1、BRITISH STANDARD BS 4140-24: 1987 ISO 8220:1986 Methods of test for Aluminium oxide Part 24: Determination of fine particle size distribution (method using electroformed sieves) ISO title: Aluminium oxide primarily used for the production of aluminium Determination of the fine particle size distribu
2、tion (less than 60 4m) Method using electroformed sieves NOTEIt is recommended that this Part be read in conjunction with the general information given in BS4140-0 “General introduction” which is issued separately. UDC 661.862.22:620.168.32BS4140-24:1987 This British Standard, having been prepared u
3、nder the directionof the Chemicals Standards Committee, was published under the authorityofthe Board of BSIandcomes into effect on 30April1987 BSI 11-1999 The committees responsible for this British Standard are shown inPart 0 The following BSI references relate to the work on this standard: Committ
4、ee reference CIC/24 Draft for comment 84/53017 DC ISBN 0 580 15831 4 Amendments issued since publication Amd. No. Date of issue CommentsBS4140-24:1987 BSI 11-1999 i Contents Page National foreword ii 1 Scope and field of application 1 2 References 1 3 Principle 1 4 Reagents and materials 1 5 Apparat
5、us 1 6 Procedure 1 7 Expression of results 2 8 Cleaning of the sieves 2 9 Test report 2 Figure Typical agitation device for electroformed sieves 3 Publications referred to Inside back coverBS4140-24:1987 ii BSI 11-1999 National foreword This Part of BS4140 is identical with ISO8220:1986 “Aluminium o
6、xide primarily used for the production of aluminium Determination of the fine particle size distribution (less than60m) Method using electroformed sieves” published by the International Organization for Standardization (ISO). Terminology and conventions. The text of the International Standard has be
7、en approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards, it is c
8、urrent practice to use a full point on the baseline as the decimal marker. The symbol “l” has been used to denote litre. In British Standards it is current practice to use the symbol “L”. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British
9、Standard”. The Technical Committee has reviewed the provisions of ISO3310-2:1982, to which reference is made in clause2, and has decided that they are acceptable for use in conjunction with this standard. A related British Standard for ISO3310-2 is BS410:1986 “Specification for test sieves”. This st
10、andard prescribes methods of test only, and should not be used or quoted as a specification defining limits of purity. Reference to this Partshould indicate that the method of test used complies with BS4140-24:1987. A British Standard does not purport to include all the necessary provisions of a con
11、tract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard BS 4140 Methods of test for aluminium oxide ISO 802:19
12、76 Part 1:1986 Preparation and storage of test samples (Identical) ISO 803:1976 Part 2:1986 Determination of loss of mass at300 C (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4, an inside back cover and a back cover. This standa
13、rd 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.BS4140-24:1987 BSI 11-1999 1 1 Scope and field of application This International Standard specifies a method for the determination of the particl
14、e size distribution (less than604m) of aluminium oxide primarily used for the production of aluminium, using electroformed sieves. NOTEThere is no correlation, for the calcined alumina, between the results obtained with the square-aperture and the round-aperture electroformed sieves. The use of eith
15、er kind of sieve should be clearly indicated in the compilation of the test report, as well as in the agreement protocols between suppliers and purchasers if the particle size distribution is indicated in the contract. 2 References ISO 802, Aluminium oxide primarily used for the production of alumin
16、ium Preparation and storage of test samples. ISO 803, Aluminium oxide primarily used for the production of aluminium Determination of loss of mass at300 C (conventional moisture). ISO 3310-2, Test sieves Technical requirements and testing Part 2: Test sieves of metal perforated plate. 3 Principle Qu
17、antitative separation by sieving of the particles in the range63to164m suspended in an aqueous solution of a dispersing agent. The sieves are square-aperture or round-aperture electroformed sieves, depending on their origin. Drying and weighing of each sieved fraction. 4 Reagents and materials Durin
18、g the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Sodium hexametaphosphate (NaPO 3 ) 6 , 1g/l solution. 4.2 Surface active agent, non-ionic polyethoxyl, saturated solution. 5 Apparatus Ordinary laboratory apparatus and 5.1 Ag
19、itation device, for the slow oscillation of the sieves (5.2) placed on a support, driven by a motor equipped with reduction gear and cam, capable of shaking the sieves with a frequency of1Hz and10mm amplitude. A schematic drawing is shown in the Figure. 5.2 Set of electroformed sieves, of maximal di
20、mensions75mm (available diameter65mm), mounted on stainless steel frames and fitted with a cloth for supporting the electroformed membrane. The sizes of the apertures shall be634532164m. The tolerances shall be those required by ISO3310-2. NOTEElectroformed sieves of80 and1004m are available. They m
21、ay be used with test portions of about2g. 5.3 Adjustable-height supports 5.4 Crystallization vessels, made of glass, diameter approximately125mm, height approximately65mm. 5.5 Funnel, made of polyethylene, diameter about90mm. 5.6 Vacuum device 5.7 Ultrasonic cleaner, (maximum power:100W). 5.8 Electr
22、ic oven, capable of being controlled at110 2 C. 5.9 Desiccator, containing activated alumina or other suitable desiccant. 6 Procedure 6.1 Test portion Depending on the sizes of the sieve apertures, weigh, to the nearest0,0001g, the following masses of the sample, which have been taken in accordance
23、with ISO802: 2 g for the63and454m sieves; 1 g for the324m sieve; 0,4 g for the164m sieve. NOTEIf the determination is carried out on a previously dried test portion, determine on a second test portion of mass equal to that taken for the determination, the “conventional moisture” at300 C, as specifie
24、d in ISO803. In this case, the final drying should be carried out at300 C. It is necessary to use a second test portion in order to avoid any alteration of the primary granulometric composition (i.e., on the test portion as such). 6.2 Determination Weigh the sieves to the nearest0,0001g. Fit each si
25、eve on one of the supporting arms of the agitation device (5.1), with the cam in the upper position Place the crystallization vessels (5.4) on the adjustable-height supports (5.3) just below the sieves. Pour into the crystallization vessel an amount of the sodium metaphosphate solution (4.1) suffici
26、ent to touch the lower rim of each sieve. Add4 or5 drops of the surface active agent(4.2). Transfer the test portions into the sieves and start the agitation device.BS4140-24:1987 2 BSI 11-1999 If the alumina agglomerates, break up the lumps using a fine jet of water. Collect the alumina from time t
27、o time in the middle of the sieve using a jet of water. After15min, stop the agitation, change the dispersing solution in the crystallization vessels and agitate again for15min. Repeat the change of dispersion solution and agitation until no further alumina passes through the sieve. Fit the sieves o
28、nto the funnel (5.5), placed on the vacuum device (5.6), and remove the water. Wash both sieve and residue several times with water. Dry the sieves with their contents in the electric oven (5.8), controlled at110 2 C, for at least1h. Weigh the sieve and residue to the nearest0,0001g, after allowing
29、to cool in the desiccator (5.9). 7 Expression of results The particle size fraction passing through each sieve, expressed as a percentage by mass, is given by the formula where NOTEThe precision parameters are under study and will be added later. 8 Cleaning of the sieves Carefully remove the residua
30、l alumina from the sieve using a soft bristle-brush. Immerse the sieve in the water contained in the tank of the ultrasonic cleaner (5.7). Start the cleaner and allow it to run for2min. Wash the sieve with water and dry it in the electric oven (5.8), controlled at110 2 C. NOTEIt is important to exam
31、ine the condition of the electroformed membrane microscopically. The membrane should be clean and completely free. Otherwise, it should be replaced. 9 Test report The test report shall include the following particulars: a) an identification of the sample; b) the reference of the method used (square-
32、aperture or round-aperture sieves); c) the results and the method of expression used; d) any unusual features noted during the determination; e) any operations not included in this International Standard or in the International Standard to which reference is made, or regarded as optional. m 0 is the
33、 mass, in grams, of the test portion; m 1 is the mass, in grams, of the empty sieve; m 2 is the mass, in grams, of the sieve with the residue. 100 m 2 m 1 m 0 -100 BS4140-24:1987 BSI 11-1999 3 Figure Typical agitation device for electroformed sieves4 blankBS4140-24:1987 BSI 11-1999 Publications refe
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