ISO/DIS 4298

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

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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

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

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

— 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

— 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

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

— 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

— 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

— 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;

— 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

— 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

— 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

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

— 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

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

— 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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.