ASTM E536-2015 6966 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: E536 15Standard Test Methods forChemical Analysis of Zinc and Zinc Alloys1This standard is issued under the fixed designation E536; 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

2、 parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 These test methods cover the chemical analysis of zincand

3、zinc alloys having chemical compositions within the limitsof Table 1.TABLE 1 Scope of Mass FractionRanges for Zinc and Zinc AlloysElementConcentrationRange, %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 to 0.11.2 The va

4、lues stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 These test methods appear as follows:SectionsAluminum by the EDTA Titrimetric Method (0.5 to 4.5 %) 1017Aluminum, Cadmium, Copper, Iron, Lead, and Magnesiumby the Atomic Absorption M

5、ethod18281.4 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. Speci

6、fic precau-tionary statements are given in Section 6.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE50 Practices for Apparatus, Reagents, and Safety Consid-erations for

7、 Chemical Analysis of Metals, Ores, andRelated MaterialsE55 Practice for Sampling Wrought Nonferrous Metals andAlloys for Determination of Chemical CompositionE88 Practice for Sampling Nonferrous Metals and Alloys inCast Form for Determination of Chemical CompositionE135 Terminology Relating to Anal

8、ytical Chemistry forMetals, Ores, and Related MaterialsE173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals (Withdrawn1998)3E1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3. Terminology3.1 For definit

9、ions of terms used in this test method, refer toTerminology E135.4. 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

10、who use these test methods willbe trained analysts capable of performing common laboratoryprocedures skillfully and safely. It is expected that work will beperformed in a properly equipped laboratory.5. Apparatus and Reagents5.1 Apparatus and reagents required for each determinationare listed in sep

11、arate sections of each test method. Theapparatus, standard solutions, and reagents shall conform to therequirements prescribed in Practices E50.6. Safety Hazards6.1 For precautions to be observed in the use of certainreagents in these test methods, refer to Practices E50.1These test methods are unde

12、r the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and are the directresponsibility of Subcommittee E01.05 on Cu, Pb, Zn, Cd, Sn, Be, Precious Metals,their Alloys, and Related Metals.Current edition approved June 1, 2015. Published August 2015. Or

13、iginallyapproved in 1975. Last previous edition approved in 2008 as E536 08. DOI:10.1520/E0536-15.2For 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 Docu

14、ment Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. Sampling7.1 For procedures for sampling the material, refer to

15、Practices E55 and E88.8. Rounding Calculated Values8.1 Calculated values shall be rounded to the desired num-ber of places as directed in Practice E29, Rounding Method.9. Interlaboratory Studies9.1 These test methods have been evaluated in accordancewith Practice E173, unless otherwise noted in the

16、precisionsection.ALUMINUM BY THE EDTA TITRIMETRIC METHOD10. Scope10.1 This test method covers the determination of aluminumin concentrations from 0.5 % to 4.5 %.11. Summary of Test Method11.1 After dissolution of the sample in HCl, the solution isbuffered and disodium (ethylenedinitrilo) tetraacetat

17、e (EDTA)is added. The excess EDTA is titrated with standard zincsolution. Sodium fluoride is added to decompose thealuminum-EDTA complex, and the released EDTA is titratedwith standard zinc solution.12. Interferences12.1 The elements ordinarily present do not interfere if theirconcentrations are und

18、er the maximum limits shown in 1.1.13. Apparatus13.1 Magnetic Stirrer, with stirring bar covered with tetra-fluoroethylene polymer (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 sodiumhydroxide (NaOH) solution an

19、d 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 water. Cool and dilute to 1 L.NOTE 1Although it is not critical that this solution be prepared witha 1 L volumetric, doing so makes it more consistent and easier

20、 for theanalyst run to run.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 waterand

21、 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.NOTE 2The analyst is not restricted to using the 0.1 N solution ofNaOH14.5 Sodium Fluoride Solution (Saturated)Dissolve 60 gof sodium fluoride (NaF) in 1 Lof boiling water. Cool a

22、nd filterthrough a coarse paper. Store in a polyethylene bottle.14.6 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 (pur

23、ity: 99.99 % minimum) in20 mL of hydrochloric acid (HCl). Dilute to 100 mL. Add 3drops of methyl red solution and neutralize with ammoniumhydroxide (NH4OH). Add HCl until the color changes to red.Transfer to a 1-L volumetric flask, dilute to volume, and mix.14.8 Purity of WaterUnless otherwise indic

24、ated, referenceto water shall be understood to mean reagent water as definedby Type II of Specification D1193.15. Procedure15.1 Select and weigh a sample to the nearest 1 mg, inaccordance with Table 2.Transfer the sample to a 400-mL beaker, and cover.15.2 Add 100 mL of HCl (1 + 1). Heat until dissol

25、ution iscomplete and boil for 2 minutes to 3 minutes. If a residueremains, add 1 mL of hydrogen peroxide (H2O2) and boil thesolution for at least 5 minutes to destroy excess H2O2and expelfree chlorine.NOTE 3Excess peroxide and free chlorine must be removed to preventfading of the indicators.15.3 Tra

26、nsfer the solution 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 4The amount of EDTA added must be sufficient to

27、complex thezinc 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 five drops or six drops of methyl red solution.AddNH4OH until the color changes to orange.15.7 Add 25 mL of sodium acetate buffer solution

28、 and boilfor 3 minutes to 5 minutes. Cool in a water bath.15.8 Add four drops of xylenol orange solution and fivedrops or six drops 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

29、 buret to complex the excess EDTA.Addthe solution dropwise 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 minutes to5 minutes. Cool in a water bath.TABLE 2 Recommended Sample WeightAlumin

30、um, %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 72to75E536 15215.11 Titrate with standard zinc solution as directed in 15.9and record the volume to the nearest 0.01 mL.16. Calculation16.1 Calculate the percentage of aluminum as

31、follows:Aluminum, % 5 AB/C! 3100 (1)where:A = standard zinc solution used in 15.11, mL;B = aluminum equivalent of the standard zinc solution,g/mL (noted in 14.7); andC = sample represented in the aliquot taken in 15.1,g.17. Precision and Bias17.1 PrecisionEight laboratories cooperated in testing thi

32、stest method and obtained the results summarized in Table 3.17.2 BiasNo information concerning the accuracy of thistest method is available because certified reference materialssuitable for chemical test methods were not available when theinterlaboratory test was performed. The analyst is urged to u

33、sean accepted reference material, if available, to determine thatthe accuracy of results is satisfactory.17.3 Practice E173 has been replaced by Practice E1601.The reproducibility Index R2, corresponds to the Reproducibil-ity Index R of Practice E1601. Likewise the RepeatabilityIndex R1of Practice E

34、173 corresponds to the RepeatabilityIndex r of Practice E1601.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 %, cadmium from0.001 % to 0.5 %, copper from 0.001

35、% to 1.3 %, iron from0.003 % to 0.1 %, lead from 0.002 % to 1.6 %, and magnesiumfrom 0.001 % to 0.1 %.19. Summary of Test Method19.1 An HCl solution of the sample is aspirated into theflame of an atomic absorption spectrometer. The absorption ofthe resonance line energy from the spectrum of each ele

36、ment ismeasured and compared with that of calibration solutions ofthe same element. The wavelengths of the spectral lines andother method parameters are tabulated in 22.1 for each ele-ment.20. Calibration Composition Range20.1 The calibration composition range for each elementmust be determined expe

37、rimentally, because the optimumrange will depend upon the individual instrument. If theoptimum calibration range and instrument parameters havebeen determined, proceed in accordance with Section 26;otherwise, determine the calibration range in accordance withSection 22.NOTE 5The composition range wi

38、ll depend on the instrument. Section24.1 lists the typical calibration composition ranges that most often will beacceptable, however this can be determined by using the criteria in Section22. The analyst may find that different calibration composition ranges arerequired and must adjust accordingly t

39、o suit their instrument.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 Spectrometer, equipped with a pre-mix burner, with facilities for using the oxidizer-fuel combi-nations

40、listed in Table 4. Use hollow-cathode lamps operated inaccordance with manufacturers recommendations as sourcesfor the spectral lines. The instrument may be consideredsuitable for this test method if a composition range can befound for which the minimum response, calibration variability,and referenc

41、e variability tabulated in Table 4 can be met.22.1.1 Prepare the dilute standard solution, reference, andcalibration solutions in accordance with Section 24. Refer toTable 5 for suggested initial concentrations.22.1.2 Prepare the instrument for use in accordance with in26.1. Measure the instrument r

42、esponse 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 difference be-tween the readings of the two highest of the five equally spacedcalibration solutio

43、ns. This difference must be equal to orgreater than the number of scale units specified in Table 4. Forpurposes of this test method, the scale unit is defined as one inthe least significant digit of the scale reading of the mostconcentrated calibration solution.TABLE 3 Statistical InformationTestSpe

44、cimenAluminumFound, %Repeatability(R1, E173)Reproducibility(R2, E173)G-3 0.3998 0.0190 0.0254H-2 4.04 0.052 0.074TABLE 4 Minimum Response, Calibration, and ReferenceVariabilityElementSpectralLine, nmOxidizer-FuelStandardSolutionMinimumResponse,UnitsCalibra-tion Vari-ability, %ReferenceVariabil-ity,

45、%Aluminum 309.2 N2OC2H2“A”“B”9253.51.02.00.5Cadmium 228.8 AirC2H2. 50 0.8 0.4Copper 324.7 AirC2H2“A”“B”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 0.8E536 15322.1.4 Curve LinearityCalculate the difference betweenthe

46、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 22.1.3 toabsorbance units. Divide the difference for the highest intervalby that for the lowest interval. This ratio must be

47、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 suitable. In this case, proceed inaccordance with 22.1.7; otherwise, proceed as follows:22.1.6 If the minimum response is not ac

48、hieved, 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 criterion, prepare another dilutestandard solution to provide a lower concentration range, andrepeat 22.1.1 22.1.4. If a concentrati

49、on range cannot be foundfor 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)where:Vc= calibration variability,c = average absorbance value for the highest cali-bration solution,C = individual absorbance readings on the highestcalibration solution,(c c)2= sum of the squares of the n differences be-tween th