1、INTERNATIONAL STANDARD First edition 1997-03-01 Carbonaceous materials used for the production of aluminium - Cathode blocks and prebacked anodes - Determination of the density in xylene by a pyknometric method Produits carbon a=400net; p=iso; o=isocs; s=central Printed in Switzerland ii INTERNATION
2、AL STANDARD o Iso IS0 9088:1997(E) Carbonaceous materials used for the production of aluminium - Cathode blocks and prebaked anodes - Detemination of the density in xylene by pyknometric method 1 Scope This International Standard specifies a pyknometric method for the determination of the true densi
3、ty in xylene of cathode blocks and prebacked anodes used for the production of aluminium. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated
4、were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid Internat
5、ional Standards. IS0 3507: 1976, Pyknometers. IS0 8007: 1985, Carbonaceous materials used in the production of aluminium - Sampling from cathodic blocks and prebaked anodes - General. 3 Principle The true density of cathode blocks and prebaked anodes is measured in xylene in a pyknometer after degas
6、sing under a vacuum. 4 Reagents and materials During the determination, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water, or water of equivalent purity, degassed by boiling for 1 h. 4.1 Ethanol, 95 % (V/V). 4.2 Acetone. 4.3 Sulfuric acid, density app
7、rox. I,84 g/ml, about 98 % (m/m) solution. 1 ISO9088:1997(E) IS0 4.4 Xylene, commercial grade, density about 0,86 g/ml. WARNING - Xylene burns the skin and can also be absorbed into the system through the skin. In addition, inhalation of the vapour from hot material is to be avoided. 5 Apparatus 5.1
8、 Pyknometer, type 3 as defined in IS0 3507 (Gay-Lussac), capacity 25 ml. 5.2 Degassing apparatus (see figure I), comprising the following items: 52.1 Container (1) for the pyknometer, consisting of a glass beaker (2) with removable lid (3) and O-ring (4), capable of containing the pyknometer without
9、 its stopper. The container outlet (5) is connected to a pump (not shown). + 5.2.2 Filling device (6), fitted to the container by a ground-glass joint (7). A tube (8) extends down into the pyknometer. A reservoir (9) with a ground-glass stopper (10) contains the pyknometer liquid which is allowed to
10、 flow into the pyknometer through a teflon valve (11). 5.2.3 Stand (12), to support the beaker when no vacuum is applied to the degassing apparatus. A rod (13) with a spring (14) allows the beaker (Z),with the pyknometer in it, to be shaken to facilitate the evolution of a gas bubbles during degassi
11、ng. The apparatus is made of glass. A rotary pump is connected to the outlet of the apparatus via an oil trap (15). A manometer (16) is connected to the vacuum system between the pump and the oil trap. The vacuum is adjusted so that the manometer, which is about 600 mm from the joint (7) between the
12、 container and the filling device, registers I,3 kPa + 0,3 kPa. A valve (17) is fitted to allow air back into the apparatus. This has to be done slowly and with due care. NOTE - At a pressure of I,3 kPa + 0,3 kPa and an ambient temperature of 25 OC, slight vapourization of xylene may occur until equ
13、ilibrium is reached, but this is of no consequence. The apparatus described above is only an example; other apparatus with the same characteristics may be used. 5.3 Drying oven, capable of being maintained at 120 “C + 2 “C. 5.4 Thermostatically controlled bath, capable of being maintained at 25 “C k
14、 0,05 OC. 5.5 Grinder, capable of grinding the sample to a particle size of less than 63 pm. The parts which come into contact with the sample shall be made of hardmetal to avoid contamination. 5.6 Filter paper. 5.7 Jaw-type crusher. 6 Sampling Sample in accordance with IS0 8007. 2 IS0 9088:1997(E)
15、Dimensions in millimetres Volume 50 ml I) Container 2) Glass beaker 3) Lid 4) O-ring 5) Outlet 6) Filling device 7) Ground-glass joint 8) Tube 9) Reservoir Voiume 330 ml 10) 11) 12) 13) 14) 15) 16) 17) Ground-glass stopper Teflon valve Stand Rod Spring Oil trap Manometer Valve -12 Figure 1 - Typical
16、 degassing apparatus IS0 9088:1997(E) IS0 7 Procedure 7.1 General Carry out all weighings to an accuracy of 0,l mg. When the pyknometer contains a liquid, stabilize its temperature in the thermostatically controlled bath (5.4) at 25 “C + 0,05 “C before weighing. 7.2 Preparation of the sample Drill a
17、 cylinder or cut a piece out of the carbon block and crush it into small pieces using the jaw-type crusher (5.7). Grind the sample to a particle size of c 63 pm using the grinder (5.5). Store the ground material in an airtight container until required for the determination. Before the determination,
18、 dry the sample in the drying oven (5.3) at 120 “C ml is the mass, in grams, of the pyknometer filled with distilled and degassed water; 0,99705 is the density of water, in grams per millilitre, at 25 “C. 4 0 IS0 IS0 9088:1997(E) Determine the pyknometer volume several times on different days to eli
19、minate the effect of external influences, as well as any small differences in the temperature of the bath. The result shall be taken as the mean of 8 to 10 determinations. Individual values shall not deviate from the mean value by more than + 0,001 5 ml. Round the result to the nearest 0,001 ml. 7.3
20、.3 Frequency of calibration Repeat the calibration at least every 3 months. The mass mg shall remain constant to + 1 mg. NOTE - Since no two pyknometers have exactly the same volume, each pyknometer has to be calibrated individually. It is not necessary to check the volume every time the pyknometer
21、is used for a series of density determinations, for instance, although it is usual to check the mass each time. 7.4 Determination of the density of the xylene (4.4) Follow the procedure described in 7.3.2. The density of the xylene, px, the equation expressed in grams per millilitre, is given by Px
22、= m2 - mo V where mg and V are as defined in 7.3.2; m2 is the mass, in grams, of the pyknometer filled with xylene (4.4). The result shall be external in fluences as the mean of 10 determinations made over a number of days to eliminate the effect of 7.5 Determination of the density of the sample 7.5
23、.1 Test portion Weigh, to the nearest 0,l mg, 5 g + 0,l g of the sample (see 7.2) (mass m3) into the clean, dry, empty pyknometer, prepared in accordance with 7.3.1. 7.5.2 Determination The determination shall not be carried out if the ambient temperature exceeds 30 “C. Place the pyknometer, contain
24、ing the test portion but without its stopper, in the container of the degassing apparatus (5.2). Before adding xylene, evacuate for 15 min to a residual pressure of I,3 kPa + 0,3 kPa with the xylene feed closed. This pressure is necessary for a repeatability of Px is as defined in 7.4; m3 is the mas
25、s, in grams, of the test portion (see 7.5.1); mfl is the mass, in grams, of the pyknometer containing the test portion and xylene. Round the result to the third decimal place. 8.2 Precision 8.2.1 General The precision data for this method were obtained in accordance with IS0 5725:1986, Precision of
26、test methods - Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests (now withdrawn). 8.2.2 Repeatability, I- The results of two determinations carried out on the same sample under repeatability conditions (same operator, same apparatus, short time i
27、nterval between the determinations) may be considered to be acceptable if they do not differ by more than 0,004 g/ml. 8.2.3 Reproducibility, R The results of two determinations carried out on the same sample under reproducibility conditions (different operators, different apparatus, different times)
28、 may be considered to be acceptable if they do not differ by more than 0,006 g/ml. 6 0 IS0 9 Test report IS0 9088:1997(E) The test report shall include the following particulars: a) all details necessary for identification of the sample; b) a reference to this International Standard; c) the result o
29、f the determination, and the units in which it has been expressed; d) details of any unusual features noted during the determination; e) details of any operation not included in this International Standard or in the International Standards to which reference is made, as well as any operation regarde
30、d as optional. This page intentionally left blank This page intentionally left blank IS0 9088:1997(E) ICS 71.100.10 Descriptors: extractive metallurgy, aluminium, carbon electrodes, carbonaceous materials, tests, determination, density (mass/volume), xylenes, pycnometric analysis. Price based on 7 pages
