| 摘要 |
PURPOSE:To efficiently transfer and remove impurities in a molded article and to obtain the molded article of high-purity quartz glass free from devitrification, by heating the molded article of quartz glass held between a positive and a negative electrodes in a furnace under control, impressing a DC electric source to the electrode in an inert gas atmosphere and electrolyzing. CONSTITUTION:A positive electrode 8 having an electrode plate 10 held by a supporting pipe 12 equipped with an inert gas introducing pipe 13 in a furnace 1 which is provided with heating elements 2 and 3, measures temperature by a temperature measuring means 5 equipped with a thermocouple 6 in a protecting pipe 7 and can control the temperature by a temperature regulating means 4 is opposingly set to a negative electrode 9 having an electrode plate 11 at a facing position thereof and a molded article (e.g. core pipe or crucible for pulling up single crystal) 16 of quartz glass is held between the electrodes. Then an inert gas is introduced through a feeding means 14 and a flow velocity setting means 14a from an introducing pipe 13 to the furnace 1, the molded article 16 is heated while controlling at >=1,000 deg.C, an electric current 15 is sent through a DC current source between both the electrodes 8 and 9, the molded article 16 is electrolyzed, impurities are efficiently transferred and removed to give the high-purity molded article 16. |
