1、Designation: E 465 00 (Reapproved 2005)Standard Test Methods forDetermination of Manganese (IV) in Manganese Ores byRedox Titration1This standard is issued under the fixed designation E 465; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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 These test methods cover the determination of manga-nese dioxide in amounts commonly found in man
3、ganese ore.The determination 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 (
4、Periodate (Sodium Oxalate) 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
5、 this standard 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:2D 1193 Specification for Reagent WaterE50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical An
6、alysis of Metals, Ores, and RelatedMaterialsE 135 Terminology Relating to Analytical 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, ref
7、er to Terminology E 135.4. 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
8、procedures skillfully 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 E 882.5. Interferences5.1 The elements or
9、dinarily present in manganese 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
10、of the American Chemical 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, referenc
11、esto water shall be understood to mean reagent water as definedby Type I of Specification D 1193.7. Hazards7.1 For precautions to be observed in these methods, refer toPractice E 50.8. Sampling and Sample Preparation8.1 The sample shall pass a No. 100 (150-m) sieve.1These test methods are under the
12、jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and are the directresponsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-lurgical Materials.Current edition approved Oct. 1, 2005. Published October 2005. Originallyapproved in 1
13、972. Last previous edition approved in 2000 as E 465 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.3Reag
14、ent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see “Reagent Chemicals and Standards,”by Joseph Rosin, D. Nostrand Co., Inc., New York, NY, and the “United States
15、Pharmacopeia.”1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.TEST METHOD AFERROUS AMMONIUMSULFATE METHOD9. Summary of Test Method9.1 The test sample is dissolved in an excess of ferrousammonium sulfate solution. The manganese dioxid
16、e reactswith an equivalent amount of ferrous iron. The excess ferrousiron is titrated with standard potassium dichromate solutionusing sodium diphenylamine sulfonate as an indicator.10. Reagents and Materials10.1 Ferrous Ammonium Sulfate Solution (45 g/L)Dissolve 45 g of ferrous ammonium sulfateFe(N
17、H4)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 Primary 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 In
18、dicator Solution (2g/L)10.3.1 Dissolve 0.20 g of sodium diphenylamine sulfonatein 100 mL of water. Store in a dark-colored bottle.11. Procedure11.1 Transfer approximately 0.4 g of test sample to a small,dry weighing bottle and place in a drying oven. Dry at 120Cfor 1 h, cap the bottle, and cool to r
19、oom temperature in adesiccator. Momentarily release the cap to equalize the pres-sure and weigh the capped bottle to the nearest 0.1 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 n
20、earest 0.1 mg. The differenceis the weight of the test sample.11.2 Add 50.0 mL of the ferrous ammonium sulfate solu-tion, plus an additional 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.1
21、1.3 Heat the flask moderately and shake intermittently untilthe ore is decomposed.11.4 Cool the contents of the flask while maintaining theflow of carbon dioxide.11.5 Unstopper the flask, add 2 mL of sodium dipheny-lamine sulfonate indicator solution, and 10 mL of H3PO4.Dilute to 150 mL with cold wa
22、ter (from which the air wasremoved by boiling) and titrate the excess ferrous ammoniumsulfate with standard K2Cr2O7solution to a permanent purpleend point.11.6 The correlation between the solutions of ferrous am-monium sulfate and potassium dichromate is established undertest conditions. For this pu
23、rpose, pour into a flask the sameamount of ferrous ammonium sulfate solution used to dissolvethe ore, and proceed as directed in 11.3.12. Calculation12.1 Calculate the percentage of manganese dioxide asfollows:Manganese dioxide, % 5 A 2 B! 3 C 3 4.3465/D (1)where:A = millilitres of standard K2Cr2O7s
24、olution used to estab-lish the correlation in 11.6,B = millilitres of standard K2Cr2O7solution required totitrate the excess of ferrous ammonium sulfate in thesample solution,C = the normality of standard K2Cr2O7solution, andD = grams of test sample used.13. Precision and Bias13.1 PrecisionTable 1 i
25、ndicates 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 acceptedreference mate
26、rials, 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 test sample is disso
27、lved 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 (0.025 M)15.1.1 Disso
28、lve 1.485 g of 1,10-phenanthroline monony-drate and 0.695 g of ferrousulfate (Fe SO47 H2O) in 50 mL ofwater. 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 the dark for twoweeks.
29、 Filter, without washing, through a Gooch crucible or afine porosity fritted-glass crucible. Avoid contact with rubberor other organic material. Store in a dark-colored glass-stoppered bottle.TABLE 1 Statistical InformationSample MethodAverageConcen-tration,%RelativeStandardDeviation,A%Number ofDete
30、rmin-ationsNumber ofParticipatingLaboratories1 A 40.87 0.54 35 72 A 70.23 0.47 29 61 B 40.90 0.46 29 82 B 70.32 0.38 29 8ARelative 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
31、the mean, andn = number of determinations.E 465 00 (2005)215.2.2 StandardizationDry a portion of the primary stan-dard sodium oxalate at 105C. Transfer 0.3000 g of the sodiumoxalate to a 600-mL beaker. Add 250 mL of H2SO4(5 + 95),previously boiled for 10 to 15 min and then cooled to 27 63C, and stir
32、 until the oxalate has dissolved. Add 39 to 40 mL(Note 1) 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 2). Heat to 55 to 60C and complete thetitration by adding KMnO4solution until a faint pink colorpersists for
33、 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, with KMnO4solution to a faint pink color.The blank correction is usually equivalent to 0.03 3 0.05 mL.NOTE 1A 0.3000
34、-g portion of sodium oxalate requires 44.77 mL ofKMnO4solution (0.1 N).NOTE 2If the KMnO4solution is too strong, the pink color will fadeat this point; begin again, adding a few millilitres less of the InO4solution.15.3 Sodium OxalateDry the reagent for2hat105Cprior to use.16. Procedure16.1 Transfer
35、 approximately 0.4 g of test sample to a small,dry weighing bottle and place in a drying oven. Dry at 120Cfor 1 h, cap the bottle, and cool to room temperature in adesiccator. Momentarily release the cap to equalize pressureand weigh the capped bottle to the nearest 0.1 mg. Repeat thedrying and weig
36、hing 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 weight 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 sm
37、all 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 decomposition is complete, rinse the contents ofthe flask into a 600-mL beaker and adjust the volume to about200 mL with hot water
38、. Add 2 to 3 drops of the 1,10phenanthroline indicator solution and titrate the hot solution(60 to 70C) with the standard KMnO4solution (Note 3). Atthe end point, the color will change from pink to green.NOTE 3The titration may be performed without using the indicator byobserving a pink end point du
39、e to excess potassium permanganate.16.5 The correlation between the sodium oxalate and thestandard permanganate solution is established under test con-ditions. For this 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.
40、 Calculation17.1 Calculate the percentage of manganese dioxide asfollows:Manganese dioxide, % 5 A 2 B! 3 C 3 4.3465/D (2)where:A = millilitres of standard KMnO4solution used to titrate0.8000 g of sodium oxalate,B = millilitres of standard KMnO4solution used to titratethe excess of sodium oxalate in
41、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 testmethod between laboratories.18.2 BiasNo information on the bias of this test method isknown. Accepted reference materials may ha
42、ve 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 bias of themethod from the difference between the accepted value for themanganese dioxide content of the reference material
43、and themean value from interlaboratory testing of the referencematerial.19. Keywords19.1 manganese dioxide content; manganese oresASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard a
44、re 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 and must be reviewed every five years andif not
45、 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 of theresponsible technical committee, which y
46、ou 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 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).E 465 00 (2005)3
