BS 1902-3 16-1990 Methods of testing refractory materials - General and textural properties - Determination of pore size distribution (method 1902-316)《耐火材料试验方法 总则和结构特性 气孔尺寸分布测定(19.pdf

1、BRITISH STANDARD BS1902-3.16: 1990 Methods of testing Refractory materials Part 3: General and textural properties Section3.16 Determination of pore size distribution (method1902-316)BS1902-3.16:1990 This British Standard, having been prepared under the directionof the Refractory Products Standards

2、Policy Committee, was published underthe authority of the BoardofBSI and comes into effect on 30 November1990 BSI08-1999 The following BSI references relate to the work on this standard: Committee reference RPM/1 Draft for comment88/44009DC ISBN 0 580 18364 5 Committees responsible for this British

3、Standard The preparation of this British Standard was entrusted by the Refractory Products Standards Policy Committee (RPM/-) to Technical Committee RPM/1, upon which the following bodies were represented: British Ceramic Research Ltd. British Steel Industry Electricity Supply Industry in England an

4、d Wales Engineering Equipment and Materials Users Association Refractories Association of Great Britain Refractory Contractors Association Society of Glass Technology Amendments issued since publication Amd. No. Date CommentsBS1902-3.16:1990 BSI 08-1999 i Contents Page Committees responsible Inside

5、front cover Foreword ii 1 Scope 1 2 Designation 1 3 Definitions 1 4 Principle 1 5 Apparatus 2 6 Test samples 2 7 Procedure 3 8 Calculation of results 6 9 Test report 7 Figure 1 General arrangements of coarse and fine pore measuring devices illustrating two methods of detecting the mercury level in t

6、he capillary 4 Figure 2 Schematic arrangement of sample holder 5 Table 1 Examples of ways of presenting results 6 Table 2 Density of mercury 7 Publications referred to Inside back coverBS1902-3.16:1990 ii BSI 08-1999 Foreword This Section of BS1902-3 has been prepared under the direction of the Refr

7、actory Products Standards Policy Committee. The method is based on measurement of pore size distribution by mercury intrusion. As very high pressures are used in the determination and small volumes of mercury are measured, it is more convenient to use a commercially available apparatus than to const

8、ruct one to comply with this method. The manufacturers operating manuals give details of how their apparatus is to be used. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance

9、with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amen

10、dments incorporated. This will be indicated in the amendment table on the inside front cover.BS1902-3.16:1990 BSI 08-1999 1 NOTEThis Section is to be used in conjunction with BS1902-3.0 “Introduction” and BS1902-3.1 “Guidance on sampling”. Section3.0 shows the general arrangement of BS1902 and lists

11、 the Sections of Part3. 1 Scope This Section of BS1902-3 describes a method for the measurement of pore size distributions of solid and granular refractory material. The method can be used to measure pore diameters in the approximate range0.006m to600m. NOTE 1The assumed model in this method has all

12、 the pores parallel sided and of circular cross section; the results are reported as equivalent pore diameters. A model for pores of different cross section, e.g.elliptical, can be derived by making appropriate adjustments to the mathematics. NOTE 2This method is unsuitable for materials that: a) co

13、ntain volatile compounds which give off vapours when placed under vacuum; b) contain metals that amalgamate with mercury. NOTE 3The titles of the publications referred to in this standard are listed on the inside back cover. 2 Designation The method of determining pore size distribution described in

14、 this Section is referred to by the following designation. Method1902-316. 3 Definitions For the purposes of this Section of BS1902 the following definitions apply. 3.1 item the brick, or bag of granular raw material, which is to be tested 3.2 test sample the portion of sample on which pore size mea

15、surements are made, in the form of a cut piece of brick or of granular particles 3.3 equivalent pore diameter the diameter of a pore at a given pressure which represents the pores of irregular cross section impregnated by mercury at that pressure 3.4 ink bottle pores non-parallel sided pores in the

16、form of an ink bottle with a narrow neck and a wide body, measured as if the whole pore was of the same diameter as the neck 3.5 coarse pores pores with diameters greater than or equal to10m, whose equivalent diameters are measured with the coarse pore measuring device 3.6 fine pores pores with diam

17、eters less than10m whose equivalent diameters are measured with the fine pore measuring device 3.7 mercury filling device apparatus which is made so that only fine pores can be measured, employed to evacuate and fill the sample holder with mercury 3.8 coarse pore measuring device an apparatus for me

18、asuring the proportion of coarse pores present in a sample, combining the functions of mercury filler and pore measurer 3.9 fine pore measuring device an apparatus for measuring the proportion of fine pores present in a sample 3.10 apparent solid density the ratio of the mass of the material to its

19、apparent solid volume, which is the volume of the solid material plus the volume of the closed pores 4 Principle A test sample is placed in a vessel which is evacuated and filled with mercury. The pressure on the mercury is increased to force it into progressively finer pores and measurement of the

20、volume of mercury forced into the pores at different pressures enables the pore size distribution to be determined. The data obtained can also be used to calculate the apparent porosity, bulk density, and apparent solid density of the test sample (see8.4).BS 1902-3.16:1990 2 BSI 08-1999 5 Apparatus

21、NOTEThe general arrangements of coarse and fine pore measuring devices illustrating two methods of detecting the mercury level in the capillary are shown in Figure 1. 5.1 Sample holder, as shown in Figure 2, constructed in such a way that the base of the sample holder and the uniform capillary tube

22、forming the neck can be separated from each other, to allow the test sample to be inserted. The volume of the holder shall be sufficient to accommodate a test sample of not less than1cm 3 . The holder shall be designed so that electrical contact can be made with the mercury in the holder, either by

23、an appropriately designed removeable bottom, or by fusing an electrode through the well. 5.2 Mercury filling device, which may be separate from, or an integral part of the coarse pore measuring device(5.5). This filling device shall be capable of evacuating the sample holder to a pressure of2.67Pa(2

24、0mHg). After evacuation the device shall enable the evacuated sample holder to be filled with mercury by means of a system of valves. 5.3 Mercury, of triple distilled quality. WARNING. It is important that proper precautions for the protection of laboratory personnel are taken when mercury is used.

25、Attention is drawn to the relevant regulations and guidance documents which include the Department of Employment Technical Data Note No.21, published by HMSO 1) . 5.4 Mercury level measuring system, which is fitted to both a coarse pore(5.5) and a fine pore measuring device(5.6) to measure the level

26、 of mercury in the capillary tube which drops as the pressure on the mercury is increased. The system shall be able to measure an intrusion volume to a resolution of greater than1mm 3 . One of the methods described in either5.4 a) or5.4 b) shall be used to measure the intrusion volume. a) The intrus

27、ion volume may be measured by a mechanical method, in which a fine needle can be raised or lowered down the capillary of the sample holder by means of an electric motor. The motor winds the needle down and stops when the needle touches the mercury. Contact is detected by the completion of an electri

28、cal circuit through the needle, mercury and electrode fitted to the sample holder. The position of the needle is recorded electronically by a micrometer screw mechanism fitted to the motor. b) The intrusion volume may be measured by an electronic method, in which the capacitance between the column o

29、f mercury in the capillary and a metal sleeve is measured. The sleeve can either be a surface coating on the sample holder or a separate tube in which the capillary tube fits in the pore measuring device. Electrical contact with the mercury column is achieved by means of the electrode fitted to the

30、sample holder. 5.5 Coarse pore measuring device, as illustrated in Figure 1(a), which comprises a mercury level measuring system(5.4), a means of admitting air (in a controlled manner) to the chamber containing the mercury filled sample holder and a means of recording the pressure in the system to a

31、 resolution of 0.002MPa. Where the device is fitted with a facility for introducing nitrogen or air under pressure, either by means of a pump or from a gas cylinder, some pressures above atmospheric pressure, e.g.up to0.2MPa, may be obtained. 5.6 Fine pore measuring device, as illustrated in Figure

32、1(b), which comprises a pressure vessel, fitted with a mercury level measuring system(5.4) to contain the mercury filled sample holder. The pressure vessel shall be capable of being pressurized up to210MPa, by means of a suitable pumping system and hydraulic fluid. The system for measuring the press

33、ure shall have a resolution of 0.007MPa. NOTEThe approximate limit for fineness of pores measured is0.006m diameter, the size being limited by the pressures developed in the pressure vessel. 6 Test samples 6.1 General Test samples shall comprise particles of maximum size1cm 3and shall be washed to r

34、emove adhering particles (which can affect sample mass and block pores) and dried to constant mass at110 5 C. NOTE 1With particles larger than1cm 3 , mercury is less likely to reach the centre. NOTE 2Liquids other than water should be used to wash samples susceptible to hydration. Some materials may

35、 be affected by heat and an alternative drying procedure should be adopted. 6.2 Bricks At least three pieces, of a minimum total volume of2cm 3 , shall be taken from the item to form the test sample (brick). For porous materials where the volume of the pores is greater than the volume of the capilla

36、ry, it will be necessary to retest with a smaller sample volume (see7.5) and this shall be reported. 1) Available from HMSO,49 High Holborn, London WC1 for personal callers, or by post from HMSO, P.O. Box276, London SW85DT.BS1902-3.16:1990 BSI 08-1999 3 Test samples shall be cut from a brick with a

37、saw or core drill. The pieces shall be sampled to represent different zones of the brick. As there is a possibility that saw marks can be counted as pores, if coarse pores are of particular interest the surfaces of the test sample shall be polished with a medium of maximum particle size10m. If fine

38、pores are of particular interest, the sample shall be tested in the as sawn condition, ignoring pore sizes greater than125m. 6.3 Granular material Samples of granular material shall be taken by coning and quartering or using sample splitters. Crushing granular materials to form particles less than1c

39、m 3shall be kept to a minimum as crushing may introduce cracks that would be counted as pores. 7 Procedure 7.1 General A liquid that has a high contact angle, , with a solid, will not penetrate capillaries of diameter, d, in that solid, unless a pressure, p, is applied. These are related as follows

40、where v is the surface tension: The chosen liquid with this method is mercury which has a contact angle of between130 and145 for many materials. For oxide refractories an angle of130 shall be used in calculations and for refractories containing carbon, an angle of140 shall be used. The surface tensi

41、on of mercury is approximately0.484N/m at25 C and0.472N/m at50 C. During the determination, the temperature of the hydraulic fluid can increase asaresult of the work done on it and a value of0.482N/m shall be used in the calculations unlessotherwise reported. 7.2 Blank determination Carry out blank

42、determination if required (see8.3.1). 7.3 Evacuation Weigh the cleaned dried test sample to0.001g(W 1 ) and place it in a clean dry sample holder. If bulk density, apparent solid density and apparent porosity are required, weigh the sample holder containing the test sample to0.001g(W 2 ). Connect th

43、e sample holder to the vacuum system of the mercury filling device(5.2) or coarse pore measuring device(5.5) and evacuate until the pressure stabilizes at less than6.67Pa(50mHg). If the material does not allow stabilization below6.67Pa the material is not suitable for assessment by this procedure an

44、d the test shall be abandoned. When the pressure has stabilized at the required level, admit the mercury to the sample holder to fill it. NOTE 1For very accurate work the sample holder should be evacuated to less than2.67Pa(20mHg) and the final pressure should be reported. NOTE 2If the test sample i

45、s in granular form (see6.3) there may be areas between particles where surface tension prevents complete filling; these may be measured later as large pores. 7.4 Coarse pore measurement NOTEThis procedure can only be followed if the sample holder has been filled in the coarse pore measuring device(5

46、.5). After filling the sample holder and draining the surplus mercury from the system by means of valves, admit air in a controlled manner. Increase the pressure either: a) almost continuously; NOTEAs ink bottle pores can lead to error, increase the pressure slowly, or hold it constant from time to

47、time, to allow the mercury volume reading to stabilize; b) in stages, corresponding to pressures for particular pore sizes. At the same time record the volume of mercury forced into the pores by either: 1) plotting the mercury level and pressure readings graphically during the test; 2) recording the

48、 pressures and volumes digitally. When the pressure in the system has reached atmospheric pressure, if the system is suitably designed (see5.5), apply a positive pressure (p) by means of compressed gas, e.g.nitrogen or air, to increase the range of measurable pore sizes. After measurements have been

49、 made, reduce the pressure to ambient and remove the sample holder from the apparatus. If a bulk density value is required, weigh the sample holder containing the test sample and mercury to0.001g(W 3 ). d=(1/p)4v cos (1)BS 1902-3.16:1990 4 BSI 08-1999 Figure 1 General arrangements of coarse and fine pore measuring devices illustrating twomethods of detecting the mercury level in the capillaryBS1902-3.16:1990 BSI 08-1999 5 7.5 Fine pore measurement Place the filled sample holder(5.2) in the pressure vessel of the fine pore measuring dev