1、Designation: E 841 04Standard Test Method forDetermination of Copper in Iron Ores and Related Materialsby Atomic Absorption Spectrometry1This standard is issued under the fixed designation E 841; the number immediately following the designation indicates the year oforiginal adoption or, in the case
2、of revision, the year of last revision. 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 copper iniron ores, concentrates, agglomerates,
3、 and related materials inthe concentration range from 0.003 to 1 %.1.2 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 ap
4、plica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterE50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical Analysis of Metals, Ores, and RelatedMaterialsE 135 Terminology Relating to Analytical Chem
5、istry forMetals, Ores, and Related MaterialsE 173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals3E 276 Test Method for Particle Size or Screen Analysis atNo. 4 (4.75-mm) Sieve and Finer for Metal-Bearing Oresand Related MaterialsE 663 Practice for Flame Ato
6、mic Absorption Analysis3E 877 Practice for Sampling and Sample Preparation of IronOres and Related MaterialsE 882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3
7、. Terminology3.1 DefinitionsFor definitions 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 and hydrofluoric acids.After evaporation to fumes with perchloric acid, the
8、solution isdiluted with water and filtered. A portion of the solution isexamined by atomic absorption spectroscopy using standardscontaining approximately the same amount of iron as the testsample.5. Significance and Use5.1 In the making of iron and steel during the reduction ofiron ores, copper for
9、ms alloy with iron and steel hence thenecessity of determining the copper concentration for metal-lurgical consideration.5.2 This test method is intended to be used for compliancewith compositional specifications for copper content. It isassumed that all who use these procedures will be trainedanaly
10、sts capable of performing common laboratory proceduresskillfully and safely. It is expected that work will be performedin a properly equipped laboratory and that proper wastedisposal procedures will be followed. Appropriate qualitycontrol practices must be followed, such as those described inGuide E
11、 882.1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and is the directresponsibility of Subcommittee E01.02 on Ores, Concentrates and Related Metal-lurgical Materials.Current edition approved May 1, 2004. Published June
12、 2004. Originallyapproved in 1981. Last previous edition approved in 1999 as E 841 99.2For 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 Document Summary
13、 page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Interferences6.1 None of the elements normally found in iron oresinterfere with this test method.7. Apparatus7.1 Atomic Absorption Spectrometer, m
14、eeting the followingcriteria:7.1.1 Minimum SensitivityThe absorbance of the highestcalibration solution (see 8.6) must be at least 0.3.7.1.2 CurveLinearityThe difference between the read-ings of the two highest calibration solutions must be more than1.4 times the difference between the readings for
15、the zerosolution and the lowest calibration solution (see 8.6).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 the measurement of the highes
16、tcalibration solution.NOTE 1A strip chart recorder or digital readout device, or both isadvisable to measure the criteria in 7.1 and for all subsequent measure-ments.NOTE 2A background corrector equipped with a hydrogen or adeuterium hollow cathode lamp is advisable for the concentration rangefrom 0
17、.003 to 0.010 % Cu.NOTE 3Instrument parameters will vary with each instrument. Thefollowing parameters were successfully used in several laboratories andthey can be used as guidelines. Solutions were aspirated into an air- acetylene flame of a premix burner.Hollow cathode lamp, mA 3Wavelength, nm 32
18、4.7Air flow-rate, L/min 10Acetylene flow-rate, L/min 2.58. 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 C
19、hemical Society wheresuch specifications are available4. 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 sha
20、ll be understood to mean reagent water as definedby Type I of Specification D 1193.8.3 Copper Standard Solution A (1 mL = 1.0 mg Cu)Dissolve 1.000 g of copper metal (minimum 99.5 %) in 30 mLof nitric acid (1 + 1) and dilute to 1 L.8.4 Copper Standard Solution B (1 mL = 0.10 mg Cu)Transfer 100 mL of
21、Standard Solution A to a 1-L volumetricflask, dilute to volume, and mix.8.5 Copper Standard Solution C (1 mL = 0.01 mg Cu)Transfer 100 mL of Standard Solution B to a 1-L volumetricflask, dilute to volume, and mix.8.6 Copper Standard Calibration SolutionDepending onthe expected copper concentration i
22、n the sample, preparecalibration solution using copper Standard Solution B or C. Forthe concentration range from 0.01 to 0.2 % Cu, use copperStandard Solution B and for the concentration range from0.003 to 0.02 %, use copper Standard Solution C.8.6.1 Transfer 1.0, 3.0, 5.0, 7.0, and 10.0-mL portions
23、 ofcopper Standard Solution B or C to 100-mL volumetric flasks.Add 20.0 mL of background solution, dilute to volume, andmix.8.7 Hydrochloric Acid (HCl) (1 + 1)Mix 1 volume ofhydrochloric acid (HCl) with 1 volume of water.8.8 Iron Background SolutionDissolve 15 g of high-purity iron metal in 150 mL H
24、Cl (1 + 2) and oxidize by thedropwise addition of HNO3. Add 250 mL of perchloric acid(HClO4) and evaporate to fumes. Allow to fume for 10 min,cool, and dilute to 1 L.8.9 Nitric Acid (HNO3) (1+1)Mix 1 volume of nitricacid (HNO3) with 1 volume of water.8.10 Reference SolutionTransfer 20 mL of the back
25、-ground solution to a 100-mL volumetric flask, dilute tovolume, and mix.9. Hazards9.1 For precautions to be observed in this method, refer toPractice E 50.10. Sampling and Sample Preparation10.1 Collect and prepare the test unit in accordance withPractice E 877.10.2 The analytical sample shall be pu
26、lverized so that atleast 95% passes a No. 100 (150-m) sieve in accordance withTest Methods E 276.NOTE 4To facilitate decomposition, some ores, such as specularhematite, require grinding to pass a No. 200 (75-m) sieve.11. Procedure11.1 Transfer approximately 0.5 g of the sample to a smallweighing bot
27、tle previously dried at about 150C. Dry 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 drying and weighing untilthere is no furthe
28、r weight loss. Transfer the sample to a 250-mLbeaker and reweigh the capped bottle to the nearest 0.1 mg.The difference between the two weights is the weight of thesample taken for analysis.11.2 Carry a reagent blank through all steps of the procedurestarting with 11.3.11.3 Decomposition of SampleMo
29、isten the sample with afew millilitres of water, add 25 mL of HCl, cover, and digestbelow the boiling point until no further attack is apparent. Add5mLofHNO3and heat for 10 min. Remove cover, add 3 mLof hydrofluoric acid, and heat for 10 min. Rinse wall of thebeaker with water, add 5 mL of HClO4, an
30、d evaporate slowlyto dense white fumes of HClO4. Fume for 2 to 3 min and allowthe solution to cool. Add 50 mL of water and warm until thesoluble salts are in solution. Filter the solution through a finetexture paper, wash the residue with warm water, receiving the4Reagent Chemical, American Chemical
31、 Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole Dorset, U. K., and the United States Pharmacopeia andNational Formulary, U.S. Pharma
32、ceutical Convention, Inc., (USPC), Rockville,MD.E841042filtrate and washings in a 100-mL volumetric flask. Ignite thefilter paper containing the insoluble residue in a platinumcrucible, moisten the residue with a few drops of water, addabout 3 mL of hydrofluoric acid and 2 drops of sulfuric acid.Add
33、 a few drops of nitric acid. Mix and evaporate to fumes ofsulfuric acid. Cool, cautiously add 2 to 3 mL of water todissolve the salts, and combine with the reserved filtrate in thevolumetric flask. Cool, dilute to volume, and mix. Use the testsolution directly if the expected content of copper in th
34、e sampleis between 0.003 and 0.2 %. If the copper concentrationexceeds 0.2 %, transfer 20 mL of the test solution to a 100-mLvolumetric flask, add 16 mLof iron background solution, dilutethe volume, and mix.11.4 Reagent Blank SolutionTransfer the reagent blanksolution to a 100-mL volumetric flask, a
35、dd 20 mL of ironbackground solution, dilute to volume, and mix.11.5 Adjustment of Atomic Absorption SpectrometerInaccordance with Practice E 663, set the initial instrumentparameters to the values in Note 3, 7.1, light the burner, andaspirate water until the instrument comes to thermal equilib-rium.
36、 Optimize instrument 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
37、 absorbance.NOTE 5The manufacturers instructions for igniting and extinguishingthe air acetylene burner should be strictly followed to avoid possibleexplosion hazards. Tinted safety glasses should be worn by the operatorwhenever the flame is burning.NOTE 6Optimize the adjustment of the background co
38、rrector, ifnecessary (copper range from 0.003 to 0.010 %).11.6 MeasurementsAspirate water until the initial readingis again obtained. Aspirate the calibration and test solutions inthe order of increasing absorption, starting with the reagentblank and reference solution. When a stable response isobta
39、ined for each solution, record the readings. Aspirate andrecord the readings of the test solutions at the proper points inthe calibration series. Aspirate water between each calibrationand test solution. Repeat all measurements at least two moretimes.12. Calculation12.1 If necessary, convert the ave
40、rage of the readings foreach calibration solution to absorbance. Obtain the net absor-bance of each calibration solution by subtracting the averageabsorbance of the reference solution. In a similar manner,obtain the net absorbance of the test solution by subtracting theabsorbance of the reagent blan
41、k solution.12.2 Prepare a calibration curve by plotting the net absor-bance values of the calibration solutions against micrograms ofcopper per milliliter.12.3 Convert the net absorbance value of the sample solu-tion to micrograms of copper per milliliter by means of thecalibration curve.12.4 Calcul
42、ate the percentage of copper as follows:Copper, % 5 A 3 100!/B 3 10 000! (1)where:A = concentration of the test solution, g/mL andB = weight of sample used, g.13. Precision and Bias513.1 PrecisionTable 1 indicates the precision of the testmethod within and between laboratories.13.2 BiasNo informatio
43、n on the bias of this test method isknown. Accepted reference materials may have not beenincluded in the materials used in the interlaboratory study.Users of the method are encouraged to employ acceptedreference materials, if available, and to judge the bias of themethod from the difference between
44、the accepted value for thecopper content and the mean value from interlaboratory testingof the reference material.NOTE 7This test method has been evaluated in accordance withPractice E 173 (withdrawn 1997). The Reproducibility R2of PracticeE 173 corresponds to the Reproducibility Index R of Practice
45、 E 1601. TheRepeatability R1of Practice E 173 corresponds to the Repeatability Indexr of Practice E 1601.14. Keywords14.1 agglomerates; concentrates; copper content; iron ores5Supporting data giving the results of cooperative testing are available fromASTM International Headquarters. Request RR: E16
46、-1004.TABLE 1 Precision DataIron ore XRepeatability(R1, E 173)Reproducibility(R2, E 173)nMalmbergets concentrate 0.001 0.0008 0.0014 35Kiruna 0.011 0.0020 0.0022 39Purpurerz 0.072 0.0036 0.0109 39Russ Abbrande 0.380 0.0165 0.0358 40Forsbo 0.787 0.0322 0.0521 40where:X = average concentration, %, and
47、n = number of laboratories.E841043ASTM 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 risko
48、f 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 comments are invited either for revision of this
49、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 reprints (single or multipl
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