ISO 10203:2015
(Main)Iron ores — Determination of calcium — Flame atomic absorption spectrometric method
Iron ores — Determination of calcium — Flame atomic absorption spectrometric method
ISO 10203:2015 specifies a flame atomic absorption spectrometric method for the determination of the mass fraction of calcium in iron ores. This method is applicable to mass fractions of calcium between 0,010 % and 8,00 % in natural iron ores, iron ore concentrates, and agglomerates, including sinter products.
Minerais de fer — Dosage du calcium — Méthode par spectrométrie d'absorption atomique dans la flamme
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 10203
Third edition
2015-07-01
Iron ores — Determination of
calcium — Flame atomic absorption
spectrometric method
Minerais de fer — Dosage du calcium — Méthode par spectrométrie
d’absorption atomique dans la flamme
Reference number
ISO 10203:2015(E)
©
ISO 2015
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ISO 10203:2015(E)
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ii © ISO 2015 – All rights reserved
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ISO 10203:2015(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Reagents . 1
5 Apparatus . 2
6 Sampling and samples . 3
6.1 Laboratory sample . 3
6.2 Preparation of predried test samples . 3
7 Procedure. 4
7.1 Number of determinations . 4
7.2 Test portion . 4
7.3 Blank test and check test . 4
7.3.1 Blank test . 4
7.3.2 Check test . 4
7.4 Determination . 5
7.4.1 Decomposition of the test portion . 5
7.4.2 Treatment of the residue . 5
7.4.3 Preparation of the test solution . 5
7.4.4 Adjustment of the atomic absorption spectrometer. 6
7.4.5 Atomic absorption measurements . 6
8 Expression of results . 7
8.1 Calculation of mass fraction of calcium . 7
8.2 General treatment of results . 7
8.2.1 Repeatability and permissible tolerance . 7
8.2.2 Determination of analytical result . 8
8.2.3 Between-laboratories precision . 8
8.2.4 Check for trueness . 8
8.2.5 Calculation of final result . 9
8.3 Oxide factor . 9
9 Test report . 9
Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for
test samples .10
Annex B (informative) Derivation of repeatability and permissible tolerance equations .11
Annex C (informative) Precision data obtained by international analytical trials .12
Bibliography .13
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ISO 10203:2015(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.
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
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
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 WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information.
The committee responsible for this document is ISO/TC 102, Iron ore and direct reduced iron, Subcommittee
SC 02, Chemical analysis.
This third edition cancels and replaces the second edition (ISO 10203:2006), which has been
technically revised.
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INTERNATIONAL STANDARD ISO 10203:2015(E)
Iron ores — Determination of calcium — Flame atomic
absorption spectrometric method
WARNING — This International Standard might involve hazardous materials, operations, and
equipment. This International Standard does not purport to address all of the safety problems
associated with its use. It is the responsibility of the user of this International Standard to
establish appropriate health and safety practices and determine the applicability of regulatory
limitations prior to use.
1 Scope
This International Standard specifies a flame atomic absorption spectrometric method for the
determination of the mass fraction of calcium in iron ores.
This method is applicable to mass fractions of calcium between 0,010 % and 8,00 % in natural iron ores,
iron ore concentrates, and agglomerates, including sinter products.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3082, Iron ores — Sampling and sample preparation procedures
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 7764, Iron ores — Preparation of predried test samples for chemical analysis
ISO 80000-1:2009, Quantities and units — Part 1: General
ISO Guide 35, Reference materials — General and statistical principles for certification
3 Principle
The test portion is decomposed by the treatment with hydrochloric acid and a small amount of nitric
acid, and then evaporated to dehydrate silica, followed by dilution and filtration.
The residue is ignited and silica is removed by evaporation with hydrofluoric and sulfuric acids. The
residue is fused with sodium carbonate and the cooled melt is dissolved in the filtrate.
The solution obtained is aspirated into the flame of an atomic absorption spectrometer using a dinitrogen
oxide/acetylene burner.
The absorbance values obtained for calcium are compared with those obtained from calibration solutions.
4 Reagents
During the analysis, use only reagents of recognized analytical grade and only water that complies with
Grade 2 of ISO 3696.
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ISO 10203:2015(E)
4.1 Sodium carbonate, (Na CO ), anhydrous.
2 3
4.2 Hydrofluoric acid, (ρ 1,19 g/ml).
4.3 Hydrochloric acid, ρ 1,19 g/ml, diluted 1 + 9.
4.4 Nitric acid, ρ 1,4 g/ml.
4.5 Hydrofluoric acid, ρ 1,13 g/ml, 40 % (mass fraction) or ρ 1,185 g/ml, 48 % (mass fraction).
4.6 Sulfuric acid, ρ 1,84 g/ml, diluted 1 + 1.
4.7 Pure iron, minimum purity 99,9 % (mass fraction), of mass fraction of calcium less than 0,000 2 %.
4.8 Background solution.
Dissolve 5,0 g pure iron (4.7) in 50 ml of hydrochloric acid (4.2) and oxidize by adding nitric acid (4.4)
drop by drop. Evaporate until a syrupy consistency is obtained. Add 20 ml of hydrochloric acid (4.2)
and dilute to 200 ml with water. Dissolve 17 g of sodium carbonate (4.1) in water, add carefully to the
iron solution, and heat to remove carbon dioxide. Transfer the cooled solution to a 1 000 ml one-mark
volumetric flask, dilute to volume with water, and mix.
4.9 Lanthanum chloride solution.
Dissolve 50 g of lanthanum chloride (LaCl ·7H O) (of mass fraction of calcium less than 0,002 %) in
3 2
50 ml of hydrochloric acid (4.2) and 300 ml of hot water. Cool and dilute to 1 l.
4.10 Calcium standard solution, 25 μg Ca/ml.
Dissolve 1,248 7 g of dried calcium carbonate (CaCO ) [minimum purity 99,9 % (mass fraction), dried
3
at 105 °C for 1 h] in 100 ml of hydrochloric acid (4.2), diluted 1 + 3. When dissolved, cool, transfer to a
1 000 ml one-mark volumetric flask, dilute to volume with water, and mix. Transfer 10 ml of this solution
to a 200 ml one-mark volumetric flask, dilute to volume with water, and mix.
4.11 Calcium calibration solutions.
Using pipettes, transfer 2,0 ml, 5,0 ml, 10,0 ml, 15,0 ml, and 20,0 ml portions of the calcium standard
solutions (4.10) to 200 ml volumetric flasks (see next paragraph). Add 6 ml of hydrochloric acid (4.2),
60 ml of background solution (4.8), and 40 ml of lanthanum chloride solution (4.9) to each flask. Dilute all
the solutions to volume with water and mix. Prepare a zero calcium calibration solution by transferring
60 ml of the background solution to a 200 ml volumetric flask. Then add 6 ml of hydrochloric acid (4.2)
and 40 ml of lanthanum chloride solution (4.9). Dilute all the solutions to volume with water and mix.
5 Apparatus
Ordinary laboratory apparatus, including one-mark pipettes and one-mark volumetric flasks complying
with the specifications of ISO 648 and ISO 1042, respectively, and the following.
All glassware, volumetric flask lids, and the platinum crucibles shall first be washed in hydrochloric
acid (diluted 1 + 1) and then in water.
5.1 Platinum crucible, of minimum capacity 30 ml.
5.2 Muffle furnace, capable of maintaining a temperature of approximately 1 100 °C.
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ISO 10203:2015(E)
5.3 Atomic absorption spectrometer, equipped with a dinitrogen oxide/acetylene burner.
WARNING — Follow the manufacturer’s instructions for igniting and extinguishing the dinitrogen
oxide/acetylene flame to avoid possible explosion hazards. Wear tinted safety glasses whenever
the flame is burning.
The atomic absorption spectrometer used in this method shall meet the following criteria.
a) Minimum sensitivity: the absorbance of the most concentrated calcium calibration solution (see
4.10) shall be at least 0,3.
b) Graph linearity: the slope of the calibration graph covering the top 20 % of the concentration range
(expressed as a change in absorbance) shall not be less than 0,7 of the value of the slope for the
bottom 20 % of the concentration range determined in the same way.
c) Minimum stability: the standard deviation of the absorbance of the most concentrated calibration
solution and that of the zero calibration solution, each being calculated from a sufficient number of
repetitive measurements, shall be less than 1,5 % and 0,5 %, respectively, of the mean value of the
absorbance of the most concentrated calibration solution.
The use of a strip chart recorder and/or digital readout device is recommended to evaluate criteria a),
b), and c) and for all subsequent measurements.
NOTE Instrument parameters can vary with each instrument. The following parameters were successfully
used in several laboratories and they can be used as guidelines. Solutions were aspirated into a dinitrogen
oxide/acetylene flame of a premix burner.
In systems where the values shown below for gas flow rates do not apply, the ratio of the gas flow rates may still
be a useful guideline.
— Hollow cathode lamp, mA 15
— Wavelength, nm 422,7
— Dinitrogen oxide f
...
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