Optimizing MgO distribution between sinter and pellet based on melting behavior and interaction

Abstract

During blast furnace ironmaking, MgO flux is added to the sinter or pellets to reduce the viscosity and improve the desulfurization capacity of the slag. The distribution of total MgO addition between the sinter and pellets affects the interaction between the ferrous burdens. Inappropriate interaction between different burdens promotes the formation of an excessive amount of low-melting-point liquid phases, which reduces the permeability of the cohesive zone. In this study, the effect of MgO on the interaction between the sinter and pellets was visualized during heating and further investigated using thermodynamic calculations. A new concept named the distribution index of MgO was proposed for optimizing the MgO distribution between the sinter and pellets. A trade-off between the permeability and interaction between burdens in the cohesive zone was observed, which can be addressed by postponing the interaction between burdens to a higher temperature (i.e., a lower part of the cohesive zone).