1、BRITISH STANDARD BS 5072-7: 1980 ISO 3431: 1976 Methods of Test for sodium fluoride for industrial use Part 7: Determination of soluble sulphates content ISO title: Sodium fluoride primarily used for the production ofaluminium Determination of soluble sulphates content Turbidimetric method UDC 661.8
2、33.361:546.33161:543.436.062:546.226BS5072-7:1980 This British Standard, having been prepared under the directionof the Chemicals Standards Committee, was published under the authority ofthe Executive Board and comesinto effect on 30 April 1980 BSI 12-1999 The following BSI references relate to the
3、work on this standard: Committee reference CIC/24 Draft for comment 74/54500 DC ISBN 0 580 11218 7 Cooperating organizations The Chemicals Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government departments and scientif
4、ic and industrial organizations: 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 Social Security Department of Industry (Laboratory of t
5、he Government Chemist) Fertiliser Manufacturers Association Ltd Hydrocarbon Solvents Association Ministry of Agriculture, Fisheries and Food Ministry of Defence National Sulphuric Acid Association Paintmakers Association of Great Britain Ltd Royal Institute of Public Health and Hygiene Soap and Dete
6、rgent 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 committee entrusted with the preparation of this British Standard: Aluminium Federation British Cerami
7、c Research Association Royal Institute of Chemistry Amendments issued since publication Amd. No. Date of issue CommentsBS5072-7:1980 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii 1 Scope and field of application 1 2 Reference 1 3 Principle 1 4 Reagents
8、 1 5 Apparatus 1 6 Procedure 1 7 Expression of results 2 8 Test report 2 Annex ISO Publications relating to sodium fluoride for industrial use and sodium fluoride primarily used for the productionofaluminium 3 Publications referred to Inside back coverBS5072-7:1980 ii BSI 12-1999 National foreword W
9、ARNING NOTE. Sodium fluoride is toxic and is irritant, particularly in the form of dust. Carry out operations involving its use in a fume cupboard and wear suitable protective clothing to prevent inhalation of the dust and contact with the eyes, skin and clothing. This British Standard has been prep
10、ared under the direction of the Chemicals Standards Committee in order to provide methods for the analysis of sodium fluoride for industrial use. For some years the UnitedKingdom has participated in the work of preparing methods of test applicable to this material, organized by Subcommittee7 (former
11、ly WG8), Aluminium oxide and related compounds, of Technical Committee47, Chemistry, of the International Organization for Standardization (ISO). As international agreement is reached on the methods, it is proposed to publish them as Parts of this British Standard. This Part is identical with ISO343
12、1 “Sodium fluoride primarily used for the production of aluminium Determination of soluble sulphates content Turbidimetric method”. Terminology and conventions. The text of the International Standard has been approved as suitable for publication, without deviation, as a British Standard. Some termin
13、ology 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. Where
14、the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Related British Standards for ISO2831 1) , ISO2832 1)and ISO2833 1)are BS5072-1, BS5072-2 and BS5072-3 respectively. NOTEThe title and clause1 of ISO3429, ISO3430, ISO3431, ISO3566 and I
15、SO4278 (seetheAnnex) state that the sodium fluoride is “primarily used for the production of aluminium”. This is incorrect, at least for the UnitedKingdom. This has been brought to the attention of ISO Technical Committee47, in a proposal to amend the International Standards concerned. Additional in
16、formation Water. Water complying with the requirements of clause4 is specified in BS3978 “Water for laboratory use”. Hydrochloric acid, approximately 1.18g/ml, about36% (m/m) solution, which is the corresponding reagent normally obtainable in the UnitedKingdom, is suitable for use in place of the ap
17、proximately 1.19g/ml solution specified in4.1. Cross-references International Standard Corresponding British Standard BS 5072 Methods of test for sodium fluoride for industrial use ISO 3428:1976 Part 4:1980 Preparation and storage of test samples (Identical) ISO 3429:1976 Part 5:1980 Determination o
18、f iron content (Identical) ISO 3430:1976 Part 6:1980 Determination of silica content (Identical) ISO 3566:1976 Part 8:1980 Determination of chlorides content (Identical) ISO 4278:1977 Part 9:1980 Determination of carbonate content (Identical) Referred to in theAnnex, for information only. 1) Referre
19、d to in theAnnex, for information only.BS5072-7:1980 BSI 12-1999 iii This standard prescribes methods of test only, and should not be used or quotedas a specification defining limits of purity. Reference to the standard should indicate that the methods of test used comply with the requirements ofBS5
20、072-7. 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 from legal obligations. Summary of pages This document com
21、prises a front cover, an inside front cover, pagesi toiv, pages1to4, 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.iv blankBS5072-7:1980 BSI
22、12-1999 1 1 Scope and field of application This International Standard specifies a turbidimetric method for the determination of the soluble sulphates content of sodium fluoride primarily used for the production of aluminium. The method is applicable to products of which the soluble sulphates conten
23、t, expressed as SO 4 , is greater than0,05% (m/m). 2 Reference ISO 3428, Sodium fluoride for industrial use Preparation and storage of test samples. 3 Principle Evaporation of a test portion, in hydrochloric acid solution, to dryness and dissolution of the residue in a hydrochloric acid solution. Me
24、asurement of the turbidity obtained by precipitation, under well-defined conditions, of barium sulphate. 4 Reagents During the analysis, use only reagents of recognized analytical grade, and only distilled water, or water of equivalent purity. 4.1 Hydrochloric acid, approximately 1,19g/ml, about 38%
25、 (m/m) solution or approximately12N. 4.2 Barium chloride dihydrate, of uniform particle size between0,50 and1,25mm, standardized by screening. It is essential that all preparations concerning the determination and standardization shall be carried out using a product of the same particle size distrib
26、ution. 4.3 Hydrochloric acid, approximately1N solution. 4.4 Sulphuric acid, standard solution, corresponding to0,200g of SO 4per litre. Introduce 41,60 ml of 0,1N standard volumetric sulphuric acid solution into a1000ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this standard sol
27、ution contains0,2mg ofSO 4 . 4.5 Glycerol 4.6 Sodium chloride, 240 g/l acid solution. Dissolve 120g of sodium chloride in 450ml of water in a500ml one-mark volumetric flask. Add10ml of the hydrochloric acid solution (4.1). Dilute to the mark and mix. 5 Apparatus Ordinary laboratory apparatus and: 5.
28、1 Spectrophotometer, or 5.2 Photoelectric absorptiometer, fitted with filters giving only a negligible transmission below450nm and above550nm. 6 Procedure 6.1 Test portion Weigh, to the nearest 0,01g, 2 0,1g of the dried test sample (see ISO3428, sub-clause2.3). 6.2 Blank test Carry out a blank test
29、 at the same time as the determination, following the same procedure and using the same quantities of all the reagents as usedfor the determination, but replacing the test portion by2,5ml of the standard sulphuric acid solution (4.4), corresponding to0,5mg of SO 4 , added in order to operate in the
30、linear part of the calibration curve. 6.3 Preparation of calibration graph 6.3.1 Preparation of the standard matching solutions Into each of a series of nine50ml one-mark volumetric flasks, place the volumes of the standard sulphuric acid solution (4.4) indicated in the following table. Add to each
31、flask 5ml of the hydrochloric acid solution (4.3), 10ml of the glycerol (4.5) and10ml of the acid sodium chloride solution (4.6), stir, dilute to the mark and mix. Standard sulphuric acid solution (4.4) Corresponding mass of SO 4 ml mg 0 a 2,5 5,0 7,5 10,0 12,5 15,0 17,5 20,0 0 0,5 1,0 1,5 2,0 2,5 3
32、,0 3,5 4,0 a Compensation solution.BS5072-7:1980 2 BSI 12-1999 6.3.2 Turbidimetric reaction Transfer 25,0ml of each standard matching solution (6.3.1), with the exception of the first, to a series of dry100ml beakers each containing0,15g of the barium chloride (4.2). Swirl by hand for1min at a rate
33、of2revolutions per second. By this time, the barium chloride should be completely dissolved. Allow to stand for20min at a temperature of20 2 C. NOTEStagger the tests in order to adhere to the contact times indicated. 6.3.3 Turbidimetric measurements Carry out the turbidimetric measurements usingthe
34、spectrophotometer (5.1), at a wavelengthof about470nm, or the photoelectric absorptiometer (5.2), fitted with appropriate filters, after having adjusted the instrument to the optical zero against the compensation solution. Use cells of suitable path length. NOTEStir the solutions by hand before intr
35、oducing in the cells. 6.3.4 Preparation of graph Plot a graph having, for example, the sulphate contents, expressed as milligrams of SO 4in the total quantity (50ml) of the standard matching solutions, as abscissae and the corresponding values of measurements as ordinates. NOTEThe calibration curve
36、is linear only above0,5mg of SO 4 . 6.4 Determination 6.4.1 Preparation of the test solution Introduce the test portion (6.1) into a platinum dish of suitable capacity. Add20ml of the hydrochloric acid solution (4.1) and evaporate to dryness on a boiling water bath. Repeat this treatment four times.
37、 Dissolve the residue in 5ml of the hydrochloric acid solution (4.3) and20ml of water. Heat for several minutes on a boiling water bath, allow to cool, transfer quantitatively to a50ml one-mark volumetric flask, add2,5ml of the standard sulphuric acid solution (4.4), corresponding to0,5mg of SO 4 ,
38、added in order to operate in the linear portion of the calibration curve, 10ml of the glycerol (4.5) and10ml of the acid sodium chloride solution (4.6), dilute to the mark and mix. If the solution is turbid, filter on a dry filter collecting the filtrate in a dry receiver. 6.4.2 Turbidimetric reacti
39、on Transfer 25,0 ml of the test solution (6.4.1) rapidly to a dry100ml beaker containing0,15g of the barium chloride (4.2). Swirl by hand, for1min, at a rate of2 revolutions per second. By this time the barium chloride should be completely dissolved. Allow to stand for20min at a temperature of20 2 C
40、. 6.4.3 Turbidimetric measurement Carry out the turbidimetric measurement by the procedure specified in6.3.3 after having adjusted the instrument to optical zero against the test solution (6.4.1) and using a cell of the same path length. NOTEIf the reaction leads to turbidity beyond the limit of the
41、calibration graph, dilute an aliquot portion of the test solution (6.4.1) to50ml, after having added the necessary volumes of the glycerol (4.5) and the acid sodium chloride solution (4.6). Then carry out the determination using25,0ml of this diluted solution. In this case use this latter as compens
42、ation solution and take account of this additional dilution in the calculation of the result. 7 Expression of results By means of the calibration graph (6.3.4), determine the quantity of sulphate (SO 4 ) corresponding to the value of the turbidimetric measurement. The sulphate content, expressed as
43、a percentage by mass of SO 4 , is given by the formula where m 0 is the mass, in grams, of the test portion(6.1); m 1 is the mass, in milligrams, of sulphate found in the total quantity (50ml) of the test solution (6.4.1); m 2 is the mass, in milligrams, of sulphate found in the total quantity (50ml
44、) of the blank test solution (6.2). 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 Internationa
45、l Standard, or in the International Standard to which reference is made, or regarded as optional. m 1 m 2 () 1 1 000 - 100 m 0 - m 1 m 2 10 m 0 - =BS5072-7:1980 BSI 12-1999 3 Annex ISO Publications relating to sodium fluoride for industrial use and sodium fluoride primarily used for the production o
46、f aluminium Sodium fluoride for industrial use ISO 2831, Determination of water-insoluble matter. ISO 2832, Determination of moisture content. ISO 2833, Determination of fluorine content Modified Willard-Winter method. ISO 3428, Preparation and storage of test samples. Sodium fluoride primarily used
47、 for the production of aluminium ISO 3429, Determination of iron content 1,10-Phenanthroline photometric method. ISO 3430, Determination of silica content Reduced molybdosilicate spectrophotometric method. ISO 3431, Determination of soluble sulphates content Turbidimetric method. ISO 3566, Determina
48、tion of chlorides content Turbidimetric method. ISO 4278, Determination of carbonates content Gravimetric method.4 blankBS5072-7:1980 BSI 12-1999 Publications referred to See national foreword.BS 5072-7: 1980 ISO 3431: 1976 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI
49、is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. 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 grateful if anyone finding an inaccuracy o
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