1、Designation: D4464 10Standard Test Method forParticle Size Distribution of Catalytic Material by Laser LightScattering1This standard is issued under the fixed designation D4464; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear 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 the particlesize distribution of catalyst and catalyst carrier par
3、ticles and isone of several found valuable for the measurement of particlesize. The range of average particle sizes investigated was from1 to 300 m equivalent spherical diameter. The technique iscapable of measuring particles above and below this range. Theangle and intensity of laser light scattere
4、d by the particles areselectively measured to permit calculation of a volume distri-bution using light-scattering techniques.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 o
5、f 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 limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D3766 Terminology Relat
6、ing to Catalysts and CatalysisE105 Practice for Probability Sampling of MaterialsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Metho
7、dE1617 Practice for Reporting Particle Size CharacterizationData3. Terminology3.1 Definitions and recommended nomenclature pertainingto catalysts and to materials used in their manufacture can befound in Terminology D3766.3.2 Definitions of Terms Specific to This Standard:3.2.1 backgroundextraneous
8、scattering of light by mate-rial present in the dispersion fluid other than the particles to bemeasured. It includes scattering by contamination in themeasurement path.3.2.2 Fraunhofer Diffractionthe optical theory that de-scribes the low-angle scattering of light by particles that arelarge compared
9、 to the wavelength of the incident light.3.2.3 Mie Scatteringthe complex electromagnetic theorythat describes the scattering of light by spherical particles. It isapplied when the sample includes particles with diameters thatare close to the wavelength of the incident light. The real andimaginary in
10、dices of light refraction of the particles are needed.3.2.4 multiple scatteringthe re-scattering of light by aparticle in the path of light scattered by another particle. Thisusually occurs in heavy concentrations of a particle dispersion.4. Summary of Test Method4.1 Aprepared sample of particulate
11、material is dispersed inwater or a compatible organic liquid and is circulated throughthe path of a laser light beam or some other suitable source oflight. The particles pass through the light beam and scatter it.Photodetector arrays collect the scattered light which is con-verted to electrical sign
12、als to be analyzed using FraunhoferDiffraction, or Mie Scattering, or both. Scattering information,typically, is analyzed assuming a spherical geometry for theparticles. Calculated particle sizes are, therefore, presented asequivalent spherical diameters.5. Significance and Use5.1 It is important to
13、 recognize that the results obtained bythis test method or any other method for particle size determi-nation utilizing different physical principles may disagree. Theresults are strongly influenced by physical principles employedby each method of particle size analysis. The results of anyparticle si
14、zing method should be used only in a relative sense1This test method is under the jurisdiction of ASTM Committee D32 onCatalysts and is the direct responsibility of Subcommittee D32.02 on Physical-Mechanical Properties.Current edition approved Oct. 15, 2010. Published January 2011. Originallyapprove
15、d in 1985. Last previous edition approved in 2005 as D446400(2005).DOI: 10.1520/D4464-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summ
16、ary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.and should not be regarded as absolute when comparing resultsobtained by other methods. Particularly for fine materials (thatis, average particle size 20 m),
17、 significant differences areoften observed for laser light scattering instruments of differentmanufacturers. These differences include lasers of differentwavelengths, detector configuration, and the algorithms used toconvert scattering to particle size distribution. Therefore,comparison of results f
18、rom different instruments may bemisleading.35.2 Light scattering theories (Fraunhofer Diffraction4andMie Scattering5) that are used for determination of particle sizehave been available for many years. Several manufacturers oftesting equipment now have units based on these principles.Although each t
19、ype of testing equipment utilizes the samebasic principles for light scattering as a function of particlesize, different assumptions pertinent to application of thetheory and different models for converting light measurementsto particle size, may lead to different results for each instru-ment. Furth
20、ermore, any particles which are outside the sizemeasurement range of the instrument will be ignored, causingan increase in the reported percentages within the detectablerange. A particle size distribution which ends abruptly at thedetection limit of the instrument may indicate that particlesoutside
21、the range are present. Therefore, use of this test methodcannot guarantee directly comparable results from differenttypes of instruments.5.3 This test method can be used to determine particle sizedistributions of catalysts and supports for materials specifica-tions, manufacturing control, and resear
22、ch and developmentwork.5.4 For fine materials (that is, average particle size 20m), it is critical that Mie Scattering Theory be applied. Thisinvolves entering an “optical model” consisting of the “real”and “imaginary” refractive indices of the solid at the wave-length of the laser. The “imaginary”
23、refractive index is alsoreferred to as the “absorbance,” as it has a value of zero fortransparent materials such as glass beads. For common mate-rials and naturally occurring minerals (for example, kaolin),these values are known and published, and usually included inthe manufacturers instrument manu
24、al (for example, as anappendix). For example, kaolinite measured at 589.3 nm has a“real” refractive index of 1.55. The absorbance (imaginarycomponent) for minerals and metal oxides is normally taken as0.001, 0.01 or 0.1. Many of the published values weremeasured at 589.3 nm (sodium light) but often
25、values at otherwavelengths are also given. Extrapolation, interpolation, orestimation to the wavelength of the laser being used cantherefore be made.66. Interferences6.1 Air bubbles entrained in the circulating fluid will scatterlight and then be reported as particles. Circulating fluids,typically,
26、do not require degassing, but should be bubble-freeon visual inspections.6.2 Contaminants, such as non-aqueous solvents, oil orother organic coatings on the sample may emulsify in anaqueous carrier, scatter light, and be reported as part of theparticle size distribution. Samples containing such cont
27、ami-nants may be analyzed in a non-aqueous carrier solvent todissolve the contaminants or washed free of the contaminantwith a compatible aqueous solvent.6.3 Reagglomeration or settling of particles during analysiswill cause erroneous results. Dispersions shall be preparedsuch that a stable dispersi
28、on is maintained throughout theanalysis.6.4 Insufficient sample loading may cause electrical noiseinterference and poor data reproducibility. High sample load-ing may cause excessive light attenuation and multiple scatter-ing, resulting in erroneous particle size distributions.7. Apparatus7.1 Partic
29、le Size Analyzer, based on Fraunhofer Diffractionor Mie Scattering, or both, light scattering analysis techniques.Ensure that the analyzer system or subsystem is optimum forthe range of the powder being tested.7.2 Micro Sample Splitter, used in accordance withMNL 327to obtain the test portion of sam
30、ple.7.3 Ultrasonic Probe or Bath, if needed, to ensure disper-sion of agglomerates prior to analysis.8. Reagents and Materials8.1 The selected liquid carrier shall:8.1.1 Be compatible with the construction materials of thesample delivery system.8.1.2 Not cause dissolution or clumping of the particle
31、s.8.1.3 Be sufficiently clean to achieve acceptable backgroundlevels.8.2 The use of surfactant(s) is often recommended byequipment manufacturers. However, agents such as surfactants,antifoams, and viscosity modifiers should be used with caution.An interlaboratory study of this test method showed tha
32、t theuse of different types and concentrations of surfactant cansignificantly affect the results. In calculating the precision ofthis test method, results obtained using surfactants wereexcluded because they contributed disproportionately to thescatter in results. Comparisons between laboratories sh
33、ould beperformed with liquid carriers which are identical in allrespects.9. Sampling and Sample Size9.1 A representative test sample shall be obtained accordingto Practice E105. The test portion shall be extracted from thetest sample using a micro sample splitter according toMNL 32.7Quartering shall
34、 not be used.3Jillavenkatesa, A., et al., Particle Size Characterization, NIST RecommendedPractice Guide SP 960-1, 2001.4Born, M., and Wolf, E., Principles of Optics, Chapter 8, Pergamon Press,Oxford, 1957.5van Hulst, H. C., Light Scattering by Small Particles, Chapter 9, John Wileythe details are g
35、iven inASTM Research Report RR:D32-1041.1014.3.1 Repeatability Limit, (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more than the “r” value for that material; “r” is theinterval representing the critical difference between two testresults for the s
36、ame material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.14.3.1.1 Repeatability limits are listed in Tables 1-3.14.3.2 Reproducibility Limit, (R)Two test results shall bejudged not equivalent if they differ by more than the “R” valuefor that material;
37、 “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.14.3.2.1 Reproducibility limits are listed in Tables 1-3.14.3.3 The above terms (repeatability limit and reproduc
38、-ibility limit) are used as specified in Practice E177.14.3.4 Any judgment in accordance with statements in14.3.1 and 14.3.2 would normally have an approximate 95%probability of being correct, however, since all requestedreplicates were not consistently reported, there may be timeswhen differences g
39、reater than predicted by the ILS resultsarise, sometimes with considerably greater or smaller fre-quency that the 95% probability limit would imply.14.3.4.1 The ratio of the reproducibility to repeatability(R/r) is reported. As this ratio increases it indicates that whilethe intralaboratory precisio
40、n may be very good, the agreementamong laboratories decreases. High ratios can indicate sensi-tivity of precision to different instruments and software, as wellas any other procedural differences among different laborato-ries. The data show that higher ratio values generally occur forthe fine sample
41、s (C, D, E, F). As expected, differences amonginstruments are emphasized at smaller particle sizes.14.4 BiasAt the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod; therefore, no statement on bias is being made.14.5 The precision statem
42、ent was determined through sta-tistical examination of 378 results, from eight data sets fromsix different organizations. The six materials tested wereidentified as the following:Material A: FCC Catalyst: X-5388Material B: FCC Catalyst: X-6705Material C: Alumina Calcined: 5126Material D: Alumina Cal
43、cined: 6027Material E: Hydrous Kaolin: Ansilex-93Material F: Hydrous Kaolin: Lustra15. Keywords15.1 catalyst; Fraunhofer Diffraction; laser light scattering;Mie ScatteringTABLE 1 Fraction Smaller than 10 volume %Material AverageDiameterA(m)Repeatability,Standard DeviationReproducibility,Standard Dev
44、iationRepeatabilityLimitReproducibilityLimitPrecisionSensitivityx srSR r R R/rA 25.8 0.511 1.59 1.43 4.46 3.11B 39.6 2.70 5.06 7.57 14.2 1.87C 3.39 0.053 2.00 0.149 5.59 37.5D 2.27 0.073 1.26 0.205 3.52 17.2E 1.36 0.122 0.678 0.341 1.90 5.57F 1.39 0.033 0.975 0.093 2.73 29.4AThe average of the labor
45、atories calculated averages.D4464 104ASTM 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 any such patent rights, and the ri
46、skof 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 invited either for revision of th
47、is standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments 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
48、 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
49、 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 2 Fraction Smaller than 50 volume %Material AverageDiameterA(m)Repeatability,Standard DeviationReproducibility,Standard DeviationRepeatabilityLimitReproducibilityLimitPrecisionSensitivityx srSR r R R/rA 50.1 1.61 2.02 4.52 5.64 1.25B 81.6 0.639 4.43 1.79 12.4 6.92C 9.4 0.108 1.84 0.301 5.16 17.1D 7.
