METHOD FOR PRODUCTION OF PARTICULARLY PURE SYNTHETIC CRISTOBALITE WITH FRACTION OF 74-390 mcm Russian patent published in 2022 - IPC C01B33/12 C03C1/02 

FIELD: optics; light engineering; instrument making.

SUBSTANCE: invention can be used in optics, light engineering, instrument making in the production of cristobalite of particular purity for materials of fiber-optic components. A method for heat processing of powder of synthetic silicon dioxide, obtained by a sol-gel technology, with Li content of up to 1 ppm, includes drying of powder from residual moisture at 150-300°C in a quartz reactor in a rotating furnace with rocking. Then, powder is evenly heated up to 1200°C in an oxygen and nitrogen medium and is processed at high temperatures to transfer powder into cristobalite at a temperature not less than 1300°C for 8 h in an oxygen medium. Upon completion of high-temperature processing, purification is carried out in a mixture of hydrogen chloride and nitrogen for at least 30 min. Powder of particularly pure synthetic cristobalite with a fraction of 74-390 mcm is obtained, having the total content of impurities by Al, Ca, Fe, K, Na, Ti, Li, Mg, Mo, Cd, Mn, Cr, Zn of no more than 0.13 ppm, specific surface of no more than 1 m²/g, bulk density within 1.2-1.3 g/cm³, content of hydroxyl groups of no more than 1 ppm.

EFFECT: inventions allow for reduction in duration of processing of powder in a medium of hydrogen chloride and nitrogen, increase in purity of synthetic cristobalite.

2 cl, 1 tbl