HIGH-PURITY PYROGENICALLY PREPARED SILICON DIOXIDE

摘要

High-purity pyrogenically prepared silicon dioxide having metal contents of less than 0.2 mug/g is prepared by reacting a silicon tetrachloride having a metal content of less than 30 ppb by means of flame hydrolysis. The silicon dioxide can be utilised for the manufacture of high-purity glasses by means of the sol-gel process, which show a high-homogenity. It can be used for the production of shaped articles, which can be used as preforms for the optical fiber spinning.