1、Designation: E507 09Standard Test Method forDetermination of Aluminum in Iron Ores by Flame AtomicAbsorption Spectrometry1This standard is issued under the fixed designation E507; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of aluminumin iron ores, concentrates, and agglomerates in the mass
3、fraction (%) range from 0.1 to 5.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o
4、f this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical
5、 Analysis of Metals, Ores, andRelated MaterialsE135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE276 Test Method for Particle Size or Screen Analysis atNo. 4 (4.75-mm) Sieve and Finer for Metal-Bearing Oresand Related MaterialsE663 Practice for Flame Atomic Abs
6、orption Analysis3E882 Guide for Accountability and Quality Control in theChemical Analysis Laboratory3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology E135.4. Summary of Test Method4.1 The sample is dissolved in HCl with the addition of asmall amount
7、 of HNO3. After evaporation and dehydration,any insoluble residue is filtered, treated for the recovery ofaluminum, and added to the main solution. The solution isaspirated into the flame of a nitrous oxide-acetylene burner.The absorbed energy at the resonance line of the spectrum ofaluminum is meas
8、ured by atomic absorption spectrometry andcompared with that of the calibration solutions.5. Significance and Use5.1 This test method is intended as a referee method forcompliance with compositional specifications for impuritycontent. It is assumed that all who use this procedure will betrained anal
9、ysts capable of performing common laboratorypractices skillfully and safely. It is expected that work will beperformed in a properly equipped laboratory and that properwaste disposal procedures will be followed. Follow appropriatequality control practices such as those described in GuideE882.6. Inte
10、rferences6.1 None of the elements normally found in iron oresinterfere with this test method.7. Apparatus7.1 Atomic Absorption Spectrometer, meeting the followingcriteria:7.1.1 Minimum SensitivityThe absorbance of the highestcalibration solution (see 8.4) must be at least 0.3.7.1.2 Curve-LinearityTh
11、e difference between the read-ings of the two highest calibration solutions must be more than1.4 times the difference between the readings for the zerosolution and the lowest calibration solution.7.1.3 Minimum StabilityThe coefficient of variation of anumber of measurements of the highest calibratio
12、n solutionand of the zero calibration solution must be less than 1.5 % and0.5 %, respectively.NOTE 1Use of digital readout devices or printers, or both, is advis-able.NOTE 2Instrument parameters will vary with each instrument. Thefollowing parameters were successfully used in several laboratories an
13、d1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and is the directresponsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-lurgical Materials.Current edition approved Oct. 1, 2009. Published April
14、2010. Originallyapproved in 1973. Last previous edition approved in 2008 as E507 08. DOI:10.1520/E0507-09.2For 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 standa
15、rds Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.they can be used as guidelines. Solutions wer
16、e aspirated into a nitrousoxide-acetylene flame of a premix burner.Hollow cathode lamp, mA 25Wavelength, nm 396.15Nitrous oxide flow rate, L/min 13.8Acetylene flow rate, L/min 6.68. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indica
17、ted, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its us
18、e without lessening the accuracy ofthe determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type I of Specification D1193.8.3 Aluminum, Standard Solution (1 mL = 0.5 mg Al)Dissolve 0.5000 g of high-purity aluminum in 2
19、5 mL of HCl,cool, transfer to a 1-L volumetric flask, dilute to volume, andmix.8.4 Aluminum Calibration SolutionsTransfer (5.0, 10.0,20.0, 40.0, and 50.0)-mL portions of the standard aluminumsolution to 200-mL volumetric flasks. Dilute to about 100 mL,add 6 mL of HCl and 60 mL of the background solu
20、tion, diluteto volume, and mix. These calibration solutions contain (12.5,25, 50, 100, and 125) g/mL Al, respectively.8.5 Iron, Background Solution (10 g/L)Dissolve 10 g ofhigh-purity iron in 50 mL of HCl and oxidize by the dropwiseaddition of HNO3. Evaporate to a syrupy consistency. Add 20mL of HCl
21、 and dilute to 200 mL with water. Add 20 g of NaCldissolved in 200 mL water and dilute to 1 L with water.8.6 Zero Calibration SolutionTransfer 60 mL of thebackground solution to a 200-mLvolumetric flask, add 6 mLofHCl, dilute to volume, and mix.9. Hazards9.1 For precautions to be observed in this me
22、thod, refer toPractice E50.10. Sample Preparation10.1 The analytical sample shall be pulverized to pass a150-m sieve (see Test Method E276).NOTE 3To facilitate decomposition, some ores, such as specularhematite, require grinding to pass a 75-m sieve.11. Procedure11.1 Transfer approximately 1.0 g of
23、the sample to a smallweighing bottle previously dried at about 150 C. Dry thebottle and contents for1hat105Cto110C.Capthebottleand cool to room temperature in a desiccator. Momentarilyrelease the cap to equalize the pressure and weigh the cappedbottle and sample to the nearest 0.1 mg. Repeat the dry
24、ing andweighing until there is no further weight loss. Transfer thesample to a 250-mL beaker and reweigh the capped bottle tothe nearest 0.1 mg. The difference between the two weights isthe weight of the sample taken for analysis.11.2 Carry a reagent blank through all steps of the procedurestarting
25、with 11.3.11.3 Decomposition of SampleMoisten the sample with afew millilitres of water, add 25 mL of HCl, cover and digestbelow the boiling point until no further attack is apparent. Add2mLofHNO3and digest for several minutes. Remove thecover and evaporate the solution to dryness. Heat the salts on
26、a hot plate at 105 C to 110 C for 15 min. Add 5 mL of HCl,cover the beaker, and warm for several min. Add 50 mL ofwater and warm until soluble salts are in solution. Filter on afine-textured paper, and collect the filtrate in a 250-mL beaker.Transfer the residue quantitatively to the filter paper. W
27、ashalternatively with hot dilute HCl (1 + 9) and hot water until theyellow color of ferric chloride is no longer apparent and thenwith hot water six to eight times. Transfer the paper and residueto a platinum crucible. Reserve the filtrate.11.4 Treatment of ResidueIgnite the paper and residue inthe
28、platinum crucible. Cool, moisten with several drops ofwater, and add three or four drops of H2SO4(1 + 1) and 10 mLof HF. Evaporate slowly to expel silica and then fume off theexcess of H2SO4. Ignite to about 700 C.Add1gofanhydrousNa2CO3to the residue, cover the crucible, and fuse over aburner or in
29、a muffle furnace until a clear melt is obtained.Dissolve the cool melt in the reserved filtrate from 11.3,remove and wash the crucible and cover. Transfer the solutionto a 200-mL volumetric flask, dilute to volume, and mix. If thesolution is cloudy at this stage, indicating the presence oftitania, f
30、ilter a portion of the solution through a dry paper intoa dry beaker. Use this solution for the atomic absorptionmeasurements, if the aluminum content is between 0.1 % and2.5 %. For aluminum contents greater than 2.5 %, transfer a40-mL aliquot to a 200-mL volumetric flask and add 50 mL ofbackground
31、solution and 4 mL of HCl. Dilute to volume andmix.11.5 Adjustment of Atomic Absorption SpectrometerInaccordance with Practice E663, set the initial instrumentparameters to the values in Note 2. Light the burner andaspirate water until the instrument comes to thermal equilib-rium. Optimize instrument
32、 response by adjusting the wave-length, fuel, air, burner, and nebulizer while aspirating thehighest calibration solution to obtain maximum absorption orabsorbance.Aspirate water until a steady signal is obtained andadjust the instrument readout system to obtain zero absorptionor absorbance.NOTE 4Th
33、e manufacturers instructions for igniting and extinguish-ing the nitrous oxide-acetylene burner should be strictly followed to avoidpossible explosion hazards. Tinted safety glasses should be worn by theoperator whenever the flame is burning.11.6 MeasurementsAspirate water until the initial readingi
34、s again obtained.Aspirate the calibration solutions in the orderof increasing absorption or absorbance starting with the zerocalibration solution. When a stable response is obtained foreach solution, record the readings.Aspirate the test solutions at4Reagent Chemicals, American Chemical Society Spec
35、ifications, AmericanChemical Society, Washington, DC, www.chemistry.org. For suggestions on thetesting of reagents not listed by the American Chemical Society, see the UnitedStates Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention,Inc. (USPC), Rockville, MD, http:/www.usp.org.E507 0
36、92the proper points in the calibration series. Aspirate waterbetween each calibration and test solution. Repeat all measure-ments at least two more times.12. Calculation12.1 If necessary, convert the average of the readings foreach calibration solution to absorbance. Obtain the net absor-bance of ea
37、ch calibration solution by subtracting the averageabsorbance of the zero calibration solution. In a similarmanner, obtain the net absorbance of the test solution bysubtracting the absorbance of the reagent blank solution.12.2 Prepare a calibration curve by plotting the net absor-bance values of the
38、calibration solutions against micrograms ofaluminum per milliliter.12.3 Convert the net absorbance values of the samplesolution to micrograms of aluminum per milliliter, by means ofthe calibration curve.12.4 Calculate the mass fraction (%) of aluminum as fol-lows:Aluminum, % 5 A 3 200!/B 3 10 000! (
39、1)where:A = aluminum, g/mL, andB = sample represented in the 200-mL volume of the finaltest solution, g.13. Precision and Bias13.1 PrecisionTable 1 indicates the precision of themethod within and between laboratories when applied to anumber of samples of iron ores.13.2 BiasNo information on the accu
40、racy of this testmethod is known. The accuracy of this test method may bejudged by comparison of accepted values for certified referencematerials, with the mean determined through interlaboratorytesting.14. Keywords14.1 aluminum; atomic absorption spectrometry; iron oresASTM International takes no p
41、osition 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 validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsib
42、ility.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 comments are invited either for revision of this standard or for additional standardsand should be addressed to
43、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 addre
44、ss shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 6
45、10-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 1 Precision of Method Within and Between LaboratoriesAverage Mass Fraction(%)Aof AlRelative
46、 Standard DeviationBWithin Laboratories, %Relative StandardDeviationBBetweenLaboratories, %Number of LaboratoriesNumber ofDeterminations0.178 4.49 7.87 30 880.261 4.21 18.77 31 910.426 2.58 5.40 11 310.667 1.35 2.40 7 190.884 1.81 6.11 24 721.46 2.53 2.47 29 852.14 2.01 5.14 31 91AEach mass fraction (%) of aluminum represents a different kind of iron ore.BRelative standard deviation (RSD), in this test method is calculated as follows:RSD 5 100/ X! =(d2!/n 2 1!where:X= average mass fraction (%),d = difference of the determination from the mean, andn = number of determinations.E507 093
