Effect of Silica Content on Iron Ore Sintering

Abstract

During the iron ore sintering process, its SiO2 content considerably affects the sinter quality. In this study, the effect of SiO2 content on iron ore sintering indexes was studied, with mineral composition and microstructure analyses. It was shown that the strength and reducibility of sintering products improved when SiO2 content increased. The sinter yield and tumbler index increased from 69.57% and 58.67% to 74.02% and 62.32%, respectively, with SiO2 content increasing from 3.92% to 5.12%. Moreover, the reduction disintegration index (RDI+3.15) increased from 66.50% to 68.28%. There was a quadratic function relationship between SiO2 content (x) and RDI+3.15 (y): y = −0.4841x2 + 5.8932x + 50.8189. Maintaining the SiO2 content in the range of 4.52% to 5.12% would promote the formation of compound calcium ferrite (SFCA) and silicate as the main binding phase which determined the quality of sintering products.