JP3246446B2 - Centrifugal disk spraying device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal disk spraying device for producing metal powder directly from molten metal, and more particularly to a centrifugal disk spraying device capable of increasing the yield without changing the external ratio of the powder. It is.

[0002]

2. Description of the Related Art Conventionally, a gas atomizing method (hereinafter, referred to as a GAT method) or a centrifugal disk spraying method (hereinafter, referred to as a CA method) is mainly used as a method of directly pulverizing a molten metal without mechanical processing. ) Is well known.

[0003] Among the above powdering methods, the GAT method is, for example, 4
A powder is obtained by directly blowing a high-pressure gas of up to 6 kgf / cm ² onto the melt and scattering it in a mist. However, since the GAT method consumes a large amount of gas, it is difficult to use an expensive inert gas or the like. For this reason, ordinary compressed air is used as a raw material from a metal material that does not pose a problem of powder oxidation. Often done using.

Therefore, the chamber for scattering the powder does not need to have a hermetic structure, and in order to collect the powder and prevent contamination, the melt is usually dropped or the high-pressure gas is blown in the atmosphere. At this time, a method of scattering the dispersed powder into the chamber is used.

In the CA method, molten metal is dropped on a central portion of the surface of a disk rotating at a high speed in a chamber, and the melt dropped by the centrifugal force of the rotating disk is dispersed / sprayed and blown into a space. Then, the powder is obtained by cooling and solidifying. Normally, in this method, the inside of the chamber is controlled to a predetermined gas concentration in advance, and only a small amount of gas is used for adjusting the gas concentration during production.

[0006]

However, the aforementioned GAT
According to the method, in the case of atomization in the horizontal direction, the scattering distance of the powder reaches 5 to 7 m, so enormous cost and labor are required to seal this space and properly control the gas concentration. Met.

[0007] Also in the CA method, the flying distance of the powder extends to a radius of 3 to 4 m. For this reason, if there is not enough space for scattering, the powder scattered from the disk surface collides with the inner wall of the chamber before it completely cools and solidifies, causing problems such as sticking and deformation of particles. Occurred. As described above, when a large amount of powder sticking due to collision occurs, the yield decreases, and the quality and function deteriorate due to deformation.

Accordingly, in order to sufficiently maintain the quality and function of the obtained powder while sufficiently securing the yield of the powder, a large chamber device (hereinafter referred to as C) having a diameter of 6 to 8 m is required.
A device is required. However, in such a large-sized device, since the installation space, the cost of the device itself, the amount of gas used, and the like are all enormous, the produced metal powder is expensive. It becomes something.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks of the conventional apparatus, and to reduce the size of the CA apparatus, reduce the initial cost of the apparatus, and reduce the yield of powder. It is an object of the present invention to provide a centrifugal disk spraying device capable of reducing the cost of a product by increasing the cost. It is to realize a simple alkaline manganese battery.

[0010]

According to the first aspect of the present invention, a molten metal (4) is dropped on a rotating disk (3) inside a chamber (1), and the molten metal is dropped by centrifugal force. Metal powder (8) by scattering metal (4)
In the centrifugal disk spraying device for producing the above, a blowing device (11) for generating an air flow in the inner circumferential direction of the chamber (1) by high-pressure gas at a position where the metal powder (8) scatters inside the chamber (1). Are arranged along the inner circumferential direction of the chamber (1).

According to the present invention, the blowing device (11) is arranged at an equal angle to the rotation axis of the disk (3).

According to the third aspect of the present invention, a gas supply port (12) for introducing a high-pressure gas into the blowing device (11) is equally allocated to the plurality of blowing devices (11). The configuration was adopted.

According to the present invention, the blowing device (11) has a ratio of the length (b) to the width (a) of one.
0: 1 or more vertically elongated slit-shaped gas outlet (11
a) and the gas outlet (11a) is arranged in the inner circumferential direction of the chamber (1).

Further, according to the present invention, the gas blowing pressure from the blowing device (11) is 1 kgf / cm.
² or more.

According to the present invention, the chamber (1) is provided with a one-way gas discharge valve (14) for keeping the internal pressure constant.

In the present invention, the kind of gas released from the gas outlet (11a) is air, an inert gas such as nitrogen, argon, helium, or a mixture thereof.

[0017]

FIG. 1 is a diagram showing a schematic configuration of a centrifugal disk spraying device according to the present invention.

In the drawing, reference numeral 1 denotes a closed chamber,
Air or an inert gas described later is introduced inside. A crucible 2 for melting a metal material which is a raw material of powder is attached to the top of the chamber 1, and a nozzle 9 for dropping the molten metal 4 in the crucible is provided at the bottom of the crucible 2. . A high-speed rotatable disk 3 is provided at the center of the chamber 1 directly below the nozzle 9.

FIG. 2 is an external perspective view of the disk 3. In the present embodiment, the disk 3 has, for example, an outer diameter of 40 m.
It is a circular disk having a V-shaped cross section of about m, and its inclination angle C is set to about 7 degrees with respect to the horizontal line. A rotating device (not shown) for rotating the disk 3 at a high speed is attached to the shaft 6 of the disk 3.

In the figure, reference numeral 8 denotes a metal powder collected at the bottom of the chamber 1, 10 denotes an outlet for taking out the metal powder 8, and a gas discharge valve 14 described later is provided near the outlet 10. is there.

Normally, the chamber 1 forms a balloon centered on the disk 3, and its horizontal cross section is circular as shown in FIG. 1 (b). In the present embodiment, the inner side wall of the chamber 1 (the position where the powder scatters most,
Or on an extension thereof), four blow-off devices 11 (hereinafter, referred to as blow-out nozzles 11) for emitting high-pressure gas and generating an airflow A in an inner circumferential direction (solid arrow direction) are attached, and These blow-out nozzles 11 are respectively arranged and fixed at an equal angle with respect to the rotation shaft 6 of the disk 3.

FIG. 3 is an external perspective view showing one embodiment of the blowing nozzle 11. As shown in FIG. The blow-out nozzle 11 has a gas inlet 11b at a lower portion into which a high-pressure gas from a gas supply port 12 described later is introduced, and the gas inlet 11b at a center in a vertical direction (that is, a direction of the rotation axis 6 of the disk 3). 11b is a box provided with a vertically elongated slit-shaped gas outlet 11a from which the high-pressure gas supplied from the gas outlet 11b is released. As described above, the plurality of boxes receive the high-pressure gas from the gas outlet 11a through the chamber 1 So that it blows out in the inner circumferential direction
1a is attached toward the inner peripheral direction of the chamber 1.

The gas outlet 11a is formed so that the ratio of the length (b) to the width (a) is 10: 1 or more. At this time, the gas blowing pressure is 1 kgf / cm ² or more. It is configured so that it can be secured. This blowing nozzle 11
(In other words, the atmosphere in the chamber 1) is air, an inert gas such as nitrogen, argon, or helium, or a mixed gas obtained by combining one or more of these.

A gas supply port 12 for introducing a high-pressure gas into each of the blowing nozzles 11 is provided on the outer wall of the chamber 1.
Are provided at several places, and the gas supply ports 12 are equally allocated to a plurality of blow-off nozzles 11 connected via a connection hose 13.

For example, in the present embodiment, two gas supply ports 12 are supplied to two blow nozzles 11 respectively. For example, if eight blow nozzles 11 are provided, Four blowing nozzles 11 connected to each other by the connecting hoses 13 from gas supply ports 12
Or two connected blowing nozzles 11
Are supplied from four gas supply ports 12 respectively. This is because if the number of blow nozzles 11 connected to one gas supply port 12 is different,
The pressure of the gas released from a becomes uneven and the chamber 1
This is because a uniform airflow is not formed in the inside.

In order to reduce the number of gas supply ports 12 to be introduced, a plurality of blow nozzles 11 are connected by connecting hoses 13 as in this embodiment.
Are connected to form a group, and gas can be supplied collectively thereto. Of course, a gas supply port 12 may be provided for each blow-off nozzle 11 to supply gas independently.

During the process, the gas pressure in the chamber 1 is gradually increased by the high-pressure gas discharged from the blowing nozzle 11. Therefore, in order to keep the internal pressure constant by allowing the gas inside to escape to the outside wall of the chamber 1, FIG.
An opening 20 as shown in FIG. In this embodiment, a one-way valve structure (movable valve) as shown in FIG. 4B is used instead of the opening 20 so that the inside atmosphere is not affected by an intrusion gas from the outside during the gas concentration control. A gas release valve 14 provided with

The gas release valve 14 opens and closes the valve section 16 based on the balance between the gas pressure in the chamber 1 and the pressure of a spring 15 acting to close the valve section 16. This is a mechanism for opening the valve portion 16 against the spring pressure and releasing the gas inside to the outside.

FIG. 5 shows how the molten metal 4 is scattered into the space by the centrifugal force of the disk 3 rotating at a high speed.

For example, zinc or a zinc alloy or the like is melted in the crucible 2, and the molten metal 4 in the crucible is placed in the center of the surface of the disk 3 located almost directly below the nozzle 9 provided at the bottom. Is continuously dropped at a predetermined flow rate determined by the hole diameter of the liquid.

At this time, since the disk 3 is rotated at a high speed by a rotating device (not shown) connected to the shaft 6, the molten material accumulated in a layer from the center of the V-shaped disk toward the outer periphery is rotated at a high speed. Due to the centrifugal force at the time, the liquid is sprayed into the space inside the chamber 1 sequentially from the disk end face.

The mist-like molten metal 4 scattered in the chamber 1 is cooled and solidified in an atmosphere of an inert gas or the like to form an irregularly shaped metal powder 8, which drops and accumulates at the bottom of the chamber 1.

According to the present invention, the blowing nozzle 11 is attached to the inner periphery of the chamber 1 to generate a gas flow A in the circumferential direction, so that the powder scatters radially from the center of the rotating disk 3. I changed the direction. Since the metal powder 8 scattered from the disk 3 is cooled and solidified while floating along the inner circumferential direction by the airflow A near the side wall, the metal powder 8 before solidification collides with the inner wall of the chamber 1. The amount of adhesion or deformation can be greatly reduced. This allows for a significant increase in yield. Therefore, by appropriately setting the conditions of the air flow A (that is, the type of gas used, the gas blowing pressure, etc.) in advance, the radial direction of the chamber 1 can be particularly shortened, and the CA device can be downsized.

Next, in order to specify the preferable conditions of the CA device,
Hereinafter, various confirmation tests shown in Examples 1 to 4 were performed. Here, the effect of atomizing conditions on the yield of metal powder was investigated.

In each of the confirmation tests, the following items a and b were used as common atomizing conditions. a. CA device Chamber: Approximately 2.5m in diameter.
Chamber atmosphere: air (oxygen concentration: 21%) Disk: diameter 40 mm, inclination angle 7 degrees Disk rotation speed: 15000 rpm Raw material: pure zinc 10000 g, melting temperature 6
00 ° C b. The direction of the air flow from the blow nozzle is the disk rotation direction. In addition, as an evaluation criterion of the present invention, it was determined to be effective when a yield of about 1.3 times or more as compared with a case without airflow (corresponding to a conventional apparatus). However, the yield is 100
The measured weight of the sieved powder less than 0μ. [Example 1]

In Example 1, the influence of the presence or absence of airflow on the powder yield was investigated.

However, the atomizing conditions of the first embodiment are as follows: the gas blowing pressure of the blowing nozzle 11 is 4 kgf / cm ² (slit size ratio b / a = 30 (a = 1 mm)), and the number of blowing nozzles 11 is set. Tested differently. Note that the blowing nozzles 11 are arranged at equal intervals around the disk 3.

The weight of the zinc powder obtained under the above conditions was measured,
The results are shown in Table 1.

[Table 1] According to Table 1, the generation of the air flow A in the chamber 1 increases the yield of zinc powder as compared with the conventional device (the case without the air flow in Table 1 corresponds to this). In particular,
The greater the number of the blowing nozzles 11, the greater the rate of increase. [Example 2]

In Example 2, the effect of the uniformity / non-uniformity of the blowing pressure on the powder yield was investigated.

However, the atomizing conditions of the second embodiment were such that the gas blowing pressure for one of the four blowing nozzles (slit size ratio b / a = 30) was different from the others. The other three nozzles were set at 4 kgf / cm ² .

The weight of the zinc powder obtained under the above conditions was measured,
The results are shown in Table 2.

[Table 2] According to Table 2, the yield when the blowing pressure is 4 kgf / cm ² is 7
Based on 500 g, one of them is on the low pressure side (2
kgf / cm ² ), the yield reduction rate is large, while the yield increase rate when the pressure is changed to the high pressure side (6 kgf / cm ² ) is small. In order to efficiently increase the yield, it is desirable that all the blowing pressures of the blowing nozzles 11 are set to be uniform to make the air flow A in the chamber 1 uniform. [Example 3]

In Example 3, the effect of the slit size ratio of the blowing nozzle 11 on the powder yield was investigated.

However, the atomizing conditions in the third embodiment are as follows: the number of the blowing nozzles is four (the blowing pressure is 4 kgf / cm ² ), and the slit dimensional ratio b / a (where a = 1 mm) of each blowing nozzle 11 is set. Changed.

The weight of the zinc powder obtained under the above conditions was measured,
The results are shown in Table 3.

[Table 3] In Table 3, the slit ratio of 10 to 50 is in a practical range, and the yield of zinc powder increases as the slit dimensional ratio increases. This is because the vertical width of the airflow A generated in the chamber 1 was increased by increasing the slit dimensional ratio.

Therefore, from this result, it can be seen that the blowing nozzle 11
Must be set to 10: 1 or more. [Example 4]

In Example 4, the effect of the blowing pressure of the blowing nozzle 11 on the powder yield was investigated. However, the atomizing condition of the fourth embodiment is such that the number of blowing nozzles is four (the blowing pressure is 4 kgf / cm ² , and the slit dimension ratio b / a = 3).
0), and the blowing pressure of each blowing nozzle 11 was changed.

The weight of the zinc powder obtained under the above conditions was measured,
The results are shown in Table 4. The blowing pressure in the table: 0 k
gf / cm ² is a state in which no airflow is generated.

[Table 4] In Table 4, the blowing pressure is 1 to 8 kgf / cm ² in a practical range, and the higher the blowing pressure, the higher the yield of zinc powder. Therefore, from this result, the blowing pressure is 1 kgf /
cm ² or more.

The following Examples 5 and 6 examine the effects of various atomizing conditions on the yield and external ratio of zinc powder. In each of the confirmation tests, the following items a,
b was the common atomizing condition. a. CA device Chamber: Approximately 2.5 m in diameter Disk: 40 mm in diameter, inclination angle 7 degrees Disk rotation speed: 15000 rpm Raw materials: Pure zinc 10000 g, melting temperature 6
00 ° C b. Number of blow-out nozzles attached: 4 Airflow direction: Disk rotation direction Blow-out pressure: 4 kgf / cm ² Slit size ratio: b / a = 30 (a = 1 mm) Also, the measured weight of sieved powder having a yield of less than 1000 μ as described above. The sieved powder having an external ratio of 700 to 50 μm was measured. [Example 5]

In Example 5, the influence of the atmosphere (oxygen concentration) in the chamber 1 on the powder yield and the external ratio was investigated.

However, the atmosphere (the type of gas released from the blowing nozzle) of the fifth embodiment is as follows. Argon gas (oxygen concentration: 0.07%) Argon gas + air (oxygen concentration: 1%) Argon gas + air (oxygen concentration: 5%) Nitrogen gas + air (oxygen concentration: 5%) Argon gas + air (oxygen Concentration: 10%) Air (oxygen concentration: 21%)

The weight of the zinc powder obtained under the above conditions was measured,
Table 5 shows the results.

[Table 5] In Table 5, although the external ratio changes depending on the oxygen concentration,
Under a certain condition of the oxygen concentration, there is no difference in external ratio between the presence and absence of airflow. Therefore, by appropriately adjusting the oxygen concentration of the gas, it is possible to increase only the yield without substantially changing the external ratio. Also,
The above effect is hardly affected by changing the type of gas. [Example 6]

In Example 6, the influence of the type of the discharge valve on the powder yield and the external ratio in a constant atmosphere was investigated. However, in the atomizing conditions of the sixth embodiment, the atmosphere was a mixture of argon and air (oxygen concentration: 5%), and the internal pressure adjusting mechanism was an open port (see FIG. 4A) and a movable valve (see FIG. 4B).

The weight of the zinc powder obtained under the above conditions was measured,
Table 5 shows the results.

[Table 6] According to Table 6, a high external ratio can be obtained by using a movable valve as the internal pressure adjusting mechanism. This is because the atmosphere (that is, the oxygen concentration) in the chamber 1 can always be kept constant by using the movable valve. On the other hand, when the opening is used, the external ratio is slightly reduced. This is because outside air was mixed in from the opening 20 during the gas concentration control, and the oxygen concentration in the chamber 1 was partially increased. Therefore, in order to always keep the external ratio of the obtained powder stable, it is effective to provide a one-way movable valve.

From the above confirmation tests of Examples 1 and 2, it was confirmed that the use of the centrifugal disk spraying apparatus of the present invention can increase the yield while maintaining the same external ratio as that of the prior art.

Then, it was confirmed in the following examples whether or not the zinc powder obtained by the present CA apparatus was applicable to the use of alkaline manganese batteries. [Example 7]

In Example 7, the influence of the presence or absence of airflow on the yield and external ratio of zinc powder for alkaline dry batteries was investigated.

However, the atomizing conditions are as follows: a. CA device Chamber: about 2.5 m in diameter Disk: 40 mm in diameter, 7 degree incline Disk rotation speed: 15000 rpm Raw material: zinc-based alloy (adding 2 or 3 trace elements) 10000 g Melting temperature: 600 ° C B. Number of blowout nozzles: 4 Airflow direction: Disk rotation direction Blowing pressure: 4 kgf / cm ² Slit dimension ratio: b / a = 30 (a = 1 mm) Atmosphere (gas blown from blow nozzle) Argon gas + air (oxygen concentration: 1%) Argon gas + air (oxygen concentration: 5%) Argon gas + air (oxygen concentration: 10%) Air (oxygen concentration: 21%) , To are movable valves, and are open ports. Also,
For both the yield and the external ratio, a sieved powder having a particle size of 50 to 700 μm was measured. The above particle size is the particle size of zinc powder conventionally used for alkaline manganese batteries.

The weight of the zinc powder produced under the above conditions was measured, and the results are shown in Table 7.

[Table 7]

According to Table 7, in the production of zinc powder for an alkaline manganese battery, by generating an air flow,
The yield can be increased with little change in external ratio. That is, by applying the present invention, a powder having exactly the same physical properties as the conventional apparatus can be obtained more efficiently. Example 8

In Example 8, the zinc powder obtained in Example 7 was used, and a KOH electrolyte and a thickener were added thereto to form a gel, and LR-6 type alkaline manganese was used as a negative electrode active material. A battery was manufactured. Next, the discharge performance was compared with that of a conventional product having the same positive electrode mixture, electrolyte solution, gelling agent and the like, and the results are shown in Table 8.

The discharge test was conducted under the environment of a temperature of 20 ° C.
Continuous discharge was performed with a discharge load resistance of 2Ω and a final voltage of 0.9V.

[Table 8] According to Table 8, the product of the present invention can achieve the same or higher discharge performance than the conventional product. As described above, according to the tests of Examples 7 and 8, by generating the airflow A in the chamber 1, zinc powder for an alkaline manganese battery can be efficiently produced, and the obtained zinc powder constitutes a negative electrode active material. Thus, it was confirmed that a higher performance alkaline manganese battery could be realized.

[0061]

As described above, according to the first aspect of the present invention, a blowing device for generating an air flow in the inner circumferential direction of a chamber by a high-pressure gas at a position where a large amount of metal powder is scattered inside the chamber. Are arranged along the inner circumferential direction of the chamber, so that the metal powder scattered by the centrifugal force from the rotating disk floats on the airflow and the cooling time of the powder is secured, so that the metal powder before solidification is removed. The amount of powder that collides and adheres to and deforms on the inner wall of the chamber is reduced, and the yield is greatly increased. Therefore, the production efficiency is improved, the cost can be reduced, and the radial direction of the chamber can be shortened structurally, so that the apparatus can be downsized.

According to the second aspect of the present invention,
Since the blowing device is disposed at an equal angle with respect to the rotation axis of the disk, the air flow generated in the inner circumferential direction of the chamber is made uniform, and the yield of powder increases.

According to the third aspect of the present invention,
Since the gas supply ports for introducing the high-pressure gas into the blowing device are equally allocated to the plurality of blowing devices, the gas pressure discharged from the gas outlet of the blowing nozzle becomes uniform,
A uniform airflow is formed in the chamber, and the yield of powder increases.

According to the fourth aspect of the present invention,
The gas outlet of the blowing device was formed into a vertically elongated slit having a ratio of length to width of 10: 1 or more. As described above, by limiting the slit dimensional ratio to a predetermined value or more and securing the vertical width of the generated air current, floating of the powder can be ensured, and the yield of the powder can be increased. .

According to the fifth aspect of the present invention,
Since the gas blowing pressure from the blowing device is set to 1 kgf / cm ² or more, the floating of the powder can be ensured, and the yield of the powder can be increased.

According to the present invention described in claim 6,
Since the chamber is provided with a one-way gas release valve for keeping the internal pressure constant, the atmosphere (that is, oxygen concentration) in the chamber can always be kept constant, so that the yield can be maintained without changing the external ratio of the powder. Can be increased.

Further, according to the present invention, the gas released from the gas outlet is air or nitrogen,
An inert gas such as argon or helium, or a mixture thereof was used. Thus, by appropriately selecting the type of the introduced gas, it is possible to more efficiently produce a metal powder having the same physical properties and shape as the conventional apparatus.

Therefore, by preparing zinc powder with the CA device of the present invention and using it as a negative electrode active material, an inexpensive and higher-performance alkaline manganese battery can be realized.

[Brief description of the drawings]

FIG. 1 is a view showing a schematic configuration of a centrifugal disk spraying device according to the present invention, wherein (a) is an external view and (b) is a horizontal sectional view thereof.

FIG. 2 is a view showing a disk, (a) is an external perspective view,
(B) is a side sectional view.

FIG. 3 is an external perspective view showing an embodiment of a blowing device.

4A and 4B show a mechanism for adjusting a chamber internal pressure, wherein FIG. 4A shows an opening and FIG. 4B shows a movable valve.

FIG. 5 is a diagram showing a state in which molten metal scatters from a rotating disk.

[Explanation of symbols]

 Reference Signs List 1 chamber 3 disk 4 molten metal 8 metal powder 11 blowing device (blowing nozzle) 11a gas outlet A air flow

Continuation of the front page (72) Inventor Mitsuhiro Nakamura 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd. (56) References JP-A-59-226104 (JP, A) JP-A-58- 52408 (JP, A) JP-A-4-310 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22F 9/10

Claims (7)

(57) [Claims] 1. A molten metal (4) inside a chamber (1).
Is dropped on a rotating disk (3), and the molten metal (4) is scattered by the centrifugal force to produce a metal powder (8). The metal powder inside the chamber (1) A plurality of blowing devices (11) for generating an air flow (A) in the inner peripheral direction of the chamber (1) by high-pressure gas at a position where the body (8) is scattered are arranged along the inner peripheral direction of the chamber (1). A centrifugal disk spraying device characterized by comprising: 2. A centrifugal disk spraying device according to claim 1, wherein said blowing device (11) is arranged at an equal angle with respect to a rotation axis of said disk (3). 3. A gas supply port (12) for introducing a high-pressure gas into said blowing device (11) is equally allocated to said plurality of blowing devices (11). The centrifugal disk spraying device according to claim 2. 4. The blow-off device (11) includes a vertically slit gas outlet (11a) having a ratio of length (b) to width (a) of 10: 1 or more, and the gas outlet. The centrifugal disk spraying device according to any one of claims 1 to 3, wherein (11a) is arranged toward an inner peripheral direction of the chamber (1). 5. The centrifugal disk spraying device according to claim 1, wherein a gas blowing pressure from the blowing device (11) is 1 kgf / cm ² or more. 6. The method according to claim 1, wherein the chamber is provided with a one-way gas release valve for keeping the internal pressure constant. Centrifugal disc spraying equipment. 7. The gas emission from the gas outlet (11a) is air, an inert gas such as nitrogen, argon or helium, or a mixture thereof. The centrifugal disk spraying device according to any one of the above.