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1.
I. P. Alimarin A. Z. Miklishanskii Yu. V. Yakovlev 《Journal of Radioanalytical and Nuclear Chemistry》1970,4(1):45-51
A method with a sensitivity of 2·10−7 to 1·10−10% has been developed for determining Yb, Ho, Dy, Gd, Eu, Sm and La impurities in metallic uranium by means of neutron activation.
The method is based on a preliminary chromatographic separation of the total amount of rare earth elements from uranium by
passing the solution in sulphuric acid through KU-2 cation exchange resin and eluting the traces of uranium retained by the
resin with a solution of ascorbic acid. The rare earth impurities are then eluted from the resin with 4–5N HCl, evaporated, and irradiated for 20 hours with a neutron flux of 1.2·1013 n·cm−2·sec−1. Subsequently the traces of the rare earth elements are co-precipitated with Fe(OH)3, dissolved in concentrated HCl and separated from the iron and other impurities by passing the solution through Dowex 1X8
anion exchange resin in the chloride form. The individual rare earth elements are then separated from each other using KU-2
cation exchange resin and a solution of ammonium α-hydroxyisobutyrate as the eluant. 相似文献
2.
R. K. Singhal P. K. Sharma M. K. T. Bassan H. Basu A. V. R. Reddy 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(1):149-156
During this work selective separation of uranium from rock phosphate and columbite mineral was done before its quantitative
estimation by using Inductively Coupled Plasma Optical Emission Spectrometery (ICP-OES). Uranium from the rock phosphate and
columubite was extracted by sodium peroxide fusion followed by leaching in 2 M HNO3. To avoid spectral interference in the estimation of uranium by ICP-OES, the selective separation of uranium from the leachate
was carried out by using two different extractants, 30% Tributyl Phophates (TBP) in CCl4 and a equi-volume mixture of Di(2-ethylhexyl) phosphoric acid (D2EHPA) & TBP in petrofin. Uranium was stripped from the organic
phase by using 1 M ammonium carbonate solution. Determination of uranium by ICP-OES was done after dissolving the residue
left after evaporation of ammonium carbonate solution in 4% HNO3. The concentration of the uranium observed in the rock phosphates samples was 40–200 μg g−1 whereas in columbite samples the concentration range was 100–600 μg g−1. Uranium concentration evaluated by ICP-OES was complimented by gamma & alpha spectrometry. Concentration of uranium evaluated
by gamma spectrometry in case of rock phosphate and coulmbite was in close agreement with the uranium content obtained by
ICP-OES. Uranium determination by alpha spectrometry showed only minor deviation (1–2%) from the results obtained by ICP-OES
in case of rock phosphates whereas in case of coulmbites results are off by 20–30%. 相似文献
3.
Smeer Durani M. Krishnakumar K. Satyanarayana 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(2):215-220
A simple, effective and low cost solid phase extraction procedure was standardized for the trace and ultra-trace level determination of rare earth impurities, such as, Ce, Dy, Sm, Gd, Eu, Er etc. which act as neutron poisons, in nuclear grade uranium oxide (U3O8?>?99.9% by weight). The method involves selective separation of these elements as their fluorides with the help of activated charcoal from major uranium matrix followed by determination by ICP-MS and high resolution ICP-OES. The residual uranium content of the solution was <10???g/mL. The recovery of REEs ranges from 85 to 105%. The method was validated with nuclear grade uranium oxide standards CRM-I to CRM-V (BARC, Mumbai, India) in addition to some synthetic standards. The RSD of the method was ±12% (n?=?3). 相似文献
4.
R. K. Singhal H. Basu M. K. T. Bassan M. V. Pimple V. Manisha D. K. Avhad P. K. Sharma A. V. R. Reddy 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(2):675-681
Direct determination of uranium in the concentration range of 8 μg L−1 to mg L−1 in water samples originating from different geochemical environments has been done using Inductively Coupled Plasma-Optical
Emission Spectroscopy (ICP-OES). Uranium detection with 2–3% RSD (relative standard deviation) has been achieved in water
samples by optimizing the plasma power, argon and sheath gas flow. These parameters were optimized for three different emission
lines of uranium at 385.958, 409.014 and 424.167 nm. Interference arising due to the variation in concentration of bicarbonate,
sodium chloride, calcium chloride, Fe and dissolved organic carbon (DOC) on the determination of uranium in water samples
was also cheeked as these are the elements which vary as per the prevailing geochemical environment in groundwater samples.
The concentration of NaHCO3, CaCl2 and NaCl in water was varied in the range 0.5–2.0%; whereas Fe ranged between 1 and 10 μg mL−1 and DOC between 0.1–1%. No marked interference in quantitative determination of uranium was observed due to elevated level
of NaHCO3, CaCl2 and NaCl and Fe and DOC in groundwater samples. Concentration of uranium was also determined by other techniques like adsorptive
striping voltametry (AdSv); laser fluorimetry and alpha spectrometry. Results indicate distinct advantage for uranium determination
by ICP-OES compare to other techniques. 相似文献
5.
A smart fully automated system is proposed for determination of thorium and uranium in a wide concentration range, reaching
environmental levels. The hyphenation of lab-on-valve (LOV) and multisyringe flow injection analysis (MSFIA), coupled to a
long path length liquid waveguide capillary cell, allows the spectrophotometric determination of thorium and uranium in different
types of environmental sample matrices achieving high selectivity and sensitivity levels. Online separation and preconcentration
of thorium and uranium is carried out by means of Uranium and TEtraValents Actinides resin. The potential of the LOV–MSFIA
makes possible the full automation of the system by the in-line regeneration of the column and its combination with a smart
methodology is a step forward in automation. After elution, thorium(IV) and uranium(VI) are spectrophotometrically detected
after reaction with arsenazo-III. We propose a rapid, inexpensive, and fully automated method to determine thorium(IV) and
uranium(VI) in a wide concentration range (0–1,200 and 0–2,000 μg L-1 Th and U, respectively). Limits of detection reached are 5.9 ηg L-1 of uranium and 60 ηg L-1 of thorium. Different water sample matrices (seawater, well water, freshwater, tap water, and mineral water), and a channel
sediment reference material which contained thorium and uranium were satisfactorily analyzed with the proposed method. 相似文献
6.
Summary Rare earth impurities in high-purity Gd2O3 have been determined by ICP-OES. HREE except Ho were analysed by directly nebulising 1 mg/ml of the matrix solution and the LREE were analysed after separation on an anionexchange Dowex 1×8 resin. The recovery studies show nearly 100% separation. The determination of 30 ppm of HREE in gadolinium oxide is possible. 相似文献
7.
Determination of impurities in uranium matrices by time-of-flight ICP-MS using matrix-matched method
S. Bürger L. R. Riciputi D. A. Bostick 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(3):491-505
The analysis of impurities in uranium matrices is performed in a variety of fields, e.g., for quality control in the production
stream converting uranium ores to fuels, as element signatures in nuclear forensics and safeguards, and for non-proliferation
control. We have investigated the capabilities of time-of-flight ICP-MS for the analysis of impurities in uranium matrices
using a matrix-matched method. The method was applied to the New Brunswick Laboratory CRM 124(1–7) series. For the seven certified
reference materials, an overall precision and accuracy of approximately 5% and 14%, respectively, were obtained for 18 analyzed
elements. 相似文献
8.
A selective and effective column chromatographic separation method has been developed for uranium(VI) using poly[dibenzo-18-crown-6].
The separation was carried out in L-valine medium. The adsorption of uranium(VI) was quantitative from 1.0 × 10−4 to 1 × 10−1 M of L-valine. Amongst various eluents 2.0–8.0 M hydrochloric acid, 1.0–4.0 M sulfuric acid, 1.0–5.0 M perchloric acid, 6.0–8.0
M hydrobromic acid and 5.0–6.0 M acetic acid were found to be efficient eluents for uranium(Vl). The capacity of poly[dibenzo-18-crown-6]
for uranium(VI) was 0.25 ± 0.01 mmol/g of crown polymer. Uranium(VI) was separated from number of cations and anions in binary
mixtures in which most of the cations and anions show a very high tolerance limit. The selective separation of uranium(VI)
was carried out from multicomponent mixtures. The method was extended to determination of uranium(VI) in geological samples.
The method is simple, rapid and selective with good reproducibility (approximately ∼2%). 相似文献
9.
I. I. Sadikov A. V. Rakhimov M. I. Salimov V. G. Zinov’ev N. M. Mukhamedshina F. A. Tashimova 《Journal of Radioanalytical and Nuclear Chemistry》2009,280(3):489-493
We have developed a radiochemical neutron activation analysis technique (RNAA) of pure uranium with using extraction chromatographic
separation of 239Np from impurity elements in TBP-6M HNO3 media. The estimation of influence of fission products of 235U on the results by radiochemical neutron activation analysis has been carried out. For it we have performed NAA with preconcentration
of impurity elements. Experiments show that in this case the apparent concentration of Y, Zr, Mo, Cs, La, Ce, Pr, Nd exceeds
the true concentration by 2500–3000 times. Therefore, determination of these elements is not possible by RNAA. This technique
allowed to use the determination of 26 impurity elements with detection limit 10−5–10−9% by mass. This developed technique may be used for the determination of impurities in uranium and its compounds. 相似文献
10.
A simple and rapid inductively coupled plasma optical emission spectrometric method for the determination of trace level impurities like REEs, Y, Cd, Co, V, Mg, B, Ca, Cr, Mn, Ni, Cu, Zn and Al in uranium oxide samples is described. The method involves solvent extraction separation of uranium from 6 M HNO3 acid medium using di (2-ethyl hexyl) phosphoric acid in toluene, which selectively separates uranium leaving behind the trace impurities in the aqueous media, for quantification by ICP-OES. The method has been applied to few synthetic samples and five certified reference U3O8 standards. The results are compared with other methods such as TBP-TOPO-CCl4 and 1,2 diaminocyclohexane N,N,N′,N′-tetra acetic acid (CyDTA)–ammonium hydroxide (NH4OH) separation techniques. Different experimental parameters like contact time, acidity, aqueous to organic ratio etc., are optimized for better and accurate results. The method is simple, rapid, accurate and precise for all the studied elements, showing a relative standard deviation of 1.5–12.0% at trace levels studied (5.5–12% at 0.2 μg/mL and 1.5–6.0% at 0.5 μg/mL), on the synthetic samples prepared from high purity oxides. 相似文献
11.
A. N. Dubey G. R. Relan S. Vaidyanathan 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(3):741-746
A derivative spectrophotometric method has been developed for the simultaneous determination of uranium and plutonium at trace
levels in various process streams in 3M HNO3 medium using Arsenazo III. The method was developed with the objective of measuring both uranium and plutonium in the same
aliquot in fairly high burn-up fuels. The first derivative absorbances of the uranium and plutonium Arsenazo III complexes
at 632 nm and 606.5 nm, respectively, were used for their quantification. Mixed aliquots of uranium (20–28 μg/ml) and plutonium
(0.5–1.5 μg/ml) with U/Pu ratio varying from 25 to 40 were analysed using this technique. A relative error of about 5% was
obtained for uranium and plutonium. The method is simple, fast and does not require separation of uranium and plutonium. The
effect of presence of many fission products, corrosion products and complexing anions on determination of uranium and plutonium
was also studied. 相似文献
12.
Jyothi Rajesh Kumar Joon-Soo Kim Jin-Young Lee Ho-Sung Yoon 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(2):301-308
The present scientific study on uranium(VI) solvent extraction and vanadium(V) separation from sulfate solutions using Alamine
336 as an extractant diluted in kerosene was established. The preliminary experiments indicating the uranium extraction process
will follow the solvation as well as ion-exchange mechanisms. In the present acid region (0.1–1.0 mol dm−3 H2SO4) it showing the ion-exchange type mechanism. Time (1–120 min) and temperature (25–55 °C) not influencing the present extraction
system. Other experimental parameters like loading capacity of Alamine 336, stripping of uranium from loaded organic phase,
recycling of Alamine 336 and separation of uranium(VI)/vanadium(V) was studied. 相似文献
13.
Ankita Rao Pradeep Kumar K. L. Ramakumar 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(2):247-257
Uranium from different uranium oxide matrices was extracted with tri-n-butyl phosphate–nitric acid (TBP–HNO3) adduct using supercritical carbon dioxide (SC CO2). While 30 min dissolution time at 323 K was sufficient for U3O8 and UO2 powder, UO2 granule (at 333 K) and crushed green pellet (at 353 K) required 40 min. Crushed sintered pellet required 60 min at 353 K
for complete dissolution. Influence of various experimental parameters such as temperature, pressure, volume of TBP–HNO3 adduct, acidity of nitric acid used for preparing TBP–HNO3 adduct and extraction time on uranium extraction efficiency was also investigated. For UO2 powder, temperature of 323 K, pressure of 15.2 MPa, 1 mL TBP–HNO3 adduct, 10 M nitric acid and 30 min extraction time was found to be optimum. ~70% uranium extraction efficiency was obtained
on extraction with SC CO2 alone which increased to 90% with the addition of 2.5% TBP in SC CO2 stream. Extraction efficiency was found to vary linearly with TBP percentage and nearly complete uranium extraction (~99%)
was observed with 20% TBP. Nearly complete extraction was also achieved with addition of 2.5% thenoyltrifluoroacetylacetone
(TTA) in methanol. The optimized procedure was extended to remove uranium from simulated tissue paper waste matrix smeared
with uranium oxide solids. 相似文献
14.
Summary A method has been developed for separation and quantitation of midecamycin A1 and related impurities by high-performance liquid chromatography with evaporative light-scattering detection (ELSD). Chromatographic
conditions included use of a Diamonsil C18 column; the mobile phase was 52:48 acetonitrile −0.2 mol L−1 ammonium formate solution (adjusted to pH 7.3 with triethylamine) at a flow rate of 1 mL min−1. The column temperature was 35°C, the shift tube temperature of the ELSD was 105°C, and the gas flow rate of the ELSD was
3.0 L min−1. The response factors of midecamycins in HPLC-ELSD were the same; the linear equation wasy=599292.44x+2868618.04,r=0.9979, the linear range was 5–80 μg,RSD=0.21–1.54%, and theLOD andLOQ were 0.36 and 1.2 μg, respectively. The method was simple, quick, and precise and could be used to determine midecamycin
and its related impurities directly. 相似文献
15.
V. C. Adya A. Sengupta B. A. Dhawale B. Rajeswari S. K. Thulasidas S. V. Godbole 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(3):843-848
Trace metallic impurity analysis by spectroscopic techniques is one of the important steps of chemical quality control of
nuclear fuel materials. Depending on the burn-up and the storage time of the fuel, there is an accumulation of 241Am in plutonium based fuel materials due to β decay of 241Pu. In this paper, attempts were made to develop a method for separation of 241Am from 1.2 kg of analytical solid waste containing 70% U, 23% Pu, 5% Ag and 1–2% C as major constituents along with other
minor constituents generated during trace metal assay of plutonium based fuel samples by d. c. arc carrier distillation atomic
emission spectrometry. A combination of ion exchange, solvent extraction and precipitation methods were carried out to separate
~45 mg of 241Am as Am(NO3)3 from 15 L of the analytical waste solution. Dowex 1×4 ion exchange chromatographic method was used for separation of Pu whereas
30% TBP–kerosene was utilized for separation of U. Am was separated from other impurities by fluoride precipitation followed
by conversion to nitrate. The recovery of Pu from ion exchange chromatographic separation step was ~93% while the cumulative
recovery of Am after separation process was found to be ~90%. 相似文献
16.
S. Ganesh Fahmida Khan M. K. Ahmed P. Velavendan N. K. Pandey U. Kamachi Mudali S. K. Pandey 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(1):331-334
A simple and rapid, laser fluorimetric method for the determination of uranium concentration in raffinate stream of Purex
process during reprocessing of spent nuclear fuel has been developed. It works on the principle of detection of fluorescence
of uranyl complex formed by using fluorescence enhancing reagent like sodium pyrophosphate. The uranium concentration was
determined in the range of 0–40 ppb and detection limit of 0.2 ppb. The optimum time discrimination is obtained when the uranyl
ion is complexed with sodium pyrophosphate. Need of preconcentration step or separation of uranium from interfering elements
is not an essential step. 相似文献
17.
R. K. Singhal J. Preetha Rupali Karpe P. Hema Ajay Kumar V. M. Joshi A. K. Ranade A. G. Hegde 《Journal of Radioanalytical and Nuclear Chemistry》2009,279(1):301-306
During this work the determination of uranium in the range of μg·L−1 to tens of μg·L−1 was done by alpha-spectrometry after electroplating the aliquots of water sample using (NH4)2SO4 as an electrolyte. In general, the determination of uranium by alpha-spectrometry needs its separation from other transuranics
specially thorium. The process described here does not involve any sample digestion and radiochemical separation of uranium
from other transuranics. In this method an aliquot (1 to 3 mL) of the sample was dried and dissolve in (NH4)2SO4 and thereafter the sample was electroplated on a stainless steel (SS) planchet by using an electrochemical cell of special
design. The proposed techniques have a distinct advantage over the determination of uranium by adsorptive stripping voltammetry
(AdSV) in which uranium-chloranilic (2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone) acid complex was used for concentrating
the uranium from the solution. Since in the case of AdSv, the determination of uranium was not possible for samples having
dissolved organic carbon (DOC) more than 15 mg·L−1 and Cl− concentration is in the range of 40,000 μ·g−1. In the case of spike experiments with 232U the recovery was observed in the range of 90–95% in aqueous medium having higher concentration of Cl− and DOC as indicated above. 相似文献
18.
The paper describes a research of possible application of UTEVA and TRU resins and anion exchanger AMBERLITE CG-400 in nitrate form for the isolation of uranium and thorium from natural samples. The results of determination of distribution coefficient have shown that uranium and thorium bind on TRU and UTEVA resins from the solutions of nitric and hydrochloric acids, and binding strength increases proportionally to increase the concentration of acids. Uranium and thorium bind rather strongly to TRU resin from the nitric acid in concentration ranging from 0.5 to 5 mol L−1, while large quantities of other ions present in the sample do not influence on the binding strength. Due to the difference in binding strength in HCl and HNO3 respectively, uranium and thorium can be easily separated from each other on the columns filled with TRU resin. Furthermore, thorium binds to anion exchanger in nitrate form from alcohol solutions of nitric acid very strongly, while uranium does not, so they can be easily separated. Based on these results, we have created the procedures of preconcentration and separation of uranium and thorium from the soil, drinking water and seawater samples by using TRU and UTEVA resins and strong base anion exchangers in nitrate form. In one of the procedures, uranium and thorium bind directly from the samples of drinking water and seawater on the column filled with TRU resin from 0.5 mol L−1 HNO3 in a water sample. After binding, thorium is separated from uranium with 0.5 mol L−1 HCl, and uranium is eluted with deionised water. By applying the described procedure, it is possible to achieve the concentration factor of over 1000 for the column filled with 1 g of resin and splashed with 2 L of the sample. Spectrophotometric determination with Arsenazo III, with this concentration factor results in detection limits below 1 μg L−1 for uranium and thorium. In the second procedure, uranium and thorium are isolated from the soil samples with TRU resin, while they are separated from each other on the column filled with anion exchanger in alcohol solutions. Anion exchanger combined with alcohol solutions enables isolation of thorium from soil samples and its separation from a wide range of elements, as well as spectrophotometric determination, ICP-MS determination, and other determination techniques. 相似文献
19.
Hyoe Takata Tatsuo Aono Keiko Tagami Shigeo Uchida 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(3):795-799
For safety assessments of geological repositories of nuclear waste, understanding of uranium (U) fate in estuarine areas is
important because U chemical behavior in the areas is expected to be complex. Environmental transfer parameters such as sediment–water
distribution coefficients (K
d) and concentration ratios (CRs) for marine organisms are useful in mathematical models for the assessment. However, due to
its low concentration in estuarine water, K
d and CF data for U are scarce. Thus we studied a rapid method for separation and concentration of U from estuarine water samples
using NOBIAS-CHELATE PA1 resin columns followed by inductively coupled plasma mass spectrometry (ICP-MS) for U measurement.
Chemical recovery was about 100% at pH of 5.7 ± 0.1 from the water samples and alkali and alkaline earth metals were removed.
The method was used to measure U concentrations in estuarine water samples collected at eight Japanese estuarine areas; they
ranged from 0.1 to 3.8 μg L−1. We also measured U concentrations in sediment and marine organism samples by ICP-MS after acid digestion. Using these values,
we observed K
d (range: 39–284 L kg−1) and CRs (0.86–52 L kg−1 for macroalgae, 0.087–15 L kg−1 for crustaceans, and 0.52–93 L kg−1 for molluscs). 相似文献
20.
A method is presented for the simultaneous determination of chromium, iron, cobalt and zinc in samples of uranium concentrates, oxides and metallic uranium by neutron-activation analysis. The method involves adequate decontamination of gross fission product activities by adsorption on silica gel, removal of uranium by solvent extraction, separation of most carrier-free rare-earth activities by coprecipitation with aluminium chloride, and, finally, fractional separation of the elements concerned by ion-exchange chromatography. The method can assay ppm of such elements in limited quantities of samples by scintillation gamma-ray spectrometric analysis with a reproducibility of 10-15%. 相似文献