1、Designation: E738 11Standard Test Method forDetermination of Aluminum in Iron Ores and RelatedMaterials by EDTA Complexometric Titrimetry1This standard is issued under the fixed designation E738; 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method2covers the determination of aluminumin iron ores, concentrates, and agglomer
3、ates in the composi-tional range from 0.25 % to 5 % aluminum.NOTE 1As used in this test method (except as related to the termrelative standard deviation), “percent” or “%” refers to mass fraction(wt/wt) of the form g/100g.1.2 The values stated in SI units are to be regarded asstandard. No other unit
4、s 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 of this standard to establish appro-priate safety and health practices and determine the applica-bility of regul
5、atory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D1193 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, Ore
6、s, and Related MaterialsE877 Practice for Sampling and Sample Preparation of IronOres and Related Materials for Determination of ChemicalCompositionE882 Guide for Accountability and Quality Control in theChemical Analysis Laboratory3. Terminology3.1 DefinitionsFor definitions of terms used in this t
7、estmethod, refer to Terminology E135.4. Summary of Test Method4.1 The sample is fused in a zirconium crucible with amixed flux of sodium carbonate and sodium peroxide. Thefused mass is dissolved in dilute HCL. The R2O3(Note 2)hydroxides are precipitated with ammonia and redissolved inHCL. Iron, tita
8、nium, and so forth, are removed with cupferronand chloroform. The aqueous phase is treated with H2NO3andHClO4and evaporated to dryness. After dissolving in diluteHCL, the solution is filtered, and the filtrate is treated with anexcess of ethylenediaminetetraacetic acid (EDTA). The excessEDTA is titr
9、ated with a standard zinc solution using xylenolorange indicator. Ammonium fluoride is added to release theEDTA bound to aluminum. This EDTA is then titrated withstandard zinc solution, and the percent aluminum is calculated.NOTE 2R2O3hydroxides are rare earth sesquioxides such as La2O3,Y2O3,Ce2O3,G
10、d2O3, and Eu2O3.5. Significance and Use5.1 This test method for the analysis of iron ore concentratesand agglomerates is primarily intended as a referee method totest for compliance with compositional specifications. It isassumed that all who use this test method will be trainedanalysts capable of p
11、erforming 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 shall be followed, such as those described inGuide E882.6. Interfer
12、ences6.1 None of the elements normally found in iron oresinterfere with this test method.7. Apparatus7.1 Zirconium Crucible, 50-mL.1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and is the directresponsibility of Subco
13、mmittee E01.02 on Ores, Concentrates, and Related Metal-lurgical Materials.Current edition approved Sept. 1, 2011. Published September 2011. Originallyapproved in 1980. Last previous edition approved in 2005 as E738 00(2005). DOI:10.1520/E0738-11.2Bhargava, O. P., “Complexometric Determination of Al
14、uminum in Iron Ore,Sinter, Concentrates, and Agglomerates,” Talanta, Vol 26, 1979, pp. 146 to 148.3For 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
15、ment Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall
16、 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 sufficienthigh purity to permit its use without lessening the accur
17、acy 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 beused if they effect no measurable change in the blank orsample.8.3 Ammonium Chloride Solution (10
18、 g/L)Dissolve 10 gof ammonium chloride in water and dilute to 1 L. Add 2 drops(0.1 mL) of ammonium hydroxide per 100 mL of solution.8.4 Ammonium Fluoride SolutionDissolve 10 g of ammo-nium fluoride (NH4F) in 100 mL of water in a polyethylenebeaker. Prepare fresh each day.8.5 Cupferron Solution (60 g
19、/L)Dissolve6gofcupferronin 80 mL of cold water, dilute to 100 mL, and filter. Preparefresh as needed.8.6 Ethylenediaminetetraacetic Acid (EDTA) Solution(0.01 mol/L).8.7 Sodium Acetate Buffer SolutionDissolve 136 g ofsodium acetate trihydrate (CH3COONa3H2O) in about 600mL of water. Add 7 mL of glacia
20、l acetic acid and dilute to 1 L.Store in a polyethylene bottle.8.8 Sodium Carbonate.8.9 Sodium Hydroxide Solution A.8.9.1 Dissolve 100 g of sodium hydroxide (NaOH) in about100 mL of water. When dissolution is complete, cool, anddilute to 1 L. Store in a plastic bottle.8.10 Sodium Hydroxide Solution
21、BDilute 100 mL ofsodium hydroxide solution A to 1 L with water.8.11 Sodium Peroxide.8.12 Xylenol Orange IndicatorThoroughly grind 0.1 gxylenol orange with a little water to make a fine paste. Diluteto 100 mL with water, filter, and store in an amber-coloredglass stoppered bottle. The solution is sta
22、ble for 1 week.8.13 Zinc, Standard Solution (0.01 M)Weigh 0.6538 g ofhigh purity (99.99 % zinc) zinc metal into a 125-mL Erlen-meyer flask. Add 5 mL of water followed by 2 to 3 mL ofHNO3. Cover the flask and simmer. If the reaction subsidesleaving undissolved metal, add 2-mL increments of waterfollo
23、wed by simmering until complete solution is obtained.Add 50 mL of water and gently boil for 2 min. Cool. Bydropwise addition of sodium hydroxide solution B, adjust thepH to 4. Dilute to 1 L with water in a volumetric flask.9. Hazards9.1 For precautions to be observed in this method, refer toPractice
24、s E50.10. Sampling and Sample Preparation10.1 Sample the material in accordance with Practice E877.10.2 Pulverize the laboratory sample to pass a No. 100(150-m sieve).NOTE 3To facilitate decomposition, some ores, such as specularhematite, require grinding to pass a No. 200 (75-m) sieve.11. Procedure
25、11.1 Select and weigh a test sample in accordance with thefollowing:Aluminum, % Test Sample Mass, gTolerance in Test Samplemass, mg0.25 to 1 0.3 51to2 0.2 52to5 0.1 5Transfer the prepared sample to a small weighing bottlepreviously dried at about 105 C. Dry the bottle and contentsfor1hat105Cto110C.C
26、apthebottle and cool to roomtemperature in a desiccator. Momentarily release the cap toequalize the pressure and weigh the capped bottle and sampleto the nearest 0.1 mg. Repeat the drying and weighing untilthere is no further loss of mass. Transfer the test sample to adry, zirconium crucible contain
27、ing 0.5 g of sodium carbonateand reweigh the capped bottle to the nearest 0.1 mg. Thedifference between the two masses is the mass of the testsample taken for analysis. Add2gofsodium peroxide to thecrucible and mix with a dry, stainless steel spatula.11.2 Fuse over a burner, swirling the crucible un
28、til the meltis cherry red and clear. Remove from the heat and swirl untilthe melt solidifies on the wall of the crucible.11.3 Place the crucible in a 250-mL dry beaker and cool.Cover with a watchglass and add about 10 mL of water to thecrucible. After the reaction ceases, transfer the crucible con-t
29、ents into the beaker and wash the crucible with water. Add 20mL of HCl (1 + 1) by way of the crucible into the beaker. Rinsethe crucible with water and add rinsings to the beaker. Dilute toabout 70 mL with water and heat to boiling.11.4 Remove from heat and add NH4OH (1 + 1) dropwiseuntil the precip
30、itation of the hydroxides is complete (pH 6 topH 7). Boil for 1 min and immediately filter through amedium-textured paper. Wash five times with hot ammoniumchloride solution (10 g/L). Then wash five times with hotwater. Discard the filtrate. Place the unfolded filter paper on theinner wall of the or
31、iginal beaker and remove the precipitatefrom the paper with a fine jet of hot water. Then wash the filterpaper with 25 mL of hot HCl (1 + 1) and finally with a jet ofhot water. Discard the filter paper, cover the beaker with awatchglass, and bring the contents to a boil. Cool and adjust thevolume to
32、 50 mL using water. Cool to about 10 C.11.5 Transfer the test solution to a cold 250-mL separatoryfunnel. Rinse the beaker with 25 mL of cold water and add tothe separatory funnel. Add 25 mL of cold cupferron solutionand mix. Add 30 mL of chloroform and shake vigorously for 1min. Let the layers sepa
33、rate and draw off the organic phase and4Reagent Chemicals, American Chemical 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,
34、 U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.E738 112discard. Wash the aqueous layer with two successive additionsof 20 mL of chloroform, again discarding the organic phase.Wipe the stem of the separatory funnel with a fil
35、ter paper wick.11.5.1 Drain the aqueous phase into a 250-mL beaker,rinsing with 5 mL of HCl (1 + 5). Boil for a few minutes andremove from the heat. Add 5 mL of HNO3and 10 mL ofHClO4. Cover with a ribbed cover glass and evaporate nearlyto dryness. Remove from the heat and add 10 mL of HCl(1 + 1). He
36、at to dissolve the salts, add 50 mL of water, andbring to a boil. Filter through a medium-textured filter paperand wash several times with hot water.11.6 Cool and add 25.0 mL of EDTA solution. Using a pHmeter, adjust the pH to 2.5 by the dropwise addition of NaOHsolution A then to pH 4.0 by the drop
37、wise addition of NaOHsolution B. Dilute to 100 mL with water, cover the beaker, andboil gently for 10 min. Cool and add 15 mL of sodium acetatebuffer solution and 7 drops of xylenol orange indicatorsolution. Stir using a magnetic stirrer and titrate with zincstandard solution to a persistent (30 s)
38、pink end point.11.7 Add 10 mL of ammonium fluoride solution and boilgently for 10 min. Cool, add 2 drops to 3 drops of xylenolorange indicator solution, and titrate the liberated EDTA withzinc standard solution to a persistent (30 s) pink end point.12. Calculation12.1 Calculate the aluminum content
39、as follows:Aluminum dry basis!,%50.02698AB(1)where:A = millilitres of zinc standard solution used in 11.7, andB = grams of sample used.13. Precision and Bias513.1 PrecisionTable 1 indicates the precision of the testmethod between laboratories.BiasNo information on the bias of this test method isknow
40、n. Accepted reference materials may have not beenincluded in the materials used in the interlaboratory study.Users of this test method are encouraged to employ acceptedreference materials, if available, and to judge the bias of themethod from the difference between the accepted value for thealuminum
41、 content and the mean value from interlaboratorytesting of the reference material.14. Keywords14.1 agglomerates and related materials; aluminum content;concentrates; iron oresASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentio
42、nedin 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 responsibility.This standard is subject to revision at any time by the responsible technical committee an
43、d 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 o
44、f 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
45、 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), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permi
46、ssion rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).5Supporting data giving the results of cooperative testing are available fromASTM International Headquarters. Request RR:E16-1002.TABLE 1 Statistical InformationIron OreAverageAluminumContent, %RelativeStandardDeviation, %Number ofParticipatingLaboratoriesNumberof Determi-nationsMarcona 0.362 3.04 23 67Krivoj 0.661 2.72 23 67BCS 377 1.76 1.82 23 67Monette 2.34 1.79 23 66BCS 303 3.51 1.25 23 69Phillipine Iron Sand 1.44 1.25 23 68E738 113
