ISO/PRF 9033

• Abstract:

  Applies to the samples taken from bulk aluminium 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. Annex B specifies methods of correction for sprayd water and/or rainfall.

• Status: Not Published
• ICS: 73.060.40 - Aluminium ores
• Technical Committee: ISO/TC 79/SC 12 - Aluminium ores
• Drafting Committee: ISO/TC 79/SC 12 - Aluminium ores
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 09-Sep-2026
• Completion Date: 12-Sep-2026

• Revises: ISO 9033:1989 - Aluminium ores — Determination of the moisture content of bulk material
• Effective Date: 19-Oct-2024

Overview

ISO/PRF 9033: Aluminium Ores - Determination of the Moisture Content of Bulk Material is an international standard developed by ISO Technical Committee 79/SC 12. This standard provides a comprehensive method for sample-based determination of moisture content in bulk aluminium ores. Accurate measurement of moisture content is essential for commercial transactions, quality control, and dispute resolution related to aluminium ore shipments and stockpiles.

The document addresses typical scenarios encountered in the aluminium ore industry, including challenges posed by excessively wet or adhesive samples and the practical need to correct for moisture changes introduced by spray water or rainfall during ore handling.

Key Topics

• Scope: The standard applies to samples taken from bulk aluminium ores, including those from shipments and storage piles.
• Moisture Determination: Specifies procedures for drying and weighing test portions to calculate accurate moisture percentages.
• Sample Preparation: Offers guidance on the preparation and handling of samples according to referenced ISO standards.
• Handling Wet or Adhesive Ores: Annex A details procedures for pre-drying difficult samples, ensuring reliable results even with challenging materials.
• Corrections for Spray Water and Rainfall: Annex B outlines formulas and procedures to adjust moisture content for water introduced during dust control or by rainfall, ensuring accurate reporting regardless of handling conditions.
• Expression of Results: Requires results to be computed, rounded, and reported in a standardized manner to promote transparency in reporting.

Applications

ISO/PRF 9033 is highly relevant to organizations involved in mining, shipping, trading, and processing of aluminium ores. Key practical applications include:

• Commercial Transactions: Helps buyers, sellers, and traders determine equitable pricing based on standardized measurement of moisture content, reducing disputes.
• Shipping and Logistics: Enables shipping companies and port operators to assess cargo mass and value accurately after corrections for environmental factors.
• Quality Control: Assists laboratories and ore handling facilities in establishing traceable, repeatable procedures for determining and documenting the moisture content of ore consignments.
• Regulatory Compliance: Supports adherence to local and international regulations that mandate transparency and accuracy in the reporting of bulk material composition.
• Safety and Processing Optimization: Accurate moisture content measurement informs safe handling, storage, and effective processing in both alumina production and downstream metallurgical operations.

Industries benefit from the standard's clear methodology, including the specific guidance on overcoming sample preparation challenges and correction for water introduced during handling.

Related Standards

Several related ISO standards complement and support the implementation of ISO/PRF 9033:

• ISO 8685: Aluminium ores - Sampling procedures. Establishes methods for taking representative samples from bulk ores.
• ISO 6140: Aluminium ores - Preparation of samples. Outlines detailed procedures for preparing ore samples suitable for analysis.
• ISO/IEC Directives: Governs the standardization process, ensuring ISO/PRF 9033 adheres to international best practices.

These related documents help ensure consistency, reliability, and compatibility across procedures for sampling, preparation, and analysis in the aluminium ore industry.

---

By adopting ISO/PRF 9033:2026, organizations can improve their processes related to aluminium ore moisture analysis, fostering trust and efficiency across the global supply chain while complying with internationally recognized best practices for material testing and reporting.

International
Standard
ISO 9033
Second edition
Aluminium ores — Determination
of the moisture content of bulk
material
Minerais alumineux — Détermination de l'humidité du matériau
en vrac
PROOF/ÉPREUVE
Reference number
ISO 9033:2026(en) © ISO 2026
ISO 9033:2026(en)
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
ISO 9033:2026(en)
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 . . 2
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
PROOF/ÉPREUVE
iii
ISO 9033:2026(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at www.iso.org/
patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 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.
PROOF/ÉPREUVE
iv
ISO 9033:2026(en)
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.
PROOF/ÉPREUVE
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 6140, Aluminium ores — Preparation of samples
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 0,01 % of the mass of the test portion.
PROOF/ÉPREUVE
ISO 9033:2026(en)
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 drying pan with the ore together with the container and lid (if any) plus any adhering particles of
ore in the ventilated oven (5.2) and maint
...

Formatted: Spanish (Uruguay)
ISO/DISPRF 9033
Formatted: Spanish (Uruguay)
ISO/TC 79/SC 12
Secretariat: SAC
Date: 2026-06-1209-09
Aluminium ores — Determination of the moisture content of bulk
material
Minerais alumineux — Détermination de l'humidité du matériau en vrac
DIS stage
PROOF
VVototiinngg b beeggiinnss on on:: 22002255--0088--2211
VVootintingg te termrmiinnaatetess o onn:: 2 2002255--1111--1133

ISO/DISPRF 9033:2026(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Formatted: French (Switzerland)
E-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO/DISPRF 9033:2026(en)
Contents
Foreword . iii
Introduction . iii
Scope . iii
Normative references . iii
Terms and definitions . iii
Principle. iii
Apparatus . iii
Sampling and samples . iii
Procedure . iii
Test portion . iii
Number of determinations . iii
Drying of test portion . iii
Expression of results . iii
Moisture content of test portion . iii
Moisture content of consignment . iii
Correction for rainfall and sprayed water . iii
Calculation of final result . iii
Test report . iii
(Normative: The test method shall be carried out as specified in Annex A.) Determination of
moisture content of adhesive or wet aluminium ore. iii
(normative) Correction either sprayed water or rainfall, or both . iii
Foreword . v
Introduction . vi
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
8.3 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 . 6
iii
ISO/DISPRF 9033:2026(en)
Annex B (normative) Correction either sprayed water or rainfall, or both . 8

iv
ISO/DISPRF 9033:2026(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 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.;
— Addition of Aa requirement ofon dried ore inhas 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.
v
ISO/DISPRF 9033:2026(en)
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 AAnnex 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 and the. 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, then the moisture content of the consignment can be corrected for
this added water in accordance with  Annex B .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.
vi
ISO/DISPRF 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 6140, Aluminium ores — Preparation of samples
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/obphttps://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/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.,01 % of the mass of the test portion.
Formatted: Font: 11 pt, Not Bold
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:
ISO/DISPRF 9033:2026(en)
a) theThe moisture samples prepared from each increment or subsample are prepared and analysed
individually;.
b) theThe 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 (5.25.2) , 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 anal
...