1、Designation: E 316 00 (Reapproved 2005)Standard Test Method forDetermination of Iron in Manganese Ores by HydrogenSulfide Reduction-Dichromate Titration1This standard is issued under the fixed designation E 316; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case 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 iron inmanganese ore in the ran
3、ge from 2 to 20 %.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 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
4、 to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical Analysis of MetalsE 135 Terminology Relating to Analyt
5、ical Chemistry forMetals, Ores, and Related MaterialsE 882 Guide for Accountability and Quality Control in theChemical Analysis Laboratory3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology E 135.4. Summary of Test Method4.1 The sample is decomposed by
6、 treatment with hydro-chloric, hydrofluoric, and sulfuric acids. Any residue is treatedfor the recovery of insoluble iron. The iron is reduced withhydrogen sulfide, the insoluble sulfides are removed by filtra-tion, and the excess hydrogen sulfide is expelled by boiling.After cooling, the reduced ir
7、on is titrated with a standardpotassium dichromate solution using sodium diphenylaminesulfonate as the indicator.5. Significance and Use5.1 This test method is intended to be used for compliancewith compositional specifications for iron content in manga-nese ores. It is assumed that all who use thes
8、e procedures willbe trained analysts capable of performing common laboratoryprocedures skillfully and safely. It is expected that work will beperformed in a properly equipped laboratory and that properwaste disposal procedures will be followed. Appropriate qual-ity control practices must be followed
9、 such as those describedin Guide E 882.6. Interferences6.1 None of the elements normally found in manganese oreinterfere with this test method.7. Reagents and Materials7.1 Purity and Concentration of ReagentsThe purity andconcentration of the common chemical reagents used shallconform to Practices E
10、50. Special apparatus and reagentsrequired are located in separate sections preceding the proce-dure.7.2 Ferrous Ammonium Sulfate Solution (approx. 0.10N)Dissolve 40 g of ferrous ammonium sulfate(FeSO4(NH4)2SO46H2O) in sulfuric acid (1+19). Transfer to a1-L flask and dilute to volume with the same a
11、cid. When thesample solution is ready for titration, standardize theFeSO4(NH4)2SO46H2O solution against the standard potas-sium dichromate solution (0.1000 N) as described in 11.1.Calculate the millilitres of standard potassium dichromatesolution equivalent to 1 mL of the FeSO4(NH4)2SO46H2Osolution.
12、7.3 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).7.4 Hydrofluoric Acid (48 %)Concentrated hydrofluoricacid (HF).7.5 Hydrogen Sulfide (H2S).7.6 Hydrogen Sulfide Wash Solution.7.6.1 Saturate H2SO4(1+99) with hydrogen sulfide (H2S).Prepare fresh as needed.1This test method is und
13、er 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 Oct. 1, 2005. Published October 2005. Originallyapprove
14、d in 1967. Last previous edition approved in 2000 as E 316 00.2For 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
15、.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.7 Nitric Acid (sp gr 1.42)Concentrated nitric acid(HNO3).7.8 Phosphoric Acid (85 %)Concentrated phosphoric acid(H3PO4).7.9 Potassium Dichromate, Standard Solution (0.1000 N)7.9.1 Dis
16、solve 4.9035 g of Primary Standard Grade potas-sium dichromate (K2Cr2O4) in water, transfer to a 1-L volu-metric flask, dilute to volume, and mix.7.10 Sodium Diphenylamine Sulfonate Indicator Solution (2g/L).7.10.1 Dissolve 0.20 g of sodium diphenylamine sulfonatein 100 mL of water. Store in a dark-
17、colored bottle.7.11 Sodium Pyrosulfate (Na2S2O7).7.12 Sulfuric Acid (sp gr 1.84)Concentrated sulfuric acid(H2SO4).7.13 Sulfuric Acid (1+1)Mix 1 volume of concentratedH2SO4(sp gr 1.84) with 1 volume of water.7.14 Sulfuric Acid (1+19)Mix 1 volume of concentratedH2SO4(sp gr 1.84) with 19 volumes of wat
18、er.8. Hazards8.1 For precautions to be observed in this method, refer toPractices E 50.9. Sampling and Sample Preparation9.1 The test unit shall be collected and prepared to maintainthe representative iron content in the lot.9.2 The laboratory sample shall be pulverized to pass a No.100 (150-m) siev
19、e.9.3 Weigh approximately (within 625 mg) an amount oftest sample specified as follows:Content of Iron, % Weight of Sample, g2to10 2.010 to 20 1.010. Procedure10.1 Transfer the test sample to a small, dry weighing bottleand place in a drying oven. After drying at 120C for 1 h, capthe bottle and cool
20、 to room temperature in a desiccator.Momentarily release the cap to equalize pressure and weigh thecapped bottle to the nearest 0.1 mg. Repeat the drying andweighing until there is no further weight loss. Transfer the testsample to a 400-mL beaker and reweigh the capped bottle tothe nearest 0.1 mg.
21、The difference between the two weights isthe weight of the sample.10.2 Moisten the sample with a few millilitres of water, add15 mL of HCl, cover and heat gently until no further attack isapparent. Add 5 mL of HNO3and warm until the actionsubsides. Add 10 to 15 drops of HF and 15 mL of H2SO4, andhea
22、t to copious fumes of SO3(do not prolong fuming). Cool,rinse the sides of the beaker with a few millilitres of water, andagain heat to fumes of SO3. Cool, add 100 mL of water, andheat to boiling.10.3 Filter off any residue through a medium texture paperinto a 400-mL beaker and wash the paper and res
23、idue with hotwater until the iron color is removed from the paper. Reservethe filtrate.10.4 Ignite the paper and residue in a platinum crucible,cool, moisten with a few drops of water and add 3 to 4 dropsof H2SO4(1+1) and 5 mLof HF. Evaporate slowly to expel thesilica and the excess H2SO4.Add3gofNa2
24、S2O7to thecrucible and fuse over a burner until a clear melt is obtained.Dissolve the cool melt in a few millilitres of water and add thissolution and the washings of the crucible and cover to thereserved filtrate.10.5 Dilute the solution with water to a volume of 250 mLand heat to boiling. Remove f
25、rom the heat source and pass arapid stream of H2S through the solution for 15 min. Digest at60C for 15 min and filter through a medium texture paper withthe aid of paper pulp into a 500-mL Erlenmeyer flask. Wash theprecipitated sulfides thoroughly with the hydrogen sulfide washsolution. Add a few gl
26、ass beads to the flask to preventbumping, heat the solution to boiling, and boil for 15 to 20 minto completely expel the H2S. (Check with lead acetate testpaper.) Remove from the heat source, cover the flask with asmall watch glass, and cool to 20C in running water.10.6 To the cool solution add 5 mL
27、 of H3PO4and 5 drops ofthe sodium diphenylamine sulfonic indicator solution. Dilutewith water to approximately 300 mL and titrate with thestandard K2Cr2O7solution to a distinct purple end point.11. Blank Determination11.1 Determine the blank value of the reagents concurrentlywith the test determinat
28、ion, using the same amount of allreagents and following all the steps of the procedure. Imme-diately before titrating with the K2Cr2O7solution add 1.0 mL,accurately measured, of the FeSO4(NH4)2SO46H2O solution.In another beaker place 350 mL of cold H2SO4(1+19) and addan accurately measured 1 mL of t
29、he FeSO4(NH4)2SO46H2Osolution. Add 5 mL of sodium diphenylamine sulfonate indi-cator solution and titrate with the K2Cr2O7solution. Recordthis titration and subtract from the titration of the blanksolution to obtain the corrected blank.NOTE 1In the absence of iron, the sodium diphenylamine sulfonate
30、indicator does not react with the K2Cr2O7solution. The addition of theFeSO4(NH4)2SO46H2O is, therefore, necessary to promote indicatorresponse in the blank solution. A correction must be made in terms of itsequivalent in millilitres of K2Cr2O7solution.12. Calculation12.1 Calculate the percentage of
31、iron as follows:Iron, % 5 A 2 B! 3 C/D 3 100 (1)where:A = millilitres of K2Cr2O7solution required for titration ofsample,B = millilitres of K2Cr2O7solution required for titration ofblank,C = iron value of K2Cr2O7in grams per millilitre, andD = grams of sample used.13. Precision and Bias13.1 Precisio
32、nTable 1 indicates the precision of this testmethod between laboratories using standard samples as theunknowns.13.2 BiasNo information on the bias of this test method isknown. Accepted values for the reference materials used in theE 316 00 (2005)2interlaboratory study are not available for evaluatio
33、n. Users ofthe method are encouraged to employ accepted referencematerials, if available, and to judge the bias of the method fromthe difference between the accepted value for the iron contentand the mean value of the reference material.14. Keywords14.1 iron content; manganese oreASTM International
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36、ressed 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
37、 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 aboveaddress or at 610-832-9585
38、(phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 Statistical InformationAverageConcentration,A%Relative StandardDeviation,B%Number ofDeter-minationsNumber ofParticipatingLaboratories5.18 60.7 17 85.57 61.6 17 8AEach concentration represents a different kind of manganese 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.E 316 00 (2005)3
