ISO 4689-2:2004

SLOVENSKI STANDARD
SIST ISO 4689-2:2005
01-november-2005
äHOH]RYHUXGH±'RORþHYDQMHåYHSOD±GHO0HWRGDVVHåLJDQMHPWLWUDFLMR
Iron ores -- Determination of sulfur content -- Part 2: Combustion/titration method
Minerais de fer -- Dosage du soufre -- Partie 2: Méthode par combustion et titration
Ta slovenski standard je istoveten z: ISO 4689-2:2004
ICS:
73.060.10 Železove rude Iron ores
SIST ISO 4689-2:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 4689-2:2005

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SIST ISO 4689-2:2005
INTERNATIONAL ISO
STANDARD 4689-2
First edition
2004-04-01
Iron ores — Determination of sulfur
content —
Part 2:
Combustion/titration method
Minerais de fer — Dosage du soufre —
Partie 2: Méthode par combustion et titration

Reference number
ISO 4689-2:2004(E)
©
ISO 2004

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SIST ISO 4689-2:2005
ISO 4689-2:2004(E)
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SIST ISO 4689-2:2005
ISO 4689-2:2004(E)
Contents Page
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Reagents . 1
5 Apparatus . 2
6 Sampling and samples . 4
7 Procedure . 4
8 Expression of results . 6
9 Test report . 8
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 trial . 12
Bibliography . 13
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SIST ISO 4689-2:2005
ISO 4689-2:2004(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 4689-2 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee
SC 2, Chemical analysis.
This first edition, in part cancels and replaces ISO 4690:1986, which has been technically revised.
ISO 4689 consists of the following parts, under the general title Iron ores — Determination of sulfur content:
— Part 2: Combustion/titration method
— Part 3: Combustion/infrared method
The following part is under preparation:
— Part 1: Barium sulfate gravimetric method
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SIST ISO 4689-2:2005
ISO 4689-2:2004(E)
Introduction
This part of ISO4689 was originally published as, ISO4690:1986, Iron ores — Determination of sulfur
content — Combustion method. Under a policy of rationalization of the numbering system used in ISO/TC 102,
it has been decided to re-designate this document as ISO 4689-2. It was further decided to introduce a
combustion/infrared method, numbered ISO 4689-3.
When next revised, ISO 4689:1986, Iron ores — Determination of sulfur content — Barium sulfate gravimetric
method, will be re-designated ISO 4689-1.
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SIST ISO 4689-2:2005
.
vi

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SIST ISO 4689-2:2005
INTERNATIONAL STANDARD ISO 4689-2:2004(E)
Iron ores — Determination of sulfur content —
Part 2:
Combustion/titration method
WARNING — This part of ISO 4689 may involve hazardous materials, operations and equipment. This
part of ISO 4689 does not purport to address all of the safety problems associated with its use. It is the
responsibility of the user of this part of ISO 4689 to establish appropriate health and safety practices
and determine the applicability of regulatory limitations prior to use.
1Scope
This part of ISO 4689 specifies a combustion/titration method for the determination of the sulfur content of iron
ores.
0,002 % 0,25 %
This method is applicable to sulfur contents between (mass fraction) and (mass fraction) in
natural iron ores, iron ore concentrates and agglomerates, including sinter products. The results are not
affected by the presence of fluoride.
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 385-1:1984, Laboratory glassware — Burettes — Part 1: General requirements
ISO 648:1977, Laboratory glassware — One-mark pipettes
ISO 1042:1998, Laboratory glassware — One-mark volumetric flasks
ISO 3082:2000, Iron ores — Sampling and sample preparation procedures
ISO 7764:1985, Iron ores — Preparation of predried test samples for chemical analysis
3 Principle
◦
The sample is mixed with tungsten(VI) oxide and heated at 1 200 C in a resistance furnace, using nitrogen as
a carrier gas.
The evolved sulfur dioxide is absorbed in dilute hydrochloric acid solution containing starch and potassium
iodide, and the solution is titrated continuously during evolution with a standard volumetric solution of potassium
iodate.
4Reagents
During analysis, use only reagents of recognized analytical grade, and only distilled water or water of equivalent
purity.
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SIST ISO 4689-2:2005
ISO 4689-2:2004(E)
4.1 Magnesium perchlorate, Mg(ClO ) , anhydrous, free flowing, particle size 0,5 mm to 2 mm.
4 2
4.2 Tungsten(VI) oxide, (WO ).
3
4.3 Tin(II) chloride, SnCl 2H O, particle size to .
· 0,5 mm 2 mm
2 2
4.4 Soda-asbestos, particle size 0,5 mm to 2 mm.
4.5 Hydrochloric acid, ρ 1,16 g/ml to 1,19 g/ml, diluted 1+ 66.
4.6 Potassium iodide, KI, 3% (mass fraction) solution.
4.7 Starch, 2% (mass fraction) solution.
Make a suspension of 2,0g of starch in 10ml of water, add to 50ml of boiling water and stir. Cool, dilute to
100 ml and mix.
Prepare this solution immediately prior to use.
4.8 Potassium iodate, KIO , standard volumetric solution, 0,001 042 mol/l.
3
◦
NOTE The potassium iodate should be previously dried for 2 h at 130 C.
Weigh, to the nearest 0,000 2 g, 0,223 g of dried potassium iodate and dissolve in water. Cool, transfer to a
1 litre volumetric flask, dilute to volume and mix.
1 ml of this standard volumetric solution is equivalent to 0,10 mg of sulfur.
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 as well as the following. See Figure 1.
5.1 Nitrogen supply.
5.2 Drying tower, containing soda-asbestos (4.4) and magnesium perchlorate (4.1).
5.3 Flowmeter, graduated from 0 to 1 l/min.
◦ ◦
5.4 Resistance furnace, capable of maintaining a temperature of 1 200 C± 25 C.
◦ ◦
5.5 Refractory combustion tube, capable of withstanding a temperature of 1 200 C± 25 C.
5.6 Refractory combustion boat, with loose-fitting lid, or a suitable refractory combustion boat capable of
accommodating a porous cartridge, as shown in Figures 2a) or 2b) respectively. The following dimensions can
be used as guidelines.
Combustion boat Cartridge
Length 80 mm Length 50 mm
Width 13 mm Internal diameter 15 mm
Depth 9mm
5.7 Tin(II) chloride absorption tube, of narrow glass tubing containing approximately 10 g of solid tin(II)
chloride (4.3), suitably plugged with inert wool to prevent the reagent being blown into the absorption vessel. A
U-tube is suitable. Where necessary this is inserted in the train at the exit of the combustion tube at point X in
Figure 1.
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SIST ISO 4689-2:2005
ISO 4689-2:2004(E)
NOTE If the sample is known or thought to contain chloride, e.g., in the form of sodium chloride, chlorapatite or scapolite,
the chlorine formed during combustion of the sample should be removed by passing the gas stream through solid tin(II)
chloride in a suitable tube or vessel (5.7) prior to absorption and titration. If numerous samples having chloride contents
(mass fraction) are to be analysed, it is advisable to determine the absorption capacity of the tin(II) chloride in order
> 1%
to be able to judge the most suitable interval for reagent replacement. In such cases, a larger absorption vessel may be
preferred.
The tin(II) chloride absorption tube should also be fitted if the chloride content of the test sample is unknown.
5.8 Cylinder, 100 ml, tall form, to hold the absorbing solution.
5.9 Bubbler, multi-hole, to reach to the bottom of the cylinder (5.8).
5.10 Burette, conforming to ISO 385-1, graduated in divisions of 0,05 ml.
NOTE For determination of low sulfur contents (< 0,005 % [mass fraction)], alternative titration devices such as a piston
burette or a suitable micro-syringe capable of delivering small, precise aliquots of titrant may be used.
Key
1 soda-asbestos
2 anhydrous magnesium perchlorate
3flowmeter
4 combustion boat
5 resistance furnace
6 multihole bubbler
a
Nitrogen.
Figure 1 — Combustion apparatus
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SIST ISO 4689-2:2005
ISO 4689-2:2004(E)
Dimensions in millimetres
a) with loose-fitting lid
b) with cartridge
Key
1 loose-fitting lid
a
Gas flow.
Figure 2 — Combustion boats
6 Sampling and samples
6.1 Laboratory sample
For analysis, use a laboratory sample of −100µm 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 −160µm.
NOTE A guideline on significant contents of combined water and oxidizable compounds is incorp
...