Solid mineral fuels -- Major and minor elements in coal ash and coke ash -- Wavelength dispersive x-ray fluorescence spectrometric method

This document sets out a wavelength dispersive X-ray fluorescence (XRF) procedure for the determination of silicon, aluminium, iron, calcium, magnesium, sodium, potassium, titanium, manganese, phosphorus and sulfur.

Combustibles minéraux solides -- Éléments en minorité et en majorité dans les cendres de houille et de coke -- Méthode spectrométrique par fluorescence aux rayons X à une longueur d'onde dispersive

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Status
Published
Publication Date
18-Oct-2018
Current Stage
6060 - International Standard published
Start Date
01-Sep-2018
Completion Date
19-Oct-2018
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INTERNATIONAL ISO
STANDARD 13605
First edition
2018-10
Solid mineral fuels — Major and
minor elements in coal ash and coke
ash — Wavelength dispersive x-ray
fluorescence spectrometric method
Combustibles minéraux solides — Éléments en minorité et en majorité
dans les cendres de houille et de coke — Méthode spectrométrique
par fluorescence aux rayons X à une longueur d'onde dispersive
Reference number
ISO 13605:2018(E)
ISO 2018
---------------------- Page: 1 ----------------------
ISO 13605:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
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Published in Switzerland
ii © ISO 2018 – All rights reserved
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ISO 13605:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Principle ........................................................................................................................................................................................................................ 2

5 Reagents ........................................................................................................................................................................................................................ 2

5.1 General ........................................................................................................................................................................................................... 2

5.2 Flux and heavy absorber ................................................................................................................................................................ 2

6 Apparatus ..................................................................................................................................................................................................................... 2

7 Sample ............................................................................................................................................................................................................................. 3

7.1 Coal and coke ash prepared in the laboratory ............................................................................................................. 3

7.2 Coal and coke ash .................................................................................................................................................................................. 4

8 Procedure..................................................................................................................................................................................................................... 4

8.1 Number of determinations ........................................................................................................................................................... 4

8.2 Test portion ................................................................................................................................................................................................ 4

8.3 Check test ..................................................................................................................................................................................................... 4

8.4 Calibration .................................................................................................................................................................................................. 4

8.5 Preparation of the fused discs ................................................................................................................................................... 4

8.5.1 General...................................................................................................................................................................................... 4

8.5.2 Disc storage .......................................................................................................................................................................... 5

8.5.3 Fused disc quality ........................................................................................................................................................... 5

8.6 XRF measurement ................................................................................................................................................................................ 5

8.6.1 Instrumental conditions ............................................................................................................................................ 5

8.6.2 Monitor measurements ........................................................................................................................................... ... 6

9 Calculation .................................................................................................................................................................................................................. 7

9.1 General ........................................................................................................................................................................................................... 7

9.2 Correction of instrumental drift .............................................................................................................................................. 7

9.3 Correction for dead time losses ................................................................................................................................................ 7

9.4 Matrix corrections ................................................................................................................................................................................ 7

10 Reporting results ................................................................................................................................................................................................. 8

11 Precision ....................................................................................................................................................................................................................... 8

12 Test report ................................................................................................................................................................................................................... 9

Annex A (normative) Acceptance of analytical results for laboratory method .....................................................10

Annex B (informative) Reagents suitable for the preparation of synthetic calibration standards ..12

Annex C (normative) Standard deviation of glass disc preparation .................................................................................13

Annex D (informative) Calculation of phosphorus using P O ..............................................................................................15

2 5

Bibliography .............................................................................................................................................................................................................................16

© ISO 2018 – All rights reserved iii
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ISO 13605:2018(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 non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee

SC 5, Methods of analysis.

This first edition of ISO 13605 cancels and replaces ISO/TS 13605:2012, which has been technically

revised.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2018 – All rights reserved
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INTERNATIONAL STANDARD ISO 13605:2018(E)
Solid mineral fuels — Major and minor elements in
coal ash and coke ash — Wavelength dispersive x-ray
fluorescence spectrometric method

WARNING — Use of this document can involve hazardous materials, operations and equipment.

This document does not purport to address all of the safety problems associated with its use.

It is the responsibility of the user of this document to establish appropriate safety and health

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

1 Scope

This document sets out a wavelength dispersive X-ray fluorescence (XRF) procedure for the

determination of silicon, aluminium, iron, calcium, magnesium, sodium, potassium, titanium,

manganese, phosphorus and sulfur.

The method is applicable to coal ashes, coke ashes and boiler ashes having components within the

concentration ranges specified in Table 1.
Table 1 — Ranges of application of the method
Concentration range
Oxide
SiO 5 to 100
Al O 5 to 80
2 3
Fe O 0,1 to 25
2 3
CaO 0,05 to 25
MgO 0,05 to 25
Na O 0,05 to 5
K O 0,05 to 5
TiO 0,05 to 5
Mn O 0,005 to 5
3 4
P O 0,01 to 5
2 5
SO 0,05 to 10

NOTE 1 Additional analytes can be included in the method, provided that appropriate validation using reference materials

is carried out.

NOTE 2 The precision statistics can be determined using suitable reference materials.

NOTE 3 The method described in this document has been tested for the following additional analytes: BaO (0,01 % to 1 %);

SrO (0,01 % to 1 %) and ZnO (0,005 % to 1 %).
For information relating to phosphorus calculations, refer to Annex D.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 1171, Solid mineral fuels — Determination of ash

ISO 1213-2, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and analysis

© ISO 2018 – All rights reserved 1
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ISO 13605:2018(E)

ISO 13909-4, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples

ISO 13909-6, Hard coal and coke — Mechanical sampling — Part 6: Coke — Preparation of test samples

ISO 18283, Hard coal and coke — Manual sampling
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1213-2 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Principle

The specimen on which X-ray fluorescence measurements are made is prepared by incorporating

the test portion of the sample, via fusion, into a borate glass disc using a casting or press-quenching

procedure. By using such a specimen, particle size effects are eliminated.

Calibration is carried out using pure chemicals and/or reference standards, and by making matrix

corrections for inter-element effects.

It is expected that laboratories using this document have experience in analysing coal ashes of certain

compositions and that they employ calibrations that cover these compositions.
5 Reagents
5.1 General

Unless otherwise specified, all reagents shall be of analytical grade and only distilled water or water of

equivalent purity shall be used.
5.2 Flux and heavy absorber

Borate fluxes of differing compositions have been found suitable for preparing glass discs from coal/coke

ash samples. These fluxes are based on mixtures of one or more of the following: lithium tetraborate,

lithium metaborate and lanthanum oxide. Flux may be purchased commercially or prepared by fusion

of a mixture of individual reagents.

NOTE The levels of contamination in the flux should be checked. Because levels of contamination may vary

from batch to batch, the same batch of flux should be used for all specimens (synthetic standards, external

standards and unknowns). When using a fresh batch of flux, reference material specimens should be prepared to

determine whether adjustments to the calibration are required.
6 Apparatus

All apparatus shall be constructed from materials that are thermally stable and chemically inert under

the conditions of the procedure.
2 © ISO 2018 – All rights reserved
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ISO 13605:2018(E)
6.1 Crucible, made from a non-wetting platinum alloy.

The crucible shall have sufficient capacity to hold the flux and sample required for fusion. Normally,

15 ml crucibles are adequate for discs of 32 mm in diameter, and 25 ml crucibles for discs of 40 mm in

diameter.
NOTE Either platinum/gold or platinum/gold/rhodium alloys are suitable.

Because the crucible and lid (if used) are to be used for fusion work, the normal precautions associated

with the care of hot platinum ware should be observed. It is necessary, therefore, to have suitable tongs

and a surface on which to rest the crucible. The hot crucible can be rested on a refractory surface,

which shall be kept very clean.

Although the crucible is fabricated from an alloy that is not wetted by the glass, for the greatest

precision, the crucible should be cleaned between each fusion. The use of citric acid (mass concentration

of 20 %), dilute hydrochloric acid (volume fraction of 10 % to 50 %) or dilute chlorine-free nitric acid

(volume fraction of 10 %) have proven to be suitable for crucible cleaning. The use of an ultrasonic bath

will accelerate this process. An alternative method of cleaning is to fuse several grams of flux in the

crucible, moving the melt around so as to clean the entire inner surface. The molten flux is poured from

the crucible. If a droplet adheres to the crucible, this can easily be flaked off when the crucible is cold.

6.2 Mould, made from non-wetting material. For example, platinum alloy is commonly used for casting

discs, and aluminium or graphite is suitable for press quenching.

In the casting technique, the bottom of the disc is the analytical surface. The mould should therefore

be flat and sufficiently thick that it is not easily deformed. Casting moulds should be checked regularly

for flatness and should be polished regularly, to ensure that the disc releases from the mould. Platens

for press-quenching are constructed so that the depth gradually increases from the perimeter to the

centre. The analytical surface for press-quenched discs is the surface which contacts the plunger head.

Care should be taken not to choose the platen side for intensity measurements.
6.3 Crucible tongs, platinum-tipped or stainless steel or titanium.

NOTE Stainless steel or titanium tongs are a suitable alternative to platinum-tipped tongs.

6.4 Desiccator, containing freshly regenerated, self-indicating silica gel.
6.5 Sample holders, used for specimen presentation.

6.6 X-ray fluorescence spectrometer, any conventional wavelength dispersive (sequential,

simultaneous, or combination simultaneous/sequential) vacuum path X-ray fluorescence spectrometer

may be used, provided that it conforms to precision requirements at the 0,1 % (10 counts) precision level.

7 Sample
7.1 Coal and coke ash prepared in the laboratory

The coal or coke sample shall be the analysis sample, prepared to a nominal top size of 212 µm. Sample

preparation shall be in accordance with ISO 13909-4 for coal samples or ISO 13909-6 for coke samples

or ISO 18283.
The sample shall then be ashed using the procedure specified in ISO 1171.
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ISO 13605:2018(E)
7.2 Coal and coke ash

Laboratory-prepared ashes for XRF analysis should be received at the laboratory, freshly prepared If

not freshly prepared coal or coke ash, reheat at 815 °C for 15 min and cool in a desiccator immediately

prior to weighing for analysis.

Boiler ash received at the laboratory should be ground to a nominal top size of 63 µm and dried at

105 °C for 1 h, then stored in a desiccator over freshly regenerated, self-indicating silica gel.

8 Procedure
8.1 Number of determinations

Discs shall be prepared and analysed as single determinations and a reference material shall be

prepared and analysed at the beginning and end of each batch of samples containing a maximum of

25 samples.
8.2 Test portion

The mass of the test portion shall be appropriate for the mould size and sample flux ratio chosen.

NOTE 1 Typically, sample-to-flux ratios are in the range 1:5 to 1:10.

NOTE 2 Typical total mass (sample plus flux) is 4 g for a 32 mm diameter and 7,5 g for a 40 mm diameter mould.

8.3 Check test

At least one reference material of similar composition to the samples being analysed shall be included

with each batch of test samples and shall be analysed in parallel with, and under the same conditions

as, the test samples. The results for the batch of samples shall be rejected if the results for the reference

material fail to meet the acceptance criteria detailed in Annex A.
8.4 Calibration

Calibration shall be effected using either reference materials, synthetic standards or mixtures of

reference materials and synthetic standards. Reference materials shall be pre-treated in accordance

with the instructions contained on
...

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