1、Designation: E841 12aStandard Test Method forDetermination of Copper in Iron Ores and Related Materialsby Flame Atomic Absorption Spectrometry1This standard is issued under the fixed designation E841; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、case of revision, the 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 copper iniron ores, concentrates, agglomera
3、tes, and related materials inthe concentration range from 0.003 % to 1 %.NOTE 1As used in this test method (except as related to the term“relative standard deviation”, “%” refers to a mass fraction (wt / wt %)(g/100g).1.2 The values stated in SI units are to be regarded asstandard. No other units of
4、 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 of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulator
5、y 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 Analysis of Metals, Ores, andRelated MaterialsE135 Terminology Relating to Analytical Chemistry forMetals, Ores, a
6、nd Related MaterialsE173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals3E276 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 Absorption Analysis3E87
7、7 Practice for Sampling and Sample Preparation of IronOres and Related Materials for Determination of ChemicalCompositionE882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analyti
8、cal MethodE1763 Guide for Interpretation and Use of Results fromInterlaboratory Testing of Chemical Analysis Methods3. 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 o
9、f asmall amount of HNO3and HF acids. After evaporation tofumes with HClO4, the solution is diluted with water andfiltered. A portion of the solution is examined by atomicabsorption spectrometry using standards containing approxi-mately the same amount of iron as the test sample.5. Significance and U
10、se5.1 In the making of iron and steel during the reduction ofiron ores, copper forms alloy with iron and steel hence thenecessity of determining the copper content for metallurgicalconsideration.1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores
11、, and Related Materials and is the directresponsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-lurgical Materials.Current edition approved June 1, 2012. Published July 2012. Originally approvedin 1981. Last previous edition approved in 2012 as E841 12. DOI: 10.1520/E0841-12A
12、.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 page onthe ASTM website.3Withdrawn. The last approved version of this historical sta
13、ndard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 This test method is intended to be used for compliancewith compositional specifications for copper content. It isassumed that all who use these pr
14、ocedures will be trainedanalysts 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
15、 as those described inGuide E882.6. Interferences6.1 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 8.6) must
16、 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 the zerosolution and the lowest calibration solution (see 8.6).7.1.3 Minimum StabilityThe relative standard deviationo
17、f a number of measurements of the highest calibrationsolution and of the zero calibration solution must be less than1.5 % and 0.5 % respectively, relative to the measurement ofthe highest calibration solution.NOTE 2A strip chart recorder or digital readout device, or both isadvisable to measure the
18、criteria in 7.1 and for all subsequent measure-ments.NOTE 3A background corrector equipped with a hydrogen or adeuterium hollow cathode lamp is advisable for the compositional rangefrom 0.003 % to 0.010 % Cu.NOTE 4Instrument parameters will vary with each instrument. Thefollowing parameters were suc
19、cessfully used in several laboratories andthey can be used as guidelines. Solutions were aspirated into anair acetylene flame of a premix burner.Hollow cathode lamp, mA 3Wavelength, nm 324.7Air flow-rate, L/min 10Acetylene flow-rate, L/min 2.58. Reagents and Materials8.1 Purity of ReagentsReagent gr
20、ade 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 specifications are available4. Other grades may be used,provided it is first ascertaine
21、d 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 water conformingto Type I or II of Specification D1193. Type III or IV may beuse
22、d if they effect no measurable change in the blank orsample.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 HNO3(1 + 1) and dilute to 1 L.8.4 Copper Standard Solution B (1 mL = 0.10 mg Cu)Transfer 100 mL of Standard Solution A to a 1-L vo
23、lumetricflask, 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 content of the sample, prepare a calibra-tion
24、solution using copper Standard Solution B or C. For therange of copper content from 0.01 % to 0.2 %, use copperStandard Solution B and for the range of copper content 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 ofcopper Standard Sol
25、ution B or C to 100-mL volumetric flasks.Add 20.0 mL of background solution, dilute to volume, andmix.8.7 Iron Background SolutionDissolve 15 g of high-purity iron metal in 150 mL HCl (1 + 2) and oxidize by thedropwise addition of HNO3. Add 250 mL of HClO4andevaporate to fumes. Allow to fume for 10
26、min, cool, and diluteto1L.8.8 Reference SolutionTransfer 20 mL of the backgroundsolution to a 100-mL volumetric flask, dilute to volume, andmix.9. Hazards9.1 For precautions to be observed in this method, refer toPractice E50.10. Sampling and Sample Preparation10.1 Collect and prepare the test unit
27、in accordance withPractice E877.10.2 The analytical sample shall be pulverized so that atleast 95 % passes a No. 100 (150-m) sieve in accordance withTest Methods E276.NOTE 5To facilitate decomposition, some ores, such as specularhematite, require grinding to pass a No. 200 (75-m) sieve.11. Procedure
28、11.1 Transfer approximately 0.5 g of the sample to a smallweighing bottle previously dried at about 150 C. Dry bottleand contents for 1 h at 105 C to 110 C. Cap the bottle andcool to room temperature in a desiccator. Momentarily releasethe cap to equalize the pressure and weigh the capped bottleand
29、sample to the nearest 0.1 mg. Repeat drying and weighinguntil there is no further loss of mass. Transfer the sample to a250-mLbeaker and reweigh the capped bottle to the nearest 0.1mg. The difference between the two masses is the mass of thesample taken for analysis.11.2 Carry a reagent blank throug
30、h all steps of the procedurestarting with 11.3.11.3 Decomposition of SampleMoisten the sample with afew millilitres of water, add 25 mL of HCl, cover, and digest4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of r
31、eagents notlisted by the American Chemical Society, see the United States Pharmacopeia andNational Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.E841 12a2below the boiling point until no further attack is apparent. Add5mLofHNO3and heat for 10 min. Remove the cover, add 3mL of
32、HF, and heat for 10 min. Rinse the wall of the beakerwith water, add 5 mL of HClO4, and evaporate slowly to densewhite fumes of HClO4. Fume for 2 min to 3 min and allow thesolution to cool. Add 50 mL of water and warm until thesoluble salts are in solution. Filter the solution through a finetexture
33、paper, wash the residue with warm water, receiving thefiltrate 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 HF and 2 drops of H2SO4. Add a few drops ofH2NO3. M
34、ix and evaporate to fumes of H2SO4. Cool, cau-tiously add 2 mL to 3 mL of water to dissolve the salts, andcombine with the reserved filtrate in the volumetric flask. Cool,dilute to volume, and mix. Use the test solution directly if theexpected content of copper in the sample is between 0.003 %and 0.
35、2 %. If the copper content exceeds 0.2 %, transfer 20 mLof the test solution to a 100-mL volumetric flask, add 16 mL ofiron background solution, dilute to volume, and mix.11.4 Reagent Blank SolutionTransfer the reagent blanksolution to a 100-mL volumetric flask, add 20 mL of ironbackground solution,
36、 dilute to volume, and mix.11.5 Adjustment of Atomic Absorption SpectrometerInaccordance with Practice E663, set the initial instrumentparameters to the values in Note 4 (7.1), light the burner, andaspirate water until the instrument comes to thermal equilib-rium. Optimize instrument response by adj
37、usting 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 6The manufacturers
38、instructions for igniting and extinguish-ing the 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 7Optimize the adjustment of the background corrector, ifnecessary (copper range
39、 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 isobtained for each solution, record t
40、he 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 average of the readings foreach cal
41、ibration 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 blank solution.12.2 Prepare a calibr
42、ation 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 Calculate the percentage of copper con
43、tent as follows:Copper, % 5AB 3 100(1)where:A = copper content 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 information on the bias of this test method isk
44、nown. 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 the accepted value for thecopper cont
45、ent and the mean value from interlaboratory testingof the reference material.NOTE 8This test method has been evaluated in accordance withPractice E173 (withdrawn 1997). The Reproducibility R2of Practice E173corresponds to the Reproducibility Index R of Practice E1601. TheRepeatability R1of Practice
46、E173 corresponds to the Repeatability Indexr of Practice E1601.14. Keywords14.1 agglomerates; concentrates; copper content; flameatomic absorption spectrometry; iron ores5Supporting data giving the results of cooperative testing are available fromASTM International Headquarters. Request RR:E16-1004.
47、TABLE 1 Precision DataIron ore XRepeatability(R1, E173)Reproducibility(R2, E173)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 copper content, %, andn = num
48、ber of laboratories.E841 12a3ASTM 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 inf
49、ringement 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 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
