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1.
The radioisotope 99Mo generated through the fission of neutron-irradiated uranium targets was separated in an extremely radiochemically pure
state. The target dissolution mixture was run on a silica gel column whereby the 95Zr− 95Nb activity, the serious radiocontaminants of 99Mo, was adsorbed on the gel. The effluent from the gel column was processed and treated with sodium dihydrogen phosphate.
The processed solution was run on an activated alumina column whereby 99Mo was adsorbed as phospho-molybdate complex ion, then desorbed from the column as the molybdate ion by eluting with 10% NaOH
solution. By recycling the adsorption and desorption steps on alumnia, 99Mo was finally obtained totally free from all other radiocontaminants. 相似文献
2.
Adsorption and desorption of 95Zr− 95Nb, 99Mo, 103Ru, 132Te and 239Np in a HCl-alumina system were studied in order to purify 99Mo and 132Te obtained by the cation-exchange separation of fission products and to prepare highly pure 99mTc and 132I generators. 99Mo and 132Te, of which radionuclidic purity was over 99.99% and 99.999%, respectively, could be obtained by passing the cation-exchange
separated Mo and Te fractions through alumina columns, by washing with HCl and finally by eluting 99Mo with 1M NH 4OH and 132Te with 3M NaOH. In order to raise the recovery of 99Mo and 132Te from the alumina columns, they should be eluted as quickly as possible after the adsorption. The direct use of the alumina
column containing 99Mo or 132Te as the generator allowed milking of 99mTc or 132I, of which radionuclidic purity was over 99.999%. Milking yields of 99mTc with 0.1M HCl and 132I with 0.01M NH 4OH were 77% and 90%, respectively. The latter value was much higher than that in usual performance of the generator. 相似文献
3.
The radioisotope 99Mo was separated from a mixture of 235U fission products in the presence of Hg 2+ by sorption on a chromatographic column filled with Al 2O 3 and elution with 1M NH 4OH. Trace impurities of 131I in the molybdenum fraction were eliminated by selective sorption on silver iodide or by repeated sorption of 99Mo on Al 2O 3. 相似文献
4.
The potential uses of hydrous oxides in the treatment of radioactive wastes may be affected by the physical-chemical properties
of these materials. The sorption behavior of trace level (less than 10 -14 g/ml) 235U fission products in aqueous solutions was studied under static conditions on TiO 2, MnO 2 and SnO sorbents. A variety of anions, cations and neutral species of 132Te, 95Zr, 99Mo and 103Ru in aqueous solutions at 1, 3, 5, 7 and 10 pH values were identified and their retention values were calculated. High voltage
electrophoresis was used to establish the chemical species of these radioisotopes formed in the solution.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
The formation property of Mo precipitate was investigated and improved the existing process was using H 2O 2 that acts as an interfering compound in a subsequent alumina adsorption process. The property of the Mo precipitate was investigated by using SEM, FTIR, TG-DTA, and XRD. The simulated solution consisted of 1M nitric acid containing seven elements (Mo, I, Ru, Zr, Ce, Nd, Sr) and their radioactive tracers. As a result, the precipitate was composed of the Mo precipitate and re-precipitated a-benzoinoxime which was added excessively for increasing the precipitation efficiency. It was confirmed that the Mo precipitate was formed by the reaction of two a-benzoinoxime molecules and one MoO 2
2+. Molybdenum precipitate was dissolved in 0.4M NaOH solution within 5 minutes without H 2O 2. Hydrogen peroxide induced only the rapid dissolution of the a-benzoinoxime re-precipitate. Also, the dissolution method without H 2O 2 was favorable in the purification aspect because Zr and Ru were contained as a small fraction of 1.3% and 7.7%, respectively, in the dissolving solution. 相似文献
6.
The selective extraction of yttrium from heavy lanthanide by liquid-liquid extraction using CA-100 in the presence of the complexing agent, such as EDTA, DTPA, and HEDTA was investigated. The extraction of heavy lanthanide in the present of the complexing agent was suppressed when compared to that of Y because of the masking effect, but the selective extraction of Y was enhanced. All complexing agents formed 1:1 complex with rare earth elements (RE), and only free rare earth ions could take part in the extraction. The condition for separation was obtained by exploring the effects of the complexing agent concentration, the extractant concentration, pH and the equilibration time on the extraction of the heavy rare earth elements. 相似文献
8.
Extraction-chromatographic separation of uranium from fission products was performed using undiluted tributyl phosphate sorbed on Chromosorb W as a stationary phase, and nitric acid (1: 3) as a mobile phase. Most of the fission products that contributed greatly to the radiation level of the sample passed through the column; this effected considerable decontamination. Uranium retained on the column was quantitatively recovered by elution with water. 相似文献
9.
In Argentina, at the Ezeiza Atomic Center, 131I is produced by wet distillation of natural tellurium dioxide irradiated with thermal neutrons in a pool-type reactor. In
order to recover the 131I present in the production process of fission 99Mo obtained by irradiation of UAL x/Al targets (with 90% enriched uranium) a separation method was developed. Iodine isotopes can be separated from a sodium
hydroxide solution containing fission products using a column filled with alternate beds of glass microspheres and porous
metal silver. Tests with tracers were performed in radiochemical laboratory. Following this results, a series of tests with
higher activities (3 TBq of 99Mo and 0.7 TBq of 131I) were carried out in hot cells. Molybdenum passes through the silver column, while 131I retention was 92–97% in tracer test and 90% in optimised hot cell tests. This result depends on several facts that are discussed.
An initial separation of iodine isotopes diminishes radiation damage on ion-exchange resin used in the subsequent molybdenum
purification, improving its retention and elution yield. 相似文献
10.
Technetium is separated from the bulk of fission products and other elements in dissolved nuclear fuel by a ferric hydroxide precipitation followed by filtration and loading of the filtrate on an anion exchange resin. The technetium remains on the resin presumably as pertechnate ion. The resin is exposed to a neutron flux in a nuclear reactor activating 99Tc to 100Tc which decays with the emission of a 539keV gamma-ray with a 15.8 second half-life. This gamma-ray is conveniently counted with conventional solid state techniques.Work performed under contract to the U. S. Department of Energy under contract number DE-ACO7-76IDO1570. 相似文献
11.
A new technique for the separation of 99mTc from low specific activity 99Mo is reported. A separation based on the principle of precipitation of 99Mo as calcium molybdate has been investigated. On precipitating 99MoO
4
2–
from alkaline solution as calcium molybdate under controlled conditions, the 99mTcO
4
–
is found to remain quantitatively in the supernatant solution with little carry-over of 99Mo. This calcium molybdate ( 99Mo) could be redissolved and reprecipitated at regular intervals, yielding 99mTc quantitatively in aqueous neutral solutions. Calcium molybdate precipitates containing up to 1.5 GBq of 99Mo and 130–180 mg of molybdenum were prepared and evaluated. The performance in terms of repeated 99mTc separation gave yields of 75–93% with acceptable readionuclidic and radiochemical purity. 相似文献
12.
The extraction of Ce (IV) by di-(2-ethylhexyl)-phosphoric acid (HDEHP) has been studied as a function of nitric acid concentration. Using the distribution coefficient data, the optimum conditions for recovery of Ce (IV) from nitric acid medium were arrived at. Under the conditions employed for Ce(IV), a small percentage of Ru was also found to be extracted. Cerium could be selectively stripped from the organic phase with 8M HNO 3/30% H 2O 2 solution. This procedure led to the recovery of 144Ce free of 106Ru. Based on the solvent extraction data, an extraction-chromatographic procedure employing HDEHP (40% w/w) loaded on Amberlite XAD-7 as the stationary phase was developed for the isolation of pure, carrier-free 144Ce from the spent fuel solution. 相似文献
13.
A new way of radiochemical separation of carrier-free 115mIn from 115Cd and 132I from 132Te over the column of zirconium oxide is described. Activities of Cd and In in equilibrium in dilute acetic acid solution
were bufferred with dilute sodium acetate and fed into the column at a pH 7, when cadmium activity passed out unadsorbed and
the 115mIn was adsorbed in the column. A study of the γ-ray peak of the separated 115mIn showed that the product is of high radionuclidic purity. Te-I pair was separated by passing the weakly acidic solution
of 132Te and 132I in the presence of AgNO 3 and Na 2SO 3, through the column where both activities were adsorbed. Iodine was washed outh with 5% sodium thiosulphate solution and
the retained tellurium activity was later washed out with 6M HNO 3. The β-decay study showed that the separated 132I product is of high radiochemical purity. The processes took less than half an hour and the yields were quantitative. 相似文献
14.
TODGA–PAN composite sorbent and (PhSO3H)2–BTPhen in nitric acid solution were employed as a system for separation of curium from americium. The influence of aqueous phase composition (complexing agent and nitric acid concentrations) on weight distribution coefficients and Cm/Am separation factor was studied in batch experiments with trace amounts of 241Am and 244Cm. Based on the results obtained, column experiment was designed and conducted. The Cm/Am separation factor of 3.8 ± 0.1 found in batch experiments with TODGA–PAN could be reproduced also in column experiment resulting in good separation of Cm from Am. The efficiency of Cm separation from Am in the TODGA–PAN system was compared with the analogous system with DGA resin (Triskem International). After separation on a 0.5 mL column (φ4.7 × 29 mm) the Cm fraction containing 93% of Cm(III) contained only 3% of Am(III) in optimum conditions. 相似文献
16.
The use of glycine as complexing agent for chromatographie separation of palladium from platinum, or palladium from iridium, on cellulose anion-exchangers has been investigated and found possible over a wide range of concentration ratios. The method can be used for analysis of Pd-Ir alloys. The nature of the complexes taking part in the ion-exchange has been identified. 相似文献
17.
Tetracycline in solution of benzyl alcohol was used as an extracting agent to separate uranium from interfering elements in the determination of uranium and of isotopic ratio 235U/ 238U by neutron activation analysis. Separation gives a recovery of 97% for uranium and the interferences from matrices of pitchblende and monazite are eliminated.From a dissertation submitted by R. Petrauskas to the University of São Paulo in partial fulfilment for a Master of Science Degree in Nuclear Technology. 相似文献
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