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UDC 669.74
IS0
I NT ERN AT1 ON AL FOR STA ND AR D IZ AT1 O N
O RG A N IZAT I O N
I S O R E CO M M E N DATI O N
i
R 320
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF SULPHUR
1 çt EDITION
July 1963
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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 320, Methods of Chemical Analysis of Manganese Ores-
Determination of Sulphur, was drawn up by Technical Committee TSO/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. 253) was circulated to all the
IS0 Member Bodies for enquiry. It was approved by the following Member Bodies:
Austria Hungary Portugal
Bulgaria India Republic of
Burma Ireland South Africa
Chile Italy
Romania
Czechoslovakia Japan Spain
France Netherlands United Kingdom
Poland
Germany U.S.S.R.
One Member Body opposed the approval of the Draft: Finland.
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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BO/ R 320 - 1963 (E)
IS0 Recommendation R 320 July 1963
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF SULPHUR
(Atomic mass S : 32.066)
This IS0 Recommendation contains four parts:
I. Introduction. . section 1,
II. Gravimetric method (first variant), for sulphur content exceeding 0.01
per cent . sections 2 to 5,
III. Gravimetric method (second variant), for sulphur content exceeding
0.01 per cent . sections 6 to 9,
IV. Combustion method . sections 10 to 15.
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 sulphur, take three
more test samples for the determination of hygroscopic moisture.
Calculate the content of sulphur in ore, which is absolutely dry, by multiplying the numerical
results of the determination of sulphur by the conversion factor K, as found from the
following formula :
100
I(=---
100-A
where A = hygroscopic moisture content, per cent.
1.2 The determination of sulphur 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 sulphur content.
The arithmetical mean of the three results is accepted as the final result.
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iSO/ R 320 - 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 corre-
sponding interval of sulphur content), shown in the tables under clauses 5.2, 9.2 and 15.2,
" Accuracy of method ".
The average result of the simultaneous check analysis of the standard sample of manganese
ore for sulphur 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 sulphur content),
shown in the tables under clauses 5.2, 9.2 and 15.2, " 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 i- 0.0002 g.
1.4 Distilled water should be used during the procedure and for the preparation of solutions.
1 .S 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 Tndications 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 arc used:
cm centimetre
d relative density
g gramme
g/1 grammes per litre
ml millilitre
mm millimetre
PFA pure for analysis
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I
iSO/ R 326 - 1983 (E)
II. GRAVIMETRIC METHOD (First Variant)
FOR SULPHUR CONTENT EXCEEDING 0.01 PER CENT
2. PRINCIPLE OF METHOD
When the ore is fused with sodium carbonate and an oxidizing agent at a temperature of 800 to
900 OC, all sulphur contained in the ore (generally in the form of pyrites and barytes) decomposes
into sulphates of sodium. By means of extraction of the fusion with water and filtration, the
sulphate ions are separated from other inherent elements, among which are those that hinder
the determination. The sulphate ions contained in the water extraction are precipitated with
barium chloride, and sulphur is determined in the form of barium sulphate.
3. REAGENTS REQUIRED
3.1 Barium chloride, PFA, solution (100 g/l).
3.2 Magnesium oxide, PFA.
3.3 Methyl red indicator, alcoholic solution, PFA (1 g/l).
3.4 Sodium carbonate, anhydrous, PFA.
i
3.5 Sodium carbonate, solution, PFA (10 g/l).
3.6 Sodium peroxide, PFA.
3.7 Hydrochloric acid, PFA, diluted 1 : 1.
3.8 Washing solrrtion. 10 mi barium chloride solution (100 g/l) and 10 ml hydrochloric acid,
diluted 1 : 1, are diluted with water up to 1 litre.
3.9 Silver nilrate, PFA, solution (1 di).
3.10 Fusion mixture : 30 g of powdered anhydrous sodium carbonate, PFA, are mixed with 25 g
of magnesium oxide, PFA, and 2 g of potassium chlorate (KCIO,), PFA. First, potassium
chlorate is finely ground with a small quantity of sodium carbonate in a porcelain mortar.
Then the remaining quantity of sodium carbonate and magnesium oxide are added and
well mixed together.
3.11 Ethyl alcohol, PFA.
4. PROCEDURE
Determination of sulphur may be carried out in accordance with either
procedure A . see clause 4.1, or
procedure B . see clause 4.2.
4.1 Procedure A
4.1.1 Carefully mix 3 to 5 g of manganese ore and 4 to 7 g of fusion mixture in a platinum
crucible.
Place the crucible in a muffle furnace and heat at 800 to 900 "C for 20 to 30 min. After
cooling, place the crucible in a 300 mi beaker and extract in 75 to 100 ml of hot water.
Heat until the extraction is complete, after which take the crucible out and rinse with
water.
4.1.2 If the solution is tinted to a green colour by a manganate, the latter is reduced by adding
a few drops of ethyl alcohol and heated until complete decolorization is achieved.
4.1.3 Filter the hot solution through an ashless filter into a 500 ml beaker, leaving the greater
part of the residue in the beaker, where the extraction has been effected.
4.1.4 Pour 50 ml of hot solution of sodium carbonate (10 g/l) into the beaker with the residue,
boil for 5 to 10 min, and filter the solution through the same filter. Repeat this operation
2 to 3 times. Wash off the residue from the beaker onto the filter, and wash 4 times
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IS0 / R 320 - 1963 (E)
with a hot solution of sodium carbonate. Carefully neutralize the filtrate, the volume of
which should be about 250 to 300 ml, with hydrochloric acid, diluted 1 : 1, in the pre-
sence of methyl red, subsequently adding to the solution an excess of 1 to 1.5 ml of the
same acid.
4.1.5 Heat the solution to boiling point and then add, drop by drop, 10 to 15 ml of a hot
solution of barium chloride, stirring all the time. Keep the solution gently boiling until
the volume is reduced to 150 to 200 ml. Then allow the precipitate of barium sulphate to
settle for 12 hours.
4.1.6 Filter and collect the precipitate on to a fine filter, containing a small quantity of paper
pulp, and use a jet of cold washing solution for washing off the residue from the beaker.
Wash the precipitate on the filter 3 or 4 times with the washing solution, and then with
warm water until the chlorine ions are completely absent from the washings (test reaction
with silver nitrate).
4.1.7 Place the filter with the precipitate in a weighed platinum or porcelain crucible and
dry. Carefully ignite and heat at 600 to 700 "C for 30 min. Cool the crucible with the
residue in a desiccator and then weigh.
4.2 Procedure B
4.2.1 Carefully mix a test sample of 3 to 5 g of manganese ore, 3 to 5 g of sodium carbonate
and 3 to 5 g of sodium peroxide in a nickel crucible.
Place the crucible in a mufle furnace and ignite for 20 to 30 min, at 550 to 600 OC.
After cooling, place the crucible in a 500 ml beaker, containing 100 to 150 ml of water,
and heat the fused mass until completely disintegrated. Remove the crucible and carefully
rinse with hot water over the beaker.
4.2.2 The additional operations (from the reaction of reduction of manganate with alcohol)
should be carried out in accordance with Procedure A.
5. EXPRESSION OF RESULTS
5.1 Method of calculation
The percentage content of sulphur is calculated from the following formula:
A x 0.1374 x 100
S= per cent
G
A = mass of barium sulphate, in grammes;
where
0.1374 = conversion factor for barium sulphate to sulphur;
G = mass of sample of ore, in grammes.
5.2 Accuracy of method
The permissible tolerances, per cent (absolute value), are given in the table below:
Sulphur content
Permissible tolerance
(in absolute value)
from to
0.010 per cent 0.030 per cent f 0.001 per cent
(over) 0.030 per cent 0.050 per cent f 0.002 per cent
,, 0.050 per cent 0.100 per cent f 0.003 per cent
,, 0.100 per cent 0.200 per cent f 0.006 per cent
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,IS0 / R 320 - 1963 (E)
ïïI. GRAVIMETRIC METHOD (Second Variant)
FOR SULPHUR CONTENT EXCEEDI
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