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IS0
I NTERN AT I O NA L O RG A N I ZAT I ON FOR STA N D A R D I Z AT I O N
IS0 RECOMMEN DATI ON
R 323
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF LEAD
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 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 323, Methods of Chemical Analysis of Manganese Ores-
Determination of Lead, 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,
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to the adoption of a Draft IS0 Recommendation.
In October 1958, this Draft IS0 Recommendation (No. 256) was circulated to all the
IS0 Member Bodies for enquiry. It was approved by the following Member Bodies:
Austria Hungary Portugal
Bulgaria Ireland Republic of South Africa
Romania
Burma Italy
Chile Japan United Kingdom
Czechoslovakia Netherlands Spain
Germany Poland U.S.S.R.
Two Member Bodies opposed the approval of the Draft:
France, India.
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 323 - 1963 (E)
I SO Reco m men dation R 323 July 1963
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF LEAD
(Atomic mass Pb : 207.21; molecular mass PbO : 223.21)
This IS0 Recommendation contains three parts :
I. Introduction . section 1,
II. Gravimetric method of lead determination in the form of lead molyb-
sections 2 to 5,
date, for lead content over 0.1 per cent .
III. Volumetric cerium method (ceric sulphate standardization), for lead
sections 6 to 10.
content below 0.1 per cent .
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.
of samples for the determination of lead, take three more
Simultaneously with the collection
test samples for the determination of hygroscopic moisture.
Calculate the content of lead in ore which is absolutely dry by multiplying the numerical
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results of the determination of lead by the conversion factor Ky as found from the following
formula :
100
K=
100 - A
where A = hygroscopic moisture content, per cent.
1.2 The determination of lead 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 lead content.
The arithmetical mean of the three results is accepted as the final result.
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ISO/ R 323 - 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 cor-
responding interval of lead content), shown in the tables under clauses 5.2 and 10.2, “Accur-
acy of method”.
The average result of the simultaneous check analysis of the standard sample of manganese
ore for lead content should not differ from the result shown in the certificate by more than
f value of the permissible tolerance (for the corresponding interval of lead content),
the
shown in the tables under clauses 5.2 and 10.2, “ 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
gP grammes per litre
mg milligramme
ml millilitre
mm millimetre
PFA pure for analysis
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iSO/ R 323 - 1963 (E)
I
II. GRAvlMETRIC METHOD OF LEAD DETERMINATION
IN THE FORM OF LEAD MOLYBDATE
FOR LEAD CONTENT OVER 0.1 PER CENT
2. PRINCIF'LE OF METHOD
The method consists in the separation of lead from the accompanying elements in the form of
lead sulphide, the solution of the latter in ammonium acetate, and the subsequent precipitation of
the lead with ammonium molybdate.
3. REAGENTS REQUIRED
3.1 Ammonium nitrate, PFA, solution (20 di).
3.2 Ammonium acetate, PFA, solution (300 g/I).
3.3 Ammonium chloride, PFA, solution (150 g/l).
3.4 Ammonium molybdate, PFA, solution (50 g/l).
3.5 Ammonium hydroxide, PFA (d 0.91).
3.6 Ammonium sulphate, PFA, solution (100 di).
3.7 Ferrous sulphide (FeS), PFA (to obtain hydrogen sulphide).
3.8 Nitric acid, PFA (d 1.40).
3.9 Sulphuric acid, PFA (d 1.84).
3.10 Sulphuric acid, PFA, diluted 1 : 50.
3.11 Hydrochloric acid, PFA (d 1.19).
3.12 Hydrochloric acid, PFA, diluted 1 : 1.
3.13 Citric acid, PFA, solution (200 di).
3.14 Copper sulphate, PFA, solution (10 g/l).
3.15 Sodium chloride, PFA, solution (150 g/i).
3.16 Sodium sulphide (Na&, PFA, solution (50 di).
3.17 Hydrogen peroxide, PFA, 30 per cent (perhydrol).
3.18 Ethyl alcohol, PFA.
4. PROCEDURE
4.1 Weigh 5 g of manganese ore into a 300 ml beaker, and digest by heating in 30 ml of hydro-
chloric acid (d 1.19). Add, drop by drop, 3 to 5 ml of nitric acid (d 1.40), boil for 5 min, and
evaporate until dry. Add 15 ml of hydrochloric acid (d 1.19) to the dry residue, and again
evaporate until dry. Add to the residue 20 mi of hydrochloric acid (d 1.19), heat for 2 to
3 min, add 40 to 50 ml of hot water, 10 mi of ammonium acetate solution (300 g/l) and 5 ml
of citric acid solution (200 di), heat to boiling, and boil for 5 min.
4.2 Filter the insoluble residue, and wash 6 to 8 times with hot water.* Add ammonium hydroxide
(d 0.91) to the filtrate until precipitation of the hydroxides occurs. Carefully dissolve the
The residue may be used for determination of silicon dioxide content.
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lSO/ R 323 - 1963 (E)
precipitate in hydrochloric acid, diluted 1 : 1, using not more than 3 to 4 ml excess, add 1 ml
of copper sulphate solution (10 g/l), heat to boiling, pass hydrogen sulphide for a period of
20 min, dilute with water to 350 to 400 ml, and again pass hydrogen sulphide for a period
of 20 min.
Let stand for 10 to 12 hours, then filter on a close filter containing a small quantity of paper
pulp; wash 5 or 6 times with water saturated with hydrogen sulphide, until removal of iron
ions is complete. Discard the filtrate.
4.3 To remove arsenic and antimony, wash the precipitate with sodium sulphide solution (50 di).
Place the filter with residue in the beaker in which the precipitation took place, dissolve
it in 15 to 20 ml of acid mixture (2 parts of sulphuric acid (d 1.84), and 1 part of nitric acid
(d 1.40)), loosen the filter with a glass rod, and evaporate until fumes of sulphur trioxide
appear. The contents of the beaker should be colourless. Cool the beaker, add 200 ml of
cold water and 10 to 15 ml of ammonium sulphate solution (100 g/l), heat to boiling, cool,
add 40 to 50 ml of ethyl alcohol, and stir; settle the precipitate for 10 to 12 hours, filter off on
a close filter containing a small quantity of paper pulp; wash with sulphuric acid, diluted 1 : 50,
and discard the filtrate.
Place the filter with the residue in the beaker in which the precipitation of lead sulphate
took place, add 25 to 30 ml of ammonium acetate solution (300 g/l), loosen the filter with a
glass rod, heat to boiling, and boil for 10 to 15 min.
Filter the hot solution through a close filter, wash the sides of the beaker 2 or 3 times and the
residue on the filter 4 or 5 times with hot water, and discard the filter and residue. Add to
the filtrate 25 ml of sodium chloride solution (150 g/l), heat to boiling point, add slowly, and
while stirring, 15 to 20ml of ammonium molybdate solution (50 g/l), and boil for 15 to 20 min.
Allow the residue to settle on a hot plate for 2 hours, then filter it off on a close filter, and
wash 8 to 10 times with a hot solution of ammonium nitrate (20 di).
Place the filter with the residue in a weighed porcelain crucible, ignite carefully at a tem-
perature of 450 to 550 OC, cool, and weigh.
5. EXPRESSION OF RESULTS
5.1 Method of calculation
The percentage content of lead is calculated from the following formula:
A x 0.5644 x 100
Pb = - per cent
G
where A = mass of lead molybdate residue, in grammes;
0.5644 = conversion factor for lead molybdate to lead oxide;
G = mass of sample of ore, in grammes.
5.2 Accuracy of method
The permissible tolerances, per cent (absolute va
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