1、BRITISH STANDARD BS3674:1981 Specification for Sodium carbonate (technical grades) UDC 661.833.622:546.33264BS3674:1981 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffect on 30
2、 November1981 BSI11-1999 First published November1963 First revision November1981 The following BSI references relate to the work on this standard: Committee reference CIC/22 Draft for comment80/53293 DC ISBN 0 580 12419 3 Cooperating organizations The Chemicals Standards Committee, under whose dire
3、ction this British Standard was prepared, consists of representatives from the following: Association of Fatty Acid Distillers British Tar Industry Association Chemical Industries Association* Chemical Society, Analytical Division Consumer Standards Advisory Committee of BSI Department of Health and
4、 Social Security Department of Industry (Laboratory of the Government Chemist) Fertiliser Manufacturers Association Ltd. Ministry of Agriculture, Fisheries and Food Ministry of Defence* National Sulphuric Acid Association Paintmakers Association of Great Britain Ltd. Royal Institute of Public Health
5、 and Hygiene Soap and Detergent Industry Association* Standardization of Tar Products Tests Committee The organizations marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Standard
6、: British Man-made Fibres Association British Textile Employers Association Fabric Care Research Association Society of Glass Technology Amendments issued since publication Amd. No. Date of issue CommentsBS3674:1981 BSI 11-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii
7、 1 Scope 1 2 References 1 3 Description 1 4 Sampling and size of sample 1 5 Material requirements 1 6 Packaging and marking 1 Table 1 Material requirements 2 Publications referred to Inside back coverBS3674:1981 ii BSI 11-1999 Foreword This British Standard, prepared under the direction of the Chemi
8、cals Standards Committee, revises the1963 edition, which is therefore withdrawn. Two specifications for sodium carbonate are given. One covers the hydrated product for use as a general household and industrial detergent, for which purposes it has the advantage over anhydrous sodium carbonate in that
9、 it dissolves easily in cold water; the other covers the anhydrous material which has a wide range of industrial applications, particularly in glass making and in the heavy chemicals industry. The standard has been revised in the light of current requirements and differs from the original publicatio
10、n in the following respects. a) The test methods are not appended to this revision but are published as Parts of BS6070. In preparing BS6070 the opportunity has been taken to implement those test methods prepared by Technical Committee47, Chemistry, of the International Organization for Standardizat
11、ion (ISO) which have been prepared as a result of international collaboration in which the United Kingdom has participated. b) The units for the specification values have been altered, where necessary, to conform with the expression of results in the associated revised test methods. A British Standa
12、rd 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 from legal obligations. Summary of pages This document comprises a front cover, a
13、n inside front cover, pagesi andii, 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 amendment table on the inside front cover.BS3674:1981 BSI 11-1999 1 1 Scope This British
14、 Standard specifies requirements for sodium carbonate decahydrate and anhydrous sodium carbonate of technical quality suitable for general industrial purposes. This standard does not apply to sodium carbonate for medical or pharmaceutical use or to a grade for photographic use. NOTEThese grades are
15、covered by the British Pharmacopoeia and BS3305 respectively. 2 References The titles of the publications referred to in this standard are listed on the inside back cover. 3 Description 3.1 Sodium carbonate decahydrate. The material shall consist essentially of sodium carbonate decahydrate, Na 2 CO
16、3 10H 2 O. It shall be in the form of almost colourless crystals which effloresce in dry air and shall be free from visible impurities. 3.2 Anhydrous sodium carbonate. The material shall consist essentially of anhydrous sodium carbonate, Na 2 CO 3 . It shall be in the form of white powder or granule
17、s and shall be free from visible impurities. NOTEThe density of commercially available material may vary, e.g.the material known in the trade as “light ash” corresponds to a pouring density of about0.5g/ml whereas that known as “heavy ash” corresponds to one of about1.0g/ml. 4 Sampling and size of s
18、ample Sampling shall be in accordance with BS6070-0. A sample size of500g is required for the purpose of examination in accordance with this specification. In the case of the anhydrous material, a total sample of2kg is required if it is necessary to determine the pouring density. 5 Material requirem
19、ents The material shall comply with the appropriate requirements of Table 1. Testing for compliance shall be carried out using the methods specified therein, with modifications, as shown in the right-hand column of the table. 6 Packaging and marking The material shall be supplied in sound, clean and
20、 dry containers. Identification and marking shall be in accordance with current legislation. BS3674:1981 2 BSI 11-1999 Table 1 Material requirements Property Sodium carbonate decahydrate Anhydrous sodium carbonate Test method BS6070: Part Particular requirements in carrying out the determination Tot
21、al soluble alkali content as Na 2 CO 3 %by mass, min. 35.9 a 97.9 b99.2 c 1 1 Matter insoluble in water%by mass, max. 0.2 0.02 4 Sulphate content as SO 4mg/kg, max. 2000 300 5 Use the following test portion: 1. Decahydrate. Prepare a4% (m/m) solution and take a5.0ml aliquot portion of this solution
22、for the determination. 2. Anhydrous material. About1.5g of the test sample, weighed to the nearest0.01g Chloride content as NaCl%by mass, max. 0.30 0.70 2 1. Use a test portion equivalent to15g of the anhydrous material, weighed to the nearest0.1g. 2. In6.2.1 of Part2:1980 add15ml (not 30ml) of the
23、nitric acid solution(4.1) to effect near-neutralization of the test solution Iron content as Femg/kg, max. 70 35 Test method to be agreed by purchaser and supplier pending publication and implementation as a British Standard, of the ISO general method (1,10-phenanthroline) for determination of iron
24、content Copper content, as Cumg/kg, max. Not specified 4 7 Pouring density g/ml Not specified Subject to agreement between purchaser and supplier 6 a Sodium carbonate decahydrate (soda crystals) tends to lose moisture by efflorescence of the crystals. This may result in the material as delivered or
25、as used having a higher sodium carbonate content than at the time of manufacture. b This requirement is for the anhydrous materials at the time of packing. Material containing lower than97.9% of Na 2 CO 3at the time of delivery shall, however, be deemed to comply with the requirements of this standa
26、rd provided that the difference from97.9% is due solely to the uptake of moisture and carbon dioxide. This requirement is satisfied if the Na 2 CO 3content of the material delivered, multiplied by the mass of material delivered and divided by the mass of material invoiced, is not lower than97.9%. Al
27、ternatively, if required by the purchaser, the material shall, at the time of delivery, contain not lower than94.0% of Na 2 CO 3 . c This determination is carried out on material that has been heated for1h in an electrically-heated oven or an electrically-heated muffle furnace controlled at250 C to3
28、00 C.BS3674:1981 BSI 11-1999 Publications referred to BS3305, Specification for photographic grade sodium carbonate, anhydrous. BS6070, Methods of sampling and test for sodium carbonate for industrial use. BS6070-0, General introduction. BS6070-1, Determination of total soluble alkali content. BS607
29、0-2, Determination of chloride content. BS6070-4, Determination of matter insoluble in water. BS6070-5, Determination of sulphate content. BS6070-6, Determination of pouring density. BS6070-7, Determination of copper content. BS3674:1981 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsIn
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