GB1054783A - - Google Patents

Abstract

1,054,783. Uranium oxides; uranium carbide. MINNESOTA MINING & MANUFACTURING CO. June 25, 1963 [June 25, 1962], No. 25314/63. Heading C1A. [Also in Division G6] Spherical particles of uranium oxide are formed by melting a fusible solvated uranium salt, dispersing it in an inert medium to give particles 10-500Á in diameter, and heating the particles below their melting point, preferably under reduced pressure, to remove the solvating solvent and form uranium oxide. Heating below 450‹ C. gives UO 3 , at 450- 800‹ C. gives U 3 O 8 . and at 800-1800‹ C. in a H 2 furnace gives UO 2 . The uranium salt may be uranyl nitrate, oxalate, perchlorate, sulphate or acetate, as a solvate with water, tributylphosphate, ether, ketones, or esters. In a modification, up to 50% finely divided carbon, e.g. carbon black, is added to the molten mixture and UC or UC 2 is formed by sintering the particles at 1600-2400‹ C. Other materials, e.g. SiC or oxides of Zr, Ca, Nb, Pu, Th, Mn, Al, Be and Ce, or a Th compound, may be dissolved or dispersed in the molten salt. Fusion is carried out under reflux or with addition of solvent; the melt is then dispersed by spraying into a cold inert gas, e.g. air or N 2 , or a liquid such as fluorocarbons, e.g. perfluoro cyclic ethers C 8 F 16 O, or hydrocarbons, e.g. hexane, heptane, kerosene; or by dispersing in a hot inert liquid which is chilled or sprayed. The particles are then screened and sized; those suitable are dried and subsequently heated with stirring or fluidization; unsuitable particles are recycled, after removal of any liquid dispersion med ium.