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IS0
I NT ERN AT I ON AL O RG A N IZAT I O N FOR STANDARD I2 AT1 ON
IS0 RECOMMENDATION
R 552
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF CALCIUM OXIDE CONTENT
AND MAGNESIUM OXIDE CONTENT
1st EDITION
December 1966
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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 aerefore 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 552, Methods of Chemical Analysis of Manganese Ores-
Determination of Calcium Oxide Content and Magnesium Oxide Content, 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 (GOST).
Work on this question by the Technical Committee began in 1957 and led, in 1959, to
the adoption of a Draft IS0 Recommendation.
In November 1962, this Draft IS0 Recommendation (No. 541) was circulated to all
the IS0 Member Bodies for enquiry. It was approved, subject to a few modifications of an
editorial nature, by the following Member Bodies :
Australia Hungary Romania
Austria India Spain
U.A.R.
Burma Iran
Chile Ireland United Kingdom
Czechoslovakia Italy U.S.S.R.
France Japan Yugoslavia
Germany Poland
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 December 1966, to accept it as an IS0 RECOMMENDATION.
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IS0 / R 552 - 1966 (E)
IS0 Recommendation R 552 Decem ber 1966
METHODS OF CHEMICAL ANALYSIS OF MANGANESE ORES
DETERMINATION OF CALCIUM OXIDE CONTENT
AND MAGNESIUM OXIDE CONTENT
(Atomic mass Ca : 40.08 ; molecular mass Ca0 : 56.08)
(Atomic mass Mg : 24.32 ; molecular mass MgO : 40.32)
This SO Recommendation contains four parts :
I. Introduction. . section 1
II. Gravimetric oxalate method of determination of calcium oxide content sections 2 to 5
III. Volumetric permanganate method of determination of calcium oxide
content. . sections 6 to 10
IV. Gravimetric method of determination of magnesium oxide content in
the form of pyrophosphate . sections 11 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 appro-
priate size.
Simultaneously with the collection of samples for the determination of calcium oxide and
magnesium oxide, take three more test samples for the determination of hygroscopic
moisture.
Calculate the content of calcium oxide and that of magnesium oxide in ore which is absolutely
dry by multiplying the numerical results of these determinations by the conversion factor Ky
as found from the following formula:
1 O0
K=
100 -A
where A = hygroscopic moisture content, per cent.
1.2 The determination of calcium oxide and magnesium oxide 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 determinations to be made.
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IS0 / R 552 - 1966 (E)
Simultaneously and under the same conditions, carry out a check analysis of a standard
sample of manganese ore for calcium oxide and magnesium oxide.
The arithmetical mean of the three results is accepted as the final result.
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 calcium oxide content and magnesium oxide 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 calcium and magnesium oxides should not differ from the result shown in the certifi-
cate by more than the f value of the permissible tolerance (for the corresponding interval
of calcium and magnesium oxide 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 being analysed
belongs.
1.3 The test samples and the residues should be weighed to an accuracy of f. 0.0002 g.
1.4 Deionized 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 con-
centrated 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:
CP chemically pure
d relative density
g gramme
g/l grammes per litre
1 litre
ml millilitre
N standard solution of normal concentration
PFA pure for analysis
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IS0 / R 552 - 1966 (E)
II. GRAVIMETRIC OXALATE METHOD OF DETERMINATION
OF CALCIUM OXIDE CONTENT
2. PRINCIPLE OF METHOD
After the separation of silicic acid, manganese hydroxide, ferric hydroxide, aluminium hydroxide,
etc., calcium is precipitated by ammonium oxalate solution and the precipitate ignited to oxide.
Calcium oxide content in manganese ore is found by the weighing of its precipitate.
3. REAGENTS REQUIRED
3.1 Ammonium persulphate ((NH&,S,O,), CP.
3.2 Ammonium chloride, CP.
3.3 Sodium carbonate, anhydrous, CP.
3.4 Hydrochloric acid, CP (d 1.19).
3.5 Hydrochloric acid, CP, diluted (1 : 4).
L
3.6 Hydrochloric acid, CP, diluted (1 : 50).
3.7 Sulphuric acid, CP (d 1.84).
3.8 Hydrofuoric acid, PFA, 40%.
3.9 Ammonia, CP, solution, free from carbonates (d 0.91).
3.10 Hydrogen peroxide, CP, 30 % (perhydrol).
3.11 Ammonium chloride, CP, solution (20 g/l).
3.12 Ammonium oxalate, CP, solution (40 g/l).
3.13 Ammonium oxalate, CP, solution (1 g/l).
3.14 Sodium carbonate, CP, solution (10 g/l).
3.15 Methyl-red, alcohol solution (1 g/l).
4. PROCEDURE
4.1 Introduce 1 g of manganese ore into a 100 ml beaker and dissolve while heating in 10 to 15 ml
of hydrochloric acid (d 1.19). Evaporate the solution until dry, add 10 ml of hydrochloric
acid (d 1.19) to the dry residue and again evaporate until dry, keeping the dry residue for
40 to 60 min at a temperature of 120 to 130 OC.
4.2 Pour 10 to 15 ml of hydrochloric acid (d 1.19) onto the dry residue, moderately heat for 3
to 5 min, then add 30 to 40 ml of hot water, heat to boiling, filter off the insoluble residue
through a filter of average density and collect the filtrate in a 350 to 500 ml beaker. Wash the
residue on the filter three to four times with hot hydrochloric acid, diluted (1 : 50), and then
six to eight times with hot water. Transfer the filter with the residue into a platinum crucible,
dry and ignite at a temperature of 500 to 600 OC. After cooling moisten the residue with
two or three drops of water, add two or three drops of sulphuric acid (d 1.84), 5 to 7 ml of
hydrofluoric acid (40%) and evaporate until dry. Ignite the dry residue at a temperature of
500 to 600 OC, cool, mix with 2 to 4 g of sodium carbonate (anhydrous), cover the crucible
with a lid and fuse at a temperature of 900 to 1000 OC for 20 to 25 min. Place the crucible
with the fusion into a 100 to 150 ml beaker, pour 50 to 60 ml of hot water, heat to a complete
decomposition of the fusion, wash the crucible and the lid with water, take them out of the
beaker and boil the solution for 2 to 3 min. Filter off the solution through a filter containing
a small quantity of paper pulp and wash the residue on the filter with the sodium carbonate
solution (10 g/l).
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IS0 / R 552 - 1996 (E)
4.3 Dissolve the washed residue on the filter in 10 to 15 ml of hot hydrochloric acid, diluted
(I : 4), wash the filter three to four times with hot water and add this solution to the major
fraction.
4.4 Evaporate the combined solutions to a volume of 100 to 150 ml, add 5 g of ammonium
chloride, two or three drops of methyl-red and ammonia (d 0.91) until the colour of the
solution changes into yellow. Add to the solution two or three drops of hydrochloric acid
(d 1.19), 3 to 4 g of ammonium persulphate, 4 to 6 ml of ammonia (d 0.91), heat to boiling
and boil to a complete coagulation of the residue. In order to ensure a full precipitation of
manganese it is necessary that the excess of ammonia be maintained in the solution all the
time. Filter off the residue of hydroxides on a rapid filter, wash five to six times with hot
neutral ammonium chloride solution (20 g/i) and wash it off with water into the beaker in
which the precipitation took place. Dissolve the residue on the filter in 30 to 35 ml of hot
hydrochloric acid, diluted (1 : 4), containing ten drops of hydrogen peroxide.
4.5 The residue having been dissolved, wash the filter three to four times with hydrochloric acid,
diluted (I : 50), then four to five times with hot water and discard the filter. Add to the
solution obtained 5 g of ammonium chloride and repeat the precipitation of hydroxides by
means of ammonia in the presence of ammonium persulphate as described above. Filter off
the residue, wash eight to ten times with hot neutral ammonium chlorate solution (20 g/l)
and discard it. Add the filtrate to the main solution.
4.6 Evaporate the combined filtrates up to 200 ml and neutralize with ammonia (d 0.91) until
the colour of methyl-red indicator changes. If the residue of aluminium and manganese
hydroxides appears, filter it off, wash with neutral ammonium chloride solution (20 g/l) and
evaporate the solution once again up to 200 ml. Pour hydrochloric acid (d 1.19) to the solution
until acid reaction is obtained and then add 2 to 3 ml of hydrochloric acid in excess.
Heat the solution to boiling, then while stirring carefully pour 40 ml of hot ammonium
oxalate solution (40 g/l) and several drops of ammonia (d0.91) until the colour of the indicator
changes, boil for 1 to 2 min, and allow to stand for 12 hours.
4.7 Filter off the residue of calcium oxalate on a dense filter, wash the beaker and the filter with
(I g/l). Keep the filtrate
the residue eight to ten times using cold ammonium oxalate solution
for the determination of magnesium oxide. Dissolve the residue on the filter in 20 ml of
hydrochloric acid, diluted (1 : 4), collecting the solution into the beaker in which the precipi-
tation of calcium took place. Wash the filter six to eight times with hydrochloric acid,
diluted (I : 50).
Dilute the solution with water up to 100 to 150 ml and repeat (under the same conditions)
the precipitation
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