Extraction of radiostrontium from the mixture of radionuclides in milk using dicarbolide of cobalt

The possibilities of radiostrontium extraction from milk after the isolation of radiocesium were investigated. The polyhedral complex of the type H+[(π-/3/-1,2-C2B9H11)2Co-], further referred to as dicarbolide-H+, in nitrobenzene was used for the extraction. The increase of values and larger differentiation of distribution ratios in the extraction of ion associates of radionuclides were achieved by hydrophobizing with polyethyleneglycol (PEG). The changes in the distribution ratios of 90Sr, 89Sr and 90Y with PEG concentration were studied, and ranges of the highest synergic effect, changing with different extraction agent concentrations in extraction from water solutions and a fresh milk were determined. The influence of milk dilution and nitric acid concentration upon the value of distribution ratio in radiostrontium extraction using dicarbolide-H+ and the optimum PEG concentration were investigated. Under suitably selected conditions of radiostrontium isolation, the distribution ratios of some potential contaminants were determined. The influence of nonisotopic carrier Ca2+ upon radiostrontium extraction was examined. The possibilities of purification of isolated radiostrontium using reextraction were investigated. A selective and quick analytical procedure was suggested for radiostrontium isolation after the separation of radiocesium from a mixture of fission and activated radionuclides in milk using extraction by dicarbolide-H+. The chemical yield is about 98% and 90Sr is determined by liquid scintillation technique. (author)