Sulfate Decomposition And Sodium Oxide Activity In Soda-Lime-Silica Glass Melts

Reaction equilibrium constants for the sulfate decomposition process, which releases oxygen and sulfur oxide gas in soda-lime-silica glass melts, have been determined. The chemical solubility of SO2, probably in the form of sulfite ions in soda-lime-silica melts, has also been determined. The chemical solubility value of SO2, dissolving as sulfite, ranges between 0.02 and 0.06st% SO3 at 1 bar SO2 pressure in the temperature range of 1600-1800K. Results of square-wave-votammetry studies and measurements of the temperature-dependent sulfur retention after the fining process of commercial float glass melts and a model soda-lime-silica melt, with 74 wt% SiO2, 16 wt% Na20, and 10 wt% CaO, are presented.