Tin oxide solubility in soda-lime silicate melts
Résumé
Due to its low solubility in molten glass, the lowest among non-colouring oxides, tin dioxide is commonly used as refractory material, electrodes or as opacifier in enamels. Thus, this work deals with the influence of glass composition and temperature on SnO 2 solubility. The solubility of tin dioxide was first assessed as a function of time and temperature in a standard commercial soda-lime glass. This study showed that dissolution equilibrium could be reached in short time (2h). Moreover, long lasting and high temperature heat treatments led to sodium volatilisation, which lowered SnO 2 solubility limit. An Arrhenius dependence of solubility with temperature, describing a single dissolution mechanism, has been observed in the temperature range 1200-1400°C. The influence of Na 2 O content on SnO 2 solubility limit suggested the consideration of glass basicity. A similar study has been performed in simple ternary glasses (Na 2 O-CaO-xSiO 2) and in commercial glass enriched with Na 2 O, CaO or Al 2 O 3. From the first results, basicity seems to be a complex parameter. The specific role of these latter oxides in the physico-chemistry of molten soda-lime glasses is discussed here, regarding the polymerisation degree of the glass network or the precipitation of new phases.
Domaines
Chimie inorganique
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