Influence of SiO2 on the Compressive Strength and Reduction-Melting of Pellets

The effects of SiO2 content on the compressive strength, reduction behavior and melting-dripping properties of the pellets were investigated under experimental conditions. The experimental results indicated that the compressive strength of pellets gradually decreased with increasing SiO2 content, mainly because the pellets with high SiO2 had poor crystallization capacity, a more liquid phase and more pores. With increasing SiO2 content from 2.19 wt% to 8.13 wt%, the reduction degree of pellets descreased due to the generation of 2FeO·SiO2. Based on the morphology analysis, inside of the pellets, 2FeO·SiO2 caused the compact structure and fewer microspores with increasing SiO2 content, which was unfavorable for the reduction process and resulted in the decrease of the reduction degree. Also, increasing the SiO2 content had negative effects on the melting-dripping properties of pellets. The melting-dripping properties can be improved by adding some sinter with high basicity in the mixed burden. The current work established the relation between SiO2 content and reduction-melting behavior of pellets, which can provide theoretical and technical support for the effective utilization of pellets with different SiO2 content in blast furnace process.