Ruthenium in fuel reprocessing by fluoride volatility process, (2)

The following three reactions were studied by thermochromatography in relation to the reprocessing of oxide fuels: (a) fluorination of RuF3 by F2, (b) fluorination of RuO2 by F2, (c) fluorination of RuO2 mixed with an excess of an oxide UO2 or Y2O3. The reaction products were as follows. The RuF3-F2 reaction yields RuF5. Fluorination of RuO2 by F2 results in the production of a mixture of RuF4-RuF5-RuOF4. (RuF5 may be produced by fluorination of RuF4 resulting from decomposition of RuOF4 in the apparatus for thermochromatography). When dried at 1500C prior to fluorination the products of RuO2-F2 reaction in the presence of an excess UO2 on Y2O3 are much more volatile than those obtained in the absence of these oxides. More than 60% is a mixture of RuF6 and RuO4 with a smaller amount of RuOF4, RuF4 and RuF5. When the RuO2-Y2O3 or UO2 are dried at 8000C prior to fluorination, RuO4 and RuF6 are also produced, but the yields is about 10 -- 20%. Results from I.R. measurements are interpreted the same way. (author)