1、Designation: E1070 11Standard Test Method forDetermination of Phosphorus in Iron Ores by Phospho-Molybdenum-Blue Spectrophotometry1This standard is issued under the fixed designation E1070; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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 phospho-rus in iron ores, concentrates, and agglomerat
3、es in the concen-tration range from 0.005 to 1.0 % phosphorus.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 test method has been evaluated in accordance withPractice E1601 and Guide E1763. Unless otherwise noted i
4、nthe precision and bias section, the lower limit in the scope ofeach method specifies the lowest analyte content that may beanalyzed with acceptable error (defined as a nominal 5 % riskof obtaining a 50 % or larger relative difference in results onthe same test sample in two laboratories).1.4 This s
5、tandard 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 regulatory limitations prior to use.2. Referenced Documents2.
6、1 ASTM Standards:2D1193 Specification for Reagent WaterE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE60 Practice for Analysis of Metals, Ores, and RelatedMaterials by SpectrophotometryE135 Terminology Relating to Analyti
7、cal Chemistry forMetals, Ores, 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 LaboratoryE1601 Practice for Conducting an Interla
8、boratory Study toEvaluate the Performance of an Analytical 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 Metho
9、d4.1 The sample is fused in a zirconium crucible with sodiumperoxide. The melt is dissolved in water and hydrochloric acid.In a suitable aliquot, the molybdenum blue complex is formedby the addition of ammonium molybdate-hydrazine sulfatesolution. The absorbance of the phospho-molybdenum-bluecomplex
10、 is measured at 725 nm.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 users of this test method will be trained analystscapable
11、of performing common laboratory procedures skill-fully and safely. It is expected that work will be performed ina properly-equipped laboratory and that proper waste disposalprocedures will be followed. Appropriate quality control prac-tices shall be followed, such as those described in Guide E882.5.
12、2 The determination of this element is needed for inter-national trade and primary iron and steel making.6. Interferences6.1 Elements normally found in iron ores do not interfereexcepting arsenic giving positive interference (0.01 %As = 0.001 % P).7. Apparatus7.1 Zirconium Crucible, 50 mL capacity.1
13、This 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 Sept. 1, 2011. Published Septemb
14、er 2011. Originallyapproved in 1985. Last previous edition approved in 2005 as E1070 00 (2005).DOI: 10.1520/E1070-11.2For 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
15、 the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.2 SpectrophotometerVisible spectrophotometer capableof measuring absorbance at the 725 nm wavelength using a1-cm path length ce
16、ll in accordance with Practice E60.8. 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, wher
17、esuch specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficienthigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mea
18、n 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 Molybdate Solution (20 g/L)To 500 mL ofwater, add cautiously and slowly 300 mL of H2SO4and cool.Add 20 g of ammonium molybdate (NH4)6-Mo7
19、O244H2O. Stirto dissolve and dilute to 1 L with water.8.4 Fusion BlankDissolve4gofNa2O2in 40 mLof waterin a 250-mL beaker. Add 30 mL of HCl. Boil for 2 min. Cooland dilute to 100 mL with water in a volumetric flask. Preparefresh as needed.8.5 Hydrazine Sulfate (1.5 g/L)Dissolve 0.15 g of hydra-zine
20、sulfate NH2NH2H2SO4in water and dilute to 100 mLwith water. Prepare fresh as needed.8.6 Molybdate (5 g/L) Hydrazine Sulfate (0.15 g/L)SolutionAdd 50 mL of ammonium molybdate solution (20g/L) to 100 mL of water. Add 20 mL of hydrazine sulfatesolution (1.5 g/L) and dilute to 200 mL with water.NOTE 1Th
21、is solution should be prepared within 30 min of use in aquantity appropriate for the number of tests being made.8.7 Sodium Peroxide (Na2O2)Use caution when usingperoxide.8.8 Sodium Sulfite Solution (100 g/L)Dissolve 10 g ofsodium sulfite (Na2SO3) in water and dilute to 100 mL withwater.8.9 Standard
22、Phosphorus SolutionDry anhydrous diso-dium phosphate (Na2HPO4) at 105 C for 2 h and afterdesiccation, dissolve 0.2292 g of the reagent in 200 mL ofwater. Dilute to 1 L with water in a volumetric flask and mix.This solution, A, provides 1 mL = 50 g P. Transfer 10.00 mLof solutionAinto a 50-mLvolumetr
23、ic flask, dilute to mark withwater, and mix. This solution, B, provides the standardphosphorus solution for calibration 1 mL = 10 g P.9. Hazards9.1 For precautions to be observed in this method, refer toPractices E50.10. Sampling and Sample Preparation10.1 Collect and prepare gross samples in accord
24、ance withPractice E877.10.2 Pulverize the laboratory sample to pass a No. 100(150-m) sieve.NOTE 2To facilitate decomposition, some ores, such as specularhematite, require grinding to pass a No. 200 (75-m) sieve.11. Calibration and Standardization11.1 The recommended range of phosphorus content is fr
25、om0.005 mg to 0.10 mg phosphorus in 50 mL of color solutionusing cell depth of 1 cm.11.2 Into a series of five 150-mL beakers, transfer 10.0 mLof fusion blank solution (8.4) and then transfer (0, 0.50, 2.50)mL of standard B; 1.00 mL and 2.00 mL of standard Aphosphorus solution (8.9) corresponding to
26、 (0, 5, 25, 50, and100) g of phosphorus respectively. To each beaker add 15 mLof sodium sulfite solution (8.8). Mix. Bring to a boil. Add 20mL of molybdate-hydrazine sulfate solution (8.6). Bring to aboil. Simmer for 10 min in boiling water bath. Cool. Transferinto a 50-mL volumetric flask and dilut
27、e to the mark withwater. Mix. This solution is stable for at least 2 h.11.3 PhotometryAdjust the spectrophotometer to the ini-tial setting, using water as the reference solution. Whilemaintaining this setting, measure absorbance of the calibrationstandard and sample solutions at approximately 725 nm
28、 in a1-cm cell.11.4 Preparation of Calibration CurveSubtract the absor-bance of the 0-mL phosphorus standard solution from theabsorbance of each standard solution and plot the net absor-bance againstgofphosphorus in the color solution.12. Procedure12.1 Weigh approximately the amount of the prepareds
29、ample specified in the following table into a small weighingbottle previously dried at 150 C:3Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Stan
30、dards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.TABLE 1 Statistical InformationSampleAverage Phosphorus Content,%Standard DeviationRelativeStandardDeviation, %Number ofPar
31、ticipatingLaboratoriesNumber ofReplicatesJapan 830-1 (0.125)A0.1270 0.0035 2.75 8 24NBS 690 (0.011)A0.0085 0.0010 11.76 8 24NBS 692 (0.039)A0.0393 0.0022 5.61 8 24NBS 693 (0.056)A0.0554 0.0020 3.61 8 24ACertificate ValuePhosphorus content, %.E1070 112P Content, %Mass ofSample, gSampleAliquot, mLFusi
32、onBlank, mL0.005 to 0.15 0.300 10.0 None0.15 to 0.50 0.100 10.0 None0.50 to 1.0 0.100 5.0 5.0Dry the contents for1hat105Cto110C.Capthebottleand cool to room temperature in a desiccator. Momentarilyrelease the cap to equalize the pressure and weigh the cappedbottle and test sample to the nearest 0.1
33、mg. Repeat the dryingand weighing until there is no further loss of mass. Transfer thetest sample into a zirconium crucible and reweigh the cappedbottle to the nearest 0.1 mg. The difference between the twomasses is the weight of test sample taken for analysis. Add 2 gof sodium peroxide to the cruci
34、ble and mix with a dry, stainlesssteel spatula.NOTE 3As 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/100 g.12.2 Fuse over a burner, swirling the crucible until the meltis cherry red and clear. Remove
35、 from the heat and swirl untilthe melt solidifies on the wall of the crucible.12.3 Place the crucible in a 250-mL dry beaker and cool.Cover with a watch glass and add about 10 mL of water to thecrucible. After the reaction ceases, transfer the crucible con-tents into the beaker, and wash the crucibl
36、e with water. Add 15mL of HCl to the crucible and transfer to the beaker. Rinse thecrucible with water and add the rinsings to the beaker. Boil for2 min. Cool. Transfer the contents and rinsings into a 50-mLvolumetric flask. Dilute to volume with water and mix.12.4 Transfer appropriate aliquot of th
37、e test solution andfusion blank aliquot (in accordance with 11.2) into a 150-mLbeaker. Add 15 mL of sodium sulfite solution (100 g/L). Mix.Bring to a boil. Add 20 mL of molybdate (5 g/L) hydrazinesulfate solution (0.15 g/L). Bring to a boil. Simmer for 10 minin a boiling water bath. Cool. Transfer i
38、nto a 50-mL volumetricflask and dilute to the mark with water. Mix.12.5 Measure absorbance at approximately 725 nm in a1-cm cell in the same manner as the calibration standards.13. Calculation13.1 Subtract the absorbance of the 0-mL phosphorus stan-dard from the absorbance of the test sample solutio
39、ns. Deter-mine g phosphorus referring to the calibration curve.13.2 Calculate the phosphorus content as follows:Phosphorus, % 5S0.005AB 3 CD(1)where:A = g of phosphorus determined,B = sample aliquot in millilitres (12.1), andC = sample mass in grams (12.1).NOTE 4 As used in this test method, 9percen
40、tage9 or 9%9 refers to amass fraction of the form (wt / wt %) (g / 100 g).14. Precision and Bias414.1 PrecisionTable 1 indicates the precision of the testmethod between laboratories and comparison with the certifiedreference materials.14.2 BiasThe results obtained by the 8 laboratories on thecertifi
41、ed reference iron ores, of varying composition, agreeclosely within narrow limits with the assigned certified phos-phorus values, thus demonstrating absence of any measurablebias.15. Keywords15.1 agglomerates and related materials; concentrates; ironores; phosphorus contentASTM International takes n
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