ISO 7215:2015

INTERNATIONAL ISO
STANDARD 7215
Fourth edition
2015-08-15
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 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

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 . 1
5.1 Sampling and sample preparation . 1
5.2 Preparation of test portions . 2
6 Apparatus . 2
6.1 General . 2
7 Test conditions . 3
7.1 General . 3
7.2 Reducing gas . 3
7.2.1 Composition . 3
7.2.2 Purity . 3
7.2.3 Flow rate . 3
7.3 Heating and cooling gas . 3
7.4 Temperature of the test portion . 3
8 Procedure. 3
8.1 Number of determinations for the test . 3
8.2 Chemical analysis . 4
8.3 Reduction . 4
9 Expression of results . 5
9.1 Calculation of the degree of reduction (R ) . 5
9.2 Repeatability for R and acceptance of test results . 5
10 Test report . 5
11 Verification . 6
Annex A (normative) Flowsheet of the procedure for the acceptance of test results .9
Annex B (informative) Derivation of the formula for final degree of reduction .10
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
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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
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assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 102, Iron ore and direct reduced iron,
Subcommittee SC 3, Physical testing.
This fourth edition cancels and replaces the third edition (ISO 7215:2007), of which it constitutes a
minor revision to contemplate the outcome of the studies on mass definition, as well as minor editorial
improvements.
iv © ISO 2015 – All rights reserved

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 have to be considered in conjunction with other tests used to evaluate the quality
of iron ores as feedstocks for blast furnace processes.
This International Standard can 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.
INTERNATIONAL STANDARD ISO 7215:2015(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 operations and equipment. This
International 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 ore, sinters, and hot-bonded pellets.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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, Iron ores — Determination of total iron content — Part 1: Titrimetric method after tin(II)
chloride reduction
ISO 2597-2, Iron ores — Determination of total iron content — Part 2: Titrimetric methods after
titanium(III) chloride reduction
ISO 3082, Iron ores — Sampling and sample preparation procedures
ISO 9035, Iron ores — Determination of acid-soluble iron(II) content — Titrimetric method
ISO 11323, 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 final degree of reduction is calculated from the oxygen mass loss after 180 min (R ).
2 180
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.
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