Effects of SiO2 on the metallurgical properties and microstructure of sinter

Abstract

In order to provide a theoretical basis for the production of high iron and low silica sinter,the basicity(R) was set to 1.8,1.9 and 2.0,the SiO2 content was variable for each alkalinity,and then 12 groups of ore blending schemes were generated to proceed with sinter pot tests. After that,the influences of SiO2 on the metallurgical properties and microstructure of sinter were researched. The results show that when the SiO2 content increases from 4.8% to 5.7%,the cold intensity gradually increases,and the greatest growing rate is 8%; the sinter reducibility tends to lower,and the decreasing range is from 86.80% to 81.01%; the reduction degradation index(RDI+3.15) gradually increases,and the growing range is from 75.95% to 87.21%. For softening-melting properties,the apparent initial softening temperature(T10) previously increases in the range from 4.8% to 5.4% and then decreases in the range from 5.4% to 5.7%,and the softening range has a widening trend. Selected a alkalinity level R=2.0,when the SiO2 content changes in the range of 4.8% to 5.7%,the microstructure of sinter develops from an ablation shape to a needle-like and columnar shape,the structural uniformity gradually improves,and the main mineral composition changes from hematite to calcium ferrite. Skeletal crystalline hematite,which leads to a low temperature reduction degradation phenomenon,gradually disappears.

Keywords

• ore sintering
• silicon dioxide
• metallurgical properties
• microstructure