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1、BRITISH STANDARD BS 6043-1.13: 1994 Methods of sampling and test for Carbonaceous materials used in aluminium manufacture Part 1: Electrode pitch Section 1.13 Determination of sulfur content (routine method) Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:37:02 GMT+00:00 2006, Uncontrolled
2、 Copy, (c) BSI BS 6043-1.13:1994 This British Standard, having been prepared under the direction of the Chemicals Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 January 1994 BSI 10-1999 The following BSI references relate to the work
3、on this standard: Committee reference CIC/24 Draft for comment 93/504549 DC ISBN 0 580 22388 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Chemicals Standards Policy Committee (CIC/-) to Technical Committee CIC/24, upon which the fol
4、lowing bodies were represented: Aluminium Federation British Ceramic Research Ltd. Chemical Industries Association Institute of Petroleum Refractories Association of Great Britain Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:37:02
5、 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-1.13:1994 BSI 10-1999i Contents Page Committees responsibleInside front cover Forewordii 1Scope1 2References1 3Principle1 4Reagents1 5Apparatus1 6Preparation of apparatus3 7Sampling and test sample preparation3 8Procedure3 9Determination of the bla
6、nk4 10Calculation of result4 11Test report4 Figure 1 Absorption train and furnace2 Figure 2 Temperature distribution curve2 List of referencesInside back cover Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:37:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-1.13:1994 ii BSI 10-1999
7、Foreword This Section of BS 6043 has been prepared under the direction of the Chemicals Standards Policy Committee. BS 6043 provides methods of sampling and test for carbonaceous materials used in the production of aluminium. The standard is published in four Parts, each Part being divided into Sect
8、ions. Part 1 comprises a series of methods of test for electrode pitch as follows. Other international methods of test for electrode pitch are under consideration and, subject to approval by the United Kingdom, will be published as they become available. This Section is derived from 8.3 of BS 1016-6
9、:1989, which details a high temperature method for determination of total sulfur which interlaboratory tests have shown to be suitable as a routine test method. It does not replace BS 6043-1.9:1989 which is the reference method. This standard describes a method of test only, and should not be used o
10、r quoted as a specification defining limits of purity. Reference to this Section should state that the method of test used is in accordance with BS 6043-1.13:1993. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible fo
11、r their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. SectionSubjectIdentical with 1.1SamplingISO 6257 1.2Water content (Dean and Stark method)ISO 5939 1.3Softening point (ring and ball method)ISO 5940 1.4Content of toluene-insolub
12、le materialISO 6376 1.5Content of quinoline-insoluble materialISO 6791 1.6Coking valueISO 6998 1.7Density 1.8AshISO 8006 1.9Sulfur content (bomb method)ISO 9055 1.10Volatile matter content 1.11C/H ratio in the quinoline insoluble fraction 1.12Mesophase content 1.13Sulfur content (routine method) Sum
13、mary of pages This document 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 f
14、ront cover. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:37:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-1.13:1994 BSI 10-19991 1 Scope This British Standard describes a method for determining the sulfur content of pitch used in the production of aluminium. The method is applic
15、able to pitches of both coal tar and petroleum origin, provided that they contain between 0.1 % (m/m) and 4.0 % (m/m) sulfur. 2 References 2.1 Normative references This British Standard incorporates, by reference, provisions from specific editions of other publications. These normative references ar
16、e cited at the appropriate points in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this British Standard only when incorporated in it by updating or revision. 2.2 Informative references This British St
17、andard refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be made to the latest editions. 3 Principle A known mass of the sample is burned in a strea
18、m of oxygen at a temperature of 1 350 C. The oxides of sulfur formed, together with any chlorine present, are absorbed in neutral hydrogen peroxide and determined volumetrically. A correction is made to take account of the chlorine content of the sample. Aluminium oxide is added to the sample to pre
19、vent the retention of sulfur in the ash. 4 Reagents 4.1 General. All reagents, unless otherwise specified, shall be analytical reagent grade. Water conforming to grade 3 of BS 3978:1987 shall be used throughout. 4.2 Disodium tetraborate solution, c(“Na2B4O7.10H2O) = 0.025 mol/l. 4.3 Sulfuric acid so
20、lution, c(“H2SO4) = 0.025 mol/l. 4.4 Hydrogen peroxide solution, consisting of 3 parts of 100 volume H2O2 and 97 parts of water, neutralized with the disodium tetraborate solution (4.2) to the screened indicator (4.5). 4.5 Screened indicator, consisting of equal volumes of a) and b) prepared as foll
21、ows and mixed immediately before use: a) 0.125 g of methyl red dissolved in 100 ml of 95 % (V/V) ethanol solution; b) 0.083 g of methylene blue dissolved in 100 ml of 95 % (V/V) ethanol solution. Store in a dark glass bottle. 4.6 Mercury(II) oxycyanide solution, consisting of approximately 100 ml of
22、 water saturated with mercury(II) oxycyanide (3Hg(CN)2.HgO). Agitate thoroughly, filter and neutralize the filtrate with the sulfuric acid solution (4.3) to the screened indicator (4.5). Store the solution in a dark glass bottle. Do not keep longer than 4 days. WARNING. This compound and its solutio
23、n are toxic and should be handled with appropriate care. 4.7 Aluminium oxide, finely divided, particle size approximately 0.1 mm. 4.8 Oxygen 4.9 Sodium hydroxide on an inert base, preferably of coarse grading, for example 1.7 mm to 1.2 mm, and preferably of the self-indicating type. 5 Apparatus 5.1
24、Ordinary laboratory apparatus 5.2 Combustion furnace and absorption train, as shown in Figure 1, and consisting of the following. 5.2.1 Furnace, electrically heated, designed to carry a tube of 28.5 mm outside diameter and to heat it over a length of about 125 mm to give a temperature of 1 350 C at
25、the centre of the hot zone and a temperature distribution curve similar to that shown in Figure 2. 5.2.2 Combustion tube, of 22 mm internal diameter and 28.5 mm outside diameter and 0.65 m long, made of refractory aluminous porcelain that is not permeable to gases at 1 400 C. 5.2.3 Combustion boat,
26、of iron-free unglazed porcelain, 70 mm long, 12.5 mm wide and 10 mm deep, that does not blister, discolour or change in mass on heating at 1 350 C in oxygen for 3 h. 5.2.4 Silica pusher, comprising a sealed tube or rod of silica, 6 mm in diameter and approximately 450 mm long, flattened at one end t
27、o form a disc of 12 mm diameter for pushing the boat into the furnace. The pusher passes loosely through a glass or metal T-piece, one end of which fits into the rubber stopper that closes the inlet end of the combustion tube, the other being sealed with a rubber sleeve through which the pusher slid
28、es (see Figure 1). Oxygen is admitted through the limb of the T-piece. The pusher is marked in millimetres from the disc end for convenience in measuring how far the boat is pushed into the combustion tube. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:37:02 GMT+00:00 2006, Uncontrolled
29、Copy, (c) BSI BS 6043-1.13:1994 2 BSI 10-1999 5.2.5 Hook, comprising a length of stiff nickel chromium wire with a hooked end, to extract the boat from the furnace on to a piece of refractory tile. 5.2.6 Flowmeter, capable of measuring rates of flow of oxygen of up to 300 ml/min. 5.2.7 Pressure gaug
30、e, to measure the back pressure on the system, normally 0.5 kPa to 0.7 kPa. 5.2.8 Heat-resistant stopper, of acrylonitrile or chloroprene rubber, for attaching the absorption train to the combustion tube. 5.2.9 Silica adaptor, comprising a translucent silica tube, 10 mm outside diameter and approxim
31、ately 250 mm long, terminating at one end in a funnel of 20 mm outside diameter. Figure 1 Absorption train and furnace Figure 2 Temperature distribution curve Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:37:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-1.13:1994 BSI 10-19993 5.2
32、.10 Purification train, comprising a tower containing sodium hydroxide on an inert base (see 4.9) for removing any oxides of sulfur from the oxygen supply. 5.2.11 Absorption vessel, comprising a gas washing tube or bottle with a sintered disc of porosity grade P40 conforming to BS 1752:1983, of such
33、 a size that a 90 mm seal of liquid is obtained with 100 ml of liquid in the vessel. 5.2.12 Pressure regulator, comprising a bottle containing mercury, fitted with inlet and outlet tubes and a third tube capable of being moved up or down to regulate the suction on the system. 5.2.13 Vacuum pump, or
34、other suitable pump. 6 Preparation of apparatus Insert the combustion tube (5.2.2) into the furnace (5.2.1) so that it projects 100 mm at the exit end. Insert at this end the heat-resistant stopper (5.2.8) carrying the silica adaptor (5.2.9) and adjust the latter so that the open end of the funnel i
35、s approximately 150 mm into the combustion tube. Insert the rubber stopper carrying the silica pusher (5.2.4) at the inlet end of the combustion tube and connect the oxygen supply through the purification train (5.2.10) to the limb of the T-piece. 7 Sampling and test sample preparation 7.1 Sampling
36、Sample the pitch in accordance with BS 6043-1.1:1981. 7.2 Preparation of test sample Prepare the test sample immediately before the determination. In the case of hard pitches, grind the sample so that it passes through a sieve of nominal aperture size 212 4m using a sieve complying with the requirem
37、ents of BS 410:1986. If the pitch is too soft for grinding, melt and mix the sample in a covered vessel ensuring that its temperature does not exceed 150 C and that the melting period does not exceed 10 min. Take the material for the test portion from the molten sample. 8 Procedure Raise the tempera
38、ture of the furnace (5.2.1) to 1 350 C and pass the oxygen (4.8) through the combustion tube (5.2.2). Weigh about 0.5 g of the test sample (7.2) to the nearest 0.1 mg, spread uniformly in the combustion boat (5.2.3) and cover with 0.5 g of the aluminium oxide (4.7). Measure 100 ml of the hydrogen pe
39、roxide solution (4.4) to the nearest 1 ml into the absorption vessel (5.2.11) and assemble the apparatus. Adjust the rate of gas flow by means of the vacuum pump (5.2.13) and the depth of seal in the pressure regulator (5.2.12) to maintain a slight suction in the combustion tube with oxygen entering
40、 at 300 ml/min as shown on the flowmeter (5.2.6). Remove the rubber stopper carrying the silica pusher and insert the charged boat into the combustion tube to a position such that its centre is 240 mm from the centre of the hottest zone. With the silica pusher fully withdrawn, replace the rubber sto
41、pper and continue to pass oxygen at 300 ml/min. At the end of each of the next 12 one-minute periods, push the boat forward 20 mm, withdrawing the silica pusher each time, if necessary, to prevent its distortion. Allow the boat to remain in the hottest zone for a further 4 min. Alternatively, contin
42、uous mechanical pushing of the boat may be used provided that the heating schedule specified is maintained. Disconnect the absorption vessel and remove the silica adaptor. Withdraw the boat on to a refractory tile using the hook (5.2.5). NOTEIf the sample combusts too quickly for the gases to be abs
43、orbed by the washer bottle, the boat, should be pushed forward 10 mm at the end of each of 24 one-minute periods. Wash the silica adaptor with water, collecting the washings in a 250 ml flask. Transfer the contents of the absorption vessel to the flask, washing the vessel with water and collecting t
44、he washings in the same flask. NOTEThe total bulk of liquid should not exceed 150 ml. Add two or three drops of the screened indicator (4.5) and titrate with the disodium tetraborate solution (4.2), using a suitable burette, to the neutral steel-grey colour. Add 10 ml of the mercury(II) oxycyanide s
45、olution (4.6) (sufficient excess for pitches containing up to 0.5 % chlorine) and titrate with the sulfuric acid solution (4.3) using a suitable burette to the neutral steel-grey colour. NOTETitration against a white background is strongly recommended. Licensed Copy: sheffieldun sheffieldun, na, Wed
46、 Dec 06 14:37:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-1.13:1994 4 BSI 10-1999 9 Determination of the blank Carry out a blank determination under the same conditions as the actual determination but omitting the sample. 10 Calculation of result The sulfur content, S %, is given by the fo
47、llowing equation. Report the value of S as a percentage (m/m) to two significant figures. 11 Test report The test report shall include the following information: a) a complete identification of the test sample; b) a reference to this British Standard, ie. BS 6043-1.13:1993; c) the sulfur content of
48、the test sample, calculated and expressed in accordance with clause 10; d) any unusual features noted during the determination; e) any operation not included in this British Standard or regarded as optional. where mis the mass of sample taken (in g); V1is the volume of disodium tetraborate solution
49、(4.2) used in the determination (in ml); V2is the volume of disodium tetraborate solution (4.2) used in the blank determination (in ml); V3is the volume of sulfuric acid solution (4.3) used in the determination (in ml); V4is the volume of sulfuric acid solution (4.3) used in the blank determination (in ml). S 0.0401 m - - V1V2V3V4()= Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:37:02 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-1.13:1994 BSI 10-1999 List of references Normative references BSI standards publications
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