Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Energy, Environment Protection, Nuclear Power Engineering
Abstract A systematic study of separating the actinides from each other in 1 M hydrochloric acid media has been carried out using selective oxidation/reduction processes followed by coprecipitation with neodymium fluoride. We have optimized two such procedures, one with bromate and another with permanganate, for the sequential separation of Am, Pu, Np, and U isotopes. The first procedure involves oxidation of Pu, Np, and U to +6 state in 1 M HCl media at 85° C with 30% NaBrO3 and separation from trivalent Am by collecting the latter on the first NdF3 coprecipitated source. Plutonium is then reduced and converted to +4 oxidation state with 40% NaNO2 at 85°C, while Np and U are kept oxidized with additional bromate in 50–70°C hot solution, thus separating Pu by collection on a second NdF3 source. At this stage, Np present in the filtrate is reduced with hydroxylamine hydrochloride and separated from U by collecting on a third source. Subsequently, U is reduced with 30% TiCl3 and co-precipitated on a final source. The second procedure, which employs KMnO4 in 1 M HCl media at 60–85°C for oxidizing Pu, Np, and U, and separating from Am, produced MnO2 which is collected along with Am on the coprecipitated NdF3. This MnO2 is dissolved on the filter itself with 1 mL of acidified 1.5% H2O2 without any degradation of the α-spectra. After evaporating the filtrate to destroy H2O2, Pu, Np, and U are separated by following steps similar to those in the bromate procedure. The recoveries of the actinides with both procedurés are 〉99%. The decontamination factors are between 103 and 104. The precision and accuracy of measurements, as expressed by the relative standard deviation of replicate analyses, are within 5%. Absolute detection limits for a one-day count on a 600 mm2 detector at 32% counting efficiency and 450 mm2 detector at 27% counting efficiency are about 2.7×10−4 and 3.2×10−4 Bq, respectively. These procedures have been applied to the analysis of actinides in environmental samples.
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