The Homogeneity of Glass Melted in Pots on the Commercial Scale

JSGT_1927_V11_T407_T415

The substances which comprise the batch mixture for the purpose of melting glasses usually vary in grain size, in specific gravity, and in melting point. The extent of these differences varies with the type of glass, but, very broadly, the two extremes, so far as commercial glasses are concerned, may be represented on the one hand by those employed for preparing soda–lime–silica glasses and on the other by those in which lead oxide is an important constituent, whether for the production of electric bulbs, table glassware, or optical glass; for whereas in the first type we have to deal with substances of distinctly different decomposition temperatures and melting points, as well as some differences of grain size, the specific gravities are not widely different, but in the second, there is also a considerable difference of specific gravity.

G. A. Green & W. E. S. Turner