ASTM_C_1416_-_04_2009.pdf

Designation:C141604(Reapproved 2009)StandardTest Method forUranium Analysis Waste Water by X-ray Fluorescence1This standard is issued under the fixed designation C1416;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year 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 applies for the determination of traceuranium content in waste water.It covers concentrations of Ubetween 0.05 mg/L and 2 mg/L.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Summary of Test Method2.1 Uranyl cations are collected on ion exchange cellulosephosphate papers by circulating the water to be analysedthrough the paper with a peristaltic pump.After drying,theuranium is determined using X-ray fluorescence.3.Significance and Use3.1 Uranium production facilities must control trace ura-nium content in their waste waters.3.2 Colorimetric and fluorimetric methods have been devel-oped but require a tedious separation of interfering elements.Trace uranium can also be determined by ICP-MS but not allwater matrices are adapted(for example,waters with high saltcontent).Direct X-ray fluorescence can be done on the liquidbut with a detection limit of;5 mg/L3.3 X-ray fluorescence after collection of uranium offers theadvantages to reach low detection limits(0.05 mg/L)and toavoid handling a liquid in the spectrometer.4.Interferences4.1 Uranium is collected on the paper by the precipitation ofa uranyl phosphate complex at pH=2.5.Other cations(forexample,Pb,Bi,Sn,Zr,As,.)having a low phosphatesolubility at low pH are also collected and will interfere only atlarge concentration(the maximum capacity of the paper is 8.5eq/cm2).As an example,for a solution containing 1 mg/L ofeach Pb,Bi,Sn,Zr,andAs,and 0.3 mg/L of uranium,a bias of5%was detected on the uranium content.See also 9.2.4.2 Other elements such as Fe,Cu,Ni,Al,Cr.,which havea higher phosphate solubility at low pH were found to have noeffect even at concentration of 10 mg/L.4.3 The excess of anions forming strong complexes with theuranyl cation can also bias the uranium determination.As anexample,for a solution containing 100 mg/L of F(added asNaF)and 0.3 mg/L of uranium,a bias of 30%was found onthe uranium determination.On the contrary,anions formingweak uranyl complexes(such as SO42-,Cl.)were seen tohave no effect even at concentration of several g/L.5.Apparatus5.1 Wavelength dispersive X-ray fluorescence spectrometerequipped with a LiF(200)crystal,a molybdenum,tungsten orrhodium target tube and a scintillation detector.NOTE1Energy dispersive instruments may be applicable.5.2 Peristaltic pump capable of achieving a flow rate of 50mL/min.5.3 A filtration apparatus which comprises a filter holder,a250 mL flask located on top of the filter,and a pipe on bottomof the filter connected to the peristaltic pump.The sample to beanalyzed is poured in the flask,flows through the phosphatefilter and the liquid collected on bottom is brought back to theflask through the peristaltic pump.5.4 Pipet0.2 mL,1 mL,5 mL,10 mL,20 mL.25.5 pH-meter.5.6 100 mL volumetric flasks.6.Reagents and Materials6.1 Purity of MaterialsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents conform to the specification of the Committee onAnalytical Reagents of the American Chemical Society where1This test method is under the jurisdiction ofASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods ofTest.Current edition approved June 1,2009.Published July 2009.Originally approvedin 1999.Last previous edition approved in 2004 as C1416 04.DOI:10.1520/C1416-04R09.2Dilution detailed in 6.5 and 6.7 may also be done by weight.In that case,pipetsare not necessary.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesNOTICE:This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International(www.astm.org)for the latest information1 such specifications are available.3Other grades may be usedprovided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterConventional distilled water is foundacceptable for this analysis.6.3 Phosphate paper filters.46.4 Concentrated hydrochloric acid,12.1 M(sp gr 1.187).6.5 Diluted hydrochloric acid,5 M.Add 41 mL of concen-trated hydrochloric acid(