Evaluation of Interfacial Tension in the Liquid Aluminum Alloy-Liquid Slag System

In the present paper, the results from investigations regarding interfacial tensions present at the borders of a liquid aluminum alloy and two selected melted fluxes (mixtures of salts) are presented. The fluxes feature solidification characteristic curves that are very close to each other as well as differentiated chemical compositions. For the comparative investigations, the so-called surface property index (WS) is calculated for both fluxes with the use of the ion theory of slags. The investigations of the interfacial tensions were conducted on a stand that enabled the measurement of the force values accompanying the tearing-off of the probe from the interfacial surface. A very clear relationship between the interfacial tension values and the WS index values that characterize both fluxes was found. An increase in the WS index value resulted in an increase in the investigated interfacial tension values. It was also found that, in both cases under investigation, an increase in the system temperature value resulted in an increase of the values of the interfacial tensions present within. In the conclusion, we state that the metallurgical treatments (for instance, the recycling of the cast metal composite materials by way of component separation) should be conducted with the use of salt mixtures (fluxes) characterized with WS index and melting temperature values as low as possible.