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UDC 667.622
IS0
O R G AN I ZATl O N FO R STAN DAR D I ZATl O N
I NTE R NAT1 O N AL
IS0 RECOMMENDATION
R 473
LITHOPONE
1st EDITION
February 1966
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 473, Lithopone, was drawn up by Technical Committee
ISO/TC 35, Paints, Varnishes and Related Products and their Raw Materials, the Secretariat of
which is held by the Nederlands Normalisatie-instituut ("1).
Work on this question by the Technical Committee began in 1950, taking into account
the studies which had been made by the former International Federation of the National Stand-
ardizing Associations (ISA), and led in 1960 to the adoption of a Draft IS0 Recommendation.
In April 1962, this Draft IS0 Recommendation (No. 484) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial
nature, by the following Member Bodies :
Au stria Italy Romania
Burma Japan Spain
Canada Netherlands Sweden
Chile New Zealand Switzerland
Czechoslovakia Portugal United Kingdom
Germany Republic of U.S.S.R.
India South Africa Yugoslavia
Two Member Bodies opposed the approval of the Draft:
Belgium
France
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Council, which decided, in February 1966, to accept it as an IS0 RECOMMENDATION.
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ISOlR 473 - 1966 (E)
IS0 Recommendation R 473 February 1966
LITHOPONE
1. SCOPE
This IS0 Recommendation establishes the more important requirements for lithopones and the
methods of test for these requirements.
2. DESCRIPTIONS
2.1 Lithopone 30%. A white pigment consisting of zinc sulphide (ZnS) and barium sulphate
(BaS04) in approximately molecular proportions. The material is a calcined Co-precipitate.
2.2 Lithopone bo”/* A white pigment which contains approximately 60% zinc sulphide (ZnS)
and a balance consisting mainly of barium sulphate (BaS04). The material is a calcined
Co-precipitate.
3. REQUIRED CHARACTERISTICS AND THEIR TOLERANCES
The lithopones should have the following characteristics :
I Clause
Properties Lithopone 30% 1 Lithopone 60% ~ describing
1 test method
Total zinc, calculated as zinc sulphide,
28 58 i 5.1
min. %
1 i 1 ~ 5.2
Zinc oxide, max. %
i
~ 5.1
Sum of total zinc, calculated as zinc sulphide
I
99 99 and
and barium sulphate, min. %
1 5.2
Barytes absent absent 1 5.3
Matter volatile at 105 OC, max.
0.5 0.5 I 5.4
%
Matter soluble in water, max. 0.5 ~ 0.5 i 5.5
%
.-
1
I
equal to an agreed
Alkalinity of the aqueous extract , 5.6
reference sample
I
Residue on sieve (63 pm), max. % o. I ~ o. 1 1 5.7
equal to an agreed
Colour I 5.8
reference sample
Lightening power ~ 5.9
as agreed between purchaser
Hiding power ~ 5.10
and vendor
~~
Oil absorption value 1 5.11
* There are on the market
(1) lithopones with a content of about 40 or 50 per cent zinc sulphide. These products should be marked so as to indicate
the zinc sulphide content,
(2) barytes-reduced lithopones, which consist of mixtures of lithopones with higher zinc sulphide content and ground
mineral barytes. These products should be marked so as to indicate the presence of barytes.
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ISOlR 473 - 1966 (E)
4. SAMPLING
, Sampling Raw Materials for Paints and Varnishes.*
See IS0 Recommendation R
5. TEST METHODS
5.1 Determination of barium sulphate and total zinc content
5.1.1 Reagents
5.1.1.1 Potassium cyanoferrate (II),** standard volumetric solution, approximately 0.05 M
(standardization factor F).
Dissolve 21 .Og of potassium cyanoferrate(II), 300 mg of potassium cyanoferrate(II1) * * *
and 2 g of anhydrous sodium carbonate (to stabilize the solution) in distilled water
and dilute with distilled water to 1000 ml in a graduated flask.
5.1.1.2 Zinc chloride standard solution, approximately 5 g of zinc per litre (concentration c).
Weigh about 5 g of chemically pure zinc to the nearest 0.1 mg, dissolve in 300 ml
of hydrochloric acid 4 M and dilute the solution obtained with distilled water to
1000 ml in a graduated flask.
5.1.1.3 Diphenylamine ethanolic solution, 5 g per 100 ml.
5.1.1.4 Congo paper.
5.1.1.5 Hydrochloric acid 4 M.
5.1.1.6 Sulphuric acid 2 M.
5.1.1.7 Ammonia solution (d = 0.9).
5.1.1.8 Ammonia solution 4 M.
5.1.1.9 Lead acetate paper.
5.1.2 Standardization of the potassium cyanoferrate (ZZ) solution
Take 25.0 ml of the zinc chloride solution by means of a pipette and add ammonia solution
4 M until a piece of Congo paper, touched onto the solution, just turns to a pure red colour.
Then carefully neutralize the solution with hydrochloric acid from a dropping bottle. Add
a few drops in excess until the Congo paper turns to a lasting red-blue or blue-red
colour (pH 1.5 to 3.0).
Make up to 150 ml with distilled water, heat the solution to boiling and add 10 drops of
the diphenylamine solution.
* At present second Draft IS0 Recommendation No. 731.
* * IUPAC name, formerly called potassium ferrocyanide.
* ** IUPAC name, formerly called potassium ferricyanide.
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IÇOIR 473 - 1966 (E)
Immediately titrate the solution with the potassium cyanoferrate (II) solution until the
colour turns to a lasting yellow or yellowish green (Vi millilitres being used).
Then backtitrate the solution with the zinc chloride solution until the colour just turns to
blue again ( V2 millilitres being used). The standardization factor Pexpressed in grammes
of zinc per millilitre of the potassium cyanoferrate (II) solution is
c (25 + vz)
F=
vi
where c = concentration of the standard zinc chloride solution, in grammes of zinc
per millilitre;
Vi = volume of the potassium cyanoferrate (II) solution required for the
titration, in millilitres ;
VZ = volume of the standard zinc chloride solution required for the back-
titration, in millilitres.
5.1.3 Procedure
Weigh to the nearest 0.1 mg about 0.6 g of 30% lithopone (dried at 105 & 2 OC) or
about 0.3 g of 60% lithopone (dried at 105 & 2 OC) (mi grammes) into a beaker
and add 25 ml of hydrochlori
...