| The generation of liquid phase in sintering process is the basis of consolidation. Themain theories include CaO-FeO-Fe2O3, CaO-Fe2O3-Al2O3, FeO-SiO2, FeO-Fe3O4etc.Recently the main theory about sintering liquid phase is calcium ferrite.The Fe2O3-SiO2-CaO-Al2O3-MgO five component system in iron ore sinteringprocess is studied deeply. in order to predict the reactions may occur and balance state inthe system, thermodynamic calculation on the Fe2O3-SiO2-CaO-Al2O3-MgO fivecomponent system has been carried out, based on metallurgical thermodynamics. Andthen on the condition of quasi chemical equilibrium, The generation of liquid phase inrich Fe area in Fe2O3-SiO2-CaO system were studied in detail. By changing the content ofAl2O3, MgO, reveal the changing regulation of phase composition, the amount of liquidphase, microstructure, the conclusions are as follows:1) According to the thermodynamic calculation， the substances that may generatethrough solid state reactions in the system include:2CaO·SiO2,2MgO·SiO2, MgO·Fe2O3,CaO·Fe2O3,2CaO·Fe2O3,12CaO·7Al2O3.2) On the condition of phase equilibrium, the effect of temperature on thedistribution of magnesium ferrite in crystalline or amorphous phase is little. MgOdiffuses into Fe2O3form the MgO·Fe2O3and tends to be stable. Due to the rapid cooling,calcium ferrite system crystallization is not enough, and has no diffraction peak.3) Increasing temperature, the Fe2O3that enter into the system increase, and liquidphase region expand. The increase of Al2O3content also makes the liquid phase areaexpand. The amount of calcium ferrite also increases.4) In the experimental temperature range, increase the amount of Al2O3promotesthe formation of calcium ferrite minerals system. The increase of MgO content leads tohigh melting point substances form in the system, which will reduce the amount of liquidphase. |
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