1、Designation: E 53 02Standard 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 Section 9 and 8.4.2
5、. Referenced Documents2.1 ASTM Standards:E29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2E50 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 Alloys3E 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related Materials3E 173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals3E 255 Practice for Sampling Copper and Copper Alloys forthe Determination of Chem
7、ical Composition3E 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 Method43. Terminology3.1 DefinitionsFor definitions of terms used in t
8、his 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 an
9、d 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 laboratoryprocedures skillfully and safely. It is expected that
10、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 codeposit. If interfering amounts are present,proceed in accord
11、ance with Test Methods E 121.7. Apparatus7.1 Electrodes for Electroanalysis:7.1.1 ElectrodesPlatinum electrodes of the stationary typeare recommended as described in 7.1.2 and 7.1.3, but strictadherence to the exact size and shape of the electrodes is notmandatory. When agitation of the electrolyte
12、is permissible inorder to decrease the time of deposition, one of the types ofrotating forms of electrodes, generally available, may beemployed. The surface of the platinum electrodes should besmooth, clean, and bright to promote uniform deposition andgood adherence. Sandblasting is not recommended.
13、1This 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 Metals.Current edition approved Dec. 10, 2002. Published June 2003
14、. Originallyapproved in 1946. Last previous edition approved in 1998 as E 53 98.2Annual Book of ASTM Standards, Vol 14.02.3Annual Book of ASTM Standards, Vol 03.05.4Annual Book of ASTM Standards, Vol 03.06.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428
15、-2959, United States.7.1.2 CathodesPlatinum cathodes may be formed eitherfrom plain or perforated sheets or from wire gauze, and may beeither open or closed cylinders. Gauze cathodes are recom-mended, and shall be made preferably from 50-mesh gauzewoven from wire approximately 0.21 mm (0.0085 in.) i
16、ndiameter. The cathode should be stiffened by doubling thegauze for about 3 mm at the top and the bottom of the cylinderor by reinforcing the gauze at the top and bottom with aplatinum band or ring. The cylinder should be approximately30 mm in diameter and 50 mm in height. The stem should bemade fro
17、m a platinum alloy wire such as platinum-iridium,platinum-rhodium, or platinum-ruthenium, having a diameterof approximately 1.30 mm. It should be flattened and weldedthe entire length of the gauze. The overall height of the cathodeshould be approximately 130 mm. A cathode of these dimen-sions will h
18、ave a surface area of 135 cm2exclusive of the stem.7.1.3 AnodesPlatinum anodes may be of the spiral typewhen anodic deposits are not being determined, or if thedeposits are small (as in the electrolytic determination of leadwhen it is present in the amounts not over 0.2 %). When usedin analyses wher
19、e both cathodic and anodic plates are to bedetermined, the anodes should be of wire gauze. Spiral anodesshould be made from 1.00-mm or larger platinum wire formedinto a spiral of seven turns having a height of approximately 50mm and a diameter of 12 mm, the overall height beingapproximately 130 mm.
20、A spiral anode of this description willhave a surface area of 9 cm2. Platinum gauze anodes should bemade of the same material and of the same general design asplatinum gauze cathodes. The anode cylinder should be ap-proximately 12 mm in diameter and 50 mm in height and theoverall height of the anode
21、 should be approximately 130 mm.A gauze anode of these dimensions will have a surface area of54 cm2. Both areas are exclusive of the stem.7.2 Atomic Absorption Spectrophotometer:7.2.1 Determine that the atomic absorption spectrophotom-eter is suitable for use as described in Guide E 1024. Thevariabi
22、lity for the highest calibration solution should notexceed 1 %.7.2.2 Operating Parameters:Wavelength 3275 Bandpass About 2 Gas mixture Air-acetyleneFlame type Lean7.2.3 Instrument ResponseAdequate instrument responseis obtained if the difference between the readings of the twohighest of five equally
23、 spaced calibration solutions is sufficientto permit an estimation equivalent to one twentieth of thedifference.7.2.4 Curve LinearityThe upper limit of the useableportion of a calibration curve is normally set such that thedifference between the readings of the two highest of fiveequally spaced cali
24、bration 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 otherwisestated.8. Reagents8.1 Copper, Standard Solution A (1 mL = 1.0 mg Cu)Transfer 1.000 g of ele
25、ctrolytic 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, Standard Solution B (1 mL = 0.20 mg Cu)Using a pipet, transfer 20 mLof copper SolutionAto
26、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, add 210 mL of HNO3.8.4 Potassium Cyanide Solution (100 g/L)Dissolve 100 gof KCN in water and dilute to 1 L. (
27、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 hood. Refer to theapplicable section of Practices E50.)8.5 Sulfamic Acid Solution (100 g/L)Dissolve 10 g ofsulfam
28、ic acid (H(NH2)SO3) 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 with acids that release hydrogen cyanide gas.10. Sampling10.1 For procedures in samplin
29、g 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 producer andconsumer.10.2 For all trace element determinations, care must betaken to limit sample exposure to
30、contaminations, and toremove any contaminations that occur.10.3 Wherever possible, non-metallic tools shall be used toobtain chips (millings, drillings, sawings, nibblings, etc) fromthe sample.10.4 Except for the estimation of oxygen or hydrogen, orwhen analyzing standard reference materials that fo
31、rbid 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, and allowto air-dry. Exercise great care to prevent re-contamination ofthe specimen by metal tools, or from zinc in ru
32、bber stoppers, orchlorides from HCl vapor, etc.10.5 In methods for the determination of impurities incopper, particular care must be taken to prevent specimencontamination by reagents or glassware.10.6 The interior of glassware shall be cleaned immediatelyprior to use by a rinse in HNO3(1+3) followe
33、d 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, intended for tracemetal analysis are recommended but not required.E5302211. Rounding Calculated Values11.1 Ca
34、lculated 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 otherwise noted i
35、n the precision andbias section.13. Procedure13.1 Clean the metal that is to be analyzed in KCN solution.Rinse with water, then alcohol, and air-dry thoroughly atambient temperature.13.2 Transfer5gofthecleaned metal, weighed to thenearest 0.1 mg, to a 400-mLtall-form beaker.Add 45 mLof theH2SO4-HNO3
36、mixture and immediately cover with a closefitting cover glass. Cool as required to prevent the reactionfrom becoming violent. When the reaction has subsided, heatmoderately until dissolution is complete. Continue heating atapproximately 90C until the brown fumes are expelled. Neverboil. Cool slightl
37、y and carefully wash down the cover glass andsides of the beaker. Add 10 mL of sulfamic acid solution, stir,and dilute to approximately 175 to 200 mL.13.3 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
38、the gauze is completelyimmersed. Cover the beaker with a split cover glass.13.4 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 electrolys
39、is untildeposition is essentially complete, 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.13.5 Wash the cathode with
40、 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 ethanol ormethanol. Reserve the electrolyte. Dry at 110C for 3 to 5 min,cool to ambient temperature, and weigh.13.6 Determination of the Residual Copper in the Elec
41、tro-lyte by Atomic Absorption Spectroscopy:13.6.1 Calibration:13.6.1.1 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, a
42、nd 0.005 g of Cu/250 mL.13.6.1.2 Reference SolutionTransfer 20 mL of H2SO4to a250-mL volumetric flask, dilute to volume, and mix.13.6.2 Analysis:13.6.2.1 Test SolutionIf necessary evaporate the spentelectrolyte from 13.5 to below 250 mL and cool. Transfer to a250-mL volumetric flask, dilute to volum
43、e, and mix.13.6.2.2 MeasurementsOptimize the response of the in-strument, take preliminary readings, and complete the analysisand determine the grams of copper in 250 mL by one of theprocedures, graphical, ratio, or single point in accordance withGuide E 1024.14. Calculations14.1 Calculate the weigh
44、t 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.14.2 Calculate the percentage of copper as follows:Copper, % 5 C 1 D!/ E! 3 100 (2)where:C = grams of deposited copper found in 14.1,D = grams of copper in 250 mL o
45、f electrolyte found in13.6.2.2, andE = grams of sample used.15. Precision and Bias515.1 PrecisionSix laboratories cooperated in testing thismethod and obtained the data summarized in Table 1. Theinterlaboratory test was conducted in accordance with PracticeE 173 and calculated using Practice E 1601
46、software.15.2 BiasNo information on the accuracy of this methodis available.16. Keywords16.1 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 1
47、601)1. Copper 99.959 0.008 0.023 0.022. Copper 99.723 0.009 0.051 0.05E53023ASTM 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 advised that determination of the validit
48、y of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comment
49、s are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual
