SIST EN ISO 4938:2016

SLOVENSKI STANDARD
SIST EN ISO 4938:2016
01-maj-2016
1DGRPHãþD
SIST EN 24938:1997
SIST EN 24938:1997/AC:1997
-HNORLQåHOH]R'RORþHYDQMHQLNOMD*UDYLPHWULMVNDDOLWLWULPHWULMVNDPHWRGD,62

Steel and irons - Determination of nickel content - Gravimetric or titrimetric method (ISO
4938:2016)
Stahl und Eisen - Bestimmung des Nickelgehalts - Gravimetrisches oder titrimetrisches
Verfahren (ISO 4938:2016)
Aciers et fontes - Dosage du nickel - Méthode gravimétrique ou titrimétrique (ISO
4938:2016)
Ta slovenski standard je istoveten z: EN ISO 4938:2016
ICS:
77.040.30 Kemijska analiza kovin Chemical analysis of metals
77.080.01 Železne kovine na splošno Ferrous metals in general
SIST EN ISO 4938:2016 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 4938:2016

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SIST EN ISO 4938:2016


EN ISO 4938
EUROPEAN STANDARD

NORME EUROPÉENNE

March 2016
EUROPÄISCHE NORM
ICS 77.080.01 Supersedes EN 24938:1990
English Version

Steel and iron - Determination of nickel content -
Gravimetric or titrimetric method (ISO 4938:2016)
Aciers et fontes - Détermination du nickel - Méthode Stahl und Eisen - Bestimmung des Nickelanteils -
gravimétrique ou titrimétrique (ISO 4938:2016) Gravimetrisches oder titrimetrisches Verfahren (ISO
4938:2016)
This European Standard was approved by CEN on 21 November 2015.

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-CENELEC 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-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4938:2016 E
worldwide for CEN national Members.

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SIST EN ISO 4938:2016
EN ISO 4938:2016 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 4938:2016
EN ISO 4938:2016 (E)
European foreword
This document (EN ISO 4938:2016) has been prepared by Technical Committee ISO/TC 17 “Steel” in
collaboration with Technical Committee ECISS/TC 102 “Methods of chemical analysis for iron and steel”
the secretariat of which is held by SIS.
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 September 2016, and conflicting national standards
shall be withdrawn at the latest by September 2016.
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.
This document supersedes EN 24938:1990.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
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,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 4938:2016 has been approved by CEN as EN ISO 4938:2016 without any modification.
3

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SIST EN ISO 4938:2016

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SIST EN ISO 4938:2016
INTERNATIONAL ISO
STANDARD 4938
Second edition
2016-02-01
Steel and iron — Determination of
nickel content — Gravimetric or
titrimetric method
Aciers et fontes — Détermination du nickel — Méthode gravimétrique
ou titrimétrique
Reference number
ISO 4938:2016(E)
©
ISO 2016

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SIST EN ISO 4938:2016
ISO 4938:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

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SIST EN ISO 4938:2016
ISO 4938:2016(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Reagents . 1
5 Apparatus . 4
6 Sampling . 5
7 Procedure. 5
7.1 Test portion . 5
7.2 Determination . 5
7.2.1 Preparation of the test solution . 5
7.2.2 First nickel precipitation . 5
7.2.3 Second nickel precipitation . 6
7.2.4 Gravimetric determination . 7
7.2.5 Titrimetric determination . 7
8 Expression of results . 8
8.1 Methods of calculation . 8
8.1.1 Gravimetric determination . 8
8.1.2 Titrimetric determination . 8
8.2 Precision . 8
9 Test report . 9
Annex A (informative) Additional information on the international interlaboratory test.10
Annex B (informative) Graphical representation of precision data .11
Annex C (normative) Determination of nickel in combined filtrates by atomic
absorption spectrometry .13
Bibliography .16
© ISO 2016 – All rights reserved iii

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SIST EN ISO 4938:2016
ISO 4938:2016(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.
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 17, Steel, Subcommittee SC 1, Methods of
determination of chemical composition.
This second edition cancels and replaces the first edition (ISO 4938:1988), which has been
technically revised.
iv © ISO 2016 – All rights reserved

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SIST EN ISO 4938:2016
INTERNATIONAL STANDARD ISO 4938:2016(E)
Steel and iron — Determination of nickel content —
Gravimetric or titrimetric method
1 Scope
This International Standard specifies a method for the determination of nickel in steel and iron by
gravimetry or titrimetry.
The method is applicable to nickel contents from 1 % to 30 % (mass fraction).
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 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 4793, Laboratory sintered (fritted) filters — Porosity grading, classification and designation
ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical
composition
3 Principle
Dissolution of a test portion with appropriate acids.
Precipitation of the nickel as nickel-dimethylglyoxime.
— Cobalt, if present, is oxidized by potassium hexacyanoferrate(lll).
— Copper, if present with cobalt, preferably is removed by controlled potential electrolysis.
Acid dissolution of the precipitate and filtration of the solution, followed by a second precipitation of
the nickel as nickel dimethylglyoxime.
In the case of the gravimetric determination, weighing the dried dimethylglyoxime precipitate.
In the case of the titrimetric determination, acid dissolution of the precipitate, addition of excess EDTA.Na
2
solution and back titration of the excess EDTA.Na by zinc solution using xylenol orange as an indicator.
2
In both cases, determination of residual nickel in the filtrate(s) by atomic absorption spectrometry
(see Annex C).
4 Reagents
During the analysis, unless otherwise specified, use only reagents of recognized analytical grade and
only distilled grade 2 water as specified in ISO 3696 or water of equivalent purity.
4.1 Sodium hydrogen sulphate (NaHSO ).
4
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SIST EN ISO 4938:2016
ISO 4938:2016(E)

4.2 Ethanol, 95 % (volume fraction).
4.3 Acetic acid, glacial, ρ approximately 1,05 g/ml.
4.4 Hydrofluoric acid, ρ approximately 1,15 g/ml.
WARNING — Hydrofluoric acid is extremely irritating and corrosive to skin and mucous
membranes producing severe skin burns which are slow to heal. In case of contact with skin,
wash well with water, apply a topical gel containing 2,5 % (mass fraction) calcium gluconate and
seek immediate medical treatment.
4.5 Nitric acid, ρ approximately 1,40 g/ml.
4.6 Perchloric acid, ρ approximately 1,54 g/ml.
WARNING — Perchloric acid vapour can cause explosions in the presence of ammonia, nitrous
fumes or organic material in general.
4.7 Sulphuric acid, ρ approximately 1,84 g/ml.
4.8 Ammonia solution, ρ approximately 0,90 g/ml.
4.9 Hydrochloric acid, ρ approximately 1,19 g/ml, diluted 1 + 1.
Add 500 ml of hydrochloric acid (ρ approximately 1,19 g/ml) to 500 ml of water.
4.10 Hydrochloric acid, ρ approximately 1,19 g/ml, diluted 1 + 99.
Add 10 ml of hydrochloric acid (ρ approximately 1,19 g/ml) to 990 ml of water.
4.11 Nitric acid, ρ approximately 1,40 g/ml, diluted 2 + 3.
Add 200 ml of nitric acid (4.5) to 300 ml of water.
4.12 Perchloric acid, ρ approximately 1,54 g/ml, diluted 1 + 49.
Add 10 ml of perchloric acid (4.6) to 490 ml of water.
4.13 Ammonia solution, ρ approximately 0,90 g/ml, diluted 1 + 1.
Add 500 ml of ammonia solution (4.8) to 500 ml of water.
4.14 Ammonia solution, ρ approximately 0,90 g/ml, diluted 1 + 3.
Add 100 ml of ammonia solution (4.8) to 300 ml of water.
4.15 Hydrochloric/nitric acids mixture.
Mix three volumes of hydrochloric acid (ρ approximately 1,19 g/ml) with one volume of nitric acid (4.5).
Prepare this mixture immediately prior to use.
4.16 Ammonium acetate, 200 g/l solution.
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SIST EN ISO 4938:2016
ISO 4938:2016(E)

4.17 Ammonium citrate buffer solution.
Dissolve 500 g of citric acid monohydrate (C H O ·H O) in 675 ml of ammonia solution (4.8) and dilute
6 8 7 2
to 1 l with water.
Filter before use.
4.18 Citric acid, 500 g/l solution.
Dissolve 500 g of citric acid monohydrate (C H O ·H O) in water and dilute to 1 l with water.
6 8 7 2
Filter before use.
4.19 Dimethylglyoxime, 30 g/l solution in alkaline medium.
Dissolve 20 g of potassium hydroxide in 400 ml of water, add 30 g of dimethylglyoxime (C H N O ) and
4 8 2 2
stir until dissolution is complete. Dilute to 1 l with water and mix.
Filter before use.
4.20 Dimethylglyoxime, 10 g/l solution in ethanol.
Dissolve 10 g of dimethylglyoxime (C H N O ) in 1 000 ml of ethanol (4.2).
4 8 2 2
Filter before use.
4.21 Hydrazine dihydrogen sulphate (N H SO ), 100 g/l solution.
2 6 4
4.22 Potassium hexacyanoferrate(III), K [Fe(CN) ], 100 g/l solution.
3 6
This solution is stable for approximately 30 days.
1 ml of this solution corresponds approximately to 0,02 g of cobalt and manganese, respectively.
4.23 Washing water, adjusted to pH 8 with a few drops of ammonia solution (4.13).
4.24 Ethylenediaminetetraacetic acid disodium salt (EDTA.Na ), standard-volumetric solution.
2
4.24.1 Preparation of the solution
Dissolve 6,33 g of ethylenediaminetetraacetic acid disodium salt (C H O N Na ·2H O) in water,
10 14 8 2 2 2
transfer the solution to a 1 000 ml one-mark volumetric flask, dilute to the mark with water and mix.
1 ml of this standard solution corresponds approximately to 1 mg of nickel.
4.24.2 Standardization of the solution

Transfer 25,0 ml of the nickel standard solution (4.24.3) to a 250 ml beaker and add 33 ml of EDTA.Na
2
solution (4.24.1). Add 15 ml of ammonium acetate solution (4.16) and dilute to about 150 ml with water.
Continue as described in the third paragraph of 7.2.5.
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SIST EN ISO 4938:2016
ISO 4938:2016(E)

The corresponding concentration, c, of the EDTA.Na solution (4.24.1), expressed in milligrams of nickel
2
per millilitre, is given by Formula (1):
mm×25 +×V
() ()
12 1
c = (1)
V
2
where
m is the mass of nickel contained in 1 ml of the nickel standard solution (4.24.3), in milligrams;
1
m is the mass of nickel corresponding to 1 ml of the zinc standard solution (4.25), in milligrams;
2
V is the volume of the zinc standard solution (4.25) used for the titration, in millilitres;
1
V is the volume of the EDTA.Na solution (4.24.1) used for the standardization, in millilitres.
2 2
4.24.3 Nickel standard solution
Weigh, to the nearest 0,1 mg, 1,000 g of nickel [Ni > 99,95 % (mass fraction)]. Dissolve in 20 ml of
nitric acid (4.11). Boil to remove nitrous fumes, cool, transfer quantitatively to a 1 000 ml one-mark
volumetric flask, dilute to the mark with water and mix.
1 ml of this standard solution contains 1,0 mg of nickel.
4.25 Zinc standard solution.
Weigh, to the nearest 0,1 mg, 1,114 0 g of zinc [purity > 99,9 % mass fraction] and transfer to a 300 ml
beaker. If the zinc is oxidized, it should be cleaned with hydrochloric acid (4.9), water and acetone, and
dried for 5 min at 110 °C before use.
Add about 50 ml of water, 20 ml of hydrochloric acid (4.9) and five drops of bromine-saturated water.
Cover with a watch glass and heat until the metal is completely dissolved. Continue the heating until the
colour of the bromine disappears, cool to room temperature and add 20 ml of glacial acetic acid (4.3).
Adjust the pH of the solution to 6,0 ± 0,2 with ammonia solution (4.14). Transfer quantitatively to a
1 000 ml one-mark volumetric flask, dilute to the mark with water and mix.
1 ml of this standard solution corresponds to 1,0 mg of Ni and also approximately to 1 ml of the
EDTA.Na standard volumetric solution (4.24).
2
4.26 Xylenol orange, 1 g/l solution.
Pulverize 0,1 g of xylenol orange (C H N O SNa ) with a little portion of water to make a paste.
31 28 2 13 4
Dilute to 100 ml with water. Filter and store in a brown glass stoppere
...