| 摘要 |
A uranium aluminium alloy (containing a trace up to 1790 of uranium) is refined to produce fresh uranium aluminium alloy by dissolving the initial alloy in a molten mixture of aluminium halide and alkali-metal halide, wherein the alkali metal halide is present in a quantity very greatly in excess of the aluminium halide which is itself present in approximately stoichiometric quantity with respect to the uranium. A metal phase containing aluminium is separated from a salt phase containing excess alkali-metal halide and an alkali-metal uranium halide. To this salt phase there is then added sufficient aluminium halide to make the molar ratio of Al to alkali metal approximately equal to one, followed by an excess, with respect to the amount stoichiometrically required for the reduction of uranium halide, of metallic aluminium. Uranium metal forms and alloys with the excess aluminium present and this alloy is separated from the salt phase. The temperature of the extractions lies between 600 DEG C. and a 1000 DEG C. with a preferred range of 725 /sB 25 DEG C. The aluminium to alkali metal molar ratio lies in the range 0.1 to 0.5 in the first extraction and becomes 0.8 to 1.2 with a preferred range of 0.8 to 1.0 for the second extraction. The halides used are chlorides and bromides, and both extractions are preferably carried out with the exclusion of oxygen. The process may be used to process irradiated uranium/aluminium nuclear fuel elements (see Group XL (a)). Specification 870,691 is referred to. |
