ASTM E536-2005 Standard Test Methods for Chemical Analysis of Zinc and Zinc Alloys《锌和锌合金化学分析的标准试验方法》.pdf

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1、Designation: E 536 05Standard Test Methods forChemical Analysis of Zinc and Zinc Alloys1This standard is issued under the fixed designation E 536; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number

2、in parentheses indicates the year of last reapproval. Asuperscript epsilon (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.Note Changes were made throughout and the year date changed on July 25,

3、2005.1. Scope1.1 These test methods cover the chemical analysis of zincand zinc alloys having chemical compositions within thefollowing limits:Element Concentration Range, %Aluminum 0.005 to 4.5Cadmium 0.001 to 0.5Copper 0.001 to 1.3Iron 0.001 to 0.1Lead 0.001 to 1.6Magnesium 0.001 to 0.1Tin 0.001 t

4、o 0.11.2 These test methods appear as follows:SectionsAluminum by the EDTA Titrimetric Method (0.5 to 4.5 %) 9-16Aluminum, Cadmium, Copper, Iron, Lead, and Magnesium by theAtomic Absorption Method 17-271.3 This standard does not purport to address all of thesafety concerns, if any, associated with i

5、ts 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 6.2. Referenced Documents2.1 ASTM Standards:2D 1193 Spec

6、ification for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical Analysis of MetalsE55 Practice for Sampling Wrought Nonferrous Metals andAlloys for Determination o

7、f Chemical CompositionE60 Practice for Photometric and SpectrophotometricMethods for Chemical Analysis of MetalsE88 Practice for Sampling Nonferrous Metals and Alloysin Cast Form for Determination of Chemical CompositionE 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related

8、MaterialsE 173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of MetalsE 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3. Terminology3.1 For definitions of terms used in this test method, refer toTerminology E

9、 135.4. Significance and Use4.1 These test methods for the chemical analysis of zincmetals and alloys are primarily intended as referee methods totest such materials for compliance with compositional specifi-cations. It is assumed that all who use these test methods willbe trained analysts capable o

10、f performing common laboratoryprocedures skillfully and safely. It is expected that work will beperformed in a properly equipped laboratory.5. Apparatus, Reagents, and Photometric Practice5.1 Apparatus and reagents required for each determinationare listed in separate sections of each test method. T

11、heapparatus, standard solutions, and reagents shall conform to therequirements prescribed in Practices E50. Photometers shallconform to the requirements prescribed in Practice E60.1These test methods are under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores and Related

12、 Materials and are the directresponsibility of Subcommittee E01.05 on Cu, Pb, Zn, Cd, Sn, Be, their Alloys andRelated Metals.Current edition approved July 25, 2005. Published July 2005. Originallyapproved in 1975. Last previous edition approved in 2004 as E 536 04a.2For referenced ASTM standards, vi

13、sit 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-

14、2959, United States.6. Safety Hazards6.1 For precautions to be observed in the use of certainreagents in these test methods, refer to Practices E50.7. Sampling7.1 For procedures for sampling the material, refer toPractices E55andE88.8. Rounding Calculated Values8.1 Calculated values shall be rounded

15、 to the desired num-ber of places as directed in Practice E29.9. Interlaboratory Studies9.1 These test methods have been evaluated in accordancewith Practice E 173, unless otherwise noted in the precisionsection.ALUMINUM BY THE EDTA TITRIMETRIC METHOD10. Scope10.1 This test method covers the determi

16、nation of aluminumin concentrations from 0.5 to 4.5 %.11. Summary of Test Method11.1 After dissolution of the sample in hydrochloric acid,the solution is buffered and disodium (ethylenedinitrilo) tet-raacetate (EDTA) is added. The excess EDTA is titrated withstandard zinc solution. Sodium fluoride i

17、s added to decomposethe aluminum-EDTA complex, and the released EDTA istitrated with standard zinc solution.12. Interferences12.1 The elements ordinarily present do not interfere if theirconcentrations are under the maximum limits shown in 1.1.13. Apparatus13.1 Magnetic Stirrer, with stirring bar co

18、vered with TFE-fluorocarbon.14. Reagents14.1 Bromcresol Green Indicator Solution (0.4 g/L)Dissolve 0.04 g of bromcresol green in 6 mL of 0.01 N NaOHsolution and dilute to 100 mL.14.2 EDTA Solution (90 g/L)Dissolve 90.0 g of disodium(ethylenedinitrilo) tetraacetate dihydrate in about 800 mL ofwarm wa

19、ter. Cool and dilute to 1 L.14.3 Methyl Red Indicator Solution (0.4 g/L)Dissolve 0.1g of methyl red in 3.72 mL of 0.1 N NaOH solution and diluteto 250 mL with water. Filter if necessary.14.4 Sodium Acetate Buffer Solution (320 g/L)Dissolve320 g of sodium acetate trihydrate in about 800 mL of wateran

20、d filter. Using a pH meter, adjust the pH of the solution to 5.56 0.1 with NaOH solution or acetic acid and dilute to 1 L.14.5 Sodium Fluoride Solution (Saturated)Dissolve 60 gof sodium fluoride (NaF) in 1 Lof boiling water. Cool and filterthrough a coarse paper. Store in a polyethylene bottle.14.6

21、Xylenol Orange Indicator Solution (10 g/L)Dissolve0.250 g of xylenol orange in 25 mL of water. Do not use asolution that has stood more than 1 month.14.7 Zinc Standard Solution (1 mL = 1.00 mg Al)Dissolve 2.423 g of zinc metal (purity: 99.99 % min) in 20 mLof HCl. Dilute to 100 mL. Add 3 drops of me

22、thyl red solutionand neutralize with NH4OH. Add HCl until the color changesto red. Transfer to a 1-L volumetric flask, dilute to volume, andmix.14.8 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water as definedby Type II of Specification D 1193.15.

23、 Procedure15.1 Select and weigh a sample to the nearest 1 mg, inaccordance with the following:.Aluminum,%SampleWeight, gAliquot,mLEDTAAddition, mL0.5 to 1.5 10.0 50 165 to 1681.5 to 2.5 6.0 50 103 to 1062.5to4.5 5.0 40 72to75Transfer the sample to a 400-mL beaker, and cover.15.2 Add 100 mL of HCl (1

24、+1). Heat until dissolution iscomplete and boil for 2 to 3 min. If a residue remains, add 1mL of H2O2and boil the solution for at least 5 min to destroyexcess H2O2and expel free chlorine.NOTE 1Excess peroxide and free chlorine must be removed toprevent fading of the indicators.15.3 Transfer the solu

25、tion to a 200-mL volumetric flask,dilute to volume, and mix.15.4 Using a pipet, transfer the aliquot specified in 15.1 to a500-mL wide-mouth Erlenmeyer flask.15.5 Add the volume of EDTA solution specified in 15.1and dilute to 200 mL.NOTE 2The amount of EDTAadded must be sufficient to complex thezinc

26、 and aluminum with some excess. The amount of EDTA required is5.7 mg for each milligram of zinc and 14.0 mg for each milligram ofaluminum.15.6 Add 5 or 6 drops of methyl red solution. Add NH4OHuntil the color changes to orange.15.7 Add 25 mL of sodium acetate buffer solution and boilfor 3 to 5 min.

27、Cool in a water bath.15.8 Add 4 drops of xylenol orange solution and 5 or 6drops of bromcresol green solution.15.9 Using a TFE-fluorocarbon-covered stirring bar and amagnetic stirrer, stir the solution while adding standard zincsolution from a 50-mL buret to complex the excess EDTA.Addthe solution d

28、ropwise as the end point is approached. Continuethe titration until the color changes from green to red. Refill theburet.15.10 Add 25 mL of NaF solution and boil for 3 to 5 min.Cool in a water bath.15.11 Titrate with standard zinc solution as directed in 15.9and record the volume to the nearest 0.01

29、 mL.16. Calculation16.1 Calculate the percentage of aluminum as follows:Aluminum, % 5 AB/C! 3 100 (1)E536052where:A = standard zinc solution used in 15.11, mL,B = aluminum equivalent of the standard zinc solution,g/mL, andC = sample represented in the aliquot taken, g.17. Precision and Bias17.1 Prec

30、isionEight laboratories cooperated in testingthis test method and obtained the results summarized in Table1.17.2 BiasNo information concerning the accuracy of thistest method is available because certified reference materialssuitable for chemical test methods were not available when theinterlaborato

31、ry test was performed. The analyst is urged to usean accepted reference material, if available, to determine thatthe accuracy of results is satisfactory.17.3 Practice E 173 has been replaced by Practice E 1601.The reproducibility Index R2, corresponds to the Reproducibil-ity Index R of Practice E 16

32、01. Likewise the RepeatabilityIndex R1of Practice E 173 corresponds to the RepeatabilityIndex r of Practice E 1601.ALUMINUM, CADMIUM, COPPER, IRON, LEAD,AND MAGNESIUM BY THE ATOMIC ABSORPTIONMETHOD18. Scope18.1 This test method covers the determination of aluminumin concentrations from 0.002 to 0.5

33、%, cadmium from 0.001 to0.5 %, copper from 0.001 to 1.3 %, iron from 0.003 to 0.1 %,lead from 0.002 to 1.6 %, and magnesium from 0.001 to 0.1 %.19. Summary of Test Method19.1 A hydrochloric acid solution of the sample is aspiratedinto the flame of an atomic absorption spectrophotometer. Theabsorptio

34、n of the resonance line energy from the spectrum ofeach element is measured and compared with that of calibra-tion solutions of the same element. The wavelengths of thespectral lines and other method parameters are tabulated in22.1 for each element.20. Concentration Range20.1 The concentration range

35、 for each element must bedetermined experimentally, because the optimum range willdepend upon the individual instrument. If the optimum con-centration range and instrument parameters have been deter-mined, proceed in accordance with in Section 26; otherwise,determine the concentration range in accor

36、dance with inSection 22.21. Interferences21.1 The elements ordinarily present do not interfere if theirconcentrations are under the maximum limits shown in 1.1.22. Apparatus22.1 Atomic Absorption Spectrophotometer, equipped witha premix burner, with facilities for using the oxidizer-fuelcombinations

37、 listed in the following table. Use hollow-cathodelamps operated in accordance with manufacturers recommen-dations as sources for the spectral lines. The instrument may beconsidered suitable for this test method if a concentration rangecan be found for which the minimum response, calibrationvariabil

38、ity, and reference variability tabulated in the followingtable can be met:ElementSpectralLine, nmOxidizer-FuelStandardSolutionMinimumResponse,UnitsCalibra-tion Vari-ability, %ReferenceVariabil-ity, %Aluminum 309.2 N2OC2H2“A”“B”9253.51.02.00.5Cadmium 228.8 AirC2H2. 50 0.8 0.4Copper 324.7 AirC2H2“A”“B

39、”15502.00.80.80.4Iron 248.3 AirC2H2“A”“B”15252.01.01.00.5Lead 217.0 AirC2H2“A”“B”10302.01.01.50.4Magnesium 285.2 N2OC2H2. 20 1.5 0.822.1.1 Prepare the dilute standard solution, reference, andcalibration solutions in accordance with Section 24. Refer tothe table in 24.1 for suggested initial concentr

40、ations.22.1.2 Prepare the instrument for use in accordance with in26.1. Measure the instrument response while aspirating thereference solution, the lowest, and the two highest calibrationsolutions, performing the measurements in accordance with26.2.2 and 26.2.3.22.1.3 Minimum ResponseCalculate the d

41、ifference be-tween the readings of the two highest of the five equally spacedcalibration solutions. This difference must be equal to orgreater than the number of scale units specified in the table in22.1. For purposes of this test method, the scale unit is definedas one in the least significant digi

42、t of the scale reading of themost concentrated calibration solution.22.1.4 Curve LinearityCalculate the difference betweenthe scale readings of the reference solution and the lowest ofthe five equally spaced calibration solutions. If necessary,convert this difference and the difference calculated in

43、 22.1.3 toabsorbance units. Divide the difference for the highest intervalby that for the lowest interval. This ratio must be equal to orgreater than 0.70.22.1.5 If the instrument meets or surpasses the minimumresponse and curve linearity criteria, the initial concentrationrange may be considered su

44、itable. In this case, proceed inaccordance with 22.1.7; otherwise, proceed as follows:22.1.6 If the minimum response is not achieved, prepareanother dilute standard solution to provide a higher concentra-tion range, and repeat 22.1.1-22.1.4. If the calibration curvedoes not meet the linearity criter

45、ion, prepare another dilutestandard solution to provide a lower concentration range, andrepeat 22.1.1-22.1.4. If a concentration range cannot be foundTABLE 1 Statistical InformationTestSpecimenAluminumFound, %Repeatability(R1, E 173)Reproducibility (R2,E 173)G-3 0.3998 0.0190 0.0254H-2 4.04 0.052 0.

46、074E536053for which both criteria can be met, do not use this test methoduntil the performance of the apparatus satisfies the require-ments.22.1.7 Instrument StabilityCalculate the calibration vari-ability and reference variability as follows:Vc5100cS(c 2 c!2n 2 1D12 (2)Vo5100cS(o 2 o!2n 2 1D12(3)wh

47、ere:Vc= calibration variability,c = average absorbance value for the highestcalibration solution,(c c)2= sum of the squares of the n differencesbetween the absorbance readings on thehighest calibration solution and their aver-age,Vo= reference variability relative to c,(o c)2= sum of the squares of

48、the n differencesbetween the absorbance readings on thereference solution and their average, andn = number of readings taken on each solution.22.1.8 If the variability of the readings of the highestcalibration and the reference solutions are not equal to orsmaller than the values specified in 22.1,

49、the stability of theinstrument must be improved before this test method may beused.23. Reagents23.1 Aluminum, Standard Solution (1 mL = 1.00 mg Al)Transfer1gofaluminum (purity: 99.95 % min) to a 250-mLbeaker, cover, and add 50 mL of HCl (1+1). After the reactionhas subsided, add 1 mL of H2O2and boil to completedissolution. Cool and transfer to a 1-L volumetric flask.Add 50mL of HCl, dilute to volume, and mix. Store in a polyethylenebottle.23.2 Cadmium, Standard Solution (1 mL = 1 mg Cd)Transfer1gofcadmium (purity: 99.95 % min) to a 250-mLbeake