FUNDAMENTAL STUDY OF HIGH Al_2O_3 SINTER SOFTENING AND MELTING BEHAVIOR

摘要

To elucidate the influence of high Al_2O_3 content on sinter softening and melting behavior, heating-up reduction test under load was carried out. In addition, microstructure study of sinter bed structure change at a different temperature was also made and the mechanism that the effect of Al_2O_3 content on sinter softening and melting property was discovered. SEM results showed that the increase of Al_2O_3 content favored the formation of Al_2O_3-rich slag phase, such as the eutectic (2CaO·SiO_2-2CaO·Al_2O_3·SiO_2-FeO) and gehlenite (2CaO·Al_2O_3·SiO_2), resulting in the decrease of sinter Ts temperature. Further, high Al_2O_3 content improved the concentration of metallic iron and lowered the dripping temperature due to the decrease of slag liquidus temperature and viscosity. At a fixed basicity, it was indicated that there was a relationship between Al_2O_3 content and sinter softening-melting property. Based on the results, counter strategies to cope with the adverse effect of high Al_2O_3 content on the cohesive zone property were also proposed. It could provide guidance for the blast furnace operation of sinter with high Al_2O_3 content.