1、Designation:D361000(Reapproved 2015)Standard Test Method forTotal Cobalt in Alumina-Base Cobalt-Molybdenum Catalystby Potentiometric Titration Method1This standard is issued under the fixed designation D3610;the number immediately following the designation indicates the year oforiginal adoption or,i
2、n the case 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 cobalt(expressed as the oxide)in fresh coba
3、lt-molybdenum catalyst,in the range of 0.5 to 10%cobalt oxide.1.2 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 theres
4、ponsibility of the user of 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:2D1193 Specification for Reagent WaterE50 Practices for Apparatus,Reagents,and Safety Consid
5、-erations for Chemical Analysis of Metals,Ores,andRelated MaterialsE173 Practice for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals(Withdrawn1998)33.Summary of Test Method3.1 The sample is decomposed by adding water and sulfuricacid and then heating until completely dis
6、solved.The coldsolution is diluted with water and transferred to a 250-mLvolumetric flask.An aliquot of this solution containing be-tween 10 and 30 mg of cobalt is transferred to a 250-mLbeakercontaining measured volumes of potassium ferricyanide andammonium citrate solutions,ammonia,and petroleum e
7、ther.The excess of ferricyanide is then back-titrated with a standardcobalt solution.4.Significance and Use4.1 This test method sets forth a procedure by whichcatalyst samples may be compared either on an interlaboratoryor intralaboratory basis.It is anticipated that catalyst producersand users will
8、 find this test method to be of value.5.Interferences5.1 None of the elements normally found in fresh cobalt-molybdenum catalysts interferes with this method.(Elementssuch as nickel,phosphorus,silicon,aluminum,and molybde-num do not interfere;elements such as iron,chromium,vanadium,and manganese do
9、interfere).6.Apparatus6.1 Analytical Balance and WeightsThe balance used toweigh the sample shall have a precision of 0.1 mg.Analyticalweights shall be of precision grade or calibrated against a set ofcertified standard weights.6.2 BuretThe 50-mL buret used to deliver the standardpotassium ferricyan
10、ide and standard cobalt solutions shall be ofprecision grade and shall be read to 0.01 mL by interpolation.6.3 GlasswareBeakers used in the analysis of the sampleshall be of chemical-resistant glass and free of etched surfaces.Before using,all glassware shall be cleaned in hot dilutehydrochloric aci
11、d and thoroughly rinsed with water.6.4 Potentiometric Titration ApparatusApparatus No.3Bof Practices E50,or equivalent.6.5 Hot PlateCapable of maintaining surface temperatureof at least 300C.7.Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,
12、it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,1This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.03 on ChemicalComposition.C
13、urrent edition approved Dec.1,2015.Published December 2015.Originallyapproved in 1977.Last previous edition approved in 2010 as D361000(2010).DOI:10.1520/D3610-00R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book
14、of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 where
15、such specifications are available.4Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean
16、 reagent water conformingto Specification D1193,Type IV.7.3 Ammonium Citrate Solution(680 g/L)Dissolve 680 gof diammonium hydrogen citrate(NH4)2HC6H5O7in 750 mLof water and dilute to 1 L.7.4 Ammonium Hydroxide(sp.gr.0.90)Concentrated am-monium hydroxide(NH4OH).7.5 Cobalt Standard Solution(1 mL=1.494 mg of CoO)Dissolve 5.80 g of cobalt nitrate Co(NO3)26H2O in 500 mL ofwater,transfer to a 1-L volumetric flask,dilute to volume,andmix.Since cobalt nitrate may not always be stoichiometric,itscontent