ISO 1952:2008

INTERNATIONAL ISO
STANDARD 1952
Second edition
2008-09-01

Solid mineral fuels — Determination of
extractable metals in dilute hydrochloric
acid
Combustibles minéraux solides — Détermination des métaux
extractibles dans l'acide chlorhydrique dilué




Reference number
ISO 1952:2008(E)
©
ISO 2008

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ISO 1952:2008(E)
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ii © ISO 2008 – All rights reserved

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ISO 1952:2008(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Principle. 1
4 Reagents and materials . 1
5 Apparatus . 4
6 Preparation of the test sample . 4
7 Procedure . 4
8 Expression of results . 5
9 Precision. 6
10 Test report . 6

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ISO 1952:2008(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 1952 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 5,
Methods of analysis.
This second edition cancels and replaces the first edition (ISO 1952:1976), which has been technically revised.
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ISO 1952:2008(E)
Introduction
Sodium, potassium, calcium, iron and magnesium are commonly present in solid mineral fuel. They can
contribute significantly to coal-utilization problems, such as boiler-tube fouling and ash disposal; they also
affect product quality and gaseous emissions from combustion processes.
Research indicates that the amounts of alkaline and earth-alkaline metals extractable with dilute hydrochloric
acid are more closely related to the fouling/slagging properties of solid mineral fuel than are the total amounts
of the metals.

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INTERNATIONAL STANDARD ISO 1952:2008(E)

Solid mineral fuels — Determination of extractable metals in
dilute hydrochloric acid
1 Scope
This International Standard describes the extraction from solid mineral fuels by dilute hydrochloric acid and
determination of extractable sodium, potassium, calcium, iron and magnesium.
2 Normative references
The following referenced documents are indispensable for the application 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 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 5725-6:1994, Accuracy (trueness and precision) of measurement methods and results — Part 6: Use in
practice of accuracy values
ISO 11722, Solid mineral fuels — Hard coal — Determination of moisture in the general analysis test sample
by drying in nitrogen
ISO 13909-4, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples
3 Principle
A portion of the sample is extracted with hot, dilute hydrochloric acid after wetting of the solid mineral fuel with
alcohol. All forms of sodium, potassium, magnesium, calcium, iron that are exchangeable or extractable with
the hydrochloric acid are extracted from the coal. After removal of the residual solid mineral fuel by filtration,
the concentrations of the elements in the filtrate are determined by atomic absorption spectrometry.
The concentrations of the elements may also be determined by ICP-OES if the instrument has been validated
for the quantification in an appropriate manner.
4 Reagents and materials
Use analytical reagent grade chemicals. Other grades can be used, provided it is documented that the
reagent is of sufficiently high purity to permit its use without adversely affecting the accuracy of the
determination.
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ISO 1952:2008(E)
4.1 Water, high-purity deionized water as defined in ISO 3696, or as defined by the equivalent national
standard.
4.2 Ethanol.
4.3 Hydrochloric acid (HCl).
4.4 Hydrochloric acid, concentrated, ρ = 1,19 g/ml.
20
4.5 Hydrochloric acid solution, prepared by mixing 1 part concentrated hydrochloric acid (4.4) with 1 part
deionized water (4.1).
DANGER — The addition of the strong acid, HCl, to water liberates a significant amount of heat and
can cause a violent reaction.
4.6 Nitric acid (HNO ), concentrated, ρ = 1,42 g/ml.
3 20
4.7 Lanthanum oxide (La O ).
2 3
4.8 Lanthanum solution.
Dissolve 23,4 g of La O (4.7) in 350 mL of deionized water (4.1). Slowly add 50 mL of concentrated nitric
2 3
acid. Stir until solution is completely mixed, transfer to a 1 l volumetric flask, dilute to the mark with water.
DANGER — The addition of the strong acid, HNO , to water liberates a significant amount of heat and
3
can cause a violent reaction.
NOTE The lanthanum solution is used as an ionization suppressant during calcium determination. It is possible to use
other commonly used ionization suppressants, e.g. cesium, as a alternative.
4.9 Magnesium perchlorate, anhydrous, −2,0 mm +0,7 mm, used as a desiccant.
DANGER — Regeneration of magnesium perchlorate by oven drying should not be attempted because
of the risk of explosion. Magnesium perchlorate is a strong oxidant, and should be kept away from
organic materials such as oils, greases and organic solvents.
4.10 Stock solutions
4.10.1 Sodium chloride (NaCl).
4.10.2 Sodium solution, 1 000 mg/L.
Dissolve 2,542 g of sodium chloride (4.10.1) (previously dried at 110 °C for 1 h) in 200 mL of deionized water
(4.1), stir until solution is completely mixed, transfer to a 1 l volumetric flask, dilute to the
...