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Ref. No.: ISO/R 805 -1968 (E)
IS0
I N TERN AT1 O N A L O R G A N IZAT I ON FOR STA N DARD IZATl ON
I SO R EC O M M EN DATI O N
R 805
ALUMINIUM OXIDE
PRIMARILY USED FOR THE PRODUCTION OF ALUMINIUM
DETERMINATION OF IRON CONTENT
1,l O-P H EN ANTH R O LI N E P H OTOM ET R I C M ETH O D
1st EDITION
August 1968
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The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
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by the national standards organization ‘of that country, being
of ISO.
a member
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 805, Aluminium oxide primarily used for the production of
aluminium - Determination of iron content - I,I O- phenanthroline 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 1961 and led, in 1964, to the
adoption of a Draft IS0 Recommendation.
In July 1966, this Draft IS0 Recommendation (No. 1027) 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 India Spain
Belgium Ireland Sweden
Brazil Israel Switzerland
Bulgaria Italy Turkey
Canada Japan U.A.R.
Chile
Netherlands United Kingdom
Czechoslovakia
Norway U.S.A.
France Poland
U.S.S.R.
Germany Romania
Yugoslavia
Hungary South Africa,
Korea, Rep. of Rep. of
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 August 1968, to accept it as an IS0 RECOMMENDATION.
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ISO/R 805 -1968 (I
IS0 Recommendation R 805 August 1968
ALUMINIUM OXIDE
PRIMARILY USED FOR THE PRODUCTION OF ALUMINIUM
DETERMINATION OF IRON CONTENT
1,lO-PHENANTH ROLlNE PHOTOMETRIC METHOD
1. SCOPE
This IS0 Recommendation describes a method for the photometric determination of iron content of
aluminium oxide.
2. FIELD OF APPLICATION
The method is applicable to iron contents, expressed as iron (III) oxide (Fe,O,), greater than
0.005 'Io.
3. PRINCIPLE
Preliminary reduction of trivalent iron by means of hydroxylammonium chloride.
Formation of the bivalent iron - 1,lO- phenanthroline complex in a buffered medium (pH value
between 3.5 and 4.2)*.
Photometric measurement at a wavelength of about 5 10 nm.
4. REAGENTS
Distilled water or water of equivalent purity should be used in the test.
4.1 Hydroxylammonium chloride, 1 O g/l solution. Dissolve 1 O g of hydroxylammonium chloride
(NH,OH.HCl) in water and dilute to 1000 ml.
4.2 1,IO-phenanthroline hydrochloride, 2.5 g/l solution. Dissolve 2.5 g of 1 ,l@phenanîhroiine
hydrochloride monohydrate (Cl 2H,N2 .HCl.H,O) in water and dilute to 1000 mi. (1,lO-
phenanthroline hydrochloride monohydrate may be replaced by 1 ,IO-phenanthrolme mono-
hydrate.
* Aluminium, elements usually present in aluminium oxide (impurities) and flux do not cause interference.
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4.3 Buffer solution. Dissolve 272 g of sodium acetate trihydrate (CH3COONa.3HzO) in approxi-
mately 500 ml of water. Add 240 ml of glacial acetic acid (CH,COOH) approximately 17.4 N
and dilute to 1000 ml.
4.4 Sodium acetate, 500 g/i solution. Dissolve 50 g of sodium acetate trihydrate (CH3COONa.3H,0)
in water and dilute to 100 ml.
Acetic acid solution. Dilute 500 nil of glacial acetic acid (CH,COOH) approximately 17.4 N
4.5
with water to 1 O00 ml.
4.6 Iron, standard solution equivalent to 0.20gll of iron (III) oxide (Fe20,). This solution should
be prepared by one of the two following methods :
4.6.1 Weigh to the nearest 1 mg, 0.982 g of ammonium-iron (II) sulphate hexahydrate
[(NH4),Fe(S04),.6H,0 ] place in a beaker of suitable capacity and dissolve in water.
Add 20 ml of sulphuric acid d = 1.83, transfer quantitatively to a 1000 ml one-mark
volumetric flask and dilute to the mark.
4.6.2 Weigh to the nearest 1 mg, 0.200 g of iron (III) oxide (Fe,03) previously ignited at 600 "C
and allowed to cool in a desiccator. Place it in an approximately 100 mi beaker, add 10 ml
of hydrochloric acid solution d = 1.18 (approximately 37 m/m solution) and heat gently
until it is completely dissolved. Allow to cool, quantitatively transfer to a 1000 ml one-mark
volumetric flask and dilute to the mark.
1 mi of this standard solution is equivalent to 0.2 mg of Fe,03.
4.1 Iron, standard solution containing O. OlOgll of iron (III) oxide (Fe,Os). Transfer 50.0 ml of the
standard solution (4.6) to a 1000 ml one-mark volumetric flask and dilute to the mark.
1 ml of this standard solution is equivalent to 10 pg of Fe,O,.
The solution should be prepared just before use.
4.8 pH paper, covering the range 3.5 to 4.2 at intervals of 0.2 units.
5. APPARATUS
Ordinary laboratory apparatus and
pH meter, with a glass electrode.
5.1
5.2
...