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IS0
INTERNATIONAL ORGANIZATION FOR STANPARDIZATION
IS0 RECOMMENDATION
R 510
RED LEAD
1st EDITION
October 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 &herefore only
by the national standards organization of that country, being
a member of ISO.
For each individual COuntTy 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 510, Red Lead, was drawn up by Technical Committee
Paints, Varnishes and Related Products and their Raw Materials, the Secretariat
ISO/TC 35,
of which is held by the Nederlands Normalisatie-institut ("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
a Draft IS0
Standardizing Associations (ISA) and led, in 1954, to the adoption of
Recommendation.
This first Draft IS0 Recommendation (No. 32) was circulated to all the IS0 Member
Bodies for enquiry in March 1954. As the results of this consultation were not considered
satisfactory, the Technical Committee successively put forward a second and a third
Draft IS0 Recommendation, which were circulated in August 1961 and in November 1963
respectively.
This third Draft was approved, subject to a few modifications of an editorial nature,
by the following Member Bodies:
Argentina Denmark Portugal
Spain
Australia France
Austria Germany Sweden
Belgium India Turkey
Bulgaria Indonesia U.A.R.
United Kingdom
Canada Italy
U.S.S.R.
Chile Japan
Colombia Morocco Yugoslavia
Czechoslovakia Netherlands
No Member Body opposed the approval of the Draft.
The third Draft IS0 Recommendation was then submitted by correspondence to
IS0 RECOM-
the IS0 Council, which decided, in October 1966, to accept it as an
MENDATION.
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IS0 / R 510 - 1- (E)
IS0 Recommendation R 510 October 1966
RED LEAD
1. SCOPE
This IS0 Recommendation establishes the more important requirements for three qualities of
red lead and the methods of test for these requirements.
2. DEFINITION
Red lead. A red to orange-red pigment which consists of lead orthoplumbate (Pb304) and lead
monoxide (PbO) in which no impurities other than those resulting during the course of normal
manufacture are present.
3. REQUIRED CHARACTERISTICS AND THEIR TOLERANCES *
Red lead should have the following characteristics :
High percentage Clause
Ordinary Dispersed
Property red lead describing
red lead
red lead
(non-setting) est methoc
26 32.5 33.5 5.1
Lead dioxide, min. %
74.5 93.2 96.0 5.4
Lead orthoplumbate, min. %
Sum of lead orthoplumbate and free lead
99 I 99 99 5.4
monoxide, min. %
--
Matter volatile at 105 OC, max. 0.3 0.3 0.3 5.5
%
____
5.6
Matter soluble in water, max. 0.3 0.3 0.3
%
0.75 5.7
1.5 0.75
%
Residue on sieve, max.
To be agreed between purchaser
5.8
Oil absorption value
and vendor
** I 30** 5.9
Sedimentation volume, ** min. ml
After exposure in air for
14 days, the mixture des-
cribed in clause 5.10
Non-setting properties 5.10
should still be in a con-
dition suitable for appli-
cation by brush.
* All percentages are calculated from thc original sample.
** High-percentage red lead and dispersed red lead differ, among other things, by the fact that the sedimentation volume
of the latter is higher than that of the former.
IIi
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IS0 / R 510 - 1966 (E)
4. SAMPLING
See IS0 Recommendation R. . , Sampling Raw Materials for Paints and Varnishes.*
5. TEST METHODS
5.1 Determination of lead dioxide (PbO,) content
5.1.1 Reagents
5.1 . 1 . 1 Sodium thiosulphate solution O. 1 N.
5.1.1.2
Standard iodine solution 0.1 N.
5.1.1.3 Starch solution for indicator. Shake 10 g of soluble starch and 10 mg of mercuric
iodide with about 30 ml of water to obtain a homogeneous suspension. Pour it
into 1 litre of boiling water. Boil the solution for 3 min and after that allow to cool.
5.1.1.4 Acetic acid solution, 30 g/lOO ml.
5.1.1.5 Sodium acetate solution. Dissolve 600 g of crystallized sodium acetate hydrate
(C,H30,Na.3H,0) in distilled water and make up to 1 litre.
5.1.2 Procedure
Weigh to the nearest 1 mg, 0.5 to 1.0 g of red lead and transfer to a 250 ml conical flask'
Add successively the following reagents :
30 ml of the sodium thiosulphate solution (accurately measured),
25 ml of the sodium acetate solution,
20 ml of the acetic acid solution.
Stir gently to dissolve the red lead in the liquid. Rub down coarse particles of the pig-
ment by means of a glass rod flattened at the end (after this, the rod is carefully rinsed).
If the last traces of the pigment are difficult to dissolve, a little potassium iodide may
be added. The addition of not more than 0.5 g of potassium iodide is recommended.
When the lead oxides are completely dissolved (of course with the exception of insoluble
constituents, such as, e.g., metallic lead particles, etc.), titrate the excess of sodium
thiosulphate with the standard iodine solution (0.1 N), using the starch solution as an
indicator.
At the same time perform a blank determination.
The difference between the consumed quantities of iodine solution is proportional to
the amount of lead dioxide (PbO,), i.e. lead orthoplumbate (Pb,O,).
~
* At present Second Draft IS0 Recommendation No. 731.
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lSO/ R 510 - 1966 (E)
5.1.3 Expression of results
The content of lead dioxide (PbOJ of red lead (A), expressed as a percentage by mass, is
given by the following formula:
1.196 (Vz - VI)
A=
where m1
V, = volume in millilitres of 0.1 N iodine solution required by the blank test;
V, = volume in millilitres of 0.1 N iodine solution required by the test sample;
m, = mass in grammes of the test sample.
5.2 Determination of total lead content by the chromate method *
5.2.1 Reagents
5.2.1.1 Nitric acid, 4 N.
5.2.1.2 Acetic acidsolution, 2 g/100 ml.
5.2.1.3 Congo paper.
5.2.1.4 Ammonium acetate solution 2 M, freshly prepared.
5.2.1.5 Hydrogen peroxide solution, 3 g/lOO ml, free from sulphuric acid.
5.2.1.6 Potassium dichromate solution, 5 g/ 100 ml.
5.2.2 Procedure
Weigh to the nearest 1 mg, 0.5 to 1.0 g red lead and transfer to a 500 ml conical flask.
First add 10 ml of the nitric acid and then, drop by drop, hydrogen peroxide solution,
until the red lead is dissolved completely. Evaporate this solution to dryness to expel
the excess of hydrogen peroxide.
Dissolve the residue in as little nitric acid as possibl
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