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UDC 669.74 Ref. No.: IS0 / R 321 - 1963 (E)
IS0
FO R STA ND AR D I2 AT I O N
I N T ERN AT I O N AL O RG A N I ZAT I O N
IS0 RECOMMENDATION
R 321
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF PHOSPHORUS
1st EDITION
July 1963
L'
COPYFSGHT RESERVED
"he 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 321, Methods of Chemical Analysis of Manganese Ores-
of Phosphorus, was drawn up by the Technical Committee ISO/TC 65,
Determination
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. 254) was circulated to all
the IS0 Member Bodies for enquiry. It was approved by the following Member Bodies:
Austria Hungary Republic of
Bulgaria Ireland South Africa
Burma Italy Romania
Chile Japan Spain
Czechoslovakia Netherlands United Kingdom
France Poland U.S.S.R.
Germany Portugal
One Member Body opposed the approval of the Draft: 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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IS0 / R 321 - 1963 (E)
IS0 Recommendation R 321 July 1963
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF PHOSPHORUS
(Atomic mass P : 30.975; molecular mass P,05 : 141.95)
This IS0 Recommendation contains four parts :
I. Introduction . . . section 1,
II. Gravimetric method of phosphorus determination in the form of blue
salt . sections
2 to 5,
III. Volumetric method . sections 6 to 10,
IV. Colorimetric method . sections 1 to 14.
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 phosphorus, take
three more test samples for the determination of hygroscopic moisture.
Calculate the content of phosphorus in ore which is absolutely dry by multiplying the
numerical results of the determination of phosphorus by the conversion factor K, as found
from the foliowing formula:
100
K= -
100-A
where A = hygroscopic moisture content, per cent.
1.2 The determination of phosphorus 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 phosphorus content.
The arithmetical mean of the three results is accepted as the final result.
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IS0 / R 321 - 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 phosphorus content), shown in the tables under clauses 5.2, 10.2 and
14.2, " Accuracy of method ".
The average result of the simultaneous check analysis of the standard sample of manganese
ore for phosphorus 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 phosphorus
content), shown in the tables under clauses 5.2, 10.2 and 14.2, " Accuracy of method ".
For the analysis, take a standard sample of the type of ore to which the sample beinganalysed
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:
cm centimetre
d relative density
gramme
g
grammes per litre
g/1
ml
millilitre
mm millimetre
nm nanometre
PFA pure for analysis
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IS0 / R 321 - 1963 (E)
II. GRAVIMETRIC METHOD
OF PHOSPHORUS DETERMINATION IN THE FORM OF BLUE SALT
2. PRINCIPLE OF METHOD
After removal of arsenic and separation of silicic acid, the phosphorus is precipitated in the form
of ammonium phospho-molybdate. This complex salt is dissolved in ammonia; the solution is
evaporated in a weighed porcelain dish, heated until the residue of ammonium phospho-molybdate
MOO,) is formed, and then weighed.
(P,06*24
3. REAGENTS REQUIRED
3.1 Ammonium hydroxide, PFA (d 0.91).
3.2 Ammonium hydroxide, PFA, diluted 1 : 1.
3.3 Ammonium nitrate, PFA.
3.4 Ammonium bromide (NH,Br), PFA.
3.5 Hydroxylamine hydrochloride (NH,OH*HCI), neutral, PFA, solution (150 g/l).
3.6 Nitric acid, PFA (d 1.40).
3.7 Hydrochloric acid, PFA (d 1.19).
3.8 Hydrochloric acid, PFA, diluted 1 100.
3.9 HydrojZuoric acid, PFA (40 per cent).
3.10 Ammonium nitro-molybdate solution.
Prepare the two following solutions :
First solution. Dissolve 36 g of molybdic acid, PFA, in 35 ml of ammonia (d 0.91) and 50 ml
of water;
Second solution. Pour carefully 115 ml of ammonia (d 0.91), stirring continually, into
575 ml of nitric acid, diluted 1 : 1, and add 230 ml of water.
Cool the two solutions and mix them, adding slowly the first solution to the second and
shaking vigorously to dissolve the white turbidity. Care should be taken to ensure that there
is no rise in the temperature of the solution. Keep the ammonium nitro-molybdate solution
in an open flask for 48 hours, after which it is ready for use. Filter the solution before using.
3.11 Sodium nitrite (NaNO,), PFA, solution (50 g/l).
3.12 Sodium carbonate, PFA (anhydrous).
3.13 Washing solution. 10 ml of nitric acid (d 1.40) and 10 g of ammonium nitrate are dissolved
in 1 litre of water.
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IS0 / R 321 - 1963 (E)
4. PROCEDURE
4.1 Weigh 1 to 2 g of manganese ore into a 300 ml beaker, and dissolve in 40 mi of acid mixture
made up as follows: 3 parts of hydrochloric acid (d 1.19) and 1 part of nitric acid (d 1.40).
After the sample has been dissolved, evaporate the solution until dry. Moisten the residue
with 5 ml of hydrochloric acid (d 1.19), then add 0.5 to 1 g of ammonium bromide, and
again evaporate the solution until dry, to remove arsenic. Repeat this operation twice, after
which, keep the dry residue at 120 to 130 "C for 40 to 60 min.
4.2 Add 20 ml of hydrochloric acid (d 1.19) to the residue, and heat for 2 to 3 min until the salts
are dissolved. Add 40 to 50 ml of hot water, heat the solution to boiling and filter the insol-
uble residue. Wash the residue on the filter with hydrochloric acid, diluted 1 : 100, 3 to 4
times, and then with hot water, 6 to 8 times. Evaporate the filtrate to 50 to 70 ml.
4.3 Place the filter and residue in a platinum crucible, and ignite.
1.40) and 4 to 6 ml of hydrofluoric
Moisten the residue with water; add 2 ml of nitric acid (d
acid, and evaporate until dry. Repeat twice the procedure of adding nitric acid and evaporat-
ing. Gently ignite the residue, add 1 g of anhydrous sodium carbonate, and fuse the whole
at 900 to 1000 "C.
4.4 Extract the fusion in 50 to 60 ml of hot water, and wash the crucible with water. Boil the
solution for 5 to 10 min, and then filter; wash the filter with water, and add the filtrate to the
original solution.
4.5 Evaporate the combined solutions until crystallization of the salts begins. Add 10 to 15 ml
of nitric acid (d 1.40) to the solution and evaporate to syrupy condition. Repeat the evapora-
tion with 10 to 15 in1 of nitric acid (d 1-40), add 10 ml of nitric acid (d 1.40), and dilute with
40 to 50 ml of water. If the manganese dioxide precipitates in the solution, dissolve it by
adding 2 or 3 drops of sodium nitrite solution (50 g/l) to the boiling solution. Boil the solu-
tion until the nitric oxides are completely dispelled, cool, and neutralize with ammonia
until the hydroxides precipitate. Dissolve the precipitate with a few drops of nitric acid
(d 1.40), adding an excess of 1 to 2 ml of the acid.
4.6 To reduce pentavalent vanadium, add 2 ml of hydroxylamine solution (iSOg/I), and then 10 g
of ammonium nitrate. Heat to a temperature of 40 to 50 OC; precipitate with 80 ml of
ammonium nitro-molybdate solution, stir, and allow to stand for 5 or 6 hours for complete
precipitation of ammonium phospho-molybdate.
4.7 Filter off the precipitate of ammonium phospho-molybdate on a slow filter. When filtering is
complete, wash the sides of the beaker with the washing solution 4 or 5 times, pouring
the solution on the filter. Wash the residue 8 to 10 times with washing solution, and dissolve
it in 10 ml of ammonia, diluted 1 : 1, on the filter.
Collect the solution in the beaker in which the precipitation has been carried out. Wash
the filter 3 or 4 times with hot water. To ensure a complete extraction of the residue, again
wash the filter with 10 ml of ammonium hydroxide, diluted 1 : 1, and then 4 or 5 times with
hot water. Evaporate the solution to a volume of 3 to 5 ml, and add 2 ml of ammonium
hydroxide, diluted 1 : 1. Transfer the solution to a weighed porcelain dish of 6 cm diameter,
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IS0 / R 321 - 1963 (E)
carefully wash the sides of the beaker, and evaporate the solution until dry. Carefully ignite
the dish containing the dry residue at 400 to 450 "C until all the residue becomes blue, cool
it in a desiccator, and weigh.
Noms
1. If the ore sample contains a considerable amount of organic matter, it is ignited for 15 to
20 min, at 600 to 700 OC, before being dissolved. The sample is then placed in a beaker
and dissolved.
2. The method recommended may also be applied to the analysis of ores containing lead.
3. Alternatively, for the determination of phosphorus, the filtrate remaining after the
determination of silicic acid may be used (see IS0 Recommendation R 311, Methods of
chemical analysis of manganese ores. Determination of silicon dioxide).
5. EXPRESSION OF RESULTS
5.1 Method of calculation
The percentage content of phosphorus is calculated from the following formula :
A x 0.01724 x 100
P= per cent
G
where
A = weight of residue, in grammes;
0.017 24 = conversion factor for ammonium phospho-molybdate (P,O, 24 MOO,) to
phosphorus ;
G = mass of sample of ore, in grammes.
5.2 Accuracy of method
The permissible tolerances, per cent (absolute value), are given ,A the table below:
Phosphorns content
Permissible tolerance
from (over) to (in absolute value)
0.050 per cent f 0.0015 per cent
0.050 per cent 0.100 per cent -J= 0.0025 per cent
0.100 per cent 0.300 per cent f 0.0045 per cent
0.300 per cent 0.500 per cent f 0.0075 per cent
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IS0 / R 321 - 1963 (E)
m. VOLUMETRIC METHOD
6. PRINCIPLE OF METHOD
After removal of arsenic and separation of silicic acid, phosphorus is precipitated in the form of
ammonium phospho-molybdate, which is dissolved in a standard solution of sodium hydroxide,
the excess of which is titrated with a standard nitric acid solution.
7. REAGENTS REQUIRED
7.1 Ammonium hydroxide, PFA (d 0.91).
7.2 Ammonium hydroxide, PFA, diluted 1 : 1.
7.3 Ammonium nitrate, PFA.
7.4 Ammonium bromide, PFA.
7.5 Hydroxylamine hydrochloride (",OH.HCl), neutral, PFA, solution (1 50 g/l).
7.6 Nitric acid, PFA (d 1.40).
7.7 Hydrochloric acid, PFA (d 1.19).
7.8 Hydrochloric acid, PFA, diluted 1 : 100.
7.9 Hydrofluoric acid, PFA (40 per cent).
7. io Ammonium nitro-molybdate solution.
Prepare the following two solutions :
First solution. Dissolve 36 g of molybdic acid, PFA, in 35 ml of ammonia (d 0.91) and 50 ml
of water.
Second solution. Pour carefully 11 5 ml of ammonia (d 0.91), stirring cont
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