Method of producing high purity zirconia powder from zircon powder

Abstract From the Canadian patent

In producing zirconia powder by desiliconizing heat treatment of a mixture of zircon powder and a powdery carbon-containing material, optionally with addition of a zirconia stabilizing oxide such as calcia or yttria, in a non-oxidizing atmosphere the heat, treatment is performed under reduced pressure viz. at a, pressure hot higher than 0.7 atm to thereby efficiently, gasify silicon oxide in reduced form. To obtain very pure zirconia powder, adjustment of C/SiO2 mole ratio in the starting mixture to 0.4-2.0 and oxidation treatment of the product of the reduced pressure desiliconizing heat treatment are effective. Fluidization of at least a portion of the carbon-containing material at the …