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IS0
I NT ERN AT I ON A L ORGAN IZATl O N FOR STAND AR D IZATl ON
IS0 RECOMMENDATION
R 900
ALUMINIUM OXIDE
PRIMARILY USED FOR THE PRODUCTION OF ALUMINIUM
DETERMINATION OF TITANIUM CONTENT
Tiron photometric method
1st EDITION
Decem ber 1968
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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 900, Aluminium oxide primarily used for the production of
of aluminium - Determination of titanium content - Tiron photometric method, was drawn up by
Technical Committee ISO/TC 47, Chemistry, the Secretariat of which is held by the Ente Nazionale
Italian0 di Unificazione (UNI).
Work on this question by the Technical Committee began in 1962 and led, in 1966, to the
adoption of a Draft IS0 Recommendation.
In May 1967, this Draft IS0 Recommendation (No. 1170) 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 :
Austria Israel Spain
Belgium Italy South Africa, Rep. of
Bulgaria Japan Sweden
Canada Korea, Dem. P. Rep. of Switzerland
Czechoslovakia Korea, Rep. of Thailand
France Net herlands Turkey
U.A.R.
Germany New Zealand
United Kingdom
Hungary Norway
U.S.A.
India Poland
U.S.S.R.
Iran Portugal
Romania Yugoslavia
Ireland
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council,
which decided, in December 1968, to accept it as an IS0 RECOMMENDATION.
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ISO/R 900-1968 (f
IS0 Recommendation R 900 Decem ber 1968
ALUMINIUM OXIDE
PRIMARILY USED FOR THE PRODUCTION OF ALUMINIUM
DETERMINATION OF TITANIUM CONTENT
Tiron photometric method
1. SCOPE
This IS0 Recommendation describes a tiron photometric method for the determination of titanium in
aluminium oxide primarily used for the production of aluminium.
2. FIELD OF APPLICATION
The method is applicable to the titanium contents found in the industrial material, providing that
the Fe,O, content is less than 0.045 and the V,O, content less than 0.008
2.1 Special cases
2.1.1 When the Fe,O, content is greater than 0.045 (see clause 8.1).
(see clause 8.2).
2.1.2 When the V,O, content is greater than 0.008
3. PRINCIPLE
Formation of the titanium-tiron complex at pH 3.8 f 0.1.
Photometric measurement of the coloured complex at a wavelength of about 380 nm.
4. REAGENTS
Distilled water or water of equivalent purity should be used in the test.
4.1 Sodium carbonate, anhydrous.
4.2 Boric acid (H, BO,).
Nitric acid, approximately 8 N solution.
4.3
Dilute 540 ml of nitric acid solution d = 1.4 (approximately 68 m/m solution) with water
to 1000 ml.
Tiron, 80 g/l solution.
4.4
Dissolve 80 g of tiron (disodium -1.2 dhydroxy -3.5 disulphonate) in water and dilute to
1000 ml. The quality of the solution of this reagent should be confirmed by a preliminary test.
The solution should be prepared at weekly intervals.
4.5 Sodium acetate, approximately 4 M solution.
Dissolve 54.4 g of sodium acetate trihydrate in water and dilute to 100 ml.
4.6 Buffer solution (pH 3.8).
Dissolve 98 g of sodium acetate trihydrate in about 400 ml of water, add 280 ml of glacial
acetic acid d = 1 .O5 (approximately 17.4 N solution) and dilute to 1000 ml.
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ISO/R 900-1968 (I
6. PROCEDURE
6.1 Preparation of the sample solution (principal solution P).
Follow the instructions given in clauses 5.1, 5.2 and 5.3 of IS0 Recommendation R 804,
Aluminium oxide primarily used for the production of aluminium - Preparation of sample
solution for analysis, making the final volume of the principal solution 250 ml.
This sample solution should be prepared just before use.
6.2 Test portion
Into both a beaker of convenient size (100 ml, for example) and a 100 rnl one-mark volu-
metric flask transfer a 25.0 ml aliquot of the principal solution (6.1), each containing 0.500 g
of dried* sample.
6.3
Preparation of the calibration curve
6.3.1 Preliminary test to adjust pH. Transfer to a beaker of convenient size (100 ml, for example)
8 ml of the standard titanium solution (4.10) containing 32 pg of TiO, and 2 ml of ascorbic
acid solution (4.7) and dilute to approximately 40 ml. Add 10 ml of the tiron solution (4.4)
(see clause 9.1) and then add slowly, by means of a graduated pipette or a
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