JP2003103198A - Electrostatic separator of plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To feed plastic pieces to an electrostatic separator via a triboelectrifying device without being accompanied with dust while using a dry cleaning device of a low cost. SOLUTION: The electrostatic separator of plastic is provided with the dry cleaning device the triboelectrifying device and an electrostatically separating equipment for classifying the plastic pieces and further a dust removing device 2 is provided between the dry cleaning device and the triboelectrifying device. The dust removing device 2 is provided with a mesh plate 36 for supporting the plastic piece from below, a mesh plate vibrating device 37 for vibrating the mesh plate 36, a dust sucking device 38 for sucking and removing the dust accompanying the plastic pieces via the mesh plate and a static eliminator 39.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic electrostatic separation facility for crushing recycled plastic into plastic pieces, separating the plastic pieces according to type, and reusing them.

[0002]

2. Description of the Related Art Conventionally, as a separator for separating collected plastic pieces by crushing them into a predetermined size, washing and drying them, and separating these plastic pieces by friction, they are charged by friction. , By passing the electrostatic field formed between the electrodes, the falling trajectory of the plastic piece is changed in accordance with the polarity and the amount of charge that are charged according to the charging sequence and are different for each type of plastic piece,
An electrostatic separation type has been proposed which separates plastic pieces by type.

In the above-mentioned plastic electrostatic separation equipment,
If foods such as edible oils and fats, salt, etc. adhere to the surface of the crushed plastic pieces, the separation performance will deteriorate, so the plastic pieces are washed, but in wet washing, a large amount of line water is used. In addition, since it is necessary to dry the plastic piece in a later step, there is a problem that equipment cost and running cost increase. Therefore, a dry cleaning apparatus has been proposed which cleans the surface of a plastic piece by rubbing the plastic pieces together.

[0004]

However, in the above-mentioned dry cleaning device, polluted dust separated from the surface of the plastic piece or scraped off plastic dust is generated, and the dust is entrained in the plastic piece to cause the frictional charging device. When it is supplied to the electrostatic separation device, there is a problem that the charging characteristics of the plastic piece change and the accuracy of the electrostatic separation deteriorates.

The present invention solves the above-mentioned problems, and while using a low-cost dry cleaning device, plastic pieces can be supplied to the friction charging device without entraining dust, and the electrostatic separation device can be used with high precision. Another object of the present invention is to provide a plastic electrostatic separation equipment capable of separately separating plastic pieces.

[0006]

In order to achieve the above object, the invention according to claim 1 provides a dry cleaning apparatus for contacting a plastic piece to remove contaminants adhering to the surface, and a plastic piece after cleaning. A plastic provided with a frictional charging device that makes frictional contact and charges, and an electrostatic separation device that supplies a charged plastic piece to an electrostatic field formed between electrodes to change the falling trajectory and separate the plastic piece by type. In the electrostatic separation equipment, a dust removing device is provided between the dry cleaning device and the frictional charging device, and the dust removing device includes a mesh plate that supports a plastic piece from below, and a vibrating means that vibrates the mesh plate. And dust suction means for sucking and removing the dust entrained in the plastic pieces through the mesh plate.

According to the above construction, the plastic piece discharged from the dry dust collector is put on the mesh plate, the vibrating means vibrates and agitates the plastic piece through the mesh plate, and the dust collecting means sucks dust. By doing so, the dust separated from the surface can be effectively removed from the plastic piece. While using a low-cost dry cleaning device that does not require drying, the dust generated by cleaning can be effectively removed from the plastic pieces and supplied to the triboelectrification device and electrostatic separation device. The plastic pieces can be separated by type with high accuracy without lowering the separation accuracy.

According to a second aspect of the present invention, in the structure according to the first aspect, a static eliminating means for neutralizing the electric charge of the plastic piece is arranged above the mesh plate of the dust removing device. According to the above configuration, the static eliminating means neutralizes the electric charge generated by the rubbing of the plastic pieces to remove static electricity, thereby preventing the plastic pieces from adhering to each other or the plastic pieces and dust from adhering to each other. Dust can be effectively removed.

According to a third aspect of the present invention, a dry cleaning device for contacting a plastic piece to remove contaminants adhering to the surface thereof, a frictional charging device for frictionally contacting the cleaned plastic piece to charge the surface, and a charged electrification device. In a plastic electrostatic separation equipment equipped with an electrostatic separation device that supplies a plastic piece to an electrostatic field formed between electrodes to change the falling trajectory and separates the plastic piece according to type, it is incorporated in the dry cleaning device. Or a pre-stage dust removing device arranged on the outlet side of the dry cleaning device, a pre-stage dust removing device incorporated into the dry cleaning device or arranged on the outlet side of the dry cleaning device, the pre-stage dust removing device and the above-mentioned A rear-stage dust removing device is provided between the friction charging devices, and the front-stage dust removing means has a mesh plate that supports the plastic piece from below,
A dust suction means for sucking and removing dust entrained in the plastic piece through the mesh plate is provided, and a mesh plate for supporting the plastic piece from below in the latter-stage dust removing device, and a vibrating means for vibrating the mesh plate. A dust suction means for sucking and removing dust entrained in the plastic piece through the mesh plate, and a destaticizing means arranged above the mesh plate for neutralizing the electric charge of the plastic piece are provided.

According to the above construction, the coarse dust having a large diameter is sucked and removed from the plastic piece by the mesh plate and the dust suction means of the pre-stage dust remover, and then the plastic piece is vibrated on the mesh plate by the post-stage dust remover. At the same time, the charge of the plastic piece is neutralized by the static elimination means, so that the plastic piece and the dust can be separated and the fine dust with a small diameter can be effectively sucked and removed by the suction means. As a result, contaminants on the separated surface can be removed to the extent that the separation accuracy such as purity and recovery rate does not decrease. Therefore, while using a low-cost dry cleaning device that does not require drying, dust generated by cleaning can be effectively removed from the plastic pieces and supplied to the friction charging device and the electrostatic separation device. It is possible to separate plastic pieces by type with high accuracy without lowering the separation accuracy.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Here, an embodiment of a plastic electrostatic separation facility according to the present invention will be described with reference to FIGS.

In this plastic sorting facility, plastic bottles collected for recycling are pretreated and crushed to a predetermined size, and plastic pieces sieved to a predetermined size by a sieving device are separated by type. Things
As shown in FIG. 1, a dry cleaning device 1, a dust separating device (post-stage dust removing device) 2, a triboelectric charging device 3, in order from the upstream side.
A fixed quantity supply device 4 and an electrostatic separation device 5 are arranged.

The dry cleaning device 1 removes crystals of oils and fats, sugar, salt, etc. adhering to the surface of the plastic pieces by frictionally contacting the plastic pieces with each other and the plastic pieces with the casing 11 and the stirring member.

That is, a rotating shaft 12 having a conveying screw (stirring member) 13 and a plurality of stirrer rods (stirring member) 14 protruding in the radial direction is provided at the axial center of the horizontally-arranged cylindrical cleaning casing 11. The rotating shaft 12 is rotatably arranged and is driven to rotate in a predetermined direction at a predetermined speed by a stirring motor 15 provided at one end of the casing 11. The inlet formed on one end side of the casing 11 has
A pressurizing device (not shown) such as a spring, a weight, a fluid pressure cylinder, etc., to which a supply hopper 16 is attached and an outlet 17 opened at the other end of the casing 11 is capable of adjusting the pressure applied to the closing side. The pressure gate 18 having the above is arranged, and the pressure for rubbing the plastic pieces in the casing 11 can be adjusted by the pressure gate 18.

The dry cleaning apparatus 1 is also provided with a dust suction unit (previous stage dust removing apparatus) 20 for removing dust generated when cleaning the plastic pieces. The dust suction part 20 is a part of the casing 11 corresponding to the mounting part of the stirring rod 14, for example, a mesh plate 21 of a predetermined roughness that is attached to a notch on the lower surface and supports a plastic piece from below, The mesh plate 21 is provided with a dust collecting cover 22 forming a dust collecting space, and a dust collecting duct 23 connected to the dust collecting cover 22. The dust collecting duct 23 is provided with a dust separating cyclone 24 through a filter. It is connected to the air supply port of the attached pre-stage dust suction fan 25.

Therefore, in the dry cleaning device 11, the plastic pieces or the plastic pieces are pressed against the inner surface of the stirring rod 13 and the casing 11 and rubbed against each other, and the contaminants on the surface and the plastic surface are peeled off and cleaned. As a result, dust is generated, but the dust suction unit 20 mainly removes coarse dust of about 100 μm or more from the mesh plate 21 through the dust collection duct 23 to the pre-stage dust suction fan 25.

As shown in FIG. 2, the dust removing device 2 has an inlet 32 on one end side of a dust collecting case 31 having a horizontally-disposed rectangular tubular cross section.
Is connected to the intermediate duct 33 connected to the outlet 17 of the dry cleaning device 1, and the outlet duct 34 connected to the friction charging device 3 is connected to the other end outlet 34. In the dust collection case 31, a mesh plate 36 for supporting the plastic piece from below, a mesh vibrating device (vibrating means) 37 for vibrating the mesh plate 36, and a plastic piece accompanied with the plastic piece within a range that does not hinder the vibration of the plastic piece. Second-stage dust suction device (dust suction device) 38 that sucks the dust that has passed through the mesh plate 36, and a static eliminator device (static elimination device) 39 that is disposed above the mesh plate 35 to neutralize the electric charge of the plastic piece.
And are provided.

That is, in the dust collection case 31, the inlet 3
2 A diaphragm 41 is arranged horizontally or slightly inclined downward on the outlet side via a mesh vibrating device 37 from below to the outlet 34 so that the diaphragm 41 can vibrate.
2 and the mesh plate 35, which is attached to the inside of the frame member 42 and is made of a wire mesh of about 10 mesh (sieve opening 1.651 mm). The mesh vibrating device 37 vibrates the vibrating plate 41 from the lower side of the inlet to the upper side of the outlet at a predetermined amplitude cycle to separate dust from the plastic pieces on the vibrating plate 41 and convey the plastic pieces from the inlet 32 to the outlet 34. Then, a plurality of guide links (or leaf springs) 44 and a restraining spring 45 are provided on the support member 40.
The vibrating plate 41 is swingably supported via the oscillating plate 41, and is connected to the lower end portion of the drive link 46 connecting the supporting member 40 and the vibrating plate 41 by the vibrating motor 43 via the eccentric cam. .

The dust collecting device 37 includes the mesh plate 35.
And a funnel-shaped dust guide plate 47 that covers the lower surface of the diaphragm 41 in the dust suction case 31, and the dust suction duct 48 that is connected to an exhaust port formed in the center of the dust guide plate 47. The duct 48 is connected to a supply port of a post-stage dust suction fan 50 with a filter via a cyclone 49 for separating fine dust.

The static eliminator 38 has a plurality of needle-shaped corona electrodes 51 projecting downward from the ceiling plate 52 of the dust collection case 31, and a high voltage is applied to the corona electrodes 51 from a high voltage power source to generate ions. It is possible to neutralize the electric charges (static electricity) of the plastic pieces and dust charged by frictional contact by generating and pouring these ions into the plastic pieces. Therefore, by neutralizing the plastic pieces that tend to adhere to each other due to static electricity or the dust that adheres to the plastic pieces, particularly fine dust of 100 μm or less is effectively separated, and the dust that accompanies the plastic pieces is effectively attached. Can be removed.

The frictional charging device 4 stirs and mixes plastic pieces and rubs them against each other to frictionally charge them.
A charging shaft for charging a plastic piece to its type of polarity and charging amount according to a charging column, and a rotating shaft having a plurality of radial stirring blades 62 in a standing cylindrical charging casing 61 having an inlet 60 at the top. 63 is rotatably arranged in the axial center part, and the stirring blade body 62 is rotationally driven by the reduction motor-equipped charging motor 64 via the rotation shaft 63, so that plastic pieces or plastic pieces and the charging casing 61, stirring blade It is brought into frictional contact with the body 62 to be charged to a polarity and a charge amount according to the type of plastic piece, and is supplied from the lower discharge port 66 to the constant amount supply device 4 via a gate device 65 whose opening can be adjusted.

The fixed quantity supply device 4 is composed of a vibrating chute plate 67 and a chute plate vibrating device 68, and supplies a fixed amount of charged plastic pieces in a uniform thickness (a laminated state).

The electrostatic separation device 5 is rotatably supported around a horizontal axis, and a plastic piece is supplied to the top from the constant amount supply device 4, and is driven to rotate at a predetermined speed in the arrow direction by a driving device (not shown). An electrically conductive drum electrode 71,
A conductive counter electrode 72, which is arranged at a predetermined distance diagonally above the front of the drum electrode 71 in the rotation direction, and an anode is grounded and a cathode is connected to the counter electrode 72,
A high-voltage power supply device 74 that forms an electrostatic field 73 between the grounded drum electrode 71 and the counter electrode 72, and the drum electrode 7 below the electrostatic field 73 by the separators 75a and 75b.
The first to third sorting trays 75A to 75C, which are separated into the first side, the portion immediately below the electrostatic field 73, and the counter electrode 72 side, and the plastic piece attached to the drum electrode 71 above the end of the first tray 75A are scratched. And a rotating brush 76 for dropping.

Therefore, the plastic piece introduced from the constant quantity supply device 4 into the vicinity of the top of the drum electrode 71 adheres to the surface of the drum electrode 71 by the image force, and further the centrifugal force acts on the plastic piece as the drum electrode 71 rotates. Gravity is added, and when the electrostatic field 73 is entered, an electrostatic force acts on the plastic piece. In the electrostatic field 73, an electrostatic force that repels the drum electrode 71 acts on the plastic piece charged with the same polarity (for example, +) as the drum electrode 71, and the image force> electrostatic force + centrifugal force is applied to the counter electrode 72. It draws an approaching track and is dropped and collected in the third separation tray 75C. Further, the electrostatic force attracted by the drum electrode 71 acts on the plastic piece charged to the opposite polarity (-) to the drum electrode 71, and the image force + electrostatic force> centrifugal force, and the drum electrode 71
Is drawn onto the first separation tray 75A and drawn and collected so as to be collected by the first separation tray 75A. The plastic pieces that are insufficiently charged are dropped and collected on the second tray 75B.

In the above structure, the dry cleaning device 1 rubs the plastic pieces together to scrape off the contaminants adhering to the surface, and the dust suction part 20 mainly sucks and removes large dust from the mesh plate 21.

Then, the dust separator 2 is separated from the intermediate duct 33.
When the plastic piece is sent to, the plastic piece is conveyed while being unraveled by the vibration of the diaphragm 41, and the electric charges are neutralized by the ions falling from the corona electrode 51 of the static eliminator 39 to remove the static electricity. The dust released from adsorption to the plastic piece due to static electricity is sucked and discharged along with the air sucked into the dust suction duct 48 through the mesh plate 21. As a result, even dust with a small diameter can be removed very effectively from the plastic pieces.

The plastic pieces from which the dust has been removed by the dust separating device 2 are supplied to the frictional charging device 3 and rubbed against each other, and are charged to have a polarity and a charge amount according to the type of the plastic pieces according to the charging sequence. Then, it is supplied from the constant quantity supply device 4 to the electrostatic separation device 5, and the electrostatic field 73 formed by the drum electrode 71 and the counter electrode 72 changes the falling trajectory according to the polarity and charge amount of the plastic piece, 1
~ Separate songs are collected in the third separating trays 75A to 75C. Note that the plastic pieces collected in the intermediate second separation tray 85B are returned to the frictional charging device 3 again after being discharged, and separated.

Here, the results of an experiment in which salt is attached to a plastic piece made of ABS resin and the dust separating device 2 is used will be described. After immersing the plastic piece in an aqueous solution of NaCl, take out the plastic piece, dry it, and dry-clean it using a dry-cleaning device that does not have a dust suction part. The sample 2 from which is removed and the sample 3 from which the dust separating device 2 having the above-mentioned configuration is used for a predetermined period of time to remove dust are respectively introduced into distilled water to dissolve salt, and adhered to the samples 1 to 3, respectively. Table 1 shows the measured salinity. The measurement of the amount of salt at this time is
The electrodes were dipped in a dissolved and dissolved aqueous solution to be energized, and the electric conductivity was determined from the energized current value to calculate the salt content.

[0029]

[Table 1] According to the above-mentioned experiment, the salt content of the plastic pieces on which NaCl crystals were adhered to the surface and which was dry-washed was 0.8 wt% without any treatment, whereas the use of the vibrating sieve reduced the salt content to 0%. It can be reduced to 0.6 wt%, and further, by using the dust separator according to the present invention,
It was possible to halve the salt content to 0.4 wt%.

Next, in the same manner as described above, NaCl crystals were attached to the surface of the plastic piece, washed by dry cleaning, triboelectrically charged, and subjected to electrostatic separation experiment by the electrostatic separation device 5 to verify the separation accuracy. ABS plastic and PVC for plastic pieces
A mixed plastic piece of resin, which has not been subjected to separation treatment and has a salt content of 0.8 wt%, a mixed plastic piece having a salt content of 0.6 wt% which has been subjected to separation treatment using a vibrating screen, and a dust separation device 2 The mixed plastic pieces having a salt content of 0.4 wt% and separated by the electrostatic separation device 5 after triboelectrification and the mixed plastic piece having no salt content of 0% are used. The results obtained are shown in Table 2 and FIG.

In the above experiment, the plastic piece of ABS resin is easily charged to (-) and is separated by the first separation tray 75A, and the plastic piece of PVC resin is easily charged to (+) and is collected on the third separation tray 75C. To be separated.

Here, purity = weight of ABS plastic pieces collected in the first separation tray 75A / weight of all plastic pieces collected in the first separation tray 75A × 100%
And the recovery rate = the weight of the ABS plastic pieces collected in the first separation tray 75A / the weight of all the ABS plastic pieces that have been input × 100%.

[0033]

[Table 2] According to Table 2 and FIG. 3 above, the purity of the ABS resin plastic piece in electrostatic separation sharply drops from around 0.8 wt% salt content, and the recovery rate is 0.4 w salt content.
It has been found that when it exceeds t%, it drops sharply. Therefore, by using the separation / collection device 2 according to the present invention,
It was found that the dust generated in the dry cleaning device can be effectively removed and the separation accuracy of the electrostatic separation device 5 is not reduced.

According to the above embodiment, the plastic pieces discharged from the dry dust collector 1 for rubbing the plastic pieces to clean the surface are introduced into the dust separating device 2, and the plastic pieces are unraveled by the vibration of the mesh plate 36. At the same time, the dust can be effectively removed by suctioning through the mesh plate 36. Further, at this time, since the charge of the plastic piece charged by friction is neutralized by the static eliminator 39, the adsorption of the dust and the plastic piece due to static electricity is released, and even if the dust is extremely small in diameter, it is effective. Can be removed by suction. As a result, a plastic piece can be supplied to the frictional charging device without entraining dust while using a low-cost dry cleaning device, so that the separation accuracy of the electrostatic separation device is not reduced by the dust, and high precision is achieved. It is possible to separate plastic pieces by type.

Further, by providing the dust collecting section 20 in the dry dust collector 1, it is possible to substantially remove coarse dust having a particularly large diameter before the dust separating device 2 is put in, so that the dust removal efficiency can be further improved. it can.

In the above embodiment, the dry dust collector 1 is used.
Although the dust suction unit 20 is provided in the above, even if the plastic piece is directly fed from the dry dust collector without the dust suction section 20, the dust entrained in the plastic piece can be sufficiently sucked and removed, and the separation by electrostatic separation and sparseness is performed. The accuracy is not reduced.

Further, particularly in the case of a heavily soiled plastic piece, the pre-stage dust separation having the same structure as the dust separation device 2 in which the mesh roughness, frequency and amplitude of the mesh plate 36 are set to be suitable for coarse dust having a large diameter The device 81 to the intermediate duct 33
It may be configured such that the dust separating device 2 is used as a post-stage dust separating device to remove dust in two stages, front and rear.

[0038]

As described above, according to the first aspect of the present invention, the plastic piece discharged from the dry dust collector is put on the mesh plate, and the plastic piece is passed through the mesh plate by the vibrating means. By vibrating and stirring and sucking the dust by the dust suction means, the dust separated from the surface can be effectively removed from the plastic piece. While using a low-cost dry cleaning device that does not require drying, the dust generated by cleaning can be effectively removed from the plastic pieces and supplied to the triboelectrification device and electrostatic separation device. The plastic pieces can be separated by type with high accuracy without lowering the separation accuracy.

According to the second aspect of the present invention, the static elimination means neutralizes the electric charge generated by rubbing the plastic pieces to remove the static electricity, so that the plastic pieces are attracted to each other or the plastic pieces and the dust are adsorbed. And can effectively remove dust from plastic pieces.

According to the third aspect of the present invention, coarse dust having a large diameter is sucked and removed from the plastic piece by the mesh plate and the dust suction means of the pre-stage dust removing device, and then the plastic piece is removed by the post-stage dust removing device from the mesh plate. By vibrating above and neutralizing the electric charge of the plastic piece by the static elimination means, the plastic piece and the dust can be separated and the fine dust with a small diameter can be effectively sucked and removed by the suction means. As a result, contaminants on the separated surface can be removed to the extent that the separation accuracy such as purity and recovery rate does not decrease. Therefore, it is possible to effectively remove dust generated by cleaning from the plastic pieces while using a low-cost dry cleaning device that does not require drying, and to supply the triboelectrification device and the electrostatic separation device.
It is possible to separate the plastic pieces by type with high accuracy without lowering the separation accuracy due to the dust.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of a plastic electrostatic separation facility according to the present invention.

FIG. 2 is a side sectional view showing a dust separator of the plastic electrostatic separation facility.

FIG. 3 is a graph showing an experiment result of deposits and separation accuracy in the same plastic electrostatic separation equipment.

[Explanation of symbols]

1 Dry cleaning device 2 Dust separator 3 Friction charging device 4 fixed quantity supply device 5 Electrostatic separator 11 Cleaning casing 12 rotation axes 13 Conveying screw blades 14 Stirring rod 15 Stirring motor 18 Pressure gate 20 Dust suction unit 21 mesh plate 23 Dust collection duct 24 Separation cyclone 25 Rear stage dust suction fan 31 dust collection case 32 entrance 34 exit 36 mesh board 37 mesh vibration device 38 Dust suction device 39 Static eliminator 43 Vibration motor 46 drive link 48 dust duct 49 Separation cyclone 50 Rear stage dust suction fan 51 Corona electrode 61 Charged casing 62 stirring blade 71 drum electrode 72 Counter electrode 73 Electrostatic field 74 High voltage power supply 75A to 75C First to third separation trays

Continued front page    (72) Inventor Hidehiko Maehata             1-89 South Kohoku, Suminoe-ku, Osaka-shi, Osaka             Issue Hitachi Shipbuilding Co., Ltd. F term (reference) 4D021 AA01 AB02 CA07 DA13 DB20                       EA10                 4D054 GA01 GA09 GB01 GB09                 4F301 AA15 AA17 BF08 BF27 BF32

Claims (3)

[Claims] 1. A dry cleaning device for contacting a plastic piece to remove contaminants adhering to the surface, a friction charging device for frictionally contacting the cleaned plastic piece for charging, and a charged plastic piece between the electrodes. In the plastic electrostatic separation equipment provided with an electrostatic separation device for separating the plastic pieces by type by supplying the electrostatic field formed on the surface and changing the falling trajectory, dust between the dry cleaning device and the frictional charging device. A dust removing device is provided, the dust removing device includes a mesh plate that supports the plastic piece from below, a vibrating unit that vibrates the mesh plate, and a dust suction that removes dust entrained in the plastic piece through the mesh plate. And a means for electrostatically separating plastics. 2. A plastic electrostatic separation facility according to claim 1, wherein a static eliminating means for neutralizing the electric charge of the plastic pieces is arranged above the mesh plate of the dust removing device. 3. A dry cleaning device for contacting a plastic piece to remove contaminants adhering to the surface, a friction charging device for frictionally contacting the cleaned plastic pieces with each other, and charging the charged plastic piece as an electrode. In a plastic electrostatic separation equipment equipped with an electrostatic separation device that supplies an electrostatic field formed between and changes a falling trajectory to separate plastic pieces according to types, the plastic cleaning device is incorporated in the dry cleaning device or is a dry cleaning device. A pre-stage dust removing device disposed on the outlet side of the device, and a post-stage dust removing device provided between the pre-stage dust removing device and the frictional charging device, and the pre-stage dust removing means supporting a plastic piece from below. And a dust suction means for sucking and removing dust entrained in the plastic piece through the mesh plate, A mesh plate supported from below, a vibrating means for vibrating the mesh plate, a dust absorbing means for sucking and removing dust entrained in the plastic piece through the mesh plate, and a plastic piece arranged above the mesh plate for removing the plastic piece. A plastic electrostatic separation facility, which is provided with a charge removing unit for neutralizing electric charges.