Jewellery and precious metals - Determination of gold - Cupellation method (fire assay) (ISO 11426:2021)

Schmuck und Edelmetalle - Bestimmung von Gold - Dokimastisches Verfahren (ISO 11426:2021)

Dieses Dokument legt ein dokimastisches Verfahren (Kupellationsverfahren) zur Bestimmung von Gold in Materialien, die als homogen betrachtet werden, fest. Der Goldgehalt der Legierung sollte vorzugsweise zwischen 100 Promille und 999,5 Promille (‰) liegen. Feingehalte über 999,5 ‰ können durch eine spektroskopisches Differenzverfahren (z. B. ISO 15093) bestimmt werden.
Das Verfahren ist anwendbar für die meisten Arten von Goldproben. Einige Modifikationen sind für bestimmte Fälle angegeben (Vorhandensein einer großen Menge unedler Metalle, Platin oder Palladium, Silber). Es ist nicht kompatibel mit dem Vorhandensein von Iridium, Rhodium und Ruthenium über den Spuren (mehr als 0,25 ‰ für die Summe aller drei Elemente).
Dieses Verfahren ist als empfohlenes Verfahren zur Bestimmung der Feinheit von Schmucklegierungen nach ISO 9202 vorgesehen.

Joaillerie, bijouterie et métaux précieux - Dosage de l'or - Méthode de coupellation (essai au feu) (ISO 11426:2021)

Nakit in plemenite kovine - Določevanje zlata - Odtopitev primesi v tekočem svincu (ISO 11426:2021)

General Information

Status
Published
Public Enquiry End Date
31-Oct-2020
Publication Date
28-Apr-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Apr-2021
Due Date
06-Jun-2021
Completion Date
29-Apr-2021

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SLOVENSKI STANDARD
SIST EN ISO 11426:2021
01-junij-2021
Nadomešča:
SIST EN ISO 11426:2016

Nakit in plemenite kovine - Določevanje zlata - Odtopitev primesi v tekočem svincu

(ISO 11426:2021)

Jewellery and precious metals - Determination of gold - Cupellation method (fire assay)

(ISO 11426:2021)
Schmuck und Edelmetalle - Bestimmung von Gold - Dokimastisches Verfahren (ISO
11426:2021)

Joaillerie, bijouterie et métaux précieux - Dosage de l'or - Méthode de coupellation (essai

au feu) (ISO 11426:2021)
Ta slovenski standard je istoveten z: EN ISO 11426:2021
ICS:
39.060 Nakit Jewellery
SIST EN ISO 11426:2021 en,fr,de

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

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SIST EN ISO 11426:2021
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SIST EN ISO 11426:2021
EN ISO 11426
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2021
EUROPÄISCHE NORM
ICS 39.060 Supersedes EN ISO 11426:2016
English Version
Jewellery and precious metals - Determination of gold -
Cupellation method (fire assay) (ISO 11426:2021)

Joaillerie, bijouterie et métaux précieux - Dosage de l'or Schmuck und Edelmetalle - Bestimmung von Gold -

- Méthode de coupellation (essai au feu) (ISO Dokimastisches Verfahren (ISO 11426:2021)

11426:2021)
This European Standard was approved by CEN on 18 December 2020.

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 11426:2021 E

worldwide for CEN national Members.
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SIST EN ISO 11426:2021
EN ISO 11426:2021 (E)
Contents Page

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

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SIST EN ISO 11426:2021
EN ISO 11426:2021 (E)
European foreword

This document (EN ISO 11426:2021) has been prepared by Technical Committee ISO/TC 174 "Jewellery

and precious metals" in collaboration with CCMC.

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 September 2021, and conflicting national standards

shall be withdrawn at the latest by September 2021.

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.

This document supersedes EN ISO 11426:2016.

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 11426:2021 has been approved by CEN as EN ISO 11426:2021 without any modification.

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SIST EN ISO 11426:2021
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SIST EN ISO 11426:2021
INTERNATIONAL ISO
STANDARD 11426
Fourth edition
2021-03
Jewellery and precious metals —
Determination of gold — Cupellation
method (fire assay)
Joaillerie, bijouterie et métaux précieux — Dosage de l'or — Méthode
de coupellation (essai au feu)
Reference number
ISO 11426:2021(E)
ISO 2021
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SIST EN ISO 11426:2021
ISO 11426:2021(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
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SIST EN ISO 11426:2021
ISO 11426:2021(E)
Contents Page

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

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

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

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

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

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

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

7 Sampling ........................................................................................................................................................................................................................ 3

8 Procedure..................................................................................................................................................................................................................... 3

8.1 Method selection ................................................................................................................................................................................... 3

8.2 General method ...................................................................................................................................................................................... 3

8.2.1 Assay samples .................................................................................................................................................................... 3

8.2.2 Proof samples ..................................................................................................................................................................... 4

8.2.3 Cupellation and treatment of precious metal buttons .................................................................... 4

8.2.4 Parting of the silver/gold samples ................................................................................................................... 4

8.3 Sample with large amount of base metals....................................................................................................................... 5

8.4 Sample containing platinum or palladium...................................................................................................................... 5

8.5 Sample with a silver/gold ratio higher than 3 ............................................................................................................. 5

9 Calculation and expression of results ............................................................................................................................................. 5

9.1 Proof sample factor ............................................................................................................................................................................. 5

9.2 Calculation of gold content ........................................................................................................................................................... 6

9.3 Repeatability ............................................................................................................................................................................................. 6

10 Test report ................................................................................................................................................................................................................... 6

Annex A (informative) Concentration of other base metals, affecting the gold result .....................................7

Bibliography ................................................................................................................................................................................................................................ 8

© ISO 2021 – All rights reserved iii
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SIST EN ISO 11426:2021
ISO 11426:2021(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 174, Jewellery and precious metals, in

collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/

SS M21, Precious metals - Applications in jewellery and associated products, in accordance with the

Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This fourth edition cancels and replaces the third edition (ISO 11426:2014), which has been technically

revised.
The main changes compared to the previous edition are as follows:

— extension of the scope to cover determination of gold in multiple types of alloys, not only in

jewellery ones;
— purity of proof samples was re-defined in Clause 5;

— specific procedures are described in Clause 8 for samples with large amount of base metals,

containing platinum or palladium, or with a silver/gold ratio higher than 3;

— calculation was adapted to take into account the addition of pure gold and the fineness of the gold

used in the proof sample;
— repeatability requirements were changed;
— the use of scorification was removed.

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 11426:2021
INTERNATIONAL STANDARD ISO 11426:2021(E)
Jewellery and precious metals — Determination of gold —
Cupellation method (fire assay)
1 Scope

This document specifies a cupellation method (fire assay) for the determination of gold on a material

considered homogeneous. The gold content of the sample lies preferably between 100 and 999,5 parts

per thousand (‰) by weight. Fineness above 999,5 ‰ can be determined using a spectroscopy method

by difference (e.g. ISO 15093).

The procedure is applicable to most types of gold samples. Some modifications are indicated for specific

cases (presence of large amount of base metals, platinum or palladium, silver). It is not compatible with

the presence above trace levels of iridium, rhodium and ruthenium (more than 0,25 ‰ for the sum of

all three elements).

This method is also intended to be used as the recommended method for the determination of fineness

in jewellery alloys covered by ISO 9202.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in s
...

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