Preparation of U(VI) and Th(IV) α-sources from calcium nitrate solutions by combining solvent extraction and electrodeposition procedures

Abstract

Summary A simple method of preparing α-sources for alpha spectrometric analysis of uranium and thorium is investigated by combining solvent extraction and electrodeposition procedures. Extraction of these actinides is performed by diethyl ether from calcium nitrate solution with various nitric acid concentrations. Recoveries of 90–100% are obtained for uranium and 83.5% for thorium. Good resolutions are also achieved under optimum conditions. The dependence of the overall yield of U(VI) and Th(IV) is examined in relation to the aqueous phase acidity. A procedure combining solvent extraction and electrodeposition is proposed for a selective α-source preparation of U(VI) and Th(IV). Uranium is first extracted at pH range about 1 to 2. At this acidity, thorium remains in the aqueous phase and may be subsequently extracted from this after acidification with 2 M HNO3. A second decontamination of a specific nuclide is achieved by a selective electrodeposition using electrolyte consisting of about 70% ethanol, 0.45 M hydrochloric acid, 0.09 M acetic acid and 108 µg Fe2O3, with concentrations above 0.48 M in HCl for U(VI) or 0.06 to 0.09 M in HNO3 for Th(IV).