BS-6043-4.2-1991.pdf

BRITISH STANDARD BS 6043-4.2: 1991 Methods of sampling and test for Carbonaceous materials used in aluminium manufacture Part 4: Cold ramming pastes Section 4.2 Determination of effective binder content and aggregate content by extraction with quinoline; determination of aggregate size distribution NOTEIt is recommended that this Section be read in conjunction with the general information in BS 6043-4.0, published separately. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:36:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-4.2:1991 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 31 October 1991 © BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference CIC/24 Draft for comment 90/54842 DC ISBN 0 580 19932 0 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 following 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 14:36:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-4.2:1991 © BSI 09-1999i Contents Page Committees responsibleInside front cover Forewordii 0Introduction1 1Scope1 2Principle1 3Definition1 4Reagents1 5Apparatus1 6Sampling2 7Preparation of test sample2 8Procedure2 9Calculation and expression of results3 10Test report3 Publication(s) referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:36:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-4.2:1991 ii © BSI 09-1999 Foreword This Section of BS 6043 has been prepared under the direction of the Chemicals Standards Policy Committee to provide a method of test for cold ramming pastes used in the production of aluminium. There is no corresponding International Standard; however, it is intended, upon publication of this Section of BS 6043, that it be offered to the International Organization for Standardization (ISO) for possible adoption as an International Standard. It is essential that BS 6043-4.1 be read in conjunction with this Section of BS 6043. This standard describes a method of test only, and should not be used or quoted as a specification defining the characteristics of a product. Reference to this Section should indicate that the method of test used is in accordance with BS 6043-4.2:1991. 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 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 front cover. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:36:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-4.2:1991 © BSI 09-19991 0 Introduction In order to determine the particle-size distribution of the aggregate used in cold ramming pastes it is necessary to obtain the aggregate in a binder-free state. The most practicable way to achieve this is by extraction of the binder by a suitable solvent, and the most effective common solvent for coal-tar and bituminous binders is quinoline. Most coal tars are not totally soluble in quinoline, but have a small content of insoluble matter which principally comprises infusible solid carbonaceous particles smaller than approximately 50 Èm. This insoluble matter is effectively part of the solid aggregate of the cold ramming paste and is measured as such by this method. The effective binder is defined as that proportion of the product which is soluble in quinoline. Although quinoline is the most effective common solvent for the present purpose, it has the disadvantage of being expensive and of having a high boiling point which makes the removal of its last traces from the extracted residue difficult by normal drying processes. However, when the most complete separation of the binder from the aggregate is required, e.g. for referee purposes, quinoline is the solvent of choice, and the method given in this Section should be employed. For more rapid routine analysis, e.g. during the production of cold ramming pastes with coal-tar or bituminous binders, a more tractable solvent is required. BS 6043-4.3 describes a simplified procedure which uses dichloromethane as the solvent, but has the limitation that the method is suitable only for determining the content and size-distribution of the aggregate of particle sizes above 53 Èm, because the solvent achieves a less complete extraction of the binder and the aggregate suffers contamination of the smaller particles with insoluble matter precipitated from the binder. NOTEThe procedure described in this Section of BS 6043 utilises dichloromethane, but only to remove residual traces of quinoline solvent from filters prior to oven drying. Neither this method, nor that of BS 6043-4.3 is suitable for use with cold ramming pastes made with resin-based binders such as phenol-formaldehyde or furan types. 1 Scope This Section of BS 6043 describes a method for determining the content and particle-size distribution of the solid aggregate component, and also for determining the effective binder content, of cold ramming pastes used in aluminium manufacture. The method is applicable to cold ramming pastes made with coal-tar or bituminous binders but not applicable for resin-based binders. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Principle A test portion of the cold ramming paste is digested under reflux with quinoline to dissolve the binder. The digestion mixture is poured on to a fine-aperture sieve, upon which the majority of the aggregate thus retained is washed free of residual binder with further portions of quinoline and then dried and weighed. The mixture and washings passing through the sieve are filtered through a filter pad and the very fine particles of aggregate thus recovered are likewise washed, dried and weighed. The content of aggregate is determined from the total mass of the particles retained on the sieve and the filter pad, and the content of quinoline-soluble matter is calculated by difference. The particle-size distribution of the solids retained on the fine-aperture sieve is determined by test sieving. 3 Definition For the purposes of this Section of BS 6043, the definitions given in BS 6043-4.1 apply, together with the following. 3.1 effective binder content that proportion of the product soluble in quinoline, expressed as a percentage by mass 4 Reagents WARNING. Refer to the reagent suppliers health and safety data sheets for the precautions which are to be observed for the safe use of quinoline and dichloromethane. 4.1 Quinoline, of purity at least 98 % (m/m), freshly distilled, boiling between 235 °C and 237 °C at 1013 mbar.1) 4.2 Dichloromethane, (methylene dichloride), of purity at least 98 % (m/m). 5 Apparatus 5.1 Ordinary laboratory apparatus. 5.2 Distillation flask, round-bottomed, of borosilicate glass, capacity 2 L, having a ground-glass socket. 1) 1 mbar = 100 Pa. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:36:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-4.2:1991 2 © BSI 09-1999 5.3 Reflux air condenser, of effective length 550 mm, having a ground-glass cone by means of which it may be fitted to the socket of the distillation flask (5.2). 5.4 Electric heating mantle, capable of maintaining gentle boiling of the contents of the distillation flask (5.2) whilst under reflux. 5.5 Nest of test sieves, 200 mm in diameter, complying with BS 410, of stainless-steel wire cloth, with nominal apertures of between 53 Èm and 5 mm, inclusive, with lid and receiver. NOTEOther nominal apertures recommended for inclusion are: 2 mm and 1 mm, 500 Èm, 250 Èm, 150 Èm and 75 Èm. 5.6 Receiver test sieve, 200 mm in diameter, complying with BS 410, of stainless-steel wire cloth, of 53 Èm nominal aperture. Prepare by heating in the electric oven (5.8) for 1 h at a temperature of 110 ± 5 °C then allow to cool to ambient temperature in a desiccator and store in the desiccator until required for use. 5.7 Dish, of glass or porcelain, capable of fitting below the receiver test sieve (5.6) and collecting all the liquids which pass through. 5.8 Electric oven, of size sufficient to contain the receiver test sieve (5.6) and capable of being controlled at 110 ± 5 °C. 5.9 Funnel, Hartley 3-piece, or equivalent, having a disc diameter of 120 mm. 5.10 Glass-fibre filter pads, of diameter 120 mm, with a retention of at least 98 % (m/m) for particles of size 1.2 Èm. Dry by heating for 1 h at 110 ± 5 °C then store in a desiccator until required for use. 5.11 Mechanical sieve shaker, capable of accommodating the nest of test sieves (5.5) with the lid and receiver, as described in BS 1796-1. 6 Sampling Prepare a representative laboratory sample of cold ramming paste in accordance with BS 6043-4.1. 7 Preparation of test sample Take 100 ± 0.05 g from the laboratory sample (see clause 6) of cold ramming paste in accordance with 5.5.3 of BS 6043-4.1:1991. 8 Procedure 8.1 Transfer the test sample (see clause 7) quantitatively to the distillation flask (5.2). Add 1 L of the quinoline (4.1) and swirl the contents of the flask to mix the test sample with the quinoline. Place the flask in the electric heating mantle (5.4) and fit the reflux air condenser (5.3) to the flask. Bring the contents of the flask to a steady boil and continue boiling under reflux for 1 h. Switch off the electric heating mantle and allow the flask and its contents to cool to 50 ± 5 °C. Weigh the receiver test sieve (5.6) to the nearest 0.01 g then place it over the dish (5.7). Carefully transfer the hot contents of the flask as completely as possible to the sieve. Rinse the flask using successive 20 mL portions of the quinoline at 50 ± 5 °C until all the visible solids have been transferred to the sieve. Wash the contents of the sieve with the quinoline at 50 ± 5 °C until the washings passing through the sieve show no additional colour due to dissolved binder. Allow the quinoline to drain from the sieve contents then separate the test sieve and the dish. 8.2 Transfer the contents of the dish quantitatively to a container to await recovery of the solids by filtration. 8.3 Replace the receiver test sieve over the dish and wash the aggregate on the sieve with 10 successive 100 mL portions of the dichloromethane (4.2), allowing each portion of the solvent to drain before adding the next. After the final wash, leave the sieve and its contents to drain for 1 h and discard the washings. Place the receiver test sieve with its contents in the oven (5.8) maintained at 110 ± 5 °C for 1 h, taking care that no boiling of residual dichloromethane occurs, leading to loss of solids. Remove the receiver test sieve with its contents and allow to cool to ambient temperature in a desiccator. Weigh the receiver test sieve and its contents to the nearest 0.01 g. Repeat the operations of heating, cooling and weighing until the difference between two consecutive weighings does not exceed 0.01 g. 8.4 Weigh a dried filter pad (5.10) to the nearest 0.01 g. Assemble the funnel (5.9) with the filter pad and fit the assembly into the neck of a filter flask. Moisten the filter pad with a little of the quinoline at 50 ± 5 °C and apply suction. When the quinoline has passed through the filter, start filtering the retained digestion liquid and its associated quinoline washings (see 8.2). Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:36:04 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6043-4.2:1991 © BSI 09-19993 When the filtration is complete, rinse the container with successive 20 mL portions of the quinoline at 50 ± 5 °C to transfer any residual solids to the filter. When all the visible solids have been transferred, continue to wash the solids on the filter with successive 20 mL portions of the quinoline at 50 ± 5 °C until the filtrate does not show any additional colour due to dissolved binder. Allow the last portion of quinoline to drain, then wash the residue with 10 successive 20 mL portions of the dichloromethane, allowing each washing to drain before adding the next. Release the suction, remove the filter pad with the residue and transfer any solid which remains on the walls of the funnel to the pad. Place the pad in the oven (5.8) maintained at 110 ± 5 °C for 1 h. Remove the pad from the oven and allow it to cool to ambient temperature in a desiccator. Weigh the pad bearing the residue to the nearest 0.01 g. Repeat the operations of heating, cooling and weighing until the difference between two consecutive weighings does not exceed 0.01 g. 8.5 Recover the dried aggregate from the receiver test sieve (see 8.3) by inverting the sieve over a suitably-sized piece of clean smooth-surface paper. Remove any particles trapped in the mesh by tapping and gently brushing the underside of the sieve cloth. 8.6 Sieve the recovered aggregate using the nest of test sieves (5.5) and the mechanical sieve shaker (5.11) in accordance with BS 1796-1 for dry sieving. 9 Calculation and expression of results 9.1 Effective binder content Calculate the effective binder content B of the test sample, expressed as a percentage by mass, from the following equation: 9.2 Aggregate content Calculate the aggregate content A of the test sample, as a percentage by mass, from the following equation, using the variables defined in 9.1: 9.3 Aggregate particle-size distribution Calculate the percentage values, by mass, of material retained on each sieve (see 8.6), on the basis of the total mass of aggregate recovered in 8.3 and 8.4. Express the result to one decimal place. Tabulate the results as the percentage values, by mass, retained on the individual sieves in descending order of nominal aperture. 10 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, i.e. BS 6043-4.2:1991; c) the results for the percentage content of effective binder and aggregate expressed in accordance with 9.1 and 9.2 respectively, and calculated to one decimal place; d) the results for the particle-size distribution, expressed in accordance with 9.3; e) any unusual features noted during the determination; f) any operation not inclu