METHOD OF PRODUCING HIGH PURITY ZIRCONIA POWDER FROM ZIRCON POWDER

摘要

ABSTRACT OF THE DISCLOSUREIn producing zirconia powder by desiliconizingheat treatment of a mixture of zircon powder and apowdery carbon-containing material, optionally withaddition of a zirconia stabilizing oxide such as calciaor yttria, in a non-oxidizing atmosphere, the heattreatment is performed under reduced pressure, viz. at apressure hot higher than 0.7 atm, to thereby efficientlygasify silicon oxide in reduced form. To obtain verypure zirconia powder, adjustment of C/SiO2 mole ratio inthe starting mixture to 0.4-2.0 and oxidation treatmentof the product of the reduced pressure desiliconizingheat treatment are effective. Fluidization of at least aportion of the carbon-containing material at the stageof mixing with zircon powder is also effective fordecreasing residual silica in the product.