Distribution of fission products in the homogeneous liquid-liquid extraction of uranium.

摘要

The radioactive products from uranium fission constitute a serious health hazard due to the possibility of entry into the food chain and uptake by humans. The processing of spent uranium fuels and the separation of uranium from the fission products and their subsequent safe storage is of great concern to the nuclear industry.;Separation of uranium from fission products by homogeneous liquid-liquid extraction of uranium from one molar nitric acid solution with addition of ferric nitrate as salting-out reagent, into propylene carbonate has been performed. Uranium(VI) was quantitatively extracted into propylene carbonate from an aqueous medium of 0.5 g/l Fe(NO;Precipitation of ferric hydroxide from the initial aqueous phase after extraction of uranium, and also from the aqueous sodium carbonate phase after stripping uranium from the propylene carbonate phase affords efficient decontamination from significant fission products.;The representative fission product elements, molybdenum, strontium, ruthenium, zirconium, and cerium, remained in the aqueous solution after extracting uranium(VI) into propylene carbonate to an extent grater than 97%; i.e., less than three percent of the respective elements were found in the carbonate stripping solution. After the final separation step, the extraction of uranyl ion into propylene carbonate containing dibenzoyl methane, these fission product elements were no longer detectable. Ten percent of the original concentration of iodide was found in the carbonate stripping solution. However, it was removed in the final separation step.;This uranium extraction method can be applied as a practical method for separating uranium from fission products to recover the uranium from spent fuel elements. The capacity of ferric hydroxide for adsorption of fission products and the ability to convert to the somewhat refractory ferric oxide also promises convenience for long term storage.