PRODUCTION OF STABILIZED AND NONSTABILIZED ZRO2 BY CARBOTHERMIC REDUCTION OF ZRSIO4

The kinetics of reduction of zircon by carbon have been investigated i n the temperature range 1400-1650-degrees-C. Volatilization of SiO per mits production of zirconia of about 96% purity direct from zircon wit h 100% removal of the silicon content being achieved in less than 2 h at 1650-degrees-C. Addition of MgO, Y2O3 or CaO stabilizers to zircon prior to the reduction permits direct production of partially stabiliz ed zirconia from zircon by means of carbothermic reduction. The presen ce of such stabilizers has been found to produce a slight increase in the reduction of kinetics of zircon.