JP2001039704A - Production of metal oxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a metal oxide small in particle size, uniform, and low in amorphous component by supplying a metal halide-containing gas to a reaction zone so as to obtain turbulent flow, allowing the gas to contact water generated by the combustion reaction of the fuel gas supplied separately and oxygen-containing gas to be subjected to hydrolyzing reaction by heating at a specified temperature. SOLUTION: A soln. of the metal halide (titanium tetrachloride, silicon tetrachloride, or the like) is evaporated by heating to 160-400 deg.C at an evaporator, and the obtained gaseous metal halide is mixed with an inert gas (nitrogen, or the like) in a mixing ratio (wt. ratio) of (0.5:1)-(5:1) and the mixture is supplied to the reaction zone at a speed of 30-300 m/sec in turbulent flow state or turbulent flow transition state. On the other hand, the water generated by the combustion reaction of the fuel gas (methane, ethane, or the like) supplied separately and the oxygen-containing gas is brought into contact with the gaseous metal halide at the reaction zone and hydrolyzed by heating at 400-1500 deg.C to produce the metal oxide (titanium oxide or the like).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanium oxide having a small and uniform particle size and a small amount of non-crystalline components by jetting a metal halide in a gas phase at a high speed and subjecting it to a hydrolysis reaction by heating. And metal oxides such as silicon oxide, aluminum oxide, and tin oxide, and a method for industrially advantageously producing these composite metal oxides. More specifically, the present invention relates to a method for producing a metal oxide having high photocatalytic activity, a metal oxide for a catalyst carrier having high heat resistance, and a metal oxide having excellent ultraviolet shielding ability. Among the metal oxides, particularly, in the case of titanium oxide, those having fine particles having an average particle diameter of 0.1 μm or less have higher ultraviolet absorbing ability than titanium oxide for pigments having a larger particle diameter and have transparency, Conventionally, it has been used as an ultraviolet shielding agent for cosmetics and paints, but recently its use of its excellent photocatalytic activity has attracted attention. Here, the term titanium oxide refers to titanium oxide such as titanium monoxide, dititanium trioxide, titanium dioxide, and titanium peroxide. In particular, in the case of titanium dioxide, even if the crystal form is rutile, anatase It may be in shape.

[0002]

2. Description of the Related Art A method for producing a metal oxide by causing a metal halide gas to undergo a hydrolysis reaction simultaneously with combustion in or near a flame formed by combustion of a fuel,
It is conventionally known as a flame hydrolysis method. When the fuel burns, water is formed and this water is used for the reaction. As such a fuel, a hydrogen-containing combustible gas such as hydrogen or a hydrocarbon compound is usually used.

In Japanese Patent Publication No. 36-3359, a halogen compound, a combustion gas and an oxygen-containing gas are mixed uniformly beforehand, and the mixed gas is supplied to a reaction zone from a nozzle of a burner at a lower portion of a reaction chamber. A method of burning and reacting is disclosed. In this method, the halogen compound is diluted with the combustion gas, and the collision between the generated oxide particles is suppressed, and the growth and aggregation of the particles are prevented, so that fine particles are easily obtained. Further, since the halogen compound and the fuel gas are supplied to the reaction zone from the burner nozzle in a uniformly mixed state, even if the flame formed by the combustion of the fuel gas becomes relatively large, it depends on the place where the reaction occurs. Particles having a uniform particle size can be easily obtained. However, in this method, it is necessary to operate so that the flame does not become turbulent or eddy, so as to suppress collision between particles. Further, if the supply of the mixed gas from the burner nozzle is too fast, the flame blows out. If the supply is too slow, flashback occurs, so that it is difficult to adjust the supply speed. Further, since the halogen compound acts as a combustion inhibitor, there are many problems such as the need for a large amount of fuel gas.

[0004] Japanese Patent Publication No. 31-6307 discloses that a mixed gas of a metal chloride and an oxygen-containing gas is brought into contact with a flame generated by the combustion of a combustible gas to cause the metal chloride to react with a combustion inhibitor. A solution to this problem is disclosed. However, in order to obtain uniform particles with this method,
It is necessary to supply the mixed gas in a thin layer having a thickness of about 1 cm, and when the apparatus is upsized, it is necessary to use many small flames.

[0005] Further, in any of the techniques, since the flame is in the reaction zone or the flame and the reaction zone are very close to each other, the characteristics of the generated metal oxide particles are easily affected by the combustion state of the flame. In these conventional techniques, in order to obtain a uniform metal oxide, it is necessary to adjust the flame of combustion to a laminar flame in order to suppress collision of generated particles and prevent sintering. However, in flame hydrolysis, combustion in a laminar flame is not necessarily industrially advantageous, but rather has problems. For example, when a laminar flame is used, the metal oxide easily adheres and crystallizes around the burner nozzle opening, and some kind of adhesion prevention measure is required. In addition, when the apparatus is increased in size, when a hydrocarbon compound is used as a combustion gas, an incompletely combusted hydrocarbon is generated, and the generated metal oxide particles are colored black or gray. The use of hydrogen as a fuel gas does not cause such a problem, but is more disadvantageous in handling and cost than hydrocarbons.

[0006]

DISCLOSURE OF THE INVENTION The present invention overcomes the above-mentioned problems of the prior art, and has a small and uniform particle size.
Provided is a method capable of industrially advantageously producing a metal oxide having a small amount of non-crystalline components, particularly a metal oxide having high photocatalytic activity, a metal oxide for a catalyst carrier having high heat resistance, and a metal oxide having excellent ultraviolet shielding ability. It was done for.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, if a certain amount of water and a high temperature can be secured in the reaction zone, it is particularly necessary to use a flame as a laminar flow flame. Rather, the turbulent flame or turbulent transient flame is caused, and the supply rate of the metal halide-containing gas to the reaction zone is increased so that the metal halide-containing gas is turbulent or turbulent. By making it a transient state,
Based on the knowledge that the contact with water generated by combustion is further improved, and as a result, the residence time of the generated metal oxide in the reaction zone is shortened, and fine metal oxides are obtained industrially advantageously. Thus, the present invention has been completed. That is, a metal halide-containing gas is supplied to a reaction zone in a turbulent state or a turbulent transient state, and is brought into contact with water generated by a combustion reaction between a separately supplied fuel gas and an oxygen-containing gas to form a 400 μm. This is a method for producing a metal oxide, wherein the metal oxide is heated and hydrolyzed at a temperature of about 1500 ° C.

[0008]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a metal halide-containing gas is first supplied to a reaction zone in a turbulent state or a turbulent transient state. The turbulent state is a state in which the Reynolds number at the supply port of the metal halide-containing gas is about 3000 or more.
It is in a state of 300 to 3000. The reaction zone is a zone from the start of the hydrolysis reaction of the metal halide to the end of the formation of the metal oxide particles, and the reaction zone in the present invention is considered to be substantially in the combustion zone. The metal halide-containing gas can be supplied, for example, by providing a burner nozzle below the reaction zone. The metal halide-containing gas can be obtained, for example, by heating a metal halide solution to a temperature of 160 to 400 ° C. with an evaporator and evaporating the solution. In the case of obtaining a composite metal oxide using a plurality of metal halides, the mixed gas containing a metal halide may be obtained by: 1) heating a solution in which a plurality of metal halides are mixed in advance by an evaporator to evaporate;
2) heating each metal halide in a separate evaporator,
It can be obtained by evaporating each gas containing a metal halide and mixing the obtained gases. In the present invention, as the metal halide-containing gas, when evaporating the metal halide solution, an inert gas is supplied to form a mixed gas of the metal halide gas and the inert gas, and the mixed gas is supplied to the reaction zone. It is desirable to supply. By supplying the inert gas, the metal halide gas is diluted, and the collision between particles is suppressed, so that fine particles are easily obtained. Further, by mixing the inert gas when evaporating the metal halide, there is an advantage that the metal halide can be gasified at a lower temperature. As the inert gas, nitrogen, helium, argon, carbon dioxide, or the like can be used, and nitrogen gas is particularly desirable. The mixing ratio between the metal halide and the inert gas is usually 0.5: 1 to 5: 1 (weight ratio).

The metal halide used in the present invention includes titanium tetrachloride, silicon tetrachloride, aluminum chloride, tin tetrachloride, phosphorus trichloride and the like. In particular, titanium oxide obtained using titanium tetrachloride is preferable because it has a small amount of non-crystalline components and excellent photocatalytic activity.

[0010] Further, in order to modify the physical properties of the produced metal oxide, the metal halide-containing gas used in the present invention may be a metal halide containing a different metal species such as aluminum, silicon, iron or antimony. 1 compound gas
A mixed metal oxide in which these different metal oxides are solid-dissolved in the metal oxide may be obtained by appropriately mixing seeds or more and subjecting them to heat hydrolysis by the above method. In particular, when a gas obtained by mixing a silicon tetrachloride gas and / or an aluminum chloride gas with a titanium tetrachloride-containing gas as a metal halide is used, the resulting silicon and / or aluminum and the composite metal oxide of titanium have heat resistance performance. It is preferable as a high metal oxide for a catalyst carrier and a metal oxide excellent in ultraviolet shielding ability.

[0011] The composition of silicon and / or aluminum and titanium in the composite metal oxide can be appropriately set according to the application. As the amount of aluminum increases, the ability to block ultraviolet rays improves, and the transparency in the visible region can be improved. At the same time, the presence of aluminum during the thermal hydrolysis of titanium tetrachloride has the effect of promoting the crystal form of the generated titanium oxide from anatase to rutile, which can suppress photocatalytic activity, and is a transparent cosmetic product utilizing ultraviolet shielding ability. It is useful for applications.
Further, as the amount of silicon increases, the heat resistance performance improves, and it becomes suitable for use as a catalyst carrier. In the present invention, the composition ratio of silicon and / or aluminum and titanium in the composite metal oxide, that is, the composition ratio of silicon and titanium, the composition ratio of aluminum and titanium, or the combination of silicon and aluminum and titanium In terms of the composition ratio, the composition is preferably 1 to 20/99 to 80 (molar ratio). In particular, when the composite metal oxide of the present invention is used for ultraviolet shielding, it is more preferably 5 to 20/95 to 80 (molar ratio) in terms of the composition ratio of aluminum and titanium in the composite metal oxide. Further, when the composite metal oxide of the present invention is used as a catalyst carrier, the composite metal oxide has a composition ratio of silicon, aluminum and titanium of 2 in the composite metal oxide.
~ 7/2 ~ 10/96 ~ 83 (molar ratio) is more preferable.

By supplying the metal halide-containing gas to the reaction zone in a turbulent state or a turbulent transient state, water produced by a combustion reaction between a fuel gas and an oxygen-containing gas, which will be described later, Good contact with the halide-containing gas. In particular, when the gas containing metal halide is 3
It is preferable to supply the mixture to the reaction zone at 0 to 300 m / sec because a favorable turbulent state or a turbulent transition state state can be obtained.

Next, the metal halide-containing gas is brought into contact with water generated by a combustion reaction between a separately supplied fuel gas and an oxygen-containing gas to be heated and hydrolyzed to obtain the metal oxide of the present invention. As the fuel gas, any hydrocarbon compound gas such as methane, ethane, propane, butane, pentane or the like, or hydrogen gas or any other gas that generates water by combustion can be used. Further, as the oxygen-containing gas, oxygen, air, or a mixed gas thereof, a mixed gas of an inert gas and oxygen, or the like can be used.

In the present invention, the state of the flame due to the combustion of the fuel gas may be any of a laminar flame, a turbulent flame, and a turbulent transient flame, but a turbulent flame or a turbulent transient flame is particularly preferred. . By making it a turbulent flame or a turbulent transient state flame, the contact between the water generated by combustion and the metal halide-containing gas becomes even better, the heating hydrolysis reaction proceeds quickly, and the fine metal particles An oxide can be obtained. A turbulent flame or a turbulent transient state flame means that the oxygen-containing gas has a Reynolds number of about 2500 to 3500 at a supply port.
And a flame which is burned together with the combustion gas. To achieve such a combustion state, it is desirable to supply the oxygen-containing gas to the reaction zone at a speed of 8 to 11 m / sec. If the supply speed is slower than the above range, the flame length will be longer, and carbon of incomplete combustion will be more likely to be generated,
If it is too fast, it will blow out.

In the present invention, the supply of the metal halide-containing gas, the fuel gas and the oxygen-containing gas to the reaction zone is as follows:
It is desirable to use a multi-tube burner commonly used in flame hydrolysis. In this type of burner, generally, a metal halide-containing gas is supplied from the innermost single-tube nozzle at a speed of 1 to 20 m / sec. 1 to 1
At a speed of 0 m / sec, fuel gas is supplied to the reaction zone at a speed of 0.3 to 0.6 m / sec from the nozzle of the outermost triple pipe to form a laminar flame in the reaction zone and burn. And a hydrolysis reaction. However, in the present invention, the metal halide-containing gas is supplied from the first tube nozzle so as to be in a turbulent state or a turbulent transient state, and the fourth tube nozzle is provided outside the third tube nozzle. Is provided, and an oxygen-containing gas for supporting fuel is supplied to the reaction zone from the nozzle. Water generated by a combustion reaction between the oxygen-containing gas supplied from the second and fourth pipe nozzles and the fuel gas supplied from the third pipe nozzle, and the water generated from the first pipe nozzle The supplied metal halide-containing gas comes into contact with the gas, and a metal oxide is generated by a heating hydrolysis reaction. In the quadruple tube burner used in the present invention, it is preferable that the cross section of each nozzle is a perfect circle and the center line of each nozzle is coaxial, since the gas flow rate becomes uniform. In the present invention, this is called a concentric quadruple tube burner.

By supplying the oxygen-containing gas from the nozzle of the second tube, it is possible to prevent the attachment and precipitation of the whisker-like metal oxide on the burner nozzle surface. For this purpose only, an inert gas may be used instead of the oxygen-containing gas, but it is desirable to use an oxygen-containing gas that acts as a combustion aid. Further, the gas supplied from the nozzle of the second pipe also acts as a barrier to prevent mixing of the metal halide-containing gas of the first pipe and the fuel gas of the third pipe near the nozzle. .

By supplying the metal halide-containing gas to the reaction zone in a turbulent state or a turbulent transient state from the nozzle of the first tube, the moisture in the reaction zone generated by the combustion of the fuel gas is rapidly reduced. And a metal oxide having a uniform small particle diameter can be obtained. The supply speed is not particularly limited as long as it is in a turbulent flow or a turbulent transient state, but is preferably in a range of 30 to 300 m / sec. If the supply speed is higher than the above range, the pressure loss at the nozzle portion becomes large, which is not preferable in terms of the durability of the apparatus, and if it is low, it becomes a laminar flow state, and the high-temperature residence time becomes longer and the generated particles become larger, which is not preferable. . The feed speed from the first tube nozzle to the reaction zone is the diameter of the first tube nozzle or
It is controlled by changing the diameter of the nozzle tip.

It is desirable that the supply speed of the fuel gas supplied from the nozzle of the third tube to the reaction zone is usually 0.3 to 0.6 m / sec. As a result, uniform reaction is likely to be hindered by the air supplied from the nozzle of the fourth tube, and if it is fast, the flame due to the combustion of the fuel is blown out and the combustion is easily stopped. Further, it is desirable that the state of the flame due to the combustion of the fuel gas be a turbulent flame or a turbulent transient flame as described above.

The oxygen-containing gas for supporting the fuel supplied from the fourth tube nozzle is a fuel gas supplied from the third tube nozzle together with the oxygen-containing gas supplied from the second tube nozzle. Combustion reacts with to form a flame and produce water.

Further, the present invention is a method for producing a metal oxide, wherein the metal oxide produced by the heat hydrolysis reaction is separated using a filter. A bag filter, a ceramic filter, or the like can be used as the filter. When a bag filter is used, its heat-resistant temperature is about 200 ° C.
After once cooling the gas containing the metal oxide after the reaction at a high temperature of 900 ° C., the metal oxide is separated by a bag filter. The use of a ceramic filter is preferable because the heat resistance is higher than that of the bag filter, and the gas can be continuously operated without cooling the gas.

In the metal oxide obtained by the method of the present invention, the residence time in the high-temperature reaction zone is reduced by supplying the metal halide-containing gas to the reaction zone at a high speed, so that aggregation due to sintering is extremely small. As a result, fine particles having a smaller particle diameter than those of the prior art can be obtained. For example, in the case of the titanium oxide obtained in the present invention, the fine particles having an average particle diameter of 0.1 μm or less, particularly 0.04 μm or less, further having a small amount of non-crystalline components, and having anatase type crystals, It is highly active.

Next, the present invention will be described with reference to FIG.

The metal halide A (a) is quantitatively quantified by a feed pump (1) using a quartz glass evaporator A (2).
Feed to. If necessary, metal halide B (i)
And the evaporator B in which the inert gas (b) is preheated
Feed to evaporator A (2) via (6). The evaporator A is heated, where the metal halide is evaporated.
An inert gas (b) is supplied to the evaporator A in parallel with the metal halide, and the metal halide-containing gas is taken out in a mixed state with the inert gas. In the present invention, the burner is a concentric quadruple tube type (3), and the metal halide-containing gas (c) is supplied from the nozzle of the first tube to the fourth tube.
Oxygen-containing gas (d) from the nozzle of the heavy pipe,
(F), the fuel gas (e) is supplied from the nozzle of the third tube. The inner diameter of the innermost single tube nozzle was 20 mm, and the tip of the nozzle was squeezed to 2 to 4 mmφ to control the supply rate of the metal halide-containing gas. The metal halide-containing gas is supplied from this nozzle at a high speed of 30 to 300 m / sec in a turbulent state or a turbulent transient state (4).
To supply. The generated metal oxide particles are separated and collected using the filter (5).

[0024]

The present invention will be further described with reference to the following examples, which do not limit the present invention.

EXAMPLE 1 950 g of titanium tetrachloride was placed in an evaporator heated to 260 ° C.
/ Hour, nitrogen was supplied at 1200 Nl / hour as an inert gas to produce a titanium tetrachloride-containing gas of titanium tetrachloride / nitrogen = 1/10 (volume ratio).

The tip of a single-tube nozzle having an inner diameter of 20 mmφ is squeezed to 4 mmφ, and the above titanium tetrachloride-containing gas is supplied from the nozzle into the reaction chamber at a speed of 40 m / sec so as to be in a turbulent state. Air is supplied as oxygen-containing gas at 3000 Nl / h from the second nozzle and at 12,000 Nl / h from the fourth nozzle.
Propane was supplied at 380 Nl / h as fuel from the nozzle of the heavy pipe, a turbulent flame was formed in the reaction chamber, and the titanium tetrachloride was heated and hydrolyzed. Then, the residual gas was separated using a ceramic filter. And titanium oxide (sample A). In this case, the temperature of the reaction zone is 700 to 9
00 ° C.

Example 2 The tip of the nozzle in the first tube was squeezed to 2 mmφ,
Titanium oxide (sample B) was obtained under the same conditions as in Example 1, except that the titanium tetrachloride-containing gas was supplied into the reaction chamber at a speed of seconds so as to be in a turbulent state. At this time, the temperature of the reaction zone was 7
It was 00-900 ° C.

Comparative Example 1 A single tube nozzle having an inner diameter of 20 mmφ was used as it was,
A titanium tetrachloride-containing gas was supplied to the reaction chamber at a speed of 1.6 m / sec so as to be in a laminar flow state, a laminar flame was formed in the reaction chamber, and the titanium tetrachloride was heated and hydrolyzed. Titanium oxide (sample C) was obtained under the same conditions as in Example 1. At this time, the temperature of the reaction zone was 750 to 950 ° C.

Evaluation 1 The specific surface area of each of the samples A to C was measured using a flowsorb model 2300.
It measured using the fluid type specific surface area automatic measuring device (made by Shimadzu Corporation). The particle diameter was calculated from the measured specific surface area by the equation (1). Formula (1) d = 6 / (ρ × s) d = particle diameter (μm) ρ = density 3.8 (g / cm ³ ) s = specific surface area (m ² / g) And a spectrophotometric diameter of U-3200
It was measured as soluble TiO ₂ using a mold (manufactured by Hitachi, Ltd.). The results shown in Table 1 were obtained by the above evaluation.

[0030]

[Table 1]

Evaluation 2 Samples B and C and commercially available ultrafine titanium dioxide P-25
(Degussa) was evaluated for its photocatalytic activity by its acetaldehyde decomposition activity. The acetaldehyde concentration was measured using gas chromatography GC-14A (manufactured by Shimadzu Corporation). Table 2 shows the obtained results.

[0032]

[Table 2] * Acetaldehyde decomposition reaction rate constant

Example 3 (Ti / Al system) Titanium tetrachloride was added to an evaporator heated to 300 ° C.
g / hour, 25Nl /
At this time, nitrogen was supplied at 1200 Nl / hour as an inert gas, and titanium tetrachloride / aluminum chloride / nitrogen =
A gas containing 4/1/49 (volume ratio) titanium tetrachloride and aluminum chloride was produced. The aluminum chloride gas was obtained by placing 700 g of aluminum chloride in a 1.3-liter quartz glass container, and heating and vaporizing the container with a heater so that the outlet temperature of the container was 130 ° C. while flowing nitrogen gas through the container. Was.

The tip of the single-tube nozzle having an inner diameter of 20 mmφ is squeezed to 2 mmφ, and the above gas containing titanium tetrachloride and aluminum chloride is reacted at a speed of 160 m / sec from the nozzle so as to be in a turbulent state. Air is supplied into the room and air is supplied as oxygen-containing gas at 3000 Nl / h from the second nozzle and 1200 Nl / h from the fourth nozzle, and propane is supplied as fuel from the third nozzle. At 380 Nl / hr, a turbulent flame is formed in the reaction chamber to cause a hydrolysis reaction of titanium tetrachloride and aluminum chloride, and then a residual gas is separated using a bag filter. An oxide (sample D) was obtained. In this case, the temperature of the reaction zone was 700 to 1000 ° C. The composition of sample D was Ti /
Al = 81/19 (molar ratio) and the specific surface area was 48 m ² /
g, crystalline form: 82% for rutile form, 18% for anatase form
Met.

Example 4 (Ti / Al system) In Example 3, 901 g / hour of titanium tetrachloride, 9 Nl / hour of aluminum chloride gas, and 1200 Nl / hour of nitrogen as an inert gas were supplied. The treatment was performed in the same manner as in Example 3 except that a gas containing titanium tetrachloride and aluminum chloride in a volume ratio of titanium / aluminum chloride / nitrogen = 12/1/133 (volume ratio) was produced. A composite metal oxide of titanium and aluminum (sample E) was obtained. still,
At this time, the temperature of the reaction zone was 700 to 1000 ° C. Sample E had a composition of Ti / Al = 93.1 / 6.9 (molar ratio), a specific surface area of 45.5 m ² / g, a crystal form of 67% of rutile form and 33% of anatase form.

Evaluation 3 Samples D and E obtained in Examples 3 and 4 and a comparative sample were coated with commercially available ultrafine titanium dioxide P-25 (manufactured by Degussa Co., Ltd.) with the following compositions, respectively, on a triacetate film. Was applied using a doctor blade to form a coating film. Sample 0.03 g Liquid paraffin 1.2 g Vaseline 0.81 g Stearic acid 0.03 g The transmittance of the obtained coating film at a wavelength of 300 to 550 nm was measured with a spectrophotometer (Shimadzu UV-240, manufactured by Shimadzu Corporation). . The results are shown in Table 3. From Table 3, it can be seen that the composite metal oxide of titanium and aluminum of the present invention has a high ultraviolet shielding ability in a UVB wavelength region (300 nm) and a UVA wavelength region (350 nm) and a high transparency in a visible light region (550 nm). I understood.

[0037]

[Table 3]

Evaluation 4 The coating color (L, a, b) before black light irradiation and the coating color (L ′, a ′) one hour after irradiation of the coating film used in Evaluation 3 above were evaluated.
b ') is a color difference meter (Z-1001DP, manufactured by Nippon Denshoku Industries)
And the change in the coating color before and after black light irradiation [ΔE = √ ((LL ′) ² + (a−a ′) ² + (b−
b ′) ² )] was determined and shown in Table 4. From Table 4, the composite metal oxide of titanium and aluminum of the present invention has a small ΔE,
It was found that the photocatalytic activity was suppressed.

[0039]

[Table 4]

Example 5 (Ti / Si system) Titanium tetrachloride was added to an evaporator heated to 260 ° C.
g / h, 33 g / h of silicon tetrachloride, 1200 Nl / h of nitrogen as an inert gas, and titanium tetrachloride / silicon tetrachloride / nitrogen = 1 / 0.03 / 10 (volume ratio)
A gas containing titanium tetrachloride and silicon tetrachloride was produced.

The tip of a single-tube nozzle having an inner diameter of 20 mmφ is squeezed to 2 mmφ, and the above-mentioned gas containing titanium tetrachloride and silicon tetrachloride is turbulent from this nozzle at a speed of 160 m / sec. Air is supplied into the reaction chamber and air is supplied as oxygen-containing gas at 3000 Nl / h from the second nozzle and 15,000 Nl / h at the fourth nozzle.
At the same time, propane was supplied as fuel from the third nozzle at 380 Nl / hour, and a turbulent flame was formed in the reaction chamber to cause the titanium tetrachloride and silicon tetrachloride to undergo a hydrolysis reaction. Thereafter, the residual gas was separated using a ceramic filter to obtain a composite metal oxide of titanium and silicon (sample F). The temperature of the reaction zone at this time was 70
0-1000 ° C. The composition of sample F was Ti / Si =
96.2 / 3.8 (molar ratio).
3.5% and the anatase form was 76.5%.

Example 6 (Ti / Si system) In Example 5, 886 g / h of titanium tetrachloride, 64 g / h of silicon tetrachloride and 12 g of nitrogen as an inert gas were used.
Example 5 except that a gas containing titanium tetrachloride and silicon tetrachloride was supplied at a supply rate of 00 N l / h and titanium tetrachloride / silicon tetrachloride / nitrogen = 1 / 0.06 / 10 (volume ratio). And do the same. A composite metal oxide of titanium and silicon (sample G) was obtained. The temperature of the reaction zone at this time was 700 to 1000 ° C. The composition of sample G is T
With i / Si = 92.6 / 7.4 (molar ratio), the crystal form was 19.4% for the rutile form and 80.6% for the anatase form.

Example 7 (Ti / Si / Al system) 827 g of titanium tetrachloride was placed in an evaporator heated to 300 ° C.
/ G, 67 g / h of silicon tetrachloride, 11 Nl / h of aluminum chloride, and 1200 g of nitrogen as an inert gas.
N liter / hour, titanium tetrachloride / silicon tetrachloride / aluminum chloride / nitrogen = 10 / 1.15 / 1/12
A gas containing 4 (volume ratio) titanium tetrachloride, silicon tetrachloride and aluminum chloride was produced.

The tip of a single-tube nozzle having an inner diameter of 20 mmφ is squeezed to 2 mmφ, and the gas containing titanium tetrachloride, silicon tetrachloride and aluminum chloride is discharged from this nozzle at a rate of 160 m / sec. At a speed of 3,000 liters / hour through the second nozzle as oxygen-containing gas.
Each was supplied at 2000 Nl / hour, and propane was supplied at 380 Nl / hour as fuel from the nozzle of the third tube to form a turbulent flame in the reaction chamber to thermally hydrolyze titanium tetrachloride and silicon tetrachloride. After the reaction, the residual gas was separated using a ceramic filter to obtain a composite metal oxide of titanium, silicon and aluminum (sample H). The temperature of the reaction zone at this time was 700 to 1000 ° C.
Met. The composition of sample H was Ti / Si / Al = 83.
At 8 / 6.7 / 9.5 (molar ratio), the crystal form was 53.5% for the rutile form and 46.5% for the anatase form.

Evaluation 5 The specific surface area (before and after SSA, before and after heat treatment of each of the samples F to H obtained in Examples 5 to 7 and the sample C obtained in Comparative Example 1 at a temperature of 1000 ° C. for 5 hours) ) Was measured to determine the heat shrinkage (= (before SSA-after SSA) / before SSA), and the results are shown in Table 5. As shown in Table 5, the composite metal oxide of silicon and / or aluminum and titanium of the present invention has a low heat shrinkage and is suitable for applications requiring heat resistance at high temperatures such as a catalyst carrier. I understood.

[0046]

[Table 5]

[0047]

As described above, according to the present invention, the high-temperature residence time is shortened by supplying the metal halide-containing gas to the reaction zone at a high speed, so that aggregation due to sintering is extremely small. Fine metal oxide particles having a small diameter can be obtained. Furthermore, titanium oxide obtained by the production method of the present invention using titanium tetrachloride as a metal halide has a small amount of non-crystalline components and high photocatalytic activity. Also,
The composite metal oxide of titanium and aluminum obtained by the production method of the present invention using titanium tetrachloride and aluminum chloride as metal halides has excellent UV shielding ability, high transparency in the visible light region, and photocatalytic activity. And is useful for sunscreen cosmetics and the like. Further, the composite metal oxide of aluminum and / or silicon and titanium obtained by the production method of the present invention using aluminum chloride and / or silicon tetrachloride and titanium tetrachloride as metal halides has a low heat shrinkage. It is excellent and is useful for applications requiring heat resistance at high temperatures, such as catalyst carriers.

[Brief description of the drawings]

FIG. 1 shows an apparatus configuration of the present invention.

[Explanation of symbols]

 (1) Feed pump (2) Evaporator A (3) Concentric quadruple tube burner (4) Reaction chamber filter Evaporator B (a) Metal halide A (b) Inert gas (c) Metal halide containing gas ( d) Oxygen-containing gas (for combustion / cleaning) (e) Fuel gas (f) Oxygen-containing gas (for combustion) (g) Exhaust gas (h) Metal oxide particles (i) Metal halide B

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yuji Ichida 1 Ishiharacho, Yokkaichi-shi, Mie Ishihara Sangyo Co., Ltd. (72) Inventor Daisuke Ito 1 Ishiharacho, Yokkaichi-shi, Mie Ishihara Sangyo F-term in Yokkaichi Office (reference) 4G042 DA01 DA02 DB09 DB10 DB11 DB21 DB22 DB24 DC03 DD08 DE04 DE16 4G047 CA02 CA05 CB04 CC01 CD07 4G069 AA02 AA03 BA03A BA03B BA04A BA04B BA48A BB04A BB04B05B16BBCBC BCBC BCB BCB BCB BCB BCB BC BC BD12C FA01 FB34 FB40 FC02

Claims (13)

[Claims] 1. A metal halide-containing gas is supplied to a reaction zone in a turbulent state or a turbulent transient state, and comes into contact with water generated by a combustion reaction between a separately supplied fuel gas and an oxygen-containing gas. A method for producing a metal oxide, which comprises causing a hydrolysis reaction by heating at a temperature of 400 to 1500 ° C. 2. The method according to claim 1, wherein the gas containing a metal halide is 30 to 300.
The method for producing a metal oxide according to claim 1, wherein the metal oxide is supplied to the reaction zone at a rate of m / sec. 3. A turbulent flame or a turbulent transient flame, wherein the flame generated by combustion of the fuel gas is adjusted.
The method for producing a metal oxide according to the above. 4. The method according to claim 1, wherein the oxygen-containing gas is supplied to the reaction zone at a speed of 8 to 11 m / sec. 5. A method for supplying a metal halide-containing gas, a fuel gas, and an oxygen-containing gas to a reaction zone by using a concentric quadruple tube burner, and supplying the metal halide-containing gas from the innermost single tube nozzle. 2. The metal oxide according to claim 1, wherein the oxygen-containing gas is supplied from the second pipe and the outermost fourth pipe nozzle, and the fuel gas is supplied from the third pipe nozzle. Manufacturing method. 6. The method according to claim 1, wherein the metal halide-containing gas is a mixed gas of a metal halide and an inert gas. 7. The method for producing a metal oxide according to claim 6, wherein the inert gas is nitrogen. 8. A method for producing a metal oxide, comprising separating the metal oxide obtained by the method according to claim 1 using a filter. 9. The method according to claim 8, wherein the filter is a ceramic filter. 10. The method according to claim 1, wherein the metal halide is titanium tetrachloride and the metal oxide is titanium oxide. 11. The method according to claim 1, wherein the metal halide is a mixture of two or more different metal halides, and the metal oxide is a composite metal oxide thereof.
The manufacturing method as described. 12. The method according to claim 1, wherein the metal halide is a mixture of silicon tetrachloride and / or aluminum chloride and titanium tetrachloride, and the metal oxide is a composite metal oxide of silicon and / or aluminum and titanium. The manufacturing method according to claim 11, wherein 13. The composition ratio of silicon and / or aluminum to titanium in the composite metal oxide is 1 to 20/9.
12. The composition according to claim 11, wherein the molar ratio is 9 to 80.
The manufacturing method as described.