PROCESS FOR MANUFACTURE OF POWDEROUS SYNTHETIC SILICON DIOXIDE Russian patent published in 1994 - IPC

FIELD: manufacture of extra pure quartz glass used in optical fiber engineering. SUBSTANCE: essence of this process resides in that extra pure powderous synthetic silicon dioxide is produced by hydrolyzing silicon tetrachloride at temperature of minus 65 to minus 45 C with use of granulated ice. Ratio between silicon tetrachloride and water should be SiCl₄ 40 to 45 to H₂O 55 to 60 mol percent. EFFECT: silicon dioxide to be synthesized demands no additional grinding and separation has extra high purity sufficient to manufacture extra pure quartz glass; powderous silicon dioxide SiO₂ is characterized by highly effective density that allows producing quartz glass blocks completely free from blow-holes in commercial quantities. 1 tbl