1、Designation: D 7085 04e1Standard Guide forDetermination of Chemical Elements in Fluid CatalyticCracking Catalysts by X-ray Fluorescence Spectrometry(XRF)1This standard is issued under the fixed designation D 7085; 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.e1NOTETable 2 was corrected editorially in July 2005.1. Scope1.1 This guide covers sev
3、eral comparable procedures for thequantitative chemical analysis of up to 29 elements in fluidcatalytic cracking (FCC) catalyst by X-ray fluorescence spec-trometry (XRF). Additional elements may be added.1.2 This guide is applicable to fresh FCC catalyst, equilib-rium FCC catalyst, spent FCC catalys
4、t, and FCC catalyst fines.1.3 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 determine the applica-bility of regulatory requirements p
5、rior to use.2. Referenced Documents2.1 ASTM Standards:2C 982 Guide for Selecting Components for Energy-Dispersive X-ray Fluorescence (XRF) SystemsC 1118 Guide for Selecting Components for Wavelength-Dispersive X-ray Fluorescence (XRF) SystemsD 1977 Test Method for Nickel and Vanadium in FCCEquilibri
6、um Catalysts by Hydrofluoric/Sulfuric Acid De-composition and Atomic Spectroscopic AnalysisE 1172 Practice for Describing and Specifying aWavelength-Dispersive X-ray SpectrometerE 1361 Guide for Correction of Interelement Effects inX-ray Spectrometric AnalysisE 1621 Guide for X-ray Emission Spectrom
7、etric AnalysisE 1622 Practice for Correction of Spectral Line Overlap inWavelength-Dispersive X-ray Spectrometry3. Summary of Guide3.1 The test specimen is prepared with a clean, uniform, flatsurface. Two commonly used test methods of preparing testspecimens are listed: briquetting a powder (Test Me
8、thod A,Sections 8-15) and fusing a powder into a glass bead (TestMethod B, Sections 16-23). This surface of the fused orbriquetted specimen is irradiated with a primary source of Xrays. The secondary X rays produced in the specimen arecharacteristic of the chemical elements present in the speci-men.
9、 Two types of XRF instrumentation may be used to collectand process the X-ray spectra. Using a wavelength-dispersiveX-ray spectrometer, the secondary X rays produced in thespecimen are dispersed according to their wavelength bymeans of crystals or synthetic multilayers. The X-ray intensi-ties are me
10、asured by detectors set at selected wavelengths andrecorded as counts (number of X rays impinging on thedetector per unit time). Concentrations of the elements aredetermined from the measured intensities using calibrationcurves prepared from suitable reference materials. Using anenergy-dispersive X-
11、ray spectrometer, the secondary X raysproduced in the specimen are sent to a detector where the entireX-ray spectrum is electronically sorted according to the X-rayenergy and processed into counts using a multichannel ana-lyzer. The principal advantages of the wavelength-dispersiveX-ray spectrometer
12、 are resolution and detection limit. Theprincipal advantages of the energy-dispersive X-ray spectrom-eter are speed and a generally lower equipment cost.4. Significance and Use4.1 The chemical composition of fresh FCC catalyst andequilibrium FCC catalyst is a predictor of catalyst perfor-mance. The
13、analysis of catalyst fines also provides informationon the performance of the FCC unit and the fines collectiondevice(s).4.2 The chemical composition of equilibrium FCC catalystis a measure of the hazardous nature or toxicity of the materialfor purposes of disposal or secondary use.1This guide is un
14、der the jurisdiction of ASTM Committee D32 on Catalysts andis the direct responsibility of Subcommittee D32.03 on Chemical Composition.Current edition approved Nov. 1, 2004. Published November 2004.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
15、at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Apparatus5.1 X-ray Spectrometer, wavelength o
16、r energy-dispersivesystem equipped with a vacuum sample chamber. Refer toGuide C 982, Guide C 1118, and Practice E 1172 for informa-tion on specifying XRF systems.5.2 Muffle Furnace, capable of operating at 600C.5.3 Hot Plate, capable of maintaining a constant 200C.5.4 Porcelain Dishes, of a suitabl
17、e size for calcining 50-gsample aliquots.5.5 Vacuum Oven, capable of maintaining 60C. This isrequired only if catalyst fines are to be analyzed.5.6 Vacuum Desiccators, useful for storing fusion beads orpressed pellets.5.7 Fusion Equipment:5.7.1 Fusion Furnace or Fluxing Device, capable of oper-ating
18、 at 1100C.5.7.2 Fusion Crucibles and Molds, graphite or plati-num5 % gold alloy, sized to match the specimen holder of theX-ray spectrometer.5.8 Pressed Pellet Equipment:5.8.1 Grinders or Pulverizers, manual (such as agate, mul-lite, alumina, tungsten carbide, or boron carbide mortar andpestle) or a
19、utomated (typically with a tungsten carbide grindingvessel). Avoid steel grinding vessels.5.8.2 Mixer Mill, useful for blending ground sample andbinder prior to preparing a pressed powder specimen.5.8.3 Mixing Vials, sized to match the mixer mill.5.8.4 Briquetting Press, capable of maintaining a rep
20、roduc-ible pressure of at least 25 000 psi. This is required only if thepressed powder method is utilized. Match mold size to thespecimen holder of the X-ray spectrometer. Typical sizes are 25to 40 mm.6. Reagents6.1 Reagents for Fusion Techniques:6.1.1 Fluxes, lithium borates or carbonates or mixtur
21、es, ofultrahigh purity.6.1.2 Non-Wetting Agents, such as lithium or ammoniumiodide, are frequently added to the flux, as are oxidizing agentssuch as lithium, potassium, or ammonium nitrate. Take carethat adding non-wetting or oxidizing reagents does not causespectral interference with the analytes o
22、f interest.6.2 Reagents for Pressed Pellet Techniques:6.2.1 Heavy Absorber, barium or hafnium oxides are com-monly used as heavy absorbers, if that technique is applied.6.2.2 Binders, required for the pressed powder technique.These should not contribute any spectral interference. Micro-crystalline w
23、ax or cellulose with negligible levels of sodium orpotassium are suitable.6.3 Detector Gas, for a wavelength dispersive system. Thetypical gas for the flow-proportional counter is P-10: 10 %methane and 90 % argon.6.4 2-propanol, ACS reagent grade.6.5 Calibration References, commercially available st
24、an-dard or certified reference materials or locally prepared mix-tures from ultra high purity materials that include the elementsof interest in the concentration ranges expected in unknownsamples.6.6 Standard Solutions, 10 000 g/mL of nickel and 10 000g/mL of vanadium.7. Procedure7.1 Prepare specime
25、ns using either a pressed powder or afusion technique.7.2 Prepare calibration standards using the same techniquesand reagents that will be used with the unknown samples.7.2.1 Calibration standards can be prepared from previouslyanalyzed samples where the accuracy and precision of theanalysis is know
26、n. This is the typical calibration method for thepressed powder technique. Up to 100 analyzed standards maybe required for a full range calibration for 29 elements usingthe pressed powder technique.7.2.2 Synthetic standards can be prepared from reagent-grade chemicals, analyzed samples, and certifie
27、d referencematerials. This is the typical calibration method for the fusiontechnique.7.3 Several tables, listed in Appendix X1, provide operatinginformation on the requirements necessary to establish apressed powder method for 29 elements in equilibrium FCCcatalyst.TEST METHODSTest Method APressed P
28、owder8. Scope8.1 A test method example is provided for the analysis ofnickel and vanadium in equilibrium FCC catalyst using eithera wavelength or an energy-dispersive X-ray spectrometer andtest specimens prepared by the pressed pellet technique.8.2 This technique can be extended to other elements.9.
29、 Significance and Use9.1 In use, the FCC catalyst becomes contaminated withmetals present in the feed oil. The levels of the contaminantmetals, particularly the catalyst poisons nickel and vanadium,can be used to predict catalyst performance.10. Hazards10.1 Catalyst dust.10.2 X-ray radiation.10.3 He
30、at.10.4 High pressure.11. Preparation of Apparatus11.1 Select the appropriate instrument for either awavelength-dispersive or energy-dispersive technique. Forthese examples, use of energy-dispersive systems for analytesbelow 1000 ppm would prove difficult. Assuming the FCCcatalyst contains rare eart
31、hs, the difficulty increases because,by energy-dispersive X-ray fluorescence spectrometry(EDXRF), rare earths are poorly resolved and create significantmatrix effects.11.2 Read Guide E 1621, Guide E 1361, and PracticeE 1622. These will provide a general knowledge of thefunction of a wavelength-dispe
32、rsive X-ray spectrometer.D708504e1211.3 Set up the instrument using the vendors manual.Modern X-ray spectrometers are equipped with software thatguides the operator through the steps necessary to create ananalytical program for a specific analysis. For this example,analysis of equilibrium FCC for ni
33、ckel and vanadium, typicalinstrument conditions are given in Appendix X1.12. Calibration and Standardization12.1 Preparation of Calibration Standards:12.1.1 Assemble a minimum of five catalyst samples withnickel and vanadium concentrations that cover the range ofinterest. This test method is specifi
34、c for a single grade ofcatalyst and is limited to material where only the nickel andvanadium content varies.12.1.2 Prepare each catalyst sample in duplicate in accor-dance with Section 13, saving a portion of the calcined andground specimen for the next step.12.1.3 Determine the nickel and vanadium
35、content of thematerials prepared in 12.1.2 using a comparative analyticaltechnique such as Test Method D 1977.12.2 Calibrate the instrument using the prepared standardsfollowing the vendors recommended procedure.13. Preparation of the Test Specimen13.1 Heat approximately 50 g of specimen in a muffle
36、furnace at 600C with a bed depth less than 25 mm for aminimum of 1 h, if it is fresh catalyst, or up to3htoremovecarbon from spent catalyst, equilibrium catalyst, or catalystfines.13.2 Grind approximately 20 to 30 g of the heated specimento less than 30 m. Homogenize the material if it was groundin
37、several batches.13.3 Combine the ground specimen with binder at a prede-termined ratio into a mixing vial with mixing beads added topromote agitation. Typically, the binder is blended at a ratio of1 part binder to 3 to 5 parts sample and chosen to giveconsistent and stable pellets.NOTE 1As an exampl
38、e, 1.5 6 0.01 g of a micronized high molecularweight paraffin wax binder is mixed with 6.5 6 0.01 g of the groundspecimen.13.4 Place the mixing vial into a mixing mill for 10 min tothoroughly mix/blend the specimen and binder.13.5 Place the contents of the mixing vial onto a piece ofweighing paper.
39、Remove and discard the mixing beads.13.6 Transfer the contents of the weighing paper to thebriquetting press, which has been previously cleaned with2-propanol, and spread evenly over the surface of the mold oroptionally press into an aluminum cap.13.7 Press the specimen at a ram pressure of between2
40、5 000 and 60 000 psi. The pressure used will depend on thebinder and binder/sample ratio and is usually determinedempirically. For this binder example, a typical ram pressure is30 000 psi for 10 6 2 s for a 40-mm mold.13.8 Attach an identifying label to the backside of the pellet.Typically, the top
41、surface is the analytical surface. Avoidtouching this surface when handling the briquetted pellet.13.9 Store the pressed powder specimens in a vacuumdesiccator to prevent moisture pickup or contamination prior toanalysis.14. Procedure14.1 Analyze the prepared specimens following the ven-dors recomme
42、nded procedure using the calibration establishedpreviously in 12.2.15. Precision and Bias15.1 The precision values listed in Table 1 were obtainedfrom one sample of equilibrium FCC catalyst, prepared andanalyzed 16 times. The % relative standard deviation (RSD) isdefined as:%RSD 5 s / mean concentra
43、tion! 3 100Test Method BFused Bead16. Scope16.1 A test method example is provided for the analysis ofnickel and vanadium in equilibrium FCC catalyst using eithera wavelength or an energy-dispersive X-ray spectrometer andusing test specimens prepared by the fused bead technique.17. Significance and U
44、se17.1 In use, the FCC catalyst becomes contaminated withmetals present in the feed oil. The levels of the contaminantmetals, particularly the catalyst poisons nickel and vanadium,can be used to predict catalyst performance.18. Hazards18.1 Catalyst dust.18.2 Flux dust.18.3 Heat.TABLE 1 Precision Val
45、uesMean Concentration, % 62 s (95 % C.I.) %RSDAl2O329.92 0.16 0.27SiO265.48 0.49 0.37Ni 0.2332 0.0051 1.1V 0.2417 0.0028 0.58Fe 0.54 0.01 0.78Cu 0.0045 0.0002 1.7TiO21.03 0.01 0.49Mn 0.0040 0.0003 4.1Co 0.0142 0.0006 2.0Na 0.60 0.01 0.73MgO 0.085 0.004 2.5P2O50.340 0.009 1.2CaO 0.16 0.005 1.7SO40.17
46、 0.01 2.3Sb 0.0862 0.0013 0.77ZnO 0.0255 0.0007 1.4Pb 0.0077 0.0002 1.4Ba 0.030 0.002 3.3La2O30.84 0.01 0.47CeO20.37 0.01 1.3Nd2O30.42 0.01 0.93Pr6O110.13 0.01 2.3Sm2O30.01 0.001 6.0Total REO 1.77 0.01 0.60K2O 0.10 0.002 0.92Sr 0.011 0.001 2.9Zr 0.009 0.001 6.0D708504e1318.4 X-ray radiation.19. Prep
47、aration of Apparatus19.1 Select the appropriate instrument for either awavelength-dispersive or energy-dispersive technique. Forthese examples, use of energy-dispersive systems for analytesbelow 1000 ppm would prove difficult. Assuming the FCCcatalyst contains rare earths, the difficulty increases b
48、ecause,by EDXRF, rare earths are poorly resolved and create signifi-cant matrix effects.19.2 Read Guide E 1621, Guide E 1361, and PracticeE 1622. These will provide a general knowledge of thefunction of a wavelength-dispersive X-ray spectrometer.19.3 Set up the instrument using the vendors manual.Mo
49、dern X-ray spectrometers are equipped with software thatguides the operator through the steps necessary to create ananalytical program for a specific analysis. For this example,analysis of equilibrium FCC for nickel and vanadium, typicalinstrument conditions are given in Appendix X1.20. Calibration and Standardization20.1 Preparation of Calibration StandardsCalibrationwith the fused bead test method for only one or two elementsis generally simpler than with the pressed powder test method.If analyzed standard samples are available, they can be used.Usually this is not
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