ISO 2598-1:1992
(Main)Iron ores — Determination of silicon content — Part 1: Gravimetric methods
Iron ores — Determination of silicon content — Part 1: Gravimetric methods
The method is based on decomposition of the test portion by 1) sintering with sodium peroxide and treatment with hydrochloric and perchloric acids and treatment with dilute nitric acid, or 2) treatment with hydrochloric, nitric and perchloric acids, evaporation, filtration of silica with any residue, fusion with sodium carbonate and dissolution in hydrochloric and perchloric acids, in both cases evaporation of the solution, filtration of the precipitated silica, ignition, and weighing, treatment of the ignited residue with hydrofluoric and sulfuric acid, ignition, and reweighing. Applies to silicon contents between 1 % and 15 % in natural iron ores, iron ore concentrates and agglomerates, including sinter products.
Minerais de fer — Dosage du silicium — Partie 1: Méthodes gravimétriques
Železove rude – Določevanje silicija – 1. del: Gravimetrijska metoda
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-1998
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Iron ores -- Determination of silicon content -- Part 1: Gravimetric methods
Minerais de fer -- Dosage du silicium -- Partie 1: Méthodes gravimétriques
Ta slovenski standard je istoveten z: ISO 2598-1:1992
ICS:
73.060.10 Železove rude Iron ores
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
ISO
INTERNATIONAL
STANDARD
First edi tion
19924 2-15
Iron ores - Determination of silicon content -
Part 1:
Gravimetric methods
Minerais de fer - Uosage du silicium -
Partie 1: Methodes gravimetriques
Reference number
ISO 25984 : 1992( E)
ISO 2598=1:1992(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. Esch 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, govern-
mental 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.
Draf? International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an Inter-
national Standard requires approval by at least 75 Yö of the member
bodies casting a vote.
International Standard ISO 2598-1 was prepared by Technical Committee
ISO/TC 102, Iran ores, Sub-Committee SC 2, Chemical analysis.
This part of ISO 2598 cancels and replaces ISO 2598:1980, of which it
constitutes a technical revision.
ISO 2598 consists of the following Parts, under the general title Iran
ores - Determination of silicon content:
- Part 1: Gravimetric methods
- Part 2: Reduced molybdosilicate spectrophotometric method
Annex A forms an integral part of this part of ISO 2598. Annexes B and
C are for information only.
0 ISO 1992
All rights reserved. No part of this publication may be reproduced or utilized in any form
or by any means, electronie or mechanical, including photocopying and microfilm, without
Permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Gen&ve 20 l Switzerland
Printed in Switzerland
ii
ISO 25984 :1992(E)
INTERNATIONAL STANDARD
Iron ores - Determination of silicon content -
Part 1:
Gravimetric methods
ISO 648:1977, Laboratory glassware - One-mark
1 Scope
pipettes.
This patt of ISO 2598 specifies two gravimetric
ISO 1042:1983, Laboratory glassware - One-mark
methods for the determination of the Silicon content
volumetric f7asks.
of iron ores.
ISO 2596:1984, Iran ores - Determination of
These methods are applicable, with certain Iimita-
hygroscopic moisture in analytical samples -
tions, to Silicon contents between 1 % (m/m) and
Gravimetric and Karl Fischer methods.
15 % (m/m) in natura1 iron ores, iron ore concen-
trates and agglomerates, including Sinter products.
ISO 3081:1986, Iran ores - Increment sampling -
Method 1 is not applicable to iron ores having a
Manual method.
content of reducing agents greater than 2 % (m/m),
for instance Pyrite, or to ores having a fluorine con-
ISO 3082:1987, Iran ores - lncrement sampling and
tent greater than 0,l % (m/m). lt is recommended
Sample preparation - Mechanical method.
for lower grade ores having a high content of am-
photeric elements.
ISO 3083:1986, Iran ores - Preparation of samples
- Manual method.
Method 2 tan be used for ores having a fluorine
lt is rec-
content greater than 0,l % (m/m).
ISO 776411985, Iran or-es - Preparation of predried
ommended for high grade ores having a low content
test samples for Chemical analysis.
of gangue.
NOTE 1 For ores having a silicon content less than
5 % @/WZ), the method specified in ISO 2598-2: -11, Iran
3 Principle
ores - Determination of Silicon content - Part 2: Reduced
moiybdosilicate spectrophotometric method, is preferable.
of the test portion, by either
Decomposition
method 1 or method 2.
2 Normative references
Method 1: Decomposition by sintering with sodium
The following Standards contain provisions which,
Peroxide, followed by treatment with hydrochloric
through reference in this text, constitute provisions
and perchloric acids, or
of this part of ISO 2598. At the time of publication,
treatment with
the editions indicated were valid. All Standards are Method 2: Decomposition by
subject to revision, and Parties to agreements based hydrochloric, nitric and perchloric acids (with in-
on this part of ISO 2598 are encouraged to investi- clusion of boric acid, if necessary) and evaporation
to fumes of perchloric acid. Filtration of silica to-
gate the possibility of applying the most recent edi-
gether with any residue, fusion with sodium
tions of the Standards indicated below. Members of
IEC and ISO maintain registers of currently valid carbonate and dissolution in hydrochloric and
perchloric acids.
International Standards.
1) To be published. (At present published as ISO 4686:1980.)
ISO 2598-1 :1992(E)
Evaporation of the Solution from either method 1 or
6 Sampling and samples
method 2 to fumes of perchloric acid and filtration
of the precipitated silica. Ignition of the impure silica
6.1 Laboratory Sample
and weighing. Treatment of the ignited residue with
hydrofluoric and sulfuric acids, followed by ignition
For analysis, use a laboratory Sample of minus
and reweighing.
100 pm particle size which has been taken in ac-
cordante with ISO 3081 or ISO 3082 and prepared in
4 Reagents
accordance with ISO 3082 or ISO 3083. In the case
of ores having significant contents of combined wa-
During the analysis, use only reagents of recognized ter or oxidizable compounds, use a particle size of
analytical grade and only distilled water or water of minus 160 Pm.
equivalent purity.
NOTE 2 A guideline on significant contents of combined
water and oxidizable compounds is incorporated in
4.1 Sodium peroxide (Na,O,), powder.
ISO 7764.
4.2 Boric acid (H,B03).
6.2 Preparation of test samples
To be used as in note 7.
Depending on the ore type, proceed in accordance
with either 6.2.1 or 6.2.2.
4.3 Sodium carbonate (Na,CO,), anhydrous.
6.2.1 Ores having significant quantities of
4.4 Hydrochlorit acid, p IJ6 g/ml to IJ9 g/ml.
combined water or oxidizable compounds and silica
contents above 10 % (m/m)
4.5 Hydrochlorit acid, p 1,16 g/ml to 1,19 g/ml, di-
luted 1 + 1.
Where the silica content is above 10 % (m/m), pre-
pare an air-equilibrated test Sample in accordance
4.6 Hydrochlorit acid, p 1,16 g/ml to IJ9 g/ml, di-
with ISO 2596 for the following types of ores:
luted 1 + 9.
a) processed ores containing metallic iron;
4.7 Perchlorit acid, p 1,67 g/ml, 70 % (fn/m), or
b) natura1 or processed ores in which the Sulfur
p 1,54 g/ml, 60 % @z/m).
content is higher than 0,2 % (m/m);
4.8 Sulfuric acid, E) 1,84 g/ml, diluted 1 + 1.
c) natura1 or processed ores in which the content
of combined water is higher than 2,5 % (m/m).
4.9 Sulfuric acid, p 1,84 g/ml, diluted 1 + 9.
6.22 Ores outside the scope of 6.2.1
4.10 Hydrofluoric acid, p 1,13 g/ml, 40 % (m/r@, or
p 1,185 g/ml, 48 % (m/m).
Prepare a predried test Sample as follows:
Thoroughly mix the laboratory Sample and, taking
4.11 Nitrit acid, p 1,4 g/ml.
multiple increments, extract a test Sample in such a
manner that it is representative of the whole con-
5 Apparatus
tents of the Container. Dry the test Sample at
105 “C + 2 “C as specified in ISO 7764. (This is the
Ordinary laboratory apparatus, including one-mark
predried test Sample.)
pipettes and one-mark volumetric flasks complying
with the specifications of ISO 648 or ISO 1042 re-
spectively, and
7 Procedure
5.1 Nickel, zirconium or vitreous carbon crucibles,
7.1 Number of determinations
of capacity approximately 40 ml.
Carry out the analysis at least in duplicate in ac-
5.2 Platinum crucibles, of capacity approximately cordante with annex A, independently, on one test
40 ml. Sample.
NOTE 3 The expression “independently” means that the
5.3 Nickel spatula.
second and any subsequent result is not affected by the
previous result(s). For this particular analytical method,
5.4 Muffle furnaces, adjustable to 400 “C - + 20 “C this condition implies that the repetition of the procedure
is carried out either by the same Operator at a different
and to temperatures up to 1 050 “C.
ISO 2598=1:1992(E)
Operator including, in either case,
time or a different Place the crucible in the entrance of the muffle fur-
bY
iate recalibrati on.
nace (5.4), set at 400 “C + 20 “C, and leave for
appropr
1 min to 2 min. Place the crucible in the furnace,
maintained at the Same temperature, and leave for
7.2 Test Portion
1 h. Remove the crucible from the furnace and allow
to cool in a desiccator.
Taking several increments, weigh, to the nearest
0,000 2 g, approximately the amount of the predried
NOTE 6 The mixture should not resch the melting Point.
test Sample indicated in table 1.
Should this happen, it is recommended that the Operation
be repeated at a lower temperature.
- Mass of test portion
Table 1
WARNING - Protective goggles should be worn
Si content Mass of test Portion
during the following Operation.
% (mpn) g
Transfer the crucible containing the sintered mass
1 to10
to a 600 ml low-form beaker. Cover the beaker with
10 to 15
a watch-glass and carefully add 200 ml of water. Add
50 ml of hydrochloric acid (4.4) and 25 ml of
perchloric acid (4.7) to dissolve the sintered mass.
NOTE 4 The test portion should be taken and weighed
Remove the crucible from the beaker and rinse it
quickly to avoid reabsorption of moisture.
with hydrochloric acid (4.6) and water. Scrape out
the rest of the sintered mixture adhering to the Walls
7.3 Blank test and check test
of the crucible, using a rubber-tipped glass rod.
Place the beaker on a hot-plate and heat the sol-
In each run, one blank test and one analysis of a
ution gently to decompose the sintered products
certified reference material of the Same type of ore
completely.
shall be carried out in parallel with the analysis of
the ore Sample(s) under the Same conditions. A
Add 1 ml of sulfuric acid (4.9) to prevent precipi-
predried test Sample of the certified reference ma-
tation of titanium.
terial shall be prepared as specified in 6.2.2.
Partially uncover the beaker and heat until dense
white fumes of perchloric acid appear. Cover the
NOTE 5 The certified reference material should be of
the same type as the Sample to be analysed and the
beaker completely and continue heating until there
proper-Ges of the two materials should be sufficiently
are no more fumes in the beaker. Maintain this
similar to ensure that in either case no significant changes
Stage until most of the perchloric acid has evapor-
in the analytical procedure will become necessary.
ated, but avoid evaporation to dryness.
When the analysis is carried out on several samples
Allow the Solution to cool, then add about 25 ml of
at the Same time, the blank value may be represen-
hydrochloric acid (4.5). Agitate and heat gently to
ted by one test, provided that the procedure is the
dissolve the soluble salts. Allow the precipitate to
Same and that the reagents used are from the Same
settle for several minutes, then rinse the Walls of the
reagent bottles.
beaker with about 30 ml of water. Continue immedi-
ately, in accordance with 7.4.2.
When the analysis is carried out on several samples
of the Same type of ore at the Same time, the ana-
lytical value of one certified reference material may
7.4.1.2 Acld attack (Method 2)
be used.
Place the test Portion (7.2) in a 400 ml low-form
beaker and moisten with 5 ml of water.
7.4 Determination
NOTE 7 For ores having fluorine contents greater than
7.4.1 Decomposition of the test Portion
0,l % (m/m) or where the fluorine content is unknown,
0,8 g if boric acid (4.2) should be added to the beaker
If the decomposition is to be based on alkali
containing the test Portion before the addition of 5 ml of
sintering, proceed as specified in 7.4.1.1; if it is to
water.
be based on acid attack, proceed as specified in
7.4.1.2.
Add 50 ml of hydrochloric acid (4.4). Cover the
beaker with a watch-glass and heat gently without
7.4.1.1 Alkali sinter attack (Method 1)
boiling, until decomposition of the test portion is
complete. Add 1 ml of nitric acid (4.11) and then
Place the test Portion (7.2) in a nickel, zirconium or
25 ml of perchloric acid (4.7).
vitreous carbon crucible (5.1), add 3 g of sodium
Add 1 ml of sulfuric acid (4.9) to prevent precipi-
peroxide (4.1), mix thoroughly using the nicke1
spatula (5.3) and tamp the mixture. tation of titanium.
ISO 25984:1992(E)
Partially uncover the beaker and heat until dense Allow the solution to cool, then add about 25 ml sf
white fumes of perchloric acid appear. Cover the hydrochloric acid (4.5). Agitate and heat gently to
beaker completely and continue heating until there dissolve Zhe soluble salts. Allow the precipitate to
are no more fumes in the beaker. Maintain this settle for several minutes, then rinse the Walls of the
Stage until most of the perchloric acid has evapor- beaker with about 30 ml of water. Continue immedi-
ated, but avoid evaporation to dryness. ately, in accordance with 7.4.2.
Allow the Solution to cool, then add about 25 ml of
7.4.2 Treatment of silica
hydrochloric acid (4.5). Agitate and heat gently to
dissolve the soluble salts. Add about 30 ml of water,
Filter the solution containing the insoluble silica ob-
mix and collect the precipitate on a close-texture
tained as in 7.4.1.1 or 7.4.1.2 through a close-texture
filter Paper containing small pieces of filter Paper
filter Paper containing small pieces of filter Paper
or a small amount of filter pulp.
or a small amount of filter pulp. Rinse the beaker
wifh water, and rub the Walls of the beaker using a
Rinse the beaker with water, and rub the Walls of the
...
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