1、Designation: E 53 07Standard Test Method forDetermination of Copper in Unalloyed Copper byGravimetry1This standard is issued under the fixed designation E 53; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revisio
2、n. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) 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 chemical analysis of
3、 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 address all of
4、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 and Section 9.2
5、. 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 MaterialsE 121 Test Methods for Chemical Ana
6、lysis of Copper-Tellurium AlloysE 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE 173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals3E 255 Practice for Sampling Copper and Copper Alloys forthe Determination of Chemic
7、al CompositionE 1024 Guide for Chemical Analysis of Metals and MetalBearing Ores by Flame Atomic Absorption Spectropho-tometry4E 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3. Terminology3.1 DefinitionsFor definitions of terms used in this
8、testmethod, refer to Terminology E 135.4. 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 isdetermined by atomic absorption spectroscopy.5. Significance and Us
9、e5.1 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 laboratoryprocedures skillfully and safely. It is expected that work
10、 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-deposit. If interfering amounts are present,proceed in accordanc
11、e with Test Methods E 121.7. 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 bright topromote uniform deposition and good adherence. Deviati
12、onsfrom the exact size and shape are allowable. In instances where1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores and Related Materials and is the directresponsibility of Subcommittee E01.05 on Cu, Pb, Zn, Cd, Sn, Be, their Alloys andRelated
13、Metals.Current edition approved Nov. 15, 2007. Published December 2007. Originallyapproved in 1946. Last previous edition approved in 2002 as E 53 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStand
14、ards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Copyright by ASTM Intl (all rights reserved); Tue Jul 15 20:27:46 EDT 2008
15、Downloaded/printed byGuo Dehua (CNIS) pursuant to License Agreement. No further reproductions authorized.it is desirable to decrease the time of deposition and agitationof the electrolyte is permissible, a generally available, rotatingtype of electrode may be employed. Cleaning of the electrodeby sa
16、ndblasting is not recommended.7.1.2 CathodesPlatinum cathodes may be either open orclosed cylinders formed from sheets that are plain or perfo-rated, 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
17、 cathodesshould be reinforced 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-rut
18、henium, having a diameter 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
19、 a spiral type whenanodic 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
20、of approximately 50 mmand 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 descri
21、bed in 7.1.2. Theanode 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
22、that the atomic absorption spectrometer issuitable for use as described in Guide E 1024. 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 ResponseAdequ
23、ate instrument responseis 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 curv
24、e is normally set such 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
25、 unless otherwisestated.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,
26、and mix.8.2 Copper, Standard 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, slowlyadd 300 mL of H2SO4to 750 mL of H2O. Cool to ambienttemperature, and while stirring,
27、 add 210 mL of HNO3.8.4 Potassium Cyanide Solution (100 g/L)Dissolve 100 gof KCN in water and dilute to 1 L. (WarningThe prepara-tion, storage, and use of KCN require care and attention. Avoidinhalation of fumes and exposure of the skin to the chemicaland its solutions. Work in a well-ventilated hoo
28、d. Refer to theapplicable 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 c
29、are, avoidingcontact with acids that release hydrogen cyanide gas.10. Sampling10.1 For procedures in sampling refer to Practice E 255.However, this practice does not supersede any samplingrequirements specified in a specific ASTM material specifica-tion nor preclude a procedure agreed upon by the pr
30、oducer andconsumer.10.2 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 t
31、he sample.10.4 Except for the estimation of oxygen or hydrogen, orwhen analyzing standard reference materials that forbid clean-ing, the chips shall be cleaned prior to weighing a portion foranalysis. Immerse in HNO3(1 + 3), rinse in running waterfollowed by distilled or deionized water and alcohol,
32、 and allowto air-dry. Exercise 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
33、by reagents or glassware.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.
34、 Extra-purity acids, intended for tracemetal analysis are recommended but not required.E53072Copyright by ASTM Intl (all rights reserved); Tue Jul 15 20:27:46 EDT 2008Downloaded/printed byGuo Dehua (CNIS) pursuant to License Agreement. No further reproductions authorized.11. Rounding Calculated Valu
35、es11.1 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. Interlaboratory Studies12.1 This test method has been evaluated in accordancewith Practice E 173 unless otherwis
36、e 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 ofethanol or acetone. Dry at a low temperature (110 C for 3 to5 min), and cool to room temperature in a desic
37、cator.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. Procedure14.1 Clean the metal that is to be analyzed in KCN solution.Rinse with water, then alcohol, and
38、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 closefitting cover glass. Cool as required to prevent the reactionfrom becoming violent. When the reacti
39、on 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 glass andsides of the beaker. Add 10 mL of sulfamic acid solution, stir,and dilute to approximately 175
40、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. Cover the beaker with a split cover glass.14.4 Electrolyze at a current density of about 0.6 A/dm2(Note 1).
41、 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 complete, as indicated by failure toplate on a new surface of the cathode stem when the solutionlevel is r
42、aised.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 beingremoved from the spent solution. Immediately wash succes-sively in two baths of water and two baths of etha
43、nol 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 Spectrometry:14.6.1 Calibration:14.6.1.1 Calibration SolutionsUsing pipets, transfer 5,10, 15, 20, and 25 mL
44、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 Reference SolutionTransfer 20 mL of H2SO4to a250-mL volumetric flask, dilute to volume, and mix.14.6.2 A
45、nalysis: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 MeasurementsOptimize the response of the in-strument, take preliminary readings, and complete the analysisand determi
46、ne the grams of copper in 250 mL by one of theprocedures, graphical, ratio, or single point in accordance withGuide E 1024.15. Calculations15.1 Calculate the weight of deposited copper as follows:Copper, g 5 A 2 B (1)where:A = weight of cathode plus deposited copper, g, andB = weight of cathode, g.1
47、5.2 Calculate the percentage of copper as follows:Copper, % 5 C 1 D!/ E! 3 100 (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 = grams of sample used.16. Precision and Bias516.1 PrecisionSix laboratories cooperated in testing t
48、hismethod and obtained the data summarized in Table 1. Theinterlaboratory test was conducted in accordance with PracticeE 173 and calculated using Practice E 1601 software.16.2 BiasNo certified reference materials suitable fortesting this test method were available when the interlaboratorytesting pr
49、ogram was conducted. The user of this test method isencouraged to employ accepted reference materials, if avail-able, to validate the test method as implemented in a specificlaboratory and to obtain estimates of uncertainty due to bias.17. Keywords17.1 copper; copper concentration5Supporting data are available from ASTM International Headquarters. RequestRR: E01-1089.TABLE 1 Statistical InformationCopperTestSpecimenCopperFound, %Smin(E 1601)R(E 1601)%R(E 1601)1. Copper 99.959 0.008 0.023 0.022. Copper 99.723 0.009 0.051 0.05E53073Copyright by ASTM Intl (
