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ORGAN I Z AT I ON FOR STAN DARD IZATl O N
I N T ERN AT I ON A L
IS0 RECOMMENDATION
R 728
SIZE ANALYSIS OF COKE
1st EDITION
May 1968
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The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 728, Size analysis of coke, was drawn up by Technical Committee
ISO/TC 27, Solid mineral fuels, the Secretariat of which is held by the British Standards Institution
(BSI).
Work on this question by the Technical Committee led, in 1963, to the adoption of a Draft
IS0 Recommendation.
t
In March 1964, this Draft IS0 Recommendation(No. 683) was circulated to all the IS0 Member
Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by the
foliowing Member Bodies :
Australia Germany South Africa,
Rep. of
Austria India
Switzerland
Belgium Italy
Canada Korea, Rep. of Turkey
U.A.R.
Chile Netherlands
New Zealand United Kingdom
Colombia
Czechoslovakia U.S.A.
Poland
Denmark Romania U. S. S. R .
One Member Body opposed the approval of the Draft :
France
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council
which decided, in May 1968, to accept it as an IS0 RECOMMENDATION.
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ISO/R 728-1968 (E
IS0 Recommendation R 728 May 1968
SIZE ANALYSIS OF COKE
1. SCOPE
This IS0 Recommendation describes the method of determining the particle size distribution of a
sample of coke greater than 20 mm top size.
2. PRINCIPLE
The sample of coke is subjected to a process of size analysis by a specified procedure and the results
expressed in terms of the cumulative percentages by mass of coke remaining on sieves of different
sized apertures.
3. APPARATUS
3.1 Sieves
A series of sieves of perforated plate or wire mesh with round or square apertures of suitable
sizes (see Notes 1 and 2, page 8).
3.2 Weighing machine
A weighing machine, preferably of the platform type, of suitable capacity and such that the
weighing error does not exceed O. 1 of the maximum mass of sample taken, or 1 O0 g, which-
ever is the smaller.
4. SAMPLE
The sample should be representative of the coke under consideration and should not weigh less than
100 kg*. This mass may be reduced as indicated in Table 1 if the nominal upper size limit of the
coke is 60 mm or below.
TABLE 1 - Minimum mass of sample for size analysis
I Nominal upper size of coke (mm) 1 60 1 50 1 40 1 30 I
Minimum mass of sample (kg) 80 55 30 30
*
The mass of sample is given here as a minimum only and does not preclude a greater mass being taken if desired
(as in the example quoted in Table 1); this minimum mass is stated provisionally and may be amended when the
recommended methods of sampling coke are available.
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ISOlR 728-1968 (E
If the coke is excessively wet, the different size fractions will have different moisture contents; this
will lead to variable errors in the determined masses of the various size fractions and hence in the
calculated size analysis. Errors may also be caused by adhesion of small particles to larger ones.
Accordingly, if the coke has a mean moisture content of more than 5 or is visibly wet, it should be
dried to a mean moisture content not exceeding 5 before sieving.
5. PROCEDURE
Select a set of sieves suitable for the purpose (see Notes 1 and 2, page 8) and, if possible, such that no
size fraction will exceed about 25 by mass of the sample; arrange the sieves in a stack in order of
size of aperture with the smallest at the bottom.
Weigh the sample of coke, in several batches if necessary.
Place on the top sieve a quantity of the sample small enough to prevent choking and shake to allow
most of the undersize to pass. Hand-place the coke remaining on the sieve (see Note 3, page 8) and
transfer the oversize to a suitable container. Remove the top sieve and repeat these operations for
sieves of aperture down to 40 mm round (1 1/2 in square).
Continue this procedure for sieves of aperture less than 40 mm round (1 1/2 in square), but using
hand-shaking only (see Note 4, page 8), until the oversize on each sieve has been placed in a separate
container. Mechanical sieving equipment may be used if it is proved to be free from bias (see Note 5,
Page 8).
If necessary, re-stack the sieves and repeat the procedure for successive quantities until the entire
sample has been sized. At the end of each sieving operation, the oversize remaining on the sieve should
not cover more than 75 of the sieving area.
Either weigh separately each container with its size-fraction and subtract the tare masses, or, after
weighmg the fraction of largest size, add successively the other fractions and no
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