1、INTERNATIONAL STANDARD ISO 10086-1 First edition 2000-06-15 Reference number ISO 10086-1:2000(E) ISO 2000 Coal Methods for evaluating flocculants for use in coal preparation Part 1: Basic parameters Charbon Mthodes dvaluation des floculants utiliss dans la prparation des charbons Partie 1: Paramtres
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7、Contents Page 1 Scope . 1 2 Normative references . 1 3 Principle 1 4 Apparatus . 1 5 Materials . 2 6 Sampling . 3 7 Preparation of flocculant solutions 3 8 Procedure . 4 9 Calculation of results 5 10 Recording of results 6 11 Repeatability . 6 12 Test report 6 Annexes A Worked example . 8 B Data rec
8、ording sheets. 11 B.1 Free-settling rate . 11 B.2 Full settling curve 12ISO 10086-1:2000(E) iv ISO 2000 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internationa
9、l Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO,
10、also take part in the work. ISO collaborates closely with the International Electrotechnical Commis- sion (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Draft International Standards
11、adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this part of ISO 10086 may be the su
12、bject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 10086-1 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels,Subcom- mittee SC 1, Coal preparation: Terminology and performance. ISO 10086 consists of the
13、 following parts, under the general title Coal Methods for evaluating flocculants for use in coal preparation: Part 1: Basic parameters Part 2: Flocculants as filter aids in vacuum filtration Annexes A and B of this part of ISO 10086 are for information only.INTERNATIONAL STANDARD ISO 10086-1:2000(E
14、) ISO 2000 All rights reserved 1 Coal Methods for evaluating flocculants for use in coal preparation Part 1: Basic parameters 1 Scope This part of ISO 10086 specifies a method for the comparative evaluation of the performances of flocculants for clarification, thickening and sedimentation applicatio
15、ns on a given slurry. This performance can be evaluated by a) the settling velocity in the initial period, b) the sediment volume after compaction and consolidation, c) the clarity of the supernatant liquid. 2 Normative references The following normative documents contain provisions which, through r
16、eference in this text, constitute provisions of this part of ISO 10086. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 10086 are encouraged to investigate the possibility of applying th
17、e most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 1171, Solid mineral fuels Determination of ash. ISO 1
18、953, Hard coal Size analysis by sieving. 3 Principle The performance of different flocculants on a given slurry is determined by measuring the relative settling rates. A flocculant solution is added to an aliquot of the slurry in a measuring cylinder and the formation of an interface between the sup
19、ernatant liquid and the suspension is observed. An initial settling rate is calculated and is plotted against flocculant dosage to evaluate the performance of the flocculant. 4A p p a r a t u s Usual laboratory apparatus, and 4.1 Stirrers, two variable-speed motorized stirrers capable of (one for fl
20、occulant preparation and one for sample homogenization). 4.2 Plastic moulded cylinders, of capacity , graduated in scale divisions and having rubber stoppers. Where these are not available, glass cylinders, of capacity , graduated in scale divisions and having ground-glass stoppers, may be a satisfa
21、ctory alternative. However, differences in settling rates may result, because of differences in the graduated height. 1 000 r/min 500 ml 5 ml 500 ml 2ml 5mlISO 10086-1:2000(E) 2 ISO 2000 All rights reserved A vertical scale may be attached to or mounted beside the cylinder, with the zero point coinc
22、iding with the mark of the cylinder. 4.3 Syringes, having nominal capacities of , , , and . 4.4 Timer, capable of reading to a total of . 4.5 Clarity wedge, as shown in Figure 1, having a scale in black numbers on a white background (or vice versa) printed inside the back. 5M a t e r i a l s 5.1 Slu
23、rry Flocculant evaluation shall be carried out on a slurry collected from the coal preparation plant and free from flocculant contamination. The sample shall be collected in at least 10 increments over a minimum of of stable operating conditions, to give a total sample volume of or more. Dimensions
24、in millimetres NOT TO SCALE Key 1 Transparent plastic sides and front Wall thickness: 2 Suspension level Figure 1 Clarity wedge 5ml 1ml 2ml 5ml 10ml 50ml 0,1 s 10 000 s 4mm 2h 50 litresISO 10086-1:2000(E) ISO 2000 All rights reserved 3 The sample shall be collected in a container that is inert to th
25、e slurry and stored in a suitable environment that maintains a temperature of . Storage may affect the characteristics of the sample and, hence, affect the relative performance of the flocculants. Therefore, the sample shall be used as soon as possible, but not later than after collection. A size an
26、alysis and ash determination shall be performed on the solids in the sample using the methods given in and respectively. The concentration of solids in the slurry, in grams per litre on a dry basis, shall also be determined, by drying the sample in an oven at to constant mass, which is defined as th
27、e point at which two consecutive weighings do not differ by more than after intervals in the oven. The collected sample is divided into representative subsamples as follows. a) Mix the slurry using a motorized stirrer (4.1) to ensure homogeneity of the sample. b) While the sample is being stirred, d
28、ip a beaker of capacity into the slurry and fill it. Pour this sample into the first cylinder (4.2). Repeat the procedure, adding to each cylinder in a cyclic pattern, until sufficient test cylinders for complete test work are filled to the mark. 5.2 Water Prepare the flocculant solution using water
29、 that is used in the plant, where this is available. Where plant water is not available, use potable or fresh water. Collect sufficient water for all of the flocculants being tested. If flocculants are not currently being used by the plant, careful consideration should be given to a suitable source
30、of water. 6 Sampling Flocculants are available in the forms of powder, emulsion, dispersion or solution. In this part of ISO 10086, emulsion, dispersion and solution flocculants are referred to as liquid flocculants. Recommendations are as follows: a) Flocculants should be obtained as fresh samples
31、and should be discarded after six months. b) Store all flocculant samples at ambient temperature, away from direct sunlight and heat, and keep solid flocculant sampl esa w a yfr ommoi sture . c) Avoid unnecessarily opening and closing of the sample container. d) Take a sufficient quantity of floccul
32、ant sample for all of the tests to be carried out. 7 Preparation of flocculant solutions 7.1 Powder flocculants Homogenize the bulk portion of the flocculant by mixing. Using a scooped spatula, transfer a subsample of approximately of the flocculant, to at a time, into a weighing bottle. Place of wa
33、ter (5.2) in a beaker and stir the water at a speed that is sufficient to create a vortex. Sprinkle a preweighed amount of powder ( ) from the subsample onto the surface of the vortex and stir the resulting dispersion slowly until dissolution is complete, and for not less than . Use this stock solut
34、ion within . 20 C 2 C 24 h 105 C 5% 1h 500 ml 50 ml 500 ml 1 g 0,1 g 0,2 g 250 g 0,5 g 500 ml 0,25 g 0,01 g 1 g 2h 24 hISO 10086-1:2000(E) 4 ISO 2000 All rights reserved 7.2 Liquid flocculants Homogenize the sample in its container, then fill a syringe (4.3) with the liquid flocculant and weigh to t
35、he nearest . Place of water (5.2) in a beaker and stir the water at a speed sufficient to create a vortex. Discharge the syringe into the vortex and reweigh the empty syringe. Continue to stir at this speed for , then stir for a further at a slower speed that is high enough to keep the solution agit
36、ated. Use this stock solution within . 8 Procedure 8.1 Preparation of test sample Prepare a test sample of slurry by filling the cylinder with slurry using the method described in 5.1. Stopper the cylinder and homogenize the slurry either by double-inverting the cylinder end over end for , or by mix
37、ing for with a stirrer. Using a syringe, add the appropriate quantity (e.g. ) of flocculant solution (see 7.1) to the surface of the slurry in the cylinder, stopper and mix well by double-inverting the cylinder or by stirring, until completely homogenized. Excessive mixing should be avoided, to prev
38、ent degradation of the flocculant. 8.2 Determination of settling rate 8.2.1 Free settling rate Stand the cylinder upright. Observe the definite interface that forms between the clear supernatant liquid and the bulk of the flocculated suspension. Record the time ( ) for the interface to descend from
39、the mark to the mark on the cylinder. Measure the distance ( ), in millimetres, between these two marks. The free settling rate , in metres per hour, is then calculated from the following equation: where is the distance between the marks, in millimetres; is the time, in seconds, for the interface to
40、 descend from to . Repeat the procedure using different volumes of the same flocculant solution. Where it is required to compare flocculants, repeat the test(s) for each flocculant being evaluated. 8.2.2 Full settling curve Where it is required to construct the full settling curve, it is necessary t
41、o monitor the position of the interface throughout its descent down the measuring cylinder. Start the timer immediately after the flocculant has been added to the slurry and position the cylinder upright after the agitation. Record the time for the interface to pass each subdivision. 2ml 0,01 g 200
42、g 5 g 500 ml 5 min 2h 24 h 1 min 1 min 2ml t s 450 ml 250 ml d V f V f = d t 3,6 d t 450 ml 250 ml 25 mlISO 10086-1:2000(E) ISO 2000 All rights reserved 5 From these measurements, calculate a series of settling rates, in metres per hour, and from them calculate the settling rates by the maximum aver
43、age procedure (see the note). NOTE The maximum average procedure averages the settling rates progressively and chooses the maximum average ( . During the flocculation process, an induction period is usually observed which can cause the initial appearance of the interface between supernatant liquid a
44、nd flocculated solids to be delayed. The induction period is followed by a period of free settling of solids and then by a period in which compaction takes place. The “maximum average procedure” takes into account this behaviour of the slurry. A worked example is given for information in annex A. Re
45、peat the procedure with different volumes of the same flocculant solution. Where it is required to compare flocculants, the test should be repeated on each flocculant being evaluated. 8.3 Determination of sediment height and supernatant clarity Thirty minutes after standing the cylinder upright, mea
46、sure the settled volume of the sediment, in millilitres. Then fill the clarity wedge (4.5) with the supernatant liquid by decantation. Determine the clarity using the clarity wedge, by observing the highest value visible through the liquid. 9 Calculation of results 9.1 Flocculant dosage rate The con
47、centration of the flocculant solution, in grams of flocculant per gram of solution, is given by the equation: (1) where is the mass of water in the beaker; is the mass of flocculant dissolved in the water; For the purpose of this calculation, it is assumed that a volume of of flocculant solution wei
48、ghs . The mass of the solids ( ), in grams, in of slurry is given by the equation: (2) where is the concentration of solids in the slurry, in grams per litre. The flocculant dosage rate , in kilograms of flocculant per tonne (which is equivalent to grams per kilogram), is given by the equation: (3)
49、where is the volume of flocculant solution used to dose a slurry suspension in the cylinder, in millilitres. The units of the dosage rate may also be expressed in kilograms of flocculant per tonne of dry solids. A max ) C = m F m W m W m F 1ml 1g m S 500 ml m S = 0,5 S S (D F ) D F = 2 000 m F V F m W S V FISO 10086-1:2000(E) 6 ISO 2000 All rights reserved 9.2 Worked example Mass of water ( ), in grams = 201,2 Mass of flocculant ( ), in grams = 0,23 Concentration of solids in the slurry ( ), in
