ISO 8858-1:2019

INTERNATIONAL ISO
STANDARD 8858-1
Second edition
2019-06
Hard coal — Froth flotation testing —
Part 1:
Laboratory procedure
Houille — Essais de flottation —
Partie 1: Méthode de laboratoire
Reference number
©
ISO 2019
© ISO 2019
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ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 2
6 Apparatus . 2
7 Sampling . 3
8 Flotation conditions . 4
8.1 Operating temperature . 4
8.2 Water . 4
8.3 Solids content . 4
8.4 Pulp level . 4
8.5 Collector . 4
8.6 Frother . 4
8.7 Air flow rate . 4
9 Procedure. 4
10 Expression of results . 6
11 Test report . 6
Annex A (informative) Recommended layout of a form for a test report .13
Bibliography .14
Foreword
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different types of ISO documents should be noted. This document was drafted in accordance with the
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.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee
SC 1, Coal preparation: Terminology and performance.
This second edition cancels and replaces the first edition (ISO 8858-1:1990), of which it constitutes a
minor revision. It also incorporates the Technical Corrigendum ISO 8858-1:1990/Cor.1:2001.
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.
iv © ISO 2019 – All rights reserved

Introduction
The froth flotation of coal has widespread application for the concentration and separation of fine coal
particles from mineral matter. The response of coal to the froth flotation process is initially measured
by a laboratory scale test. Although the principles used for the laboratory tests are generally similar,
the precise type of equipment and techniques used vary considerably.
The procedure for the laboratory froth flotation test sets out, in detail, the type of equipment to be
used and the methods to be adopted. The purpose of this procedure is to provide a standard method of
test by which a preliminary evaluation of the froth flotation characteristics of a coal can be compared.
This need is particularly important for exploration programmes. This document also serves as an
introduction for operators who are not familiar with the techniques (and problems) associated with the
laboratory froth flotation of coals.
Annex A of this document is for information only.
INTERNATIONAL STANDARD ISO 8858-1:2019(E)
Hard coal — Froth flotation testing —
Part 1:
Laboratory procedure
1 Scope
This document sets out a laboratory procedure for the froth flotation testing of fine coal, e.g. coal of
particle size less than 0,5 mm. The procedure provides a means of evaluating the general flotation
characteristics of a coal under a set of specified standard conditions, and will not necessarily indicate
the full flotation potential of that coal.
The flotation characteristics of coals are sensitive to changes in flotation conditions. These conditions
can be changed by varying basic parameters such as flotation time, reagent and dosage rate. Separate
flotation tests are used to assess the effect of varying these parameters to determine the best flotation
conditions for a particular coal. A method of evaluating flotation response will be given in a separate
standard.
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 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes
of openings
ISO 648, Laboratory glassware — Single-volume pipettes
ISO 1171, Solid mineral fuels — Determination of ash
ISO 11722, Solid mineral fuels — Hard coal — Determination of moisture in the general analysis test
sample by drying in nitrogen
ISO 1213-1, Solid mineral fuels — Vocabulary — Part 1: Terms relating to coal preparation
ISO 13909-1, Hard coal and coke — Mechanical sampling — Part 1: General introduction
ISO 13909-2, Hard coal and coke — Mechanical sampling — Part 2: Coal — Sampling from moving streams
ISO 13909-3, Hard coal and coke — Mechanical sampling — Part 3: Coal — Sampling from stationary lots
ISO 13909-4, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples
ISO 18283, Hard coal and coke — Manual sampling
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1213-1 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
collector
collecting agent
reagent added to a pulp to bring about adhesion between solid particles and air bubbles
3.2
flotation concentrate
clean product recovered in froth flotation
3.3
conditioning
preparatory stage in the flotation process in which the reagents are brought into intimate contact with
the solids of the pulp
3.4
frother
frothing agent
reagent used to control the size and stability of the air bubbles in the flotation process
3.5
froth flotation
process for cleaning fine coal in which the coal, with the aid of a reagent or reagents, becomes attached
to air bubbles in a liquid medium and floats as a froth
3.6
pulp
mixture of solid particles and water
3.7
flotation tailings
reject from froth flotation cells
4 Principle
Mixing of a coal sample with water to form a suspension in the flotation cell. Addition of collector and
frother and introduction of air. Separate recovery of the concentrate and tailings and determination of
the yield and ash of each.
NOTE 1 The use of chemical additives or heat can affect the flotation characteristics of the coal.
5 Reagents
During the analysis, use only reagents of recognized analytical grade and only distilled water or water
of equivalent purity.
5.1 Collector, n-Dodecane.
5.2 Frother, Methyl iso-butyl carbinol (MIBC), (4-Methylpentan-2-ol), 0,14 % (V/V) aqueous solution.
6 Apparatus
The apparatus shall be a mechanical impeller type flotation machine (see Figure 1) with the following
specifications.
2 © ISO 2019 – All rights reserved

6.1 Flotation cell manufactured from stainless steel.
Figure 2 shows the dimensions of the flotation cell. The capacity of the cell with the deflector block and
impeller in place is approximately 3,5 l.
It has been shown that the results obtained from laboratory froth flotation tests are very dependent
on the procedure used to remove the concentrate from the surface of the pulp. For this reason, a
deflector block manufactured from plastics material (see Figure 3) is used to guide the concentrate to
a rectangular area in front of the impeller housing. The concentrate can then be removed by means of a
scraper (see Figure 4) which is designed to cover the full width of the cell to a constant depth.
In order to establish the volume of pulp which can be contained in the flotation cell, the deflector
block is fitted into the cell and water is added to the flotation cell to about 20 mm to 30 mm below the
required pulp level. The impeller is started (air valve off) and additional water is added to the required
mark (see 8.4). The impeller is stopped, the deflector block removed, and
...