1、BRITISH STANDARD BS5634:1978 Methods of test for Potassium hydroxide UDC 661.832.23:546.3236:543.062BS5634:1978 This BritishStandard, having been prepared under the directionof the Chemicals Standards Committee, waspublished under the authorityofthe Executive Boardon 29 December1978 BSI12-1999 The f
2、ollowing BSI references relate to the work on this standard: Committee reference CIC/22 Draft for comment75/52128DC ISBN 0 580 10378 1 Cooperating organizations The Chemicals Standards Committee, under whose direction this BritishStandard was prepared, consists of representatives from the following
3、Government departments and scientific and industrial organizations: Association of Fatty Acid Distillers British Tar Industry Association Chemical Industries Association* Department of Health and Social Security Department of Industry, Laboratory of the Government Chemist Fertiliser Manufacturers As
4、sociation 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 Detergent Industry Association* Society for Analytic
5、al Chemistry 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 BritishStandard: Asbestos Cement Manufacturers Association British
6、Man-made Fibres Federation British Textile Employers Association Fabric Care Research Association Society of Glass Technology Amendments issued since publication Amd. No. Date of issue CommentsBS5634:1978 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii Section 1.
7、 General 1 Scope 1 2 References 1 3 Preparation of sample solution 1 Section 2. Methods of test 4 Determination of total hydroxide content 1 5 Determination of carbonate content 2 6 Determination of sodium content 4 7 Determination of chloride content 5 8 Determination of content of sulphur compound
8、s 7 9 Determination of nitrate content 9 10 Determination of cyanide content 11 11 Determination of silica content 12 12 Determination of calcium content 14 13 Determination of iron content 17 14 Determination of zinc content 18 15 Determination of copper content 20 16 Determination of lead content
9、21 17 Determination of nickel content 23 18 Determination of arsenic content 24 Figure 1 Typical apparatus for the determination of carbonate content 3 Figure 2 Typical apparatus for the determination of content of sulphur compounds 8 Figure 3 Typical apparatus for the preparation of the reducing so
10、lution(8.3.7) used in the determination of content of sulphur compounds 9 Publications referred to Inside back coverBS5634:1978 ii BSI 12-1999 Foreword This BritishStandard, prepared under the direction of the Chemicals Standards Committee, comprises methods of test for potassium hydroxide in solid
11、form and in aqueous solution. It provides a full range of tests for use in conjunction with BS5633, which specifies potassium hydroxide for use in alkaline cells. Not all of these tests may be necessary when testing potassium hydroxide for other industrial uses (in such cases the methods may be used
12、 selectively). The opportunity has been taken, where appropriate, to incorporate substantially the technical content of International Standards from the series of methods of test for potassium hydroxide for industrial use which has been prepared, with the active participation of the UnitedKingdom, b
13、y Sub-committee5 of Technical Committee47, Chemistry, of the International Organization for Standardization (ISO). The relationship between the appropriate BritishStandard methods and the International Standards is shown in the table below. The method of ISO2466 has been modified by the introduction
14、 of two sample solutions, one a solution of the sample corresponding to solution A in ISO2466 and the other an acidified solution of the sample, designated solution B. A third solution, designated C, is a blank for the acid used in the preparation of solutionB. If it is necessary to determine all th
15、e trace metals, the use of solutionB results in considerable saving of time. The procedure used for the determination of arsenic, which is the same as that described in BS4404, is technically similar to the method given in ISO2590. Atomic absorption methods are described for the determinations of ca
16、lcium, zinc and lead. The flame emission photometric method used for the determination of sodium is similar in principle to that described in ISO1550 but, in accordance with UnitedKingdom comments not accepted by the ISO committee, does not restrict the fuel for the atomizer-burner of the flame spec
17、trophotometer to a butane/air mixture. Other International Standards in the series of methods of test for potassium hydroxide for industrial use will be published as addenda to this British Standard, subject to their approval by the UnitedKingdom. There are at present no ISO methods for the determin
18、ation of the contents of nitrate, cyanide, zinc, copper, lead and nickel in potassium hydroxide. BS5634: Preparation/ Determination of Corresponding International Standard sample solutions total hydroxide content carbonate content chloride content content of sulphur compounds silica content ISO2466,
19、 “Potassium hydroxide for industrial use Sampling Test sample Preparation of the main solution for carrying out certain determinations” ISO990, “Potassium hydroxide for industrial use Method of assay” ISO2900, “Potassium hydroxide for industrial use Determination of carbon dioxide content Titrimetri
20、c method” ISO3177, “Potassium hydroxide for industrial use Determination of chlorides content Photometric method” ISO3194, “Potassium hydroxide for industrial use Determination of sulphur compounds Method by reduction and titrimetry” ISO995, “Potassium hydroxide for industrial use Determination of s
21、ilica content Reduced molybdosilicate photometric method”BS5634:1978 BSI 12-1999 iii 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 its
22、elf confer immunity from legal obligations. BS5634: Preparation/ Determination of Corresponding International Standard calcium content iron content ISO3698, “Potassium hydroxide for industrial use Determination of calcium and magnesium contents Flame atomic absorption method” ISO994, “Potassium hydr
23、oxide for industrial use Determination of iron content 1,10-Phenanthroline photometric method” Summary of pages This document comprises a front cover, an inside front cover, pagesi to iv, pages1to26, an inside back cover and a back cover. This standard has been updated (see copyright date) and may h
24、ave had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS5634:1978 BSI 12-1999 1 Section 1. General 1 Scope This BritishStandard specifies methods for sampling and testing potassium hydroxide in solid form and in aqueous solution. 2 Reference
25、s The titles of the publications referred to in this standard are listed on the inside back cover. 3 Preparation of sample solution 3.1 Principle. Three solutions are prepared, solution A which is a solution of the sample in water, solution B which is an acidified solution of the sample in water and
26、 solution C which is a blank for the acid used in preparing solution B. NOTEThe use of these bulk sample solutions serves to reduce sampling errors. In the case of solution B, acidification ensures dissolution of metallic impurities and allows more uniform sampling for the determination of metallic
27、impurities. 3.2 Reagents. The reagents used shall be of recognized analytical quality. Water complying with the requirements of BS3978 shall be used throughout. 3.2.1 Hydrochloric acid, approximately5N solution. 3.2.2 Methyl orange indicator solution, 0.4g/l, prepared as described in BS4123. 3.3 App
28、aratus. Ordinary laboratory apparatus is required. 3.4 Procedure 3.4.1 Preliminary treatment of sample. Protect the laboratory sample from the atmosphere and handle it in such a way that no appreciable absorption of moisture or carbon dioxide or reaction with silica can occur. The maximum particle s
29、ize of solid test portions shall not exceed about6mm. If crushing is necessary, carry it out as quickly as possible, in as inert an atmosphere as possible, preferably in an unventilated glove box containing evenly-distributed shallow dishes of phosphorus (V) oxide and similar dishes of potassium hyd
30、roxide pellets to remove water vapour and carbon dioxide, respectively. These absorbents should be left in the glove box for at least1h before it is used. 3.4.2 Preparation of solution A. Weigh, accurately,100 1g of the solid sample or200 2g of the liquid sample into an alkali-resistant container fi
31、tted with a lid. If the sample is solid, dissolve it in250ml of freshly boiled and cooled water in an alkali-resistant beaker and cool. Transfer the solution, or the original sample if liquid, to a500ml alkali-resistant graduated cylinder, dilute to the mark with water, mix and transfer immediately
32、to an airtight, alkali-resistant plastics bottle. Label as “Solution A”. 3.4.3 Preparation of solution B. Weigh10.0 0.1g of the solid sample, or20.0 0.2g of the liquid sample, into a250ml beaker. Add50ml of water, swirl to dissolve or mix, and titrate with the hydrochloric acid solution(3.2.1) using
33、 the methyl orange solution(3.2.2) as indicator. Let the titration be X ml. Discard the solution. Weigh, accurately,100 1g of the solid sample or200 2g of the liquid sample into a1000ml beaker. Add200ml of water and swirl to dissolve or mix. From a measuring cylinder cautiously add(10 X +5)ml of the
34、 hydrochloric acid solution(3.2.1) with continuous stirring. Cool the contents of the beaker to ambient temperature, transfer to a1000ml one-mark volumetric flask, dilute to the mark with water and mix. Label as “Solution B”. 3.4.4 Preparation of solution C. Evaporate(10X +5)ml (see3.4.3) of the hyd
35、rochloric acid solution(3.2.1) to5ml in a1000ml beaker, taking care to avoid contamination. Transfer the residual solution quantitatively to a1000ml one-mark volumetric flask, dilute to the mark with water and mix. Label as “Solution C”. Section 2. Methods of test 4 Determination of total hydroxide
36、content 4.1 Field of application. The method is applicable to all commercial products, both solid and liquid. 4.2 Principle. The total alkalinity content is determined by titration with hydrochloric acid solution using methyl orange as indicator and a correction is made for the carbonate content, de
37、termined by the method of test specified in clause5, to give total hydroxide content. 4.3 Reagents. The reagents used shall be of recognized analytical quality. Water complying with the requirements of BS3978, freshly boiled to free it from carbon dioxide, shall be used throughout. 4.3.1 Hydrochlori
38、c acid, 1N standard volumetric solution.BS5634:1978 2 BSI 12-1999 4.3.2 Methyl orange indicator solution, 0.4g/l, prepared as described in BS4123. 4.4 Apparatus. Ordinary laboratory apparatus and the following are required. 4.4.1 Burette, 50ml capacity, complying with the requirements for class A of
39、 BS846. 4.5 Procedure. Weigh, to the nearest0.01g,25g of the solid sample or50g of the liquid sample. Dissolve in or mix with200ml of water in a400ml beaker. Cool and transfer to a500ml one-mark volumetric flask, dilute to the mark with water and mix. Pipette50.0ml of this solution into a500ml conic
40、al flask. Add80ml of water and five drops of the methyl orange solution(4.3.2) and titrate with the hydrochloric solution(4.3.1) until the colour changes from yellow to orange. 4.6 Expression of results. The total hydroxide content, expressed as the percentage by mass of potassium hydroxide (KOH), i
41、s given by the following formula: 5 Determination of carbonate content 5.1 Field of application. The method is applicable to products having carbonate contents, expressed as potassium carbonate (K 2 CO 3 ), greater than0.02% m/m. 5.2 Principle. Carbon dioxide is released by acidifying and heating th
42、e test solution. The released carbon dioxide is entrained in a current of nitrogen or air and absorbed in standard barium hydroxide solution. The excess barium hydroxide is titrated with a standard volumetric solution of hydrochloric acid using thymolphthalein as indicator. 5.3 Reagents. The reagent
43、s used shall be of recognized analytical quality. Water complying with the requirements of BS3978 shall be used throughout. 5.3.1 Hydrochloric acid, approximately5N solution. 5.3.2 Hydrochloric acid, 0.1N standard volumetric solution. 5.3.3 Barium hydroxide, approximately0.1N solution. Weigh15 0.1g
44、of barium hydroxide octahydrate, Ba(OH) 2 .8H 2 O, dissolve in water, dilute to1000ml and mix. Allow precipitated barium carbonate to settle out before use. 5.3.4 Methyl orange indicator solution, 0.4g/l, prepared as described in BS4123. 5.3.5 Thymolphthalein indicator solution, 2g/l, prepared as de
45、scribed in BS4123. 5.3.6 Nitrogen or air, free from carbon dioxide. 5.4 Apparatus. Ordinary laboratory apparatus and the following are required. 5.4.1 Apparatus for the release, absorption and titration of carbon dioxide. A typical apparatus, shown in Figure 1, comprises 5.5 Procedure 5.5.1 Test por
46、tion. Measure out a volume of the solution A(3.4.2) containing not more than25g of potassium hydroxide or150mg of potassium carbonate. 5.5.2 Blank test. Subsequent to the determination, carry out a blank test following the procedure specified in5.5.3 but omitting the test portion. where V is the vol
47、ume of the hydrochloric acid solution(4.3.1) used in the determination of total alkali (inml) m is the mass of the test portion (ing) A is the carbonate content of the sample, expressed as the percentage by mass of potassium carbonate (K 2 CO 3 ) (see clause5) A flask,500ml capacity B dropping funne
48、l,100ml capacity C 1and C 2 Drechsel bottles, containing 20% m/m sodium hydroxide solution C 3 Drechsel bottle, containing saturated barium hydroxide solution D spiral condenser E absorption vessel F absorption coil, made from glass tubing of diameter7mm to8mm and consisting of five or six turns of
49、diameter55mm to60mm G burette,50ml capacity, complying with the requirements for class A of BS846 H stopcock J inlet for nitrogen or air (free from carbon dioxide) K outlet for nitrogen or air (free from carbon dioxide) L mercury lute fitted with guard tube containing activated charcoalBS5634:1978 BSI 12-1999 3 5.5.3 Determination. Pass the nitrogen or the air(5.3.6) through the apparatus at a rate of about5 bubbles per second for10min. Stop the current of gas and introduce the test portions and reagents into the apparatus as follo
