oSIST prEN ISO 21068-3:2023
(Main)Chemical analysis of raw materials and refractory products containing silicon-carbide, silicon-nitride, silicon-oxynitride and sialon - Part 3: Determination of nitrogen, oxygen and metallic and oxidic constituents (ISO/DIS 21068-3:2023)
Chemical analysis of raw materials and refractory products containing silicon-carbide, silicon-nitride, silicon-oxynitride and sialon - Part 3: Determination of nitrogen, oxygen and metallic and oxidic constituents (ISO/DIS 21068-3:2023)
This part of ISO 21068 specifies analytical techniques for the determination of total nitrogen and nitrogen calculated as silicon nitride, total oxygen, and metallic and oxidic components in silicon carbide raw materials and refractory products.
Chemische Analyse von Rohstoffen und feuerfesten Erzeugnissen, die Siliziumcarbid, Siliziumnitrid, Siliziumoxynitrid und Sialon enthalten - Teil 3: Bestimmung des Gehaltes an Stickstoff, Sauerstoff sowie metallischen und oxidischen Bestandteilen (ISO/DIS 21068-3:2023)
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 3: Dosage de l'azote, de l'oxygène et des constituants métalliques et oxydés (ISO/DIS 21068-3:2023)
Kemijska analiza surovin in ognjevzdržnih izdelkov, ki vsebujejo silicijev karbid, silicijev nitrid, silicijev oksinitrid in sialon - 3. del: Določevanje dušika, kisika ter kovinskih in oksidnih sestavin (ISO/DIS 21068-3:2023)
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN ISO 21068-3:2023
01-julij-2023
Nadomešča:
SIST EN ISO 21068-3:2008
Kemijska analiza surovin in ognjevzdržnih izdelkov, ki vsebujejo silicijev karbid,
silicijev nitrid, silicijev oksinitrid in sialon - 3. del: Določevanje dušika, kisika ter
kovinskih in oksidnih sestavin (ISO/DIS 21068-3:2023)
Chemical analysis of raw materials and refractory products containing silicon-carbide,
silicon-nitride, silicon-oxynitride and sialon - Part 3: Determination of nitrogen, oxygen
and metallic and oxidic constituents (ISO/DIS 21068-3:2023)
Chemische Analyse von Rohstoffen und feuerfesten Erzeugnissen, die Siliziumcarbid,
Siliziumnitrid, Siliziumoxynitrid und Sialon enthalten - Teil 3: Bestimmung des Gehaltes
an Stickstoff, Sauerstoff sowie metallischen und oxidischen Bestandteilen (ISO/DIS
21068-3:2023)
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
3: Dosage de l'azote, de l'oxygène et des constituants métalliques et oxydés (ISO/DIS
21068-3:2023)
Ta slovenski standard je istoveten z: prEN ISO 21068-3
ICS:
71.040.40 Kemijska analiza Chemical analysis
81.080 Ognjevzdržni materiali Refractories
oSIST prEN ISO 21068-3:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN ISO 21068-3:2023
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oSIST prEN ISO 21068-3:2023
DRAFT INTERNATIONAL STANDARD
ISO/DIS 21068-3
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 3:
Determination of nitrogen, oxygen and metallic and oxidic
constituents
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
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NATIONAL REGULATIONS.
ISO/DIS 21068-3:2023(E)
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oSIST prEN ISO 21068-3:2023
DRAFT INTERNATIONAL STANDARD
ISO/DIS 21068-3
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 3:
Determination of nitrogen, oxygen and metallic and oxidic
constituents
ICS: 81.080
This document is circulated as received from the committee secretariat.
COPYRIGHT PROTECTED DOCUMENT
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2023
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NATIONAL REGULATIONS.
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oSIST prEN ISO 21068-3:2023
ISO/DIS 21068-3:2023(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Determination of nitrogen and oxygen. 2
4.1 General . 2
4.2 Combined determination of nitrogen and oxygen by an analyser with thermal
conductivity (TC) and infrared (IR) absorption detection . 2
4.2.1 Principle . 2
4.2.2 Reagents . 3
4.2.3 Apparatus . 3
4.2.4 Nickel pre-treatment . 3
4.2.5 Calibration . . . 4
4.2.6 Procedure . 4
4.2.7 Precision . 5
4.3 Determination of total nitrogen content by fusion decomposition . 5
4.3.1 General . 5
4.3.2 Principle . 5
4.3.3 Reagents . 5
4.3.4 Apparatus . 5
4.3.5 Sample preparation . 7
4.3.6 Procedure . 7
4.3.7 Calculation and expression of results. 7
4.3.8 Precision . 8
4.4 Determination of total nitrogen content by Kjeldahl distillation . 8
4.4.1 Principle . 8
4.4.2 Reagents . 8
4.4.3 Apparatus . 9
4.4.4 Sample preparation . 9
4.4.5 Procedure . 9
4.4.6 Calculation and expression of results. 10
4.4.7 Precision . 10
4.5 Calculation of Si N content using total nitrogen content . 10
3 4
4.5.1 Calculation . 10
5 Determination of soluble iron by extraction with hydrochloric acid followed by
Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) .11
5.1 General . 11
5.2 Scope . . 11
5.3 Principle . 11
5.4 Apparatus . 11
5.5 Reagents . 11
5.6 Sample preparation . 11
5.7 Procedure . 11
5.8 Measurement .12
5.9 Calculation .12
6 Determination of metallic (free) aluminium by the hydrogen generating method .12
6.1 Principle . 12
6.2 Reagents . 13
6.3 Apparatus . 13
6.4 Sample preparation .13
6.5 Procedure . 13
iii
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oSIST prEN ISO 21068-3:2023
ISO/DIS 21068-3:2023(E)
6.6 Calculation and expression of results . 13
7 Determination of acid soluble aluminium and magnesium .14
7.1 General . 14
7.2 Reagents . 14
7.2.1 Hydrochloric acid, HCl, c(HCl) = 5 mol/l . 14
7.3 Procedure . 14
7.4 Measurement . 14
7.5 Precision . . . 14
8 Determination of elemental impurities in SiC raw materials .15
8.1 General . 15
8.1.1 Alkaline melt fusion . 15
8.1.2 Acid pressure decomposition. 17
8.2 Determination of impurities by XRF (fused bead method) . 18
8.3 Determination of impurities by DCArc OES (direct solid sampling method) . 18
9 Expression of results .18
10 Test report .18
Annex A (informative) Precision data .19
Bibliography .23
iv
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oSIST prEN ISO 21068-3:2023
ISO/DIS 21068-3:2023(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 21068-3 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 21068-3:2023
ISO/DIS 21068-3:2023(E)
Introduction
[8]
ISO 21068, Parts 1 to 4, have been developed from the combination of EN 12698:2007, Parts 1
[9] [10 to 12]
and 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 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 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.
This part of ISO 21068 is also applicable to the analysis of SiC raw materials.
Except the XRD method specified in Part 4 all chemical methods specified in this standard are only
[2] to [5]
validated for SiC raw materials. For refractory products classified in ISO 10081, Parts 1 to 4
[6]
(shaped) and ISO 1927-1 (unshaped) and raw materials containing carbon and/or silicon carbide this
standard apply after appropriate verification for any matrix composition.
vi
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oSIST prEN ISO 21068-3:2023
DRAFT INTERNATIONAL STANDARD ISO/DIS 21068-3:2023(E)
Chemical analysis of raw materials and refractory products
containing silicon-carbide, silicon-nitride, silicon-
oxynitride and sialon —
Part 3:
Determination of nitrogen, oxygen and metallic and oxidic
constituents
1 Scope
This part of ISO 21068 specifies analytical techniques for the determination of total nitrogen and
nitrogen calculated as silicon nitride, total oxygen, and metallic and oxidic components in silicon
carbide 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 10058-1, Chemical analysis of magnesite and dolomite refractory products (alternative to the X-ray
fluorescence method) — Part 1: Apparatus, reagents, dissolution and gravimetric silica
ISO 10058-2, Chemical analysis of magnesite and dolomite refractory products (alternative to the X-ray
fluorescence method) — Part 2: Wet chemical analysis
ISO 10058-3, Chemical analysis of magnesite and dolomite refractory products (alternative to the X-ray
fluorescence method) — Part 3: Flame atomic absorption spectrometry (FAAS) and inductively coupled
plasma emission spectrometry (ICP-OES)
ISO 12677, Chemical analysis of refractory products by XRF — Fused cast bead method
ISO 16169, Preparation of silicon carbide and similar materials for analysis by ISO 12677
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 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 emission spectrometry (ICP-OES)
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 21068-2, 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
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oSIST prEN ISO 21068-3:2023
ISO/DIS 21068-3:2023(E)
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
atomic absorption spectrometry (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 coupled plasma and atomic absorption spectrometry methods
EN 15979, Testing of ceramic raw and basic materials – Direct determination of mass fractions of impurities
in powders and granules of silicon carbide by OES by DC arc excitation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 21068-1 shall apply.
4 Determination of nitrogen and oxygen
4.1 General
For oxygen only the inert-gas fusion method is given; for nitrogen, calculated usually as Si N several
3 4
different methods are described.
NOTE The calculation of nitrogen as Si N is only applicable in the case where other nitride species are
3 4
absent or too low to detect by XRD, see ISO 21068-1. Otherwise, nitrogen is reported as total nitrogen.
4.2 Combined determination of nitrogen and oxygen by an analyser with thermal
conductivity (TC) and infrared (IR) absorption detection
4.2.1 Principle
The method uses inert-gas fusion analysis. A pre-weighed sample is placed in a graphite crucible
positioned between the electrodes of an impulse furnace. Typically, 5 kW of power is passed through
the crucible generating a temperature of approximately 2 800 °C.
NOTE 1 Furnace temperatures can be varied by increasing and decreasing current/voltage.
The sample decomposes, releasing any oxygen and nitrogen present. The nitrogen released remains
as elemental nitrogen, while oxygen combines with the carbon of the graphite crucible to form carbon
monoxide. The sample gases are carried on a helium carrier gas either to a copper oxide catalyst,
which converts carbon monoxide to carbon dioxide, and then to an infrared absorption cell which
measures the carbon dioxide present or are measured directly without catalyst as carbon monoxide.
The gas stream is then passed through sodium hydroxide to remove carbon dioxide, and magnesium
perchlorate to remove any moisture present, and finally through a thermal conductivity cell to quantify
the nitrogen.
2
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oSIST prEN ISO 21068-3:2023
ISO/DIS 21068-3:2023(E)
Because the sample will invariably be in the form of a powder, it should be enclosed in a small tin
capsule before placing it in the graphite crucible to prevent any loss of sample during analysis.
For materials difficult to decompose, a fluxing agent shall be added to the sample. A suitable agent is
oxygen free nickel capsule or nickel wire basket.
4.2.2 Reagents
Only chemicals the analytical purity of which is known and sufficient for the analytical purpose, as well
as distilled water or water which has been completely deionized by means of an ion exchange process
shall be used.
4.2.2.1 Tin capsule, of suitable dimensions and oxygen and nitrogen free.
4.2.2.2 High temperature graphite crucibles, of suitable size, recommended by the instrument
producer.
4.2.2.3 Nickel capsules or basket, of suitable dimensions and oxygen and nitrogen free.
4.2.2.4 Acetic acid, 96 wt%
4.2.2.5 Nitric acid, 65 wt%
4.2.2.6 Hydrochloric acid, 32 wt%
4.2.2.7 Acetone
4.2.2.8 Carbon dioxide, 99,998 % pure.
4.2.2.9 Nitrogen, 99,998 % pure.
4.2.2.10 Helium, 99,998 % pure.
4.2.3 Apparatus
Ordinary laboratory apparatus and the following.
4.2.3.1 Combined nitrogen/oxygen analyser, commercially available.
NOTE If no combined analyser for nitrogen and oxygen is available, a separate nitrogen and/or oxygen
analyser can be used.
4.2.3.2 Analytical balance, capable of measuring to the nearest 0,01 mg
4.2.4 Nickel pre-treatment
If nickel capsules or baskets are used, surface oxygen shall be removed by the following cleaning
procedure:
Prepare a solution containing approximately 75 ml of acetic acid (4.2.2.4), 25 ml of nitric acid (4.2.2.5)
and 1,5 ml of hydrochloric acid (4.2.2.6). In a well-ventilated fume cupboard, heat the solution to a
temperature of 55 °C ± 5 °C, immerse the nickel capsule or basket in the heated solution for 30 s to
60 s, remove the nickel capsule or basket from the solution and rinse immediately in running water.
Immerse the nickel capsule or basket in chemically pure acetone (4.2.2.7), dry thoroughly and place the
cleaned nickel capsules or basket in a desiccator.
3
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oSIST prEN ISO 21068-3:2023
ISO/DIS
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