ISO 15238:2016

Solid mineral fuels - Determination of total cadmium content of coal

ISO 15238:2016 specifies a procedure for the determination of the total cadmium content of coal. This procedure has not been validated with coals that spontaneously ignite. Prior to use with such sample types, users should validate the method.

Combustibles minéraux solides — Dosage du cadmium total dans le charbon

General Information

• Status: Published
• Publication Date: 17-Nov-2016
• ICS: 73.040 - Coals
• Technical Committee: ISO/TC 27/SC 5 - Methods of analysis
• Drafting Committee: ISO/TC 27/SC 5/WG 8 - Major, minor and trace elements in coal and coal residues
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 04-Jul-2025
• Completion Date: 13-Dec-2025

Relations

• Revised: ISO 15238:2025 - Coal - Determination of total cadmium
• Effective Date: 27-May-2023
• Revises: ISO 15238:2003 - Solid mineral fuels - Determination of total cadmium content of coal
• Effective Date: 21-Nov-2015

Overview

ISO 15238:2016 defines a standardized method for the determination of total cadmium content in coal, providing critical guidance for laboratories and industry professionals involved in coal quality analysis. This international standard specifies a precise analytical procedure employing graphite furnace atomic absorption spectroscopy (GFAAS), ensuring reliable, reproducible quantification of cadmium, a toxic heavy metal. The method involves ashing the coal sample, acid digestion of the ash, and subsequent elemental analysis. ISO 15238:2016 is essential for environmental monitoring, regulatory compliance, and quality control in the coal industry.

Key Topics

• Sample Preparation: Coal is ashed at controlled temperatures to remove volatile components while preserving inorganic residue for analysis.
• Acid Digestion: Ash is dissolved using a mixture including aqua regia and hydrofluoric acid to ensure complete cadmium extraction.
• Graphite Furnace Atomic Absorption Spectroscopy (GFAAS): Selected for its sensitivity and accuracy in detecting trace cadmium levels in dissolved samples.
• Calibration and Standards: Use of matrix-matched cadmium standards and blank solutions to ensure accurate calibration and quantification.
• Result Calculation: Cadmium content is calculated in nanograms per gram (ng/g) on an "as analyzed" basis, with options for moisture and ash content corrections.
• Precision Metrics: The standard specifies repeatability limits and reproducibility critical differences to gauge analytical consistency.
• Safety Considerations: Handling of toxic and corrosive reagents, especially hydrofluoric acid, requires strict adherence to safety protocols.
• Scope Limitations: The procedure has not been validated for spontaneously igniting coals; users must validate the method if applied to such samples.

Applications

• Environmental Monitoring: Assessing coal for cadmium content helps evaluate potential emissions of toxic heavy metals during combustion, guiding environmental impact assessments.
• Quality Control in Coal Mining and Processing: Regular cadmium quantification ensures coal products meet industry and regulatory standards for hazardous substances.
• Regulatory Compliance: Supports meeting national and international regulations limiting cadmium emissions and contamination from coal usage.
• Research and Development: Used by scientific institutions studying heavy metal distribution in coal deposits and their behavior during coal conversion processes.
• Risk Assessment: Enables better understanding of occupational and environmental risks associated with cadmium exposure in coal handling and utilization.
• Waste Management: Helps evaluate the toxic metal content in coal combustion residues for safe disposal or recycling.

Related Standards

• ISO 1170 – Coal and coke - Calculation of analyses to different bases: Relevant for transforming cadmium content results expressed on various moisture or ash bases.
• ISO 3696 – Water Specifications for analytical laboratory use: Ensures the purity of water used in sample preparation and reagent dilutions.
• ISO 5068-2 & ISO 5069-2 – Methods for determining moisture content and sampling preparation of brown coals and lignites: Support proper sample conditioning prior to cadmium analysis.
• ISO 13909-4 – Mechanical sampling of hard coal and coke: Provides guidance on representative sample preparation for accurate testing.
• ISO/IEC Directives – Editorial and procedural rules for developing ISO standards, ensuring consistent document quality and maintenance.

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By following ISO 15238:2016, laboratories achieve accurate, reproducible cadmium measurements in coal, enabling safer industrial practices, environmental stewardship, and compliance with heavy metal regulations. This standard is an indispensable reference for professionals engaged in coal analysis and quality assurance worldwide.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 15238
Second edition
2016-11-15
Solid mineral fuels — Determination
of total cadmium content of coal
Combustibles minéraux solides — Dosage du cadmium total dans
le charbon
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
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ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Preparation of sample . 2
8 Procedure. 3
8.1 Ashing of coal sample . 3
8.2 Preparation of test solution . 3
8.3 Preparation of blank solution . 3
8.4 Graphite-furnace atomic absorption analysis . 3
8.4.1 Calibration . 3
8.4.2 Measurement of standards . 3
8.4.3 Measurement of test solution . 4
8.4.4 Measurement of blank solution . 4
9 Expression of results . 4
9.1 Ash content . 4
9.2 Cadmium content . 4
10 Precision . 5
10.1 Repeatability limit . 5
10.2 Reproducibility critical difference . 5
11 Test report . 5
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
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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
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on the ISO list of patent declarations received (see www.iso.org/patents).
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For an explanation on 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.
The committee responsible for this document is ISO/TC 27, Solid mineral fuels, Subcommittee SC 5,
Methods of analysis.
This second edition cancels and replaces the first edition (ISO 15238:2003), of which it constitutes a
minor revision. This document incorporates changes related to dated references and other minor items
following its systematic review.
iv © ISO 2016 – All rights reserved

INTERNATIONAL STANDARD ISO 15238:2016(E)
Solid mineral fuels — Determination of total cadmium
content of coal
1 Scope
This document specifies a procedure for the determination of the total cadmium content of coal.
This procedure has not been validated with coals that spontaneously ignite. Prior to use with such
sample types, users should validate the method.
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 1170, Coal and coke — Calculation of analyses to different bases
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 5068-2, Brown coals and lignites — Determination of moisture content — Part 2: Indirect gravimetric
method for moisture in the analysis sample
ISO 5069-2, Brown coals and lignites — Principles of sampling — Part 2: Sample preparation for
determination of moisture content and for general analysis
ISO 13909-4, Hard coal and coke — Mechanical sam
...