Method of polishing glass ware with sulfuric acid and hydrofluoric acid

Abstract

The invention relates to a polishing method for pressed glass or ground glass articles. As is conventional, polishing is effected in a bath containing sulfuric acid and hydrofluoric acid. Rinsing with a sulfuric acid and/or water washing bath intervenes and follows the polishing process. According to the method of the invention, the sodium and/or potassium ions resulting from the dissolution of glass constituents are removed from the polishing bath by the following means: (a) by adding fluorosilicic acid to the polishing bath, precipitating the corresponding silicofluorides and filtering off the solid matter, (b) by electrolysis in a mercury cell with the formation of sodium- and/or potassium amalgam, (c) by electrolysis in a cell having a cation semi-permeable membrane or (d) with the aid of cation exchangers.

Dependencies are inferred from the claim text.