1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 12948:2010Liming materials Determination of sizedistribution by dry and wetsievingBS EN 12948:2010 BRITISH STANDARDNational forewordThis British Standard is the UK implemen
2、tation of EN 12948:2010. Itsupersedes BS EN 12948:2002 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CII/37, Fertilisers and related chemicals.A list of organizations represented on this committee can beobtained on request to its secretary.This public
3、ation does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2010ISBN 978 0 580 63902 9ICS 65.080Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authori
4、ty of theStandards Policy and Strategy Committee on 30 November 2010.Amendments issued since publicationDate Text affectedBS EN 12948:2010EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12948 November 2010 ICS 65.080 Supersedes EN 12948:2002English Version Liming materials - Determination of si
5、ze distribution by dry and wet sieving Amendements minraux basiques - Dtermination de la distribution granulomtrique par tamisage par voie sche ou par voie humide Calcium-/Magnesium-Bodenverbesserungsmittel - Bestimmung der Korngrenverteilung durch Trocken- und Nasssiebung This European Standard was
6、 approved by CEN on 2 October 2010. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nat
7、ional standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and
8、 notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
9、Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All
10、 rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12948:2010: EBS EN 12948:2010EN 12948:2010 (E) 2 Contents Page Foreword 3Introduction .41 Scope 52 Normative references 53 Principle 54 Apparatus .55 Sampling and sample preparation .66 Proc
11、edure .67 Expression of results 88 Precision .99 Test report 9Annex A (informative) Results of an inter-laboratory trial to determine the size distribution by dry and wet sieving. 10Bibliography . 11BS EN 12948:2010EN 12948:2010 (E) 3 Foreword This document (EN 12948:2010) has been prepared by Techn
12、ical Committee CEN/TC 260 “Fertilizers and liming materials”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2011, and conflicting national standards
13、shall be withdrawn at the latest by May 2011. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 12948:2002.
14、The following has been added to the former edition of the European Standard: a) the sampling method is not part of the standard. Informative reference to EN 1482-1 added; b) normative reference to EN 1482-2 concerning sample preparation added; c) clarification of the method of dispersion of agglomer
15、ates in method B added; d) Bibliography revised. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, F
16、rance, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. BS EN 12948:2010EN 12948:2010 (E) 4 Introduction The dry sieving of powdered material con
17、taining individual particles can be carried out quite easily. This method is simple, quick, cheap and enables the determination of the particle size of water-soluble materials. Therefore the dry sieving method should always be used first. However, the sieve apertures can become blocked by sample par
18、ticles, a phenomenon known as blinding. Blinding is mainly caused by caking and the production of electrostatic charges, particularly on sieves with small apertures. Dry sieving of very wet material can also lead to blinding. These difficulties are not encountered with the wet sieving method, which
19、is applicable to any kind of material such as powders (dry or wet), paste-like products or granules except those containing water-soluble constituents. In order to ensure the comparability of results, all masses of size fractions are expressed as dry matter. The approach to methods and principles of
20、 sieving refers to existing guidelines and European Regulations (1 and 2). BS EN 12948:2010EN 12948:2010 (E) 5 1 Scope This European Standard specifies two methods for the determination of the particle size distribution of liming materials. The dry sieving method (method A) is applicable to all limi
21、ng materials except wet and paste-like products. Method A is not applicable, if blinding, caking, electrostatic charges or agglomeration occur after pre drying. The wet sieving method (method B) is applicable to products which are susceptible to blinding, caking, electrostatic charges or agglomerati
22、on after pre drying. Method B can be used to determine the primary particle size distribution of granulated products. Method B is not applicable to burnt lime and liming materials containing water-soluble constituents. 2 Normative references The following referenced documents are indispensable for t
23、he 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. EN 1235:1995, Solid fertilizers Test sieving (ISO 8397:1988 modified) EN 1482-2, Fertilizers and liming mat
24、erials Sampling and sample preparation Part 2: Sample preparation EN 12048, Solid fertilizers and liming materials Determination of moisture content Gravimetric method by drying at (105 2) C (ISO 8190:1992 modified) ISO 565, Test sieves Metal wire cloth, perforated metal plate and electroformed shee
25、t Nominal sizes of openings ISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth 3 Principle 3.1 Method A Dry sieving of a liming material with one or more test sieves by hand or using a mechanical sieving machine. 3.2 Method B Wet sieving of a liming ma
26、terial, if necessary after dispersion under continuous water spraying, by hand or using a mechanical sieving machine. Drying of the different fractions retained on the sieves. 4 Apparatus Usual laboratory apparatus and in particular 4.1 to 4.6. 4.1 Balance, capable of weighing to the nearest 0,01 g.
27、 BS EN 12948:2010EN 12948:2010 (E) 6 4.2 Mechanical shaker (sieving machine), capable of imparting both horizontal and vertical motion to material inside a nest of sieves, fitted with a lid with a water intake and a receiver with a water outlet when used for method B. NOTE Hand sieving can be carrie
28、d out instead of mechanical sieving. 4.3 Stainless steel woven wire test sieves, conforming to ISO 3310-1 and of appropriate nominal aperture sizes. 4.4 Stopwatch. 4.5 Soft brush. 4.6 Oven, capable of being controlled at (105 2) C. 5 Sampling and sample preparation Sampling is not part of the method
29、 specified in this document. A recommended sampling method is given in EN 1482-1. Sample preparation shall be carried out in accordance with EN 1482-2. 6 Procedure 6.1 Test portion The whole laboratory sample shall be divided in equal test portions of at least 100 g. The size of the test portions wi
30、ll vary according to the coarseness of the laboratory sample and shall be in accordance with EN 1235:1995, Table 1, subject to a minimum of 100 g. 6.2 Method A 6.2.1 Preparation of test portions Dry wet samples if there is a possibility that blinding of the sieves could occur during the sieving. Dry
31、 the wet sample in an oven (4.6) at (105 2) C for an appropriate period of time (see EN 12048). Check whether agglomeration occurs after drying by carrying out a preliminary sieving test. Use method B if agglomeration occurs. 6.2.2 Determination WARNING When sieving burnt or hydrated lime products,
32、it is essential that precautions are taken to avoid inhalation and skin contact with the product. It is recommended that operations are carried out under a fume hood and appropriate gloves and eye protection are worn. 6.2.2.1 Carry out at least two single determinations on separate test portions pre
33、pared from the same laboratory sample. 6.2.2.2 Select a maximum of seven test sieves (4.3) from the range of principal sizes listed in ISO 565 to cover the range of particle size expected. For granular liming materials perforated plates according to ISO 3310-2 may be used. BS EN 12948:2010EN 12948:2
34、010 (E) 7 Assemble the sieves in ascending order of aperture size on top of the receiver. Weigh the test portion (6.1) to the nearest 0,01 g per 100 g of test portion, place it on the top sieve and fit the cover. 6.2.2.3 Place the sieve or the assembled nest of sieves on the mechanical shaker (4.2)
35、and shake for exactly 10 min (use a stopwatch (4.4). Set the mechanical shaker to a medium vibration frequency throughout the sieving. 6.2.2.4 If a nest of sieves is used, remove the sieves from the nest and weigh the quantity retained on each sieve and in the receiver to the nearest 0,01 g. Remove
36、particles caught in the mesh of the sieve by brushing the reverse side of the sieve. 6.2.2.5 If only one sieve is used, discard the undersize fraction that has passed through the sieve. Repeat the sieving process for exactly 1 min. If more than 0,2 g passes through the sieve, repeat the procedure as
37、 many times as necessary. Remove particles caught in the mesh of the sieve by brushing the reverse side of the sieve. Weigh the oversize fraction. 6.3 Method B 6.3.1 General Use an additional test portion to determine the moisture content in accordance with EN 12048. Carry out at least two single de
38、terminations on separate test portions prepared from the same laboratory sample. 6.3.2 Determination 6.3.2.1 Non-granulated and non-agglomerated products 6.3.2.1.1 Select a maximum of seven test sieves (4.3) from the range of principal sizes listed in ISO 565 to cover the range of particle size expe
39、cted. Assemble the sieves in ascending order of aperture size on top of the receiver. Weigh the test portion (6.1) to the nearest 0,01 g per 100 g of test portion, place it on the top sieve and fit the lid with the intake for water. 6.3.2.1.2 Place the assembled nest of sieves on the mechanical shak
40、er (4.2) and shake under a continuous water flow of 2,0 l/min to 2,5 l/min for exactly 10 min (use a stopwatch (4.4). Set the mechanical shaker to a medium vibration frequency throughout the sieving. 6.3.2.1.3 Remove the sieves from the mechanical shaker and rinse the residues of each sieve quantita
41、tively into separate 250 ml pre-weighed beakers. Decant or pipette most of the water on the top of the material, ensuring that no material is spilled. Dry each of the oversize fractions in an oven (4.6) at (105 2) C and then weigh each fraction separately (see EN 12048). 6.3.2.2 Granulated and agglo
42、merated products Weigh the test portion (6.1) to the nearest 0,01 g per 100 g of test portion and transfer it into a 800 ml beaker. BS EN 12948:2010EN 12948:2010 (E) 8 Add approximately 500 ml of water. Stir the granules for 10 min by means of a mechanical stirrer with a rotational speed not exceedi
43、ng 800 min-1. Avoid grinding. Rinse out the sample completely on to the top sieve and fit the lid with the intake for water. Continue according to 6.3.2.1.2 and 6.3.2.1.3. If the sum of individual masses is less than 95 % of the original mass, it should be assumed that the sample contains water-solu
44、ble constituents. 7 Expression of results 7.1 Method A 7.1.1 Record the masses of the fractions retained on the sieves and the receiver (see 6.2.2.4 and 6.2.2.5). 7.1.2 Calculate each mass fraction as a percentage of the mass of the test portion (see EN 1235:1995, Annex ZA) according to Equation (1)
45、. 1t,1001n,1,nmmw= (1) where wn,1 is the mass fraction retained on sieve n or in the receiver, in percent; mn,1is the mass retained on sieve n or in the receiver, in grams; mt,1is the mass of the test portion, in grams. 7.2 Method B 7.2.1 Record the masses of the fractions retained on the sieves (se
46、e 6.3.2.1.3). 7.2.2 Calculate each mass fraction as a percentage of the mass of the test portion (see EN 1235:1995, Annex ZA) according to Equation (2). 2t,1002n,2n,mmw= (2) where wn,2 is the mass fraction retained on sieve n, in percent; mn,2 is the mass retained on sieve n after drying, in grams;
47、mt,2is the mass of the test portion expressed on a dry matter basis (see EN 12048), in grams. BS EN 12948:2010EN 12948:2010 (E) 9 8 Precision 8.1 General The precision of the methods were established by an inter-laboratory trial carried out in 1999 in accordance with ISO 5725. The values obtained fo
48、r repeatability limit and reproducibility limit are expressed for the 95 % probability level and shall not be applicable to particle size ranges other than those given. NOTE The repeatability limits and reproducibility limits obtained from the inter-laboratory trial for each product being tested are
49、 given in Annex A. 8.2 Repeatability The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the same operator using the same equipment within the shortest feasible time interval will exceed the repeatability limit (r) on average not more than once in 20 cases in the normal and correct operation of the method. The values are: for method A: r = 6,50 % at a fineness of less than 1 mm; for metho
