| 摘要 |
864,576. Refining uranium; crucibles. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. April 11, 1945 [April 28, 1944], No. 9034/45. Class 82(1) [Also in Groups XI and XXII] Uranium metal is refined by supporting a mass of the metal on a strainer, heating the mass under reduced pressure, preferably not exceeding 10 microns, to cause the uranium to melt and flow through the strainer, condensing any vaporized impurities on a surface adjacent the uranium, collecting unvaporized impurities on the strainer and collecting the purified uranium in an inert atmosphere. The operation may be carried out in the apparatus shown in the Figure, the impure uranium 1 being supported on strainer 2 in a crucible 3 which is mounted on a mould 4. These parts may be made of beryllia or thoria or of carbon, graphite, silicon carbide or alumina lined with beryllia or thoria. The mould rests on a tungsten block 6 and support 7. The whole is contained in envelope 11 of refractory glass. Vertically adjustable induction coil 12 is first lowered to heat the block 6 above the melting point of uranium, then raised to the position shown to heat the uranium. A tungsten coil 15 is heated by induction and in turn heats the uranium by conduction through the crucible, heat loss being minimized by radiation shield 9 and cover 10. Vaporized impurities are condensed on the surface of envelope 11 which may be cooled by fan 13. Vacuum is maintained through tube 17 and the uranium cast in mould 4 is cooled to room temperature in an inert gas atmosphere admitted through tube 18.
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