JP3470908B2 - Dispersion nozzle, method for supplying solid fine particles using the same, and method for producing spheroidized particles - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention has a particle size of 0.5 to 0.5.
Dispersion nozzle for injecting 100 μm solid fine particles of metal, non-metal, inorganic compound, metal compound or the like with gas in a two-phase flow and jetting them in a uniformly dispersed state, and method of supplying solid fine particles using the same And a method for producing spherical particles.

[0002]

2. Description of the Related Art In recent years, solid fine particles of metal, non-metal, inorganic or organic compound, metal compound, etc. having a size of submicron to several hundreds of micron are manufactured by a wet method or a dry method, and an injection molding material using the solid particles as a raw material. , Sintered materials, conductive pastes, fillers, filters, sealing materials, spacers, additives, catalysts, etc. are produced. In these application fields, along with the improvement in quality, there has been a demand for high spheroidization as well as miniaturization.

For example, various methods for improving the spheroidizing of solid fine particles have been attempted in recent years. For example, the gas or water atomizing method (spraying method) disclosed in Japanese Patent Laid-Open No. 11704/1990 and the Japanese Patent Laid-Open Publication No. Sho. No. 63-230807, the rotary atomizing method disclosed in JP-A-1-234506, and the JP-A No. 63-58799.
The plasma arc method and the like disclosed in the publication are proposed.

The plasma arc method disclosed in Japanese Patent Laid-Open No. 63-58799 discloses a method in which amorphous particles are inserted into an arc plasma flame and granulated.

On the other hand, the applicant of the present invention also discloses the above-mentioned Japanese Patent Laid-Open No.
Japanese Patent Publication No. 246104 discloses a method of supplying a treatment substance to an end region of a generated plasma flame together with an inert gas in a countercurrent direction to the flow direction of the plasma flame.

Further, in Japanese Patent Application No. 4-178352, the treatment substance is directed forward from the plasma flame axis in the plasma gas flow direction to the tail flame region outside the high frequency induction coil placement region in the generated plasma flame. It is proposed that the gas is supplied together with the active gas or the inert gas toward the plasma flame axis from a range excluding the ± 45 ° range.

[0007]

As in the above example, in the method of supplying the treatment substance together with the inert gas to the generated plasma flame, the solid fine particles having strong cohesiveness and aggregation property are treated as follows. Whether or not the desired dispersion state can be supplied into the plasma flame is an important key to the quality of the obtained spheroidized particles.

Conventionally, as a method of supplying the treatment substance in a dispersed state, for example, there is a method of sieving it before supplying it into the plasma flame or dispersing it by changing the amount of carrier gas for transportation.

However, in the above-mentioned method, the finer the solid particles, the stronger the cohesiveness and the cohesiveness. Therefore, the solid fine particles are dispersed by a sieve and then agglomerated again during transportation. Further, in the case of only changing the amount of carrier gas, there are problems such as insufficient dispersion effect. At present, it is difficult to disperse and supply fine particles having a size of submicron to several hundreds of microns, which hinders the post-process.

On the other hand, not only for spheroidizing the solid fine particles, but also for drying, melting, burning, evaporation treatment, etc., supplying the solid fine particles in a dispersed state is an important subject for improving work efficiency and quality. Has become.

Therefore, the main object of the present invention is to spray and supply solid fine particles such as metal, non-metal, inorganic or organic compound, or metal compound having a particle diameter of 0.5 to 100 μm in a uniformly dispersed state. To provide a dispersion nozzle suitable for the above.

[0012]

SUMMARY OF THE INVENTION The above-mentioned problems are solved by forming a flow passage having a diameter larger than that of a general portion flow passage reaching the nozzle in a concentric manner over a predetermined range from the nozzle tip. At the same time, the problem can be solved by disposing an impact wall member for colliding with the solid fine particles that are conveyed while being separated from each other in the diameter-expanding flow path and at the outlet of the general part flow path. In this case, the diameter of the barrier wall member is 1.0 to the diameter of the flow path of the general portion.
It is 3.0 times, and the flow path cross-sectional area of the diameter-expanding flow path excluding the impact wall member is 2.0 to 6.0 times the flow path cross-sectional area of the general portion, which is optimal for achieving a high spherical shape. .

In supplying the solid fine particles, the solid fine particles having a particle diameter of 0.5 to 100 μm are targeted, and the solid fine particles in the two-phase flow are dispersed in the two-phase flow with the active gas or the inert gas. In the nozzle, the colliding wall member is collided and dispersed, and the kinetic energy is attenuated to be sprayed and supplied.

A high-frequency magnetic field is excited by a high-frequency induction coil, a plasma gas is supplied into the high-frequency magnetic field to inductively generate a high-frequency plasma flame, and a high-pressure plasma flame is generated in the high-frequency plasma flame by a supply pipe. When the treatment substance is supplied to obtain spheroidized particles, the dispersion nozzle according to claim 1 is attached to the tip of the supply pipe, and solid fine particles having a particle diameter of 0.5 to 100 μm are added together with an active gas or an inert gas. The solid fine particles are conveyed in a two-phase flow state, collide with the impingement wall member in the dispersion nozzle to disperse the solid fine particles, and the kinetic energy is attenuated to be sprayed and supplied.

[0015]

When solid particles such as a metal, non-metal, inorganic or organic compound, or metal compound having an individual particle diameter of 0.5 to 100 μm are conveyed by an active gas or an inert gas in a two-phase flow, the solid particles are solid particles. Has a specific gravity of 1000
Since it is ~ 10,000 times larger, the kinetic energy held by solid fine particles is relatively large when the solid fine particles are carried on a gas.

Therefore, in the present invention, a flow passage having a diameter larger than the flow passage diameter of the general portion up to the nozzle is formed concentrically in the nozzle over a predetermined range from the tip of the nozzle. When the gas in the two-phase flow reaches the diameter-increasing flow passage through the general-portion flow passage, the flow velocity is rapidly reduced and diffuses according to the law of constant flow rate. On the other hand, the solid fine particles have a very large kinetic energy, and therefore, even if the cross-sectional area of the flow path becomes large, they travel straight as they are without slowing down. . Then, the solid particles in the agglomerated state are disintegrated and dispersed in the diameter-expanding flow path (the space between the general-portion flow path outlet and the abutment wall member), and the kinetic energy is attenuated into the decelerated gas. It gets on and is released in a dispersed state.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on specific examples shown in the drawings. FIG. 1 is a vertical sectional view of a dispersion nozzle N according to the present invention, and FIG. 2 is a view of the dispersion nozzle N seen from the front.

The dispersion nozzle N is composed of a nozzle body 1 screwed to the tip of the conduit 6, and a dispersion cover 2 screwed to the tip side of the nozzle body 1. A dispersion pocket space P having a relationship of concentrically expanding with respect to the flow path of the conduit 6 is formed in the tip portion of the nozzle body 1, and in the dispersion pocket space P, the dispersion cover 2 is formed.
The solid fine particles conveyed in the relationship with the wall member 2a integrally fixed to the above are crushed and dispersed (details will be described later).

The dispersion cover 2 has an outer ring member 2b.
An inner wall of the conduit 6 is provided with an impact wall member 2a located on the same axis as the flow axis of the conduit 6, and the outer ring member 2b and the impact wall member 2a are connected by four connecting members 2c, 2c. ing. An injection port R for injecting solid fine particles is formed between the outer ring member 2b and the abutting wall member 2a. The outline of the injection port R coincides with the outline of the dispersion pocket space P formed in the main body nozzle 1.
In addition, the connecting member 2c for fixing and supporting the abutment wall member 2a is
It is not necessary to provide four in the cross direction, but may be two in the vertical direction or three in the radial direction.

The facing surface S of the abutment wall member 2a facing the general portion flow path outlet 1a of the conduit 6 has a conical shape,
The apex angle β of this cone is in the range of approximately 90 to 270 °. Further, the shape of the facing surface S of the abutting wall member 2a may be a plane shown in FIG. 3, a split spherical surface shown in FIG. 4, or a spherical surface shown in FIG. The shape is not limited at all.

General portion flow path R ₁ leading to the nozzle N
The ratio d / d ₁ diameter d ₁ between the diameter d of the barrier wall means member 2a
Is in the range of 1.0 to 3.0, preferably 1.2 to 2.0. In the two-phase flow conveyed by the conduit 6, the solid fine particles may not be in a homogeneous state in the pipe, and the solid fine particles may be conveyed in a non-uniform state due to the agglomeration state, the gas flow velocity or the specific gravity and shape of the solid fine particles. There are many.
In this case, when d / d ₁ <1, the solid fine particles conveyed along the tube wall do not collide with the collision wall member 2a, that is, the solid particles are aggregated or drifted without undergoing energy attenuation and are in an inhomogeneous state. Thus, it is injected from the injection port R.
Further, the solid fine particles are expanded in the dispersion pocket space P, and at the same time the distribution area thereof is d ₁ due to the decrease of the gas flow velocity and the own weight.
Although it tends to spread more, it is sufficient if d / d ₁ ≦ 3.0, and even if it is larger than this, the pressure loss only increases, and the nozzle shape becomes unnecessarily large and the cost increases. There is not much merit. Further, the ratio A of the flow passage area A ₁ of the general portion flow passage R _{1 and} the area A of the injection port R
/ A ₁ is 2.0 to 6.0, preferably 2.5 to 5.0.
It is better to set the range. The area of the injection port R defines the flow velocity at which the two-phase flow is discharged from the dispersion nozzle, and is selected so that the solid fine particles crushed and dispersed in the nozzle are uniformly conveyed. There is a need. Further, it is a factor that is influenced by physical properties of fine particles such as specific gravity and shape of solid fine particles. In the case of A / A ₁ <2.0, not only the dispersed substance re-aggregates but also
The efficiency in obtaining the spheroidized particles decreases. A / A ₁ > 6.
In the case of 0, the flow velocity of the two-phase flow at the injection port R is unnecessarily increased, which not only increases the pressure loss but also increases the wear of the nozzle. In addition, the efficiency in obtaining the spheroidized particles decreases. Although a matter derived by calculation from the dimensional ratio of the above, the ratio D / d ₁ diameter d ₁ of the general part flow path R ₁ and the inner diameter D of the dispersed pocket space P is 1.7
The range is 3.9, preferably 1.9 to 3.0. Furthermore, a suitable range of the separation distance L between the general portion flow path outlet 1a and the facing surface S of the abutting wall member 2a is d _{1 to} 4d ₁ , preferably 1.5d _{1 to} 3d ₁ . On the other hand, in terms of the relationship with the flow rate of the transported solid fine particles, the higher the transportation speed, the higher the reduction rate needs to be. Therefore, it is qualitatively preferable to increase D / d ₁ and A / A ₁ .

Incidentally, the nozzle body 1 and the dispersion cover 2
In addition to metal such as gun metal and stainless steel, wear resistant material such as ceramic is preferably used for a part or all of the nozzle. Further, when contamination by fine particles to be treated poses a problem, a material of the same quality as the fine particles is used.

In the dispersion nozzle N constructed as described above, a part of the solid fine particles is conveyed in the conduit 6 together with the active or inert gas in a state of being aggregated or collected and introduced into the dispersion nozzle N. Then, when the gas in the two-phase flow is introduced into the dispersion pocket space P in the wide nozzle body 1 from the narrow conduit 6, A (flow passage area) × v
(Velocity) = Q (Flow rate), according to a certain law, as a result of the widening of the flow passage area, the flow velocity is sharply reduced and diffused in the radial direction mainly as indicated by arrow 4, and then the jetting of the dispersion cover 2 is performed. It is discharged from the mouth R to the outside.

On the other hand, regarding the solid fine particles in the two-phase flow,
Since its kinetic energy is 1000 to 10000 times as large as that of gas, even if the solid fine particles are introduced from the conduit 6 into the dispersion pocket space P in the nozzle body 1, they will not diffuse rapidly like gas and will not collide. It directly collides with the facing surface S of the member 2a. The agglomerated or aggregated solid fine particles collide with the facing surface S while keeping the flow velocity in the conduit 6 as it is, so that the kinetic energy is rapidly lost and at the same time, the aggregated or aggregated state is released by the collision energy. It is crushed and scattered in all directions as shown by arrow 5. The scattered solid fine particles ride on the diffused gas, are decelerated, and are discharged outward from the injection port R in a dispersed state.

Example 1 Hereinafter, the effects of the present invention will be clarified by examples. Figure 1
In the case of using the dispersion nozzle N of the present invention shown in FIG. 1 to carry out dispersion spraying of fine silver particles by argon gas, the fine silver particles of argon are directly supplied from the tube mouth without the nozzle N of the present invention under the same transfer conditions. The state of dispersion was visually observed in the case of carrying by gas and dispersed and sprayed. The geometry of the dispersion nozzle N used is the flow passage area A ₁ of the conduit 6;
07mm ² , diameter d of the abutment wall member 2a; 5mm, apex angle 180 °,
Area of emission port R of dispersion nozzle A; 23.3 mm ² , A / A ₁ =
3.3. Dispersion atomization was carried out by using fine particles of silver (melting point 961 ° C, purity 99.95%, average particle size 0.6 in argon gas 5 l / min.
Aggregate of porous amorphous particles having an apparent specific gravity of 0.88 g / cm ³ ) is continuously supplied at 2 g / min, and silver fine particles are pneumatically transported and jetted from a dispersion nozzle N or a normal nozzle. Regarding the dispersed spray state, FIG. 6 shows the case of the dispersion nozzle N according to the present invention, and FIG. 7 shows the case of spraying from a pipe port without using the nozzle of the present invention. As is clear from the figure, when the dispersion nozzle N of the present invention in FIG. 5 is used, the dispersion state is in the range of 0 mm to 200 mm, particularly 100 mm or more, especially in the case of the normal nozzle. It is found that the fine particles are linearly jetted in the range of the stall distance from the nozzle up to 200 mm.

[Embodiment 2] Next, in the high frequency plasma reactor shown in FIG. 8, the embodiment 1 is carried out in the plasma flame F generated by actually attaching the dispersion nozzle N of the present invention to the tip of the supply pipe (conduit) 8.
The spheroidizing treatment was performed for each of the case where the silver fine particles used in 1) were supplied and the case where the silver fine particles were supplied by the normal nozzle, and the spheroidization rate was measured and the nozzle condition was observed. Dispersion nozzle N is d / d ₁ (impact wall member diameter /
Four types were prepared with different diameters of the flow path of the general part) and A / A ₁ (area of the injection port / area of the flow path of the general part). Further, the supply condition of the treatment substance is the same as in Example 1 such that the argon gas is 5 l / l.
Fine silver particles were continuously fed at 2 g / min during min.

[0027]

[Table 1]

From Table 1, first, the dispersion nozzle N according to the present invention is shown.
It was found that the spheroidization rate was markedly improved in the case of using No. 1 as compared with the case of using a normal nozzle. Even when the dispersion nozzle N is used, d /
It was found that d ₁ and A / A ₁ cause a large variation in the spheroidization rate.

In the case of a normal nozzle, fine silver particles adhered and solidified in the vicinity of the nozzle, making continuous stabilization impossible. This is because the particles were ejected without being crushed while retaining high kinetic energy, and thus penetrated through the plasma flame F, collided with the periphery of the nozzle on the opposite side, and adhered and solidified.

[0030]

As described above in detail, according to the present invention, it becomes possible to supply solid fine particles which are easily aggregated and aggregated in a state in which they are uniformly dispersed. Therefore, for example, spherical particles produced by a plasma generator are provided. In the production of, the product can be obtained with a high spheroidization rate.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a dispersion nozzle according to the present invention.

FIG. 2 is a front view of a dispersion nozzle according to the present invention.

FIG. 3 is a vertical cross-sectional view of another dispersion nozzle.

FIG. 4 is a vertical cross-sectional view of another dispersion nozzle.

FIG. 5 is a vertical cross-sectional view of another dispersion nozzle.

FIG. 6 is a photograph of a spraying state by the dispersion nozzle of the present invention.

FIG. 7 is a photograph of a spraying state using a normal nozzle.

8 is a vertical cross-sectional view of the plasma generator used in Example 2. FIG.

[Explanation of symbols]

1 ... Nozzle body, 2 ... Dispersion cover, 2a ... Impact wall member,
6 ... conduit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-59408 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B01J 8/00 B05B 1/00 B05B 7 / 14

Claims (2)

(57) [Claims] 1. A high-frequency magnetic field is excited by a high-frequency induction coil, a plasma gas is supplied into the high-frequency magnetic field to inductively generate a high-frequency plasma flame, and an active gas or an inert gas is supplied into the high-frequency plasma flame by a supply pipe. It is used in a method of supplying spheroidized particles by supplying a treatment substance together with gas, and is attached to the tip of the supply pipe and has a particle diameter of 0.5 to 10
A dispersion nozzle for transporting 0 μm solid fine particles in a two-phase flow state together with an active gas or an inert gas, and supplying the solid fine particles in the two-phase flow into the high-frequency plasma flame. A flow passage having a diameter larger than that of the flow passage of the general portion up to the nozzle is formed concentrically over a predetermined range from the tip of the nozzle, and an outlet portion of the flow passage of the general portion within the diameter passage. Is provided with an impact wall member for colliding with the solid fine particles that are conveyed separately from each other, and the diameter of the impact wall member is 1.0 of the diameter of the flow path of the general portion.
˜3.0 times, the flow path cross-sectional area of the expanded diameter flow path excluding the impact wall member is 2.0 to 6.0 times the general part flow path cross-sectional area, and moreover, the outlet part of the general flow path. And a facing distance between the collision member and the facing surface of the collision member is 1 to 4 times the diameter of the general flow path. 2. A high frequency magnetic field is excited by a high frequency induction coil, a plasma gas is supplied into the high frequency magnetic field to inductively generate a high frequency plasma flame, and an active gas or an inert gas is supplied into the high frequency plasma flame by a supply pipe. In the method of supplying a treatment substance together with a gas to obtain spheroidized particles, at the tip of the supply pipe; in a nozzle, concentrically a flow path having a diameter larger than a flow path diameter of a general portion leading to the nozzle is provided. Formed over a predetermined range from the tip of the nozzle, and provided with an impact wall member for colliding with the solid fine particles that are conveyed while being separated in the diameter-expanding flow path to the outlet of the general part flow path, In addition, the diameter of the impingement wall member is 1.0 to 3.0 times the diameter of the general portion passage, and the passage cross-sectional area of the expanded diameter passage excluding the impingement wall member is 2 times the passage portion of the general portion. .0 to 6.0 times, Also, the separation distance between the outlet of the general flow channel and the facing surface of the collision member is a dispersion nozzle having a diameter 1 to 4 times the diameter of the general flow channel, and the particles are introduced from the supply pipe into the high-frequency plasma frame. Solid fine particles having a diameter of 0.5 to 100 μm were conveyed together with an active gas or an inert gas in a two-phase flow state, and the solid fine particles were collided with the collision wall member in the dispersion nozzle to disperse the kinetic energy. A method for producing spheroidized particles, which comprises supplying by spraying in a state.