1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Determination of attrition index ICS 71.100.10Aluminium oxide used for the production of primary al
2、uminium BRITISH STANDARDBS ISO 17500:2006BS ISO 17500:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2006 BSI 2006ISBN 0 580 48865 9Cross-referencesThe British Standards which implement international publications referred to in t
3、his document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a co
4、ntract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 9 and a ba
5、ck cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date Comments present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK int
6、erests informed; monitor related international and European developments and promulgate them in the UK.A list of organizations represented on this committee can be obtained on request to its secretary.National forewordThis British Standard reproduces verbatim ISO 17500:2006 and implements it as the
7、UK national standard. The UK participation in its preparation was entrusted to Technical Committee CII/24, Raw materials for the aluminium industry, which has the responsibility to: aid enquirers to understand the text;Reference numberISO 17500:2006(E)INTERNATIONAL STANDARD ISO17500First edition2006
8、-04-01Aluminium oxide used for the production of primary aluminium Determination of attrition index Oxyde daluminium utilis pour la production de laluminium primaire Dtermination de lindex dattrition BS ISO 17500:2006ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references .
9、 1 3 Principle. 1 4 Apparatus 1 5 Sample handling and preparation. 3 5.1 Reference alumina 3 5.2 Test sample . 3 6 Procedure 3 6.1 Flow calibration. 3 6.2 Attrition procedure for test sample and reference alumina . 6 6.3 Particle size distribution analysis . 6 7 Calculation and reporting of results
10、. 6 8 Precision 7 9 Quality control. 7 10 Test report . 7 Annex A (informative) Results of test programme . 8 Bibliography . 9 BS ISO 17500:2006iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of
11、 preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental
12、, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main
13、task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Atten
14、tion is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 17500 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary aluminiu
15、m. BS ISO 17500:2006vIntroduction This International Standard is based on Australian method, AS 2879.10-2003, Alumina Determination of attrition index. The Attrition Index reference material ASCRM 025 was released in December 2003 by SAI Global, along with a Technical Report on its preparation (TR 2
16、.25-2003). These are available from SAI through their website: http:/.au/ BS ISO 17500:2006blank1Aluminium oxide used for the production of primary aluminium Determination of attrition index 1 Scope This International Standard specifies a procedure for the determination of the attrition index of sme
17、lter-grade alumina. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 29
18、26:2005, Aluminium oxide used for the production of primary aluminium Particle size analysis for the range 45 m to 150 m Method using electroformed sieves AS 2879.6-1995, Alumina Determination of the mass distribution of particle sizes using electroformed sieves 3 Principle A test portion is attrite
19、d using a high velocity gas jet under controlled conditions using the attrition index apparatus. Flow in the apparatus is calibrated to a reference alumina. The particle size distribution is measured before and after attrition. The attrition index is the relative percentage decrease in the + 45 m fr
20、action under specific test conditions. 4 Apparatus 4.1 Attrition index apparatus. A typical assembled apparatus is shown in Figure 1 which consists of: a) Column Stainless steel, aluminium and glass columns of length 1 500 mm to 1 600 mm and inside diameter 25 mm have been tested and found to be sui
21、table. To minimize dust carryover, columns with larger-diameter upper sections are also suitable. A column of reduced overall length (700 mm) and upper diameter 64 mm has also been found to be suitable. In any case, modified columns shall maintain the 25 mm ID for a minimum of 200 mm from the orific
22、e plate. Also, they shall be constructed with a smooth tapered transition between sections, to ensure that alumina is not held up in the upper section of the column. Columns may also be provided with a timed automated rapper to facilitate rapping the column see 6.2 f). BS ISO 17500:20062 b) Orifice
23、plate and assembly The orifice plate assembly holds and seals the orifice plate 1)centrally to the base of the column. The orifice plate has a circular aperture of (400 15) m diameter cut through a hard material. A typical orifice plate and its correct orientation is shown in Figure 2. Flow variatio
24、ns caused by minor dimensional variations between orifice plates are overcome by calibration with a reference alumina. c) Dust filter and assembly The dust filter assembly holds and seals the dust filter to the top of the column. Ideally the assembly should enclose the filter to allow subsequent flo
25、w measurement to the atmosphere, so that the flow can be monitored to ensure that it is maintained for the test period. NOTE A cellulose Soxhlet thimble, with an internal diameter of 43 mm and length of 123 mm, has been found to be a suitable filter. d) Flow measurement and control equipment The flo
26、w measurement and control equipment shall include components to measure and control the airflow, to within 0,1 l/min, at the operating flows (typically 5 l/min to 8 l/min). 4.2 Balance. Analytical balance capable of weighing 100 g to the nearest 0,01 g. 4.3 Particle sizing apparatus. Electroformed s
27、ieves and apparatus as specified in ISO 2926:2005. For an alternative sizing technique, see Note to 6.3. 4.4 Sample splitter. To provide representative portions, a rotary splitter is preferred. 4.5 Dried air or nitrogen supply. A regulated system capable of supplying stable pressures, typically in t
28、he range 400 kPa to 800 kPa. 4.6 Sample containers. Capable of being sealed and with a volume of between 60 ml and 125 ml. 4.7 Reference alumina. With a certified attrition index value. NOTE A suitable reference material is available from Standards Australia (ASCRM 025 series). 1) A suitable orifice
29、 plate is obtainable from Societe des Filieres Balloffet, 13 rue de lIndustrie, BP 18, 01151 Lagnieu Cedex, France. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of the product named. Equivalent products may be use
30、d if they can be shown to lead to the same results. BS ISO 17500:200635 Sample handling and preparation 5.1 Reference alumina The reference alumina shall be split into 50 g to 60 g portions for attrition index and particle size analysis. 5.2 Test sample The test sample shall be equilibrated to the l
31、aboratory atmosphere for a minimum of 2 h in a layer of maximum thickness 5 mm. Then the sample shall be split into 50 g to 60 g portions for attrition index and particle size analysis. Immediately after splitting, place the sample in containers (4.6) and seal. 6 Procedure 6.1 Flow calibration The c
32、alibrated flow rate (Fc) required to produce the reference attrition index value shall be determined using several portions of reference alumina. Foshall be subsequently used for the analysis of test samples. The procedure to determine Foshall be as follows: a) Determine the percent + 45 m size frac
33、tion of the unattrited reference alumina in accordance with 6.3. Perform this determination in triplicate. The mean of the three determinations is used in the calculation of the attrition index for all calibration portions. b) Weigh out six 50 g 0,5 g portions of the reference alumina, using the bal
34、ance (4.2), and record the actual mass to the nearest 0,01 g (m1). c) Attrite the first of the six portions of the reference alumina in accordance with 6.2 c) to i), and determine the percent + 45 m size fraction of the attrited material. Use a nominal exit flow rate within the range of 5 l/min to 8
35、 l/min. d) Calculate the attrition index of this first portion of reference alumina according to Clause 7. e) Using this initial result, attrite three further portions of the reference alumina at different flow rates, determine the percent + 45 m size fraction of each portion and calculate each port
36、ions attrition index. Choose these flow rates such that: 1) the determined attrition index values are greater and less than the recommended reference value; and 2) the difference between the minimum and maximum flow rate is at least 1,0 l/min, but less than 3,0 l/min. f) Plot attrition index versus
37、flow rate for these four portions and include a linear trend line of best fit. Add y-axis error bars of 5 % relative to the data points. If an error bar for a data point does not cross the trend line then repeat the analysis for that flow rate. Use the chart to determine the calibrated flow rate (Fc
38、) required to obtain the attrition index of the reference alumina. Figure 3 shows an example of a typical calibration. NOTE The attrition index has been shown not to be a linear function of flow, however linearity is assumed for the narrow range of flow rates used for calibration. g) Using the remai
39、ning two portions, repeat the attrition procedure 6.2 c) to i) in duplicate at the calibrated flow rate. Determine the percent + 45 m size fraction of each portion and calculate each portions attrition index. The average of these results should produce the reference attrition index value 0,8. If thi
40、s value is not obtained, then the apparatus shall be checked and the calibration repeated. BS ISO 17500:20064 NOTE The 0,8 precision above is derived from (2)r , i.e. the repeatability of the method (see Table 1) as applied to duplicates. Dimensions in millimetres Key 1 dust-filter assembly 2 flow m
41、eter 3 atmosphere 4 optional expanded diameter to minimise dust carry-over, reduce overall height 5 orifice plate assembly 6 on/off valve 7 dry compressed air or nitrogen 8 flow-control valve 9 inlet air-pressure gauge 10 rapper 11 timer NOTE The automatic rapper is optional. Figure 1 Typical attrit
42、ion apparatus BS ISO 17500:20065Dimensions in millimetres Key 1 top 2 epoxy 3 diamond orifice 4 mount 5 bottom 6 plug NOTE 1 Mount and plug: stainless steel 40 mm 6 mm. NOTE 2 Orifice: 0,400 mm 2 m (as supplied by Balloffet) laser drilled in natural diamond. Figure 2 Typical orifice plate Key X flow
43、 rate (l/min) Y attrition index 1 reference value 2 calibrated flow rate (Fc) Figure 3 Attrition index of reference material versus flow rate BS ISO 17500:20066 6.2 Attrition procedure for test sample and reference alumina The attrition procedure shall be carried out as follows. a) Determine the per
44、cent + 45 m content of an unattrited sample portion using the method described in 6.3. b) Weigh out 50 g 0,5 g of the alumina, using the balance (4.2), and record the actual mass to the nearest 0,01 g (m1). c) Set up the attrition apparatus without the dust-collector assembly. d) Using a funnel, slo
45、wly transfer this portion into the attrition tube, minimizing dust loss. Re-install the dust-collector assembly. e) Activate the air supply, set the flow rate and start the timer. The flow rate, when determining Fousing the reference alumina, shall be as described in 6.1 c) and e), and for test samp
46、les shall be the calibrated flow rate (Fo). The flow rate shall be maintained within 0,1 l/min of the set rate for the duration of the test. f) Rap the column at least every 3 min to dislodge alumina adhering to the column. NOTE An optional automatic timed rapping device can be attached to the colum
47、n. After exactly 15 min, turn off the air supply, and stop the timer. g) Quantitatively transfer the contents of the dust collector and the attrition tube to a tared sample container (4.6). Remove any material from the inside of the apparatus and add to the container. h) Determine the total mass of
48、the material recovered to 0,01 g. See next paragraph if this mass is more than 0,5 g different from the initial mass (m1). The recovered mass will typically be less than the initial mass (m1) due to loss of moisture. Typically, this loss of mass will be less than 0,5 g, but for samples with a high i
49、nitial moisture content, this loss may be considerably higher. Care should be taken to ensure that the loss of mass is not due to loss of fines or incomplete recovery of material from the apparatus. i) Determine the percent + 45 m content after attrition, using the same method for the unattrited sample in 6.3. If the sizing procedure requires sub-sampling, the attrited material shall first be homogenized by passing through a sieve of aperture 200 m to 500 m (to b
