Improvements in or relating to Zirconium Compounds

1,181,794. Zirconium compounds. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. 31 May, 1967 [9 June, 1966], No. 25840/66. Heading C1A. A water-based sol or gel comprises zirconium and nitrate ions in which the nitrate to zirconium molar ratio is between 1À0 : 1 and 1À1 : 1. The sol is prepared by making a dispersion or slurry of zirconium hydroxide or carbonate and reacting this with an approximately equimolar quantity of concentrated HNO3 at 50‹ to 70‹ C. Stabilizers for zirconia may be added as nitrates such as calcium or yttrium nitrate. Drying the sol at 80‹ to 90‹ C. yields a waterdispersible gel. The gel may be denitrated at 500‹ C. and the product calcined at a higher temperature in air to give high density zirconia. The sol suspended in an inert liquid such as trichloroethane may be irreversibly denitrated by a water-insoluble amine such as a tertiary alkyl primary amine.