1、Designation: D 3610 00 (Reapproved 2004)Standard Test Method forTotal Cobalt in Alumina-Base Cobalt-Molybdenum Catalystby Potentiometric Titration Method1This standard is issued under the fixed designation D 3610; the number immediately following the designation indicates the year oforiginal adoptio
2、n or, 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 cobalt(expressed as the oxide
3、) in fresh cobalt-molybdenum catalyst,in the range of 0.5 to 10 % cobalt oxide.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 of this standard to establish appro-priate safety and health practices and deter
4、mine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2E 50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE 173 Practice for Conducting
5、Interlaboratory Studies ofMethods for Chemical Analysis of Metals33. Summary of Test Method3.1 The sample is decomposed by adding water and sulfuricacid and then heating until completely dissolved. The coldsolution is diluted with water and transferred to a 250-mLvolumetric flask. An aliquot of this
6、 solution containing be-tween 10 and 30 mg of cobalt is transferred to a 250-mL beakercontaining measured volumes of potassium ferricyanide andammonium citrate solutions, ammonia, and petroleum ether.The excess of ferricyanide is then back-titrated with a standardcobalt solution.4. Significance and
7、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 find this test method to be of value.5. Interferences5.1 None of the elements normally found in fresh
8、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 interfere).6. Apparatus6.1 Analytical Balance and WeightsThe balance used toweigh the sample s
9、hall 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 ferricyanide and standard cobalt solutions shall be ofprecision grade and shall be read to 0.01 mL by
10、 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 acid and thoroughly rinsed with water.6.4 Potentiometric Titration ApparatusApparatus No. 3Bof
11、 Practices E 50, 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, it is intended thatall reagents shall conform to the specifications of the Commit-tee
12、 on Analytical Reagents of the American Chemical Society,where 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.1This test method is under t
13、he jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.03 on ChemicalComposition.Current edition approved April 1, 2004. Published April 2004. Originallyapproved in 1977. Last previous edition D 361000.2For referenced ASTM standards, visit the ASTM web
14、site, 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.3Withdrawn.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington,
15、DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual 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 I
16、nternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water conformingto Specification D 1193, Type IV.7.3 Ammonium Citrate Solution (680 g/L)Dissolve 680
17、 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 vol
18、umetric flask, dilute to volume, andmix. Since cobalt nitrate may not always be stoichiometric, itscontent may be checked versus high-purity cobalt metal(99.9 % purity).7.6 Petroleum Ether, b.p. 60 to 110C.7.7 Potassium Ferricyanide Solution (1 mL ; 1.494 mg ofCoO):7.7.1 Dissolve 6.58 g of potassium
19、 ferricyanide K3Fe(CN)6in water and dilute to 1 L. Store the solution in a dark-coloredbottle. Standardize the solution just before use as follows:Transfer from a 50-mL buret approximately 25 mL ofK3Fe(CN)6solution to a 250-mL beaker. Record the interpo-lated buret reading to the nearest 0.01 mL. Ad
20、d 25 mL ofammonium citrate solution, 90 mL of concentrated ammonia,and stir. Cool to 5 to 10C and maintain this temperature duringthe titration. Cover the solution with a layer of 10 mL ofpetroleum ether. Transfer the beaker to a potentiometric titra-tion apparatus. While stirring, titrate the K3Fe(
21、CN)6solutionwith cobalt standard solution (1 mL = 1.494-mg CoO) using a50-mL buret. Titrate at a fairly rapid rate until the end point isapproached and then add the titrant in one drop incrementsthrough the end point. After the addition of each increment,record the buret reading and voltage when equ
22、ilibrium isreached. Estimate the buret reading at the end point to thenearest 0.01 mL by interpolation.7.7.2 Calculate the cobalt oxide equivalent as follows:CoO equivalent, mg/mL 5 X 3 Y!/Z (1)where:X = millilitres of cobalt standard solution required totitrate the potassium ferricyanide solution,Y
23、 = milligrams of CoO per millilitre of standard solution,andZ = millilitres of potassium ferricyanide solution.Triplicate values should be obtained for the cobalt oxideequivalent. The values obtained should check within 1 to 2parts per thousand.7.8 Sulfuric Acid (sp. gr. 1.84)Concentrated sulfuric a
24、cid(H2SO4).8. Sample Preparation8.1 Pulverize the analytical sample to pass a No. 100(150-m) sieve. Ignite the pulverized sample for 30 min at550C in a muffle furnace. Allow to cool in a desiccator.9. Procedure9.1 Transfer a 4.5-g sample, weighed to the nearest 1 mg, toa 250-mL beaker. Moisten with
25、25 mL of water, add slowly 40mL of concentrated sulfuric acid, and stir. Cover the beaker andheat, using a hot plate or a Bunsen burner, until the sample iscompletely decomposed. (Silica, if present, will not dissolve.)Allow to cool and dilute to about 200 mL with distilled water.Allow to cool, tran
26、sfer into a 250-mL volumetric flask, diluteto volume, and mix.9.2 Prepare in a 250-mL beaker a mixture of the following:25.0 mL of ferricyanide solution measured to the nearest 0.01mL, 25 mL of ammonium citrate solution, and 90 mL ofconcentrated ammonia. Stir the mixture and cover with 10 mLof petro
27、leum ether.9.3 Cool to 5 to 10C, transfer the beaker to a potentiomet-ric titration apparatus, and maintain the 5 to 10C temperatureduring the titration.9.4 While stirring, transfer, using a pipet, from the 250-mLvolumetric flask an aliquot containing between 10 and 30 mgof CoO.9.5 Using a 50-mL bur
28、et, titrate the excess K3Fe(CN)6withthe cobalt solution (1 mL = 1.494-mg CoO) at a fairly rapidrate until the end point is approached, and then add the titrantin one-drop increments through the end point.NOTE 1For a successful titration, the sample solution must be addedto the excess K3Fe(CN)6soluti
29、on and not vice versa.9.6 After the addition of each increment, record the buretreading and voltage when equilibrium is reached. Estimate theburet reading at the end point to the nearest 0.01-mL interpo-lation.10. Calculation10.1 Calculate the percentage of cobalt oxide as follows:Cobalt oxide, % 5
30、AB 2 CD!/E# 3 100 (2)where:A = millilitres of standard potassium ferricyanide solution,B = cobalt oxide equivalent of the standard potassiumferricyanide solution,C = millilitres of cobalt standard solution,D = concentration of cobalt standard solution (mg CoO/mL), andE = milligrams of sample used.TA
31、BLE 1 Statistical InformationTest SampleCoO Found,%Repeatability(R1, E 173)Reproducibility(R2, E 173)1. SN-4318 (nominal 3 % CoO, 15 % MoO3) 3.72 0.17 % CoO 0.22 % CoO2. SN-4319 (nominal 6 % CoO, 12 % MoO3) 5.58 0.12 % CoO 0.19 % CoOD 3610 00 (2004)211. Precision511.1 Seven laboratories participated
32、 in supplying data underthe conditions outlined in Practice E 173. Statistical datacalculated in accordance with this procedure are presented inTable 1.12. Keywords12.1 alumina-base catalysts; cobalt; molybdenum;potentiometricASTM International takes no position respecting the validity of any patent
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35、s will receive careful consideration at a meeting of theresponsible technical committee, which you 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 b
36、y 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).5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR: D32-1001.D 3610 00 (2004)3
