JPH10235228A - Electrostatic sorting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic sorting device enabling improving of sorting efficiency by giving the sufficient charged quantity to fine powder particles. SOLUTION: In an electrostatic sorting device in which powder to be sorted is caused to settle by gravity in an electrostatic separator and a DC electric field is generated between a pair of parallel flat electrode plates 6A, 6B installed along the gravity settling direction of the powder to be sorted, causing the powder to be sorted to be separated according to the charged quantity, on the upstream side of the parallel electrode plates, an electrifying part consisting of a discharge electrode 12 having plural projections and a ground electrode 13 installed around the discharge electrode 12 is provided, and high voltage is applied to between both the electrodes 12, 13 by a DC high voltage power source 14, allowing corona discharge to be generated to charge the powder to be sorted with electricity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic separation apparatus for electrostatically selecting a target component from a mixture of fine powder particles comprising two or more different components.

[0002]

2. Description of the Related Art An electrostatic separation apparatus that charges a mixture of fine powder particles and applies an electric field to the fine powder particles to electrostatically select a target component has been widely used. A specific example of such an electrostatic sorting device is disclosed in
No. 113855 is known.
FIG. 2 is a perspective view showing the overall configuration.

[0003] As shown in FIG. 2, fine powder particles such as coal are charged from an upper charging port 2 of a casing 1 made of an insulating material. These fine powder particles are classified according to the size of the mesh of the sieve 4 by a mesh electrode sieve 4 fixed to the casing 1 with inclination by the supporting insulators 3A and 3B. That is, particles larger than the mesh are taken out of the apparatus, and particles smaller than the mesh pass through the mesh electrode sieve 4 and fall on the ground electrode 5. At this time, a high voltage is applied between the mesh electrode sieve 4 and the ground electrode 5, and the fine powder particles that have fallen through the sieve 4 are inductively charged with a charge amount difference corresponding to the component.

[0004] The fine powder particles charged in the charging section in this way are supplied to an electrostatic separation section provided below the charging section. A DC or AC electric field is generated between the parallel plate electrodes 6A and 6B in the electrostatic separation portion, and the charged particles supplied from the upper charging portion and falling by gravity are charged by the electric field according to the charge amount. The fall trajectory is controlled. Therefore, the particles having a large particle diameter and the particles having a small particle diameter pass through different falling trajectories, and are separated and collected in the sorting hopper 7.

[0005]

In the above-mentioned conventional powder sorting apparatus, in the charging section, the mesh electrode sieve 4 and the ground electrode 5 are used.
The fine particles are inductively charged by the electric field generated by the application of a high DC or AC voltage applied between them, but the charging by the induction charging does not give a sufficient amount of charge to the fine particles, resulting in high precision. Could not be sorted.

Further, most of the charged particles that have fallen on the ground electrode 5 in the charging section come into contact with the ground electrode 5 and lose the charge of the charged particles at that time, so that the charging efficiency is significantly reduced. It will be.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an electrostatic sorting capable of giving a sufficient amount of charge to fine powder particles and thereby improving the sorting efficiency. It is to provide a device.

[0008]

SUMMARY OF THE INVENTION An electrostatic sorting apparatus according to the present invention comprises a step of gravity-separating powder to be selected, and applying a direct current between a pair of parallel plate electrodes provided along the direction of gravity of the powder to be sorted. In the electrostatic sorting device that separates the powder to be settled between the parallel electrode plates in accordance with the charge amount by generating a field, the electrostatic sorting device has a plurality of protrusions on the upstream side of the parallel plate electrode. A charging section comprising an electrode and a ground electrode provided around the discharge electrode is provided, and by applying a high DC voltage between the two electrodes, a corona discharge is generated to charge the powder to be sorted. Features.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an overall configuration of an electrostatic sorting device according to one embodiment of the present invention. As shown in FIG. 1, a fine powder particle supply unit 11 made of an insulating material having a slit at the bottom is provided to supply the fine powder particles to be sorted powder in a sheet shape, and this supply unit 11 is not shown. Fine powder particles pulverized by a pulverizer or the like are guided. A discharge electrode 12 having a plurality of needle-like projections is provided below the fine powder particle supply unit 11, that is, downstream of the gravity sedimentation direction.
And a charging unit including a ring-shaped ground electrode 13 provided to surround the discharge electrode 12 so as to face the discharge electrode 12. A DC high-voltage power supply 14 for exciting corona discharge is connected between the terminals 13.

Downstream of the discharge electrode 12 and the ground electrode 13 in the direction of gravity sedimentation, a pair of parallel plate electrodes 6A and 6B are provided along the direction of gravity sedimentation. A DC high-voltage power supply 15 is connected to these parallel plate electrodes 6A and 6B, and a DC electric field for changing the falling trajectory of the fine particles charged between the electrodes 6A and 6B between the components of the fine particles by the power supply 15 is provided. Are formed perpendicular to the direction of gravity settling.

Below the parallel plate electrodes 6A and 6B, a hopper 7 for collecting and collecting the selected charged particles is provided. That is, the hopper 7 is divided into a plurality of chambers so that the components of the fine powder particles falling through different falling trajectories on the parallel plate electrodes 6A and 6B are collected at different positions.

The operation of the electrostatic sorting device according to this embodiment will be described. First, the fine powder particles supply unit 11 stores fine powder particles composed of two or more different components having a particle diameter of, for example, several tens μm to several hundred μm. The fine powder particles in the fine powder particle supply unit 11 continuously fall into a sheet shape from the slit at the lower part thereof, and are supplied to the charging unit. The fine powder particles supplied to the charging unit fall between the discharge electrode 12 and the ground electrode 13 provided therearound.

A high DC voltage is applied between the discharge electrode 12 and the ground electrode 13 by a DC high voltage power supply 14. Due to the application of the high voltage, an uneven electric field is formed due to the difference in shape between the electrodes 12 and 13. Therefore, even when the DC high-voltage power supply 14 has a relatively low voltage, a locally high electric field is generated, and corona discharge is excited.

Here, when the fine particles enter the uneven electric field region between the two electrodes 12 and 13, the unipolar ions generated by the corona discharge are driven by the electric field, and the electric field charges which are projected and charged on the particle surface. , And diffusion charging, which rushes onto the particle surface due to the thermal motion of ions, and is instantaneously charged by two different charging mechanisms.

Some of the charged particles move toward the ground electrode 13 due to the Coulomb force and are collected, but most of the charged particles retain their electric charge while holding the ground electrode 1.
3 and the lower parallel plate electrode 6
A falls by gravity between A and 6B.

Here, depending on the difference of the main components forming fine powder particles, for example, SiO ₂ , C, etc., that is, the difference of the particle size and relative dielectric constant of the charged particles, the charged portion composed of the discharge electrode 12 and the ground electrode 13 has Since a difference occurs in the charge amount, the fall trajectory between the parallel plate electrodes 6A and 6B is controlled according to the charge amount. Thereby, the parallel plate electrodes 6A, 6A
The charged particles dropped between B are separated into different components such as a conductor, a semiconductor, and an insulator, and are sorted and collected by the hopper 7.

As described above, since the fine particles are charged by corona discharge, the maximum charge can be achieved in a short time.
Further, since the contact with the ground electrode is reduced, the loss of the charge amount is reduced, and the charging efficiency of the fine powder particles is improved. The present invention is applicable to the sorting of various industrial wastes and the like.
The present invention is also applicable to a device for collecting particles.

[0018]

As described above, according to the present invention, the powder to be sorted is charged and gravity sedimented, and the powder to be sorted is segregated by a DC electric field between a pair of parallel flat electrodes provided along the direction of gravity sedimentation. In an electrostatic sorting device that performs sorting by separating powder according to the charge amount, a charging unit is configured by a discharge electrode having a plurality of protrusions and a ground electrode provided around the discharge electrode,
By applying a high DC voltage between the two electrodes to generate corona discharge, the powder to be sorted can be charged effectively in a short time, and the contact between the powder to be sorted and the ground electrode can be reduced. Since the loss of the charge amount can be reduced by reducing the amount, the sorting efficiency is remarkably improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the overall configuration of an electrostatic sorting device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the overall configuration of a conventional powder sorting apparatus.

[Explanation of symbols]

 6A, 6B Parallel plate electrode 7 Hopper 11 Fine powder particle supply unit 12 Discharge electrode 13 Ground electrode 14, 15 DC high voltage power supply

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Minamiyama 2-19-19 Shinhama, Arai-cho, Takasago-shi, Hyogo Prefecture Inside Takahashi Engineering Co., Ltd.

Claims (1)

[Claims] 1. A method according to claim 1, wherein the selected powder is sedimented by gravity, and a DC electric field is generated between a pair of parallel flat electrodes provided along the direction of gravity sedimentation of the selected powder, whereby the distance between the parallel electrode plates is reduced. An electrostatic sorting apparatus that separates the sedimented powder to be settled according to its charge amount, comprising: a discharge electrode having a plurality of protrusions on an upstream side of the parallel plate electrode; and a ground electrode provided around the discharge electrode. An electrostatic sorting device comprising: a charging section comprising: a high-voltage direct current applied between the two electrodes to generate corona discharge to charge the powder to be sorted;