1、BRITISH STANDARD BS 4267-6: 1987 Ammonium nitrate Part 6: Method for determination of water content NOTEIt is recommended that this Part of BS 4267 be read in conjunction with the information in the “General introduction”, published separately as BS 4267-0. WARNING. Ammonium nitrate is a strong oxid
2、izing agent. If necessary, break the test sample up by crushing rather than grinding. UDC 661.525:546.39175:543BS4267-6:1987 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffect
3、on 30 September 1987 BSI 10-1999 The Committees responsible forthis British Standard are shown inPart 0. The following BSI references relate to the work on this standard: Committee reference CIC/21 Draft for comment 84/54870 DC ISBN 0 580 16119 6 Foreword This Part of BS 4267 has been prepared under
4、 the direction of the Chemicals Standards Committee. It supersedes clause 8 of BS 4267:1968, upon which it is based and which has been deleted by amendment. This Part of BS 4267 is related to ISO 5791 “Ammonium nitrate for industrial use Determination of water content Karl Fischer method” published
5、by the International Organization for Standardization (ISO). This standard describes a method of test only, and should not be used or quoted as a specification defining limits of purity. Reference to this Part should indicate that the method of test used is in accordance with BS4267-6:1987. A Britis
6、h Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front
7、cover, an inside front cover, pages i and ii, pages 1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publicati
8、on Amd. No. Date of issue CommentsBS4267-6:1987 BSI 10-1999 i Contents Page Foreword Inside front cover 1 Scope 1 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Procedure 1 6 Expression of results 1 7 Test report 1 Publications referred to Inside back coverii blankBS4267-6:1987 BSI 10-1999 1 1 Scope Thi
9、s Part of BS 4267 describes a method for determination of the water content of ammonium nitrate for industrial use. The method is applicable to products with a water content of not less than0.05% (m/m). NOTEThe titles of the publications referred to in this standard are listed on the inside back cov
10、er. 2 Principle Water is reacted in a test portion with a solution of iodine and sulphur dioxide in a pyridine-methanol mixture (Karl Fischer reagent), standardized previously by titration with a known mass of water. The end point of the reaction is detected by a direct electrometric method. 3 Reage
11、nts During the analysis, use only reagents of recognized analytical grade and water complying with BS3978. The reagents described in 2.3 and 2.4 of BS2511:1970 are required. 4 Apparatus The apparatus described in 3.2 of BS 2511:1970 is required. 5 Procedure 5.1 Test portion According to the expected
12、 water content weigh, to the nearest 0.01 g, a test portion requiring not more than 20 mL of the Karl Fischer reagent and, in any case, of mass not more than10g. 5.2 Standardization of the Karl Fischer reagent Standardize the Karl Fischer reagent according to the procedure described in 3.4.1 and 3.4
13、.2 of BS2511:1970. 5.3 Determination Add 50 mL of dry methanol to the reaction vessel. Pass a slow stream of dry nitrogen, sufficient to produce adequate agitation, through the reaction vessel, close the electrical circuit and titrate with the Karl Fischer reagent as before. Ignore this titration, a
14、nd immediately add the test portion (5.1), quickly replace the stopper of the reaction vessel and once dissolved, titrate with the Karl Fischer reagent. 6 Expression of results The water content, expressed as a percentage by mass of H 2 O, is given by the following expression: where 7 Test report Th
15、e test report shall include the following information: a) an identification of the sample; b) a reference to this British Standard, i.e.BS4267-6:1987; c) the results expressed in accordance with clause6; d) any unusual features noted during the determination; e) any operation not included in this Pa
16、rt of BS4267 or regarded as optional. V is the volume of the Karl Fischer reagent used in the determination (in mL); F is the water equivalent of the Karl Fischer reagent (5.2) (in mg/mL); m is the mass of the test portion (5.1) (in g). VF 100 m 1000 - VF 10m - =2 blankBS4267-6:1987 BSI 10-1999 Publ
17、ications referred to BS 2511, Methods for the determination of water (Karl Fischer method). BS 3978, Specification for water for laboratory use . BS 4267-6: 1987 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing Bri
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