ISO 556:2020

INTERNATIONAL ISO
STANDARD 556
Second edition
2020-03
Coke (greater than 20 mm in size) —
Determination of mechanical strength
Coke (dimension supérieure à 20 mm) — Détermination de la
cohésion
Reference number
ISO 556:2020(E)
©
ISO 2020

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ISO 556:2020(E)

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© ISO 2020
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ISO 556:2020(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 2
6 Sample preparation . 3
7 Procedure. 4
7.1 Test procedure . 4
8 Expression of results . 5
8.1 Calculation . 5
8.2 Micum indices . 5
8.3 Irsid indices . 6
9 Precision of the method . 6
9.1 Repeatability . 6
9.1.1 Number of determinations. 6
9.2 Reproducibility . 7
10 Test report . 7
Annex A (informative) Example of half Micum test report . 9
Bibliography .11
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ISO 556:2020(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
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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).
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on the ISO list of patent declarations received (see www .iso .org/ patents).
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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 27, Solid mineral fuels, Subcommittee
SC 3, Coke.
This second edition cancels and replaces the first edition (ISO 556:1980), which has been technically
revised. The main changes compared to the previous edition are as follows:
a) The sample of coke used for Micum and Irsid tests may be analysed with a bottom size greater than
20 mm (e.g. 40 mm or 60 mm) and should the starting bottom size of coke used be different from
20 mm, it is to be stated in the test report.
b) Addition of a new set of tables specifying:
1) Sample, test conditions and results for Micum and Irsid tests.
2) Dimensions of the cylindrical steel drum for Micum and Irsid tests.
3) Suitable set of sieves.
c) In reporting coke Micum and/or Irsid results, it is required to specify if a single determination or a
duplicate determination was made and if a full or half Micum drum was used.
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.
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INTERNATIONAL STANDARD ISO 556:2020(E)
Coke (greater than 20 mm in size) — Determination of
mechanical strength
1 Scope
This document specifies a method for the determination of the mechanical strength of coke having a
particle size greater than 20 mm.
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 728, Coke (nominal top size greater than 20 mm) — Size analysis by sieving
ISO 18283, Hard coal and coke — Manual sampling
ISO 13909-6, Hard coal and coke — Mechanical sampling — Part 6: Coke — Preparation of test samples
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Principle
A sample of coke greater than 20 mm in size (Micum and Irsid tests) and of known size distribution is
subjected to mechanical stresses in a rotating drum. If desired, a sample of coke may also be analysed
with a bottom size greater than 20 mm (e.g. 40 mm or 60 mm). Should the starting bottom size of coke
used be different from 20 mm, it shall be stated in the test report.
The degree of breakdown of the coke is evaluated by a process of sieving and size analysis after 100
drum revolutions (Micum test) and, if desired, after a total of 500 drum revolutions (Irsid test). Micum
and Irsid tests may be performed on the same coke sample.
Table 1 lists sample and test conditions as well as results in conducting Micum, Irsid and half Micum/
half Irsid tests.
Table 1 — Sample, test conditions and results for Micum and Irsid tests
Test Method
Unit of
Indicator Index
Half Micum or
measurement
Micum Irsid
Half Irsid
Sample Size mm >20, >40, >60 >20, >40, >60 >20, >40, >60
Amount kg 50 ± 0,5 50 ± 0,5 25 ± 0,25
Moisture % <3 <3 <3
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ISO 556:2020(E)

Table 1 (continued)
Test Method
Unit of
Indicator Index
Half Micum or
measurement
Micum Irsid
Half Irsid
Test Revolutions no. 100 (Micum) or
100 500
500 (Irsid)
Rotation Frequency r/min 25 ± 1 25 ± 1 25 ± 1
Results % >40 mm >40 mm >40 mm
>20 mm >20 mm >20 mm
<10 mm <10 mm <10 mm
NOTE  Sieves of 10 mm, 20 mm, and 40 mm are mandatory. Other sieves with different apertures are optional
(see Table 3).
5 Apparatus
5.1 Cylindrical steel drum, having the following dimensions (see Table 2 and Figure 1):
Table 2 — Dimensions of cylindrical steel drum for Micum and Irsid tests
Test Method
Indicator Index Unit of measurement
Half Micum or
Micum Irsid
Half Irsid
Apparatus Inner Length mm 1 000 ± 5 1 000 ± 5 500 ± 5
Inner Diameter mm 1 000 ± 5 1 000 ± 5 1 000 ± 5
Thickness of mm 6 6 6
drum
Lifter no. 4 4 4
Lifter Angle mm 100 × 50 × 10 100 × 50 × 10 100 × 50 × 10
Opening width mm 500 500 500
Opening length mm 500 - 1 000 500 - 1 000 300 - 500
Rotation r/min 25 ± 1 25 ± 1 25 ± 1
Frequency
NOTE  If lifter angles (100 × 50 × 10) mm are not available, it is possible to use (100 × 50 × 8) mm instead.
The drum shall have an opening on the cylindrical surface through which the coke is charged and
discharged. The opening shall be fitted with a cover, the inner portion of which shall be of 10 mm steel
plate of the same curvature as the drum, and which shall be of the same size as the opening so that
when the cover is secured, the inside face is substantially level with the internal surface of the drum. A
rubber gasket should be fitted around the cover to minimize loss of dust.
Inside the drum, parallel to its axis and dividing the wall into four equal areas, four angle sections
(or lifting flights) shall be fixed. Each lifting flight (for dimensions see Table 2), equal in length to the
length of the drum, shall be fixed rigidly to the full length of the internal curved surface of the drum.
The position of the lifting flights is parallel to the axis of the drum in such a way that the flange of
width 100 mm points towards the axis of the drum, and the narrower flange, in contact with the curved
surface of the drum, points in the direction opposite to that of rotation of the drum.
Drum wall thickness and lifting flight thickness should be measured after every 500 tests to ensure
conformity to specifications. The drum shall be replaced if the wall thickness falls below 5 mm due to
wear. The angle sections (or lifting flights) shall be replaced when they wear to 95 mm.
The drum shall be carried on two stub-axles, at least 250 mm in length, rotating in horizontal journal
bearings which are supported in a framework mounted at either side of the drum. The clearance
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ISO 556:2020(E)

below the drum shall be not less than 230 mm and not more than 300 mm to enable the drum to be
conveniently emptied. The drum shall be capable of being rotated in either direction to facilitate
emptying. An electric motor shall be used to set the drum in motion at a constant rotational frequency
−1
of (25 ± 1) min and the drum shall be fitted with a revolution counter and relay system, which may be
pre-set to stop the drum after any desired number of revolutions.
5.2 Tray, >1 000 mm × >900 mm × 200 mm deep, constructed from a suitable abrasion-resistant and
wear-resistant material for receiving the coke on discharge. One end wall of the tray shall be inclined
outwards at 45° to facilitate emptying.
NOTE 1 Trays of approxima
...