ISO 11534:2006

Iron ores - Determination of tin - Flame atomic absorption spectrometric method

ISO 11534:2006 specifies a flame atomic absorption spectrometric method for the determination of the mass fraction of tin in iron ores. This method is applicable to mass fractions of tin between 0,001 % and 0,015 % in natural iron ores, iron ore concentrates and agglomerates, including sinter products.

Minerais de fer — Dosage de l'étain — Méthode par spectrométrie d'absorption atomique dans la flamme

General Information

• Status: Published
• Publication Date: 13-Nov-2006
• ICS: 73.060.10 - Iron ores
• Technical Committee: ISO/TC 102/SC 2 - Chemical analysis
• Drafting Committee: ISO/TC 102/SC 2 - Chemical analysis
• Current Stage: 9092 - International Standard to be revised
• Start Date: 08-Oct-2025
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 11534:1998 - Iron ores - Determination of tin content - Flame atomic absorption spectrometric method
• Effective Date: 15-Apr-2008

Overview

ISO 11534:2006 - "Iron ores - Determination of tin - Flame atomic absorption spectrometric method" specifies a validated analytical procedure for measuring tin (Sn) mass fraction in iron ores, concentrates and agglomerates (including sinter). The method applies to tin contents between 0.001 % and 0.015 % and uses flame atomic absorption spectrometry (flame AAS / AAS) after chemical decomposition, fusion and solvent extraction. The standard includes sample preparation, instrumentation requirements, calibration, quality control and precision criteria.

Key topics and technical requirements

• Scope and applicability: Natural iron ores, concentrates and agglomerates; tin range 0.001–0.015 %.
• Sampling and sample prep: Use a laboratory sample of minus 100 µm (or minus 160 µm for ores with significant combined water/oxidizable compounds). Predry samples at 105 °C ± 2 °C (see ISO 7764).
• Decomposition & fusion: Test portion (~2 g) is treated with sulfuric and hydrofluoric acids, heated (muffle furnace 1000–1020 °C), then fused with sodium carbonate / sodium tetraborate flux and dissolved in hydrochloric acid.
• Chemical reduction & extraction: Iron is reduced (ascorbic acid + potassium iodide) and tin is extracted into a TOPO/MIBK organic phase (tri-n-octyl phosphine oxide in methyl isobutyl ketone).
• Flame AAS measurement: Aspirate TOPO/MIBK extract into a dinitrogen oxide/acetylene flame; measure absorbance at 286.3 nm using a tin hollow‑cathode lamp.
• Instrument performance criteria: Minimum sensitivity and linearity requirements for the AAS; stability limits for absorbance (detailed in the standard). Example operational parameters (used as guidelines) include N2O flow ≈ 6.6 L/min and C2H2 ≈ 4.5 L/min.
• Quality control: Run blanks and at least one certified reference material (CRM) in each batch. Perform duplicate independent determinations and follow acceptance/precision procedures (repeatability, between‑laboratory precision) given in the annexes.
• Safety: Handling HF, strong acids and high-temperature fusions requires appropriate laboratory safety controls.

Applications and users

• Who uses it: Analytical laboratories in mining companies, ore processors, independent testing labs, and quality control units that require reliable tin assays in iron ores.
• Practical value: Provides a standardized, reproducible procedure for regulatory compliance, product specification, trade disputes, process control and metallurgical evaluation where low-level tin determination is required.
• Keywords: ISO 11534:2006, tin determination, iron ores, flame AAS, TOPO/MIBK extraction, sample preparation, analytical method.

Related standards

• ISO 3082 - Sampling and sample preparation procedures (iron ores)
• ISO 7764 - Preparation of predried test samples for chemical analysis
• ISO 3696 - Water for analytical laboratory use
• ISO 648 / ISO 1042 - Laboratory glassware specifications

This concise summary helps laboratories and procurement teams understand the method, its technical requirements, and where ISO 11534:2006 fits into mineral analysis workflows.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 11534
Second edition
2006-11-15
Iron ores — Determination of tin — Flame
atomic absorption spectrometric method
Minerais de fer — Dosage de l'étain — Méthode par spectrométrie
d'absorption atomique dans la flamme

Reference number
©
ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
1 Scope. 1
2 Normative references. 1
3 Principle. 1
4 Reagents. 2
5 Apparatus. 3
6 Sampling and samples. 3
6.1 Laboratory sample. 3
6.2 Preparation of predried test samples . 4
7 Procedure. 4
7.1 Number of determinations . 4
7.2 Test portion . 4
7.3 Blank test and check test. 4
7.4 Determination. 4
7.4.1 Decomposition of the test portion . 4
7.4.2 Treatment of the test solution . 5
7.4.3 Adjustment of atomic absorption spectrometer . 5
7.4.4 Atomic absorption measurements. 5
7.4.5 Preparation of calibration solutions . 6
8 Expression of results. 6
8.1 Calculation of mass fraction of tin. 6
8.2 General treatment of results. 6
8.2.1 Repeatability and permissible tolerances. 6
8.2.2 Determination of the analytical result. 7
8.2.3 Between-laboratories precision. 7
8.2.4 Check for trueness . 8
8.2.5 Calculation of final result. 8
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

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 11534 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron,
Subcommittee SC 2, Chemical analysis.
This second edition cancels and replaces the first edition (ISO 11534:1998), which has been technically
revised. It has been updated to alter the manner in which the precision data are presented.

iv © ISO 2006 – All rights reserved

INTERNATIONAL STANDARD ISO 11534:2006(E)

Iron ores — Determination of tin — Flame atomic absorption
spectrometric method
WARNING — This International Standard may 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 tin in iron ores.
This method is applicable to mass fractions of tin between 0,001 % and 0,015 % in natural iron ores, iron ore
concentrates and agglomerates, including sinter products.
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 648: Laboratory glassware — One-mark 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
3 Principle
The test portion is treated with sulfuric acid and hydrofluoric acid in a platinum crucible. The silica is removed
by heating and evaporation. The residue is fused in sodium carbonate/sodium tetraborate flux, and the cooled
melt is dissolved in hydrochloric acid.
Iron is reduced by ascorbic acid and potassium iodide, followed by extraction of tin with tri-n-octyl phosphine
oxide (TOPO) in 4-methyl-2-pentanone (MIBK) solvent.
The tin TOPO/MIBK extract is aspirated into a dinitrogen oxide/acetylene flame and the absorbance of tin is
measured at a 286,3 nm resonance line using a tin hollow-cathode lamp. The absorbance values obtained are
compared with those obtained from calibration solutions.
4 Reagents
During the analysis, use only reagents of recognized analytical reagent grade, and only water that complies
with grade 2 of ISO 3696.
4.1 Sodium carbonate (Na CO ), anhydrous.
2 3
4.2 Sodium tetraborate (Na B O ), anhydrous.
2 4 7
4.3 Iron oxide (Fe O ), of minimum purity 99,9 % (mass fraction) and mass fraction of tin < 0,000 2 %.
2 3
4.4 Hydrochloric acid, ρ 1,16 g/ml to ρ 1,19 g/ml.
4.5 Hydrochloric acid, ρ 1,16 g/ml to ρ 1,19 g/ml, diluted 1 + 1.
4.6 Hydrochloric acid, ρ 1,16 g/ml to ρ 1,19 g/ml, diluted 2 + 3.
Add 200 ml of hydrochloric acid (4.4) to 300 ml of water and mix.
4.7 Hydrofluoric acid, ρ 1,13 g/ml, 40 % (mass fraction) or ρ 1,19 g/ml, 48 % (mass fraction).
4.8 Sulfuric acid, ρ 1,84 g/ml.
4.9 Sulfuric acid, ρ 1,84 g/ml, diluted 1 + 1.
4.10 Ascorbic acid solution, 200 g/l.
This solution shall be prepared freshly on the day of use.
4.11 Potassium iodide/ascorbic acid solution.
Dissolve 90 g of potassium iodide in water, add 30 g of ascorbic acid and 30 ml of hydrochloric acid (4.4), and
dilute with water to 200 ml. This solution shall be freshly prepared just prior to use.
4.12 Tri-n-octyl phosphine oxide (TOPO)/4-methyl-2 pentanone (MIBK) solution.
Dissolve 1 g of TOPO in 100 ml of MIBK.
4.13 Tin standard solution, 200 µg Sn/ml.
Dissolve 0,1 000 g of tin metal [purity > 99,5 % (mass fraction)] in a platinum crucible (with cover) with 5 ml of
hydrochloric acid (4.4). After cooling, transfer the solution to a 500 ml one-mark volumetric flask, add 200 ml
of hydrochloric acid (4.5), and dilute to volume with hydrochloric acid (4.5).
4.14 Tin standard solution, 40 µg Sn/ml.
Transfer 20 ml of tin standard solution (4.13) to a 100 ml one-mark volumetric flask, dilute to volume with
hydrochloric acid (4.5) and mix.
4.15 Tin standard solution, 10 µg Sn/ml.
Transfer 5,0 ml of tin standard solution (4.13) to a 100 ml one-mark volumetric flask, dilute to volume with
hydrochloric acid (4.5) and mix.
2 © ISO 2006 – All rights reserved

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.
5.1 Platinum crucible, of capacity 25 ml to 30 ml.
5.2 Platinum rod.
5.3 Muffle furnace, suitable for heating at 1 000 °C to 1 020 °C.
5.4 Atomic absorption spectrometer, equipped with a dinitrogen oxide/acetylene burner.
WARNING — To avoid possible explosion hazards, follow the manufacturer's instructions for igniting
and extinguishing the dinitrogen oxide/acetylene flame. 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 calibration solution (see 7.4.5) shall be at
least 0,13.
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) for all subsequent measurements.
NOTE Instrument parameters may vary with each instrument. The following parameters were successfully used in
several laboratories and they can be used as guidelines. A dinitrogen oxide/acetylene flame was used.
Hollow cathode lamp, mA 12,5
Wavelength, nm 286,3
Dinitrogen oxide flow rate, l/min 6,6
Acetylene flow rate, l/min 4,5
In systems where the values shown above for gas flow rates do not apply, the ratio of the gas flow rates may still be a
useful guideline.
6 Sampling and samples
6.1 Laboratory sample
For analysis, use a laboratory sample of minus 100 µm particle size which has been taken and prepared in
accordance with ISO 3082. In the case of ores having significant contents of combined water or oxidizable
compounds, use a particle size of minus 160 µm.
NOTE A guideline on significant contents of combined
...