Effects of Liquidus Temperature and Liquid Amount on the Fluidity of Bonding Phase and Strength of Sinter

Fluidity is one of the important properties of bonding phase in sintering process, because better fluidity is beneficial for improving the strength of sinter. In this work, the effects of liquidus temperature and liquid amount on the fluidity of bonding phase and the strength of sinter were investigated. The experimental results in SiO2–Fe2O3–CaO system indicated that, for both SiO2=5% and SiO2=10%, with increasing Fe2O3 content (decreasing CaO content), the fluidity indices of samples first increased and then decreased. When the liquidus temperature was lower and the liquid amount was more, the fluidity index of SFC sample was higher, and vice versa. The sinter pot experimental results showed that, (1) for the iron ore with SiO2=4.30%, the major phases in the sinter were hematite and SFCA, and the liquid SFCA phase was evenly distributed in sinter. The tumble strength of sinter was higher than 60% in a wider basicity range of 1.8–2.2. (2) For the iron ore with SiO2=12.42%, the olivine was another major phase, and was unevenly distributed in part of sinter. There was a peak value for tumble strength of sinter when the basicity was 2.0. The basicity was higher or lower, the tumble strength sharply decreased. The reasonable basicity of sinter with high-SiO2 content was difficult to determine, and was not proposed to be used in an actual sintering production. The outcomes of the present work may provide guidelines for better understanding the properties of bonding phase and improving the strength of sinter.