ASTM E342-2011 red 4375 Standard Test Method for Determination of Chromium Oxide in Chrome Ores by Permanganate Titrimetry 《用高锰酸钾滴定法测定铬矿石中氧化铬的标准试验方法》.pdf
《ASTM E342-2011 red 4375 Standard Test Method for Determination of Chromium Oxide in Chrome Ores by Permanganate Titrimetry 《用高锰酸钾滴定法测定铬矿石中氧化铬的标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM E342-2011 red 4375 Standard Test Method for Determination of Chromium Oxide in Chrome Ores by Permanganate Titrimetry 《用高锰酸钾滴定法测定铬矿石中氧化铬的标准试验方法》.pdf(4页珍藏版)》请在麦多课文档分享上搜索。
1、Designation:E34204 Designation:E34211Standard Test Method for Determination of Chromium Oxidein Chrome Ores by Permanganate Titrimetry1This standard is issued under the fixed designation E342; 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.Scope1.1This test method covers the determination of chromium oxide (Cr2O3) in chrome ores in the concentr
3、ation range from 25 to60%.1.2) in chrome ores in the compositional range from 25 % to 60 %.NOTE1As used in this test method, “%” refers to a mass fraction (wt/wt %) (g/100g).1.2The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1
4、.3This 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 and health practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Docume
5、nts2.1ASTM Standards:2D1193Specification for Reagent WaterE50Practices for Apparatus, Reagents, and Safety Considerations for Chemical Analysis of Metals, Ores, and Related MaterialsE135Terminology Relating to Analytical Chemistry for Metals, Ores, and Related MaterialsE276Test Method for Particle S
6、ize or Screen Analysis at No. 4 (4.75-mm) Sieve and Finer for Metal-Bearing Ores and RelatedMaterialsE882Guide for Accountability and Quality Control in the Chemical Analysis Laboratory3.Terminology3.1 DefinitionsFor definitions of terms used in this test method, refer to Terminology E135.4.Summary
7、of Test Method4.1The sample is decomposed by fusion with sodium peroxide. After leaching in water and boiling to decompose peroxides, thesolution is acidified with nitric and sulfuric acids. Residual chromium is oxidized to chromate with silver nitrate, potassiumpermanganate, and peroxydisulfate. Th
8、e excess of permanganate is destroyed by the addition of sodium chloride. After cooling,the chromate is reduced by the addition of a measured excess of a ferrous ammonium sulfate, and the excess is titrated with astandard permanganate solution.5.Significance and Use5.1This test method is intended to
9、 be used for compliance with compositional specifications for chromium oxide content inchromium-bearing ores. It is assumed that all who use these procedures will be trained analysts capable of performing commonlaboratory procedures skillfully and safely. It is expected that work will be performed i
10、n a properly equipped laboratory and thatproper waste disposal procedures will be followed. Appropriate quality control practices must be followed such as those describedin Guide E882.6.Interferences6.1None of the elements normally found in chrome ores interfere with this test method.1This test meth
11、od is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.02 on Ores, Concentrates, and Related Metallurgical Materials.Current edition approved MayDec. 1, 2004.2011. Published June 2004.Janu
12、ary 2012. Originally approved in 1967. Last previous edition approved in 19992004 asE34299.E34204. DOI: 10.1520/E0342-04.10.1520/E0342-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume
13、 information, refer to the standards Document Summary page on the ASTM website.1This document is not an ASTM standard and is intended only to provide 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 adequa
14、tely depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocke
15、n, PA 19428-2959, United States.7.Reagents and Materials7.1Purity 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 su
16、chspecifications are available3. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.7.2Purity of WaterUnless otherwise indicated, references to water shall be understood to me
17、an reagent water as defined byconforming to Type I or II of Specification D1193. . Type III or IV may be used if they effect no measurable change in the blankor sample.7.3Ammonium Peroxydisulfate Solution (250 g/L)Dissolve 25 g of ammonium persulfate (ammonium peroxydisulfate)(NH4)2S2O8) in water, a
18、nd dilute to 100 mL. Prepare fresh as needed.7.4Ferrous Ammonium Sulfate, Standard Solution7.4Ferrous Ammonium Sulfate Solution(0.2 N)Dissolve 78.4 g of ferrous ammonium sulfate (FeSO4(NH4)2SO46H2O) in 1L of cool H2SO4(5+95). As (5 + 95). Because the ferrous ammonium sulfate solution gradually weake
19、ns in reducing power, itis necessary to standardize it daily, the ferrous ammonium sulfate solution daily or at the same time that the chrome ore is analyzed.To standardize, transfer 100 mL of FeSO4(NH4)2SO46H2O to a 600-mL beaker, dilute to 300 mL with cold H2SO4(5 + 95), add2mLofH3PO4and 2 drops o
20、f ortho-phenanthroline ferrous sulfate (Fferroin). Titrate immediately with 0.2 N KMnO4solution(7.9) to a faint, permanent pink color.7.5Ferrous Sulfate Solution (0.025 M)Dissolve 6.95 g of ferrous sulfate (FeSO47H2O) in 500 mL of water and dilute to 1L.7.6Nitric Acid (sp gr 1.42)Concentrated nitric
21、 acid (HNO3).7.7Ortho-Phenanthroline Ferrous Sulfate Indicator Solution (0.025 M)Dissolve 1.485 g of 1,10-phenanthroline monohy-drate in 100 mL of ferrous sulfate solution (FeSO47H2O).7.8O) prepared in 7.5.7.7Phosphoric Acid (sp gr 1.69)(specific gravity 1.69 g/mL)Concentrated phosphoric acid (H3PO4
22、).7.97.8Potassium Permanganate Solution (20 g/L)Dissolve 20 g of potassium permanganate (KMnO4) in water and dilute to 1L.7.10Potassium Permanganate, Standard Solution7.9Potassium Permanganate Solution(0.2 N)Dissolve 6.4 g of KMnO4in 1 L of water. Standardize against the NationalInstitute of Standar
23、ds and Technology Standard sodium oxalate or equivalent.7.11in 1 L of water. Standardize against a National Institute of Standards and Technology Reference Material for sodium oxalate(Na2C2O4) or equivalent.7.10Silver Nitrate Solution (8 g/L)Dissolve8gofsilver nitrate (AgNO3) in water and dilute to
24、1 L.7.127.11Sodium Chloride Solution (100 g/L)Dissolve 10 g of sodium chloride (NaCl) in water and dilute to 100 mL.7.137.12Sodium Peroxide (Na2O2).7.14Sulfuric Acid (1+1)Carefully pour 1 volume of concentrated sulfuric acid (H2SO4, sp gr 1.84) into 1 volume of water.7.15Sulfuric Acid (5+95)Carefull
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