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1、INTERNATIONAL STANDARD IS0 540 Third edition 1995-03-I 5 ANSI Intewnat Doe Set Solid mineral fuels - Determination of fusibility of ash - High-temperature tube method Combustibles min b) it shall provide an adequate zone of uniform tem- perature in which to heat the test piece(s); c) it shall provid
2、e means of heating the test piece(s) at a uniform rate from 815 “C upwards; d) it shall be capable of maintaining the required test atmosphere (see 7.1) around the test piece(s); e) it shall provide means of observing the change of shape of the test piece(s) during heating. NOTE 3 It is recommended
3、to provide a facility for in- serting, between the end window of the furnace and the optical viewing instrument, a piece of cobalt-blue glass or similar to protect the retina of the operator from radiation emitted at elevated temperatures. 6.2 Pyrometer, comprising a platinum/platinum- rhodium therm
4、ocouple. 6.3 Mould, of brass, stainless steel or other suitable material, for preparing the test piece. 6.4 Support for the test piece, of such a material that it becomes neither distorted, nor reacts with nor absorbs the ash during the determination. Supports of sintered alumina or fine-textured mu
5、llite are gener- ally satisfactory, but difficulties may arise with indi- vidual ashes, in which case a non-absorbent interface such as platinum foil may be used between the orig- inal support and the test piece. 6.5 Flowmeters, two, for measuring the com- ponents of the reducing gases (see 7.1); it
6、 is not necessary to measure the flow rate when using oxidizing gas. NOTE 4 If the flowmeter contains a liquid, this shall be a non-volatile oil. 6.6 Agate mortar and pestle. 6.7 Test sieve, of aperture 0,075 mm and diameter either 100 mm or 200 mm, complete with lid and re- ceiver. 6.8 Optical inst
7、rument, which enables the profile of the test piece to be observed throughout the de- termination; the relative dimensions of the profile can be conveniently assessed by using a graticule. Additional use of a camera or video equipment is op- tional but recommended. 7 Test conditions 7.1 Test atmosph
8、ere The reducing atmosphere is obtained by introducing into the furnace one of the following mixtures of gases at a minimum linear rate of flow past the test piece of 400 mm/min, calculated at ambient tem- perature; the rate is not critical, provided that it is sufficient to prevent any leakage of a
9、ir into the fur- nace. a) 55 % (V/v) to 65 % (V/v) carbon monoxide with 35 % (V/v) to 45 % (V/V) carbon dioxide; or b) 45 % W/v) to 55 % (Vrv) hydrogen with 45 % WI4 to 55 % (V/v) carbon dioxide. An oxidizing atmosphere is obtained with air or carbon dioxide; the rate of flow is not critical. WARNIN
10、G - When using the reducing atmos- pheres given above, the gases emerging from the furnace will contain a proportion of carbon mon- oxide; it is essential, therefore, to ensure that these gases are vented to the outside atmos- 2 Copyright International Organization for Standardization Provided by IH
11、S under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 00:57:40 MDTNo reproduction or networking permitted without license from IHS -,-,- 0 IS0 IS0 540:1995(E) phere, preferably by means of a hood or an ef- ficient fan system. If hydrogen is used in the re
12、ducing atmosphere, great care shall be taken to prevent an explosion occurring, by purging with carbon dioxide both prior to the introduction of the hydrogen and after the hydrogen supply is shut off. 7.2 Shape of test piece The test piece shall have sharp edges to facilitate ob- servation. The mass
13、 of the test piece shall be such as to ensure equalization of the temperature within the test body. Hence, dimensions that are too large shall be avoided. The following shapes are acceptable: a) pyramid, the base of which is an equilateral tri- angle; the height shall not exceed 19 mm and shall be t
14、wo to three times the length of the side of the base (see figure 1); b) cube of side 3 mm to 7 mm (see figure2); c) upright cylinder of height 3 mm to 9 mm and with diameter equal to the height (see figure2); d) truncated cone of height 4 mm and with diam- eters 3 mm at the base and I,5 mm at the to
15、p (see figure 3). NOTE 5 If, when using the pyramidal test piece, the de- gree of bending becomes severe enough to preclude the direct observation of the dynamic state of the test piece at any time during the test, another shape should be used. Original rl: radius of the hemisphere Deformation Spher
16、e Hemisphere Figure 1 - Characteristic shapes of the pyramidal test piece T 1/3rq Flow L!2 I_ 2r2 4 Original Deformation Sphere Hemisphere FLOW r2: radius of the hemisphere Figure 2 - Characteristic shapes of the cylindrical or cubical test piece 3 Copyright International Organization for Standardiz
17、ation Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 00:57:40 MDTNo reproduction or networking permitted without license from IHS -,-,- Original 1-3: radius of the hemisphere Deformation Sphere Hemisphere Flow Figure 3 - Characteristi
18、c shapes of the truncated-cone test piece 8 Calibration check Check the pyrometer regularly under routine test conditions by observations of the melting point of gold (5.3) and, if possible, the melting point of palladium (5.5). Test the reducing atmosphere by observing the melting point of nickel (
19、5.4). If the observed melting points for gold or palladium differ by more than 10 “C from the melting points given in 5.3 and 5.5, readjust or recalibrate. NOTE 6 An alternative to the observations of the melting points of gold and palladium is to check the pyrometer using a thermocouple certified b
20、y a recognized reference labora- tory or with a calibration which is traceable back to a stan- dard reference laboratory. If the observed melting point for nickel differs by more than 10 “C from the melting point give in 5.4, it can be due to oxidation of nickel caused by an insuf- ficiently reducin
21、g atmosphere. Examine the apparatus for leakages, control the flow rate and the quality of the gases, and recheck the melting point of nickel. NOTE 7 The correct melting point of nickel is not a guarantee that the composition of the reducing atmosphere is correct, as deviations should be considerabl
22、e before the fusibility is affected. 9 Preparation of the test piece Prepare the ash according to the method specified in IS0 1171. Ensure that the incineration is complete. Grind the ash in an agate mortar (6.6) until the maxi- mum particle size is less than 0,075 mm. Moisten a sufficient quantity
23、of the prepared ash with demineralized water or, if necessary, with an adhesive dextrin solution (5.11, make into a paste and press into the mould (6.3). To facilitate the removal of the test piece, the mould may first be coated with a thin layer of petroleum jelly (5.2). Allow the test piece to dry
24、, mount it on its support (6.41, and remove any organic matter by heating it slowly in air up to a temperature of about 815 “C. If preferred, this preliminary heating may be carried out in the furnace (6.1) used for the test. 10 Procedure Transfer the test piece on its support (6.4) to the fur- nace
25、 (6.11, and adjust the composition and flow rate of the atmosphere, taking into account the warning in 7.1. Raise the temperature to a point below the expected deformation temperature, so that the temperature in- terval between the point and the expected defor- mation temperature exceeds 150 “C. The
26、n proceed to raise the temperature at a uniform rate within the range of 3 “Urnin to 7 “C/ min; for small test pieces, which are common in heating microscopes with tube diameters of about 20 mm, a rate up to 10 “C/min will be satisfactory. Record the temperatures at which the characteristic changes
27、of shape occur. With some ashes, difficulties may be encountered owing to such effects as blis- tering, distortion, shrinkage, swelling, non-wetting of the support (caused by high surface tension) and bursting of internal gas bubbles, and in such cases it is desirable to record these phenomena and p
28、ossibly 4 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 00:57:40 MDTNo reproduction or networking permitted without license from IHS -,-,- 0 IS0 repeat the experiment using a d
29、ifferent type of sup- port. 11 Precision of the method 11 .I Repeatability limit The results of independent duplicate determinations, carried out within a short interval of time in the same laboratory by the same operator using the same ap- paratus on the same preparation of ash, shall not dif- fer
30、by more than the values given in table 1. 11.2 Reproducibility limit The means of the results of duplicate determinations, carried out in each of two different laboratories on representative portions taken from the same ash sample prepared as specified in IS0 1171, shall not differ by more than the
31、values given in table 1. IS0 540:1995(E) 12 Test report The test report shall contain the following information: a) an identification of the product tested; b) the reference of the method used; c) the deformation temperature, rounded to the nearest 10 “C; d) the sphere temperature, rounded to the ne
32、arest 10 “C; e) the hemisphere temperature, rounded to the nearest 10 “C; f) the flow temperature, rounded to the nearest 10 “C; g) the type of the atmosphere (reducing or oxidizing); h) any unusual features noted during the determi- nation; i) any operation not included in this International Standa
33、rd. Table 1 Fusibility of ash Maximum acceptable differences between results Repeatability Reproducibility All atmospheres Reducing atmosphere Oxidizing atmosphere Deformation temperature, DTI) 30 “C 80 “C 80 “C Sphere temperature, ST 30 “C 60 “C 40 “C Hemisphere temperature, HT 30 “C 60 “C 40 “C Fl
34、ow temperature, FT 50 “C 80 “C 50 “C I 1) If the sphere temperature is not reached, the precision on deformation temperature may not be achievable. 5 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for
35、 Resale, 04/26/2007 00:57:40 MDTNo reproduction or networking permitted without license from IHS -,-,- IS0 540:1995(E) KS 75.160.10 Descriptors: fossil fuels, solid fuels, ashes, tests, high temperature tests, determination, fusibility. Price based on 5 pages Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/26/2007 00:57:40 MDTNo reproduction or networking permitted without license from IHS -,-,-