BS 4993-1-1974 Methods of test for aluminium fluoride for industrial use - Determination of fluorine content《工业用氟化铝试验方法 第1部分 氟含量测定》.pdf
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1、BRITISH STANDARD BS4993-1: 1974 Methods of test for Aluminium fluoride for industrial use Part1: Determination of fluorine content UDC 661.862.361:546.623161:543.24:546.16BS4993-1:1974 This British Standard, having been approved by the ChemicalsIndustry StandardsCommittee, waspublished under the aut
2、horityof the Executive Boardon 28February1974 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference CIC/24 Drafts for comment/approval 71/53613 and73/50651 ISBN 0 580 08312 8 Co-operating organizations The Chemicals Industry Standards Committee, under whos
3、e supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: British Steel Industry Chemical Industries Association* Department of Health and Social Security Department of Trade and Industry Ferti
4、lizer Manufacturers Association Limited Ministry of Agriculture, Fisheries and Food National Sulphuric Acid Association Royal Institute of Public Health and Hygiene Soap and Detergent Industry Association The industrial organization marked with an asterisk in the above list, together with the follow
5、ing, were directly represented on the committee entrusted with the preparation of this British Standard: Aluminium Federation British Ceramic Research Association Society for Analytical Chemistry Society of Chemical Industry Amendments issued since publication Amd. No. Date of issue CommentsBS4993-1
6、:1974 BSI 10-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Principle 1 3 Reagents 1 4 Apparatus 2 5 Procedure 3 6 Calculation 3 Figure 1 Typical form of steam distillation apparatus for use in determination of fluorine content 4 Publications referred to I
7、nside back coverBS4993-1:1974 ii BSI 10-1999 Foreword This British Standard has been prepared under the authority of the Chemicals Industry Standards Committee in order to provide methods for the analysis of aluminium fluoride. For some years the United Kingdom has participated in the work of prepar
8、ing methods of test applicable to aluminium fluoride for industrial use, organized by Sub-Committee7 “Alumina 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
9、to publish them as parts of this British Standard. This part is based on International Standard ISO2362 “Aluminium fluoride for industrial use Determination of fluorine content Modified Willard-Winter method”, modified to take into account the comments made by the UnitedKingdom during its developmen
10、t, in particular by omitting the alternatives of spectrophotometric titration and distillation using perchloric acid. This standard prescribes methods of test only, and should be used or quoted as a specification defining limits of purity. Reference to the standard should be in a form of words indic
11、ating that the methods of test used conform to BS4993. 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
12、 obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, 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
13、 the inside front cover.BS4993-1:1974 BSI 10-1999 1 1 Scope This Part of BS4993 specifies a modified Willard-Winter method for the determination of the fluorine content of aluminium fluoride for industrial use. NOTEThe titles of the British Standards referred to in this standard are listed on the in
14、side back cover. 2 Principle A test portion is fused with sodium carbonate and the fluorine is separated by distillation with sulphuric acid. The distillate is titrated with thorium nitrate solution using as indicator either sodium alizarinsulphonate, with or without methylene blue as masking agent,
15、 or methylthymol blue. 3 Reagents The reagents used shall be of recognized analytical reagent quality. Water complying with the requirements of BS3978 shall be used throughout. 3.1 Sodium carbonate, anhydrous. 3.2 Hydrochloric acid, approximately0.06N solution. Dilute5ml of hydrochloric acid, approx
16、imately1.18g/ml, about36%(m/m) solution, with water to1000ml. 3.3 Perchloric acid, approximately N solution. 3.4 Sodium hydroxide, 20g/l solution. Dissolve20g of sodium hydroxide in water and, after cooling, dilute to1000ml. 3.5 Sulphuric acid, approximately23N. Carefully add, in small quantities,20
17、0ml of sulphuric acid, approximately1.84g/ml, about98%(m/m), to approximately100ml of water, cool and dilute to300ml. 3.6 Buffer solution, pH2.7 (for use with sodium alizarinsulphonate indicator) Dissolve9.45g of monochloroacetic acid in50ml of N sodium hydroxide solution and dilute to100ml with wat
18、er; or 3.7 Buffer solution, pH3.4 (for use with methylthymol blue indicator) Dissolve6.7g of glycine and11g of sodium perchlorate in11ml of N perchloric acid and dilute to100ml with water. 3.8 Thorium nitrate, standardized solution, approximately0.067N. 1ml of this solution is equivalent to approxim
19、ately1.3mg of fluorine. 3.8.1 Preparation of the solution. Dissolve10.01g of thorium nitrate hexahydrate Th (NO 3 ) 4 .6H 2 O in water and dilute to1000ml. 3.8.2 Standardization of the solution 3.8.2.1 Preparation of the standard reference solution. Weigh, to the nearest0.1mg, about200mg of anhydrou
20、s sodium fluoride, previously heated at600 C in a platinum dish and cooled in a desiccator. Transfer, using20ml to30ml of water, into the distillation flask(4.4.1) containing several soda-lime glass balls (2mm to3mm diameter). Stopper the distillation flask and add, through the dropping funnel(4.4.5
21、),50ml of the sulphuric acid(3.5). Carry out the distillation as described in5.3.2. Collect the distillate in a500ml one-mark volumetric flask, complying with the requirements of BS1792, dilute to the mark and mix. NOTEIf analytical reagent grade sodium fluoride is not available, recrystallize the p
22、roduct as follows. Dissolve approximately5g of pure sodium fluoride in125ml of water and, after dissolution, filter under vacuum through a small Buchner funnel. Evaporate the solution in a platinum dish down to about60ml. Cool to about50 C and separate the sodium fluoride crystals by centrifuging. W
23、ash the crystals three times by centrifuging with small quantities of cold water. Transfer the product to a platinum dish and dry in an electric oven, with natural draught, controlled at110 5 C. Remove the dish from the oven, cool in a desiccator, grind the product in an agate mortar and sieve it th
24、rough a sieve with a mesh size of0.355mm (seeBS410). Place the sieved sodium fluoride in a platinum dish, heat for2h at600 C and then allow to cool in a desiccator. 3.8.2.2 Titration. Transfer a50.0ml aliquot portion of the standard reference solution(3.8.2.1) to the beaker(4.7) and titrate as descr
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