ISO 15237:2016

Solid mineral fuels - Determination of total mercury content of coal

ISO 15237:2016 specifies a procedure for the determination of the total mercury content of coal.

Combustibles minéraux solides — Dosage du mercure 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: 09-May-2025
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 10848-5:2020 - Acoustics - Laboratory and field measurement of the flanking transmission for airborne, impact and building service equipment sound between adjoining rooms - Part 5: Radiation efficiencies of building elements
• Effective Date: 06-Jun-2022
• Revised: ISO 15237:2025 - Coal - Determination of total mercury
• Effective Date: 27-May-2023
• Revises: ISO 15237:2003 - Solid mineral fuels - Determination of total mercury content of coal
• Effective Date: 21-Nov-2015

Overview

ISO 15237:2016 sets the international standard for determining the total mercury content in coal, a critical measure in assessing environmental and health impacts of coal use. Developed by ISO/TC 27 (Solid mineral fuels), this method utilizes a precise oxygen bomb combustion procedure followed by atomic absorption spectrometry to quantify mercury accurately. The standard replaces the previous 2003 edition, providing a technically updated protocol to ensure repeatability, reproducibility, and unbiased results in mercury detection within solid mineral fuels.

Key Topics

• Scope and Purpose
  Specifies a reliable analytical procedure for total mercury measurement in coal samples, crucial due to mercury’s volatility and environmental risk during combustion.

• Sample Preparation
  Utilizes test samples prepared in accordance with other ISO standards (e.g., ISO 5069-2, ISO 13909-4) ensuring representative, equilibrium-moisture coal specimens for analysis.

• Oxygen Bomb Combustion
  Coal samples (~1 g) are combusted inside a mercury-free oxygen bomb under controlled oxygen pressure, capturing mercury species produced during combustion in water.

• Reagents and Apparatus
  Requires analytical grade reagents such as stannous chloride solution, potassium permanganate, and hydroxylammonium chloride. Instrumentation involves an atomic absorption spectrometer with flameless cold-vapour mercury detection capabilities.

• Analytical Procedure
  Mercury absorption in water is chemically reduced and quantified via flameless cold vapour atomic absorption spectroscopy. Calibration against matrix-matched mercury standard solutions ensures accuracy.

• Quality Control
  Includes blank determinations and precision metrics like repeatability limits and reproducibility critical differences to guarantee confident mercury quantification.

Applications

ISO 15237:2016 is essential for laboratories and organizations engaged in:

• Environmental Monitoring
  Measuring mercury emission potential in coal-fired power plants to support regulatory compliance and pollution control programs.

• Coal Quality Control
  Enabling coal producers and consumers to assess elemental mercury content, improving health and safety practices in coal handling and utilization.

• Research and Academic Studies
  Providing a standardized baseline method for mercury content determination encouraging data comparability and method validation.

• Industrial Emission Reduction Strategies
  Facilitating the identification of high-mercury coal batches to inform cleaner combustion technologies and mercury emission mitigation.

Related Standards

• ISO 5069-2: Brown coals and lignites - Principles of sampling - Part 2: Sample preparation for determination of moisture content and analysis
  Establishes procedures for preparing representative coal samples integral to ISO 15237 testing accuracy.

• ISO 13909-4: Hard coal and coke - Mechanical sampling - Part 4: Coal - Preparation of test samples
  Defines mechanical sampling methods to ensure uniform coal samples used in mercury content analysis.

• ISO 3696: Water for analytical laboratory use - Specification and test methods
  Specifies high purity water requirements used in reagents and washing during the mercury determination process.

• ISO 1928: Solid mineral fuels - Determination of gross calorific value by bomb calorimeter method
  Describes the oxygen bomb calorimeter apparatus that also serves as a basis for the combustion system in mercury testing.

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Accurate determination of mercury content in coal following ISO 15237:2016 aids stakeholders in minimizing environmental mercury release, upholding regulatory frameworks, and promoting sustainable coal utilization. Following this internationally recognized standard ensures reliable, reproducible mercury analysis that underpins effective public health and environmental safeguards.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 15237
Second edition
2016-11-15
Solid mineral fuels — Determination
of total mercury content of coal
Combustibles minéraux solides — Dosage du mercure 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
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the requester.
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ii © ISO 2016 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definition . 1
4 Principle . 1
5 Reagents . 1
6 Apparatus . 2
7 Preparation of sample . 3
8 Oxygen bomb combustion procedure . 3
8.1 General . 3
8.2 Combustion of coal . 3
9 Preparation of test solution . 3
10 Atomic absorption analysis . 4
10.1 Calibration . 4
10.2 Analytical procedure . 4
11 Expression of results . 5
12 Precision . 5
12.1 Repeatability limit . 5
12.2 Reproducibility critical difference . 5
13 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
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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
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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 15237:2003), which has been technically
revised. This document incorporates changes related to dated references and other minor items
following its systematic review.
iv © ISO 2016 – All rights reserved

Introduction
Mercury occurs naturally in coal. It is an element that can be released during the combustion process.
The determination of the total mercury content of coal cannot be accomplished satisfactorily by
traditional ashing and digestion procedures because of the volatility of the element.
Quantitive recovery can be achieved by strict adherence to the procedure set out in this document.
Instrumental methods for a more rapid determination of total mercury content are available. If such a
method is to be used, it is important to demonstrate that the method is free from bias, when compared
with this reference method and will give levels of repeatability and reproducibility which are the same,
or better than, those quoted for the reference method (see Clause 10).
INTERNATIONAL STANDARD ISO 15237:2016(E)
Solid mineral fuels — Determination of total mercury
content of coal
1 Scope
This document specifies a procedure for the determination of the total mercury content of coal.
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 1928, Solid mineral fuels — Determination of gross calorific value by the bomb calorimetric method
and calculation of net calorific value
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 sampling — Part 4: Coal — Preparation of test samples
3 Terms and definition
No terms and definitions are defined in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
4 Principle
The sample is burned in an oxygen bomb, the mercury species formed during combustion being
absorbed in water. The mercury species present in the water are reduced by stannous chloride and
quantified by flameless cold vapour atomic absorption spectroscopy.
It is reported that lithium borohydride (LiBH ) and sodium borohydride (NaBH ) are satisfactory for
4 4
the reduction instead of stannous chloride; laboratories using these reductants should demonstrate
that the performance is equivalent to that using stannous chloride.
5 Reagents
WARNING — Care should b
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