1、BRITISH STANDARD BS4258-3: 1989 Methods of test for Phosphoric acid (orthophosphoric acid) for industrial use Part 3: Determination of sulphate contentBS4258-3:1989 This British Standard, having been prepared under the directionof the Chemicals Standards Policy Committee, waspublished under the auth
2、orityof the Board of BSI andcomes into effect on 29September1989 BSI 10-1999 First published September 1975 First revision September 1989 The following BSI references relate to the work on this standard: Committee reference CIC/25 Draft for comment87/53564 DC ISBN0 580 17054 3 Committees responsible
3、 for this British Standard The preparation of this British Standard was entrusted by the Chemicals Standards Policy Committee (CIC/-) to Technical Committee CIC/37, upon which the following bodies were represented: Association of Public Analysts British Coal Corporation Chemical Industries Associati
4、on Department of Trade and Industry (Laboratory of the Government Chemist) Fertiliser Manufacturers Association Ltd. Institute of Trading Standards Administration Ministry of Agriculture, Fisheries and Food Ministry of Defence Amendments issued since publication Amd. No. Date of issue CommentsBS4258
5、-3:1989 BSI 10-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Procedure 1 6 Calculation and expression of results 1 7 Test report 1 Publications referred to Inside back coverBS4258-3:1989 ii BSI 10-1999 Foreword This Pa
6、rt of BS4258 has been prepared under the direction of the Chemicals Standards Policy Committee to provide methods for the analysis of phosphoric acid (orthophosphoric acid) for industrial use. This Part supersedes BS4258-3:1975, which is withdrawn, and from which it differs by making substantial ref
7、erence toBS6337-1, possession of which is essential. This Part includes a procedure for the preparation of a test portion suitable for subsequent treatment and determination of sulphate content in accordance with the general method which reflects current practice in technique and presentation. This
8、Part is closely related toISO2997, from which it differs in the same way as fromBS4258-3:1975. 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
9、not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 and2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This
10、will be indicated in the amendment table on the inside front cover.BS4258-3:1989 BSI 10-1999 1 1 Scope This Part of BS4258 describes a method for determination of the sulphate content of phosphoric acid (orthophosphoric acid) for industrial use. The method is applicable to products having sulphate c
11、ontents of between1mg/kg and4000mg/kg. NOTEThe titles of the publications referred to in this standard are listed on inside back cover. 2 Principle The principle is described inclause3 of BS6337-1:1983. 3 Reagents The reagents described inclause4 of BS6337-1:1983 and water complying with grade3ofBS3
12、978 are required. 4 Apparatus The apparatus described inclause5 of BS6337-1:1983 is required. 5 Procedure 5.1 Test portion Weigh, to the nearest0.001g, a test portion of between0.2g and5.0g, depending on the expected sulphate content, such that it contains between4.54g and4504g of sulphate, expresse
13、d asSO 4 , and not more than2mL of water. NOTEIt is recommended that reference be made to the information on sampling given inBS4258-12. 5.2 Determination Determine the sulphate content of the test portion by following the procedure described inclause6 ofBS6337-1:1983, using the whole of the test po
14、rtion. 6 Calculation and expression of results The sulphate content, expressed as milligrams of sulphate (SO 4 ) per kilogram, is given by the following expression: where 7 Test report The test report shall include the following information: a) a complete identification of the sample; b) a reference
15、 to this British Standard, i.e.BS4258-3:1989; c) the results expressed in accordance with clause6; d) details of any unusual features noted during the determination; e) any operation not included in this British Standard or regarded as optional. V 1 is the volume of the reagent used to titrate the h
16、ydrogen sulphide released during the determination (see5.2) (in mL); V 0 is the volume of the reagent used to titrate the hydrogen sulphide released during the blank test (see6.4 ofBS6337-1:1983) (inmL); c is the concentration of titrant(4.7 or4.8 ofBS6337-1:1983) (in mol/L); 0.096 is the mass of su
17、lphate, asSO 4 , corresponding to1.000mL of titrant, c=1.000 mol/L; m is the mass of the test portion(5.1) (in g). V 1 V 0 ()c 0.096 10 6 m -2 blankBS4258-3:1989 BSI 10-1999 Publications referred to BS 3978, Specification for water for laboratory use. BS 4258, Methods of test for phosphoric acid (or
18、thophosphoric acid) for industrial use. BS 4258-12, Guide to sampling techniques. BS 6337, General methods of chemical analysis. BS 6337-1, Method for determination of traces of sulphur compounds by reduction and titrimetry. ISO 2997, Phosphoric acid for industrial use Determination of sulphate cont
19、ent Method by reduction and titrimetry 1) . 1) Referred to in the foreword only.BS4258-3: 1989 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 a
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