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1、BRITISH STANDARD BS 6092-3: 1981 ISO 1690:1976 Methods of Sampling and test for sodium and potassium silicates for industrial use Part 3: Determination of silica content (gravimetric method) ISO title: Sodium and potassium silicates for industrial use Determination of silica content Gravimetric meth
2、od by insolubilization NOTEIt is recommended that this Part be read in conjunction with the information in the “General introduction” published separately as BS 6092-0. UDC 661.683/.684:546.32284 + 546.33284:543.21.062:546.284 31 Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:09:39 GMT+00
3、:00 2006, Uncontrolled Copy, (c) BSI BS 6092-3:1981 This British Standard, having been prepared under the direction of the Chemicals Standards Committee, was published under the authority of the Executive Board and comes into effect on 27 February 1981 BSI 12-1999 The following BSI references relate
4、d to the work on this standard: Committee references CIC/22 Draft for comment 73/55424 DC ISBN 0 580 12037 6 Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:09:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6092-3:1981 BSI
5、 12-1999i Contents Page National forewordii 1Scope and field of application1 2Reference1 3Principle1 4Reagents1 5Apparatus1 6Procedure1 7Expression of results2 8Accuracy of the method2 9Test report2 Annex ISO Publications relating to sodium and potassium silicates for industrial use3 Publications re
6、ferred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:09:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6092-3:1981 ii BSI 12-1999 National foreword This Part of BS 6092 is identical with ISO 1690 “Sodium and potassium silicates for industrial use Determination of si
7、lica content Gravimetric method by insolubilization”, published in 1976 by the International Organization for Standardization (ISO). Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some termino
8、logy 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. Wherever
9、 the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Cross-references There is no British Standard corresponding directly to ISO 1686 to which reference is made in 6.1. Technically equivalent information on sampling is given in BS 6092-0.
10、 The standards listed in the Annex are intended for information only. Corresponding British Standards are listed in BS 6092-0. Additional information Water. Water complying with the requirements of clause 4 is specified in BS 3978 “Water for laboratory use”. Hydrochloric acid, of approximately 1.18
11、g/ml, about 36 % (m/m) solution, which is the corresponding reagent normally obtainable in the United Kingdom, is suitable for use in place of the approximately 1.19 g/ml solution specified in 4.1. WARNING. Aqueous hydrofluoric acid specified in 4.3 is a highly corrosive liquid which attacks glass;
12、the vapour is irritant and toxic. Its action on the skin and eyes is strongly corrosive, producing severe and painful burns which may not be immediately evident and which respond slowly to treatment. Samples should be handled only inside a well-ventilated fume cupboard. Rubber gloves, boots and gown
13、 of a suitable size to give adequate protection to the individual, and full head and face protection must be worn when handling the material. In the event of contact or suspected contact, flood with water and seek immediate medical attention. The manufacturers literature should be consulted for furt
14、her information. 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 do
15、cument comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, 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
16、Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:09:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6092-3:1981 BSI 12-19991 1 Scope and field of application This International Standard specifies a gravimetric method by insolubilization for the determination of the silica content of sodium and pota
17、ssium silicates for industrial use. 2 Reference ISO 1686, Sodium and potassium silicates for industrial use Samples and methods of test General. 3 Principle Insolubilization of silica by evaporation to dryness of a test portion previously acidified with hydrochloric acid. Dissolution of the soluble
18、salts, filtration and washing of the insoluble matter. Second insolubilization by evaporation of the filtrate and washings under the same conditions. Further dissolution of the soluble salts, filtration and washing of the second insoluble matter. Calcination and weighing of the two lots of insoluble
19、 matter simultaneously. Volatilization of silica by heating after addition of hydrofluoric and sulphuric acids and weighing of the residue after calcination. The difference in mass represents the silica present in the test portion. 4 Reagents During the analysis, use only reagents of recognized anal
20、ytical grade and only distilled water or water of equivalent purity. 4.1 Hydrochloric acid, approximately 1,19 g/ml, about 38 % (m/m) solution or approximately 12 N. 4.2 Sulphuric acid, approximately 1,84 g/ml, about 96 % (m/m) solution or approximately 36 N. 4.3 Hydrofluoric acid, approximately 1,1
21、5 g/ml, about 40 % (m/m) solution. 4.4 Silver nitrate, 10 g/l nitric solution. Dissolve 1 g of silver nitrate in water, add 10 ml of nitric acid solution, approximately 1,40 g/ml, and make up the volume to 100 ml. 5 Apparatus Ordinary laboratory apparatus and 5.1 Platinum crucible of height approxim
22、ately 40 mm and top diameter 30 mm, with lid. 5.2 Electric oven, capable of being controlled at 100 to 105 C and at 110 to 120 C. 5.3 Electric furnace, capable of being controlled at 950 to 975 C. 6 Procedure 6.1 Test portion and preparation of test solution Weigh, to the nearest 0,01 g, 10 1 g of t
23、he test sample (see ISO 1686) and place it in a 250 ml one-mark volumetric flask. Dissolve with water, dilute to the mark and mix. 6.2 Determination Take 25,0 ml (corresponding to approximately 1 g of test sample) of the test solution (6.1) and place in a porcelain dish of suitable capacity. Careful
24、ly add, while stirring, 5 ml of the hydrochloric acid solution (4.1). Cover the dish with a watch-glass supported by a glass triangle and place it on a boiling water bath and evaporate to dryness. Heat the residue in the oven (5.2) controlled at 110 to 120 C for at least 1 h. After cooling, add 5 ml
25、 of the hydrochloric acid solution (4.1) and 10 ml of water. Place on the boiling water bath for 5 to 10 min and stir to dissolve the soluble salts. Filter through an ashless filter paper of medium porosity, and collect the filtrate quantitatively. Transfer the insoluble product quantitatively onto
26、the filter by means of hot water. Wash with hot water, adding the rinsing water to the filtrate. Continue washing until 10 ml of the filtrate from the funnel remain clear 5 min after the addition of 10 ml of the nitric solution of silver nitrate (4.4). (Discard this portion of the filtrate.) Transfe
27、r the filtrate and the rinsing water quantitatively into the dish already used and evaporate to dryness on a boiling water bath. Heat the residue in the oven (4.2) at 110 to 120 C for at least 1 h. After cooling, add 5 ml of the hydrochloric acid solution (4.1) and 10 ml of water. Licensed Copy: she
28、ffieldun sheffieldun, na, Wed Dec 06 14:09:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6092-3:1981 2 BSI 12-1999 Place on the boiling water bath for 5 to 10 min and stir in order to dissolve the soluble salts. Filter and wash the insoluble matter on another filter paper by following the procedu
29、re given above for the first filtration. Fold the filter papers containing the insoluble matter and place them in the platinum crucible (5.1). Dry in the oven controlled at 100 to 105 C, then ignite the paper with a low flame until the combustion stops. Allow to cool, and wet the residue with a few
30、drops of the sulphuric acid solution (4.2). Place the crucible and its contents on a hot-plate and evaporate the sulphuric acid. When the emission of white fumes has ceased, place the crucible in the furnace (5.3), controlled at 950 to 975 C, for 15 min in order to calcine its contents. Allow to coo
31、l in a desiccator to ambient temperature and weigh to the nearest 0,000 2 g. Wet the residue with a few drops of the sulphuric acid solution (4.2) and add, with care, 2 to 3 ml of the hydrofluoric acid solution (4.3). Heat gently on a hot-plate in order to volatilize the hydrofluoric acid and heat m
32、ore strongly in order to evaporate the sulphuric acid. If any residue remains in the crucible, repeat the treatment with the sulphuric and hydrofluoric acids. Finally, calcine in the furnace controlled at 950 to 975 C for 15 min, allow to cool in a desiccator to ambient temperature and weigh to the
33、nearest 0,000 2 g. 7 Expression of results The silica content, expressed as a percentage by mass of SiO2, is given by the formula where m0is the mass, in grams, of test portion contained in the volume of the solution used; m1is the mass, in grams, of the crucible containing the insoluble product bef
34、ore the treatment with hydrofluoric acid; m2is the mass, in grams, of the crucible after the treatment with hydrofluoric acid. 8 Accuracy of the method The results obtained using this method are reproducible to the nearest 0,2 % (m/m), in absolute value. 9 Test report The test report shall include t
35、he 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 operations not included in this International Standard or the International Standard to which reference is made, or regarded
36、 as optional. m1m2() 100 m0 - - Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:09:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6092-3:1981 BSI 12-19993 Annex ISO Publications relating to sodium and potassium silicates for industrial use ISO 1686, Samples and methods of test General. I
37、SO 1687, Determination of density at 20 C of samples in solution Method using density hydrometer and method using pyknometer. ISO 1688, Determination of dry matter Gravimetric method. ISO 1689, Calculation of the ratioor. ISO 1690, Determination of silica content Gravimetric method by insolubilizati
38、on. ISO 1691, Determination of carbonate content Gas-volumetric method. ISO 1692, Determination of total alkalinity Titrimetric method. ISO 2122, Preparation of solution of products not easily soluble in boiling water and determination of matter insoluble in water. ISO 2123, Determination of dynamic
39、 viscosity. ISO 2124, Determination of silica content Titrimetric method. ISO 3200, Determination of sulphate content Barium sulphate gravimetric method. ISO 3201, Determination of iron content 1,10-Phenanthroline photometric method. SiO2 Na2O - - SiO2 K2O - - Licensed Copy: sheffieldun sheffieldun,
40、 na, Wed Dec 06 14:09:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 blank Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:09:39 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6092-3:1981 BSI 12-1999 Publications referred to See national foreword. Licensed Copy: sheffieldun sheffieldun, na
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