ISO 4701:2019

INTERNATIONAL ISO
STANDARD 4701
Fifth edition
2019-04
Iron ores and direct reduced iron —
Determination of size distribution by
sieving
Minerais de fer et minerais de fer préréduits — Détermination de la
granulométrie par tamisage
Reference number
©
ISO 2019
© ISO 2019
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ii © ISO 2019 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principles and planning . 2
4.1 General . 2
4.2 Purpose of the analysis . 2
4.3 Impact of ore and DRI properties . 2
4.3.1 Effect of moisture content. 2
4.3.2 Degradation of material . 3
4.3.3 Magnetic ores . 3
4.4 Nature of sample . 4
4.5 Choice of sieving method . 4
4.6 Maximum particle size permitted on a sieve . 4
4.7 Specified loading of sieves . 5
4.7.1 General. 5
4.7.2 Batch sieving with a single sieve or nest of sieves . 5
4.7.3 Loading of continuous sieving machines . 6
4.8 Sieving time . 6
4.8.1 General. 6
4.8.2 End point ruling . 7
4.8.3 Retention time for continuous sieving machines . 7
5 Apparatus . 7
5.1 Sieve media . 7
5.1.1 Shape of aperture . 7
5.1.2 Size of aperture . 7
5.1.3 Construction of sieve media . 7
5.1.4 Sieve frames for hand or mechanical nest sieving . 7
5.2 Sieving machines . 8
5.3 Accessories for wet sieving . 8
5.4 Drying equipment . 9
5.5 Equipment for the determination of mass . 9
6 Samples .10
6.1 Derivation of size sample .10
6.2 Mass of test sample(s) for sieving .10
6.2.1 General.10
6.2.2 Minimum mass .10
7 Procedures .11
7.1 Drying .11
7.2 Division .11
7.3 Preparation and maintenance of sieves for test or nest sieving . .11
7.4 Sieving .12
7.4.1 General.12
7.4.2 Hand placing on individual sieves .12
7.4.3 Hand sieving in the −40 mm to +1 mm range .12
7.4.4 Hand sieving in the −1 mm range.13
7.4.5 Mechanical batch sieving .14
7.4.6 Wet sieving of coarse and fine samples .14
7.4.7 Continuous machine sieving .15
7.5 Determination of mass .15
7.5.1 General.15
7.5.2 Wet sieving — Determination of mass of solids-content in washings .16
7.6 Determination of sieving end point .16
7.6.1 Dry sieving .16
7.6.2 Wet sieving .17
8 Verification .17
8.1 General .17
8.2 Checking of division .17
8.3 Verification of sieve media .17
8.4 Verification of sieving machines .17
8.5 Verification of weighing devices .17
9 Results .17
9.1 Evaluation of results .17
9.2 Calculation and expression of results.18
9.3 Repeatability and acceptance of results .19
10 Test report and working log .20
11 Precision .20
11.1 Overall precision, β . .20
SPM
11.2 Precision of preparation and measurement, β .20
PM
Annex A (informative) Steps for establishing operating conditions .22
Annex B (normative) Scheme of sample preparation and sieving procedure .23
Annex C (normative) Maximum mass to be retained at completion of batch sieving .24
Annex D (informative) Size apertures in R20 and R40/3 series .26
Annex E (informative) Typical batch sieving apparatus .27
Annex F (informative) Desirable features of mechanical sieving machines .
...