Effects of SiO₂ on the metallurgical properties and microstructure of sinter

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.