1、BRITISH STANDARD BS 6043-4.7: 1991 Methods of sampling and test for Carbonaceous materials used in aluminium manufacture Part 4: Cold ramming pastes Section 4.7 Preparation of baked rammed test pieces and determination of baked apparent density, change in volume and loss in mass NOTEIt is recommende
2、d that this Section be read in conjunction with the general information in BS6043-4.0, published separately.BS6043-4.7:1991 This British Standard, having been prepared under the directionof the Chemicals Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into
3、 effect on 30September1991 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference CIC/24 Draft for comment 90/54847 DC ISBN 0 580 19889 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Chemical
4、s Standards Policy Committee (CIC/-) to Technical Committee CIC/24, upon which the following bodies were represented: Aluminium Federation British Ceramic Research Ltd. Chemical Industries Association Institute of Petroleum Refractories Association of Great Britain Amendments issued since publicatio
5、n Amd. No. Date CommentsBS6043-4.7:1991 BSI 10-1999 i Contents Page Committees responsible Inside front cover Foreword ii 0 Introduction 1 1 Scope 1 2 Principle 1 3 Definition 1 4 Apparatus 1 5 Materials 1 6 Sampling 1 7 Preparation of test samples 1 8 Procedure 2 9 Calculation and expression of res
6、ults 3 10 Test report 3 Appendix A Sequence for testing 4 Figure 1 Flow chart for sequence for testing 4 Table 1 Test sample masses for50mm-high test pieces 2 Publication(s) referred to Inside back coverBS6043-4.7:1991 ii BSI 10-1999 Foreword This Section of BS6043has been prepared under the directi
7、on of the Chemicals Standards Policy Committee to provide a method of test for cold ramming pastes used in the production of aluminium. There is no corresponding International Standard; however, it is intended, upon publication of this Section of BS6043,that it be offered to the International Organi
8、zation for Standardization (ISO) for possible adoption as an International Standard. It is essential that BS6043-4.1and BS6043-4.6be read in conjunction with this Section of BS6043. This standard describes a method of test only, and should not be used or quoted as a specification defining the charac
9、teristics of a product. Reference to this Section should indicate that the method of test used is in accordance with BS6043-4.7:1991. 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. C
10、ompliance 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, pages i and ii, pages1 to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may h
11、ave had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS6043-4.7:1991 BSI 10-1999 1 0 Introduction The baked test pieces produced by this method are suitable for the determination of additional properties including cold crushing strength, electrical
12、 resistivity, apparent porosity, coefficient of thermal expansion, thermal conductivity and ash. Appendix A gives a scheme showing the sequence in which these measurements may be made on the various test pieces. 1 Scope This Section of BS6043describes a method for the preparation of baked rammed tes
13、t pieces with three levels of apparent density from samples of cold ramming paste used in aluminium manufacture. It also describes methods for determination of apparent density, and change in volume and loss in mass resulting from baking. NOTEThe titles of the publications referred to in this standa
14、rd are listed on the inside back cover. 2 Principle Four groups of test pieces are produced from test samples of cold ramming paste by ramming under regulated conditions. Three of these groups each comprise three test pieces50mm in height, and the groups respectively have100%, 97.5%and95% of the max
15、imum rammed apparent density (MRAD). The fourth group comprises two larger test pieces of maximum rammed apparent density, produced by taking the maximum mass of test sample which can be accommodated in the mould of the rammer. The apparent densities, volumes and masses of the test pieces are determ
16、ined before and after baking according to a defined temperature cycle. 3 Definition For the purposes of this Section of BS6043, the definitions given in BS6043-4.1:1991apply, together with the following. test piece a rigid body of fixed dimensions formed from a test sample of cold ramming paste by r
17、amming compaction 4 Apparatus 4.1 Sand rammer, and the other apparatus described in clause4 of BS6043-4.6:1991. 4.2 Baking box, of material heat-resistant to above1000 C with a close-fitting lid and capable of holding all11test pieces (see clause8) with a minimum clearance of10mm between the individ
18、ual test pieces, and between the test pieces and the walls, top and bottom of the box. A typical box is made of silicon carbide with internal dimensions250mm 250mm and a height of100mm. 4.3 Electric furnace, capable of accommodating the baking box (4.2) within a zone of controlled temperature variat
19、ion no greater than 10 C during baking, and capable of being programmed at a ramp rate of100K/h to a maximum temperature of1000 C. 5 Materials 5.1 Metallurigical or regular-grade petroleum coke, calcined, all capable of passing through a test sieve of3mm nominal aperture and having approximately75%(
20、m/m) retained on a test sieve of1mm nominal aperture complying with BS410. NOTEThe coke may be re-used provided its sieve grading is maintained within the specified limits. 5.2 Refractory cement, for sealing the lid of the baking box. 6 Sampling Prepare a representative laboratory sample of the cold
21、 ramming paste in accordance with BS6043-4.1. 7 Preparation of test samples 7.1 General Prepare the test samples described in7.2 and7.3 from the laboratory sample (seeclause6) by the method described in5.5.3 of BS6043-4.1:1991. Weigh all the test samples to the nearest0.1g. 7.2 Test samples for50mm-
22、high test pieces Prepare at least three test samples for each of the three density categories given in Table 1.BS6043-4.7:1991 2 BSI 10-1999 Table 1 Test sample masses for 50 mm-high test pieces 7.3 Test samples for larger test pieces Prepare at least two test samples of sufficient mass to fill the
23、mould of the sand rammer (4.1) to its maximum usable level. 8 Procedure 8.1 Preparation of50mm-high test pieces of specified apparent density levels 8.1.1 100 % MRAD Prepare three test pieces by ramming test samples (see7.2) by the procedure described in7.1 of BS6043-4.6:1991. Weigh and measure each
24、 test piece by the procedure described in7.2 of BS6043-4.6:1991. Reject any test piece which is not50 2mm in height and repeat the procedure with a fresh test sample (see7.2) until three test pieces of the correct height have been obtained. Calculate the apparent densities of the test pieces in acco
25、rdance with clause8 of BS6043-4.6:1991. If the range of the three results for the apparent density is greater than0.01g/mL, reject the test pieces and repeat the procedure using fresh test samples (see7.2). 8.1.2 97.5 % MRAD Prepare three test pieces by ramming test samples with97.5% of the mass of
26、those used in8.1.1 (andsee7.2). Ram each of the samples by the procedure described in7.1 of BS6043-4.6:1991, but use a reduced number of impacts, evenly divided between both faces of the test sample so that the final height of each test piece is502mm. Weigh and measure each test piece by the procedu
27、re described in7.2 of BS6043-4.6:1991. Reject any test piece which is not502mm in height and repeat the procedure with a fresh test sample (see7.2) until three test pieces of the correct height have been obtained. Calculate the apparent densities of the test pieces according to clause8 of BS6043- 4.
28、6:1991. Reject any test piece which differs from the required density by more than0.01g/mL and prepare a replacement test piece by repeating the procedure using a fresh test sample (see7.2). 8.1.3 95 % MRAD Prepare three test pieces by ramming test samples with95%of the mass of those used in8.1.1 (a
29、nd see7.2). Use the ramming, measurement, calculation and validation procedures described in8.1.2 until a group of three acceptable test pieces has been prepared. 8.2 Preparation of larger test pieces of maximum rammed apparent density NOTEThese test pieces are intended for the subsequent determinat
30、ion of the electrical resistivity and other properties of the baked ramming paste (see Appendix A). Prepare two test pieces by ramming larger test samples (see7.3) by the procedure described in7.1 of BS6043-4.6:1991but increasing the number of impacts such that each test sample receives100impacts on
31、 each face, i.e. a total of200impacts per sample. Weigh and measure each test piece following the procedure described in7.2 of BS6043-4.6:1991. Calculate the apparent densities of the test pieces according to clause8 of BS6043-4.6:1991. Reject any test piece which differs from the required density b
32、y more than0.01g/mL and prepare a replacement test piece by repeating the procedure with a fresh test sample (see7.3). 8.3 Pre-curing Cold ramming pastes containing synethetic resin binders may require a pre-curing treatment to polymerize the resin in the rammed test pieces prior to baking, in order
33、 to obtain optimal properties in the final baked product. Carry out the pre-curing of such materials in accordance with the manufacturers instructions. Density relative to maximum rammed apparent density (MRAD) Relative mass of test sample M Mass of test sample a Preparation described in subclause %
34、 g 100 M 170.0 0.1 8.1.1 97.5 0.975M 165.8 0.1 8.1.2 95 0.95M 161.5 0.1 8.1.3 a The masses given are typical examples. The precise mass of the test samples can be decided only after the successful preparation of a test piece of maximum rammed apparent density and height50 2mm (see8.1.1).BS6043-4.7:1
35、991 BSI 10-1999 3 8.4 Baking Place a layer of the coke (5.1) of10mm minimum depth on the bottom of the baking box (4.2). Arrange the11test pieces (8.1 and8.2) on the coke bed so that there is a minimum gap of10mm around each test piece. Note the positions of the individual test pieces. Surround and
36、cover the test pieces with more coke, ensuring that the depth of coke above the highest point of the test pieces is at least10mm. Fit the lid to the baking box and seal it with the refractory cement (5.2). Place the baking box in the furnace (4.3) within the zone of uniform temperature. Close the fu
37、rnace. Commence heating the furnace at a rate of100K/h to1000 C, then hold the furnace at1000 C for5h. Allow the furnace and its contents to cool to a temperature close to ambient then remove the baking box. Unpack the baked test pieces taking care to note their position for identification purposes.
38、 Carefully remove any adhering packing coke from the test pieces, if necessary by brushing by hand with a wire brush. Re-weigh and re-measure each cleaned test piece by the procedure described in7.2 of BS6043-4.6:1991. Calculate the apparent densities of the test pieces according to clause8 of BS604
39、3-4.6:1991. 9 Calculation and expression of results 9.1 Apparent density Calculate the mean apparent densities, expressed ing/mL, in the unbaked and baked states for each of the four groups of test pieces from the individual apparent densities calculated in8.1.1 to8.1.3 and8.2 and8.4. Express the re
40、sults to three decimal places. 9.2 Change in volume 9.2.1 Calculate the volume, V, of each of the test pieces, in cm 3 , using the measurements made in the unbaked (8.1 and8.2) and baked (8.4) states using the following equation: where 9.2.2 Calculate the percentage change in volume V of each of the
41、 test pieces as a result of baking (also known as the volume stability), using the following equation: where Calculate the mean percentage value of the change in volume for each of the four groups of test pieces whose preparation is described in8.1 and8.2 and express the result to two decimal places
42、. NOTEPositive values of this parameter indicate net expansion having occurred as a result of baking; negative values indicate net shrinkage. 9.3 Loss in mass Calculate the percentage loss in mass, M, occurring for each test piece as a result of baking, using the following equation: where Calculate
43、the mean percentage value of the loss in mass for each of the four groups of test pieces whose preparation is described in8.1 and8.2, and express the result to one decimal place. 10 Test report The test report shall include the following information: a) a complete identification of the sample of col
44、d ramming paste; b) a reference to this British Standard, i.e.BS6043-4.7:1991; c) the mean values of the unbaked and baked apparent densities, change in volume and loss in mass occurring on baking, for each of the four groups of test pieces in8.1 and8.2, calculated in accordance with clause9; d) any
45、 unusual features noted during the determination; e) any operation not included in this British Standard or regarded as optional. h is the mean height of the test piece (inmm); d is the mean diameter of the test piece (inmm). V h d 2 () 2 1000 - = V 0 is the volume of the unbaked test piece (incm 3
46、); V 1 is the volume of the baked test piece (incm 3 ). M 0 is the mass of the unbaked test piece (in g); M 1 is the mass of the baked test piece (in g). V 100 V 1 V 0 () V 0 - = M 100 M 0 M 1 () M 0 - =BS6043-4.7:1991 4 BSI 10-1999 Appendix A Sequence for testing The following flow chart indicates
47、the sequence in which further determinations may be performed on the four groups of test pieces whose preparation and measurement is described in8.1 and8.2 after they have been baked and measured in accordance with8.4. The boxes indicate the Sections of BS6043which describe the relevant test procedu
48、res. Some of these procedures make essential references to other standards. Details of these other standards are given in BS6043-4.0. Figure 1 Flow chart for sequence for testingBS6043-4.7:1991 BSI 10-1999 Publication(s) referred to BS 410, Specification for test sieves. BS 6043, Methods of sampling
49、 and test for carbonaceous materials used in aluminium manufacture. BS 6043-4, Cold ramming pastes. BS 6043-4.0, General introduction 1) . BS 6043-4.1, Methods of sampling. BS 6043-4.6, Determination of maximum rammed apparent density of unbaked paste. BS 6043-4.8, Determination of the electrical resistivity of baked rammed paste. BS 6043-4.9, Determination of the cold crushing strength of baked rammed paste. BS 6043-4.10, Determi
