ISO 23201:2015

INTERNATIONAL ISO
STANDARD 23201
First edition
2015-11-15
Aluminium oxide primarily used
for production of aluminium —
Determination of trace elements
— Wavelength dispersive X-ray
fluorescence spectrometric method
Oxyde d’aluminium utilisé pour la production d’aluminium —
Détermination d’éléments traces — Spectrométrie de fluorescence des
rayons X par dispersion en longueur d’onde
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Principle . 2
4 Reagents and materials . 2
5 Apparatus . 3
6 Sampling and samples . 5
7 Procedure. 5
7.1 General . 5
7.2 Preparation of calibration specimens . 6
7.2.1 Determination of loss of mass on fusion of flux and flux correction . 6
7.2.2 Preparation of intermediate calibration glass (ICG) . 6
7.2.3 Preparation of the synthetic calibration disk (SCD) . 7
7.2.4 Preparation of the blank calibration discs . 9
7.3 Preparation of the sample discs . 9
7.4 X-ray fluorescence measurement .10
7.4.1 General instrumental conditions .10
7.4.2 Guidelines for instrument optimization .11
7.4.3 Sample loading .11
7.4.4 Monitor disc: correction for instrumental drift .11
7.4.5 Measurements for calibration .12
7.4.6 Measurement of test discs .13
8 Calculations.13
8.1 Calculation of net intensity .13
8.2 Comparison of duplicate measurements for the Al O blanks and Synthetic
2 3
Calibration Discs (SCDs) .14
8.2.1 SCDs criteria for the acceptability of duplicate measurements .14
8.2.2 Al O blanks criteria for the acceptability of duplicate measurement .14
2 3
8.3 Drift correction of measured intensities.15
8.4 Calculation of the calibration parameters .15
9 Consistency checks and reporting results .16
10 Precision .16
11 Accuracy .17
12 Quality assurance and control.17
13 Test report .17
Annex A (informative) Contamination issues and care of platinum ware .19
Annex B (normative) Example of instrument optimization .21
Annex C (informative) Calculation of reagent masses for different sample/flux
combinations and synthetic calibration discs when omitting some elements .25
Annex D (informative) Preparation of monitor disc .27
Annex E (informative) Interlaboratory test program analysis of NIST 699 and ASCRM 27
smelter grade alumina, certified reference materials .29
Annex F (informative) Comments on flux purity .31
Bibliography .32
Foreword
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The committee responsible for this document is ISO/TC 226, Materials for the production of primary
aluminium.
iv © ISO 2015 – All rights reserved

Introduction
This International Standard is based on Australian Standard AS 2879.7–1997, Alumina — Determination
of trace elements — Wavelength dispersive X-ray fluorescence spectrometric method, developed by the
Standards Australia Committee on Alumina and Materials used in Aluminium Production to provide an
XRF method for the analysis of alumina.
The objective of this International Standard is to provide those responsible for the analysis of smelting-
grade alumina with a standardized, validated procedure that will ensure the integrity of the analysis.
INTERNATIONAL STANDARD ISO 23201:2015(E)
Aluminium oxide primarily used for production of
aluminium — Determination of trace elements —
Wavelength dispersive X-ray fluorescence spectrometric
method
1 Scope
This International Standard sets out a wavelength dispersive X-ray fluorescence spectrometric method
for the analysis of aluminium oxide for trace amounts of any or all of the following elements: sodium,
silicon, iron, calcium, titanium, phosphorus, vanadium, zinc, manganese, gallium, potassium, copper,
chromium and nickel. These elements are expressed as the oxides Na O, SiO , Fe O , CaO, TiO , P O ,
2 2 2 3 2 2 5
V O , ZnO, MnO, Ga O , K O, CuO, Cr O and NiO on an un-dried sample basis.
2 5 2 3 2 2 3,
The method is applicable to smelting-grade aluminium oxide. The concentration range covered for each
of the components is given in Table 1.
Table 1 — Applicable concentration range
Concentration range
Component
%
Na O 0,10 to 1,00
SiO 0,003 to 0,05
Fe O 0,003 to 0,05
2 3
CaO 0,003 to 0,10
TiO 0,000 5 to 0,010
P O 0,000 5 to 0,050
2 5
V O 0,000 5 to 0,010
2 5
ZnO 0,000 5 to 0,010
MnO 0,000 5 to 0,010
Ga O 0,000 5 to 0,020
2 3
K2O 0,000 5 to 0,010
CuO 0,000 5 to 0,010
Cr O 0,000 5 to 0,010
2 3
NiO 0,000 5 to 0,010
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
AS 2563, Wavelength dispersive X-ray fluorescence spectrometers — Determination of precision
AS 2706, Numeric values — Rounding and interpretation of limiting values
AS 4538.1-1999 (R2013), Guide to the sampling of alumina — Sampling procedures
AS 4538.2-2000 (R2013), Guide to the sampling of alumina — Preparation of samples
3 Principle
A portion of the aluminium oxide test sample is incorporated, via fusion, into a borate glass disc using a
casting technique. X-ray fluorescence measurements are made on this disc.
Calibration is carried out using synthetic standards prepared from pure chemicals using a two-point
regression. Matrix corrections may be employed but, because of the low levels at which the analytes are
present in the Al O matrix, will have negligible effect within the scope of the method.
2 3
Intensity measurements are corrected for spectrometer drift.
A certified reference material, (see Annex E) is used to verify the calibration.
4 Reagents and materials
4.1 Flux, mixture of 12 parts lithium tetraborate to 22 parts lithium metaborate, pre-fused.
This flux is available commercially. Flux will absorb atmospheric moisture when exposed to air.
Minimize water uptake by storing flux in an airtight container.
See Annex F for comments on flux purity.
4.2 Aluminium oxide (Al O ), high purity, nominally 99,999 % Al O .
2 3 2 3
Prepared by heating to 1
...