of the Cohesive Zone on Silicon Concentration in Molten Metal in the Lower Part of Blast Furnace during Operation

At Oita No.2 blast furnace a phenomena in the lower part of the furnace, in particular between the cohesive zone and the raceway, was measured and observed directly with a belly probe and a core probe during operation. A quantitative relationship was found between the level and the shape of the cohesive zone and the silicon concentration in the molten metal. In the case of an inverse V-shaped cohesive zone, as both inner and outer surfaces of the cohesive zone shifted inwards and downwards, there was a corresponding decrease in the silicon concentration in the molten metal. A decrease in the average distance between the inner surface of the cohesive zone and the tuyere by 0.4m caused a decrease in silicon concentration of 0.3%. In the case of a W-shaped cohesive zone, compared with that of an inverse V-shaped one, a low silicon concentration was obtained by a decrease in SiO gas generation and silicon transfer into the molten metal, which was mainly due to the relatively low temperature and the high FeO content of materials corresponding to the edge of the raceway.