SIST-TS CEN/TS 15561:2008

SLOVENSKI STANDARD
SIST-TS CEN/TS 15561:2008
01-marec-2008
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Fertilizers - Determination of total nitrogen in calcium cyanamide containing nitrates
Düngemittel - Bestimmung von Gesamtstickstoff in nitrathaltigem Kalkstickstoff
Engrais - Détermination de l'azote total dans la cyanamide calcique nitratée
Ta slovenski standard je istoveten z: CEN/TS 15561:2007
ICS:
65.080
SIST-TS CEN/TS 15561:2008 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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TECHNICAL SPECIFICATION
CEN/TS 15561
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
April 2007
ICS 65.080

English Version
Fertilizers - Determination of total nitrogen in calcium cyanamide
containing nitrates
Engrais - Détermination de l'azote total dans la cyanamide Düngemittel - Bestimmung von Gesamtstickstoff in
calcique nitratée nitrathaltigem Kalkstickstoff
This Technical Specification (CEN/TS) was approved by CEN on 1 January 2007 for provisional application.
The period of validity of 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 way 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 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, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 15561:2007: E
worldwide for CEN national Members.

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CEN/TS 15561:2007 (E)
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 .14
10 Test report .14
Bibliography .15

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CEN/TS 15561:2007 (E)
Foreword
This document (CEN/TS 15561:2007) has been prepared by Technical Committee CEN/TC 260 “Fertilizers
and liming materials”, the secretariat of which is held by DIN.
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
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, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and United Kingdom.
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CEN/TS 15561:2007 (E)
1 Scope
This Technical Specification specifies a method for the determination of total nitrogen in calcium cyanamide.
The method is applicable to calcium cyanamide containing nitrates.
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, 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 fertilizers
EN ISO 3696:1995, 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 tin(II)chloride. 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 analytical 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
ρ = 1,84 g/ml
5.3 Powdered iron
reduced in hydrogen
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CEN/TS 15561:2007 (E)
5.4 Potassium sulfate
p.a., finely pulverized
5.5 Sulfuric acid (for variant a)
c = 0,05 mol/l
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 2)
c = 0,1 mol/l
5.8 Sodium or potassium hydroxide standard solution (for variant b, see NOTE 2)
carbonate free, c = 0,2 mol/l
5.9 Sulfuric acid (for variant c, see NOTE 2)
c = 0,25 mol/l
5.10 Sodium or potassium hydroxide standard solution (for variant c, see NOTE 2)
carbonate free, c = 0,5 mol/l
5.11 Indicator solutions
5.11.1 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 violet 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 (4 to 5 drops) instead of that specified in 5.11.1.
5.12 Tin(II)chloride solution
Dissolve 120 g of SnCl 2H O in 400 ml of concentrated hydrochloric acid (ρ = 1,18g/ml) and make up to 1 l
2 2
with water. The solution shall be completely clear and prepared immediately before use.
NOTE It is essential to check the reducing power of the tin(II)chloride, using the following procedure. 0,5 g of
SnCl 2H O are dissolved in 2 ml of concentrated hydrochloric acid (ρ = 1,18g/ml) and made up to 50 ml with water. Then
2 2
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CEN/TS 15561:2007 (E)
5 g of Rochelle salt (potassium sodium tartrate) are added and a sufficient quantity of sodium bicarbonate for the solution
to show an alkaline reaction to a litmus paper test.
It is titrated with an iodine solution of c = 0,1 mol/l in the presence of a starch solution as an indicator.
1 ml of iodine solution c = 0,1 mol/l corresponds to 0,011 28 g of SnCl22H2O.
At least 80 % of the total tin present in the solution thus prepared needs to be in a bivalent form. For the titration at least
35 ml of the c = 0,1 mol/l iodine solution should be used.
5.13 Sodium hydroxide solution
containing about 30 % NaOH (ρ = 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. Dissolve in water and make up to 250 ml. 1 ml of this solution contains 0,01 g of nitrogen.
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 capacity 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 also, provided that the results are statistically equivalent.
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CEN/TS 15561:2007 (E)
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
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 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 tube, the spherical join
...