Nixon & Vanderhye
Method for preparing zircon powder
 A method for preparing zircon powder, which comprises mixing (1) silica sol and (2) an aqueous zirconium oxychloride solution having a concentration which would be from 0.1 to 2 mols/l after mixed with the silica sol, in a SiO.sub.2 /ZrO.sub.2 molar ratio of from 0.95 to 1.10, heating the mixture to hydrolyze the zirconium oxychloride, followed by dehydration treatment to obtain a powder, heating the powder from room temperature to a calcination temperature over a period of from 0.7 to 30 hours and calcining the powder at a temperature of from 1,200.degree. to 1,400.degree. C. for a period of time satisfying the relation of: EQU t.gtoreq.116-0.08T where t is the calcination time (hr) and T is the calcination temperature (.degree.C.), or heating the powder from room temperature to a calcination temperature over a period of from 0.8 to 70 hours and calcining the powder at a temperature higher than 1,400.degree. C. and not higher than 1,700.degree. C. for a period of time satisfying the relation of: EQU t.gtoreq.18-0.01T where t is the calcination time (hr) and T is the calcination temperature (.degree.C.). 
Tosoh Corporation
C
C01B
inventional
Hiroshi Naoki Hirokuni Toshiyuki
Yamamura Kosugi Hoshino Mori