1、BRITISH STANDARD BS 6075-1: 1981 ISO 979:1974 Methods of Sampling and test for sodium hydroxide for industrial use Part 1: Determination of sodium hydroxide content ISO title: Sodium hydroxide for industrial use Method of assay NOTEIt is recommended that this Part be read in conjunction with the inf
2、ormation in the “General introduction” published separately as BS 6075-0. UDC 661.322.1:546.33 36:543.79:543.241.2BS6075-1:1981 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authority ofthe Executive Board and comesinto e
3、ffect on 27February1981 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference CIC/22 Draft for comment 73/54863 DC ISBN 0 580 12051 1 National foreword This Part of BS 6075 is identical with ISO 979 “Sodium hydroxide for industrial use Method of assay”, pu
4、blished in 1974 by the International Organization for Standardization (ISO). Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with thos
5、e used in British Standards; attention is especially drawn to the following. The comma has been used throughout as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to
6、 this standard, they should be read as “British Standard”. 50 ml, class A pipettes complying with the requirements of BS 1583:1961 “One-mark pipettes” and 50 ml burettes, class A complying with the requirements of BS 846:1980 “Burettes and bulb burettes”, are technically equivalent to the apparatus
7、specified in 5.1 and 5.2, respectively. Additional information Water. Water complying with the requirements of clause 4 is specified in BS3978 “Water for laboratory use”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are respons
8、ible 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 cover, an inside front cover, pages i and ii, pages 1 and 2, an inside back cover and a back cover. This standard has bee
9、n updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Cross-references International Standard Corresponding British Standard BS 6075 Methods of sampling and test for sodium hydroxide for industrial use ISO 31
10、95:1975 Part 5:1981 Sampling and preparation of main test solution (Identical) ISO 3196:1975 Part 6:1981 Determination of carbonate content (Identical) Amendments issued since publication Amd. No. Date of issue CommentsBS6075-1:1981 BSI 10-1999 i Contents Page National foreword Inside front cover 1
11、Scope and field of application 1 2 References 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Procedure 1 7 Expression of results 1 8 Test report 1 Publications referred to Inside back coverii blankBS6075-1:1981 BSI 10-1999 1 1 Scope and field of application This International Standard specifies a meth
12、od of assay of sodium hydroxide for industrial use. This assay can be expressed conventionally, as percentages by mass of NaOH, in two different ways: A total alkalinity (NaOH equiv.); B caustic alkalinity (NaOH c.), corresponding to the total alkalinity less the alkalinity due to carbonates. 2 Refe
13、rences ISO 3195, Sodium hydroxide for industrial use Sampling Test sample Preparation of the main solution for carrying out certain determinations 1) . ISO 3196, Sodium hydroxide for industrial use Determination of carbonates content Titrimetric method 1) . 3 Principle Titration of the total alkalin
14、ity with standard volumetric hydrochloric acid solution in the presence of methyl orange as indicator. Calculation of the two amounts A and B defined in clause 1. 4 Reagents During the analysis, use only reagents of recognized analytical reagent grade, and only distilled water or water of equivalent
15、 purity. 4.1 Hydrochloric acid, N standard volumetric solution. 4.2 Methyl orange, 0,5 g/l solution. 5 Apparatus Ordinary laboratory apparatus and 5.1 Pipette, 50 ml, accurate to 0,05 ml (see ISO/R 648, class A). 5.2 Burette, 50 ml (see ISO/R 385, class A), with tapered jet, permitting a delivery of
16、 about 30 drops per millilitre. 6 Procedure 6.1 Test portion Transfer 50,0 ml of the main solution A 2), by means of the pipette (5.1), to a 500 ml conical flask. 6.2 Titration Add about 50 ml of water and 5 drops of the methyl orange solution (4.2) to the conical flask containing the test portion (
17、6.1) and titrate with the standard volumetric hydrochloric acid solution (4.1) contained in the burette (5.2) until the colour changes from yellow to orange. 7 Expression of results 7.1 Total alkalinity (NaOH equiv.) The total alkalinity (A), expressed as a percentage by mass of sodium hydroxide (Na
18、OH), is given by the formula where The result should be expressed to one decimal place. 7.2 Caustic alkalinity (NaOH c.) The caustic alkalinity (B), expressed as a percentage by mass of sodium hydroxide (NaOH), is given by the formula B = A 1,818 b where The results should be expressed to one decima
19、l place. 8 Test report The test report shall include the following particulars: a) the reference of the method used; b) the results and the method of expression used; 1) At present at the stage of draft. 2) See 4.3 of ISO 3195. V is the volume, in millilitres, of the standard volumetric hydrochloric
20、 acid solution (4.1) used for the titration; m is the mass, in grams, of the test portion used for the preparation of the main solutionA a . a See 4.3 of ISO 3195. A is the total alkalinity (7.1), expressed as a percentage by mass of sodium hydroxide (NaOH); b is the carbonates content, expressed as
21、 a percentage by mass of carbon dioxide (CO 2 ) determined by the method specified in ISO 3196; 1,818 is the conversion factor of CO 2to 2NaOH. AV 1000 50 - 100 m - 004000 , 80 V m - =BS6075-1:1981 2 BSI 10-1999 c) any unusual features noted during the determination; d) any operation not included in
22、 this International Standard or the International Standards to which reference is made, or regarded as optional.BS6075-1:1981 BSI 10-1999 Publications referred to See national foreword.BS 6075-1: 1981 ISO 979:1974 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the ind
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