oSIST prEN ISO 21068-2:2023
(Main)Chemical analysis of raw materials and refractory products containing silicon-carbide, silicon-nitride, silicon-oxynitride and sialon - Part 2: Determination of volatile components, total carbon, free carbon, silicon carbide, total and free silicon, free and surface silica (ISO/DIS 21068-2:2023)
Chemical analysis of raw materials and refractory products containing silicon-carbide, silicon-nitride, silicon-oxynitride and sialon - Part 2: Determination of volatile components, total carbon, free carbon, silicon carbide, total and free silicon, free and surface silica (ISO/DIS 21068-2:2023)
This part of ISO 21068 specifies analytical techniques for the determination of volatile components by thermal treatment at specified temperatures, and methods for the determination of the total carbon content, free carbon, silicon carbide, total and free silicon and free and surface silica content of silicon carbide, silicon nitride, silicon oxynitride and sialon containing raw materials and refractory products.
Chemische Analyse von Rohstoffen und feuerfesten Erzeugnissen, die Siliciumcarbid, Siliciumnitrid, Siliciumoxinitrid und Sialon enthalten - Teil2: Bestimmung des Gehaltes an flüchtigen Bestandteilen, Gesamtkohlenstoff, freiem Kohlenstoff, Siliziumcarbid, gesamtem und freiem Silizium, freiem und anhaltendem Siliziumdioxid (ISO/DIS 21068-2:2023)
Analyse chimique des matières premières et des produits réfractaires contenant du carbure de silicium, du nitrure de silicium, de l’oxynitrure de silicium et du sialon - Partie 2: Dosage des composés volatils, du carbone total, du carbone libre, du carbure de silicium, du silicium total et libre et de la silice libre et superficielle (ISO/DIS 21068-2:2023)
Kemijska analiza surovin in ognjevzdržnih izdelkov, ki vsebujejo silicijev karbid, silicijev nitrid, silicijev oksinitrid in sialon - 2. del: Določevanje hlapnih sestavin, celotnega ogljika, prostega ogljika, silicijevega karbida, celotnega in prostega silicija, prostega in površinskega silicija (ISO/DIS 21068-2:2023)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN ISO 21068-2:2023
01-julij-2023
Kemijska analiza surovin in ognjevzdržnih izdelkov, ki vsebujejo silicijev karbid,
silicijev nitrid, silicijev oksinitrid in sialon - 2. del: Določevanje hlapnih sestavin,
celotnega ogljika, prostega ogljika, silicijevega karbida, celotnega in prostega
silicija, prostega in površinskega silicija (ISO/DIS 21068-2:2023)
Chemical analysis of raw materials and refractory products containing silicon-carbide,
silicon-nitride, silicon-oxynitride and sialon - Part 2: Determination of volatile
components, total carbon, free carbon, silicon carbide, total and free silicon, free and
surface silica (ISO/DIS 21068-2:2023)
Chemische Analyse von Rohstoffen und feuerfesten Erzeugnissen, die Siliciumcarbid,
Siliciumnitrid, Siliciumoxinitrid und Sialon enthalten - Teil2: Bestimmung des Gehaltes an
flüchtigen Bestandteilen, Gesamtkohlenstoff, freiem Kohlenstoff, Siliziumcarbid,
gesamtem und freiem Silizium, freiem und anhaltendem Siliziumdioxid (ISO/DIS 21068-
2:2023)
Analyse chimique des matières premières et des produits réfractaires contenant du
carbure de silicium, du nitrure de silicium, de l’oxynitrure de silicium et du sialon - Partie
2: Dosage des composés volatils, du carbone total, du carbone libre, du carbure de
silicium, du silicium total et libre et de la silice libre et superficielle (ISO/DIS 21068-
2:2023)
Ta slovenski standard je istoveten z: prEN ISO 21068-2
ICS:
71.040.40 Kemijska analiza Chemical analysis
81.080 Ognjevzdržni materiali Refractories
oSIST prEN ISO 21068-2:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN ISO 21068-2:2023
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oSIST prEN ISO 21068-2:2023
DRAFT INTERNATIONAL STANDARD
ISO/DIS 21068-2
ISO/TC 33 Secretariat: BSI
Voting begins on: Voting terminates on:
2023-06-02 2023-08-25
Chemical analysis of raw materials and refractory products
containing silicon-carbide, silicon-nitride, silicon-
oxynitride and sialon —
Part 2:
Determination of volatile components, total carbon, free
carbon, silicon carbide, total and free silicon, free and
surface silica
ICS: 81.080
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
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STANDARDS MAY ON OCCASION HAVE TO
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Reference number
NATIONAL REGULATIONS.
ISO/DIS 21068-2:2023(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
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PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023
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oSIST prEN ISO 21068-2:2023
DRAFT INTERNATIONAL STANDARD
ISO/DIS 21068-2
ISO/TC 33 Secretariat: BSI
Voting begins on: Voting terminates on:
Chemical analysis of raw materials and refractory products
containing silicon-carbide, silicon-nitride, silicon-
oxynitride and sialon —
Part 2:
Determination of volatile components, total carbon, free
carbon, silicon carbide, total and free silicon, free and
surface silica
ICS: 81.080
This document is circulated as received from the committee secretariat.
COPYRIGHT PROTECTED DOCUMENT
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FOR COMMENT AND APPROVAL. IT IS
© ISO 2023
ISO/CEN PARALLEL PROCESSING
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All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
NOT BE REFERRED TO AS AN INTERNATIONAL
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NATIONAL REGULATIONS.
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ii
© ISO 2023 – All rights reserved
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023
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oSIST prEN ISO 21068-2:2023
ISO/DIS 21068-2:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Determination of volatile components by gravimetric methods .2
4.1 General . 2
4.2 Determination of the loss on drying at 250 °C (LOD ) . 2
250
4.2.1 Principle . 2
4.2.2 Apparatus . 2
4.2.3 Procedure . 2
4.2.4 Calculation . 3
4.3 Determination of the loss on ignition in argon (LOI ) . 3
Ar
4.3.1 Principle . 3
4.3.2 Apparatus . 3
4.3.3 Test assembly . 3
4.3.4 Reagents . 4
4.3.5 Procedure . 4
4.3.6 Calculation . 5
5 Determination of the total carbon content . 5
5.1 Scope . . 5
5.2 Combustion techniques . 5
5.2.1 Combustion in a resistance furnace with lead borate or tin as decomposing
agent . 5
5.2.2 Combustion in an induction furnace (IF) with metallic powder as
decomposing agent . 6
5.3 Detection techniques . 7
5.3.1 Coulometry . 7
5.3.2 Detection of the released carbon dioxide, CO , by infrared absorption (IR) . 8
2
5.3.3 Thermal conductivity (TC) method . 8
5.4 Expression of results . . 8
6 Determination of free carbon content . 8
6.1 General . 8
6.1.1 Direct methods . 9
6.1.2 Indirect methods . 14
7 Determination of silicon carbide content.17
7.1 General . 17
7.2 Determination of silicon carbide, SiC, by indirect method . 17
7.2.1 Principle . 17
7.2.2 Calculation . 17
7.2.3 Precision . 18
7.3 Determination of silicon carbide, SiC, by combustion methods . 18
7.3.1 Procedure . 18
7.3.2 Calculation . 18
7.4 Determination of silicon carbide, SiC, by combustion at 750 °C . 18
7.4.1 Principle . 18
7.4.2 Residue production . 18
7.4.3 Determination of the total carbon content of the residue . 19
7.4.4 Calculation . 19
8 Determination of total silicon content .20
9 Determination of free silicon content .20
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oSIST prEN ISO 21068-2:2023
ISO/DIS 21068-2:2023(E)
9.1 Principle . 20
9.2 Pretreatment with hydrochloric acid . 20
9.3 Determination of free silicon by hydrogen evolution . 20
9.3.1 Reagents . 20
9.3.2 Apparatus . 21
9.3.3 Mass of test portion . 21
9.3.4 Procedure .22
9.3.5 Blank test .23
9.3.6 Calculation . 23
10 Determination of free silica content .24
10.1 Principle . 24
10.2 Reagents . 24
10.3 Apparatus . 24
10.4 Sample preparation .25
10.5 Procedure . 25
10.5.1 Determination .26
10.5.2 Calculation and expression of SiO content . 26
2
11 Determination of surface silica content .26
12 Expression of results .26
13 Test report .27
Annex A (informative) Precision data .28
Annex B (informative) Examples of certified reference materials for calibration of carbon
analyser .34
Annex C (informative) Correction of the free carbon content in case of oxidation of SiC.35
Bibliography .36
iv
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oSIST prEN ISO 21068-2:2023
ISO/DIS 21068-2:2023(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 21068-2 was prepared by Technical Committee ISO/TC 33, Refractories.
ISO 21068 consists of the following parts, under the general title Chemical analysis of raw materials and
refractory products containing silicon-carbide, silicon-nitride, silicon-oxynitride and sialon:
— Part 1: General information and sample preparation
— Part 2: Determination of volatile components, total carbon, free carbon, silicon carbide, total and free
silicon, free and surface silica
— Part 3: Determination of nitrogen, oxygen and metallic and oxide constituents
— Part 4: XRD methods
v
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oSIST prEN ISO 21068-2:2023
ISO/DIS 21068-2:2023(E)
Introduction
[8]
ISO 21068, Parts 1 to 4, have been developed from the combination of EN 12698:2007, Parts 1 and
[9] [10 to 12]
2 , and ISO 21068:2008, Parts 1 to 3 . The latter has been originally developed from the
[1]
combination of Japanese standard JIS R 2011:2007 and work items developed within CEN. Because
there is a wide variety of laboratory equipment in use, the most commonly used methods are described.
[9]
The new ISO 21068, Part 4, is derived from the European standard EN 12698-2:2007 describing XRD
methods for the determination of mineralogical phases typically apparent in nitride and oxy-nitride
bonded silicon carbide refractory products using a Bragg-Brentano diffractometer.
ISO 21068, Parts 1 to 4, are applicable to the analysis of all refractory products classified in ISO 10081,
[2] to [5] [6]
Parts 1 to 4 (shaped) and ISO 1927-1 (unshaped) and raw materials containing carbon and/
or silicon carbide. Therefore, this part of ISO 21068 covers the full range of analysis from pure silicon
carbide to oxide refractory composition with a low content of silicon carbide and/or nitrides. Primarily,
this part of ISO 21068 provides methods to distinguish between different carbon-bound types like total
carbon (C ) and free carbon (C ) and derives from these two the silicon carbide content. The new
total free
Part 4 includes details of sample preparation and general principles for qualitative and quantitative
analysis of mineralogical phase composition. Quantitative determination of α-Si N , β-Si N , Si ON ,
3 4 3 4 2 2
AlN, and SiAlON are described.
If free carbon is present, the standard includes different temperature treatment in order to determine
the mass changes gravimetrically. Frequently, the resulting residue is used for other determinations.
The determination of other groups of analytes described in ISO 21068, Parts 1 to 4, are free metals,
free silicon (Si ), free aluminium (Al ), free magnesium (Mg ), free iron (Fe ) and the group of
free free free free
oxides from main to trace components.
ISO 21068, Parts 1 to 4, also describe the determination of silicon dioxide, total silicon, oxygen and
nitrogen and other oxide bound metals that typically occur in the materials.
It represents a listing of analytical methods which is generally structured according to material
composition. However, it is still the user who should prove the applicability of the method depending on
the material and analytical requirements.
The most broadly used analytical techniques such as X-ray fluorescence spectroscopy (XRF) and
inductively coupled plasma-optical emission spectrometry (ICP-OES) suffer from the disadvantage that
the analytical results are chemical species independent. For carbon-containing ceramic raw materials
and compositions ISO 21068, Parts 1 to 4, provide analytical methods for the determination of free
carbon, and SiC in the presence of oxide compounds in particular SiO .
2
Due to the diversity of laboratory equipment, the four parts of ISO 21068 summarize broadly used
analytical techniques which lead to equivalent results. For example, the determination of carbon is
based in all described methods on the reaction of carbon with oxygen at elevated temperatures to CO .
2
Thus, carbon is analysed as CO .
2
As well as carbon and carbide compounds, metallic silicon, aluminium and magnesium are considered.
While metallic silicon is mainly a precursor material which remains after the production process of
SiC in the raw material, metallic aluminium is added as an antioxidant in carbon-containing refractory
formulations.
Mostly oxide bound components, such as Al O , CaO, MgO, TiO , Cr O , ZrO and alkalis, can be
2 3 2 2 3 2
determined by XRF, ICP-OES or wet chemical methods (see ISO 12677, ISO 26845, ISO 21587 Parts 1-3).
These results can be corrected by formulas provided by ISO 21068, Parts 1 to 4, in consideration of the
values obtained by the determination of carbon, SiC, and metallic components.
ISO 21068, Parts 1 to 4, also provide methods for qualitative and quantitative determinations of the
nitrogen content and the determination of oxygen. Thereby only the total content of nitrogen and
oxygen is given; a precise determination of non-carbide components (oxides and nitrides) is not possible
in this way.
vi
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oSIST prEN ISO 21068-2:2023
ISO/DIS 21068-2:2023(E)
ISO 21068, Parts 1 to 4, also provide methods to distinguish quantitatively between different varieties
of nitrides like silicon nitride, silicon oxy-nitride and sialon.
vii
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oSIST prEN ISO 21068-2:2023
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oSIST prEN ISO 21068-2:2023
DRAFT INTERNATIONAL STANDARD ISO/DIS 21068-2:2023(E)
Chemical analysis of raw materials and refractory products
containing silicon-carbide, silicon-nitride, silicon-
oxynitride and sialon —
Part 2:
Determination of volatile components, total carbon, free
carbon, silicon carbide, total and free silicon, free and
surface silica
1 Scope
This part of ISO 21068 specifies analytical techniques for the determination of volatile components by
thermal treatment at specified temperatures, and methods for the determination of the total carbon
content, free carbon, silicon carbide, total and free silicon and free and surface silica content of silicon-
carbide, silicon-nitride and silicon-oxynitride containing raw materials and refractory products.
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 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 9286, Abrasive grains and crude — Chemical analysis of silicon carbide
ISO 12677, Chemical analysis of refractory products by X-ray fluorescence (XRF) — Fused cast-bead method
ISO 20565-1, Chemical analysis of chrome-bearing refractory products and chrome-bearing raw materials
(alternative to the X-ray fluorescence method) — Part 1: Apparatus, reagents, dissolution and determination
of gravimetric silica
ISO 20565-2, Chemical analysis of chrome-bearing refractory products and chrome-bearing raw materials
(alternative to the X-ray fluorescence method) — Part 2: Wet chemical analysis
ISO 20565-3, Chemical analysis of chrome-bearing refractory products and chrome-bearing raw materials
(alternative to the X-ray fluorescence method) — Part 3: Flame atomic absorption spectrometry (FAAS)
and inductively coupled plasma atomic emission spectrometry (ICP-AES)
ISO 21068-1, Chemical analysis of raw materials and refractory products containing silicon-carbide, silicon-
nitride, silicon-oxynitride and sialon — Part 1: General information and sample preparation
ISO 21079-1, Chemical analysis of refractories containing alumina, zirconia and silica — Refractories
containing 5 percent to 45 percent of ZrO (alternative to the X-ray fluorescence method) — Part 1:
2
Apparatus, reagents and dissolution
ISO 21079-2, Chemical analysis of refractories containing alumina, zirconia, and silica — Refractories
containing 5 percent to 45 percent of ZrO (alternative to the X-ray fluorescence method) — Part 2: Wet
2
chemical analysis
ISO 21079-3, Chemical analysis of refractories containing alumina, zirconia, and silica — Refractories
containing 5 percent to 45 percent of ZrO (alternative to the X-ray fluorescence method) — Part 3: Flame
2
1
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oSIST prEN ISO 21068-2:2023
ISO/DIS 21068-2:2023(E)
atomic absorption spectrophotometry (FAAS) and inductively coupled plasma emission spectrometry (ICP
-AES)
ISO 21587-1, Chemical analysis of aluminosilicate refractory products (alternative to the X-ray fluorescence
method) — Part 1: Apparatus, reagents, dissolution and gravimetric silica
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 c
...
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