Chelatbildende Austauscherharze,VII

Preparation and use of a resin with 1.8-dihydroxynaphthalene-O,O-diacetic acid as chelating group are described. Besides the separation of many of the common interfering ions it also permits the separation of Hf. The following ions could be separated quantitatively: Mg(II), Pb(II), Cu(II), Fe(III), La(III), Ce(IV), Th(IV), Ti(IV), and U(VI). During these and further qualitative and quantitative experiments no interfering ions could be found. A method for the separation of⁹⁵Zr from its daughter nuclide⁹⁵Nb is also described. The main problem proved to be the separation of Zr(IV) and Hf(IV), owing to their close resemblance. To accomplish quantitative determination of Zr and Hf without any separation,⁹⁵Zr and^175+181Hf radioisotopes were used. The chelating resin permits the separation of 95% of Hf(IV) from an equimolar solution. The main part of Hf(IV) is eluated by 2M hydrochloric acid, and subsequently Zr(IV) by 0.75M oxalic acid. The rest of Hf is enriched in the first fractions of the oxalic acid eluate, so that when eliminating these, even after a single step experiment hafnium free from zirconium and a rather pure fraction of zirconium are obtained. Even under extreme conditions of concentration (Zr∶Hf=91∶1) 75% of Hf can be separated free from Zr in a single step experiment.

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Vorgetragen auf der IUPAC-Tagung in Prag, 1967.