Determination of silica in glasses,ceramics and refractories

A rapid method for the determination of silica in glasses, glass ceramics and refractories is described. The utilization of direct coulometric titration of the excess of 8-quinolinol employed to precipitate the silico-12-molybdate complex, enables duplicate determinations in the presence of diverse ions to be completed in about 3h. Studies of the optimum, conditions indicated that the acidity and choice of acid were critical. For greatest versatility a sulfuric acid medium was better than hydrochloric or perchloric acids. The addition of glycerol allowed analysis of titanium-containing refractories. The accuracy of the method for a wide variety of materials is similar to that of the conventional acid-dehydration method.