ASTM D4464-00(2005)
(Test Method)Standard Test Method for Particle Size Distribution of Catalytic Material by Laser Light Scattering
Standard Test Method for Particle Size Distribution of Catalytic Material by Laser Light Scattering
SIGNIFICANCE AND USE
It is important to recognize that the results obtained by this test method or any other method for particle size determination utilizing different physical principles may disagree. The results are strongly influenced by physical principles employed by each method of particle size analysis. The results of any particle sizing method should be used only in a relative sense and should not be regarded as absolute when comparing results obtained by other methods.
Light scattering theories (Fraunhofer Diffraction3 and Mie Scattering4 ) that are used for determination of particle size has been available for many years. Several manufacturers of testing equipment now have units based on these principles. Although each type of testing equipment utilizes the same basic principles for light scattering as a function of particle size, different assumptions pertinent to application of the theory and different models for converting light measurements to particle size, may lead to different results for each instrument. Furthermore, any particles which are outside the size measurement range of the instrument will be ignored, causing an increase in the reported percentages within the detectable range. A particle size distribution which ends abruptly at the detection limit of the instrument may indicate that particles outside the range are present. Therefore, use of this test method cannot guarantee directly comparable results from different types of instruments.
This test method can be used to determine particle size distributions of catalysts and supports for materials specifications, manufacturing control, and research and development work.
SCOPE
1.1 This test method covers the determination of the particle size distribution of catalyst and catalyst carrier particles and is one of several found valuable for the measurement of particle size. The range of particle sizes investigated was 30 to 300 μm equivalent spherical diameter. The technique is capable of measuring particles above and below this range. The angle and intensity of laser light scattered by the particles are selectively measured to permit calculation of a volume distribution using light-scattering techniques.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:D4464–00 (Reapproved 2005)
Standard Test Method for
Particle Size Distribution of Catalytic Material by Laser Light
Scattering
This standard is issued under the fixed designation D4464; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2 Definitions of Terms Specific to This Standard:
3.2.1 background—extraneous scattering of light by mate-
1.1 Thistestmethodcoversthedeterminationoftheparticle
rial present in the dispersion fluid other than the particles to be
size distribution of catalyst and catalyst carrier particles and is
measured. It includes scattering by contamination in the
one of several found valuable for the measurement of particle
measurement path.
size. The range of particle sizes investigated was 30 to 300 µm
3.2.2 Fraunhofer Diffraction—the optical theory that de-
equivalent spherical diameter. The technique is capable of
scribes the low-angle scattering of light by particles that are
measuring particles above and below this range.The angle and
large compared to the wavelength of the incident light.
intensity of laser light scattered by the particles are selectively
3.2.3 Mie Scattering—the complex electromagnetic theory
measured to permit calculation of a volume distribution using
that describes the scattering of light by spherical particles. It is
light-scattering techniques.
usually applied to particles with diameters that are close to the
1.2 This standard does not purport to address all of the
wavelength of the incident light. The real and imaginary
safety concerns, if any, associated with its use. It is the
indices of light refraction of the particles are needed.
responsibility of the user of this standard to establish appro-
3.2.4 multiple scattering—the re-scattering of light by a
priate safety and health practices and determine the applica-
particle in the path of light scattered by another particle. This
bility of regulatory limitations prior to use.
usually occurs in heavy concentrations of a particle dispersion.
2. Referenced Documents
4. Summary of Test Method
2.1 ASTM Standards:
4.1 Aprepared sample of particulate material is dispersed in
D3766 Terminology Relating to Catalysts and Catalysis
water or a compatible organic liquid and is circulated through
E105 Practice for Probability Sampling Of Materials
the path of a laser light beam or some other suitable source of
E177 Practice for Use of the Terms Precision and Bias in
light. The particles pass through the light beam and scatter it.
ASTM Test Methods
Photodetector arrays collect the scattered light which is con-
E456 Terminology Relating to Quality and Statistics
verted to electrical signals to be analyzed using Fraunhofer
E691 Practice for Conducting an Interlaboratory Study to
Diffraction, or Mie Scattering, or both. Scattering information,
Determine the Precision of a Test Method
typically, is analyzed assuming a spherical geometry for the
E1617 Practice for Reporting Particle Size Characterization
particles. Calculated particle sizes are, therefore, presented as
Data
equivalent spherical diameters.
3. Terminology
5. Significance and Use
3.1 Definitions and recommended nomenclature pertaining
5.1 It is important to recognize that the results obtained by
to catalysts and to materials used in their manufacture can be
this test method or any other method for particle size determi-
found in Terminology D3766.
nation utilizing different physical principles may disagree. The
results are strongly influenced by physical principles employed
This test method is under the jurisdiction of ASTM Committee D32 on
by each method of particle size analysis. The results of any
Catalysts and is the direct responsibility of Subcommittee D32.02 on Physical-
particle sizing method should be used only in a relative sense
Mechanical Properties.
andshouldnotberegardedasabsolutewhencomparingresults
Current edition approved Oct. 1, 2005. Published October 2005. Originally
approved in 1985. Last previous edition approved in 2000 as D4464–00. DOI:
obtained by other methods.
10.1520/D4464-00R05.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4464–00 (2005)
5.2 Light scattering theories (Fraunhofer Diffraction and 8. Reagents and Materials
Mie Scattering ) that are used for determination of particle size
8.1 The selected liquid carrier shall:
has been available for many years. Several manufacturers of
8.1.1 Be compatible with the construction materials of the
testing equipment now have units based on these principles.
sample delivery system.
Although each type of testing equipment utilizes the same
8.1.2 Not cause dissolution or clumping of the particles.
basic principles for light scattering as a function of particle
8.1.3 Besufficientlycleantoachieveacceptablebackground
size, different assumptions pertinent to application of the
levels.
theory and different models for converting light measurements
8.2 The use of surfactant(s) is often recommended by
to particle size, may lead to different results for each instru-
equipmentmanufacturers.However,agentssuchassurfactants,
ment. Furthermore, any particles which are outside the size
antifoams,andviscositymodifiersshouldbeusedwithcaution.
measurement range of the instrument will be ignored, causing
An interlaboratory study of this test method showed that the
an increase in the reported percentages within the detectable
use of different types and concentrations of surfactant can
range. A particle size distribution which ends abruptly at the
significantly affect the results. In calculating the precision of
detection limit of the instrument may indicate that particles
this test method, results obtained using surfactants were
outsidetherangearepresent.Therefore,useofthistestmethod
excluded because they contributed disproportionately to the
cannot guarantee directly comparable results from different
scatter in results. Comparisons between laboratories should be
types of instruments.
performed with liquid carriers which are identical in all
5.3 This test method can be used to determine particle size
respects.
distributions of catalysts and supports for materials specifica-
tions, manufacturing control, and research and development 9. Sampling and Sample Size
work.
9.1 Arepresentative test sample shall be obtained according
to Practice E105. The test portion shall be extracted from the
6. Interferences
test sample using a micro sample splitter according to
6.1 Air bubbles entrained in the circulating fluid will scatter MNL 32. Quartering shall not be used.
light and then be reported as particles. Circulating fluids, 9.2 Refer to the equipment manufacturer’s recommendation
typically, do not require degassing, but should be bubble-free to ensure that the amount of the test portion is acceptable to
achieve optimum light scattering conditions. A wide range of
on visual inspections.
6.2 Contaminants, such as non-aqueous so
...
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