Influence Of MgO/Al₂O₃ Ratio On Liquid Phase Generation During Iron Ore Sintering

The influence of Mg O/Al2O3 ratio on liquid region projection and liquid generation quantity under different temperature of Ca O-Si O2-Fe OX-Mg O-Al2O3 system was calculated by Fact Sage thermodynamic software. The begining and ending generation temperature of the effective liquid phase of iron ore sintering were tested by high temperature melting speed melting point meter respectively. The mineral phase constitution of different type Al2O3 iron ores were analyzed through equilibrium experiments and XRD diffraction. The specific results are as follows.:1)Within a certain range(Mg O/Al2O3 ratio is 0.5~1.5), with the increase of Mg O/Al2O3 ratio, the liquid phase area of Ca O-Si O2-Fe OX-Mg O-Al2O3 system increased.But when Mg O/Al2O3 ratio is too big, the liquid phase area shift from the iron rich area to Ca O enrichment area, which would be harmful to sintering.2)The studying of influence of Mg O/Al2O3 ratio on liquid generation characteristics showed that the liquid phase generation temperature range increased with the increased Mg O/Al2O3 ratio, and the liquid phase generation reached maximum when the Mg O/Al2O3 was 0.75 for the iron ores containing two types of Al2O3.When Mg O/Al2O3 ratio was in a small range(0.5~0.75), the iron ore ores containing kaolin type Al2O3 had a better sintering curve and liquid phase characteristics.3)Through the XRD diffraction analysis, the main mineral phases had little difference for the two kinds of Al2O3 iron ores. With the increase of Mg O/Al2O3 ratio,magnetite, calcium silicate, calcium ferrite were increased, and the columnar SFCA turned to needlelike SFCA-I for the iron ores containing kaolin type Al2O3; while calcium silicate, calcium ferrite, and other mineral phase content reduced for the iorn ores containing gibbsite type Al2O3.