1、Designation: E 247 01 (Reapproved 2005)Standard Test Method forDetermination of Silica in Manganese Ores, Iron Ores, andRelated Materials by Gravimetry1This standard is issued under the fixed designation E 247; the number immediately following the designation indicates the year oforiginal adoption o
2、r, 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 silica iniron ores, iron ore con
3、centrates and agglomerates, and manga-nese ore in the concentration range from 0.5 to 15 %.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user oi this standard to establish appro-priate safety and health practi
4、ces and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent WaterE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE 135 Terminology R
5、elating to Analytical Chemistry forMetals, Ores and Related MaterialsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE 877 Practice for Sampling and Sample Preparation of IronOres and Related MaterialsE 882 Guide for Accountability and Quality Control
6、 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 fused with sodium peroxide in a zirco-nium crucible. The melt is leached with water and dissolved inhydrochloric aci
7、d. Silica is separated by double dehydrationwith perchloric acid. The two precipitates are combined,ignited, and weighed. The silica is volatilized by treatment withhydrofluoric and sulfuric acids and the residue weighed.5. Significance and Use5.1 This test method is intended to be used for complian
8、cewith compositional specifications for silica content. It isassumed that all who use these procedures will be trainedanalysts capable of performing common laboratory proceduresskillfully and safely. It is expected that work will be performedin a properly equipped laboratory and that proper wastedis
9、posal procedures will be followed. Appropriate qualitycontrol practices must be followed such as those described inGuide E 882.6. Interferences6.1 This test method is written for iron and manganese orescontaining less than 0.25 % of fluorine. None of the elementsnormally found in iron ores or in man
10、ganese ores interfere withthis test method.7. Apparatus7.1 Zirconium Crucible (50-mL capacity).7.2 Platinum Filter Cone.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifi
11、cations of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specification are available.2Other 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.8.2 Purit
12、y of WaterUnless otherwise indicated, refer-ences to water shall be understood to mean reagent water asdefined by Type I of Specification D 1193.8.3 Hydrochloric Acid (sp gr 1.19)Concentrated hydro-chloric acid (HCl).8.4 Hydrochloric Acid (1 + 49)Mix 1 volume of concen-trated HCl (sp gr 1.19) with 4
13、9 volumes of water.1This test method is under 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 May 1, 2005.
14、 Published June 2005. Originallyapproved in 1964. Last previous edition approved in 2001 as E 247 01.2Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Anal
15、ar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8
16、.5 Hydrofluoric Acid (48 %)Concentrated hydrofluoricacid (HF).8.6 Perchloric Acid (70 %) (HClO4).8.7 Sodium Peroxide Powder (Na2O2).8.8 Sulfuric Acid (1 + 1)Carefully pour 1 volume ofconcentrated sulfuric acid (H2SO4, sp gr 1.84) into 1 volume ofwater.9. Hazards9.1 For precautions to be observed in
17、this method, refer toPractices E50.10. Sampling and Sample Preparation10.1 SamplingThe gross sample shall be collected andprepared in accordance with Practice E 877.10.2 Sample PreparationThe laboratory sample shall bepulverized to pass a No. 100 (150-m) sieve.NOTE 1To facilitate decomposition, some
18、 ores, such as specularhematite, require grinding to pass a No. 200 (75-m) sieve.10.3 Sample WeightWeigh approximately (within 625mg) an amount of test sample specified as following:Content of Silica, % Weight of Test Sample, gLess than 2 1.02 and over 0.511. Procedure11.1 Transfer the test sample t
19、o a small, dry weighing bottleand place in a drying oven. Dry iron ore samples at 110C andmanganese ore samples at 120C for 1 h. Cap the bottle andcool to room temperature in a desiccator. Momentarily releasethe cap to equalize pressure and weigh the capped bottle to thenearest 0.1 mg. Repeat the dr
20、ying and weighing until there isno further weight loss. Transfer the test sample to a zirconiumcrucible and reweigh the capped bottle to the nearest 0.1 mg.The difference between the two weights is the weight of the testsample.Add4gofsodium peroxide into the crucible. Mix witha stainless steel spatu
21、la.11.2 Fuse the contents over a low flame on a Meker burner,swirling the crucible. When the contents begin to melt, increasethe heat to cherry red. Swirl until a clear melt solidifies evenlyon the sides of the crucible. Cool for 1 to 2 min and place intoa 250-mL beaker. Cover with a watchglass. Cau
22、tiously add 10to 15 mL of water into the crucible. When the reaction ceases,empty the crucible contents and crucible rinsings into thebeaker.Add 25 mL HCl by means of the crucible. Finally, rinseand police crucible with water and add rinsings to the beaker.Heat to a boil to obtain a complete and cle
23、ar solution. Cool for1 to 2 min. Add 25 mL of HClO4. Cover with a watchglass andheat to dense white fumes in the perchloric acid fume hood.Fume for 15 to 20 min. Cool for 1 to 2 min. Add 50 mL ofwater containing 2 mL HCl (8.3) and heat the contents todissolve soluble salts. Filter through a fine-tex
24、tured paper withthe aid of paper pulp and a platinum filter cone using suction.Wash filter 5 times with hot HCl (1 + 49) (8.4) and then 10times with hot water, to remove all perchlorates (see Note 2).Reserve the filtrate. Transfer filter paper and residue to aplatinum crucible.NOTE 2The residue must
25、 be washed free of perchlorates to preventpossible loss of residue by deflagration during the ignition.11.3 Add 10 mL of HClO4to the reserved filtrate. Coverwith a watchglass and take to dense white fumes and continuefuming for 15 to 20 min. Cool for 1 to 2 min. Add 50 mL ofwater containing 2 mL of
26、HCl (8.3). Heat the contents todissolve soluble salts. Filter through a fine-textured paper withthe aid of paper pulp and a platinum cone using suction. Wash5 times with hot HCl (1 + 49) (8.4) and then 10 times with hotwater (Note 2). Combine the filter and residue with thereserved filter paper and
27、residue in the platinum crucible.11.4 Ignite crucible and contents at 500C for 1 h and thenat 1000C for 30 min. Cool in a desiccator. After 20 min,weigh.11.5 Add 6 drops of H2SO4(1+1) (8.8) to moisten thecontents of the crucible. Add 5 mL of HF. Cautiously andslowly heat to the absence of SO3fumes.
28、Ignite the residue ina muffle furnace at 1000C for 10 min. Cool in a desiccator.After 20 min, weigh. The difference in weight is the weight ofthe silica.12. Blank Determination12.1 Perform a blank determination using the same amountof reagents and performing the same operations described inthe test
29、procedure.13. Calculation13.1 Calculate the percentage of silica as follows:Silica, % 5 100 A 2 B!/Cwhere:A = silica in test sample, g,B = silica in blank, g, andC = test sample weight, g.14. Precision and Bias314.1 PrecisionTable 1 indicates the precision of the testmethod as determined by Practice
30、 E 691, but not extended toobtaining either the repeatability or reproducibility statistic3Supporting data are available from ASTM International Headquarters. RequestRR: E16 1005.TABLE 1 Statistical SummaryASampleBCertifiedConcentration, %AverageDetermination, %Standard DeviationWithin-LaboratoryBet
31、ween-LaboratoriesIron OreNBS 692 10.14 10.10 0.038 0.080NBS 27F 4.17 4.13 0.036 0.052NBS 693 3.87 3.86 0.044 0.045NBS 690 3.71 3.66 0.029 0.064Manganese OreNBS 25C 2.36 2.34 0.036 0.074Pooled standard deviationsC0.037 0.064ACalculations based on Practice E 691. Since there were only three cooperat-i
32、ng laboratories, no projection is made to determine repeatability or reproducibilityvalues.BEach concentration represents a different kind of iron ore.CRoot mean square of individual standard deviations.E 247 01 (2005)2since there were only duplicate determinations made by threecooperating laborator
33、ies. (Although one laboratory made qua-druplicate analyses on the manganese ore, it was treated as ifthey were only duplicates.)14.2 BiasThere was no significant bias in the determina-tions using samples that were all NIST certified referencematerials.15. Keywords15.1 agglomerates; analytical proced
34、ures; concentrates;gravimetric silica; iron ore; manganese ore; silicaASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of a
35、ny 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 revised, either reapproved or withdrawn. Your comments are
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37、ved 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 247 01 (2005)3
