1、BRITISH STANDARD BS 4267-9: 1987 Ammonium nitrate Part 9: Method for determination of sulphate 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 o
2、xidizing agent. If necessary, break the test sample up by crushing rather than grinding. UDC 661.525:546.39175:543BS4267-9:1987 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffe
3、ct on 30 September 1987 BSI 10-1999 The Committees responsible for this British Standard are shown inPart 0. The following BSI references relate to the work on this standard: Committee reference CIC/21 Draft (ref. 86/53126) announced inBSI News, September 1986 ISBN 0 580 16122 6 Amendments issued si
4、nce publication Amd. No. Date of issue CommentsBS4267-9:1987 BSI 10-1999 i Contents Page Foreword ii 1 Scope 1 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Procedure 1 6 Expression of results 2 7 Test report 2 Publications referred to Inside back coverBS4267-9:1987 ii BSI 10-1999 Foreword This Part of
5、 BS 4267 has been prepared under the direction of the Chemicals Standards Committee. It supersedes clause 12 of BS 4267:1968, to which it is technically equivalent and which has been deleted by amendment. This Part of BS4267 is related to ISO3329 “Ammonium nitrate for industrial use Determination of
6、 sulphur compounds Method by reduction and titrimetry” published 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 Partshould indicate that the m
7、ethod of test used is in accordance with BS4267-9:1987. A British 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 lega
8、l obligations. Summary of pages This document comprises a front 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 ta
9、ble on the inside front cover.BS4267-9:1987 BSI 10-1999 1 1 Scope This Part of BS 4267 describes a method for determination of sulphate content of ammonium nitrate for industrial use. The method is applicable to products with a sulphate content of between10mg/kg and 200 mg/kg. NOTEThe titles of the
10、publications referred to in this standard are listed on the inside back cover. 2 Principle A test portion is volatilized after the addition of sodium carbonate. The soluble residue is dissolved in hot water, the solution filtered and the sulphate precipitated by the addition of barium chloride solut
11、ion. The sulphate content is determined by a visual turbidimetric method, using standard solutions of sulphuric acid for reference. 3 Reagents 3.1 General. During the analysis, use only reagents of recognized analytical grade and water complying with BS3978. 3.2 Sodium carbonate, free from sulphate
12、(see 5.3). 3.3 Hydrochloric acid solution, c(HCl) = 2 mol/L approximately. 3.4 Sulphuric acid solution, c(“H 2SO 4 ) = 0.002 mol/L. 3.5 Sulphate seeding reagent, freshly prepared. Dissolve 2.0 g of barium chloride dihydrate, BaCl 2 . 2H 2O, in 75 mL of water, add 20 mL of95%(V/V) ethanol and 5 mL of
13、 the sulphuric acid solution (3.4). 4 Apparatus 4.1 Six matched Nessler cylinders, complying with BS612. 4.2 Burette, class A, 25 mL, graduated in 0.05 mL, complying with BS 846. 4.3 One-mark volumetric flask, 50 mL, complying with BS 1792. 4.4 Porcelain dish, about 100 mm in diameter. 4.5 Furnace,
14、capable of being maintained at600 10 C. 5 Procedure 5.1 Test portion Weigh, to the nearest 0.1 g, approximately 50 g of the test sample. 5.2 Standard solutions Prepare the range of standard solutions at the same time as the determination. Using one Nessler cylinder (4.1) for each standard solution,
15、add successively 2.0, 4.0, 6.0, 8.0 and 10.0 mL of the sulphuric acid solution (3.4). Make up each cylinder to20 mL with water, add 1 mL of the sulphate seeding reagent (3.5), mix well and stand for 5 min. These standard solutions contain 196 4g to 980 4g sulphate, as H 2 SO 4 , i.e. approximately 2
16、00 4g to1000 4g. 5.3 Blank test Weigh 0.02 g of the sodium carbonate (3.2) and dissolve it in 20 mL of water in a Nessler cylinder(4.1). Add 0.4 mL of the hydrochloric acid solution (3.3) and mix. Add 1 mL of the sulphate seeding reagent (3.5) and stand for 5 min. If turbidity is observed discard th
17、e sodium carbonate. Repeat this procedure with sodium carbonate from different samples, until no turbidity is observed. 5.4 Determination 5.4.1 Preparation of the test solution. Transfer the test portion (5.1) into the porcelain dish (4.4) and dissolve in about 40 mL of water. Add 0.05 g of the sodi
18、um carbonate (3.2) and place the dish on a sand bath at a temperature of approximately 120 C in a fume cupboard. When the water has evaporated, heat over a low flame until white fumes have ceased to be evolved. Heat the dish at600 10 C in the furnace (4.5) for 15 min. Allow to cool. WARNING. If the
19、ammonium nitrate is heated too rapidly, a violent decomposition may result. Dissolve the residue in 10 mL of water, add 1 mL of the hydrochloric acid solution (3.3) and filter into the volumetric flask (4.3). Wash the filter paper with several portions of water and dilute to the mark. 5.4.2 Turbidit
20、y test. If the sulphate content is expected to be between 10 mg/kg and 50 mg/kg transfer 20.0 mL of the test solution (5.4.1) to one of the Nessler cylinders (4.1). If the sulphate content is expected to be between40mg/kg and 200 mg/kg transfer 5.0 mL of the test solution (5.4.1) to one of the Nessl
21、er cylinders (4.1) and add 15.0 mL of water. Add 1 mL of the sulphate seeding reagent, mix well and stand for 5 min. Compare the turbidity produced with that of each of the standard solutions (5.2) and note the sulphate content (in 4g) of the sulphate standard which it most nearly matches.BS4267-9:1
22、987 2 BSI 10-1999 6 Expression of results The sulphate content, expressed as sulphuric acid (H 2 SO 4 ), in mg/kg, is given by the following expression: where 7 Test report The test report shall include the following information: a) an identification of the sample; b) a reference to this British Sta
23、ndard method, i.e. BS 4267-9:1987; c) the results expressed in accordance with clause6; d) any unusual features noted during the determination; e) any operation not included in this Part of BS4267 or regarded as optional. M is the mass of H 2 SO 4 (in 4g), in the sulphate standard, the turbidity of
24、which most nearly matches that produced from the test solution (5.4.2); V is the volume of the test solution (5.4.1) taken (in mL). M V -BS4267-9:1987 BSI 10-1999 Publications referred to BS 612, Specification for Nessler cylinders. BS 846, Specification for burettes. BS 1792, Specification for one-
25、mark volumetric flasks. BS 3978, Specification for water for laboratory use. BS 4267-9: 1987 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at
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