ISO 12742:2007

INTERNATIONAL ISO
STANDARD 12742
Second edition
2007-07-01
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 2007
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©  ISO 2007
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ii © ISO 2007 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope .1
2 Normative references .1
3 Principle.1
4 Apparatus .1
5 Sampling and sample preparation.2
5.1 General.2
5.2 Laboratory sample.3
5.3 Sample preparation .3
6 Procedure .3
6.1 General.3
6.2 Preparation of test portions.4
6.2.1 General.4
6.2.2 Filling the mould .4
6.2.3 Tamping pressure.4
6.2.4 Tamping procedure .5
6.2.5 Removal of the mould .5
6.2.6 Dropping the flow table.5
6.3 Identification of the flow state.5
6.4 Preliminary flow moisture point.7
6.4.1 Preparation of test portion.7
6.4.2 Determination of preliminary flow moisture point .7
6.4.3 Addition of water for preliminary flow moisture point test .8
6.5 Main flow moisture point determination .8
6.5.1 Preparation of test portions.8
6.5.2 Determination of main flow moisture point .8
6.5.3 Addition of water for main flow moisture point determination.8
6.6 Graphical method .8
6.6.1 Preparation of test portions.8
6.6.2 Determination of flow moisture point.9
6.7 Moisture determination .9
7 Expression of results .9
7.1 Main flow moisture point .9
7.2 Flow moisture point determined by the graphical method .9
8 Validation of main flow moisture point .10
9 Test report .10
Annex A (normative) Description of equipment used to determine TML.11
Bibliography .18

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 12742 was prepared by Technical Committee ISO/TC 183, Copper, lead, zinc and nickel ores and
concentrates.
This second edition cancels and replaces the first edition (ISO 12742:2000), which has been technically
revised.
iv © ISO 2007 – All rights reserved

Introduction
ISO 12742:2000 was published as a guidance document because there had been insufficient test programme
participants to allow precision data to be derived. However, it had been agreed that ISO/TC 183/WG 11 be
kept in existence, as there was likelihood that a precision test programme could be held at a later time.
Revision of ISO 12742 was commenced in 2005, on the basis that changes to the procedure were necessary,
and there were then sufficient participants to allow a test programme to be conducted.
In the final analysis, insufficient participants were identified. However, the International Standard has been
revised for a further edition as a guidance document.

INTERNATIONAL STANDARD ISO 12742:2007(E)

Copper, lead, and zinc sulfide concentrates — Determination of
transportable moisture limits — Flow-table method
WARNING — This International Standard may involve hazardous materials, operations and equipment.
It is the responsibility of the user of this International Standard to establish appropriate health and
safety practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This International Standard specifies a flow-table method for the determination of the transportable moisture
limit (TML) of copper, lead and zinc sulfide concentrates, which may liquefy during transport.
This International Standard is applicable to the determination of the TML of concentrates containing 10 % to
80 % (mass fraction) of lead, or 10 % to 65 % (mass fraction) of zinc, or 10 % to 55 % (mass fraction) of
copper. It is applicable to TMLs in the range 3 % to 28 % (mass fraction).
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 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 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 plastic deformation occurs during the
dropping of the flow table, the sample is considered to be at its flow moisture point.
The TML is calculated as 90 % of the flow moisture point.
4 Apparatus
Copper, lead and zinc concentrates may gain or lose moisture rapidly when exposed to air. The laboratory
should be designed so that excessive temperatures, direct sunlight, air currents and humidity variations are
avoided.
4.1 Flow table and frame, as specified in Annex A.
The flow-table mounting shall be as specified in Figure A.1.
4.2 Mould, as specified in Figure A.1.
4.3 Tamper.
The required tamping pressure may be achieved by using calibrated, spring-loaded tampers or some other
suitable design of tamper that allows a controlled pressure to be applied via a 30 mm diameter tamper head
as specified in Figure A.2.
4.4 Calliper ruler.
4.5 Balance, top loading, having the sensitivity specified in Table 1.
Table 1 — Sensitivity of balance and precision of weighing
Mass of sample plus tray Precision of balance
and weighing
g g
100 0,01
200 0,02
300 0,03
400 0,04
500 0,05
4.6 Measuring cylinder, of capacity 50 ml to 200 ml.
4.7 Burette, of capacity 10 ml.
4.8 Mixing bowl, hemispherical, of diameter approximately 30 cm.
NOTE It is advisable to use an automatic mechanical mixer having a mixing bowl as described, as this leads to
improved precision.
4.9 Rubber gloves.
4.10 Drying trays or pans, having dimensions that permit the sample to be spread to a thickness of less
than 30 mm.
The trays shall be made of corrosion-resistant and heat-resistant material, such as stainless steel, glass or
enamel plate.
4.11 Drying oven, ventilated, with forced circulation of air or inert gas, regulated at a temperature of
105 °C ± 5 °C.
4.12 Airtight containers.
5 Sampling and sample preparation
5.1 General
TML figures are required to be updated on a periodic basis, usually six monthly, or when there is a known
change to the process used to produce the material. The reported figure should be the mean of samples taken
during the period.
2 © ISO 2007 – All rights reserved

To ensure that the TML result is representative, increments of the material shall be taken either
a) while a stockpile is being built up or broken down, or
b) while loading or discharging a vessel.
These increments are combined to form the sample used to determine TML.
The sample used to determine TML should not be used to determine moisture.
Stationary sampling of stockpiles should never
...