1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 15921:2011Fertilizers Extraction ofsoluble phosphorus accordingto Petermann at 65 CBS EN 15921:2011 BRITISH STANDARDNational forewordThis British Standard is the UK impleme
2、ntation of EN 15921:2011. Itsupersedes DD CEN/TS 15921:2009 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CII/37, Fertilisers and related chemicals.A list of organizations represented on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 p
3、ublication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 72727 6ICS 65.080Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the au
4、thority of theStandards Policy and Strategy Committee on 30 June 2011.Amendments issued since publicationDate Text affectedBS EN 15921:2011EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 15921 June 2011 ICS 65.080 Supersedes CEN/TS 15921:2009English Version Fertilizers - Extraction of soluble p
5、hosphorus according to Petermann at 65 C Engrais - Extraction du phosphore soluble selon Petermann 65 C Dngemittel - Extraktion des lslichen Phosphors nach Petermann bei 65 C This European Standard was approved by CEN on 29 April 2011. CEN members are bound to comply with the CEN/CENELEC Internal Re
6、gulations 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 national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN me
7、mber. 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 notified to the CEN-CENELEC Management Centre has the same status as the official versions.
8、 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, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Sloveni
9、a, 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 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN nati
10、onal Members. Ref. No. EN 15921:2011: EBS EN 15921:2011EN 15921:2011 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Principle 4 5 Sampling .4 6 Reagents .5 7 Apparatus .6 8 Procedure .6 Bibliography 7 BS EN 15921:2011EN 15921:2011 (E) 3 Foreword This d
11、ocument (EN 15921:2011) has been prepared by Technical 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 lates
12、t by December 2011, and conflicting national standards shall be withdrawn at the latest by December 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
13、such patent rights. This document supersedes CEN/TS 15921:2009. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following co
14、untries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Sl
15、ovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 15921:2011EN 15921:2011 (E) 4 1 Scope This document specifies the procedure for the determination of soluble phosphorus in alkaline ammonium citrate. The method is applicable exclusively to precipitated dehydrated dicalcium phosphate (
16、CaHPO4. 2H2O). 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. EN 1482-2,
17、Fertilizers and liming materials Sampling and sample preparation Part 2: Sample preparation EN 12944-1:1999, Fertilizers and liming materials and soil improvers Vocabulary Part 1: General terms EN 12944-2:1999, Fertilizers and liming materials and soil improvers Vocabulary Part 2: Terms relating to
18、fertilizers EN 15475, Fertilizers Determination of ammoniacal nitrogen CEN/TS 15959, Fertilizers Determination of extracted phosphorus 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12944-1:1999 and EN 12944-2:1999 apply. 4 Principle Extraction of ph
19、osphorus from the test portion at a temperature of 65 C with an alkaline solution of ammonium citrate (Petermanns solution) under the specified conditions. 5 Sampling Sampling is not part of the method specified in this document. A recommended sampling method is given in EN 1482-1. Sample preparatio
20、n shall be carried out in accordance with EN 1482-2. Grinding of the laboratory sample is recommended for homogeneity reasons. BS EN 15921:2011EN 15921:2011 (E) 5 6 Reagents 6.1 Water, distilled or demineralized having the same characteristics as distilled water. 6.2 Petermanns solution 6.2.1 Charac
21、teristics of the Petermanns solution citric acid (C6H8O7. H2O): 173 g/l; ammonia: 42 g/l of ammoniacal nitrogen; pH between 9,4 and 9,7. 6.2.2 Preparation from diammonium citrate Dissolve 931 g of diammonium citrate (molecular mass 226,19) in about 3 500 ml of water (6.1), in a 5 l standard flask. S
22、tand in a bath of running water, mix and cool and add in small amounts ammonia. For example, for d20= 0, 906 g/ml corresponding to a level of 20,81 % by mass of ammoniacal nitrogen, it is necessary to use 502 ml of ammonia solution. Adjust the temperature to 20 C, make up to volume with water (6.1)
23、and mix. 6.2.3 Preparation from citric acid and ammonia Dissolve 865 g of citric acid monohydrate in about 2 500 ml of water (6.1) in a container of about 5 l capacity. Place the container in an ice bath, and add in small amounts, shaking constantly, ammonia solution using a funnel, the stem of whic
24、h is immersed in the citric acid solution. For example, for d20= 0, 906 g/ml corresponding to a level of 20,81 % by mass of ammoniacal nitrogen, it is necessary to add 1 114 ml of ammonia solution. Adjust the temperature to 20 C, transfer to a 5 l standard flask, make up to the mark with water (6.1)
25、 and mix. 6.2.4 Checking of the ammoniacal nitrogen content Transfer 25 ml of the solution into a 250 ml standard flask and make up to volume with water (6.1) and mix. Determine the ammoniacal content on 25 ml of this solution according to EN 15475. If the solution is correct, an amount of 15 ml of
26、c = 0,25 mol/l H2SO4 shall be used. If the strength of ammoniacal nitrogen is greater than 42 g/l, NH3can be expelled by a stream of inert gas or by moderate heating to bring back the pH to 9,7. Carry out a second determination. If the strength of ammoniacal nitrogen is less than 42 g/l, it will be
27、necessary to add a mass M in grams of ammonia solution: 20,815002,8)(42 = nM (1) n is the volume of the sulfuric acid c=0,25 mol/l, in millilitres or a volume, V, at 20 C: 0,906MV = (2) If V is less than 25 ml, add it directly to the 5 l flask with a mass of V 0,173 g powdered citric acid. BS EN 159
28、21:2011EN 15921:2011 (E) 6 If V is greater than 25 ml, it will be convenient to prepare a new litre of reagent in the following way. Weigh 173 g of citric acid. Dissolve it in 500 ml of water. And, taking the precautions indicated, add not more than 225 + V 1 206 ml of ammonia solution which was use
29、d to prepare the 5 l of reagent. Make up to volume with water and mix. Mix this volume of 1 l with the 4 975 ml previously prepared. 7 Apparatus 7.1 Common laboratory equipment and glassware, in particular equipment according to 7.2 to 7.4. 7.2 Water bath, which can be maintained at a temperature of
30、 (65 1) C. 7.3 500 ml graduated flask, e.g. Stohmann. 7.4 Dry fluted filter paper, free from phosphates. 8 Procedure 8.1 Test portion Weigh, to the nearest 0,001 g, 1 g of the prepared laboratory sample and transfer it to the graduated flask (7.3). 8.2 Extraction Add 200 ml of alkaline ammonium citr
31、ate solution (6.2). Stopper the flask and shake vigorously by hand to avoid the formation of lumps and to prevent any adherence of the substance to the sides. Place the flask in the water bath set at 65 C (7.2) and shake every 5 min during the first 0,5 h. After each shaking, raise the stopper to eq
32、uilibrate the pressure. The level of water in the water bath ought to be above the level of solution in the flask. Allow the flask to remain in the water bath a further 1 h at 65 C and shake every 10 min. Remove the flask, cool to a temperature of about 20 C, make up to a volume of 500 ml with water
33、. Mix and filter through a dry fluted filter paper (7.4), rejecting the first portion of filtrate. Continue the filtering until a sufficient quantity of filtrate is obtained to carry out the phosphorus determination according to CEN/TS 15959. BS EN 15921:2011EN 15921:2011 (E) 7 Bibliography 1 EN 148
34、2-1, Fertilizers and liming materials Sampling and sample preparation Part 1: Sampling 2 Regulation (EC) No 2003/2003 of the European Parliament and of the Council of 13 October 2003 relating to fertilisers, Official Journal L 304, 21/11/2003, P. 0001-0194, Annex IV, method 3.1.5.1 This page deliber
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