ISO 6609:1985
(Main)Aluminium ores — Determination of iron content — Titrimetric method
Aluminium ores — Determination of iron content — Titrimetric method
The method ist applicable to ores containing between 2 and 50 % (m/m) iron oxide. The method has been chosen to avoid interference from platinum which may occur with the use of platinum crucibles. Specifies principle, reagents, apparatus, sampling and preparation of samples, procedure, expression of results and test report.
Minerais alumineux — Dosage du fer — Méthode titrimétrique
Aluminijeve rude - Določevanje celotnega železa - Titrimetrijska metoda
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International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION*MElKt(AYHAPO~HAR OPrAHM3ALU4R I-IO CTAH~APTM3A~MM.ORGANISATlON INTERNATIONALE DE NORMALISATION
Aluminium ores - Determination of iron content -
Titrimetric method
Minerals alumineux - Dosage du fer - Mkthode titrim&rique
First edition - 1985-07-01
UDC 553.492 : 543.24 : 546.72 Ref. No. IS0 6609-1985 (E)
Descriptors : minerals and ores, aiuminium ores, chemical analysis, determination of content, iron, volumetric analysis.
Price based on 4 pages
---------------------- Page: 1 ----------------------
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 technical committees. Each member
body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the IS0 Council. They are approved in accordance with IS0 procedures requiring at
least 75 % approval by the member bodies voting.
International Standard IS0 6669 was prepared by Technical Committee ISO/TC 129,
- Aluminium ores.
@ International Organization for Standardization, 1985 l
Printed in Switzerland
---------------------- Page: 2 ----------------------
IS0 6609-1985 (E)
INTERNATIONAL STANDARD
Determination of iron content -
Aluminium ores -
Titrimetric method
150 ml of phosphoric acid (~20 = 1,70 g/ml) and dilute to
1 Scope and field of application
1 litre.
This International Standard specifies a titrimetric method for
the determination of iron in aluminium ores. The method has
4.5 Tin(ll) chloride, 100 g/l solution.
been chosen to avoid interference from platinum which may
occur with the use of platinum crucibles in the acid decomposi-
Place 20 ml of the hydrochloric acid (4.2) into a 100 ml beaker
tion procedure.
and add 10 g of crystalline tin(ll) chloride (SnC12m2H,0). Heat
gently while stirring until the solution is clear. Cool the solution
The method is suitable for use with ores having iron oxide con-
rapidly and dilute to 100 ml.
tents between 2 and 50 % (m/m).
Store this solution in a brown glass bottle with the addition of a
small quantity of granular tin metal.
2 Reference
4.6 MercuryUl) chloride, 40 g/l solution.
IS0 5725, Precision of test methods - Determination of
repea tabifity and reproducibility by inter-laboratory tests. Dissolve 40 g mercury(ll) chloride in water and dilute to 1 litre.
4.7 Ammonium iron(lll) sulfate, standard volumetric sol-
ution.
3 Principle
Decomposition of the test portion by sintering with sodium 4.7.1 Preparation of the solution
peroxide followed by a brief fusion. Dissolution of the fusion
mixture with water and hydrochloric acid. Determination of Dissolve 47,5 g of ammonium iron(lll) sulfate - 24 water
iron by titration with potassium dichromate after reduction with
[Fe2(NH4)2(S04)4m24H201 in the sulfuric acid solution (4.3).
tin(ll) chloride, and oxidation of excess reductant with mer- Transfer to a 1 000 ml one-mark volumetric flask and dilute to
cury(ll) chloride.
the mark with the same acid.
4.7.2 Standardization of the solution
4 Reagents
Pipette 10 ml of the ammonium iron(lll) sulfate solution (4.7.1)
into a 460 ml beaker and dilute to about 80 ml. Add 10 ml of the
During the analysis, use only reagents of recognized analytical
hydrochloric acid (4.2). Boil gently and add the tin(ll) chloride
reagent grade and only distilled water or water of equivalent
solution (4.5), drop by drop, whilst stirring the solution, until
purity.
the yellow colour disappears. Add 1 to 3 drops of excess. Cool
rapidly in a water bath. Add, all at once, 10 ml of the
4.1 Sodium peroxide.
mercury(ll) chloride solution (4.6), mix gently and allow to
stand for 5 min.
NOTE - Sodium peroxide should be protected against humidity and
should not be used once it has begun to agglomerate.
Dilute to approximately 150 ml. Add 30 ml of the sulfuric acid-
phosphoric acid mixture (4.4) and 5 drops of the indicator (4.9),
4.2 Hydrochloric acid, e20 = 1,17 g/ml.
then titrate with the standard potassium dichromate solution
(4.8) to a permanent violet end-point (30 s). Record the volume
of potassium dichromate solution used ( V,).
4.3 Sulfuric acid, e20 = 184 g/ml, diluted 1 + 19.
NOTE - In the absence of iron the diphenylaminesulphonate indicator
4.4 Sulfuric acid-phosphoric acid mixture
does not react with the dichromate solution. The addition of am-
monium iron(lll) sulfate solution is therefore necessary to promote in-
Cautiously pour 150 ml of sulfuric acid (e20 = 184 g/ml) into dicator response in the blank solution, and thus allow a suitable correc-
about 300 ml of water while stirring. Cool in a water bath, add tion for the blank.
---------------------- Page: 3 ----------------------
IS0 6609-1985 (E)
7.2 Test portion
4.8 Potassium dichromate, standard solution,
c(K2Cr207) = 0,016 67 mol/l.
Weigh, to the nearest 0,000 1 g, approximately O/l0 g of test
sample into a zirconium crucible and record the mass (m,).
Dry about 6 g of finely powdered potassium dichromate in an
air oven at 140 to 150 OC for 30 to 60 min. Cool in a closed
vessel. Weigh 4,904 g, dissolve in water, and dilute to the mark
in a 1 000 ml one-mark volumetric flask.
7.3 Blank test
1 ml of 0,016 67 mol/l K&r207 ~0,005 585 g of Fe
In parallel with the decomposition of the test portion, prepare a
blank test solution according to the method of decomposition,
1 ml of 0,016 67 mol/l K&r207 ~0,007 985 g of Fe203
but omitting the test portion. When the analysis is carried out
on several samples at the same time, the blank value may be
represented by one test, provided that the procedure is the
4.9 Barium diphenylaminesulfonate solution.
same and the reagents used are from the same bottles.
Dissolve 0,2 g of barium diphenylaminesulfonate
[(CeH5NHCeH4SOs)2Ba] in a small volume of hot water and
dilute to 100 ml. Store in a cool, dark place. Discard when 7.4 Check test
discoloured.
In each run, one analysis of a certified reference material of the
same type of ore shall be carried out in parallel and under the
same conditions with the analysis of one ore sample.
5 Apparatus
NOTE - The certified reference material should be of the same type as
Ordinary laboratory apparatus, and
the sample to be analysed. Such certified reference materials cannot,
however, be considered as being of the same type if the properties of
5.1 Microburette, 10 ml, class A.
the sample to be analysed differ from those of the certified reference
material to such an extent that the analytical procedure must be
changed substantially.
5.2 Zirconium c
...
SLOVENSKI STANDARD
SIST ISO 6609:2000
01-junij-2000
$OXPLQLMHYHUXGH'RORþHYDQMHFHORWQHJDåHOH]D7LWULPHWULMVNDPHWRGD
Aluminium ores -- Determination of iron content -- Titrimetric method
Minerais alumineux -- Dosage du fer -- Méthode titrimétrique
Ta slovenski standard je istoveten z: ISO 6609:1985
ICS:
73.060.40 Aluminijeve rude Aluminium ores
SIST ISO 6609:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ISO 6609:2000
---------------------- Page: 2 ----------------------
SIST ISO 6609:2000
International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION*MElKt(AYHAPO~HAR OPrAHM3ALU4R I-IO CTAH~APTM3A~MM.ORGANISATlON INTERNATIONALE DE NORMALISATION
Aluminium ores - Determination of iron content -
Titrimetric method
Minerals alumineux - Dosage du fer - Mkthode titrim&rique
First edition - 1985-07-01
UDC 553.492 : 543.24 : 546.72 Ref. No. IS0 6609-1985 (E)
Descriptors : minerals and ores, aiuminium ores, chemical analysis, determination of content, iron, volumetric analysis.
Price based on 4 pages
---------------------- Page: 3 ----------------------
SIST ISO 6609:2000
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 technical committees. Each member
body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the IS0 Council. They are approved in accordance with IS0 procedures requiring at
least 75 % approval by the member bodies voting.
International Standard IS0 6669 was prepared by Technical Committee ISO/TC 129,
- Aluminium ores.
@ International Organization for Standardization, 1985 l
Printed in Switzerland
---------------------- Page: 4 ----------------------
SIST ISO 6609:2000
IS0 6609-1985 (E)
INTERNATIONAL STANDARD
Determination of iron content -
Aluminium ores -
Titrimetric method
150 ml of phosphoric acid (~20 = 1,70 g/ml) and dilute to
1 Scope and field of application
1 litre.
This International Standard specifies a titrimetric method for
the determination of iron in aluminium ores. The method has
4.5 Tin(ll) chloride, 100 g/l solution.
been chosen to avoid interference from platinum which may
occur with the use of platinum crucibles in the acid decomposi-
Place 20 ml of the hydrochloric acid (4.2) into a 100 ml beaker
tion procedure.
and add 10 g of crystalline tin(ll) chloride (SnC12m2H,0). Heat
gently while stirring until the solution is clear. Cool the solution
The method is suitable for use with ores having iron oxide con-
rapidly and dilute to 100 ml.
tents between 2 and 50 % (m/m).
Store this solution in a brown glass bottle with the addition of a
small quantity of granular tin metal.
2 Reference
4.6 MercuryUl) chloride, 40 g/l solution.
IS0 5725, Precision of test methods - Determination of
repea tabifity and reproducibility by inter-laboratory tests. Dissolve 40 g mercury(ll) chloride in water and dilute to 1 litre.
4.7 Ammonium iron(lll) sulfate, standard volumetric sol-
ution.
3 Principle
Decomposition of the test portion by sintering with sodium 4.7.1 Preparation of the solution
peroxide followed by a brief fusion. Dissolution of the fusion
mixture with water and hydrochloric acid. Determination of Dissolve 47,5 g of ammonium iron(lll) sulfate - 24 water
iron by titration with potassium dichromate after reduction with
[Fe2(NH4)2(S04)4m24H201 in the sulfuric acid solution (4.3).
tin(ll) chloride, and oxidation of excess reductant with mer- Transfer to a 1 000 ml one-mark volumetric flask and dilute to
cury(ll) chloride.
the mark with the same acid.
4.7.2 Standardization of the solution
4 Reagents
Pipette 10 ml of the ammonium iron(lll) sulfate solution (4.7.1)
into a 460 ml beaker and dilute to about 80 ml. Add 10 ml of the
During the analysis, use only reagents of recognized analytical
hydrochloric acid (4.2). Boil gently and add the tin(ll) chloride
reagent grade and only distilled water or water of equivalent
solution (4.5), drop by drop, whilst stirring the solution, until
purity.
the yellow colour disappears. Add 1 to 3 drops of excess. Cool
rapidly in a water bath. Add, all at once, 10 ml of the
4.1 Sodium peroxide.
mercury(ll) chloride solution (4.6), mix gently and allow to
stand for 5 min.
NOTE - Sodium peroxide should be protected against humidity and
should not be used once it has begun to agglomerate.
Dilute to approximately 150 ml. Add 30 ml of the sulfuric acid-
phosphoric acid mixture (4.4) and 5 drops of the indicator (4.9),
4.2 Hydrochloric acid, e20 = 1,17 g/ml.
then titrate with the standard potassium dichromate solution
(4.8) to a permanent violet end-point (30 s). Record the volume
of potassium dichromate solution used ( V,).
4.3 Sulfuric acid, e20 = 184 g/ml, diluted 1 + 19.
NOTE - In the absence of iron the diphenylaminesulphonate indicator
4.4 Sulfuric acid-phosphoric acid mixture
does not react with the dichromate solution. The addition of am-
monium iron(lll) sulfate solution is therefore necessary to promote in-
Cautiously pour 150 ml of sulfuric acid (e20 = 184 g/ml) into dicator response in the blank solution, and thus allow a suitable correc-
about 300 ml of water while stirring. Cool in a water bath, add tion for the blank.
---------------------- Page: 5 ----------------------
SIST ISO 6609:2000
IS0 6609-1985 (E)
7.2 Test portion
4.8 Potassium dichromate, standard solution,
c(K2Cr207) = 0,016 67 mol/l.
Weigh, to the nearest 0,000 1 g, approximately O/l0 g of test
sample into a zirconium crucible and record the mass (m,).
Dry about 6 g of finely powdered potassium dichromate in an
air oven at 140 to 150 OC for 30 to 60 min. Cool in a closed
vessel. Weigh 4,904 g, dissolve in water, and dilute to the mark
in a 1 000 ml one-mark volumetric flask.
7.3 Blank test
1 ml of 0,016 67 mol/l K&r207 ~0,005 585 g of Fe
In parallel with the decomposition of the test portion, prepare a
blank test solution according to the method of decomposition,
1 ml of 0,016 67 mol/l K&r207 ~0,007 985 g of Fe203
but omitting the test portion. When the analysis is carried out
on several samples at the same time, the blank value may be
represented by one test, provided that the procedure is the
4.9 Barium diphenylaminesulfonate solution.
same and the reagents used are from the same bottles.
Dissolve 0,2 g of barium diphenylaminesulfonate
[(CeH5NHCeH4SOs)2Ba] in a small volume of hot water and
dilute to 100 ml. Store in a cool, dark place. Discard when 7.4 Check test
discoloured.
In each run, one analysis of a certified reference material of the
same type of ore shall be carried out in parallel and under the
same conditions with the analysis of one ore sa
...
SLOVENSKI STANDARD
SIST ISO 6609:2000
01-junij-2000
$OXPLQLMHYHUXGH'RORþHYDQMHFHORWQHJDåHOH]D7LWULPHWULMVNDPHWRGD
Aluminium ores -- Determination of iron content -- Titrimetric method
Minerais alumineux -- Dosage du fer -- Méthode titrimétrique
Ta slovenski standard je istoveten z: ISO 6609:1985
ICS:
73.060.40 Aluminijeve rude Aluminium ores
SIST ISO 6609:2000 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ISO 6609:2000
---------------------- Page: 2 ----------------------
SIST ISO 6609:2000
International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION*MElKt(AYHAPO~HAR OPrAHM3ALU4R I-IO CTAH~APTM3A~MM.ORGANISATlON INTERNATIONALE DE NORMALISATION
Aluminium ores - Determination of iron content -
Titrimetric method
Minerals alumineux - Dosage du fer - Mkthode titrim&rique
First edition - 1985-07-01
UDC 553.492 : 543.24 : 546.72 Ref. No. IS0 6609-1985 (E)
Descriptors : minerals and ores, aiuminium ores, chemical analysis, determination of content, iron, volumetric analysis.
Price based on 4 pages
---------------------- Page: 3 ----------------------
SIST ISO 6609:2000
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 technical committees. Each member
body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the IS0 Council. They are approved in accordance with IS0 procedures requiring at
least 75 % approval by the member bodies voting.
International Standard IS0 6669 was prepared by Technical Committee ISO/TC 129,
- Aluminium ores.
@ International Organization for Standardization, 1985 l
Printed in Switzerland
---------------------- Page: 4 ----------------------
SIST ISO 6609:2000
IS0 6609-1985 (E)
INTERNATIONAL STANDARD
Determination of iron content -
Aluminium ores -
Titrimetric method
150 ml of phosphoric acid (~20 = 1,70 g/ml) and dilute to
1 Scope and field of application
1 litre.
This International Standard specifies a titrimetric method for
the determination of iron in aluminium ores. The method has
4.5 Tin(ll) chloride, 100 g/l solution.
been chosen to avoid interference from platinum which may
occur with the use of platinum crucibles in the acid decomposi-
Place 20 ml of the hydrochloric acid (4.2) into a 100 ml beaker
tion procedure.
and add 10 g of crystalline tin(ll) chloride (SnC12m2H,0). Heat
gently while stirring until the solution is clear. Cool the solution
The method is suitable for use with ores having iron oxide con-
rapidly and dilute to 100 ml.
tents between 2 and 50 % (m/m).
Store this solution in a brown glass bottle with the addition of a
small quantity of granular tin metal.
2 Reference
4.6 MercuryUl) chloride, 40 g/l solution.
IS0 5725, Precision of test methods - Determination of
repea tabifity and reproducibility by inter-laboratory tests. Dissolve 40 g mercury(ll) chloride in water and dilute to 1 litre.
4.7 Ammonium iron(lll) sulfate, standard volumetric sol-
ution.
3 Principle
Decomposition of the test portion by sintering with sodium 4.7.1 Preparation of the solution
peroxide followed by a brief fusion. Dissolution of the fusion
mixture with water and hydrochloric acid. Determination of Dissolve 47,5 g of ammonium iron(lll) sulfate - 24 water
iron by titration with potassium dichromate after reduction with
[Fe2(NH4)2(S04)4m24H201 in the sulfuric acid solution (4.3).
tin(ll) chloride, and oxidation of excess reductant with mer- Transfer to a 1 000 ml one-mark volumetric flask and dilute to
cury(ll) chloride.
the mark with the same acid.
4.7.2 Standardization of the solution
4 Reagents
Pipette 10 ml of the ammonium iron(lll) sulfate solution (4.7.1)
into a 460 ml beaker and dilute to about 80 ml. Add 10 ml of the
During the analysis, use only reagents of recognized analytical
hydrochloric acid (4.2). Boil gently and add the tin(ll) chloride
reagent grade and only distilled water or water of equivalent
solution (4.5), drop by drop, whilst stirring the solution, until
purity.
the yellow colour disappears. Add 1 to 3 drops of excess. Cool
rapidly in a water bath. Add, all at once, 10 ml of the
4.1 Sodium peroxide.
mercury(ll) chloride solution (4.6), mix gently and allow to
stand for 5 min.
NOTE - Sodium peroxide should be protected against humidity and
should not be used once it has begun to agglomerate.
Dilute to approximately 150 ml. Add 30 ml of the sulfuric acid-
phosphoric acid mixture (4.4) and 5 drops of the indicator (4.9),
4.2 Hydrochloric acid, e20 = 1,17 g/ml.
then titrate with the standard potassium dichromate solution
(4.8) to a permanent violet end-point (30 s). Record the volume
of potassium dichromate solution used ( V,).
4.3 Sulfuric acid, e20 = 184 g/ml, diluted 1 + 19.
NOTE - In the absence of iron the diphenylaminesulphonate indicator
4.4 Sulfuric acid-phosphoric acid mixture
does not react with the dichromate solution. The addition of am-
monium iron(lll) sulfate solution is therefore necessary to promote in-
Cautiously pour 150 ml of sulfuric acid (e20 = 184 g/ml) into dicator response in the blank solution, and thus allow a suitable correc-
about 300 ml of water while stirring. Cool in a water bath, add tion for the blank.
---------------------- Page: 5 ----------------------
SIST ISO 6609:2000
IS0 6609-1985 (E)
7.2 Test portion
4.8 Potassium dichromate, standard solution,
c(K2Cr207) = 0,016 67 mol/l.
Weigh, to the nearest 0,000 1 g, approximately O/l0 g of test
sample into a zirconium crucible and record the mass (m,).
Dry about 6 g of finely powdered potassium dichromate in an
air oven at 140 to 150 OC for 30 to 60 min. Cool in a closed
vessel. Weigh 4,904 g, dissolve in water, and dilute to the mark
in a 1 000 ml one-mark volumetric flask.
7.3 Blank test
1 ml of 0,016 67 mol/l K&r207 ~0,005 585 g of Fe
In parallel with the decomposition of the test portion, prepare a
blank test solution according to the method of decomposition,
1 ml of 0,016 67 mol/l K&r207 ~0,007 985 g of Fe203
but omitting the test portion. When the analysis is carried out
on several samples at the same time, the blank value may be
represented by one test, provided that the procedure is the
4.9 Barium diphenylaminesulfonate solution.
same and the reagents used are from the same bottles.
Dissolve 0,2 g of barium diphenylaminesulfonate
[(CeH5NHCeH4SOs)2Ba] in a small volume of hot water and
dilute to 100 ml. Store in a cool, dark place. Discard when 7.4 Check test
discoloured.
In each run, one analysis of a certified reference material of the
same type of ore shall be carried out in parallel and under the
same conditions with the analysis of one ore sampl
...
Norme internationale
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.ME)I(~YHAPO~HAR OPf-AHM3AL&lR Il0 CTAHJJAPTM3AWWl*ORGANISATION INTERNATIONALE DE NORMALISATION
Minerais alumineux - Dosage du fer - Méthode
titrimétrique
Determina tion of lion content - Titrimetric method
Aluminium ores -
Première édition - 1985-07-01
Réf. no : ISO 6609-1985 (F)
CDU 553.492 : 543.24 : 546.72
iî
-
Descripteurs : minéral, minerai d’aluminium, analyse chimique, dosage, fer, méthode volumétrique.
Prix basé sur 4 pages
---------------------- Page: 1 ----------------------
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale
d’organismes nationaux de normalisation (comités membres de I’ISO). L’élaboration
des Normes internationales est confiée aux comités techniques de I’ISO. Chaque
comité membre intéressé par une étude a le droit de faire partie du comité technique
créé à cet effet. Les organisations internationales, gouvernementales et non gouverne-
mentales, en liaison avec I’ISO, participent également aux travaux.
Les projets de Normes internationales adoptés par les comités techniques sont soumis
aux comités membres pour approbation, avant leur acceptation comme Normes inter-
nationales par le Conseil de I’ISO. Les Normes internationales sont approuvées confor-
mément aux procédures de I’ISO qui requiérent l’approbation de 75 % au moins des
comités membres votants.
- La Norme internationale ISO 6609 a été élaborée par le comité technique ISO/TC 129,
Minerais alumineux.
0 Organisation internationale de normalisation, 1985
Imprimé en Suisse
---------------------- Page: 2 ----------------------
.NORME INTERNATIONALE ISO 66094985 (FI
Minerais alumineux - Dosage du fer - Méthode
titrimétrique
1 Objet et domaine d’application 4.5 Chlorure d’étain(ll), solution à 100 g/l.
La présente Norme internationale spécifie une méthode titrimé- Introduire 20 ml d’acide chlorhydrique (4.2) dans un bécher de
trique de dosage du fer dans les minerais alumineux. La 10 g de chlorure d’étainUl) cristallin
100 ml et ajouter
méthode a été choisie pour éviter l’interférence du platine, qui (SnC12,2H20). Chauffer doucement, en agitant, jusqu’à ce que
peut se produire du fait de l’utilisation de creusets en platine la solution soit claire. Refroidir rapidement la solution et diluer à
dans le mode opératoire de mise en solution acide. 100 ml.
La méthode est applicable aux minerais dont les teneurs en Conserver cette solution dans une bouteille en verre marron
oxyde de fer sont comprises entre 2 et 50 % (mlm). avec l’addition d’une petite quantité de granulés d’étain métal.
4.6 Chlorure de mercure( solution à 40 g/l.
2 Référence
Dissoudre 40 g de chlorure de mercure dans de l’eau et
ISO 5725, Fidélit des méthodes d’essai - Détermination de la
*
diluer à 1 litre.
répé tabilith et de la reproduc tibiljté par essais in terlabora toires.
4.7 Sulfate de fer(lll) et d’ammonium, solution titrée.
3 Principe
4.7.1 Préparation de la solution
Mise en solution de la prise d’essai par frittage au peroxyde de
sodium, suivi d’une brève fusion. Dissolution du mélange
Dissoudre 47,5 g de sulfate de fer(lll) et d’ammonium à
fondu avec de l’eau et de l’acide chlorhydrique. Dosage du fer
24 molécules d’eau [Fe2(NH4)2(S04)4,24H20] dans de la solu-
par titrage au dichromate de potassium aprés réduction au
tion d’acide sulfurique (4.3). Transvaser dans une fiole jaugée
chlorure d’étainUl), et oxydation de l’excès de réducteur avec
de 1 000 ml et diluer au volume avec le même acide.
du chlorure de mercure(
4.7.2 Étalonnage de la solution
4 Réactifs
Pipetter 10 ml de la solution de sulfate de fer(lll) et d’ammo-
nium (4.7.1) dans un bécher de 400 ml et diluer à environ 80 ml.
Au cours de l’analyse, utiliser uniquement des réactifs de qua-
Ajouter 10 ml d’acide chlorhydrique (4.2). Porter doucement à
lité analytique reconnue, et de l’eau distillée ou de l’eau de
ébullition et ajouter, goutte à goutte, de la solution de chlorure
pureté équivalente.
d’étainill) (4.5), en agitant la solution, jusqu’à ce que la couleur
jaune disparaisse, puis ajouter 1 à 3 gouttes en excès. Refroidir
4.1 Peroxyde de sodium.
rapidement dans un bain d’eau. Ajouter, en une seule fois,
10 ml de la solution de chlorure de mercure (4.6), mélanger
NOTE - Le peroxyde de sodium doit être conservé à l’abri de I’humi-
doucement et laisser reposer pendant 5 min.
dite et ne doit pas être utilisé lorsqu’il commence à s’agglomérer.
Diluer à environ 150 ml. Ajouter 30 ml du mélange acide
4.2 Acide chlorhydrique, ezo = 1,17 g/mI.
sulfurique-acide phosphorique (4.4) et 5 gouttes d’indicateur
(4.9), puis titrer avec la solution étalon de dichromate de potas-
sium (4.8) jusqu’à l’obtention d’une teinte violette permanente
4.3 Acide sulfurique ezo = 1,84 g/ml, dilué 1 + 19.
(30 s). Enregistrer le volume de solution de dichromate de
potassium utilisé ( VI).
4.4 Mélange acide sulfurique-acide phosphorique
NOTE - En l’absence de fer, l’indicateur diphénylaminesulfonate ne
Verser avec précaution 150 ml d’acide sulfurique
doit pas réagir avec la solution de dichromate. L’addition de solution de
= 1,84 g/ml) dans environ 300 ml d’eau, en agitant.
(820 sulfate de fer(lll) et d’ammonium est par conséquent nécessaire pour
Refroidir dans un bain d’eau, ajouter 150 ml d’acide phosphori-
faciliter la réponse de l’indicateur dans la solution à blanc, et ainsi per-
1,70 g/ml) et diluer à 1 litre.
mettre une correction appropriée du blanc.
que (820 =
1
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ISO 6609-1985 (F)
4.8 Dichromate de potassium, solution étalon, 7.2 Prise d’essai
= 0,016 67 mol/l.
ci K$&O+
Peser, à 0,000 1 g près, environ 040 g de l’échantillon pour
Sécher environ 6 g de poudre fine de dichromate de potassium essai dans un creuset en zirconium et enregistrer la masse (ml).
dans une étuve aérée entre 140 et 150 OC pendant 30 à 60 min.
Refroidir dans un vase fermé. Peser 4,904 g, dissoudre dans de
7.3 Essai à blanc
l’eau et diluer à 1 000 ml dans une fiole jaugée.
Parallèlement à la mise en solution de la prise d’essai, préparer
1 ml de 0,016 67 mol/1 K2Cr207 ~~0,005 585 g de Fe
une solution à blanc selon la méthode de mise en solution, mais
sans la prise d’essai. Lorsqu’on effectue l’analyse sur plusieurs
1 ml de 0,016 67 mol/1 K2Cr207 ~0,007 985 g de Fe203
échantillons en même temps, la valeur de l’essai à blanc peut
être obtenue par un seul essai, pourvu que le mode opératoire
soit le même et que les réactifs proviennent des mêmes flacons.
4.9 Diphénylaminesulfonate de baryum, solution.
Dissoudre 0,2 g de diphénylaminesulfonate de baryum
7.4 Essai de contrôle
c
[(CôH,NHC6H4S03)2Bal dans un petit volume d’eau chaude et
diluer à 100 ml. Conserver dans un endroit frais et sombre.
À chaque fois, une analyse d’un matériau de référence certifié
Rejeter en cas de décoloration.
du même type de minerai doit être effectuée parallèlement à
l’analyse d’un échantillon de minerai et dans les mêmes condi-
tions.
5 Appareillage
NOTE - Le matériau de référence certifié devrait être du même type
Matériel courant de laboratoire, et
que l’échantillon à analyser. Un tel matériau de référence certifié ne
peut, cependant, être considéré comme étant du même type si les pro-
priétés de l’échantillon à analyser différent de celles du matériau de
5.1 Microburette, de 10 ml, classe A.
référence certifié à un point tel que le mode opératoire analytique doit
être substantiellement modifié.
5.2 Creusets en
...
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