ISO 20203:2005

INTERNATIONAL ISO
STANDARD 20203
First edition
2005-10-01

Carbonaceous materials used in the
production of aluminium — Calcined
coke — Determination of crystallite size
of calcined petroleum coke by X-ray
diffraction
Produits carbonés utilisés pour la production de l'aluminium — Coke
calciné — Détermination de la taille de la cristallite du coke calciné de
pétrole par diffraction aux rayons X




Reference number
ISO 20203:2005(E)
©
ISO 2005

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ISO 20203:2005(E)
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ISO 20203:2005(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
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International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 20203 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary
aluminium.
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ISO 20203:2005(E)
Introduction
[6]
This International Standard is based on ASTM D5187-91(2002) published by ASTM International, 100 Barr
Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
ASTM D5187-91(2002) was developed under the jurisdiction of ASTM Committee D02 on Petroleum Products
and Lubricants as the direct responsibility of Subcommittee D02.05.0D on Petroleum Coke Sampling and
Procedures, and was published in December 1991.
The crystallinity of petroleum coke, as reflected by the L value, is a general measure of quality affecting
c
suitability for end use and is a function of the heat treatment used.
The crystallite height is used to determine the extent of such heat treatment, for example, during calcination.
The value of the L determined is not affected by coke microporosity or the presence of foreign, non-
c
crystalline materials such as dedust oil.

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INTERNATIONAL STANDARD ISO 20203:2005(E)

Carbonaceous materials used in the production of aluminium —
Calcined coke — Determination of crystallite size of calcined
petroleum coke by X-ray diffraction
SAFETY PRECAUTIONS — This International 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.
1 Scope
This International Standard describes a test method for the determination of the mean crystallite height of a
representative, pulverized sample of calcined petroleum coke by interpretation of an X-ray diffraction pattern
produced through conventional X-ray scanning techniques.
It applies to carbonaceous materials used in the production of aluminium.
Calcined petroleum coke contains crystallites of different heights. This test method covers the determination of
the average height of all crystallites in the sample by empirical interpretation of the X-ray diffraction pattern.
The crystallite diameter (L ) is not determined by this test method.
a
2 Terms and definitions
For the purposes of this document, the following terms, abbreviated terms and definitions apply.
2.1
crystallites
stacks of graphitic carbon platelets located parallel to one another
2.2
L
C
mean or average height of crystallites in a sample
NOTE It is expressed as a linear dimension, in nanometres.
2.3
hkl(002)
Miller indices of the crystalline planes of graphite corresponding to a lattice spacing (d) of 0,335 nm
2.4
Θ
glancing angle produced when a parallel beam of uniform X-rays impinges upon a crystalline lattice and
measured by the X-ray goniometer
NOTE It is usually expressed in ° 2Θ .
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ISO 20203:2005(E)
3 Principle
A packed sample pulverized to less than 75 µm is subjected to a monochromatic X-ray beam and rotated to
produce a diffraction pattern under specific conditions. The location and shape of the peak with hkl (002) at
d = 0,335 nm is used to calculate L by manual interpretation of the peak or by computer simulation.
c
4 Apparatus
4.1 X-ray powder diffractometer, equipped with an X-ray source set for Cu-Kα radiation, a
monochromator or filter for restricting the wavelength range, a sample holder, a radiation detector, a signal
processor, and readout (chart or computer memory). The diffractometer shall be capable of rate scanning at
1°/min or incrementally step scanning at 0,2°/step.
4.2 Sample holders, as specified by the manufacturer of the diffractometer, that enable packing of a
pulverized sample of sufficient height to expose a level, smooth surface to the X-ray beam.
4.3 Briquetting press, capable of generating pressures up to 70 MPa.
4.4 Compressible aluminum caps, used as a support for producing a briquetted sample.
4.5 Silicon or quartz sample, of reference material quality suitable for calibrating the diffractometer.
NOTE These materials are usually available from national reference organizations e.g. the National Institute of
Standards and Technology in USA.
5 Reagents and materials
Use only reagents of recognized analytical grade and only distilled water or water of equivalent purity (see [1],
[2] and [3] in the Bibliography).
5.1 Acetone.
5.2 Polyethylene glycol, approximate molecular weight of 200.
5.3 Binding agent, prepare a solution of polyethylene glycol and acetone, so that the proportion of
polyethylene glycol in the solution, expressed as a mass fraction (w) by percentage of the total composition. is
15 %, by adding 15 g of polyethylene glycol to 85 g of acetone.
6 Sample preparation
6.1 General
[5]
For recommended practices for obtaining, handling and preparing coke samples, refer to ISO 6375 .
Reduce and divide the gross sample to obtain a laboratory analysis sample.
Divide, by riffling, a minimum of 100 g from the labo
...