Separation of no-carrier-added <Superscript>149</Superscript>Gd from <Superscript>12</Superscript>C activated natural praseodymium matrix

¹⁴⁹Gd was produced from the ¹²C induced reaction on natural praseodymium target. No-carrier-added (nca) ¹⁴⁹Gd was separated from the bulk target matrix by liquid–liquid extraction (LLX) using cation exchanger di-(2-ethylhexyl)phosphoric acid (HDEHP) dissolved in cyclohexane. High separation factor of 2,450 was achieved at the optimal experimental condition when 1% HDEHP and 0.1 M HCl were used as organic and aqueous phases respectively. The result was also compared with the previous reports.     

Behavior of neptunium in the separation process of actinides from irradiated targets

Radiochemical separations of trace amounts of actinides produced in heavy ion reactions with actinide targets are described. The neptunium behavior in the separation process using extraction chromatography with HDEHP is investigated. To select the optimal separation conditions for Np from the other actinides and from each other, their extraction by HDEHP has been studied in such solutions as HCl, NHO₃, HClO₄, HF, H₂C₂O₄ and H₃PO₄. A two-step separation procedure yields fractions of individual actinide elements.     

Separation of no-carrier-added 113,117mSn and 113m,114mIn from alpha particle irradiated natural cadmium target

A natural cadmium foil was irradiated by 42 MeV α-particles to produce ^113,117mSn, ^{111,113m,114m}In simultaneously in the target matrix. After the complete decay of short lived radionuclides, long-lived NCA products were separated sequentially from the bulk cadmium by liquid–liquid extraction using di-(2-ethylhexyl)phosphoric acid (HDEHP) dissolved in cyclohexane as organic phase and HCl as aqueous phase. At the optimum condition, 10^?2 M HCl and 5 % HDEHP, NCA In along with NCA Sn radionuclides (75 %) were separated from the bulk Cd resulting to high separation factors of 2.7 × 10⁴ (D _In/D _Cd) and 500 (D _Sn/D _Cd), respectively. The NCA In was stripped back completely to the aqueous phase by 6 M HCl leaving NCA Sn in the HDEHP phase with a separation factor (D _Sn/D _In) of 3.94 × 10⁶.     

Extraction of99Mo-molybdophosphate and99mTc-pertechnetate from various acid solutions by bis/2-ethylhexyl/ phosphoric acid

The extractability of⁹⁹Mo-molybdophosphoric acid H₃/PMo₁₂O₄₀/ and^99mTc-pertechnetic acid /PTcO₄/ in 20% (v/v) bis /2-ethylhexyl/ phosphoric acid /HDEHP/ in benzene has been investigated at different concentrations of HCl, HBr and HNO₃ acids. The effect of extractant concentration and diluent on the extractability of molybdophosphoric and pertechnetic acids with 20% (v/v) HDEHP in benzene from different concentrations of HCl acid has also been studied.⁹⁹Mo-molybdo-phosphoric acid was found to be selectively extracted and separated from^99mTc-pertechnetic acid with 20% HDEHP in benzene at an acidity of about 0.49M HCl, HBr and HNO₃. The extractability of H₃/PMo₁₂O₄₀/ from these acids generally follows the decreasing order HBr>HCl>HNO₃. The separation factors /K_d molybdophosphoric/K_d pertechnetic/ were found to be 12.9×10⁵ and 7.6×10⁵ for HBr and HCl, respectively. The extractability of pertechnetic acid follows the order HCl>HBrHNO₃. Benzene is the diluent due to its radiation stability. A new procedure for the separation of^99mTc from⁹⁹Mo was suggested.     

Tracer scale solvent extraction separation of tantalum from niobium using di-(2-ethylhexyl)-phosphoric acid as extractant

A simple solvent extraction procedure for the efficient separation of the radioactive tracers⁹⁵Nb and¹⁸²Ta from each other in a mixture using di-(2-ethylhexyl)phosphoric acid (HDEHP) as extractant is described. Tantalum was found to be quantitatively extracted from an aqueous madium, which is 1.6N in HCl and 10^?2 M in oxalic acid, with a HDEHP solution of 0.1 M concentration. Extractabilities of both niobium and tantalum in mineral acids like HCl, H₂SO₄ and HNO₃ and in some organic acids like oxalic, citric, etc., in HDEHP under the experimental conditions were also studied. The reliability of the separation procedure was verified further by γ-ray spectrometry.     

Separation of heavy ion induced carrier free europium isotopes from bulk quantity of cesium

Theoretical calculation shows considerable cross section for production of^145,146Eu through¹³³Cs(¹⁶O,xn) nuclear reaction. To reduce the trials with costly particle accelerators beam time experimental simulation for separation of carrier free europium from cesium target matrix has been performed. Trace amounts of^152,154Eu have been separated from macro and trace amounts of cesium. A high separation factor has been achieved when 1% HDEHP and 10⁻³M HCl is used as organic and aqueous phase respectively. Trace europium has been successfully back extracted into HCl, ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) medium.     

Separation of <Superscript>139</Superscript>Ce using solvent extraction technique from La<Subscript>2</Subscript>O<Subscript>3</Subscript> target irradiated by 14.7 MeV protons

The radiochemical separation of no-carrier-added cerium from proton irradiated lanthanum was studied by solvent extraction using DEE, TBP and TPPO, the latter reagent being employed for the first time for separation of radiocerium from bulk of lanthanum. Distribution coefficients of cerium and lanthanum were investigated as a function of equilibrium time and concentration of HNO₃. A mixture of 0.05M K₂Cr₂O₇ and 0.1M H₂SO₄ was used as an oxidizing agent to improve the separation efficiency of cerium. A comparative study of the three extractants released that DEE is the best for separation of cerium from bulk of lanthanum oxide. The target was prepared by pressing. The production of ¹³⁹Ce of high radionuclidic purity and chemical purity via irradiation of lanthanum oxide target at MGC-20 cyclotron with protons of energy 14.5 MeV is described. The experimental yield was found to be 153 kBq/μA·h.     

Separation of carrier-free 111In, 116,117Te and 116,116m,117Sb from a 11B-induced silver target

Heavy-ion activation with ~55 MeV ¹¹B beam on silver target leads to the production of carrier-free ¹¹¹In, ^116,117Te and ^116,116m,117Sb radioisotopes in the target matrix. Liquid-liquid extraction, using Aliquat-336 and trioctylamine (TOA) as liquid anion exchangers in HNO₃ and HCl medium, respectively, and di-(2-ethylhexyl)phosphoric acid (HDEHP) as liquid cation exchanger in ammoniacal medium was used to investigate the separation of the produced radioisotopes from the bulk target matrix.     

Separation of europium and thulium from mixed KI−H2SO4 solutions

The extraction of Tm with HDEHP from H₂SO₄, HCl and HBr is inversely proportional to the third power of the hydrogen ion concentration while the extraction is small with HDEHP, LA-2 and TBP from binary mixtures of acids. The extraction of both Eu and Tm with HDEHP from KI solutions decreases in the presence of small concentrations of H₂SO₄. The decrease is sharper in case of Eu leading to high separation factors between Eu and Tm from KI?H₂SO₄ mixtures.     

Separation of some burn-up monitors from the UO2−Al nuclear fuel

The separation of caesium, cerium, neodymium, europium and uranium from the UO₂?Al fuel samples has been studied. Experiments were carried out with unirradiated and irradiated fuel samples. The dissolved samples contained a large excess of aluminium with respect to uranium (the molar ratio Al∶U was ～17∶1). The presence of aluminium particularly disturbed the chromatographic separation of the lanthanide burn-up monitors. The latter were separated from uranium and aluminium and from one another using the precipitation method with a cerium carrier, followed by extraction with HDEHP and a column separation with the same extractant. Aluminium and uranium first were determined together as precipitates with 8-hydroxychinoline, and then the uranium contribution was independently assayed potentiometrically with a K₂Cr₂O₇ solution.     

Cerium isotope partition in HNO3/TBP or HDEHP extraction systems

The^142/140Ce unit separation factors (q) for cerium(III)-cerium(IV) exchange reaction in an extraction system containing Ce(IV) in tri-n-butyl phosphate (TBP) or di(2-ethylhexyl) phosphoric acid (HDEHP) and Ce(III) in nitric acid were determined. The value of q was found to be 1.00054±0.00012 (2) in 6M HNO₃/TBP and 1.00078±0.00028 in 6M HNO₃/HDEHP extraction systems. The dehydration and complex formation processes and their contribution to reduced partition function ratios (RPFR's) are discussed.     

Carrier-free separation of167Tm from Yb,Er and Ho targets by reversed-phase extraction chromatography and preparation for its medical use

Reversed-phase extraction chromatography employing a Daiflon-supported HDEHP column and HCl as eluent was examined for carrier-free separation of¹⁶⁷Tm from a photo-irradiated Yb target and also from particle-bombarded Er and Ho targets. The examination was performed with radioassays of radioactive Tm and Yb tracers and⁵⁷Co--induced X-ray analysis of Er and Ho. An example of the separation of about 1 mCi of¹⁶⁷Tm from a 100 mg irradiated Yb target enriched in¹⁶⁸Yb and a procedure for the final preparation for medical use are described. The YbSO₄ precipitation could be combined with this chromatographic separation of¹⁶⁷Tm from a more massive Yb target of natural abundance, weighing several tens of grams. A procedure for YbSO₄ precipitation is also presented in the Appendix.     

Trennung von spaltprodukten durch Extraktionschromatographie

The separation of fission products which form anionic species in mineral acids and of uranium and neptunium from samples of neutron-irradiated uranium is described. The method used is extraction chromatography with tri-n-butylphosphate (TBP) and di-(2-ethylhexyl)-orthophosphoric acid (HDEHP) as extractants and polytrifluoromonochloroethylene powder as the solid support. In the first column Zr, U and Np are extracted with TBP from 8N HNO₃/NaClO₃. In the second column, HDEHP is applied as extractant and 9N HCl/NaClO₃ as the mobile phase for the isolation of Nb, Sb, and I, and in the third column (HDEHP), the rare earths and Mo are extracted from 0.1N HCl. Finally with the fourth column (TBP), Te and Tc are isolated from 6N HCl. These four groups of elements are further separated by elution from the columns. From the final effluent containing Ru, Rh, Cs, Sr, and Ba, Ru is distilled from HClO₄, and Rh is precipitated with NH₄OH. The determination of chemical yields with X-ray fluorescence techniques is described for Zr, Mo, Te, Cs, Ce and U.

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Aus einer Dissertation, Mainz 1967.     

Sequential separation of transuranic elements and fission products from uranium metal ingots in electrolytic reduction process of spent PWR fuels

A sequential separation procedure has been developed for the determination of transuranic elements and fission products in uranium metal ingot samples from an electrolytic reduction process for a metallization of uranium dioxide to uranium metal in a medium of LiCl-Li₂O molten salt at 650 °C. Pu, Np and U were separated using anion-exchange and tri-n-butylphosphate (TBP) extraction chromatography. Cs, Sr, Ba, Ce, Pr, Nd, Sm, Eu, Gd, Zr and Mo were separated in several groups from Am and Cm using TBP and di(2-ethylhexyl)phosphoric acid (HDEHP) extraction chromatography. Effect of Fe, Ni, Cr and Mg, which were corrosion products formed through the process, on the separation of the analytes was investigated in detail. The validity of the separation procedure was evaluated by measuring the recovery of the stable metals and ²³⁹Pu, ²³⁷Np, ²⁴¹Am and ²⁴⁴Cm added to a synthetic uranium metal ingot dissolved solution.     

Reversed phase chromatographic separation of zirconium,niobium and hafnium tracers with HDEHP

Effective separation of the congeneric pair of elements, zirconium and hafnium and also niobium which was in admixtures with zirconium as daughter in its isotopic form were achieved through reversed phase column and paper extraction chromatographic procedures using di-(2-ethylhexyl)phosphoric acid (HDEHP) as the liquid exchanger. In reversed phase column chromatographic separation, the tracers,⁹⁵Zr,⁹⁵Nb and^175,181Hf, were extracted by HDEHP impregnated on kieselguhr and were sequentially eluted with 6N H₂SO₄+xN oxalic acid+H₂O₂(where x=0.1, 0.5 and 2). Similarly, in reversed phase paper chromatographic study in which a coating of HDEHP on Whatman No. 1 chromatographic paper was used as stationary phase, the mobile phase, 18N H₂SO₄+0.1N oxalic acid + H₂O₂, helped in separating the elements with favorable separation factors. Under the optimal conditions, the separation and decontamination of the elements in both methods were found to be quantitative, as verified by -spectrometric studies.     

Separation of neptunium, plutonium, americium and curium from uranium with di-(2-ethylhexyl)-phosphoric acid (HDEHP) for radiometric and ICP-MS analysis

The possibility of using di-(2-ethylhexyl)-phosphoric acid (HDEHP) in solvent extraction for the separation of neptunium, plutonium, americium and curium from large amounts of uranium was studied. Neptunium, plutonium, americium and curium (as well as uranium) were extracted from HNO₃, whereafter americium and curium were back-extracted with 5M HNO₃. Thereafter was neptunium back-extracted in 1M HNO₃ containing hydroxylamine hydronitrate. Finally, plutonium was back-extracted in 3M HCl containing Ti(III). The method separates²³⁸Pu from²⁴¹Am for α-spectroscopy. For ICP-MS analysis, the interferences from²³⁸U are eliminated: tailing from²³⁸U, for analysis of²³⁷Np, and the interference of²³⁸UH⁺ for analysis of²³⁹Pu. The method has been used for the analysis of actinides in samples from a spent nuclear fuel leaching and radionuclide transport experiment.     

Chemical process study on the separation of gadolinium-153

Three routes of chemical processes for a multicurie production of¹⁵³Gd have been established and demonstrated using one gram of Eu₂O₃ as target irradiated under a neutron flux of 5.0·10¹³n/cm²/s for 42 days. Simulated experiments with the synthetic solution containing appropriate amounts of Gd and Eu and the tracers were performed throughout the established chemical process for verifying its feasibility and the effectiveness. The results show that a high specific activity of 100 Ci/g Gd with the desired radionuclide purity of greater than 99.999% of¹⁵³Gd can be obtained. The chemical yield and processing time among the processes were compared.     

Determination of stability constants of U(VI), Np(VI) and Pu(VI) with chloride ions by extraction chromatography

The complex formation of U(VI), Np(VI) and Pu(VI) with chloride ions was studied in HClO₄−HCl solutions at ionic strength of 2.0 and [H⁺]=2.0M by the method of extraction chromatography using dilute HDEHP as the stationary phase.     

Recovery of uranium from U3O8 irradiated with thermal neutrons

The extraction of uranium with different concentrations of HDEHP in n-hexane from varying concentrations of nitric acid solutions was investigated. Uranium in the organic phase was quantitatively stripped with a solution containing 8M H₂SO₄ and 6M HCl, the partition coefficient was determined by X-ray fluorescence and U. V. spectrophotometry. The assay of⁹⁵Zr,⁹⁵Nb,²³⁹Np and other gamma-emitters was made with a Ge(Li) detector coupled to a 4096 multichannel analyzer.