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 12742:2020(E)
©
ISO 2020

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ISO 12742:2020(E)

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© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ISO 12742:2020(E)

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
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ISO 12742:2020(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
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.
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
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
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 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.
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ISO 12742:2020(E)

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.
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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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ISO 12742:2020(E)

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.
5 Apparatus
Copper, lead and zinc concentrates can 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.
1)
5.1 Flow table and frame , as specified in Annex A.
The flow-table mounting shall be as specified in Figure A.1.
1)
5.2 Mould , as specified in Figure A.1.
1)
5.3 Tamper .
The required tamping pressure can 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.
5.4 Calliper ruler.
5.5 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
5.6 Measuring cylinder, of capacity 50 ml to 200 ml.
5.7 Burette, of capacity 10 ml.
1) Material from the IMO publication ‘IMSBC Code, 2020 Edition’ (sales code: IJ260E), is reproduced with the
permission of the International Maritime Organization (IMO), which does not accept responsibility for the
correctness of the material as reproduced; in case of doubt, IMO's authentic text shall prevail. Readers should check
with their national maritime administration for any further amendments or latest advice. International Maritime
Organization, 4 Albert Embankment, London, SE1 7SR, United Kingdom.
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ISO 12742:2020(E)

2)
5.8 Mixing bowl , hemispherical, of diameter approximately 30 cm.
It is recommended that an automatic mechanical mixer having a mixing bowl as described is used, as
this leads to improved precision.
5.9 Rubber gloves.
5.10 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.
5.11 Drying oven, ventilated, with forced circulation of air or inert gas, regulated at a temperature of
105 °C ± 5 °C.
5.12 Airtight containers.
6 Sampling and sample preparation
6.1 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.
To ensure that the TML result is representative, increments of the material shall be taken in accordance
with ISO 12743, 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 content.
Stationary sampling of stockpiles should never be used for the determination of TML. This method
of sampling can only be used to provide an indicative moisture value for use during the planning of
shipping schedules.
6.2 Laboratory sample
Samples for the determination of TML shall be taken in accordance with ISO 12743. The laboratory
sample shall not weigh less than 12 kg. To minimize changes to the flow characteristics of the sample, it
shall not be oven-dried or ground during its preparation, although partial drying as described in 7.4.4
is allowed.
2) Material from the IMO publication ‘IMSBC Code, 2020 Edition’ (sales code: IJ260E), is reproduced with the
permission of the International Maritime Organization (IMO), which does not accept responsibility for the
correctness of the material as reproduced; in case of doubt, IMO's authentic text shall prevail. Readers should check
with their national maritime administration for any further amendments or latest advice. International Maritime
Organization, 4 Albert Embankment, London, SE1 7SR, United Kingdom.
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ISO 12742:2020(E)

6.3 Sample preparation
Homogenize the laboratory sample as quickly as possible to prevent moisture losses. Take nine test
samples as follows:
a) Sample 1
Take not less than 2 kg from the laboratory sample. This sample is to be used for determining the
moisture content of the sample as received. Place this sample on a drying tray or pan.
b) Sample 2
Take approximately 1,2 kg from the laboratory sample. This sample is to be used for the preliminary
TML test. Store this sample in an appropriately labelled airtight container.
c) Samples 3 to 6
Take four samples of approximately 1,2 kg from the laboratory sample. These samples are to be
used for the main TML test. Store these samples in appropriately labelled airtight containers.
d) Samples 7 to 9
Take three samples of approximately 1,2 kg from the laboratory sample. These samples are to
be used for confirmation of TML by the graphical method. Store these samples in appropriately
labelled airtight containers.
7 Procedure
7.1 General
Copper, lead and zinc concentrates can undergo rapid changes in moisture when exposed to air, so all
stages of the test should be accomplished in the shortest time period and shall be completed within the
day of commencement. Where possible, sample containers should be covered with plastic film or any
other suitable airtight cover.
The moisture result from sample 1 provides information about how far the material under test is from
the flow moisture point.
As more accurate results are obtained when the moisture of the test portion is close to the flow
moisture point, a preliminary test is carried out (sample 2). The result of this test is used to adjust the
moisture of the final test portion to 1 % to 2 % relative below (samples 3 and 4) and above (samples 5
and 6) the flow moisture point.
To check the main flow moisture point graphically, three more samples (samples 7 to 9), having moisture
values higher than the flow moisture point, are tested. The flow moisture point is the extrapolation to
zero of the least squares linear regression of the test portions showing a measurable displacement. The
value obtained this way will be used to validate the main flow moisture point.
3)
7.2 Preparation of test portions
7.2.1 General
Sample 1 shall be prepared in accordance with ISO 10251. Proceed to 7.7.
3) Material from the IMO publication ‘IMSBC Code, 2020 Edition’ (sales code: IJ260E), is reproduced with the
permission of the International Maritime Organization (IMO), which does not accept responsibility for the
correctness of the material as reproduced; in case of doubt, IMO's authentic text shall prevail. Readers should check
with their national maritime administration for any further amendments or latest advice. International Maritime
Organization, 4 Albert Embankment, London, SE1 7SR, United Kingdom.
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ISO 12742:2020(E)

Samples 2 to 9 shall be prepared in accordance with 7.2.2 to 7.2.6.
7.2.2 Filling the mould
Place the mould on the centre of the flow table and fill it in three stages with the test portion as follows:
a) the first charge, after tamping, shall aim to fill the mould to approximately one-third of its depth;
b) the second charge, after tamping, shall fill the mould to about two-thirds of its depth;
c) the third and final charge, after tamping, shall reach to just below the top of the mould (see
Figure 1).
The quantity of test portion required to achieve each of these stages will vary from one material to
another, but is readily established after experience has been gained on the packing characteristics of
the material being tested.
7.2.3 Tamping pressure
The aim of tamping is to simulate the amount of compaction prevailing at the bottom of a shipboard
cargo for the material being tested. The correct pressure to be applied via the tamper is calculated
using Formula (1).
pd=×ρ ×g (1)
TD max
where
p is the tamping pressure, in pascals;
T
ρ is the bulk density, in kilograms per cubic metre;
D
d is the maximum depth of the cargo, in metres;
max
2
g is the acceleration due to gravity (= 9,81 m/s ).
If, when calculating the tamping pressure, there is no information available concerning the cargo depth,
use the maximum likely depth.
Alternatively, the pressure can be estimated from Table 2.
a
Table 2 — Tamping pressures for selected concentrates
Typical Bulk density
Tamping pressure at maximum cargo depth
3
concentrate kg/m
kPa
type
 2 m 5 m 10 m 20 m
Copper 2 000 39 [2,8] 98 [6,9] 196 [13,9] 392 [27,7]
Lead 2 100 41 [2,9] 103 [7,3] 206 [14,6] 412 [29,1]
Zinc 1 950 38 [2,7] 96 [6,8] 192 [13,5] 384 [27,1]
a
Values in square brackets are the equivalent kilogram-force (kgf) when applied via a 30 mm-diameter tamper head.
[1]
Appendix 2 in the ISMBC code nominates suitable methods that can be used to determine a value for
bulk density for use in the calculation of tamping pressure using Formula (1).
7.2.4 Tamping procedure
The number of tamping actions (applying the correct, steady pressure each time) should be 35 for the
bottom layer, 25 for the middle layer and 20 for the top layer. Tamping shall be performed successively
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ISO 12742:2020(E)

over the complete area, including the edges of the sample, to form a uniform surface for each layer (see
Figure 1).
7.2.5 Removal of the mould
Tap the mould on its side until it becomes loose, leaving the material in the shape of a truncated cone on
the flow table. Clean the surface of the table around the cone. Measure the size of the cone in the four
directions marked on the table. The average of these readings will be equivalent to zero displacement.
7.2.6 Dropping the flow table
Immediately after removing the mould, raise and drop the flow table 50 times through a height of
12,5 mm ± 0,13 mm at a rate of 25 times per minute. While the flow table is going through these cycles,
observe the behaviour of the material using the information provided in 7.3 as a guide for determining
the flow state.
7.3 Identification of the flow state
The impacting action of the flow table causes the grains of the material to rearrange themselves to
produce compaction of the mass. As a result, the fixed volume of moisture contained in the material at
any given level increases as a percentage of the total volume. A flow state is considered to have been
reached when the moisture content and compaction of the material produce such a level of saturation
that plastic deformation occurs. At this stage, the moulded sides of the cone can deform, giving a convex
or concave profile (see Figure 2). With repeated action of the flow table, the cone continues to slump
and to flow outwards. In certain materials, cracks can also develop on the top surface (see Figure 3).
Figure 1 — Example of third stage of filling the mould
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ISO 12742:2020(E)

Figure 2 — Example of the material at the flow point (left) and at the flow point showing a
moisture trail on the flow table (right)
Figure 3 — Example of material crumbling but not at the flow point
Any increase in diameter at the base or anywhere along the side of the cone indicates plastic flow and
thus that the material has reached the flow point. However, in certain circumstances the diameter of
the cone can increase before the flow moisture point is reached, due to friction between the grains
rather than plastic flow. Refer to the following further criteria to differentiate this type of deformation
from a flow moisture state.
Further criteria to use when determining if the flow state has been reached are as follows (see Figure 4).
a) Cracking with the appearance of free moisture is not an indication of development of a flow state.
In most cases, measurement of the deformation is helpful in deciding whether or not plastic flow
has occurred. A template that, for example, will indicate an increase in diameter of up to 3 mm in
any part of the cone is a useful guide for this purpose.
b) When the moisture content is approaching the flow moisture point (FMP), the cone begins to show
a tendency to stick to the mould.
c) When the cone is pushed off the table, it can leave tracks (stripes) of moisture on the table. If such
stripes are seen, the moisture content can be above the flow moisture point. Slight deformation of
the cone can appear at moisture contents lower than the flow moisture point, but in that case the
test portion will leave no moisture tracks when removed.
d) Measuring the diameter of the cone, at the base or at half height, will always be useful. By addition
of water in increments of 0,2 % to 0,3 % by mass and applying 50 drops of the flow table, the first
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ISO 12742:2020(E)

diameter increase will generally be between 1 mm and 5 mm. Water addition at this point shall
be minimised to achieve a diameter increase at the lower end of the 1 mm to 5 mm range (ideally
between 1 mm and 3 mm). Displacement of greater than 5 mm indicates that the flow point has
been well exceeded.
Key
FMP flow moisture point
Figure 4 — Identification of the flow state
4)
7.4 Preliminary flow moisture point
7.4.1 Preparation of test portion
Prepare test portion 2 for determining the preliminary flow moisture point in accordance with 7.2.2
to 7.2.6.
7.4.2 Determination of preliminary flow moisture point
If the material exhibits any of the properties described in 7.3, then the flow moisture point has been
reached. After the table has stopped, immediately measure the displacement of the test portion with a
calliper ruler in the four directions marked on the table. Split the cone into two halves and place each
half in a pre-weighed drying tray or pan. Immediately weigh the test portion and tray and determine
the moisture content as described in 7.7, irrespective of the mass requirements of ISO 10251.
If the material does not exhibit any of the properties described in 7.3, or simply crumbles and bumps
off in fragments with successive drops of the table (see Figure 3), the flow moisture point has not been
reached and more water needs to be added to the sample, as described in 7.4.3.
4) Material from the IMO publication ‘IMSBC Code, 2020 Edition’ (sales code: IJ260E), is reproduced with the
permission of the International Maritime Organization (IMO), which does n
...