KR102044380B1 - Fabricating method of titania nano-particles - Google Patents

Abstract

The purpose of the present invention is to provide a method of manufacturing spherical pure anatase-type titania nanoparticles by generating a reactive plasma of 1,400 to 1,500°C using a microwave plasma reaction using electromagnetic wave discharge instead of a high temperature thermodynamic reaction, thereby reacting gas-phased titanium tetrachloride with the reactive plasma. The method of manufacturing titania nanoparticles comprises: a step (a) of preparing a mixed gas including oxygen gas and water vapor; a step (b) of forming the mixed gas into the reactive plasma of 1,400 to 1,500°C by using a microwave plasma generator; a step (c) of bringing gas-phased titanium tetrachloride (TiCl_4) into contact with the reactive plasma within a reaction furnace to form gas-phased titania; and a step (d) of cooling the gas-phased titania to form titania nanoparticles, wherein the titania nanoparticles are pure anatase-type titania nanoparticles with a sphericity or 0.9 or more.

Description

Method for manufacturing titania nanoparticles {FABRICATING METHOD OF TITANIA NANO-PARTICLES}

The present invention relates to a method for preparing tinania nanoparticles. Specifically, the present invention relates to a method for synthesizing pure anatase-type tania nanoparticles using a reactive plasma formed using a microwave plasma generator.

Titania material is neutral, stable in chemical properties, non-toxic, has strong chemical resistance against acids and alkalis, and has excellent weather resistance. Such titania is classified into rutile type and anatase type according to its constitution structure, and the manufacturing method is also classified into sulfuric acid method and chlorine method. Rutile type titania has higher refractive index and density than anatase type, and it is widely used as a high quality white pigment material because of excellent hiding power and pure white color. On the other hand, the anatase type is widely used as an electrode material or photocatalyst material using the electronic structure.

Among the titania manufacturing methods, the sulfuric acid method was first developed by the National Lead Company in 1919, and has been mainly used to prepare attaze-type titania using titanium sulfate as a precursor. Since then, due to environmental problems, the chlorine method, which has higher efficiency and lower byproducts than the sulfuric acid method, has been developed by Dupont and is widely used industrially. The chlorine method is mainly used for the production of rutile titania. Recently, the sulfuric acid method and the chlorine method account for 3: 7. In the chlorine method, titanium tetrachloride is used as a precursor, and titanium dioxide is produced through the following oxidation process. The oxidation process is carried out at an oxygen pressure of 900 ℃ to 1400 ℃, 2 bar to 3 bar, indirectly heating the mixture using a fuel, or by directly heating oxygen to react high temperature oxygen and TiCl ₄ as shown in the following reaction formula: Oxidation processes are widely used.

Scheme: TiCl ₄ + O ₂ → TiO ₂ + 2Cl ₂

In general, the spheronization method of titania is a method of synthesizing a spherical titania product from a precursor raw material and a method of obtaining a spherical final product through spheroidization without changing the composition from non-spherical titania powder. This can be. In the method of synthesizing spherical titania from the precursor raw material, a wet method or a vapor phase method is mainly used. For example, in the wet method, studies have been made to spheroidize by controlling conditions such as the use of a catalyst, a solvent, and a temperature selection in the process of producing titania by inducing hydrolysis and condensation reactions in a solution phase using an alkoxytitanium precursor. (Journal of Colloid and Interface Science, 334, 2009, 188-194). In addition, in the gas phase method, a method of vaporizing an alkoxytitanium or titanium tetrachloride precursor raw material and spheroidizing it through flame hydrolysis is known. For example, Japanese Patent Publication No. 3,993,956 discloses a method for preparing spherical titanium oxide fine particles by a gas phase method in which titanium tetrachloride is brought into contact with oxygen and hydrogen in a gas phase to oxidize. According to Japanese Patent Publication No. 3,993,956, 1 L of titanium tetrachloride gas is reacted at a ratio of 2 L to 20 L of oxygen and 0.3 L to 1.0 L of hydrogen, and the concentration of titanium tetrachloride in the reaction portion is 20% by volume in all gases. Hereinafter, it is disclosed that spherical titania having an average particle diameter of 0.01 μm to 5 μm is produced under conditions in which the oxygen concentration is 40% by volume to 80% by volume in all gases. At this time, the preferred reaction temperature is disclosed to 500 ℃ to 1,200 ℃.

In general, the selection of temperature is very important in controlling the appearance of titania. For example, the anatase form is produced at a low temperature of 700 ° C. to 800 ° C. as a metastable phase, and the rutile phase is formed at a high temperature of 800 ° C. or higher as the thermodynamic most stable titania. In addition, when anatase-type titania, which is metastable, is heated at a high temperature of 800 ° C. or more, phase transition easily occurs to rutile titania. Therefore, titania synthesized at a high temperature of 1,000 ° C. or higher is generally a rutile type or a mixed phase of rutile type and anatase type, and it is very difficult to form pure anatase type titania by flame hydrolysis at a high temperature of 1,000 ° C. or higher. In addition, since pure anatase-type titania has an angular shape by the rutile-type intrinsic crystal structure when it is transformed into a rutile form that is thermodynamically stable at high temperature, generally, a spherical titania is produced through high temperature treatment of 1,000 ° C. or higher. Is very difficult.

The present invention seeks to provide a method for producing spherical pure anatase type titania nanoparticles. Specifically, the present invention generates a reactive plasma of 1,400 ℃ to 1,500 ℃ by using a microwave plasma reaction using an electromagnetic discharge instead of a high temperature thermochemical reaction, and reacts titanium tetrachloride in the gaseous phase to form spherical pure anatase-type tania It is intended to provide a method for preparing nanoparticles.

One embodiment of the present invention, (a) preparing a mixed gas containing oxygen gas and water vapor; (b) forming the mixed gas into a reactive plasma at 1,400 ° C. to 1,500 ° C. using a microwave plasma generator; (c) in the reactor, contacting gaseous titanium tetrachloride (TiCl ₄ ) with the reactive plasma to form gaseous titania; And (d) cooling the gaseous titania to form titania nanoparticles.

The titania nanoparticles are pure anatase-type titania nanoparticles having a sphericity of 0.9 or more, providing a method for producing titania nanoparticles.

According to the present invention, the gaseous titanium tetrachloride may be formed by heating liquid titanium tetrachloride to 400 ° C. or higher.

According to the present invention, the temperature in the reactor may be 1200 ℃ to 1,500 ℃.

According to the present invention, step (d) may be to cool the titania in the gas phase through a cooling line provided with a cyclone trap at the end.

According to the present invention, the temperature of the cooling line is 15 ℃ to 25 ℃, the flow rate of the titania in the gas phase passing through the cooling line may be 25 L / min to 50 L / min.

According to the present invention, the volume ratio of oxygen gas and water vapor in the mixed gas may be 1: 1 to 10: 1.

According to the present invention, the supply flow rate of oxygen in the mixed gas may be controlled to 1 to 10 equivalents of the supply flow rate of the gaseous titanium tetrachloride.

The manufacturing method according to the exemplary embodiment of the present invention has an advantage of stably producing pure atanase-type titania nanoparticles.

1 is a schematic diagram of a device for implementing a method of manufacturing titania nanoparticles according to an embodiment of the present invention.
Figure 2 shows the XRD (X-Ray Diffraction) analysis results of titania nanoparticles prepared according to Examples 1, 2 and Comparative Examples 1, 2.
FIG. 3 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Example 1. FIG.
FIG. 4 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Example 2. FIG.
FIG. 5 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 1. FIG.
FIG. 6 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 2. FIG.
FIG. 7 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 3. FIG.
FIG. 8 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 4. FIG.
FIG. 9 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 5. FIG.
10 shows the results of XRD (X-Ray Diffraction) analysis of titania nanoparticles prepared according to Comparative Examples 3 to 5. FIG.

In the present specification, when a part "contains" a certain component, this means that the component may further include other components, except for the case where there is no contrary description.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

One of the methods used to make high temperature conditions in general oxidation reactions is the use of thermal plasma. Thermal plasma refers to a state in which high energy is applied to a gas and separated into electrons with positive charges and ions with positive charges, where electrons and ions are in equilibrium and generate high temperature heat. To create thermal plasma, electrical energy is commonly applied, such as direct current (DC) arc, ultra-high frequency inductively coupled discharge, and microwave, and thermal plasma may be classified according to these types of energy sources. In general, an inert gas such as argon or nitrogen, which has little chemical reactivity, is used as a gas generating plasma to minimize damage to an electrode used for generating energy. However, the microwave plasma corresponding to the electromagnetic plasma has an advantage that the electrode is not required, and the plasma generating unit and the electron beam generating unit are mainly separated into quartz tubes, thereby limiting the type of gas used for generating the plasma. For example, not only does the oxygen oxidatively reactive, air, and moisture cause damage to the electrode to be used as a reactive gas of direct current or inductively coupled discharge plasma, but some of the damaged electrode components may participate in the reaction and remain as impurities. have. Therefore, in the application of thermal plasma to the oxidation reaction, in case of using direct current or inductively coupled discharge plasma, inert gas which does not directly participate in the reaction generates plasma to generate heat and increases the temperature of the reaction gas by using this heat. It is common to use it. On the other hand, since the microwave plasma is not limited to the kind of reaction gas, there is an advantage that an oxidizing gas such as oxygen, air, and moisture can be used to form a reactive plasma without generating impurities.

The present invention is characterized in that to form a reactive plasma using a microwave plasma having the above advantages, further optimized by the type of mixed gas and the temperature of the reactive plasma to form a reactive plasma pure anatase-type titania nanoparticles It provides a method of manufacturing.

The method for preparing titania nanoparticles according to the present invention includes the following steps.

(a) preparing a mixed gas comprising oxygen gas and water vapor

The mixed gas becomes a raw material of the reactive plasma. The present invention may include water vapor in addition to oxygen gas in the mixed gas to prevent the titania nanoparticles from becoming amorphous, and have a sphericity of 0.9 or more. As can be seen in the following examples and comparative examples, when the reactive plasma is formed using only oxygen gas without water vapor, spherical titania particles are hardly generated, and irregular titania particles of various shapes and sizes are produced. Can be. Unlike the present invention, when only oxygen gas is used without containing water vapor, rutile phase is generated in the nucleation step, and thus it is difficult to obtain titania in pure anatase phase.

The supply flow rate of the water vapor in the mixed gas may be a chemical equivalent or more capable of oxidizing all of the gaseous titanium tetrachloride supplied to the reactor. When the amount of water vapor supplied is less than the chemical equivalent of oxidizing all of the gaseous titanium tetrachloride, titania nanoparticles having a small non-uniform shape, size and specific surface area and high rutileization rate may be produced. The chemical equivalent capable of oxidizing all of the gaseous titanium tetrachloride means a chemical equivalent of water vapor when the gaseous titanium tetrachloride is reacted with only water vapor, and may be, for example, 2 moles of water vapor with respect to 1 mole of titanium tetrachloride. . Preferably the water vapor may be at least one, preferably at least ten times the volume of titanium tetrachloride in the gas phase when the feed gas is brought to standard conditions.

Furthermore, the supply flow rate of the oxygen gas in the mixed gas may be a chemical equivalent or more capable of oxidizing all of the gaseous titanium tetrachloride supplied to the reactor. The chemical equivalent capable of oxidizing all of the gaseous titanium tetrachloride means a chemical equivalent of oxygen gas when the gaseous titanium tetrachloride is reacted with only oxygen gas, for example, 1 mole of oxygen per 1 mole of titanium tetrachloride. Can be. Preferably the oxygen gas may be at least one, preferably at least ten times the volume of titanium tetrachloride in the gas phase when the feed gas is brought to a standard state.

Based on the results, the volume ratio of oxygen gas and water vapor in the mixed gas may be 1: 1 to 10: 1. When the volume ratio of oxygen gas and water vapor in the mixed gas is within the above range, the titania nanoparticles to be produced may be formed into a spherical shape, and further, anatase type of high purity.

When the volume ratio of oxygen gas and water vapor is 1: 1, when the volume ratio of water vapor exceeds this, the microwave plasma may be heated up, thereby failing to generate a reactive plasma at a target temperature. In addition, under a 10: 1 volume ratio of oxygen gas and water vapor, when the volume ratio of water vapor is lower than this, sufficient anatase-type titania may not be formed.

(b) microwave plasma  By using a generator, the mixed gas was reacted at 1,400 ° C. to 1,500 ° C. With plasma  Forming steps

The mixed gas may be supplied to the reactor as a reactive plasma of 1,400 ° C. to 1,500 ° C. through a microwave plasma generator provided at the mixed gas inlet (or inlet). Specifically, the reactive plasma may be formed by directly injecting the mixed gas into the plasma generated by the microwave plasma generator.

When the temperature of the reactive plasma is within the above range, it can be confirmed through the Examples and Comparative Examples that spherical pure anatase-type titania nanoparticles are formed. Specifically, when the temperature of the reactive plasma is less than the above range, rutile titania nanoparticles may be formed together. In addition, when the temperature of the reactive plasma is greater than the above range, aggregation between particles, non-uniformity of components due to partial crystallization, faceting due to grain growth, grain surface roughness, and the like may occur.

(c) within the reactor, Titanium Tetrachloride (TiCl ₄ )of  The reactivity With plasma  Contact Titania  Forming steps

The gaseous titanium tetrachloride may be formed by heating liquid titanium tetrachloride to 400 ° C. or higher. Specifically, the gaseous titanium tetrachloride may be obtained by vaporizing liquid titanium tetrachloride at 400 ° C to 900 ° C, more preferably at 400 ° C to 700 ° C, and even more preferably at 400 ° C to 500 ° C. .

The gaseous titanium tetrachloride is supplied to the reactor through the gaseous titanium tetrachloride inlet (or inlet), and in contact with the reactive plasma to form gaseous titania. The gaseous titanium tetrachloride may be supplied mixed with the transport gas. In this case, the transport gas may be oxygen, nitrogen, argon or air. The amount of supply gas (supply flow rate) may be 5 L / min to 20 L / min, if less than 5 L / min of titanium tetrachloride can reduce the production efficiency, lower than 20 L / min, reactive if more than 20 L / min It may lower the temperature of the plasma.

Within the reactor, the gaseous titanium tetrachloride (TiCl ₄ ) and carrier gas mixture can be injected with an injection angle of about 5 ° to 30 ° from the reactor inner wall for effective contact (mixing) with the reactive plasma. When the injection angle is less than 5 °, the titanium tetrachloride (TiCl ₄ ) and the carrier gas mixture can escape through the reactor inner wall without contacting the plasma flame, and when the injection angle is greater than 30 °, it causes severe vortex of the plasma flame and evens out the reactor. The temperature distribution may not be obtained.

The temperature in the reactor may be 1,200 ℃ to 1,500 ℃. When the temperature in the reactor is less than 1,200 ° C, the difference between the plasma temperature and the generated titania may accumulate on the wall of the reactor, and when the temperature in the reactor is higher than 1,500 ° C, thermal damage to the insulation and finishing materials constituting the reactor may be caused. The disadvantage can be generated, which requires the provision of excessive cooling lines for sufficient cooling.

The supply flow rate of oxygen in the mixed gas may be controlled to 1 to 10 equivalents of the supply flow rate of the gaseous titanium tetrachloride.

When the oxygen supply amount in the gas mixture is less than 1 equivalent to the titanium tetrachloride supply in the gas phase, the oxidation of the titanium tetrachloride in the gas phase may not be sufficiently performed. When the amount is more than 10 equivalents, rutile titania having a very small particle size is produced. Can be. That is, when adjusting the oxygen supply amount in the mixed gas within the above range, it is possible to synthesize spherical pure anatase-type titania particles.

(d) of said weather Titania  Cooling down, Titania  Forming nanoparticles

Titania in the gas phase produced through step (c) is passed through a reactor and cooled to form titania nanoparticles. Specifically, step (d) may be to cool the gaseous titania through a cooling line equipped with a cyclone trap at the end.

The temperature of the cooling line is 15 ℃ to 25 ℃, the flow rate of the titania in the gas phase passing through the cooling line may be 25 L / min to 50 L / min.

The cooling line may be configured in the form of a double tube so that the inside is connected to the reactor and the outside is configured to flow the cooling water cooled by the chiller. At this time, the temperature of the cooling water may be 15 ℃ to 25 ℃.

The cooling line may be configured such that titania generated from the reactor is directly mixed with water or gas and cooled. At this time, the water may be sprayed to the tube connected to the reactor in the form of a spray, the cooling gas may be one of nitrogen, argon, oxygen, chlorine gas or a mixture thereof. At this time, the amount of water injected into the cooling line may be 0.1 L / min to 50 L / min. In addition, the amount of cooling gas injected into the cooling line may be 10 L / min to 500 L / min.

Specifically, the flow rate of the titania in the gas phase passing through the cooling line may be 25 L / min to 50 L / min, the amount of water injected into the cooling line is 0.1 L / min to 50 L / min, The amount of cooling gas injected into the cooling line may be 10 L / min to 500 L / min.

The cooling line may consist of stainless steel coated with ceramic or Teflon to prevent damage from the reaction byproduct hydrochloric acid.

The cyclone collecting unit may be a cyclone device configured to flow the cooling water cooled outside by the chiller. At this time, the temperature of the cooling water may be 15 ℃ to 25 ℃. Therefore, the cyclone collector can perform both roles of cooling and collecting the reactants and by-products at the same time.

The cyclone collecting unit may be a bag filter device composed of a hepa filter. The cyclone collecting unit may include a plurality of cyclone apparatuses and a bag filter apparatus.

The cyclone collector may be made of stainless steel coated with ceramic or Teflon to prevent damage from hydrochloric acid, the inner tube of which is a byproduct of reaction.

Furthermore, the nanoparticle collecting part may be connected to the end of the cyclone collecting part. The nanoparticle collecting part may be provided to be easily separated from the cyclone collecting part, and the size and material thereof are not limited and may be appropriately adjusted as necessary.

The titania nanoparticles may be pure anatase titania nanoparticles having a sphericity of 0.9 or more.

The sphericity can be evaluated by the following equation by image analysis of SEM images.

[expression]

Sphericality = 4πL1 / (L2) ²

(Wherein L1 represents the projection area of the particle and L2 represents the projection contour length of the particle.)

In addition, the purity of the anatase type of titania nanoparticles obtained through step (d) may be 90% or more, 95% or more, specifically 100%. More specifically, the pure anatase-type titania nanoparticles may be 90% or more, 95% or more, specifically 100%, of the anatase type of titania nanoparticles prepared.

The purity of the anatase formulation can be confirmed by XRD analysis. Specifically, as a result of XRD analysis, when only the peak of the anatase crystal surface 101 appears at 25.3 ° and the peak of the rutile (rutile) crystal surface 110 appears at 27.5 ° does not exist, pure anatase It can be judged that the type titania nanoparticles have been obtained. When the anatase and rutile types are mixed, the area ratio (I _A and I _R ) of the anatase and rutile (rutile) peaks mentioned above on the XRD is substituted into the following formula for purity of the anatase type [A] Can be calculated.

1 is a schematic diagram of a device for implementing a method of manufacturing titania nanoparticles according to an embodiment of the present invention. In detail, the mixed gas flows into the reactor 4 through the mixed gas inlet 2, and is supplied to the reactor by the reactive plasma through the microwave plasma generator 1, and the titanium tetrachloride inlet 3 of the gas phase is provided. The gaseous carbon tetrachloride supplied through the reaction reacts with the reactive plasma to form gaseous titania. The resulting gaseous titania travels along the cooling line 5 to the cyclone collector 6 and is cooled, whereby titania nanoparticles can be obtained from the nanoparticle collector 7.

Titania nanoparticles prepared as described above are titania nanoparticles with a uniform spherical shape and high purity of anatase type, color printing toner, sunscreen, harmless high-grade electronic paper, laminated ceramic capacitor (MLCC), lithium secondary Applicable to industrial materials such as batteries.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention is not interpreted to be limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present invention to those skilled in the art.

Microwave plasma apparatuses used in Examples 1 and 2 and Comparative Examples 1 to 4 were manufactured and supplied by Green Science Co., Ltd. in Korea. Specifically, the microwave plasma apparatus includes a power supply; A magnetron system consisting of a magnetron generating 2.45 GHz electromagnetic waves and an isolator which prevents reflected waves reflected from the magnetron; A 3-stub tuner for controlling the magnitude of the incident wave and the reflected wave; It consists of a quartz tube in which plasma is generated by electromagnetic waves and a reactive gas injected from the outside.

The reactors used in Examples 1 and 2 and Comparative Examples 1 to 4 had an inner diameter of 60 mm and a length of 1,300 mm, the inside of which was made of a heat-resistant ceramic material of 200 mm thickness and the outside of stainless steel metal. Plasma generation conditions were controlled at an output power of 1.0 kW to 3.5 kW at a frequency of 2.45 GHz and the temperature conditions were varied. The gaseous titanium tetrachloride was supplied mixed with an argon transfer gas, and the amount of the transfer gas was 10 L / min, and was injected with an injection angle of 10 ° from the reactor inner wall.

Oxygen was injected at a rate of 20 L / min into the reaction gas injected into the plasma in Comparative Examples 3 and 4, and in Example 1, Comparative Example 1 and Comparative Example 2, oxygen was injected at a rate of 20 L / min. Water vapor was added so that the volume ratio of gas to water vapor was 5: 1. In Comparative Example 5, a flame burner having a diameter of 50 mm and a length of 200 mm was used, and the burner was fed at 1 L / min of methane and 3 L / min of oxygen flow rate.

The conditions of the preparation method of titania nanoparticles according to Examples 1 to 2 and Comparative Examples 1 to 5 are shown in Table 1 below.

Mixed gas (or reactive gas) injected into the plasma Plasma temperature TiCl Production Example 1 Oxygen + moisture 1,450 ℃ 5 g / min Example 2 Oxygen + moisture 1,450 ℃ 10 g / min Comparative Example 1 Oxygen + moisture 1,200 ℃ 5 g / min Comparative Example 2 Oxygen + moisture 1,200 ℃ 10 g / min Comparative Example 3 Oxygen 1,450 ℃ 9 g / min Comparative Example 4 Oxygen 1,450 ℃ 27 g / min Comparative Example 5 Oxygen + Methane (Flame) 1,000 ℃ ~ 1,500 ℃ 5 g / min

Figure 2 shows the XRD (X-Ray Diffraction) analysis results of titania nanoparticles prepared according to Examples 1, 2 and Comparative Examples 1, 2.

FIG. 3 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Example 1. FIG.

FIG. 4 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Example 2. FIG.

FIG. 5 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 1. FIG.

FIG. 6 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 2. FIG.

FIG. 7 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 3. FIG.

FIG. 8 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 4. FIG.

FIG. 9 shows a scanning electron microscope (SEM) image of titania nanoparticles prepared according to Comparative Example 5. FIG.

10 shows the results of XRD (X-Ray Diffraction) analysis of titania nanoparticles prepared according to Comparative Examples 3 to 5. FIG.

According to FIGS. 2 to 4, titania nanoparticles prepared according to Examples 1 and 2 are completely spherical, and further, rutile titania is not detected and pure anatase-type titania is produced.

On the contrary, according to FIGS. 5 to 10, the titania nanoparticles prepared according to Comparative Examples 1 to 5 are not spherical but irregular, and anatase-type and rutile-type titania are mixed. .

1: microwave plasma generator
2: mixed gas inlet
3: titanium tetrachloride inlet in the gas phase
4: reactor
5: cooling line
6: cyclone collector
7: Nanoparticle Collection

Claims (7)

(a) preparing a mixed gas comprising oxygen gas and water vapor;
(b) forming the mixed gas into a reactive plasma at 1,400 ° C. to 1,500 ° C. using a microwave plasma generator;
(c) in the reactor, contacting gaseous titanium tetrachloride (TiCl ₄ ) with the reactive plasma to form gaseous titania; And
(d) cooling the gaseous titania to form titania nanoparticles;
The titania nanoparticles are pure anatase-type titania nanoparticles having a sphericity of 0.9 or more, the manufacturing method of titania nanoparticles. The method according to claim 1,
The vapor phase titanium tetrachloride is formed by heating the liquid titanium tetrachloride to 400 ℃ or more, the method for producing titania nanoparticles. The method according to claim 1,
The temperature in the reactor is characterized in that 1,200 ℃ to 1,500 ℃, the production method of titania nanoparticles. The method according to claim 1,
Step (d) is characterized in that for cooling the titania in the gas phase through a cooling line equipped with a cyclone trap, the titania nanoparticles manufacturing method. The method according to claim 4,
The temperature of the cooling line is 15 ℃ to 25 ℃, the flow rate of titania in the gas phase passing through the cooling line is characterized in that 25 L / min to 50 L / min, Titania nanoparticles manufacturing method. The method according to claim 1,
The volume ratio of oxygen gas and water vapor in the mixed gas is 1: 1 to 10: 1, characterized in that the manufacturing method of titania nanoparticles. The method according to claim 1,
The supply flow rate of oxygen in the mixed gas is controlled to 1 equivalent to 10 equivalents of the supply flow rate of the gaseous titanium tetrachloride, the method for producing titania nanoparticles.

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