JPH05170420A - Production of metallic carbide powder - Google Patents

Abstract

PURPOSE:To decrease initial cost by spraying a metal (oxide) in reducing burning flame and by making the metallic vapor to react with a carbon source free radical in vapor phase. CONSTITUTION:An inert gas is supplied from a replacing gas supplying opening 64 into a reactor 62, a dilution gas is supplied from a supplying nozzle 72 into a transportation pipe 70 and a cyclone part 8 and a bag filter part 10 are replaced through a reactor part 6 by the inert gas with a high pressure blower part 12. Next, 1mol hydrocarbon gas and 0.5-0.9mol oxygen gas are supplied into a burner part 4 from the pipe lines 44, 46, are mixed, are injected to the reactor 62 and are ignited by a ignition device 68 to form reducing burning flame generating CO gas, H2 gas and the carbon source free radical of C and/or hydrocarbon. And the metal (oxide) in a hopper 22 is supplied through a table feeder 26, the dispersing nozzle 28 and the transportation tube 34 into the reducing burning flame to make the metallic vapor to react with the carbon source free radical in vapor phase and the metallic carbide is formed and is collected in the cyclone part 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a metal carbide powder, and more particularly to a method for producing a metal carbide powder utilizing a reducing combustion flame obtained by burning a mixed gas of hydrocarbon and oxygen.

[0002]

2. Description of the Related Art Metal carbide powder, for example, silicon carbide powder, is an industrially important material as a structural ceramic having excellent strength and corrosion resistance at high temperatures. It is used as an abrasive grain for grinding or polishing.

As a method for synthesizing such a carbide powder, there is known a method for synthesizing a carbide by injecting a metal powder into plasma to cause a vapor phase reaction between a generated metal vapor and a carbon-containing gas such as methane. There is. Since this method uses plasma, high temperature can be easily obtained, but it has many economical disadvantages such as high equipment cost and large electric power required for operation.

Therefore, industrially, a method is used in which metal and carbon or metal oxide and carbon are mixed and placed in a heat-resistant container such as a crucible and reacted at high temperature for a long time in an electric furnace. The method requires considerable equipment and labor for post-processing such as crushing and classification, and is not a simple method, and the cost is very high.

As another method for synthesizing the metal carbide, it is possible to use a chemical flame. Conventionally, the atmosphere of the chemical flame is an oxidizing atmosphere, and it is easy to synthesize an oxide. , It is difficult to apply to carbide.

As a method for synthesizing a powder using a chemical flame, for example, "Chemical Engineering" 46,524 as shown in (1982), H ₂ -O ₂ flame and C _X H _Y -O ₂ There is an example of supplying volatile metal halide to a flame to synthesize ultrafine oxide particles. The method using such a chemical flame has many industrial advantages such as a small initial cost for equipment and easy mass production, but the chemical flame is treated only as a high-temperature oxidizing atmosphere. Since a flame in a completely combusted state in which oxygen is mixed with a hydrocarbon at a theoretical mixing ratio or more is used, only an oxide can be synthesized by this method.

Further, Japanese Patent Laid-Open No. 60-255602 proposes a method for producing ultrafine oxide particles by charging metal powder into a burner. In this case, the burner is an auxiliary heat source for promoting the reaction. However, since the ultrafine particles are synthesized by the self-combustion reaction of the metal powder in the oxygen atmosphere, only the oxide can be synthesized.

[0008]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to use a novel synthesizing method in which a chemical flame method is applied to a carbide powder which has been difficult to synthesize by a conventional chemical flame method. Another object of the present invention is to provide a method for producing a metal carbide powder which can be produced continuously continuously, simply and inexpensively.

[0009]

The above-mentioned object is to provide a hydrocarbon gas and a reducing property for generating a carbon monoxide gas, a hydrogen gas and carbon and / or a carbon source radical of the hydrocarbon with respect to the hydrocarbon gas. A metal oxide or a metal oxide that forms a reducing combustion flame by mixing with an oxygen gas that causes a combustion reaction and then easily generates metal vapor in the reducing combustion flame by the action of the reducing combustion flame. A method for producing a metal carbide powder, characterized in that a raw material powder consisting of one or both of metal powders is sprayed together with an inert carrier gas, and the above carbon source radical and metal vapor are subjected to a gas phase reaction to obtain a metal carbide. Will be solved.

Preferably, the reducing combustion flame is formed in a state where it does not come into contact with a gas containing oxygen in the surroundings, and the metal carbide is discharged from the reducing combustion flame and then rapidly cooled and transported together with the combustion exhaust gas flow. Are collected and collected.

For example, the hydrocarbon gas is acetylene gas, the oxygen gas is mixed at a flow rate of 0.5 mol to 0.95 mol per mol of acetylene, and the raw material powder is silicon metal. is there.

[0012]

The gas phase reaction in the reducing combustion flame in the present invention is
A vaporized material or a thermal decomposition product of a raw material powder generated by the action of a reducing combustion flame and a carbon source such as a carbon radical or a hydrocarbon radical generated by the reducing combustion of a hydrocarbon gas react with each other at a high temperature to form a carbide. This carbide is rapidly cooled in the gas phase to form fine carbide powder.

Examples of the carbide powder obtained by the production method of the present invention include carbide powders of metals such as silicon, titanium and boron. As these raw materials for production, oxide powders or metal powders of the respective metals can be used. For example, when synthesizing silicon carbide (SiC), silicon dioxide powder (SiO2) or metallic silicon powder (Si) can be used.

These raw material powders are atomized and blown into the flame so that the temperature thereof is easily raised by the heat of the reducing combustion flame. Atomization is an operation in which the raw material powder is uniformly dispersed in a carrier gas, and this is performed by a powder feeder having a stirring blade, a table feeder, and a dispersion nozzle inside. The raw material powder finely disentangled by the stirring blade is quantitatively sent little by little to the dispersion nozzle by the table feeder, and is made into a mist state by the carrier gas blown from the dispersion nozzle at high pressure and high speed. The atomized raw material powder is pressure-fed to the burner through a transport pipe and ejected from the central portion of the burner into the reducing combustion flame. At this time,
If the particle size of the raw material powder is too small, the powders tend to agglomerate with each other to form large agglomerates, which may cause inconvenience in operation such that the temperature does not rise sufficiently in the reducing combustion flame or the transport pipe is clogged. On the contrary, if the particle size is too large, the heat capacity is large and the temperature does not rise sufficiently in the flame.
For this reason, the particle size of the raw material powder is restricted, so that it is 3 to 1
It is preferable to adjust to the range of 0 (μm).

On the other hand, as the type of carrier gas, since it does not affect the oxygen concentration in the reducing combustion flame, does not react with metal at high temperature, has a small heat capacity, and does not lower the temperature of the flame, it is like argon. It is preferable to use an inert gas. As the flow rate of the carrier gas increases, it is easier to atomize the powder and transport the powder in the transportation pipe, but if the flow rate is too high, the state of the reducing combustion flame is affected, which is not preferable. The flow rate is preferably adjusted to be equal to or less than the flow rate gas of hydrocarbons supplied to the burner, and more preferably adjusted to 1/2 or less. Further, it is preferable that the total orifice area of the dispersion nozzle is 0.1 (mm ² ) or less so that the gas can be atomized and transported with a gas flow rate as small as possible.

As the hydrocarbon gas used in the present invention, methane, ethane, propane, butane, ethylene, propylene, acetylene and the like can be used. Among these, acetylene having a high flame temperature is most preferable.
This is for the following reasons. Normally, the temperature of the outer peripheral part of the flame is lower than that of the inner part, so when reductive combustion is performed, the outer peripheral part is liable to generate soot, and the generated soot is mixed into the generated powder and becomes an impurity. There is a fear. Therefore, the use of a gas having a high combustion temperature such as acetylene is advantageous because the generation of soot is suppressed.

Since the present invention forms a reducing combustion flame by mixing a hydrocarbon gas and an oxygen gas, the reducing combustion flame in the present invention is an example in which acetylene gas is used as the hydrocarbon gas. 1) In the case of complete combustion, 2C2H2 + 5O2 → 4CO2 + 2H2O 2) In case of neutral combustion, in the case of C2H2 + O2 → 2CO + H2 3) In case of reducing combustion, C2H2 + mO2 → C + 2mCO + H2 + 2 ( 1-m) · C (0 <m <1), which indicates reductive combustion represented by three cases.

Therefore, when acetylene gas is used as the hydrocarbon, if the mixing ratio of oxygen gas is less than 1 mol per 1 mol of acetylene, carbon radicals of the carbon source are generated. Drops sharply,
The concentration of the carbon source in the flame becomes excessive and soot is mixed in the reaction product, that is, the metal carbide.

In the above-mentioned case, the acetylene gas which is preferable as the hydrocarbon gas has been described. However, regarding the hydrocarbon gas represented by CXHY as a general formula, the mixing ratio m of oxygen gas is the same as that of the above-mentioned acetylene gas. The burning flame is represented by CXHY + (X / 2) .O2 → X.CO + (Y / 2) .H2. Therefore, m <
Must be X / 2. In the present invention, the mixing ratio m of oxygen gas is adjusted in the range of 0.5 · (X / 2) <m <0.95 · (X / 2) ... (A).

The value of the mixing ratio m of the oxygen gas is adjusted within the range of the formula (A), as in the case of the acetylene gas of X / 2 = 1, as the mixing ratio m increases, the reaction of the present invention is performed. This is because the amount of generated carbon sources such as carbon radicals and hydrocarbon radicals directly related to the above is sharply reduced, and completely disappears at X / 2 or more.

On the other hand, when the mixing ratio m of the oxygen gas is too small, the temperature of the flame sharply drops and the concentration of the carbon source in the flame becomes excessive, so that it is mixed as soot in the reaction product.
Therefore, the mixing ratio m is preferably adjusted within the range of the above formula (A).

More importantly, the yield of the reaction may vary depending on the value of the mixing ratio m of oxygen gas. Therefore, in order to obtain a high yield, it depends on the kind of carbide to be synthesized and the kind of raw material used. It is preferable to finely adjust within the range of the above formula (A).

For example, when comparing silicon dioxide, which is used as a raw material when producing silicon carbide powder, with metallic silicon, the mixing ratio m is made smaller than that of metallic silicon because silicon dioxide contains oxygen. The higher the reducibility, the higher the yield.

In the present invention, since it is necessary to vaporize or thermally decompose the raw material powder in the reducing combustion flame, the temperature of the flame is adjusted to be higher than the vaporization or thermal decomposition temperature of the raw material powder. Depending on the type of hydrocarbon used and the mixing ratio of oxygen, the calorific value may be so small that it may not rise above the vaporization or thermal decomposition temperature. In such a case, it is advisable to perform auxiliary heating with an external heater to raise the temperature of the flame to the vaporization or thermal decomposition temperature or higher.

In the present invention, the feed amount of the raw material powder fed into the reducing combustion flame is adjusted by the table feeder in the powder feeder, but if the amount is too large, it will affect the flame temperature and yield. Therefore, considering the type and flow rate of hydrocarbons used, the mixing ratio of oxygen, the heat capacity of the raw material powder, the flow rate of the carrier gas, the amount of heat coming in and going out due to the gas phase reaction, the presence or absence of auxiliary heating, etc. The optimum amount is easily determined so that the phase reaction proceeds sufficiently.

In the present invention, importantly, the reducing combustion flame is formed in an oxygen-free atmosphere. When burning in an atmosphere containing oxygen, such as in the air, the flame has a double structure consisting of a non-oxidizing inner flame in the center and the outside air that diffuses and mixes. This is due to the inconvenience that the carbides made in 1) are oxidized while passing through the external flame. The oxygen-free atmosphere can be easily created by, for example, a device configuration in which a burner is attached to one end of the reaction vessel which is shielded from the outside air and the gas in the vessel is exhausted from the other end.

The carbide formed by the gas phase reaction in the flame is cooled rapidly to a powder when it goes out of the flame. This powder is guided to a dust collector such as a cyclone or a bag filter attached to the exhaust side of the reaction vessel together with the combustion exhaust gas, separated from the exhaust gas, and collected as a product.

In other words, according to the present invention, the gas phase reaction between the gas in the reducing combustion flame of a hydrocarbon formed in an oxygen-free atmosphere and the metal vapor of the raw material powder gasified by the heat of the flame Is a method for producing a metal carbide powder using
Taking the case of synthesizing silicon carbide powder using metallic silicon as a raw material, the powder is synthesized through the following process. First, the raw material metallic silicon powder is atomized in the powder feeder and blown into the flame together with the carrier gas. The atomized metallic silicon is easily vaporized by the heat and temperature of the flame and immediately reacts with carbon sources such as carbon radicals and hydrocarbon radicals during reductive combustion to form carbide powder of silicon, that is, silicon carbide. This can be collected by a dust collector into a product.

[0029]

EXAMPLES First, an apparatus for producing a metal powder carbide according to the present invention will be described. This manufacturing apparatus includes a powder feeder unit 2 for feeding raw material powder, a burner unit 4 connected to the powder feeder unit 2 and for supplying hydrocarbon gas and oxygen gas, and a burner unit 4 From the reaction container part 6 continuous from
It comprises a cyclone unit 8, a bag filter unit 10 and an exhaust blower unit 12 which are successively connected from the reaction vessel unit 6 for post-treatment. The powder feeder unit 2, burner unit 4, reaction container unit 6, cyclone unit 8, bag filter unit 10 and exhaust blower unit 12 are hermetically connected to each other to form one system.

The powder feeder 2 continuously supplies the hopper 22 for storing the powder raw material, the stirring blade 24 for stirring the powder raw material in the hopper 22, and the stirred powder raw material. It comprises a table feeder 26 and a dispersion nozzle 28 for dispersing the powder raw material. A motor 30 for driving the stirring blade 24 and the turntable feeder 26 is provided outside the hopper 22. A carrier gas supply pipe 32 is incorporated in the dispersion nozzle 28, and an inert high-pressure carrier gas, for example, argon gas is supplied to the dispersion nozzle 28 via the carrier gas supply pipe 32. The dispersion nozzle 28 is connected to the raw material powder transport pipe 34. 2 and 3 show enlarged views of the dispersion nozzle 28. As apparent from FIGS. 2 and 3, the dispersion nozzles 28 are arranged along the periphery of the turntable feeder 26 at a predetermined interval. Individual,
In the illustrated case, there are 12 pieces, and the high-pressure carrier gas is jetted from the carrier gas supply pipe 32 in the direction indicated by the arrow a in FIG. 2, and as shown by the reference sign b in FIG. The body is atomized.

The other end of the raw material powder transport pipe 34 is connected to the burner unit 4, and the burner unit 4 has a burner main body 42. One end of the burner main body 42 is carbonized together with the raw material powder transport pipe 34. Hydrogen supply pipe 44 and oxygen supply pipe 46
A flow rate controller (not shown) is attached to each of the raw material powder transport pipe 34, the hydrocarbon supply pipe 44, and the oxygen supply pipe 46. On the other hand, the other end of the burner main body 42 serves as a nozzle, which is hermetically connected to the reaction container section 6.

The reaction vessel portion 6 has a cylindrical reaction vessel 62 which is held in the vertical direction, and the end of the burner body 62 on the nozzle side is airtightly incorporated into the upper portion of the reaction vessel 62. And the replacement gas supply port 64 provided concentrically with the opening. Also, the reaction vessel 6 corresponding to the length of the flame from the burner section 4 during operation
An external heater 66 for auxiliary heating is attached to the outer peripheral portion of the second portion, and a spark discharge type ignition device 68 is also incorporated. The lower part of the reaction vessel 62 is a water-cooled double tube so as to withstand the high heat received from the flame. The reaction vessel 62 is connected to a transportation pipe 68, and a dilution gas ejection nozzle 72 for ejecting a dilution gas is inserted into the transportation pipe 70 at a position below the reaction vessel 62.

The other end of the transport pipe 68 is connected to a cyclone part 8 for collecting the synthesized metal carbide powder, and this cyclone part 8 is a water-cooled double pipe like the lower part of the reaction vessel 62. It also serves as a gas cooler. A bag filter unit 10 for collecting fine powder is connected to a downstream portion of the cyclone via a transportation pipe, and a high pressure blower unit 12 for exhaust is connected to the downstream side of the bag filter unit 10.

Next, the operation of the thus constructed carbide producing apparatus will be described.

First, from the replacement gas supply port 64 to the reaction container 6
An inert gas such as argon gas is flown into the chamber 2, and a diluent gas such as air or nitrogen is simultaneously poured into the transport pipe 70 from the diluent gas supply nozzle 72, and the high pressure blower unit 12 for exhausting the reaction gas from the reaction container unit 6 The gas in the system up to the cyclone unit 8 and the bag filter unit 10 is exhausted, whereby the gas in the system is gradually replaced with the inert gas.

Then, the hydrocarbon gas and the oxygen gas are supplied to the burner section 4 from the hydrocarbon supply piping 44 and the oxygen supply piping 46, respectively, and are premixed inside the burner section 4 and then jetted into the reaction vessel 62. It During operation, the flow rate and mixing ratio of each gas are accurately controlled by the mass flow controller so that they are always kept at preset values. The mixed gas ejected into the reaction container 62 is ignited by the ignition device 68 immediately after the ejection, and a reducing combustion flame is formed in the reaction container 62. When auxiliary heating is required, a predetermined electric power is applied to the external heater 66 before the gas is supplied.

Oxygen remaining in the reaction vessel 62 is gradually consumed by the action of this reducing combustion flame, and after a certain period of time, the inside of the reaction vessel 62 is reduced by the reducing gas generated from the mixed gas due to ignition. It is completely replaced by a reducing atmosphere consisting only of combustion gas and replacement gas.

The supply of the replacement gas from the replacement gas supply port 64 is continued during operation in order to protect the tube walls of the reaction vessel 62 and the transport tube 70 from heat, and is also supplied from the dilution gas jet nozzle 72. The injection of the dilution gas is also continued, whereby the reducing combustion gas is diluted so as not to cause an explosion in the cyclone unit 8 and the bag filter unit 10 where the gas is likely to stay. The flow rate is controlled by a flow meter and adjusted so that the concentration of the combustible gas generated by the reductive combustion is outside the explosion range.

After the gas in the reaction vessel 62 is replaced in this way, the atomized raw material powder is supplied from the powder feeder 2 into the reducing combustion flame through the raw material powder transport pipe 34. .. In the powder feeder unit 2, after the raw material powder filled in the hopper 22 is loosened by the stirring blades 24 inside, it is quantitatively supplied little by little by the table feeder 26 to the outlet of the dispersion nozzle 28. , Dispersion nozzle 2
By the high-pressure and high-speed carrier gas blown out from 8, the powder is very finely dispersed and atomized.

When the atomized raw material powder is blown into the reducing combustion flame, the raw material powder is vaporized or pyrolyzed by the heat of the flame and reacts with the gas in the flame in the gas phase to form a carbide powder.

Then, the carbide powder is sent to the cyclone unit 8 together with the gas through the transport pipe 70, where it is separated from the gas.
To be collected. The remaining fine particles that cannot be separated in the cyclone unit 8 are completely separated from the gas in the bag filter unit 12 in the subsequent stage and collected. The separated gas is discharged to the outside of the system through the exhaust high-pressure blower unit 12.

Specific examples of producing a carbide powder using such a carbide powder producing apparatus will be described below.

(Example 1) An example in which acetylene is used as a hydrocarbon gas to form a reducing combustion flame and silicon carbide powder is synthesized from metal silicon powder as a raw material powder is shown below. First, 50 argon gas is supplied from the replacement gas supply port 64.
(The standard state conversion flow rate per minute, liter, that is,
(Hereinafter, referred to as "Nl / min"), the gas is blown into the reaction vessel 62, while the dilution gas jet nozzle 72 blows 1
The gas was ejected at a flow rate of 000 (Nl / min), thereby performing gas replacement in the system.

Subsequently, acetylene gas and oxygen gas were supplied to the burner section 4 at flow rates of 20.9 (Nl / min) and 17.8 (Nl / min), respectively, and a reducing combustion flame was introduced into the reaction vessel 62. Formed. At this time, since the mixing ratio of oxygen gas in the above formula (A) is m = 0.85, carbon radicals and hydrocarbon radicals are generated in the flame by the reductive combustion of acetylene, and the flame is reductive. It is in a state.

A powder having an average particle diameter of 3.5 microns (μm) was used as the raw material metal silicon, and a carrier gas of argon was 9 (kilogram force per square centimeter, that is,
kgf / cm ² ) and a flow rate of 9 (Nl / min) to eject from the dispersion nozzle 28, and burner unit 4 at a rate of 3 (g / min).
Supplied to.

The flame temperature at this time is 2 according to the thermal equilibrium calculation.
It is 800 (° C). This temperature is higher than the vaporization temperature 2360 (° C.) of the metal silicon, and the metal silicon is easily vaporized. The produced silicon carbide powder was separated from the gas in the cyclone unit 8 and the bag filter unit 10 and collected.

The silicon carbide powder thus synthesized was evaluated by observation with a transmission electron microscope, measurement of adsorption specific surface area by the BET method, X-ray diffraction, EDS analysis and chemical analysis.

FIG. 4 shows an electron micrograph of the obtained silicon carbide powder. From this photograph and the measurement of the adsorption specific surface area, the obtained silicon carbide powder was a fine spherical powder having an average particle diameter of 50 nanometers (nm) and a specific surface area of 100 m ² / g.

FIG. 5 shows an X-ray diffraction pattern of the obtained silicon carbide powder. It is clear from the diffraction pattern of FIG. 5 that the obtained silicon carbide powder is silicon carbide having a β-type crystal form.

Next, the results of the chemical analysis are shown below. still,
For comparison, the measured values of the raw material powder are shown in parentheses. Fe 320ppm (610ppm) Co Less than 3ppm (less than 3ppm) Ni 41ppm (68ppm) Cr 75ppm (160ppm) Mn 10ppm (15ppm) Ti Less than 1ppm (2ppm) Zr Less than 1ppm (less than 1ppm) Thus obtained silicon carbide It can be seen that the impurities are less than in the raw material powder and the purity is higher.

Example 2 An example of synthesizing boron carbide powder from boron powder will be shown.

Since the carbide of boron is represented by the chemical formula of B 4 C and the ratio of carbon is smaller than that of silicon carbide of Example 1 described above, the mixing ratio m of oxygen gas is larger than that of Example 1 described above. And the mixing ratio is m =
It was set to 0.92. Further, the vaporization temperature of boron was 2550 ° C., and auxiliary heating was not performed because the reaction proceeds sufficiently by heating only the acetylene flame. The recovered powder has a particle size of 50
It was a fine spherical powder of .about.100 nanometer and was found by X-ray diffraction to be a carbide of boron represented by the chemical formula of B4 C.

[0053]

As described above, according to the method of the present invention, the carbonization source in the reducing combustion flame of hydrocarbons and the metal radicals of the raw material powder gasified by the heat of this reducing combustion flame It is possible to provide a method for producing a metal carbide powder capable of producing a metal carbide powder from a metal oxide powder or a metal powder by a gas phase reaction continuously in a very simple process, simply and inexpensively. Compared with the method using a furnace, the method of the present invention makes it possible to make the equipment extremely simple, and furthermore, the initial cost can be overwhelmingly reduced. Further, according to the method of the present invention, since the raw material powder is once gasified and subjected to a gas phase reaction, the reaction proceeds uniformly, and a fine powder can be obtained without passing through a pulverizing step,
Moreover, there are advantages such as high purity of the synthesized powder. Furthermore, since the combustion heat of inexpensive hydrocarbon gas is used as the main heat source, the operating cost can be very small, which is a great industrial advantage.

[Brief description of drawings]

FIG. 1 is a schematic system diagram showing an apparatus for producing a metal powder carbide according to the present invention.

FIG. 2 is a schematic view schematically showing in an enlarged manner the vicinity of a dispersion nozzle of the powder feeder unit of FIG.

FIG. 3 is a schematic view showing the dispersion nozzle of FIG. 2 from below.

FIG. 4 is an electron micrograph showing a particle structure of a silicon carbide powder obtained according to an example of the present invention.

5 is a graph showing X-ray diffraction of the silicon carbide powder obtained in FIG.

[Explanation of symbols]

 2 powder supply unit 4 burner unit 6 reaction container unit 8 cyclone unit 10 bag filter unit 12 high pressure blower unit 28 dispersion nozzle 32 carrier gas supply pipe 34 powder transport pipe 44 hydrocarbon supply pipe 46 oxygen supply pipe 72 dilution gas jet nozzle

Claims (3)

[Claims] 1. Oxygen at a ratio of causing a reducing combustion flame reaction to generate a hydrocarbon gas and a carbon monoxide gas, a hydrogen gas, a carbon and / or a carbon source radical of a hydrocarbon with respect to the hydrocarbon gas. Either a metal oxide or a metal that forms a reducing combustion flame by mixing with gas and ignites, and then easily generates metal vapor in the reducing combustion flame by the action of the reducing combustion flame. Alternatively, a method for producing a metal carbide powder, characterized in that a raw material powder consisting of both powders is sprayed together with an inert carrier gas, and the carbon source radical and the metal vapor are subjected to a gas phase reaction to obtain a metal carbide. 2. The reducing combustion flame is formed in a state where it does not come into contact with a gas containing oxygen in the surroundings, and the metal carbide is discharged from the reducing combustion flame and then rapidly cooled and transported together with a combustion exhaust gas flow. It is collected, The claim 1 characterized by the above-mentioned.
The method for producing the metal carbide powder according to item 1. 3. The hydrocarbon gas is acetylene gas, the oxygen gas is mixed at a flow rate of 0.5 mol or more and 0.95 mol or less with respect to 1 mol of acetylene, and the raw material powder is silicon metal. It exists, The manufacturing method of the metal carbide powder of Claim 1 or 2 characterized by the above-mentioned.