ASTM C1254-2018 Standard Test Method for Determination of Uranium in Mineral Acids by X-Ray Fluorescence.pdf

1、Designation: C1254 13C1254 18Standard Test Method forDetermination of Uranium in Mineral Acids by X-RayFluorescence1This standard is issued under the fixed designation C1254; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year

2、 of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the steps necessary for the preparation and analysis by X-ray fluorescence (XRF) of minera

3、l acidsolutions containing uranium.1.2 This test method is valid for those solutions containing 0.05 to 20 g uranium/L as presented to the spectrometer. Higherconcentrations may be covered by appropriate dilutions.1.3 The values stated in SI units are to be regarded as the standard.1.4 This standard

4、 does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use. Spec

5、ific precautionary statements are given in Section 9 and Note 1.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendation

6、s issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C859 Terminology Relating to Nuclear MaterialsC982 Guide for Selecting Components for Energy-Dispersive X-Ray Fluorescence (XRF) Systems (Withdrawn 2008)3C1118 Guide for Sel

7、ecting Components for Wavelength-Dispersive X-Ray Fluorescence (XRF) Systems (Withdrawn 2011)3D1193 Specification for Reagent WaterE135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials2.2 Other Document:ANSI/HPS N43.22001 Radiation Safety for X-ray Diffraction and

8、 Fluorescence Analysis Equipment33. Terminology3.1 Definitions:3.1.1 See Terminologies E135 and C859 for definitions of terms applicable to this test method.4. Summary of Test Method4.1 Solution standards containing 0.025 g uranium/L to 20 g uranium/L and an appropriate internal standard (usually ei

9、theryttrium or strontium), unless a scatter line is used in lieu of, are placed in a liquid sample holder of an X-ray spectrometer andexposed to an X-ray beam capable of exciting the uranium L-alpha emission line and the appropriate emission line for the internalstandard (usually the K-alpha line).

10、The intensities generated are measured by an appropriate detector. The intensity ratio valuesobtained from this data are used to calibrate the X-ray analyzer.5. Significance and Use5.1 This test method is applicable to aqueous solutions of uranium containing 0.05 to 20 g uranium per litre of solutio

11、npresented to the spectrometer.1 This test method is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of Test.Current edition approved Jan. 1, 2013Oct. 1, 2018. Published January 2013November 2018. Originally approv

12、ed in 1993. Last previous edition approved in 19992013as C1254 99 (2005).C1254 13. DOI: 10.1520/C1254-13.10.1520/C1254-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refe

13、r to the standards Document Summary page on the ASTM website.3 Available from the Health Physics Society, McLean, Virginia, 22101.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. B

14、ecauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 10

15、0 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.2 Either wavelength-dispersive or energy-dispersive X-ray fluorescence systems may be used provided the softwareaccompanying the system is able to accommodate the use of internal standards.6. Interferences6.1 This te

16、st method requires the use of an appropriate internal standard. Care must be taken to ascertain that samples analyzedby this test method do not contain the internal standard element or that this contamination has been corrected for mathematicallywhenever present. Such corrections are not addressed i

17、n this test method.6.2 Alternatively a scatter line may be used as internal standard in which case the preparation of internal standard solutions andsubsequent doping of samples and calibration standards is unnecessary.46.3 Sample must not contain significant concentration of any elements that have

18、mass absorption edges that fall between theenergies of the uranium L-alpha line and the internal standard line.6.4 Care must also be taken that the choice of internal standard and sample medium are compatible; that is, do not use yttriumwith solutions containing HF or strontium with those having H2S

19、O4.7. Apparatus7.1 X-Ray SpectrometerSee Guide C982 or Guide C1118 for the selection of the X-ray spectrometer. This test method is validfor either energy-dispersive or wavelength-dispersive systems.7.2 Sample Cups:7.2.1 Prepare liquid sample cups for the X-ray spectrometer as described by the manuf

20、acturer. Vented, disposable sample cupswith snap-on caps are satisfactory for most such analyses; such cups decrease the likelihood of contamination between samples.7.2.2 Polyester, polyethylene, and polypropylene films have been used successfully as the film window for such cups. Testsshould be per

21、formed to determine the serviceability of any film chosen before insertion into the instrument.7.3 Solution DispenserThe dispenser for the internal standard solution should be capable of reproducibly dispensing theinternal standard to a level of 0.5 % relative standard deviation of the volume dispen

22、sed.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee of Analytical Reagents of the American Chemical Society where suchspecifications are avail

23、able.5 Other grades may be used provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.8.2 Purity of WaterUnless otherwise indicated, references to water shall mean reagent water conforming to Specificatio

24、nD1193.8.3 Ferric Nitrate, Fe(NO3)39H2O.8.4 Nitric Acid, HNO3, concentrated (70 %).8.5 Strontium Carbonate, SrCO3.8.6 Uranium Oxide, U3O8, NBL CRM-1296 (or equivalent).8.7 Yttrium Oxide, Y2O3.9. Technical Precautions9.1 XRF equipment analyzes by the interaction of ionizing radiation with the sample.

25、Applicable safety regulations and standardoperating procedures must be reviewed prior to the use of such equipment.All modern XRF spectrometers are equipped with safetyinterlocks to prevent accidental penetration of the X-ray beam by the user. Do NOT override these interlocks without propertraining,

26、 or a second knowledgeable person present during such operation. (See ANSI/HPS N43.22001.)9.2 Instrument performance may be influenced by environmental factors such as heat, vibration, humidity, dust, stray electronicnoise, and line voltage stability. These factors and performance characteristics sh

27、ould be reviewed prior to use of this standard.10. Preparation of Apparatus10.1 Chamber EnvironmentThe standards and samples used in this test method are corrosive liquids. Some fumes will beemitted from the sample cups. These fumes may be detrimental to the spectrometer chamber. It is desirable to

28、flush this chamber4 Andermann, George, and Kemp, J. W., “Scattered X-Rays as Internal Standards in X-Ray Spectroscopy,” Analytical Chemistry, Vol. 20(8), 1958.5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of r

29、eagents not listed bythe American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.6 Available from the U.S. Department of Energy, New Br

30、unswick Laboratory, D350, 9800 South Cass Avenue, Argonne, IL 60439, Attn: Reference Material Sales.C1254 182with an appropriate gas (for example, helium and nitrogen) before and during analysis. Some X-ray spectrometers control thechange of sample chamber atmosphere (air, vacuum, helium, nitrogen)

31、automatically through the software; in others, it must bedone manually. Follow the instrument manufacturers recommendations to achieve the inert gas environment.NOTE 1Caution:Allow sufficient stabilization time before analysis. Care must be taken to ensure that a vacuum environment is not chosen wit

32、h liquidsamples.10.2 X-Ray Power SupplyIf the power to the X-ray tube is not controlled by the instrument software, set the propercombination of voltage and current for the instrument in use. These settings must be determined by the user for his instrument andchoice of X-ray tube. Allow sufficient s

33、tabilization time prior to analysis.11. Calibration and Standardization11.1 Internal Standard Solution (25.0 g/L):11.1.1 Weigh 25 g of the chosen internal standard compound into an 800-mL beaker. Cover with water.Add concentrated nitricacid slowly. For yttrium oxide the reaction will be slow and may

34、 require heating. For strontium carbonate, the reaction will bevigorous.11.1.2 Heat on a hot plate if necessary to complete the dissolution.11.1.3 Cool the solution to room temperature, and transfer to a 1000-mL volumetric flask. (Filter the solution if necessary.)Dilute to volume with water and mix

35、 thoroughly.11.2 Impurity Stock Solution (Optional):11.2.1 Weigh 50 g of reagent grade ferric nitrate, Fe(NO3)39H2O, into a 600-mL beaker.11.2.2 Dissolve the crystals in 200 mL of water and 50 mL of concentrated nitric acid.11.2.3 When cool, transfer the solution to a 1000-mL volumetric flask and di

36、lute to volume with water.11.3 Uranium Calibration Standards:11.3.1 Prepare a uranium standard for each concentration level by weighing into a 150-mLbeaker the amounts of uranium oxidegiven in Table 1.11.3.2 Dissolve the oxide in 25 mL of water and 25 mL concentrated nitric acid. Heat on a hot plate

37、, if necessary to completethe dissolution.11.3.3 When cool, transfer each solution to a properly labeled 100-mL volumetric flask. Add the amount of internal standardsolution and impurity solution (if desired) indicated in Table 1 to each volumetric flask.NOTE 2The internal standard solution may be a

38、dded using a dispensing pipet if desired. However, care must be taken to ensure that no adjustmentto the dispenser is made between use for standards and use for samples.11.3.4 Dilute to volume with water and mix thoroughly.11.4 Instrument Calibration:11.4.1 Follow manufacturers instructions for the

39、instrument in use to obtain intensity data for the uranium L-alpha and theinternal standard line or scatter line for each standard.TABLE 1 Uranium Calibration StandardsConcentration,(g/L)Weight U3O8(CRM-129)AInternalStandard,(mL)Impurity Solution,(mL)AFinal Volume,(mL)0.025 0.00295 4 5 1000.050 0.00

40、590 4 1000.100 0.01180 4 5 1000.500 0.05898 4 1001.000 0.11796 4 5 1001.250 0.14745 4 1001.500 0.17694 4 5 1001.750 0.20644 4 1002.00 0.23593 4 5 1004.00 0.47185 4 1006.00 0.70778 4 5 1008.00 0.94370 4 10010.00 1.17963 4 10 10012.00 1.41556 4 10014.00 1.65148 4 10 10016.00 1.88741 4 10018.00 2.12333

41、 4 10 10020.00 2.35926 4 100A Weights will need to be adjusted for the purity of the uranium reference materialused. See the certification accompanying the material. Weights indicated are forNBL CRM-129 (no longer available; use NBL CRM-129 or equivalent). Use of theimpurity solution is optional.C12

42、54 18311.4.2 Exercise care that the analytical conditions determined appropriate for the instrument in use are documented, or recorded,in sufficient detail that these may be reproduced in subsequent runs and when analyzing the samples.11.4.3 Calculate the uranium/internal standard ratios from the da

43、ta obtained in 11.4.1. Calculate a calibration curve using theseratios. Currently available instrument software should need curve equation. A complete discussion of the mathematical derivationof the available equations is outside the scope of this procedure. Explanations of correction models and int

44、erelement effects arefound in several sources.7,812. Procedure12.1 Sample Preparation:12.1.1 Shake the sample and pipet an appropriate aliquot into a tared 50-mL volumetric flask.NOTE 3Some estimate of the approximate g U/L will be necessary to determine the appropriate dilution. This may be obtaine

45、d by gamma countingof the incoming sample, prior knowledge of the origin of the sample or some other scheme devised by the user. Such schemes are outside the scope ofthis standard.12.1.2 Obtain the gross weight of the sample and flask. (If an answer on a weight basis is not desired, this may be omit

46、ted.)12.1.3 Add 2 mL of the internal standard solution; dilute to volume with water and mix thoroughly.12.2 Counting the Sample:12.2.1 Set the X-ray spectrometer to the conditions noted in 11.4.1. If the analytical conditions are controlled by computer, startthe computer according to manufacturers i

47、nstructions for the software in use.12.2.2 Shake each flask to mix thoroughly. Fill the liquid sample cup with the appropriate amount of sample (cup and volumeboth consistent with that used in 11.4.2 for calibration).12.2.3 Following manufacturers instrumental instructions, obtain intensities for th

48、e uranium L-alpha line and the internalstandard or scatter line.12.2.4 Calculate the uranium concentration in the flask using the appropriate equation.NOTE 4Additional factors, such as volume, weight, isotopic correction, secondary dilutions, may be included in the utilized equations to obtain resul

49、tson the proper basis for the users application.7 Bertin, Eugene P., Introduction to X-Ray Spectrometric Analysis, Plenum Press, New York and London, 1978.8 Tertian, R., and Claisse, F., Principles of Quantitative X-Ray Fluorescence Analysis, Heyden and Son, London, Philadelphia, and Rheine, 1982.TABLE 2 Data for Solution #1NOTE 1Uranium in Mineral Acid by XRFTheoretical value 0.03916 g U/g solution.0.0391780.0396690.0395740.0394800.0389240.0393560.0389520.0389760.0394050.0389520.0393130.0389250.0391260.0391380.0392130.0393560.0393310.0394180.0392410.039190