1、BRITISH STANDARD BS 6070-1: 1981 ISO 740:1976 Methods of Sampling and test for sodium carbonate for industrial use Part 1: Determination of total soluble alkali content ISO title: Sodium carbonate for industrial use Determination of total soluble alkalinity Titrimetric method NOTEIt is recommended t
2、hat this Part be read in conjunction with the information in the “General introduction” published separately as BS6070-0. UDC 661.833.622:546.33264:543.241.2BS6070-1:1981 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the auth
3、orityofthe Executive Boardand comes into effect on 27 February1981 BSI 12-1999 The following BSI reference relates to the work on this standard: Committee reference CIC/22 ISBN 0 580 11899 1 National foreword This Part of BS 6070 is identical with ISO740 “Sodium carbonate for industrial use Determin
4、ation of total soluble alkalinity Titrimetric method” published in1976 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 terminol
5、ogy and certain conventions are not identical with those 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
6、the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. There is no British Standard corresponding directly to ISO739 to which reference is made in6.1. Technically equivalent information is given in BS6070-0. The standards listed in the Annex
7、 are intended for information only. Corresponding British Standards are listed in BS6070-0. Additional information. Water. Water complying with the requirements of clause4 is specified in BS3978 “Water for laboratory use”. A British Standard does not purport to include all the necessary provisions o
8、f a contract. Users of British Standards are responsible 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 insid
9、e 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 table on the inside front cover. Cross-references International Standard Corresponding British Standard ISO 745:1976 BS 6070 Methods of
10、 sampling and test for sodium carbonate for industrial use Part 3:1981 Determination of non-volatile matter (Identical) Amendments issued since publication Amd. No. Date of issue CommentsBS6070-1:1981 BSI 12-1999 i Contents Page National foreword Inside front cover 1 Scope and field of application 1
11、 2 References 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Procedure 1 7 Expression of results 1 8 Test report 1 Annex ISO publication relating to sodium carbonate for industrial use 2 Publications referred to Inside back coverii blankBS6070-1:1981 BSI 12-1999 1 1 Scope and field of application This
12、 International Standard specifies a titrimetric method for the determination of the total soluble alkalinity of sodium carbonate for industrial use. 2 References ISO 739, Sodium carbonate for industrial use Preparation and storage of test samples. ISO 745, Sodium carbonate for industrial use Determi
13、nation of loss of mass and of non-volatile matter at250 C. 3 Principle Solution of a test portion, filtration of the solution and titration of the total soluble alkalinity with a standard volumetric solution of hydrochloric acid, using methyl orange as indicator. 4 Reagents During the analysis, use
14、only reagents of recognized analytical reagent grade and only distilled water or water of equivalent purity. 4.1 Hydrochloric acid, 1 N standard volumetric solution. 4.2 Methyl orange, 0,5 g/l solution. NOTEThe methyl orange may be replaced by any other indicator giving the same end-point. 5 Apparat
15、us Ordinary laboratory apparatus. 6 Procedure 6.1 Test portion Weigh, to the nearest0,01g, a mass of the testsample (see ISO739) of50 0,1g, 59 0,1g, 110 0,1g or 135 0,1g, depending on whether the product is anhydrous or mono-, hepta- or decahydrate. 6.2 Preparation of test solution Dissolve the test
16、 portion (6.1) by pouring it in small quantities at a time, while stirring, into a beaker of suitable capacity (for example600ml) containing200ml of water at about50 C. Filter the decanted solution through a medium-speed filter, collecting the filtrate in a500ml one-mark volumetric flask. Wash the i
17、nsoluble matter onto the filter with water at about50 C. Complete the washing, collecting all the washings in the volumetric flask. Allow to cool, dilute to the mark and mix. 6.3 Titration Transfer 25,0 ml of the test solution (6.2) to a500ml conical flask. Add approximately75ml of water,5drops of t
18、he methyl orange solution (4.2) and titrate with the standard volumetric hydrochloric acid solution (4.1) until the indicator turns from yellow to orange-pink. NOTEIf required, this determination may also be carried out by means of back-titration, using1N standard volumetric hydrochloric acid soluti
19、on and1N or0,1N standard volumetric sodium hydroxide solution. If this method is adopted, it shall be taken into account in the calculation of results. 7 Expression of results The total soluble alkalinity, expressed as a percentage by mass of sodium carbonate (Na 2 CO 3 ), is given by the formula: w
20、here V is the volume, in millilitres, of the standard volumetric hydrochloric acid solution (4.1) used for the titration; m is the mass, in grams, of the test portion(6.1); 0,053 0 is the mass, in grams, of sodium carbonate equivalent to1ml of exactly1N standard volumetric hydrochloric acid solution
21、. NOTE 1If the concentration of the standard volumetric solution used is not exactly as specified in the list of reagents, an appropriate correction should be made. NOTE 2If it is desired to express the result on the basis of non-volatile matter at250 C (see ISO745), multiply the result obtained on
22、the product as received by the ratio 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; c) any unusual features noted during the determination. d) any operation not included in this Internation
23、al Standard or in the International Standards to which reference is made, or regarded as optional. 100 100 loss of mass at 250 C in% (m/m)BS6070-1:1981 2 BSI 12-1999 Annex ISO publications relating to sodium carbonate for industrial use ISO 739, Preparation and storage of test samples. ISO 740, Dete
24、rmination of total soluble alkalinity Titrimetric method. ISO 741, Determination of sodium hydrogen carbonate content Titrimetric method. ISO 742, Determination of chloride content Mercurimetric method. ISO 743, Determination of sulphate content Barium sulphate gravimetric method. ISO 744, Determina
25、tion of iron content 1,10-Phenanthroline photometric method. ISO 745, Determination of loss of mass and of non-volatile matter at250 C. ISO 746, Determination of matter insoluble in water at 50 C. BS6070-1:1981 BSI 12-1999 Publications referred to See national foreword.BS 6070-1: 1981 ISO 740:1976 B
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