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1、International Standard INTERNATIONAL ORGANIZATION FOR STANOARDIZATION*MEKAYHAPOHAfl OPTAHBAUMR flOCTAHAPTM3AUMklORGANlSATlON INTERNATIONALE DE NORMALISATION 1 b$ .:r+!i .* .“: Carbonaceous materials for the production of aluminium - Calcined coke - Determination of apparent oil content - Heating met
2、hod Prod B : simplified determination (6.2.2); 2 References IS0 565, Test sieves - Woven metal wire cloth, perforated plate and electroformed sheet - Nominal sizes of openings. IS0 5725, Precision of test methods - Determination of repeatability and reproducibility by inter-laboratory tests. IS0 637
3、5, Carbonaceous materials for the production of aluminium - Cokes for electrodes - Sampling. 3 Principle Heating of a test portion in a non-oxidizing atmosphere at a fixed temperature and determination of the loss in mass. Calculation of the apparent oil content in terms of loss of mass. To ensure a
4、 non-oxidizing atmosphere, add some drops of toluene to the crucibles. Sampling shall be carried out according to the procedure specified in IS0 6375. 5.2 Preparation of test sample Using a mortar and pestle, crush approximately 200 g of the laboratory sample (see IS0 6375) sufficiently to pass thro
5、ugh a sieve of nominal mesh apertures 4 mm (see IS0 565). Dry the crushed and sieved product in the electric oven (4.21, con- trolled at a temperature between 105 and 110 OC, for 1 h, or a longer period, until two successive weighings do not differ by more than 0,Ol g. 6 Procedure 6.1 Test portion H
6、eat two of the crucibles, with their lids (4. I), for about 1 h in the electric furnace (4.3) at a temperature of about 800 OC. Allow them to cool to ambient temperature in a desiccator and weigh each of them, without their lids, to the nearest 0,001 g. Weigh into each crucible, to the nearest 0,001
7、 g, a test portion of approximately 75 g from the test sample (5.2). Add a few drops of toluene to the crucibles to ensure a non-oxidizing at- mosphere. 1 -,-,- IS0 6997-1986 (El 6.2 Determination where 6.2.1 A : Normal and reference determination Put the lids on each of the porcelain crucibles cont
8、aining the test portion (6.1) and place them in the steel box (4.4). Embed the crucibles into screened petroleum coke of a particle size of 0,25 to 2 mm, as indicated in the figure. Cover the steel box and place it in the cold electric furnace (4.3). Heat up the fur- nace to a temperature of 550 I/Z
9、 10 OC and maintain this temperature for 2 h. After this period, shut down the furnace and let it cool. Remove the steel box from the furnace and take out the porcelain crucibles. Take care to avoid contamination of the samples with petroleum coke particles of the packing material. Brush and wipe aw
10、ay adhering dust from the still covered crucibles and place them in a desiccator to cool to room temperature. Remove the lids and weigh each crucible with its contents, to the nearest 0,001 g. NOTE - The determination may be also carried out introducing di- rectly the steel box containing the crucib
11、les in the furnace heated to 550 rt 10 “C. In this case, the box should be left in the furnace for 2.5 h. After this period remove the box from the hot furnace and let it cool covered on a refractory plate. Then proceed as indicated above. 6.2.2 B : Simplified determination Put the lids on each of t
12、he porcelain crucibles containing the test portion (6.1) and place them in the electric furnace, previously heated to 500 I!I 10 “C. Wait until the temperature of the furnace, which falls, returns to the value indicated, and maintain the crucibles at this temperature for 20 min. After this period, r
13、emove the crucibles from the furnace and allow them to cool slightly on a refractory plate. Transfer them to a desic- cator and allow to cool to ambient temperature. Remove the lids, and weigh each crucible with its contents, to the nearest 0,001 g. 7 Expression of results 7.1 Method of calculation
14、The apparent oil content, expressed as a percentage by mass, is given by the formula m - m2-x 100 m0 m. is the mass, in grams, of the test portion (6. I); ml is the mass, in grams, of the crucible containing the test portion before heating; m2 is the mass, in grams, of the crucible containing the te
15、st portion after heating. Report the mean value to the nearest 0,Ol % of two simultaneous determinations. 7.2 Precision (according to IS0 5725) 7.2.1 A : Normal determination (six laboratories) m (mean) = 0,256 % r (repeatability) = 0,050 R (reproducibility) = 0,078 7.2.2 B : Simplified determinatio
16、n (same sample; three laboratories) m (mean) = 0,237 % r (repeatability) = 0,036 R (reproducibility) = r (because of the negative value of the variance of reproducibility) The results are rounded to the third decimal place. 8 Test report The test report shall include the following particulars : a) a
17、n identification of the sample; b) the reference of the method used normal reference determination (6.2. I) or simplified determination (6.2.2)1; c) the results and the method of expression used; d) any unusual features noted during the determination; e) any operation not included in this International Stan- dard or in the International Standards to which reference is made, or regarded as optional. 2 -,-,- M 2 6 F ii is k d I ?i 5 ii: 3