1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
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3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-22333-5 SANS 881:2009 Edition 1SOUTH AFRICAN NATIONAL STANDARD Hard coal Determination of caking power Roga test Published by SABS Standar
4、ds Division 1 Dr Lategan Road Groenkloof Private Bag X191 Pretoria 0001 Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS This standard may only be used and printed by approved subscription and freemailing clients of the SABS. SANS 881:2009 Edition 1 Table of changes Change No. Date Scop
5、e Acknowledgement The SABS Standards Division wishes to acknowledge the valuable contribution derived from the publication ISO 335:1974. Foreword This South African standard was approved by National Committee SABS SC 27B, Solid mineral fuels Test methods, in accordance with procedures of the SABS St
6、andards Division, in compliance with annex 3 of the WTO/TBT agreement. This document was published in April 2009. Introduction The purpose of the Roga test, which provides one of the parameters adopted for the “International Classification of Hard Coal by Type“ of the United Nations Economic Commiss
7、ion for Europe, is to assess the caking power of a coal under standard conditions. 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 shall not therefore be regarded as alternative methods. This standard ma
8、y only be used and printed by approved subscription and freemailing clients of the SABS.SANS 881:2009 Edition 1 1 Hard coal Determination of caking power Roga test 1 Scope This standard specifies a method of determining the caking power of hard coal by the Roga test. 2 Principle The caking power of
9、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 i
10、s calculated from the results. 3 Reagent Standard anthracite of E.C.E. Code No. 100 A, that has an ash content of less than 4 % on the dry basis and a volatile matter number of 5 % to 6,5 % on the dry, ash-free basis (see NOTE). Before use, the anthracite is carefully sieved on sieves of 0,3 mm and
11、0,4 mm apertures (square). The fraction passing the 0,4 mm sieve and remaining on the 0,3 mm sieve is retained for the test. NOTE An anthracite of E.C.E. Code No. 100 A, that has a different ash and volatile matter content may be used, provided it has been found by experiment to give the same result
12、s, within the tolerances of the method (see clause 8), as those obtained using the standard anthracite. 4 Apparatus 4.1 Balance, sensitive to 0,01 g. 4.2 Crucible, porcelain, that has the following dimensions: external diameter at the top (40 1,5) mm external diameter at the base (20 1,5) mm externa
13、l height (40 1,5) mm wall thickness less than 2 mm This standard may only be used and printed by approved subscription and freemailing clients of the SABS.SANS 881:2009 Edition 1 2 4.3 Lid, of heat-resistant steel plate, 55 mm square, 1,5 mm to 2 mm thick, with a hole 2 mm in diameter in the centre.
14、 4.4 Stirrer, made of wire, that has an 8 mm loop at one end. 4.5 Heat-resistant steel weight, of 110 g to 115 g, of the following dimensions: 31 mm in diameter 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
15、lifting the weight from the crucible. 4.6 Rod. 4.7 Press for compressing the mixture of coal and standard anthracite under a weight of mass 6 kg (see figure 1). 4.8 Electric furnace, with a zone of uniform temperature and a temperature control device capable of maintaining that zone at (850 10) C. 4
16、.9 Drum, with a cover, driving shaft, transmission gear and electric motor, for carrying out the abrasion test on coke. The drum (see figure 2) has a 200 mm internal diameter, is 70 mm deep and is made of 2 mm thick sheet iron. To the inside walls, which shall be perfectly finished, are welded two s
17、ymmetrical 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 four wing-nuts. The drum is fitted with a threaded stub axle which serves to couple it to the driving shaft. NOTE It is convenient to mount two drum
18、s 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 2) rpm. 4.10 Laboratory sieve, made of thin brass sheet, with 1 mm round holes. 4.11 Stopwatch. 4.12 Asbestos plate. 4.13 Brush. 5 Preparation o
19、f sample Crush the sample of air-dried coal to pass a 0,2 mm test sieve. Take care to avoid an excessive production of particles smaller than 0,1 mm. Ensure that not less than 40 % of the total sample consists of particles between 0,1 mm and 0,2 mm. Mix the crushed sample thoroughly for at least 1 m
20、in, preferably by mechanical means. 6 Procedure Carry out duplicate determinations on each sample of coal, but not simultaneously. Weigh a clean, dry crucible, place in it 1 g of the coal and 5 g of the standard anthracite (see clause 3), both weighed to an accuracy of 0,01 g. Mix carefully for 2 mi
21、n with the stirrer, level off the surface and place the steel weight on it. Press for at least 30 s under a weight with a mass of 6 kg. Remove the crucible from the press and cover it with the lid, leaving the steel weight in the crucible. This standard may only be used and printed by approved subsc
22、ription and freemailing clients of the SABS.SANS 881:2009 Edition 1 3 Raise the temperature of the furnace to (850 10) C and insert the crucible (see NOTE below). Check the temperature on the floor of the furnace at the side of the crucible and ensure that the temperature of (850 10) C is regained w
23、ithin 5 min from the insertion of the crucible. After a total heating time of 15 min, remove the crucible from the furnace and allow it to cool on an asbestos plate for 45 min. NOTE For convenience, a second crucible may be heated in the furnace at the same time; it is emphasized, however, that dupl
24、icate determinations on a single sample of coal are not carried out simultaneously. After cooling, remove the weight from the crucible by means of the rod. Brush back into the crucible any particles of coke adhering to the weight and weigh the crucible plus contents to an accuracy of 0,01 g. Transfe
25、r the contents of the crucible very carefully to the sieve. Carefully transfer back to the crucible the larger pieces of coke, using a pair of tweezers. Sieve the remaining coke very carefully and transfer the oversize back to the crucible. Reweigh the crucible plus contents. Transfer the contents o
26、f the crucible to the drum and fit the cover. Connect the drum to its axle, start the stopwatch and rotate the drum for 5 min at a speed of (50 2) rpm. Remove the coke from the drum and sieve it again. Transfer the coke remaining on the sieve back to the crucible and reweigh. Return the coke from th
27、e crucible to the drum and repeat the abrasion procedure, sieving and reweighing of the oversize exactly as described above. Carry out a third abrasion test under the same conditions, sieve and weigh the final oversize. All weighings are made to an accuracy of 0,01 g. 7 Expression of results The Rog
28、a Index (R.I.) is given by the formula R.I. = + + + 4 3 5 2 1 2 3 100 m m m m mwhere m 1is the total mass, in grams, of crucible coke after carbonization; m 2is the mass, in grams, of coke remaining on the sieve before the first abrasion test; m 3is the mass, in grams, of coke remaining on the sieve
29、 after the first abrasion test; m 4is the mass, in grams, of coke remaining on the sieve after the second abrasion test; m 5is the mass, in grams, of coke remaining on the sieve after the third abrasion test. Report the Roga Index to the nearest integer, as the mean of the results of two separate de
30、terminations which do not differ by more than three units (see clause 8). Where the difference is greater, repeat the test. This standard may only be used and printed by approved subscription and freemailing clients of the SABS.SANS 881:2009 Edition 1 4 8 Precision of determination 8.1 Repeatability
31、 The results of duplicate determinations, carried out at different times, in the same laboratory by the same operator with the same apparatus on the same analysis sample, shall not differ by more than the value in table 1 in table. 8.2 Reproducibility The means of the results of duplicate determinat
32、ions, carried out in each of two laboratories on representative portions taken from the same sample after the last stage of sample preparation, shall not differ by more than the value. Table 1 Precision of results 1 2 Maximum acceptable difference between results Same laboratory (Repeatability) Diff
33、erent laboratories (Reproducibility) Caking power (R.I. Index) 3 units 5 units 9 Test report The test report shall include the following particulars: a) a reference to the method used; b) the results and the method of expression used; and c) any unusual features noted during the determination. This
34、standard may only be used and printed by approved subscription and freemailing clients of the SABS.SANS 881:2009 Edition 1 5 Dimensions in millimeters Figure 1 Press used for compressing the mixture of anthracite and test coal This standard may only be used and printed by approved subscription and f
35、reemailing clients of the SABS.SANS 881:2009 Edition 1 6 Dimensions in millimeters Figure 2 Drum used for abrasion test SABS This standard may only be used and printed by approved subscription and freemailing clients of the SABS. SABS Standards Division The objective of the SABS Standards Division i
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