1、Designation: E316 11E316 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 c
2、ase of 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 in manganese ore in the range from 2 %
3、to 20 %.NOTE 1As used in this test method (except as related to the term relative standard deviation), “percent” or “%” refers to mass fraction (wt/wt) ofthe form g/100g.1g/100g.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this stand
4、ard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitatio
5、ns prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technica
6、l Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE29 Practice for Using Significant Digits in Test Data to Determine Conformance with SpecificationsE50 Practices forApparatus, Reagents, and Safety Considerations for ChemicalAnalysis
7、of Metals, Ores, and Related MaterialsE135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related MaterialsE882 Guide for Accountability and Quality Control in the Chemical Analysis Laboratory3. Terminology3.1 DefinitionsFor definitions of terms used in this test method, refer to
8、 Terminology E135.4. Summary of Test Method4.1 The sample is decomposed by treatment with hydrochloric, hydrofluoric,HCl, HF and sulfuricH2SO4 acids. . Any residueis treated for the recovery of insoluble iron. The iron is reduced with hydrogen sulfide, the insoluble sulfides are removed byfiltration
9、, and the excess hydrogen sulfide is expelled by boiling. After cooling, the reduced iron is titrated with a standardpotassium dichromate solution using sodium diphenylamine sulfonate as the indicator.5. Significance and Use5.1 This test method is intended to be used for compliance with compositiona
10、l specifications for iron content in manganese ores.It is assumed that all who use these procedures will be trained analysts capable of performing common laboratory proceduresskillfully and safely. It is expected that work will be performed in a properly equipped laboratory and that proper waste dis
11、posalprocedures will be followed. Appropriate quality control practices must be followed such as those described in Guide E882.1 This test method is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcomm
12、ittee E01.02 on Ores, Concentrates, and Related Metallurgical Materials.Current edition approved Sept. 1, 2011Dec. 15, 2017. Published September 2011January 2018. Originally approved in 1967. Last previous edition approved in 20052011as E316 00 (2005). 11. DOI: 10.1520/E0316-11.10.1520/E0316-17.2 Fo
13、r referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to pro
14、vide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the
15、 standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Interferences6.1 None of the elements normally found in manganese ore interfere with this test method.7. Reage
16、nts and Materials7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where suchspecifications are availableavailabl
17、e.3. Other grades may be used, provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, references to water shall be understood to mean reagent water conforming
18、 toType I or II of Specification D1193. Type III or IV may be used if they effect no 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 sulfuricH2SO4 acid (1 + 19). Transfer to a 1-L flask an
19、d dilute to volume with sulfuricH2SO4 acid(1 + 19). When the sample solution is ready for titration, standardize the FeSO4(NH4)2SO46H2O solution against the standardpotassium dichromate solution (0.1000 N) (7.77.6) as described in 11.1. Calculate the millilitres of standard potassium dichromatesolut
20、ion equivalent to 1 mL of the FeSO4(NH4)2SO46H2O solution.7.4 Hydrogen Sulfide(H2S).7.5 Hydrogen Sulfide Wash Solution.7.5.1 Saturate H2SO4 (1 + 99) with hydrogen sulfide (HH2S).S. Prepare fresh as needed.7.6 Phosphoric Acid (85 %)Concentrated phosphoric acid (H3PO4 ).7.6 Potassium Dichromate, Stand
21、ard Solution (0.1000 N)7.6.1 Dissolve 4.9035 g of Primary Standard Grade potassium dichromate (K2Cr2O47) in water, transfer to a 1-L volumetricflask, dilute to volume, and mix.7.7 Sodium Diphenylamine Sulfonate Indicator Solution (2 g/L).7.7.1 Dissolve 0.20 g of sodium diphenylamine sulfonate in 100
22、 mL of water. Store in a dark-colored bottle.7.8 Sodium Pyrosulfate (Na2S2O7).8. Hazards8.1 For precautions to be observed in this method, refer to Practices E50.8.1.1 WarningCaution should be used for HF in 10.2.8.1.2 WarningCaution should be used for H2S in 10.5.9. Sampling and Sample Preparation9
23、.1 The test unit shall be collected and prepared to maintain the representative iron content in the lot.9.2 The laboratory sample shall be pulverized to pass a No. 100 (150-m)150-um (No. 100) sieve.9.3 Weigh approximately (within 6 25 mg) an amount of test sample specified as follows:Content of Iron
24、, % Weight of Sample, gContent of Iron, % Mass of Sample, g2 to 10 2.010 to 20 1.010. Procedure10.1 Transfer the test sample to a small, dry weighing bottle and place into a drying oven. After drying at 120 C for 1 h, capthe bottle and cool to room temperature in a desiccator. Momentarily release th
25、e cap to equalize pressure and weigh the cappedbottle to the nearest 0.1 mg. Repeat the drying and weighing until there is no further weightmass loss. Transfer the test sample toa 400-mL beaker and reweigh the capped bottle to the nearest 0.1 mg. The difference between the two masses is the mass of
26、thesample.10.2 Moisten the sample with a few millilitres of water, add 15 mL of HCl, cover and heat gently until no further attack isapparent. Add 5 mL of HNO3 and warm until the action subsides. Add 10 drops to 15 drops of HF and 15 mL of H2SO4, and heatto copious fumes of SO3 (do not prolong fumin
27、g). Cool, rinse the sides of the beaker with a few millilitres of water, and againheat to fumes of SO3. Cool, add 100 mL of water, and heat to boiling.3 Reagent Chemical,Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of
28、reagents notlisted by theAmerican Chemical Society, seeAnalar Standards for Laboratory Chemicals, BDH Ltd., Poole Dorset, U. K., and the United States Pharmacopeia and NationalFormulary, U.S. PharmaceuticalPharmacopeial Convention, Inc.,Inc. (USPC), Rockville, MDMD.E316 17210.3 Filter off any residu
29、e through a medium texture paper into a 400-mLbeaker and wash the paper and residue with hot wateruntil the iron color is removed from the paper. Reserve the 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 4 dropsof H2SO4
30、 (1 + 1) and 5 mL of HF. Evaporate slowly to expel the silica and the excess H2SO4.Add 3 g of Na2S2O7 to the crucibleand fuse over a burner until a clear melt is obtained. Dissolve the cool melt in a few millilitres of water and add this solution andthe washings of the crucible and cover to the rese
31、rved filtrate.10.5 Dilute the solution with water to a volume of 250 mL and heat to boiling. Remove from the heat source and pass a rapidstream of H2S through the solution for 15 min. Digest at 60 C for 15 min and filter through a medium texture paper with the aidof paper pulp into a 500-mL Erlenmey
32、er flask. Wash the precipitated sulfides thoroughly with the hydrogenH2 sulfide S washsolution. Add a few glass beads to the flask to prevent bumping, heat the solution to boiling, and boil for 15 min to 20 min tocompletely expel the H2S. (Check with lead acetate test paper.) Remove from the heat so
33、urce, cover the flask with a small watchglass, and cool to 20 C in running water.10.6 To the cool solution add 5 mL of H3PO4 and 5 drops of the sodium diphenylamine sulfonicsulfonate indicator solution.Dilute with water to approximately 300 mL and titrate with the standard K2Cr2O7 solution to a dist
34、inct purple end point.11. Blank Determination11.1 Determine the blank value of the reagents concurrently with the test determination, using the same amount of all reagentsand following all the steps of the procedure. Immediately before titrating with the K2Cr2O7 solution, add 1.0 mL, accuratelymeasu
35、red, of the FeSO4(NH4)2SO46H2O solution. In another beaker place 350 mL of cold H2SO4 (1 + 19) and add an accuratelymeasured 1 mLof the FeSO4(NH4)2SO46H2O solution.Add 5 mLof sodium diphenylamine sulfonate indicator solution and titratewith the K2Cr2O7 solution. Record this titration and subtract fr
36、om the titration of the blank solution to obtain the corrected blank.NOTE 2In the absence of iron, the sodium diphenylamine sulfonate indicator does not react with the K2Cr2O7 solution. The addition of theFeSO4(NH4)2SO46H2O is, therefore, necessary to promote indicator response in the blank solution
37、.Acorrection must be made in terms of its equivalentin millilitres of K2Cr2O7 solution.12. Calculation12.1 Calculate the iron content as follows:Iron,%5FA 2B!3CD G 3100 (1)where:A = millilitres of K2Cr2O7 solution required for titration of sample,B = millilitres of K2Cr2O7 solution required for titr
38、ation of blank,C = iron value of K2Cr2O7 in grams per millilitre, andD = grams of sample used.12.2 Rounding of test results obtained using this test method shall be performed in accordance with Practice E29, RoundingMethod, unless an alternative rounding method is specified by the customer or applic
39、able material specification.13. Precision and Bias13.1 PrecisionTable 1 indicates the precision of this test method between laboratories using standard samples as theunknowns.13.2 BiasNo information on the bias of this test method is known. Accepted values for the reference materials used in theinte
40、rlaboratory study arewere not available for evaluation. Users of the method are encouraged to employ accepted referencematerials, if available, and to judge the bias of the method from the difference between the accepted value for the iron content andthe mean value of the reference material.TABLE 1
41、Statistical InformationAverage IronContent,A%Relative StandardDeviation, %Number ofDeter-minationsNumber ofParticipatingLaboratories5.18 0.7 17 85.57 1.6 17 8A Each average iron content represents a different kind of manganese ore.E316 17314. Keywords14.1 dichromate titrimetry; iron content; mangane
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