Electrostatic separation device

Abstract

An electrostatic separation device that separates conductive particles from a raw material containing conductive particles and insulating particles using electrostatic force, the electrostatic separation device including: a container in which a raw material layer made of the raw material is formed; a gas dispersion plate disposed on a bottom of the raw material layer; at least one vibration body disposed in the raw material layer on the same surface as the gas dispersion plate or higher than the gas dispersion plate; a fluidizing gas supply device for supplying a fluidizing gas that is guided from a bottom of the container into the raw material layer and passes through the gas dispersion plate to raise the raw material layer; an upper electrode disposed above the raw material layer; a lower electrode disposed in the raw material layer on the same surface as the gas dispersion plate or higher than the gas dispersion plate; a power supply device that applies a voltage between electrodes of the upper electrode and the lower electrode in a manner that one of the upper electrode and the lower electrode is a negative electrode and the other is a positive electrode and an electric field is generated between the electrodes; and a capturing device for capturing the conductive particles that fly from a surface of the raw material layer toward the upper electrode.

Description

TECHNICAL FIELD

[0001] The present application relates to an electrostatic separation device that separates electroconductive particles from a raw material mixed with the electroconductive particles and insulating particles. BACKGROUND

[0002] Conventionally, an electrostatic separation device that separates electroconductive particles from a raw material mixed with the electroconductive particles and insulating particles (non-electroconductive particles) using electrostatic force is known. Such an electrostatic separation device is used for separation of specific components from coal ash, waste (e.g., waste plastic, garbage, incineration ash, etc.), removal of food impurities, concentration of minerals, and the like. Patent Literature 1 discloses such an electrostatic separation device.

[0003] The electrostatic separation device disclosed in Patent Literature 1 has a flat bottom electrode and a flat mesh electrode having a plurality of opening portions provided above the bottom electrode, and a voltage is applied between the two electrodes to form a separation zone divided by electrostatic force between the two electrodes. Further, the bottom electrode is composed of a gas dispersion plate having gas permeability, a dispersion gas is introduced to the separation zone from the lower side of the gas dispersion plate, and at least one of the bottom electrode and the mesh electrode is imparted with vibration. Thus, the electroconductive particles in the raw material supplied to the separation zone are separated to the upper side of the separation zone through the opening portions of the mesh electrode. The electroconductive particles separated to the upper side of the separation zone are transported to a dust collector in the form of gas flow through a suction pipe and are recovered by the dust collector.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: Japanese Patent No. 3981014 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] The electrostatic separation device of the above-described Patent Literature 1 is limited to forming a thin raw material layer on the bottom electrode. Further, since the bottom electrode is vibrated together with a container in which the bottom electrode is installed, it is difficult to make the device large. For this reason, it is difficult to process a large amount of raw material at a time, which leaves room for improvement in terms of improving the processing capacity.

[0009] The present application has been achieved in view of the above-described circumstances, and aims to provide a configuration that can improve the processing capacity in an electrostatic separation device that separates electroconductive particles from a raw material mixed with the electroconductive particles and insulating particles using electrostatic force.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] An electrostatic separation device according to an embodiment of the present application is an electrostatic separation device that separates conductive particles from a raw material containing the conductive particles and insulating particles,

[0012] The electrostatic separation device includes:

[0013] a container in which a raw material layer composed of the raw material is formed;

[0014] a gas dispersion plate disposed at a bottom of the raw material layer;

[0015] at least one vibration body disposed in the raw material layer at the same surface as or above the gas dispersion plate;

[0016] a fluidizing gas supply device that supplies a fluidizing gas that is guided from a bottom of the container into the raw material layer and passes through the gas dispersion plate to raise the raw material layer;

[0017] an upper electrode disposed above the raw material layer;

[0018] a lower electrode disposed in the raw material layer at the same surface as or above the gas dispersion plate;

[0019] a power supply device that applies a voltage between electrodes of the upper electrode and the lower electrode in a manner that sets one of the upper electrode and the lower electrode as a negative electrode and the other as a positive electrode and causes an electric field between the electrodes; and

[0020] a capturing device that captures the conductive particles flying from a surface of the raw material layer toward the upper electrode.

[0021] Since the raw material that constitutes the raw material layer has a smaller particle diameter than a fluid medium (e.g., sand) that forms a general fluid layer, the raw material layer is easily fluidized by the fluidizing gas. When the raw material layer is fluidized, the raw material layer is not easily fluidized. Therefore, by providing the vibration body in the raw material layer as described above, the raw material layer can be prevented from being fluidized, and the fluid state of the raw material layer can be maintained. Thus, the electrodes and the raw material in the raw material layer can be brought into contact with each other, and the processing capacity of the electrostatic separation device can be improved.

[0022] Effects of the Invention

[0023] According to the present application, a configuration that can improve the processing capacity in an electrostatic separation device that separates conductive particles from a raw material containing the conductive particles and insulating particles using an electrostatic force can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1This diagram illustrates the overall structure of the electrostatic separation device according to an embodiment of the present invention.

[0025] Figure 2 This diagram illustrates a modified example of an electrostatic separation device in which an insulating particle detachment promotion device is provided in the capture device.

[0026] Figure 3 A top view showing the relationship between the direction of movement of the conveyor belt's conveyor surface and the direction of travel of the raw material.

[0027] Figure 4 This figure illustrates a modified example of an electrostatic separation device in which a lower electrode is provided within the raw material layer.

[0028] Figure 5 This is a diagram illustrating an example of the relationship between the potentials of multiple electrodes.

[0029] Figure 6 This is a diagram illustrating another example of the relationship between the potentials of multiple electrodes.

[0030] Figure 7 This diagram illustrates a modified example of an electrostatic separation device equipped with a vibrating excitation device.

[0031] Figure 8 This diagram illustrates a modified example of an electrostatic separation device that includes a vibrating body excitation device and a container vibration device. Detailed Implementation

[0032] Next, use Figure 1 The electrostatic separation device 1 according to the embodiments of the present invention will be described. Figure 1 This diagram illustrates the overall structure of the electrostatic separation apparatus 1 according to an embodiment of the present invention. The electrostatic separation apparatus 1 according to this embodiment is an apparatus for primarily separating conductive particles 16 from a raw material 17 doped with conductive particles 16 and insulating particles 18. For example, this electrostatic separation apparatus 1 can be used to separate unburned carbon from coal ash (raw material 17) containing unburned carbon (conductive particles 16) and ash (insulating particles 18). However, the application of the electrostatic separation apparatus 1 is not limited to the above; it can also be used for the separation of various particles or powders, such as separating metals from waste, removing impurities from mercury, minerals, or food, and separating substances with different conductivity and charge.

[0033] [Structure of electrostatic separation device 1]

[0034] like Figure 1As shown, the electrostatic separation apparatus 1 according to this embodiment includes: a container 25 in which a raw material layer 15 is formed; a gas dispersion plate 26 disposed at the bottom of the raw material layer 15; at least one vibrating body V disposed within the raw material layer 15 on the same surface as the gas dispersion plate 26 (or, above the gas dispersion plate 26); a fluidizing gas supply device 29 for supplying fluidizing gas 31 that passes through the gas dispersion plate 26 and causes the raw material layer 15 to rise; an upper electrode 22 disposed above the raw material layer 15; a lower electrode 28 disposed within the raw material layer 15 on the same surface as the gas dispersion plate 26 (or, above the gas dispersion plate 26); a capture device 50; and a power supply device 20.

[0035] The capturing device 50 can be a conveyor-type capturing device. The capturing device 50 consists of an endless conveyor belt 51 and a rotation drive device for the conveyor belt 51 (not shown in the figure). The conveyor belt 51 is made of non-conductor.

[0036] An upper electrode 22 is disposed on the inner side of the loop of the conveyor belt 51. The outer surface of the conveyor belt 51 serves as the conveying surface 52. The area above the raw material layer 15 and below the upper electrode 22 is defined as the "capture area 10". The rotating conveyor belt 51 passes through the capture area 10 with the conveying surface 52 facing downwards. The conveying surface 52 of the conveyor belt 51 passing through the capture area 10 can be approximately horizontal.

[0037] The capturing device 50 includes a particle separation component 43. A conductive particle recovery container 41 is disposed below the particle separation component 43. The particle separation component 43 is, for example, a shovel-shaped component (scraper) that can scrape off particles attached to the conveyor belt 51. However, the particle separation component 43 may also be a component with a de-energizing function (e.g., a de-energizing brush), which separates the particles from the conveyor belt 51 by performing de-energizing of the particles attached to the conveyor belt 51.

[0038] exist Figure 2 The diagram shows a modified example of an electrostatic separation device 1 in which an insulating particle detachment promotion device 53 is provided in the capture device 50. For example... Figure 2 As shown, the capturing device 50 may further include an insulating particle removal promoting device 53 that removes insulating particles 18 that are attached to the conveyor belt 51 or conductive particles 16 due to intermolecular forces from the conveyor belt 51. This allows the insulating particles 18 attached to the conveyor belt 51 due to intermolecular forces to be removed, thereby increasing the concentration of conductive particles 16 recovered by the conductive particle recovery container 41.

[0039] The insulation particle detachment promoting device 53 is, for example, a vibration device configured to impart a rotational vibration generated by the rotation of a motor to the downward transport surface 52 of the conveyer belt 51 by contacting the transport surface 52. However, the insulation particle detachment promoting device 53 can be a vibration device disposed above the transport surface 52 (i.e., the inner side of the ring of the conveyer belt 51) in a manner to contact the surface opposite to the transport surface 52 of the conveyer belt 51. Further, the insulation particle detachment promoting device 53 can also be a device configured to impart a vibration to the conveyer belt 51 by intermittently blowing compressed air. Further, the insulation particle detachment promoting device 53 can also be a device formed of a material that is permeable to a gas but not permeable to the conductive particles 16 and the insulation particles 18, and supplies a small amount of gas from the inner side of the conveyer belt 51 toward the direction of the capturing region 10, thereby detaching the insulation particles 18 adhering to the transport surface 52 or the conductive particles 16.

[0040] Returning to Figure 1 At the bottom of the container 25, a gas dispersion plate 26 having a plurality of minute holes is disposed. The gas dispersion plate 26 can be a porous plate or a porous sheet. By a supply device not shown, the raw material 17 doped with the conductive particles 16 and the insulation particles 18 is supplied to the container 25. The raw material layer 15 is formed from the raw material 17 accumulated in the container 25.

[0041] By continuously or intermittently supplying the raw material 17 to the first side of the container 25, the raw material 17 slowly moves from the first side to the second side opposite thereto of the container 25. At the second side of the container 25, an insulation particle recovery container 40 that recovers the particles (mainly the insulation particles 18) overflowing from the container 25 is provided.

[0042] Figure 3 A plan view showing the relationship between the moving direction Dl of the transport surface 52 of the conveyer belt 51 and the advancing direction D2 of the raw material 17. As shown in Figure 3 , the moving direction Dl of the transport surface 52 of the conveyer belt 51 passing through the capturing region 10, i.e., the moving direction of the conductive particles 16 adhering to the transport surface 52, is substantially orthogonal to the advancing direction D2 of the raw material 17 in the container 25 (the raw material layer 15) in a plan view. In order to process more raw material 17 at a time, the container 25 is preferably enlarged in the width direction D3 orthogonal to the advancing direction D2. In addition, the moving direction Dl and the advancing direction D2 are shown in parallel in Figure 1 , but the relationship between the moving direction Dl and the advancing direction D2 is not limited to these drawings.

[0043] As previously described, the raw material 17 in container 25 moves slowly from the first side of container 25 toward the second side in the travel direction D2. As the raw material 17 in container 25 approaches the capture area 10, the conductive particles 16 become charged and gradually adhere to the conveyor surface 52 of the conveyor belt 51. Therefore, the amount of charged conductive particles 16 gradually decreases from the upstream side to the downstream side of the travel direction D2. On the other hand, the conductive particles 16 attached to the conveyor surface 52 of the conveyor belt 51 adhere to and occupy the conveyor surface 52 until they are removed by the particle separation member 43, thus further hindering the attachment of conductive particles 16. Therefore, when the moving direction D1 is orthogonal to the travel direction D2, the conductive particles 16 can be more effectively attached to and recovered on the conveyor surface 52 compared to the case where the moving direction D1 is parallel to the travel direction D2. If the moving direction D1 of the conveyor surface 52 of the conveyor belt 51 passing through the capture area 10 is parallel to the travel direction D2, the width of the conveyor belt 51 will become wider. From the viewpoint of suppressing the width of the conveyor belt 51, it is preferable that the moving direction D1 and the traveling direction D2 are orthogonal when viewed from above. However, it is also possible for the moving direction D1 and the traveling direction D2 to be parallel.

[0044] Return to Figure 1 A bellows 30 is provided below the container 25. A flowable gas 31 is supplied to the bellows 30 from the flowable gas supply device 29. The flowable gas 31 can be, for example, air. Preferably, the flowable gas 31 is a dehumidified gas (e.g., a dehumidified gas with a dew point below 0°C). The flowable gas 31 is guided by the bellows 30 from the bottom of the container 25 into the raw material layer 15, and while passing through the gas dispersion plate 26, the lower electrode 28, and the intermediate electrode 34, it causes the raw material layer 15 to rise.

[0045] In this embodiment, a metal gas dispersion plate is used as the gas dispersion plate 26, which also functions as the lower electrode 28. However, it is also possible to use... Figure 4 As shown, a lower electrode 28 is provided above the gas dispersion plate 26 within the raw material layer 15. In this case, the lower electrode 28 is composed of a mesh plate that allows the flowable gas 31 to pass through, and the gas dispersion plate 26 can be made of a porous sheet made of resin, metal, or ceramic.

[0046] At least one vibrator V is disposed on the same surface as or above the gas dispersion plate 26 within the raw material layer 15. In this embodiment, the vibrator V is composed of a metal mesh plate disposed within the raw material layer 15 above the gas dispersion plate 26, and the vibrator V also functions as an intermediate electrode 34. However, the intermediate electrode 34 may be omitted, and only the vibrator V may be provided. Alternatively, it may be disposed in a manner similar to... Figure 4In the case where the lower electrode 28 is provided above the gas dispersion plate 26 in the raw material layer 15 as shown, the lower electrode 28 is configured to be vibratable, and the vibration body V functions as the lower electrode 28.

[0047] The mesh plate that forms the intermediate electrode 34 (vibration body V) has meshes that allow the conductive particles 16 and the insulating particles 18 in the raw material layer 15 to pass through. The intermediate electrode 34 is disposed above the lower electrode 28 in the raw material layer 15. The interval between the lower electrode 28 and the intermediate electrode 34 can be several mm to several tens of mm. In the case where a plurality of intermediate electrodes 34 are provided, the plurality of intermediate electrodes 34 are arranged in the vertical direction, and the plurality of intermediate electrodes 34 and the lower electrode 28 are disposed to be substantially parallel to the bottom surface of the container 25.

[0048] In the case where a plurality of intermediate electrodes 34 are provided, the meshes of the plurality of intermediate electrodes 34 can be the same. Alternatively, in the case where a plurality of intermediate electrodes 34 are provided, the intermediate electrodes 34 disposed higher can have larger meshes. For example, in the case where the plurality of intermediate electrodes 34 include a first intermediate electrode 34a and a second intermediate electrode 34b arranged vertically, the first intermediate electrode 34a disposed higher has larger meshes than the second intermediate electrode 34b.

[0049] The power supply device 20 applies a voltage between the upper electrode 22 and the lower electrode 28 that face each other in the vertical direction, so that an electric field is generated between the two electrodes with one of the upper electrode 22 and the lower electrode 28 being a negative (-) electrode and the other being a positive (+) electrode. In the present embodiment, the power supply device 20 applies a negative voltage to the upper electrode 22 and grounds the lower electrode 28, so that the upper electrode 22 becomes a negative electrode and the lower electrode 28 becomes a positive electrode. As an example, in the case where the interval between the upper electrode 22 and the lower electrode 28 is several tens of mm to several hundreds of mm, the strength of the electric field generated between the upper electrode 22 and the lower electrode 28 can be 0.1 to 1.5 kV / mm in absolute value.

[0050] Further, the power supply device 20 applies a voltage between the upper electrode 22 and the intermediate electrode 34, so that the intermediate electrode 34 becomes the same polarity as the lower electrode 28 among the negative electrode and the positive electrode. The potential difference between the upper electrode 22 and the intermediate electrode 34 can be lower than the potential difference between the upper electrode 22 and the lower electrode 28.

[0051] For example, as shown in FIG. 6, the power supply device 20 can apply a voltage between the upper electrode 22 and the intermediate electrode 34, so that the intermediate electrode 34 becomes the same polarity as the lower electrode 28 among the negative electrode and the positive electrode. Figure 5The plurality of intermediate electrodes 34 and the lower electrode 28 are grounded as shown, and a negative voltage is applied to the upper electrode 22. In this case, the plurality of intermediate electrodes 34 and the lower electrode 28 become positive electrodes, the upper electrode 22 becomes a negative electrode, and the lower electrode 28 and the plurality of intermediate electrodes 34 become equipotential. In this case, there is no potential difference between the intermediate electrodes 34 and between the intermediate electrodes 34 and the lower electrode 28. However, because the intermediate electrodes 34 are meshed plates, an electric field is generated between the electrodes of the lower electrode 28 and the upper electrode 22 in a manner that the potential difference between the lower electrode 28 and the upper electrode 22 passes through the meshes of the intermediate electrodes 34, and thus it can be considered that an electric field is also generated between the lower electrode 28 and the intermediate electrodes 34 and between the intermediate electrodes 34.

[0052] Further, for example, the lower electrode 28 can be grounded as shown, and a negative voltage can be applied to the intermediate electrodes 34 and the upper electrode 22. Figure 6 In the case where the plurality of intermediate electrodes 34 include the first intermediate electrode 34a and the second intermediate electrode 34b arranged one above the other, the upper electrode 22 can be set to -20 kV, the first intermediate electrode 34a and the second intermediate electrode 34b can be set to -2 kV, and the lower electrode 28 can be set to 0 kV (the values are merely examples). In this case, the plurality of intermediate electrodes 34 and the lower electrode 28 become positive electrodes, the upper electrode 22 becomes a negative electrode, and the plurality of intermediate electrodes 34a, 34b become equipotential. Although a potential difference is generated between the intermediate electrodes 34a, 34b and the lower electrode 28, the potential difference between the upper electrode 22 and the intermediate electrodes 34a, 34b and the potential difference between the upper electrode 22 and the lower electrode 28 are sufficiently small. In such a relationship, the electric field strength between the lower electrode 28 and the intermediate electrode 34 arranged at the lowermost position (the second intermediate electrode 34b in the present embodiment) can be increased compared to the case shown in FIG. 8. Figure 5

[0053] Further, in the case where the plurality of intermediate electrodes 34 include the first intermediate electrode 34a and the second intermediate electrode 34b arranged one above the other, the upper electrode 22 can be set to -20 kV, the first intermediate electrode 34a can be set to -4 kV, the second intermediate electrode 34b can be set to -2 kV, and the lower electrode 28 can be set to 0 kV (the values are merely examples). That is, the potential difference between the upper electrode 22 and each of the intermediate electrodes 34 can be set in a manner that the potential difference between the upper electrode 22 and the intermediate electrodes 34 decreases as it moves away from the lower electrode 28 (in other words, in a manner that the potential difference with the lower electrode 28 increases). In this case, the electric field strength between the intermediate electrodes 34 can be higher than in the case shown in FIG. 9, except for the electric field strength between the lower electrode 28 and the intermediate electrode 34 arranged at the lowermost position (the second intermediate electrode 34b in the present embodiment). Figure 5 ​​

[0054] Figure 7 This figure illustrates a modified example of the electrostatic separation device 1 equipped with a vibrating excitation device 33. (See figure for details.) Figure 7 As shown, the electrostatic separation device 1 may also include a vibratory excitation device 33 that causes at least one of the vibratory bodies V (which can function as an intermediate electrode 34) to vibrate independently of the container 25. Figure 7 In the example shown, container 25 is fixed, and vibrator V vibrates relative to container 25. Vibrator excitation device 33 is a device that causes at least one vibrator V to vibrate in one or more of the vertical and horizontal directions. The vibration can be reciprocating or circular motion. Furthermore, multiple vibrator excitation devices 33 with different frequencies can be provided, and the vibrations of different frequencies can overlap by having the vibrator V move with small amplitudes while simultaneously moving with large amplitudes.

[0055] Figure 8 This figure illustrates a modified example of the electrostatic separation device 1, which includes a vibrating excitation device 33 and a container vibration device 32. (See figure for details.) Figure 8 As shown, the electrostatic separation device 1 may include a container vibration device 32 in addition to the vibrating body excitation device 33 described above. The container vibration device 32 is a device that vibrates the container 25 in one or more directions, including the vertical and horizontal directions. The vibration can be reciprocating or circular. By including such independent container vibration device 32 and vibrating body excitation device 33, the lower electrode 28 and at least one intermediate electrode 34 can vibrate independently. For example, the lower electrode 28 and the intermediate electrode 34 can vibrate at different frequencies, or in different directions.

[0056] [Electrostatic Separation Method]

[0057] The electrostatic separation method of the electrostatic separation device 1 using the above structure will be described here.

[0058] exist Figure 1 In the electrostatic separation device 1 shown, the electric field generated between the upper electrode 22 and the lower electrode 28 causes dielectric polarization of the conveyor belt 51, which is a non-conductor (insulator / dielectric), and generates negative or positive (corresponding to the upper electrode 22) charges on the downward conveying surface 52 that passes through the capture area 10 within the conveyor belt 51. In this embodiment, the upper electrode 22 is a negative electrode, thus generating negative charges on the conveying surface 52.

[0059] The raw material layer 15 in the container 25 is fluidized by the fluidizing gas 31, and a flow of the raw material 17 in the up-and-down direction and the left-and-right direction is generated in the raw material layer 15. That is, the raw material layer 15 is stirred. By this stirring, the electrically conductive particles 16 that are in contact with the lower electrode 28 and / or the intermediate electrode 34 are charged positively or negatively (in correspondence with the lower electrode 28). In the present embodiment, the lower electrode 28 is a positive electrode, and thus the electrically conductive particles 16 are charged positively. The insulating particles 18 (non-conductor) can also be charged by being in contact with the lower electrode 28.

[0060] The charged electrically conductive particles 16 move to the surface layer portion of the raw material layer 15 by the flow of the raw material 17, and are attracted by the electrostatic force to the downward transport surface 52 of the conveyer belt 51, fly out from the raw material layer 15, and adhere to the downward transport surface 52. Since the electrically conductive particles 16 do not directly contact the upper electrode 22, the charged state can be maintained, and the state of being attracted to the downward transport surface 52 of the conveyer belt 51 can be continued.

[0061] The electrically conductive particles 16 that have adhered to the transport surface 52 of the conveyer belt 51 as described above are carried outside the electric field by the rotation of the conveyer belt 51. Then, the electrically conductive particles 16 are peeled from the transport surface 52 of the conveyer belt 51 outside the electric field by the particle separation member 43, and are recovered by the electrically conductive particle recovery container 41.

[0062] On the other hand, since the insulating particles 18 in the raw material layer 15 are not charged, they are not electrostatically attracted to the downward transport surface 52 of the conveyer belt 51, and remain in the raw material layer 15. The raw material 17 that is fed into the container 25 has a decreasing proportion of electrically conductive particles 16 and an increasing proportion of insulating particles 18 as the container 25 moves from the first side toward the second side. In the insulating particle recovery container 40 that is disposed at the second side of the container 25, the raw material 17 that has a high proportion of insulating particles 18 that have overflowed from the container 25 is recovered.

[0063] [Summary of the Present Embodiment]

[0064] As described above, the electrostatic separation device 1 according to the above-described embodiment is an electrostatic separation device 1 that separates electrically conductive particles 16 from a raw material 17 in which the electrically conductive particles 16 and insulating particles 18 are mixed,

[0065] The electrostatic separation device 1 includes:

[0066] a container 25 in which a raw material layer 15 made of the raw material 17 is formed;

[0067] a gas dispersion plate 26 disposed at the bottom of the raw material layer 15;

[0068] at least one vibration body V disposed in the raw material layer 15 on the same plane as or above the gas dispersion plate 26;

[0069] a fluidizing gas supply device 29 that supplies a fluidizing gas 31 directed into the raw material layer 15 from the bottom of the container 25 and passing through the gas dispersion plate 26 to raise the raw material layer 15;

[0070] an upper electrode 22 disposed above the raw material layer 15;

[0071] a lower electrode 28 disposed in the raw material layer 15 on the same plane as or above the gas dispersion plate 26;

[0072] a power supply device 20 that applies a voltage between the upper electrode 22 and the lower electrode 28 in a manner that one of the upper electrode 22 and the lower electrode 28 is set as a negative electrode and the other is set as a positive electrode, and an electric field is generated between the electrodes;

[0073] a capturing device 50 that captures the conductive particles 16 flying from the surface of the raw material layer 15 toward the upper electrode 22.

[0074] In the above embodiment, at least one of the vibration bodies V can be configured to vibrate independently with respect to the container 25.

[0075] Since the raw material 17 constituting the raw material layer 15 has a smaller particle size than a fluid medium (e.g., sand) forming a general fluid layer, it is easy to generate a blow of the fluidizing gas 31, and when a blow is generated, the raw material layer 15 does not fluidize well. Therefore, by providing the vibration body V in the raw material layer 15 as described above, it is possible to suppress the generation of a blow in the raw material layer 15, and further, it is possible to maintain a good fluid state of the raw material layer 15. As a result, it is possible to promote the contact of the electrodes with the raw material 17, and thus it is possible to achieve an improvement in the processing capacity of the electrostatic separation device 1.

[0076] Especially in the case where the container 25 is fixed and only the vibration body V is vibrated by the vibration body excitation device 33, compared to the case where the container 25 is vibrated, it is possible to achieve miniaturization and cost reduction of the vibration body excitation device 33 due to the lightweight and miniaturization of the vibration object. Therefore, in order to improve the processing capacity of the electrostatic separation device 1, it is easy to increase the size of the container 25.

[0077] Further, the electrostatic separation device 1 according to the above embodiment has at least one intermediate electrode 34 disposed in the raw material layer 15 above the lower electrode 28.

[0078] In the electrostatic separation device 1 described above, the potential difference between the upper electrode 22 and the intermediate electrode 34 is lower than the potential difference between the upper electrode 22 and the lower electrode 28. For example, the intermediate electrode 34 and the lower electrode 28 can be at the same potential. Alternatively, in the case where a plurality of intermediate electrodes 34 are provided, the voltage can be applied between the upper electrode 22 and each of the intermediate electrodes 34 in such a manner that the greater the distance between the intermediate electrode 34 and the lower electrode 28, the smaller the potential difference between the upper electrode 22 and the intermediate electrode 34.

[0079] According to the electrostatic separation device 1 configured as described above, the intermediate electrode 34 is arranged in the flowing raw material layer 15, and the conductive particles 16 in the raw material layer 15 are charged not only by contact with the lower electrode 28 but also by contact with the intermediate electrode 34. Thus, compared with the case where the intermediate electrode 34 is not provided, the charging opportunities of the conductive particles 16 increase, and the charging of the conductive particles 16 can be promoted.

[0080] Further, in the electrostatic separation device 1 configured as described above, since the intermediate electrode 34 is arranged above the lower electrode 28, the conductive particles 16 can be charged also at a position in the raw material layer 15 that is away upward from the lower electrode 28. Thus, the amount of the raw material 17 that has a thickness and stays in the container 25 can be increased, and the processing capacity of the electrostatic separation device 1 can be improved. Further, the conductive particles 16 that are charged by contact with the intermediate electrode 34 have a shorter time (rising distance) to move to the surface layer portion of the raw material layer 15 after being charged than the conductive particles 16 that are charged by contact with the lower electrode 28. Thus, the separation efficiency of the conductive particles 16 increases, and the processing time can be shortened.

[0081] As described in the above embodiment, the intermediate electrode 34 can be configured to be vibratable, and the intermediate electrode 34 can function as the vibration body V.

[0082] Further, as described in the above embodiment, the lower electrode 28 can be configured to be vibratable, and the lower electrode 28 can function as the vibration body V.

[0083] Thus, by vibrating the intermediate electrode 34 and the lower electrode 28, the opportunities of the conductive particles 16 in the raw material layer 15 to contact with the intermediate electrode 34 and the lower electrode 28 increase, and further charging promotion of the conductive particles 16 can be expected.

[0084] Further, as described in the above embodiment, in the electrostatic separation device 1 described above, the intermediate electrode 34 can include a first intermediate electrode 34a and a second intermediate electrode 34b arranged in the vertical direction, and the mesh of the first intermediate electrode 34a can be larger than the mesh of the second intermediate electrode 34b.

[0085] The intermediate electrodes 34 promote charging of the conductive particles 16 and hinder the upward movement of the conductive particles 16. Therefore, the mesh of the first intermediate electrode 34a arranged on the upper side is larger than the mesh of the second intermediate electrode 34b arranged on the lower side, so that the degree of hindrance of the movement of the conductive particles 16 is reduced as the conductive particles 16 move upward within the raw material layer 15. Thus, it is expected that the effect of maintaining the good fluidization of the raw material layer 15 is obtained.

[0086] Further, in the electrostatic separation device 1 according to the above embodiment, the capturing device 50 has a conveyor belt 51 composed of a non-conductor, which is arranged so that the upper side of the raw material layer 15 and the lower side of the upper electrode 22 are included in a capturing region 10 and the conveyor belt 51 rotates so that a conveying surface 52 faces the capturing region 10 downward.

[0087] In the electrostatic separation device 1 having the above structure, the conductive particles 16 are selectively detached from the raw material layer 15 by the electrostatic force and attached to the conveying surface 52 of the conveyor belt 51. Thus, the amount of the insulating particles 18 attached to the conveying surface 52 of the conveyor belt 51 can be reduced. As a result, the insulating particles 18 can be reduced in the powder particles composed mainly of the conductive particles 16 collected by the conductive particle collection container 41.

[0088] Further, in the electrostatic separation device 1 according to the above embodiment, the capturing device 50 further has an insulating particle detachment promoting device 53 that detaches the insulating particles 18 attached to the conveyor belt 51 or the conductive particles 16 by intermolecular forces from the conveyor belt 51.

[0089] It is assumed that the conductive particles 16 and the insulating particles 18 are adsorbed together by intermolecular forces, the insulating particles 18 fly out of the raw material layer 15 together with the conductive particles 16, and the insulating particles 18 are attached to the conveyor belt 51 (or the conductive particles 16). The insulating particles 18 thus attached to the conveyor belt 51 are detached from the conveyor belt 51 by the action of the insulating particle detachment promoting device 53 and returned to the raw material layer 15 or collected by the insulating particle collection container 40. Thus, the insulating particles 18 can be reduced in the conductive particles 16 collected by the conductive particle collection container 41. As a result, the purity of the conductive particles 16 collected by the conductive particle collection container 41 can be improved.

[0090] Further, in the electrostatic separation device 1 according to the above embodiment, the capturing device 50 further has a particle separation member 43 that separates the conductive particles 16 attached to the conveyor belt 51 by the electrostatic force from the conveyor belt 51 by de-electrifying the conductive particles 16.

[0091] Thus, the conductive particles 16 adhering to the conveyance belt 51 can be easily removed from the conveyance belt 51, and the charging of the conductive particles 16 can be removed, so that an electric discharge treatment after the recovery is not required.

[0092] Further, in the electrostatic separation device 1 according to the above embodiment, the moving direction D1 of the conveyance surface 52 in the capturing region 10 realized by the rotation of the conveyance belt 51 and the advancing direction D2 of the raw material 17 in the container 25 are orthogonal in a plan view.

[0093] Likewise, in the electrostatic separation method according to the present embodiment, the moving direction D1 of the conveyance surface 52 in the capturing region 10 realized by the rotation of the conveyance belt 51 and the advancing direction D2 of the raw material 17 in the raw material layer 15 are orthogonal in a plan view.

[0094] Thus, the moving direction D1 of the conveyance surface 52 in the capturing region 10 and the advancing direction D2 of the raw material 17 are orthogonal, so that the conductive particles 16 can be more effectively adhered to the conveyance surface 52 than when these directions are parallel.

[0095] The above describes the preferred embodiments of the present application (and modifications), but the detailed contents of the specific structure and / or functions of the above embodiments are changed within the scope of the idea of the present application, and are included in the present application. The above structure can be changed, for example, as follows.

[0096] For example, in the above embodiment, the lower electrode 28 is provided as a positive electrode and the upper electrode 22 is provided as a negative electrode, but the lower electrode 28 can be provided as a negative electrode and the upper electrode 22 can be provided as a positive electrode according to the properties of the conductive particles 16.

[0097] For example, in the above embodiment, the conveyance type capturing device using electrostatic force is used as the capturing device 50, but the type of the capturing device 50 is not limited to this. For example, the capturing device 50 can be configured to perform air flow conveyance and recovery of the conductive particles 16 flying from the surface layer of the raw material layer 15.

[0098] Explanation of Reference Numerals

[0099] 1: electrostatic separation device;

[0100] 10: capturing region;

[0101] 15: raw material layer;

[0102] 16: conductive particle;

[0103] 17: raw material;

[0104] 18: insulating particle;

[0105] 20: power supply device;

[0106] 22: upper electrode;

[0107] 25: container;

[0108] 26: gas dispersing member;

[0109] 28: lower electrode;

[0110] 29: fluidizing gas supply device;

[0111] 31: fluidizing gas;

[0112] 32: container vibration device;

[0113] 33: vibration body excitation device;

[0114] 34: intermediate electrode;

[0115] 34a: first intermediate electrode;

[0116] 34b: second intermediate electrode;

[0117] 43: particle separating member;

[0118] 50: capturing device;

[0119] 51: conveyer belt;

[0120] 52: conveying surface;

[0121] 53: insulating particle detachment promoting device;

[0122] V: vibration body.

Claims

1. An electrostatic separation device that separates conductive particles from a raw material containing the conductive particles and insulating particles, the electrostatic separation device comprising: a container in which a raw material layer composed of the raw material is formed; a gas dispersion plate disposed at a bottom of the raw material layer; at least one vibration body disposed in the raw material layer at a same surface as or above the gas dispersion plate; a fluidizing gas supply device that supplies fluidizing gas directed from a bottom of the container into the raw material layer and passing through the gas dispersion plate to lift the raw material layer; an upper electrode disposed above the raw material layer; a lower electrode disposed in the raw material layer at a same surface as or above the gas dispersion plate; at least one intermediate electrode disposed in the raw material layer above the lower electrode; a power supply device that applies a voltage between the upper electrode and the lower electrode with one of the upper electrode and the lower electrode serving as a negative electrode and the other serving as a positive electrode and generates an electric field between the electrodes, and applies a voltage between the upper electrode and the intermediate electrode to make a potential difference between the upper electrode and the intermediate electrode smaller than a potential difference between the upper electrode and the lower electrode; a capturing device that captures the conductive particles flying from a surface of the raw material layer toward the upper electrode; and a vibration body excitation device that independently vibrates the intermediate electrode with respect to the container.

2. The electrostatic separation device according to claim 1, further comprising a container vibration device that independently vibrates the container with respect to the intermediate electrode.

3. The electrostatic separation device according to claim 1 or 2, wherein the lower electrode is configured to be vibratable, and the lower electrode functions as the vibration body.

4. The electrostatic separation device according to claim 1, comprising a plurality of the intermediate electrodes arranged in a vertical direction, and the voltage is applied between the upper electrode and the intermediate electrodes to make a potential difference from the upper electrode smaller as it is farther from the lower electrode.

5. The electrostatic separation device according to claim 1, wherein the intermediate electrode includes a first intermediate electrode and a second intermediate electrode arranged in a vertical direction, and a mesh of the first intermediate electrode is larger than a mesh of the second intermediate electrode.

6. The electrostatic separation device according to claim 1, wherein the capturing device includes a conveyor belt that rotates with a conveying surface thereof passing through a capturing area above the raw material layer and below the upper electrode.

7. The electrostatic separation device according to claim 6, wherein the capturing device further includes an insulating particle detachment promoting device that detaches the insulating particles adhering to the conveyor belt or the conductive particles due to intermolecular forces from the conveyor belt. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. The electrostatic separation device according to claim 6 or 7, wherein the capturing device further has a particle separation section that separates the conductive particles from the conveyor belt by de-electrifying the conductive particles attached to the conveyor belt by the electrostatic force.

9. The electrostatic separation device according to claim 6 or 7, wherein the moving direction of the conveying surface in the capturing region realized by the revolution of the conveyor belt is orthogonal to the advancing direction of the raw material within the container in a plan view.

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