ISO/FDIS 4695

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 4695
ISO/TC 102/SC 3
Iron ores for blast furnace
Secretariat: ABNT
feedstocks — Determination of the
Voting begins on:
2021­06­01 reducibility by the rate of reduction
index
Voting terminates on:
2021­08-24
Minerais de fer pour charges de hauts fourneaux — Détermination de
la réductibilité à partir de la vitesse de réduction
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 4695:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
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ISO/FDIS 4695:2021(E)
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© ISO 2021

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

Introduction ..................................................................................................................................................................................................................................v

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 1

5 Sampling, sample preparation and preparation of test portions ......................................................................2

5.1 Sampling and sample preparation ......................................................................................................................................... 2

5.2 Preparation of test portions ........................................................................................................................................................ 2

6 Apparatus ..................................................................................................................................................................................................................... 2

7 Test conditions ....................................................................................................................................................................................................... 5

7.1 General ........................................................................................................................................................................................................... 5

7.2 Reducing gas ............................................................................................................................................................................................. 5

7.2.1 Composition ......................................................................................................................................................................... 5

7.2.2 Purity ......................................................................................................................................................................................... 5

7.2.3 Flow rate ................................................................................................................................................................................. 5

7.3 Heating and cooling gas .................................................................................................................................................................. 5

7.4 Temperature of the test portion ............................................................................................................................................... 6

8 Procedure..................................................................................................................................................................................................................... 6

8.1 Number of determinations for the test .............................................................................................................................. 6

8.2 Chemical analysis .................................................................................................................................................................................. 6

8.3 Reduction ..................................................................................................................................................................................................... 6

9 Expression of results ........................................................................................................................................................................................ 7

9.1 Calculation of the reducibility index ................................................................................................................................... 7

9.2 Repeatability and acceptance of test results ................................................................................................................. 8

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

11 Verification ................................................................................................................................................................................................................. 8

Annex A (normative) Flowsheet of the procedure for the acceptance of test results .....................................10

Annex B (informative) Derivation of equation for reducibility .............................................................................................11

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This document was prepared by Technical Committee ISO/TC 201, Iron ore and direct reduced iron,

This fifth edition cancels and replaces the fourth edition (ISO 4695:2015), of which it constitutes a

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

This document concerns one of a number of physical test methods that have been developed to

measure various physical parameters and to evaluate the behaviour of iron ores, including reducibility,

disintegration, crushing strength, apparent density, etc. This method was developed to provide a

uniform procedure, validated by collaborative testing, to facilitate comparisons of tests made in

The results of this test have to be considered in conjunction with other tests used to evaluate the quality

This document can be used to provide test results as part of a production quality control system, as a

CAUTION — This document can involve hazardous operations and equipment. This document

does not purport to address all of the safety issues associated with its use. It is the responsibility

of the user of this document to establish appropriate safety and health practices and determine

This document specifies a method to provide a relative measure for evaluating the extent to and ease

with which oxygen can be removed from iron ores, when reduced under conditions resembling those

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 2597­1, Iron ores — Determination of total iron content — Part 1: Titrimetric method after tin(II)

ISO 2597­2, Iron ores — Determination of total iron content — Part 2: Titrimetric methods after

ISO 9035, Iron ores — Determination of acid-soluble iron(II) content — Titrimetric method

For the purposes of this document, the terms and definitions given in ISO 11323 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

The test portion is isothermally reduced in a fixed bed, at 950 °C, using a reducing gas consisting of CO

and N , and the mass loss of the test portion is recorded continuously or at specified time intervals until

its degree of reduction reaches 65 %. The rate of reduction is calculated at the oxygen/iron ratio of 0,9.

Sampling of a lot and preparation of a test sample shall be in accordance with ISO 3082.

A test sample of at least 2,5 kg, on a dry basis, of the sized material shall be obtained.

Oven-dry the test sample to constant mass at 105 °C ± 5 °C and cool it to room temperature before

NOTE Constant mass is achieved when the difference in mass between two subsequent measurements