ISO/DIS 4298

Manganese ores and concentrates -- Determination of manganese content -- Potentiometric method

Minerais et concentrés de manganèse -- Dosage du manganèse -- Méthode potentiométrique

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 4298
ISO/TC 132 Secretariat: SAC
Voting begins on: Voting terminates on:
2021-02-01 2021-04-26
Manganese ores and concentrates — Determination of
manganese content — Potentiometric method

Minerais et concentrés de manganèse — Dosage du manganèse — Méthode potentiométrique

ICS: 73.060.20
THIS DOCUMENT IS A DRAFT CIRCULATED
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ISO/DIS 4298:2021(E)
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PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
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ISO/DIS 4298:2021(E)
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ISO/DIS 4298:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Principle ........................................................................................................................................................................................................................ 1

4 Reaction ......................................................................................................................................................................................................................... 1

5 Reagents ........................................................................................................................................................................................................................ 1

6 Apparatus ..................................................................................................................................................................................................................... 4

6.1 Potentiometric titration apparatus ....................................................................................................................................... 4

6.2 Platinum crucible .................................................................................................................................................................................. 4

6.3 Filter crucible with a sintered glass plate No.3 ........................................................................................................... 4

7 Sampling ........................................................................................................................................................................................................................ 4

8 Procedure..................................................................................................................................................................................................................... 4

8.1 Test portion ................................................................................................................................................................................................ 4

8.2 Blank test ..................................................................................................................................................................................................... 5

8.3 Determination of hygroscopic moisture content....................................................................................................... 5

8.4 Decomposition of test portion ................................................................................................................................................... 5

8.5 Treatment of residue ......................................................................................................................................................................... 5

8.6 Titration ........................................................................................................................................................................................................ 5

9 Expression of results ........................................................................................................................................................................................ 5

9.1 Calculation of manganese content ......................................................................................................................................... 5

9.2 General treatment of results ....................................................................................................................................................... 6

9.2.1 Expression of precision .............................................................................................................................................. 6

9.2.2 Determination of analytical result .................................................................................................................... 7

9.2.3 Between-laboratories precision ......................................................................................................................... 7

9.2.4 Check for trueness .......................................................................................................................................................... 8

9.2.5 Calculation of final result .......................................................................................................................................... 8

10 Test report ................................................................................................................................................................................................................... 8

Annex A (normative) The original data of verification test .......................................................................................................10

Annex B (normative) The graphic presentation of the data .....................................................................................................12

Annex C (normative) Flow sheet for the procedure for the acceptance of analytical value for

test samples ............................................................................................................................................................................................................13

Bibliography .............................................................................................................................................................................................................................14

© ISO 2021 – All rights reserved iii
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ISO/DIS 4298:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 132, Ferroalloys.

This third edition cancels and replaces the second edition (ISO 4298:1984), which has been technically

revised with the following changes:

— Clause 2, the description of reaction has been reworded to better explain the method;

— Clause 4, 4 normative references have been added;

— Clause 5, a requirement of reagent used in method has been added in the first paragraph;

— Clause 5, the order of reagents has been renumbered, starting with the commercial reagents and

the prepared reagents backwards;

— Clause 5, “potassium permanganate, degree of purity not less than 99,5 %” has been added as a

reagent, and the description for potassium-permanganate in 5.10 (previously 5.9) has been replaced

with “potassium-permanganate (KMnO ), recrystallized”;

— in 5.11 (previously in 5.10), the detailed specification of “electrolytic manganese” has been added

and described as “electrolytic manganese metal flakes”;

— in 5.12 (previously in 5.11), the commercially available standard solution has been added as an

alternative, and variations in concentration shall be taken into account for the calculation of the

results in 9.1;

— in 5.12.1 (previously 5.11.1), reduce the amount of aliquot portion of the manganese standard

reference solution and the saturated sodium pyrophosphate solution, and change the specification

of the beaker;

— in 5.12.2 (previously 5.11.2), reduce the amount of aliquot portion of the potassium permanganate

solution and the saturated sodium pyrophosphate solution, and change the specification of the beaker;

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ISO/DIS 4298:2021(E)

— in 5.12.1, 5.12.2 and 8.6 (previously in 5.11.1,5.11.2 and 8.4), the sodium pyrophosphate solution

(5.3) has been replaced with “the saturated sodium pyrophosphate solution (5.9)”;

— Clause 6, a requirement of volumetric glassware used in method has been added in the first

paragraph;

— in 6.1, the paragraph of the description of pH meter has been replaced with the paragraph of

potentiometric titration apparatus to in line with the current status of the development of the

instrument, including the description for potentiometric titration in 6.1.1, pH determination in 6.1.2

and titration assembly in 6.1.3;

— Clause 6, filter crucible with a sintered glass plate No.3 has been added as an apparatus;

— Clause 8, a new paragraph of the definition of test portion has been added in 8.1 and reduce the

amount of test portion in 8.1 (previously 8.2) from 1.0 g to 0.50 g;

— Clause 8, a new paragraph of the definition and requirement of determination of hygroscopic

moisture content has been added in 8.3;

— Clause 8, the order of items 8.1, 8.2, 8.3 and 8.4 previously has been renumbered to 8.2, 8.4, 8.5 and 8.6;

— in 8.4 (previously 8.2), reduce the amount of acids, change the times of washing, and add the detailed

usage of watch-glass and the provision of filter volume;

— in 8.5 (previously 8.3), the volume of the filtrate after filtration and the temperature for ashing and

volatilization of alkali salts has been added;

— in 8.6 (previously 8.4), reduce the amount of aliquot portion of the solution and the saturated sodium

pyrophosphate solution and change the specification of one-mark volumetric flask and the beaker;

— in 9.1, the formula of the manganese content has been replaced with three new calculating formulas

which took into account the hygroscopic moisture content of the test portion;

— in 9.2, the paragraph of the “permissible tolerances on results” has been replaced with the “general

treatment of results”;
— Clause 10, the test report has been added;
— “Annex A The original data of verification test” has been added;
— “Annex B The graphic presentation of the data” has been added;

— “Annex C Flow sheet of the procedure for the acceptance of analytical value for teat samples” has

been added;

— Bibliography of ISO 5725-2 and ISO Guide 35 referred in 9.2.1 and 9.2.4 has been inserted at the end

of the document;

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2021 – All rights reserved v
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DRAFT INTERNATIONAL STANDARD ISO/DIS 4298:2021(E)
Manganese ores and concentrates — Determination of
manganese content — Potentiometric method
1 Scope

This International standard specifies a potentiometric method for the determination of the

manganese content of manganese ores and concentrates with manganese content equal to or greater

than 15 % (m/m).
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 310, Manganese ores and concentrates — Determination of hygroscopic moisture content in analytical

samples — Gravimetric method
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1042, Laboratory glassware — One-mark volumetric flasks
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 4296-1, Manganese ores — Sampling — Part 1: Increment sampling
ISO 4296-2, Manganese ores — Sampling — Part 2: Preparation of samples

ISO 4297, Manganese ores and concentrates — Methods of chemical analysis — General instructions

3 Principle

Decomposition of a test portion by treatment with hydrochloric acid, nitric, perchloric and hydrofluoric

acids. Separation of insoluble residue, and reservation of the filtrate as the main solution. Ignition of

the residue, fusion with sodium carbonate, leaching of the melt with hydrochloric acid and combination

with the main solution. Addition of an aliquot portion of the resulting solution to sodium pyrophosphate

solution, adjustment of the pH to 7,0, and potentiometric titration with potassium permanganate

standard volumetric solution.
4 Reaction

The method is based on the titration of manganous ion with permanganate ion in neutral pyrophosphate

solution, the manganese (II) being oxidized, the permanganate ion reduced, to a pyrophosphate complex

2+ −
of the +3 state (the stoichiometry ratio of Mn to MnO is 4:1).
5 Reagents

During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only

grade 3 water as specified in ISO 3696.
5.1 Sodium carbonate (Na CO ), anhydrous.
2 3
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ISO/DIS 4298:2021(E)
5.2 Hydrochloric acid, ρ 1,19 g/ml.
5.3 Hydrofluoric acid, ρ 1,14 g/ml.
5.4 Perchloric acid, ρ 1,51 g/ml.
5.5 Nitric acid, ρ 1,40 g/ml.
5.6 Potassium permanganate, degree of purity not less than 99,5 %.
5.7 Sodium carbonate, 50 g/l solution.
5.8 Hydrochloric acid, diluted 1+4.
5.9 Saturated sodium pyrophosphate solution

Dissolve 120 g of sodium pyrophosphate decahydrate (Na P O ·10H O) with 1 000 ml of water. After 24

4 2 7 2
h, the supernatant is obtained for use.
5.10 Potassium-permanganate (KMnO ), recrystallized.

Dissolve 250 g of potassium permanganate (5.6) with 800 ml of hot water (90 °C) in a 1 000 ml beaker.

Filter the solution under vacuum through a filter crucible with a sintered glass plate No.3 (6.3). Cool the

filtered solution in an ice bath to 10 °C, while stirring vigorously. Allow the fine-grained precipitate to

settle. Then pour out the solution, transfer the crystalline mass to the crucible with sintered glass plate

No.3 (6.3) and place under suction. Repeat the recrystallization.

After thorough suction, transfer the crystalline mass thus obtained to a glass or porcelain dish and

dry in air in the dark, protecting from dust. When the crystalline mass no longer sticks together

when crushed with a glass rod, dry it at 80 to 100 °C for 2 to 3 h in a drying oven. Then transfer it to a

stoppered brown glass bottle.

Potassium permanganate thus obtained contains 34,76 % (m/m) of manganese and is non-hygroscopic.

5.11 Manganese, standard reference solution, corresponding to 1 g of Mn per litre.

Place 10,00 g of electrolytic manganese metal flakes (purity not less than 99,95 %) in a 400 or 500 ml

beaker. Add a mixture of 50 ml of water and 5 ml of the nitric acid (5.5) and leave for a few minutes until

the surface becomes bright. Wash the treated manganese six times with water, then with acetone, and

dry at 100 °C for 10 min.

Place 1,00 g of the treated electrolytic manganese in a 400 or 500 ml beaker, and add 20 ml of sulfuric

acid (ρ 1,84 g/ ml, diluted 1 + 1) and about 100 ml of water. Boil the solution for a few minutes, cool,

transfer to a 1 000 ml one mark volumetric flask, dilute to the mark with water and mix.

1 ml o
...