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5437
STANDARD
Second edition
19924 2-l 5
Acid-grade and ceramic-grade fluorspar -
Determination of barium sulfate
- Gravimetric method
content
Spaths fluor pour Ia fabrication de I ’acide fluorh ydrique et spaths fluor
utilisables dans I ’industrie ckamique - Dosage du sulfate de baryum -
Methode gravim&rique
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ISO 5437:1992(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. Esch 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
(1 EC) on all matters of electrotechnical standardization.
International Standard ISO 5437 was prepared by Technical Committee
lSO/TC 175, Fluorspar.
This second edition cancels and replaces the first edition
(ISO 5437:1988), which has been updated.
0 ISO 1992
All rights reserved. No part of this publication may be reproduced or utilized in any ferm or
by any means, electronie or mechanical, including photocopying and microfilm, without per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-l 211 Geneve 20 l Switzerland
Printed in Switzerland
ii
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ISO 5437:1992(E)
INTERNATIONAL STANDARD
Acid-grade and ceramic-grade fluorspar -
Determination of barium sulfate content -
Gravimetric method
Filtration, drying and weighing of the residual barium
1 Scope
sulfate.
This International Standard specifies a gravimetric
method for the determination of the barium sulfate
4 Reagents
content of ,acid-grade and ceramic-grade fluorspar.
During the analysis, use only reagents of recognized
The method is applicable to products having barium
analytical grade and only distilled water or water of
sulfate contents equal to or greater than 0,l % (m/m)
.
equivalent purity.
I.
4.1 Hydrofluoric acid, Q approximately 1 ,13 g/ml,
2 Normative references
about 40 g/l Solution.
The following Standards contain provisions which,
WARNING - Very toxic by inhalation, in contact
through reference in this text, constitute provisions
with skin and if swallowed. Causes severe, burns.
of this International Standard. At the time of publica- ,” .1 1
. .
tion, the editions indicated were valid. All Standards
Keep Container tightly closed in a weil-ventilated
are subject to revision, and Parties to agreements
pläce. In case of contact with eyes, rinse imme-
based on this International Standard are encouraged
diately with plenty of water and seek lmedical ad-
to investigate the possibility of applying the most re-
vice. *’
1.
cent editions of the Standards indicated below.
Members of IEC and ISO maintain registers of cur-
Wear suitable protective clothing and gloves. In
rently valid International Standards.
case of accident or feeling unwell, seek medical
advice immediately (Show the label where poss-
ISO 565:1990, Test sieves - Metal wire cloth, per-
ible).
forated metal plate and electroformed sheet - Nom-
inal sizes of openings.
4.2 Sulfuric acid, Q approximately 1,84 g/ml, about
96 % !m/m) Solution.
ISO 8868: 1989, Fluorspar - Sampling and Sample
preparation.
4.3 Acid mixture.
Add 100 ml of hydrochloric acid [Q approximately
3 Principle
1 ,19 g/ml, about 38 % (IWLVZ) solution] to 500 ml of
water. Then carefully add 20 ml of the sulfuric acid
Evaporation to dryness of a test Portion in the pres-
(4.2), mix and dilute to 1 000 ml.
ence of hydrofluoric acid and concentrated sulfuric
acid. Extraction of the soluble salts from the residue
with a mixture of hydrochloric acid and sulfuric acid. 4.4 Ammonium acetate, 200 g/l solution.
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ISO 5437:1992(E)
Filter the contents of the beaker through the
a)
5 Apparatus
porcelain filter crucible (5.2) previously heated in
the furnace (5.6), maintained at 800 “C + 25 “C,
Ordinary laboratory apparatus and
cooled in a desiccator and weighed to the nearest
0,2 mg. Wash the contents of the porcelain
5.1 Platinum dish, of di
...