MELTING METHOD OF QUARTZ GLASS Russian patent published in 2020 - IPC C03B20/00 

FIELD: technological processes.

SUBSTANCE: invention relates to a method for crucible, vacuum-compression smelting of high-purity ingots of quartz glass with low internal friction due to high structural perfection of glass volume. According to method bulb with grits is filled with especially pure oxygen, heated at temperature of 1,400 °C, then cooled below 50 °C, is evacuated to 10^-4 Pa, bulb with high-purity grit under vacuum is ampulated, the ampoule is wrapped with coal-graphite cloth in 1-2 layers, inserted into the graphite crucible installed in the high-frequency vacuum-compression melting furnace inductor, which chamber is first evacuated to 10^-2–10^-3 Pa, then filled with gas mixture of argon and helium to pressure (1–2)⋅10⁴ Pa, ampoule with grits melts at temperature 1,800 °C, preset time is held at this temperature, glass melt is homogenized, at final stage melt is compressed with gas mixture of argon and helium at pressure (1.5–2) MPa, then furnace thermal unit temperature is reduced to 1,650 °C, the gas mixture is removed, the temperature in the thermal assembly decreases at rate of (5±2) °C/min up to 1,200 °C, further, the furnace heater is switched off and the glass ingot with an arbitrary speed is cooled below 50 °C, residual gas mixture is pumped from melting chamber, chamber is filled with atmospheric air, crucible with quartz glass ingot is removed from furnace.

EFFECT: technical result consists in melting ingot of quartz glass of high chemical purity, with low absorption of optical radiation from infrared to ultraviolet wavelength of light, homogeneous and perfect.

1 cl