| 摘要 |
<p>A uranium or plutonium mass is dissolved by adding an alkali metal-aluminium double chloride and heating to 260-800 DEG C. When the mass treated is a spent uranium fuel from a nuclear reactor, plutonium and fission products are separated by adding aluminium metal (if not already present), to form two phases, a metal phase containing uranium and a salt phase containing plutonium chloride and fission product chlorides. The fuel treated may be an oxidic mass or a uranium-aluminium alloy. The process may be carried out in quartz, platinum, or tungsten crucibles in the presence of air, or, in order to prevent the formation of aluminium oxide, an inert gas containing a carbon halide may be passed through the melt; nitrogen, argon, and helium are suitable inert gases, and carbon tetrachloride, carbon tetrabromide, and carbonyl chloride suitable carbon halides. To separate the two phases, the mass may be partially cooled and the molten salt phase removed from the solidified metal. Plutonium is recovered by dissolving the salt phase in acid, followed by solvent extraction or precipitation; alternatively, plutonium metal is obtained by reducing the salt phase with metallic calcium and/or magnesium. Examples describe the dissolution of uranium oxides, plutonium oxide, uranyl chloride, and uranium metal in potassium-aluminium chloride. Other examples show that plutonium, thorium, and cerium go into the soft phase when aluminium metal is present.</p> |
