ASTM D4926-15

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 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Nov-2015
• ICS: 71.040.30 - Chemical reagents
• Technical Committee: D32 - Catalysts
• Drafting Committee: D32.01 - Physical-Chemical Properties

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D4926 − 15
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 assuming that the X-ray powder diffraction peak occurring at
about 67 °2θ is attributable to gamma alumina. Gamma
1.1 This test method covers the determination of gamma
alumina is defined as a transition alumina formed after heating
alumina and related transition aluminas in catalysts and cata-
in the range from 500 to 550°C, and may include forms
lyst carriers containing silica and alumina by X-ray powder
described in the literature as eta, chi, and gamma aluminas.
diffraction, using the diffracted intensity of the peak occurring
Delta alumina has a diffraction peak in the same region, but is
at about 67 °2θ when copper Kα radiation is employed.
formed above 850°C, a temperature to which most catalysts of
1.2 The values stated in SI units are to be regarded as
this type are not heated. There are other possible components
standard. No other units of measurement are included in this
which may cause some interference, such as alpha-quartz and
standard.
zeolite Y, as well as aluminum-containing spinels formed at
1.3 This standard does not purport to address all of the
elevated temperatures. If the presence of interfering material is
safety concerns, if any, associated with its use. It is the
suspected,thediffractionpatternshouldbeexaminedingreater
responsibility of the user of this standard to establish appro-
detail. More significant interference may be caused by the
priate safety and health practices and determine the applica-
presenceoflargeamountsofheavymetalsorrareearths,which
bility of regulatory limitations prior to use.
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:
E691 Practice for Conducting an Interlaboratory Study to
5. Apparatus
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°,
3.1 A sample of catalyst or catalyst carrier is calcined and
respectively), goniometer speed of 0.5°/min or equivalent,
ground, and an X-ray powder diffraction pattern is obtained
chart speed of about 0.5 cm/min or equivalent, and scale or
under specified conditions over the approximate range from 52
gain factors to provide conveniently measurable peaks. Com-
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
reference sample, after appropriate adjustments are made for
NOTE 1—For diffractometers employing step scanning, convenient
corresponding conditions include a step size of 0.02° and a counting time
scale settings and peak half-widths.
of 2.4 s/step, which is equivalent to a scanning rate of 0.5°/min.
4. Significance and Use
5.2 Calcination Furnace.
4.1 This test method is for estimating the relative amount of
5.3 Grinding Equipment, suitable for preparing samples for
gamma alumina in calcined catalyst or catalyst carrier samples,
mounting in the sample holder.
1
This test method is under the jurisdiction of ASTM Committee D32 on 6. Procedure
Catalysts and is the direct responsibility of Subcommittee D32.01 on Physical-
Chemical Properties. 6.1 Calcine the catalyst or catalyst carrier sample for3hat
Current edition approved Dec. 1, 2015. Published January 2016. Originally
500°C.
approvedin1989.Lastpreviouseditionapprovedin2011asD4926–06(2011).DOI:
10.1520/D4926-15.
6.2 Grind the sample sufficiently (for example, 200 to 400
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
mesh) to enable it to be packed into a standard X-ray powder
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
diffractometer sample holder and mounted on the diffractome-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. ter.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D4926 − 15
6.3 Obtain diffraction patterns for three samples over the gamma alumina, and the sample does not contain la
...

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 − 06 (Reapproved 2011) D4926 − 15
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 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 and health practices and determine the applicability of regulatory
limitations prior to use.
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
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.
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 0.5
cm/min or equivalent, and scale or gain factors to provide conveniently measurable peaks. Computerized data acquisition
equipment may also be used.
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 April 1, 2011Dec. 1, 2015. Published April 2011January 2016. Originally approved in 1989. Last previous edition approved in 20062011 as
D4926D4926–06(2011).–06. DOI: 10.1520/D4926-06R11.10.1520/D4926-15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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

---------------------- Page: 1 ----------------------
D4926 − 15
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.
5.2 Calcination Furnace.
5.3 Grinding Equipment, suitable for preparing samples for mounting in the sample
...