1、Designation: E 507 03Standard Test Method forAluminum in Iron Ores by Atomic Absorption Spectrometry1This standard is issued under the fixed designation E 507; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 concentra-tion range fr
3、om 0.1 to 5 %.1.2 This standard does not purport to address all of thesafety problems, 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.2
4、. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2E 50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical Analysis of Metals3E 135 Terminology Relating to Analytical Chemistry forMetals, Ores and Related Materials3E 276 Test Method for Particle Size
5、 or Screen Analysis atNo. 4 (4.75-mm) Sieve and Finer for Metal-Bearing Oresand Related Materials3E 882 Guide for Accountability and Quality Control in theChemical Analysis Laboratory42.2 Other Documents:E 663-86 (1991) Practice for Flame Atomic AbsorptionAnalysis53. Terminology3.1 DefinitionsFor de
6、finitions of terms used in this testmethod, refer to Terminology E 135.4. Summary of Test Method4.1 The sample is dissolved in hydrochloric acid with theaddition of a small amount of nitric acid. After evaporation anddehydration, any insoluble residue is filtered, treated for therecovery of aluminum
7、, and added to the main solution. Thesolution is aspirated into the flame of a nitrous oxide-acetyleneburner. The absorbed energy at the resonance line of thespectrum of aluminum is measured by atomic absorptionspectroscopy and compared with that of the calibration solu-tions.5. Significance and Use
8、5.1 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 analysts capable of performing common laboratorypractices skillfully and safely. It is expected that work will beperf
9、ormed in a properly equipped laboratory and that properwaste disposal procedures will be followed. Follow appropriatequality control practices such as those described in GuideE 882.6. Interferences6.1 None of the elements normally found in iron oresinterfere with this test method.7. Apparatus7.1 Ato
10、mic Absorption Spectrophotometer, meeting the fol-lowing criteria:7.1.1 Minimum SensitivityThe absorbance of the highestcalibration solution (see 8.4) must be at least 0.3.7.1.2 Curve-LinearityThe difference between the read-ings of the two highest calibration solutions must be more than1.4 times th
11、e 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 calibration solutionand of the zero calibration solution must be less than 1.5 % and0.5 % respectively, relative to
12、 the measurement of the highestcalibration solution.NOTE 1Use of a strip chart recorder or digital readout device, or both,is advisable.NOTE 2Instrument parameters will vary with each instrument. Thefollowing parameters were successfully used in several laboratories andthey can be used as guidelines
13、. Solutions were aspirated into a nitrousoxide-acetylene flame of a premix burner.Hollow cathode lamp, mA 251This 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,
14、 Concentrates and Related Metal-lurgical Materials.Current edition approved June 10, 2003. Published July 2003. Originallyapproved in 1973. Last previous edition approved in 1988 as E 507 73 (1988).2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 03.05.4Annual Book of AS
15、TM Standards, Vol 03.06.5Available from Global Engineering Documents, 15 Inverness Way, EastEnglewood, CO 80112-57041Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Wavelength, l, A 3961.5Nitrous oxide flow rate, L/min 13.8Acetylene f
16、low rate, L/min 6.68. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specificati
17、ons are available6. Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent wate
18、r as definedby Type I of Specification D 1193.8.3 Aluminum, Standard Solution (1 mL = 0.5 mg Al)Dissolve 0.5000 g of high-purity aluminum in 25 mL ofhydrochloric acid (HCl, sp gr 1.19) and dilute to 1 L.8.4 Aluminum Calibration SolutionsTransfer 5.0, 10.0,20.0, 40.0, and 50.0-mL portions of the stan
19、dard aluminumsolution to 200-mL volumetric flasks. Dilute to about 100 mL,add 6 mL of HCl (sp gr 1.19) and 60 mL of the backgroundsolution, dilute to volume, and mix. These calibration solutionscontain 12.5, 25, 50, 100 and 125 g/mL A1, respectively.8.5 Iron, Background Solution (10 g/L)Dissolve 10
20、g ofhigh-purity iron in 50 mL of HCl (sp gr 1.19) and oxidize bythe dropwise addition of nitric acid (HNO3, sp gr 1.42).Evaporate to a syrupy consistency. Add 20 mL of HCl (sp gr1.19) and dilute to 200 mL with water. Add 20 g of sodiumchloride (NaCl) dissolved in 200 mL water and dilute to 1 Lwith w
21、ater.8.6 Zero Calibration SolutionTransfer 60 mL of thebackground solution to a 200-mL volumetric flask, add 6 mL ofHCl (sp gr 1.19), dilute to volume, and mix.9. Hazards9.1 For precautions to be observed in this method, refer toPractice E 50.10. Sample Preparation10.1 The analytical sample shall be
22、 pulverized to pass a No.100 (150-m) sieve (see Test Method E 276).NOTE 3To facilitate decomposition, some ores, such as specularhematite, require grinding to pass a No. 200 (75-m) sieve.11. Procedure11.1 Transfer approximately 1.0 g of the sample to a smallweighing bottle previously dried at about
23、150C. Dry the bottleand contents for1hat105to110C. Cap the bottle and coolto room temperature in a desiccator. Momentarily release thecap to equalize the pressure and weigh the capped bottle andsample to the nearest 0.1 mg. Repeat the drying and weighinguntil there is no further weight loss. Transfe
24、r the sample to a250-mL beaker and reweigh the capped bottle to the nearest 0.1mg. The difference between the two weights is the weight ofthe sample taken for analysis.11.2 Carry a reagent blank through all steps of the procedurestarting with 11.3.11.3 Decomposition of SampleMoisten the sample with
25、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 ona hot plate at 105 to 110C for 15 min. Add 5 mL of HCl, covert
26、he beaker, and warm for several min. Add 50 mL of water andwarm until soluble salts are in solution. Filter on a fine-texturedpaper, and collect the filtrate in a 250-mL beaker. Transfer theresidue quantitatively to the filter paper. Wash alternativelywith hot dilute HCl (1 + 9) and hot water until
27、the yellow colorof ferric chloride is no longer apparent and then with hot watersix to eight times. Transfer the paper and residue to a platinumcrucible. Reserve the filtrate.11.4 Treatment of ResidueIgnite the paper and residue inthe platinum crucible. Cool, moisten with several drops ofwater, add
28、3 or 4 drops of dilute sulfuric acid (H2SO4,1+1)and 10 mL of hydrofluoric acid (HF). Evaporate slowly toexpel silica and then fume off the excess of H2SO4. Ignite toabout 700C. Add1gofanhydrous sodium carbonate(Na2CO3) to the residue, cover the crucible, and fuse over aburner or in a muffle furnace
29、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, filter a portion o
30、f 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, add 50 mL ofbackground solution and 4 mL of H
31、Cl. Dilute to volume andmix.11.5 Adjustment of Atomic AbsorptionSpectrophotometerIn accordance with Practice E 663 (dis-continued 1979), set the initial instrument parameters to thevalues in Note 2. Light the burner and aspirate water until theinstrument comes to thermal equilibrium. Optimize instru
32、mentresponse by adjusting the wavelength, fuel, air, burner, andnebulizer while aspirating the highest calibration solution toobtain maximum absorption or absorbance. Aspirate wateruntil a steady signal is obtained and adjust the instrumentreadout system to obtain zero absorption or absorbance.NOTE
33、4The 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 readi
34、ngis again obtained. Aspirate the calibration solutions in the orderof increasing absorption or absorbance starting with the zerocalibration solution. When a stable response is obtained for6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For sug
35、gestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.E507032each solution, record
36、 the readings. Aspirate the test solutions atthe 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 a
37、bsorbance. Obtain the net absor-bance of each 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
38、plotting the net absor-bance values of the 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 percentage of aluminum as follows:A
39、luminum, % 5 A 3 200!/B 3 10 000! (1)where:A = aluminum, g/mL, andB = sample represented in the 200-mL volume of the finaltest solution, g.13. Precision and Bias713.1 PrecisionTable 1 indicates the precision of themethod within and between laboratories when applied to anumber of samples of iron ores
40、.13.2 BiasNo information on the accuracy of this testmethod is known. The accuracy of this test method may bejudged by comparison of accepted values for standard refer-ence materials, with the mean determined through interlabora-tory testing.14. Keywords14.1 aluminum; atomic absorption spectroscopy;
41、 iron oresASTM 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 validity of any such patent rights, and the riskof infringement of such r
42、ights, 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 comments are invited either for revision of this standard or for addition
43、al 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 AS
44、TM 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 reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the abo
45、veaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).7Supporting data giving the results of cooperative testing have been filed atASTM Headquarters.TABLE 1 Precision of Method Within and Between LaboratoriesAverage Concentra
46、tionAof A1, %Relative 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
47、91AEach concentration 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 concentration, %,d = difference of the determination from the mean, andn = number of determinations.E507033
