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1、DD CEN/TS 15750:2006 ICS 65.080, NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW DRAFT FOR DEVELOPMENT Fertilizers Determination of different forms of nitrogen in fertilizers containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods Licensed Cop
2、y: London South Bank University, South Bank University, 02/02/2009 05:59, Uncontrolled Copy, (c) BSI This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 31 January 2009 BSI 2009 ISBN 978 0 580 60740 0 Amendments/corrigenda issued since publi
3、cation DateComments DD CEN/TS 15750:2006 National foreword This Draft for Development is the UK implementation of CEN/TS 15750:2006. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development series of publications and is of a provisional nature. It
4、 should be applied on this provisional basis, so that information and experience of its practical application can be obtained. Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the international organization responsible for its convers
5、ion to an international standard. A review of this publication will be initiated not later than 3 years after its publication by the international organization so that a decision can be taken on its status. Notification of the start of the review period will be made in an announcement in the appropr
6、iate issue of Update Standards. According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into an international Standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent
7、to the Secretary of the responsible BSI Technical Committee at British Standards House, 389 Chiswick High Road, London W4 4AL. The UK participation in its preparation was entrusted to Technical Committee CII/37, Fertilisers and related chemicals. A list of organizations represented on this committee
8、 can be obtained on request to its secretary. This publication does not purport to include 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. Licensed Copy: London South Bank
9、 University, South Bank University, 02/02/2009 05:59, Uncontrolled Copy, (c) BSI DD CEN/TS 15750:2006 TECHNICAL SPECIFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZIFIKATION CEN/TS 15750 August 2008 ICS 65.080 English Version Fertilizers - Determination of different forms of nitrogen in fertilizers
10、containing nitrogen only as nitric, ammoniacal and urea nitrogen by two different methods Engrais - Dtermination des teneurs des diffrentes formes dazote en prsence les unes des autres dans les engrais ne contenant lazote que sous forme nitrique, ammoniacale et urique en utilisant deux mthodes diffr
11、entes Dngemittel - Bestimmung von Gesamtstickstoff in Dngemitteln mit Stickstoff in Form von Ammonium, Nitrat und Harnstoff unter Anwendung von zwei verschiedenen Verfahren This Technical Specification (CEN/TS) was approved by CEN on 11 May 2008 for provisional application. The period of validity of
12、 this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard. CEN members are required to announce the existence of this CEN/TS in the same wa
13、y as for an EN and to make the CEN/TS available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached. CEN members are
14、 the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzer
15、land and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2008 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. C
16、EN/TS 15750:2008: E Licensed Copy: London South Bank University, South Bank University, 02/02/2009 05:59, Uncontrolled Copy, (c) BSI DD CEN/TS 15750:2006 CEN/TS 15750:2008 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references4 3 Terms and definitions .4 4 Principle4 5 Sampling and sample pr
17、eparation.5 6 Method A.5 7 Method B.11 8 Precision of methods A and B13 9 Test report14 Annex A (informative) Statistical results of the inter-laboratory tests 15 Bibliography16 Licensed Copy: London South Bank University, South Bank University, 02/02/2009 05:59, Uncontrolled Copy, (c) BSI DD CEN/TS
18、 15750:2006 CEN/TS 15750:2008 (E) 3 Foreword This document (CEN/TS 15750:2008) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials”, the secretariat of which is held by DIN. Attention is drawn to the possibility that some of the elements of this document may be the
19、subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. 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
20、, the national standards organizations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Nether
21、lands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Licensed Copy: London South Bank University, South Bank University, 02/02/2009 05:59, Uncontrolled Copy, (c) BSI DD CEN/TS 15750:2006 CEN/TS 15750:2008 (E) 4 1 Scope This document specifi
22、es two different methods (Methods A and B) for the determination of the total nitrogen content in fertilizers. Method A specifies the titrimetric method after distillation according to ISO 5315:1984 2. Method B specifies a method by reduction of nitrate with iron and tin(II)-chloride. 2 Normative re
23、ferences 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, Fertilizers and liming materi
24、als - 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 fertilizers EN IS
25、O 385:2005, Laboratory glassware Burettes (ISO 385:2005) EN ISO 3696, Water for analytical laboratory use - Specification and test methods (ISO 3696:1987) 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 Princi
26、ple 4.1 Method A Titrimetric method after distillation according to ISO 5315:1984 Reduction of nitrate to ammonia by chromium powder in acid medium. Conversion of organic and urea nitrogen into ammonium sulfate by digestion with concentrated sulfuric acid in the presence of a catalyst. Distillation
27、of the ammonia from an alkaline solution, absorption in an excess of standard volumetric sulfuric acid solution and back-titration with standard volumetric sodium hydroxide solution in the presence of methyl red or screened methyl red as indicator. 4.2 Method B Reduction of nitrate with iron and tin
28、(II)-chloride Reduction of nitrate to ammonia by iron powder and tin chloride in acid medium. Conversion of organic and urea nitrogen into ammonium sulfate by digestion with concentrated sulfuric acid in the presence of a catalyst. Distillation of the ammonia from an alkaline solution, absorption in
29、 an excess of standard volumetric sulfuric acid solution and back-titration with standard volumetric sodium hydroxide solution in the presence of an indicator solution. Licensed Copy: London South Bank University, South Bank University, 02/02/2009 05:59, Uncontrolled Copy, (c) BSI DD CEN/TS 15750:20
30、06 CEN/TS 15750:2008 (E) 5 5 Sampling and sample preparation Sampling is not part of the methods specified in this Technical Specification. A recommended sampling method is given in EN 1482-1 1. Sample preparation shall be carried out in accordance with EN 1482-2. 6 Method A 6.1 Reagents 6.1.1 Gener
31、al Use only reagents of recognized analytical grade having, in particular, low nitrogen contents and distilled or demineralized water (grade 3 according to EN ISO 3696). 6.1.2 Chromium metal, powder, of particle size less than or equal to 250 m; 6.1.3 Aluminium oxide, fused, pumice is suitable; 6.1.
32、4 Anti-foaming agent, for example paraffin wax of melting point not lower than 100 C, or a silicone; 6.1.5 Ammonium nitrate, dried at 100 C to constant mass; 6.1.6 Digestion catalyst mixture, finely ground, comprising potassium sulfate (K2SO4): 1 000 g copper(II) sulfate pentahydrate (CuSO4.5H2O): 5
33、0 g 6.1.7 Sulfuric acid, concentrated, approximately 1,84 g/ml; 6.1.8 Hydrochloric acid, concentrated, approximately 1,18 g/ml; 6.1.9 Sodium hydroxide, approximately 400 g/l solution; 6.1.10 Sodium hydroxide, standard volumetric solution, c(NaOH)=0,10 mol/l; 6.1.11 Sulfuric acid, standard volumetric
34、 solution, c(H2SO4)=0,25 mol/l; 6.1.12 Sulfuric acid, standard volumetric solution, c(H2SO4)=0,10 mol/l; 6.1.13 Sulfuric acid, standard volumetric solution, c(H2SO4)=0,05 mol/l; 6.1.14 Indicator solution, Use either the screened methyl red solution (6.1.14.1) or the methyl red solution (6.1.14.2). L
35、icensed Copy: London South Bank University, South Bank University, 02/02/2009 05:59, Uncontrolled Copy, (c) BSI DD CEN/TS 15750:2006 CEN/TS 15750:2008 (E) 6 6.1.14.1 Screened methyl red, ethanolic indicator solution; Mix 50 ml of a 2 g/l ethanolic solution of methyl red with 50 ml of a 1 g/l ethanol
36、ic solution of methylene blue. 6.1.14.2 Methyl red, ethanolic indicator solution; Dissolve 0,1 g of methyl red in 50 ml of 95 % (volume fraction) ethanol; 6.1.15 pH indicator paper, wide range. 6.2 Apparatus 6.2.1 General Common laboratory equipment and glassware, in particular equipment according t
37、o 6.2.2 to 6.2.6. 6.2.2 Digestion apparatus, comprising an 800 ml Kjeldahl flask and a pear-shaped hollow glass stopper; 6.2.3 Distillation apparatus The components of the distillation apparatus may be connected by means of rubber bungs and tubing or by the use of spherical ground glass joints. Sphe
38、rical ground glass joints should be held spring clamps to ensure that they are leak tight. Rubber bungs and tubing shall be replaced when they begin to perish or show signs of wear. Suitable apparatus is illustrated in Figure 1. An automatic distillation apparatus may also be used, provided that the
39、 results are statistically equivalent. Licensed Copy: London South Bank University, South Bank University, 02/02/2009 05:59, Uncontrolled Copy, (c) BSI DD CEN/TS 15750:2006 CEN/TS 15750:2008 (E) 7 Dimensions in millimetres Key 1 Kjeldahl flask (6.2.2) or round-bottomed, long-necked flask of 1 000 ml
40、 capacity 2 distillation tube with a single-bulb splash head, connected to the condenser by means of a spherical joint (No 18) (the spherical joint for the connection to the condenser may be replaced by an appropriate rubber connection) 3 funnel with a polytetrafluoroethylene (PTFE) tap (6) (the tap
41、 may likewise be replaced by a rubber connection with a clip) 4 seven-bulb condenser with spherical joint (No 18) at the entrance and joined at the issue to a glass extension tube by means of a small rubber connection (when the connection to the distillation tube is effected by means of a rubber tub
42、e, the spherical joint may be replaced by a suitable rubber bung) 5 500 ml flask in which the distillate is collected 6 PTFE-tap a hole Figure 1 Typical distillation apparatus (using a round bottom flask) Licensed Copy: London South Bank University, South Bank University, 02/02/2009 05:59, Uncontrol
43、led Copy, (c) BSI DD CEN/TS 15750:2006 CEN/TS 15750:2008 (E) 8 6.2.4 Anti-bumping granules, or anti-bumping device, consisting of a 100 mm5 mm glass rod connected to a 25 mm length of polyethylene tubing; 6.2.5 Two burettes, of capacity 50 ml, according to EN ISO 385:2005, I class A; 6.2.6 Glass bea
44、ds, of diameter 2 mm to 3 mm. 6.3 Procedure 6.3.1 Test portion Weight, to the nearest 0,001 g, between 0,5 g and 2,0 g of the test sample, containing not more than 60 mg of nitrate nitrogen and 235 mg of total nitrogen. 6.3.2 Determination 6.3.2.1 Reduction NOTE 1 This step is not required if nitrat
45、e nitrogen is known to be absent. Transfer the test portion (6.3.1) to the flask (6.2.2) and add sufficient water to make up the total volume to 35 ml. Allow the flask to stand for 10 min with occasional gentle swirling to ensure dissolution of all nitrate salts. Add 1,2 g of the chromium powder (6.
46、1.2) and 7 ml of the hydrochloric acid solution (6.1.8). Allow the flask to stand for at least 5 min, but not more than 10 min, at ambient temperature. Place the flask on a heating device in a fume cupboard with the heat input regulated to pass a 7 min to7,5 min boil test and heat the flask for 4,5
47、min. Remove from the heat and allow to cool. NOTE 2 The heat input is that required to bring 250 ml of water at 25 C to a “rolling“ boil in 7 min to 7,5 min. 6.3.2.2 Hydrolysis NOTE This step can be used instead of the digestion (6.3.2.3) if it is known that the only forms of organic nitrogen presen
48、t are urea and cyanamide forms. Stand the flask in a fume cupboard and add 1,5 g of the fused aluminium oxide (6.1.3). Carefully add 25 ml of the sulfuric acid (6.1.7) to the flask. Insert the pear-shaped hollow glass stopper into the neck of the flask and place on a heating device and initially hea
49、t until gently boiling. Then adjust the heat input to pass a 7 min to 7,5 min boil test (see 6.3.2.1, NOTE 2). Continue to heat the flask and contents until dense white fumes of sulfuric acid have been involving for at least 15 min. Allow the flask to cool to room temperature and carefully add 250 ml of water. Allow the flask to cool. 6.3.2.3 Digestion NOTE This step is necessary only if organic forms of nitrogen other than urea or cyanamide forms are present (see 6.3.2.2) or in the case of fertilizers of unknown composition. Place the flask i