International Journal of Coal Preparation and Utilization
ISSN: 1939-2699 (Print) 1939-2702 (Online) Journal homepage: http://www.tandfonline.com/loi/gcop20
Optimization of Teetered Bed Separator Using Pulsed Water Yaowen Xing, Xiahui Gui, Yongtian Wang, Yijun Cao & Yi Zhang To cite this article: Yaowen Xing, Xiahui Gui, Yongtian Wang, Yijun Cao & Yi Zhang (2015): Optimization of Teetered Bed Separator Using Pulsed Water, International Journal of Coal Preparation and Utilization, DOI: 10.1080/19392699.2015.1061515 To link to this article: http://dx.doi.org/10.1080/19392699.2015.1061515
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Date: 08 March 2016, At: 19:41
Optimization of teetered bed separator using pulsed water Yaowen Xing1, Xiahui Gui2, Yongtian Wang2 , Yijun Cao2, Yi Zhang1 1
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School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China, 2Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou, Jiangsu, China Address correspondence to Xiahui Gui, Chinese National Engineering Research Center of Coal Preparation and Purification, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China. E-mail:
[email protected]
Abstract The teetered bed separator (TBS) is widely used for coal particles with a size range of 2.0 mm to 0.25 mm separation based on hindered settling principles. However, a problem with teeter-bed units is the limited range of particle size in which an acceptable separation performance is achieved. To explore the probability of extend size range of TBS, a pulsed water supply with different frequencies and amplitudes was introduced to the traditional TBS in this study. The separation performance of 2 mm to 1 mm coarse fraction and 1 mm to 0.25 mm fine fraction were systematically compared with and without pulsed water, respectively. The results show that, for 2 mm to 1 mm coarse fraction, little additional benefit was gained when pulsed water was used to supply the fluidization water to a traditional TBS. However, for a fine fraction of 1 mm to 0.25 mm, an optimal separation index—89.18% combustible recovery with 11.58% ash content and 468.41 efficiency index—was obtained when the frequency and amplitude
1
were 1 Hz and 40 dm3/h, respectively. The efficiency index under pulsed water condition increased by 80.45, compared with that of constant upward water. It indicates that the bed was completely loosened through the forced oscillation and constant friction collision among the particles in the bed under the interaction of pulsed and continuous flow. The
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fine mud mechanical entrainment phenomenon in traditional TBS was avoided. Therefore, pulsed water can reduce the lower particle size limit, which means that the upper limit size of the flotation feeding decreases. The amount of materials entered into flotation process also decreases, reducing the cost of actual industrial production.
KEYWORDS: coarse coal, Teetered Bed Separator, constant water, pulsed water
1. INTRODUCTION The teetered bed separator (TBS) is widely used for coal particles with a size range of 2.0 mm to 0.25 mm separation based on hindered settling principles. An upward current of water fluidizes a bed of particles including coal and ash-based minerals, thereby producing an autogenous medium that is suitable for separating the coal feed based on density. The light fractions overflow a launder and represent the clean product. Only the heaviest particles in the feed can pass through the particle bed and report to the underflow stream [1–2]. A problem with teeter-bed units is the limited particle size range in which an acceptable separation performance is achieved. Coarse with low ash content and fine particles with high ash may not be efficiently separated in TBS [3–5]. The high-
2
efficiency separation of coal particles with a size range of 2.0 mm to 0.25 mm is one of the current research topics in the field.
The separation process and flow behavior of coarse coal slime in the liquid–solid
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fluidized bed has been extensively studied [6–12]. In case the feed is rich in the easy-toseparate type of binary systems, then the liquid–solid technique is the best option, and process efficiency is usually high. A feed that contains a higher proportion of difficult-toseparate type of binary systems requires the optimization of the operating parameters in a liquid–solid fluidization separator to enhance the separation efficiency [13]. Numerous investigators have attempted to optimize TBS performance. A spiral unit that can provide an upward force for the upward movement of low-density coal particles into concentrate was introduced into the conventional TBS. The quantity of water addition for fluidization water was significantly decreased [14]. The HydroFloat separator, an air-assisted fluidized-bed separator, was used to deal with coarse coal slime. The hydrophobic species attached to air bubbles to form bubble-particle aggregates, which in turn reduced their effective density. The recoveries obtained by the aerated fluidized-bed separator in most cases were significantly higher than those obtained by the mechanically agitated flotation cell [15–20].
A laboratory-scale TBS, with jigging facility, was continuously operated by Galvin et al to process a feed that contained coal and mineral matter [21]. A similar separation
3
performance was obtained, and little additional benefit was gained when a cyclic pulse was used to supply the fluidization water to a TBS. However, the separation efficiency of the fine particle appeared to improve slightly when jigging was applied. It should be noted that a wide size range fraction (2-0.25 mm) was directly chosen as the feeding in
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Gavin’s investigation. Then the products were sieved into different size ranges and analyzed for ash content. Finally, separation results of different size fractions were obtained. However, the separation performance was influence by interaction effect of different size fractions. And the different size fractions may not in the optimal separation condition because separation based on density of TBS was significantly affected by a wide size range. The effect of different frequencies and amplitudes on separation performance still requires a systematic study. The mathematical models for liquid pulsed particulate fluidization and its dynamic processes were also studied. The local equilibrium model was proposed to describe the liquid pulsed fluidization with acceptable engineering accuracy as compared with the experimental data [22]. However, the behavior of particles with a wide range of sizes in the TBS is complex and not well understood. The present investigation was undertaken as part of the efforts to seek a highefficiency separation method for coarse coal slime cleaning.
Pulsed fluidization is of considerable interest in process engineering for improving fluidization quality [22]. To explore the probability of extending the particle size range of TBS, a pulsed water supply with different frequencies and amplitudes was introduced to
4
traditional TBS. In present study, two narrow size fractions (i.e., 2-1 mm and 1-0.25 mm) were directly separated by traditional and pulsed TBS, respectively. The effect of interaction in the designed test is tiny. Narrow size feeding was more suitable for TBS according to the hindered settling theory. It can ensure that different size
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fractions were all keep at the optimal separation condition. The separation performance for a coarse fraction of 2 mm to 1 mm and that for a fine fraction of 1 mm to 0.25 mm were systematically compared with and without pulsed water, respectively. The intensification mechanism of pulsed water was also analyzed initially.
2. EXPERIMENTAL 2.1. Materials Dry low rank coal samples (long flame coal) of 2-0 mm fraction as received were obtained from Suancigou Coal Preparation Plant, Inner Mongolia, China. An SPB-Ф 200 vibration sieve machine was used for 1 mm dry screening of raw coal, while 0.25 mm wet screen was conducted to remove -0.25 mm fraction. The results of the float–sink tests for the fractions of 2 mm to 1 mm and 1 mm to 0.25 mm are shown in Table 1 and Table 2, respectively. The density compositions of the two size fractions are similar to that of a uniform distribution. It indicates that a yield of 77.87% with an ash content reaching 14.08% can be obtained at a separation density of 1.8 g/cm3 for the size fraction of 2 mm to 1 mm. A yield of 74.87% with an ash content reaching 13.79% can also be obtained at a separation density of 1.8 g/cm3 for the size fraction of 1 mm to 0.25 mm. It should be
5
noted that the density of the coal (minus the mineral matter) is higher which makes the density separation more difficult. There is more 1.4-1.5 g/cm3 material than -1.3 and 1.3 1.4 g/cm3 material.
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2.2. Experimental System Design A laboratory-scale TBS used in this experiment was 0.11 m in diameter and 1.8 m in height and has two main parts: a coal separation system and a pulsed upward water control system. A diagram of the experiment device is shown in Fig. 1. A frequency converter can receive the 0 mV to 20 mV signal produced by the programmable logic controller (PLC). The upward water control system can achieve the function of both steady and pulsed water at various sine wave supply levels. The water flow rate was measured using a rotameter. The bed pressure was measured using a pressure sensor and was used to control the underflow discharge rate. The feeding speed and solid content were kept constant at 2.2 kg solid per minute and 450 g/L, respectively. Concentrates and tailings were collected, filtered, and dried for ash analysis.
2.3. Performance Measures The combustible recovery was used to evaluate the separation performance. It was calculated using Eq. (2-1) and Eq. (2-2):
j
%
Ad f
Adt
Adc
Adt
100
(2-1)
6
Combustible recovery (%) =
j
100 Adc
100 (2-2)
100 100 Ad f
where Ad f , Ad c and Ad t are the ash contents of the feed, concentrates and tailings,
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respectively.
j
is the yield of the concentrates.
Another important response parameter used in the study was the separation efficiency index, which was used to compare the relative performance of gravity based on the cleaning operations under various operating conditions and to determine the optimum separation performance [23]. Separation efficiency index =
j
Ad t Ad c
(2-3)
3. RESULTS AND DISCUSSION 3.1. Separation Performance For The Fraction Of 2 Mm To 1 Mm With And Without Pulsed Water The separation results for the coarse fraction of 2 mm to 1 mm without pulsed water are shown in Table 3.Under the condition of constant upward water, concentrate yield, ash content, and combustible recovery increased as upward water quantity increased when bed pressure was held constant. It means that high upward water quantity can produce a high separation density. However, with upward water quantity increasing, the efficiency index initially increased before reaching a maximum value, after which it decreased. An
7
increase in the upward water velocity expands the particle bed thereby reducing the effect of particle density and increasing the impact of particle size. As a result, fine particles containing high ash content were recovered in the clean coal. The concentrate yield, ash content, and combustible recovery increased monotonously with the increase of bed
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pressure when upward water quantity was held constant. The increased of bed pressure mean that bed solid phase volume concentration increased, which lead to a high separation density. Similarly, separation efficiency decreased sharply with excessive high bed pressure. In this study, the optimal separation performance, an ash content of 11.35%,83.13% combustible matter recovery and 379.21 efficiency index, could be obtained when the upward water quantity and bed pressure were 344 dm3 /h and 17.8 kPa, respectively.
Six sine waveforms of upward water were introduced to the traditional constant upward water TBS under optimal operating condition (344 dm3/h upward water quantity and 17.8 kPa bed pressure) to explore the benefit of pulsed water in the separation performance for a coarse fraction of 2 mm to 1 mm. The water flow rate was proportional to the frequency of converter. Firstly, six sine waveforms of frequency were produced through the PLC program. Then the corresponding upward water velocity was calculated. As shown in Eq. 3-(1-6), the straight line Q=344 dm3/h was defined as symmetric axis for six sine waveforms which indicated that the average upward water velocity was kept constant at 344 dm3/h in a complete cycle. Two different amplitudes (i.e., 40 and 80 dm3/h) and three
8
frequencies (i.e., 0.25, 0.5 and 1 HZ) were combined, respectively. The bed pressure was held constant at 18.6 kPa. The separation result for the coarse fraction of 2 mm to 1 mm with pulsed water is shown in Table 4. And the comparison of conventional and pulsed
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TBS results with respect to the washability data for 2-1 mm fraction is shown in Fig. 2.
Q1 dm3 / h
40sin
Q2 dm3 / h
40sin t 344 (3-2)
Q3 dm3 / h
40sin 2 t 344 (3-3)
Q4 dm3 / h
80sin
Q5 dm3 / h
80sin t 344 (3-5)
Q6 dm3 / h
80sin 2 t 344 (3-6)
2
2
t 344 (3-1)
t 344 (3-4)
As shown in Table 4 and Fig. 2, little benefit was gained when pulsed water was used to supply the fluidization water to a TBS for the coarse fraction of 2 mm to 1 mm, compared with the optimal separation performance with constant upward water. For instance, a combustible matter recovery of 84.58% with 382.38 maximum efficiency index was obtained when the frequency and amplitude were 1 Hz and 40 dm3 /h, respectively. By contrast, when the amplitude was too large, the bed stability may be damaged result in a decrease of separation efficiency. It indicates that some larger particles with low density may be lost in the tailings. When frequency and amplitude are 1 Hz and 80 dm3/h, the combustible matter recovery and efficiency index dramatically decreased to 75.94% and 359.37, respectively. An additional separation mechanism, which is referred to as the
9
jigging for pulsed water, may produce a satisfactory separation index. However, such separation is not much better than can be achieved by steady fluidization at a high suspension density when dealing with the coarse fraction of 2 mm to 1 mm. The same
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result was found by Galvin et al [21].
3.2. Separation Performance For The Fraction Of 1 Mm To 0.25 Mm With And Without Pulsed Water The separation results for the fine fraction of 1 mm to 0.25 mm without pulsed water are shown in Table 5. The results are similar to those in Table 3.The concentrate yield, ash content, and combustible recovery show an increasing trend as upward water quantity increased when bed pressure was held constant. The efficiency index initially increased and then decreased with upward water quantity increasing. Also, concentrate yield, ash content, and combustible recovery increased monotonously with the increase of bed pressure. The efficiency index decreased with excessive high bed pressure. An optimal separation performance, 13.26% ash content, 87.21% combustible recovery and 387.96 efficiency index, could be obtained when the upward water quantity and bed pressure were 344 dm3/h and 17.8 kpa, respectively.
However, different separation performance for the fine fraction of 1 mm to 0.25 mm can be observed compared with those for the coarse fraction of 2 mm to 1 mm, when the same pulsed water waveforms were applied to constant upward water TBS under the
10
above mentioned optimum operating conditions. The results are shown in Table 6 and Fig. 3. When the amplitude of pulsed water was kept constant, the combustible matter recovery and efficiency index increased monotonously with the increase of pulsed frequency, whereas the concentrate ash content decreased. Meanwhile, an increase in
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amplitude deteriorated the separation performance. This result is mainly caused by the destruction of the bed stability. An optimal separation index—89.18% combustible recovery with 11.58% ash content and 468.41 efficiency index, was obtained when frequency and amplitude were 1 Hz and 40 dm3/h, respectively. As shown in Fig. 3, the optimal separation performance point of pulsed TBS is closed to theoretical yield curve and can produce better clean coal in terms of lower ash content and higher yield. The combustible recovery and efficiency index under pulsed water condition increased by 1.97% and 80.45, respectively, compared with those of constant upward water. This result indicates that a lower separation bed density might be produced by pulsed water. Under the interaction of pulsed and continuous flow, the bed was completely loosened through the forced oscillation and constant friction collision between the particles in the bed. The fine mud mechanical entrainment phenomenon was avoided in the traditional TBS. Thus, pulsed water was beneficial in improving the fluidization quality and separation accuracy of the fine fraction of 1 mm to 0.25 mm. Pulsed water provided a probability of the lower limit size of TBS feeding decreasing, which means that the upper limit size of the flotation feeding decreases. The amount of materials entered into flotation process also decreases, reducing the cost of actual industrial production.
11
4. CONCLUSION 1. For the coarse fraction of 2 mm to 1 mm, little benefit was gained when pulsed water was used to supply the fluidization water to a TBS for the coarse fraction of 2 mm to 1 mm, compared with the optimal separation performance with constant
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upward water. An additional separation mechanism referred to as jigging for pulsed water may produce a satisfactory separation index. However, such separation is not much better than can be achieved by steady fluidization at a high suspension density when dealing with the coarse fraction of 2 mm to 1 mm. 2. For the fine fraction of 1mm to 0.25 mm, an optimal separation index—89.18% combustible recovery with 11.58% ash content and 468.41 efficiency index, was obtained when frequency and amplitude were 1 Hz and 40 dm3 /h. The combustible recovery and efficiency index under pulsed water condition increased by 1.97% and 80.45, respectively, compared with those of constant upward water. Under the interaction of pulsed and continuous flow, the bed was completely loosened through the forced oscillation and constant friction collision between the particles in the bed. The fine mud mechanical entrainment phenomenon was avoided in the traditional TBS. Thus, pulsed water was beneficial in improving the fluidization quality and separation accuracy of the fine fraction of 1 mm to 0.25 mm. 3. Pulsed water provided a probability of the lower limit size of TBS feeding decreasing, which means that the upper limit size of the flotation feeding
12
decreases. The amount of materials entered into flotation process also decreases, reducing the cost of actual industrial production. However, the intensification mechanism of pulsed water for different size fractions requires further study.
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ACKNOWLEDGEMENTS This research was supported by the National Nature Science Foundation of China (Grant no.51304192), the Project funded by China Postdoctoral Science Foundation (2014M550317) and Guizhou "125 plan" key project of science and technology project(No.Qian jiao he zhong da zhuang xiang zi [2013] 026) for which the authors express their appreciation.
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[4] Li Y., 2008. Study on the Separation Mechanism and Application of Liquid– Solid Fluidized Bed Coarse Slime Separator. China University of Mining and Technology, Xuzhou. [5] Sha J., Xie G., Peng Y.L., Shi B.X., 2011. Hydrodynamics of coarse coal slime and
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quartz particles in a liquid-solid fluidized bed separator. Solid Mechanics and Materials Engineering 279: 350- 355. [6] Honaker, R.Q., Mondal, K., 2000. Dynamic Modeling of Fine Coal Separations in a Hindered-bed Classifier. International Journal of Coal Preparation and Utilization 21: 211-232. [7] Gui X., Li Y., Liu J., Wang Y., Cao Y., 2010. Study on settlement characteristic of the grain in fluidized bed. Journal of China Coal Society 35(8):1374- 1379. [8] Ganguly, U.P., 1986. Elutriation characteristics of solids from liquid-solid fluidized bed systems; part iii: a study of the possible causes of non-linearity in the elutriation of fine particles from fluidized beds. Canadian Journal of Chemical Engineering 64 (1): 171-174. [9] Zhang K., Wu G., Brandani, S., Chen H., Yang Y., 2012. CFD simulation of dynamic characteristics in liquid-solid fluidized beds. Powder Technology 227:104-111. [10] Doroodchi, E., Galvin, K.P., Fletcher, D.F., 2005.The influence of inclined plates on expansion behaviour of solid suspensions in a liquid fluidised bed-a computational fluid dynamics study, Powder Technology 156: 1-7.
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[11] Jena, H.M., Roy, G.K., Meikap, B.C., 2009. Hydrodynamics of regular particles in a liquid-solid semi-fluidized bed. Powder Technology 196: 246-256. [12] Kechroud, N., Brahimi, M., Djati, A., 2010. Characterization of dynamic behaviour of the continuous phase in liquid fluidized bed, Powder Technology 2010:149-157.
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[13] Mukherjee, A.K., Kumar, A., 2009. Liquid/solid fluidization its role and limitation in fine beneficiation-a review. Mineral Processing and Extractive Metallurgy Review 30 (3):280- 306. [14] Sha J., Liang L., Liu B., Xie G., Peng Y., 2015. Design and experiments using a spiral liquid-solid fluidized bed system. Physicochemical Problems of Mineral Processing 51:427-434. [15] Bellson Awatey, Homie Thanasekaran, Kohmuench, J.N. et al., 2014. Critical contact angle for coarse sphalerite flotation in a fluidised-bed separator vs. a mechanically agitated cell. Minerals Engineering 60:51-59. [16] Bellson Awatey, Homie Thanasekaran, Kohmuench, J.N. et al., 2013. Optimization of operating parameters for coarse sphalerite flotation in the HydroFloat fluidised-bed separator. Minerals Engineering 50-51: 99-105. [17] Kohmuench, J., Thanasekaran, H., Seaman, B. 2013. Advances in coarse particleflotation: copper and gold. In: Plant Design and Operating Strategies-World’s Best Practice (MetPlant 2013), 15-17 July, Perth, Western Australia.
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[18] Luttrell, G.H., Westerfield, T.C., Kohmuench, J.N., Mankosa, M.J., Mikkola, K.A., Oswald, G., 2006. Development of high-efficiency hydraulic separators. Miner. Metall. Process 23:33-39. [19] Jameson, G.J., 2010. New directions in flotation machine design. Minerals
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Engineering 23: 835-841. [20] Jameson, G.J., 2008. Method and Apparatus for Flotation in a Fluidized Bed. PCT Patent Application No. WO 2008/104022, 4 September. [21] Galvin, K.P., Pratten, S.J., Lambert, N., Callen, A.M., Lui J., 2002. Influence of a jigging action on the gravity separation achieved in a teetered bed separator. Minerals Engineering 15:1199-1202. [22] Jin G., Liu D., 2005. Modeling and simulation of liquid pulsed particulate fluidized beds. Powder Technology 154:138-155. [23] Mohanty, M.K., Honaker, R.Q., Govindaratan, B., 1999. Development of a characteristic flotation cleaning index for fine coal. International Journal of Mineral Processing 55:231-243.
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Table 1 Density analysis data of samples of 2-1 mm fraction Cumulative of
Cumulative of
floating objects
sediments Yield ,%
Density
Yield, Ash
Yield,
Ash
fractions
%
%
,%
,g/cm3
content
Ash ,%
Content of δ±0.1
Density,
Yield
g/cm3
,%
,%
-1.3
5.1
4.13
5.10
4.13
100.00
29.86
1.30
20.88
-1.3+1.4
15.78
6.42
20.88
5.86
94.90
31.25
1.40
39.23
-1.4+1.5
23.45
7.65
44.33
6.81
79.12
36.20
1.50
40.56
-1.5+1.6
17.11
15.16
61.44
9.13
55.67
48.22
1.60
25.33
-1.6+1.8
16.43
32.56
77.87
14.08
38.56
62.89
1.70
16.43
+1.8
22.13
85.41
100.00 29.86
22.13
85.41
Total
100
29.86
17
Table 2 Density analysis data of samples of 1-0.25 mm fraction Ash
Cumulative of
Cumulative of
Content of
content
floating objects
sediments
δ±0.1
Yield
Ash
Density,
Yield
,%
,%
g/cm3
,%
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,% Density
Yield,
Yield,
fractions
%
%
Ash ,%
,g/cm3 -1.3
3.9
4.32
3.90
4.32
100.00
32.24
1.30
18.87
-1.3+1.4
14.97
6.01
18.87
5.66
96.10
33.38
1.40
39.53
-1.4+1.5
24.56
7.31
43.43
6.59
81.13
38.43
1.50
42.18
-1.5+1.6
17.62
15.98
61.05
9.30
56.57
51.94
1.60
24.53
-1.6+1.8
13.82
33.64
74.87
13.79
38.95
68.20
1.70
13.82
+1.8
25.13
87.21
100.00
32.24
25.13
87.21
Total
100
32.24
18
Table 3 Separation results for 2-1 mm fraction without pulsed water
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Concentrate
Tailings
Upward
Bed
Ash
Yield（
Ash
Yield（ Combu
water
pressure
content（
%）
content（%
%）
quantity(
(kpa)
%）
）
264
344
424
ncy
recover index
dm3/h) 184
stible
Efficie
y(%) 17.4
6.56
31.35
40.51
68.65
41.76
193.60
17.8
8.98
55.96
56.45
44.04
72.62
351.78
18.2
9.78
59.33
59.16
40.67
76.32
358.89
17.4
8.02
52.73
54.23
47.27
69.15
356.55
17.8
10.13
60.41
59.99
39.59
77.40
357.75
18.2
11.84
66.97
66.42
33.03
84.18
375.69
17.4
10.56
63.14
62.97
36.86
80.51
376.51
17.8
11.35
65.77
65.44
34.23
83.13
379.21
18.2
13.23
70.07
68.83
29.93
86.68
364.54
17.4
12.35
68.32
67.74
31.68
85.38
374.74
17.8
13.77
70.16
68.01
29.84
86.25
346.52
18.2
15.65
73.12
69.37
26.88
87.93
324.11
19
Table 4 Separation results for 2-1 mm fraction with pulsed water Concentrate
Tailings
Frequenc
Amplitude
Ash
Yield
Ash
Yield（
Comb
Efficie
y(HZ)
(dm3/h)
content（
（%）
content
%）
ustible
ncy
recove
index
（%）
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%）
ry(%) 0.25
40
11.47
65.17
64.49
34.83
82.26
366.42
0.5
40
11.67
64.79
63.46
35.21
81.59
352.32
1
40
11.65
67.15
66.34
32.85
84.58
382.38
0.25
80
11.01
64.57
64.26
35.43
81.92
376.86
0.5
80
10.26
62.18
62.04
37.82
79.56
375.99
1
80
9.67
58.97
58.93
41.03
75.94
359.37
20
Table 5 Separation results for 1-0.25 mm fraction without pulsed water
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Concentrate
Tailings
Upward
Bed
Ash
Yield
Ash
Yield（ Combu
water
pressure
content（
（%）
content（ %）
stible
quantity(
(kpa)
%）
%）
recover
dm3/h) 184
264
344
424
Efficiency index
y(%) 17.4
7.25
47.14
55.96
52.86
64.53
363.86
17.8
9.68
56.45
63.25
43.55
75.24
368.85
18.2
12.15
65.48
72.51
34.52
84.89
390.78
17.4
10.07
58.73
64.63
41.27
77.95
377.12
17.8
11.16
62.35
68.17
37.65
81.75
380.86
18.2
13.01
67.32
74.18
32.68
86.43
383.84
17.4
12.01
64.71
71.49
35.29
84.03
385.19
17.8
13.26
68.12
75.49
31.88
87.21
387.96
18.2
15.13
72.12
78.89
27.88
90.33
376.04
17.4
13.66
68.34
74.71
31.66
87.08
373.77
17.8
15.12
72.44
79.96
27.56
90.74
383.09
18.2
16.75
74.63
80.91
25.37
91.69
360.50
21
Table 6 Separation results for 1-0.25 mm fraction with pulsed water Concentrate
Tailings
Frequenc
Amplitude
Ash
Yield
Ash
Yield（ Comb
y(HZ)
(dm3/h)
content（
（%）
content（
%）
Downloaded by [China University of Mining Technology] at 19:42 08 March 2016
%）
%）
Efficien
ustible
cy
recove
index
ry(%) 0.25
40
13.45
66.18
71.26
33.82
84.53
350.63
0.5
40
12.24
67.47
76.10
32.53
87.38
419.48
1
40
11.58
68.34
79.37
31.66
89.18
468.41
0.25
80
14.94
64.17
65.37
35.83
80.55
280.78
0.5
80
14.43
66.18
69.43
33.82
83.57
318.43
1
80
13.14
67.91
75.15
32.09
87.05
388.39
22
Downloaded by [China University of Mining Technology] at 19:42 08 March 2016
Figure 1. Schematic diagram of experiment device.
23
Figure 2. The comparison of conventional and pulsed TBS results with respect to the
Downloaded by [China University of Mining Technology] at 19:42 08 March 2016
washability data for 2-1 mm fraction.
24
Figure 3. The comparison of conventional and pulsed TBS results with respect to the
Downloaded by [China University of Mining Technology] at 19:42 08 March 2016
washability data for 1-0.25 mm fraction.
25
