Softening-melting- dripping behavior of sinter in a hydrogen-rich blast furnace

Abstract

Hydrogen-rich blast furnace is one of the most important approaches to low-carbon ironmaking in China's blast furnaces. However, due to the differences in the reduction properties of H₂ and CO, the softening-melting dripping behavior of sinter in hydrogen-rich blast furnaces is different, which in turn affects the formation of the softening-melting and molten dripping zone in the blast furnace. In this paper, the softening-melting-dripping behavior of sinter under different atmospheres was investigated by controlling the proportion of H₂ in the reducing gas, and the mechanisms driving these changes were elucidated. The results indicate that the softening temperature of the sinter increases and the softening-melting interval becomes wider as the proportion of hydrogen increases from 0 % to 30 %. In addition, after reduction with H₂ instead of CO, the melting and dripping temperatures of the sinter increased significantly, the molten dripping interval narrowed, the ΔPmax of sinter decreased gradually, and the permeability of the sinter burden was improved. Notably, the effect of hydrogen-rich reduction on the FeO content is extremely significant, further affecting the softening, melting, and dripping behavior. The reason is that the high reactivity of hydrogen excessively promotes the reduction of FeO and hinders the generation of low melting point substances in the slag phase.