JP2006239678A - Separation device and separation method for particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of separating fine particles by particle size regardless of specific gravity by applying a centrifugal force under specific conditions. <P>SOLUTION: The separation device for particles comprises a base stand 11, a disc-type vessel 13 rotating on the base stand 11 and a suspension liquid supply tank 15. The disc-type vessel 13 is provided with a plurality of fan-shaped centrifugal separating tanks 14 arranged at regular intervals in the peripheral direction around the rotation center and a particle supply cylinder 21. The plurality of fan-shaped centrifugal separating tanks 14 are formed as cavities independent to one another which are respectively composed of peripheral side walls 16 and bottom walls 17. The particle supply cylinder 21 is disposed so as to discharge the suspension liquid toward the fan-shaped centrifugal separating tanks 14 from the center part of the disc-type vessel 13, and particles included in the suspension liquid supplied from the suspension liquid supply tank 15 are fractionated into a plurality of particle recovery pockets 22 which are divided in the peripheral direction on the inner surface of the outer side wall of the centrifugal separating tanks. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a particle separation apparatus and a separation method for separating particles in a suspension by particle size or specific gravity.

  Devices that separate two or more types of particles with different specific gravity by specific gravity or particle size using the difference in speed of underwater motion (jigs, tables, cyclones, etc. and their improved devices) are used in various places in the industrial field. Yes.

  The present applicant has already used a specific gravity separation method for separating specific gravity of high specific gravity particles and low specific gravity particles by utilizing the difference in sedimentation velocity depending on the specific gravity of the particles, and applied vibration in the sedimentation direction of the particles, Gravity separation of particles to increase the constant velocity sedimentation ratio, which is the particle size ratio of different density particles that settle at the same speed, by increasing the sedimentation delay of low density particles according to the frequency and amplitude of vibration, greater than that of high density particles A method is proposed (see Patent Document 1).

Further, in a centrifugal separator that separates fine particles from a liquid into a solid and liquid, a configuration in which a partition is rotated by a motor is known (see Patent Document 2).
JP 2003-340314 A Japanese Unexamined Patent Publication No. 63-62562

  In an apparatus that separates two or more kinds of particles with different specific gravities by specific gravity or by particle size using the difference in the speed of underwater motion, the particle motion speed in water represented by sedimentation speed is the specific gravity and particle size of the particles. Because it depends on both (projected cross-sectional area), particles with large specific gravity-small particle size and those with small specific gravity-large particle size move at the same speed, and those with small specific gravity moving at a faster speed, etc. Exists.

  Therefore, in order to accurately separate these particle groups according to specific gravity, in order to prevent the mixing of large and small specific gravity particles, small specific gravity particles having a large particle size that is faster than large specific gravity particles or small particles that are slower than small specific gravity particles. Large specific gravity particles having a particle size must be removed in advance.

  Since particles having a specific particle size cannot be removed by specific gravity in advance, the particle size is usually adjusted to a specific particle size width by a method that allows separation by particle size regardless of specific gravity, such as sieving. Prior particle size adjustment is easy for particles of several millimeters to several centimeters, but it is extremely difficult industrially to adjust fine particles smaller than 50 to 100 μm to a specific particle size range.

  Many conventional separation devices for fine particles have a mechanism for increasing the particle velocity by applying a centrifugal field. However, the centrifugal force is a force that depends on both the specific gravity and the particle size of particles as in the case of gravity, and the time required for separation can be shortened, but there is little effect such as widening the particle size width to be pre-adjusted.

Therefore, in the prior art, it has been impossible to separate polydispersed particles (with a wide particle size range) fine particles by specific gravity (or separation by particle size) with high accuracy. For such polydisperse fine particles, separation by specific gravity with high accuracy using the difference in underwater motion,
(1) By controlling the particle motion during the specific gravity separation and expanding the particle size width to be adjusted in advance, the particle size adjustment in advance is virtually eliminated.
(2) Establish a technology capable of preliminarily adjusting the particle size range required for specific gravity separation and capable of accurately separating fine particles by particle size regardless of particle specific gravity.
Either is required.

  In the invention described in the above-mentioned patent document proposed by the present applicant, a method of controlling particle motion by applying a specific vertical vibration to water and expanding the particle size width to be pre-adjusted (corresponding to (1) above) It is. However, since this method has a limit on the enlargement width, it is difficult to completely eliminate the particle size adjustment.

  The present invention aims to solve such a conventional problem, and by applying a centrifugal force under a specific condition with a technique corresponding to the above (2), fine particles can be obtained regardless of specific gravity. An object of the present invention is to realize a technique that enables separation according to particle size.

  In order to solve the above problems, a base, a disk-shaped container that rotates on the base, and a suspension supply tank are provided, and after the number of rotations of the disk-shaped container reaches a certain number of rotations, A particle separator for separating particles contained in a suspension supplied from a suspension supply tank in a disk-shaped container previously filled with water, wherein the disk-shaped container is disposed around a rotation center thereof. A plurality of centrifuge tanks arranged in the circumferential direction, a particle supply cylinder, and a lid are provided. Each of the plurality of centrifuge tanks includes an inner peripheral wall and a bottom wall, and is formed as an independent recess. And the particle supply cylinder is provided so as to discharge particles in the suspension from the center of the disk-shaped container toward the centrifugal separation tank. .

  A plurality of pockets may be formed on the inner surface of the outer wall of the inner peripheral wall of the centrifugal separation tank, which are divided in the circumferential direction and receive the separated particles.

  In order to solve the above problems, a particle separation method for supplying particles from a suspension supply tank to a disk-shaped container that rotates on a base and separating the particles in the disk-shaped container, wherein the disk-shaped container includes: A plurality of centrifuge tanks disposed in the circumferential direction around the rotation center, a particle supply cylinder, and a lid, each of the centrifuge tanks including an inner peripheral side wall and a bottom wall and independent of each other A particle separation method is provided, wherein the particle separation method is formed as a depression, and the suspension is discharged from the center of the disk-shaped container toward the centrifuge tank through the particle supply cylinder.

  In the conventional separation technology using the difference in motion of underwater particles, the particle size of the target particles needs to be uniform when performing the separation by specific gravity. Only one type of particles was targeted for separation. According to the method of the present invention, high-precision separation can be performed for each specific gravity and particle size with respect to a group of particles having a wide specific gravity and particle size. In addition, “Particle Gravity Separation Method” Japanese Patent Application No. 2002-151669 is a technique of the same purpose as the present case, but the particle size for which this method is effective is limited to a partial particle size region between 10 and 100 μm, Further, since the effect of delaying sedimentation due to vibration is applied, there are disadvantages such as extremely low separation speed. In the method according to the present invention, there is no theoretical limit to the lower limit of the applied particle size, and the separation speed is extremely fast due to the application of the centrifugal field.

  Embodiments of a particle separation apparatus and a separation method for separating particles in a suspension according to the present invention by particle size or specific gravity will be described below with reference to the drawings based on the examples.

(Basic configuration)
The basic configuration and principle of the present invention will be described. In a normal centrifuge or cyclone, the container is filled with suspension-like particles, and the water can move in the direction of rotation, so that both water and particles are delayed from rotation. Coriolis force (an “apparent” force acting in the direction of rotation by rotation) is generated. Countermeasures for this Coriolis force have been studied as being linked to a decrease in the centrifugation speed.

  It is already known that when a radial partition wall is provided in a disk-shaped container (see Patent Document 2), rotation of water is prevented, so that centrifugal force acts efficiently on the particles and the centrifugation speed does not decrease. . The separation device according to the present invention is similar in appearance to the centrifugal separator of this type having a partition wall, but the concept of separation is different, completely blocking the passage of water, and the method for supplying and recovering particles. By changing, separation by particle size is made possible. This point will be described with reference to FIG. 1 which is a conceptual diagram and FIG.

  As shown in the conceptual diagram of FIG. 1, a disc-shaped container 1 is filled with clarified water, and a fan-shaped room in which the water is not completely transported by a radial partition wall 3 centering on the rotating shaft 2 of the disk-shaped container 1. 4 is provided and rotated in one direction around the shaft 2. Alternatively, clear water is filled in an arbitrarily shaped container, and a rotating shaft is provided at a position outside the container to rotate the container in one direction.

  In a state where the rotation of the container 1 is maintained at an arbitrary rotational speed, the particles 6 are released from the particle supply cylinder 5 into the fan-shaped chamber 4 in a direction in which centrifugal force is applied. Since the clarified water is completely restrained in the room 4 by the partition walls 3, the Coriolis force acts only on the particles 6 that can move in the clarified water. The Coriolis force is an apparent force, and its magnitude, that is, the degree of delay from the rotation direction, is determined by the balance between the inertia of the particles 6 and the viscosity of the rotating water.

  When viewed from the outside, the particles 6 gradually move outward by centrifugal action while rotating around the axis of the container 1. That is, the particles 6 move outward while drawing a spiral trajectory. Here, the centrifugal force acting in the centrifugal direction depends on both the specific gravity and the particle size of the particles 6 as in the case of gravity.

  On the other hand, the force acting in the rotation direction is a water pressure gradient. This is a force that attempts to move the particles 6 in the same direction as the rotation of the water by causing a gradient in the pressure of the water applied to the particles as the water rotates. In other words, the water around the particle is the force that acts to move the volume of water in which the particle exists. That is, the pressure gradient is independent of the specific gravity of the particle 6 and is a force that depends only on the particle volume.

  In the centrifugal field (the field where the centrifugal action works), the particles 6 follow the water in the rotation direction and increase the speed in the rotation direction toward the outside, that is, a pressure gradient is applied to the particles 6. Here, particles having the same particle diameter are subjected to the same pressure gradient regardless of the specific gravity. However, if the same force is applied, the movement of the small specific gravity particles having a smaller mass becomes larger. That is, when the movements within the same time are compared, the small specific gravity particles follow the water well, and the larger the specific gravity particles, the longer the delay.

  However, during this time, the movement in the centrifugal direction is smaller for small specific gravity particles and larger for large specific gravity particles. That is, as shown in FIG. 2, in the case of particles of the same particle size having different specific gravities, the difference in motion in the rotational direction caused by receiving the same pressure gradient and the difference in motion in the centrifugal direction caused by receiving different centrifugal forces are taken into account. As a result, the moving speed is slower for the small specific gravity particles and is faster for the large specific gravity particles, but the movement trajectory, that is, the moving direction is substantially the same.

  If all the particles obey this condition, the particle arrangement is as shown in FIG. 3B. However, since the acceleration in the centrifugal direction is actually not constant, only the fine particles have such an arrangement and the particle size becomes large. Therefore, for example, in the case of particles of 1 mm or more, this arrangement is not achieved.

  If the principle explained above is adopted as a particle separation device and a separation method, it is possible to separate the polydisperse fine particles mixed with various specific gravity particles with high accuracy by particle size. In addition, if the particle separation apparatus and method based on this principle are positioned as a prior particle size adjusting means for specific gravity separation, after separating by particle diameter by this means, by using a normal specific gravity separation apparatus for fine particles, Separation by specific gravity is possible.

  Furthermore, after transporting by particle size with this separation means, if the function of a solid-solid separation centrifuge that separates existing solids and solids is added in the same device, high-precision specific gravity can be separated with one device, Separation by particle size can be performed simultaneously.

  FIG. 4 is a diagram for explaining an embodiment of the particle separation apparatus and separation method according to the present invention. In this particle separation device 10, a disk-shaped container 13 is rotatably disposed on a stationary base 11 around a support shaft 12 protruding from the base 11 by a driving device such as a motor (not shown). Yes.

  The disc-shaped container 13 is provided with a pair of fan-shaped centrifuge tanks 14 symmetrically about the support shaft 12. The number and location of the fan-shaped centrifuge tanks 14 in the disk-shaped container 13 may be one or more, and design items to be appropriately designed depending on the scale of the disk-shaped container 13 and the amount of separation processing. It is.

  In the central part of the disk-shaped container 13, a suspension containing particles to be separated mixed in a liquid is accommodated around the support shaft 12, and a fan-shaped centrifuge tank 14 (in the basic configuration described above). A suspension supply tank 15 is provided for supply to “fan-shaped room 4”.

  The fan-shaped centrifuge tank 14 is configured as a hollow from the inner peripheral wall 16 and the bottom wall 17. The inner peripheral wall 16 includes an inner side wall 18, a partition wall (side wall) 19 and an outer side wall 20 that are partitioned in the circumferential direction, and are integrally formed. The fan-shaped centrifuge tank 14 is filled with a liquid such as water, and is configured to be restrained in the fan-shaped centrifuge tank 14 and not flow out even when the disk-shaped container 13 rotates.

  A particle supply cylinder (nozzle) 21 communicating with the suspension supply tank 15 is provided on the inner wall 18 of the fan-shaped centrifuge tank 14. The particles in the suspension filled in the suspension supply tank 15 can be supplied from the particle supply cylinder 21 to the fan-shaped centrifuge tank 14.

  A plurality of particle recovery pockets 22 are arranged in the circumferential direction on the inner surface of the outer wall 20 of the fan-shaped centrifuge tank 14. Each pocket 22 is partitioned by another pocket 22 adjacent to the circumferential direction and a partition wall 23. The separated particles are accommodated in each of the series of the plurality of pockets 22.

  The fan-shaped centrifuge tank 14 has an upper opening that can be closed with a lid 24, and an air vent hole 25 is provided in the lid. Through the air vent hole 25, the fan-shaped centrifuge tank 14 communicates with the atmosphere.

(Function)
The operation of the particle separation apparatus and the separation method having the above configuration will be described below. In order to prevent disturbance of the water in the fan-shaped centrifuge tank 14, water is charged in the suspension supply tank 15 in advance, air bubbles are released from the air vent hole 25, the stopper of the air vent hole 25 is closed, and the suspension supply tank 15 With all the suspension inlets (not shown) open, all the stoppers are closed and sealed.

  When the disk-shaped container 13 starts to rotate and stabilizes at a constant rotational speed, the valve (not shown) that shuts off the suspension supply tank 15 and the particle supply cylinder 21 is opened, and after passing through the particle supply cylinder 21, Particles are released into a fan-shaped centrifuge tank 14 (in the example of the apparatus shown in FIG. 3, it is a two-tank type).

  The suspension supply is not particularly shown, but the suspension supply tank is provided above the disk-shaped container 13, the supply chamber is provided at the center of the disk-shaped container 13, and the suspension supply tank is A pipe communicating with the supply chamber may be provided, and the particles in the suspension may be dropped into the supply chamber through the pipe. And it is good also as a structure which discharges the water containing the particle | grains in the particle | grain collection | recovery pocket 22 with the particle | grains out of an apparatus.

  Further, when supplying to the separation tank, it is important that the particles are released from the same point as much as possible through the particle supply cylinder 21. At this time, if the particle supply cylinder 21 is very thick or the water in the centrifuge tank is greatly disturbed, the particles released to the centrifuge tank easily diffuse and are separated by particle size. The effect is lost. That is, it is desirable that the smaller the inner diameter of the particle supply cylinder 21, the better the separation accuracy, and the water in the centrifuge tank be as stationary as possible with respect to the separation tank.

  The minimum particle size that can be separated depends on the diameter of the rotating body, the number of rotations, the interval between the particle collection pockets 22 and the viscosity of the liquid. As a result of these separation conditions, the distribution of the particles in the pocket 22 where the particles moved most straight in the centrifugal direction from the particle supply cylinder 21 are collected, that is, the distribution of the particles in the pocket 22 where the smallest particle size group is collected, has a lower separation limit. Decide.

  The upper and lower limits of the particle size collected in each pocket 22 are determined by the separation conditions, but only the pocket 22 has no lower limit particle size, and all particles having an upper limit particle size or less are collected. And this upper limit particle diameter becomes a factor which determines the separation lower limit particle diameter in subsequent specific gravity separation.

  For example, when water is used as the liquid, the radius of the rotating body is 400 mm, the interval between the pockets 22 is 20 mm, and separation of small specific gravity particles with a specific gravity of 2.5 and large specific gravity particles with a specific gravity is considered. FIG. 5 shows the relationship between the maximum particle size of the particles in the pocket 22 where the group is collected and the number of rotations. The maximum particle size of the particles in the pocket 22 in which the minimum particle size group is collected is about 7 μm at a rotational speed of 2500 rpm and about 5 μm at 6000 rpm.

  At this time, considering that the particles collected in the pocket 22 are further separated by specific gravity, the lower limit separation particle size corresponding to these maximum particle sizes is a value as shown in FIG. 6 according to the specific gravity of the large specific gravity particles. It becomes. For example, when the separation is performed at a rotational speed of 5000 rpm, the theoretical separation lower limit particle size of the specific gravity separation is about 5 μm when the specific gravity of the large specific gravity particle is 3 and about 2 μm when the specific gravity is 12.

  As described above, according to the separation method of the present invention, it is theoretically possible to perform the specific gravity separation of polydisperse fine particles of several μm or more having a particle size width that cannot be separated conventionally (with a separation efficiency of nearly 100%). It is.

  The particle separation apparatus and the separation method for particles according to the present invention have been described with reference to the embodiments. However, the embodiments of the present invention are not limited to the above-described embodiments, and are within the technical scope of the claims. Needless to say, there are various modes.

Industrial applicability

  The particle separation apparatus and separation method for separating particles in suspension according to particle size or specific gravity according to the present invention require various types of particles that require separation of particles in suspension by particle size or specific gravity. Applicable to industrial fields (manufacturing processes in mining and various industrial fields, particle separation processes in recycling and environmental restoration processes, etc.).

It is a figure explaining the fundamental composition and method of a particle separation device and a separation method concerning the present invention. FIG. 3 is a diagram for explaining the basic configuration of the particle separation apparatus and the separation method according to the present invention and the operation of the method (the movement of the particles in the separation tank is explained with a view of the centrifugal separation tank in the disk-shaped container as viewed from above). is there. FIG. 3 is a diagram for explaining the basic configuration of the particle separation apparatus and the separation method according to the present invention and the operation of the method (the movement of the particles in the separation tank is explained with a view of the centrifugal separation tank in the disk-shaped container as viewed from above). is there. It is a figure explaining Example 1 of a particle separation device and a separation method concerning the present invention. It is a figure explaining the operation of the particle separation device and the separation method according to the present invention, and the relationship between the maximum particle size of small specific gravity particles recovered in the pocket where the minimum particle size particle group is recovered and the rotational speed (separation lower limit). It is a figure which shows the theoretical calculation value regarding the largest particle size of the small specific gravity particle | grains in the minimum particle group collection | recovery pocket 22 which is a factor which determines a particle size. It is a figure explaining the effect | action of the particle | grain separator which concerns on this invention, and the separation method, and with respect to the particle group collect | recovered in the pocket at each rotation speed, the specific gravity and specific gravity separation lower limit (separated on the conditions of FIG. 5). It is a figure which shows the separated particle diameter lower limit at the time of carrying out the specific gravity separation of the particle group in the minimum particle group collection pocket 22 for every specific gravity of a large specific gravity particle).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Disc type container 2 Container rotation axis 3 Bulkhead 4 Fan-shaped room 5 Particle supply cylinder 6 Particle 7 Particle with large specific gravity 8 Particle with small specific gravity 10 Separating device by particle size 11 Base 12 Support shaft 13 Disk type container 14 Fan shape Centrifugal separator 15 Suspension supply tank 16 Inner wall 17 Bottom wall 18 Inner wall 19 Partition wall (side wall)
20 Outer wall 21 Particle supply cylinder 22 Particle recovery pocket 23 Partition wall 24 Lid 25 Air vent hole

Claims (3)

A base, a disk-shaped container that rotates on the base, and a suspension supply tank, and particles contained in the suspension supplied from the suspension supply tank in the disk-shaped container A particle separation device for sorting,
The disk-shaped container comprises a plurality of centrifuge tanks arranged in the circumferential direction around the center of rotation, a particle supply cylinder, and a lid,
The plurality of centrifuge tanks are each formed of an inner peripheral wall and a bottom wall and are formed as indents independent of each other,
The particle supply cylinder is provided so as to discharge particles in the suspension from the center of the disk-shaped container toward the centrifuge tank filled with water in advance. apparatus.   2. The particle separator according to claim 1, wherein a plurality of pockets are formed on the inner surface of the outer wall of the inner peripheral wall of the centrifugal separation tank and are divided in the circumferential direction to receive the separated particles. . A particle separation method in which a suspension is supplied from a suspension supply tank to a disk-shaped container that rotates constantly on a base, and particles contained in the suspension are separated in the disk-shaped container,
The disk-shaped container includes a plurality of centrifuge tanks, particle supply cylinders, and lids arranged at equal intervals in the circumferential direction around a rotation center thereof, and the centrifuge tanks each have an inner peripheral side wall. And the bottom wall are formed as indents independent of each other,
A particle separation method, wherein the particles in the suspension are discharged from the central part of the disk-shaped container through the particle supply cylinder toward the centrifuge tank filled with water in advance.