PROCESS FOR MANUFACTURING GLASS

摘要

Process comprises the following steps: (1) uniformly preheating a silicon dioxide powder containing a phase conversion promoter to approx. 800 deg.C. (2) placing this preheated powder in a vessel while maintaining this high temp., (3) reheating to obtain a sintered moulding having a cristobatile crystal phase, (4) heat-melting the moulding in vacuuo to effect vitrification. During step (1) the silicon dioxide powder is stirred. In step (3) reheating is carried out for a certain time at a temp. just below the sintering temp.