EN ISO 21068-2:2008

SLOVENSKI STANDARD
01-december-2008
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Chemical analysis of silicon-carbide-containing raw materials and refractory products -
Part 2: Determination of loss on ignition, total carbon, free carbon and silicon carbide,
total and free silica and total and free silicon (ISO 21068-2:2008)
Chemische Analyse von Siliciumcarbid enthaltenden Rohstoffen und feuerfesten
Erzeugnissen - Teil 2: Bestimmung des Glühverlustes und Gehaltes an
Gesamtkohlenstoff, freiem Kohlenstoff und Siliciumcarbid, des Gehaltes an gesamtem
und freiem Silicium(IV)-oxid sowie an gesamtem und freiem Silicium (ISO 21068-2:2008)
Analyse chimique des matières premières et des produits réfractaires contenant du
carbure de silicium - Partie 2: Détermination de la perte au feu, du carbone total, du
carbone libre et du carbure de silicium, de la silice totale et libre, et du silicium total et
libre (ISO 21068-2:2008)
Ta slovenski standard je istoveten z: EN ISO 21068-2:2008
ICS:
81.080 Ognjevzdržni materiali Refractories
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 21068-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2008
ICS 81.080
English Version
Chemical analysis of silicon-carbide-containing raw materials
and refractory products - Part 2: Determination of loss on
ignition, total carbon, free carbon and silicon carbide, total and
free silica and total and free silicon (ISO 21068-2:2008)
Analyse chimique des matières premières et des produits Chemische Analyse von Siliciumcarbid enthaltenden
réfractaires contenant du carbure de silicium - Partie 2: Rohstoffen und feuerfesten Erzeugnissen - Teil 2:
Détermination de la perte au feu, du carbone total, du Bestimmung des Glühverlustes und Gehaltes an
carbone libre et du carbure de silicium, de la silice totale et Gesamtkohlenstoff, freiem Kohlenstoff und Siliciumcarbid,
libre, et du silicium total et libre (ISO 21068-2:2008) des Gehaltes an gesamtem und freiem Silicium(IV)-oxid
sowie an gesamtem und freiem Silicium (ISO 21068-
2:2008)
This European Standard was approved by CEN on 11 July 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 21068-2:2008: E
worldwide for CEN national Members.

Contents Page
Foreword.3

Foreword
This document (EN ISO 21068-2:2008) 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 February 2009, and conflicting national standards shall be withdrawn
at the latest by February 2009.
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 21068-2:2008 has been approved by CEN as a EN ISO 21068-2:2008 without any
modification.
INTERNATIONAL ISO
STANDARD 21068-2
First edition
2008-08-01
Chemical analysis of silicon-carbide-
containing raw materials and refractory
products —
Part 2:
Determination of loss on ignition, total
carbon, free carbon and silicon carbide,
total and free silica and total and free
silicon
Analyse chimique des matières premières et des produits réfractaires
contenant du carbure de silicium —
Partie 2: Détermination de la perte au feu, du carbone total, du carbone
libre et du carbure de silicium, de la silice totale et libre, et du silicium
total et libre
Reference number
ISO 21068-2:2008(E)
©
ISO 2008
ISO 21068-2:2008(E)
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ISO 21068-2:2008(E)
Contents Page
Foreword .v
Introduction.vi
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Determination of change in mass.2
4.1 General .2
4.2 Determination of the loss on drying at 250 °C (LOD ) gravimetric method.2
4.3 Determination of the loss on calcination in argon (LOI ) .3
Ar
4.4 Determination of the change in mass by heat pretreatment in air.5
4.5 Determination of the change in mass at 750 °C (LOI ).6
4.6 Determination of loss on ignition at 850 °C (LOI ).7
4.7 Determination of loss on ignition at 1 050 °C (LOI ) .7
1 050
5 Determination of the total carbon content.8
5.1 General .8
5.2 Combustion techniques.9
5.3 Detection techniques .12
5.4 Detection methods .17
6 Determination of free carbon content .24
6.1 General .24
6.2 Sample decomposition by combustion .24
6.3 Detection techniques .24
6.4 Direct detection methods .24
6.5 Indirect detection methods.29
6.6 Direct determination of free carbon by wet oxidation.33
7 Determination of silicon carbide content, SiC.33
7.1 General .33
7.2 Determination of silicon carbide, SiC, by indirect quantitative method.34
7.3 Determination of silicon carbide, SiC, by direct quantitative method .34
7.4 Determination of silicon carbide SiC by ignition method at 750 °C.35
7.5 Determination of silicon carbide, SiC, by chemical method.36
8 Determination of total silicon content via silica.38
8.1 Principle.38
8.2 Reagents.38
8.3 Apparatus.38
8.4 Procedure.39
8.5 Blank test.39
8.6 Calculation .40
9 Determination of free silicon content.40
9.1 Principle.40
9.2 Pretreatment with hydrochloric acid .40
9.3 Silicon determination by hydrogen evolution .40
9.4 Silicon determination by silver displacement .43
10 Determination of silica content, SiO .45
10.1 General .45
10.2 Determination of free and/or combined silica content, SiO .45
ISO 21068-2:2008(E)
10.3 Determination of free silica, SiO .
...