1、BRITISH STANDARD BS4258-5: 1989 Methods of test for Phosphoric acid (orthophosphoric acid) for industrial use Part 5: Determination of silica contentBS4258-5:1989 This British Standard, having been prepared under the directionof the Chemicals Standards Policy Committee, waspublished under the author
2、ityof the Board of BSI andcomes into effect on 29September1989 BSI 11-1999 First published January 1975 First revision September 1989 The following BSI references relate to the work on this standard: Committee reference CIC/25 Draft for comment87/53565 DC ISBN0 580 17074 8 Committees responsible for
3、 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 Association D
4、epartment 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 CommentsBS4258-5:1
5、989 BSI 11-1999 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 1 7 Test report 1 Publications referred to Inside back coverBS4258-5:1989 ii BSI 11-1999 Foreword This Part ofBS4258 has been prepared
6、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 This Part supersedes BS4258-5:1975, which is withdrawn, and from which it differs by making substantial reference toBS6337-2, possession o
7、f which is essential. This Part includes a procedure for the preparation of a test solution suitable for subsequent treatment and determination of silica content in accordance with the general method which reflects current practice in technique and presentation. This Part is closely related toISO336
8、1, from which it differs in the same way as fromBS4258-5:1975. 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 not of itself confer immunity fr
9、om 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 will be indicated in the amendme
10、nt table on the inside front cover.BS4258-5:1989 BSI 11-1999 1 1 Scope This Part ofBS4258 describes a method for determination of the silica content of phosphoric acid (orthophosphoric acid) for industrial use. The method is applicable to products having silica contents of not less than30mg/kg. NOTE
11、The titles of the publications referred to in this standard are listed on the inside back cover. 2 Principle The principle is described inclause3 of BS6337-2:1983. 3 Reagents The reagents described inclause4 of BS6337-2:1983 and water complying with grade1ofBS3978 are required. 4 Apparatus 4.1 Gener
12、al. The apparatus described inclause5 ofBS6337-2:1983, and the following are required. 4.2 One-mark volumetric flask,1000 mL, complying withBS1792, class B. 5 Procedure 5.1 Test portion and preparation of the test solution Weigh, to the nearest0.0001g, a test portion containing not more than1g of ph
13、osphate, expressed asP 2 O 5 . Transfer quantitatively to the volumetric flask(4.2), and dilute to the mark. Mix well. Transfer the test solution immediately to a bottle made of silica-free material. NOTEIt is recommended that reference be made to the information on sampling given inBS4258-12. 5.2 D
14、etermination Take an aliquot portion of the test solution, not exceeding15mL in volume and not containing more than2004g of silica, expressed as SiO 2 . Determine the silica content of this aliquot portion by following the procedure described inclause6 of BS6337-2:1983. 6 Calculation Calculate the m
15、ass of silica, expressed as SiO 2(in4g), in the aliquot portion of the test solution in accordance withclause7 ofBS6337-2:1983. The silica content, expressed as milligrams of silica (SiO 2 ) per kilogram, is given by the following expression: where 7 Test report The test report shall include the fol
16、lowing information: a) a complete identification of the sample; b) a reference to this British Standard, i.e.BS4258-5:1989; c) the results expressed in accordance withclause6; d) details of any unusual features noted during the determination; e) any operation not included in this British Standard or
17、 regarded as optional. m 0 is the mass of the test portion (see5.1) (ing); m 1 is the mass of SiO 2found in the aliquot portion of the test solution (see5.2) (in4g); m 2 is the mass of SiO 2found in the blank test solution (see6.2 ofBS6337-2:1983) (in4g); V is the volume of the aliquot portion (see5
18、.2) (in mL). m 1 m 2 m 0 - 1000 V - 2 blankBS4258-5:1989 BSI 11-1999 Publications referred to BS 1792, Specification for one-mark volumetric flasks. BS 3978, Specification for water for laboratory use. BS 4258, Methods of test for phosphoric acid (orthophosphoric acid) for industrial use. BS 4258-12
19、, Guide to sampling techniques. BS 6337, General methods of chemical analysis. BS 6337-2, Method for determination of silicon content (reduced molybdosilicate spectrophotometric method). ISO 3361, Phosphoric acid for industrial use Determination of silicon content Reduced molybdosilicate spectrophot
20、ometric method 1) . 1) Referred to in the foreword only.BS4258-5: 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 at the international leve
21、l. It is incorporated by Royal Charter. Revisions BritishStandards are updated by amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grat
22、eful if anyone finding an inaccuracy or ambiguity while using this BritishStandard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel:02089969000. Fax:02089967400. BSI offers members an individual updating service call
23、ed PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel:02089969001. Fax:02089967001. In response to orders for international sta
24、ndards, it is BSI policy to supply the BSI implementation of those that have been published as BritishStandards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help
25、to Exporters Service. Various BSI electronic information services are also available which give details on all its products and services. Contact the Information Centre. Tel:02089967111. Fax:02089967048. Subscribing members of BSI are kept up to date with standards developments and receive substanti
26、al discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel:02089967002. Fax:02089967001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international standa
27、rdization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, photocopying, recording or otherwise without prior written permission from BSI. This does not prec
28、lude the free use, in the course of implementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel:02089967070.
