BS-5688-6-1979 ISO-2214-1972.pdf
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1、BRITISH STANDARD BS 5688-6: 1979 ISO 2214:1972 Methods of test for Boric acid, boric oxide, disodium tetraborates, sodium perborates and crude sodium borates for industrial use Part 6: Determination of manganese content of boric acid, boric oxide and disodium tetraborates ISO title: Boric acid, bori
2、c oxide and Disodium tetraborates for industrial use Determination of manganese content Formaldehyde oxime 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 661.65:546.273:543.062:
3、546.711 Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:50:06 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5688-6:1979 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 Febru
4、ary 1979 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference CIC/16 Draft for comment 74/53496 DC ISBN 0 580 10539 3 National foreword This Part of BS 5688 is identical with ISO 2214 “Boric acid, boric oxide and disodium tetraborates for industrial use D
5、etermination of manganese content Formaldehyde oxime photometric method” published by the International Organization 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.
6、 Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn to the following. Where the words “International Standard” appear, referring to this standard, they should be interpreted as “British Standard”. Additional information Water. Water co
7、mplying with the requirements of clause 3 is specified in BS 3978 “Water for laboratory use”. Reagents. Unless otherwise stated, the reagents used in the determination shall be of recognized analytical grade. Hydrochloric acid, approximately 1.18 g/ml, about 36 % (m/m) solution, which is the corresp
8、onding reagent normally obtainable in the United Kingdom, is suitable for use in place of the solution specified in 3.4. WARNING NOTES. Hydroxylammonium chloride, the use of which is specified in 5.3.2, is toxic. Clause 5.4.1 requires the use of chloroform as an extractant. In view of its toxic natu
9、re, breathing of the vapour and contact with the eyes should be avoided. The evaporation of the chloroform extract in paragraph 5 should therefore be carried out in a fume cupboard. NOTEIn 3.4 and 3.5, the symbol for concentration by mass should be sloping, i.e. “(m/m)”. A British Standard does not
10、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 document comprises a front cover, an inside fro
11、nt cover, pages i and ii, pages 1 to 3 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 publication Amd. No.Date of issueComments Licensed C
12、opy: sheffieldun sheffieldun, na, Mon Dec 04 15:50:06 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5688-6:1979 BSI 12-1999i Contents Page National forewordInside front cover 1Scope and field of application1 2Principle1 3Reagents1 4Apparatus1 5Procedure1 6Expression of results2 7Test report3 License
13、d Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:50:06 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Mon Dec 04 15:50:06 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5688-6:1979 BSI 12-19991 1 Scope and field of application This International Stan
14、dard specifies a formaldehyde oxime method for the photometric determination of the manganese content of boric acid, boric oxide and disodium tetraborates for industrial use. 2 Principle Removal of the boron by evaporation with methanol and separation of manganese and other metals from the residue,
15、by extraction with chloroform, as their diethyldithiocarbamates. Wet destruction of the diethyldithiocarbamates with a sulphuric acid/hydrogen peroxide mixture. Removal of any interfering iron by extraction as the thiocyanate. Formation of the coloured manganese formaldehyde oxime complex in alkalin
16、e solution and photometric measurement at a wavelength of approximately 450 nm. 3 Reagents Distilled water or water of equivalent purity shall be used in the test. 3.1 Organic extraction solvent Mix equal volumes of amyl alcohol (mixed isomers) and amyl acetate. 3.2 Chloroform, redistilled. 3.3 Meth
17、anol, redistilled. 3.4 Hydrochloric acid, 1.19 g/ml approximately, 38 % (m/m) solution or approximately 12 N. 3.5 Ammonia solution, 0.88 g/ml approximately, 35 % (m/m) solution or approximately 18 N. 3.6 Sulphuric acid, approximately 16 N solution. 3.7 Sodium hydroxide, approximately 6 N solution. 3
18、.8 Ammonium thiocyanate, 100 g/l solution. 3.9 Formaldehyde oxime hydrochloride, 60 g/l solution. 3.10 Hydrogen peroxide, 500 g/l solution. 3.11 Hydroxylammonium chloride, 100 g/l solution. NOTESolid hydroxylammonium chloride should not be allowed to come into contact with the skin. The solution sha
19、ll be dispensed from a burette or safety pipette. 3.12 Potassium sodium tartrate, 100 g/l solution. 3.13 Sodium diethyldithiocarbamate, 10 g/l solution. Dissolve 1 g of sodium diethyldithiocarbamate in 100 ml of water and filter before use. 3.14 Manganese standard solution, containing 0.10 g/l of Mn
20、. Measure by means of a burette 45.51 ml of exactly 0.1 N potassium permanganate solution into a 250 ml conical flask. NOTEIf the normality of the potassium permanganate solution used is not exactly 0.1 N, use a volume of solution calculated to be equivalent to 45.51 ml of 0.1 N solution. Add to the
21、 flask, drop by drop, a saturated solution of sulphur dioxide until the contents are clear and colourless. Boil the solution to remove excess sulphur dioxide and then cool. Transfer quantitatively to a 500 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this solution contains 100 4
22、g of manganese. 3.15 Manganese standard solution, containing 0.01 g/l of Mn. Transfer 10.0 ml of the manganese standard solution (3.14) to a 100 ml one-mark volumetric flask, dilute to the mark and mix. 1 ml of this solution contains 10 4g of manganese. Prepare this solution just before use. 3.16 Cr
23、esol red, 0.2 g/l solution. 4 Apparatus Ordinary laboratory apparatus and 4.1 Spectrophotometer, with 4 cm cells, or 4.2 Photoelectric absorptiometer, with 4 cm cells. NOTEIt is essential that the glassware used in this determination be scrupulously clean; beakers etc. shall be cleaned with boiling
24、approximately 6 N hydrochloric acid solution and rinsed with water. 5 Procedure 5.1 Test portion Weigh, to the nearest 0.1 g, a quantity of the test sample, up to 10.0 g, containing not more than 25 4g of manganese. 5.2 Blank test Transfer 30 ml of the hydrochloric acid solution (3.4) to a beaker, h
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