Study of Bubbles Elimination in Silica Glass Produced by Flame Fusion from Brazilian Natural Quartz Powder

Silica glass is a fundamental material for the high technology industry due to its physical properties. This material is widely used in the semiconductor, chemical and optical industry. For applications in the optical industry and special lamps, it is necessary that the silica has a reduced content of bubbles and high optical transmittance in the wavelength regions of visible and medium ultraviolet (200 nm – 300 nm). Silica glass samples were produced by the flame fusion Verneuil Method of Brazilian commercial natural quartz powder and imported high purity commercial powder. An acid leaching procedure of the national quartz powder was introduced before the fusion in order to decrease bubbles concentration. The results were compared with the silica glass produced with imported quartz powder and a commercial silica glass used for the fabrication of special lamps, showing an excellent feasibility of application of Brazilian natural quartz to produce high value added silica glass.