1、Designation: E53 07 (Reapproved 2013)Standard Test Method forDetermination of Copper in Unalloyed Copper byGravimetry1This standard is issued under the fixed designation E53; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year
2、 of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the chemi
3、cal analysis of copperhaving minimum purity of 99.75 % to 99.95 %.1.2 This test method covers the electrolytic determination ofcopper in chemical, electrolytic, and fire refined copper. In thismethod silver is deposited with the copper, and is reported ascopper.1.3 This standard does not purport to
4、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. Specific precau-tionary statements are given in 8.4
5、and Section 9.2. Referenced Documents2.1 ASTM Standards:2E29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE121 Test Methods fo
6、r Chemical Analysis of Copper-Tellurium Alloys (Withdrawn 2010)3E135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals (Withdrawn1998)3E255 Practice for Sampling Copper and
7、 Copper Alloys forthe Determination of Chemical CompositionE1024 Guide for Chemical Analysis of Metals and MetalBearing Ores by Flame Atomic Absorption Spectropho-tometry (Withdrawn 2004)3E1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3. Term
8、inology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology E135.4. Summary of Test Method4.1 The sample is dissolved in an acid mixture and thecopper is electrolytically deposited and weighed on a taredplatinum cathode. Copper remaining in the electrolyte isdetermin
9、ed by atomic absorption spectroscopy.5. Significance and Use5.1 This test method for the chemical analysis of copper isprimarily intended to test for compliance with compositionalspecifications. It is assumed that all who use this method willbe trained analysts capable of performing common laborator
10、yprocedures skillfully and safely. It is expected that work will beperformed in a properly equipped laboratory.6. Interferences6.1 Elements normally present in refined copper with aminimum purity of 99.85 % do not interfere.6.2 Approximately one-half of any selenium or telluriumpresent will co-depos
11、it. If interfering amounts are present,proceed in accordance with Test Methods E121.7. Apparatus7.1 Electrodes for Electroanalysis:7.1.1 ElectrodesRecommended stationary type platinumelectrodes are described in 7.1.2 and 7.1.3. The surface of theplatinum electrodes should be smooth, clean, and brigh
12、t topromote uniform deposition and good adherence. Deviationsfrom the exact size and shape are allowable. In instances whereit is desirable to decrease the time of deposition and agitation1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and R
13、elated Materials and is the directresponsibility of Subcommittee E01.05 on Cu, Pb, Zn, Cd, Sn, Be, Precious Metals,their Alloys, and Related Metals.Current edition approved Oct. 1, 2013. Published October 2013. Originallyapproved in 1946. Last previous edition approved in 2007 as E53 07. DOI:10.1520
14、/E0053-07R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical st
15、andard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1of the electrolyte is permissible, a generally available, rotatingtype of electrode may be employed. Cleaning of the electrodeby sandblasting is not r
16、ecommended.7.1.2 CathodesPlatinum cathodes may be either open orclosed cylinders formed from sheets that are plain orperforated, or from gauze. Gauze cathodes are recommended;preferably from 50-mesh gauze woven from approximately0.21 mm diameter wire. The top and bottom of gauze cathodesshould be re
17、inforced by doubling the gauze about 3 mm ontoitself, or by the use of platinum bands or rings. The cylindershould be approximately 30 mm in diameter and 50 mm inheight. The stem should be made from a platinum alloy wiresuch as platinum-iridium, platinum-rhodium, or platinum-ruthenium, having a diam
18、eter of approximately 1.3 mm. Itshould be flattened and welded the entire length of the gauze.The overall height of the cathode should be approximately 130mm. A cathode of these dimensions will have a surface area of135 cm2exclusive of the stem.7.1.3 AnodesPlatinum anodes may be a spiral type whenan
19、odic deposits are not being determined, or if the deposits aresmall (as in the electrolytic determination of lead when it ispresent in concentrations below 0.2 %). Spiral anodes shouldbe made from 1.0-mm or larger platinum wire formed into aspiral of seven turns having a height of approximately 50 m
20、mand a diameter of 12 mm with an overall height of approxi-mately 130 mm. A spiral anode of these dimensions will havea surface area of 9 cm2. When both cathode and anode platesare to be determined, the anodes should be made of the samematerial and design as the electrode described in 7.1.2. Theanod
21、e cylinder should be approximately 12 mm in diameterand 50 mm in height and the overall height of the anode shouldbe approximately 130 mm. A gauze anode of these dimensionswill have a surface area of 54 cm2exclusive of the stem.7.2 Atomic Absorption Spectrometer:7.2.1 Determine that the atomic absor
22、ption spectrometer issuitable for use as described in Guide E1024. The variabilityfor the highest calibration solution should not exceed 1 %.7.2.2 Operating Parameters:Wavelength 327.5 nmBandpass About 0.2 nmGas mixture Air-acetyleneFlame type Lean7.2.3 Instrument ResponseAdequate instrument respons
23、eis obtained if the difference between the readings of the twohighest of five equally spaced calibration solutions is sufficientto permit an estimation equivalent to one twentieth of thedifference.7.2.4 Curve LinearityThe upper limit of the usable por-tion of a calibration curve is normally set such
24、 that thedifference between the readings of the two highest of fiveequally spaced calibration solutions is more than 0.7 times thedifference between the lowest of the calibration solutions.Absorbance values are used in this calculation.7.3 Glassware, shall be borosilicate glass unless otherwisestate
25、d.8. Reagents8.1 Copper, Standard Solution A (1 mL = 1.0 mg Cu)Transfer 1.000 g of electrolytic copper (purity: 99.9 % min) toa 250-mL beaker, add 10 mL of HNO3(1 + 1) and cover. Afterdissolution, warm to dispel fumes, cool, transfer to a 1-Lvolumetric flask, dilute to volume, and mix.8.2 Copper, St
26、andard Solution B (1 mL = 0.20 mg Cu)Using a pipet, transfer 20 mLof copper SolutionAto a 100-mLvolumetric flask, dilute to volume, and mix.8.3 Sulfuric-Nitric Acid MixtureWhile stirring, slowly add300 mL of H2SO4to 750 mL of H2O. Cool to ambienttemperature, and while stirring, add 210 mL of HNO3.8.
27、4 Potassium Cyanide Solution (100 g/L)Dissolve 100 gof KCN in water and dilute to 1 L. (WarningThepreparation, storage, and use of KCN require care and atten-tion. Avoid inhalation of fumes and exposure of the skin to thechemical and its solutions. Work in a well-ventilated hood.Refer to the applica
28、ble section of Practices E50.)8.5 Sulfamic Acid Solution (100 g/L)Dissolve 10 g ofsulfamic acid (HNH2SO3) in water and dilute to 100 mL.Prepare fresh daily.9. Hazards9.1 For precautions to be observed in this method, refer toPractices E50.9.2 Cyanides must be disposed of with care, avoidingcontact w
29、ith acids that release hydrogen cyanide gas.10. Sampling10.1 For procedures in sampling refer to Practice E255.However, this practice does not supersede any samplingrequirements specified in a specific ASTM material specifica-tion nor preclude a procedure agreed upon by the producer andconsumer.10.2
30、 For all trace element determinations, care must betaken to limit sample exposure to contaminations, and toremove any contaminations that occur.10.3 Wherever possible, non-metallic tools shall be used toobtain chips (millings, drillings, sawings, nibblings, and soforth) from the sample.10.4 Except f
31、or the estimation of oxygen or hydrogen, orwhen analyzing standard reference materials that forbidcleaning, the chips shall be cleaned prior to weighing a portionfor analysis. Immerse in HNO3(1 + 3), rinse in running waterfollowed by distilled or deionized water and alcohol, and allowto air-dry. Exe
32、rcise great care to prevent re-contamination ofthe specimen by metal tools, or from zinc in rubber stoppers, orchlorides from HCl vapor, and so forth.10.5 In methods for the determination of impurities incopper, particular care must be taken to prevent specimencontamination by reagents or glassware.
33、10.6 The interior of glassware shall be cleaned immediatelyprior to use by a rinse in HNO3(1 + 3) followed by runningwater and by distilled or deionized water, all in an area freefrom HCl fumes.10.7 Reagent acid should be taken from a bottle reserved fortrace metal analysis. Extra-purity acids, inte
34、nded for tracemetal analysis are recommended but not required.E53 07 (2013)211. Rounding Calculated Values11.1 Calculated values shall be rounded to the desirednumber of places, as directed in Practice E29, including as anoption, the special rounding off to a nearest final number offive.12. Interlab
35、oratory Studies12.1 This test method has been evaluated in accordancewith Practice E173 unless otherwise noted in the precision andbias section.13. Preparation of Electrodes13.1 CathodeClean the cathode in hot nitric acid (HNO3),(1 + 1), rinse with distilled water, rinse in two separate baths ofetha
36、nol or acetone. Dry at a low temperature (110 C for 3 to5 min), and cool to room temperature in a desiccator.13.2 AnodeClean in hydrochloric acid (HCl), (1 + 1),rinse with distilled water.13.3 Weigh the cathodes to the nearest 0.1 mg and recordthe weight. The anode does not have to be weighed.14. Pr
37、ocedure14.1 Clean the metal that is to be analyzed in KCN solution.Rinse with water, then alcohol, and air-dry thoroughly atambient temperature.14.2 Transfer5gofthecleaned metal, weighed to thenearest 0.1 mg, to a 400-mLtall-form beaker.Add 45 mLof theH2SO4-HNO3mixture and immediately cover with a c
38、losefitting cover glass. Cool as required to prevent the reactionfrom becoming violent. When the reaction has subsided, heatmoderately until dissolution is complete. Continue heating atapproximately 90 C until the brown fumes are expelled. Neverboil. Cool slightly and carefully wash down the cover g
39、lass andsides of the beaker. Add 10 mL of sulfamic acid solution, stir,and dilute to approximately 175 to 200 mL.14.3 With the electrolyzing current off, position the anodeand the tared cathode, weighed to the nearest 0.1 mg, in thesolution and add water so that the gauze is completelyimmersed. Cove
40、r the beaker with a split cover glass.14.4 Electrolyze at a current density of about 0.6 A/dm2(Note 1). When the solution becomes colorless, wash down thecover glass, electrode stems, and sides of the beaker, add 10mL of sulfamic acid, and continue the electrolysis untildeposition is essentially com
41、plete, as indicated by failure toplate on a new surface of the cathode stem when the solutionlevel is raised.NOTE 1When a current density of 0.6 A/dm2is used, the electrolysisrequires about 16 h and is conveniently carried out overnight.14.5 Wash the cathode with a stream of water as it is beingremo
42、ved from the spent solution. Immediately wash succes-sively in two baths of water and two baths of ethanol ormethanol. Reserve the electrolyte. Dry at 110 C for 3 to 5 min,cool to ambient temperature, and weigh.14.6 Determination of the Residual Copper in the Electro-lyte by Atomic Absorption Spectr
43、ometry:14.6.1 Calibration:14.6.1.1 Calibration SolutionsUsing pipets, transfer 5, 10,15, 20, and 25 mL portions of copper Solution B to 250-mLvolumetric flasks. Add 20 mL of H2SO4(1 + 1), dilute tovolume, and mix. These are equivalent to 0.001, 0.002, 0.003,0.004, and 0.005 g of Cu/250 mL.14.6.1.2 R
44、eference SolutionTransfer 20 mL of H2SO4to a250-mL volumetric flask, dilute to volume, and mix.14.6.2 Analysis:14.6.2.1 Test SolutionIf necessary evaporate the spentelectrolyte from 14.5 to below 250 mL and cool. Transfer to a250-mL volumetric flask, dilute to volume, and mix.14.6.2.2 MeasurementsOp
45、timize the response of theinstrument, take preliminary readings, and complete the analy-sis and determine the grams of copper in 250 mL by one of theprocedures, graphical, ratio, or single point in accordance withGuide E1024.15. Calculations15.1 Calculate the weight of deposited copper as follows:Co
46、pper, g 5 A 2 B (1)where:A = weight of cathode plus deposited copper, g, andB = weight of cathode, g.15.2 Calculate the percentage of copper as follows:Copper, % 5 C1D!/E! 3100 (2)where:C = grams of deposited copper found in 15.1,D = grams of copper in 250 mL of electrolyte found in14.6.2.2, andE =
47、grams of sample used.16. Precision and Bias416.1 PrecisionSix laboratories cooperated in testing thismethod and obtained the data summarized in Table 1. Theinterlaboratory test was conducted in accordance with PracticeE173 and calculated using Practice E1601 software.16.2 BiasNo certified reference
48、materials suitable fortesting this test method were available when the interlaboratorytesting program was conducted. The user of this test method isencouraged to employ accepted reference materials, ifavailable, to validate the test method as implemented in aspecific laboratory and to obtain estimat
49、es of uncertainty due tobias.4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:E01-1089.TABLE 1 Statistical InformationCopperTestSpecimenCopperFound, %Smin(E1601)R(E1601)%R(E1601)1. Copper 99.959 0.008 0.023 0.022. Copper 99.723 0.009 0.051 0.05E53 07 (2013)317. Keywords17.1 copper; copper concentrationASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly adv
