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UDC 662.6
IS0
I NT E R NAT I ON AL ORGAN I ZATl O N FOR STAN DA RD I ZATl O N
I SO R ECO M M EN DATI O N
R 335
DETERMINATION OF CAKING POWER OF COAL
BY THE ROGA METHOD
1st EDITION
August 1963
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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 335, Determination of Caking Power of Coal by the Roga
Method, was drawn up by Technical Committee ISO/TC 27, Solid Mineral Fuels, the Secretariat
of which is held by the British Standards Institution (B.S.I.).
Work on this question by the Technical Committee began in 1953 and led, in 1957, to the
adoption of a Draft IS0 Recommendation.
In May 1958, this Draft IS0 Recommendation (No. 239) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial
nature, by the following Member Bodies:
Austria Greece Poland
Belgium lndia Portugal
Burma Italy Romania
Canada Japan Spain
Czechoslovakia Mexico Turkey
United Kingdom
Denmark Netherlands
Germany New Zealand U.S.S.R.
Yugoslavia
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 August 1963, to accept it as an IS0 RECOMMENDATION.
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IÇO/R 335 - 1963 (E)
IS0 Recommendation R 335 August 1963
DETERMINATION OF CAKING POWER OF COAL
BY THE ROGA METHOD
1. INTRODUCTION
The purpose of the Roga test, which provides one of the parameters adopted for the " Inter-
national Classification of Hard Coal by Type " of the United Nations Economic Commission
for Europe, is to assess the caking power of a coal under standard conditions.
L
Although the Roga test and the Gray-King test both assess the caking properties of a coal, they
do not measure precisely the same parameters and should not therefore be regarded as alternative
methods.
2. PRINCIPLE
The caking power of a coal is defined by the mechanical strength of the crucible coke obtained by
carbonization under standard conditions of an intimate mixture of 1 g of coal and 5 g of standard
anthracite. The crucible coke obtained is then submitted to a drum test in a strictly prescribed
manner and the Roga Index is calculated from the results.
3. APPARATUS
The balance should be sensitive to 0.01 g.
3.1 Crucible. A porcelain crucible having the following dimensions :
external diameter at the top 40 f 1.5 mm
external diameter at the base 20 1.5 mm
40 f 1.5 mm
external height
wall thickness less than 2 mm
3.2 Lid. A heat-resistant steel plate, 55 mm square, 1.5 to 2 mm thick, with a hole 2 mm in
diameter in the centre.
Stirrer, made of wire, having an 8 mm loop at one end.
3.3
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IÇO/R 335 - 1963 (E)
Heat-resistant steel weight, of 110 to 115 g, of the following dimensions: 31 mm in diameter
3.4
and 21 mm in height, with a threaded hole in the centre 7 mm in diameter and 10 to 12 mm
deep into which can be screwed a suitable rod for lifting the weight from the crucible.
3.5 Press for compressing the mixture of coal and standard anthracite under a weight with the
mass of 6 kg (see Fig. 1, page 5).
3.6 Electric furnace with a zone of uniform temperature and a temperature control device
capable of maintaining that zone at 850 f 10 OC.
3.7 Drum with a cover, driving shaft, transmission gear and electric motor for carrying out the
abrasion test on coke. The drum (see Fig. 2, page 6) has a 200 mm internal diameter, is 70 mm
deep and is made of 2 mm thick sheet iron. To the inside walls, which should be perfectly
finished, are welded two symmetrical sheet iron strips 70 mm long, 30 mm wide and 2 mm
thick. To close the drum, the cover is seated on a felt or rubber gasket and is secured by
4 wing-nuts. The drum is fitted with a threaded stub axle which serves to couple it to the
driving shaft. It is convenient to mount two drums on a single shaft to enable two tests on
two different samples to be carried out simultaneously. The drum is rotated with the stub
axle horizontal at 50 f 2 revolutions per minute.
3.8 Laboratory sieve, made of thin brass sheet, with 1 mm round holes.
3.9 Stopwatch.
3.10 Asbestos sheet.
3.11 Brush.
4. REAGENTS
Standard anthracite. An anthracite of E.C.E. Code No. 100 A, having an ash content of
4.1
less than 4 per cent on the dry basis and a volatile matter number of 5 to 6.5 per cent on the
dry, ash-free basis (see Note below). The anthracite is carefully sieved before use on sieves
of 0.3 mm and 0.4 mm apertures (square), the fraction passing the 0.4 mm sieve and
remaining on the 0.3 mm sieve being retained for the test.
NOTE.- An an
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