AS 4538.1-1999

This Standard has been reconfirmed. To view or download the Reconfirmation Notice please click here.

1 - AS 4538.1-1999 GUIDE TO THE SAMPLING OF ALUMINA - SAMPLING PROCEDURES
4 - PREFACE
5 - CONTENTS
6 - 1 SCOPE
6 - 2 REFERENCED DOCUMENTS
6 - 3 DEFINITIONS
6 - 3.1 Bias
6 - 3.2 Coefficient of variation
6 - 3.3 Constant-mass division
6 - 3.4 Cut
7 - 3.5 Divided increment
7 - 3.6 Division
7 - 3.7 Duplicate sampling
7 - 3.8 Fixed-rate division
7 - 3.9 Gross sample
7 - 3.10 Increment
7 - 3.11 Laboratory sample
7 - 3.12 Lot
7 - 3.13 Manual sampling
7 - 3.14 Mass-basis sampling
7 - 3.15 Mechanical sampling
7 - 3.16 Nominal top size
7 - 3.17 Precision
7 - 3.18 Reduction (in particle size)
7 - 3.19 Replicate sampling
7 - 3.20 Sampling unit
7 - 3.21 Stage
7 - 3.22 Standard deviation
7 - 3.24 Stratified random sampling
7 - 3.25 Subsample
7 - 3.26 Superfines
8 - 3.27 Systematic sampling
8 - 3.28 Time-basis sampling
8 - 3.29 Variance
8 - 4 NOTATION
8 - 5 PRINCIPLES OF SAMPLING
8 - 5.1 General
9 - 5.2 Sampling errors
9 - 5.2.1 General
9 - 5.2.2 Accessory error
10 - 5.2.3 Delimitation and extraction errors
10 - 5.2.4 Weighting error
10 - 5.2.5 Periodic quality fluctuation error
10 - 5.3 Sampling variance
11 - 5.4 Overall variance
12 - 5.5 Segregation and contamination
12 - 6 ESTABLISHING A SAMPLING SCHEME
13 - 7 MASS OF INCREMENT
13 - 7.1 General
13 - 7.2 Mass of increment from falling-stream samplers
13 - 7.3 Mass of increment for manual sampling
13 - 7.4 Increment mass for moisture sample
14 - 8 NUMBER OF INCREMENTS
14 - 9 MASS OF LOT AND SUBLOT SAMPLES
14 - 10 MASS-BASIS SAMPLING
14 - 10.1 General
14 - 10.2 Sampling interval
15 - 10.3 Cutters
15 - 10.4 Taking of primary increments
15 - 10.5 Constitution of a gross sample or subsample
15 - 10.6 Methods of division
15 - 10.7 Division of increments
16 - 10.8 Division of subsamples
16 - 10.9 Division of gross samples
16 - 10.10 Number of cuts for division
16 - 11 TIME-BASIS SAMPLING
16 - 11.1 General
17 - 11.2 Sampling interval
17 - 11.3 Cutters
17 - 11.4 Taking of primary increments
17 - 11.5 Constitution of gross sample or subsample
17 - 11.6 Division of increments and subsamples
17 - 11.7 Division of gross samples
17 - 11.8 Number of cuts for division
17 - 12 STRATIFIED RANDOM SAMPLING-FIXED MASS OR TIME INTERVALS
18 - 13 MECHANICAL SAMPLING FROM MOVING STREAMS
18 - 13.1 General
18 - 13.2 Design of the sampling system
18 - 13.2.1 Location of sample cutters
18 - 13.2.2 System for checking the precision and bias
18 - 13.2.3 Avoiding bias
19 - 13.2.4 Minimizing bias
19 - 13.2.5 Arrangement of sampling system
19 - 13.3 Sample cutters
19 - 13.3.1 General
19 - 13.3.2 Falling-stream cutters
20 - 13.3.3 Cutter velocity and effective cutter aperture
21 - 13.4 Routine checking
21 - 14 STOPPED-BELT SAMPLING
22 - APPENDIX A - AN EXAMPLE OF VALIDATION OF AUTOMATIC SAMPLING IN THE ALUMINA INDUSTRY

Sets out a procedure for the sampling of alumina from moving streams, including stopped-belt sampling, to provide samples for chemical analysis, physical testing and determination of moisture content. The procedure is not applicable to the sampling of alumina from fluidized streams, which presents particular sampling problems.

This Guide sets out a procedure for the sampling of alumina from moving streams, including stopped-belt sampling, to provide samples for chemical analysis, physical testing and determination of moisture content.The bulk of this procedure comprises generic sampling concepts that were extracted, in part, from AS 4433.1, and which are common to a diverse range of sampling regimes. Emphasis on alumina sampling is incorporated where appropriate, and a case study of the falling-stream type mechanical autosampler in use at Alcoa of Australia's Kwinana ship-loading facility is cited, to highlight specific requirements for alumina sampling. Procedures for automated cross-belt sampling, sampling from stationary situations and manual sampling from moving streams are not discussed in this document, having been fully detailed in AS 4433.1.Alumina's uniform particle size relative to other non-powder ores contributes to its homogeneous chemical properties, allowing simplified sampling theory to be employed. For a comprehensive description of sampling theory, and variographic techniques, refer to AS 4433.1. Physical segregation during handling and transportation may result in biased size distributions of incorrectly taken samples; the prevention or minimization of such segregation is the main focus of this procedure. This Standard is not applicable to the sampling of alumina from fluidized streams, which presents particular sampling problems.

First published as AS 4538.1-1999.