BS EN 15562-2009 Fertilizers - Determination of cyanamide nitrogen《肥料 氰胺氮的测定》.pdf

1、BS EN 15562:2009ICS 65.080NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDFertilizers Determination ofcyanamide nitrogenThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 30 June 2009 BSI 2009ISBN 978 0 580 6239

2、0 5Amendments/corrigenda issued since publicationDate CommentsBS EN 15562:2009National forewordThis British Standard is the UK implementation of EN 15562:2009. Itsupersedes DD CEN/TS 15562:2007 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CII/37, Fer

3、tilisers and related chemicals.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard

4、 cannot confer immunityfrom legal obligations.BS EN 15562:2009EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15562January 2009ICS 65.080 Supersedes CEN/TS 15562:2007 English VersionFertilizers - Determination of cyanamide nitrogenEngrais - Dtermination de lazote cyanamid Dngemittel - Bestimmung v

5、on CyanamidstickstoffThis European Standard was approved by CEN on 6 December 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and

6、bibliographical references concerning such nationalstandards 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 translationunder the responsibilit

7、y of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Irel

8、and, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36

9、B-1050 Brussels 2009 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15562:2009: EBS EN 15562:2009EN 15562:2009 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Principle 4 5 Reagents .4

10、6 Apparatus .5 7 Sampling and sample preparation 10 8 Procedure 10 9 Calculation and expression of the result . 12 10 Test report . 12 Bibliography . 13 BS EN 15562:2009EN 15562:2009 (E) 3 Foreword This document (EN 15562:2009) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and lim

11、ing 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 July 2009, and conflicting national standards shall be withdrawn at the latest by July 2009

12、. 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 CEN/TS 15562:2007. This document has been prepared under a

13、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 countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republi

14、c, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 15562:2009EN 15562:2009 (E) 4 1 Scope This Europ

15、ean Standard specifies a method for the determination of cyanamide nitrogen in fertilizers. The method is applicable to calcium cyanamide and calcium cyanamide/nitrate mixtures. 2 Normative references The following referenced documents are indispensable for the application of this document. For date

16、d 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 materials Sampling and sample preparation Part 2: Sample preparation EN 12944-1:1999, Fertilizers and liming mater

17、ials 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 ISO 3696:1995, Water for analytical laboratory use Specification and test methods (ISO 3696:1987) 3 Terms and definitions

18、For the purposes of this document, the terms and definitions given in EN 12944-1:1999 and EN 12944-2:1999 apply. 4 Principle Precipitation of cyanamide nitrogen as a silver complex. Digestion in sulfuric acid with the aid of a catalyst. Distillation of the ammonia from an alkaline solution, absorpti

19、on in an excess of standard sulfuric acid solution and back-titration with standard sodium or potassium hydroxide solution. 5 Reagents 5.1 General Use only reagents of recognized analytical grade and distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds (grade 3 ac

20、cording to EN ISO 3696:1995). 5.2 Glacial acetic acid 5.3 Ammonia solution, containing 10 % of ammonia gas by mass (20= 0,96 g/ml). 5.4 Ammoniacal silver solution, according to Tollens. Mix 500 ml of 10 % silver nitrate (AgNO3) solution in water with 500 ml of 10 % ammonia solution (5.3). Do not exp

21、ose unnecessarily to light, heat or air. The solution normally keeps for years. As long as the solution remains clear, the reagent is of good quality. BS EN 15562:2009EN 15562:2009 (E) 5 5.5 Concentrated sulfuric acid, 20= 1,84 g/ml. 5.6 Potassium sulfate, p.a. 5.7 Catalyst Use 0,3 g to 0,4 g of cop

22、per(II) oxide or 0,95 g to 1,25 g of copper(II) sulfate pentahydrate for each determination. 5.8 Sodium hydroxide solution, approximately 30 % NaOH (20= 1,33 g/ml), ammonia free. 5.9 Sulfuric acid, c = 0,05 mol/l. 5.10 Sodium or potassium hydroxide solution, c = 0,1 mol/l. 5.11 Indicator solutions 5

23、.11.1 Mixed indicator Solution A: Dissolve 1 g of methyl red in 37 ml of sodium hydroxide solution c = 0,1 mol/l and make up to 1 l with water. Solution B: Dissolve 1 g of methylene blue in water and make up to 1 l. Mix one volume of solution A with two volumes of solution B. This indicator is viole

24、t in acid solution, grey in neutral solution and green in alkaline solution. Use 0,5 ml (10 drops) of this indicator solution. 5.11.2 Methyl red indicator solution Dissolve 0,1 g of methyl red in 50 ml of 95 % ethanol. Make up to 100 ml with water and filter if necessary. This indicator may be used

25、(4 to 5 drops) instead of that specified in 5.11.1. 5.12 Anti-bump granules (i.e. pumice stone, glass pearls), washed in hydrochloric acid and calcined. 5.13 Potassium thiocyanate, for the control test. 6 Apparatus 6.1 Distillation apparatus Consisting of a round-bottomed flask of suitable capacity

26、connected to a condenser by means of a splash head. The equipment is made of borosilicate glass. NOTE The different types of equipment recommended for this determination are reproduced, showing all the features of construction, in Figures 1, 2, 3, and 4. Automatic distillation apparatus may be used

27、also, provided that the results are statistically equivalent. BS EN 15562:2009EN 15562:2009 (E) 6 Dimensions in millimetres Key 1 round-bottomed, long-necked flask of 1 000 ml capacity 2 distillation tube with a splash head, connected to the condenser by means of a spherical joint (No 18) (the spher

28、ical joint for the connection to the condenser may be replaced by an appropriate rubber connection) 3 funnel with a polytetrafluoroethylene (PTFE) tap (6) for the addition of sodium hydroxide (the tap may likewise be replaced by a rubber connection with a clip) 4 six-bulb condenser with spherical jo

29、int (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 tube, the spherical joint may be replaced by a suitable rubber bung) 5 500 ml flask in which the distill

30、ate is collected 6 PTFE-tap a hole Figure 1 Distillation apparatus 1 BS EN 15562:2009EN 15562:2009 (E) 7 Dimensions in millimetres Key 1 round-bottomed, short-necked flask of 1 000 ml capacity with a spherical joint (No 35) 2 distillation tube with a splash head, equipped with a spherical joint (No

31、35) at the entrance and a spherical joint (No 18) at the issue, connected at the side to a funnel with a polytetrafluoroethylene (PTFE) tap (5) for the addition of sodium hydroxide 3 six-bulb condenser with a spherical joint (No 18) at the entrance and joined at the issue to a glass extension tube b

32、y means of a small rubber connection 4 500 ml flask in which the distillate is collected 5 PTFE-tap a enlarged description Figure 2 Distillation apparatus 2 BS EN 15562:2009EN 15562:2009 (E) 8 Dimensions in millimetres Key 1 round-bottomed, long-necked flask of 750 ml or 1 000 ml capacity with, a be

33、ll mouth 2 distillation tube with a splash head and a spherical joint (No 18) at the issue 3 elbow tube with a spherical joint (No 18) at the entrance, and a drip cone (the connection to the distillation tube may be effected by means of a rubber tube instead of a spherical joint) 4 six-bulb condense

34、r joined at the issue to a glass extension tube by means of a small rubber connection 5 500 ml flask in which the distillate is collected Figure 3 Distillation apparatus 3 BS EN 15562:2009EN 15562:2009 (E) 9 Dimensions in millimetres Key 1 round-bottomed, long-necked flask of 1 000 ml capacity with

35、a bell mouth 2 distillation tube with a splash head and a spherical joint (No 18), at the issue, connected at the side to a funnel with a polytetrafluoroethylene (PTFE) tap (5) for the addition of sodium hydroxide (a suitable rubber bung may be used instead of the spherical joint; the tap may be rep

36、laced by a rubber connection with an appropriate clip) 3 six-bulb condenser with a spherical joint (No 18) at the entrance, joined at the issue, by a rubber connection, to a glass extension tube (when the connection to the distillation tube is effected by means of a rubber tube, the spherical joint

37、may be replaced by a suitable rubber bung) 4 500 ml flask for the collection of the distillate 5 PTFE-tap Figure 4 Distillation apparatus 4 BS EN 15562:2009EN 15562:2009 (E) 10 6.2 Graduated flask, capacity 500 ml. 6.3 Long-necked Kjeldahl flask, of suitable capacity (300 ml to 500 ml). 6.4 Pipette,

38、 capacity 50 ml. 6.5 Rotary shaker, 35 to 40 turns per minute. 7 Sampling and sample preparation Sampling is not part of the method specified in this European Standard. A recommended sampling method is given in EN 1482-1. Sample preparation shall be carried out in accordance with EN 1482-2. 8 Proced

39、ure SAFETY PRECAUTIONS When using any ammoniacal silver solution safety goggles shall be worn. As soon as a thin membrane forms on the surface of the liquid, an explosion can be produced by agitation and the greatest caution is essential. 8.1 Preparation of the solution for analysis Weigh, to the ne

40、arest 0,001 g, about 2,5 g of the prepared sample and place it in a small glass mortar. Grind the sample three times with water, pouring off the water after each grinding into a 500 ml graduated flask (6.2). Transfer quantitatively the sample into the 500 ml graduated flask, washing the mortar, pest

41、le and funnel with water. Make up with water to approximately 400 ml. Add 15 ml of acetic acid (5.2). Shake on the rotary shaker (6.5) for 2 h. Make up to 500 ml with water, mix and filter. The analysis shall be carried out as quickly as possible. 8.2 Analysis of the solution Transfer 50 ml of the f

42、iltrate into a 250 ml beaker. Add ammonia solution (5.3) until slightly alkaline and add 30 ml of warm ammoniacal silver nitrate (5.4) in order to precipitate the yellow silver complex of the cyanamide. Leave overnight, filter and wash the precipitate with cold water until it is completely free of a

43、mmonia. Place the filter and the precipitate, still moist, in a Kjeldahl flask, add 10 g to 15 g of potassium sulfate (5.6), the catalyst (5.7), in the prescribed proportion, then 50 ml of water and 25 ml of concentrated sulfuric acid (5.5). Warm the flask slowly, while shaking it gently until the c

44、ontents come to the boil. Increase the heat, boil until the contents of the flask become colourless or pale green. Continue boiling for 1 h, then leave to cool. Place in the receiving flask 50 ml of standard sulfuric acid. Add the appropriate quantity of the chosen indicator solution (5.11.1 or 5.11

45、.2) and, if necessary, water in order to obtain a volume of at least 50 ml. The end of the extension tube of the condenser shall be below the surface of the solution. BS EN 15562:2009EN 15562:2009 (E) 11 Transfer by precision pipette, according to the details given in Table 1, an aliquot portionof t

46、he clear solution, into the distillation flask of the apparatus. Add water in order to obtain a total volume of about 350 ml and several grains of pumice in order to control the boiling. Assemble the distillation apparatus and, taking care to avoid any loss of ammonia, add to the contents of the dis

47、tillation flask 10 ml of concentrated sodium hydroxide solution (5.8) (add sufficient NaOH solution (5.8) to ensure the presence of a considerable excess). Gradually warm the flask, to avoid boiling vigorously. When boiling commences, distil at the rate of about 100 ml in 10 min to 15 min; the total

48、 volume of distillate should be about 250 ml. The condenser shall be regulated so that a continuous flow of condensate is ensured. The distillation should be completed in 30 min to 40 min. When no more ammonia is likely to be evolved, lower the receiving flask so that the tip of the condenser extens

49、ion is above the surface of the liquid. Test the subsequent distillate by means of an appropriate reagent to ensure that all the ammonia is completely distilled. Wash the condenser extension with a little water and titrate the surplus acid with the standard solution of sodium or potassium hydroxide (see NOTE). NOTE Standard solutions of different strengths may be used for the back-titration provided that the volumes used for the titration do not, as far as possible, exceed 45 ml. Table 1 Weighing, dilution and calculation Declaration wN% Amount t