JP2003181323A - Method and device for manufacturing fine particles from brittle material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture fine particles of a fine particle-size at a low cost in a rather simple structure by applying a dry pulverizing. <P>SOLUTION: Particles made from brittle material are heated in a temperature lower than the softening temperature and the heated particles are rapidly cooled down to generate cracks in each particle. By injecting a mixed gas at high pressure where the particles having cracks are scattered in the gas supplied by a high pressure gas supply means 20 to a flow passage arranged with cutting blades to face each other, the particles having cracks are pulverized at least by the impact energy with the cutting blade. The particles are circulated by returning to the flow passage and the pulverizing process is repeated. The particles pulverized by repeatedly passing the flow passage are collected into a reservoir 41 communicating with the flow passage. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing fine particles made of a brittle material. INDUSTRIAL APPLICABILITY The present invention can be suitably used particularly for a dry pulverizing method and a dry pulverizing apparatus for pulverizing glass particles.

[0002]

2. Description of the Related Art Conventionally, in order to produce fine particles (fine powder) made of a brittle material such as glass or ceramic, a dry or wet fine pulverizer is used. Among them, as a dry type fine pulverization device, a device using a roller mill, a ball mill or the like is generally used. This dry fine pulverizer applies a mechanical impact to the powder by a roller mill, a ball mill or the like, and brittlely breaks the powder by mechanical energy to obtain a fine powder having a small particle size (particle size).

[0003]

In the conventional fine pulverizing apparatus, the wet fine pulverizing apparatus can usually produce fine powder having a finer particle size (smaller particle size) than the dry fine pulverizing apparatus. . That is, when the particle size of the target powder is in the fine particle size range of submicron, the powder adheres to the grinding medium (ball mill or roller mill) or the inner wall of the grinder in the dry pulverization device, and has a cushioning effect. This is because the pulverization does not proceed smoothly, and on the contrary, the possibility of accelerating the fixation and agglomeration of the powder increases. In such a fine particle size range, it is common to use a wet pulverization device to suspend the powder in the liquid to wet the particle surface and perform the pulverization treatment in a state where the interaction between the particles is weakened. Target. On the other hand, the wet pulverizing apparatus generally has a complicated overall structure and is expensive. Therefore, the manufacturing cost of the manufactured fine particles themselves also increases.

Therefore, in the present invention, by adopting the dry fine pulverization, a fine pulverization method and fine pulverization of fine particles made of a brittle material capable of inexpensively producing fine particles having a fine particle size with a relatively simple structure. The object is to provide a device.

[0005]

According to a first aspect of the present invention, there is provided a method for producing fine particles made of a brittle material, wherein a heating step of heating particles made of the brittle material and a step of rapidly cooling the heated particles to crack each particle. It comprises a quenching step of generating and a pulverizing step of mechanically pulverizing the particles having the cracks.

A method for producing fine particles made of a brittle material according to a second aspect comprises a heating step of heating the particles made of the brittle material at a temperature lower than a softening temperature, and rapidly cooling the heated particles to cause cracks in each particle. A quenching step to generate, a gas mixture in which particles having the cracks are dispersed in a gas is jetted at a high pressure to a flow path in which a cutting blade is arranged to face, and is circulated by circulating in the flow path, at least the cutting blade and And a finely pulverizing step of finely pulverizing the particles having the cracks by the collision energy.

A method for producing fine particles made of a brittle material according to a third aspect of the present invention comprises a heating step of heating particles made of the brittle material at a temperature lower than a softening temperature, and rapid cooling of the heated particles to cause cracks in each particle. A quenching step to generate, a mixture of particles having the cracks dispersed in the gas supplied from the high-pressure gas supply means, by injecting at high pressure into the flow path in which the cutting blades are arranged facing each other, at least the cutting blades A finely pulverizing step of finely pulverizing the particles having the cracks by the collision energy of the particles, circulating the particles to the flow path for circulation, repeating a fine pulverizing step, and repeatedly passing through the flow path. And a collection step of collecting the finely pulverized particles in a storage chamber communicating with the flow path.

According to a fourth aspect of the present invention, there is provided a method for producing fine particles made of a brittle material, wherein the particles made of the brittle material are glass particles, and the glass particles are made of glass in the heating step. It is heated at a temperature below the transition temperature.

A method for producing fine particles made of a brittle material according to a fifth aspect is the method according to any one of the second to fourth aspects, wherein in the finely pulverizing step, the air-fuel mixture is directed in the axial direction of the flow path. It is introduced into the flow path in an inclined state.

According to a sixth aspect of the present invention, there is provided a method for producing fine particles made of a brittle material according to any one of the second to fifth aspects, wherein the storage chamber is maintained in a substantially vacuum state, and the finely pulverizing step and the collecting step are performed. And, in the circulation step, the introduction speed of the air-fuel mixture introduced from the high-pressure gas supply means to the flow path is increased.

According to a seventh aspect of the present invention, there is provided an apparatus for producing fine particles made of a brittle material, which comprises heating means for heating the particles made of the brittle material, and rapid cooling means for rapidly cooling the heated particles to generate cracks in each particle. Finely pulverizing means for mechanically finely pulverizing the particles having the cracks.

According to an eighth aspect of the present invention, there is provided an apparatus for producing fine particles made of a brittle material, wherein heating means for heating the particles made of the brittle material at a temperature lower than a softening temperature and rapid cooling of the heated particles to cause cracks in each particle. A quenching means to generate, and a gas mixture in which particles having the cracks are dispersed in a gas are jetted at a high pressure to a flow path in which a cutting edge is arranged to face and circulate and circulate in the flow path, at least the cutting edge. And a finely pulverizing means for finely pulverizing the particles having the cracks by the collision energy.

According to a ninth aspect of the present invention, there is provided an apparatus for producing fine particles made of a brittle material, wherein heating means for heating the particles made of the brittle material at a temperature lower than the softening temperature and rapid cooling of the heated particles to cause cracks in each particle. A quenching means to be generated, and a mixture of particles having the cracks dispersed in the gas supplied from the high-pressure gas supply means, by injecting at high pressure into a flow path in which the cutting edges are arranged at least, and at least the cutting edges. A finely pulverizing means for finely pulverizing the particles having the cracks by collision energy, a circulating means for circulating the particles by circulating them back to the flow channel, and repeating the finely pulverizing step, and a storage chamber communicating with the flow channel. And collecting means for collecting finely pulverized particles that have repeatedly passed through the flow path into the storage chamber.

According to a tenth aspect of the present invention, in the apparatus for producing fine particles made of a brittle material, the particles made of the brittle material are glass particles, and the heating means transforms the glass particles into a glass transition material. Heat at a temperature below temperature.

According to an eleventh aspect of the present invention, in the apparatus for producing fine particles made of a brittle material, in the structure according to any one of the eighth to tenth aspects, the finely pulverizing means directs the air-fuel mixture in the axial direction of the flow path. It is introduced into the flow path in an inclined state.

According to a twelfth aspect of the present invention, in the apparatus for producing fine particles of a brittle material according to any one of the eighth to eleventh aspects, the storage chamber includes a depressurizing means for maintaining the inside in a substantially vacuum state. By maintaining the inside of the storage chamber in a substantially vacuum state by means, the introduction speed of the air-fuel mixture introduced from the high-pressure gas supply means to the flow path is increased.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. Throughout the embodiments, the same members, elements or portions are designated by the same reference numerals, and the description thereof will be omitted.

[Embodiment 1] {Manufacturing apparatus} FIG. 1 is a block diagram schematically showing main components of a manufacturing apparatus of fine particles made of a brittle material according to a first embodiment of the present invention. FIG. 2 is a sectional view schematically showing a main part of a fine pulverizing means of the apparatus for producing fine particles made of a brittle material according to the first embodiment of the present invention.

The apparatus for producing fine particles made of a brittle material according to the first embodiment comprises a heating means, a quenching means and a fine pulverizing means. The heating means is for heating particles made of a brittle material. The quenching means is for rapidly cooling the heated particles to generate cracks in each particle. As the particles made of the brittle material, inorganic particles, organic particles, inorganic glass particles, organic glass particles,
Particles of any brittle material such as ceramic particles can be used. In Embodiment 1, it is preferable to use inorganic glass particles such as silica glass (quartz glass) and borosilicate glass as the particles made of the brittle material. Specifically, as the inorganic glass particles, Si02
Na2CaO glass, TiO2BaOSi02ZnO
Glass, TiO2BaOZrO2ZnO glass, S
i02CaOAl2O3B2O3 glass, Si02A
Glass particles such as 12O3CaOMgOB2O3 glass can be used. Also, these glass beads can be used as the glass particles. On the other hand, when particles other than glass particles are used, for example, crystalline particles such as silica particles (SiO2) can be used as the inorganic particles.

As the heating means, any means can be used as long as the particles made of a brittle material can be heated. For example, a direct heating means such as an electric heater may be used as the heating means, particles made of a brittle material such as glass particles may be housed in a container, and the container may be directly heated by the heating means. Further, as the quenching means, any means can be used as long as the particles made of the brittle material can be rapidly cooled. For example, as a quenching means, a cooling medium such as liquid nitrogen or liquid hydrogen is used, and the cooling medium is housed in a container, and heated particles are put into the container, and the particles are directly quenched by the cooling medium. Good. Alternatively, the container containing the heated particles may be cooled with a cooling medium to indirectly and rapidly cool the particles.

As shown in FIG. 1, the finely pulverizing means 10 is for mechanically finely pulverizing the particles having the cracks. Specifically, as shown in FIG. 2, the finely pulverizing means 10 has a housing 11, and a first flow path 11a is formed through the housing 11. First channel 1
1a has a linear shape with a circular cross section that extends along the axis of the housing 11. A second flow passage 11b is continuously formed at a downstream end of the flow passage 11a of the housing 10 with a step. The second channel 11b is the first channel 1
It has a linear shape having a circular cross section with a diameter larger than 1a. In the second flow passage 11b of the housing 11, a cutting blade 12 is arranged and fixed so as to face the downstream end of the first flow passage 11a. The cutting blade 12 has a blade surface 12a obtained by inclining only one side surface. Further, the cutting blade 12 has a lower end by a fixing means (not shown) such as a chuck so that its cutting edge (the tip edge of the blade surface 12a) 12x is positioned to face the center of the downstream end of the first flow path 11a of the housing 11. The side is fixed. The cutting edge 12 can be formed of a metal or alloy for a normal cutting edge. In this case, the cutting edge 12x can be sharpened to a radius of curvature of about 1 μm by a normal mechanical polishing, for example. The cutting edge 12 can also be formed of a superhard material such as diamond. For example, when the cutting edge 12 is formed of diamond, which is the hardest material on the earth, the cutting edge 12x has, for example, a polishing technique using powdered diamond or a polishing technique using ion sputtering (focused ion beam or electron beam on the cutting blade surface). The radius of curvature of the tip is approximately 30 nm to 1 by polishing by applying and polishing.
It can be sharpened to 00 nm.

The apparatus for producing fine particles made of a brittle material according to the first embodiment further includes a high pressure gas supply means 20 and a mixture gas inflow chamber 30. The high-pressure gas supply means 20 and the air-fuel mixture inflow chamber 30 are connected by a pipe line 15 so that the high-pressure gas from the high-pressure gas supply device 20 can flow into and inject into the air-fuel mixture air flow chamber 30 at a high pressure through the pipe line 15. It has become. As the high-pressure gas supply unit 20, any unit can be used as long as it can supply an arbitrary high-pressure gas (gas). For example, the high pressure gas supply means 20
As the gas cylinder, a high pressure gas such as argon gas, hydrogen gas or nitrogen gas can be stored and the high pressure gas can be injected at a desired pressure through a pressure adjusting means such as a valve. The air-fuel mixture inflow chamber 30 has a conduit 25.
It forms a container (housing) into which high-pressure gas can flow in and inject through. The air-fuel mixture inflow chamber 30 is
It is connected to the fine crushing means 10 via a flow path 35. That is, the air-fuel mixture inflow chamber 30 has the flow passage 35 communicating with the inside thereof, and the downstream end of the flow passage 35 has the fine pulverizing means 1
No. 0 crushing means 10 is connected to the upstream end of the first flow path 11a. Then, the high-pressure gas that has flowed from the high-pressure gas supply means 20 into the air-fuel mixture inflow chamber 30 flows and is injected into the first flow passage 11 a and the second flow passage 11 b of the fine pulverization means 10 via the flow passage 35. It is like this. The air-fuel mixture inflow chamber 30 is not provided with the flow passage 35 communicating with the inside thereof, but with a separate conduit communicating with the flow passage 35.
You can also connect to.

The apparatus for producing fine particles made of a brittle material according to the first embodiment further includes a collecting means 40 and a circulating means 50.
Is equipped with. The collection means 40 has a container-shaped powder storage chamber 41 that communicates with the second flow path 11b of the fine pulverization means 10. A powder loading / unloading port 42 is openably and closably provided at the upper end of the powder storage chamber 41.
The powder can be put in and taken out from the inside by opening the chamber, and the inside of the powder storage chamber 41 can be kept airtight by closing the powder loading / unloading port 42. There is. The collecting means 40 collects the particles, which have passed through the second flow path 11b of the finely grinding means 10 and are finely ground, in the powder storage chamber 41. Powder storage chamber 41
Through the flow path 15 to the second flow path 1 of the finely pulverizing means 10.
It is connected to 1b. That is, the collecting means 40 includes the powder storage chamber 41 and the downstream end of the second flow path 11b of the fine pulverizing means 10.
Has a flow path 15 that communicates with the inside. Then, the high-pressure gas from the second flow passage 11b of the finely pulverizing means 10 is made to flow into and be injected into the powder storage chamber 41 via the flow passage 15. The powder storage chamber 41 may be connected to the second flow passage 11b of the fine pulverizing means 10 not via the flow passage 15 but via a separate conduit communicating with the flow passage 15. However, when the second flow passage 11b of the fine pulverizing means 10 and the powder storage chamber 41 are connected by the flow passage 15,
The housing 11 of the finely pulverizing means 10 and the powder storage chamber 41 of the collecting means 40 can be integrally connected. In this case, since the cutting edge 12 can be fixed to the powder storage chamber 41 side, the configuration can be simplified. For example, a fixing means such as a chuck for fixing the cutting blade 12 is arranged and fixed at the central portion of the powder loading / unloading port 42, and the cutting blade 12 is fixed to the fixing means so that the cutting blade 12 is housed. While being accommodated in the second flow channel 11b of 11,
The cutting edge 12x of the cutting blade 12 is connected to the first flow path 1 of the housing 11.
It can be arranged facing the center of the downstream end of 1a.
That is, by simply fixing the cutting blade 12 and its fixing means as a unit to the powder storage chamber 41, the housing 11
Cutting edge 12 for the first and second flow paths 11a, 11b of
Can be easily positioned.

The circulation means is for circulating the particles in the powder storage chamber 41 of the collection means 40 from the powder storage chamber 41 to the first flow path 11a of the fine pulverization means 10 for circulation. It is a thing. In detail, the circulation means has the conduit 45 and the pressure adjusting means 50. One end of the pipe line 45 communicates with the inside of the powder storage chamber 41 of the collecting means 40, and the other end is connected to the pressure adjusting means 50. Then, the high-pressure gas inside the powder storage chamber 41 is passed through the pipe line 45 and the pressure adjusting means 50, and the high-pressure gas in the mixture storage chamber 3
It is refluxed to 0 and further circulated to the fine pulverizing means 10. The pressure adjusting means 50 is for keeping the pressure inside the air-fuel mixture inflow chamber 30 constant and for keeping the pressure of the high-pressure gas flowing from the air-fuel mixture inflow chamber 30 into the flow paths 11a and 11b of the fine pulverizing means 10 constant. Is. Pressure adjusting means 50
Has members such as a check valve (check valve) and a relief valve (relief valve).
Of high pressure gas from the mixture gas inflow chamber 35 into the pipe line 45, high pressure gas in the mixture gas inflow chamber 35 from flowing back to the pipe line 45, or the pressure in the mixture gas inflow chamber 35 is reduced. It prevents it from becoming abnormally high. The pressure adjusting means 50 may be of a type that is directly provided at a connection port between the mixture gas inflow chamber 30 and the other end of the pipe line 45, or a unit type that is separately provided between the mixture gas inflow chamber 30 and the other end of the pipe line 45. It may be one of

{Manufacturing Method} Next, a method of manufacturing fine particles made of a brittle material using the manufacturing apparatus configured as described above will be described. FIG. 3 shows the first embodiment of the present invention.
6 is a flowchart showing steps of a method for producing fine particles made of a brittle material according to the above.

In the method for producing fine particles made of a brittle material according to the first embodiment, particles (powder) made of a brittle material for forming fine particles (fine pulverization) in the powder preparation step STEP1.
To prepare. In the present embodiment, glass particles are prepared as particles made of brittle material. Next, powder heating step ST
In EP2, using a heating means, the prepared glass particles (powder) are heated under predetermined heating conditions (heating temperature, heating time, etc.). At this time, the heating condition is determined in consideration of the composition and physical properties (coefficient of thermal expansion) of the particles made of the brittle material, and the temperature is at least lower than the melting point, preferably lower than the softening temperature. That is, preferably the particles are at a temperature below the softening temperature (more preferably at a temperature well below the softening temperature).
Heat to In the case of glass particles, the glass particles are preferably heated to a temperature below the glass transition temperature (more preferably a temperature sufficiently lower than the glass transition temperature). In the case of glass particles, it is usually about 100 ° C to 300 ° C.
The heating conditions are set so that the temperature is in the range of 150 ° C, preferably in the range of 150 ° C to 250 ° C, and more preferably about 200 ° C. Next, in the powder quenching step STEP3, the particles in a heated state (high temperature state) are rapidly cooled under a predetermined cooling condition (cooling temperature, cooling time, etc.) by using a quenching means, and each particle is cracked. Generate. At this time, the cooling conditions are determined in consideration of the composition and physical properties (coefficient of thermal expansion) of particles made of brittle material. The cooling temperature of the particles by the quenching means can be any temperature as long as the particles can be effectively cracked. In the case of glass particles, it is usually cooled at a temperature in the range of about −100 ° C. to 200 ° C., preferably about −150 ° C. for several seconds.

The heating and cooling conditions will be described in detail. In the case of glass particles, cracks occur in the glass particles due to the generation of stress due to the temperature difference between the glass surface and the inside due to the coefficient of thermal expansion. That is, since the glass surface has a lower temperature than the inside, if the coefficient of thermal expansion is positive in the temperature range considered, tensile stress is generated on the surface and compressive stress is generated on the inside. The tensile stress on the surface promotes the extension of cracks existing on the glass surface, and causes the glass to break.
For example, when the glass has a parabolic temperature distribution, the stress distribution also has a parabolic shape, and the compressive stress acting on the glass and the tensile stress acting on the glass surface are given by the following equations.

Tensile stress σ = −Eα (T1−Ts) / 3 (1−ν)

Compressive stress σ = 2Eα (T1-Ts) / 3 (1-ν)

Here, E, ν, and α are the Young's modulus, Poisson's ratio, and thermal expansion coefficient of the glass, respectively. Also,
T1 and Ts are the temperature inside and on the surface of the glass, respectively.

Therefore, the larger the coefficient of thermal expansion of glass, the greater the stress caused by the temperature change, and as a result, the glass particles are more likely to crack. Therefore, it is preferable to appropriately determine the heating temperature and the cooling temperature, and the heating time and the cooling time according to the thermal expansion coefficient of the glass.

Then, the powder heating step STEP2 and the powder rapid cooling step STEP3 are repeated a plurality of times. As a result, it is possible to enlarge the cracks generated in the particles and increase the number of cracks. Powder heating process STE
The number of repetitions of P2 and the powder quenching step STEP3 is determined in consideration of the composition and physical properties (coefficient of thermal expansion) of particles made of a brittle material. Preferably, the powder heating step STEP2
The powder quenching step STEP3 is repeated about 5 times. In addition, the powder heating step STEP of such multiple times
After the powder quenching step 2 and the powder quenching step STEP3, it was confirmed that the particles were discolored black when viewed through a microscope, and many cracks were generated.

Next, in the fine pulverizing step STEP4, a predetermined amount of particles having cracks are charged into the collecting means 40 as a powder.
The powder is stored in the powder storage chamber 41 through the outlet 42. At this time, the amount of particles stored in the powder storage chamber 41 is about half the volume of the powder storage chamber 41, preferably 25.
% To about 35%. By doing so, the particles can be carried on the high-pressure gas and smoothly circulated from the powder storage chamber 41 to the air-fuel mixture inflow chamber 30 and the finely pulverizing means 10. The fine pulverization step STEP4 will be described in detail. First, while controlling the pressure of the high pressure gas from the high pressure gas supply means 20, the pipeline 1
High-pressure inflow and injection into the air-fuel mixture inflow chamber 30 via 5. Then, the high-pressure gas flowing from the high-pressure gas supply means 20 into the mixture gas inflow chamber 30 flows into and injects at high pressure into the first flow passage 11a and the second flow passage 11b of the fine pulverization means 10 through the flow passage 35. To be done. After that, the high-pressure gas that has flowed into the first flow path 11a and the second flow path 11b of the finely pulverizing means 10 passes through the flow path 15 and the powder storage chamber 41 of the collecting means 40.
Injected and injected at high pressure. And the powder storage chamber 4
The high-pressure gas that has flowed into 1 is recirculated into the mixture gas inflow chamber 30 via the pipe 45 of the circulation means and the pressure adjusting means 50, and is injected and injected at high pressure. At this time, the particles (powder) stored in the powder storage chamber 41 are forcibly flown and injected into the pipe 45 by the high-pressure gas to form an air-fuel mixture with the high-pressure gas. It is injected and injected into the air-fuel mixture inflow chamber 30 via the means 50.

Then, the air-fuel mixture (high-pressure gas and particles on the high-pressure gas) flowing into the air-fuel mixture inflow chamber 30 is further mixed with the high-pressure gas continuously supplied from the high-pressure gas supply means 20, and finely pulverized means. Ten first and second flow paths 11a,
High-pressure inflow and injection into 11b. At this time, pressure control by the pressure adjusting means 50 is performed in the air-fuel mixture inflow chamber 30, and the first and second flow paths 11 a, 11 of the fine pulverizing means 10 are performed.
In b, the desired air-fuel mixture with a constant pressure is always particles (powder).
Flows in in a uniformly dispersed state. The air-fuel mixture that has flowed into the first and second flow paths 11a and 11b of the finely pulverizing means 10 flows into the powder storage chamber 41 at high pressure. Thus, in the circulation step STEP5, the air-fuel mixture inflow chamber 30 →
Flow channel 35 → first flow channel 11a of finely pulverizing means 10 → second flow channel 11b → flow channel 15 → powder storage chamber 41 → pipe line 45 → pressure adjusting means 40 → mixture gas inflow chamber 30 The circulation system is formed, and the air-fuel mixture repeatedly flows into the first and second flow paths 11 and 11b of the fine pulverizing means 10 at high pressure. That is,
The fine pulverization step STEP4 is repeated for the required time (the required number of times).

At this time, in the fine crushing means 10, the cutting blade 12
Have blade edges facing each other in the center of the first flow path 11a, so that particles (powder) in the air-fuel mixture flowing into the first and second flow paths 11 and 11b are at least the cutting blade 12 Finely pulverized due to collision energy with (especially blade edge 12x).
Further, at this time, since the particles in the air-fuel mixture have a large number of enlarged cracks, when colliding with the cutting edge 12x of the cutting blade 12, the cutting edge 12x enters the gap between the cracks to further expand the cracks. To do. As a result, the cracks of the particles become complete cracks, and each particle can be easily fractured and finely pulverized. Further, the particles that have passed through the cutting edge 12 ride on the circulation system of the air-fuel mixture as described above, and repeatedly pass through the cutting edge 12 many times. Therefore, the particles that have not collided with the cutting edge 12 and have not been finely crushed also collide with the cutting edge 12 while repeatedly passing through the cutting edge 12 and are finely pulverized. The particles that have collided with the cutting edge 12 and are finely pulverized further collide with the cutting edge 12 many times to be finely pulverized more finely. Thus, for example, when particles having a particle diameter of 10 μm are used as raw material particles, they can be easily finely pulverized (made into fine particles) to a particle diameter of about 1 μm. The cutting edge 12x of the cutting edge 12x
The smaller the radius of curvature of the tip, the greater the possibility that the cutting edge 12x will enter the cracks of the particles, and the finer the particle size (minimum particle diameter) of the finely pulverized particles.

The impact force required to break the particles made of a brittle material at the time of fine pulverization is related to the particle cracks, defect structure, crack propagation susceptibility, etc., and can be expressed by the following equation. σ = (2Er / D) 1/2

Here, E is the elastic modulus, r is the radius of the crack or the tip of the crack existing in the particles, and D is the particle size. After all, the larger the particles, the smaller the impact force required for fine grinding. On the other hand, as the particle size decreases during grinding,
The stress required to subsequently reduce the grain size increases.

Regarding the relative energy required for finely pulverizing the particles, starting from the initial particle size Di and ending with the final particle size Df
The energy W required to obtain is as follows from the empirical formula. W = g (Df-α-Di-a)

Here, g is fine particles, the cutting edges 12 and 11
2, a constant that depends on the design and manufacturing conditions of the finely pulverizing means 10. Also, the index α is usually between 1 and 2.

The pressure of the high-pressure gas and the air-fuel mixture flowing into the first flow passage 11a of the finely pulverizing means 10 is controlled by the air-fuel mixture inflow chamber 3
It depends on the inflow gas pressure from 0 to the first flow passage 11a of the fine pulverization means 10, the diameter of the flow passage 35 of the mixture gas inflow chamber 30, the diameter of the first flow passage 11a of the fine pulverization means 10, and the like. Also,
To finely pulverize the particles, the first channel 1 of the finely pulverizing means 10 is used.
It is preferable to increase the pressure of the air-fuel mixture flowing into 1a.
On the other hand, if the inflow pressure of the air-fuel mixture into the first flow path 11a is too high, the cutting edge 12x of the cutting blade 12 is likely to be chipped early. Therefore, in consideration of these points and the composition and physical properties of the raw material particles to be used, the inflow gas pressure from the air-fuel mixture inflow chamber 30 to the first flow passage 11a of the fine pulverizing means 10 and the flow passage of the air-fuel mixture inflow chamber 30 are considered. It is necessary to control the diameter of 35 and the diameter of the first channel 11a of the fine pulverizing means 10 to appropriate values.

When hydrogen gas (H2 gas) is used as the gas supplied from the high pressure gas supply means 20 in the fine pulverization step STEP4 and the circulation step STEP5,
Since hydrogen molecules have a very small diameter as a molecule (particle), they easily enter the crack (gap) of glass particles,
It can be expected to assist the fine grinding of glass particles. Further, due to the air-fuel mixture (high-pressure gas) injected at high pressure into the first flow path 11a of the finely pulverizing means 10, the cutting edge 12x of the cutting edge 12 is formed.
It is conceivable that a shock wave extending in a conical shape from the rear to the downstream (downstream) of the flow path is generated. Therefore, it can be expected that the shock waves also assist the fine pulverization of the particles.

Fine grinding step STEP4 and circulation step STE
After repeating P5 for a predetermined time (predetermined number of times), next, in a collecting step STEP6, the fine particles that have passed through the first and second flow paths 11a and 11b of the fine crushing means 10 and are sufficiently finely divided are The powder is collected in the powder storage chamber 41 communicating with the first and second flow paths 11a and 11b. That is, by stopping the supply of the high-pressure gas from the high-pressure gas supply means 20, the pressure in the air-fuel mixture inflow chamber 30 suddenly decreases, the circulation system of the air-fuel mixture disappears, and the fine particles (fine powder) in the air-fuel mixture are removed. The body) naturally accumulates in the powder storage chamber 41 and is collected and stored. And
The powder loading / unloading port 42 of the collecting means 40 is opened, and the fine powder in the powder storage chamber 41 is taken out to be used as a fine powder (fine particle) material for desired applications such as molding. If necessary, in the classification step STEP7, the fine powder taken out from the powder storage chamber 41 is classified using a known classification means,
Alternatively, impurities may be removed in a sorting step (not shown).

[Embodiment 2] FIG. 4 is a sectional view schematically showing an essential part of a fine pulverizing means of an apparatus for producing fine particles made of a brittle material according to Embodiment 2 of the present invention.

In the apparatus for producing fine particles according to the first embodiment, as the cutting blade 12 of the finely pulverizing means 10, one having only one side surface inclined to be the blade surface 12a is used. In the apparatus for producing fine particles, as shown in FIG. 4, as the cutting blade 112 of the finely pulverizing means 110, both side surfaces are inclined to form blade surfaces 112a and 112b, and the blade tip 112x is formed at the tip between the both blade surfaces 112a and 112b. Is used. Further, in the apparatus for producing fine particles according to the second embodiment, the downstream end of the flow path 55 in the pressure adjusting means 50 communicating with the downstream end of the conduit 45 is the first of the fine pulverizing means 110.
Is connected to the upstream side of the flow path 11a (for example, the conduit 35) in a tilted state. That is, in the apparatus for producing fine particles according to the second embodiment, the finely pulverizing means 110 introduces the air-fuel mixture into the first channel 11a in a state of being inclined with respect to the axial direction of the first channel 11a. .

Also in the case of the second embodiment, the same operation and effect as those of the first embodiment are exhibited. Furthermore, since the cutting blade 112 is composed of a type having a pair of blade surfaces 112a and 112b, not only the cutting edge 112x but also the cutting blade 112 itself faces the center of the downstream end of the first flow passage 11a of the housing 11. Can be arranged to be located. As a result, the cutting edge 112 is removed from the first flow path 11 a of the housing 11.
It is possible to further improve the flow state of the air-fuel mixture that passes through the second channel 11b and passes through. Also, the fine crushing means 110
However, since the air-fuel mixture is introduced into the first flow passage 11a in a state of being inclined with respect to the axial direction of the first flow passage 11a, the high-pressure gas supply means 20 flowing through the flow passage 35 of the air-fuel mixture inlet chamber 30 It is possible to smoothly mix the high pressure gas from the flow passage 55 of the pressure adjusting means 50 with the high pressure gas.

[Embodiment 3] FIG. 5 is a block diagram schematically showing main components of an apparatus for producing fine particles made of a brittle material according to Embodiment 3 of the present invention.

The apparatus for producing fine particles according to the first embodiment is
Raw material particles having cracks generated through a plurality of heating steps and quenching steps are stored in advance in the collection means 40, and high pressure gas is supplied to the collection means 40 from the high pressure gas supply means 20 through the mixture gas inflow chamber 30. The particles are circulated and circulated in the fine pulverizing means 10 and finely pulverized by the cutting blade 12. That is, the collecting means 40 has a function of storing the raw material particles and supplying the raw material particles to the pulverizing means 10 by the inflow of the high-pressure gas, in addition to the original purpose [collecting]. On the other hand, in the apparatus for producing fine particles according to the third embodiment, raw material particles having cracks generated through a plurality of heating steps and quenching steps are supplied from the separately prepared powder supplying means 200 to the air-fuel mixture preparing / injecting means 210. At the same time, the high pressure gas is supplied from the high pressure gas supply means 20 to the mixture preparation / injection means 210. Then, the air-fuel mixture preparing / injecting means 210 disperses the raw material particles in the high-pressure gas to prepare an air-fuel mixture, and the air-fuel mixture is injected at high pressure into the fine pulverizing means 10 and finely pulverized by the cutting blade 12. Further, the air-fuel mixture that has passed through the fine pulverization means 10 is
The mixture circulating means 220 circulates and circulates the finely pulverizing means 10 through a pipe or a flow path 225, and finely pulverizes again by the cutting blade 12. Then, the finely pulverized fine particles are supplied from the air-fuel mixture circulation means 220 to the conduit or flow path 23.
Through the fine particle collecting / classifying means 230,
Be classified. That is, the particulate collection / classification means 230 is used only for its original purpose (collection / classification).

[Other Example] In the first or second embodiment, the collecting means 40 includes a pressure reducing means for maintaining the inside of the powder storage chamber 41 in a substantially vacuum state. By maintaining the inside of the powder storage chamber 41 in a substantially vacuum state in this state, the introduction speed of the air-fuel mixture introduced from the high-pressure gas supply means 20 into the first flow passage 11a of the fine pulverization means 10 is increased, Cutting edge 12, 112 cutting edge 12x, 1
It is also possible to increase the impact energy on 12x.

Further, in each of the above embodiments, the cutting edge 1
2, 112 are arranged along the first and / or second flow paths 11a, 11b of the fine pulverizing means 10 in a plurality of stages at a predetermined interval from the upstream side to the downstream side, and particles are generated with one passage of the air-fuel mixture. You may make it pulverize several times continuously. Alternatively, a plurality of cutting blades 12 and 112 may be arranged at the same position in the first and / or second flow paths 11a and 11b of the fine pulverizing means 10. In either case, the amount of finely pulverizable particles can be increased with one passage of the air-fuel mixture.

The finely pulverizing means and the finely pulverizing step of the present invention may be those that mechanically finely pulverize the particles having the cracks. Therefore, the finely pulverizing means and the finely pulverizing step of the present invention can be configured so that the raw material particles having cracks caused by repeated heating and rapid cooling are subjected to mechanical impact by a dry pulverizer or the like to cause brittle fracture. For example,
The fine particles can also be formed by using a mechanical crushing means such as an ordinary ball mill or roller mill.

[Use] The fine particles produced by the apparatus and method for producing fine particles made of a brittle material according to the present invention can be applied to various powder application techniques. That is, generally, the powder is an aggregate of solid particles and is one of the material forms that are widely used in a wide range of industrial fields.
The properties of powders are the characteristics peculiar to the particles that make up the powders,
It is determined by both secondary properties that depend on particle size. And as the particles become finer, for example,
The powder properties such as reaction, dissolution and extraction are improved. Therefore, making the particle size fine leads to higher performance and higher functionality of the powder. Therefore, the fine particles having a fine particle size obtained by the production apparatus and the production method of the present invention can be suitably used, for example, in molding using powder as a raw material, and in this case, the solid density is increased and the fineness is increased. A molded body can be obtained. In the molding operation, fine powder is put into a mold, heated and melted, and molded, but fine particles having a fine particle size obtained by the manufacturing apparatus and the manufacturing method of the present invention can be easily molded in one shot. .

Further, it is also possible to manufacture a plurality of kinds of fine particles having a fine particle size by using the manufacturing apparatus and the manufacturing method of the present invention, and mix and use them. In this case, the materials are mixed at the molecular level to form a mixture. can do. As a result, the physical properties of the molded body and the like can be easily changed by appropriately selecting the necessary materials. That is, the chemical composition can be arbitrarily changed by a physical method of changing the material mixing ratio, and thus the physical properties can be arbitrarily changed. Further, by using fine particles having a fine particle size obtained by the production apparatus and the production method of the present invention, a solid having a high density can be formed, and the cutting edges 12, 112 of the fine pulverizing means 10 are formed by this solid. Then, sharper cutting edges 12x and 112x can be formed. Further, the fine particles having a fine particle size obtained by the production apparatus and the production method of the present invention can be applied to a low temperature crystallization technique or can be used as a glass for solidifying a waste radioactive substance.

In the fine particle size region, reaggregated particles may be present as secondary particles. When a large amount of such aggregated particles are contained in the powder, the properties of the powder are determined by the behavior of the aggregated particles. And
No matter how fine the primary particles are, the result will not be unique to the high performance of the powder. Therefore, the disintegration treatment of aggregated particles (secondary particles) is effective.
A general crushing device (dry crusher, wet crusher) can be used for the crushing treatment.

[0054]

According to the method for producing fine particles made of brittle material according to the first to third aspects, fine particles having a fine particle size can be easily produced. That is, by adopting dry pulverization, it is possible to inexpensively produce fine particles having a fine particle size with a relatively simple structure.

In the method for producing fine particles made of a brittle material according to claim 4, glass particles are further used as the particles made of the brittle material, and the glass particles are heated at a temperature lower than the glass transition temperature in the heating step. It is possible to efficiently generate cracks in the glass particles.

In the method for producing fine particles of a brittle material according to a fifth aspect, the mixture is introduced into the flow channel in a state of being inclined with respect to the axial direction of the flow channel in the fine pulverization step. Air can be smoothly introduced into the flow path.

In the method for producing fine particles of brittle material according to the sixth aspect, since the introduction speed of the air-fuel mixture introduced into the flow path can be further increased, the fine pulverization by the cutting edge in the fine pulverization step can be further performed. It can be done efficiently.

According to the apparatus for producing fine particles made of the brittle material according to claims 7 to 9, fine particles having a fine particle size can be easily produced. That is, by adopting dry pulverization, it is possible to inexpensively produce fine particles having a fine particle size with a relatively simple structure.

In the apparatus for producing fine particles made of a brittle material according to claim 10, glass particles are further used as the particles made of the brittle material, and the glass particles are heated by a heating means at a temperature lower than the glass transition temperature. It is possible to efficiently generate cracks in the glass particles.

According to the eleventh aspect of the apparatus for producing fine particles made of a brittle material, further, since the air-fuel mixture is introduced into the channel in a state of being inclined with respect to the axial direction of the channel of the fine pulverizing means, the air-fuel mixture is mixed. Can be smoothly introduced into the flow path.

In the apparatus for producing fine particles of brittle material according to the twelfth aspect of the invention, since the introduction speed of the air-fuel mixture introduced into the flow path can be further increased, the fine pulverization by the cutting edge of the fine pulverization means is more effective. It can be done efficiently.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing main constituent elements of an apparatus for producing fine particles made of a brittle material according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically showing a main part of a fine pulverizing means of the apparatus for producing fine particles made of a brittle material according to the first embodiment of the present invention.

FIG. 3 is a flow chart showing steps of a method for producing fine particles made of a brittle material according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a main part of a fine pulverizing means of an apparatus for producing fine particles made of a brittle material according to a second embodiment of the present invention.

FIG. 5 is a block diagram schematically showing main components of an apparatus for producing fine particles made of a brittle material according to a third embodiment of the present invention.

[Explanation of symbols]

10, 110: Fine pulverizing means, 11a: First flow path, 1
2, 112: Cutting blade 40: Collection means, 41: Powder storage chamber, 45: Pipe line (circulation means) 50: Pressure adjusting means (circulation means)

Claims (12)

[Claims] 1. A heating step of heating particles made of a brittle material, a rapid cooling step of rapidly cooling the heated particles to generate cracks in each particle, and a fine grinding step of mechanically pulverizing the particles having the cracks. A method for producing fine particles made of a brittle material, which comprises a crushing step. 2. A heating step of heating particles made of a brittle material at a temperature lower than a softening temperature, a quenching step of rapidly cooling the heated particles to generate cracks in each particle, and particles having the cracks in a gas. Is dispersed at high pressure into a flow path in which the cutting blades are arranged to face each other and is circulated by circulating in the flow path, and at least the particles having the cracks are finely pulverized by collision energy with the cutting blades. A method for producing fine particles made of a brittle material, which comprises a fine pulverization step. 3. A heating step of heating particles made of a brittle material at a temperature lower than a softening temperature, a rapid cooling step of rapidly cooling the heated particles to generate cracks in each particle, and a high pressure gas supply means. A mixture of particles having the cracks dispersed in a gas is sprayed at a high pressure into a flow path in which the cutting blades are opposed to each other, so that the particles having the cracks are finely pulverized by collision energy with at least the cutting blades. A finely pulverizing step, a circulating step in which the particles are circulated by circulating them back into the flow channel, and a finely pulverizing step is repeated; and a finely pulverized particle that repeatedly passes through the flow channel is communicated with the flow channel. A method for producing fine particles made of a brittle material, comprising a collecting step of collecting in a storage chamber. 4. The brittleness according to claim 2, wherein the particles made of the brittle material are glass particles, and the glass particles are heated at a temperature lower than the glass transition temperature in the heating step. A method for producing fine particles made of a material. 5. The air-fuel mixture is introduced into the flow channel in a state of being inclined with respect to the axial direction of the flow channel in the finely pulverizing step.
A method for producing fine particles comprising the brittle material according to the item. 6. The inside of the storage chamber is maintained in a substantially vacuum state, and an introduction speed of an air-fuel mixture introduced from the high-pressure gas supply means to the flow path is set in the fine pulverization step, the collection step and the circulation step. The method for producing fine particles made of a brittle material according to any one of claims 2 to 5, wherein the number is increased. 7. A heating means for heating particles made of a brittle material, a quenching means for rapidly cooling the heated particles to generate cracks in the respective particles, and a finely mechanically crushed particle having the cracks. An apparatus for producing fine particles made of a brittle material, comprising: a crushing unit. 8. A heating means for heating particles made of a brittle material at a temperature lower than the softening temperature, a rapid cooling means for rapidly cooling the heated particles to generate cracks in each particle, and particles having the cracks in a gas. Is dispersed at high pressure into a flow path in which the cutting blades are arranged to face each other and is circulated by circulating in the flow path, and at least the particles having the cracks are finely pulverized by collision energy with the cutting blades. An apparatus for producing fine particles made of a brittle material, comprising: a finely pulverizing means. 9. A heating means for heating particles made of a brittle material at a temperature lower than a softening temperature, a quenching means for rapidly cooling the heated particles to generate cracks in each particle, and a high pressure gas supply means A mixture of particles having the cracks dispersed in a gas is sprayed at a high pressure into a flow path in which the cutting blades are opposed to each other, so that the particles having the cracks are finely pulverized by collision energy with at least the cutting blades. A fine pulverizing unit, a circulating unit that circulates the particles by circulating them back into the flow channel, and repeats the fine pulverizing step, and a storage chamber that communicates with the flow channel, and repeatedly passes through the flow channel to generate fine particles. An apparatus for producing fine particles made of a brittle material, comprising: a collection unit configured to collect the crushed particles in the storage chamber. 10. The particles made of the brittle material are glass particles, and the heating means heats the glass particles at a temperature lower than the glass transition temperature.
Or an apparatus for producing fine particles made of the brittle material according to 9. 11. The fine grinding means introduces the air-fuel mixture into the flow channel in a state of being inclined with respect to the axial direction of the flow channel. Equipment for producing fine particles of brittle materials. 12. The storage chamber includes decompression means for maintaining the inside of the storage chamber in a substantially vacuum state. By maintaining the inside of the storage chamber in a substantially vacuum state by the decompression means, the flow from the high pressure gas supply means is reduced. The device for producing fine particles made of a brittle material according to any one of claims 8 to 11, wherein the introduction speed of the air-fuel mixture introduced into the passage is increased.