KINETICS OF MUSCOVITE DEHYDROXYLATION IN MICA-GLASS COMPOSITIONS. T.I.Shishelova, L. V.Chilikanova, T.I.Sozinova, A.V.Shcherbakov, Irkutsk Technical University, Irkutsk, Russia

The kinetic aspect of muscovite hydroxylation in a softened glass medium is of primary importance in the formation of optimal technological conditions of production of mica-glass compositions. Kinetic studies of the phases formed in the process of muscovite-glass sintering were carried out by x-ray diffraction and UV spectroscopy. Heating of the mica-glass composition leads to the dehydroxylation of muscovite with the release of molecular water and the formation of sanidine and sillimanite. The rate of dehydroxylation and formation of these phases depends on muscovite size, glass composition, and temperature. The dehydroxylation of muscovite occurs at a temperature lower than that of the formation of sanidine and sillimanite, especially, in the presence of glass. Therefore, their appearance in the sintering products at) 1100 K should be considered as a result of the interaction of the glass with mica dehydroxylate rather than with the initial mica. The dehydroxylate formed seems to be a supersaturated solid solution relative to sanidine and aluminum oxide isolated as independent phases. Aluminum oxide can either occur in an amorphous form or react fast with alumoborosilicate glass components to form sillimanite.