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UDC 669.74
IS0
I NT ERN AT1 O NA L O RG A N IZATI O N FOR STA N DAR D IZ AT1 O N
IS0 RECOMMENDATION
R 313
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF TOTAL IRON CONTENT
1 çt EDITION
July 1963
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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 oniy 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 313, Methods of Chemical Analysis of Manganese Ores-
Determination of Total Iron Content, was drawn up by Technical Committee ISO/TC 65,
Manganese Ores, the Secretariat of which is held by the Komitet Standartov, Mer i Izme-
ritel’nyh Priborov pri Sovete Ministrov SSSR.
Work on this question by the Technical Committee began in 1954 and led, in 1957,
to the adoption of a Draft IS0 Recommendation.
In October 1958, this Draft IS0 Recommendation (No. 246) was circulated to all
the IS0 Member Bodies for enquiry. It was approved by the following Member Bodies:
Austria Germany Poland
Bulgaria Hungary Portugal
Burma India Republic of South Africa
Chile Ireland Romania
Czechoslovakia Italy Spain
Finland Japan United Kingdom
France Netherlands U.S.S.R.
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 July 1963, to accept it as an IS0 RECOMMENDATION.
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iSO/ R 313 - 1963 (E)
IS0 Recommendation R 313 July 1963
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF TOTAL IRON CONTENT
(Atomic mass Fe : 55.85 ; molecular mass Fe0 : 71.85 ; molecular mass Fe,O, : 159.70)
This IS0 Recommendation contains three parts :
I. Introduction . section 1,
II. Dichromate method, first variant . sections 2 to 5,
III. Dichromate method, second variant, for ores containing copper, lead and
arsenic . sections 6 to 9.
I. INTRODUCTION
1. GENERAL INSTRUCTIONS
1.1 In the following analysis, use a sample for chemical analysis of air-dried manganese ore,
which has been crushed to a size not exceeding 0.10 mm and checked on a sieve of appro-
priate size.
Simultaneously with the collection of samples for the determination of total iron, take
three more test samples for the determination of hygroscopic moisture.
Calculate the content of total iron in ore which is absolutely dry by multiplying the
numerical results of the determination of iron by the conversion factor K, as found from the
following formula:
100
K= ~
100- A
A = hygroscopic moisture content, per cent.
where
1.2 The determination of total iron in manganese ore is carried out by simultaneously analysing
three samples of ore, with two blank determinations to enable a corresponding correction in
the result of the determination to be made.
Simultaneously and under the same conditions, carry out a check analysis of a standard
sample of manganese ore, for total iron content.
The arithmetical mean of the three results is accepted as the final result.
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iSO/ R 313 - 1963 (E)
The following conditions should be observed:
The maximum difference between the highest and the lowest results should not exceed
double the absolute value of the permissible tolerance on the result of the analysis (for the
corresponding interval of total iron content), shown in the tables under clauses 5.2 and 9.2,
“ Accuracy of method ”.
The average result of the simultaneous check analysis of the standard sample of manganese
ore for total iron content should not differ from the result shown in the certificate by more
than the f value of the permissible tolerance (for the corresponding interval of total iron
content), shown in the tables under clauses 5.2 and 9.2, “ Accuracy of method ”.
For the analysis, take a standard sample of the type of ore to which the sample being analysed
belongs.
1.3 The test samples and the residues should be weighed to an accuracy of f 0.0002 g.
1.4 Distilled water should be used during the procedure and for the preparation of solutions.
1.5 Meanings of the following expressions :
hot water (or solution) implies a temperature of the liquid of 60 to 70 OC;
warm water (or solution) implies a temperature of the liquid of 40 to 50 OC;
diluted 1 : 1, 1 : 2, 1 : 5, etc. means that
the first figure gives the number of parts by volume
of concentrated acid or some other solution, and
the second figure gives the number of parts by volume
of water.
1.6 Indications as to the concentration of solutions show the quantity of solute (in grammes) in
the corresponding volume of the solvent.
1.7 The following symbols and abbreviations are used:
d relative density
g gramme
g/l grammes per litre
J
ml millilitre
mm millimetre
PFA pure for analysis
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lSO/ R 313 - 1963 (E)
II. DICHROMATE METHOD - FIRST VARIANT
2. PRINCIPLE OF METHOD
The sample of ore is dissolved in concentrated hydrochloric acid (d 1.19). Trivalent iron is
reduced with stannous chloride. The surplus stannous chloride is oxidized with mercuric chloride.
The reduced iron is titrated with a solution of potassium dichromate in the presence of sodium
diphenylamine sulphonate indicator.
.
3. REAGENTS REQUIRED
Hydrochloric acid, PFA (d 1.19).
3.1
L
3.2 Stannous chloride solution, PFA (100 g/l). 10 g of stannous chloride are dissolved while
heating in 50 ml of hydrochloric acid (d 1.19) to which are added 50 ml of water.
3.3 Mercuric chloride solution, PFA, (50 g/l).
3.4 Sodium diphenylamine sulphonate indicator solution (0.8 g/l).
3.5 Acid mixture : 250 ml of sulphuric acid (d 1.84) are carefully poured into 750 ml of water;
50 ml of phosphoric acid (d 1.7).
when the mixture is cool, add to it
3.6 Standard solution of potassium dichromate : 1.7558 g of potassium dichromate, PFA, re-
crystallized and dried at a temperature of 180 to 200 OC, are dissolved in a small quantity
of distilled water and placed in a measuring flask of 1 litre capacity; add more water until
the level of the solution reaches the mark. 1 ml of this solution is required for 0.002 g of iron.
4. PROCEDURE
4.1 Weigh 0.5 to 1 g of manganese ore, depending on iron content, into a 100 ml beaker. Add
(d 1.19) and heat until the attack is complete. Add the
10 to 15 ml of hydrochloric acid
stannous chloride solution (100 g/l) drop by drop until the solution is decolorized, adding
subsequently an excess of not more than 1 to 2 drops. Transfer the reduced solution of iron to
a 500 ml flask, was
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