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- Author or Editor: O. Stepanets x
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Abstract
A method based on exchange reactions of metals with coordination compounds and termed displacement extraction chromatography is proposed. The method consists essentially in the successive displacement of elements with lower extraction constants, present in the form of coordination compounds in the organic phase on the column, by substoichiometric amounts of elements with higher extraction constants, admitted to the column in aqueous solution. The method was used to determine various contaminations in yttrium, molybdenum, zirconium, niobium and beryllium by activation analysis.
Abstract
A method of element separation has been worked out with the use of substoichiometric exchange reactions in combination with extraction chromatography. The principle of the method consists in the successive displacement of elements with lower extraction constants from their complexes by a substoichiometric amount of an aqueous solution of a competitive metal with a higher extraction constant. As stationary phase a chloroform solution of zinc diethyldithiocarbamate was used in the column, and a porous polytetrafluoroethylene (Ftoroplast PF-4) was employed as an inert supporting material. The method was used for the radioactivation determination of zinc, copper, cadmium, silver, mercury, managanese, cobalt and iron traces in yttrium, molybdenum, zirconium, niobium and beryllium. When samples weighing 0.1–1 g are irradiated for 20 hrs with a neutron flux of 1.2·1013 n·cm−2·sec−1, the determination sensitivity is 10−4−10−8%.
Abstract
The possibility of substoichiometric displacement in ion association systems of metal halogenide anions (chlorides and iodides) and extraction reagent cations is demonstrated. Tetrephenylarsonium halogenide, ternary amines and quaternary ammonium halogenides were used as extraction reagents. The method was applied to the determination of several impurities in aluminium by activation analysis.
Abstract
Radioactivation analysis is the only method which allows the determination of individual rare earth element impurities in rare earth elements of high purity. The determination of dysprosium, europium, samarium and gadolinium in yttrium oxide is complicated by the short half-life of165Dy (138 min.) and by the difficulty of separating traces of these elements from the matrix. A chromatographic method has been developed, for the separation of traces of Dy, Eu, Sm and Gd from ytrium, on a column packed with anion exchangerAV-17, by means of elution with 0.1N and 0.3M solutions of EDTA-sodium salt, followed by the separation of the mixture of the rare earth impurities on a microcolumn of cation exchangerKU-2, using a 0.17M solution of ammonium α-hydroxyisobutyrate as the eluent. The sensitivity of the determination of Dy, in the case of irradiating 10 mg of Y2O3 with a flux of 1.2·1013 n·cm−2·sec−1 for 5 min. was 1·10−7%; the corresponding values for Sm, Eu and Gd, when irradiating a 100 mg sample of Y2O3 for 20 hours with the same flux, were 2·10−7%, 1·10−8% and 5·10−6%, respectively.
