ISO 10251:2006

Copper, lead, zinc and nickel concentrates - Determination of mass loss of bulk material on drying

ISO 10251:2006 specifies methods for the determination of moisture content of a lot of copper, lead, zinc or nickel concentrate, defined as the percentage mass loss of the moisture test portion under the conditions of drying specified in this document. ISO 10251:2006 is not applicable to drying samples used for determination of volatile elements such as mercury and sulfur.

Concentrés de cuivre, de plomb, de zinc et de nickel — Détermination de la perte de masse au séchage du matériau en vrac

General Information

• Status: Published
• Publication Date: 26-Apr-2006
• ICS: 73.060.99 - Other metalliferous minerals
• Technical Committee: ISO/TC 183 - Copper, lead, zinc and nickel ores and concentrates
• Drafting Committee: ISO/TC 183/WG 9 - Sampling of copper, lead and zinc concentrates
• Current Stage: 9092 - International Standard to be revised
• Start Date: 23-May-2025
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 6246:2017 - Petroleum products - Gum content of fuels - Jet evaporation method
• Effective Date: 06-Jun-2022
• Revises: ISO 10251:1997 - Copper, lead and zinc sulfide concentrates - Determination of mass loss of bulk material on drying
• Effective Date: 15-Apr-2008

Overview

ISO 10251:2006 specifies standardized laboratory methods for determining the moisture content of copper, lead, zinc and nickel concentrates. Moisture is defined as the percentage mass loss of a test portion when dried under the conditions given in the standard. The document sets requirements for sampling, drying, weighing and calculation of moisture content, and provides procedures when concentrates are susceptible to oxidation, decomposition or sublimation. Note: ISO 10251:2006 is not applicable to drying samples intended for determination of volatile elements such as mercury or sulfur.

Key topics and technical requirements

• Drying conditions: Test portions are dried at 105 °C ± 5 °C (forced-air oven or inert-gas circulation) and dried to constant mass where possible.
• Test portion size: Minimum 1 kg per test portion; trays should allow sample spread to a thickness < 30 mm.
• Weighing precision: Top-loading balance with minimum precision about 0.01 % (per Table 1).
• Drying cycles: An initial drying period (16 h suggested for many concentrates) followed by repeated 4 h cycles until two successive mass readings agree within 0.05 % of the initial test portion mass.
• Special handling methods (Methods 1–5): Guidance on choosing drying approach when concentrates:
  • can be dried to constant mass,
  • are susceptible to oxidation (use inert atmosphere or common sample),
  • lose organics during prolonged drying,
  • cannot reach constant mass (interrupt drying after a specified period),
  • gain mass after drying (oxidation risk).
• Annexes:
  • Annex A - test for susceptibility to oxidation, decomposition and sublimation
  • Annex B - handling cohesive or very wet concentrates (predrying)
  • Annex C - example worksheet for results
• Sampling linkage: Moisture sampling and processing must follow ISO 12743 to ensure representativeness.

Practical applications and users

• Used by mining companies, metallurgical labs, assay houses, quality control teams, and commodity traders to:
  • determine moisture for mass and value calculations,
  • prepare samples for accurate chemical analysis,
  • establish saleable dry-mass or adjust freight and processing charges.
• Practical value: ensures consistent, reproducible moisture determination across laboratories and supports unbiased metal content estimates when preparing predried or hygroscopic samples.

Related standards

• ISO 12743 - Sampling procedures for concentrates (referenced for sampling and representativeness)
• ISO 9599 - Hygroscopic moisture determination (used for volatile element analyses and ambient drying)

Keywords: ISO 10251:2006, moisture content, copper concentrate, drying to constant mass, sample drying, oxidation, inert atmosphere, concentrate moisture determination.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 10251
Second edition
2006-05-01
Copper, lead, zinc and nickel
concentrates — Determination of mass
loss of bulk material on drying
Concentrés de cuivre, de plomb, de zinc et de nickel — Détermination
de la perte de masse au séchage du matériau en vrac

Reference number
©
ISO 2006
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ii ISO 2006 – All rights reserved

Contents Page
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Drying method . 2
5 Apparatus . 4
6 Processing of samples . 4
7 Moisture samples . 4
8 Procedure for drying samples to constant mass . 5
9 Calculation . 6
10 Test report . 9
Annex A (normative) Test for susceptibility of concentrates to oxidation, decomposition and
sublimation . 10
Annex B (normative) Determination of moisture content of cohesive or wet concentrates . 11
Annex C (informative) Example of a work sheet for the determination of moisture content
of each test portion in accordance with this International Standard . 12
Bibliography . 13
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ISO 2006 – All rights reserved iii

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.
ISO10251 was prepared by Technical Committee ISO/TC183, Copper, lead, zinc and nickel ores and
concentrates.
This second edition cancels and replaces the first edition (ISO 10251:1997), which has been technically
revised.
©
iv ISO 2006 – All rights reserved

Introduction
Reference to the percentage mass loss as moisture content is appropriate because, although oxidation,
decomposition or sublimation of elemental sulfur may contribute, most of the mass loss on drying is due to loss
of moisture.
When oxidation, decomposition or sublimation of elemental sulfur has been shown to occur or volatile organic
flotation reagents such as kerosene are present, the chemical analysis test sample should be prepared from the
dried moisture test portions. Under these circumstances, the sampling scheme established in accordance with
ISO 12743 must ensure that moisture samples and test portions are sufficiently representative for subsequent
chemical analysis. Where oxidation is a problem, an inert atmosphere may also be used during the drying
stage. Annex A provides a procedure by which it can be determined whether or not a concentrate is susceptible
to oxidation, decomposition or sublimation.
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ISO 2006 – All rights reserved v

.
vi
INTERNATIONAL STANDARD ISO 10251:2006(E)
Copper, lead, zinc and nickel concentrates — Determination of
mass loss of bulk material on drying
WARNING — This International Standard may involve hazardous materials, 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 to establish appropriate health and safety practices and determine the
applicability of regulatory limitations prior to use.
1Scope
This International Standard specifies methods for the determination of moisture content of a lot of copper, lead,
zinc or nickel concentrate, defined as the percentage mass loss of the moisture test portion under the
conditions of drying specified in this document.
In order to obtain an unbiased estimate of the metal content of the lot, it is important that the same drying
conditions are used for the determination of bulk and hygroscopic moisture or for preparing a predried test
portion.
This International Standard is not applicable to drying samples used for determination of volatile elements such
as mercury and sulfur. Such samples are allowed to dry at ambient temperature, and a hygroscopic moisture
determination is carried out according to ISO 9599 at the time of chemical analysis.
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 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.
3.1
representative sample
quantity of concentrate representing a larger mass of concentrate with both precision and bias within
acceptable limits
3.2
lot
quantity of concentrate to be sampled
3.3
lot sample
quantity of concentrate that is representative of the lot
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ISO 2006 – All rights reserved 1

3.4
sub-lot
subdivided parts of a lot that are processed separately, each of them producing a subsample which is analysed
separately, e.g. for moisture determination
3.5
subsample
quantity of concentrate that is representative of the sub-lot
3.6
increment
quantity of concentrate selected by a sampling device in one operation
3.7
moisture sample
representative quantity of concentrate from which test portions are taken for moisture determination
NOTE Alternatively, the whole moisture sample may be dried to determine its moisture content.
3.8
laboratory sample
sample that is processed so that it can be sent to the laboratory and used for further processing and selection
of one or more test samples for chemical analysis
3.9
common sample
representative quantity of concentrate that is dried to determine its mass loss and subsequently used for further
processing and selection of one or more test samples for chemical analysis
3.10
test sample
representative quantity of concentrate obtained for a laboratory sample when additional preparation, such as
drying or hygroscopic moisture determination, is needed prior to selection of one or more test portions
3.11
test portion
representative quantity of concentrate taken from a moisture sample, a laboratory sample or a test sample that
is submitted to moisture determination or analysis in its entirety
4 Drying method
4.1 General
◦ ◦
Test portions are dried at 105 C± 5 C until constant mass is obtained and the moisture content determined
as the percentage mass loss on drying. However, drying to constant mass can be difficult or impossible if the
concentrate is susceptible to oxidation, decomposition or sublimation of elemental sulfur, or volatile organic
flotation reagents such as kerosene are present (see Annex A). Under these circumstances, using a common
sample for moisture determination and chemical analysis, drying in an inert atmosphere, or interrupting the
drying is applied. Of these alternatives, the use of a common sample is the best approach, although care needs
to be taken to ensure that the moisture samples and test portions are sufficiently representative for subsequent
chemical analysis.
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2 ISO 2006 – All rights reserved

One of the following drying methods is selected to suit the particular concentrate. A flow chart for selecting the
correct drying method is given in Figure 1, noting that use of a common sample is applicable in all cases.
Figure 1 — Procedure for selection of appropriate drying method
4.2 Method 1
Where the test portion can be dried to constant mass and the concentrate passes the test in Annex A, a
separate sample for moisture determination or a common sample is dried to constant mass.
4.3 Method 2
Where the test portion can be dried to constant mass but the test in Annex A results in a higher mass (indicating
that the concentrate is susceptible to oxidation) moisture and chemical analysis samples are dried to constant
mass in an inert atmosphere, or a common sample is dried to constant mass.
4.4 Method 3
Where the test portion can be dried to constant mass but the test in Annex A results in a lower mass (indicating
that the concentrate may be losing organics over an extended period) a common sample is dried to constant
mass.
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ISO 2006 – All rights reserved 3

4.5 Method 4
Where the test portion cannot be dried to constant mass and continues to lose mass over long periods
(indicating that the concentrate may be losing hydrated water, decomposing or subliming) a common sample is
used, with interruption of drying after a period determined in accordance with Clause 8 for each concentrate
type, and no further drying prior to analysis.
4.6 Method 5
Where the test portion cannot be dried to constant mass and after the initial drying period continues to gain
mass (indicating that
...