Uranium, oxide free metal

For many years the corrosion of uranium has been of major interest in atomic energy programmes. The environments of importance are mainly those which could come into contact with the metal at high temperatures during the malfunction of reactors, viz. water, carbon dioxide, carbon monoxide, air and steam. In all instances the corrosion is favoured by large free energy and heat terms for the formation of uranium oxides. The major use of the metal in reactors cooled by carbon dioxide has resulted in considerable emphasis on the behaviour in this gas and to a lesser extent in carbon monoxide and air. 

A. AMALGAMATED, OXIDE-FREE URANIUM METAL TURNINGS... 

Salt Transport Processing (8, 9, 10, 11) The selective transfer of spent fuel constitutents between liquid metals and/or molten salts is being studied for both thorium-uranium and uranium-plutonium oxide and metal fuels. The chemical basis for the separation is the selective partitioning of actinide and fission-product elements between molten salt and liquid alloy phases as determined by the values of the standard free energy of formation of the chlorides of actinide elements and the fission products. Elements to be partitioned are dissolved in one alloy (the donor... 

Highly charged metal ions (-1-4 to -1-6) hydrolyse water so strongly that in aqueous solution most cannot occur as the free metal ion, but appear as oxo-metal ions where one or two oxide ions are bound to the metal ion. Metal ions that fall into this group include titanium(IV), vanadium(IV), technetium(IV) and polonium(IV) (where the ion is formed) vanadium(V), uranium(V),... 

Calcium metal is an excellent reducing agent for production of the less common metals because of the large free energy of formation of its oxides and hahdes. The following metals have been prepared by the reduction of their oxides or fluorides with calcium hafnium (22), plutonium (23), scandium (24), thorium (25), tungsten (26), uranium (27,28), vanadium (29), yttrium (30), zirconium (22,31), and most of the rare-earth metals (32). 

The problem of electrolytic etching cannot be divorced from that of the prior preparation of the metallic surface. Electropolishing is an absolute prerequisite, not only to avoid any surface cold-work but also to realize a surface as free as possible of insoluble films (oxides or others). The case of uranium bears out the importance of this factor. 

About 10 to 15 per cent of the uranium metal is lost as fines in the washing operations, and this can be recovered free from insoluble oxides and fluorides by elutriation in a simple inverted cone type of elutriator, fed with water from the apex of the cone. The sludge of non-metallic insoluble matter follows the overflow, from which it is settled out and recovered chemically. The metal fines remain in the elutriator, to be removed at intervals, filtered, dried and added to the metal powder product. 

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