| 摘要 |
1536239 Uranium dioxide WESTINGHOUSE ELECTRIC CORP 14 June 1977 [14 June 1976] 24822/77 Heading C1A Ceramic grade UO 2 powder having a low residual fluoride content is made by introducing a mixture of UF 6 and steam in the proportion of 2-8 moles steam per mole of U into a first fluidized bed reactor in which a temperature of 475-600‹ C. is maintained, conveying the solid intermediate reaction products (UO 2 F 2 , U 3 O 8 ) to a second fluidized bed reactor in which the mole fraction of HF is controlled to be below 0À7 so as to minimize the formation of UF 4 by introducing into the bed additional steam and H 2 in the proportion of 4-12 moles and 1-6 moles respectively per mole of U while the second bed is maintained at 575-675‹ C., conveying the second intermediate reaction product which includes UO 2 to a third fluidized bed into which 2-11 moles steam and 0.5-6 moles hydrogen per mole U are introduced while a temperature of 575- 675‹ C. is maintained and conveying the third intermediate product which consists essentially of UO 2 having a low residual fluoride content to a fourth fluidized bed into which a heated mixture of air and N 2 is introduced to further reduce the fluoride content and increase the O : U ratio to 2.2-2.3. |
