| The thesis focuses on the study of the application of two extractionchromatography resins (TEVA resin and UTEVA resin) to the analysis in233UExtraction Process. TEVA resin and UTEVA resin that are endowed with goodspecificity and high efficiency can rapidly isolate trace elements from matrix. The traceelements had been isolated can be accurately determine by Ionized Coupled PlasmaMass Spectrometer (ICP-MS). In the thesis, quantities of research works concerningseparation of uranium in the water waste (1AW) by TEVA resin, fission products in thefeed (1AF) by TEVA and UTEVA resin have been done. The study results indicate thatextraction chromatography resins will have a great advantage of ease of use. Thefollowing investigations with the main achievements have been completed in the thesis.Absorption equilibrium time of thorium and uranium on TEVA resin in nitric acidsystem was studied. The results show that with the system acidity rising the absorbilityof thorium increases and peaks at4or mol/L HNO3, then decreases; the absorption ofuranium was regarded as negligible, and no change after60minutes. To reach completeabsorption equilibrium, shaking time was set as2hours when distribution coefficientof thorium and uranium on TEVA resin was determined.Distribution coefficient (Kd) of thorium and uranium on TEVA resin in nitric acidsystem was studied. The results reveal that with the system acidity rising Kdof thoriumincreases in0.14mol/L nitric acid, while decreases in58mol/L nitric acid; Kdofuranium are no more than13in0.18mol/L nitric acid, marking no absorption on theresin. Therefore,1,2,3,4mol/L nitric acid are elected as eluant, then elution curveswill been drawn.The elution behaviors of uranium and thorium on TEVA resin were studied. Theresults indicate that3and4mol/L nitric acid accompanied by a certain tailing and1mol/L nitric acid been in the wake of plenty of thorium, the elution curves of3and4mol/L nitric acid are fairly flatter than1and2mol/L nitric acid, but the amount ofthorium eluted together with uranium in2mol/L nitric acid is tiny. Hence, discreet consideration would choose2mol/L nitric acid for eluant.Simulated1AW samples were determined. The simulated samples are leachedwith2.5mol/L nitric acid and separated using TEVA resin prior to ICP-MSmeasurements. The chemical recoveries of uranium in the method are97.1%-100.0%(5times), with1mL of stimulated samples and12mL of elution solutions (2mol/LHNO3). The presence of thorium stripped together with uranium doesn’t interfere withthe determination. This method not only circumvents “cumbersome” sample matrixchange, but also employs only one and pretty simple eluant (diluent nitric acid), hencethose simplifications greatly facilitates the separation efficiency than before.The elution behaviors of thorium, uranium and fission products (Cerium,Europium, Gadolinium, Yttrium, Zirconium, Niobium, Ruthenium, Rhodium,Strontium, Caesium) on UTEVA resin column were studied. The results denote thatalmost total fission products (excepting zirconium), a small amount of uranium and20%of uranium in2,3and4mol/L nitric acid are eluted. The eluted thorium interferes withthe determination of fission products.The elution behaviors of thorium, uranium and fission products on TEVA+UTEVA resin tandem cartridges were studied. The results disclose that almost totalfission products (excepting zirconium) in2,3and4mol/L nitric acid exactly likeUTEVA resin single column, but few thorium and uranium are eluted simultaneously.Simulated1AF samples were determined. The simulated samples are leached with3.0mol/L nitric acid and separated using TEVA+UTEVA resin tandem cartriadges, with1mL of simulated samples and5mL of elution solutions (3-7mL). The initial2mL ofelution curves is dead volume, i. e. the volume of TEVA column. After appropriatedilution, the effluents can be directly injected into ICP-MS. The recoveries of fissionproducts excepting gadolinium and zirconium are in the reasonable range, i. e.90-110%. |
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