Effect of Mineral Elements Migration on Softening–melting Properties of Ti–bearing High Basicity Sinter

Abstract

The mineral elements migration behaviours of Ti–bearing high basicity sinter during softening–melting process, as well as its effect on softening–melting properties, are studied using scanning electron microscope and X–ray diffractometer. We can conclude that both MgO and Al₂O₃ content increase while TiO₂ content increases first and decreases later overall in the slag phase from the original state to melting end. At softening stage, some perovskite dissolves into the slag phase and part of TiO₂ and MgO in wustite phase transfer into the slag phase. The low melting temperature of the slag phase is the main factor for the low softening temperatures of Ti–bearing sinter. At melting stage, TiO₂ in the slag phase is tiny and changes little. The low liquidus temperature and viscosity of the slag phase result in the low melting start temperature of Ti–bearing sinter. The slag phase melts great earlier than metallic iron while the unfused sponge iron still bounds large amounts of perovskite crystals. And then, iron collapses and releases the restrained crystals at a higher temperature, resulting in the second rise of pressure drop.