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IS0
I NT ERN AT I ON AL O RG A N I ZAT I O N FOR STAND AR D I Z AT I O N
IS0 RECOMMENDATION
R 317
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF ARSENIC
1 st 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 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 31 7, Methods of Chemical Analysis of Manganese Ores-
Determination of Arsenic, was drawn up by Technical Committee ISO/TC 65, Manganese
Ores, the Secretariat of which is held by the Komitet Standartov, Mer i Izmeritel’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. 250) was circulated to all the
IS0 Member Bodies for enquiry. It was approved by the following Member Bodies:
Austria Hungary Portugal
Republic of
Bulgaria India
Ireland South Africa
Burma
Chile Italy Romania
Czechoslovakia Japan Spain
France Netherlands United Kingdom
Germany Poland 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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lSO/ R 317 - 1963 (E)
IS0 Recommendation R 317 July 1963
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF ARSENIC
(Atomic mass As: 74.91)
This IS0 Recomrnenda 1 n contains two parts:
I. Introduction . section I,
L
II. Colorimetric method of arsenic determination in the form of a blue arseno-
molybdate complex . 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 appro-
priate size.
Simultaneously with the collection of samples for the determination of arsenic, take three
more test samples for the determination of hygroscopic moisture.
'L
Calculate the content of arsenic in ore which is absolutely dry by multiplying the numerical
results of the determination of arsenic 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 arsenic in manganese ore is carried out by simultaneously analysing
three samples of ore, with two blank determinations to enable a corresponding correction in
of the determination to be made.
the result
Simultaneously and under the same conditions, carry out a check analysis of a standard
sample of manganese ore, for arsenic content.
The arithmetical mean of the three results is accepted as the ha1 result.
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lSO/ R 317 - 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 arsenic content), shown in the table under clause 5.2, “ Accuracy
of method ”.
The average result of the simultaneous check analysis of the standard sample of manganese
ore for arsenic content should not differ from the result shown in the certificate by more than
the & value of the permissible tolerance (for the corresponding interval of arsenic 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 test samples and the residues should be weighed to an accuracy of & 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.
The following symbols and abbreviations are used:
d relative density
g gramme
g/1 grammes per litre
ml millilitre
mg milligramme
mm millimetre
nm nanometre
PFA pure for analysis
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lSO/ R 317 - 1983 (E)
II. COLORIMETRIC METHOD OF ARSENIC DETERMINATION
IN THE FORM OF A BLUE ARSENO-MOLYBDATE COMPLEX
2. PRINCIPLE OF METHOD
The method is based on the separation of arsenic from the accompanying elements by distilling it
off from a hydrochloric solution in the presence of the reducers, hydrazine sulphate and potassium
bromide. The reduced arsenic is oxidized with nitric acid until it becomes pentavalent; the
pentavalent arsenic and molybdic acid form a yellow arseno-molybdate compl
...