JP6205442B2 - Metal powder production equipment - Google Patents

Description

  The present invention relates to a metal powder production apparatus for producing metal powder.

  Conventionally, the atomizing method has been widely used as a method for producing metal powder. As an atomizing method, there is a gas atomizing method in which a metal powder is produced by injecting a combustion flame onto a molten metal to pulverize the molten metal and solidify the obtained fine metal droplets (see, for example, Patent Document 1). ). In the metal powder manufacturing apparatus using the gas atomization method, the manufactured metal powder is collected inside the container.

JP-A-10-176206

  By the way, the combustion flame can be obtained, for example, by burning an air-fuel mixture obtained by mixing hydrocarbons such as gas and kerosene and air, but when hydrogen reacts with oxygen and burns, steam is generated. And the water vapor | steam in a container touched the hot metal droplet immediately after the molten metal was crushed, and the oxidized metal powder might be produced | generated.

  The present invention has been made paying attention to such problems, and an object of the present invention is to provide a metal powder production apparatus capable of obtaining a metal powder in which oxidation is suppressed.

  The metal powder manufacturing apparatus according to claim 1, wherein a supply means provided with a supply port for supplying molten metal or a metal material, and the molten metal disposed around the supply port and supplied from the supply port, Combustion flame injection means for injecting and atomizing a combustion flame from the combustion flame injection port to the outer peripheral surface of the metal material, and extending to at least a region where the molten metal is atomized from the combustion flame injection port, and the combustion flame is atomized And a cylindrical shield means surrounding the entire circumference of the molten metal, and a gas supply means for filling at least one of an inert gas and a reducing gas in the shield means.

  In the metal powder manufacturing apparatus according to claim 1, the molten metal is injected from the combustion flame injection port of the combustion flame injection means to the molten metal or metal material supplied from the supply means, so that the molten metal is It is crushed and atomized. Thereafter, the molten metal fine particles are cooled to form metal powder.

  Further, in this metal powder production apparatus, the cylindrical shield means surrounding the entire circumference of the combustion flame and the atomized molten metal extends at least from the combustion flame injection port to the atomized area of the molten metal, and Since the inside of the shielding means is filled with at least one of an inert gas and a reducing gas by the gas supply means, oxygen can be prevented from entering the shielding means, and high-temperature metal fine particles immediately after atomization can be prevented. At least one of the active gas and the reducing gas can be covered. Thereby, the contact between the metal fine particles and oxygen can be suppressed until the metal fine particles are cooled to some extent, and a metal powder with suppressed oxidation can be obtained.

  According to a second aspect of the present invention, in the metal powder manufacturing apparatus according to the first aspect, the shielding means includes a gas injection port for ejecting at least one of an inert gas and a reducing gas. A plurality are arranged along the circumferential direction.

  In the metal powder manufacturing apparatus according to claim 2, since at least one of the inert gas and the reducing gas is ejected from the plurality of gas injection ports toward the inside of the shielding means, the inert gas and Compared to the case where at least one of the reducing gas is ejected, the inside of the shield means can be filled with at least one of the inert gas and the reducing gas without unevenness.

  According to a third aspect of the present invention, in the metal powder manufacturing apparatus according to the first or second aspect of the present invention, the apparatus has a cooling means for cooling the atomized metal fine particles by spraying a cooling medium.

  In the metal powder manufacturing apparatus according to the third aspect, the cooling medium can be sprayed by the cooling means onto the atomized high-temperature metal fine particles. An amorphous metal powder can be obtained by spraying a cooling medium on the metal powder to rapidly cool the metal fine particles.

  According to a fourth aspect of the present invention, in the metal powder manufacturing apparatus according to the third aspect, the cooling means cools the metal particles flowing down through the shield means by spraying a cooling medium.

  In the metal powder manufacturing apparatus according to the fourth aspect, the cooling medium can be sprayed by the cooling means to the high-temperature metal fine particles flowing down inside the shield means. By spraying a cooling medium on the metal fine particles to rapidly cool the metal fine particles, amorphous metal fine particles can be obtained.

  Further, since the shielding means can cover the metal fine particles at least one of the inert gas and the reducing gas in the shielding means until cooled to a temperature at which oxidation is difficult, a metal powder with further reduced oxidation is obtained. be able to. The shield means can be lengthened so as to cover at least one of the inert gas and the reducing gas until the metal fine particles are cooled to a temperature at which the metal fine particles are not oxidized.

  According to a fifth aspect of the present invention, in the metal powder manufacturing apparatus according to any one of the first to fourth aspects, the combustion flame injection port is an annular annular injection port that surrounds the supply port.

  In the configuration in which the combustion flame is injected by a plurality of burners to surround the molten metal, the positioning of the burner is complicated. However, in the metal powder manufacturing apparatus according to claim 4, the combustion flame is injected from the annular injection port so that a gap is formed. It is possible to surround the molten metal or the metal material with the combustion flame and inject the combustion flame uniformly on the outer peripheral surface of the molten metal or the metal material.

  In this case, it is possible to easily prevent the molten metal from being scattered so as to escape from the combustion flame at a position where the combustion flame collides with the molten metal or the metal material. For this reason, uniform atomization is possible with respect to the molten metal, and a fine and uniform spherical metal powder can be obtained. In addition, the production efficiency of the metal powder can be increased.

  The metal powder production apparatus of the present invention has an excellent effect that a metal powder with suppressed oxidation can be obtained.

It is a side view which shows the whole structure of the metal powder manufacturing apparatus which concerns on 1st Embodiment. (A) is sectional drawing which shows the principal part of the metal-powder manufacturing apparatus which concerns on 1st Embodiment, (B) is a front view of a pouring nozzle and a combustion flame injection port. It is sectional drawing which shows the principal part of the metal powder manufacturing apparatus which concerns on 2nd Embodiment. It is a front view which shows the principal part of the metal powder manufacturing apparatus which concerns on 3rd Embodiment. It is sectional drawing which shows the principal part of the metal powder manufacturing apparatus which concerns on 4th Embodiment.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a metal powder manufacturing apparatus 10 according to the first embodiment of the present invention.
As shown in FIG. 1, the metal powder manufacturing apparatus 10 of this embodiment is a so-called confined type, a supply means 12 for supplying molten metal, and pulverizing the molten metal into metal droplets, that is, atomizing. Jet burner 14, recovery tower 18 for temporarily recovering metal powder, shield 32, gas supply device 36 for supplying inert gas into shield 32, cooling water supply device for supplying cooling water for cooling metal droplets 44, a cyclone 48 for sucking the metal powder falling into the recovery tower 18 and the like.

  The recovery tower 18 includes a cylindrical portion 18A extending in the vertical direction, a ceiling portion 18B that closes the upper portion of the cylindrical portion 18A, and a cone-shaped bottom portion 18C that closes the lower portion of the cylindrical portion 18A. ing.

  The supply means 12 is arranged at the upper part of the recovery tower 18. As shown in FIG. 2A, the supply means 12 includes a container 20 that stores the molten metal M. A high frequency coil 22 for heating and melting metal is disposed on the outer peripheral side of the container 20.

  The supply means 12 has a pouring nozzle 24 communicating with the inside of the container 20 at the center below the bottom surface of the container 20, and the molten metal M stored inside the container 20 is moved downward from the pouring nozzle 24. It is possible to leak out. The pouring nozzle 24 has a tapered shape in which the outer shape of the tip gradually narrows downward.

  The jet burner 14 is disposed below the container 20 of the supply means 12 so that the pouring nozzle 24 is disposed inside the combustion flame injection port 28. The jet burner 14 includes one combustion chamber 26 and an annular combustion flame injection port 28 for injecting the flame jet 30 as shown in FIG. As shown in FIG. 2A, the combustion flame injection port 28 is formed so as to follow the tapered shape of the tip of the pouring nozzle 24.

  In the jet burner 14 of the present embodiment, for example, air and kerosene which is a hydrocarbon are mixed and burned in the combustion chamber 26, and the combustion flame injection port 28 is directed downward and inward from the combustion flame injection port 28. The frame jet 30 is ejected without a gap along the circumference.

  The combustion flame injection port 28 can inject the flame jet 30 at a speed higher than the speed of sound. The jet burner 14 surrounds the down stream Ma of the molten metal M supplied from the pouring nozzle 24 below the supply means 12 with the frame jet 30 and concentrates on a single point P of the down stream Ma. The jet 30 is jetted obliquely downward. Further, the jet burner 14 can collide the frame jet 30 with a uniform jet pressure without any gap along the outer periphery of the drooping downstream Ma of the molten metal M supplied from the pouring nozzle 24. Thus, when the flame jet 30 hits the down stream Ma of the molten metal M, the down stream Ma is crushed and atomized, that is, a mist-like fine metal droplet (non-solidified metal) Fine particles) are generated.

  Note that the jet burner 14 of the present embodiment is configured to inject the frame jet 30 at an angle of about 30 degrees with respect to the vertical direction from an obliquely upward direction with respect to the drooping downstream Ma.

  A shield 32 made of metal or the like is disposed on the lower surface of the ceiling portion 18B of the recovery tower 18. The shield 32 includes a cylindrical main body 32A extending along the vertical direction, and a flange 32B formed at the upper end of the main body 32A. The flange 32B is fixed to the ceiling 18B with a bolt or the like (not shown). Yes.

  The main body portion 32A of the shield 32 extends downward from one place P where the frame jets 30 are concentrated from the lower surface of the ceiling portion 18B. That is, the main body portion 32A of the shield 32 is a portion that is at a high temperature before being cooled with the cooling water W described later (ie, a state that is easily oxidized) among the mist-like portions generated by crushing the molten metal M. Part A) is enclosed.

  One end of a pipe 34 for injecting the inert gas G into the inside of the main body 32A is opened in the main body 32A of the shield 32 at an intermediate portion in the vertical direction. The other end of the pipe 34 is connected to a gas supply device 36. One end of the pipe 34 corresponds to the gas injection port of the present invention.

  The gas supply apparatus 36 of this embodiment supplies nitrogen gas as the inert gas G, and includes a cylinder 38 filled with the inert gas G, a regulator 40 that adjusts the outflow amount of the inert gas G, and the like. It consists of The gas supply device 36 of the present embodiment supplies nitrogen gas as the inert gas G, but by changing the type of gas filled in the cylinder 38, other than nitrogen gas such as hydrogen gas and argon gas. Inert gas can also be supplied, and reducing gas, such as carbon monoxide and hydrogen, can also be supplied. The gas supply device 36 can also fill the cylinder 38 with a gas obtained by mixing an inert gas and a reducing gas, and supply a gas obtained by mixing the inert gas and the reducing gas.

A plurality of cooling nozzles 16 are provided in the circumferential direction on the outer peripheral side of the shield 32 on the lower surface of the ceiling portion 18B of the recovery tower 18. As shown in FIG. 1, one end of a pipe 42 is connected to the cooling nozzle 16, and the other end of the pipe 42 is connected to a cooling water supply device 44.
As shown in FIG. 2, the cooling nozzle 16 can spray the cooling water W toward the high-temperature metal fine particles flowing down vertically from the lower end of the shield 32 to rapidly cool the metal fine particles.

  Note that one end of a duct 46 is open at the bottom 18 </ b> C of the recovery tower 18, and the other end of the duct 46 is connected to a cyclone 48. The cyclone 48 sucks the metal powder MP in the recovery tower 18 and the gas to separate the gas and the metal powder MP, and releases the separated gas to the atmosphere. The metal powder MP is disposed below the cyclone 48. It discharges to the receptacle 50.

(Function, effect)
Next, the operation and effect of the metal powder manufacturing apparatus 10 of this embodiment will be described.
In the metal powder manufacturing apparatus 10, the molten metal M heated and melted by the high-frequency coil 22 is stored inside the container 20, and the molten metal M flows down vertically from the pouring nozzle 24 as a drooping downstream Ma.

  Then, the flame jet 30 is injected at a speed higher than the speed of sound from the combustion flame injection port 28 of the jet burner 14 with respect to the downstream downstream Ma, and the downstream downstream Ma is crushed and atomized, that is, mist-like. Fine metal droplets (non-solidified metal fine particles) are generated. In addition, the inside of the shield 32 is previously filled with the inert gas G before crushing the drooping downstream Ma.

  The mist-like fine metal droplets (non-solidified metal fine particles) pass through the inside of the shield 32, and then are rapidly cooled with the mist-like cooling water W to become the metal powder MP. To fall.

  In this embodiment, the amorphous metal powder MP can be obtained by rapidly cooling the high-temperature metal droplets with the cooling water W. Then, the metal powder MP that has fallen to the bottom 18 </ b> C of the recovery tower 18 is sucked by the cyclone 48 and recovered in the receiver 50.

  By the way, in the metal powder manufacturing apparatus 10 of this embodiment, since kerosene and air are mixed and the flame jet 30 is produced | generated, the hydrogen in kerosene and the oxygen in the air react, and water vapor | steam is produced | generated. Water vapor is also generated by spraying the cooling water W onto the high temperature metal droplets. Oxygen in the air inside the recovery tower 18 and oxygen in the water vapor are causative substances that oxidize the metal.

  In the metal powder production apparatus 10 of the present embodiment, when producing the metal powder MP, an inert gas is introduced from the pipe 34 to the inside of the shield 32 in order to prevent oxygen from touching the hot metal droplets as much as possible. Nitrogen gas, which is G, is jetted to fill the inside of the shield 32 with nitrogen gas so that water vapor (oxygen) does not enter the inside of the shield 32. That is, when manufacturing the metal powder MP, the inside of the shield 32 is brought into an oxygen-free state.

  The shield 32 extends from the pouring nozzle 24 to a position immediately before the atomized fine metal droplets (high-temperature metal fine particles not solidified) are cooled by the cooling water W. Since the inside of the shield 32 is covered with nitrogen gas filled, oxygen and oxygen are compared with the case where there is no shield 32 filled with nitrogen gas until the metal droplet is cooled by the cooling water W. Can be suppressed. Thereby, metal powder MP in which oxidation is suppressed can be obtained.

  In the metal powder manufacturing apparatus 10 of the present embodiment, the flame jet 30 is hotter than the high-pressure water of the water atomization method or the high-pressure gas of the gas atomization method, so that the flow velocity of the sprayed fluid is increased as compared with the water atomization method or the gas atomization method. Is possible.

  Moreover, since the flame jet 30 is high temperature, the molten metal M can be atomized without cooling, and it is not necessary to raise the temperature of the molten metal M more than necessary. For example, compared to conventional water atomization and gas atomization methods, the temperature of the molten metal can be set lower by about 50 to 100 ° C., so that the molten metal M is finely pulverized under conditions that make it more amorphous. Can do.

  Moreover, it is preferable that the pressure inside the shield 32 is set higher than the pressure inside the recovery tower 18 (pressure outside the shield 32) so that water vapor does not enter the inside of the shield 32. The pressure in the shield 32 can be adjusted by adjusting the amount of the inert gas G supplied into the shield 32 by the regulator 40.

  The shield 32 preferably has a length and an inner diameter so that fine metal droplets do not adhere to and accumulate on the inner surface.

  Here, it is preferable that the distance L (see FIG. 2) from when the high-temperature metal droplet is discharged from the lower end of the shield 32 to hit the cooling water W is as short as possible. This is because if the distance L from the lower end of the shield 32 until the cooling water W hits the hot metal droplet is long, the time during which the hot metal droplet discharged from the lower end of the shield 32 hits the atmosphere containing oxygen is long. This is because the metal becomes easier to oxidize as it becomes longer.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 3, in the metal powder manufacturing apparatus 10 of the present embodiment, the length of the shield 32 is formed longer than that of the first embodiment, and the cooling nozzle 16 is provided on the shield 32. The cooling nozzle 16 is disposed so as to spray the cooling water W onto the metal droplets (non-solidified metal fine particles) inside the shield 32. Further, the lower end of the shield 32 is positioned below the position where the falling metal droplet and the cooling water W meet.

  Also in this embodiment, the inside of the shield 32 is filled with the inert gas G when the metal powder MP is manufactured.

  In the present embodiment, the shield 32 is lengthened, and the flowing metal powder MP is covered with an inert gas G until the metal powder MP is lowered to a temperature at which it is difficult to oxidize, and the metal powder MP is sufficiently cooled and then discharged to the outside of the shield 32. Therefore, the metal powder MP in which oxidation is further suppressed can be obtained, and in some cases, the metal powder MP that is not oxidized can be obtained.

  Since the conditions for oxidation (temperature, etc.) vary depending on the type of metal or the like, it is preferable to obtain the length of the shield 32 by conducting an experiment or the like for each type of metal in advance so that the oxidation can be suppressed.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.

  In the first embodiment, the jet burner 14 includes the annular combustion flame injection port 28. However, the present invention is not limited to this, and instead of the annular combustion flame injection port 28, as shown in FIG. In addition, a plurality of combustion flame injection ports 51 may be arranged along the circumferential direction of the pouring nozzle 24.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted.

  In the metal powder manufacturing apparatus 10 of the first embodiment, the jet burner 14 includes the annular combustion flame injection port 28. However, the present invention is not limited to this, and as shown in FIG. You may arrange | position the some jet burner 54 which injects the substantially linear flame | frame jet 52 toward the drooping downstream Ma on the outer periphery.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and other various modifications can be made without departing from the spirit of the present invention. It is.

  In the metal powder manufacturing apparatus 10 of the above embodiment, the amorphous metal powder MP is obtained by rapidly cooling the metal droplets with cooling water. The spray amount of the water W may be reduced or the spray of the cooling water W may be stopped. In this case, since it takes time to lower the temperature of the metal powder MP, it is preferable to lengthen the shield 32.

  In the metal powder manufacturing apparatus 10 of the above embodiment, cooling water is used as the cooling medium, but a cooling medium other than water, such as liquid nitrogen or liquefied carbon dioxide gas, may be used instead of the cooling water.

  The metal powder manufacturing apparatus 10 is provided so that the supply means 12 can continuously supply a metal wire material that is a metal material (solid) downward, and the jet burner 14 injects a frame jet 30 onto the metal wire material. It may be provided. In this case, the molten metal can be pulverized while melting the metal wire by injecting the high-temperature frame jet 30 onto the metal wire.

  The shield 32 may have a shape in which the diameter is gradually increased downward.

  In the above embodiment, nitrogen gas is supplied into the shield 32 as the inert gas G. However, an inert gas other than nitrogen gas such as hydrogen gas or argon gas may be supplied, such as carbon monoxide, hydrogen, etc. A reducing gas may be supplied, or a gas obtained by mixing an inert gas and a reducing gas may be supplied.

  In addition, in the metal powder manufacturing apparatus 10 of the said embodiment, the molten metal M is dropped below, the flame jet 30 injected toward diagonally downward with respect to the dropped molten metal M is applied, and atomization (atomization) However, the present invention is not limited to this, and the metal powder manufacturing apparatus 10 is ejected in the lateral direction or the upward direction depending on the metal material. The molten metal M is sucked up by the suction force generated by the flame jet 30, and the molten metal fine particles atomized by applying the flame jet 30 to the sucked molten metal M are laterally, obliquely upward, or upward. It may be configured to flow in the direction. In these cases, the direction of the shield 32 is set along the flowing direction of the metal fine particles.

10 Metal Powder Manufacturing Equipment 12 Supply Unit (Supply Unit)
16 Cooling nozzle (cooling means)
14 Jet burner (combustion flame injection means)
24 Pouring nozzle (supply port)
28 Combustion flame injection port 30 Flame jet (combustion flame)
32 Shield (Shielding means)
34 Piping (gas injection port)
36 Gas supply device (gas supply means)
M Molten metal

Claims (5)

Supply means provided with a supply port for supplying molten metal or metal material;
Combustion flame injection means that is arranged around the supply port and atomizes by injecting a combustion flame from the combustion flame injection port to the outer peripheral surface of the molten metal or metal material supplied from the supply port;
A cylindrical shield means extending from at least the combustion flame injection port to a region where the molten metal is atomized and surrounding the entire circumference of the combustion flame and the atomized molten metal;
A gas supply means for filling the shielding means with at least one of an inert gas and a reducing gas;
A metal powder manufacturing apparatus.   2. The metal powder production apparatus according to claim 1, wherein a plurality of gas injection ports for injecting at least one of an inert gas and a reducing gas are arranged in the shield means along a circumferential direction of the shield means. .   The metal powder manufacturing apparatus according to claim 1, further comprising a cooling unit that cools the atomized metal fine particles by spraying a cooling medium.   The metal powder manufacturing apparatus according to claim 3, wherein the cooling means cools the metal particles flowing through the shield means by spraying a cooling medium.   The metal powder manufacturing apparatus according to any one of claims 1 to 4, wherein the combustion flame injection port is an annular ring injection port that surrounds the supply port.

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