INFLUENCE OF DIFFERENT AL2O3-CONTAINING BATCH MATERIALS ON MELTING, FINING AND PROPERTIES OF SODA LIME SILICA GLASS

Proceeding from the composition (in wt%): 72.5 SiO2, 1.5 Al2O3, 10.5 C aO, 2.5 MgO, 12.5 Na2O, and 0.5 K2O the hatch raw materials calcined a nd hydrated alumina, nepheline syenite, Calumite, and Ecomelt, respect ively, were employed in order to introduce aluminum oxide to the glass . Batch calculations assured constant chemical composition, sand/sulfa te ratios, sulfate;carbon ratios, redox numbers, and total sulfur cont ents. The glasses and melts obtained were investigated with respect to different properties, e. g. viscosity, homogeneity, optical transmiss ion, and residual sulfur content. The results display similarities, ho wever, partly also significant differences with respect to the Al2O3 s ource used. Thus especially the glasses containing the blast furnace s lags revealed distinct characteristics compared to glasses with nephel ine syenite and hydrated alumina. With increasing melting time the dif ferences are reduced.