JP5652779B2 - Fine particle production equipment - Google Patents

Description

  The present invention relates to an apparatus for producing, for example, metal fine particles and ceramic fine particles used for laminated thin film electronic components, fine particles such as pigments used as a raw material of toner, and fine particles such as negative electrodes and positive electrode materials used in secondary batteries. Is.

  Conventionally, as this kind of fine particle manufacturing equipment, wet bead mills that disperse and form solid particles by rotating and stirring ceramic beads in a slurry in which solid particles are suspended in a liquid are widely used. However, there is a problem that the fine particle product is contaminated due to wear of the beads and efficiency is lowered due to separation of the beads and the liquid.

  In addition, a fine particle manufacturing apparatus that develops fine particles by injecting slurry pressurized to a pressure exceeding 200 MPa into a collision space from a plurality of directions and causing them to collide with each other has been developed. Advanced sealing technology and pressure-intensifying technology are required, and there is a problem that the manufacturing cost is high.

  As a fine particle manufacturing apparatus that can cope with such a problem, as shown in FIG. 5, the following patent document 1 accelerates compressed air fed from an air supply source by a jet nozzle 53 of an introduction path 52 and solid particles. Is supplied to the air current of the jet nozzle 53 from the storage tank 54 through the pipe 56 by the driving of the pump 55, and is accelerated by this to rotate the fine liquid droplets injected into the casing 51. It is described that it is made to collide with a colliding member 57 and pulverize the solid particles in the droplets into fine particles.

  As shown in FIG. 6, the jet nozzle 53 includes a convergent portion 53a in which the flow passage diameter gradually decreases in the flow direction, a throat portion 53b in which the flow passage diameter is reduced to the smallest, and a divergent portion in which the flow passage diameter gradually increases. It is a Laval nozzle type provided with 53c.

  In the jet nozzle 53, the discharge pipe 56a of the pipe 56 extends in the flow direction at a position away from the inner wall surface of the throat portion 53b, and is five times as long as the inner diameter of the throat portion 53b from the center of the throat portion 53b to the downstream direction. It arrange | positions so that it may open within the range.

JP 2009-154146 A

  However, the fine particle manufacturing apparatus described in Patent Document 1 has a structure in which the airflow is accelerated only by the Laval nozzle, and the collision member is not sufficiently accelerated in the state where the liquid containing solid particles is in the form of liquid droplets. The solid particles cannot be efficiently pulverized.

  Moreover, since the discharge pipe is provided so as to occupy a part of the cross section of the flow path from the throat portion to the divergent portion, the flow of the air current becomes insufficiently expanded, the speed and flow rate are reduced, and the processing capacity is reduced. In addition to the problem that it is limited, there are problems that it is difficult to position and clean the center of the discharge pipe of the liquid supply pipe, and when the solid particles are adhesive substances, continuous operation for a long time cannot be performed.

  Accordingly, an object of the present invention is to efficiently produce a fine particle product having excellent quality by causing solid particles to collide at high speed with a simple structure without using an advanced sealing technique.

In order to solve the above-described problems, the present invention is a suspension of liquid and solid particles while supplying pressurized gas to an introduction path and accelerating it to a supersonic speed at a Laval nozzle portion of the introduction path. In the fine particle manufacturing apparatus for supplying the slurry into the gas in the introduction path, causing the slurry accelerated thereby to collide with a collision member in the casing, and crushing the solid particles into fine particles, the outlet of the Laval nozzle unit is provided in the introduction path The cross-sectional area expands continuously, accelerates by expanding the supersonic airflow with the corner of the boundary with the outlet of the Laval nozzle as the apex, thereby providing a flare portion for atomizing the slurry into a mist, the flare An opening of the slurry supply unit that supplies the slurry from the side is provided in the part, and the slurry supply unit communicates with the large-diameter hole portion and the small-diameter hole portion, and a pipe from the slurry storage tank is connected to the large-diameter hole portion. Is, it is assumed that the small-diameter hole portion is opened in the wall of the flared portion, the collision member, toward the tip in the center of the outlet of the flare, the mist is subjected to shearing action at the tip portion, the solid particles in the mist dispersion And a conical portion subjected to the micronization action, and a flange portion provided on the outer periphery of the base end side of the conical portion, the supersonic flow along the side surface of the conical portion collides, and the solid particles are impact-pulverized. In addition, a liner is provided on the inner surface of the peripheral wall of the casing to cause the mist that radially protrudes from the flange portion of the collision member to secondarily collide, and the solid particles are impact pulverized.

  In this fine particle manufacturing apparatus, the flaring angle of the flare portion and the flaring angle of the conical portion are in the range of 20 ° to 90 °.

  Furthermore, the axis of the slurry supply section and the vertical line at the center of the conical section intersect each other above the top of the conical section.

  In the fine particle manufacturing apparatus according to the present invention, the slurry is instantaneously atomized (atomized) into a mist by providing a flare portion continuously to the Laval nozzle portion without using a bead mill or the like, and the conical portion of the collision member Collision with the flange part at high speed along the side surface and secondary collision with the liner of the casing make it possible to produce high-quality particulate products without causing problems such as adhesion of particulate matter to the particulate products, which is a problem with bead mills. Solid particles can be pulverized to a particle size range that can be manufactured and cannot be reached by other methods.

  In addition, liquids containing solid particles in a narrow flow path have a simple, safe and economical structure without using advanced sealing technology or pressure-increasing technology, such as those using ultra-high pressure liquids. Therefore, even if the solid particles are an adhering substance, the continuous operation can be performed without causing clogging of the nozzle, and the apparatus can be easily scaled up.

  In addition, since the pulverization process is performed in a closed system, the selection range of high-pressure gas or liquid is wide, and in particular, by using helium gas with a high sonic velocity as the high-pressure gas, the supersonic airflow is further increased and the pulverization performance is improved. Helium gas can also be recycled. Furthermore, the operation sound is quiet and the fine particles do not float in the air around the apparatus, so that adverse effects on the operator and the environment can be prevented.

Whole sectional drawing of the fine particle manufacturing apparatus which concerns on embodiment of this invention Same as above Piping system diagram Overall cross-sectional view of a fine particle manufacturing apparatus according to a reference example Cross-sectional view of conventional fine particle manufacturing equipment Cross section of jet nozzle

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

In the fine particle manufacturing apparatus according to the embodiment shown in FIG. 1, an introduction path 2 is provided in the upper part of a casing 1 composed of a plurality of members, and a Laval nozzle portion 3 is provided in the introduction path 2. The Laval nozzle part 3 includes a convergent part 3a in which the flow path diameter gradually decreases along the flow direction downward from the gas supply port 1a at the upper end, a throat part 3b in which the flow path diameter is reduced to the smallest, and a flow path diameter gradually increases. And a divergent portion 3c.

  Further, the introduction path 2 is provided with a tapered flare portion 4 that is continuous with the outlet of the Laval nozzle portion 3 and has a cross-sectional area that rapidly expands downward. The flare section 4 has a plurality of slurry supply sections 1b that supply a slurry containing solid particles as a raw material from the side.

  A collision member 5 is provided below the flare portion 4 in the grinding space located in the middle of the casing 1. The collision member 5 has a conical part 5a whose front end side is directed toward the center of the outlet of the flare part 4 and a flange part 5b provided on the outer periphery on the proximal end side of the conical part 5a. A shaft portion extending downward from the shaft is inserted into the bearing and is rotatably supported by the casing 1 via a stay member 6 that does not obstruct the airflow.

  Here, the opening in the flare portion 4 of the slurry supply portion 1b is located above the top of the conical portion 5a, and the axis of the slurry supply portion 1b and the vertical line at the center of the conical portion 5a are conical. It intersects above the top of the part 5a. Moreover, although the top part of the conical part 5a corresponds to the height of the exit of the flare part 4, it may enter the inside of the flare part 4.

  A liner 7 is fitted on the inner surface of the peripheral wall of the grinding space of the casing 1. As the material of the collision member 5 and the liner 7, it is preferable to use a ceramic sintered body or a cemented carbide having excellent wear resistance.

  The lower portion of the casing 1 is tapered in a downward direction, and a discharge port 1c through which droplets and mist are discharged is formed at the lower end.

Here, as shown in FIG. 2, when dimensional relations are arranged, in the upper part of the casing 1, the diameter D ₂ of the outlet of the divergent part 3 c is larger than the diameter D ₁ of the throat part 3 b, and the outlet of the flare part 4 than the diameter, the diameter D ₃ of the flange portion 5b of the collision member 5 is larger.

Further, the divergent portion 3c length is the acceleration distance L _1, the length of the flared portion 4 is the acceleration distance L _2.

Then, the flaring angle θ ₂ of the flare portion 4 is larger than the divergence angle θ ₁ of the divergent portion 3 c, and this divergence angle θ ₂ and the divergence angle θ ₃ that is the apex angle of the conical portion 5 a of the collision member 5 Are the same size.

Specifically, θ ₁ is in the range of 3 ° to 10 °, preferably around 4 °, and θ ₂ and θ ₃ are in the range of 20 ° to 90 °, preferably around 60 °.

  A pipe is connected to such a fine particle manufacturing apparatus in a system as shown in FIG. In this piping system, compressed air pressurized to about 0.6 MPa is sent to the gas supply port 1a through the piping 10, and the slurry containing solid particles to be pulverized is pumped from the slurry storage tank through the piping 11 to the pump. Is fed into the slurry supply unit 1b.

In the fine particle manufacturing apparatus, as shown in FIGS. 1 and 2, the subsonic airflow sent from the gas supply port 1a to the introduction path 2 becomes a critical state in the throat portion 3b through the convergent portion 3a, and the sound velocity To reach. That is, when the flow velocity at that position is expressed by Mach number, M1 = 1. The inflated accelerated isentropic manner downstream of the divergent portion 3c over an acceleration distance L _1, Mach number M2 at divergent portion 3c is a Mach number M1 is greater than supersonic at the throat portion 3b.

Next, the supersonic airflow is further accelerated over the acceleration distance L ₂ by the expansion wave generated at the corner of the boundary between the outlet of the Laval nozzle part 3 and the inlet of the flare part 4 and flows into the flare part 4. The Mach number M3 of the airflow is further larger than the Mach number M2 in the divergent portion 3c.

  Along with this, the pressure along the wall surface of the flare part 4 drops abruptly, and the slurry is smoothly supplied from the slurry supply part 1b to the flare part 4, and the slurry collides with the supersonic airflow of M3. Atomized from a droplet into a mist with a diameter of several microns or less.

  The mist ejected from the flare portion 4 into the pulverization space of the casing 1 is subjected to a shearing action by an oblique shock wave formed at the tip portion of the conical portion 5a of the collision member 5, and the solid particles in the mist are dispersed and dispersed. Subjected to micronization.

  Further, the air flow in the pulverization space has a slightly reduced flow velocity, and the Mach number M4 is smaller than the Mach number M3 in the flare portion 4, but the supersonic speed is maintained near the side surface of the conical portion 5a, and the conical shape. It flows smoothly without receiving a back pressure in the vertical direction along the side surface of the part 5a, and this supersonic flow collides with the flange part 5b, and the solid particles in the mist are impact pulverized.

  Furthermore, the mist containing fine particles that have radially ejected from the flange portion 5b in the radial direction collides with the wall surface of the liner 7 again at high speed without losing the speed, and the fine particles are further made into fine particles.

  Here, when the collision member 5 is rotated, the mist uniformly collides with the flange portion 5b, so that uneven wear of the flange portion 5b can be prevented, and a liquid film is generated on the surface of the flange portion 5b, resulting in an impact force. It can be prevented from being reduced. As a means for rotating the collision member 5, a mechanism for rotating by an electric motor may be provided in addition to a mechanism for obtaining a rotational force by causing a supersonic air current to collide with an impeller.

  Thereafter, the airflow including droplets and mist generated by the collision with the wall surface flows downward and is discharged from the casing 1 through the discharge port 1c.

  As shown in FIG. 3, the liquid droplets and mist discharged from the fine particle manufacturing apparatus are sent to the cyclone through the pipe 12 as shown in FIG. 3, but the mist becomes almost liquid droplets inside the pipe 12 and drops in the cyclone. And gas are separated. The separated gas is sent to the bag filter via the pipe 13 through the drying device, and the fine particles are taken out as a product by the bag filter, and the gas from which the fine particles have been removed is exhausted.

  On the other hand, the droplets containing the fine particles are discharged to the pipe 14, returned to the slurry storage tank, stirred, and then sent again to the fine particle production apparatus through the pipe 11 by the pump and repeatedly pulverized. When the predetermined particle size is reached, the slurry containing fine particles is taken out as a product through the pipe 15 by switching the valve. By such a process, fine particles can be formed to a desired particle size.

  Since the process constituted by the pipes 11, 12, and 14 is performed in a sealed state, when a highly ignitable solvent is used as a liquid, there is a risk that the solid particles may become active due to the formation of fine particles. The fine particles can be safely produced by appropriately selecting a liquid or a high-pressure gas.

  Also, helium gas can be used as the high-pressure gas. In this case, since helium gas has a low gas density and a sound velocity of about 1000 m / s, a flow velocity about three times that of air can be easily obtained. Further, almost all of the expensive helium gas can be recovered and reused.

In the fine particle manufacturing apparatus according to the above-described embodiment , the slurry supply unit 1b is arranged so as to supply the slurry to the flare unit 4 from the side. However, as in the reference example shown in FIG. , The slurry supply part 1b is arranged on the upstream side of the throat part 3b of the Laval nozzle part 3 so that the axis coincides with the Laval nozzle part 3, and the compressed air is supplied from the side of the gas supply port 1a upstream of the convergent part 3a. You may provide so that it may supply. This reference example is not included in the scope of the claims.

DESCRIPTION OF SYMBOLS 1 Casing 1a Gas supply port 1b Slurry supply part 1c Discharge port 2 Introduction path 3 Laval nozzle part 3a Convergent part 3b Throat part 3c Divergent part 4 Flare part 5 Collision member 5a Conical part 5b Flange part 6 Stay member 7 Liner 10 15 Piping

Claims (3)

The pressurized gas is supplied to the introduction path (2) and accelerated to supersonic speed by the Laval nozzle part (3) of the introduction path (2), and slurry that is a suspension of liquid and solid particles is introduced into the introduction path ( In the fine particle production apparatus for supplying the gas 2) into the gas and causing the accelerated slurry to collide with the collision member (5) in the casing (1) and crushing the solid particles into fine particles.
In the introduction path (2), the cross-sectional area rapidly expands continuously from the outlet of the Laval nozzle part (3) and accelerates by expanding the supersonic airflow at the corner of the boundary with the outlet of the Laval nozzle part (3). Thus, a flare portion (4) for atomizing the slurry into mist is provided,
The flare portion (4) is provided with an opening of a slurry supply portion (1b) for supplying slurry from the side. The slurry supply portion (1b) has a large diameter hole portion and a small diameter hole portion that communicate with each other. The pipe (11) from the slurry storage tank is connected to the hole, and the small diameter hole is opened at the wall surface of the flare (4).
Conical part (5) where the tip of the collision member (5) is directed toward the center of the outlet of the flare part (4), the mist is subjected to a shearing action at the tip part, and the solid particles in the mist are subjected to the dispersing and atomizing action. 5a) and a flange portion (5b) provided on the outer periphery of the base end side of the conical portion (5a), in which a supersonic flow along the side surface of the conical portion (5a) collides, and the solid particles are shock-pulverized. And a shape consisting of
Further, a liner (7) in which solid particles are impact pulverized by secondary collision of mist that has radially ejected radially from the flange portion (5b) of the collision member (5) on the inner surface of the peripheral wall of the casing (1). An apparatus for producing fine particles, comprising: In particle manufacturing apparatus according to claim 1, the spread angle (theta ₃₎ of the spread angle of the flared portion ₍₄₎ (θ ₂₎ and cone-shaped portions (5a), and a range of 20 ° to 90 ° A fine particle production apparatus characterized by the above. The fine particle production apparatus according to claim 1 , wherein the axis of the slurry supply part (1b) and the vertical line at the center of the conical part (5a) intersect above the top of the conical part (5a). The fine particle manufacturing apparatus characterized by the above-mentioned.

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