ISO 2597-2:2008
(Main)Iron ores — Determination of total iron content — Part 2: Titrimetric methods after titanium(III) chloride reduction
Iron ores — Determination of total iron content — Part 2: Titrimetric methods after titanium(III) chloride reduction
ISO 2597-2:2008 specifies two titrimetric methods, free from mercury pollution, for the determination of total iron content in iron ores, using potassium dichromate as titrant after reduction of the iron(III) by tin(II) chloride and titanium(III) chloride. The excess reductant is then oxidized by either dilute potassium dichromate (method 1) or perchloric acid (method 2). Both methods are applicable to a concentration range of 30 % by mass to 72 % by mass of iron in natural iron ores, iron ore concentrates and agglomerates, including sinter products.
Minerais de fer — Dosage du fer total — Partie 2: Méthodes titrimétriques après réduction au chlorure de titane(III)
General Information
Relations
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 2597-2
First edition
2008-11-15
Iron ores — Determination of total iron
content —
Part 2:
Titrimetric methods after titanium(III)
chloride reduction
Minerais de fer — Dosage du fer total —
Partie 2: Méthodes titrimétriques après réduction au chlorure de
titane(III)
Reference number
ISO 2597-2:2008(E)
©
ISO 2008
---------------------- Page: 1 ----------------------
ISO 2597-2:2008(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2008
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2008 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 2597-2:2008(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Principle. 2
3.1 Decomposition of the test portion . 2
3.2 Titration of iron . 2
4 Reagents. 2
5 Apparatus . 4
6 Sampling and samples. 5
6.1 Laboratory sample. 5
6.2 Preparation of test samples. 5
7 Procedure . 5
7.1 Number of determinations . 5
7.2 Blank test and check test. 5
7.3 Determination of hygroscopic moisture content . 6
7.4 Test portion . 6
7.5 Determination. 6
8 Expression of results . 9
8.1 Calculation of total iron content. 9
8.2 General treatment of results. 9
8.3 Oxide factors . 11
9 Test report . 11
Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for test
samples. 12
Annex B (informative) Derivation of precision statements. 13
Annex C (normative) Procedure of the Japanese weighing method . 14
Bibliography . 15
© ISO 2008 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 2597-2:2008(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 2597-2 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron,
Subcommittee SC 2, Chemical analysis.
ISO 2597 consists of the following parts, under the general title Iron ores — Determination of total iron
content:
⎯ Part 1: Titrimetric method after tin(II) chloride reduction
⎯ Part 2: Titrimetric methods after titanium(III) chloride reduction
iv © ISO 2008 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 2597-2:2008(E)
Iron ores — Determination of total iron content —
Part 2:
Titrimetric methods after titanium(III) chloride reduction
1 Scope
This part of ISO 2597 specifies two titrimetric methods, free from mercury pollution, for the determination of
total iron content in iron ores, using potassium dichromate as titrant after reduction of the iron(III) by tin(II)
chloride and titanium(III) chloride. The excess reductant is then oxidized by either dilute potassium dichromate
(method 1) or perchloric acid (method 2).
Both methods are applicable to a concentration range of 30 % mass fraction to 72 % mass fraction of iron in
natural iron ores, iron ore concentrates and agglomerates, including sinter products.
WARNING — This part of ISO 2597 may involve hazardous materials, operations and equipment. This
part of ISO 2597 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 2597 to establish appropriate health and safety practices
and determine the applicability of regulatory limitations prior to use.
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 31-0:1992, Quantities and units — Part 0: General principles
ISO Guide 35, Reference materials — General and statistical principles for certification
ISO 385, Laboratory glassware — Burettes
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 2008 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO 2597-2:2008(E)
3 Principle
3.1 Decomposition of the test portion
3.1.1 Acid decomposition
For samples containing not more than 0,05 % mass fraction of vanadium, the test portion is treated with
hydrochloric acid in the presence of tin chloride and the residue is filtered, ignited and treated with hydrofluoric
and sulfuric acids. The mixture is fused with potassium disulfate and the cold melt is dissolved in water and
hydrochloric acid then neutralized with ammonia solution. The precipitate is filtered, washed in water,
dissolved in hydrochloric acid and combined with the main iron solution, which is treated with potassium
permanganate and evaporated.
3.1.2 Fusion-filtration
For samples containing more than 0,05 % mass fraction of vanadium, the test portion is fused with a mixture
of fluxes, the cold melt is leached with water and the precipitate is filtered, washed in sodium hydroxide
solution, dissolved in hydrochloric acid and evaporated.
3.2 Titration of iron
The major portion of the iron(III) is reduced by tin(II) chloride and the remainder of the iron(III) is reduced by
titanium(III) chloride. The excess reductant is oxidized with either dilute potassium dichromate solution
(method 1) or dilute perchloric acid (method 2). The reduced iron is titrated with potassium dichromate
solution using the sodium diphenylaminesulfonate indicator.
4 Reagents
During the analysis, use only reagents of recognized analytical reagent grade, and only distilled water or water
of equivalent purity.
Method
4.1 Hydrochloric acid, ρ1,16 g/ml to 1,19 g/ml. 1 and 2
4.2 Hydrochloric acid, ρ1,16 g/ml to 1,19 g/ml, diluted 1 + 1. 1 and 2
4.3 Hydrochloric acid, ρ1,16 g/ml to 1,19 g/ml, diluted 1 + 12. 1 and 2
4.4 Hydrochloric acid, ρ1,16 g/ml to 1,19 g/ml, diluted 2 + 100. 1 and 2
4.5 Hydrofluoric acid, 40 % mass fraction (ρ1,13 g/ml) or 48 % mass fraction 1 and 2
(ρ1,19 g/ml).
4.6 Sulfuric acid, ρ1,84 g/ml. 1 and 2
4.7 Sulfuric acid, ρ1,84 g/ml, diluted 1 + 1, carefully pour 1 volume of reagent 4.6 into 1 and 2
1 volume of cold water.
4.8 Orthophosphoric acid, ρ1,7 g/ml. 1 and 2
4.9 Perchloric acid, 72 % mass fraction (ρ1,7 g/ml), diluted 1 + 1. 2
2 © ISO 2008 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 2597-2:2008(E)
Method
4.10 Sulfuric acid–orthophosphoric acid mixture, pour 150 ml of orthophosphoric 1 and 2
acid (4.8) into about 400 ml of water while stirring, add 150 ml of sulfuric acid (4.6), cool
in a water bath, dilute with water to 1 l and mix well.
4.11 Ammonia solution, 28 % mass fraction (ρ 0,90 g/ml) to 30 % mass fraction 1
(ρ 0,96 g/ml).
4.12 Sodium hydroxide (NaOH) solution, 20 g/l. 1 and 2
4.13 Hydrogen peroxide (H O ), 30 % by volume solution. 1 and 2
2 2
4.14 Hydrogen peroxide (H O ), 30 % by volume solution, diluted 1 + 9. 1
2 2
4.15 Tin(II)–hydrochloric acid solution, dissolve 130 g of tin metal in about 500 ml of 1 and 2
hydrochloric acid (4.1) and dilute with hydrochloric acid to 1 l. This solution should be
stored in a brown glass bottle. Use supernatant liquid as needed.
4.16 Tin(II) chloride solution, 100 g/l, dissolve 100 g of crystalline tin(II) chloride 1 and 2
.
(SnCl 2H O) in 200 ml of hydrochloric acid (4.1) by heating the solution in a water bath.
2 2
Cool the solution and dilute with water to 1 l. This solution should be stored in a brown
glass bottle with a small quantity of granular tin metal.
4.17 Potassium permanganate (KMnO ) solution, 25 g/l. 1 and 2
4
4.18 Potassium dichromate (K Cr O ) solution, 1 g/l. 1
2 2 7
4.19 Titanium(III) chloride (TiCl ) solution, 20 g/l, dilute one volume of titanium(III) 1 and 2
3
chloride solution (about 20 % TiCl ) with nine volumes of hydrochloric acid (4.2).
3
Alternatively, dissolve 1,3 g of titanium sponge in about 40 ml of hydrochloric acid (4.1) in
a covered beaker by heating in a water bath. Cool the solution and dilute with water to
200 ml. Prepare fresh solution as needed.
4.20 Potassium disulfate (K S O ), fine powder. 1 and 2
2 2 7
4.21 Flux mixture, mix one portion of anhydrous sodium carbonate (Na CO ) and two 1 and 2
2 3
portions of sodium peroxide (Na O ).
2 2
4.22 Iron standard solution, 0,1 mol/l, transfer 5,58 g of pure iron (purity greater than 1 and 2
99,9 % mass fraction) to a 500 ml Erlenmeyer flask and place a small filter funnel in the
neck. Add 75 ml of hydrochloric acid (4.2) in small increments and heat until dissolved.
Cool and oxidize with 5 ml of hydrogen peroxide (4.13) added in small portions. Heat to
boiling and boil to decompose the excess hydrogen peroxide and to expel chlorine. Cool,
transfer to a 1 000 ml volumetric flask and mix well.
1,00 ml of this solution is equivalent to 1,00 ml of the standard potassium dichromate
solution (4.23).
© ISO 2008 – All rights reserved 3
---------------------- Page: 7 ----------------------
ISO 2597-2:2008(E)
Method
4.23 Potassium dichromate (99,9 % minimum purity), standard solution, 1 and 2
0,016 67 mol/l, pulverize about 6 g of potassium dichromate reagent in an agate mortar,
dry at 140 °C to 150 °C for 2 h, and cool to room temperature in a desiccator.
Transfer 4,903 g of this material to a 300 ml beaker, dissolve in about 100 ml of water,
transfer quantitatively to a 1 000 ml volumetric flask, make up to volume with water after
cooling to 20 °C and mix well. Record the temperature at which this dilution was made
(20 °C) on the stock bottle. Measure the temperature at each use to correct the volume of
titrant used.
NOTE 1 The volumetric flask should previously be calibrated by weighing the mass of water
contained at 20 °C and converting to volume.
NOTE 2 Water used for preparation should previously be equilibrated at room temperature.
NOTE 3 A calibrated mercury thermometer, graduated in 0,1 °C divisions and having a marked
dipping line, should be used. Take a sufficient volume of standard solution for dipping the
thermometer and transfer to a suitable beaker. Measure the temperature of the solution to the
nearest 0,1 °C, after dipping for more than 60 s.
4.24 Indigo carmine [indigo-5,5'-disulfonic acid disodium salt C H O N S Na )] 1
l6 8 8 2 2 2
solution, 0,1 g/100 ml, dissolve 0,1 g of indigo carmine in a cold mixture of 50 ml sulfuric
acid (4.7) and 50 ml of water.
4.25 Sodium diphenylaminesulfonate indicator solution, 0,2 g/100 ml, dissolve 0,2 g 1 and 2
of sodium diphenylaminesulfonate (C H NHC H SO Na) in a small volume of water and
6 5 6 4 3
dilute to 100 ml.
Store the solution in a brown glass bottle.
5 Apparatus
The pipette and volumetric flask specified shall conform with ISO 648 and ISO 1042 respectively.
Ordinary laboratory apparatus, and
5.1 Alumina, zirconium or vitreous carbon crucible, capacity 25 ml to 30 ml, crucibles should be
cleaned before use to avoid contamination with iron.
5.2 Burette, class A, conforming with ISO 385.
5.3 Weighing bottle, of approximate volume 10 ml and approximate mass 6 g.
5.4 Platinum crucible, capacity 25 ml to 30 ml and having a lid.
5.5 Weighing spatula, of a non-magnetic material or demagnetized stainless steel.
5.6 Muffle furnace, suitable for operation in the range 500 °C to 800 °C.
4 © ISO 2008 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 2597-2:2008(E)
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 less than 160 µm.
NOTE 1 A guideline on significant contents of combined water and oxidizable compounds is incorporated in ISO 7764.
NOTE 2 If the determination of total iron relates to a reducibility test, prepare the laboratory sample by crushing and
pulverizing, to less than 100 µm particle size, the whole of one of the reducibility test portions which has been reserved for
chemical analysis. In the case of ores having significant contents of combined water or oxidizable compounds, use a
particle size of less than 160 µm.
6.2 Preparation of test samples
6.2.1 General
Depending on the ore type, proceed in accordance with either 6.2.2 or 6.2.3.
6.2.2 Ores having significant contents of combined water or oxidizable compounds
Prepare an air-equilibrated test sample in accordance with ISO 2596 with the following types of ore:
a) processed ores containing metallic iron;
b) natural or processed ores in which the sulfur content is higher than 0,2 % mass fraction;
c) natural or processed ores in which the content of combined water is higher than 2,5 % mass fraction.
6.2.3 Ores outside the scope of 6.2.2
Prepare a predried test sample as follows.
Thoroughly mix the laboratory sample and, taking multiple increments, extract a test sample in such a manner
that it is representative of the whole contents of the container. Prepare test portions in accordance with the
Japanese weighing method (see Annex C).
7 Procedure
7.1 Number of determinations
Carry out the analysis, at least in duplicate, in accordance with Annex A, independently, on one test sample
(see 6.2).
NOTE The expression “independently” means that the second and any subsequent result(s) is (are) not affected by
the previous result(s). For this particular analytical method, this condition implies that the repetition of the procedure
should be carried out either by the same operator at a different time, or by a different operator, including appropriate
recalibration in either case.
7.2 Blank test and check test
In each run, one blank test and one analysis of a certified reference material of the same type of ore shall be
carried out in parallel with the analysis of the ore sample(s) under the same conditions. A test sample of the
certified reference material shall be prepared in the manner appropriate to the type of ore involved (see 6.2
and NOTE 1 below.)
© ISO 2008 – All rights reserved 5
---------------------- Page: 9 ----------------------
ISO 2597-2:2008(E)
Where the analysis is carried out on several samples at the same time, the blank value may be represented
by one test, provided that the procedure is the same and the reagents used are from the same reagent bottles.
Where the analysis is carried out on several samples of the same type of ore at the same time, the analytical
value of one certified reference material may be used.
NOTE 1
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.