prEN ISO 17947-1

SLOVENSKI STANDARD
01-marec-2026
Fina keramika (sodobna keramika, sodobna tehnična keramika) - Metode za
kemijsko analizo finih praškov silicijevega nitrida - 1. del: Mokre kemijske metode,
rentgenska fluorescenca (XRF) z metodo taljenih krogel, vroča ekstrakcija z
nosilnim plinom (CGHE) in metode zgorevanja (ISO/DIS 17947-1:2025)
Fine ceramics (advanced ceramics, advanced technical ceramics) - Methods for
chemical analysis of silicon nitride powders - Part 1: Wet chemical methods, X-ray
fluorescence (XRF) using the fused cast-bead method, carrier-gas hot extraction
(CGHE) and combustion methods (ISO/DIS 17947-1:2025)
Hochleistungskeramik - Verfahren zur chemischen Analyse von Pulvern aus
Siliciumnitrid - Teil 1: Nasschemische Verfahren, Röntgenfluoreszenzanalyse (RFA)
unter Anwendung des Schmelzaufschluss-Verfahrens, Trägergasheißextraktion (CGHE)
und Verbrennungsverfahren (ISO/DIS 17947-1:2025)
Céramiques techniques - Méthodes pour l'analyse chimique de poudres fines de nitrure
de silicium - Partie 1: Titre manque (ISO/DIS 17947-1:2025)
Ta slovenski standard je istoveten z: prEN ISO 17947-1
ICS:
81.060.30 Sodobna keramika Advanced ceramics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 17947-1
ISO/TC 206
Fine ceramics (advanced ceramics,
Secretariat: JISC
advanced technical ceramics) —
Voting begins on:
Methods for chemical analysis of
2025-12-30
silicon nitride powders —
Voting terminates on:
2026-03-24
Part 1:
Wet chemical methods, X-ray
fluorescence (XRF) using the fused
cast-bead method, carrier-gas hot
extraction (CGHE) and combustion
methods
ICS: 81.060.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
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INTERNATIONAL STANDARD UNTIL
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Reference number
ISO/DIS 17947-1:2025(en)
DRAFT
ISO/DIS 17947-1:2025(en)
International
Standard
ISO/DIS 17947-1
ISO/TC 206
Fine ceramics (advanced ceramics,
Secretariat: JISC
advanced technical ceramics) —
Voting begins on:
Methods for chemical analysis of
silicon nitride powders —
Voting terminates on:
Part 1:
Wet chemical methods, X-ray
fluorescence (XRF) using the fused
cast-bead method, carrier-gas hot
extraction (CGHE) and combustion
methods
ICS: 81.060.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
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Published in Switzerland Reference number
ISO/DIS 17947-1:2025(en)
ii
ISO/DIS 17947-1:2025(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Analytes and ranges . 2
4 Preparation of test sample . 2
4.1 General .2
4.2 Sampling .2
4.3 Drying .2
4.4 Weighing .2
5 Apparatus and reagents . 2
6 Blank test . 2
7 Determination of silicon . 3
7.1 Classification of determination methods .3
7.2 Fusion‑dehydration/insolubilization separation‑gravimetry and ICP‑OES .3
7.2.1 Principle .3
7.2.2 Reagents .3
7.2.3 Apparatus and instruments .3
7.2.4 Procedure .4
7.2.5 Blank test .4
7.2.6 Calibration . . .4
7.2.7 Calculation .5
7.3 XRF using fused cast‑bead method .5
8 Determination of nitrogen . 5
8.1 Classification of determination methods .5
8.2 Acid pressure decomposition‑distillation separation‑acidimetric titration method .5
8.3 Inert gas fusion‑thermal conductivity method .10
8.4 Fusion‑ammonia separation‑acidimetric titration method . 12
9 Determination of aluminium, iron, and calcium .13
9.1 Principle . 13
9.2 Reagents . 13
9.3 Apparatus and instrument . 13
9.4 Procedure .14
9.5 Blank test .14
9.6 Calibration .14
9.7 Calculation .14
10 Determination of oxygen.15
10.1 Principle . 15
10.2 Reagents . 15
10.3 Apparatus . 15
10.4 Instrument . 15
10.5 Procedure . 15
10.6 Blank test . 15
10.7 Calculation of calibration coefficient . 15
10.8 Calculation .16
11 Determination of carbon . 16
11.1 Classification of determination methods .16
11.2 Combustion (induction furnace)‑IR absorption spectrometry .17
11.2.1 Principle .17
11.2.2 Reagents .17

iii
ISO/DIS 17947-1:2025(en)
11.2.3 Apparatus .17
11.2.4 Instrument .17
11.2.5 Procedure .18
11.2.6 Blank test .18
11.2.7 Calculation of calibration coefficient .18
11.2.8 Calculation .19
11.3 Combustion (resistance furnace)‑coulometry .19
11.4 Combustion (resistance furnace)‑thermal conductivity.19
12 Determination of fluorine and chlorine. 19
12.1 Principle .19
12.2 Reagents .19
12.3 Apparatus and instruments. 20
12.4 Procedure . 20
12.4.1 Extraction of fluorine and chlorine from the sample . 20
12.4.2 Determination of fluorine and chlorine . 20
12.5 Blank test .21
12.6 Calibration .21
12.7 Calculation .21
13 Reporting analytical values .22
13.1 Number of analyses . 22
13.2 Evaluation of analytical values . 22
13.3 Expression of analytical values . 22
14 Test report .22
Annex A (informative) List of commercial certified reference materials .23
Annex B (informative) Analytical results obtained from a round robin test .24
Annex C (informative) Spectral lines for ICP-OES .28
Bibliography .29

iv
ISO/DIS 17947-1:2025(en)
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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO's adherence to the WTO principles in the Technical Barriers to Trade (TBT)
see the following URL: Foreword ‑ Supplementary information
The committee responsible for this document is ISO/TC 206, Fine ceramics.

v
ISO/DIS 17947-1:2025(en)
Introduction
This International Standard has been developed from Japanese Industrial Standard JIS R 1603:2007 with
reference to CEN ENV 14226:2002 and ASTM C1494‑01:2007, and is applicable to the chemical analysis of
silicon nitride raw powders for fine ceramics use. This International Standard covers both major and minor
constituents such as silicon, nitrogen, and some of trace metallic and non‑metallic elements.

vi
DRAFT International Standard ISO/DIS 17947-1:2025(en)
Fine ceramics (advanced ceramics, advanced technical
ceramics) — Methods for chemical analysis of silicon nitride
powders —
Part 1:
Wet chemical methods, X-ray fluorescence (XRF) using the
fused cast-bead method, carrier-gas hot extraction (CGHE)
and combustion methods
1 Scope
This International Standard specifies the methods for the chemical analysis of silicon nitride powders used
as raw material for fine ceramics.
This International Standard stipulates the determination methods of silicon, nitrogen, aluminium, iron,
calcium, oxygen, carbon, fluorine, and chlorine in silicon nitride powders.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 2828, Aluminium oxide primarily used for the production of aluminium — Determination of fluorine content
— Alizarin complexone and lanthanum chloride spectrophotometric method
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 6353-1, Reagents for chemical analysis — Part 1: General test methods
ISO 6353-2, Reagents for chemical analysis — Part 2: Specifications — First series
ISO 6353-3, Reagents for chemical analysis — Part 3: Specifications — Second series
ISO 8656-1, Refractory products — Sampling of raw materials and unshaped products — Part 1: Sampling scheme
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
ISO 21068-3, 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 21438-2, Workplace atmospheres — Determination of inorganic acids by ion chromatography — Part 2:
Volatile acids, except hydrofluoric acid (hydrochloric acid, hydrobromic acid and nitric acid)
ISO 21438-3, Workplace atmospheres — Determination of inorganic acids by ion chromatography — Part 3:
Hydrofluoric acid and particulate fluorides
ISO 26845, Chemical analysis of refractories — General requirements for wet chemical analysis, atomic absorption
spectrometry (AAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) methods

ISO/DIS 17947-1:2025(en)
3 Analytes and ranges
Analytes and ranges specified in this International Standard shall be as follows.
a) Silicon (Si), range of 30 % to 70 % (mass fraction)
b) Nitrogen (N), range of 30 % to 45 % (mass fraction)
c) Aluminium (Al), range of 0,001 % to 0,6 % (mass fraction)
d) Iron (Fe), range of 0,001 % to 0,6 % (mass fraction)
e) Calcium (Ca), range of 0,001 % to 0,03 % (mass fraction)
f) Oxygen (O), range of 0,05 % to 5 % (mass fraction)
g) Carbon (C), range of 0,01 % to 6 % (mass fraction)
h) Fluorine (F), range of 0,001 % to 0,2 % (mass fraction)
i) Chlorine (Cl), range of 0,001 % to 0,2 % (mass fraction)
4 Preparation of test sample
4.1 General
The method of preparing samples shall be in accordance with ISO 8656‑1 unless otherwise mutually agreed
upon between the analyser and the customer.
4.2 Sampling
Take the sample in accordance with ISO 8656‑1.
4.3 Drying
Take about 10 g of the sample into a flat‑type weighing bottle (60 mm × 30 mm) and spread it uniformly over
the bottom of the bottle. Place the bottle in a drying oven at 110 °C ± 5 °C for 2 h without a lid, and then cool
in a desiccator (desiccant: magnesium perchlorate for drying) with a lid for 1 h.
4.4 Weighing
Weigh the sample of the required quantity to the nearest 0,1 mg using a balance.
5 Apparatus and reagents
Unless otherwise specified in each determination, use ordinary laboratory apparatus for chemical analysis
listed in ISO 26845, Clause 4, as necessary. Reagents should conform to the requirements of ISO 6353‑1,
ISO 6353‑2, and ISO 6353‑3, as appropriate. Unless otherwise specified in each determination, use
corresponding reagents of analytical grade listed in ISO 26845, Clause 5, as necessary.
6 Blank test
Blank test shall be carried out by using identical quantities of reagents, conditions, and procedures
throughout each determination to correct the analytical values obtained.

ISO/DIS 17947-1:2025(en)
7 Determination of silicon
7.1 Classification of determination methods
Silicon shall be determined by either of the following methods. If analytical results with four figures are required,
use the method A. If analytical results with two or three figures are required, the method B can be used.
— Method A: Fusion–dehydration/insolubilization separation–gravimetry and inductively coupled plasma
optical emission spectrometry (ICP‑OES)
— Method B: XRF using fused cast‑bead method
7.2 Fusion-dehydration/insolubilization separation-gravimetry and ICP-OES
7.2.1 Principle
A sample is fused with alkaline carbonate and the melt is treated with an acid to separate into two parts of
silicon, insoluble silicon and soluble silicon, by filtration. Insoluble silicon is determined using gravimetry as
silicon dioxide converted after ignition, whereas soluble silicon in the filtrate is determined using ICP‑OES.
The sum of them represents the content of silicon in the sample.
7.2.2 Reagents
Reagents of analytical grade shall be used. Reagent solutions shall be preserved in plastic bottles.
7.2.2.1 Water, of grade 1 or superior specified in ISO 3696.
7.2.2.2 Sodium carbonate, Na CO , anhydrous, specified in ISO 6353‑3 or that of higher grade.
2 3
7.2.2.3 Hydrochloric acid (1+1), (1+4), (1+50), HCl, concentrated hydrochloric acid (c(HCl) = 32 %, mass
fraction) diluted (1+1), (1+4) and (1+50) by volume with water (7.2.2.1).
7.2.2.4 Sulfuric acid (1+1), (1+4), H SO , concentrated sulfuric acid (c(H SO ) = 96 %, mass fraction)
2 4 2 4
diluted (1+1) and (1+4) by volume with water (7.2.2.1).
7.2.2.5 Cellulose powder.
7.2.2.6 Polyethylene glycol (PEG) solution, (C H O) H O, 0,05 % mass fraction of PEG, prepared by
2 4 n 2
dissolving solid PEG in water (7.2.2.1).
7.2.2.7 Hydrofluoric acid, HF, c(HF) = 48 %, mass fraction.
7.2.3 Apparatus and instruments
Use ordinary laboratory apparatus and instruments for chemical analysis in accordance with ISO 26845,
Clause 4.
7.2.3.1 Platinum dish.
7.2.3.2 Platinum crucible.
7.2.3.3 Burner, capable of heating at 1 100 °C.
7.2.3.4 Muffle furnace, capable of being operated at 1 100 °C.

ISO/DIS 17947-1:2025(en)
7.2.3.5 Balance, readable to 0,1 mg.
7.2.3.6 Inductively coupled plasma optical emission spectrometer (ICP-OES).
7.2.4 Procedure
7.2.4.1 General
The procedure shall be as follows. The procedure described in ISO 21068‑2, Clause 8 can be alternatively used.
7.2.4.2 Fusion of sample
Weigh 0,30 g of the sample and 2,0 g of sodium carbonate, anhydrous, into a platinum dish and mix well.
Start to heat carefully and increase the temperature gradually to 1 000 °C to completely fuse the sample
using a burner or in a muffle furnace.
7.2.4.3 Separation of silicon
Add 20 ml of hydrochloric acid (1+1) to dissolve the melt on a hot plate. Silicon dioxide will appear to be
jellified and precipitated at this stage. There are two methods to separate the precipitated silicon dioxide.
a) Dehydrate carefully the precipitate to dryness in order to prevent it from spattering and add 5 ml of
hydrochloric acid (1+1) and 20 ml of water to dissolve any salt mixed with the precipitate. Filtrate the
precipitate with a filter paper and wash with hot hydrochloric acid (1+50) several times and then with
hot water sufficiently until it contains no salt. Receive the filtrate and washings together in a volumetric
flask and make constant volume. Preserve this precipitate for gravimetry of insoluble silicon and the
solution for the ICP‑OES determination of soluble silicon, respectively.
b) After formation of jellified silicon dioxide, add 0,05 g of cellulose powder and 10 ml of PEG solution
(7.2.2.6) to agglomerate silicon dioxide for easy filtration. Filtrate and wash in the same procedure,
and then preserve this precipitate for gravimetry of insoluble silicon and the solution for the ICP‑OES
determination of soluble silicon, respectively.
7.2.4.4 Gravimetry for insoluble silicon
Transfer the filter paper with the precipitate to a platinum crucible. Heat the platinum crucible slowly using
a burner (7.2.3.3) or in a muffle furnace (7.2.3.4) until complete ashing of the filter paper and then calcine
the residue at 1 100 °C. Place the platinum crucible in a desiccator to cool to room temperature. Weigh the
platinum crucible. Moisten the residue in the platinum crucible with a few drops of water (7.2.2.1) and
sulfuric acid (1+1) (7.2.2.4) and add 10 ml of hydrofluoric acid (7.2.2.7). Then evaporate to dryness on a hot
plate to remove all silicon dioxide, calcine the residue at 1 100 °C using a burner or in a muffle furnace and
place the platinum crucible in a desiccator to cool to room temperature. Weigh the platinum crucible again.
The loss of mass after hydrofluoric acid treatment corresponds to the amount of insoluble silicon dioxide.
7.2.4.5 ICP-OES for soluble silicon
Aspirate the test solution obtained in 7.2.4.3 into an Ar plasma of ICP‑OES to determine soluble silicon in
the sample.
7.2.5 Blank test
Run blank determinations according to the operations of 7.2.4.2 to 7.2.4.5 without taking a sample.
7.2.6 Calibration
For ICP‑OES, prepare calibration solutions to span the range of concentration of silicon in the test solution.
Each calibration solution shall have a similar matrix to the test solution.

ISO/DIS 17947-1:2025(en)
With those calibration solutions, create the calibration function for soluble silicon to establish the relation
between the measured emission intensity and the concentration of silicon in the test solution.
7.2.7 Calculation
With the amount of insoluble silicon in 7.2.4.4, soluble silicon in 7.2.4.5 and the blank test in 7.2.5, calculate
the content of silicon according to Formula (1).
vA × −A
100  () 
wS()i =× ()mm− × 0,4674 + (1)
 
m
 
where
w(Si) is the mass fraction of silicon in the sample, in percent;
m is the mass of insoluble silicon dioxide in the sample (7.2.4.4), in grams;
m is the mass of insoluble silicon dioxide in the blank test (7.2.5), in grams;
A is the concentration of soluble silicon in the test solution (7.2.4.3), in milligrams per litre;
A is the concentration of soluble silicon in the blank solution (7.2.5), in milligrams per litre;
V is the volume of the test and blank solution, in millilitres;
m is the mass of the sample (7.2.4.2), in grams.
7.3 XRF using fused cast-bead method
The procedure shall be in accordance with ISO 21068‑3, clause 8.2.
8 Determination of nitrogen
8.1 Classification of determination methods
Nitrogen shall be determined by either of the following methods. If analytical results with four figures are
required, use the method A or C. If two figures are required, the method B can be used.
— Method A: Acid pressure decomposition–distillation separation–acidimetric titration method
— Method B: Inert gas fusion–thermal conductivity method
— Method C: Fusion–ammonia separation–acidimetric titration method
8.2 Acid pressure decomposition-distillation separation-acidimetric titration method
8.2.1 Principle
A sample is decomposed in a pressure decomposition vessel with a mixture of hydrofluoric acid and sulfuric
acid to convert nitrogen into ammonia. Add boric acid and transfer the solution into a distillation flask. Add
sodium hydroxide and perform steam distillation. React the distilled ammonia with a known amount of
amidosulfuric acid and back‑titrate the excess of amidosulfuric acid with a standardized sodium hydroxide
solution.
8.2.2 Reagents
Reagents of analytical grade shall be used. Reagent solutions shall be preserved in plastic bottles.
8.2.2.1 Water, of grade 1 or superior specified in ISO 3696.
8.2.2.2 Hydrofluoric acid, HF, c(HF) = 48 %, mass fraction.

ISO/DIS 17947-1:2025(en)
8.2.2.3 Sulfuric acid (1+1), H SO , concentrated sulfuric acid (c(H SO ) = 96 %, mass fraction) diluted
2 4 2 4
(1+1) by volume with water (8.2.2.1).
8.2.2.4 Sodium hydroxide, NaOH, more than 97,0 % (mass fraction) of purity.
8.2.2.5 Sodium hydroxide solution (500 g/l), prepared by dissolving sodium hydroxide (8.2.2.4) in
water (8.2.2.1).
8.2.2.6 Amidosulfuric acid, H NO S, more than 99,0 % (mass fraction) of purity.
3 3
8.2.2.7 0,1mol/l amidosulfuric acid solution, prepared by weighing 10,0 g of amidosulfuric acid
(8.2.2.6) and dissolving in water (8.2.2.1) to make 1 000 ml. Calculate the factor of this solution according to
Formula (2).
F = m × P/(9,709 5 × 100) (2)
where
F is the factor of the 0,1 mol/l amidosulfuric acid solution;
m is the mass of amidosulfuric acid, g;
P is the purity of amidosulfuric acid, % (mass fraction).
8.2.2.8 0,1 mol/l sodium hydroxide solution, prepared by dissolving 4,0 g of sodium hydroxide (8.2.2.4)
in water (8.2.2.1) to make 1 000 ml.
Take exactly 50 ml of the 0,1 mol/l amidosulfuric acid solution in a beaker (200 ml) and dilute with water to
about 100 ml. Titrate this solution with the 0,1 mol/l sodium hydroxide solution using a pH meter. Take the
end point as pH 5,5 and determine the volume of the titrant consumed. Calculate the factor of this solution
according to Formula (3).
F = F × 50,00/V (3)
where
F is the factor of the 0,1 mol/l sodium hydroxide solution;
F is the factor of the 0,1 mol/l amidosulfuric acid solution;
V is the titration volume of the 0,1 mol/l sodium hydroxide solution, ml.
8.2.2.9 Boric acid, H BO .
3 3
8.2.2.10 Ammonium sulfate, (NH ) SO , more than 99,9 % (mass fraction) of purity.
4 2 4
8.2.3 Apparatus
Use ordinary laboratory apparatus for chemical analysis and the following.
8.2.3.1 Platinum crucible.
8.2.3.2 Pressure decomposition vessel, commercially available.
An example is shown in Figure 1. Use the vessels for the exclusive use in this analysis only to avoid cross‑
contamination by nitrogen. If the vessel which has ever contacted with nitric acid is used, the lower values of
nitrogen can be obtained.
8.2.3.3 Drying Oven, capable of heating at 160 °C ± 5 °C.

ISO/DIS 17947-1:2025(en)
8.2.3.4 Steam distillation apparatus, consisting of the components listed below. An example of the
apparatus is shown in Figure 2. Each component shall be made of hard glass coupled by common ground
joints and fixed by springs or clamps.
Dimensions in millimetres
Key
1 centre screw
2 screw cap
3 top plate
4 polytetrafluoroethylene (PTFE) cap
5 pressure vessel
6 PTFE vessel
7 bottom plate
Figure 1 — An example of sealed decomposition vessel

ISO/DIS 17947-1:2025(en)
Dimensions in millimetres
Key
a flask (2,5 l) for generation of steam
b trap (500 ml)
c sphere and tube
d distillation flask (750 ml)
e graham condenser
f receiver
1 funnel
2 ball joint
3 dumet wire
4 funnel with stopcock
5 rubber tube
6 13 to15 coils
7 small holes
8 electric heater
9 connection of rubber tube with pinchcock
10 jack
Figure 2 — An example of steam distillation apparatus
8.2.3.5 Steam generation flask (2,5 l), equipped with a funnel with a cock, a throw‑in heater (with 1 kW
Nichrome wire), and a steam outlet tube.

ISO/DIS 17947-1:2025(en)
8.2.3.6 Trap, the bottom of a bulb shall be connected to a rubber tube with a pinch cock for a drain.
The tip of steam leading‑out tube shall have several small holes.
8.2.3.7 Bulb, equipped with a steam leading‑in tube, a funnel with a cock, a splash‑proof trap, etc.
The steam leading‑in tube shall be cut in the middle enabling the exchange of the tip by connecting to a
rubber tube.
8.2.3.8 Distillation flask (750 ml).
8.2.3.9 Coiled condenser.
8.2.3.10 Receiver, a tall beaker (300 ml) shall be used.
8.2.3.11 pH meter, readable to the smallest value of 0,1 equipped with a glass electrode.
8.2.4 Procedure
a) Acid pressure decomposition of sample. Weigh 0,15 g of the sample in a platinum crucible (20 ml)
and add 5 ml of sulfuric acid (1+1) and 5 ml of hydrofluoric acid. Position the crucible into a pressure
decomposition vessel and close according to the manufacturer’s instructions. Place the vessel into a
drying oven and heat at 160 °C ± 5 °C for 16 h. Acid pressure decomposition under microwave irradiation
can be performed if available. For microwave sample decomposition the sample must be weighed into a
PTFE crucible or, if an antistatic device is available during weighing, directly into the PTFE vessel of the
decomposition system (see Figure 1).
b) Preparation of sample solution. After cooling, disassemble the vessel. Transfer the solution into a
100 ml plastic beaker by washing the crucible with water. Add 5 g of boric acid and mix well.
c) Preparation of steam distillation apparatus. After transferring the solution into a distillation flask,
assemble a distillation apparatus and add exactly 50 ml of the 0,1 mol/l amidosulfuric acid solution
to the receiver. Fix the coiled condenser so that the tip is immersed in the solution. Pour 50 ml of the
sodium hydroxide solution (500 g/l) through the funnel of the flask by washing the funnel with water,
make the solution volume about 150 ml and close the funnel cock.
d) Steam distillation. Perform the steam distillation with a steam flow of 4,5 ml to 5,0 ml per minute.
When the distillate reaches about 170 ml, lower the receiver to expose the tip of the condenser above
the liquid surface and continue distillation until the distillate reaches about 200 ml. Wash the outside of
the tip with a small amount of water. When using a new distillation apparatus or the apparatus which
has not been used for a long time, perform preliminary distillation for washing inside of it for 2 h to 3 h.
e) Titration. Titrate the distillate with the 0,1 mol/l sodium hydroxide solution using the pH meter. Take
the end point as pH 5,5 and record the volume of the titrant.
8.2.5 Recovery measurement
Weigh 0,280 g of ammonium sulfate to the nearest 0,1 mg in a platinum crucible (20 ml), perform operations
of 8.2.4 and calculate the recovery according to Formula (4). The recovery shall be not less than 99 %.

ISO/DIS 17947-1:2025(en)
R = [{(50,00 × F) – (V × F )} × 0,001 400 7/(m × 0,212 0)] × 100 (4)
where
R is the recovery, %;
F is the factor of the 0,1 mol/l amidosulfuric acid solution;
V is the titration volume of the 0,1 mol/l sodium hydroxide solution, ml;
F is the factor of the 0,1 mol/l sodium hydroxide solution;
m is the mass of ammonium sulphate, g.
8.2.6 Calculation
Calculate the content of nitrogen in the sample according to Formula (5).
w(N) = [{[(50,00 × F) – (V × F )] × [(0,001 400 7 × 100/R)]}/m] × 100 (5)
where
w(N) is the content of nitrogen in the sample, % (mass fraction);
F is the factor of the 0,1 mol/l amidosulfuric acid solution;
V is the titration volume of the 0,1 mol/l sodium hydroxide solution, ml;
F is the factor of the 0,1 mol/l sodium hydroxide solution;
R is the recovery (%) in 8.2.5;
m is the mass of the sample, g.
8.3 Inert gas fusion-thermal conductivity method
8.3.1 Principle
A sample is fused together with a flux in a graphite crucible under inert gas flow to extract nitrogen and
other gases from the sample. The elemental nitrogen is determined using a thermal conductivity detector
after the removal of concomitants such as carbon monoxide, carbon dioxide, other gases, and moisture.
8.3.2 Reagents
Reagents shall be as follows.
8.3.2.1 Helium, more than 99,99 % (volume fraction) of purity.
8.3.2.2 Flux, in shot or basket form made of tin or nickel. Use different metals for flux and capsule (8.3.3.1).
8.3.1 Apparatus
8.3.3.1 Capsule, made of nickel or tin designated for each apparatus.
8.3.3.2 Graphite crucible, suitable for the impulse furnace of the nitrogen analyser used.

ISO/DIS 17947-1:2025(en)
8.3.4 Instrument, a commercial nitrogen analyser is available
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