PRODUCTION OF SYNTHETIC QUARTZ

摘要

PROBLEM TO BE SOLVED: To industrially advantageously produce high purity and high quality synthetic quartz powder by mixing a silicon alkoxide with water, crushing and drying the resultant gel and carrying out treatment in an atmosphere of gaseous ozone and firing. SOLUTION: A silicon alkoxide is mixed with water or a water-alcohol mixture in a molar ratio of 1:3 to 1:20 and the resultant mixture is allowed to react to form gel. This gel is aged at >=40 deg.C for <=1 hr, crushed to about 10μm to 5 mm with a suitable crusher, dried at <=300 deg.C and treated by contact with ozone in a solid-vapor contact device such as a kiln, a fluidized bed, a moving bed or a shelf type contact unit in an atmosphere of gaseous ozone having 3-100 g/m<3> concn. at 100-300 deg.C. The ozone treated gel is heated to 1,000-1,300 deg.C at 10-2,000 deg.C/hr rate in dry air and fired by holding at the temp. until the amt. of residual silanol is reduced to <=500 ppm to obtain the objective synthetic quartz powder.