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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 661.525:546.39175:543 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:28:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4267-9:1987 This British Standard, having been prepared under the direction
3、 of the Chemicals Standards Committee, was published under the authority of the Board of BSI and comes into effect on 30 September 1987 BSI 10-1999 The Committees responsible for this British Standard are shown in Part 0. The following BSI references relate to the work on this standard: Committee re
4、ference CIC/21 Draft (ref. 86/53126) announced in BSI News, September 1986 ISBN 0 580 16122 6 Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:28:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4267-9:1987 BSI 10-1999i Conte
5、nts Page Forewordii 1Scope1 2Principle1 3Reagents1 4Apparatus1 5Procedure1 6Expression of results2 7Test report2 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:28:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4267-9:1987 ii BSI 10-1999 Foreword
6、 This Part of 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 BS 4267 is related to ISO 3329 “Ammonium nitrate for industrial use D
7、etermination of 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 Part should ind
8、icate that the method of test used is in accordance with BS 4267-9:1987. 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 i
9、mmunity from legal 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
10、 the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:28:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4267-9:1987 BSI 10-19991 1 Scope This Part of BS 4267 describes a method for determination of sulphate content of ammonium nitrate for industr
11、ial use. The method is applicable to products with a sulphate content of between 10 mg/kg and 200 mg/kg. NOTEThe titles of the 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
12、residue is dissolved in hot water, the solution filtered and the sulphate precipitated by the addition of barium chloride solution. 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 analys
13、is, use only reagents of recognized analytical grade and water complying with BS 3978. 3.2 Sodium carbonate, free from sulphate (see 5.3). 3.3 Hydrochloric acid solution, c(HCl) = 2 mol/L approximately. 3.4 Sulphuric acid solution, c(“H2 SO4) = 0.002 mol/L. 3.5 Sulphate seeding reagent, freshly prep
14、ared. Dissolve 2.0 g of barium chloride dihydrate, BaCl2. 2H2 O, in 75 mL of water, add 20 mL of 95 % (V/V) ethanol and 5 mL of the sulphuric acid solution (3.4). 4 Apparatus 4.1 Six matched Nessler cylinders, complying with BS 612. 4.2 Burette, class A, 25 mL, graduated in 0.05 mL, complying with B
15、S 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, capable of being maintained at 600 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
16、 range of standard solutions at the same time as the determination. Using one Nessler cylinder (4.1) for each standard solution, 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 to 20 mL with water, add 1 mL of the sulphate seeding reagent (
17、3.5), mix well and stand for 5 min. These standard solutions contain 196 4g to 980 4g sulphate, as H2SO4, i.e. approximately 200 4g to 1 000 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 aci
18、d 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 the 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 sol
19、ution. 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 sodium 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
20、 white fumes have ceased to be evolved. Heat the dish at 600 10 C in the furnace (4.5) for 15 min. Allow to cool. WARNING. If the 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 f
21、ilter into the volumetric flask (4.3). Wash the filter paper with several portions of water and dilute to the mark. 5.4.2 Turbidity 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 th
22、e sulphate content is expected to be between 40 mg/kg and 200 mg/kg transfer 5.0 mL of the test solution (5.4.1) to one of the Nessler 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
23、 the standard solutions (5.2) and note the sulphate content (in 4g) of the sulphate standard which it most nearly matches. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:28:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4267-9:1987 2 BSI 10-1999 6 Expression of results The sulphate cont
24、ent, expressed as sulphuric acid (H2SO4), 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 Standard method, i.e. BS 4267-9:1987; c) the results expressed in
25、accordance with clause 6; d) any unusual features noted during the determination; e) any operation not included in this Part of BS 4267 or regarded as optional. Mis the mass of H2SO4(in 4g), in the sulphate standard, the turbidity of which most nearly matches that produced from the test solution (5.
26、4.2); Vis the volume of the test solution (5.4.1) taken (in mL). M V - - Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:28:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4267-9:1987 BSI 10-1999 Publications referred to BS 612, Specification for Nessler cylinders. BS 846, Specification f
27、or burettes. BS 1792, Specification for one-mark volumetric flasks. BS 3978, Specification for water for laboratory use. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 08:28:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 4267-9: 1987 BSI 389 Chiswick High Road London W4 4AL BSI British Sta
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