1、BRITISH STANDARDBS EN 14787:2005Fertilizers and liming materials Determination of water content Guidelines and recommendationsThe European Standard EN 14787:2005 has the status of a British StandardICS 65.080g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50
2、g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 14787:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 27 June 2005 BSI 27 June 2005ISBN 0 580 46128 9National forewordThis B
3、ritish Standard is the official English language version of EN 14787:2005.The UK participation in its preparation was entrusted to Technical Committee CII/37, Fertilizers and related chemicals, which has the responsibility to:A list of organizations represented on this committee can be obtained on r
4、equest to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogueunder the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI E
5、lectronic Catalogue or of British Standards Online.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 does not of itself confer immunity from legal obligations. aid enquirers to
6、 understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comp
7、rises a front cover, an inside front cover, the EN title page, pages 2 to 10, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENN
8、EEUROPISCHE NORMEN 14787May 2005ICS 65.080English versionFertilizers and liming materials - Determination of water content -Guidelines and recommendationsEngrais et amendements minraux basiques -Dtermination de la teneur en eau - Guide etrecommandationsDngemittel und Calcium-/Magnesium-Bodenverbesse
9、rungsmittel - Bestimmung desWassergehaltes - Leitlinien und EmpfehlungenThis European Standard was approved by CEN on 21 March 2005.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 stand
10、ard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other lang
11、uage made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germ
12、any, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Ce
13、ntre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14787:2005: EEN 14787:2005 (E) 2ContentsPage Foreword3Introduction .41 Scope 52 Normative references 53 Terms and definitions .54 Methods
14、for water determination.64.1 General64.2 Gravimetric methods.64.3 Extraction methods .74.4 Overview of existing methods75 Effect of grinding on water content .96 Summary.9Bibliography 10EN 14787:2005 (E) 3Foreword This document (EN 14787:2005) has been prepared by Technical Committee CEN/TC 260 “Fer
15、tilizers 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 latest by November 2005, and conflicting national standards shall be withdrawn at the
16、 latest by November 2005. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
17、Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14787:2005 (E) 4Introduction There are, at present, four standard methods (EN 12048, EN 12049, EN 13466-1 and EN 13466-2) available for t
18、he determination of the water content in fertilizers and liming materials. Product quality characteristics of fertilizers, especially physical and bulk behaviour properties, with effects on storing and handling, are to a major extent governed by the water content of the solid fertilizer. Consequentl
19、y the water content is a very important parameter in production and product quality control. The term “moisture content“ is often used to describe the amount of water present in a fertilizer. EN 14787:2005 (E) 51 Scope This document gives guidance on the choice for the appropriate method for the det
20、ermination of the water content, considering the form under which it is present in a specific fertilizer type, and on the interpretation of the results. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the ed
21、ition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12048, Solid fertilizers and liming materials - Determination of moisture content - Gravimetric method by drying at (105 +/- 2)C (ISO 8190:1992, modified).EN 12049, Solid
22、 fertilizers and liming materials - Determination of moisture content - Gravimetric method by drying under reduced pressure (ISO 8189:1992, modified).EN 12944-2, Fertilizers and liming materials and soil improvers - Vocabulary - Part 2: Terms relating to fertilizers. EN 13466-1, Fertilizers - Determ
23、ination of water content (Karl Fischer methods) - Part 1: Methanol as extracting medium. EN 13466-2, Fertilizers - Determination of water content (Karl Fischer methods) - Part 2: 2-propanol as extracting medium. 3 Terms and definitions For the purposes of this European Standard, the following terms
24、and definitions apply. NOTE Water can be present in a number of forms (see 1). It can be present as a contaminant from the atmosphere or it may be chemically bound within the sample. 3.1essential waterwater, in stoichiometric quantities, that forms an integral part of the molecular or crystal struct
25、ure 3.2water of crystallisation essential water present in a stable solid hydrate 3.3water of constitution essential water that is released when the solid decomposes 3.4non-essential waterwater, in non-stoichiometric quantities, that is retained as a consequence of physical forces NOTE The term “fre
26、e water“ is often used to describe non-essential water and best correlates to the physical properties and bulk behaviour. EN 14787:2005 (E) 63.5adsorbed water non-essential water that is retained on the surface of solids in a humid environment NOTE The amount of water that is adsorbed depends on the
27、 fertilizer type, humidity, temperature and the specific surface area of the solid. 3.6absorbed water non-essential water that is held as a condensed phase in the capillaries of the solid NOTE The quantity contained in the solid is greatly dependent upon temperature and humidity. 3.7occluded water l
28、iquid water entrapped in microscopic pockets throughout solid crystals 4 Methods for water determination 4.1 General The extent to which essential waters are removed from the sample by drying procedures, or even chemical methods such as the Karl Fischer method, is strongly dependent upon the propert
29、ies of the water of crystallization and the crystal structure itself, although the Karl Fischer method is considered to be more effective in its determination. In any determination, some water will be completely removed, some will be partly removed and some might not be removed at all. This makes th
30、e interpretation of the results of the water determination in fertilizers even more complex as there are an enormous variety of components present in fertilizers. As is described in EN 13466-1 and EN 13466-2, the extracting medium also plays an important role in the Karl Fischer methods for determin
31、ation of water contents. 4.2 Gravimetric methods 4.2.1 General In general, drying of the sample in an oven is a quite commonly used method for the determination of the water content in a solid sample. The loss of mass, until the mass of the sample becomes constant, will then be a measure for the amo
32、unt of water. The great virtue of this kind of analysis is its simplicity, but as there are some other processes besides the evolution of water being possible during the heating, the results are not necessarily the most reliable for all kinds of products. The most probable side effects are the volat
33、ilisation of other components and decomposition of one or more constituents resulting in gaseous products. Adsorbed water is quite easily removed at temperatures above 100 C and the equilibrium is already reached after a relatively short time. Heating at 105 C, as is done in EN 12048, therefore will
34、 remove practically all the adsorbed water of the sample. There might even be, to a certain extent, a removal of some essential water. Absorbed water and occluded water are not so readily removed by drying at 105 C. In case of these forms of water it can take much more time to reach a constant mass
35、or much higher temperatures. And even then, the removal of the water often is quite incomplete. EN 14787:2005 (E) 7There are two European Standard methods available. 4.2.2 EN 12048 Solid Fertilizers and liming materials - Determination of moisture content - Gravimetric method by drying at (1052) C.
36、The principle of the method is drying a test portion at (1052) C for 5 h and determination of the resulting loss in mass. The result is expressed as mass fraction in percent. 4.2.3 EN 12049 Solid Fertilizers and liming materials - Determination of moisture content - Gravimetric method by drying unde
37、r reduced pressure. The principle of the method is drying a test portion at a pressure of (66 X 103) Pa and a temperature of 25 C for 24 h and determination of the resulting loss in mass. The result is expressed as mass fraction in percent. 4.3 Extraction methods 4.3.1 Introduction There are two Eur
38、opean Standard methods available. 4.3.2 EN 13466-1 Fertilizers - Determination of water content - Karl Fischer methods - Part 1: Methanol as extracting medium. The principle of the method is extraction of water from the fertilizer into methanol and titration of the extracted water with a Karl Fische
39、r reagent, previously standardized by titration with a known mass of water. The method is differentiated for fertilizers dispersible or soluble in methanol, and those not dispersible in methanol. The result, expressed as mass fraction in percent, includes “free water“ and extracted water of crystall
40、ization of a number of components, possibly present in fertilizers. 4.3.3 EN 13466-2 Fertilizers - Determination of water content - Karl Fischer methods - Part 2: 2-Propanol as extracting medium The principle of the method is extraction of water from the fertilizer into 2-propanol, separation of the
41、 clear solution and titration of the extracted water with a Karl Fischer reagent, previously standardized by titration with a known mass of water. The result, expressed as a mass fraction in percent, includes “free water“ and extracted water of crystallization of a limited number of components, poss
42、ibly present in fertilizers. 4.4 Overview of existing methods Table 1 gives an overview of the four existing standard methods for the determination of the water content in fertilizers and liming materials. For fertilizer types that are not listed, the applicability and precision of the methods shoul
43、d be further examined. It is vital to mention the applied method when reporting any results for water. EN 14787:2005 (E) 8Table 1 Existing standard methods Method (EN) Applicable to (for example) Not applicable to (for example) Forms of water EN 12048 - solid siliceous liming materials - solid carbo
44、nic liming materials - solid phosphatic fertilizers of type: Super phosphates natural phosphates ground phosphates partially solubilized rock phosphates - hydrated or burnt lime - ammonium compounds - magnesium sulphates MoistureaEN 12049 fertilizers and liming materials containing: calcium nitrate
45、calcium hydroxide calcium sulphate containing less than two molecules of crystal water magnesium sulphate containing one to seven molecules of crystal water salts which effloresce readily at ambient temperatures or which absorb water MoistureaEN 13466-1 all solid mineral fertilizers includes “free w
46、ater“ and extracted water of crystallization of a number of components, possibly present in fertilizers EN 13466-2 all solid mineral fertilizers includes “free water“ and extracted water of crystallization of a limited number of components, possibly present in fertilizers aFor a definition of moistu
47、re refer to EN 12944-2. The determination of the moisture content of fertilizers is specified in EN 12048 and EN 12049. EN 14787:2005 (E) 95 Effect of grinding on water content The water content of a solid is frequently altered considerably during the grinding or crushing process. An increase as wel
48、l as a decrease of the water content can be observed. A decrease of the water content for example can be found when a solid containing water of crystallization is ground. Local heating during the grinding or crushing will most probably be the reason for this phenomenon. Besides a loss of water, grin
49、ding can also cause the loss of ammonia due to this heating effect. Occluded water can also evaporate by breaking some cavities during crushing, resulting in a decrease of water content. On the other hand, grinding might also cause extra take up of water, due to an increase in surface exposed to the atmosphere and the hygroscopic properties of the product, which are of special importance in the case of fertilizers. There is a high risk of water uptake during sampling, sample preparation and storage. Any mistake in this respect might result i
