Аннотация:The work is aimed at determining the solubilityof water in fluorine-containing quartz-normativealuminosilicate melts. Experiments were carried out at800°C and 1 kbar with different initial contents of water (3, 5, 7 wt. %) and fluorine (0, 4, 8 wt. %) in the system and a constant Si/Al/Na/Li ratio close to the composition of deeply differentiated topaz-bearing granites. The experimental products are represented by transparent porous aluminosilicate glass. IR and Raman spectroscopy were used to estimate the water content in the aluminosilicate glass. According to the IR spectroscopy data, three main regions are distinguished: the region of 1400-1800 cm-1, which corresponds to vibrations of bonds of surface-adsorbed molecular H2O on the surface of aluminosilicate glass; the region of 3450-3800 cm-1, responsible for surface-absorbed water, with the addition of asymmetric vibrations of OH-groups and the region of 3200-3450 cm-1, in which 3 characteristic absorption ranges were found (3212-3275 cm-1, 3338-3383 cm-1, 3411-3438 cm-1). It is assumed that the manifestation of these 3 ranges is due to the fact that the hydroxyl group was chemisorbed into the structure of aluminosilicateglass, or that it was able to occupy an existing vacancy in the crystal structure of the glass. According to the Raman spectroscopy data, almost all the spectra of the samples we obtained are in the range of Raman shift values from 600 to 4000 cm-1. Vibrations of the bond of silicon (or aluminum) with oxygen are reflected in the spectrum in the range of 700-1280 cm-1. The oscillations of the O-H and H2O bonds are reflected in the range of 2800-3720cm-1. In the absence of fluorine in the system, the amount of water dissolved in the melt does not exceed 2,4 wt. %. With an initial fluorine content of 7-8 wt. %, the amount of dissolved water increases to 6-7 wt. %. In the conducted series of experiments, the appearance of a fluid phase was not recorded. A further increase in the initial water contentin the system can lead to an increase in the concentration of water in the melt.
