1、INTERNATIONAL STANDARD IS0 10753 First edition 1994-02-01 Coal preparation plant - Assessment of the liability to breakdown in water of materials associated with coal seams Ateliers de prkparation du charbon - Evaluation de la fiabilit4 de la fragmentation dans Ieau de mat an outlet (HI allows the s
2、ample to be run off. The Andreasen sedimentation apparatus is modified by reducing the length of stem of the pipette, so that the sample is withdrawn at the 100 mm mark. The apparatus shall be protected from all sources of vi- bration during the test. 5.10 Suction device, capable of applying a stead
3、y, controlled suction to the sedimentation pipette (5.9). NOTE 3 An aspirator is preferred for this purpose. 5.11 Evaporating dish, of nickel or stainless steel, having a diameter of 50 mm. 5.12 Flask, of capacity at least 2 litres. 5.13 Thermostatically-controlled bath, capable of being maintained
4、at approximately ambient tempera- ture, to within f 0,2 “C, and of suitable dimensions to contain the sedimentation apparatus (5.91, a measuring cylinder (5.8) and the flask (5.12). The bath shall operate without causing significant vi- bration or disturbance of the measuring cylinder and its conten
5、ts, when placed in the bath. NOTE 4 If a thermostatically controlled bath is not avail- able, a large container filled with water that has been al- lowed to attain room temperature may be used instead. 2 Q IS0 IS0 10753:1994(E) E F 200 mm A 1 B 100 mm KW A Graduated cylindrical flask B Pipette C 10
6、ml Reservoir D Three-way stopcock E Groundglass stopper F Small opening in stopper (to allow air to enter) G Suction application point H Outlet Figure 2 - Modified Andreasen sedimentation apparatus 5.14 Drying oven, well ventilated and capable of being maintained in the temperature range 105 “C to 1
7、10 “C. 5.15 Stop clock. 5.16 Analytical balance(s), capable of weighing up to 20 g to the nearest 0,000 1 g and up to 200 Q to the nearest 0,Ol g. 5.17 Wash bottle, of capacity at least 400 ml, fitted with a fine spray-jet outlet. 5.18 Desiccator. 5.19 Vibration-free bench. 6 Sampling and preparatio
8、n of test sample If sufficient material is available, take a representative sample containing a minimum of 1 kg in the 5,6 mm to 2,8 mm size fraction. If there is insufficient material to provide the required amount in this size fraction, crush all the larger shale and add the 5,6 mm to 2,8 mm size
9、fraction of the crushed product to that size fraction in the original material. If neither of these measures provides sufficient material, a size fraction of 5,6 mm to 1.0 mm shall be used instead. Full de- tails of the sample taken shall be included in the test report (see clause 10). NOTES 5 It ma
10、y be useful to prepare and test separate represen- tative samples from the floor, roof and dirt bands for each seam. 6 If the test sample is obtained from raw coal by means of float and sink separation, this may affect the results of the test. Remove the dust from the test sample by gentle blowing w
11、ith air and store the test sample, until re- quired for testing, in a secure, sealed container. 7 Procedure 7.1 Determination of initial moisture content Determine the moisture content of the shale “as re- ceived” by weighing a IO Q portion, to an accuracy of f 0,000 1 g, drying in the oven (5.14) f
12、or 2 h at 105 “C to 110 “C and then reweighing. 7.2 Preparation of test portion Dry for 2 h in the oven (5.14), at 105 “C to 110 “C, enough of the test sample to provide a mass of 120 Q, when dried, and place it in a sealed container. 7.3 Determination of residual moisture content Determine the resi
13、dual moisture in the test portion by taking 10 g of the dried test sample (see 7.2), 3 IS0 10753:1994(E) Q IS0 weighed to an accuracy of f 0,000 1 g, drying in the oven (5.14) to constant mass at 105 “C to 110 “C and then reweighing. 7.4 Agitation of test portion Weigh, to an accuracy of f 0,Ol g, 1
14、00 g of the dried test sample (7.2), place in the cylindrical jar (5.1) and add 500 ml of water (clause 4). Seal the jar securely, place it in the rotation machine (5.2) and rotate it about a transverse axis (i.e. “end over end”) at a ro- tational frequency of 40 min- f 1 min- (speed of 40 r/min f 1
15、 r/min) for 30 min. 7.5 Sieving of suspension Locate the funnel (5.4) in the neck of one of the measuring cylinders (5.8) and mount the 500 pm test sieve (5.3) in the funnel. Sieve the suspension result- ing from the agitation (7.4) through the test sieve, taking care to ensure that the solids are d
16、istributed evenly over the surface of the sieve. Use 250 ml of water (clause 4) to rinse out the jar and wash the residue on the sieve, applying the water by means of the wash bottle (5.17). Remove the sieve from the funnel, place it on the tray (5.5) and dry in the oven (5.14) at 105 “C to 110 “C f
17、or 1 h. Remove the tray containing the sieve from the oven. Brush off the dried material into the tared con- tainer (5.6) and dry in the oven to constant mass (see note 7). Cool in the desiccator (5.18), to prevent ab- sorption of moisture, and weigh to an accuracy of f 01 g. NOTE 7 If the operation
18、 of drying to constant mass is likely to take more than 30 min, the mass measured at that time should be recorded and used to calculate the concen- tration of solids in the suspension passing through the sieve (see 7.8). This procedure is used in order that the proportion of material that is below a
19、 nominal particle size of 10 pm may be determined with the minimum of delay. 7.6 Treatment of fines While the material retained on the sieve is being dried, rinse any fine particles adhering to the funnel into the measuring cylinder containing the suspension that has passed through the sieve, using
20、100 ml of water (clause 4). Dilute to 1 litre and place the measuring cylinder in the thermostatically-controlled bath (5.13). 7.7 Preparation of water and apparatus for sedimentation Fill the flask (5.12) with water (clause 4) and place it, together with the sedimentation apparatus (5.9), in the th
21、ermostatically-controlled bath (5.13), main- tained, to within f 0.2 “C, at a temperature close to ambient temperature. Allow at least 1 h to reach temperature equilibrium before proceeding with the procedure described in 7.8. Use this water whenever water is required for subsequent steps in the pro
22、- cedure. 7.8 Adjustment of concentration of suspension Calculate the percentage of material passing through the 500 pm test sieve in accordance with 8.1, using the approximate mass of material retained on the sieve if necessary (see note 7). From this percentage, and the mass of the test portion (s
23、ee 7.4), determine the concentration of solids in the suspension obtained as described in 7.6. If this concentration does not ex- ceed 20 g/l, use the suspension directly for the sedimentation (see 7.10). Otherwise, invert the cylin- der six times to mix its contents, transfer an appro- priate volum
24、e to the second measuring cylinder (5.8) and dilute to volume with water maintained as de- scribed in 7.7. Keep the measuring cylinder, contain- ing the suspension to be used for the next step, in the thermostatically-controlled bath (5.13). NOTE 8 The concentration of the solids in the suspen- sion
25、 is adjusted to a level at which the particles may be as- sumed to be in free settlement, without mutual hindrance. The actual volume taken from the first measuring cylinder for dilution to 1 litre is not critical, provided that it is meas- ured accurately. If the suspension in the first measuring c
26、ylinder contains m g of solids, a measured volume of not more than 2.0 x lo4 ml should be transferred to the sec- ond measuring Cylinder. 7.9 Determination of settling time Calculate the time r, in seconds, taken for particles of 10 pm nominal diameter to fall 100 mm, from the following equation: t = 1,223 x 1 06q . (1) where t is the dynamic viscosity of water, in Pascal seconds, at the temperature of the test). 1) The dynamic viscosity of water at different temperatures can be obtained from reference tables, e.g. Tables of physical and chemical constants, G.W.C. Kaye and T.H. Laby. 4
