KR101741591B1 - Method and apparatus for manufacturing titania - Google Patents

Abstract

The present invention relates to a method and an apparatus for producing titania. The method comprises the steps of: i) reacting ilmenite (FeTiO_3) with ammonia gas (NH_3) and hydrogen fluoride gas (HF) in an inert atmosphere to cause it to decompose into a titanium compound ((NH_3)_3TiF_7) and an iron compound ((NH_3)_3FeF_6); ii) subjecting the titanium compound to a first thermal treatment to produce a titanium fluoride (TiF_4); iii) subjecting the titanium fluoride to a second thermal treatment with ammonia water (NH_4OH) in an oxidizing atmosphere to produce titania (TiO_2); and iv) sintering the titania to prepare anatase-type titania or rutile-type titania, wherein the NH_3 and HF gases generated in the steps ii) and iii) are collected and recirculated to the step i).

Description

[0001] METHOD AND APPARATUS FOR MANUFACTURING TITANIA [0002]

The present invention relates to a method and an apparatus for producing titania which are excellent in process efficiency and productivity and environmentally friendly.

Titania (TiO ₂ ) is a molecule in which oxygen atoms are bonded to one titanium atom, which is a transition metal, and has a molecular weight of 79.866 g / mol. Titania is physically and chemically stable and has a refractive index of 2.5 or more and is larger than a diamond having the highest refractive index among natural materials. When the refractive index is large, the amount of light emitted from the medium having a low refractive index in the optical material increases. In the optical waveguide type, the size of the optical waveguide core or the thickness of the optical lens can be reduced. Also, dispersing the high refractive index particles in the polymer medium increases the whiteness because of its ability to scatter light. Titania is one of the important industrial materials used as white pigment for a long time due to its high refractive index.

Titania has three crystal forms: anatase, brookite, and rutile. In order to be used as a white pigment, anatase type and rutile type are mainly used because the refractive index should be excellent. The anatase and rutile forms are based on octahedra (TiO ₆ ^{2 -} ) units surrounded by six oxygen ions (O ^2- ) around the titanium ion (Ti ^{4 +} ) in the crystal structure. However, the rutile type is a fine twisted orthotropic system, but the anatase type is a structure in which the octahedron is very distorted and has a much lower symmetry than the orthotropic system. In rutile structure, the crystal units are in line contact while the anatase type is connected in point contact between crystal units. It is known that the rutile type has the largest refractive index and excellent hiding power and tinting power required as a white pigment due to such a structural difference.

Methods for industrially producing titania include a chlorine method, a sulfuric acid method, and a sol-gel method using an alkoxide.

The sulfuric acid method produces titanium sulfate (TiOSO ₄ ) by pulverizing titanium oxide and reacting with concentrated sulfuric acid. (TiO (OH) ₂ ) is obtained by hydrolyzing the titanium sulfate to obtain titania of the desired size after growing the anatase type titania by calcining it at 800 to 1000 DEG C, and further adding anatase type titania to the 1,100 Lt; 0 > C or more to produce rutile type titania.

Although this method is advantageous in mass production, the use of a high concentration of sulfuric acid consumes a large amount of water in the water washing process, and waste such as iron sulfate is generated, thereby causing a great deal of environmental processing cost. In addition, since a high-temperature heat treatment and a severe grinding process are required, there is a problem that the quality of the final product is greatly deteriorated due to relatively high equipment cost and a large amount of impurities.

The chlorine method is a process in which titanium chloride tetrachloride (TiCl ₄ ) gas having a low purity is obtained by reacting natural rutile and synthetic rutile having high titania purity of 90% or more with chlorine gas at a high temperature, It is a method of forming titania particles in oxygen and high temperature vapor phase. This chlorine method can obtain rutile titania with a comparatively high purity. However, since anatase titania can not be produced, corrosive gas (HCl, Cl ₂ ) which is dangerous during the reaction is generated, There is a problem that the production cost is high.

In the sol-gel method, a titanium alkoxide such as titanium tetraisopropoxide or titanium tetrabutoxide is added to a solvent such as alcohol or water, and the titania sol ) And then heat treatment. This method has a relatively small particle size and can be obtained at a high purity and is advantageous for thin film coating, but has a drawback that the cost of the product is very high because it uses an expensive raw material.

Conventional methods of producing titania are dangerous for handling materials and processes, as well as complicated processes, high production costs, low yield and productivity problems, and have a large environmental load. Various techniques for improving the titania production method have been proposed.

For example, Korean Patent No. 10-1565477 discloses a technique for controlling the size of titanium dioxide nanoparticles by performing a pressurization step before or after a hydrolysis step in a method for producing a titanium oxide derivative using a sulfuric acid method.

Korean Patent Laid-Open Publication No. 2015-0072264 discloses a technology for improving the dispersibility and transparency of titanium oxide nanoparticles by performing a hydrothermal synthesis reaction and a water-based synthesis reaction under specific high-temperature and high-pressure conditions in the production of titania sol .

Korean Patent Laid-Open Publication No. 2015-0076898 discloses a technique for continuously producing titania through reaction of titanium oxide with a fluorine compound, but since a dry process and a wet process are mixed, application to a commercialization facility as a continuous process it's difficult. In addition, use of fluorinated compounds in a solid state may reduce the efficiency, prolong the manufacturing time, and may cause environmental pollution since all byproducts generated in each step of the process are discarded.

These patents have improved some of the problems of the existing titania manufacturing method to some extent, but the effect is not sufficient. Therefore, there is a need for research on a manufacturing method and apparatus for producing titania having high yield and quality characteristics through an environmentally friendly and simple process.

Korean Patent No. 10-1565477 (Oct. 27, 2015), a method for producing a titanium oxide derivative Korean Patent Laid-Open Publication No. 2015-0072264 (June 29, 2015), a method for producing high-refractive-index titania sol having excellent dispersibility Korean Patent Laid-Open Publication No. 2015-0076898 (Jul. 2015.07.07), a method for producing TiO2 using a fluorinated compound

As a result of various studies to solve the above problems, the present inventors have found that, when ammonia and hydrogen fluoride in gaseous state are utilized and a continuous process is introduced, and ammonia and hydrogen fluoride generated in respective stages are reused, It was confirmed that not only the yield and quality can be improved but also the generation of waste can be minimized.

Accordingly, an object of the present invention is to provide a process for producing titania which is excellent in process efficiency and environmentally friendly.

Another object of the present invention is to provide an apparatus for producing titania using the above production method.

In order to achieve the above object,

(NH ₃ ) ₃ TiF ₇ ) and an iron compound ((NH ₃ ) ₃ FeF ₆ ) by reacting titanium oxide (FeTiO ₃ ) with ammonia (NH ₃ ) gas and hydrogen fluoride (HF) gas under an inert atmosphere, ;

Ii) subjecting the titanium compound to a first heat treatment to produce titanium fluoride (TiF ₄ );

Iii) subjecting the titanium fluoride to a second heat treatment together with ammonia water (NH ₄ OH) under an oxidizing atmosphere to produce titania (TiO ₂ ); And

(Iv) baking the titania to produce anatase-type titania or rutile-type titania, the method comprising the steps of:

And recovering the ammonia gas and the hydrogen fluoride gas produced in the steps ii) and iii) and recirculating the ammonia gas and the hydrogen fluoride gas to the step i).

The step i) is carried out at a temperature of 100 to 200 ° C.

Wherein the ammonia gas and the hydrogen fluoride gas are used in the step i) in an amount of 10 to 15 moles, respectively, relative to 1 mole of the titanate.

Wherein ammonia gas and water are recovered from step i) and supplied to step iii).

And the first heat treatment of step ii) is performed at a temperature of 250 to 400 ° C.

At this time, the iron compound ((NH ₃ ) ₃ FeF ₆ ) produced in the step i) is removed through the first heat treatment.

The second heat treatment of iii) is performed by injecting air or oxygen at a temperature of 450 to 750 ° C.

Wherein the anatase-type titania is produced when the firing temperature of step iv) is lower than 550 to 950 占 폚, and rutile-type titania is produced when the firing temperature is 950 to 1200 占 폚.

Further, in order to selectively produce anatase-type titania or rutile-type titania,

A first reactor for reacting titanium oxide, ammonia gas and hydrogen fluoride gas under an inert atmosphere to produce a titanium compound and an iron compound;

A second reactor that is connected to the first reactor by piping to generate titanium fluoride by first heat treating the titanium compound introduced therefrom;

A third reactor connected to the second reactor and connected to the third reactor for generating titania by performing a second heat treatment on the titanium fluoride introduced therefrom together with ammonia water under an oxidizing atmosphere;

A fourth reactor for producing anatase-type titania or rutile-type titania by firing titania introduced thereinto from a pipeline connected to the third reactor; And

And a recovering unit for collecting the anatase-type titania or the rutile-type titania that is piped to the fourth reactor and introduced thereinto, the apparatus comprising:

And a return line for collecting ammonia gas and hydrogen fluoride gas generated in the second reactor and the third reactor and supplying the collected ammonia gas and hydrogen fluoride gas to the first reaction section.

Wherein the apparatus for producing titania further comprises a return line for recovering ammonia gas and water from the first reactor and supplying the recovered ammonia gas and water to the third reactor.

The apparatus for producing titania may further include a chamber for discharging the iron compound subjected to the first heat treatment in the second reactor to the outside.

The apparatus for producing titania may further include a supply line for supplying air or oxygen to the third reactor.

The method and apparatus for producing titania according to the present invention have the following advantages.

(1) Reaction activity can be further enhanced by reacting titanium oxide with gaseous ammonia and hydrogen fluoride. In addition, the ammonia gas and the hydrogen fluoride gas generated at each stage can be recovered and reused without a separate processing step, thereby reducing the cost and minimizing the waste discharge, thereby being environmentally friendly.

(2) By introducing a continuous process, it is possible not only to improve the properties of the finally obtained titania, but also to ensure the uniformity of the quality, and to increase the process efficiency and mass production.

(2) Both the anatase type and the rutile type titania can be easily produced by controlling the firing temperature.

FIG. 1 is a process flow diagram illustrating a method for producing titania according to an embodiment of the present invention.
2 is a view schematically showing an apparatus for producing titania according to an embodiment of the present invention.
3 and 4 are SEM (scanning electron microscope) photographs and X-ray diffraction spectroscopy (XRD) pattern photographs of rutile titania according to Example 1 of the present invention.
5 and 6 are SEM (scanning electron microscope) photographs and X-ray diffraction spectroscopy (XRD) pattern photographs of anatase type titania according to Example 4 of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and is not limited to the embodiments and examples described herein. In the drawings, like reference numerals refer to like elements, and for convenience of description, components shown in the drawings may be simplified, exaggerated, or omitted as long as they do not affect the rights of the present invention.

As used herein, the terms " titania " to " titanium oxide " refer to oxidized titanium and its crystals stoichiometrically represented as TiO ₂ , which represent substantially the same material. However, in order to avoid confusion of the objects to be referred to in the present specification, the terms of the two are used differently, and they do not mean completely different materials.

TECHNICAL FIELD The present invention relates to a manufacturing method and a manufacturing apparatus for manufacturing an efficient and environmentally friendly titania through a continuous process.

Conventional titania production methods such as the sulfuric acid method, the hydrochloric acid method and the sol-gel method have drawbacks in terms of process efficiency, safety, economical efficiency and productivity, as well as a large amount of waste, which has a great impact on the environment.

Therefore, instead of using a starting material having a high risk of sulfuric acid, hydrochloric acid, or the like or a starting material having a high raw material cost, anatase type or rutile type titania can be selectively produced by decomposing the titanium oxide using gaseous ammonia and hydrogen fluoride And a manufacturing method and a manufacturing apparatus of the titania.

In addition, since the method and apparatus for producing titania according to the present invention are continuous processes, simplification and efficiency of the process can be achieved, and the by-products produced inevitably in each reaction step are recovered and used again for the reaction. And can reduce production costs.

First, a method of manufacturing titania according to one embodiment of the present invention will be described in detail.

FIG. 1 is a process flow diagram illustrating a method for producing titania according to an embodiment of the present invention.

As shown in FIG. 1, the method for producing titania according to the present invention comprises

(NH ₃ ) ₃ TiF ₇ ) and an iron compound ((NH ₃ ) ₃ FeF ₆ ) by reacting titanium oxide (FeTiO ₃ ) with ammonia (NH ₃ ) gas and hydrogen fluoride (HF) gas under an inert atmosphere, ;

Ii) subjecting the titanium compound to a first heat treatment to produce titanium fluoride (TiF ₄ );

Iii) subjecting the titanium fluoride to a second heat treatment together with ammonia water (NH ₄ OH) under an oxidizing atmosphere to produce titania (TiO ₂ ); And

Iv) firing the titania to produce anatase-type titania or rutile-type titania.

The steps i) to iv) are continuous, and the ammonia gas and the hydrogen fluoride gas produced in steps ii) and iii) may be recovered and recycled to step i).

Each step will be described as follows.

First, step (i) is a step of decomposing titanium oxide (FeTiO ₃ ) into a titanium compound ((NH ₃ ) ₃ TiF ₇ ) and an iron compound ((NH ₃ ) ₃ FeF ₆ ). Specifically, the step (i) above decomposes the titanium oxide into an iron compound and a titanium compound by reacting it with an ammonia (NH ₃ ) gas and a hydrogen fluoride (HF) gas under an inert atmosphere.

(Scheme 1)

_{FeTiO 3 (s) + 13NH 3} (g) + 13HF (g) → (NH 3) 3 TiF 7 (s) + (NH 3) 3 FeF 6 (s) + 3H 2 O (l) + 7NH 3 (g )

Particularly, since ammonia and hydrogen fluoride reacting with the titanate are supplied in a gaseous state in the step i), the ammonia gas and the hydrogen fluoride gas generated in steps ii) and iii) And can be reused without being processed. Accordingly, the method of manufacturing titania according to the present invention is eco-friendly since the waste generated during the manufacturing process is minimized, and the production cost can be greatly reduced.

The step i) is carried out in an inert atmosphere, and it is sufficient that the inert atmosphere is oxygen-free using an inert gas such as nitrogen or argon.

In the step i), the ammonia gas and the hydrogen fluoride gas may be supplied in an amount of 10 to 15 mol, preferably 11 to 14 mol, relative to 1 mol of the titanium oxide. When the ammonia gas and the hydrogen fluoride gas are injected in the molar ratio range, the titanium compound (NH ₃ ) ₃ TiF ₇ , which is an intermediate product, can be produced by mixing well with the titanium oxide and proceeding a sufficient decomposition reaction. In order to maintain the molar ratio, the ammonia gas and the hydrogen fluoride gas may be supplied at a constant flow rate and may be injected at 10 to 100 mL / min, although not particularly limited thereto.

The step i) may be carried out at a temperature of 100 to 200 ° C, preferably 150 to 200 ° C. If the temperature is less than the above range, the reaction can not proceed sufficiently. On the other hand, if the temperature is higher than the above range, the reaction may excessively proceed to deteriorate the characteristics of the intermediate product or adversely affect subsequent steps. There may arise a problem of increasing.

The reaction time in the above step i) is not particularly limited and can be maintained within the above-mentioned temperature range for 3 to 6 hours, preferably 4 to 6 hours, though it depends on the actual heating temperature.

Further, as described in Scheme 1, the ammonia gas and water from the step i) can be recovered and supplied to the step iii) and reused, and the iron compound ((NH ₃ ) ₃ FeF ₆ ) (FeFe ₃ ) through the first heat treatment of the iron (FeFe).

Next, step ii) is a step of producing titanium fluoride (TiF ₄ ) by first heat-treating the titanium compound ((NH ₃ ) ₃ TiF ₇ ) produced in the step i). The first heat treatment reaction is a step of removing impurities present in the titanium compound obtained in the previous step and pyrolyzing the titanium compound as follows.

(Scheme 2)

(NH ₃ ) ₃ TiF ₇ (s)? TiF ₄ (s) + 3HF (g) + 3NH ₃ (g)

The first heat treatment of step ii) may be performed at a temperature of 250 to 400 ° C, preferably 300 to 400 ° C. If the temperature of the first heat treatment is less than the above range, the reaction for producing titanium fluoride does not occur. On the other hand, if the temperature exceeds the above range, the reaction proceeds excessively and physical properties of titanyl fluoride are changed.

The primary heat treatment time in the step (ii) is not particularly limited and can be maintained within the above-mentioned temperature range for 1 to 4 hours, preferably 1 to 2 hours, though it differs depending on the actual heating temperature.

The ammonia gas and hydrogen fluoride gas produced in step ii) can be recovered and reused in step i).

In addition, the iron compound ((NH ₃ ) ₃ FeF ₆ ) in the by-product produced in the above-mentioned step i) during the first heat treatment in the step (ii) is also heat-treated at this time.

(Scheme 3)

_{(NH 3) 3 FeF 6 (} s) → FeF 3 (s) + 3HF (g) + 3NH 3 (g)

The iron compound is transformed into iron fluoride (FeFe ₃ ) by the reaction of the reaction formula ( ₃ ), which can be removed in the form of iron oxide through an additional oxidation process. In addition, the ammonia gas and hydrogen fluoride gas produced during the heat treatment of the iron compound can be recovered and reused in step i).

Next, iii) is a step of generating titania (TiO ₂ ) by performing _second heat treatment of the titanium fluoride (TiF ₄ ) produced in step ii) together with ammonia water (NH ₄ OH) under an oxidizing atmosphere. The second heat treatment is a step of sublimating titanium fluoride.

(Scheme 4)

_{TiF 4 (s) + 2NH 4} OH (l) + O 2 (g) → TiO 2 (s) + 2NH 3 (g) + 4HF (g) + 2H 2 O

The second heat treatment of step iii) may be performed at a temperature of 450 to 750 ° C, preferably 550 to 750 ° C. If the temperature of the second heat treatment is less than the above range, the formation of titania is insufficient. On the other hand, if the temperature exceeds the above range, the quality of the finally obtained titania may be deteriorated due to excessive reaction.

In addition, the secondary heat treatment time in the step iii) is not particularly limited and can be maintained within the above-mentioned temperature range for 3 to 6 hours, preferably 3 to 5 hours, depending on the actual heating temperature.

In addition, the secondary heat treatment may be performed in an oxidizing atmosphere, and air or oxygen may be injected for this purpose. At this time, the concentration of oxygen is not particularly limited, and the amount of oxygen supplied can be controlled according to the reaction conditions.

Also, the ammonia and hydrogen fluoride produced in step iii) may be recovered and reused in step i).

Next, the step iv) is a step of producing anatase type titania or rutile type titania by firing the titania obtained in the step iii).

At this time, the crystalline phase of titania can be controlled according to the firing temperature of step iv). Specifically, when the firing temperature of step iv) is less than 550 to 950 ° C, anatase type titania can be produced, and when the firing temperature is 950 to 1200 ° C, rutile type titania can be produced. Particularly, When the calcination temperature of iv) is 700 to 900 ° C, the crystal phase is converted to 100% by anatase type titania. When the calcination temperature is 1000 to 1200 ° C, the crystal phase can be converted to 100% by rutile type titania.

The baking time of the step iv) is not particularly limited, and may vary depending on the actual heating temperature. However, the baking time in the step iv) can be generally maintained within the above-mentioned temperature range for preferably 1 to 2 hours.

The anatase-type titania or rutile-type titania produced in the step iv) may be subjected to additional cooling and collecting processes for recovery. Since the temperature of the titania is high, a process of cooling the titania and a collecting process of collecting and recovering the cooled titania may be performed. At this time, a rapid cooler may be used for the cooling process, and a particle collector may be used for the collecting process.

The particle size of the titania obtained through the above-described production method may be tens or hundreds of nanometers, and further processing such as milling may be performed depending on the intended use.

Next, an apparatus for producing titania according to one embodiment of the present invention will be described in detail.

2 is a view schematically showing an apparatus for producing titania according to an embodiment of the present invention.

Referring to FIG. 2, an apparatus 100 for producing titania according to an embodiment of the present invention includes a first reactor 10 for producing titanium compounds and iron compounds by reacting titanium oxide, ammonia gas, and hydrogen fluoride gas in an inert atmosphere, ;

A second reactor (20) connected to the first reactor (10) to generate titanium fluoride by performing a first heat treatment on the titanium compound introduced from the first reactor (10);

A third reactor (30) connected to the second reactor (20) to generate titania by subjecting the titanium fluoride introduced therefrom to a second heat treatment together with ammonia water under an oxidizing atmosphere;

A fourth reactor 40 connected to the third reactor 30 for producing anatase-type titania or rutile-type titania by burning the titania introduced therefrom; And

And a collector 50 for collecting the anatase-type titania or the rutile-type titania that is piped to the fourth reactor 50 and introduced thereinto.

The first reactor 10 includes a space for mixing and reacting the externally introduced titanium oxide with the ammonia gas and the hydrogen fluoride gas B and is capable of reacting with the titanium (A) and the ammonia Each inlet for injecting gas and hydrogen fluoride gas, and an outlet for transferring the product through the decomposition reaction to the second reactor 20, which is the next process.

Particularly, the first reactor 10 of the apparatus for producing titania according to the present invention is capable of supplying the ammonia gas and the hydrogen fluoride gas collected from the second reactor 20 and the third reactor 30, As shown in FIG. In addition, the ammonia gas and the water are recovered from the reaction in the first reactor 10 and further have a separate outlet and a return line 12 for supplying the recovered ammonia gas and water to the third reactor 30.

The first reactor 10 may be a rotary reactor equipped with a heating device to increase the degree of mixing and reactivity of reactants contained therein. At this time, the heating apparatus and the reactor for rotating are not particularly limited as they are commonly used in the art.

The amounts of the titanium oxide (A), the ammonia gas and the hydrogen fluoride gas (B) injected into the first reactor 10 and the temperature of the first reactor 10 are as described above.

The second reactor 20 includes a space for accommodating the titanium compound and the iron compound introduced from the first reactor 10 and a heating device for the first heat treatment, An inlet for injecting the reaction product of the first reactor 10 and an outlet for transferring the generated titanium fluoride to the third reactor 30.

At this time, the second reactor 20 includes a separate outlet and return line 22 for collecting the ammonia gas and the hydrogen fluoride gas generated from the first heat treatment reaction and returning the ammonia gas and the hydrogen fluoride gas to the first reactor.

In addition, the second reactor 20 includes an additional outlet and a chamber 60 for removing the first heat treated iron compound.

In the second reactor 20, a rotary reactor equipped with a heating device may be used to enhance the reaction activity. At this time, the heating apparatus and the reactor for rotating are not particularly limited as they are commonly used in the art.

The temperature of the second reactor 20 is as mentioned above.

The third reactor (30) includes a space for receiving the titanium fluoride introduced from the second reactor (20) and a heating device for the second heat treatment, and the third reactor (30) An inlet for injecting titanium fluoride in the second reactor 20, an outlet for transferring the titania produced in the other side to the fourth reactor 40, and an oxygen or air supply line 34 for forming an oxidizing atmosphere.

At this time, the third reactor 30 includes a separate discharge port and a return line 32 for collecting the ammonia gas and the hydrogen fluoride gas generated from the second heat treatment reaction and returning the ammonia gas and the hydrogen fluoride gas to the first reactor.

In the third reactor 30, a rotary reactor equipped with a heating device may be used to enhance the reaction activity. At this time, the heating apparatus and the reactor for rotating are not particularly limited as they are commonly used in the art.

The temperature of the third reactor 30 is as mentioned above.

The fourth reactor 40 includes a space for accommodating the titania introduced from the third reactor 30 and a firing furnace for firing, and the fourth reactor 40 includes a titania And an outlet for transferring the generated anatase or rutile titania produced on the other side to the recovery unit 50. [

The firing furnace included in the fourth reactor 40 may be a firing furnace commonly used in the art for the high-temperature heat treatment of titania.

At this time, the temperature of the fourth reactor (40) is as mentioned above.

The recovery unit 50 includes an inlet for receiving the anatase-type or rutile-type titania generated from the fourth reactor 40 and a space for accommodating the introduced anatase-type or rutile-type titania.

A grinding unit (not shown) for grinding may be further provided between the fourth reactor 40 and the recovery unit 50 to obtain titania in powder form in the recovery unit 50.

The apparatus and method for manufacturing titania according to the present invention have the following advantages in comparison with the conventional manufacturing process.

First, the reaction activity can be further increased by reacting titanium oxide with gaseous ammonia and hydrogen fluoride. In addition, the ammonia gas and the hydrogen fluoride gas generated at each stage can be recovered and reused without a separate processing step, thereby reducing the cost and minimizing the emission of waste, thereby being eco-friendly.

Second, by introducing a continuous process, it is possible not only to improve the characteristics of the finally obtained titania, but also to ensure the uniformity of the quality, to increase the process efficiency and mass production.

Thirdly, both the anatase type and the rutile type titania can be easily produced by controlling the firing temperature.

Hereinafter, examples and comparative examples of the present invention will be exemplified. The following examples are provided to illustrate the present invention in order to facilitate understanding of the present invention, and thus the technical scope of the present invention is not limited thereto.

Example  And Comparative Example : Titania  Produce

[Example 1]

In order to prevent internal coating, a ball made of carbon is placed in a 30 L rotating electric furnace, and 250 g of ilmenite (1,200 g) and 1,250 g of H ₂ SiF ₆ (l) are added and mixed in an NH ₃ (g) atmosphere at 180 ° C. for 5 hours And heated. The generated titanium compound was automatically transferred to a two - stage section of a 30 L rotary electric furnace by rotation. In this section, impurities were removed through a first heat treatment at 350 ° C. for 1 hour, and titanium fluoride was produced.

Titanium fluoride was then moved to the top of the rotary furnace, and titanium fluoride was subjected to a secondary heat treatment at 650 ° C for 4 hours to produce titania. The obtained titania was transferred to a titania production reactor and reacted at 1100 ° C for 2 hours to produce crystalline titania.

[Example 2]

Crystalline titania was prepared in the same manner as in Example 1, except that the calcination temperature was changed to 1000 ° C in the titania production reactor.

[Example 3]

Crystalline titania was prepared in the same manner as in Example 1, except that the calcination temperature was changed to 1200 ° C in the titania production reactor.

[Example 4]

Crystalline titania was prepared in the same manner as in Example 1 except that the calcination temperature was changed to 900 ° C in the titania production reactor.

[Example 5]

Crystalline titania was prepared in the same manner as in Example 1, except that the calcination temperature was changed to 800 DEG C in the titania production reactor.

[Example 6]

Crystalline titania was prepared in the same manner as in Example 1, except that the calcination temperature was changed to 700 ° C in the titania production reactor.

[Example 7]

Crystalline titania was prepared in the same manner as in Example 1, except that the calcination temperature was changed to 950 ° C in the titania production reactor.

[Example 8]

Crystalline titania was prepared in the same manner as in Example 1 except that the calcination temperature was changed to 925 ° C in the titania production reactor.

[Example 9]

Crystalline titania was prepared in the same manner as in Example 1 except that the temperature during the second heat treatment was changed to 750 ° C.

[Example 10]

Crystalline titania was prepared in the same manner as in Example 1 except that the temperature during the second heat treatment was changed to 550 ° C.

[Example 11]

Crystalline titania was prepared in the same manner as in Example 1, except that the temperature during the first heat treatment was changed to 300 캜.

[Example 12]

Crystalline titania was prepared in the same manner as in Example 1 except that the temperature during the first heat treatment was changed to 250 캜.

[Example 13]

Crystalline titania was prepared in the same manner as in Example 1 except that the temperature during the first heat treatment was changed to 400 ° C.

[Comparative Example 1]

Crystalline titania was prepared in the same manner as in Example 1 except that the calcination temperature was changed to 1300 ° C in the titania production reactor.

[Comparative Example 2]

Crystalline titania was prepared in the same manner as in Example 1 except that the temperature was changed to 500 ° C during the secondary heat treatment.

[Comparative Example 3]

Crystalline titania was prepared in the same manner as in Example 1, except that the temperature during the first heat treatment was changed to 200 ° C.

Experimental Example  1: Depending on firing temperature Titania  Determination of Crystallinity

The particle size, crystal phase and CIE L of titania prepared in Examples 1 to 8 and Comparative Example 1 were measured. The results obtained are shown in Table 1 below.

(1) particle size

For sample analysis, pretreatment of platinum coating was performed using 208HR (Cressington, UK) as a sputter coating equipment, and image analysis was performed using JSM-4101F (JEOL LTD, Japan). The particle size was measured by SEM image.

(2) Conversion rate (%)

The prepared sample was fixed to a holder and analyzed using an X-ray diffraction analyzer D / MAX-2500V (Rigaku, Japan). The collected data were converted to spectrum using software and the diffraction patterns were analyzed. The conversion ratios were measured by calculating the ratios of rutile and anatase types.

(3) CIE L (whiteness degree)

The whiteness of the prepared sample was measured by CIE L using a display color analyzer CA-210 apparatus manufactured by Konica Minolta. CIE L is a unit of degree of white color. The closer to 100, the closer to pure white the color. The closer to 0 the closer the color to black. When the CIE L value is less than 90, it becomes yellowish white, making it difficult to use it as a dye such as a paint.

Particle size
(nm) Conversion rate (%) according to crystal phase CIE L Anatase type Ruta type Example 1 340 0 100 93.6 Example 2 320 0 100 94.1 Example 3 420 0 100 93.2 Example 4 40 100 0 94.3 Example 5 20 100 0 95.2 Example 6 20 100 0 95.0 Example 7 100, 250 40 60 94.1 Example 8 20 80 20 94.8 Comparative Example 1 - - - -

Experimental Example 2: Secondary  Depending on the heat treatment temperature Titania  Property evaluation

The particle size, crystal phase and CIE L of titania prepared in Examples 9 and 10 and Comparative Example 2 were measured. The results obtained are shown in Table 2 below.

Sublimation oil Particle size
(nm) Conversion rate (%) according to crystal phase CIE L Anatase type Ruta type Example 9 U 335 0 100 93.6 Example 10 U 336 0 100 94.1 Comparative Example 2 radish - - - -

Experimental Example 3: Primary  Depending on the heat treatment temperature Titania  Property evaluation

The particle size, crystal phase and CIE L of titania prepared in Examples 11 to 13 and Comparative Example 3 were measured. The results obtained are shown in Table 3 below.

impurities
The presence or absence Particle size
(nm) Conversion rate (%) according to crystal phase CIE L Anatase type Ruta type Example 11 radish 335 0 100 93.6 Example 12 radish 336 0 100 94.1 Example 13 radish 325 0 100 93.5 Comparative Example 3 U 1,000 20 80 92.3

Referring to Tables 1 to 3, according to the present invention, rutile type titania is produced when the firing temperature is 1000 ° C or higher, and anatase type titania is produced when the firing temperature is 700 to 900 ° C. Titania having a constant particle size Can be produced.

Also, when the CIE L value is less than 90, it becomes white with a yellowish color, making it difficult to use it as a dye such as a paint. The CIE L value of the example according to the present invention was measured to be a value of 90 or more, and it was confirmed that the CIE L value could be used as a white pigment.

The method and apparatus for producing titania according to the present invention enable the production of titania efficiently and environmentally friendly through a continuous process.

10: first reactor 20: second reactor
30: third reactor 40: fourth reactor
50: retractor 60: chamber
12, 22, 32: return line 34: oxygen supply line
100: Production apparatus of titania
A: Titanide B: Ammonia gas and hydrogen fluoride gas

Claims (15)

(NH ₃ ) ₃ TiF ₇ ) and an iron compound ((NH ₃ ) ₃ FeF ₆ ) by reacting titanium oxide (FeTiO ₃ ) with ammonia (NH ₃ ) gas and hydrogen fluoride (HF) gas under an inert atmosphere, (Scheme 1);
Ii) subjecting the titanium compound to a first heat treatment to produce titanium fluoride (TiF ₄ ) (scheme 2);
Iii) subjecting the titanium fluoride to a second heat treatment together with ammonia water (NH ₄ OH) under an oxidizing atmosphere to produce titania (TiO ₂ ) (Reaction Scheme 4); And
(Iv) baking the titania to produce anatase-type titania or rutile-type titania, the method comprising the steps of:
And recovering the ammonia gas and the hydrogen fluoride gas produced in the steps ii) and iii) and recirculating the ammonia gas and the hydrogen fluoride gas to the step i).
(Scheme 1)
_{FeTiO 3 (s) + 13NH 3} (g) + 13HF (g) → (NH 3) 3 TiF 7 (s) + (NH 3) 3 FeF 6 (s) + 3H 2 O (l) + 7NH 3 (g )
(Scheme 2)
(NH ₃ ) ₃ TiF ₇ (s)? TiF ₄ (s) + 3HF (g) + 3NH ₃ (g)
(Scheme 4)
_{TiF 4 (s) + 2NH 4} OH (l) + O 2 (g) → TiO 2 (s) + 2NH 3 (g) + 4HF (g) + 2H 2 O The method according to claim 1,
Wherein the step i) is carried out at a temperature of 100 to 200 ° C. The method according to claim 1,
Wherein the ammonia gas and the hydrogen fluoride gas are used in an amount of 10 to 15 moles, respectively, with respect to 1 mole of the titanate in the step i). The method according to claim 1,
Wherein ammonia gas and water are recovered from step i) and fed to step iii). The method according to claim 1,
Wherein the first heat treatment of step ii) is carried out at a temperature of 250 to 400 ° C. The method according to claim 1,
Wherein the iron compound ((NH ₃ ) ₃ FeF ₆ ) produced in the step i) is removed through a first heat treatment. The method according to claim 1,
Wherein the second heat treatment of step iii) is performed at a temperature of 450 to 750 ° C. The method according to claim 1,
Wherein the second heat treatment of step iii) is performed by injecting air or oxygen. The method according to claim 1,
Wherein the anatase-type titania is produced when the firing temperature of step (iv) is lower than 550 to 950 占 폚, and the rutile-type titania is produced when the firing temperature is 950 to 1200 占 폚. In order to selectively produce anatase-type titania or rutile-type titania as set forth in claim 1,
A first reactor for reacting titanium oxide, ammonia gas and hydrogen fluoride gas under an inert atmosphere to produce a titanium compound and an iron compound;
A second reactor that is connected to the first reactor by piping to generate titanium fluoride by first heat treating the titanium compound introduced therefrom;
A third reactor connected to the second reactor and connected to the third reactor for generating titania by performing a second heat treatment on the titanium fluoride introduced therefrom together with ammonia water under an oxidizing atmosphere;
A fourth reactor for producing anatase-type titania or rutile-type titania by firing titania introduced thereinto from a pipeline connected to the third reactor; And
And a recovering unit for collecting the anatase-type titania or the rutile-type titania that is piped to the fourth reactor and introduced thereinto, the apparatus comprising:
And a return line for collecting ammonia gas and hydrogen fluoride gas produced in the second reactor and the third reactor and supplying the collected ammonia gas and hydrogen fluoride gas to the first reactor. 11. The method of claim 10,
Wherein the ammonia gas and the hydrogen fluoride gas are supplied to the first reactor in an amount of 10 to 15 moles, respectively, relative to 1 mole of the titanate. 11. The method of claim 10,
The titania production apparatus
Further comprising a return line for withdrawing ammonia gas and water from the first reactor and supplying the recovered ammonia gas and water to a third reactor. 11. The method of claim 10,
The titania production apparatus
Further comprising a chamber for discharging the iron compound subjected to the first heat treatment in the second reactor to the outside. 11. The method of claim 10,
The titania production apparatus
Further comprising a supply line for supplying air or oxygen to the third reactor. 11. The method of claim 10,
Wherein anatase-type titania is produced when the internal temperature of the fourth reactor is lower than 550 to 950 占 폚, and rutile-type titania is produced when the calcination temperature is 950 to 1200 占 폚.

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