Thermodynamic studies of some iron oxide-containing slag systems

Sammanfattning: In the present investigation experimental measurements ofthe thermodynamic activities of iron oxide in the systems:Al2O3-“FeO”, CaO-“FeO”,“FeO”-SiO2 and, CaO-“FeO”-SiO2 wereperformed by using gas equilibration technique. Theexperimental measurements were performed in the temperaturerange 1823-1923 K for the binary systems and, at 1873 K for theternary system respectively. The molten slag, kept in aPt-crucible was brought to equilibrium with a Ar-CO-CO2 gasmixture. A part of the Fe from the”FeO”was reducedand the metal formed dissolved in the Pt phase. The sampleswere quenched after the required equilibration time and theslag phase as well as the platinum crucible were subjected tochemical analysis. The activities of”FeO”in theslag were calculated from the experimental data usingthermodynamic information on the Fe-Pt binary metallic system.The thermodynamic activities of iron in iron-platinum solidalloys were measured by the solid electrolyte galvanic cellmethod in the temperature range 1073–1273 K. Sixdifferent Fe-Pt alloys covering the entire composition rangewere studied. The results were fitted into a regular solutiondescription in order to extrapolate the activities of thedissolved iron to the experimental temperatures for the slagmeasurements. The experimental results are discussed on thebasis of the earlier work.Keywords:Thermodynamics, activities, slags,iron-platinum alloys, solid electrolytes, galvanic cell, gasequilibration technique.