ISO 9033:2026

International
Standard
ISO 9033
Second edition
Aluminium ores — Determination
2026-11
of the moisture content of bulk
material
Minerais alumineux — Détermination de l'humidité du matériau
en vrac
Reference number
© ISO 2026
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 1
6 Sampling and samples . . 1
7 Procedure . 2
7.1 Test portion .2
7.2 Number of determinations .2
7.3 Drying of test portion .2
8 Expression of results . 3
8.1 Moisture content of test portion .3
8.2 Moisture content of consignment .3
8.2.1 Moisture samples from each increment or subsample analysed separately .3
8.2.2 Moisture samples combined to from a gross sample.4
8.3 Correction for rainfall and sprayed water .4
8.4 Calculation of final result .4
9 Test report . 4
Annex A (informative) Determination of moisture content of adhesive or wet aluminium ore . 5
Annex B (normative) Correction either sprayed water or rainfall, or both . 7

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 79, Light metals and their alloys, Subcommittee
SC 12, Aluminium ores.
This second edition cancels and replaces the first edition (ISO 9033:1989), which has been technically
revised.
The main changes are as follows:
— the maximum allowable difference between subsequent weighings of dried samples and accuracy of
weighing in Table 1 has been modified;
— a requirement on dried ore has been added to Clause A.2.
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
Introduction
Aluminum ores are an important raw material for alumina production and their annual consumption is very
large. Moisture content is an important parameter in commercial transactions of aluminum ores, so it is
necessary to formulate a method to determine the moisture content of bulk material in aluminum ores in
order to reduce disputes in the trade of aluminum ores.
Annex A specifies a method to be used when it is difficult to carry out sieving, crushing and dividing owing
to the sample being adhesive or excessively wet. In this case, the sample may be pre-dried until preparation
can be conducted without any trouble. The pre-dried moisture content of a consignment can be determined
by the procedure specified in Annex A.
Annex B specifies methods of correction either sprayed water or rainfall or both. In the event of the
consignment being subjected to either sprayed water or rainfall or both to control dust emission, the
moisture content of the consignment can be corrected for this added water in accordance with Annex B.

v
International Standard ISO 9033:2026(en)
Aluminium ores — Determination of the moisture content of
bulk material
1 Scope
This document specifies a method to determine the moisture content of aluminium ores. It applies to the
samples taken from bulk aluminium ores, e.g. shipments and stockpiles.
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 8685, Aluminium ores — Sampling procedures
ISO 6140, Aluminium ores — Preparation of samples
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
The test portion is dried to a constant mass in a ventilated oven with forced circulation of air regulated at
105 °C ± 5 °C. The loss in mass is then measured.
5 Apparatus
The usual laboratory apparatus and, in particular, the following shall be used.
5.1 Drying pan.
5.2 Ventilated oven, with forced circulation of air regulated at 105 °C ± 5 °C.
5.3 Weighing device, capable of being read to an accuracy of 0,05 % of the mass of the test portion.
6 Sampling and samples
Test samples shall be taken and prepared in accordance with the procedures specified in ISO 8685 and
ISO 6140 respectively. Two possibilities exist for the preparation of the moisture samples. These are:
a) The moisture samples prepared from each increment or subsample are prepared and analysed
individually.
b) The moisture samples from each increment or subsample are combined to form a gross sample.
7 Procedure
7.1 Test portion
The test portions prepared by the procedure specified in ISO 6140 shall be provided in sealed containers
and shall have the minimum masses specified in Table 1.
The moisture content of adhesive or wet aluminium ore can be determined by the procedure specified in
Annex A.
When a test portion is too large for the ventilated oven (5.2) , it may be divided into several parts for drying.
Divide the portion into the minimum number of parts possible, taking care to avoid a change in moisture
content. In no case shall the minimum mass of a part be less than 1 kg.
Alternatively, to avoid dividing large test portions into parts for drying, moisture determinations may be
carried out on individual increments or subsamples as taken, provided the sum of the masses of all the
increments or subsamples exceeds the mass of the test portions given in Table 1.
7.2 Number of determinations
Moisture determination may be carried out in one of the following ways:
a) Where moisture samples from individual increments or subsamples are analysed separately, one
moisture determination shall be carried out on each subsample. If there are fewer than four subsamples
per consignment, duplicate test portions shall be prepared from each subsample and analysed.
b) Where the moisture samples from each subsample are combined to form a gross moisture sample, four
test portions shall be prepared. Moisture determinations shall be carried out on two of the test portions
with the remaining two test portions kept in reserve.
7.3 Drying of test portion
Weigh the container and aluminium ore test portion before opening the container (as received). Weigh the
clean, dry drying pan (5.1). Transfer the aluminium ore to the drying pan and spread the ore evenly to a
depth not exceeding that specified in Table 1.
Place the dry
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