BS-5688-12-1979 ISO-2761-1975.pdf
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1、BRITISH STANDARD BS 5688-12: 1979 ISO 2761:1975 Methods of test for Boric acid, boric oxide, disodium tetraborates, sodium perborates and crude sodium borates for industrial use Part 12: Determination of total titanium content of crude sodium borates ISO title: Crude sodium borates for industrial us
2、e Determination of total titanium content Photometric method NOTEIt is recommended that this Part be read in conjunction with the information in the “General introduction”, published separately as BS 5688-0. UDC 661.65:546.33273:543.062:546.821 Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04
3、15:51:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5688-12:1979 This British Standard, having been prepared under the direction of the Chemicals Standards Committee, was published under the authority of the Executive Board on 28 February 1979 BSI 12-1999 The following BSI references relate to th
4、e work on this standard: Committee reference CIC/16 Draft for comment 74/53496 DC ISBN 0 580 10545 8 National foreword This Part of BS 5688 is identical with ISO 2761 “Crude sodium borates for industrial use Determination of total titanium content Photometric method” published by the International O
5、rganization for Standardization (ISO). Terminology and conventions. The text of the International Standard has been approved as suitable for publication, without deviation, as a British Standard. Some terminology and certain conventions are not identical with those used in British Standards; attenti
6、on is 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 the words “International Standard” appear, referring to this standard, they should be interpreted as “Bri
7、tish Standard”. Additional information Water. Water complying with the requirements of clause 3 is specified in BS 3978 “Water for laboratory use”. WARNING NOTE. Potassium titanium oxalate, the use of which is specified in 3.4, is toxic. Inhalation of the dust and contact with the eyes and skin shou
8、ld be avoided. 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 docu
9、ment comprises a front cover, an inside front cover, pages i and ii, pages 1 and 2 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. Amendments issued since publicat
10、ion Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:51:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5688-12:1979 BSI 12-1999i Contents Page National forewordInside front cover 1Scope and field of application1 2Principle1 3Reagents1 4Apparatus1 5Procedure1
11、6Expression of results2 7Test report2 8Bibliographical reference2 Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:51:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:51:38 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5688-12:
12、1979 BSI 12-19991 1 Scope and field of application This International Standard specifies a photometric method for the determination of the total titanium content of crude sodium borates for industrial use, for material containing up to 0,1 % titanium. The method, as specified, is not applicable in t
13、he presence of vanadium or high silica content. Molybdenum and chromium also interfere. (See clause 8, “Bibliographical reference”). The same reference also states that fluoride destroys the colour and that phosphates and alkali sulphates have a slight fading action. 2 Principle Fusion of a test por
14、tion with sodium carbonate, extraction of the cooled melt with sulphuric acid and the addition of hydrogen peroxide. Photometric measurement, at a wavelength of approximately 420 nm, of the yellow-coloured complex ions formed. 3 Reagents During the analysis, use only reagents of recognized analytica
15、l reagent grade and only distilled water or water of equivalent purity. 3.1 Sodium carbonate, anhydrous. 3.2 Sulphuric acid, approximately 9 M solution. 3.3 Hydrogen peroxide, approximately 30 % (m/m) solution. 3.4 Titanium, standard solution, corresponding to 0,100 g of TiO2 per litre. Weigh, to th
16、e nearest 0,001 g, 0,443 g of potassium titanium oxalate dihydrate K2TiO(C2O4)2.2H2O and transfer it to a Kjeldahl flask. Add 1 g of ammonium sulphate and 100 ml of sulphuric acid, approximately 18 M solution. Heat the mixture gradually to boiling and keep it boiling gently for 10 min. Cool the solu
17、tion and pour it slowly and quantitatively, with stirring and cooling, into 750 ml of cold water. Transfer the solution quantitatively to a 1 000 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this standard solution contains 0,000 10 g of TiO2. 3.5 Titanium, standard solution, cor
18、responding to 0,020 g of TiO2 per litre. Take 100,0 ml of the standard titanium solution (3.4), transfer it to a 500 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this standard solution contains 0,000 020 g of TiO2. 3.6 Universal indicator paper 4 Apparatus Ordinary laboratory ap
19、paratus and 4.1 Platinum crucible, with platinum lid. 4.2 Spectrophotometer, or 4.3 Photoelectric absorptiometer 5 Procedure 5.1 Test portion Weigh, to the nearest 0,001 g, approximately 1 g of the test sample into the platinum crucible (4.1). 5.2 Blank test Carry out a blank test, at the same time
20、as the determination, following the same procedure and using the same quantities of all the reagents used for the determination. 5.3 Preparation of the calibration curve 5.3.1 Preparation of standard colorimetric solutions relating to photometric measurements carried out with cells of 4 cm optical p
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