Development of a Slag Viscosity Estimation Model in Consideration of the Deposition of the Solid Phase

Abstract

The viscosity of slag is a very important factor for blast furnace operation. For instance, the viscosity of slag exerts a big influence on the liquidity of slag in the hearth, the tapping of pig iron and slag, softening, shrinkage, melting down, permeability in the cohesive zone, and permeability in the deadman. In addition, the viscosity of slag itself is affected by temperature and composition changes when the slag is formed. Furthermore, the fact that slag viscosity is greatly increased by the deposition of coke powder and the solid phase is well known.
However models that consider such effects are few.
Therefore, we have developed an estimation model that takes into account the increase in the viscosity of slag due to the deposition of the solid phase. The calculation result of the model was in good agreement with the measured results.
As an example application of the estimation formula, we have examined the melting point and viscosity of the slag of quaternary Al₂O₃-SiO₂-CaO-MgO along with slag containing FeO.