1、BRITISH STANDARD BS ISO 13318-3:2004 Incorporating corrigendum no. 1 Determination of particle size distribution by centrifugal liquid sedimentation methods Part 3: Centrifugal X-ray method ICS 19.120 BS ISO 13318-3:2004 This British Standard was published under the authority of the Standards Policy
2、 and Strategy Committee on 9 August 2004 BSI 2007 ISBN 978 0 580 60045 6 National foreword This British Standard is the UK implementation of ISO 13318-3:2004. Together with BS ISO 13318-1:2001 and BS ISO 13318-2:2001, it supersedes BS 3406-6:1985 which is withdrawn. The UK participation in its prepa
3、ration was entrusted by Technical Committee LBI/37, Sieves, screens and particle sizing, to Subcommittee LBI/37/4, Sizing by methods other than sieving. A list of organizations represented on this subcommittee can be obtained on request to its secretary. This publication does not purport to include
4、all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. Date Comments 17356 Corrigendum No. 1 31 August 2007 Addition of supersession
5、details Reference number ISO 13318-3:2004(E)INTERNATIONAL STANDARD ISO 13318-3 First edition 2004-07-15 Determination of particle size distribution by centrifugal liquid sedimentation methods Part 3: Centrifugal X-ray method Dtermination de la distribution granulomtrique par les mthodes de sdimentat
6、ion centrifuge dans un liquide Partie 3: Mthode centrifuge aux rayons X BSISO133183:2004ii ISO 13318-3:2004(E) iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Normative references . 1 3 Terms and definitions. 1 4 Symbols . 1 5 Sampling 2 6 Principle . 2 7 Apparatus. 3 8 Preparation 4 9 Measu
7、rement procedure 4 10 Tests in duplicate and validation 4 11 Calculation of results 5 12 Test report 5 Annex A (informative) Worked example. 6 BSISO133183:2004ISO 13318-3:2004(E) iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodi
8、es (ISO member bodies). The work of 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
9、, governmental and non-governmental, 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 IS
10、O/IEC Directives, Part 2. The main 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
11、member bodies casting a vote. Attention 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 13318-3 was prepared by Technical Committee ISO/TC 24, Sieves, siev
12、ing and other sizing methods, Subcommittee SC 4, Sizing by methods other than sieving. ISO 13318 consists of the following parts, under the general title Determination of particle size distribution by centrifugal liquid sedimentation methods: Part 1: General principles and guidelines Part 2: Photoce
13、ntrifuge method Part 3: Centrifugal X-ray method BSISO133183:2004ISO 13318-3:2004(E) vIntroduction The X-ray centrifuge monitors particle concentration changes at a fixed or variable radius. In some configurations, the instrument can also be used in a gravitational mode (see ISO 13317-1) and those d
14、ata blended with other data determined in the centrifugal mode, thus extending the typical upper size limit above 5 m. BSISO133183:2004blankINTENRATIONAL TSANDADR IS-81331 O3:(4002E)1Determination of particle size distribution by centrifugal liquid sedimentation methods Part 3: Centrifugal X-ray met
15、hod WARNING This part of ISO 13318 may involve hazardous materials operations and equipment. This part of ISO 13318 does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practic
16、es and determine the applicability of the regulatory limitations prior to its use. 1 Scope This part of ISO 13318 describes a method for determining the particle size distribution of homogeneous particulate material using centrifugal sedimentation in a liquid. Solids concentrations are determined by
17、 the attenuation of an X-ray beam. The resulting signal enables conversion to a particle size distribution. The method of determining the particle size distribution described in this standard is applicable to powders which can be dispersed in liquids or powders which are present in slurry form. The
18、typical particle size range for analysis is from 0,1 m to 5 m. The method is applicable to powders in which all particles have the same effective density, chemical composition and comparable shapes. Materials possessing elements with an atomic number greater than about 12 can be expected to produce
19、adequate X-ray opacity. Particles should not undergo chemical or physical change in the suspension liquid. It is necessary that the particles have a higher density than that of the liquid. 2 Normative references The following referenced documents are indispensable for the application of this documen
20、t. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 13318-1, Determination of particle size distribution by centrifugal liquid sedimentation methods Part 1: General principles and guide
21、lines 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 13318-1 and the following apply. 4 Symbols For the purpose of this document, the symbols of ISO 13318-1 and the following apply. B function of the atomic number of the sample elements in the beam
22、C concentration of sample in the beam l 0transmission of the emergent X-ray beam through the suspending fluid with no particles present l transmission of the emergent X-ray beam through suspension at radius M and time t BSISO133183:2004ISO 13318-3:2004(E) 2 D X-ray density log 10(l 0 /l) x Stdiamete
23、r of the largest particle in the X-ray beam, i.e. the Stokes diameter, expressed in micrometres M distance, expressed in centimetres, from rotation axis to measurement zone S distance, expressed in centimetres, from rotation axis to liquid-air interface of sample 5 Sampling For information regarding
24、 sampling, see ISO 13318-1. 6 Principle A stable, finely collimated beam of X-rays passes through a suspension containing the sample particles and is detected at a known radius. The centrifuge disc containing the sample is of known dimensions and a known amount of suspension is used so that the surf
25、ace radius for the suspension can be calculated. The measured settling radius can be reduced during the analysis for the purpose of obtaining a more rapid analysis than would be possible if the radius were fixed. The mass percentage of sample present at a given time, and at a known measurement radiu
26、s, is determined by calculating the ratio of the X-ray transmission through a clear dispersing liquid, and the signal with the sample present. The Stokes diameter (x St ) at measurement radius, M, and time, t, is given by the following equation: () St 2 s1 18 In M S x t = (1) The transmission, l, of
27、 the emergent X-ray beam having passed through the suspension is proportional to the mass of powder in the beam. 0 exp ( , ) ll B C r t = (2) where C(r,t) is the concentration of the sample in the beam at radius, r, and time, t. The X-ray density, D, at measurement radius, r, and time, t, is given b
28、y the following equation: ( ) ( ) 10 10 0 , log e log / D BC M t l l = = (3) The X-ray density of the emergent beam, after correction for radial dilution effects, is proportional to the mass of sample in the beam. BSISO133183:2004ISO 13318-3:2004(E) 37 Apparatus 7.1 Basic apparatus The instrument (F
29、igure 1) consists typically of a shallow bowl-shaped X-ray-transparent disc of known internal radius and depth. The bowl is mounted vertically on the shaft of an electric motor with a variable speed, typically between 500 rmin 1and 15 000 rmin 1 . An X-ray source and detector assembly, which may als
30、o scan radially, measures transmission through the suspension as a function of time and radial position. Software provides for the conversion of data directly into frequency distributions in the form of tables or graphs of cumulative mass percentage versus particle size. Key 1 arm display 8 motor 15
31、 power supply 2 signal display 9 detector 16 signal cond. 3 rotational motion (rmin 1 ) 10 suspension 17 colour monitor 4 instrument keyboard and display 11 cell 18 computer data system program 5 central processing unit 12 X-ray source 19 data analysis, archiving comparison 6 analog digital converte
32、r 13 power supply and beam control 20 plotter 7 motor control and power supply 14 scanning system 21 printer aParameter and data transfer. Figure 1 Line diagram of an X-ray scanning disc centrifuge BSISO133183:2004ISO 13318-3:2004(E) 4 7.2 Ancillary apparatus The ancillary apparatus consists of disp
33、ersing vessel, of appropriate dimensions, flexible spatula, and ultrasonic bath or probe, a bottle shaker or high speed mechanical stirrer capable of rotating at 500 rmin 1to 1 000 rmin 1 . 8 Preparation 8.1 Sample preparation Prepare an analytical sample as described in ISO 13318-1. Prepare an init
34、ial sample for analysis having a homogeneous concentration of about 0,2 % by volume. If this is not sufficient to give an adequate signal, it may be necessary to increase the concentration. Carry out duplicate tests at higher concentrations in order to determine whether delayed settling is occurring
35、. If the second test gives a significantly higher percentage of small particles, then discard these data. 8.2 Temperature Measure and record the temperature of the suspension before and after analysis, in accordance with ISO 13318-1. Record the liquid viscosity and liquid density for the spin fluid
36、or suspension at the temperature of the analysis. Maintain the temperature in accordance with ISO 13318-1. 8.3 Dispersion For information regarding the dispersion, see ISO 13318-1. 9 Measurement procedure Switch the instrument on 20 min before use in order to obtain stable operating signal. Determin
37、e the attenuation of the emergent X-ray beam with only the suspension liquid in the disc. To this end, inject sufficient clear suspension liquid into the disc to ensure that the X-ray beam path is below the liquid surface in order to provide the maximum X-ray transmission reading. The suspension liq
38、uid is then removed. For more precise results, a base-line scan of the entire measuring portion of the disc may be determined for subsequent correction of the corresponding suspension data. Set the run conditions prior to analysis by keying into the computer the operating variables such as effective
39、 particle density, liquid density and liquid viscosity. Then switch the centrifuge on to the desired speed and feed the suspension into the centrifuge disc without delay and activate the timer. 10 Tests in duplicate and validation 10.1 Tests in duplicate For information regarding duplicate tests, se
40、e ISO 13318-1. 10.2 Validation For information regarding validation, see ISO 13318-1. BSISO133183:2004ISO 13318-3:2004(E) 511 Calculation of results 11.1 Calculation of particle size Calculate the Stokes diameters in accordance with ISO 13318-1. 11.2 Calculation of cumulative mass percentage In the
41、centrifugal X-ray method, the attenuation of the X-ray beam is directly proportional to the mass of particles in the path of the beam through the suspension and the result is presented automatically. 12 Test report The report shall conform with the requirements in accordance with ISO 13318-1. Result
42、s shall typically be presented as a plot of Stokes diameter versus cumulative distribution by mass reported to the nearest 0,1 %. On graphic presentations of the plot, the diameters are placed on the abscissa and the cumulative mass percentage on the ordinate. The report shall include reference to t
43、his part of ISO 13318, name of the testing establishment, date of the test, operator identification, instrument type used, mode of operation (e.g. fixed radius or scanning), test sample identification, sample density (and mass, if available), suspending liquid, its temperature, density, viscosity an
44、d, if applicable, its volume, dispersing agent and concentration of agent used, method of dispersion of the suspension, including dispersion time, centrifuge speed, any other operations not specified in this part of ISO 13318 and which might have an influence on the results. The following instrument
45、 characteristic, typically determined by the manufacturer and pre-programmed into the equipment software, may be optionally reported if available: Measurement radius, M (not fixed in scanning mode) BSISO133183:2004ISO 13318-3:2004(E) 6 Annex A (informative) Worked example A.1 General Experimental da
46、ta are presented in Table A.1. Supplementary data include the following. The measurement radius, M, at the start of the analysis is 4,88 cm and the surface radius, S, is 4,41 cm. After 1 min, the source and detector scan towards the surface at constant speed and M decreases as t increases such that
47、after 7 min scanning the X-ray beam is 0,2 cm below the surface. The opacity to X-ray is determined by the count level of a scintillation counter and converted into a percentage to give the measured concentration. The example data presented here represent smoothed data taken every 15 s. In an actual
48、 analysis, the data may be taken more frequently and data smoothing may be performed automatically in some instrument configurations. Using Equation (1), the Stokes diameter, x 1 , in micrometres, at 15 s is given by 4 1 2 4,88 18 8,90 10 In 4, 41 1, 7 1 (2 500 1000) 15(50 ) x = (A.1) At 1 min, the
49、Stokes diameter is 0,855 m. Scanning commences after 1 min and causes the measurement radius to decrease with increasing time. Subsequent diameters, expressed in micrometres, are, therefore, determined using the Stokes equation in the following form: i i In 4, 41 20,80 i M x t = (A.2) A.2 Example ISO reference ISO 13318-3 Testing establishment MAL Date 2000-
