JP2006263659A - Manufacturing method and manufacturing device of inorganic microcrystal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method and manufacturing device of inorganic microcrystals capable of easily controlling the deposition condition and growth condition of the inorganic microcrystals and optimizing the manufacture condition of the inorganic microcrystals as a result by facilitating temperature control in a process of depositing a crystal nucleus and a crystal growth process of growing the crystal on the basis of the crystal nucleus, etc., at the time of continuously manufacturing the inorganic microcrystals. <P>SOLUTION: In the manufacturing method of the inorganic microcrystals, a solution or slurry to be the raw material of the inorganic microcrystals is held at a temperature (1), then, the solution or slurry held at the temperature (1) is held at a temperature (2) different from the temperature (1) to deposit the crystal nucleus, and then the crystal growth of the crystal nucleus in the solution or slurry is performed at a temperature (3). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for producing inorganic microcrystals, and in particular, when inorganic microcrystals are continuously produced by a hydrothermal synthesis method, the precipitation conditions of inorganic microcrystals are determined according to the form of hydrothermal synthesis reaction. The present invention relates to an inorganic microcrystal manufacturing method and a manufacturing apparatus that can optimize the manufacturing conditions of inorganic microcrystals by appropriate preparation.

Conventionally, there is a hydrothermal synthesis method as a widely known method for synthesizing inorganic fine particles. As a device to which this hydrothermal synthesis method is applied, a batch type hydrothermal synthesis device or a continuous hydrothermal synthesis method is used. Devices have been proposed and widely used in various fields by taking advantage of their characteristics.
In the case of synthesizing inorganic fine particles by hydrothermal synthesis method, in the process of synthesis reaction, in each stage such as generation of crystal nuclei, further crystal precipitation after crystal nucleation, improvement of crystallinity by dissolution and precipitation of crystals, It is necessary to control the temperature conditions depending on the reaction mode.

For example, the batch-type hydrothermal synthesizer described above is the time when an inorganic fine particle raw material is set in the apparatus, and then either or both of the temperature and pressure of the raw material are changed to reach the target temperature or pressure. In this case, the inorganic fine particles are synthesized by holding for a certain period of time, so that various inorganic fine particles suitable for the purpose can be appropriately synthesized by appropriately changing the synthesis conditions such as raw materials, temperature and pressure.
On the other hand, the continuous hydrothermal synthesizer was developed with a focus on increasing the efficiency of the synthesis of inorganic fine particles and reducing the production cost. Most of them are simply enlarged, batch-type synthesizers or simply continuous conditions, for example, devices that perform a hydrothermal reaction while inorganic fine particles pass through a long pipe. It has been proposed (see Patent Document 1).
JP-A-8-40723

  By the way, the conventional batch type hydrothermal synthesizer has a problem that it is difficult to quickly raise and lower the temperature in accordance with each stage such as generation of crystal nuclei and crystal growth. In addition, there is a problem that it takes a long time to obtain fine particles. Moreover, since it is a batch type, the amount of inorganic fine particles obtained by one operation is naturally limited, and there is a problem that it is difficult to obtain a certain amount or more of inorganic fine particles at a low cost.

Moreover, in the continuous hydrothermal synthesizer, the hydrothermal reaction is carried out while the inorganic fine particle raw material passes through the pipe, so the reaction time of the hydrothermal reaction becomes longer and the total length of the pipe becomes longer. Therefore, there is a problem that it is difficult to perform delicate temperature control. In addition, there are problems in that the solution or slurry as a raw material is fed in, the temperature of each part of the piping is controlled, and the solution or slurry is stirred in the piping.
In this way, by continuing the hydrothermal synthesis reaction, it becomes possible to easily control the temperature of the raw material solution or slurry, or the reaction or synthesis solution or slurry, but the generation of crystal nuclei and crystals At present, temperature control at each stage in hydrothermal synthesis such as growth cannot be precisely controlled.

  The present invention has been made in order to solve the above-described problems. In the continuous production of inorganic microcrystals, in the process of precipitation of crystal nuclei, the process of crystal growth of growing crystals based on the crystal nuclei, etc. By making the temperature control easy, it is possible to easily control the deposition conditions and growth conditions of inorganic microcrystals, and as a result, it is possible to optimize the manufacturing conditions of inorganic microcrystals. And it aims at providing a manufacturing apparatus.

  As a result of intensive studies on a method and an apparatus for continuously producing inorganic microcrystals by a hydrothermal synthesis method, the present inventors once held a solution or slurry as a raw material for inorganic microcrystals at a predetermined temperature, and then By precipitating crystal nuclei by two-stage temperature control of heating or cooling the solution or slurry, it becomes easy to appropriately adjust the precipitation conditions of inorganic microcrystals. By growing the crystal nucleus at a desired temperature, it becomes easy to appropriately adjust the growth conditions of the inorganic microcrystals, and as a result, it has been found that the manufacturing conditions of the inorganic microcrystals can be optimized. The present invention has been completed.

  That is, the method for producing inorganic microcrystals of the present invention is a method for continuously producing inorganic microcrystals, in which a solution or slurry as a raw material for inorganic microcrystals is held at temperature (1), and then The solution or slurry held at the temperature (1) is held at a temperature (2) different from the temperature (1) to precipitate crystal nuclei, and then the crystal nuclei in the solution or slurry are heated at the temperature (3). It is characterized by crystal growth.

  In this method for producing inorganic microcrystals, a solution or slurry as a raw material for inorganic microcrystals is held at temperature (1), and then the solution or slurry held at this temperature (1) is heated to the temperature (1). The temperature control of the crystal nucleus precipitation process is performed in two stages, such as holding the crystal nucleus at different temperatures (2), and the temperature control in the crystal nucleus precipitation process of the inorganic microcrystal becomes easy. The crystallinity of the crystallites generated through the crystallite dissolution and precipitation process is improved. This makes it possible to easily control the precipitation conditions of the crystal nuclei of the inorganic microcrystal.

In the method for producing inorganic microcrystals of the present invention, the solution or slurry containing the crystal nuclei is held at a temperature (4) different from the temperature (2), and then the crystal nuclei in the solution or slurry are heated to a temperature. Crystal growth may be performed in (3).
In this method for producing inorganic microcrystals, the solution or slurry containing the crystal nuclei is held at a temperature (4) different from the temperature (2), and then the crystal nuclei in the solution or slurry are brought to a temperature (3). By crystal growth, the temperature control of the solution or slurry containing crystal nuclei is performed in two stages, and the temperature control in the crystal growth process of the inorganic microcrystal becomes easy. This makes it possible to easily control the crystal growth conditions of the inorganic microcrystal.

In the method for producing inorganic microcrystals of the present invention, the temperature (1) is −80 ° C. or more and 300 ° C. or less, the temperature (2) is higher than the temperature (1) and is room temperature or more and 800 ° C. or less, It is preferable that the temperature (3) is −80 ° C. or higher and the temperature (2) or lower.
By controlling the temperatures (1) to (3) as described above, the temperature control in the precipitation process of the crystal nuclei of the inorganic microcrystal and the temperature control in the crystal growth process are facilitated. This makes it possible to easily control the crystal nucleus precipitation conditions and crystal growth conditions of the inorganic microcrystal.
In particular, if the temperature change between the temperature (1) and the temperature (2) is made steep, it is possible to produce microcrystals at the crystal nucleus generation stage of the inorganic microcrystals.

In the method for producing an inorganic microcrystal of the present invention, the temperature (1) is not less than room temperature and not more than 800 ° C., the temperature (2) is lower than the temperature (1) and is not less than −80 ° C. and not more than 300 ° C., 3) may be set to −80 ° C. or higher and the temperature (1) or lower.
By controlling the temperatures (1) to (3) as described above, the temperature control in the precipitation process of the crystal nuclei of the inorganic microcrystal and the temperature control in the crystal growth process are facilitated. This makes it possible to easily control the crystal nucleus precipitation conditions and crystal growth conditions of the inorganic microcrystal.
In particular, if the temperature change between the temperature (1) and the temperature (2) is made steep, it is possible to produce microcrystals at the crystal nucleus generation stage of the inorganic microcrystals.

  The apparatus for producing inorganic microcrystals of the present invention is an apparatus for continuously producing inorganic microcrystals, the supply means for supplying a solution or slurry as a raw material for inorganic microcrystals, and the supply means supplied by the supply means A temperature holding unit for holding the solution or slurry at a temperature (1), and a crystal nucleus for precipitating a crystal nucleus by holding the solution or slurry fed from the temperature holding unit at a temperature (2) different from the temperature (1) It is characterized by comprising a precipitation part and a crystal growth part for crystal growth of the crystal nucleus by maintaining a solution or slurry containing the crystal nucleus delivered from the crystal nucleus precipitation part at a temperature (3).

  In this inorganic microcrystal manufacturing apparatus, after the solution or slurry supplied by the supply means is held at the temperature (1) in the temperature holding unit, the solution sent out from the temperature holding unit or By keeping the slurry at a temperature (2) different from the temperature (1) and precipitating crystal nuclei, it becomes possible to control the temperature of the crystal nucleation process in two stages. Temperature control during the precipitation process is facilitated. This makes it possible to easily control the shape and size of the crystal nucleus of the inorganic microcrystal.

  In addition, the shape and size of the crystal growth part were controlled by maintaining the solution or slurry containing the crystal nucleus delivered from the crystal nucleus precipitation part at the temperature (3) and growing the crystal nucleus in the crystal growth part. Crystal growth is performed based on the crystal nucleus, and inorganic microcrystals having a controlled shape and size can be continuously produced.

  The apparatus for producing inorganic microcrystals of the present invention includes a second temperature holding unit that holds a solution or slurry containing crystal nuclei sent out from the crystal nucleus precipitation unit at a temperature (4) different from the temperature (2), A solution or slurry containing crystal nuclei sent out from the second temperature holding unit may be sent into the crystal growth unit.

  In this inorganic microcrystal manufacturing apparatus, the second temperature holding unit holds a solution or slurry containing crystal nuclei at a temperature (4) different from the temperature (2), and then the crystal growth unit By keeping the solution or slurry containing crystal nuclei sent out from the temperature holding part 2 at the temperature (3) and precipitating the crystal nuclei, it becomes possible to control the temperature of the crystal growth process in two stages Temperature control in the crystal growth process of the microcrystal becomes easy. This makes it possible to easily control the shape and size of the inorganic microcrystal.

  The apparatus for producing inorganic microcrystals of the present invention further includes the temperature (1) of −80 ° C. or more and 300 ° C. or less, the temperature (2) higher than the temperature (1), the room temperature or more and 800 ° C. or less, It is preferable that the temperature (3) is −80 ° C. or higher and the temperature (2) or lower.

  By controlling the temperatures (1) to (3) as described above, the temperature control in the precipitation process of the crystal nuclei of the inorganic microcrystal and the temperature control in the crystal growth process are facilitated. This makes it possible to easily control the crystal nucleus precipitation conditions and crystal growth conditions of the inorganic microcrystal.

  In the apparatus for producing inorganic microcrystals of the present invention, the temperature (1) is not less than room temperature and not more than 800 ° C., the temperature (2) is lower than the temperature (1), not less than −80 ° C. and not more than 300 ° C., and the temperature ( 3) may be set to −80 ° C. or higher and the temperature (1) or lower.

  By controlling the temperatures (1) to (3) as described above, the temperature control in the precipitation process of the crystal nuclei of the inorganic microcrystal and the temperature control in the crystal growth process are facilitated. This makes it possible to easily control the crystal nucleus precipitation conditions and crystal growth conditions of the inorganic microcrystal.

The apparatus for producing inorganic microcrystals of the present invention may further comprise a pressure control means for controlling the pressure inside the crystal growth part in the crystal growth part.
In this apparatus for producing an inorganic microcrystal, pressure control in the crystal growth process is facilitated by providing the crystal growth part with a pressure control means for controlling the pressure inside the crystal growth part. This makes it possible to easily control the growth conditions for crystal growth of the inorganic microcrystal.

  According to the method for producing inorganic microcrystals of the present invention, a solution or slurry that is a raw material for inorganic microcrystals is held at temperature (1), and then the solution or slurry held at this temperature (1) is heated to the temperature. Crystal nuclei are precipitated by maintaining the temperature (2) different from (1), and then the crystal nuclei in this solution or slurry are grown at temperature (3). It can be carried out in stages, and temperature control in the precipitation process of crystal nuclei of inorganic microcrystals can be easily performed. Therefore, it is possible to easily control the crystal nucleus precipitation conditions of the inorganic microcrystal, and as a result, the crystal growth of the inorganic microcrystal can be made uniform, and the shape and size of the inorganic microcrystal can be easily controlled. be able to.

  According to the apparatus for producing inorganic microcrystals of the present invention, a supply means for supplying a solution or slurry as a raw material for inorganic microcrystals, and a temperature at which the solution or slurry supplied by the supply means is maintained at temperature (1). A holding part, a crystal nucleus precipitation part for precipitating crystal nuclei by holding the solution or slurry delivered from the temperature holding part at a temperature (2) different from the temperature (1), and a crystal nucleus precipitation part. Since a crystal growth part for crystal growth of the crystal nuclei by holding the solution or slurry containing the crystal nuclei at temperature (3) is provided, it is possible to continuously produce inorganic microcrystals having a controlled shape and size. Can do.

Embodiments of the method and apparatus for producing inorganic microcrystals of the present invention will be described.
These forms are specifically described for better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified.

“First Embodiment”
FIG. 1 is a schematic configuration diagram showing an inorganic microcrystal manufacturing apparatus according to a first embodiment of the present invention, which is an apparatus for continuously manufacturing inorganic microcrystals whose shape and size are controlled.
In the figure, 1 is a raw material tank (storage tank) for storing a solution (or slurry) S as a raw material for inorganic microcrystals, 2 is a pipe for conveying the solution (or slurry) S, 3 is a raw material provided in the pipe 2 The pump supplies a solution (or slurry) S stored in the tank 1, and the raw material supply section (supply means) 4 is configured by the raw material tank 1, the pipe 2 and the pump 3.

  Also, 5 is a pipe connected to the outlet side of the pump 3, and 6 is a temperature (1) of a solution (or slurry) S sent from the pump 3 and flowing in the pipe 5, for example, −80 ° C. or more and 300 ° C. or less. A low temperature part (temperature holding part) for holding at a temperature of 7 is a temperature (2) different from the temperature (1) for the solution (or slurry) S sent from the low temperature part 6, for example, higher than the temperature (1) and above room temperature In addition, it is a crystal nucleus precipitation portion that precipitates crystal nuclei while maintaining a high temperature of 800 ° C. or less, and a temperature gradient is formed in the pipe 5 by the low temperature portion 6 and the crystal nucleus precipitation portion 7, thereby flowing in the pipe 5. When the temperature of the solution (or slurry) S to be changed rapidly changes, the solution (or slurry) S chemically reacts to generate crystal nuclei.

Reference numeral 8 denotes a solution (or slurry) S ′ containing crystal nuclei sent out from the crystal nucleation precipitation unit 7 at a temperature (3), for example, −80 ° C. or higher and temperature (2) or lower, so It is a sealed reaction tank composed of an autoclave vessel or the like that grows into crystals of a uniform shape.
The reaction vessel 8 includes a stirrer 11 for stirring a solution (or slurry) S ′ containing crystal nuclei, a heater 12 for heating and holding the solution (or slurry) S ′ containing crystal nuclei at a temperature (3), and a reaction vessel. An Ar cylinder 13 for making the inside of an argon (Ar) gas atmosphere at a predetermined pressure inside 8 and a pressure gauge 14 for measuring the pressure of Ar gas are provided.

Further, 21 is a pipe for transporting a solution (or slurry) S ″ containing inorganic microcrystals grown to a predetermined size and shape in the reaction tank 8, 22 is a check valve provided in the pipe 21, and 23 is Back pressure valve 24 is a pipe 21, a container for collecting a solution (or slurry) S ″ containing inorganic microcrystals flowing out via check valve 22 and back pressure valve 23, and 25 is a pipe communicating with pipe 21 A water tank 27 is provided at the end of 26 to store pure water, and 27 is a pump.
In this manufacturing apparatus, each operation from the raw material tank 1 to the pump 27 is controlled by a control device (not shown).
This manufacturing apparatus is isolated from the external atmosphere until the solution (or slurry) is sent out from the raw material tank 1 and then collected in the container 24 via the pipes 2 and 5, the reaction tank 8 and the pipe 21. It is a closed reaction system.

  In this apparatus for producing inorganic microcrystals, the low temperature part 6 only needs to be able to maintain the solution (or slurry) S at the temperature (1). For example, a heater for heating is provided on the outer periphery of the double tube. A wound tubular reactor is preferred. By using a double tube with a heater, it becomes easy to control the temperature of the solution (or slurry) S in a wide temperature range. The temperature of the low temperature part 6 is not particularly limited, but the lower limit temperature is −80 ° C., which is a temperature that can be reached by a cryogen composed of dry ice and ethanol, and the upper limit temperature is generally transmitted. It is preferable to set it as 300 degreeC which is the heat-resistant temperature of the organic solvent used as a heat medium.

  The low temperature part 6 and the crystal nucleus precipitation part 7 are preferably adjacent to each other. In addition, when the diameter of the pipe 5 that communicates the low temperature part 6 and the crystal nucleus precipitation part 7 is sufficiently thin, cooling or heating is easy, and the temperature gradient with respect to the solution (or slurry) S flowing through the pipe 5 is easily achieved. In addition, it is possible to easily change the temperature gradient, so that it is possible to generate microcrystals accompanying a rapid temperature change in the crystal nucleus generation stage.

Further, the temperature range of the crystal nucleus precipitation part 7 is not particularly limited as long as it is a temperature range in which crystal nuclei can be precipitated. A range from room temperature (25 ° C.) to 800 ° C. which is the upper limit of the heat resistant temperature of stainless steel is preferable.
Further, the temperature range of the reaction vessel 8 may be a temperature range in which crystal nuclei can be grown into crystals having a predetermined size and shape, and is specifically limited as in the low temperature portion 6 and the crystal nucleus precipitation portion 7. Although it is not a thing, it can set from -80 degreeC to 800 degreeC by employ | adopting either the method of heating and cooling.

Next, a method for producing inorganic fine crystals using this inorganic fine crystal production apparatus will be described.
First, a solution (or slurry) S to be a raw material for inorganic microcrystals is prepared and stored in the raw material tank 1.
Next, this solution (or slurry) S is quantitatively supplied to the low temperature part 6 through the pipe 2 and the pump 3, and maintained at a temperature (1), for example, a temperature of −80 ° C. or higher and 300 ° C. or lower.

  Here, if the solution (or slurry) S is cooled using a cryogen comprising dry ice and ethanol, it can be cooled to −80 ° C. or its vicinity. Moreover, if the solution (or slurry) S is heated with a heater, it can be heated to 300 ° C., which is the heat resistant temperature of the organic solvent.

Next, the solution (or slurry) S sent out from the low temperature part 6 is moved to the crystal nucleus precipitation part 7, and a temperature (2) different from the temperature (1), for example, higher than the temperature (1) and above room temperature and 800 ° C. The solution (or slurry) S is maintained at the following high temperature to cause a chemical reaction, and crystal nuclei serving as nuclei of inorganic microcrystals are precipitated in the solution (or slurry) S.
Since there is a steep temperature gradient between the low temperature part 6 and the crystal nucleus precipitation part 7, the solution (or slurry) S passing through it has instantaneously formed very small crystal nuclei due to a rapid chemical reaction due to a rapid temperature change. In addition, a large amount is generated.

  The solution (or slurry) S ′ containing fine crystal nuclei generated in this way is sent into the reaction vessel 8. Since the inside of the reaction vessel 8 is set to an Ar gas atmosphere at a predetermined pressure by the Ar cylinder 13 and the pressure gauge 14, the solution (or slurry) S 'is not likely to be altered by oxidation or the like.

The solution (or slurry) S ′ is stirred by the stirrer 11 and simultaneously heated and held at a temperature (3), for example, −80 ° C. or more and the temperature (2) or less by the heater 12.
At the same time, the atmosphere inside the reaction vessel 8 is maintained in an Ar atmosphere of, for example, 0.1 to 30 MPa by the Ar cylinder 13 and the pressure gauge 14.
Here, the temperature (3) is preferably equal to or lower than the temperature (2) because it is necessary to gradually grow the crystal to a uniform size and shape on the basis of the minute crystal nucleus.

By aging the solution (or slurry) S ′ containing the crystal nuclei in the reaction vessel 8 for a predetermined time, the crystal nuclei grow into crystals and become inorganic microcrystals having a predetermined size and shape.
Here, since the temperature, atmosphere and pressure during ripening are kept constant, inorganic microcrystals can be produced easily, in large quantities, and continuously based on minute crystal nuclei.

  The solution (or slurry) S ″ containing inorganic microcrystals is mixed with pure water sent from the water tank 25 after passing through the pipe 21 and the check valve 22, and recovered in the container 24 via the back pressure valve 23. By restricting the back pressure valve 23, the pressure of the entire reaction system from the pipe 2 to the pipe 22 can be arbitrarily controlled.

The solution (or slurry) S ″ containing the inorganic microcrystals may be used as it is, and when the inorganic microcrystals are used alone, the inorganic microcrystals can be used as a solution (or by ultrafiltration) or the like. The slurry may be separated from S ″ and then dried by vacuum drying or the like.
As described above, fine inorganic microcrystals or a solution (or slurry) S ″ containing fine inorganic microcrystals can be continuously produced.
Moreover, since the apparatus configuration is simple and inexpensive, the manufacturing cost can be greatly reduced.

According to this embodiment, the temperature condition in the crystal nucleus generation stage and the temperature condition in the crystal nucleus growth stage, which could not be achieved in the powder synthesis by the conventional hydrothermal synthesis reaction, and the temperature condition in the crystal nucleus growth stage are set independently of each other. Can do. Therefore, the crystallite size and crystallinity control of the obtained inorganic microcrystals are diversified as compared with the prior art, and a large amount of inorganic microcrystals controlled in size and shape can be easily produced.
Powder synthesis using the solution (or slurry) S of this embodiment as a raw material is applicable to hydrothermal synthesis for synthesizing powders of various metal oxides, phosphoric acid compounds, oxalic acid compounds, hydroxides and the like.

“Second Embodiment”
FIG. 2 is a schematic configuration diagram showing an inorganic microcrystal manufacturing apparatus according to a second embodiment of the present invention. The manufacturing apparatus according to the present embodiment is different from the manufacturing apparatus according to the first embodiment described above. In the manufacturing apparatus of the first embodiment, the reaction tank 8 is provided after the crystal nucleus precipitation part 7, whereas in the manufacturing apparatus of this embodiment, the crystal nucleus is between the crystal nucleus precipitation part 7 and the reaction tank 8. This is the point that a low temperature part (second temperature holding part) 31 for holding the solution (or slurry) S ′ containing crystal nuclei sent out from the precipitation part 7 at a temperature (4) different from the temperature (2) is provided.

The temperature (4) of the low temperature part 31 may be set as appropriate depending on the type and size of crystal nuclei to be generated, and may be a temperature different from the temperature (2). For example, it may be the same as or different from the temperature (1) of the low temperature part 6.
In this manufacturing apparatus, by setting the temperature (4) of the low temperature part 31 to be equal to or lower than the temperature (2) of the crystal nucleus precipitation part 7, the solution (or slurry) S ′ containing minute crystal nuclei is once in the low temperature part 31. After cooling, the growth of crystal nuclei in the growth process is temporarily stopped, so that a solution (or slurry) S ′ containing very fine crystal nuclei is fed into the reaction vessel 8. Therefore, in the reaction vessel 8, since the solution (or slurry) S ′ containing extremely fine crystal nuclei is aged, inorganic microcrystals excellent in monodispersity can be easily generated.

“Third Embodiment”
FIG. 3 is a schematic configuration diagram showing an inorganic microcrystal manufacturing apparatus according to the third embodiment of the present invention. The manufacturing apparatus according to the present embodiment is different from the manufacturing apparatus according to the first embodiment described above. In the manufacturing apparatus of one embodiment, after the low temperature part 6 that holds the solution (or slurry) S at the temperature (1), the solution (or slurry) S is held at a temperature higher than the temperature (1) to form crystal nuclei. Whereas the crystal nucleus precipitation part 7 for precipitation is provided, in the manufacturing apparatus of this embodiment, the solution (or slurry) S is heated after the high temperature part (temperature holding part) 41 that holds the high temperature (1). The crystal nucleus precipitation part 42 for cooling the solution (or slurry) S to a temperature (2) lower than the temperature (1) to precipitate crystal nuclei is provided.

In this manufacturing apparatus, the solution (or slurry) S is heated and held at a temperature (1) not lower than room temperature (25 ° C.) and not higher than 800 ° C. by a heating device such as a heater in the high-temperature part 41. ) Dissolve S. Next, by cooling the solution (or slurry) S to a temperature (2) lower than the temperature (1) and not lower than −80 ° C. and not higher than 300 ° C. by air cooling, water cooling, etc. in the crystal nucleus precipitation part 42, Crystal nuclei are precipitated.
As described above, since there is a steep temperature gradient between the high temperature portion 41 and the crystal nucleus precipitation portion 42, the solution (or slurry) S passing through the high temperature portion 41 and the crystal nucleus precipitation portion 42 is extremely affected by a sudden chemical reaction stop due to a sudden temperature change. A small amount of crystal nuclei are generated instantaneously and in large quantities.
Also in this manufacturing apparatus, inorganic microcrystals excellent in monodispersity can be easily generated.

“Fourth Embodiment”
FIG. 4 is a schematic configuration diagram showing an inorganic microcrystal manufacturing apparatus according to the fourth embodiment of the present invention. The manufacturing apparatus according to the present embodiment is different from the manufacturing apparatus according to the third embodiment described above. In the manufacturing apparatus of the third embodiment, the reaction tank 8 is provided after the crystal nucleus precipitation part 42, whereas in the manufacturing apparatus of the present embodiment, the crystal nucleus is between the crystal nucleus precipitation part 42 and the reaction tank 8. The high temperature part (second temperature holding part) 51 for holding the solution (or slurry) S ′ containing crystal nuclei sent out from the precipitation part 42 at a temperature (4) different from the temperature (2) is provided.

The temperature (4) of the high temperature part 51 may be appropriately set depending on the type and size of the crystal nucleus to be generated, and may be a temperature different from the temperature (2). For example, it may be the same as or different from the temperature (1) of the high temperature part 41.
In this manufacturing apparatus, the temperature (4) of the high temperature part 51 is set to be equal to or higher than the temperature (2) of the crystal nucleus precipitation part 42, so that the solution (or slurry) S ′ containing minute crystal nuclei is again in the high temperature part 51. It is heated and sent to the reaction vessel 8 while suppressing further growth of fine crystal nuclei. Accordingly, since the solution (or slurry) S ′ containing minute crystal nuclei is aged in the reaction vessel 8, inorganic crystallites having high crystallinity and excellent monodispersibility can be easily generated. .

  The method and apparatus for producing an inorganic microcrystal of the present invention facilitates temperature control in a crystal nucleus precipitation process, a crystal growth process for crystal growth based on the crystal nucleus, etc. Since the conditions can be easily controlled, it can be applied to the synthesis of various inorganic microcrystals to which the hydrothermal synthesis method is applied, and its industrial value is extremely large.

It is a schematic block diagram which shows the manufacturing apparatus of the inorganic microcrystal of the 1st Embodiment of this invention. It is a schematic block diagram which shows the manufacturing apparatus of the inorganic microcrystal of the 2nd Embodiment of this invention. It is a schematic block diagram which shows the manufacturing apparatus of the inorganic microcrystal of the 3rd Embodiment of this invention. It is a schematic block diagram which shows the manufacturing apparatus of the inorganic microcrystal of the 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Raw material tank 2 Piping 3 Pump 4 Raw material supply part 5 Piping 6 Low temperature part 7 Crystal nucleus precipitation part 8 Reaction tank 11 Stirrer 12 Heater 13 Ar cylinder 14 Pressure gauge 21 Piping 22 Check valve 23 Back pressure valve 24 Container 25 Water tank 26 Piping 27 Pump 31 Low temperature part 41 High temperature part 42 Crystal nucleus precipitation part 51 High temperature part

Claims (9)

A method for continuously producing inorganic microcrystals,
The solution or slurry that is the raw material of the inorganic microcrystal is held at the temperature (1), and then the solution or slurry held at this temperature (1) is held at a temperature (2) different from the temperature (1). A method for producing inorganic microcrystals, characterized in that crystal nuclei are precipitated and then crystal nuclei in this solution or slurry are grown at a temperature (3).   The solution or slurry containing the crystal nuclei is maintained at a temperature (4) different from the temperature (2), and then the crystal nuclei in the solution or slurry are grown at the temperature (3). The method for producing inorganic microcrystals according to claim 1.   The temperature (1) is −80 ° C. or more and 300 ° C. or less, the temperature (2) is higher than the temperature (1) and is room temperature or more and 800 ° C. or less, the temperature (3) is −80 ° C. or more and the temperature ( 2) The method for producing inorganic microcrystals according to claim 1 or 2, wherein:   The temperature (1) is not less than room temperature and not more than 800 ° C., the temperature (2) is lower than the temperature (1) and is not less than −80 ° C. and not more than 300 ° C., the temperature (3) is not less than −80 ° C. and the temperature ( 1) The method for producing inorganic microcrystals according to claim 1 or 2, wherein: An apparatus for continuously producing inorganic microcrystals,
Supply means for supplying a solution or slurry as a raw material for inorganic microcrystals, a temperature holding section for holding the solution or slurry supplied by the supply means at a temperature (1), and the solution fed from the temperature holding section Alternatively, a solution or slurry containing a crystal nucleus precipitation part for precipitating crystal nuclei by holding the slurry at a temperature (2) different from the temperature (1) and a crystal nucleus sent out from the crystal nucleus precipitation part at temperature (3) An apparatus for producing inorganic microcrystals, comprising: a crystal growth unit that holds and grows the crystal nucleus. A second temperature holding unit that holds a solution or slurry containing crystal nuclei delivered from the crystal nucleus precipitation unit at a temperature (4) different from the temperature (2);
6. The inorganic microcrystal manufacturing apparatus according to claim 5, wherein a solution or slurry containing crystal nuclei sent out from the second temperature holding unit is fed into the crystal growth unit.   The temperature (1) is −80 ° C. or more and 300 ° C. or less, the temperature (2) is higher than the temperature (1) and is room temperature or more and 800 ° C. or less, the temperature (3) is −80 ° C. or more and the temperature ( 2) The apparatus for producing inorganic microcrystals according to claim 5 or 6, wherein:   The temperature (1) is not less than room temperature and not more than 800 ° C., the temperature (2) is lower than the temperature (1) and is not less than −80 ° C. and not more than 300 ° C., the temperature (3) is not less than −80 ° C. and the temperature ( 1) The apparatus for producing inorganic microcrystals according to claim 5 or 6, wherein:   The apparatus for producing inorganic microcrystals according to any one of claims 5 to 8, wherein the crystal growth part is provided with pressure control means for controlling the pressure inside the crystal growth part.

Images