METHOD FOR PRODUCING SILICA PARTICLES, SYNTHETIC QUARTZ POWDER AND SYNTHETIC QUARTZ GLASS

摘要

A hydrous silica gel is dehydrated by freezing, thawing, and removing water separated by thawing, thereby yielding silica particles. In addition, the silica particles thus formed is washed and fired, thereby producing a synthetic quartz glass power. A water glass is dealkalized, an oxidizing agent and an acid are added, the mixture thus formed is passed through a hydrogen type cation exchange resin, the aqueous silica ,solution thus formed is then gelled, and the gelled material is then washed and fired, thereby producing a synthetic quartz powder. Silica is sequentially held for a predetermined time at each temperature range of 150 to 400 DEG C, 500 to 700 DEG C, and 1,100 to 1,300 DEG C, thereby producing a quartz glass.