Reologiske og termodynamiske egenskaber af høj aluminiumsilikat smelter / Rheological and thermodynamic properties of high aluminosilicate melts

The research work establishes a relation between rheological and thermodynamic properties for aluminosilicate compositions and links the properties with the melt structure. The knowledge can be implemented in the commercial glass and fibre production and can also contribute to the scientific modelling of igneous and volcanic processes. Investigation of multicomponent silicate systems results in a large number of variables, for which it is difficult to control the effect of each single one. Thus the investigated system is simplified to only three components: CaO, Al2O3 and SiO2 denoted as CAS. The investigation consists of measuring the high and low viscosity behaviour as function of temperature, the glass transition temperature, the thermal expansion coefficient and the heat capacity and evaluation of fragility and configurational entropy. The experiments were carried out at Institute for Mineralogy, Petrology and Geochemistry (IMPG) at Ludvig Maximillian University, Munich, Germany as well as at the laboratory at Department of Production. Furthermore, the non-Newtonian behaviour of aluminosilicate melts at high temperature is investigated. During an industrial fibre drawing process silicate melts are exposed to a very high deformation rate, which might be high enough to lead to a non-Newtonian behaviour of the melt and directly influence the drawing process. The investigation included both design and development of laboratory equipment followed by laboratory experiments. The capillary method is used for the design of the equipment. (Mette Solvang)