oSIST prEN ISO 3262-20:2020

SLOVENSKI STANDARD
oSIST prEN ISO 3262-20:2020
01-marec-2020

Polnila - Specifikacije in preskusne metode - 20. del: Pirogeni silicijev dioksid

Extenders - Specifications and methods of test - Part 20: Fumed silica (ISO/DIS 3262-

Matières de charge - Spécifications et méthodes d'essai - Partie 20: Silice pyrogénée

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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

Foreword ........................................................................................................................................................................................................................................iv

1  Scope ................................................................................................................................................................................................................................. 1

2  Normative references ...................................................................................................................................................................................... 1

3  Terms and definitions ..................................................................................................................................................................................... 1

4  Requirements and test methods .......................................................................................................................................................... 2

5  Sampling ........................................................................................................................................................................................................................ 2

6  Determination of silica content ............................................................................................................................................................ 2

6.1 Principle ........................................................................................................................................................................................................ 2

6.2 Reagents........................................................................................................................................................................................................ 3

6.3 Apparatus .................................................................................................................................................................................................... 3

6.4 Procedure .................................................................................................................................................................................................... 3

6.5 Expression of results .......................................................................................................................................................................... 4

6.6 Precision ....................................................................................................................................................................................................... 4

contents by spectrometry ........................................................................................................................................................................... 4

7.1 Principle ........................................................................................................................................................................................................ 4

7.2 Reagents and materials ................................................................................................................................................................... 4

7.3 Apparatus .................................................................................................................................................................................................... 5

7.4 Procedure .................................................................................................................................................................................................... 6

7.5 Expression of results .......................................................................................................................................................................... 8

7.6 Precision ....................................................................................................................................................................................................... 8

8  Determination of carbon content ....................................................................................................................................................... 9

8.1 Principle ........................................................................................................................................................................................................ 9

8.2 Reagents and materials ................................................................................................................................................................... 9

8.3 Apparatus .................................................................................................................................................................................................... 9

8.4 Procedure .................................................................................................................................................................................................10

8.5 Expression of results .......................................................................................................................................................................10

8.6 Precision ....................................................................................................................................................................................................10

9  Determination of chloride content .................................................................................................................................................11

9.1 Principle .....................................................................................................................................................................................................11

9.2 Reagents.....................................................................................................................................................................................................11

9.3 Apparatus .................................................................................................................................................................................................11

9.4 Procedure .................................................................................................................................................................................................11

9.5 Expression of results .......................................................................................................................................................................12

9.6 Precision ....................................................................................................................................................................................................12

10  Test report ................................................................................................................................................................................................................12

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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

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).

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Any trade name used in this document is information given for the convenience of users and does not

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World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

This document was prepared by Technical Committee ISO/TC 256, Pigments, dyestuff and extenders.

This second edition cancels and replaces the first edition (ISO 3262-20:2000), which has been

— in Table 1 carbon content has been revised and organic surface has been refined;

— the text has been editorially revised and the normative references have been updated.

Any feedback or questions on this document should be directed to the user’s national standards body. A

This document specifies requirements and corresponding methods of test for fumed silica.

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 787-2, General methods of test for pigments and extenders — Part 2: Determination of matter volatile

ISO 787-9, General methods of test for pigments and extenders — Part 9: Determination of pH value of an

ISO 787-11, General methods of test for pigments and extenders — Part 11: Determination of tamped

ISO 787-18, General methods of test for pigments and extenders — Part 18: Determination of residue on

ISO 3262-1, Extenders for paints — Specifications and methods of test — Part 1: Introduction and general

ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling

ISO 18451-1, Pigments, dyestuffs and extenders — Terminology — Part 1: General terms

For the purposes of this document, the terms and definitions given in ISO 18451-1 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

amorphous silica produced from silicon halides by high-temperature flame hydrolysis

For fumed silica complying with this document, the essential requirements are specified in Table 1 and

A test portion is ignited, weighed and treated with sulphuric acid and hydrofluoric acid. The silicon

tetrafluoride thus formed is evaporated off and the silica content is calculated from the impurities is

Use only reagents of recognized analytical grade and only water of at least grade 3 purity as defined in

Add 1 part by volume of concentrated sulphuric acid, approximately 96 % (mass fraction) ρ ≈ 1,84 g/ml,

6.2.2  Hydrofluoric acid, concentrated, approximately 40 % (mass fraction) ρ ≈ 1,13 g/ml.

Weigh, to the nearest 0,2 mg, approximately 1 g (m ) of the sample (see Clause 5) into the tared platinum

Ignite the test portion in the muffle furnace (6.3.2) at (1 000 ± 20) °C to constant mass (this should take

approximately 2 h) and allow to cool in the desiccator (6.3.4). Weigh the test portion again (m ).

Wet the ignited test portion in the platinum dish with 2 ml to 3 ml of water, add 1 ml of sulphuric acid

(6.2.1) and 15 ml of hydrofluoric acid (6.2.2) and evaporate to a syrup on the infrared evaporator (6.3.3),

taking care to avoid loss by spitting. Allow to cool and wash the sides down with small quantities of water.

Then add a further 10 ml of hydrofluoric acid and evaporate to dryness. If the evaporation of the silicon

tetrafluoride is not complete, add a further 10 ml of hydrofluoric acid and evaporate to dryness again.

Heat the residue until white fumes are no longer evolved, then ignite for 30 min in the muffle furnace

at (1 000 ± 20) °C. Remove from the furnace, allow to cool in the desiccator and weigh to the nearest

Calculate the silica content w (SiO ), expressed as a percentage mass fraction, using Formula (1):

Calculate the mean of the two determinations and report the result to the nearest 0,1 %.

A test portion is treated with sulphuric acid and hydrofluoric acid in a platinum dish. The resulting

silicon tetrafluoride is volatized and the residue is dissolved in hydrochloric acid. After diluting with