ISO 7215:2007

INTERNATIONAL ISO
STANDARD 7215
Third edition
2007-10-15

Iron ores for blast furnace feedstocks —
Determination of the reducibility by the
final degree of reduction index
Minerais de fer pour charges de hauts fourneaux — Détermination de la
réductibilité relative par le degré final de l'indice de réduction




Reference number
ISO 7215:2007(E)
©
ISO 2007

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ISO 7215:2007(E)
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ii © ISO 2007 – All rights reserved

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ISO 7215:2007(E)
Contents Page
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
6 Apparatus . 2
7 Test conditions . 3
8 Procedure . 4
9 Expression of results . 5
10 Test report . 6
11 Verification . 6
Annex A (normative) Flowsheet of the procedure for the acceptance of test results . 9
Annex B (informative) Derivation of the equation for final degree of reduction. 10

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ISO 7215:2007(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 committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 7215 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee
SC 3, Physical testing.
This third edition cancels and replaces the second edition (ISO 7215:1995), which has been revised to
homogenise with other physical test standards.
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ISO 7215:2007(E)
Introduction
This International Standard 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 different laboratories.
The results of this test should be considered in conjunction with other tests used to evaluate the quality of iron
ores as feedstocks for blast furnace processes.
This International Standard may be used to provide test results as part of a production quality control system,
as a basis of a contract, or as part of a research project.

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INTERNATIONAL STANDARD ISO 7215:2007(E)

Iron ores for blast furnace feedstocks — Determination of the
reducibility by the final degree of reduction index
CAUTION — This International Standard may involve hazardous materials, operations and equipment.
This standard does not purport to address all of the safety issues associated with its use. It is the
responsibility of the user of this International Standard to establish appropriate safety and health
practices and determine the applicability of regulatory limitations prior to its use.
1 Scope
This International Standard specifies a method to provide a relative measure for evaluating the extent to which
oxygen can be removed from iron ores when reduced under conditions resembling those prevailing in the
reduction zone of a blast furnace.
This International Standard is applicable to lump ores, sinters and hot-bonded pellets.
2 Normative references
The following referenced documents are indispensable for the application 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 2597-1:2006, Iron ores — Determination of total iron content — Part 1: Titrimetric method after tin(II)
chloride reduction
1)
ISO 3082:2000 , Iron ores — Sampling and sample preparation procedures
ISO 9035:1989, Iron ores — Determination of acid-soluble iron(II) content — Titrimetric method
ISO 9507:1990, Iron ores — Determination of total iron content — Titanium(III) chloride reduction methods
ISO 11323:2002, Iron ore and direct reduced iron — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11323 apply.
4 Principle
The test portion is isothermally reduced in a fixed bed, at 900 °C, using a reducing gas consisting of CO and
N , for 180 min. The degree of reduction is calculated from the oxygen mass loss after 180 min.
2

1) Under revision to incorporate ISO 10836, Iron ores — Method of sampling and sample preparation for physical testing.
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ISO 7215:2007(E)
5 Sampling, sample preparation and preparation of test portions
5.1 Sampling and sample preparation
Sampling of a lot and preparation of a test sample shall be in accordance with ISO 3082.
The size range for pellets shall be −12,5 mm +10,0 mm.
The size range for sinters and lump ores shall be −20,0 mm +18,0 mm.
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
preparation of the test portions.
NOTE Constant mass is achieved when the difference in mass between two subsequent measurements becomes
less than 0,05 % of the initial mass of the test sample.
5.2 Preparation of test portions
Collect each test portion by taking ore particles at random.
NOTE Manual methods of division recommended in ISO 3082, such as riffling, can be applied to obtain the test
portions.
At least 5 test portions, each of approximately 500 g mass (± the mass of 1 particle) shall be prepared from
the test sample: 4 test portions for testing and 1 for chemical analysis.
Weigh the test portions to the nearest 1 g and register the mass of each test portion on its recipient label.
6 Apparatus
6.1 General
The test apparatus shall comprise:
a) ordinary laboratory equipment, such as an oven, hand tools, time-control device and safety equipment;
b) a reduction-tube assembly;
c) a furnace, equipped with a balance for permitting the mass loss of the test portion to be read at any time
during the test;
d) a system to supply the gases and regulate the flow rates;
e) a weighing device.
Figure 1 shows an example of the test apparatus.
6.2 Reduction tube, made of non-scaling, heat-resistant metal to withstand temperatures higher than
900 °C and resistant to deformation. The internal diameter shall be 75 mm ± 1 mm. A removable perforated
plate, made of non-sc
...