ISO 8858-3:2004

SLOVENSKI STANDARD
01-november-2005
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Hard coal -- Froth flotation testing -- Part 3: Release evaluation
Houille -- Essais de flottation -- Partie 3: Évaluation des émissions
Ta slovenski standard je istoveten z: ISO 8858-3:2004
ICS:
73.040 Premogi Coals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 8858-3
First edition
2004-08-15
Hard coal — Froth flotation testing —
Part 3:
Release evaluation
Houille — Essais de flottation —
Partie 3: Évaluation des émissions

Reference number
©
ISO 2004
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©  ISO 2004
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ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 1
4 Principle. 1
5 Reagents. 1
6 Apparatus. 2
7 Sampling and preparation of test sample . 4
8 Flotation test conditions . 5
8.1 Test temperature. 5
8.2 Impeller operating speed. 5
8.3 Air flow rate . 5
8.4 Pulp level. 5
9 Procedure. 5
9.1 Test portion. 5
9.2 Preparation. 5
9.3 Flotation test. 5
10 Presentation of results . 6
11 Test report. 7
Bibliography . 9

Foreword
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(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
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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.
ISO 8858-3 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 1, Coal
preparation: Terminology and performance.
ISO 8858 consists of the following parts, under the general title Hard coal — Froth flotation testing:
 Part 1: Laboratory procedure
 Part 2: Sequential evaluation
 Part 3: Release evaluation
iv © ISO 2004 – All rights reserved

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 8858-1:1990 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 part of ISO 8858 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 part of ISO 8858 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.

INTERNATIONAL STANDARD ISO 8858-3:2004(E)

Hard coal — Froth flotation testing —
Part 3:
Release evaluation
1 Scope
This part of ISO 8858 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
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 1213-1:1993, Solid mineral fuels — Vocabulary — Part 1: Terms relating to coal preparation
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 8858-1:1990, Hard coal — Froth flotation testing — Part 1: Laboratory procedure
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1213-1 apply.
4 Principle
A test portion of coal is mixed with water to form a suspension in the flotation cell, or a test portion of slurry is
added to the cell and diluted. A collector and frother are added, the suspension is conditioned and air is then
introduced to the cell while agitation is maintained by means of an impeller.
To study differing flotation characteristics, the flotation operation is inhibited in two ways, relating to reagent
dosage rate in the first stage of the test and to air flow rate in the second stage.
A number of froth increments are obtained which give spaced points for comparison.
5 Reagents
Use only reagents of recognized analytical grade and the following.
5.1 Water, conforming to grade 3 of ISO 3696.
5.2 Collector, undiluted n-dodecane.
5.3 Frother.
Prepare a solution of 0,1 % (V/V) 4-methylpentan-2-ol (formerly called methyl isobutyl carbinol or MIBC) by
diluting 1 ml of MIBC to 1 litre using water (see 5.1). All dosages of MIBC stated refer to this solution.
6 Apparatus
6.1 Flotation machine
As described in 6.1 of ISO 8858-1:1990, consisting of a mechanical impeller-type flotation machine designed
for laboratory-scale flotation testing, comprising the following.
a) A flotation cell, of capacity approximately 3,5 litres, made from an inert material, such as stainless steel,
glass or polymethyl methacrylate.
b) An impeller assembly, capable of being driven so that the periphery of the impeller moves at a speed of
approximately 5,7 m/s. The impeller shall be positioned centrally with a clearance of no more than 5 mm
from the base of the cell.
c) A means of supplying air to the impeller.
A typical flotation machine is shown in Figures 1 and 2.
6.2 Air flowmeter, with a needle valve to control the air flow rate to the flotation cell.
6.3 Constant level device, for maintaining the pulp at a constant level during the test.
NOTE The level may be maintained by the manual addition of water.
6.4 Two scrapers, for removing the froth from the entire surface of the pulp, including the area behind the
standpipe.
6.5 Calibrated micro-syringe or micro-pipette.
6.6 Containers, capable of holding individual samples of froth and tailings.
6.7 Timing device, accurate to ± 1 s and capable of being zeroed and started as required.
2 © ISO 2004 – All rights reserved

Key
1 drive mechanism
2 cell
3 metal base
4 levelling screws
Figure 1 —Typical flotation machine
Key
1 cell
2 hood diffuser
3 impeller
4 impeller shaft
Figure 2 —Detail of flotation cell and impeller
7 Sampling and preparation of test sample
Take a gross sample which is at least five times the mass required for a single flotation test (see 9.1).
Where the sample for flotation testing is obtained in slurry form, allow it to settle for at least 12 h and then
remove the supernatant water. Mix the resulting thickened slurry and determine its solids content.
The history and method of preparation of the sample can affect the flotation characteristics of the coal. The
source of the sample should be recorded and care should be taken to ensure that samples for comparative
tests are prepared in the same manner. Since replicate tests are required together with subsampling for size
analysis and other tests, care should be taken in mixing and subdivision of the original sample. When
applicable, sampling and division of samples should be carried out in accordance with ISO 13909-2.
The use of chemical additives to enhance the settlement of a slurry and the use of heat to drive off water
should not be employed because such practices can affect the flotation characteristics of the coal.
4 © ISO 2004 – All rights reserved

8 Flotation test conditions
8.1 Test temperature
The test temperature shall be as specified in ISO 8858-1
...