ISO 23380:2022

INTERNATIONAL ISO
STANDARD 23380
Third edition
2022-08
Coal — Selection of methods for the
determination of trace elements —
Guidance and requirements
Charbon — Sélection des méthodes de détermination des éléments
traces — Recommandations et exigences
Reference number
ISO 23380:2022(E)
© ISO 2022

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ISO 23380:2022(E)
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© ISO 2022
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Published in Switzerland
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ISO 23380:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 S c op e . 1
2 Nor m at i ve r ef er enc e s . 1
3 Terms and definitions . 1
4 Abbr ev i at ed t er m s . 1
5 Discussion of methods . 2
5.1 G eneral . 2
5.2 A rsenic and selenium . . 2
5.3 B oron . 2
5.4 A ntimony, beryllium, cadmium, chromium, cobalt, copper, lead, manganese,
molybdenum, nickel, thallium, vanadium, zinc, thorium and uranium . 2
5.4.1 G eneral . 2
5.4.2 Radionuclides . 3
5 . 5 C h lor i ne . 3
5 . 6 F luor i ne . 3
5.7 Mercury . 3
6 Use of certified reference materials . 4
7 C alculation of results . 4
8 S en s it i v it y . 4
Annex A (informative) Scheme of analysis for trace elements . 6
Annex B (informative) Alternative dissolution procedures for coal . 7
Bibliography . 8
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ISO 23380:2022(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
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electrotechnical standardization.
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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
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 27, Coal and coke, Subcommittee SC 5,
Methods of analysis.
This third edition cancels and replaces the second edition (ISO 23380:2013) which has been technically
revised.
The main changes are as follows:
— The title has been changed to add "Guidance and requirements";
— Clause 9, Reporting of results including Table 2, Clause 10, Precision and Clause 11, Test Report,
have been 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.
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ISO 23380:2022(E)
Introduction
The determination of trace elements in coal and coke is becoming more important due to the
considerable emphasis being placed on the effect of these elements on the environment. In order to have
accurate and precise results for the analysis of trace elements, it is imperative that standard methods
be available and that these methods be based on reliable procedures.
The objective of this document is to assist in the selection of the appropriate methods available to
determine the common trace elements in coal.
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INTERNATIONAL STANDARD ISO 23380:2022(E)
Coal — Selection of methods for the determination of trace
elements — Guidance and requirements
1 S cope
This document provides guidance and requirements on the selection of methods used for the
determination of trace elements in coal. The trace elements of environmental interest include antimony,
arsenic, beryllium, boron, cadmium, chlorine, chromium, cobalt, copper, fluorine, lead, manganese,
mercury, molybdenum, nickel, selenium, thallium, vanadium and zinc. The radioactive trace elements
thorium and uranium can be added to this list.
This document does not prescribe the methods used for the determination of individual trace elements.
The analysis of appropriate certified reference materials (CRMs) is essential to confirm the accuracy of
any method used (see ISO Guide 33).
2 Normat ive 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 1213-2, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and analysis
ISO 5725 (all parts), Accuracy (trueness and precision) of measurement methods and results
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1213-2 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Abbreviated terms
AAS atomic absorption spectrometry
AFS atomic fluorescence spectrometry
CRM certified reference material
GFAAS graphite-furnace atomic absorption spectrometry
IC ion chromatography
ICP-AES inductively coupled plasma atomic emission spectrometry — often referred to as ICP-OES,
i.e. inductively coupled plasma optical emission spectrometry
ICP-MS inductively coupled plasma mass spectrometry
ISE ion-selective electrode
XRF X-ray fluorescence spectrometry
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ISO 23380:2022(E)
5 Discussion of meth ods
5.1 General
A summary of techniques applicable to the determination of each of the trace elements is discussed
below. A schematic of procedures used for trace element determinations is given in Annex A.
Moisture shall be determined on the sample to enable calculation to bases other than “air-dried”.
Moisture determination is described in ISO 11722.
NOTE 1 There are digestion procedures applicable to unashed coal given in Annex B.
NOTE 2 Boron, chlorine, fluorine, mercury, and selenium are released if coal is ashed; thus, it is not possible to
estimate the mass fraction of these elements in coal by analysing laboratory-prepared ash.
Where digestion procedures require ashing of the coal, ash yield shall be determined to enable
calculation of trace element mass fractions in the coal sample (see Clause 7). Ashing procedures are
described in ISO 15238. Coals are ashed in silica or quartz dishes, or in platinum or platinum alloy
crucibles/basins, in a conventional ashing furnace. The furnace temperature is ramped from ambient
to a maximum of 500 °C over 1 h to 3 h and held at this temperature until the carbonaceous material
is completely oxidized or for a maximum of 18 h. The ramp rate is selected to avoid ignition and
mechanical loss of sample.
5.2 Arsenic and selenium
Arsenic and selenium are determined by hydride generation/atomic absorption or atomic fluorescence
techniques following the ashing of the coal at 800 °C in the presence of Eschka mixture and dissolution
with hydrochloric acid. ISO 11723 is the recommended method for the determination of arsenic and
selenium in coal.
Arsenic can be determined in coal by the analysis of ash prepared in a laboratory at a temperature
no greater than 500 °C. Selenium is vaporized at quite low temperatures and is not recovered in ash.
There is no International Standard for the determination of arsenic in coal ash. A suitable procedure is
the dissolution of the ash either by fusion (lithium tetraborate/metaborate) or by mixed acids (nitric,
hydrochloric, and hydrofluoric acids) and determination of the analyte by hydride/AAS or hydride/
AFS. This element can also be determined by ICP-MS if the interference caused by argon chloride is
eliminated.
5.3 Boron
Boron is determined by ICP-AES following the ashing of the coal at 800 °C in the presence of Eschka
mixture and dissolution with hydrochloric acid (see AS 1038.10.3). This dissolution procedure is the
same as that used for arsenic and selenium. The procedure is set out in ISO 11723.
5.4 Antimon y, beryllium, cadmium, chromium, cobalt, copper, lead, manganese,
molybdenum, nickel, thallium, vanadium, zinc, thorium and uranium
5.4.1 General
Antimony, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel,
thallium, v
...