Thermodynamic modeling of the FeO-BaO-Al2O3 phase diagram

Alkaline earth metals have recently become more and more in demand in the production of steels and alloys and are part of most compositions for refining and modification. In this connection, the need to construct the phase diagrams of the oxide (slag) systems, including alkali-earth metals oxides as components, in particular BaO, increases. This information is necessary both for analyzing the composition of the formed non-metallic inclusions and for understanding the effect of the concentration of alkali-earth metals oxides on the melting point of the slag. As is known, thermodynamic modeling is a key tool for choosing the optimal direction of research in the field of metallurgical technologies, therefore, the calculation of phase diagrams of oxide systems as part of a multicomponent slag melt is an important task for researchers. This is especially true for systems containing BaO as a component, since the data available in the literature are limited only to phase diagrams of binary systems. In this work, the surface of the liquidus of the FeO-BaO-Al2O3 phase diagram was plotted. The theory of subregular ionic solutions was used, the energy parameters of which were obtained in the course of this calculation. We also estimated the temperatures, enthalpies and entropies of formation of barium aluminates Ba3Al2O6, BaAl2O4, BaAl12O19 from the components of the oxide melt. These values for Ba3Al2O6 turned out to be 1604 °C, 159 410 J/mol, 16.215 J/(mol∙K); for BaAl2O4 - 1814 °C, 101 424 J/mol, 7.332 J/(mol∙K); for BaAl12O19 - 1911 °C, 613 406 J/mol, 201.201 J/(mol∙K), respectively. The information obtained was compared with the few available literature data.