1、Designation: E465 11Standard Test Methods forDetermination of Manganese (IV) in Manganese Ores byRedox Titrimetry1This standard is issued under the fixed designation E465; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 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 These test methods cover the determination of manga-nese dioxide in amounts commonly found in manganese ore.The deter
3、mination measures the amount of manganese (IV)present in the sample. The result may be expressed as availableoxygen or as manganese dioxide. The following test methodsare included and may be used interchangeably:SectionsTest Method A (Ferrous Ammonium Sulfate) 9-13Test Method B (Periodate (Sodium Ox
4、alate) 14-181.2 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 to es
5、tablish appro-priate safety and health practices and determine the applica-bility of regulatory 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,
6、Ores, andRelated MaterialsE135 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 E1
7、35.4. Significance and Use4.1 This test method is intended to be used for compliancewith compositional specifications for manganese dioxide con-tent in manganese ores. It is assumed that all who use theseprocedures will be trained analysts capable of performingcommon laboratory procedures skillfully
8、 and safely. It isexpected that work will be performed in a properly equippedlaboratory and that proper waste disposal procedures will befollowed. Appropriate quality control practices shall be fol-lowed, such as those described in Guide E882.5. Interferences5.1 The elements ordinarily present in ma
9、nganese ores donot interfere in either test method.6. Reagents and Materials6.1 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 Chemic
10、al Society wheresuch 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.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be un
11、derstood 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.1These test methods are under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and
12、 are the directresponsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-lurgical Materials.Current edition approved Sept. 1, 2011. Published September 2011. Originallyapproved in 1972. Last previous edition approved in 2005 as E465 00 (2005).DOI: 10.1520/E0465-11.2For reference
13、d 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.3Reagent Chemical, American Chemical Society Specifications, AmericanChemic
14、al 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, U. K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc., (USPC), Rock
15、ville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Hazards7.1 For precautions to be observed in these methods, refer toPractice E50.8. Sampling and Sample Preparation8.1 The sample shall pass a No. 100 (150-m) sieve.TEST MET
16、HOD AFERROUS AMMONIUMSULFATE METHOD9. Summary of Test Method9.1 The test sample is dissolved in an excess of ferrousammonium sulfate solution. The manganese dioxide reactswith an equivalent amount of ferrous iron. The excess ferrousiron is titrated with standard potassium dichromate solutionusing so
17、dium diphenylamine sulfonate as an indicator.10. Reagents and Materials10.1 Ferrous Ammonium Sulfate Solution (45 g/L)Dissolve 45 g of ferrous ammonium sulfateFe(NH4)2(SO4)26H2O in 1 L of sulfuric acid (H2SO4, 1 + 7).10.2 Potassium Dichromate, Standard Solution (0.1 N)10.2.1 Dissolve 4.9035 g of Pri
18、mary Standard Grade potas-sium dichromate (K2Cr2O7) in water, transfer to a 1-L volu-metric flask, dilute to volume, and mix.10.3 Sodium Diphenylamine Sulfonate Indicator Solution,(2 g/L).10.3.1 Dissolve 0.20 g of sodium diphenylamine sulfonatein 100 mL of water. Store in a dark-colored bottle.11. P
19、rocedure11.1 Transfer approximately 0.4 g of test sample to a small,dry weighing bottle and place into a drying oven. Dry at 120 Cfor 1 h, cap the bottle, and cool to room temperature in adesiccator. Momentarily release the cap to equalize the pres-sure and weigh the capped bottle to the nearest 0.1
20、 mg. Repeatthe drying and weighing until there is no further weight loss.Transfer the test sample to a dry 300-mL Erlenmeyer flask andreweigh the capped bottle to the nearest 0.1 mg. The differenceis the mass of the test sample.11.2 Add 50.0 mL of the ferrous ammonium sulfate solu-tion, plus an addi
21、tional 10.0 mL for each 0.1 g of MnO2present, to the flask. Close the flask with a stopper equippedwith inlet and outlet tubes. Pass carbon dioxide through theflask.11.3 Heat the flask moderately and shake intermittently untilthe ore is decomposed.11.4 Cool the contents of the flask while maintainin
22、g theflow of carbon dioxide.11.5 Unstopper the flask, add 2 mL of sodium diphenylam-ine sulfonate indicator solution, and 10 mL of H3PO4. Dilute to150 mL with cold water (from which the air was removed byboiling) and titrate the excess ferrous ammonium sulfate withstandard K2Cr2O7solution to a perma
23、nent purple end point.11.6 The correlation between the solutions of ferrous am-monium sulfate and potassium dichromate is established undertest conditions. For this purpose, pour into a flask the sameamount of ferrous ammonium sulfate solution used to dissolvethe ore, and proceed as directed in 11.3
24、.12. Calculation12.1 Calculate the manganese dioxide content as follows:Manganese dioxide, % 5A 2 B! 3 C 3 4.3465D(1)where:A = millilitres of standard K2Cr2O7solution used to estab-lish the correlation in 11.6,B = millilitres of standard K2Cr2O7solution required totitrate the excess of ferrous ammon
25、ium sulfate in thesample solution,C = the normality of standard K2Cr2O7solution, andD = grams of test sample used.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.13. Precision and Bias13.
26、1 PrecisionTable 1 indicates the precision of the testmethod between laboratories.13.2 BiasNo information on the bias of this test method isknown. Accepted reference materials may have not beenincluded in the materials used in the interlaboratory study.Users of the method are encouraged to employ ac
27、ceptedreference materials, if available, and to judge the bias of themethod from the difference between the accepted value for themanganese dioxide content and the mean value from interlabo-ratory testing of the reference material.TEST METHOD BSODIUM OXALATE METHOD14. Summary of Test Method14.1 The
28、test sample is dissolved in sulfuric acid in thepresence of sodium oxalate. The manganese dioxide reactswith an equivalent amount of oxalate. The excess sodiumoxalate is titrated with a standard solution of potassiumpermanganate.15. Reagents and Materials15.1 1,10 Phenanthroline Indicator Solution (
29、0.025 M)15.1.1 Dissolve 1.485 g of 1,10-phenanthroline monohy-drate and 0.695 g of ferrous sulfate (Fe SO47 H2O) in 50 mLof water. Dilute to 100 mL.15.2 Potassium Permanganate, Standard Solution (0.1 N)15.2.1 PreparationDissolve 3.2 g of potassium perman-ganate (KMnO4) in 1 L of water. Let stand in
30、the dark for twoweeks. Filter, without washing, through a Gooch crucible or aTABLE 1 Statistical InformationSample MethodAverageManganeseDioxideContent,%RelativeStandardDeviation,%Number ofDetermin-ationsNumber ofParticipatingLaboratories1 A 40.87 0.54 35 72 A 70.23 0.47 29 61 B 40.90 0.46 29 82 B 7
31、0.32 0.38 29 8E465 112fine porosity fritted-glass crucible. Avoid contact with rubberor other organic material. Store in a dark-colored glass-stoppered bottle.15.2.2 StandardizationDry a portion of the primary stan-dard sodium oxalate at 105 C. Transfer 0.3000 g of the sodiumoxalate to a 600-mL beak
32、er. Add 250 mL of H2SO4(5 + 95),previously boiled for 10 to 15 min and then cooled to 27 C 63 C, and stir until the oxalate has dissolved.Add (39 to 40) mL(Note 2) of the KMnO4solution, at a rate of (25 to 35) mL/min,while stirring slowly. Let stand until the pink color disappears(about 45 s) (Note
33、3). Heat to 55 C to 60 C and complete thetitration by adding KMnO4solution until a faint pink colorpersists for 30 s. Add the last (0.5 to 1) mL dropwise, allowingeach drop to become decolorized before adding the next drop.To determine the blank: titrate 250 mL of H2SO4(5 + 95),treated as above, wit
34、h KMnO4solution to a faint pink color.The blank correction is usually equivalent to 0.03 mL to 0.05mL.NOTE 2A 0.3000-g portion of sodium oxalate requires 44.77 mL ofKMnO4solution (0.1 N)(10.2).NOTE 3If the KMnO4solution is too strong, the pink color will fadeat this point; begin again, adding a few
35、millilitres less of the KMnO4solution.15.3 Sodium OxalateDry the reagent for2hat105Cprior to use.16. Procedure16.1 Transfer approximately 0.4 g of test sample to a small,dry weighing bottle and place in a drying oven. Dry at 120 Cfor 1 h, cap the bottle, and cool to room temperature in adesiccator.
36、Momentarily release the cap to equalize pressureand weigh the capped bottle to the nearest 0.1 mg. Repeat thedrying and weighing until there is no further weight loss.Transfer the test sample to a dry 300-mL Erlenmeyer flask andreweigh the capped bottle to the nearest 0.1 mg. The differenceis the ma
37、ss of the sample.16.2 Add 100 mL of H2SO4(1 + 9) and 0.8000 g of sodiumoxalate to the flask.16.3 Cover the flask with a small cover glass and heat on asteam bath to decompose the ore. Swirl the flask occasionallyand continue heating until all dark colored particles havedisappeared.16.4 When decompos
38、ition is complete, rinse the contents ofthe flask into a 600-mL beaker and adjust the volume to about200 mL with hot water. Add 2 drops to 3 drops of the 1,10phenanthroline indicator solution and titrate the hot solution(60 C to 70 C) with the standard KMnO4solution (Note 4).At the end point, the co
39、lor will change from pink to green.NOTE 4The titration may be performed without using the indicator byobserving a pink end point due to excess potassium permanganate.16.5 The correlation between the sodium oxalate and thestandard permanganate solution is established under test con-ditions. For this
40、purpose, transfer 0.8000 g of sodium oxalateand 100 mL of H2SO4(1 + 9) to a 300-mL Erlenmeyer flask.Proceed as directed in 16.3.17. Calculation17.1 Calculate the manganese dioxide content as follows:Manganese dioxide, % 5A 2 B! 3 C 3 4.3465D(2)where:A = millilitres of standard KMnO4solution used to
41、titrate0.8000 g of sodium oxalate,B = millilitres of standard KMnO4solution used to titratethe excess of sodium oxalate in the sample solution,C = normality of the standard KMnO4solution, andD = grams of sample used.18. Precision and Bias18.1 PrecisionTable 1 indicates the precision of the testmetho
42、d between laboratories.18.2 BiasNo information on the bias of this test method isknown. 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 b
43、ias of themethod from the difference between the accepted value for themanganese dioxide content of the reference material and themean value from interlaboratory testing of the referencematerial.19. Keywords19.1 manganese dioxide content; manganese ores; redoxtitrimetryASTM International takes no po
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45、lity.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 A
46、STM 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 the addres
47、s 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 (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 ASTM website (www.astm.org/COPYRIGHT/).E465 113
