National foreword

This British Standard is the UK implementation of ISO 8858‑3:2025. It supersedes BS ISO 8858‑3:2004, which is withdrawn.

The UK participation in its preparation was entrusted to Technical Committee W/-, Miscellaneous Standards.

A list of organizations represented on this committee can be obtained on request to its committee manager.

Contractual and legal considerations

This publication has been prepared in good faith, however no representation, warranty, assurance or undertaking (express or implied) is or will be made, and no responsibility or liability is or will be accepted by BSI in relation to the adequacy, accuracy, completeness or reasonableness of this publication. All and any such responsibility and liability is expressly disclaimed to the full extent permitted by the law.

This publication is provided as is, and is to be used at the recipient’s own risk.

The recipient is advised to consider seeking professional guidance with respect to its use of this publication.

This publication is not intended to constitute a contract. Users are responsible for its correct application.

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2025.

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 27, Coal and coke, Subcommittee SC 1, Coal preparation: Terminology and performance.

This second edition cancels and replaces the first edition (ISO 8858-3:2004), which has been technically revised.

The main changes are as follows:

the title has been updated;
ISO 13909‑2, ISO 13909‑4 and ISO 20904 were included as normative references.

A list of all parts in the ISO 8858 series can be found on the ISO website.

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.

Introduction

The froth flotation of coal has widespread application for the recovery of fine coal particles and their separation from unwanted mineral matter. The response of coal to the froth flotation process is measured initially by a laboratory scale test. ISO 8858‑1 provides a means of evaluating the general flotation characteristics of a coal under a set of specified conditions and will not necessarily indicate the full potential of that coal. It is accepted that variation of the many parameters in the froth flotation process can be used to effect the beneficiation of the product. This document describes methods of applying certain test conditions to reveal the relative response of coals to the flotation process.

To facilitate the determination of how a particular coal will respond to froth flotation, a method of controlling the recovery of froth is used. This is done by inhibiting the process to a degree, determining the rate at which coal reacts and by progressively sampling the froth. This method provides a basis to vary test parameters to explore any special flotation characteristics.

This document is applicable to a wide range of coals and provides a method of comparison of flotation behaviour and will facilitate the exchange of information relating to specific performance. It is expected that the use of this method will provide a tool for comparison of flotation characteristics.

From the results of the standard test, it is possible to draw evaluation curves similar to those obtained from the float and sinking of coal.

Because of the high reproducibility of results, the test represents a reliable means of comparing the flotation response of different samples.

1 Scope

This document describes a laboratory method for release evaluation of the froth flotation characteristics of hard coal, of particle size less than 0,5 mm. It is applicable to coal in powder form or in the form of a slurry.

2 Normative references

3 Terms and definitions

4 Principle

5 Reagents

5.1

5.2

5.3 Frother.

6 Apparatus

6.1 Flotation machine

6.2

6.3

6.4

6.5 Calibrated micro syringe or micro-pipette.

6.6

6.7

7 Sampling and preparation of test sample

8 Flotation test conditions

8.1 Test temperature

8.2 Impeller operating speed

8.3 Air flow rate

8.4 Pulp level

9 Procedure

9.1 Test portion

9.2 Preparation

9.3 Flotation test

10 Presentation of results

11 Test report

BS ISO 8858-3:2025

Coal — Froth flotation testing - Release evaluation

Current

Published:

30 Nov 2025