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1、BRITISH STANDARD BS 5634:1978 Methods of test for Potassium hydroxide UDC 661.832.23:546.32 36:543.062 Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:49:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5634:1978 This British Standard, having been prepared under the direction of the Chemic
2、als Standards Committee, was published under the authority of the Executive Board on 29 December 1978 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference CIC/22 Draft for comment 75/52128 DC ISBN 0 580 10378 1 Cooperating organizations The Chemicals Stan
3、dards Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Association of Fatty Acid Distillers British Tar Industry Association Chemical Industries Association* Departm
4、ent of Health and Social Security Department of Industry, Laboratory of the 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 Gre
5、at Britain Ltd. Royal Institute of Public Health and Hygiene Soap and Detergent Industry Association* Society for Analytical Chemistry Standardization of Tar Products Tests Committee The organizations marked with an asterisk in the above list, together with the following, were directly represented o
6、n the committee entrusted with the preparation of this British Standard: Asbestos Cement Manufacturers Association British Man-made Fibres Federation British Textile Employers Association Fabric Care Research Association Society of Glass Technology Amendments issued since publication Amd. No.Date of
7、 issueComments Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:49:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5634:1978 BSI 12-1999i Contents Page Cooperating organizationsInside front cover Forewordii Section 1. General 1Scope1 2References1 3Preparation of sample solution1 Section 2.
8、 Methods of test 4Determination of total hydroxide content1 5Determination of carbonate content2 6Determination of sodium content4 7Determination of chloride content5 8Determination of content of sulphur compounds7 9Determination of nitrate content9 10Determination of cyanide content11 11Determinati
9、on of silica content12 12Determination of calcium content14 13Determination of iron content17 14Determination of zinc content18 15Determination of copper content20 16Determination of lead content21 17Determination of nickel content23 18Determination of arsenic content24 Figure 1 Typical apparatus fo
10、r the determination of carbonate content3 Figure 2 Typical apparatus for the determination of content of sulphur compounds8 Figure 3 Typical apparatus for the preparation of the reducing solution (8.3.7) used in the determination of content of sulphur compounds9 Publications referred toInside back c
11、over Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:49:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5634:1978 ii BSI 12-1999 Foreword This British Standard, prepared under the direction of the Chemicals Standards Committee, comprises methods of test for potassium hydroxide in solid fo
12、rm and in aqueous solution. It provides a full range of tests for use in conjunction with BS 5633, 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
13、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 United Kingdom, b
14、y Sub-committee 5 of Technical Committee 47, Chemistry, of the International Organization for Standardization (ISO). The relationship between the appropriate British Standard methods and the International Standards is shown in the table below. The method of ISO 2466 has been modified by the introduc
15、tion of two sample solutions, one a solution of the sample corresponding to solution A in ISO 2466 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 solution B. If it is necessary to determine
16、all the trace metals, the use of solution B results in considerable saving of time. The procedure used for the determination of arsenic, which is the same as that described in BS 4404, is technically similar to the method given in ISO 2590. Atomic absorption methods are described for the determinati
17、ons of calcium, zinc and lead. The flame emission photometric method used for the determination of sodium is similar in principle to that described in ISO 1550 but, in accordance with United Kingdom comments not accepted by the ISO committee, does not restrict the fuel for the atomizer-burner of the
18、 flame spectrophotometer 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 United Kingdom. There are at present no ISO methods for
19、the determination of the contents of nitrate, cyanide, zinc, copper, lead and nickel in potassium hydroxide. BS 5634: Preparation/ Determination of Corresponding International Standard sample solutions total hydroxide content carbonate content chloride content content of sulphur compounds silica con
20、tent ISO 2466, “Potassium hydroxide for industrial use Sampling Test sample Preparation of the main solution for carrying out certain determinations” ISO 990, “Potassium hydroxide for industrial use Method of assay” ISO 2900, “Potassium hydroxide for industrial use Determination of carbon dioxide co
21、ntent Titrimetric method” ISO 3177, “Potassium hydroxide for industrial use Determination of chlorides content Photometric method” ISO 3194, “Potassium hydroxide for industrial use Determination of sulphur compounds Method by reduction and titrimetry” ISO 995, “Potassium hydroxide for industrial use
22、 Determination of silica content Reduced molybdosilicate photometric method” Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:49:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5634:1978 BSI 12-1999iii A British Standard does not purport to include all the necessary provisions of a contrac
23、t. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. BS 5634: Preparation/ Determination of Corresponding International Standard calcium content iron content ISO 3698, “Potassium hyd
24、roxide for industrial use Determination of calcium and magnesium contents Flame atomic absorption method” ISO 994, “Potassium hydroxide for industrial use Determination of iron content 1,10-Phenanthroline photometric method” Summary of pages This document comprises a front cover, an inside front cov
25、er, pages i to iv, pages 1 to 26, 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. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:49
26、:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:49:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5634:1978 BSI 12-19991 Section 1. General 1 Scope This British Standard specifies methods for sampling and testing potassium hydroxide
27、 in solid form and in aqueous solution. 2 References 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
28、is an acidified solution of the sample in water and 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
29、uniform sampling for the determination of metallic impurities. 3.2 Reagents. The reagents used shall be of recognized analytical quality. Water complying with the requirements of BS 3978 shall be used throughout. 3.2.1 Hydrochloric acid, approximately 5N solution. 3.2.2 Methyl orange indicator solut
30、ion, 0.4 g/l, prepared as described in BS 4123. 3.3 Apparatus. 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
31、 reaction with silica can occur. The maximum particle size of solid test portions shall not exceed about 6 mm. 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
32、 phosphorus (V) oxide and similar dishes of potassium hydroxide pellets to remove water vapour and carbon dioxide, respectively. These absorbents should be left in the glove box for at least 1 h before it is used. 3.4.2 Preparation of solution A. Weigh, accurately, 100 1 g of the solid sample or 200
33、 2 g of the liquid sample into an alkali-resistant container fitted with a lid. If the sample is solid, dissolve it in 250 ml of freshly boiled and cooled water in an alkali-resistant beaker and cool. Transfer the solution, or the original sample if liquid, to a 500 ml alkali-resistant graduated cyl
34、inder, dilute to the mark with water, mix and transfer immediately to an airtight, alkali-resistant plastics bottle. Label as “Solution A”. 3.4.3 Preparation of solution B. Weigh 10.0 0.1 g of the solid sample, or 20.0 0.2 g of the liquid sample, into a 250 ml beaker. Add 50 ml of water, swirl to di
35、ssolve or mix, and titrate with the hydrochloric acid solution (3.2.1) using the methyl orange solution (3.2.2) as indicator. Let the titration be X ml. Discard the solution. Weigh, accurately, 100 1 g of the solid sample or 200 2 g of the liquid sample into a 1 000 ml beaker. Add 200 ml of water an
36、d swirl to dissolve or mix. From a measuring cylinder cautiously add (10 X + 5) ml of the hydrochloric acid solution (3.2.1) with continuous stirring. Cool the contents of the beaker to ambient temperature, transfer to a 1 000 ml one-mark volumetric flask, dilute to the mark with water and mix. Labe
37、l as “Solution B”. 3.4.4 Preparation of solution C. Evaporate (10 X + 5) ml (see 3.4.3) of the hydrochloric acid solution (3.2.1) to 5 ml in a 1 000 ml beaker, taking care to avoid contamination. Transfer the residual solution quantitatively to a 1 000 ml one-mark volumetric flask, dilute to the mar
38、k with water and mix. Label as “Solution C”. Section 2. Methods of test 4 Determination of total hydroxide 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 hydroch
39、loric acid solution using methyl orange as indicator and a correction is made for the carbonate content, determined by the method of test specified in clause 5, to give total hydroxide content. 4.3 Reagents. The reagents used shall be of recognized analytical quality. Water complying with the requir
40、ements of BS 3978, freshly boiled to free it from carbon dioxide, shall be used throughout. 4.3.1 Hydrochloric acid, 1N standard volumetric solution. Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:49:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5634:1978 2 BSI 12-1999 4.3.2 Methyl ora
41、nge indicator solution, 0.4 g/l, prepared as described in BS 4123. 4.4 Apparatus. Ordinary laboratory apparatus and the following are required. 4.4.1 Burette, 50 ml capacity, complying with the requirements for class A of BS 846. 4.5 Procedure. Weigh, to the nearest 0.01 g, 25 g of the solid sample
42、or 50 g of the liquid sample. Dissolve in or mix with 200 ml of water in a 400 ml beaker. Cool and transfer to a 500 ml one-mark volumetric flask, dilute to the mark with water and mix. Pipette 50.0 ml of this solution into a 500 ml conical flask. Add 80 ml of water and five drops of the methyl oran
43、ge 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), is given by the following formula: 5 Determination of carbo
44、nate content 5.1 Field of application. The method is applicable to products having carbonate contents, expressed as potassium carbonate (K2CO3), greater than 0.02 % m/m. 5.2 Principle. Carbon dioxide is released by acidifying and heating the test solution. The released carbon dioxide is entrained in
45、 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 reagents used shall be of recognized analytical quality. Water comp
46、lying with the requirements of BS 3978 shall be used throughout. 5.3.1 Hydrochloric acid, approximately 5N solution. 5.3.2 Hydrochloric acid, 0.1N standard volumetric solution. 5.3.3 Barium hydroxide, approximately 0.1N solution. Weigh 15 0.1 g of barium hydroxide octahydrate, Ba(OH)2.8H2O, dissolve
47、 in water, dilute to 1 000 ml and mix. Allow precipitated barium carbonate to settle out before use. 5.3.4 Methyl orange indicator solution, 0.4 g/l, prepared as described in BS 4123. 5.3.5 Thymolphthalein indicator solution, 2 g/l, prepared as described in BS 4123. 5.3.6 Nitrogen or air, free from
48、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 portion. Measure out a volume of the solution A (3.4.2)
49、 containing not more than 25 g of potassium hydroxide or 150 mg of potassium carbonate. 5.5.2 Blank test. Subsequent to the determination, carry out a blank test following the procedure specified in 5.5.3 but omitting the test portion. where Vis the volume of the hydrochloric acid solution (4.3.1) used in the determination of total alkali (in ml) mis the mass of the test portion (in g) Ais the carbonate content of the sample, expressed as the percentage by mass of potassium carbonate (K2CO3) (see clause 5) Aflask, 500 ml cap