EXPERIMENTAL STUDIES OF SLAG FLOW IN THE BLAST FURNACE HEARTH DURING TAPPING OPERATION.

Abstract

To clarify the causes of excess accumulation of molten materials in the blast furnace hearth which causes such trouble as hanging and slipping, the flowing out and accumulation of slag in the hearth were studied by model experiments. The results were analyzed as the scale-up problem based on the theories of fluid dynamics. The influential factors such as the porosity epsilon , the shape factor phi , and the mean diameter d of the coke bed in the hearth, the viscosity mu , the density rho , and the superficial velocity V//0 of the slag, the depth of slag layer at the beginning of its flow-out H and the hearth diameter D were combined to give the dimensionless ″flow-out coefficient″ F//L, which is found to be closely related to the ratio of residual slag alpha , i. e. , the ratio of the amount of residual slag at the end of tapping to that accumulated at the beginning, in such a manner that an increase in F//L causes an increase in alpha . The experimental conditions had been selected so that the results could be applied directly to the slag flow in the blast furnace hearth. The amount of residual iron is estimated to be less than one-tenth of the amount of residual slag at the end of tapping.