SIST EN ISO 21587-1:2008

Chemical analysis of aluminosilicate refractory products (alternative to the X-ray fluorescence method) - Part 1: Apparatus, reagents, dissolution and gravimetric silica (ISO 21587-1:2007)

This part of ISO 21587 specifies reagents, dissolution and gravimetric silica analysis for the chemical analysis of aluminosilicate refractory products and raw materials. This part of ISO 21587 gives alternatives to the X-ray fluorescence (XRF) method given in ISO 12677:2003, Chemical analysis of refractory products by XRF - Fused cast bead method. This part of ISO 21587 should be used in conjunction with ISO 21587-2 and ISO 21587-3, which give the analytical procedures for the determination of the following: silicon(IV) oxide (SiO2) aluminium oxide (Al2O3) iron(III) oxide (total iron oxide calculated as Fe2O3) titanium(IV) oxide (TiO2) manganese(II) oxide (MnO) calcium oxide (CaO) magnesium oxide (MgO) sodium oxide (Na2O) potassium oxide (K2O) chromium(III) oxide (Cr2O3) zirconium oxide (ZrO2) phosphorous(V) oxide (P2O5).

Chemische Analyse feuerfester Erzeugnisse aus Alumosilicat (Alternative zur Röntgenfluoreszenzanalyse) - Teil 1: Geräte, Reagenzien, Aufschluss und gravimetrische Bestimmung von Silicium(IV)-oxid (ISO 21587-1:2007)

Dieser Teil von ISO 21587 legt die Reagenzien, den Aufschluss und die gravimetrische Bestimmung von Silicium(IV)-oxid für die chemische Analyse von feuerfesten Erzeugnissen und Rohstoffen aus Alumosilicat fest.
Dieser Teil von ISO 21587 gibt Alternativen zur Röntgenfluoreszenzanalyse (RFA), die in ISO 12677:2003, Chemische Analyse von feuerfesten Erzeugnissen durch RFA — Schmelzaufschluss Verfahren, festgelegt ist.
Dieser Teil von ISO 21587 sollte in Verbindung mit ISO 21587 2 und ISO 21587 3 angewendet werden, in denen die Analysenverfahren für die folgenden Bestimmungen gegeben werden:
   Silicium(IV) oxid (SiO2);
   Aluminiumoxid (Al2O3);
   Eisen(III) oxid (Gesamteisengehalt, berechnet als Fe2O3);
   Titan(IV) oxid (TiO2);
   Mangan(II) oxid (MnO);
   Calciumoxid (CaO);
   Magnesiumoxid (MgO);
   Natriumoxid (Na2O);
   Kaliumoxid (K2O);
   Chrom(III) oxid (Cr2O3);
   Zirkoniumoxid (ZrO2);
   Phosphor(V) oxid (P2O5).

Analyse chimique des produits réfractaires d'aluminosilicates (méthode alternative a la méthode par fluorescence de rayons X) - Partie 1: Appareillage, réactifs, dissolution et teneur en silice par gravimétrie (ISO 21587-1:2007)

L'ISO 21587-1:2007 spécifie les réactifs, la dissolution et l'analyse de la silice gravimétrique pour les analyses chimiques des produits et matières premières réfractaires d'aluminosilicates.
L'ISO 21587-1:2007 fournit une méthode alternative à la méthode par fluorescence de rayons X (FRX) donnée dans l'ISO 12677:2003.

Kemijska analiza alumosilikatnih ognjevzdržnih izdelkov (alternativa rentgenski fluorescenčni metodi) - 1. del: Aparati, reagenti, raztapljanje in gravimetrična silika (ISO 21587-1:2007)

General Information

• Status: Published
• Publication Date: 17-Feb-2008
• ICS: 81.080 - Refractories
• Technical Committee: IKER - Ceramics
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 15-Oct-2007
• Due Date: 20-Dec-2007
• Completion Date: 18-Feb-2008
• Ref Project: EN ISO 21587-1:2007 - Chemical analysis of aluminosilicate refractory products (alternative to the X-ray fluorescence method) - Part 1: Apparatus, reagents, dissolution and gravimetric silica (ISO 21587-1:2007)

Relations

• Replaces: SIST EN 955-2:1998 - Chemical analysis of refractory products - Part 2: Products containing silica and/or alumina (wet method)
• Effective Date: 01-Mar-2008
• Replaces: SIST ENV 955-4:1998 - Chemical analysis of refractory products - Part 4: Products containing silica and/or alumina (Analysis by Flame Atomic Absorption Spectrometry (FAAS) and Inductively Coupled Plasma Atomic Emission Spectrography (ICP)
• Effective Date: 01-Mar-2008

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 21587-1:2008
01-marec-2008
1DGRPHãþD
SIST EN 955-2:1998
SIST ENV 955-4:1998
.HPLMVNDDQDOL]DDOXPRVLOLNDWQLKRJQMHY]GUåQLKL]GHONRYDOWHUQDWLYDUHQWJHQVNL
IOXRUHVFHQþQLPHWRGLGHO$SDUDWLUHDJHQWLUD]WDSOMDQMHLQJUDYLPHWULþQD
VLOLND,62
Chemical analysis of aluminosilicate refractory products (alternative to the X-ray
fluorescence method) - Part 1: Apparatus, reagents, dissolution and gravimetric silica
(ISO 21587-1:2007)
Chemische Analyse feuerfester Erzeugnisse aus Alumosilicat (Alternative zur
Röntgenfluoreszenzanalyse) - Teil 1: Geräte, Reagenzien, Aufschluss und
gravimetrische Bestimmung von Silicium(IV)-oxid (ISO 21587-1:2007)
Analyse chimique des produits réfractaires d'aluminosilicates (méthode alternative a la
méthode par fluorescence de rayons X) - Partie 1: Appareillage, réactifs, dissolution et
teneur en silice par gravimétrie (ISO 21587-1:2007)
Ta slovenski standard je istoveten z: EN ISO 21587-1:2007
ICS:
81.080
SIST EN ISO 21587-1:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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

EUROPEAN STANDARD
EN ISO 21587-1
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2007
ICS 81.080 Supersedes EN 955-2:1995, ENV 955-4:1997
English Version
Chemical analysis of aluminosilicate refractory products
(alternative to the X-ray fluorescence method) - Part 1:
Apparatus, reagents, dissolution and gravimetric silica (ISO
21587-1:2007)
Analyse chimique des produits réfractaires Chemische Analyse feuerfester Erzeugnisse aus
d'aluminosilicates (méthode alternative à la méthode par Alumosilicat (Alternative zur Röntgenfluoreszenzanalyse) -
fluorescence de rayons X) - Partie 1: Appareillage, réactifs, Teil 1: Geräte, Reagenzien, Aufschluss und gravimetrische
dissolution et teneur en silice par gravimétrie (ISO 21587- Bestimmung von Silicium(IV)-oxid (ISO 21587-1:2007)
1:2007)
This European Standard was approved by CEN on 13 September 2007.
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
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21587-1:2007: E
worldwide for CEN national Members.

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

EN ISO 21587-1:2007 (E)






Foreword



The text of ISO 21587-1:2007 has been prepared by Technical Committee ISO/TC 33
"Refractories” of the International Organization for Standardization (ISO) and has been taken
over as EN ISO 21587-1:2007 by 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 March 2008, and conflicting national
standards shall be withdrawn at the latest by March 2008.

This document supersedes EN 955-2:1995 and ENV 955-4:1997.

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 United
Kingdom.


Endorsement notice

The text of ISO 21587-1:2007 has been approved by CEN as EN ISO 21587-1:2007 without any
modifications.

2

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

INTERNATIONAL ISO
STANDARD 21587-1
First edition
2007-03-01

Chemical analysis of aluminosilicate
refractory products (alternative to the
X-ray fluorescence method) —
Part 1:
Apparatus, reagents, dissolution and
gravimetric silica
Analyse chimique des produits réfractaires d'aluminosilicates (méthode
alternative à la méthode par fluorescence de rayons X) —
Partie 1: Appareillage, réactifs, dissolution et teneur en silice par
gravimétrie





Reference number
ISO 21587-1:2007(E)
©
ISO 2007

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

ISO 21587-1:2007(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.


©  ISO 2007
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 2007 – All rights reserved

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

ISO 21587-1:2007(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 2
3 Reagents. 2
4 Dissolution and gravimetric silica . 6

© ISO 2007 – All rights reserved iii

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

ISO 21587-1:2007(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 21587-1 was prepared by Technical Committee ISO/TC 33, Refractories.
ISO 21587 consists of the following parts, under the general title Chemical analysis of aluminosilicate
refractory products (alternative to the X-ray fluorescence method):
⎯ Part 1: Apparatus, reagents, dissolution and gravimetric silica
⎯ Part 2: Wet chemical analysis
⎯ Part 3: Inductively coupled plasma and atomic absorption spectrometry methods

iv © ISO 2007 – All rights reserved

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

INTERNATIONAL STANDARD ISO 21587-1:2007(E)

Chemical analysis of aluminosilicate refractory products
(alternative to the X-ray fluorescence method) —
Part 1:
Apparatus, reagents, dissolution and gravimetric silica
1 Scope
This part of ISO 21587 specifies reagents, dissolution and gravimetric silica analysis for the chemical analysis
of aluminosilicate refractory products and raw materials.
This part of ISO 21587 gives alternatives to the X-ray fluorescence (XRF) method given in ISO 12677:2003,
Chemical analysis of refractory products by XRF — Fused cast bead method.
This part of ISO 21587 should be used in conjunction with ISO 21587-2 and ISO 21587-3, which give the
analytical procedures for the determination of the following:
⎯ silicon(IV) oxide (SiO )
2
⎯ aluminium oxide (Al O )
2 3
⎯ iron(III) oxide (total iron oxide calculated as Fe O )
2 3
⎯ titanium(IV) oxide (TiO )
2
⎯ manganese(II) oxide (MnO)
⎯ calcium oxide (CaO)
⎯ magnesium oxide (MgO)
⎯ sodium oxide (Na O)
2
⎯ potassium oxide (K O)
2
⎯ chromium(III) oxide (Cr O )
2 3
⎯ zirconium oxide (ZrO )
2
⎯ phosphorous(V) oxide (P O )
2 5
© ISO 2007 – All rights reserved 1

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

ISO 21587-1:2007(E)
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 21587-2, Chemical analysis of aluminosilicate refractory products (alternative to the X-ray fluorescence
method) — Part 2: Wet chemical analysis
ISO 21587-3, Chemical analysis of aluminosilicate refractory products (alternative to the X-ray fluorescence
method) — Part 3: Inductively coupled plasma and atomic absorption spectrometry methods
ISO 26845, Chemical analysis of refractories — General requirements for wet chemical analysis, atomic
absorption spectrometry and inductively coupled plasma methods
3 Reagents
Standard solutions specified in ISO 26845 and the following reagents.
3.1 Standard volumetric solutions
3.1.1 Standard volumetric CyDTA solution, c(CyDTA) = 0,05 mol/l.
Dissolve 18 g of 1,2 cyclohexanediamine-N,N,N’,N’-tetraacetic acid monohydrate (CyDTA) in 500 ml of water
by the progressive addition of the minimum amount of potassium hydroxide solution.
NOTE Approximately 25 ml is required. Determine the exact strength of this solution by titration against the standard
volumetric zinc solution, c(Zn) = 0,05 mol/l.
3.1.2 Standard volumetric CyDTA solution, c(CyDTA) = 0,02 mol/l.
Add 16 ml of sodium hydroxide solution (100 g/l) and approximately 150 ml of water to 7,30 g of
1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid monohydrate (CyDTA), and dissolve by heating. After
cooling, dilute to 1 000 ml with water.
NOTE Approximately 25 ml is required. Determine the exact strength of this solution by titration against the standard
volumetric zinc solution, c(Zn) = 0,02 mol/l.
3.1.3 Standard volumetric EDTA solution, c(EDTA) = 0,012 5 mol/l.
Dissolve 5 g of EDTANa (ethylenediamine-tetraacetic acid disodium salt, dihydrate) in water and dilute to
2
1 000 ml in a volumetric flask. Store in a plastic bottle.
Standardize against calcium as follows.
Pipette 25 ml of standard calcium oxide solution (1 mg/ml), into a 500 ml conical flask, add 10 ml of potassium
hydroxide solution, and dilute to about 200 ml. Add about 0,015 g of screened Calcein indicator, and titrate
with the standard volumetric EDTA solution, from a fluorescent green colour to pink.
Standardize against magnesium as follows.
Pipette 25 ml of standard magnesium oxide solution (1 mg/ml), into a 500 ml conical flask, add 20 drops of
hydrochloric acid (concentrated) and 20 ml of ammonia solution (concentrated), and dilute to about 200 ml.
Add about 0,04 g of methylthymol blue complexone indicator, and titrate with the standard volumetric EDTA
solution.
2 © ISO 2007 – All rights reserved

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

ISO 21587-1:2007(E)
3.1.4 Standard volumetric zinc solution, c(Zn) = 0,05 mol/l.
Wash the surface of about 5 g of pellets of metallic zinc in about 50 ml of hydrochloric acid (1+1) to remove
oxide, then wash successively with water, ethanol and diethyl ether. Weigh 3,269 g of the dried pellets,
dissolve in 10 ml of hydrochloric acid (concentrated) and 50 ml of water, cool and dilute to the mark in a
1 000 ml volumetric flask. 1 ml of this zinc solution (0,05 mol/l) is equivalent to 2,55 mg of Al O .
2 3
3.1.5 Standard volumetric zinc solution, c(Zn) = 0,02 mol/l.
Wash the surface of the zinc (purity, more than 99,9 % by mass) with hydrochloric acid (1+3) and dissolve the
oxidized layer. Subsequently, wash with water, ethanol and diethyl ether in succession, then dry in a
desiccator. Weigh 0,66 g (recorded to 0,1 mg) of zinc, transfer it to a 300 ml beaker, and cover with a watch
glass. Add 20 ml of water and 10 ml of nitric acid carefully, and heat to dissolve on a steam bath. After cooling,
dilute to 1 000 ml in a volumetric flask with water.
Calculate the factor of this zinc solution using the following equation:
mA
F=× (1)
0,653 9 100
where
F is the factor of this zinc solution;
m is the mass, in grams, of the weighed zinc;
A is the purity, in percentage by mass, of the zinc.
3.2 Standard solutions
3.2.1 Standard aluminium oxide solution, Al O 1 mg/ml.
2 3
Wash the surface of a sufficient amount of aluminum metal (purity more than 99,9 % by mass) with
hydrochloric acid (1+4) to dissolve the oxidized layer. Then wash with water, ethanol and diethyl ether in
succession, and dry in a desiccator. Weigh 0,529 2 g of aluminium and transfer to a 250 ml beaker. Cover
with a watch glass, add 20 ml hydrochloric acid (1+1), and heat to dissolve. After cooling, dilute to 1 000 ml in
a volumetric flask with water.
3.2.2 Standard calcium oxide solution, CaO 1 mg/ml.
Dissolve 1,785 g of pure calcium carbonate, previously dried at 150 °C, in a slight excess of dilute
hydrochloric acid (1 + 4) in a 250 ml beaker, covered with a watch glass. Boil to expel carbon dioxide, cool
and dilute to 1 000 ml in a volumetric flask.
3.2.3 Standard chromium(III) oxide solution, Cr O 1 mg/ml.
2 3
Dry about 2 g to 3 g of potassium dichromate at 110 °C for at least 2 h. Weigh 1,935 g of this and dissolve in
water, diluting to 1 000 ml in a volumetric flask.
3.2.4 Dilute standard chromium(III) oxide solution, Cr O 0,025 mg/ml.
2 3
Pipette 25 ml of the standard chromic oxide solution (1 mg/ml) to a 1 000 ml volumetric flask and dilute to the
mark with water. Prepare this solution freshly when required.
3.2.5 Standard iron(III) oxide solution, Fe O 1 mg/ml.
2 3
Wash the surface of a sufficient amount of iron metal (purity greater than 99,9 %) with hydrochloric acid (1+4).
Then dissolve the oxidized layer, and wash with water, ethanol and diethyl ether in succession. Then dry in a
© ISO 2007 – All rights reserved 3

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

ISO 21587-1:2007(E)
desiccator. Weigh 0,699 4 g of this, transfer to a beaker (200 ml), and cover with a watch glass. Add 40 ml of
hydrochloric acid (1+1), and heat on a steam bath until it is dissolved. After cooling, dilute to 1 000 ml in a
volumetric flask with water.
3.2.6 Diluted standard iron(III) oxide solution, Fe O 0,2 mg/ml.
2 3
Pipette 20 ml of the standard iron(III) oxide solution (Fe O 1 mg/ml) into a 1 000 ml volumetric flask and
2 3
dilute to the mark with water. Prepare this solution freshly when required.
3.2.7 Dilute standard iron (III) oxide solution, Fe O 0,04 mg/ml.
2 3
Pipette 4 ml of the standard iron(III) oxide solution (Fe O 1 mg/ml) into a 1 000 ml volumetric flask and dilute
2 3
to the mark with water. Prepare this solution freshly when required.
3.2.8 Standard magnesium oxide solution, MgO, 1 mg/ml.
Wash the surface of a sufficient amount of magnesium metal (purity more than 99,9 % by mass) with
hydrochloric acid (1+1) to dissolve the oxidized layer. Then wash with water, ethanol and diethyl ether in
succession, and dry in a desiccator. Weigh 0,301 5 g of the washed magnesium, transfer to a 200 ml beaker
and cover with a watch glass. Add 20 ml of hydrochloric acid (1+1), and heat on a steam bath until dissolved.
After cooling, transfer to a 500 ml volumetric flask, and dilute to the mark with water.
3.2.9 Standard manganese(II) oxide solution, MnO 1 mg/ml.
Wash the surface of a sufficient mass of manganese metal (purity more than 99,9 % by mass) with
hydrochloric acid (1+3) to dissolve the oxidized layer. Then wash with water, ethanol and diethyl ether in
succession and dry in a desiccator. Weigh 0,774 5 g of this metal, transfer to a 200 ml beaker and cover with
a watch glass. Add 40 ml of nitric acid (1+1) and heat to dissolve. After cooling, transfer to a 1 000 ml
volumetric flask.
3.2.10 Dilute standard manganese(II) oxide solution, MnO 0,04 mg/ml.
Transfer 40 ml of the standard manganese(II) oxide solution (MnO 1 mg/ml) into a 1 000 ml volumetric flask
and dilute to the mark with water. Prepare this solution freshly as required.
3.2.11 Standard phosphorus(V) oxide solution, P O 1 mg/ml.
2 5
Heat about 3 g of potassium dihydrogen phosphate at 110 °C ± 5 °C for 3 h, and allow to cool in a desiccator.
Weigh 1,917 6 g, transfer to a beaker and dissolve with approximately 300 ml of water. Dilute to 1 000 ml in a
volumetric flask with water.
3.2.12 Dilute standard phosphorus(V) oxide solution, P O 0,04 mg/ml.
2 5
Transfer precisely 40 ml of the standard phosphorus(V) oxide solution (P O 1 mg/ml) to a 1 000 ml
2 5
volumetric flask, and dilute to the mark with water.
3.2.13 Dilute standard phosphorus(V) oxide solution, P O 0,01 mg/ml.
2 5
Pipette 10 ml of the standard phosphorus(V) oxide solution (P O 1 mg/ml) into a 1 000 ml volumetric flask,
2 5
and dilute to the mark with water. Prepare this solution freshly when required.
3.2.14 Standard potassium oxide solution, K O 1 mg/ml.
2
Transfer 1 g to 1,5 g of potassium chloride to a platinum crucible (e.g. 30 ml) and ignite at 600 °C ± 25 °C for
approximately 60 min. Allow the crucible and contents to cool in a desiccator. Weigh 0,791 4 g of this and
transfer to a 200 ml beaker. Dissolve in 100 ml of water, transfer to a 500 ml volumetric flask, and dilute to the
mark with water.
4 © ISO 2007 – All rights reserved

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

ISO 21587-1:2007(E)
3.2.15 Standard silicon(IV) oxide solution, SiO 1 mg/ml.
2
Weigh 1,5 to 2 g of silicon(IV) oxide (purity, greater that 99,9 % by mass) in a platinum crucible (e.g. 30 ml)
and heat for 30 min at 1 150 °C ± 50 °C. Cool in a desiccator and then weigh 1,000 g of this silicon(IV) oxide
into a platinum crucible (e.g. 50 ml). Fuse the silicon(IV) oxide with 5,0 g of anhydrous sodium carbonate.
Cool and wipe the outside of the crucible, and dissolve in warm water (150 ml) in a plastic 200 ml beaker,
while stirring with a plastic rod. Cool and dilute without heating to 1 000 ml in a volumetric flask. Transfer this
solution to a plastics bottle immediately.
3.2.16 Dilute standard silicon(IV) oxide solution, SiO 0,2 mg/ml.
2
Pipette 40 ml of the standard silicon(IV) oxide solution (SiO 1 mg/ml) into a 200 ml volumetric flask, and
2
dilute to the mark with water. Prepare this solution freshly when required.
3.2.17 Dilute standard silicon(IV) oxide solution, SiO 0,04 mg/ml.
2
Pipette 20 ml of the standard silicon(IV) oxide solution (SiO 1 mg/ml) into a 500 ml volumetric flask and dilute
2
to the mark with water. Prepare this solution freshly when required.
3.2.18 Standard sodium oxide solution, Na O 1 mg/
...