1、Designation: E316 17Standard Test Method forDetermination of Iron in Manganese Ores by HydrogenSulfide Reduction-Dichromate Titrimetry1This standard is issued under the fixed designation E316; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、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 iron inmanganese ore in the range from2%to20%.NOTE
3、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 1g/100g.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 d
4、oes 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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This internati
5、onal standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Commi
6、ttee.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated M
7、aterialsE135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE882 Guide for Accountability and Quality Control in theChemical Analysis Laboratory3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology E135.4. Summary of T
8、est Method4.1 The sample is decomposed by treatment with HCl, HFand H2SO4.Any residue is treated for the recovery of insolubleiron. The iron is reduced with hydrogen sulfide, the insolublesulfides are removed by filtration, and the excess hydrogensulfide is expelled by boiling.After cooling, the red
9、uced iron istitrated with a standard potassium dichromate solution usingsodium diphenylamine sulfonate 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 u
10、se these 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 f
11、ollowed such as those describedin Guide E882.6. Interferences6.1 None of the elements normally found in manganese oreinterfere with this test method.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall re
12、agents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.3Other grades may be used,1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materia
13、ls and is the directresponsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-lurgical Materials.Current edition approved Dec. 15, 2017. Published January 2018. Originallyapproved in 1967. Last previous edition approved in 2011 as E316 11. DOI:10.1520/E0316-17.2For referenced AS
14、TM 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.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical
15、Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see the United States Pharmacopeia andNational Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West C
16、onshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade
17、 Organization Technical Barriers to Trade (TBT) Committee.1provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall mean reagent water c
18、onforming to Type I or II ofSpecification D1193. Type III or IV may be used if they effectno measurable change in the blank or sample.7.3 Ferrous Ammonium Sulfate Solution (approx. 0.10 N)Dissolve 40 g of ferrous ammonium sulfate(FeSO4(NH4)2SO46H2O) in H2SO4(1 + 19). Transfer to a 1-Lflask and dilut
19、e to volume with H2SO4(1 + 19). When thesample solution is ready for titration, standardize theFeSO4(NH4)2SO46H2O solution against the standard potas-sium dichromate solution (0.1000 N)(7.6) as described in 11.1.Calculate the millilitres of standard potassium dichromatesolution equivalent to 1 mL of
20、 the FeSO4(NH4)2SO46H2Osolution.7.4 Hydrogen Sulfide(H2S).7.5 Hydrogen Sulfide Wash Solution.7.5.1 Saturate H2SO4(1 + 99) with H2S. Prepare fresh asneeded.7.6 Potassium Dichromate, Standard Solution (0.1000 N)7.6.1 Dissolve 4.9035 g of Primary Standard Grade potas-sium dichromate (K2Cr2O7) in water,
21、 transfer to a 1-L volu-metric flask, dilute to volume, and mix.7.7 Sodium Diphenylamine Sulfonate Indicator Solution (2g/L).7.7.1 Dissolve 0.20 g of sodium diphenylamine sulfonate in100 mL of water. Store in a dark-colored bottle.7.8 Sodium Pyrosulfate (Na2S2O7).8. Hazards8.1 For precautions to be
22、observed in this method, refer toPractices E50.8.1.1 WarningCaution should be used for HF in 10.2.8.1.2 WarningCaution should be used for H2Sin10.5.9. Sampling and Sample Preparation9.1 The test unit shall be collected and prepared to maintainthe representative iron content in the lot.9.2 The labora
23、tory sample shall be pulverized to pass a150-um (No. 100) sieve.9.3 Weigh approximately (within 6 25 mg) an amount oftest sample specified as follows:Content of Iron, % Mass of Sample, g2to10 2.010 to 20 1.010. Procedure10.1 Transfer the test sample to a small, dry weighing bottleand place into a dr
24、ying oven.After drying at 120 C for 1 h, capthe bottle and cool 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 mass loss. Transfer the testsample to a 400-m
25、L beaker and reweigh the capped bottle tothe nearest 0.1 mg. The difference between the two masses isthe mass 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 actionsub
26、sides.Add 10 drops to 15 drops of HF and 15 mLof H2SO4,and heat to copious fumes of SO3(do not prolong fuming).Cool, rinse the sides of the beaker with a few millilitres ofwater, and again heat to fumes of SO3. Cool, add 100 mL ofwater, and heat to boiling.10.3 Filter off any residue through a mediu
27、m texture paperinto a 400-mL beaker and wash the paper and residue 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 drops to 4drops of H2SO4(1 + 1) and 5 mL of
28、 HF. Evaporate slowly toexpel the silica and the excess H2SO4.Add3gofNa2S2O7tothe crucible and fuse over a burner until a clear melt isobtained. Dissolve the cool melt in a few millilitres of waterand add this solution and the washings of the crucible andcover to the reserved filtrate.10.5 Dilute th
29、e solution with water to a volume of 250 mLand heat to boiling. Remove from the heat source and pass arapid stream of H2S through the solution for 15 min. Digest at60 C for 15 min and filter through a medium texture paperwith the aid of paper pulp into a 500-mL Erlenmeyer flask.Wash the precipitated
30、 sulfides thoroughly with the H2S washsolution. Add a few glass beads to the flask to preventbumping, heat the solution to boiling, and boil for 15 min to 20min to completely expel the H2S. (Check with lead acetate testpaper.) Remove from the heat source, cover the flask with asmall watch glass, and
31、 cool to 20 C in running water.10.6 To the cool solution add 5 mL of H3PO4and 5 drops ofthe sodium diphenylamine sulfonate indicator solution. Dilutewith water to approximately 300 mL and titrate with thestandard K2Cr2O7solution to a distinct purple end point.11. Blank Determination11.1 Determine th
32、e blank value of the reagents concurrentlywith the test determination, 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
33、 350 mL of cold H2SO4(1 + 19) andadd an accurately measured 1 mL of theFeSO4(NH4)2SO46H2O solution. Add 5 mL of sodium diphe-nylamine sulfonate indicator solution and titrate with theK2Cr2O7solution. Record this titration and subtract from thetitration of the blank solution to obtain the corrected b
34、lank.NOTE 2In the absence of iron, the sodium diphenylamine sulfonateindicator 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 millilitre
35、s of K2Cr2O7solution.E316 17212. Calculation12.1 Calculate the iron content as follows:Iron, % 5FA 2 B! 3 CDG3100 (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 millil
36、itre, andD = grams of sample used.12.2 Rounding of test results obtained using this test methodshall be performed in accordance with Practice E29, RoundingMethod, unless an alternative rounding method is specified bythe customer or applicable material specification.13. Precision and Bias13.1 Precisi
37、onTable 1 indicates the precision of this testmethod between laboratories using samples as the unknowns.13.2 BiasNo information on the bias of this test method isknown. Accepted values for the reference materials used in theinterlaboratory study were not available for evaluation. Usersof the method
38、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 dichromate titrimetry; iron content; manganese oreASTM International
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42、t 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
43、 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 1 Statistical InformationAverage IronContent,A%Relative StandardDeviation, %Number ofDeter-minationsNumber ofParticipatingLaboratories5.18 0.7 17 85.57 1.6 17 8AEach average iron content represents a different kind of manganese ore.E316 173
