ISO/TS 22451:2021

TECHNICAL ISO/TS
SPECIFICATION 22451
First edition
2021-05
Recycling of rare earth elements —
Methods for the measurement of rare
earth elements in industrial waste and
end-of-life products
Recyclage des éléments des terres rares — Méthodes pour le
mesurage des éléments des terres rares dans les déchets industriels et
les produits en fin de vie
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 1
4 Sampling . 2
4.1 Industrial waste . 2
4.1.1 Processing waste. 2
4.1.2 Scrap . 2
4.2 End-of-life products . 2
4.2.1 Magnets . 2
4.2.2 NiMH batteries . . 2
4.2.3 Phosphors . 2
5 Selection of measurement methods . 3
6 Measurement methods . 3
6.1 X-ray fluorescence spectrometry (XRF) . 3
6.1.1 General. 3
6.1.2 Sample preparation . 3
6.1.3 Calibration . 4
6.1.4 Analysis and calculation . 4
6.2 ICP-OES . 5
6.2.1 General. 5
6.2.2 Sample preparation . 5
6.2.3 Calibration . 5
6.2.4 Analysis and calculation . 5
6.3 ICP-MS . 6
6.3.1 General. 6
6.3.2 Sample preparation . 6
6.3.3 Calibration . 6
6.3.4 Analysis and calculation . 6
Annex A (informative) Example measurement report . 8
Bibliography . 9
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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This document was prepared by Technical Committee ISO/TC 298, Rare earth.
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iv © ISO 2021 – All rights reserved

Introduction
With technical advancement, rare earth elements (REEs) are increasingly important due to their
importance in a number of applications, including green technologies. However, there are high supply
risks arising from the dependence on a single source of extraction. Recycling and systemic management
of rare earth elements are key issues for solving the waste and supply risks of REEs.
In order to efficiently recycle and systemically manage rare earth elements, a standard measurement
method of REEs in industrial wastes and end-of-life cycled products is needed. Industrial wastes and
end-of-life products can be found in solid, solid-liquid mixture and liquid forms. For example, machining
waste contains chips and flakes with coolant oils, greases and numerous other forms of aqueous and
non-aqueous contaminants. Similarly, waste liquid slurries contain REEs, as in LEDs, and batteries
contain numerous acids, bases etc. Furthermore, in order to verify the information provided by the
producer about REEs in the waste, standardized measurement procedure is necessary.
There are several scientific methods for quantitatively measure REEs in matters, such as X-ray
fluorescence (XRF), inductively coupled plasma mass spectroscopy (ICP-MS), inductively coupled
plasma optical emission spectroscopy (ICP-OES) and glow discharge mass spectrometry (GD-MS).
However, these different characterization techniques often offer dissimilar measurement results
depending on the composition and physical state of the sample under observation. This is another
reason to establish standard measurement methods.
This document provides a brief overview and several measurement methods for REEs in industrial
wastes and end-of-life products. Sample preparation methods are also provided. The accurate
measurement of rare earth content (e.g. in ppm range) is still under active research and is not covered
by this document. However, this document does provide measurement methods for identifying the
presence and approximate content of rare earth elements.
This document is designed to be used with ISO 22450.
TECHNICAL SPECIFICATION ISO/TS 22451:2021(E)
Recycling of rare earth elements — Methods for the
measurement of rare earth elements in industrial waste
and end-of-life products
1 Scope
This document provides measurement methods for quantifying rare earth elements (REEs) in industrial
wastes and end-of-life products in solid, solid-liquid mixture or liquid forms. It provides an overview of
sample preparation and measurement of REEs in industrial waste and end-of-life products.
WARNING — The use of this document can involve hazardous materials, operations and
equipment. This document does not address any safety problems associated with its use. It is the
responsibility of the user of this document to establish appropriate safety and health practices.
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 22444-2, Rare earth — Vocabulary — Part 2: Metals and their alloys
ISO 22450, Recycling of rare earth elements — Requirements for providing information on industrial waste
and end-of-life products
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 22444-2 and ISO 22450 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/
3.2 Abbreviated terms
REE rare earth element
TREE total rare earth element content
ppm parts per million
XRF X-ray fluorescence spectrometry
EDXRF energy dispersive X-ray fluorescence spectrometry
WDXRF wavelength dispersive X-ray fluorescence spectrometry
ICP-MS inductively coupled plasma mass spectrometry
ICP-OES inductively coupled plasma optical emission spectrometry
[also referred to as inductively coupled plasma atomic emission spectroscopy (ICP-AES)]
4 Sampling
4.1 Industrial waste
4.1.1 Processing waste
Processing waste can be of solid or liquid type. In the case of solid waste, sampling can be done directly
without any special pre-treatment. In the case of liquid waste, it should be ensured that the sample is
safe to handle and does not contain any hazardous components. For that purpose, the pH of the waste
should be checked and neutralized. After the safety of the liquid waste is established, it should be
prepared for analysis. Because processing waste ca
...