JPH0437004B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Object of the Invention> Industrial Application Field The present invention relates to a method and apparatus for producing ultrafine powder. Specifically, the present invention relates to a new method and apparatus for producing ultrafine powder used as a raw material for electronic materials, catalysts, pigments, and the like.

PRIOR ART Conventionally, as a method for producing ultrafine powder from a liquid phase using a substance such as an alkoxide that produces metal oxides, hydroxides, or hydrates thereof through hydrolysis, the thermal decomposition method has been used. Alternatively, the alcohydrolysis method, which is one of the precipitation methods, is known.

Problems to be Solved by the Invention The pyrolysis method is difficult to control the production process, such as the inclusion of carbon or carbide due to incomplete combustion of the solvent, and explosive combustion of gas due to pyrolysis, and the pyrolysis process involves extremely high temperatures. There was a drawback that it was not possible to obtain an oxide powder that was active at low temperatures because of the requirement.
In addition, the alkoxide hydrolysis method has traditionally been carried out under normal pressure, and is a method of obtaining oxide powder through many steps such as filtration, drying, and pulverization of the alkoxide hydrolyzate, and many of the process operations are complicated. In conventional drying methods, the particles are agglomerated and solidified, making it difficult to obtain a fine powder, which requires pulverization in some cases, and has the disadvantage that impurities such as abrasion powder from ball mills and the like are easily mixed in during the pulverization process.

<Structure of the Invention> Means for Solving the Problems The present invention focuses on the fact that the hydrolysis reaction of alkoxide is completed in an extremely short time and is based on the above-mentioned conventional manufacturing technology, and by improving this, a novel This method and device have been completed.

The first invention of the present application contains 100 to 400 metal alkoxides.
℃, hydrolyzed under high temperature and pressure of 20-2000Kg/ ^cm2 ,
By spraying immediately after this hydrolysis, the particle size can be reduced.
The present invention relates to a method for producing ultrafine particle powder, characterized in that the metal oxide, hydroxide, or hydrate thereof having a particle size of 0.1 μm or less is obtained.

In the method of the present invention, the method of hydrolyzing a metal alkoxide under high temperature and high pressure involves mixing and reacting a metal alkoxide solution with water that has been brought to a high temperature and high pressure state under the same pressure as the high temperature and high pressure water or under a state where the water is heated under pressure. Spray at high pressure. Further, recovery is performed by a method such as direct spraying together with water into the recovery section.
The collection section is connected to the nozzle in order to completely collect the hydrolysis products sprayed from the spray nozzle, and has a sealed structure on the nozzle side, and is capable of converting solvents such as water and alcohol produced by hydrolysis into liquid or vaporized form. The temperature of the collection section can be variably adjusted to maintain the same condition, and the powder can be separated either indirectly or directly.

The metal alkoxide used in the method of the present invention is preferably an alkoxide that undergoes a relatively rapid hydrolysis reaction under high temperature and high pressure and is easy to handle.Ultrafine powder of composite oxide can be obtained by using not only a single type of alkoxide but also two or more types of alkoxide. is also possible.

The second invention of the present application includes a two-line high-pressure generation section equipped with a supply pump that generates high pressure, a two-line high-temperature generation section equipped with a heat exchange heater that generates high temperature, and a metal alkoxide that is hydrolyzed and sprayed under high temperature and high pressure. An apparatus for producing ultrafine particle powder, comprising a high-temperature, high-pressure hydrolysis section, and a recovery section for recovering the metal oxide, hydroxide, or hydrate thereof produced in the hydrolysis section in powder form. Pertains to.

<<Operation>> In the method of the first invention of the present application, while taking advantage of the characteristics of the alkoxide method that yields ultrafine particles of high purity, direct hydrolytic spraying is carried out under high temperature and high pressure to accelerate the reaction rate and form a high temperature stable phase. It can be obtained more easily, and rapid expansion by spraying causes further refinement, making it possible to prevent agglomeration.
As a result, while the conventional method required many complicated steps such as filtration, drying, and pulverization after forming the precipitate in batches, the method of the present invention allows the production of highly pure and uniform particles immediately after hydrolysis. Ultrafine powder can now be produced in a short time and with fewer steps.

In the apparatus of the second invention of the present application, the process operation is easy, and ultrafine powder with extremely low impurities can be obtained.

<<Example>> For convenience, first, the manufacturing apparatus of the second invention of the present application will be described in detail with reference to the example of the drawings.

The apparatus of the present invention is comprised of a high pressure generation section 1, a high temperature generation section 2, a high temperature and high pressure hydrolysis section 3, and a recovery section 4. High pressure generating part 1 is 20~2000Kg/cm ² , 200c.c./
The system consists of a Min supply pump 11, a safety valve, and a suction tank 12 for injecting each hydrolyzate and alkoxide, and an alkoxide preparation device 13 is connected to the suction tank for alkoxide injection by a pipeline. High temperature generation part 2
The apparatus is equipped with a heat exchanger connected to the high pressure generating part 1 and having a heater capable of changing the temperature from 100 to 400°C.
The high-temperature, high-pressure hydrolysis section 3 includes a spray nozzle 15 that mixes and hydrolyzes high-temperature, high-pressure water and a high-temperature, high-pressure alkoxide solution, and sprays the mixture. The recovery section 4 is connected to the high temperature and high pressure hydrolysis section 3 and has a spray nozzle 15.
It has a cylindrical tank surrounding the spray path and corresponding to the spray flow velocity. In addition, the temperature can be variably adjusted to appropriately control the liquid or vaporized state of solvents such as water and alcohol after spraying.
As a means for this purpose, a hot air generator 16 for introducing temperature-controlled hot air was provided, and a collector 17 for collecting the powder was further connected to the end of the hot air generator 16. A cooling device 18 is installed around the collector 17 as necessary.
is installed.

Next, an embodiment of the method of the first invention using the apparatus of the second invention will be described.

The starting raw materials, alkoxides, are Ba(Obu) ₂ and Sb.
(iOPr) ₃ , Al(iOPr) ₃ , Bi(OEt) ₃ , Si(OEt) ₄ , Ti
Using alkoxides such as (iOPr) ₄ and Sn(iOPr) ₄ , one or more of the above alkoxides are dissolved in a solvent such as ethanol, isopropanol, benzene or toluene, and the concentration is adjusted to 0.01.
Adjust to about 0.1/1. Next, the prepared alkoxide solution and the hydrolysis liquid are injected into the hydrolysis part 3 under high temperature and high pressure of 20 to 2000 Kg/cm ² and 100 to 400°C by the high temperature and high pressure generation parts 1 and 2 to be hydrolyzed, and then sprayed. Spray from nozzle 15. The sprayed ultrafine powder is collected by a collector 17.

Example 1 Antimony propoxide Sb prepared using toluene solvent in alkoxide preparation device 13
(iOPr) ₃ solution prepared at a concentration of 0.1 mol/1 was prepared in the suction tank 12, and heated to 200°C, 200 Kg/cm ² , 40 mol/1 by the high temperature and high pressure generating parts 1 and 2.
It was injected into the hydrolysis section 3 under conditions of min. At the same time, decarbonate distilled water at 200℃, 200Kg/cm ² , 160ml/
The mixture was injected into the high-temperature, high-pressure hydrolysis section 3 under high-temperature and high-pressure conditions of min. Spraying is carried out by continuous operation for 30 minutes under the above conditions, and hot air whose temperature is controlled at 200°C by the hot air generator 16 is introduced into the collecting section 4 to collect the collector 17.
Ultrafine powder of antimony dioxide was directly obtained. Further, excess water, alcohol, and other solvents were collected and separated in a collector 17 by a cooling device 18. The resulting fine powder was a uniform particle powder of orthorhombic crystals, whereas the conventional method had only equiaxed crystals. Note that the particle size was 0.05 μm or less.

Example 2 A solution of aluminum isopropoxide Al (iOPr) ₃ prepared using a toluene solvent by the alkoxide preparation device 13 with a concentration of 0.05 mol/1 was prepared in the suction tank 12, and the high temperature and high pressure generating section was prepared. 200℃, 400Kg/cm ² , 30 by 1 and 2
It was injected into the hydrolysis section 3 under conditions of ml/min. At the same time, a decarboxylated ethanol aqueous solution was heated at 200℃ and 400℃.
After hydrolysis under high temperature and pressure of Kg/cm ² and 200 ml/min, it was sprayed from the spray nozzle 15. Under the above conditions
It was continuously operated for 30 minutes to spray, and then introduced into the recovery section 4 and collected by the collector 17 to obtain hydrated alumina. Note that the particle size was 0.03 μm or less.

Example 3 Titanium isopropoxide Ti prepared using benzene solvent by alkoxide preparation device 13
(iOPr) ₄ solution prepared at a concentration of 0.1 mol/1 was prepared in the suction tank 12, and a reaction was carried out under the same conditions and in the same apparatus as in Example 1. The resulting fine powder was a uniform ultrafine powder of anatase titanium oxide. Furthermore, the particle size is
It was 0.05 μm or less.

Example 4 Antimony isopropoxide prepared by alkoxide preparation device 13 using toluene solvent
Sb(iOPr) ₃ and aluminum isopropoxide Al
( _iOPr ) A complex alkoxide solution with a molar concentration ratio of 1:1 prepared at a concentration of 0.1 mol/1 was prepared in the suction tank 12, and heated at 300°C and 500 Kg/cm ² by the high temperature and high pressure generating parts 1 and 2. , into the hydrolysis section 3 under high temperature and high pressure conditions of 30 ml/min. Simultaneously decarboxylated ethanol aqueous solution at 300℃, 500Kg/cm ² ,
Hydrolysis section 3 under high temperature and high pressure conditions of 200ml/min.
After being injected into the water and hydrolyzed, it was sprayed from the spray nozzle 15. The hot air, which is sprayed continuously for 60 minutes under the above conditions and whose temperature is controlled at 250°C by the hot air generator 16, is introduced into the recovery section 4, and the collector 17 directly collects the antimony trioxide-hydrated alumina composite oxide. An ultrafine powder was obtained. In addition, excess water, alcohol, and toluene solvent are removed from the cooling device 1.
8 and collected and separated into a collector 17. As a result of chemical analysis, the resulting composite powder was found to be extremely uniform particles, and was found to be aluminum antimonate, which would be produced during calcination at 1000°C in the conventional method.
AlSbO ₄ was obtained by calcination at 800℃ on the low temperature side. Note that the particle size before calcination was 0.01 μm or less.

Example 5 Antimony isopropoxide prepared using toluene solvent by alkoxide preparation device 13
Sb (iOPr) ₃ and titanium isopropoxide Ti (iOPr) ₄
A composite alkoxide solution having a molar concentration ratio of 3:2 and a concentration of 0.1 mol/mol was prepared in suction tank 12, and a reaction was carried out under the same conditions and in the same apparatus as in Example 4. The resulting composite powder is
Similar to Example 4, the particles were extremely uniform, and the high temperature stable phase of titanium antimonate Sb ₃ Ti ₂ O ₁₀ was obtained on the low temperature side. Furthermore, the particle size is
It was 0.01 μm or less.

<<Effects of the Invention>> The ultrafine powder obtained by the first and second inventions of the present application is a uniform particle with a primary particle diameter of 0.1 μm or less, and since the alkoxide itself can be purified, it has high purity with few impurities. A powder with a uniform composition can be produced by mixing two or more types of alkoxides.

[Brief explanation of drawings]

The drawing is a schematic view showing the main part of the embodiment of the second invention device of the present application. 1... High pressure generation section, 2... High temperature generation section, 3... High temperature and high pressure hydrolysis section, 4... Recovery section, 11... Supply pump,
12... Suction tank, 13... Alkoxide preparation device, 14... Heat exchanger, 15... Spray nozzle, 1
6... Hot air generator, 17... Collector, 18... Cooling device.

Claims (1)

[Claims] 1. Metal alkoxide at 100-400℃ and 20-2000℃
It is characterized by hydrolyzing at a high temperature and pressure of Kg/cm ² and spraying immediately after the hydrolysis to obtain the metal oxide, hydroxide, or hydrate thereof having a particle size of 0.1 μm or less. Method for producing ultrafine powder. 2. High-temperature and high-pressure hydrolysis in which metal alkoxide is hydrolyzed and sprayed under high temperature and high pressure using two lines of high-pressure generation units equipped with supply pumps that generate high pressure and two lines of high-temperature generation units equipped with heat exchange heaters that generate high temperatures. 1. An apparatus for producing ultrafine particle powder, comprising: a recovery section for recovering powdered oxides, hydroxides, or hydrates of the metals produced in the hydrolysis section.