The Ternary System Al2O3-CaO-SiO2 – a Comparison of Calculated and Measured Data

In the area of slags phase diagrams, such as ternary systems provide support in pyrometallurgical processes. Low viscosities and liquidus temperatures in addition addition to high reactivities are often required for an economic production. In ternary systems refractory metal components are problematic due to the availability of thermodynamic data of their oxides is barely or incomplete. At pyrometallurgical recycling processes of Al2O3-rich raw materials, the suitable choice of additional charged slag formers like lime is of special interest for decreasing the melting point and the whole energy consumption. Therefore, the application of a hot stage microscope is discussed based on investigated mixtures within the well-known ternary system with the components Al2O3, SiO2 and CaO. Ternary systems, calculated with the software FactSage, represent the reference values for evaluation the measured data. The results of the melting tests show a possible suitability of the hot stage microscope to determine the liquidus area in the three-component system under the consideration of some important facts. On the one hand, an offset of the measured values, obtained by the sample preparation, can be prevented by using isopropanol instead of distilled water. On the other hand, calcareous materials will chemically attack sample carriers made of Alsint. The usage of a platinum basis can solve this problem. © 2012, Springer-Verlag.