SIST EN ISO 21079-2:2008

Chemical analysis of refractories containing alumina, zirconia, and silica - Refractories containing 5 percent to 45 percent of ZrO2 (alternative to the X-ray fluorescence method) - Part 2: Wet chemical analysis (ISO 21079-2:2008)

This set of standards will give methods for the chemical analysis of AZS (alumina, zirconia, and silica) refractory products and raw materials, using traditional ("wet") methods, ICP-AE spectrometry and FAA spectrometry

Chemische Analyse von aluminiumoxid-, zirkoniumoxid- und silicium(IV)-oxidhaltigen feuerfesten Erzeugnissen - Feuerfeste Erzeugnisse mit einem Massenanteil an ZrO2 von 5 % bis 45 % (Alternative zum Röntgenfluoreszenzverfahren) - Teil 2: Nasschemische Analyse (ISO 21079-2:2008)

Dieser Teil von ISO 21079 legt chemische Analysenverfahren für feuerfeste Erzeugnisse und Rohstoffe (mit 5 % bis 45 % ZrO2) fest, die AZS (Aluminiumoxid, Zirkoniumoxid und Silicium(IV) oxid) enthalten, indem traditionelle (nasschemische) Verfahren, angewendet werden.
Dieser Teil von ISO 21079 gilt nicht für feuerfeste Erzeugnisse, die auf MgO basieren.
Dieser Teil von ISO 21079 stellt eine Alternative zum Röntgenfluoreszenzverfahren (RFA) nach ISO 12677 dar.

Analyse chimique des matériaux réfractaires contenant de l'alumine, de la zircone et de la silice - Matériaux réfractaires contenant de 5 % à 45 % de ZrO2 (méthode alternative à la méthode par fluorescence de rayons X) - Partie 2: Analyse chimique par voie humide (ISO21079-2:2008)

L'ISO 21079-2:2008 spécifie des méthodes d'analyse chimique des matières premières et produits réfractaires AZS (alumine, zircone et silice), contenant de 5 % à 45 % de ZrO2 (zircone), à l'aide des méthodes classiques («par voie humide»).
L'ISO 21079-2:2008 n'est pas applicable aux matériaux réfractaires à base de MgO.
L'ISO 21079:2008 fournit des méthodes alternatives à la méthode d'analyse par fluorescence de rayons X, spécifiée dans l'ISO 12677.

Kemijska analiza ognjevzdržnih izdelkov, ki vsebujejo aluminijev oksid, cirkonijev oksid in silicijev oksid - Ognevzdržni izdelki vsebujejo 5 % do 45 % ZrO2 (alternativa rentgenski fluorescenčni metodi) - 2. del: Mokra kemijska analiza (ISO 21079-2:2008)

General Information

• Status: Published
• Publication Date: 03-Aug-2008
• ICS: 71.040.40 - Chemical analysis
• ICS: 81.080 - Refractories
• Technical Committee: IKER - Ceramics
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 07-May-2008
• Due Date: 12-Jul-2008
• Completion Date: 04-Aug-2008
• Ref Project: EN ISO 21079-2:2008 - Chemical analysis of refractories containing alumina, zirconia, and silica - Refractories containing 5 percent to 45 percent of ZrO2 (alternative to the X-ray fluorescence method) - Part 2: Wet chemical analysis (ISO 21079-2:2008)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 21079-2:2008
01-september-2008
.HPLMVNDDQDOL]DRJQMHY]GUåQLKL]GHONRYNLYVHEXMHMRDOXPLQLMHYRNVLGFLUNRQLMHY
RNVLGLQVLOLFLMHYRNVLG2JQHY]GUåQLL]GHONLYVHEXMHMRGR=U2
DOWHUQDWLYDUHQWJHQVNLIOXRUHVFHQþQLPHWRGLGHO0RNUDNHPLMVNDDQDOL]D,62

Chemical analysis of refractories containing alumina, zirconia, and silica - Refractories
containing 5 percent to 45 percent of ZrO2 (alternative to the X-ray fluorescence method)
- Part 2: Wet chemical analysis (ISO 21079-2:2008)
Chemische Analyse von aluminiumoxid-, zirkoniumoxid- und silicium(IV)-oxidhaltigen
feuerfesten Erzeugnissen - Feuerfeste Erzeugnisse mit einem Massenanteil an ZrO2 von
5 % bis 45 % (Alternative zum Röntgenfluoreszenzverfahren) - Teil 2: Nasschemische
Analyse (ISO 21079-2:2008)
Analyse chimique des matériaux réfractaires contenant de l'alumine, de la zircone et de
la silice - Matériaux réfractaires contenant de 5 % à 45 % de ZrO2 (méthode alternative
à la méthode par fluorescence de rayons X) - Partie 2: Analyse chimique par voie
humide (ISO21079-2:2008)
Ta slovenski standard je istoveten z: EN ISO 21079-2:2008
ICS:
71.040.40 Kemijska analiza Chemical analysis
81.080 Ognjevzdržni materiali Refractories
SIST EN ISO 21079-2:2008 en,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST EN ISO 21079-2:2008

---------------------- Page: 2 ----------------------

SIST EN ISO 21079-2:2008
EUROPEAN STANDARD
EN ISO 21079-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2008
ICS 81.080; 71.040.40

English Version
Chemical analysis of refractories containing alumina, zirconia,
and silica - Refractories containing 5 percent to 45 percent of
ZrO2 (alternative to the X-ray fluorescence method) - Part 2:
Wet chemical analysis (ISO 21079-2:2008)
Analyse chimique des matériaux réfractaires contenant de Chemische Analyse von aluminiumoxid-, zirkoniumoxid-
l'alumine, de la zircone et de la silice - Matériaux und silicium(IV)-oxidhaltigen feuerfesten Erzeugnissen -
réfractaires contenant de 5 % à 45 % de ZrO2 (méthode Feuerfeste Erzeugnisse mit einem Massenanteil an ZrO2
alternative à la méthode par fluorescence de rayons X) - von 5 % bis 45 % (Alternative zum
Partie 2: Méthodes d'analyse chimique par voie humide Röntgenfluoreszenzverfahren) - Teil 2: Nasschemische
(ISO 21079-2:2008) Analyse (ISO 21079-2:2008)
This European Standard was approved by CEN on 12 April 2008.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2008 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21079-2:2008: E
worldwide for CEN national Members.

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

SIST EN ISO 21079-2:2008
EN ISO 21079-2:2008 (E)
Contents Page
Foreword.3

2

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

SIST EN ISO 21079-2:2008
EN ISO 21079-2:2008 (E)
Foreword
This document (EN ISO 21079-2:2008) has been prepared by Technical Committee ISO/TC 33 "Refractories"
in collaboration with Technical Committee CEN/TC 187 “Refractory products and materials” the secretariat of
which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by October 2008, and conflicting national standards shall be withdrawn at
the latest by October 2008.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 21079-2:2008 has been approved by CEN as a EN ISO 21079-2:2008 without any
modification.


3

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

SIST EN ISO 21079-2:2008

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

SIST EN ISO 21079-2:2008

INTERNATIONAL ISO
STANDARD 21079-2
First edition
2008-04-15

Chemical analysis of refractories
containing alumina, zirconia, and silica —
Refractories containing 5 % to 45 %
of ZrO (alternative to the X-ray
2
fluorescence method) —
Part 2:
Wet chemical analysis
Analyse chimique des matériaux réfractaires contenant de l'alumine,
de la zircone et de la silice — Matériaux réfractaires contenant de 5 %
à 45 % de ZrO (méthode alternative à la méthode par fluorescence
2
de rayons X) —
Partie 2: Méthodes d'analyse chimique par voie humide




Reference number
ISO 21079-2:2008(E)
©
ISO 2008

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

SIST EN ISO 21079-2:2008
ISO 21079-2:2008(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 [e-mail]
Web www.iso.org
Published in Switzerland

ii © ISO 2008 – All rights reserved

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

SIST EN ISO 21079-2:2008
ISO 21079-2:2008(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Determination of silicon(IV) oxide. 2
4 Determination of aluminium oxide. 4
5 Determination of iron(III) oxide. 7
6 Determination of titanium(IV) oxide . 8
7 Determination of calcium oxide . 11
8 Determination of magnesium oxide. 12
9 Determination of sodium oxide by flame photometry . 13
10 Determination of potassium oxide by flame photometry . 14
11 Determination of chromium(III) oxide using diphenylcarbazide. 15
12 Determination of zirconium oxide (including hafnium oxide) by mandelic acid
(α-hydroxybenzeneacetic acid) gravimetric method. 16
13 Calculation and expression of test results .17
14 Test report . 17
Bibliography . 18

© ISO 2008 – All rights reserved iii

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

SIST EN ISO 21079-2:2008
ISO 21079-2:2008(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 21079-2 was prepared by Technical Committee ISO/TC 33, Refractories.
ISO 21079 consists of the following parts, under the general title Chemical analysis of refractories containing
alumina, zirconia, and silica — Refractories containing 5 % to 45 % of ZrO (alternative to the X-ray
2
fluorescence method):
⎯ Part 1: Apparatus, reagents and dissolution
⎯ Part 2: Wet chemical analysis
⎯ Part 3: Flame atomic absorption spectrophotometry (FAAS) and inductively coupled plasma emission
spectrometry (ICP-AES)

iv © ISO 2008 – All rights reserved

---------------------- Page: 10 ----------------------

SIST EN ISO 21079-2:2008
INTERNATIONAL STANDARD ISO 21079-2:2008(E)

Chemical analysis of refractories containing alumina, zirconia,
and silica — Refractories containing 5 % to 45 % of ZrO
2
(alternative to the X-ray fluorescence method) —
Part 2:
Wet chemical analysis
1 Scope
This part of ISO 21079 specifies methods for the chemical analysis of AZS (alumina, zirconia, and silica)
refractory products (containing 5 % to 45 % of ZrO ) and raw materials, using traditional (“wet”) methods.
2
This part of ISO 21079 is not applicable to MgO-based refractories.
This part of ISO 21079 gives alternatives to the X-ray fluorescence (XRF) method given in ISO 12677.
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.
1)
ISO 10058-2:— , Chemical analysis of magnesite and dolomite refractory products (alternative to the X-ray
fluorescence method) — Part 2: Wet chemical analysis
ISO 21079-1:2008, Chemical analysis of refractories containing alumina, zirconia and silica — Refractories
containing 5 % to 45 % of ZrO (alternative to the X-ray fluorescence method) — Part 1: Apparatus, reagents
2
and dissolution
ISO 21079-3:2008, Chemical analysis of refractories containing alumina, zirconia and silica — Refractories
containing 5 % to 45 % of ZrO (alternative to the X-ray fluorescence method) — Part 3: Flame atomic
2
absorption spectrophotometry (FAAS) and inductively coupled plasma emission spectrometry (ICP-AES)
ISO 21587-2:2007, Chemical analysis of aluminosilicate refractory products (alternative to the X-ray
fluorescence method) — Part 2: Wet chemical analysis
ISO 26845:2008, Chemical analysis of refractories — General requirements for wet chemical analysis, atomic
absorption spectrometry (AAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES)
methods

1) To be published.
© ISO 2008 – All rights reserved 1

---------------------- Page: 11 ----------------------

SIST EN ISO 21079-2:2008
ISO 21079-2:2008(E)
3 Determination of silicon(IV) oxide
3.1 General
The determination of silicon(IV) oxide is carried out using one of the following methods.
a) Combined use of the dehydration or the coagulation and molybdenum blue methods. This method is
applied to samples consisting of more than 4 % by mass of silicon(IV) oxide.
b) Molybdenum blue method. This method is applied to samples consisting of less than 8 % by mass of
silicon(IV) oxide.
3.2 Combined use of dehydration or coagulation and molybdenum blue methods
3.2.1 Principle
An aliquot portion of stock solution (S1) or (S’1) is treated with ammonium molybdate and the silicomolybdate
is reduced to yield molybdenum blue, the absorbance of which is measured.
The sum of this residual silicon(IV) oxide in solution plus the mass of silicon(IV) oxide (m – m ) derived in
1 2
accordance with 9.2.2.3 or 9.2.3.3 of ISO 21079-1:2008 gives the total silicon(IV) oxide content.
3.2.2 Procedure
This determination should be commenced with little delay after the stock solution (S1) or (S’1) is prepared, as
prolonged standing could allow polymerization of silica to occur leading to low results.
Transfer a 10,0 ml aliquot portion of stock solution (S1) or (S’1) (see Annex A of ISO 21079-1:2008) to a
100 ml plastic beaker, add 2 ml of hydrofluoric acid (1+9), mix with a plastic rod and allow to stand for 10 min.
Add 50 ml of boric acid solution, 2 ml of ammonium molybdate solution while swirling at a temperature of
about 25 °C, and allow to stand for 10 min. Add 5 ml of L (+)-tartaric acid solution while swirling and after
1 min add 2 ml of L (+)-ascorbic acid solution while shaking. Transfer a solution to a 100 ml plastics volumetric
flask, dilute to the mark with water and allow to stand for 60 min.
Measure the absorbance of the solution in a 10 mm cell at a wavelength of 650 nm using water as reference.
3.2.3 Plotting the calibration graph
Transfer 0 ml, 2 ml, 4 ml, 6 ml, 8 ml and 10 ml aliquot portions of diluted silicon(IV) oxide solution (0 mg to
0,4 mg as silicon(IV) oxide) into six 100 ml plastic beakers and, to each, add 10 ml of blank solution (B1) or
(B’1) (see Annex A of ISO 21079-1:2008). Treat these solutions and measure the absorbance as described in
3.2.2, and plot the absorbances against the amounts of silicon(IV) oxide. Prepare the calibration graph by
adjusting the curve so that it passes through the point of origin.
3.2.4 Calculation
Calculate the mass fraction of silicon(IV) oxide, w(SiO ), expressed as a percentage, using Equation (1) with
2
the absorbances obtained in 3.2.2 and the calibration graph.
500
()mm−+()m−m×
12 s b
10
w SiO=×100 (1)
()
2
m
where
m is the mass from 9.2.2.3 or 9.2.3.3 of ISO 21079-1:2008, in grams;
1
2 © ISO 2008 – All rights reserved

---------------------- Page: 12 ----------------------

SIST EN ISO 21079-2:2008
ISO 21079-2:2008(E)
m is the mass from the blank prepared in accordance with 9.2.2.4 or 9.2.3.4 of ISO 21079-1:2008, in
2
grams;
m is the mass of silicon(IV) oxide in the aliquot portion of stock solution (S1) or (S’1), in grams;
s
m is the mass of silicon(IV) oxide in the aliquot portion of blank solution (B1) or (B’1), in grams;
b
m is the mass of the test portion prepared in accordance with ISO 21079-1:2008, in grams.
3.3 Molybdenum blue method
3.3.1 Principle
An aliquot portion of the stock solution (S’’1) is treated with ammonium molybdate and the silicomolybdate is
reduced to yield molybdenum blue, the absorbance of which is measured.
3.3.2 Procedure
Transfer the specified volume of stock solution (S’’1) (see Annex A of ISO 21079-1:2008) to two plastic
beakers and add, to each, the specified volume of blank solution (B’’1) (see Annex A of ISO 21079-1:2008).
Add 2 ml of hydrofluoric acid (1+9), mix with a plastic rod and allow to stand for 10 min. Then add 50 ml of
boric acid solution and dilute to about 80 ml with water. Add 5 ml of ammonium molybdate solution while
mixing at a temperature of 20 °C to 30 °C and allow to stand for 10 min. Add 20 ml of tartaric acid solution
while stirring. After 1 min, add 10 ml of L (+)-ascorbic acid solution while stirring. Transfer each solution to two
200 ml plastics volumetric flasks, dilute to the mark with water and mix. Allow to stand for 60 min and measure
the absorbance of the solutions in a 10 mm cell at a wavelength of 650 nm against water. Take the mean
value of the two measurements for the calculation of silica content.
The volume of the aliquot portions from stock solution (S’’1) and the blank solution are given in Table 1
depending on the mass fraction of silicon(IV) oxide.
Table 1 — Aliquot volume of stock solution (S’’1) and blank solution (B’’1)
Mass fraction of SiO Volume of stock solution (S’’1) Volume of blank solution (B’’1)
2
% ml ml
< 4 20 0
W 4, u 8
10 10

When the difference between two measurements exceeds 0,005 absorbance units, repeat the procedure
given in 9.2.4.3 of ISO 21079-1:2008.
The spectrophotometer should give a value of less than 0,002 absorbance units as the difference between
two repeated measurements of identical solutions at an absorbance level of about 1,00.
3.3.3 Blank test
Carry out the procedure described in 3.3.2 using blank solution (B’’1) (see Annex A of ISO 21079-1:2008).
3.3.4 Plotting of calibration graph
Transfer 0 ml (as reference), 2 ml, 4 ml, 6 ml, 8 ml and 10 ml aliquot portions of silicon(IV) oxide standard
solution into six 100 ml plastic beakers and add, to each, 10 ml of blank solution. Treat these solutions as
described in 3.3.2, measure the absorbance against the reference solution and plot the absorbance against
the amounts of silica.
© ISO 2008 – All rights reserved 3

---------------------- Page: 13 ----------------------

SIST EN ISO 21079-2:2008
ISO 21079-2:2008(E)
3.3.5 Calculation
Calculate the mass fraction of silicon(IV) oxide, w(SIO ), expressed as a percentage, using Equation (2).
2
()mm−
500
sb
w SiO=××100 (2)
()
2
mV
where
m is the silica in the aliquot portion of stock solution (S’’1), in grams;

s
m is the silica in the aliquot portion of blank solution (B’’1), in grams;

b
V is the volume of the aliquot portion taken from stock solution (S’’1), in millilitres;
m is the mass of the test portion, in grams.
4 Determination of aluminium oxide
4.1 General
The determination of aluminium oxide is carried out using one of the following methods.
a) Cation-exchange column separation: trans-1,2-Cyclohexanediamine-N,N,N’,N’-tetraacetic acid (hydrate)
(CyDTA) – Zinc back titration method;
b) Cupferron separation: CyDTA – Zinc back titration method.
4.2 Cation-exchange column separation: CyDTA – Zinc back titration method
4.2.1 Principle
An aliquot portion of stock solution (S1), (S’1) or (S’’1) is pipetted into a cation-exchange resin column and
cation, such as aluminium ion, is absorbed into the ion-exchange resin. 0,8 mol/l hydrofluoric acid and
0,65 mol/l boric acid solution is poured into the column, so that the zirconium and titanium flows out.
Hydrofluoric acid (1+200) is poured into the column in order to elute the aluminium. The eluate is evaporated
with the addition of sulfuric acid. The boric acid and hydrofluoric acid are removed and then dissolved into the
hydrochloric acid. CyDTA solution is added and a chelate compound of aluminium CyDTA is formed by
adjusting the pH with ammonia water. The pH is further adjusted by the addition of hexamethylenetetramine.
The excess amount of CyDTA is back-titrated by zinc standard solution using xylenol orange as an indicator.
4.2.2 Procedure
4.2.2.1 Pour a 50 ml aliquot portion of stock solution (see Annex A of ISO 21079-1:2008) into a
cation-exchange resin column (see ISO 26845). Pour 10 ml of eluent A (see 5.1.25 of ISO 26845:2008) on the
inner side of the column twice, followed by a further 60 ml of eluent A.
Up to this point, eluate is unnecessary.
NOTE It is not until the former solution ceases to drip out of the end of the column that further additions can be
poured. The same applies to the following procedure.
4.2.2.2 Place a platinum dish (e.g. 150 ml) below the lower end of the column and pour 10 ml of eluent B
(see 5.1.26 of ISO 26845:2008) on the inner side of the column twice. Pour 80 ml of eluent B into the column
to elute aluminium.
4 © ISO 2008 – All rights reserved

---------------------- Page: 14 ----------------------

SIST EN ISO 21079-2:2008
ISO 21079-2:2008(E)
Regenerate the column as follows. Prepare a 100 ml plastic beaker below the end of the column and pour
10 ml of hydrochloric acid (1+2) on the inner side of the column twice. Pour 100 ml of hydrochloric acid (1+2)
on the inner side of the column to elute iron, calcium, magnesium, etc.
This solution can be used for the determination of calcium oxide if the procedure is carried out using the
following steps. Transfer the solution to a 150 ml platinum dish and evaporate until dry on a steam bath in a
fume cupboard. Add 5 ml of hydrochloric acid (1+2) 30 ml of water and transfer to a steam bath to facilitate the
dissolution of the melt. Cool and dilute the solution to 100 ml in a volumetric flask. In the case of FAAS, add
10 ml of lanthanum solution before diluting to 100 ml.
4.2.2.3 Pour 70 ml of water into the column. Add 50 ml of sulfuric acid (1+1) to the eluate obtained in
accordance with 4.2.2.2, evaporate by heating on a hot plate until the white smoke of the sulfuric acid appears.
Cool and wash the inner side of the beaker with a small quantity of water and heat until the white smoke of
sulfuric acid appears. When the amount of the solution is about 2 ml, allow to cool and add 10 ml of
hydrochloric acid (1+1). Dissolve by heating and transfer to a 300 ml beaker.
4.2.2.4 Allow to cool and add of 2 ml of hydroxylammonium chloride while mixing. Add a precisely known
amount of 0,02 mol/l CyDTA standard solution and drop in ammonia solution (1+1) and ammonia solution
(1+9) between pH 2,9 and pH 3,1 using a pH meter. If excessive ammonia water is added, the pH is adjusted
to less than 3 by adding hydrochloric acid (1+1), and, subsequently, the identical adjustment procedure is
carried out. Add hexamethylenetetramine between pH 5,5 and pH 5,8 using a pH meter, add 4 to 5 drops of
xylenol orange solution as an indicator and titrate with 0,02 mol/l of zinc standard solution. When the colour
starts to change from yellow to the first appearance of a permanent reddish colour, carry out titration gently
while mixing.
NOTE The relation between the volume of the aliquot portion of 0,02 mol/l CyDTA standard solution and the mass
fraction of aluminium oxide is given in Table 2.
Table 2 — Volume of 0,02 mol/l CyDTA standard solution
Mass fraction of aluminium oxide CyDTA standard solution
% ml
< 15 10
W 15, < 35 20
W 35, < 55 30
W 55, < 75 40
W 75 50

4.2.3 Blank test
Transfer 200 ml aliquot portion of blank solution B1, B’1 or B’’1 (see Annex A of ISO 21079-1:2008) and carry
out the procedure given in 4.2.2.
4.2.4 Calculation
Calculate the mass fraction of aluminium oxide, w(Al O ), expressed as a percentage, in the sample using
2 3
Equation (3).
VV−×F× 0,001019 6
( )
500
21
w Al O=××100 (3)
()
23
m 50
where
V is the used quantity of 0,02 mol/l zinc standard solution in 4.2.2.4 in millilitres;
1
© ISO 2008 – All rights reserved 5

---------------------- Page: 15 ----------------------

SIST EN ISO 21079-2:2008
ISO 21079-2:2008(E)
V is the used quantity of 0,02 mol/l zinc standard solution in 4.2.3 in millilitres;
2
F is the factor of 0,02 mol/l zinc standard solution (see 5.2.17 of ISO 21079-1:2008);
0,001 019 6 is the mass equivalent of Al O ;
2 3
m is the mass of the sample in grams.
4.3 Cupferron separation-CyDTA-Zinc back titration method
4.3.1 Principle
Hydrochloric acid is added to an aliquot portion of stock solution (S1), (S’1) or (S’’1) to adjust the acidity. Iron,
titanium, manganese and zirconium are separated from the solution by solvent extraction with cupferron
solution and the precipitate removed by dissolution in chloroform. The organic phase is discarded. Excess
CyDTA solution is added to the aqueous solution after adjusting the pH with ammonia solution, and a chelate
compound of aluminium CyDTA is formed. The pH is further adjusted by the addition of ammonium acetate
buffer solution and an equivalent volume of ethanol is added to the solution. The amount of excess CyDTA is
determined by back-titration with standard zinc solution using dithizone as an indicator and the content of
aluminium oxide calculated.
4.3.2 Procedure
Transfer a 200 ml aliquot portion of the stock solution (S1), (S’1) or (S’’1) (see Annex A of ISO 21079-1:2008)
to a beaker (500 ml), add 20 ml of hydrochloric acid, cool to under 5 °C and keep at this temperature using
iced water. Add powdery filter paper (e.g. 0,05 g), then drop in 25 ml of cupferron solution and cool to under
5 °C while mixing. After complete mixing, allow to stand for 5 min. Filter the solution with medium filter paper
into a beaker (500 ml), and wash the precipitate 10 times with hydrochloric acid (1+9) which has been cooled
to under 5 °C, as above. Use the precipitate together with the filter paper for the determination of zirconium
oxide (including hafnium oxide).
The temperature should be kept as low as possible.
Evaporate the filtrate and washing solutions to about 20 ml on a steam bath, then cover with a watch glass,
add 10 ml of nitric acid and 5 ml of sulfuric acid (1+1), and boil gently for about 10 min on a sand bath.
Remove the watch glass, rinse the watch glass with water, and continue the evaporation carefully, then
evaporate until the white smoke of sulfuric acid appears.
Allow to cool, add 10 ml of hydrochloric acid (1+1) and about 100 ml of water, then heat to dissolve the salts.
Allow to cool, and dilute to 250 ml in a volumetric flask. Transfer a 100 ml aliquot portion of the solution and
add 2 ml of hydroxylammonium chloride while mixing. Add a precisely known amount of 0,02 mol/l CyDTA
standard solution and drop in ammonia solution (1+1), and ammonia solution (1+9) of between pH 2,9 and 3,1
using a pH meter. If ammonia water is added excessively, the pH is adjusted to less than 3 by adding
hydrochloric acid (1+1), then, subsequently, the identical adjustment procedure is carried out. Add
hexamethylenetetramine of between pH 5,5 and 5,8 using a pH meter, add 4 to 5 drops of xylenol orange
solution as an indicator, and titrate with 0,02 mol/l zinc standard solution. When the colour starts to change
from yellow to the first appearance of a permanent reddish colour, carry out titration gently while mixing.
NOTE The relation between the volume of the aliquot portion of 0,02 mol/l CyDTA standard solution and the mass
fraction of aluminium oxide is shown in Table 3.
6 © ISO 2008 – All rights reserved

---------------------- Page: 16 ----------------------

SIST EN ISO 21079-2:2008
ISO 21079-2:2008(E)
Table 3 — Volume of 0,02 mol/l CyDTA solution
Mass fraction of aluminium oxide CyDTA solution
% ml
< 20 20
W 20, < 35 30
W 35, < 60 50
W 60 70

4.3.3 Blank test
Carry out the procedure described in
...