ISO 4689-3:2017

Iron ores — Determination of sulfur content — Part 3: Combustion/infrared method

ISO 4689-3:2017 specifies a combustion/infrared method, using a high-frequency induction furnace, for the determination of the sulfur content of iron ores. This method is applicable to sulfur contents between 0,002 % (mass fraction) and 0,25 % (mass fraction) in natural iron ores, iron ore concentrates and agglomerates, including sinter products. The method is not applicable to iron ores containing more than 1,0 % (mass fraction) of combined water. The apparatus, of which the metal filter is equipped with a heating device, can be applied to iron ores containing less than 3,0 % (mass fraction) of combined water.

Minerais de fer — Dosage du soufre — Partie 3: Méthode par combustion et infrarouge

Železove rude - Določevanje žvepla - 3. del: Metoda s sežiganjem/infrardeča metoda

Ta dokument določa metodo s sežiganjem/infrardečo metodo v visokofrekvenčni indukcijski peči za določevanje vsebnosti žvepla v železovih rudah.
Ta metoda se uporablja za vsebnosti žvepla od 0,002 % (masni delež) do 0,25 % (masni delež) v naravnih železovih rudah, koncentratih železove rude in aglomeratih, vključno s sintranimi izdelki. Ta metoda se ne uporablja za železove rude z vsebnostjo vode več kot 1,0 % (masni delež). Naprave, pri katerih je kovinski filter opremljen z napravo za segrevanje, je mogoče uporabiti za železove rude z vsebnostjo vode manj kot 3,0 % (masni delež).

General Information

• Status: Published
• Publication Date: 01-Mar-2017
• 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: 9093 - International Standard confirmed
• Completion Date: 24-Jun-2022
• Ref Project: SIST ISO 4689-3:2017 - Iron ores - Determination of sulfur content - Part 3: Combustion/infrared method

Relations

• Revises: ISO 4689-3:2015 - Iron ores — Determination of sulfur content — Part 3: Combustion/infrared method
• Effective Date: 13-Aug-2016

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 4689-3
Third edition
2017-03
Iron ores — Determination of sulfur
content —
Part 3:
Combustion/infrared method
Minerais de fer — Dosage du soufre —
Partie 3: Méthode par combustion et infrarouge
Reference number
ISO 4689-3:2017(E)
©
ISO 2017

---------------------- Page: 1 ----------------------
ISO 4689-3:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, 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.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 4689-3:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 2
6 Apparatus . 2
7 Sampling and samples . 5
7.1 Laboratory sample . 5
7.2 Preparation of predried test samples . 5
8 Procedure. 5
8.1 Number of determinations . 5
8.2 Test portion . 5
8.3 Blank test and check test . 5
8.4 Determination . 6
8.5 Preparation of calibration graph . 6
9 Expression of results . 7
9.1 Calculation of sulfur content . 7
9.2 General treatment of results . 7
9.2.1 Repeatability and permissible tolerance . 7
9.2.2 Determination of analytical result . 7
9.2.3 Between-laboratories precision . 8
9.2.4 Check for trueness . 8
9.2.5 Calculation of final result . 9
10 Test report . 9
Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for
test samples .11
Annex B (informative) Derivation of repeatability and permissible tolerance equations .12
Annex C (informative) Precision data obtained by international analytical trial .13
Bibliography .14
© ISO 2017 – All rights reserved iii

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ISO 4689-3:2017(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 voluntary nature of standards, 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: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron,
Subcommittee SC 2, Chemical analysis.
This third edition cancels and replaces the second edition (ISO 4689-3:2015), of which it constitutes a
minor revision, with the following changes:
— “0,001 %” has been inserted before “sulfur” in 5.1;
— in 6.7:
— under “Combustion crucible”, “Length” has been changed to “Height”;
— under “Combustion crucible”, outer diameter has been changed from “10 mm” to “26 mm”;
— under “Combustion crucible”, inner diameter has been changed from “26 mm” to “10 mm”;
— “0,2 g” has been added after “sulfur” in 8.2;
— Formula (7) and the relevant descriptions in 9.2.4 have been modified to harmonize this clause
across all standards for which ISO/TC 102/SC 2 is responsible.
A list of all parts in the ISO 4689 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 4689-3:2017(E)

Introduction
ISO 4689-2 was originally published as ISO 4690:1986. Under a policy of rationalization of the numbering
system used in ISO/TC 102, it has been decided to re-designate ISO 4690:1986 as ISO 4689-2. It was
further decided to introduce a combustion/infrared method, numbered ISO 4689-3, i.e. this document.
When next revised, ISO 4689:1986 will be re-designated as ISO 4689-1.
© ISO 2017 – All rights reserved v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 4689-3:2017(E)
Iron ores — Determination of sulfur content —
Part 3:
Combustion/infrared method
WARNING — This document may involve hazardous materials, operations, and equipment. This
document does not purport to address all of the safety problems associated with its use. It is the
responsibility of the user of this document to establish appropriate health and safety practices
and determine the applicability of regulatory limitations prior to use.
1 Scope
This document specifies a combustion/infrared method, using a high-frequency induction furnace, for
the determination of the sulfur content of iron ores.
This method is applicable to sulfur contents between 0,002 % (mass fraction) and 0,25 % (mass
fraction) in natural iron ores, iron ore concentrates and agglomerates, including sinter products. The
method is not applicable to iron ores containing more than 1,0 % (mass fraction) of combined water.
The apparatus, of which the metal filter is equipped with a heating device, can be applied to iron ores
containing less than 3,0 % (mass fraction) of combined water.
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 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 2596, Iron ores — Determination of hygroscopic moisture in analytical samples — Gravimetric, Karl
Fischer and mass-loss methods
ISO 3082, Iron ores — Sampling and sample preparation procedures
ISO 7764, Iron ores — Preparation of predried test samples for chemical analysis
ISO Guide 35, Reference materials — General and statistical principles for certification
3 Terms and definitions
No terms and definitions are listed 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
© ISO 2017 – All rights reserved 1

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ISO 4689-3:2017(E)

4 Principle
The sample is mixed with a flux containing iron, tin and tungsten and heated in a high-frequency
induction furnace, using oxygen as a supporting fuel and carrier gas.
The evolved sulfur dioxide is carried by oxygen into the cell of an infrared detector, where the
absorption scale is read.
5 Reagents
During analysis, use only reagents of recognized analytical grade, and only distilled water or water of
equivalent purity.
5.1 Metallic iron, particle size 0,2 mm to 1,2 mm containing less than 0,001 % sulfur.
5.2 Magnesium perchlorate, Mg(ClO ) , anhydrous, free flowing, particle size 0,5 mm to 2 mm.
4 2
5.3 Iron(III) oxide, containing less than 0,003 % sulfur.
5.4 Metallic tin, particle size 0,2 mm to 1,2 mm, containing less than 0,001 % sulfur.
5.5 Metallic tungsten, particle size 0,2 mm to 1,2 mm containing less than 0,001 % sulfur.
5.6 Sodium hydroxide coated silica, particle size 0,5 mm to 2 mm.
5.7 Sodium hydroxide, particle size 0,5 mm to 2 mm.
5.8 Standard sulfur solution, prepared as follows.
Dry 8 g of potassium sulfate [purity > 99,99 % (mass fraction)] to constant mass at 105 °C to 110 °C and
cool in a desiccator. Weigh the dried masses of potassium sulfate specified in Table 1 and dissolve each
portion in water. Cool, transfer each portion to separate volumetric flasks and dilute to volume with water.
Table 1 — Sulfur standard solution (calibration series)
Solution no. Mass of potassium sulfate Concentration of sulfur
g mg/ml
1 0,543 5 1,00
2 1,087 0 2,00
3 1,902 2 3,50
4 2,717 4 5,00
6 Apparatus
Ordinary laboratory apparatus, including one-mark pipettes and one-mark volumetric flasks complying
with the specifications of ISO 648 and ISO 1042, respectively, as well as the following. See Figure 1.
6.1 Oxygen supply.
6.2 Absorption tower, containing soda-asbestos (5.6) or sodium hydroxide (5.7).
6.3 Drying tower, containing magnesium perchlorate (5.2).
2 © ISO 2017 – All rights reserved

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ISO 4689-3:2017(E)

6.4 High-frequency induction furnace, having a heating induction coil (height 30 mm to 55 mm, 4 to
5 rolls), capable of heating to a temperature of 1 200 °C.
An example of a combustion furnace, with combustion gas-refining section, is given in Figure 1.
6.5 Combustion tube, quartz.
6.6 Refractory combustion crucible.
Key
1 metal filte
...

SLOVENSKI STANDARD
SIST ISO 4689-3:2017
01-maj-2017
1DGRPHãþD
SIST ISO 4689-3:2016
äHOH]RYHUXGH'RORþHYDQMHåYHSODGHO0HWRGDVVHåLJDQMHPLQIUDUGHþD
PHWRGD
Iron ores - Determination of sulfur content - Part 3: Combustion/infrared method
Minerais de fer - Dosage du soufre - Partie 3: Méthode par combustion et infrarouge
Ta slovenski standard je istoveten z: ISO 4689-3:2017
ICS:
73.060.10 Železove rude Iron ores
SIST ISO 4689-3:2017 en,fr
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 4689-3:2017

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SIST ISO 4689-3:2017
INTERNATIONAL ISO
STANDARD 4689-3
Third edition
2017-03
Iron ores — Determination of sulfur
content —
Part 3:
Combustion/infrared method
Minerais de fer — Dosage du soufre —
Partie 3: Méthode par combustion et infrarouge
Reference number
ISO 4689-3:2017(E)
©
ISO 2017

---------------------- Page: 3 ----------------------

SIST ISO 4689-3:2017
ISO 4689-3:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, 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.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2017 – All rights reserved

---------------------- Page: 4 ----------------------

SIST ISO 4689-3:2017
ISO 4689-3:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 2
6 Apparatus . 2
7 Sampling and samples . 5
7.1 Laboratory sample . 5
7.2 Preparation of predried test samples . 5
8 Procedure. 5
8.1 Number of determinations . 5
8.2 Test portion . 5
8.3 Blank test and check test . 5
8.4 Determination . 6
8.5 Preparation of calibration graph . 6
9 Expression of results . 7
9.1 Calculation of sulfur content . 7
9.2 General treatment of results . 7
9.2.1 Repeatability and permissible tolerance . 7
9.2.2 Determination of analytical result . 7
9.2.3 Between-laboratories precision . 8
9.2.4 Check for trueness . 8
9.2.5 Calculation of final result . 9
10 Test report . 9
Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for
test samples .11
Annex B (informative) Derivation of repeatability and permissible tolerance equations .12
Annex C (informative) Precision data obtained by international analytical trial .13
Bibliography .14
© ISO 2017 – All rights reserved iii

---------------------- Page: 5 ----------------------

SIST ISO 4689-3:2017
ISO 4689-3:2017(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 voluntary nature of standards, 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: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron,
Subcommittee SC 2, Chemical analysis.
This third edition cancels and replaces the second edition (ISO 4689-3:2015), of which it constitutes a
minor revision, with the following changes:
— “0,001 %” has been inserted before “sulfur” in 5.1;
— in 6.7:
— under “Combustion crucible”, “Length” has been changed to “Height”;
— under “Combustion crucible”, outer diameter has been changed from “10 mm” to “26 mm”;
— under “Combustion crucible”, inner diameter has been changed from “26 mm” to “10 mm”;
— “0,2 g” has been added after “sulfur” in 8.2;
— Formula (7) and the relevant descriptions in 9.2.4 have been modified to harmonize this clause
across all standards for which ISO/TC 102/SC 2 is responsible.
A list of all parts in the ISO 4689 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved

---------------------- Page: 6 ----------------------

SIST ISO 4689-3:2017
ISO 4689-3:2017(E)

Introduction
ISO 4689-2 was originally published as ISO 4690:1986. Under a policy of rationalization of the numbering
system used in ISO/TC 102, it has been decided to re-designate ISO 4690:1986 as ISO 4689-2. It was
further decided to introduce a combustion/infrared method, numbered ISO 4689-3, i.e. this document.
When next revised, ISO 4689:1986 will be re-designated as ISO 4689-1.
© ISO 2017 – All rights reserved v

---------------------- Page: 7 ----------------------

SIST ISO 4689-3:2017

---------------------- Page: 8 ----------------------

SIST ISO 4689-3:2017
INTERNATIONAL STANDARD ISO 4689-3:2017(E)
Iron ores — Determination of sulfur content —
Part 3:
Combustion/infrared method
WARNING — This document may involve hazardous materials, operations, and equipment. This
document does not purport to address all of the safety problems associated with its use. It is the
responsibility of the user of this document to establish appropriate health and safety practices
and determine the applicability of regulatory limitations prior to use.
1 Scope
This document specifies a combustion/infrared method, using a high-frequency induction furnace, for
the determination of the sulfur content of iron ores.
This method is applicable to sulfur contents between 0,002 % (mass fraction) and 0,25 % (mass
fraction) in natural iron ores, iron ore concentrates and agglomerates, including sinter products. The
method is not applicable to iron ores containing more than 1,0 % (mass fraction) of combined water.
The apparatus, of which the metal filter is equipped with a heating device, can be applied to iron ores
containing less than 3,0 % (mass fraction) of combined water.
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 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 2596, Iron ores — Determination of hygroscopic moisture in analytical samples — Gravimetric, Karl
Fischer and mass-loss methods
ISO 3082, Iron ores — Sampling and sample preparation procedures
ISO 7764, Iron ores — Preparation of predried test samples for chemical analysis
ISO Guide 35, Reference materials — General and statistical principles for certification
3 Terms and definitions
No terms and definitions are listed 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
© ISO 2017 – All rights reserved 1

---------------------- Page: 9 ----------------------

SIST ISO 4689-3:2017
ISO 4689-3:2017(E)

4 Principle
The sample is mixed with a flux containing iron, tin and tungsten and heated in a high-frequency
induction furnace, using oxygen as a supporting fuel and carrier gas.
The evolved sulfur dioxide is carried by oxygen into the cell of an infrared detector, where the
absorption scale is read.
5 Reagents
During analysis, use only reagents of recognized analytical grade, and only distilled water or water of
equivalent purity.
5.1 Metallic iron, particle size 0,2 mm to 1,2 mm containing less than 0,001 % sulfur.
5.2 Magnesium perchlorate, Mg(ClO ) , anhydrous, free flowing, particle size 0,5 mm to 2 mm.
4 2
5.3 Iron(III) oxide, containing less than 0,003 % sulfur.
5.4 Metallic tin, particle size 0,2 mm to 1,2 mm, containing less than 0,001 % sulfur.
5.5 Metallic tungsten, particle size 0,2 mm to 1,2 mm containing less than 0,001 % sulfur.
5.6 Sodium hydroxide coated silica, particle size 0,5 mm to 2 mm.
5.7 Sodium hydroxide, particle size 0,5 mm to 2 mm.
5.8 Standard sulfur solution, prepared as follows.
Dry 8 g of potassium sulfate [purity > 99,99 % (mass fraction)] to constant mass at 105 °C to 110 °C and
cool in a desiccator. Weigh the dried masses of potassium sulfate specified in Table 1 and dissolve each
portion in water. Cool, transfer each portion to separate volumetric flasks and dilute to volume with water.
Table 1 — Sulfur standard solution (calibration series)
Solution no. Mass of potassium sulfate Concentration of sulfur
g mg/ml
1 0,543 5 1,00
2 1,087 0 2,00
3 1,902 2 3,50
4 2,717 4 5,00
6 Apparatus
Ordinary laboratory apparatus, including one-mark pipettes and one-mark volumetric flasks complying
with the specifications of ISO 648 and ISO 1042, respectively, as well as the following. See Figure 1.
6.1 Oxygen supply.
6.2 Absorption tower, containing soda-asbestos (5.6) or sodium hydroxide (5.7).
6.3 Drying tower, containing magnesium perchlorate (5.2).
2 © ISO 2017 – All rights reserved

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