ISO 17500:2006

INTERNATIONAL ISO
STANDARD 17500
First edition
2006-04-01
Aluminium oxide used for the production
of primary aluminium — Determination of
attrition index
Oxyde d'aluminium utilisé pour la production de l'aluminium primaire —
Détermination de l'index d'attrition

Reference number
©
ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Principle. 1
4 Apparatus. 1
5 Sample handling and preparation. 3
5.1 Reference alumina. 3
5.2 Test sample. 3
6 Procedure. 3
6.1 Flow calibration. 3
6.2 Attrition procedure for test sample and reference alumina . 6
6.3 Particle size distribution analysis . 6
7 Calculation and reporting of results . 6
8 Precision. 7
9 Quality control. 7
10 Test report. 7
Annex A (informative) Results of test programme . 8
Bibliography . 9

Foreword
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(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
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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 17500 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary
aluminium.
iv © ISO 2006 – All rights reserved

Introduction
This International Standard is based on Australian method, AS 2879.10-2003, Alumina — Determination of
attrition index.
The Attrition Index reference material ASCRM 025 was released in December 2003 by SAI Global, along with
a Technical Report on its preparation (TR 2.25-2003). These are available from SAI through their website:
http://www.standards.com.au/
INTERNATIONAL STANDARD ISO 17500:2006(E)

Aluminium oxide used for the production of primary
aluminium — Determination of attrition index
1 Scope
This International Standard specifies a procedure for the determination of the attrition index of smelter-grade
alumina.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 2926:2005, Aluminium oxide used for the production of primary aluminium — Particle size analysis for the
range 45 µm to 150 µm — Method using electroformed sieves
AS 2879.6-1995, Alumina — Determination of the mass distribution of particle sizes using electroformed
sieves
3 Principle
A test portion is attrited using a high velocity gas jet under controlled conditions using the attrition index
apparatus. Flow in the apparatus is calibrated to a reference alumina. The particle size distribution is
measured before and after attrition. The attrition index is the relative percentage decrease in the + 45 µm
fraction under specific test conditions.
4 Apparatus
4.1 Attrition index apparatus.
A typical assembled apparatus is shown in Figure 1 which consists of:
a) Column
Stainless steel, aluminium and glass columns of length 1 500 mm to 1 600 mm and inside diameter 25 mm
have been tested and found to be suitable. To minimize dust carryover, columns with larger-diameter upper
sections are also suitable. A column of reduced overall length (700 mm) and upper diameter 64 mm has also
been found to be suitable. In any case, modified columns shall maintain the 25 mm ID for a minimum of
200 mm from the orifice plate. Also, they shall be constructed with a smooth tapered transition between
sections, to ensure that alumina is not held up in the upper section of the column. Columns may also be
provided with a timed automated rapper to facilitate rapping the column [see 6.2 f)].
b) Orifice plate and assembly
1)
The orifice plate assembly holds and seals the orifice plate centrally to the base of the column. The orifice
plate has a circular aperture of (400 ± 15) µm diameter cut through a hard material. A typical orifice plate and
its correct orientation is shown in Figure 2.
Flow variations caused by minor dimensional variations between orifice plates are overcome by calibration
with a reference alumina.
c) Dust filter and assembly
The dust filter assembly holds and seals the dust filter to the top of the column. Ideally the assembly should
enclose the filter to allow subsequent flow measurement to the atmosphere, so that the flow can be monitored
to ensure that it is maintained for the test period.
NOTE A cellulose Soxhlet thimble, with an internal diameter of 43 mm and length of 123 mm, has been found to be a
suitable filter.
d) Flow measurement and control equipment
The flow measurement and control equipment shall include components to measure and control the airflow, to
within 0,1 l/min, at the operating flows (typically 5 l/min to 8 l/min).
4.2 Balance.
Analytical balance capable of weighing 100 g to the nearest 0,01 g.
4.3 Particle sizing apparatus.
Electroformed sieves and apparatus as specified in ISO 2926:2005. For an alternative sizing technique, see
Note to 6.3.
4.4 Sample splitter.
To provide representative portions, a rotary splitter is preferred.
4.5 Dried air or nitrogen supply.
A regulated system capable of supplying stable pressures, typically in the range 400 kPa to 800 kPa.
4.6 Sample containers.
Capable of being sealed and with a volume of between 60 ml and 125 ml.
4.7 Reference alumina.
With a certified attrition index value.
NOTE A suita
...