ASTM D4926-20
(Test Method)Standard Test Method for Gamma Alumina Content in Catalysts and Catalyst Carriers Containing Silica and Alumina by X-ray Powder Diffraction
Standard Test Method for Gamma Alumina Content in Catalysts and Catalyst Carriers Containing Silica and Alumina by X-ray Powder Diffraction
SIGNIFICANCE AND USE
4.1 This test method is for estimating the relative amount of gamma alumina in calcined catalyst or catalyst carrier samples, assuming that the X-ray powder diffraction peak occurring at about 67 °2θ is attributable to gamma alumina. Gamma alumina is defined as a transition alumina formed after heating in the range from 500 to 550 °C, and may include forms described in the literature as eta, chi, and gamma aluminas. Delta alumina has a diffraction peak in the same region, but is formed above 850 °C, a temperature to which most catalysts of this type are not heated. There are other possible components which may cause some interference, such as alpha-quartz and zeolite Y, as well as aluminum-containing spinels formed at elevated temperatures. If the presence of interfering material is suspected, the diffraction pattern should be examined in greater detail. More significant interference may be caused by the presence of large amounts of heavy metals or rare earths, which exhibit strong X-ray absorption and scattering. Comparisons between similar materials, therefore, may be more appropriate than those between widely varying materials.
SCOPE
1.1 This test method covers the determination of gamma alumina and related transition aluminas in catalysts and catalyst carriers containing silica and alumina by X-ray powder diffraction, using the diffracted intensity of the peak occurring at about 67 °2θ when copper Kα radiation is employed.
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4926 − 20
Standard Test Method for
Gamma Alumina Content in Catalysts and Catalyst Carriers
1
Containing Silica and Alumina by X-ray Powder Diffraction
This standard is issued under the fixed designation D4926; 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 reference sample, after appropriate adjustments are made for
scale settings and peak half-widths.
1.1 This test method covers the determination of gamma
alumina and related transition aluminas in catalysts and cata-
4. Significance and Use
lyst carriers containing silica and alumina by X-ray powder
4.1 This test method is for estimating the relative amount of
diffraction, using the diffracted intensity of the peak occurring
gamma alumina in calcined catalyst or catalyst carrier samples,
at about 67 °2θ when copper Kα radiation is employed.
assuming that the X-ray powder diffraction peak occurring at
1.2 Units—The values stated in SI units are to be regarded
about 67 °2θ is attributable to gamma alumina. Gamma
as standard. No other units of measurement are included in this
alumina is defined as a transition alumina formed after heating
standard.
in the range from 500 to 550 °C, and may include forms
1.3 This standard does not purport to address all of the
described in the literature as eta, chi, and gamma aluminas.
safety concerns, if any, associated with its use. It is the
Delta alumina has a diffraction peak in the same region, but is
responsibility of the user of this standard to establish appro-
formed above 850 °C, a temperature to which most catalysts of
priate safety, health, and environmental practices and deter-
this type are not heated. There are other possible components
mine the applicability of regulatory limitations prior to use.
which may cause some interference, such as alpha-quartz and
1.4 This international standard was developed in accor-
zeolite Y, as well as aluminum-containing spinels formed at
dance with internationally recognized principles on standard-
elevated temperatures. If the presence of interfering material is
ization established in the Decision on Principles for the
suspected,thediffractionpatternshouldbeexaminedingreater
Development of International Standards, Guides and Recom-
detail. More significant interference may be caused by the
mendations issued by the World Trade Organization Technical
presenceoflargeamountsofheavymetalsorrareearths,which
Barriers to Trade (TBT) Committee.
exhibit strong X-ray absorption and scattering. Comparisons
between similar materials, therefore, may be more appropriate
2. Referenced Documents
than those between widely varying materials.
2
2.1 ASTM Standards:
5. Apparatus
E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
5.1 X-ray Powder Diffractometer Unit, with standard
sample mount, Cu Kα radiation, monochromator, wide diver-
3. Summary of Test Method
gence and receiving slits (for example, 3° and 0.15°,
respectively), goniometer speed of 0.5°/min or equivalent,
3.1 A sample of catalyst or catalyst carrier is calcined and
ground, and an X-ray powder diffraction pattern is obtained chart speed of about 0.5 cm⁄min or equivalent, and scale or
gain factors to provide conveniently measurable peaks. Com-
under specified conditions over the approximate range from 52
to 76 °2θ. The diffracted intensity above background for the puterized data acquisition equipment may also be used.
peak occurring at about 67 °2θ is compared to that of a
NOTE 1—For diffractometers employing step scanning, convenient
corresponding conditions include a step size of 0.02° and a counting time
of 2.4 s ⁄step, which is equivalent to a scanning rate of 0.5°/min.
1
This test method is under the jurisdiction of ASTM Committee D32 on
5.2 Calcination Furnace.
Catalysts and is the direct responsibility of Subcommittee D32.01 on Physical-
Chemical Properties.
5.3 Grinding Equipment, suitable for preparing samples for
Current edition approved Oct. 1, 2020. Published October 2020. Originally
mounting in the sample holder.
approved in 1989. Last previous edition approved in 2015 as D4926 – 15. DOI:
10.1520/D4926-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6. Procedure
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1 Calcine the catalyst or catalyst carrier sample for 3 h at
Standards volume information, refer to the standard’s Document S
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D4926 − 15 D4926 − 20
Standard Test Method for
Gamma Alumina Content in Catalysts and Catalyst Carriers
1
Containing Silica and Alumina by X-ray Powder Diffraction
This standard is issued under the fixed designation D4926; 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
1.1 This test method covers the determination of gamma alumina and related transition aluminas in catalysts and catalyst carriers
containing silica and alumina by X-ray powder diffraction, using the diffracted intensity of the peak occurring at about 67 °2θ when
copper Kα radiation is employed.
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
1.3 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Summary of Test Method
3.1 A sample of catalyst or catalyst carrier is calcined and ground, and an X-ray powder diffraction pattern is obtained under
specified conditions over the approximate range from 52 to 76 °2θ. The diffracted intensity above background for the peak
occurring at about 67 °2θ is compared to that of a reference sample, after appropriate adjustments are made for scale settings and
peak half-widths.
4. Significance and Use
4.1 This test method is for estimating the relative amount of gamma alumina in calcined catalyst or catalyst carrier samples,
assuming that the X-ray powder diffraction peak occurring at about 67 °2θ is attributable to gamma alumina. Gamma alumina is
1
This test method is under the jurisdiction of ASTM Committee D32 on Catalysts and is the direct responsibility of Subcommittee D32.01 on Physical-Chemical
Properties.
Current edition approved Dec. 1, 2015Oct. 1, 2020. Published January 2016October 2020. Originally approved in 1989. Last previous edition approved in 20112015 as
D4926–06(2011).D4926 – 15. DOI: 10.1520/D4926-15.10.1520/D4926-20.
2
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
1
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D4926 − 20
defined as a transition alumina formed after heating in the range from 500 to 550°C,550 °C, and may include forms described in
the literature as eta, chi, and gamma aluminas. Delta alumina has a diffraction peak in the same region, but is formed above
850°C,850 °C, a temperature to which most catalysts of this type are not heated. There are other possible components which may
cause some interference, such as alpha-quartz and zeolite Y, as well as aluminum-containing spinels formed at elevated
temperatures. If the presence of interfering material is suspected, the diffraction pattern should be examined in greater detail. More
significant interference may be caused by the presence of large amounts of heavy metals or rare earths, which exhibit strong X-ray
absorption and scattering. Comparisons between similar materials, therefore, may be more appropriate than those between widely
varying materials.
5. Apparatus
5.1 X-ray Powder Diffractometer Unit, with standard sample mount, Cu Kα radiation, monochromator, wide divergence and
receiving slits (for example, 3° and 0.15°, respectively), goniometer speed of 0.5°/min or equivalent, chart speed of about
0.50.5 cm cm/min ⁄min or equivalent, and scale or gain factors to provide conveniently measurable peaks. Comp
...
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