Abstract

Sintering process is a commonly used pre-treatment process for iron containing burden materials with an aim to produce porous, agglomerated sinter material with suitable properties to be charged into the blast furnace. During the sintering process the material undergoes a series of reactions, during which the conditions vary considerably. These changes in temperature and state of oxidation cause changes in the mineralogical composition of the material and although the sintering process does not completely reach the chemical equilibrium, it is important to understand the phase equilibria of the sinter system in order to analyse and control the effect of various factors on the sintering process. The purpose of this paper is to give a review on the research related to phase equilibria in iron ore sinters. The main components of the sinter are FeO, Fe₂O₃, SiO₂, CaO, Al₂O₃ and MgO and by studying the phase equilibria of this system, the behaviour of sinters can be evaluated. Based on the experimental data, oxide databases have been created to provide thermochemical data of all the necessary compounds within this system. Concerning the solutions, more research is required related to SFCA phases. These databases are commercially available with thermochemistry software and can be used to compute phase diagrams illustrating the effect of different factors on the phase equilibria within the FeO–Fe₂O₃–SiO₂–CaO–Al₂O₃–MgO system. Phase diagrams provide a useful tool to study the behaviour of the material in both sintering process itself as well as in the following reduction processes such as the blast furnace.