JP2004292223A - Powder production apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder production apparatus which has uniform temperature distribution in a reaction part and thus realizes homogeneous powder production. <P>SOLUTION: The powder production apparatus 1 is provided with: a cylindrical-shaped reaction part 23 which has a circular section perpendicular to its axis and is supplied with fine mist including a powder raw material; and a plurality of burners 41 for spurting flame arranged along the inner circumference of the circle in the section perpendicular to the axis. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a powder manufacturing apparatus applied to, for example, manufacturing of secondary battery and semiconductor materials.
[0002]
[Prior art]
It is important to control the chemical composition and microstructure of secondary batteries and the like. In addition to the solid-phase reaction method and liquid-phase reaction method, powder There is a method using a thermal spray pyrolysis method.
[0003]
FIG. 3 shows a powder manufacturing apparatus 50 using the flame spray pyrolysis method. The burner 52 injects a flame upward from the bottom of a tubular reaction section 51, and a burner 52 is provided on a side of the burner 52. A spray device 53 is provided which is arranged in parallel and sprays a fine mist containing a powder material upward from the bottom of the reaction section 51.
[0004]
[Problems to be solved by the invention]
In the reaction section 51 of the powder production apparatus 50, it is desirable to obtain a uniform temperature distribution in the radial direction, and strict temperature control is required. However, as shown in FIG. 4, in the case of the powder manufacturing apparatus 50, the temperature rapidly rises near the burner 52, and decreases as the distance from the burner 52 increases, resulting in an uneven temperature distribution. . For this reason, there was a problem that a homogeneous powder could not be obtained.
[0005]
The present invention has been made to eliminate the conventional problems, and has as its object to provide a powder production apparatus which makes the temperature distribution in the reaction section uniform and enables uniform powder production. .
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the first invention has a cylindrical shape in which the inner periphery of a cross section perpendicular to the axis has no corner portion smaller than 90 °, and a fine mist containing a powder raw material is supplied. A configuration including a reaction section and a plurality of burners arranged so as to be capable of flame injection along the inner periphery of the cross section perpendicular to the axis is provided.
[0007]
According to a second aspect of the invention, in addition to the configuration of the first aspect, the temperature in the reaction section is adjustable.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
1 and 2 show a powder manufacturing apparatus 1 according to the present invention. The powder manufacturing apparatus 1 includes a powder generator 11, a powder collecting unit 12, and a suction device 13, each of which includes a duct 14 and a suction device 13. And 15.
[0009]
The powder generator 11 is a hollow body, and is roughly divided into a fine mist introduction unit 21, a fine mist storage unit 22, and a reaction unit 23. The fine mist introduction unit 21 is located on the lower side of the powder generator 11, The cylindrical reaction part 23 is provided toward the fine mist storage part 22, and extends above the fine mist storage part 22.
The powder collecting section 12 has a built-in filter member for separating fine particles and gas, for example, a bag filter 24.
The suction device 13 is provided to suck the inside of the powder generator 11 through the duct 14, the bag filter 24 in the powder collection unit 12 and the duct 15, and discharge the gas that has passed through the bag filter 24 to the outside. ing. Therefore, in the powder generator 11, a flow of fluid from the fine mist introduction unit 21 to the duct 14 via the fine mist storage unit 22 and the reaction unit 23 is formed by the action of the suction device 13.
[0010]
The powder generator 11 will be described in further detail. The fine mist introduction part 21 is fixed to the side of the fine mist storage part 22 and has a funnel-shaped introduction pipe 31 that expands toward the fine mist storage part 22; A fluid nozzle, for example, a two-fluid nozzle 32, which is attached to the small-diameter end of the introduction pipe 31 and sprays the solution containing the powdery raw material and the high-pressure air toward the fine mist storage unit 22 is formed.
[0011]
The fine mist storage section 22 has a volume for diffusing the fine mist containing the powder material sprayed from the two-fluid nozzle 32, and has a space for temporarily storing the fine mist therein.
[0012]
The reaction part 23 has a cylindrical shape having a circular cross section perpendicular to the axis, and four burners 41 are provided in the reaction part 23 so that a flame can be injected along the inner peripheral surface also having a circular cross section perpendicular to the axis. Arranged in tiers. And, by such a burner arrangement, the swirling flow of the flame is generated, the internal temperature becomes uniform, and the fine mist from the fine mist storage unit 22 also flows along the swirling flow, and the convection time becomes longer. 23 can be shortened. The reaction section 23 has a cooling gas supply unit 42 for supplying a cooling gas, for example, cooling air to a space below the burner 41. The temperature in the reaction section 23 can be adjusted by adjusting the flow rate of the fuel to the burner 41 and by adjusting the flow rate of the cooling gas from the cooling gas supply means 42. The cooling gas supply means 42 is not always required.
[0013]
Next, a powder generation process in the powder generator 11 having the above configuration will be described.
A solution such as a hydroxide, a nitrate, a sulfate, or a carbonate is pumped into the two-fluid nozzle 32 by a pump (not shown), and the solution is sprayed from the two-fluid nozzle 32 together with high-pressure air into the introduction pipe 31. As a result, a fine mist having an average diameter of about 10 μm is generated. The fine mist flows from the introduction pipe 31 into the fine mist storage 22, and the flow velocity is reduced to be laminar. The fine mist having a relatively large diameter is wet when it comes into contact with the wall surface and is wetted by the fine mist storage 22. On the other hand, even if the fine mist having a relatively small diameter contacts the wall surface, the surface mist of the fine mist itself is not greatly wetted. As a result, fine mist having a small diameter distribution standard deviation remains, and the remaining fine mist is sucked from the fine mist storage unit 22 toward the duct 14 and reaches the reaction unit 23.
[0014]
In the illustrated example, the burners 41 of the reaction unit 23 are arranged in two stages of four each, and the flame flow is injected in the circumferential direction in the reaction unit 23 to form a swirling flow. Thereby, the temperature in the reaction part 23 becomes uniform, and the fine mist flows along the flow line of the swirling flow. For this reason, it is possible to secure a sufficient residence time for the droplets to evaporate and thermally decompose. Then, thermal decomposition, melting, and synthesis occur instantaneously in the reaction section 23, and a target powder treatment is performed.
[0015]
For example, when lithium manganate is prepared using a nitrate solution, lithium manganate may not become a fine powder having a desired shape under an atmosphere having a sharp temperature gradient. For this reason, it is necessary to strictly control the rate of temperature rise in the reaction section 23. Therefore, the present invention does not limit the number of burners 41, but the number of burners 41 in the circumferential direction and the number of axial stages so as to realize an axial temperature distribution according to the processing solution and the like in the reaction section 23. May be determined and the burner 41 may be arranged.
Further, an optimum temperature distribution may be obtained by adjusting the fuel flow rate or the cooling gas flow rate of the burner 41 described above by a temperature control device (not shown).
[0016]
The powder obtained by the thermal decomposition in this manner becomes an ultrafine powder having a diameter of the order of nanometers. In the process from the powder generator 11 to the powder collection unit 12 via the duct 14 together with the exhaust gas, the powder is obtained. The powder is cooled below the heat-resistant temperature of the powder collecting unit 12. Then, the solid powder is guided to the powder collecting section 12 together with the exhaust gas, separated from the exhaust gas by the bag filter 24, the powder is collected in the powder collecting section 12, and the exhaust gas passing through the bag filter 24 is passed through the duct 15. Is discharged to the outside by the suction device 13 through the.
[0017]
The pressure in the powder generator 11 may be lower than the atmospheric pressure, may be the atmospheric pressure, or may be higher than the atmospheric pressure. Further, the kind of the atmosphere gas in the powder generator 11 is not limited at all, and various atmosphere gases are applied.
In addition, the present invention does not limit the cross-sectional shape of the reaction section 23 to a circular shape, and it is sufficient that the inner circumference of the cross section perpendicular to the axis has a cylindrical shape having no corner smaller than 90 °. For example, a cross-sectional shape such as a pentagon or a hexagon may be used.
Further, the present invention does not limit the number of the fine mist introduction portions 21, and the number of the fine mist introduction portions 21 may be one.
In addition, the present invention is not limited to the two-fluid nozzle 32, and the fine mist may be ejected to the fine mist introduction unit 21 using a plurality of nozzles.
[0018]
【The invention's effect】
As is clear from the above description, according to the first invention, the fine mist containing the powder raw material has a cylindrical shape in which the inner circumference of the cross section perpendicular to the axis has no corner portion smaller than 90 °. It is configured to include a supplied reaction section and a plurality of burners arranged so as to be capable of flame injection along the inner periphery of the cross section perpendicular to the axis.
Therefore, there is no dead space in the reaction zone where the flame does not reach, the swirling flow of the flame is formed along the circumferential direction, a uniform temperature distribution is obtained, and the fine mist flows along the swirling flow streamline. As a result, it is possible to secure a sufficient residence time for the droplets to evaporate and thermally decompose, to produce a homogeneous powder, to shorten the length of the reaction section, and to reduce the entire apparatus. There are effects such as compactness.
[0019]
According to the second aspect, in addition to the configuration of the first aspect, the temperature in the reaction section is adjustable.
For this reason, in addition to the above effects, it is possible to strictly control the rate of temperature rise in the reaction section according to the processing solution and the like, and it is possible to ensure good quality even if the type of powder is different. It works.
[Brief description of the drawings]
FIG. 1 is a view schematically showing an overall configuration of a powder production apparatus according to the present invention.
FIG. 2 is a cross-sectional view of a reaction section in the powder manufacturing apparatus shown in FIG.
FIG. 3 is a view schematically showing a conventional powder manufacturing apparatus.
4 is a diagram showing a temperature distribution in the conventional powder manufacturing apparatus shown in FIG.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 powder production apparatus 11 powder generator 12 powder collection unit 13 suction device 14, 15 duct 21 fine mist introduction unit 22 fine mist storage unit 23 reaction unit 24 bag filter 31 introduction pipe 32 two-fluid nozzle 41 burner 42 cooling gas Supply means

Claims (2)

The inner periphery of the section perpendicular to the axis has a cylindrical shape having no corners smaller than 90 °, and the reaction section to which the fine mist containing the powder raw material is supplied, and the inner periphery of the section perpendicular to the axis, And a plurality of burners arranged so as to be capable of injecting a flame. The powder production apparatus according to claim 1, wherein the temperature in the reaction section is adjustable.

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