Experimental investigation and optimization of the thermodynamic properties and phase diagrams of the CaO-MgO-Al2O3-SiO2-ZrO2 system

English Abstract:

Zirconia-bearing systems are of great importance in geology. The minerals baddeleyite and zircon, for example, are quite useful in geochronology thanks to their refractory nature, capacity to contain trace amounts of uranium and thorium, and occurrence in numerous igneous and metamorphic rocks. Zirconia-bearing compounds are also quite used as refractory materials in the industry. Recently, numerous new thermodynamic property and phase diagram data were published for ZrO₂-containing systems which prompted a re-evaluation of the thermodynamic properties of the ZrO₂ unary system. In this study, new experimental phase diagram data were also collected and a critical evaluation and optimization of the thermodynamic properties and phase diagrams of the CaO-MgO-Al₂O₃-SiO₂-ZrO₂ system was performed. As an example, the optimized ZrO₂-SiO₂ binary system and ZrO₂-CaO-MgO ternary system are shown in Figures 1a and 1b, respectively. The liquid phase was parametrized using the Modified Quasichemical Model while solid solutions were optimized using the Bragg-Williams Random Mixing Model with a polynomial expansion of the excess parameters. The optimized model parameters were incorporated to the oxide database of the FactSage software.