Solid recovered fuels - Determination of elemental composition by X-ray fluorescence (ISO 22940:2021)

This document specifies the procedure for a determination of major and minor element concentrations in solid recovered fuel material by energy dispersive X-ray fluorescence (EDXRF) spectrometry or wavelength dispersive X-ray fluorescence (WDXRF) spectrometry using a calibration with solid recovered fuel reference materials or solid recovered fuel samples with known content. A semiquantitative determination may be carried out using matrix independent standards.
X-ray fluorescence spectrometry can be used as a fast method for a qualitative overview of elements and impurities and after suitable calibration it is very useful for determining major elements or even minor elements (except Hg) in order to quickly identify increased concentrations of minor elements in solid recovered fuels (e.g. during SRF-production).
This document is applicable for the following elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Mo, Cd, Sb, Tl and Pb. Concentrations from approximately 0,000 1 % and above can be determined depending on the element, the calibration materials used and the instrument used.

Feste Sekundärbrennstoffe - Bestimmung der Elementzusammensetzung durch Röntgenfluoreszenz (ISO 22940:2021)

Dieses Dokument legt ein Verfahren zur Bestimmung der Konzentrationen von Haupt- und Nebenelementen in Material von festen Sekundärbrennstoffen durch energiedispersive Röntgenfluoreszenz-Spektrometrie oder wellenlängendispersive Röntgenfluoreszenz-Spektrometrie unter Anwendung einer Kalibrierung mit Referenzmaterialien für feste Sekundärbrennstoffe oder Proben von festen Sekundärbrennstoffen mit bekanntem Gehalt fest. Eine semiquantitative Bestimmung kann unter Verwendung matrixunabhängiger Standards durchgeführt werden.
Dieses Dokument ist anwendbar auf die folgenden Elemente: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Mo, Cd, Sb, Tl und Pb. In Abhängigkeit von dem Element, den verwendeten Kalibriermaterialien und dem verwendeten Gerät können Konzentrationsniveaus zwischen etwa 0,000 1 % und 100 % bestimmt werden.
ANMERKUNG Die Röntgenfluoreszenz-Spektrometrie kann als ein schnelles Verfahren für einen qualitativen Überblick über Elemente und Verunreinigungen angewendet werden und ist nach einer geeigneten Kalibrierung sehr nützlich für die Bestimmung von Hauptelementen oder sogar Nebenelementen (außer Hg), um schnell erhöhte Konzentrationen von Nebenelementen in festen Sekundärbrennstoffen (SRF, en: solid recovered fuels) zu identifizieren, zum Beispiel während der SRF-Produktion.

Combustibles solides de recupération - Détermination de la composition élémentaire par fluorescence de rayons X (ISO 22940:2021)

Trdna alternativna goriva - Določevanje elementne sestave z rentgensko fluorescenco (ISO 22940:2021)

General Information

Status
Published
Public Enquiry End Date
30-Nov-2020
Publication Date
04-Oct-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
22-Sep-2021
Due Date
27-Nov-2021
Completion Date
05-Oct-2021

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SLOVENSKI STANDARD
SIST EN ISO 22940:2021
01-november-2021
Trdna alternativna goriva - Določevanje elementne sestave z rentgensko
fluorescenco (ISO 22940:2021)

Solid recovered fuels - Determination of elemental composition by X-ray fluorescence

(ISO 22940:2021)
Feste Sekundärbrennstoffe - Bestimmung der Elementzusammensetzung durch
Röntgenfluoreszenz (ISO 22940:2021)

Combustibles solides de recupération - Détermination de la composition élémentaire par

fluorescence de rayons X (ISO 22940:2021)
Ta slovenski standard je istoveten z: EN ISO 22940:2021
ICS:
75.160.10 Trda goriva Solid fuels
SIST EN ISO 22940:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 22940:2021
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SIST EN ISO 22940:2021
EN ISO 22940
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2021
EUROPÄISCHE NORM
ICS 75.160.10
English Version
Solid recovered fuels - Determination of elemental
composition by X-ray fluorescence (ISO 22940:2021)

Combustibles solides de recupération - Détermination Feste Sekundärbrennstoffe - Bestimmung der

de la composition élémentaire par fluorescence de Elementzusammensetzung durch Röntgenfluoreszenz

rayons X (ISO 22940:2021) (ISO 22940:2021)
This European Standard was approved by CEN on 16 August 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22940:2021 E

worldwide for CEN national Members.
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SIST EN ISO 22940:2021
EN ISO 22940:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 22940:2021
EN ISO 22940:2021 (E)
European foreword

This document (EN ISO 22940:2021) has been prepared by Technical Committee ISO/TC 300 "Solid

recovered materials, including solid recovered fuels" in collaboration with Technical Committee

CEN/TC 343 “Solid Recovered Fuels” the secretariat of which is held by SFS.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by March 2022, and conflicting national standards shall

be withdrawn at the latest by March 2022.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

Any feedback and questions on this document should be directed to the users’ national standards

body/national committee. A complete listing of these bodies can be found on the CEN websites.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,

Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of

North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the

United Kingdom.
Endorsement notice

The text of ISO 22940:2021 has been approved by CEN as EN ISO 22940:2021 without any modification.

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SIST EN ISO 22940:2021
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SIST EN ISO 22940:2021
INTERNATIONAL ISO
STANDARD 22940
First edition
2021-08
Solid recovered fuels — Determination
of elemental composition by X-ray
fluorescence
Combustibles solides de récupération — Détermination de la
composition élémentaire par fluorescence de rayons X
Reference number
ISO 22940:2021(E)
ISO 2021
---------------------- Page: 7 ----------------------
SIST EN ISO 22940:2021
ISO 22940:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 8 ----------------------
SIST EN ISO 22940:2021
ISO 22940:2021(E)
Contents Page

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

Introduction ..................................................................................................................................................................................................................................v

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 3

4.1 Symbols ......................................................................................................................................................................................................... 3

4.2 Abbreviated terms ............................................................................................................................................................................... 4

5 Safety remarks ........................................................................................................................................................................................................ 4

6 Principle ........................................................................................................................................................................................................................ 4

7 Apparatus ..................................................................................................................................................................................................................... 4

8 Interferences and sources of error .................................................................................................................................................... 5

9 Sample preparation ........................................................................................................................................................................................... 5

9.1 Preparation principles ...................................................................................................................................................................... 5

9.2 Drying of general analysis sample material ................................................................................................................... 5

9.3 Preparation of pressed pellet ..................................................................................................................................................... 6

10 Procedure..................................................................................................................................................................................................................... 6

10.1 Analytical measurement conditions ..................................................................................................................................... 6

10.1.1 Wavelength-dispersive instruments ............................................................................................................... 6

10.1.2 Energy-dispersive instruments ........................................................................................................................... 7

10.1.3 Intensities and background corrections ...................................................................................................... 7

10.2 Calibration .................................................................................................................................................................................................. 8

10.2.1 General...................................................................................................................................................................................... 8

10.2.2 General calibration procedure ............................................................................................................................. 8

10.2.3 Calibration procedure using the pressed pellet method (recommended method) 9

10.3 Procedures for correcting matrix effects .......................................................................................................................10

10.3.1 General...................................................................................................................................................................................10

10.3.2 Internal standard correction using Compton (incoherent) scattering method .....10

10.3.3 Fundamental parameter approach ...............................................................................................................10

10.3.4 Fundamental or theoretical influence coefficient method .......................................................10

10.3.5 Empirical alpha correction .................. .................................................................................................................11

10.4 Analysis of the samples .................................................................................................................................................................11

11 Quality control .....................................................................................................................................................................................................12

11.1 Drift correction procedure .........................................................................................................................................................12

11.2 Reference materials and quality control samples .................................................................................................12

12 Calculation of the result .............................................................................................................................................................................12

13 Performance characteristics .................................................................................................................................................................13

14 Test report ................................................................................................................................................................................................................13

Annex A (informative) Publicly available solid recovered fuel reference materials .......................................14

Annex B (informative) Validation .........................................................................................................................................................................15

Bibliography .............................................................................................................................................................................................................................38

© ISO 2021 – All rights reserved iii
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SIST EN ISO 22940:2021
ISO 22940:2021(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 300, Solid recovered materials, including

solid recovered fuels, in collaboration with the European Committee for Standardization (CEN)

Technical Committee CEN/TC 343, Solid Recovered Fuels, in accordance with the Agreement on technical

cooperation between ISO and CEN (Vienna Agreement).

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 2021 – All rights reserved
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SIST EN ISO 22940:2021
ISO 22940:2021(E)
Introduction

X-ray fluorescence spectrometry can be used as a fast method for a qualitative overview of ash forming

elements and impurities. When calibration is based on reference materials or on matrix-matched

homogeneous solid recovered fuel samples with known content, X-ray fluorescence spectrometry can

be used for a quantitative analysis of the total content of the specified elements within different solid

recovered fuels.

The quality of the results obtained depends very closely on the type of instrument used, e.g. bench

top or high performance, energy-dispersive or wavelength-dispersive instruments. When selecting a

specific instrument, several factors need to be considered, such as the matrices to be analysed, elements

to be determined, detection limits required and the measuring time.

Due to the wide range of matrix compositions and the lack of suitable reference materials in the case

of solid recovered fuels from various origin, it is generally difficult to set up a calibration with matrix-

matched reference materials. Therefore, it is important to use several homogenized solid recovered fuel

samples with properties that sufficiently match the matrices of interest and whose content has been

derived by independent measurement techniques, for example total digestion of solid recovered fuels

and characterization of major and minor elements by measurement of digestion solutions with ICP-MS

or ICP-OES, or by other techniques such as elemental analysis using combustion technology on sulfur or

by combustion and ion chromatographic determination for chlorine.
This document describes two different procedures:

1) Quantitative analytical procedure for major elements of solid recovered fuels. The calibration is

based on different reference materials and solid recovered fuel samples with known content.

The elements described as major elements of solid recovered fuels are in fact major elements of the

fuel ashes more than of the fuels. The determination of these elements can be helpful to predict the

melting behaviour and slagging of the ashes. Moreover, contamination of fuel with sand or soil is

indicated by high values of several elements.

2) Total element characterization at a semiquantitative level for major and minor elements of solid

recovered fuels. The calibration is based on matrix-independent calibration curves, previously set

up by the manufacturer.

In general, the sensitivity of X-ray fluorescence is not sufficient for a determination of the content of

minor elements (trace metals) in solid recovered fuels. However, it is possible to use determination

of minor elements after calibration with solid recovered fuel samples with known content or at a

semiquantitative level based on matrix-independent calibration curves to collect data for higher

sample numbers, taking into account lower achievable precision. Therefore, it may be used to

reveal excessive contents of minor elements in solid recovered fuels.
© ISO 2021 – All rights reserved v
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SIST EN ISO 22940:2021
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SIST EN ISO 22940:2021
INTERNATIONAL STANDARD ISO 22940:2021(E)
Solid recovered fuels — Determination of elemental
composition by X-ray fluorescence
1 Scope

This document specifies the procedure for a determination of major and minor element concentrations

in solid recovered fuel material by energy-dispersive X-ray fluorescence (EDXRF) spectrometry

or wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry using a calibration with

solid recovered fuel reference materials or solid recovered fuel samples with known content. A

semiquantitative determination can be carried out using matrix independent standards.

This document is applicable to the following elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co,

Ni, Cu, Zn, As, Br, Mo, Cd, Sb, Sn, Tl and Pb. Concentration levels between approximately 0,000 1 % and

100 % can be determined depending on the element, the calibration materials used and the instrument

used.

NOTE X-ray fluorescence spectrometry can be used as a fast method for a qualitative overview of elements

and impurities and after suitable calibration it is very useful for determining major elements or even minor

elements (except Hg) in order to quickly identify increased concentrations of minor elements in solid recovered

fuels (SRF), for example during SRF-production.
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 21637, Solid recovered fuels — Vocabulary
ISO 21646, Solid recovered fuels — Sample preparation

ISO 21660-3, Solid recovered fuels — Determination of moisture content using the oven dry method —

Part 3: Moisture in general analysis sample
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 21637 and the following 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/
3.1
absorption edge
abrupt change in mass absorption coefficient at a specific wavelength or energy
3.2
absorption

loss of intensity of X-rays due to isotropic and homogenous material, as described by the Beer-Lambert

law
1) Under preparation. Stage at the time of publication: ISO/DIS 21646:2021.
© ISO 2021 – All rights reserved 1
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SIST EN ISO 22940:2021
ISO 22940:2021(E)
3.3
analytical line

specific characteristic X-ray spectral line of the atom or ion of the analyte used for determination of the

analyte content
3.4
continuous radiation (Bremsstrahlung)

electromagnetic radiation produced by the acceleration of a charged particle, such as an electron, when

deflected by another charged particle, such as an atomic nucleus
3.5
Compton line

spectral line due to incoherent scattering (Compton effect), occurring when the incident X-ray photon

strikes an atom without promoting fluorescence

Note 1 to entry: Energy is lost in the collision and, therefore, the resulting scattered X-ray photon is of lower

energy than the incident X-ray photon.
3.6
drift correction monitors
physically stable samples used to correct for instrumental drift
3.7
emitted radiation
emitted sample X-rays

radiation emitted by sample consisting of X-ray fluorescence radiation (3.13) and scattered primary

X-rays (3.11)
3.8
mass absorption coefficient

constant describing the fractional decrease in the intensity of a beam of X-radiation as it passes through

an absorbing medium
Note 1 to entry: It is expressed in cm /g.

Note 2 to entry: The mass absorption coefficient is a function of the wavelength of the absorbed radiation and the

atomic number of the absorbing element.
3.9
powder sample
analyte sample submitted as a powder for direct measurement in the sample cup
3.10
pressed pellet
analyte sample prepared by pressing milled material into a disk
3.11
primary X-rays
X-rays by which the sample is radiated
3.12
quality control sample

stable sample with known contents, for example (certified) reference material (CRM) or homogenized

solid recovered fuel samples from known origin whose contents have been derived by independent

analysis used to monitor instrument and calibration performance
3.13
X-ray fluorescence radiation

emission of characteristic X-rays from a sample that has been bombarded by high-energy X-rays or

gamma rays
2 © ISO 2021 – All rights reserved
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SIST EN ISO 22940:2021
ISO 22940:2021(E)
4 Symbols and abbreviated terms
4.1 Symbols
Al aluminium
As arsenic
Br bromine
Ca calcium
Cd cadmium
Cl chlorine
Co cobalt
Cr chromium
Cu copper
Fe iron
K potassium
Mg magnesium
Mn manganese
Mo molybdenum
Na sodium
Ni nickel
P phosphorus
Pb lead
S sulfur
Sb antimony
Si silicon
Sn tin
Ti titanium
Tl thallium
V vanadium
Zn zinc
© ISO 2021 – All rights reserved 3
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SIST EN ISO 22940:2021
ISO 22940:2021(E)
4.2 Abbreviated terms
EDXRF energy-dispersive x-ray fluorescence
MCA multi-channel analyser
WDXRF wavelength-dispersive x-ray fluorescence
5 Safety remarks

The organization shall be aware of applicable legal requirements relating to the X-ray fluorescence

spectrometer.

The person responsible for managing or supervising the operation of X-ray equipment shall provide

evidence of their knowledge of national regulations relating to radiation protection.

6 Principle

After a suitable preparation, the sample is introduced into an XRF-spectrometer and excited by primary

X-rays. The intensities of the secondary fluorescent energy lines specific for each element are measured

and the elemental composition of the sample is determined by reference to previously established

calibration graphs or equations and applying corrections for inter-element effects. The calibration

equations and inter-element corrections are established using pure reagents and/or series of internal

or reference materials, provided that they meet all the requirements of the relevant preparation

technique.
7 Apparatus

7.1 X-ray fluorescence spectrometer, which shall be able to analyse the elements according to the

scope of this document. The following types of X-ray fluorescence spectrometers are applicable:

— EDXRF spectrometer that achieves the dispersion of the emitted X-ray fluorescence radiation by an

energy-dispersive detector;

— WDXRF spectrometer that achieves the dispersion of the emitted X-ray fluorescence radiation by

diffraction by a crystal or a synthetic multilayer.
The spectrometer consists of the following components:
— primary X-ray source, an X-ray tube with a high-voltage generator;
— sample holder;
— detector unit including electronic equipment;

— source modifiers to modify the shape or intensity of the source spectrum or the beam shape (e.g.

source filters, secondary targets, polarizing targets, collimators, focusing optics).

The detector unit is different for WDXRF and for EDXRF spectrometers. WDXRF spectrometers take

advantage of the dispersion of the emitted radiation by diffraction by a crystal or a synthetic multilayer.

The detector does not need to be capable of energy discrimination. EDXRF spectrometers use an

energy-dispersive detector. Pulses of current from the detector, which are a measure of the energy of

the incoming X-rays, are segregated into channels according to energy using an MCA.

NOTE 1 The use of a high-energy X-ray tube increases the potential for losses of volatile analytes from samples

by heating in the spectrometer during analysis.
4 © ISO 2021 – All rights reserved
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SIST EN ISO 22940:2021
ISO 22940:2021(E)

NOTE 2 The new generation of EDXRF spectrometers takes advantage of the polarizing target theory. The

excitation is performed by polarized radiation. The emitted X-ray fluorescence radiation is detected along the

direction of polarization, resulting in a significant decrease of the background scattering, therefore lower limits

of detection can be achieved (comparable to WDXRF).

7.2 Pellet press, capable of providing a pressure of at least 30 kN. The pellet press may be a cold press

or a hot mould press, operating at temperatures not exceeding 180 °C.
8 Interferences and sources of error

Interferences in X-ray fluorescence spectrometry are due to spectral line overlaps, matrix effects,

spectral artefacts and particle size or mineralogical effects.

Spectral line overlaps occur when an analytical line cannot be resolved from the line of a different

element. Corrections for these interferences are made using the algorithms provided with the

instrument software.

Matrix effects occur when the X-ray fluorescence radiation from the analyte element is absorbed or

enhanced by other elements in the sample before it reaches the detector. In the case of complex matrices,

these effects generally shall be corrected. The correction procedure depends on the X-ray fluorescence

spectrometry system (EDXRF or WDXRF) and the apparatus type itself.

Spectral artefacts, for example escape peaks, sum peaks, pulse pile up lines, dead time and continuous

radiation (Bremsstrahlung) correction, are accounted for by the provided instrument software.

Spectral artefacts differ for energy-dispersive and wavelength-dispersive XRF spectrometry.

9 Sample preparation
9.1 Preparation principles

The sample preparation is very critical for XRF analysis of solid recovered fuels. The quality of sample

preparation strongly influences the accuracy of the results. The following different options exist:

— For quantitative analysis of solid recovered fuel samples, the preparation of pressed pellets from

prepared general analysis sample material is recommended.

— For semiquantitative analysis of solid recovered fuels, the general analysis material may be used

directly (in powder form); conce
...

SLOVENSKI STANDARD
oSIST prEN ISO 22940:2020
01-november-2020
Trdna alternativna goriva - Določevanje elementne sestave z rentgensko
fluorescenco (ISO/DIS 22940:2020)

Solid recovered fuels - Determination of elemental composition by X-ray fluorescence

(ISO/DIS 22940:2020)
Feste Sekundärbrennstoffe - Bestimmung der Elementzusammensetzung durch
Röntgenfluoreszenz (ISO/DIS 22940:2020)

Combustibles solides de recuperation - Détermination de la composition élémentaire par

fluorescence de rayons X (ISO/DIS 22940:2020)
Ta slovenski standard je istoveten z: prEN ISO 22940
ICS:
75.160.10 Trda goriva Solid fuels
oSIST prEN ISO 22940:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 22940:2020
---------------------- Page: 2 ----------------------
oSIST prEN ISO 22940:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 22940
ISO/TC 300 Secretariat: SFS
Voting begins on: Voting terminates on:
2020-09-10 2020-12-03
Solid recovered fuels — Determination of elemental
composition by X-ray fluorescence

Combustibles solides de recuperation — Détermination de la composition élémentaire par fluorescence de

rayons X
ICS: 75.160.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 22940:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020
---------------------- Page: 3 ----------------------
oSIST prEN ISO 22940:2020
ISO/DIS 22940:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 22940:2020
ISO/DIS 22940:2020(E)
Contents Page

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

Introduction ..................................................................................................................................................................................................................................v

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Safety remarks ........................................................................................................................................................................................................ 3

5 Symbols and abbreviated terms ........................................................................................................................................................... 3

5.1 Symbols ......................................................................................................................................................................................................... 3

5.2 Abbreviated terms ............................................................................................................................................................................... 4

6 Principle ........................................................................................................................................................................................................................ 4

7 Apparatus ..................................................................................................................................................................................................................... 4

8 Interferences and sources of error .................................................................................................................................................... 5

9 Sample preparation ........................................................................................................................................................................................... 5

9.1 Preparation principles ...................................................................................................................................................................... 5

9.2 Drying of general analysis sample material ................................................................................................................... 5

9.3 Preparation of pressed pellet ..................................................................................................................................................... 6

10 Procedure..................................................................................................................................................................................................................... 6

10.1 Analytical measurement conditions ..................................................................................................................................... 6

10.1.1 Wavelength dispersive instruments ............................................................................................................... 6

10.1.2 Energy dispersive instruments ........................................................................................................................... 7

10.1.3 Intensities and background corrections ...................................................................................................... 7

10.2 Calibration .................................................................................................................................................................................................. 8

10.2.1 General...................................................................................................................................................................................... 8

10.2.2 General calibration procedure ............................................................................................................................. 8

10.2.3 Calibration procedure using the pressed pellet method (recommended method) 9

10.3 Procedures for correcting matrix effect ............................................................................................................................ 9

10.3.1 Internal standard correction using Compton (incoherent) scattering method ........ 9

10.3.2 Fundamental parameter approach ...............................................................................................................10

10.3.3 Fundamental or theoretical influence coefficient method .......................................................10

10.3.4 Empirical alpha correction .................. .................................................................................................................11

10.4 Analysis of the samples .................................................................................................................................................................11

11 Quality control .....................................................................................................................................................................................................12

11.1 Drift correction procedure .........................................................................................................................................................12

11.2 Reference materials and quality control samples .................................................................................................12

12 Calculation of the result .............................................................................................................................................................................12

13 Performance characteristics .................................................................................................................................................................12

14 Test report ................................................................................................................................................................................................................13

Annex A (informative) Publicly available solid recovered fuel reference materials .......................................14

Annex B (informative) Validation .........................................................................................................................................................................15

Bibliography .............................................................................................................................................................................................................................35

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oSIST prEN ISO 22940:2020
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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 on 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 the following

URL: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 300, Solid Recovered Fuels.

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.
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Introduction

X-ray fluorescence spectrometry can be used as a fast method for a qualitative overview of ash forming

elements and impurities. When calibration is based on reference materials or on matrix-matched

homogeneous solid recovered fuel samples with known content, X-ray fluorescence spectrometry can

be used for a quantitative analysis of the total content of the specified elements within different solid

recovered fuels.

The quality of the results obtained depends very closely on the type of instrument used, e.g. bench

top or high performance, energy dispersive or wavelength dispersive instruments. When selecting a

specific instrument, several factors have to be considered, such as the matrices to be analysed, elements

to be determined, detection limits required and the measuring time.

Due to the wide range of matrix compositions and the lack of suitable reference materials in the case

of solid recovered fuels from various origin, it is generally difficult to set up a calibration with matrix-

matched reference materials. Therefore, it is important to use several homogenized solid recovered

fuel samples with properties that sufficiently match the matrices of interest and whose content has

been derived by independent measurement techniques, e.g. total digestion of solid recovered fuels and

characterization of major and minor elements by measurement of digestion solutions with ICP-MS or

ICP-OES or by other techniques like elemental analysis using combustion technology on sulfur or by

combustion and ion chromatographic determination for chlorine.
Therefore, this document describes two different procedures:

1) Quantitative analytical procedure for major elements of solid recovered fuels. The calibration is

based on different reference materials and solid recovered fuel samples with known content.

The elements described as major elements of solid recovered fuels are in fact major elements of the

fuel ashes more than of the fuels. The determination of these elements may be helpful to predict the

melting behaviour and slagging of the ashes. Moreover, contamination of fuel with sand or soil is

indicated by high values of several elements.

2) Total element characterization at a semi-quantitative level for major and minor elements of solid

recovered fuels. The calibration is based on matrix-independent calibration curves, previously set

up by the manufacturer.

In general, the sensitivity of X-ray fluorescence is not sufficient for a determination of the content of

minor elements (trace metals) in solid recovered fuels. However, determination of minor elements

after calibration with solid recovered fuel samples with known content or at a semi-quantitative

level based on matrix-independent calibration curves could be used to collect data for higher

sample numbers taking into account lower achievable precision. Therefore, it may be used to reveal

excessive contents of minor elements in solid recovered fuels.
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oSIST prEN ISO 22940:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 22940:2020(E)
Solid recovered fuels — Determination of elemental
composition by X-ray fluorescence
1 Scope

This document specifies the procedure for a determination of major and minor element concentrations

in solid recovered fuel material by energy dispersive X-ray fluorescence (EDXRF) spectrometry or

wavelength dispersive X-ray fluorescence (WDXRF) spectrometry using a calibration with solid

recovered fuel reference materials or solid recovered fuel samples with known content. A semi-

quantitative determination may be carried out using matrix independent standards.

X-ray fluorescence spectrometry may be used as a fast method for a qualitative overview of elements

and impurities and after suitable calibration it is very useful for determining major elements or even

minor elements (except Hg) in order to quickly identify increased concentrations of minor elements in

solid recovered fuels (e.g. during SRF-production).

This document is applicable for the following elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co,

Ni, Cu, Zn, As, Br, Mo, Cd, Sb, Sn, Tl and Pb. Concentrations from approximately 0,000 1 % and above can

be determined depending on the element, the calibration materials used and the instrument used.

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 21637:—, Solid recovered Fuels — Terminology, definitions and descriptions
ISO 21646:—, Solid recovered fuels — Sample preparation

ISO 21660-3:—, Solid recovered fuels — Determination of moisture content using the oven dry method —

Part 3: Moisture in general analysis sample
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 21637:— and the

following apply.
3.1
absorption edge
abrupt change in mass absorption coefficient at a specific wavelength or energy
3.2
absorption of X-rays

loss of intensity of X-rays through absorption by an isotropic and homogenous material as described by

the Beer-Lambert law
1) Under preparation. (Stage at the time of publication ISO/FDIS 21637.)
2) Under preparation. (Stage at the time of publication ISO/CD 21646)
3) Under preparation. (Stage at the time of publication ISO/DIS 21660-3.)
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3.3
analytical line

specific characteristic X-ray spectral line of the atom or ion of the analyte used for determination of the

analyte content
3.4
continuous radiation

electromagnetic radiation produced by the acceleration of a charged particle, such as an electron, when

deflected by another charged particle, such as an atomic nucleus
3.5
compton-line

spectral line due to incoherent scattering (Compton-effect), occurring when the incident X-ray photon

strikes an atom without promoting fluorescence

Note 1 to entry: Energy is lost in the collision and therefore, the resulting scattered X-ray photon is of lower

energy than the incident X-ray photon.
3.6
drift correction monitors
physically stable samples used to correct for instrumental drift
3.7
emitted sample X-rays

radiation emitted by sample consisting of X-ray fluorescence radiation (3.14) and scattered primary

X-rays (3.12)
3.8
mass absorption coefficient

constant describing the fractional decrease in the intensity of a beam of X-radiation as it passes through

an absorbing medium
Note 1 to entry: It is expressed in cm /g.

Note 2 to entry: The mass absorption coefficient is a function of the wavelength of the absorbed radiation and the

atomic number of the absorbing element.
3.9
polarised excitation X-ray spectrometer

energy dispersive X-ray spectrometer where the excitation is performed by polarised radiation and the

emitted X-ray fluorescence radiation (3.14) is detected along the direction of polarisation

3.10
powder sample
analyte sample submitted as a powder for direct measurement in the sample cup
3.11
pressed pellet
analyte sample prepared by pressing milled material into a disk
3.12
primary X-rays
X-rays by which the sample is radiated
3.13
quality control sample

stable sample with known contents, e.g. (certified) reference material (CRM) or homogenized solid

recovered fuel samples from known origin which contents have been derived by independent analysis

used to monitor instrument and calibration performance
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3.14
X-ray fluorescence radiation

emission of characteristic X-rays from a sample that has been bombarded by high-energy X-rays or

gamma rays
4 Safety remarks

The X-ray fluorescence spectrometer shall comply with international and national regulations relevant

to radiation protection.

The person responsible for managing or supervising the operation of X-ray equipment shall provide

evidence of his knowledge of radiation protection according to national regulations.

5 Symbols and abbreviated terms
5.1 Symbols
Al Aluminium
As Arsenic
Br Bromine
Ca Calcium
Cd Cadmium
Cl Chlorine
Co Cobalt
Cr Chromium
Cu Copper
Fe Iron
K Potassium
Mg Magnesium
Mn Manganese
Mo Molybdenum
Na Sodium
Ni Nickel
P Phosphorus
Pb Lead
S Sulphur
Sb Antimony
Si Silicon
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Sn Tin
Ti Titanium
Tl Thallium
V Vanadium
Zn Zinc
5.2 Abbreviated terms
EDXRF Energy dispersive X-ray fluorescence
MCA Multi-Channel Analyser
WDXRF Wavelength dispersive X-ray fluorescence
6 Principle

After a suitable preparation, the sample is introduced into a XRF-spectrometer and excited by primary

X-rays. The intensities of the secondary fluorescent energy lines specific for each element are measured

and the elemental composition of the sample is determined by reference to previously established

calibration graphs or equations and applying corrections for inter-element effects. The calibration

equations and inter-element corrections are established using pure reagents and/or series of internal or

reference materials provided that they meet all the requirements of the relevant preparation technique.

7 Apparatus

7.1 X-ray fluorescence spectrometer shall be able to analyse the elements according to the scope of

this document. The following types of X-ray fluorescence spectrometers are applicable:

− energy dispersive X-ray fluorescence (EDXRF) spectrometer that achieves the dispersion of the

emitted X-ray fluorescence radiation by an energy dispersive detector;

− wavelength dispersive X-ray fluorescence (WDXRF) spectrometer that achieves the dispersion of

the emitted X-ray fluorescence radiation by diffraction by a crystal or a synthetic multilayer.

The spectrometer consists of the following components:
− primary X-ray source, an X-ray tube with a high voltage generator;
− sample holder;
− detector unit including electronic equipment;

− source modifiers to modify the shape or intensity of the source spectrum or the beam shape (like

source filters, secondary targets, polarizing targets, collimators, focusing optics, etc.).

The detector unit is different for WDXRF and for EDXRF spectrometers. WDXRF spectrometers take

advantage of the dispersion of the emitted radiation by diffraction by a crystal or a synthetic multilayer.

The detector does not need to be capable of energy discrimination. EDXRF spectrometers use an energy

dispersive detector. Pulses of current from the detector, which are a measure of the energy of the incoming

X-rays, are segregated into channels according to energy using a Multi-Channel Analyser (MCA).

NOTE 1 The use of a high-energy X-ray tube increases the potential for losses of volatile analytes from samples

by heating in the spectrometer during analysis.
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NOTE 2 The new generation of EDXRF spectrometers takes advantage of the polarizing target theory resulting

in a significant decrease of the background scattering, and therefore lower limits of detection can be achieved

(comparable to WDXRF).

7.2 Pellet press, capable of providing a pressure of at least 30 kN. The pellet press may be a cold press

or a hot mould press, operating at temperatures not exceeding 180 °C.
8 Interferences and sources of error

Interferences in X-ray fluorescence spectrometry are due to spectral line overlaps, matrix effects,

spectral artefacts and particle size or mineralogical effects.

Spectral line overlaps occur when an analytical line cannot be resolved from the line of a different

element. Corrections for these interferences are made using the algorithms provided with the

instrument software.

Matrix effects occur when the X-ray fluorescence radiation from the analyte element is absorbed

or enhanced by other elements in the sample before it reaches the detector. In the case of complex

matrices, these effects generally have to be corrected. The correction procedure depends on the X-ray

fluorescence spectrometry system (EDXRF or WDXRF) and the apparatus type itself.

Spectral artefacts, e.g. escape peaks, sum peaks, pulse pile up lines, dead time, Bremsstrahlung

correction, are accounted for by the provided instrument software. Spectral artefacts differ for energy

dispersive and wavelength dispersive XRF spectrometry.
9 Sample preparation
9.1 Preparation principles

The sample preparation is very critical for XRF analysis of solid recovered fuels. The quality of sample

preparation strongly influences the accuracy of the results. The following different options exist:

− For quantitative analysis of solid recovered fuel samples, the preparation of pressed pellets from

prepared general analysis sample material is recommended.

− For semi-quantitative analysis of solid recovered fuels, the general analysis material may be used

directly (in powder form) and concerning samples of solid recovered fuel pellets, the original

pellets may be used directly without any sample preparation. It may be used to provide fast basic

information about the approximate composition of a sample. Similar results may be obtained using

portable XRF instruments for field analysis.

For a given calibration, the same preparation method shall be used throughout, for both samples and

standards.

For precise quantitative measurements, homogeneous and representative test portions are necessary.

The nominal top size of the material shall be 0,5 mm or less, according to ISO 21646:—.

9.2 Drying of general analysis sample material

Dry a sufficient amount of general analysis sample material according to ISO 21660-3:— immediately

before pressing pellets for XRF-analysis.

NOTE Concerning some XRF-instruments, the applied vacuum will dry the general analysis sample material

during the determination giving the same results as if the sample was previously dried.

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9.3 Preparation of pressed pellet

A pellet is prepared in the pellet press (7.2). Before pressing, the sample shall be mixed and homogenized.

Use the same weight for any single set of standards and samples and add binder (e.g. wax or liquid

organic binder), if necessary.
For the preparation, follow the manufacturer’s instructions.

NOTE 1 Different binders can be used. In case of organic liquid binders (~ 0,6 % weight of sample) the pressed

pellet will be placed in an oven at between 70-100 °C for a minimum of 10 minutes to evaporate the organic

solvent or for the formation of long chain polymers formed by heating (e.g. PVP-methylcellulose binders).

NOTE 2 In case of wax binder the ratio of the sample weight to wax is around 10:1.

10 Procedure
10.1 Analytical measurement conditions
10.1.1 Wavelength dispersive instruments

The analytical lines to be used and suggested operating conditions are given in Table 1. The settings

strongly depend on the spectrometer configuration, e.g. the type of X-ray tube (Rh, Cr), tube power,

available crystals, type of collimators. Instrument manufacturer’s recommendations should be followed

in all cases.
10.1.1.1 Intensities and background corrections

For the determination of trace elements, the measured intensities have to be background corrected.

The measured background positions should be free of spectral line interferences. The net peak intensity,

I , expressed as the number of counts per second of the element of interest (i), is calculated as the

difference between the measured peak intensity of the element and the background intensity, as given

in Formula (1):
II=−I (1)
where

I is the count rate of the element i, expressed as the number of counts per second;

I is the background count rate of the element i with no analyte present, expressed as the number

of counts per second.
10.1.1.2 Counting time

The minimum counting time is the time necessary to achieve an uncertainty (2σ ), which is less than

the desired precision of the measurement. Choose a reference material or quality control sample with a

concentration level in the middle of the working range and measure the count rate. The counting time

for each element can be calculated according to Formula (2):
T =− ()100//21σ xI I (2)
% pb
where
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