ISO 12742:2020

INTERNATIONAL ISO
STANDARD 12742
Third edition
2020-12
Copper, lead and zinc sulfide
concentrates — Determination of
transportable moisture limits — Flow-
table method
Concentrés sulfurés de cuivre, de plomb et de zinc — Détermination
des limites d'humidité transportable — Méthode de la table
d'écoulement
Reference number
©
ISO 2020
© ISO 2020
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ii © ISO 2020 – 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 Apparatus . 2
6 Sampling and sample preparation . 3
6.1 General . 3
6.2 Laboratory sample . 3
6.3 Sample preparation . 4
7 Procedure. 4
7.1 General . 4
7.2 Preparation of test portions . 4
7.2.1 General. 4
7.2.2 Filling the mould . 5
7.2.3 Tamping pressure . 5
7.2.4 Tamping procedure . 5
7.2.5 Removal of the mould . 6
7.2.6 Dropping the flow table . 6
7.3 Identification of the flow state . 6
7.4 Preliminary flow moisture point . 8
7.4.1 Preparation of test portion . 8
7.4.2 Determination of preliminary flow moisture point . 8
7.4.3 Addition of water for preliminary flow moisture point test . 9
7.4.4 Treatment of sample received above the flow moisture point . 9
7.5 Main flow moisture point determination. 9
7.5.1 Preparation of test portions . 9
7.5.2 Determination of main flow moisture point . 9
7.5.3 Addition of water for main flow moisture point determination. 9
7.6 Graphical method .10
7.6.1 Preparation of test portions .10
7.6.2 Determination of flow moisture point .10
7.7 Moisture determination .10
8 Expression of results .10
8.1 Main flow moisture point .10
8.2 Flow moisture point determined by the graphical method .11
9 Validation of main flow moisture point .11
10 Test report .11
Annex A (normative) Description of equipment used to determine TML .12
Bibliography .21
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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www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 183, Copper, lead, zinc and nickel ores and
concentrates.
This third edition cancels and replaces the second edition (ISO 12742:2007), which has been technically
revised. The main changes to the previous edition are as follows:
— Clause 3, 'Terms and definitions', added.
— 6.2: reference to 7.4.4 for partial drying in event that sample received above transportable moisture
limit (TML) added.
— Clause 6: reference to ISO 12743 sampling procedures added.
— 7.3: description of the flow state changed for clarity.
— 7.4.2: permission to deviate from the sample mass requirements of ISO 10251 for moisture
determination added.
— 7.4.4: procedure for partial drying of sample received above TML added.
— 7.6.1: inclusion of data points with greater than 12 mm displacements in the graphical method
provided that the points fall on the linear portion of the graph.
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.
iv © ISO 2020 – All rights reserved

Introduction
The first edition of this document was published in 2000 as a guidance document because there had
been insufficient test programme participants to allow precision data to be derived.
The second edition included the addition of the graphical method for determination of the flow point as
a means of validating the bracket method. This version has been revised to make it easier to understand
and follow.
INTERNATIONAL STANDARD ISO 12742:2020(E)
Copper, lead and zinc sulfide concentrates —
Determination of transportable moisture limits — Flow-
table method
WARNING — This document could involve hazardous materials, operations and equipment.
It is the responsibility of the user of this document to establish appropriate health and safety
practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This document specifies a flow-table method for the determination of the transportable moisture limit
(TML) of copper, lead and zinc sulfide concentrates, which can liquefy during transport.
It is applicable to the determination of the TML of concentrates containing 10 % to 80 % (mass fraction)
of lead, 10 % to 65 % (mass fraction) of zinc or 10 % to 55 % (mass fraction) of copper and is applicable
to TML values in the range 3 % to 28 % (mass fraction).
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 10251, Copper, lead, zinc and nickel concentrates — Determination of mass loss of bulk material on drying
ISO 12743, Copper, lead, zinc and nickel concentrates — Sampling procedures for determination of metal
and moisture content
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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/
3.1
flow moisture point
percentage of moisture at which a flow state is reached
3.2
transportable moisture limit
maximum percentage of moisture that a cargo can contain during transport without the risk of
liquefaction
4 Principle
The moisture content of the sample is adjusted by mixing with water. The mixture is converted to
a conical shape using a mould and tamper. The sample is placed on the flow table and the mould is
removed. The flow characteristics are determined by repeated dropping of the flow table while
observing the behaviour of the sample. When sufficient water has been added to the sample so that
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