1、BRITISH STANDARD BS 1902-3.14: 1996 Methods of testing Refractory materials Part 3: General and textural properties Section 3.14 Determination of hydration tendencyBS1902-3.14:1996 This British Standard, having been prepared under the directionof the Sector Board for Materials and Chemicals, was pub
2、lished under the authority ofthe Standards Board and comesinto effect on 15January1996 BSI08-1999 First published October1987 Second edition January1996 The following BSI references relate to the work on this standard: Committee reference RPI/1 Draft for comment93/309165 DC ISBN 0 580 23736 2 Commit
3、tees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee RPI/1, Physical testing of refractory materials, upon which the following bodies were represented: British Ceramic Research Ltd. British Industrial Ceramic Manufacturers Associati
4、on British Metallurgical Plant Constructors Association British Steel Industry British Vermiculite Association Refractories Association of Great Britain Refractories Contractors Association Society of Glass Technology Amendments issued since publication Amd. No. Date CommentsBS1902-3.14:1996 BSI 08-
5、1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 References 1 3 Designation 1 4 Method for dead-burned magnesia grain, without pressure 1 5 Method for dead-burned magnesia grain, to determine disintegration tendency 2 6 Method for refractory bricks (storage test
6、) 2 7 Method for refractory bricks (accelerated test for destructive service conditions 3 8 Test report 4 Figure 1 Arrangement of crucibles and baffles within the boilingflask(method1902-314/1) 4 List of references Inside back coverBS1902-3.14:1996 ii BSI 08-1999 Foreword This Section of BS1902 has
7、been prepared under the direction of Technical Committee RPI/1. It supersedes BS1902-3.14:1987 which is withdrawn. This revision contains a fourth method for the determination of hydration tendency, which is the second method for the assessment of refractory grain. A British Standard does not purpor
8、t to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance 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 cov
9、er, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS1902-3.14:1996 BSI 08-1999 1 NOTEThis Section should be read in
10、 conjunction with BS1902-3.0 and BS1902-3.1. Section3.0 shows the general arrangement of BS1902 and lists the Sections of Part3. 1 Scope This Section of BS1902 describes methods for the determination of resistance to hydration of both dead-burned magnesia grain used in the manufacture of refractory
11、bricks and magnesia refractory bricks. 2 References 2.1 Normative references This Section of BS1902 incorporates, by dated or undated reference, provisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on the
12、inside back cover. For dated references, only the edition cited applies; any subsequent amendments to, or revisions of the cited publication apply to this Section of BS1902 only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publi
13、cation applies, together with any amendments. 2.2 Informative reference This Section of this British Standard refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but refer
14、ence should be made to the latest editions. 3 Designation The methods for the determination of hydration tendency described in this Section of BS1902 are referred to by the following designations: method1902-314/1 (grain, tested without pressure) method1902-314/2 (grain, tested under pressure) metho
15、d1902-314/3 (bricks, storage test) method1902-314/4 (bricks, accelerated test for destructive service conditions). 4 Method for dead-burned magnesia grain, without pressure 4.1 Principle A sample of raw material is exposed to the action of steam at atmospheric pressure. The resulting chemical reacti
16、on is assessed gravimetrically. 4.2 Apparatus 4.2.1 Porcelain crucible, approximately38mm in height. 4.2.2 Round-bottomed, wide-necked flask, to contain crucible. 4.2.3 Glass beads, to prevent bumping. 4.2.4 Condenser, to prevent loss of water, fitted with a baffle as shown in Figure 1 (see BS5922 f
17、or an example). NOTEA crucible, flask and condenser are required for each determination being conducted in parallel. 4.2.5 Sieves, with apertures of600m and212m, conforming to BS410. 4.2.6 Balance, capable of weighing to0.0005g. 4.2.7 Stoneware mortar and pestle. 4.2.8 Muffle furnace, capable of bei
18、ng controlled at1000 C 10 C. 4.2.9 Drying oven, having openings that promote efficient ventilation. 4.3 Test sample Each test sample shall consist of approximately20g of dead-burned magnesia grain. The sample shall be ground in the mortar (see4.2.7) so that the whole passes through the600m sieve(see
19、4.2.5). The ground sample shall then be sieved through the2124m sieve (see4.2.5), using method1902-303/1, and the fraction remaining on the sieve used for determination. This fraction shall be not less than10g and shall then be split into two portions, each of not less than5g. Each fraction shall be
20、 washed in a suitable non-aqueous solvent e.g.alcohol or ether, to remove the dust, and then dried.BS1902-3.14:1996 2 BSI 08-1999 4.4 Procedure Test the two5g portions simultaneously as follows (see also Figure 1). Introduce the empty crucibles into the furnace(4.2.8) at1000 C and heat for1h at this
21、 temperature; carefully remove the crucibles, cool them in a desiccator to ambient temperature and weigh them (W) to0.0005g. Take the two portions of the test material(see4.3) and place one portion in each crucible. Suspend the crucibles and their contents in a wire cage over boiling water in the fl
22、ask(see4.2.2) and fit the condenser(see4.2.4). Arrange the condenser so that the condensed water is diverted from the crucibles, by using the baffle (see Figure 1). Continue boiling for5h. Remove the crucibles and contents, transfer them to the drying oven(see4.2.9) and dry at110 C 5 C for1h. Weigh
23、each crucible and its contents (W 1 ) to0.0005g, and then ignite them to constant mass at1000 C 10 C in the muffle furnace(see4.2.8), cooling and weighing until two successive weighings do not differ by more than0.001g(W 2 ). 4.5 Calculation of result The percentage loss on ignition using the above
24、procedure, which is the measure of the hydration tendency, H, is given by: The result shall be given to two decimal places. 5 Method for dead-burned magnesia grain, to determine disintegration tendency 5.1 Principle This test is designed to assess the tendency of grains of dead-burned, naturally occ
25、urring magnesias to disintegrate upon hydration. The grains are exposed to the action of steam under pressure. 5.2 Apparatus 5.2.1 Domestic pressure cooker, conforming to BS1746, and capable of maintaining a pressure of0.1MN/m 2 . 5.2.2 Pyrex beaker, to contain sample. 5.2.3 Sieves, with apertures o
26、f2.8mm and1.68mm, conforming toBS410. 5.2.4 Balance, capable of weighing to0.1g. 5.2.5 Drying oven, having openings that promote efficient ventilation. 5.2.6 Electric hot plate or gas ring 5.3 Sample preparation Sieve the magnesia on the2.8mm sieve(see5.2.3) and discard all material passing through
27、the sieve. Large pieces should be pre-crushed to give a size of less than30mm. 5.4 Procedure Weigh approximately500g of the material from5.3 and place in the Pyrex beaker(see5.2.2). Place the beaker on a trivet in the domestic pressure cooker(see5.2.1), containing water to a depth of approximately3c
28、m to4cm. Seal the pressure cooker and heat it on the hot plate or gas ring(see5.2.6) until the pressure reaches0.1MN/m 2then reduce heating to keep the escape of gas to a minimum. Maintain this pressure for20min. Cool the pressure cooker. Remove the sample and dry in the oven(see5.2.5) at150 C for30
29、min. After cooling the sample to room temperature, weigh the sample (W 1 ), and then screen on the1.68mm sieve. The grains that have hydrated appreciably will have disintegrated and be soft enough to brush through the sieve with finger tips. Collect the material that passes through this sieve and we
30、igh (W 2 ). 5.5 Expression of results Calculate the hydration tendency, H, of the grain from the following expression: 6 Method for refractory bricks (storage test) 6.1 Principle A sample of basic refractory brick is exposed to the action of moist air. The test is designed to simulate warm humid con
31、ditions such as could be experienced by exported products. 6.2 Apparatus 6.2.1 Steam humidity cabinet, capable of operation at50 C 1 C and at98% 2%humidity. The cabinet shall be equipped with a circulating air blower and with instruments to record both wet- and dry-bulb temperatures continuously. 6.
32、3 Test pieces 6.3.1 Dimensions Test pieces shall be230mm 30mm (nominally)114mm 76mm in size. They may be either bricks supplied as the required size, or pieces cut from larger blocks.BS1902-3.14:1996 BSI 08-1999 3 6.3.2 Surface finish Where pieces are cut, the cut surfaces shall be coated with a sui
33、table sealant such as pitch or resin having a softening point greater than65 C. Only three cut surfaces shall be included in any test piece; the other three faces, including one230mm 114mm face, shall be the outer skin of the original block. 6.4 Procedure 6.4.1 Place the test pieces in the steam hum
34、idity cabinet(see6.2.1) resting on a230mm 76mm face, and not in contact with either the cabinet walls or other specimens. 6.4.2 Set the steam humidity cabinet to reach50 C 1 C at a humidity of98% 2%. Allow30min to reach these conditions. Maintain the specimens in the cabinet under these conditions f
35、or a further3h. 6.4.3 Remove the test pieces from the cabinet and examine them, reporting in accordance with6.5. Repeat the hydration procedure in6.4.2 on the same specimens for a further3h, and report again. Then repeat the procedure for a further18h before the next report, giving a total of24h. Af
36、ter the first24h, repeat the hydration procedure inspecting at intervals of24h until all test pieces have reached stage4(see6.5). If delays are unavoidable between the successive hydration periods, store the test pieces in airtight containers with a desiccant. 6.5 Interpretation of results Report th
37、e hydration resistance of each test piece qualitatively by visual inspection, rating as follows after each hydration cycle(see6.4.3): 1) unaffected 2) surface hydration or dusting 3) corner or edge disintegration 4) general severe disruption The test report shall include the condition of each test p
38、iece after each cycle. 7 Method for refractory bricks (accelerated test for destructive service conditions) 7.1 Principle A test piece of basic refractory brick is exposed to the action of steam under pressure. This more severe test is designed to simulate destructive service conditions. 7.2 Apparat
39、us 7.2.1 Domestic pressure cooker, conforming to BS1746, containing a perforated platform, and capable of maintaining a pressure of0.1MN/m 2 . 7.2.2 Electric hot plate or gas ring 7.2.3 Measuring device, such as a micrometer or callipers capable of measuring to0.5mm. 7.3 Test pieces 7.3.1 Dimensions
40、. Test pieces shall be rectangular prisms,75mm 2mm (nominally)50mm 50mm, cut from bricks or blocks to include outer skin on three faces. 7.4 Procedure Measure the height of the nominal75mm dimension(see7.2.3) of each test piece to the nearest millimetre, on both an original face and a cut face. Supp
41、ort the perforated platform of the pressure cooker(see7.2.1)50mm above the bottom. Pour water into the cooker until the level is just below the platform. Place the test piece on the platform, with the75mm dimension (height) perpendicular to the base. NOTEA pressure cooker of200mm diameter will hold
42、five test pieces with a minimum10mm gap between each. Put the lid in place with the required weights to give a pressure of0.1MN/m 2 . Using electric or gas heating(see7.2.2) heat the vessel until the pressure is reached, then reduce the heating to keep the escape of steam to a minimum. Maintain the
43、pressure for1h, then cool and remove the test piece for examination. Report the appearance as described in7.5. Replace the test piece in the pressure cooker and repeat the hydration for as many periods of1h as judged necessary to assess the quality of the material. Take care to maintain the water le
44、vel in the cooker. 7.5 Interpretation of results Examine each test piece visually for signs of cracks, expansion, and hydration of grains on the three cut faces. Measure the height of each test piece on the same original face and cut face as in7.4 to the nearest millimetre, and report the percentage
45、 linear expansion for both original and cut faces. NOTEThe test pieces should be handled carefully, particularly during the later stages of hydration, where possible using the original surfaces to grip.BS1902-3.14:1996 4 BSI 08-1999 8 Test report The test report shall include the following informati
46、on: a) the name of the testing establishment; b) the date of the test; c) a reference to these methods of test, e.g.“determined in accordance with method1902-314/1” (see clause3); d) a description of the raw material or refractory product tested (manufacturer, type, batch number); e) the number of t
47、est samples or test pieces; and either f) the individual values for hydration tendency (method1902-314/1,see4.5); or g) the individual values for hydration tendency (method314/2,see5.5); or h) the qualitative rating of the test piece (method1902-314/3, see6.5) and the total time of testing shall be
48、stated; or i) a report of the visual inspection and percentage linear expansion changes after a given time (number of hours), (method1902-314/4, see7.5). NOTEA top condenser, fastened within the bung, may be used instead of a side condenser. Figure 1 Arrangement of crucibles and baffles within the b
49、oiling flask (method1902-314/1)BS1902-3.14:1996 BSI 08-1999 List of references (see clause2) Normative references BSI publications BRITISH STANDARDS INSTITUTION, London BS410:1986, Specification for test sieves. BS1746:1987, Specification for domestic pressure cookers. Informative references BSI publications BRITISH STANDARDS INSTITUTION, London BS1902, Methods of testing refractory materials. BS1902-3, General and textural properties. BS1902-3.0:1983, Introduction. BS1902-3.1:1981, Guidance on sampling. BS1902-3.3:1981, Sieve analy
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