Ceramics-Silikáty 52 (2) 66-71 (2008)

DETERMINATION OF GAS PROPERTIERS IN GLASS MELTS

J. Kloužek, L. Němec, M. Arkosiová, M. Jebavá, V. Tonarová

The paper summarizes experimental methods of measurement of gas properties needed for the description of the interactions gas - glass melt. The combination of the melt extraction, gas chromatography, electrochemical methods and visual observation of bubble behaviour or absorption of the defined volume of gas in the melt is used for the determination of diffusion coefficients, actual concentrations and solubilities in the melts. In addition, the gas chromatography and mass spectrometry are used for the analysis of gases evolved during heating of glass batch making possible to study important reactions in early stadium of the melting process. Equilibrium constants of redox reactions are measured by indirect method when combining electrochemical measurement of oxygen equilibrium partial pressure and chemical analysis of redox species in quenched samples. The gas properties in glassmelts may be simultaneously obtained by the observation of growth or dissolution of defined bubbles and by their subsequent analysis. The evaluation procedure comes from equations of bubble behavior. One gas pro-perty, either physical solubility or actual concentration in the melt should be however ensured by above described method. To examine only the rate of the refining process, the values of the bubble growth rates are measured and subsequently used in the simplified mathematical model.

Keywords: Gases, Glass, Diffusion coefficient, Solubility