JPH05286708A - Production of carbon-containing composition - Google Patents

Abstract

PURPOSE:To obtain a metal carbide by mixing a decomposable carbon compd. with a dispersion liquid of a metal oxide and introducing the mixture into a hat gas to obtain a carbon-contg. composition which is heated in an inert gas or in a gaseous nitrogen. CONSTITUTION:Air is continuously introduced into a reaction furnace shown in the figure from a duct 2 at 100Nm<3>/h, and a decomposable carbon compd. (e.g. gaseous propane) is supplied from a burner 3 in >=3 molar ratio of the compd. to a metal oxide to generate a hot gas current at 800-2000 deg.C in a spatial region 6 in the furnace. A dispersion liquid obtained by mixing and dispersing a metal oxide (e.g. silica powder of 99.5% purity) into A heavy oil by an agitator in 1:3 weight ratio of SiO2 to A heavy, oil is supplied into the furnace from a nozzle 4. The dispersion liquid is thermally decomposed to obtain a dispersoid, which is passed through a duct 5 and collected by a bag filter, etc., to obtain a carbon-contg. composition. The composition is heated to 1200-2000 deg.C in an inert gas atmosphere or in a nitrogen-contg. atmosphere, and the powder of the metal carbide or nitride is obtained.

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 fine and uniformly mixed carbon-containing composition containing a metal oxide and elementary carbon, which is suitable for producing a ceramic powder for sintering. More specifically, it relates to a method for producing a carbon-containing composition containing a metal oxide and elemental carbon, which is suitable for producing a metal carbide, a metal nitride, a metal carbonitride, a metal oxynitride and the like.

[0002]

2. Description of the Related Art As a method for producing a metal carbide powder which is useful as a raw material for a ceramic for sintering, there has been conventionally used a gas phase reaction between a hydrocarbon directly reduced by a carbon of a metal oxide and a hydrocarbon compound directly decomposable by a metal. Are known. As a method for producing the metal nitride powder, a method of heating a mixture of metal oxide and carbon to a high temperature in a nitrogen-containing compound (eg, nitrogen, ammonia) atmosphere Direct nitriding metal compound of metal and nitrogen-containing nitrogen such as ammonia Gas phase reactions with compounds are known.

Further, as a method for producing a metal carbonitride powder, the above-mentioned method is insufficient for converting a metal oxide into a metal carbide, but an excessive amount of carbon is required for converting into a metal nitride. There is known a method of converting the amount.

Further, as a method for producing a metal oxynitride powder, there is known a method in which, in the above-mentioned method, an amount of carbon which is insufficient for converting all of the metal oxide into a metal nitride is used. Has been. In producing ceramic powders such as metal carbides, metal nitrides, metal carbonitrides, and metal oxynitrides, a mixture of metal oxide and carbon is important as a raw material for producing these.

The obtained ceramic powder is usually formed into a sintered body. When the particles of these ceramic powders are fine, the particle size distribution is sharp and the purity is high when the sintered body is manufactured, the density of the sintered body tends to be high (hereinafter, this property is easily burned). (Called binding property) and the strength of the sintered body is increased.

In order to produce such a preferable ceramics powder, it is necessary to control the mixed state of the mixture of the metal oxide and the raw material thereof, taking the reaction mechanism into consideration. Conventionally, as a method for mixing metal oxide and carbon, generally, fine metal oxide powder and carbon powder are mechanically mixed using a kneader or a mixer.

However, in this method, since these powders are mechanically mixed with each other, the generation of dust is severe, the working environment is deteriorated, and impurities due to mechanical wear such as a kneader or a mixer are easily mixed. There is a problem.

Further, micron-sized fine metal oxide and carbon powders usually form secondary agglomerates, and the agglomeration force of such agglomerates is stronger. Therefore, even if the stirring power of the machine is maximized, the particles cannot be separated into single particles, and it is difficult to uniformly mix them. In addition, there is a density difference between the metal oxide and carbon. Therefore, there is an essential problem that it is very difficult to obtain a "homogeneous" mixture by mechanical mixing even if "fineness" is achieved.

In order to solve these problems, the present inventors, in Japanese Patent Publication No. 61-30613, introduce a decomposable metal compound and a decomposable carbon compound into a hot gas containing steam to decompose them. Then, a method for producing a desired mixture of metal oxide and carbon in a gas phase was proposed. According to the method,
It was possible to obtain a mixture in which fine metal oxide and carbon were uniformly mixed. By using the mixture, fine,
Moreover, a metal carbide having a sharp particle size distribution can be produced.

However, the decomposable metal compound used in this method has some drawbacks when used in industrial production as described below.

The first drawback is that these decomposable metal compounds are chemically highly active and therefore extremely difficult to handle. For example, there are problems that it is a flammable substance having a low flash point and produces toxic gas upon combustion, or it reacts with moisture in the atmosphere to produce mist of metal oxide. Therefore, in order to safely use these substances, explosion-proof equipment, fireproof structure, incidental equipment such as nitrogen filling is required, which increases the manufacturing cost.

The second drawback is that many of these decomposable metal compounds are expensive. The third drawback is that degradable metal compounds, such as TiCl ₄ and S, which are relatively inexpensive to obtain.
It generally contains chlorine, such as iCl ₄ or a part of which is substituted with a hydrocarbon group. Therefore,
The reaction for obtaining the desired carbon-containing composition has a problem that hydrochloric acid is produced as a by-product, or chlorine is produced depending on the reaction form. Therefore, a small amount of hydrochloric acid is mixed in the obtained mixture of metal oxide and carbon, and there is a problem that the hydrochloric acid corrodes the equipment in the subsequent steps. In addition, there is a problem in that a corrosive substance generated from a corroded device causes a fatal mixture of impurities in the final production of the easily sinterable ceramic powder. In order to prevent these, auxiliary equipment such as a corrosive component removing device, and equipment using a high-grade corrosion-resistant material in the subsequent process are required. Also, when chlorine gas is generated, it is necessary to pay sufficient attention to the safety of the working environment.

As described above, it is conventionally possible to provide a composition of a metal oxide and carbon suitable for producing an easily sinterable ceramic powder, but it is industrially safe. And it was difficult to manufacture at low cost.

[0014]

DISCLOSURE OF THE INVENTION The object of the present invention is to carry out no mechanical mixing operation such as a kneader or a mixer, which involves generation of dust and inclusion of impurities in a composition of metal oxide and carbon. In addition, the present invention is disclosed in Japanese Patent Publication No. Sho 61-306.
It is to provide a carbon-containing composition having a fine structure equivalent to that of the carbon-containing composition as described in Japanese Patent Publication No. 13 and a method for producing the carbon-containing composition safely and inexpensively. Furthermore, another object of the present invention is to provide a metal carbide powder,
And to provide a method for producing a metal nitride powder.

[0015]

Means for Solving the Problems In order to achieve the above object, the present inventors mix and disperse a metal oxide and / or a metal oxide which is converted into a metal oxide by heating into a decomposable carbon compound, By introducing into the hot gas, it is possible to obtain a carbon-containing composition in which fine metal oxides and carbon are uniformly mixed, and further, by heating the carbon-containing composition, fine and fine, and The inventors have found that an easily sinterable ceramic powder having a sharp particle size distribution can be obtained, and completed the present invention.

[0016] Therefore, the present invention is to introduce a dispersion liquid in which a metal oxide which is a decomposable carbon compound and / or a metal compound which is converted into a metal oxide by heating into a hot gas, is introduced into a hot gas to form a unitary carbon and a corresponding metal oxide. A method for producing a carbon-containing composition, which comprises producing a carbon-containing composition containing a substance and collecting the produced carbon-containing composition.

In the present invention, the decomposable carbon compound is a metal oxide and / or a metal compound which is converted into a metal oxide by heating is introduced into a dispersed dispersion hot gas to provide a simple carbon and a corresponding metal oxide. Is obtained, and then the carbon-containing composition is heated in an inert atmosphere.
Further, the present invention comprises a decomposable carbon compound, a metal oxide, and / or a metal compound which is converted into a metal oxide by heating, introduced into a dispersed dispersion hot gas to contain elemental carbon and a corresponding metal oxide. And a carbon-containing composition obtained by heating the carbon-containing composition in a nitrogen-containing atmosphere.

The present invention will be described in more detail. The decomposable carbon compound used in the practice of the present invention is capable of easily decomposing and producing simple carbon when introduced into hot gas, and is easily in a liquid phase state as it is, or easily by heating or cooling. Anything that can be in a liquid state can be used. For example,
Petroleum products such as gasoline, fuel oil, kerosene, light oil, heavy oil, benzene, styrene, C ₉ fraction mixture, petrochemical products such as ethylene bottom, tar products such as tar, pitch, creosote and naphthalene, Oils and fats such as linseed oil, stearic acid, and oleic acid are preferred, but are not limited thereto.

The metal oxides that can be used in the practice of the present invention are:
A wide range can be selected. Examples of such metal oxides include titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, boron, aluminum, silicon,
Examples include oxides of uranium and thorium. Specifically, SiO ₂ , TiO ₂ , WO ₃ , B ₂ O ₃ , Al ₂ O ₃ , MnO ₂ , Fe ₂ O ₃ ,
ZrO ₂ , HfO ₂ , UO ₂ , ThO ₂ , MoO ₃ , Cr ₂ O ₃ , VO ₂ , V ₂ O ₅ ,
A metal oxide such as Nb ₂ O ₅ or Ta ₂ O ₅ can be preferably used.

In the present invention, a metal compound which is converted into a metal oxide by heating can be used. Examples of such a metal compound include hydrates of the above metal oxides, hydroxides of the above metals, and powders of carbonates and oxalates of the above metals. Such a metal oxide and / or a metal compound which is converted into a metal oxide by heating are mixed and dispersed in a decomposable carbon compound to obtain a dispersion liquid. In this case, in the present invention, it does not matter if the metal oxide and / or the metal compound which is converted into the metal oxide by heating is not dissolved in the decomposable carbon compound in the carbon compound. In order to carry out the dispersion, there is no problem even if a method using an ordinary stirrer is used, but it is more preferable to use a stirrer having a high stirring and mixing ability such as a homomixer.

Further, in order to uniformly disperse the metal oxide and / or the metal compound which is converted into the metal oxide by heating in the decomposable carbon compound, a physical method such as using ultrasonic waves or a dispersant is decomposed. A chemical method such as addition to the organic carbon compound may be used in combination.

The particle size of the metal oxide in forming the dispersion and / or the metal compound converted to the metal oxide by heating is not particularly limited, but rather the kind of the compound, the price,
It is determined by the purity, dispersibility due to the specific gravity and viscosity of the decomposable carbon compound that is the base of dispersion, and the like.

The mixing ratio of the metal oxide and / or the metal compound which is converted into the metal oxide by heating and the decomposable carbon compound is such that the composition of the carbon-containing composition finally formed is carbon / metal oxide (mol-carbon / It needs to be considered because it directly affects the mol-metal oxide = abbreviated as molar ratio hereinafter). For example, when a specific example of producing a metal carbide from the obtained carbon-containing composition is represented by SiC and TiC, the reaction formula for forming the metal carbide is as follows: SiO ₂ + 3C → SiC + 2CO TiO ₂ + 3C → Since it is TiC + 2CO, it is necessary to control the mixing ratio so that the carbon-containing composition has a molar ratio of at least 3 or more, preferably 4 to 6.

What percentage of the decomposable carbon compound is obtained as elemental carbon depends on the kind of the decomposable carbon compound, reaction conditions,
Although it cannot be determined because it depends on the device characteristics, the carbonization rate is considered to be approximately 10 to 60%.

A reactor is used in the practice of the present invention. As a heating device for the space area in the furnace, a combustion burner, an electric heating element or the like is preferable. Further, an apparatus in which the reactor main body is provided with a nozzle for introducing the dispersion liquid, a duct for introducing hot gas, and a dispersoid discharge duct, and the inside of which is surrounded by a refractory material is preferably used.

There must be a space region within the reaction furnace capable of holding a temperature of at least 600 ° C. or higher, preferably 700 ° C. or higher, more preferably 800 ° C. or higher and 2000 ° C. or lower, and hot gas is formed in this region. To be done. When the temperature is higher than the above temperature, the decomposable carbon compound is decomposed to form simple carbon, and the metal compound which is converted into the metal oxide by heating is also converted into the metal oxide. The temperature inside the reaction furnace is 200
If the temperature exceeds 0 ° C, heat loss is usually caused, which is not preferable.

As a method for obtaining the hot gas, an energization heat generation method and a high frequency induction heating method can also be mentioned. In addition, the method of burning combustible substances such as methane, ethane, propane, kerosene, and gasoline with air is simple in terms of equipment and is economical in terms of thermal efficiency.

The temperature, flow rate and oxygen concentration of the hot gas thus obtained are determined by the particle size, specific surface area and bulk density of the finally obtained carbon-containing composition, and the molar ratio of elemental carbon-metal oxide. Is an important factor in determining.

It does not matter if the hot gas is non-oxidizing. However, in this case, it should be noted that the oil component in the decomposable carbon compound which could not be completely decomposed may be precipitated in the low temperature part of the furnace. The flow rate of hot gas and the oxygen concentration are nothing but the flow rate of oxygen, and thus the ratio of oxygen / decomposable carbon compound (kg-oxygen / kg-decomposable carbon compound), which determines the combustion amount of the decomposable carbon compound. Temperature is important as a factor and as a factor that determines the rate of thermal decomposition.

Although the details of the thermal decomposition mechanism of the decomposable carbon compound cannot be clarified, the specific surface area of the carbon-containing composition increases as the ratio of the oxygen flow rate to the decomposable carbon compound flow rate in the hot gas increases. However, the inventors have conducted an experiment that the bulk density of the obtained carbon-containing composition becomes small, and that the increase of the temperature of the hot gas gives the physical properties of the carbon-containing composition the same tendency as the increase of the oxygen flow rate. I have confirmed it.

The particle size of the metal oxide in the carbon-containing composition obtained in the reaction furnace does not always match the particle size of the metal oxide in the raw material dispersion liquid and / or the powder which becomes a metal oxide by heating. However, there is no difference in that the obtained carbon-containing compositions each have a structure in which the metal oxide and carbon are extremely finely and uniformly mixed.

The carbon-containing composition in the hot gas thus obtained is guided to the outside of the furnace and the solid matter contained therein is removed by using a known dust collector such as a bag filter, a cyclone, or an electrostatic precipitator. To collect. In order to reduce the heat load on the collector, it is preferable to cool them in advance.
As a cooling method, there is a method of using a heat exchanger or a method of directly injecting water. By injecting water directly,
The carbon-containing composition can be collected without using a special dust collector.

The carbon-containing composition obtained by the present invention can be used as it is for various purposes, but one of the most preferred uses is as a raw material for producing ceramic powder for sintering. A metal carbide or a composite metal carbide powder can be synthesized by heating the carbon-containing composition of the present invention at 1200 to 2000 ° C. in an atmosphere of helium, argon, nitrogen or the like. As described in Examples below, the carbide powder obtained by this method is highly pure, fine and easily sinterable.

The carbon-containing composition obtained by the present invention is placed in an atmosphere of a nitrogen-containing compound such as nitrogen or ammonia at 1200 to 2000 ° C.
The metal nitride, metal carbonitride, and metal oxynitride powder can be synthesized by heating at. As described in Examples below, the metal oxynitride powder obtained by this method becomes a readily sinterable powder.

[0035]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 Using the reaction furnace (inner diameter 600 mm, length 3 m) shown in FIG. 1, air was continuously introduced at 100 Nm ³ / h from a duct 2 and propane gas was introduced from a combustion burner 3 at 1 ．
Continuously supplied at 8 Nm ³ / h, burned, and 1100 to 15
A hot gas stream of 00 ° C. was generated in the space area 6 in the reactor. Next, the average particle size as a metal oxide (weight cumulative particle size distribution average particle size by centrifugal sedimentation method, D ₅₀ or less is the same)
Silica powder of 5.1 μm (purity 99.5%) was mixed with A heavy oil in a weight ratio of SiO ₂ : A heavy oil = 1: 3 by a stirrer, and the dispersion liquid was dispersed from a nozzle 4 at 40 kg / h. It was supplied into the furnace. The dispersion was supplied, and the dispersoid generated by thermal decomposition was cooled and then collected by a bag filter to obtain a carbon-containing composition of the present invention. The specific surface area of the obtained composition is 47 m.
^{It was 2} / g. This composition was dispersed in deionized water and filtered, and the amount of hydrochloric acid in the filtrate was quantified, but it was hardly detected. Further, the obtained composition was dried at 110 ° C. for 5 hours and its chemical composition was analyzed to find that it was 50.8% by weight of carbon, 49.0% by weight of SiO ₂ , and 0.2% by weight of others (carbon / The molar ratio of SiO ₂ is about 5.2). Further, the carbon-containing composition thus obtained was removed by combustion, and the specific surface area of the residual white powder was measured and found to be 380 m ² / g. The average particle size of silica and carbon is 0.3, respectively.
μm and 0.5 μm.

Example 2 A hot gas flow was generated under the same conditions as in Example 1, and titania powder having an average particle size of 3.5 μm (purity: 9 as metal oxide) was generated.
9.0%) to A heavy oil in a weight ratio of TiO ₂ : A heavy oil = 1:
40 kg of the dispersion liquid mixed and dispersed at a ratio of 2.8
/ H and fed into the furnace, and thermally decomposed to obtain a carbon-containing composition. The specific surface area (BET specific surface area according to a nitrogen adsorption report, the same applies hereinafter) was 58 m ² / g. The molar ratio of carbon to titanium dioxide in the resulting composition was about
It was 6.0. The carbon in the obtained carbon-containing composition was removed by burning, and the specific surface area of the titania powder was measured and found to be 332 m ² / g. Moreover, hydrochloric acid was not contained at all in this composition.

Example 3 The carbon-containing composition obtained in Example 1 was molded by a press molding machine and an apparent density of about 0.9 g / cm ³ was used in a high frequency heating furnace in an argon atmosphere. Heat at 1800 ℃ for 2 hours, once cool, then heat to 800 ℃ in air,
Excess elemental carbon was burned and removed to obtain powdery silicon carbide. It was confirmed by a powder X-ray diffraction method that the specific surface area of the silicon carbide powder was 12.4 m ² / g and the crystal shape was cubic. Further, when the metallic impurities of this silicon carbide were examined, the results were as shown in Table 1. 0.5 parts by weight of boron and 4 parts by weight of phenol resin to 100 parts by weight of this silicon carbide powder
When parts by weight were added and mixed and the mixture was molded by a press machine and sintered at 2100 ° C. in an argon atmosphere, the sintered density was 3.15 g / cm ³ .

[0039]

[Table 1]

Example 4 A hot gas flow was generated under the same conditions as in Example 1 to carry out metal oxidation.
Al having an average particle diameter of 0.5 μm_TwoO_Three Powder (pure
99.8%) to A heavy oil in a weight ratio of Al_TwoO _Three : A heavy
Oil = 1: 2.8 Mix and disperse the dispersion
It is supplied to the furnace at 40 kg / h and pyrolyzed to produce the carbon-containing material of the present invention.
An elementary composition was obtained. Al₂O₃The molar ratio of carbon to is 8.1
The specific surface area of this composition is 53m²/ g is also obtained
The carbon-containing composition was black, but burned out the carbon.
And white Al₂O₃Only remains, its specific surface area is about 31m²/ g
 Met .

Example 5 A hot oil flow was generated under the same conditions as in Example 1 and Al ₂ (OH) ₃ powder having an average particle diameter of 0.2 μm was used as A heavy oil as a metal compound powder which is converted into a metal oxide by heating. Al ₂ (O
H) ₃ : A heavy oil was mixed and dispersed at a ratio of 1: 2, and the dispersion liquid was supplied into the furnace at 40 kg / h and pyrolyzed to obtain a carbon-containing composition of the present invention. The specific surface area of the obtained carbon-containing composition was 69.
It was m ² / g, and the composition was black, but when the crystal phase was examined by X-ray diffraction, it was confirmed that the α-Al ₂ O ₃ phase was present. When carbon of the obtained composition was removed by burning, only white α-Al ₂ O ₃ remained, and its specific surface area was about 43 m ² / g.

Example 6 About 35 g of the carbon-containing composition obtained in Example 4 was placed on a flat plate made of high-purity graphite and heated at 1500 ° C. for 6 hours while flowing nitrogen gas at about 3 l / min. Then, excess carbon was removed by combustion. The obtained powder was grayish white and had a specific surface area of about 9.7 m ² / g. The X-ray diffraction image of this product is Al
Only N was shown, and no diffraction peak of Al ₂ O ₃ was observed. Also, the impurities of this AlN powder were measured, and Table 2
It became like.

[0043]

[Table 2]

10 g of the AlN powder thus obtained
Was placed in ethanol and 0.3 g of Y ₂ O ₃ powder was added thereto. The obtained slurry was mixed and dispersed by a ball mill and ethanol was evaporated on a hot plate. The powder mixture was molded into a disk having a diameter of 20 mm and a thickness of 7 mm at a pressure of ² ton / cm ² . This molded product was placed on a high-purity graphite dish and heated in a nitrogen stream at 1700 ° C. for 3 hours for sintering. The density of the obtained sintered body is 98.
It was 8%.

[0045] to obtain a raw material powder and mixed for 5 hours using a ball mill at a rate of Comparative Example 1 SiO ₂ powder (specific surface area 380 m ² / g) and carbon powder (specific surface area 120.4m ² / g) and a molar ratio of 5 It was This raw material powder was molded in exactly the same manner as in Example 3 and then heated in an argon atmosphere at 1800 ° C. for 2 hours using a high-frequency heating furnace, cooled once, and then heated in air to 800 ° C. to remove surplus elemental carbon. Burned off to obtain silicon carbide powder. This had a purity of 99.8 % . The specific surface area of the silicon carbide powder was 4.5 m ² / g, and the crystal shape was cubic. This silicon carbide powder was added and mixed with boron and a phenol resin in exactly the same manner as in Example 3, and what was molded with a press was sintered at 2100 ° C. in an argon atmosphere, and the sintered density was 2.80 g / cm ^3. Was less than.

Comparative Example 2 According to the method described in JP-B-61-30613, SiCl ₄ was used as the decomposable metal compound and A heavy oil was used as the decomposable carbon compound, and 25 kg / h and 20 k, respectively.
A carbon-containing composition was obtained by supplying the carbon-containing composition into the reaction furnace used in the present invention under the same conditions as in Example 1 except that the flow rate was g / h.

The specific surface area of the SiO ₂ powder in the carbon-containing composition was 470 m ² / g, and the molar ratio of carbon to silicon in the carbon-containing composition was 4.9. About 0.2% by weight of hydrochloric acid was contained in this carbon-containing composition.

Example 3 was conducted using the obtained carbon-containing composition.
By the same method as above, the sample was heated in an argon atmosphere at 1800 ° C. for 2 hours in a high frequency heating furnace. After cooling once, it was heated to 800 ° C. in air to sinter and remove excess carbon to obtain powdery silicon carbide. The specific surface area of the silicon carbide powder is 9.6.
m was ² / g. When the powder was observed with an electron microscope, it was found that whiskers were present to some extent in addition to the particles. In addition, when the silicon carbide powder was analyzed for impurities, it was as shown in Table 3. When this silicon carbide powder was sintered by the same method as in Comparative Example 1, the sintered density was 3.08 g / cm ³ .

[0049]

[Table 3]

[0050]

As described in detail above, according to the present invention, a metal oxide and / or a metal compound which is converted into a metal oxide by heating is mixed and dispersed in a decomposable carbon compound to prepare a dispersion liquid. By thermally decomposing the dispersion liquid in hot gas, a carbon-containing composition containing elemental carbon and the corresponding metal oxide can be obtained very efficiently. With respect to the properties of the carbon-containing composition produced by thermal decomposition, a homogeneous composition containing no impurities can be obtained, as compared with the conventional method obtained by mechanically mixing carbon powder and a metal oxide.

Further, according to the conventional method of introducing a decomposable metal compound and a decomposable carbon compound into a hot gas containing steam and thermally decomposing the composition, the decomposable metal compound used is chemically Since it is active, it has the drawback of being difficult to handle and expensive. In addition, there is a drawback that a corrosive compound such as hydrochloric acid is by-produced to corrode the apparatus and, at the same time, a corrosive compound such as hydrochloric acid remains in the target carbon-containing composition.

However, in the present invention, since the metal oxide powder is used as it is or the metal compound powder which is converted into the metal oxide by heating is used, it is industrially safe, inexpensive, and efficient, and has a desired carbon-containing composition. It has the feature that you can get things. Further, it has the advantage that it does not corrode the device and does not allow corrosive compounds to be present in the desired carbon-containing composition.

Further, the metal carbide powder and the metal nitride powder obtained by heating and reacting the carbon-containing composition are highly pure and fine, and have a great feature that they are powders suitable for sintering raw materials. Have The result is that these ceramic powders have the advantage of exhibiting easy sinterability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a reaction furnace used for carrying out the present invention.

[Explanation of symbols]

 1 reactor, 2 ducts, 3 combustion burners, 4 nozzles, 5 ducts, 6 space areas

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C04B 35/58 101 Z (72) Inventor Nobuyuki Sudo 1190 Kasamacho, Sakae-ku, Yokohama-shi, Kanagawa Prefecture Mitsuihigashi Pressure Chemical Co., Ltd. (72) Inventor Fumio Nakamura 1-6 Takasago, Takaishi City, Osaka Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Hiroshi Masuda 7-1-1 Hikoshimasako-cho, Shimonoseki City, Yamaguchi Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Sadakazu Kobara 7-1-1 Hikoshimasako-cho, Shimonoseki City, Yamaguchi Prefecture

Claims (3)

[Claims] 1. A metal oxide and / or a decomposable carbon compound.
Alternatively, a metal compound that is converted to a metal oxide by heating is introduced into a hot gas by introducing a dispersion liquid into a carbon-containing composition containing elemental carbon and a corresponding metal oxide, and the generated carbon-containing composition. A method for producing a carbon-containing composition, which comprises collecting the composition. 2. A metal oxide and / or a decomposable carbon compound.
Alternatively, a metal compound that is converted to a metal oxide by heating is introduced into a hot gas by introducing a dispersion liquid into a carbon-containing composition containing elemental carbon and a corresponding metal oxide, and then the carbon-containing composition. A method for producing a metal carbide powder, which comprises heating an object in an inert atmosphere. 3. A metal oxide and / or a decomposable carbon compound.
Alternatively, a metal compound that is converted to a metal oxide by heating is introduced into a hot gas by introducing a dispersion liquid into a carbon-containing composition containing elemental carbon and a corresponding metal oxide, and then the carbon-containing composition. A method for producing a metal nitride powder, which comprises heating an object in a nitrogen-containing atmosphere.