1、BS EN 15561:2009ICS 65.080NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDFertilizers Determination of totalnitrogen in calciumcyanamide containingnitratesThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 30 Ju
2、ne 2009 BSI 2009ISBN 978 0 580 62389 9Amendments/corrigenda issued since publicationDate CommentsBS EN 15561:2009National forewordThis British Standard is the UK implementation of EN 15561:2009. Itsupersedes DD CEN/TS 15561:2007 which is withdrawn.The UK participation in its preparation was entruste
3、d to TechnicalCommittee CII/37, Fertilisers 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
4、.Compliance with a British Standard cannot confer immunityfrom legal obligations.BS EN 15561:2009EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15561January 2009ICS 65.080 Supersedes CEN/TS 15561:2007 English VersionFertilizers - Determination of total nitrogen in calcium cyanamidecontaining nitr
5、atesEngrais - Dosage de lazote total dans la cyanamidecalcique nitrateDngemittel - Bestimmung von Gesamtstickstoff innitrathaltigem KalkstickstoffThis European Standard was approved by CEN on 6 December 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate th
6、e conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and 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
7、three official versions (English, French, German). A version in any other language made by translationunder the responsibility 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
8、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, Switzerland and United Kingdom.EUROPEAN COM
9、MITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2009 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15561:2009: EBS EN 15561:2009EN 15561:2
10、009 (E) 2 Contents Page Foreword 3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Principle 4 5 Reagents .4 6 Apparatus .6 7 Sampling and sample preparation 11 8 Procedure 11 9 Calculation and expression of the result . 13 10 Test report . 14 Bibliography . 15 BS EN 15561:2009EN 155
11、61:2009 (E) 3 Foreword This document (EN 15561:2009) 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
12、 by endorsement, at the latest by July 2009, and conflicting national standards shall be withdrawn at the latest by July 2009. 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 id
13、entifying any or all such patent rights. This document supersedes CEN/TS 15561:2007. 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 organization
14、s of the following countries are bound to implement this European Standard: 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,
15、Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. BS EN 15561:2009EN 15561:2009 (E) 4 1 Scope This European Standard specifies a method for the determination of total nitrogen in calcium cyanamide. The method is applicable to calcium cyanamide containing nitrates. 2 Normative re
16、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
17、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 ISO 3696:1995,
18、 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 Principle Reduction of nitrate nitrogen to ammonia with metallic iron and sta
19、nnous chloride solution. Digestion in sulfuric acid. Distillation of the ammonia from an alkaline solution, absorption 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 analy
20、tical grade and distilled or demineralized water, free from carbon dioxide and all nitrogenous compounds (grade 3 according to EN ISO 3696:1995). 5.2 Sulfuric acid, = 1,84 g/ml. 5.3 Powdered iron, reduced in hydrogen. 5.4 Potassium sulfate, p.a., finely pulverized. 5.5 Sulfuric acid (for variant a),
21、 c = 0,05 mol/l. BS EN 15561:2009EN 15561:2009 (E) 5 5.6 Sodium or potassium hydroxide standard solution (for variant a), carbonate free, c = 0,1 mol/l. 5.7 Sulfuric acid (for variant b, see NOTE in 8.2), c = 0,1 mol/l. 5.8 Sodium or potassium hydroxide standard solution (for variant b, see NOTE in
22、8.2), carbonate free, c = 0,2 mol/l. 5.9 Sulfuric acid (for variant c, see NOTE in 8.2), c = 0,25 mol/l. 5.10 Sodium or potassium hydroxide standard solution (for variant c, see NOTE in 8.2), carbonate free, c = 0,5 mol/l. 5.11 Indicator solutions 5.11.1 Mixed indicator Solution A: Dissolve 1 g of m
23、ethyl 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 violet in acid solution, grey in neutral solution and gr
24、een 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 (4 to 5 drops) instead of that specified in 5.11.1.
25、 5.12 Stannous chloride solution Dissolve 120 g of SnCl22H2O in 400 ml of concentrated hydrochloric acid (20= 1,18 g/ml) and make up to 1 l with water. The solution shall be completely clear and prepared immediately before use. It is essential to check the reducing power of the stannous chloride: di
26、ssolve 0,5 g of SnCl22H2O in 2 ml of concentrated hydrochloric acid (20= 1,18 g/ml) and make up to 50 ml with water. Then add 5 g of Rochelle salt (potassium sodium tartrate), then a sufficient quantity of sodium bicarbonate for the solution to be alkaline to litmus paper. Titrate with an iodine sol
27、ution (I2) of c = 0,05 mol/l in the presence of a starch solution as an indicator. 1 ml of iodine solution (I2) of c = 0,05 mol/l corresponds to 0,011 28 g of SnCl22H2O. At least 80 % of the total tin present in the solution thus prepared shall be in bivalent form. For the titration at least 35 ml o
28、f the c = 0,1 mol/l iodine solution (I2) should be used. 5.13 Sodium hydroxide solution, containing about 30 % NaOH ( = 1,33 g/ml), ammonia free. 5.14 Standard nitrate-ammoniacal solution Weigh 2,5 g of potassium nitrate and 10,16 g of ammonium sulfate and place them in a 250 ml graduated flask. Dis
29、solve in water and make up to 250 ml. 1 ml of this solution contains 0,01 g of nitrogen. BS EN 15561:2009EN 15561:2009 (E) 6 5.15 Anti-bump granules of pumice stone, washed in hydrochloric acid and calcined. 6 Apparatus 6.1 Distillation apparatus Consisting of a round-bottomed flask of suitable capa
30、city 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
31、used also, provided that the results are statistically equivalent. BS EN 15561:2009EN 15561:2009 (E) 7 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
32、spherical 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 spheric
33、al 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 tube, the spherical joint may be replaced by a suitable rubber bung) 5 500 ml flask in which the di
34、stillate is collected 6 PTFE-tap a hole Figure 1 Distillation apparatus 1 BS EN 15561:2009EN 15561:2009 (E) 8 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
35、 (No 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 t
36、ube by 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 15561:2009EN 15561:2009 (E) 9 Dimensions in millimetres Key 1 round-bottomed, long-necked flask of 750 ml or 1 000 ml capacity with,
37、 a bell 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 cond
38、enser 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 15561:2009EN 15561:2009 (E) 10 Dimensions in millimetres Key 1 round-bottomed, long-necked flask of 1 000 ml capacity
39、with 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 b
40、e replaced 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 j
41、oint 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 15561:2009EN 15561:2009 (E) 11 6.2 Kjeldahl flask, long necked and of suitable capacity. 6.3 Pipettes, of capacity 50 ml, 100 ml and 200 ml. 6.4 Grad
42、uated flask, of capacity 250 ml. 7 Sampling and sample preparation Sampling is not part of the method specified in this Technical Specification. A recommended sampling method is given in EN 1482-1. Sample preparation shall be carried out in accordance with EN 1482-2. 8 Procedure 8.1 Preparation of t
43、he solution Weigh, to the nearest 0,001 g, 1 g of the sample and place it in the Kjeldahl flask. Add 0,5 g of powdered iron (5.3) and 50 ml of the stannous chloride solution (5.12), stir and leave standing for 0,5 h. During the time it is left standing, stir again after 10 min and 20 min. Then add 1
44、0 g of potassium sulfate (5.4) and 30 ml of sulfuric acid (5.2). Bring to the boil and maintain boiling for 1 h after the appearance of white fumes. Leave to cool and dilute with 100 ml to 150 ml of water. Transfer the suspension quantitatively into a 250 ml graduated flask, cool and make up the vol
45、ume with water, stir and filter through a dry filter into a dry container. Instead of then siphoning off the suspension in order to apply the variant a, b or c, the ammoniacal nitrogen in this solution may also be distilled directly, after adding sufficient sodium hydroxide to ensure a large surplus
46、 (5.13). 8.2 Analysis of the solution According to the variant chosen, place in the receiving flask a measured quantity of standard sulfuric acid as indicated in Table 1, Table 2 or Table 3. Add the appropriate quantity of the chosen indicator solution (5.11.1 or 5.11.2) and, if necessary, water in
47、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. With a pipette, transfer, according to the variant chosen, 50 ml, 100 ml or 200 ml of the solution obtained as described in 8.1, and distil the ammonia as described
48、below, adding sufficient NaOH solution (5.13) to ensure a considerable excess. 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 cont
49、ents of the distillation flask 10 ml of concentrated sodium hydroxide solution (5.13). 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 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 extension is above the surface
