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UDC 669.74
IS0
I N T ERN AT I O N AL O R G A N 1 Z AT 1 ON FOR STAND A RD I2 AT I ON
IS0 R ECOM MEN DATI O N
R 311
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF SILICON DIOXIDE
1st EDITION
July 1963
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 3 1 1, Methods of Chemical Analysis of Manganese Ores-
Determination of Silicon Dioxide, 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,
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to the adoption of a Draft IS0 Recommendation.
In October 1958, this Draft IS0 Recommendation (No. 244) was circulated to all the
IS0 Member Bodies for enquiry. It was approved by the following Member Bodies:
Austria Hungary Republic of
Bulgaria Ir e 1 and South Africa
Burma Italy Romania
Chile Japan Spain
Czechoslovakia Netherlands United Kingdom
Finland Poland U.S.S.R.
Germany Portugal
Two Member Bodies opposed the approval of the Draft:
France, India.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
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Council, which decided, in July 1963, to accept it as an IS0 RECOMMENDATION.
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iSO/ R 311 1 - 1963 (E)
IS0 Recommendation R 311 July 1963
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF SILICON DIOXIDE
(Atomic mass Si : 28.09, molecular mass SiO,: 60.09)
This IS0 Recommendation contains two parts:
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I. lntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,
section
II. Gravimetric hydrochloric acid method of determination of silicon dioxide sections 2 to 5,
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 appropriate
size.
Simultaneously with the collection of samples for the determination of silicon dioxide, take
three more test samples for the determination of hygroscopic moisture.
Calculate the content of silicon dioxide in ore which is absolutely dry by multiplying the
numerical results of the determination of silicon dioxide by the conversion factor K, as found
from the following formula:
100
K- -
100- A
where A = hygroscopic moisture content, per cent.
1.2 The determination of silicon dioxide 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 silicon dioxide content.
The arithmetical mean of the three results is accepted as the final result.
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[SO/ R 311 - 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 corres-
5.2, " Accuracy
ponding interval of silicon dioxide content), shown in the table under clause
".
of method
The average result of the simultaneous check analysis of the standard sample of manganese
ore for silicon dioxide 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 silicon
dioxide content), shown in the table under clause 5.2, " 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 samples and the silica residues should be weighed to an accuracy of it 0.0002 g.
1.4 Distilled water should be used during the procedure and for the preparation of solutions.
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1.5 Meanings of the following expressions :
hot water (or solution) implies a temperature of the liquid of 60 to 70 "C;
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 con-
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