WO2016163643A1

WO2016163643A1 - Fine-powder production device and method

Info

Publication number: WO2016163643A1
Application number: PCT/KR2016/001931
Authority: WO
Inventors: 양상선; 김용진; 양동열; 임태수; 김기봉
Original assignee: 한국기계연구원
Priority date: 2015-04-07
Filing date: 2016-02-26
Publication date: 2016-10-13

Abstract

The present invention relates to a fine-powder production device and method wherein, in the first instance, a molten raw material is disintegrated by using gas jetting, and, in the second instance, a fine powder of which the characteristics are controlled is produced by using liquid jetting. The fine-powder production device according to the present invention comprises: a molten metal supply unit which supplies a molten metal by melting a raw material; a gas jetting unit which is positioned underneath the molten metal supply unit and disintegrates the molten metal so as to form droplets by jetting a gas comprising an inert gas; a liquid jetting unit which is positioned underneath the gas jetting unit, and forms a fine powder by jetting a liquid, with adjustment of the position of jetting onto the drops formed by means of the gas jetting unit; and a fine powder capture unit into which falls a fine powder formed by means of the liquid jetting unit.

Description

Fine powder manufacturing apparatus and method

The present invention relates to a fine powder production apparatus and method. More specifically, the present invention relates to a fine powder production apparatus and method for pulverizing a molten raw material using first gas injection, and producing fine powder whose properties are controlled using second liquid injection.

The fine powder is made of fine powder of metal, and is used in various fields such as paints, painting tools, gold / silver printing inks, chemical industrial catalysts, raw materials for sparks, and metal reducing agents.

There are various types of the production method of such fine powder, the fine powder should have a finer size, and the productivity or production yield should be high. In general, as a method for preparing a fine powder, a wet method through a chemical method such as pulverization and precipitation of a solid metal, and a spraying method such as spraying using a spray nozzle after melting the metal material. In the above method, the spraying method may be classified into a water spraying method using a liquid such as water and a gas spraying method using a gas, depending on the cooling medium used.

In the conventional method for producing fine powder by gas atomization (Gas Atomization) in general, while flowing the molten metal through the injection nozzle to produce a metal powder by injecting an inert gas such as argon or nitrogen at room temperature, the particle size of the metal powder produced Was formed on the average of about 100 μm. Metals have low melting points such as zinc (Zn), aluminum (Al), tin (Sn), and stainless steel, copper (Cu), iron (Fe), nickel (Ni), and cobalt (Co) depending on the melting temperature. It can be divided into a metal having a high melting point or a multi-element alloy and the like.

On the other hand, in order to produce amorphous metal and alloy powder, the cooling rate should be very fast when producing a solid powder in the liquid phase. For this reason, it is difficult to produce amorphous powder in the gas injection method, and to solve this problem, spherical amorphous powder is prepared using expensive helium gas, which is a gas having a very high cooling rate, and a rotating copper disk mainly cooled after gas injection is manufactured. It has been studied how to produce spherical amorphous powders by cooling the powders and immersing the powders produced by the gas injection into lower stored water or liquid nitrogen. However, this method has to use expensive helium gas, there is a problem that the cost increases.

On the other hand, if the amorphous powder is produced by the water spray method, it is possible to manufacture the powder to an average size of 10 μm or less. However, irregularly shaped powders other than spherical powders are produced, thereby increasing the specific target of the powder and increasing the surface roughness.

In addition, in the case of spraying water, the fine powder may be oxidized depending on the alloy system due to the oxygen contained in the water, and additionally, a reduction process may be required. When oxidation occurs, it must be subjected to a reduction step, agglomeration between the powders during the reduction step necessarily requires a grinding step, there is a problem that the process is complicated, the cost increases. In addition, the gas injection and water injection method has a problem that it is difficult to control the fraction of the amorphous powder in the powder produced.

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) Korean Registered Patent No. 10-0800505

(Patent Document 2) Korean Patent Publication No. 10-2007-0105256

An object of the present invention is to provide a fine powder manufacturing apparatus and method for providing a fine powder consisting of at least one of a metal, an alloy of a metal and a metal / ceramic composite material.

Another technical problem to be achieved by the present invention is a fine powder production apparatus for producing fine powder by cooling the pulverized molten liquid droplets using a liquid spray that firstly pulverize the molten metal using a gas injection and secondly spraying a liquid such as water and To provide a method.

In order to achieve the above object, the fine powder production apparatus according to the present invention,

A molten metal supplier for melting a raw material to supply a molten metal; A gas injector positioned below the molten metal supply unit and configured to inject a gas including an inert gas to pulverize the molten metal to form droplets; Located under the gas injector, the liquid is injected to the droplets formed by the gas injector to inject a liquid such as water (for example, water or liquid nitrogen or liquid argon) to form a fine powder Injection unit; And a fine powder collecting unit in which the fine powder formed by the liquid spraying unit is dropped.

In addition, the fine powder production method according to the present invention,

Melting the raw material to form a molten metal, and then discharging the molten metal; Spraying an inert gas on the discharged molten metal to form droplets; Adjusting the position of the liquid to be sprayed on the droplets; And cooling the droplets to produce fine powder by spraying a liquid on the droplets.

According to the fine powder manufacturing apparatus and method according to the embodiment of the present invention, it is possible to produce a fine powder made of at least one of a metal, an alloy of a metal and a metal / ceramic composite material.

In addition, by spraying a gas of high temperature and high pressure to the molten metal to pulverize the molten stem to produce droplets of various shapes such as strip, elliptical, spherical shape, and by adjusting the position of the liquid injection nozzle to the desired position, liquid such as water (e.g. For example, water or liquid nitrogen or liquid argon) may be sprayed to prepare a fine powder of a desired shape.

In addition, by adjusting the position and the amount of the liquid to be sprayed can be produced in the metal powder and alloy powder, the shape, particle size, amorphous powder fraction, the powder inside the nano-grain size, surface roughness and the like are controlled.

1 is a view showing a fine powder manufacturing apparatus according to an embodiment of the present invention.

2 is an enlarged view of a portion of a fine powder production apparatus according to an embodiment of the present invention.

3 is an enlarged view of a part of a fine powder manufacturing apparatus according to an embodiment of the present invention, the shape of the droplets formed by melting the molten metal by the gas injection unit and the fine powder formed by the liquid injection unit Figure is a diagram.

Figure 4 is a view illustrating the shape of the liquid spray nozzle of the fine powder production apparatus according to an embodiment of the present invention.

Figure 5 is a flow chart showing a method for producing fine powder according to an embodiment of the present invention.

The fine powder production apparatus according to the present invention is not only capable of producing fine powders whose properties are controlled by using liquid injection, but also to contribute to cost reduction by widening the selection range of the inert gas in the inert gas injection process.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it is noted that the same reference numerals are assigned to the same components as much as possible, even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function is apparent to those skilled in the art or may obscure the gist of the present invention, the detailed description will be omitted.

As shown in Figure 1, the fine powder manufacturing apparatus 100 according to an embodiment of the present invention is a molten metal supply unit 110, gas injection unit 120, liquid injection unit 130, fine powder collecting unit 140 ).

The molten metal supply unit 110 supplies the molten metal by melting the raw material. For this purpose, the molten metal supply unit 110 may include a stirring motor 111, an impeller 112, an operation unit 113, an accommodation unit 114, a heater 115, and a crucible 116.

The molten metal supply unit 110 is provided with a crucible 116 and a heater 115 for melting the raw material, and an injection means for accommodating the raw material above the crucible 116 is provided. The raw material may be in the form of an ingot. The raw material may also include at least one of metals, alloys of metals and metal / ceramic composites. In addition, the raw material may be formed of a heterogeneous material. That is, the raw material may be a material formed by mixing two or more materials.

The molten metal supply part 110 includes an operation part 113 and a receiving part 114 as input means. Receiving unit 114 may be received a raw material therein. Receiving portion 114 may be formed to be rotated about the rotation axis is formed in the rotary shaft in a portion oriented in one direction from the center of the crucible. One side of the body of the receiving unit 114 is connected to the operation unit 113 to tilt the receiving unit 114 in one direction by a user operation so that the raw material contained in the receiving unit 114 can be introduced into the crucible 116. Can be. One end of the operation unit 113 is connected to the receiving unit 114, and the other end is formed to be exposed to the outside of the molten raw material supply unit 110, when the user grips the other end exposed, the receiving unit 114 is centered on the rotation axis As it rises in the holding direction, raw materials contained therein may be introduced into the crucible 116. In this case, the user may be provided with a motor and an operation switch, and the user may operate the operation switch, so that the accommodating part 114 may be inclined in one direction by the operation of the motor.

The molten metal supply unit 110 includes a heater 115 for heating the crucible 116 to melt a raw material. The crucible 116 is opened upwardly so that the raw material can be received upward. In addition, the crucible 116 may be formed so that the receiving area becomes narrower from the top to the bottom.

The molten metal supply unit 110 includes a stirring means so that the raw material is input and stirred. The stirring means includes a stirring motor 111 and an impeller 112. The stirring motor 111 is provided at one side of the molten metal supply part 100 to generate rotational force. The impeller 112 rotates so that the raw material is stirred using the rotational force.

The gas injection unit 120 injects gas into the molten metal discharged from the molten metal supply unit 110 to pulverize the molten metal, and the liquid injection unit 130 cools the liquid droplets formed by pulverizing the molten metal at a desired position to fine powder. Can be formed. The gas injection unit 120 and the liquid injection unit 130 will be described later with reference to FIGS. 2 and 3.

The fine powder collecting unit 140 is located at the bottom of the fine powder manufacturing apparatus 100, that is, the lower portion of the liquid spraying unit 130, and may collect the fine powder cooled by the liquid spraying unit 130. The fine powder collecting unit 140 may be implemented in the form of a chamber structurally connected to the molten metal supply unit 110.

As shown in FIG. 2, the gas injection unit 120 may include a gas storage unit 121, a gas heating unit 122, and a gas injection nozzle 123.

The gas storage unit 121 stores an inert gas such as nitrogen or argon. Conventionally, in order to prepare amorphous fine powder, expensive helium gas, which is a gas having a high cooling rate, should be used. However, according to the present invention, the cooling rate is slower than helium gas, but relatively low cost, without using such expensive helium gas. An amorphous fine powder can be prepared using an inert gas such as phosphorus nitrogen or argon. That is, the slow cooling rate can be compensated for by the liquid spraying treatment in the liquid spraying unit 130.

In order to produce a fine raw material powder, the velocity of the injection gas must be increased. To this end, the gas heating unit 122 receives an inert gas such as nitrogen or argon from the gas storage unit 121 and heats it. The heated gas pulverizes the molten metal by injecting the gas into the molten metal discharged from the molten metal supply unit 110 through the gas injection nozzle 123. The gas injection nozzle 123 may be a hole type or an open slit type.

At this time, the temperature of the gas injected from the gas injection unit 120 is preferably formed at room temperature, that is, 25 ° C to 750 ° C. If the temperature of the injected gas is less than 25 ° C., there is a problem in that the cooling cost to make the temperature is consumed and the economic effect is lowered. Therefore, the temperature of the gas injected from the gas injector 120 is preferably 25 ° C. or more. On the other hand, when the temperature of the injected gas exceeds 750 ° C., the manufacturing of the equipment is difficult to increase the cost there is a problem. Therefore, the temperature of the gas injected from the gas injector 120 is preferably 750 ° C. or less.

In addition, at this time, the pressure injected from the gas injection unit 120 is preferably formed to 1bar to 150bar. When the injection pressure is less than 1 bar, the grinding force due to the pressure is lowered because the size of the pulverized raw material powder is large, there is a problem that it is difficult to obtain a fine powder. Therefore, the pressure injected from the gas injection unit 120 is preferably 1 bar or more. On the other hand, if the injection pressure exceeds 150bar, there is a problem that the cost is increased because the production of the equipment is difficult. Therefore, the pressure injected from the gas injection unit 120 is preferably 150 bar or less.

The liquid spraying unit 130 forms a fine powder having a desired shape by spraying a liquid on the liquid droplets formed by pulverizing the molten metal by the gas spraying unit 120. Herein, the liquid may be water or liquid nitrogen or liquid argon. That is, by injecting water or liquid nitrogen or liquid argon into the droplets formed by pulverizing the molten metal by using an inert gas such as nitrogen or argon having a slow cooling rate, the slow cooling rate is compensated for, and the drop distance from the molten metal supply unit 110 is reduced. By spraying a liquid at a position where a desired shape is formed among various shapes according to the present invention, an amorphous fine powder having a desired shape can be manufactured. When spraying water, the fine powder may be oxidized due to the oxygen contained in the water, and additionally, a reduction process may be required. When spraying liquid nitrogen or liquid argon, the fine powder is not oxidized and thus no further reduction process is required.

On the other hand, the liquid injection unit 130 in the present invention is not intended for the purpose of micronization as in the prior art, but for the purpose of cooling the high-temperature droplets formed by gas injection, the quantity used is significantly higher than that of the conventional liquid injection. little. In addition, by controlling the position and the amount of water or liquid nitrogen or liquid argon to be sprayed, it is possible to simultaneously control the shape, nanocrystalline and amorphous fraction of the fine powder.

More specifically, the droplet formed by the gas injection unit 120 becomes more spherical due to the cohesive force of the droplet, the farther the falling distance from the gas injection unit 120. That is, the portion where the drop, which is the closest hem to the molten metal supply unit 110 starts, has a low cohesive force, and thus an irregularity is increased to form an irregular liquid, a strip liquid, or a ribbon liquid, and as the drop distance increases, The cohesive force of the enemy is gradually increased to form an elliptical liquid or a spherical liquid.

In order to manufacture a fine powder having a desired shape using the shape change of the droplet according to the falling distance, as shown in Figure 3, the liquid spraying unit 130, the liquid storage unit 131, the liquid spraying position It may include a control unit 132, a liquid pressurizing unit 133, and a liquid injection nozzle 134.

The liquid injection unit 130 is preferably installed spaced apart from the gas injection nozzle 123 of the gas injection unit 120 by 1 mm or more and 2000 mm or less. When the separation distance is less than 1 mm, it is difficult to manufacture nozzles having such a gap, and the distance between the gas injection nozzle 123 and the liquid injection unit 130 is so close that the gas and the liquid injection unit injected from the gas injection nozzle 123 are too close. Liquids sprayed from the liquid jet nozzle 134 of 130 affect each other, making it difficult to form fine powder of a desired quality. In addition, when the separation distance exceeds 2000 mm, the droplets formed by the gas injection unit 120 may be cooled before being cooled by the liquid injection unit 130, that is, during the drop, so that the formation of fine powder of a desired quality is achieved. There is a difficult problem.

The liquid storage unit 131 stores liquid to be injected through the liquid injection nozzle 134.

The liquid spray position adjusting unit 132 adjusts the vertical position of the liquid jet nozzle 134. For example, the liquid spraying position adjusting unit 132 supports the liquid spraying nozzle 134 and moves a support rail and a liquid spraying nozzle 134 installed on the support rail up and down to guide the movement in the vertical direction. It can be designed to include. Alternatively, the support may be provided in which the through holes are formed at predetermined vertical intervals, and the liquid injection nozzle 134 may be inserted into the through holes. In the former case, the position of the liquid ejection nozzle can be remotely controlled by controlling the movement of the motor from the outside, and in the latter case, the user can manually prepare the fine powder of the desired shape by placing the liquid ejection nozzle at the desired position. have. Of course, such a liquid injection position adjusting unit 132 is only an example, but is not limited thereto.

The liquid pressurizing unit 133 controls the pressure of the liquid to be injected through the liquid injection nozzle 134. If the injection pressure is less than 1bar, the amount of liquid that is a cooling medium is insufficient to cool the entire liquid droplets and powder produced in the gas injection unit, if the injection pressure exceeds 1500bar, there is a problem that the production of equipment difficult. Therefore, the pressure of the liquid injected through the liquid pressurizing unit 133 is preferably formed to 1bar to 1500bar.

The liquid jet nozzle 134 may be provided with at least one. More preferably, two or more are provided. When provided as one, only droplets close to the water injection nozzle 134 are cooled among the falling droplets, and the distant droplets may not be cooled, and thus two or more are spaced at equal distances around the falling droplets. It is desirable to have the droplets cool evenly.

4 illustrates a nozzle shape of the liquid jet nozzle 134. As shown in FIG. 4, the nozzle shape of the liquid jet nozzle 134 includes an open slit nozzle, a hole nozzle, and a multiple nozzle.

The open slit nozzle may spray liquid through the annular nozzle 134a. In the hole nozzle, a plurality of circular nozzles 134b are arranged at regular intervals to form an annular shape, and the liquid may be injected through the plurality of circular nozzles 134b. In the multi-nozzle, a plurality of polygonal (for example, triangular) nozzles 134c are arranged at regular intervals to form an annular shape, and the liquid may be injected through the plurality of polygonal nozzles 134c.

With reference to Figure 5 will be described a fine powder production method according to the present invention. Figure 5 is a flow chart showing a method for producing fine powder according to an embodiment of the present invention.

First, the molten metal supply unit 110 discharges the molten metal generated by melting the raw material through the molten metal outlet. (S110)

Then, inert gas such as nitrogen and argon is injected into the molten metal discharged through the molten metal outlet. At this time, the temperature of the inert gas is injected at room temperature, that is, 25 ° C to 750 ° C, the pressure is adjusted to 1 bar to 150 bar.

Then, the position of the liquid jet nozzle 134 is adjusted using the liquid jet position adjusting unit 132. (S130) At this time, the position of the liquid jet nozzle has a droplet shape corresponding to the shape of the fine powder of the desired shape. Is placed into position.

Then, the liquid is sprayed through the liquid jet nozzle 134 to cool the droplet at the corresponding position to form a fine powder of a desired shape. At this time, the pressure of the liquid to be injected is adjusted to be 1bar to 1500bar.

Then, the fine powder formed through the liquid spray cooling is dropped to collect the fine powder in the collected fine powder collecting portion. (S150)

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific preferred embodiments described above, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

[Description of the code]

110: molten metal supply unit

120: gas injection unit

130: liquid jet

140: fine powder collecting unit

Claims

A molten metal supplier for melting a raw material to supply a molten metal;

A gas injector positioned below the molten metal supply unit and configured to inject a gas including an inert gas to pulverize the molten metal to form droplets;

A liquid injector disposed under the gas injector, controlling a position to be injected into the droplet formed by the gas injector, and injecting liquid to form fine powder; And,

A fine powder collecting portion in which the fine powder formed by the liquid ejecting portion is dropped;

Fine powder manufacturing apparatus comprising a.
The method of claim 1,

The temperature of the gas is 25 ° C to 750 ° C, the pressure of the gas is 1bar to 150bar fine powder manufacturing apparatus.
The method of claim 1,

The gas is a fine powder production apparatus containing at least one of nitrogen, argon.
The method of claim 1,

The gas injection unit includes a gas injection nozzle for injecting a gas containing the inert gas,

The liquid injection unit, fine powder manufacturing apparatus is installed spaced apart from the gas injection nozzle 1mm to 2000mm.
The method of claim 1,

The liquid is water or liquid nitrogen or liquid argon,

The liquid injection unit, a liquid storage unit for storing the liquid;

A liquid jet nozzle for injecting the liquid;

A liquid pressurizing unit for adjusting a pressure of the liquid to be sprayed through the liquid spray nozzle; And,

A liquid spray position adjusting unit for adjusting a vertical position of the liquid spray nozzle;

Fine powder production apparatus comprising a.
The method of claim 5,

The liquid jet nozzle is provided with two or more fine powder spaced apart from the predetermined distance around the falling droplets.
The method of claim 5,

The nozzle shape of the liquid jet nozzle is fine powder manufacturing apparatus comprising any one of a multi-nozzle, a hole nozzle, an open slit nozzle.
The method of claim 1,

The injection pressure of the liquid injection unit is a fine powder manufacturing apparatus of 1bar to 1500bar.
Melting the raw material to form a molten metal, and then discharging the molten metal;

Spraying an inert gas on the discharged molten metal to form droplets;

Adjusting the position of the liquid to be sprayed on the droplets; And,

Spraying liquid onto the droplets to cool the droplets to produce fine powder;

Fine powder production method comprising a.
The method of claim 9,

In the forming of the droplet, the inert gas is fine powder manufacturing method comprising at least one of nitrogen, argon.
The method of claim 9,

In the forming of the droplet, the temperature of the inert gas is 25 ° C to 750 ° C, the pressure of the inert gas is 1bar to 150bar fine powder manufacturing method.
The method of claim 9,

The liquid is water or liquid nitrogen or liquid argon, the pressure of the liquid is 1bar to 1500bar fine powder manufacturing method.
Fine powder produced by the fine powder manufacturing apparatus of any one of claims 1 to 8.
The fine powder produced by the method for producing a fine powder according to any one of claims 9 to 12.