JP2023005870A - Manufacturing method of zeolite and manufacturing apparatus - Google Patents

Abstract

To provide a manufacturing method capable of manufacturing high quality zeolite by making it easy to control a reaction time by rapidly crashing blocks of zeolite formed when the zeolite is manufactured by a sealed heating of a static state without using OSDA, at the same time, capable of easily taking out to the outside of a reactor, and capable of combining high quality, yield improvement and manufacturing cost reduction.SOLUTION: A production method of the present invention includes a first step of heating a reaction mixture and seed crystals in a reaction vessel and allowing them to react in a stationary state, and a second step of discharging the produced massive zeolite out of the reaction vessel. A bottom surface of the reaction vessel is funnel-shaped with an inclined surface inclined downward toward the outlet of the zeolite, and a stirring member of the reaction vessel has a first stirring blade having an edge extending along the inclined surface of the reaction vessel and a second stirring blade on its upper part, the inclined surface and the edge of the first stirring blade are in a non-contact state, and in the second step, the first stirring blade and the second stirring blade fluidize the zeolite and discharged from the outlet.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing zeolite without using an organic structure directing agent (OSDA) and a zeolite production apparatus suitable for the method.

A method for producing zeolite without using OSDA is known (Patent Document 1). In the method described in Patent Document 1, seed crystals are mixed with a reaction mixture consisting of a silica source, an alumina source, an alkali source and water to produce zeolite under high temperature and pressure conditions. The reaction mixture contains a solid phase aluminosilicate gel and a liquid phase alkaline aqueous solution. Patent Document 1 describes, as a method for producing zeolite without using OSDA, a method in which a reaction mixture and seed crystals are heated and reacted in a stationary state without stirring.

International publication 2011/013560 pamphlet

A high-quality zeolite can be obtained at a high yield by raising the temperature of the reaction mixture containing the seed crystals to a predetermined temperature in a stationary state and reacting the mixture for a predetermined period of time.
In the step of heating the reaction mixture mixed with the seed crystals, the reaction does not occur or is extremely slow, so that the mixture can be stirred and mixed, so that the temperature can be raised quickly. After reaching the reaction temperature, when the reaction is allowed to stand, the solid phase portion of the reaction mixture settles in the lower part of the reaction vessel and is gradually dissolved in the upper liquid phase of the alkaline aqueous solution. Produces zeolites.
However, the method of heating and reacting the reaction mixture and seed crystals in a stationary state has the following problems.
In order to control the reaction time, it is necessary to control the cooling rate of the zeolite after completion of the reaction. A cake of zeolite crystals deposited at the bottom of the reaction vessel at the end of the reaction tends to solidify in a cake-like deposit state. If the cake remains as it is, the solid heat is transferred from the external cooling surface, and the overall heat transfer coefficient is small, resulting in slow cooling, making it difficult to control the reaction time. In addition, scaling up reduces the specific surface area, making it even more difficult to control the cooling rate. If the reaction time cannot be controlled accurately, side reactions will occur, leading to contamination of impurities such as formation of zeolites other than the desired zeolite.
In addition, the zeolite crystal cake tends to adhere to the inner wall surface of the reaction vessel, although the reason is not clear, and is difficult to remove. As a result, the yield is lowered, and the processing cost for washing the reaction vessel with an alkaline solution to dissolve and remove the adhering zeolite crystals is high. These are important problems to be solved in industrial production where cost and environmental issues are important. On the other hand, if the inner wall surface of the reaction vessel is treated to impart a peeling effect, the entire cake will idle when the stirring blade is rotated, making it more difficult to crush the cake.

SUMMARY OF THE INVENTION An object of the present invention is to provide a zeolite manufacturing method and manufacturing apparatus that can overcome the various drawbacks of the prior art described above.
That is, the present invention is a method for producing high-quality and inexpensive zeolite by crushing and fluidizing the cake of zeolite crystals deposited at the bottom of the reactor in a short time and by enabling accurate control of the reaction time. and its manufacturing equipment.

In the present invention, a zeolite raw material containing a reaction mixture containing a silica source, an alumina source, an alkali source, water, and not containing an organic structure-directing agent, and seed crystals is heated and allowed to stand in a closed reaction vessel. A first step of reacting in a state;
A method for producing zeolite, comprising:
The reaction vessel has a discharge port for discharging zeolite at the bottom, and the bottom surface of the bottom is formed in a funnel shape having a downward inclined surface toward the discharge port,
The reaction vessel has a stirring member,
The stirring member includes a rotating shaft that is positioned at the center of the funnel-shaped bottom surface and extends vertically when the reaction vessel is viewed from above, and a rotating shaft that is attached to the rotating shaft and extends along the inclined surface of the reaction vessel. A first impeller having an edge and a second impeller attached to the top of the first impeller on the rotating shaft,
The inclined surface of the bottom of the reaction vessel and the edge of the first stirring blade are in a non-contact state,
A method for producing zeolite, wherein in the second step, the rotating shaft is rotated to fluidize the zeolite with the first stirring blade and the second stirring blade, and the fluidized zeolite is discharged from the discharge port. is.

The present invention also provides a production apparatus for producing zeolite without using an organic structure-directing agent,
It has a reaction vessel capable of heating a zeolite raw material in a sealed state, and a stirring member that can be accommodated in the reaction vessel,
The reaction vessel has a discharge port for discharging the fluidized zeolite at the bottom, and the bottom surface of the bottom is formed in a funnel shape having an inclined surface inclined toward the discharge port,
The stirring member includes a rotating shaft positioned at the center of the funnel-shaped bottom surface when viewed from above and extending in the vertical direction, and an edge attached to the rotating shaft and extending along the inclined surface of the reaction vessel. and a second stirring blade attached to the upper part of the first stirring blade on the rotating shaft, the inclined surface at the bottom of the reaction vessel, and the first The object of the present invention is to provide a manufacturing apparatus that is in a non-contact state with the edge of the stirring blade.

According to the present invention, even when zeolite is produced by closed heating in a stationary state without using OSDA, the lumped zeolite can be easily taken out of the reaction vessel 20, and the production cost can be reduced. It is possible to provide a zeolite production method and a production method capable of producing high-quality zeolite. The stirring member used in the present invention can be housed in an autoclave, can be used for mixing the reaction mixture and seed crystals, and exhibits excellent effects due to its relatively simple structure.

FIG. 1 is a partially cutaway front view showing a zeolite manufacturing apparatus according to one embodiment of the present invention. FIG. 2(a) is a perspective view showing a stirring member of the zeolite manufacturing apparatus of FIG. FIG. 2(b) is an end view of the stirring member cut along line AA of FIG. 2(a), and FIG. 2(c) is a stirring member along line BB of FIG. 2(a). It is the end view which cut|disconnected the member. FIG. 3 is a graph of measured shear stress and shear rate of zeolite slurry. FIG. 4 is a schematic diagram showing one aspect of the zeolite production method using the zeolite production apparatus of FIG. It shows the process of decomposing and discharging. FIG. 5 is a perspective view showing a stirring member of an embodiment different from FIG. 2(a). FIG. 6 is a cross-sectional view of a reaction vessel used in a comparative example. FIGS. 7A and 7B are perspective views of stirring members used in comparative examples.

Preferred embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the zeolite production apparatus 10 used in the present embodiment is an autoclave apparatus, and includes a reaction vessel 20 capable of heating the zeolite raw material in a sealed state, and a stirring member 30 that can be accommodated in the reaction vessel 20. have.

As shown in FIG. 1, the zeolite manufacturing apparatus 10 constitutes a reaction vessel 20 in which the zeolite raw material is stored as it is. That is, in the manufacturing apparatus 10, the reaction vessel 20 may be detachably installed on the can body, or may be irremovably installed on the can body. Such a structure of the zeolite manufacturing apparatus 10 is preferable in that the heat of the heated can body (reaction vessel 20) is directly transmitted to the zeolite raw material, making it easy to control the temperature of the zeolite raw material and to easily obtain high-quality zeolite. The reaction vessel 20 is preferably made of stainless steel or the like.

A lid body 24 is installed in the reaction vessel 20 so as to be openable and closable. The zeolite raw material in the reaction vessel 20 is heated by circulating a heating medium or steam through a pipe (not shown) in a jacket 26 provided on the outer periphery of the reaction vessel 20 .

As shown in FIG. 1, reaction vessel 20 has outlet 22 at bottom 21 for discharging the zeolite. The bottom 21 of the reaction vessel 20 has a funnel-shaped bottom 23 . The bottom surface 23 has an inclined surface 23 a inclined downward toward the discharge port 22 . The funnel shape as used herein includes a conical shape. The inclined surface 23a is flat when the reaction vessel 20 is viewed from the side. The inclined surface 23 a is continuous with the discharge port 22 . When the reaction vessel 20 is viewed from the side, the inclined surface 23a has an angle of 5° or more and 70° or less with respect to the horizontal plane (angle α in FIG. 1). and more preferably 30° or more and 50° or less. In particular, it is preferable that the angle α is larger than 42°, because the fluidity is high and the discharge efficiency can be reliably improved. Note that the horizontal plane refers to a plane perpendicular to the vertical direction in which the rotating shaft 31 extends, which will be described later. Hereinafter, the vertical direction may be referred to as the "vertical direction".

The reaction vessel 20 has a bottom portion 21 having a funnel-shaped bottom surface 23 and a straight body portion 25 continuous with the bottom portion 21 . The straight body portion 25 is a vertical wall portion extending in the same direction as the direction in which a rotating shaft 31 described later extends. The inner surface of the straight body portion 25 is a vertical wall surface extending in the same direction as the direction in which the rotating shaft 31 extends from the upper end of the funnel-shaped bottom surface 23 . The straight body portion 25 constitutes a bent portion 28 . The bent portion 28 may be curved when the reaction vessel 20 is viewed from the side. A thermometer 71 (resistance temperature detector) is attached to the side of the straight body portion 25 of the reaction vessel for measuring the temperature inside the zeolite solid phase synthesized inside the reaction vessel 20 and adjusting it to the target temperature. there is The temperature inside the reaction vessel 20 is controlled using a thermometer 71 or the like.

As shown in FIGS. 1 and 2(a), the reaction vessel 20 has a stirring member 30 capable of stirring the internal reservoir. The stirring member 30 includes a rotating shaft 31 positioned in the center of the funnel-shaped bottom surface 23 and extending vertically when the reaction vessel 20 is viewed from above, a first stirring blade 41 attached to the rotating shaft 31, and a rotating shaft 31. and a second impeller 51 mounted above the first impeller 41 on the shaft 31 . As shown in FIG. 1 , the second stirring blade 51 is provided at a position facing the straight body portion 25 in the direction perpendicular to the rotating shaft 31 . Both the first stirring blade 41 and the second stirring blade 51 have blade portions (wing portions 43, 53, 63).

In the example shown in FIGS. 1 and 2(a), the second stirring impeller 51 is a blade portion extending radially outward of a circle centered on the rotating shaft 31, and is positioned below the rotating shaft in the extending direction. It has a lower wing portion 63 and an upper wing portion 53 positioned above. In the example shown in FIGS. 1 and 2( a ), the second stirring blade 51 has an upper blade portion 53 and a lower blade portion 63 . However, for example, only the upper wing portion 53 may be provided without the lower wing portion 63 . Each of the plurality of upper wing portions 53 has a scraper (second wing portion) 47 at the radially outer tip. The scraper 47 has an edge portion 42a that faces the vertically extending wall surface of the straight body portion 25 (hereinafter also referred to as "vertical wall surface") and extends along the vertical wall surface along the extending direction of the vertical wall surface. In the example shown in FIGS. 1 and 2A, the same number of upper wing portions 53 and lower wing portions 63 are present. When the reaction vessel 20 is viewed from above, the radially outward extending directions of the plurality of upper wing portions 53 and the plurality of lower wing portions 63 are aligned with each other. The radially outer end portion of the lower wing portion 63 located below is coupled to the scraper 47 to which the upper wing portion 53 located above is coupled.

As shown in FIG. 1, the rotary shaft 31 is connected to a support 32 of the rotary shaft 31 attached to the lid 24, and the support 32 has a motor (not shown) for driving the rotary shaft 31. ing. The rotating shaft 31 is rotatable about the center of the bottom surface when the reaction vessel 20 is viewed from above by a motor (not shown). By rotating the rotary shaft 31, the first stirring blade 41 and the second stirring blade 51 are driven integrally with the rotary shaft 31, so that the internal storage material of the reaction vessel 20 can be stirred.

In the second step of discharging the zeolite, the first stirring impeller 41 mainly plays the role of peeling off the zeolite adhered to the bottom surface 23 of the reaction vessel 20 and fluidizing it. In the second step, the second stirring blade 51 has the role of stripping off the zeolite solid phase portion formed in the lower portion of the straight body portion 25 of the reaction vessel 20 from the inner surface of the straight body portion 25 and fluidizing it. By stirring the liquid phase above the upper surface of the solid phase, it plays a role of causing a vertical flow together with the first stirring blade 41 . This vertical flow rakes up the zeolite deposited in the lower part of the reaction vessel 20, and also feeds the reaction mother liquor in the upper part of the reaction vessel 20 downward to take it into the lump-like zeolite and promote fluidization. The stirring member 30 is preferably made of stainless steel or the like.

Each blade portion 43 of the first stirring blade 41 has a shape in which at least a part of the surface positioned on the upper surface side of the reaction vessel 20 is inclined with respect to the horizontal plane. For example, the blade portion 43 of the first stirring blade 41 has a plate shape whose upper surface is inclined with respect to the horizontal plane when viewed from a direction orthogonal to the direction in which the rotating shaft extends (hereinafter, the shape is referred to as an “inclined plate shape”). ), or, when viewed from the radially outer side to the inner side in the longitudinal direction, the cross section preferably has a triangular or trapezoidal shape tapered upward. The cross-sectional shape of the blade portion 43 of the first stirring blade 41 is preferably triangular or trapezoidal for the following reasons. That is, in this case, even when the rotating shaft 31 rotates in either the forward or reverse direction when the rotation of the rotating shaft 31 is started, the pressure receiving area of the shear resistance received from the zeolite solid phase is reduced to reduce the torque load of the motor. This is because the zeolite solid phase portion can be efficiently peeled off from the bottom surface 23 of the reaction vessel 20 and crushed. In particular, in the blade portion 43 of the first stirring blade 41, in which the torque load of the motor tends to be large in order to stir the zeolite solid phase generated at the bottom, the shape of the cross section is triangular or trapezoidal. is preferable, and the triangular shape is more preferable. When the shape of the cross section is triangular or trapezoidal, the blade portion 43 of the first stirring blade 41 is triangular or trapezoidal. The trapezoidal shape of the cross section is preferably an isosceles trapezoidal shape.

In the example shown in FIGS. 1 and 2(a), the blade portion 43 of the first stirring blade 41 has an isosceles triangular cross-sectional shape. This isosceles triangle consists of one base and two equilateral sides, and has a shape in which the vertex, which is the intersection of the two equilateral sides, faces upward. When the shape of the cross section is an isosceles triangle, it is preferable that the base angle is acute. In this case, the pressure receiving area of the shear resistance received from the zeolite solid phase can be further reduced and the torque load of the rotating shaft 31 can be further reduced in both forward and reverse rotation when the rotation of the rotating shaft 31 is started. The angle of the base angle of the isosceles triangle shape of the cross section minimizes the shearing force when the stirring member 30 is started to rotate forward or backward after the completion of synthesis, and draws the zeolite solid phase from the bottom surface 23 of the reaction vessel 20. From the viewpoint of efficient crushing after peeling, the angle is preferably 20° or more and 40° or less, more preferably 25° or more and 35° or less.

The first stirring blade 41 has an edge portion 42 extending along the inclined surface 23 a of the reaction vessel 20 . In the example of FIGS. 1 and 2(a), the edge portion 42 corresponds to the bottom surface or the vertex of the bottom angle of the isosceles triangle in the cross section perpendicular to the direction in which the wing portion 43 extends. The edge portion 42 extends linearly along the inclined surface 23a. When the rotating shaft 31 rotates, the first stirring impeller 41 is driven so that its edge 42 rotates along the funnel-shaped bottom surface 23 of the reaction vessel 20 . As a result, the lumped zeolite formed on the bottom surface of the reaction vessel 20 can be effectively loosened and fluidized, and zeolite remaining on the bottom surface 23 of the reaction vessel 20 can be effectively suppressed.

In this embodiment, the inclined surface 23a of the bottom portion 21 of the reaction vessel 20 and the edge portion 42 of the first stirring blade 41 are in a non-contact state. The inventor believes that this configuration has the following effects.
For slurries containing nanoparticles, the viscosity of the slurry is often pseudoplastic, ie, a fluid whose viscosity decreases with increasing shear rate. Furthermore, in the case of a porous material such as zeolite, the behavior of the slurry is even more susceptible to the shear rate because of its large specific surface area. That is, a non-fluidized zeolite slurry, a so-called zeolite cake, has a very high viscosity and is not easily fluidized. For example, a plurality of beta zeolites prepared by adding seed crystals to a reaction mixture containing no OSDA were separated from the reaction mixture and the relationship between shear rate and viscosity was analyzed using a 25 mm diameter parallel plate MCR-501 manufactured by Anton Paar. , and after stirring for 1 minute at a steady flow of 100/s with a gap of 1 mm, the measured graph is shown in FIG. The plot of ▲●■ is the viscosity of the slurry in which 1 volume of zeolite is added to 1 volume of water, and the plot of △○□ is the viscosity of the slurry in which 3 volumes of water are added to 1 volume of the same zeolite. is. The beta-type zeolite used for the measurement is the slurry taken out from the reaction vessel after completion of the reaction in Comparative Example 1 described later.
As shown in FIG. 3, regardless of whether the amount of zeolite in the slurry is large or small, when the zeolite shear rate is close to zero, the shear stress is extremely large and it is extremely difficult to impart fluidity. However, if very little shear force can be applied, the viscosity drops sharply, allowing agitation and fluid transport. Also, it can be seen that although the viscosity is low when the proportion of water in the slurry is high, the viscosity increases ten times or more when the proportion of zeolite is high.
Therefore, the present inventors found that the shear rate can be maximized by installing the edge portion 42 of the first stirring blade 41 that gives the shear rate near the inner wall of the reaction vessel 20, and that the resulting fluidized zeolite was diluted by the reaction mixture solution, and the entire zeolite slurry was fluidized.

The ability to control the reaction time according to the present invention is important in the production of zeolites.
As described above, the reaction mixture, which is the raw material for producing zeolite, contains a solid-phase aluminosilicate gel and a liquid-phase alkaline aqueous solution. For example, when the reaction mixture described in Patent Document 1 is heated without adding seed crystals, mordenite zeolite, which is a stable phase, precipitates. A zeolite is obtained. When unstable-phase zeolite is produced without using OSDA, the amount of unstable-phase zeolite formed increases with reaction time, but the degree of crystallinity increases at an accelerated rate as the reaction time increases. When the reaction time reaches the maximum crystallinity of the unstable phase zeolite, the stable phase zeolite gradually increases. If the reaction time is too short, the crystallinity of the unstable phase zeolite will be low, and if the reaction time is too long, the amount of the stable phase zeolite will increase and at the same time the crystallinity of the unstable phase zeolite will decrease, so the reaction time can be accurately controlled. There is a need to.

The closer the edge portion 42 of the first stirring blade 41 is to the inner wall of the reaction vessel 20, the greater the shear rate that can be imparted. However, if they are too close to each other, the amount of the slurry with reduced viscosity decreases, and the ratio of the amount of slurry with reduced viscosity for loosening the entire zeolite cake is reduced. From the above point of view, the interval W (see FIG. 1) between the inclined surface 23a of the bottom portion 21 of the reaction vessel 20 and the edge portion 42 of the first stirring blade 41 is the first The ratio (W / L1) to the length L1 (see FIG. 4 (b)) of the edge portion of the stirring blade 41 is preferably 0.8% or more and 5.0% or less, and 1.5% or more It is more preferably 3.5% or less.

In the example shown in FIGS. 1 and 2(a), the first stirring blade 41 is provided with a plurality of blades of the same shape, preferably 1 to 6 blades, particularly preferably 2 to 5 blades.

The second stirring blade 51 has a shape in which at least a part of the surface located on the upper surface side of the reaction vessel 20 is inclined with respect to the horizontal plane when viewed from the direction perpendicular to the direction in which the rotating shaft extends. wings. For example, when the blade portion of the second stirring blade 51 is viewed from the radially outer side toward the inner side in the direction in which it extends, the upper surface of the second stirring blade 51 has a plate-like shape (slanted plate-like shape) inclined with respect to the horizontal plane. Alternatively, it is preferable that the cross section perpendicular to the extending direction of the wings has a triangular or trapezoidal shape tapered upward. It is preferable that the shape of the cross section of the second stirring blade 51 is triangular or trapezoidal for the same reason as explained for the first stirring blade 41 described above. For example, of the upper blade portion 53 and the lower blade portion 63 of the second stirring impeller 51, the lower blade portion 63 has a triangular or trapezoidal shape that narrows upward in cross section, and the upper blade portion 53 may have a triangular or trapezoidal shape tapered downward in cross section.

In the example shown in FIGS. 1 and 2(a), each of the upper blade portion 53 and the lower blade portion 63 of the second stirring blade 51 has an inclined plate shape. Each of the upper wing portion 53 and the lower wing portion 63 has a plate shape with a substantially rectangular cross section perpendicular to the extending direction thereof. Accordingly, each of the upper wing portion 53 and the lower wing portion 63 has a shape in which at least a part of the surface located on the lower surface side of the reaction vessel 20 is also inclined with respect to the horizontal plane. When the upper blade portion 53 and the lower blade portion 63 of the second stirring blade 51 are inclined plates, they may be inclined in the same direction or in opposite directions.
By using the triangular column-shaped first stirring blade 41 and the inclined plate-shaped second stirring blade 51, a vertical flow is generated in the reaction vessel 20 without using a baffle plate. It is preferable because it can be Installation of a baffle plate in the reaction vessel 20 is not preferable from the standpoint of cake adhesion and cake peeling blind spots.
By using a triangular prism-shaped one as the first stirring blade 41 and using an inclined plate-shaped one as the second stirring blade 51, it is possible to prevent the phenomenon that zeolite crystals are accumulated on the upper surface of the stirring blade and adhere firmly, and impurities are removed. can effectively reduce the possibility of causing the generation of

From the viewpoint of enhancing the effect of fluidizing zeolite and reducing the power of the stirrer, the inclination angle A (see FIG. 2(c)) of the blade portion 43 of the first stirring blade 41 with respect to the horizontal plane should be more than 0° to 60°. Preferably, 5° to 45° is more preferred. From the viewpoint of effectively causing a flow in the vertical direction and reducing the stirring power, the inclination angle B (see FIG. 2(b)) of the upper blade portion 53 of the second stirring blade 51 with respect to the horizontal plane is more than 0° to 60°. is preferred, and 5° to 50° is more preferred.
As shown in FIGS. 2B and 2C, the inclination angle A formed by the horizontal plane of the blade portion 43 and the inclination angle B formed by the horizontal plane of the upper blade portion 53 are determined by is an acute angle of inclination of the upper surface of the inclined plate with respect to the horizontal line Lx in the cross section orthogonal to the extending direction of the wing portion, and the cross section orthogonal to the extending direction of the wing portion 43 or the upper wing portion 53 is a triangle. , it is the maximum acute angle formed by any side of the triangle in the cross section and the horizontal line Lx, and if the cross section of the cross section perpendicular to the extending direction of the wing is trapezoidal, the trapezoidal angle in that cross section This is the maximum acute angle formed by any side and the horizontal line Lx. (This also applies to the inclination angle C of the lower blade portion 63, which will be described later).

The second stirring blade 51 is provided with a plurality of blades of the same shape. The number of the upper wing portions 53 and the lower wing portions 63 is preferably 1 to 6, particularly preferably 2 to 5, respectively. The number of blades of the first stirring blade 41 and the upper blade portion 53 and/or the lower blade portion 63 of the second stirring blade 51 may be the same or different.

In this embodiment, the plurality of first stirring blades 41, the plurality of upper stage blade portions 53, and the plurality of lower stage blade portions 63 extend in the same direction from the rotating shaft 31 when the reaction vessel 20 is viewed from above. I am doing it. In this case, there is an advantage in that a large opening area can be ensured for accessing the interior through a mirror portion manhole (not shown) provided in the lid 24, such as for collecting a sample. However, the wing portion 43, the upper wing portion 53, and the lower wing portion 63 may extend in different directions from the rotating shaft 31 in the plan view.

As in the example of FIG. 2( a ), the first stirring blade 41 , the upper blade portion 53 and the lower blade portion 63 , which are three stages of stirring blades, stir the deposited zeolite and the liquid phase above it. By doing so, the fluidization effect of the zeolite can be further enhanced. In particular, as shown in FIG. 4A, which will be described later, the first stirring blade 41 serves to separate the zeolite 1 from the bottom of the reaction vessel 20, and the lower blade 63 serves to directly loosen the zeolite 1 above the bottom of the reaction vessel. , the upper wing 53 plays a role of generating a vertical flow of the zeolite in the upper part of the portion 2 consisting of the liquid phase, and the zeolite can be effectively fluidized.

In order to increase the effect of fluidizing the zeolite and the production efficiency, the inclination angle C of the inclined surface of the lower blade portion 63 with respect to the horizontal plane (see FIG. 2(b)) is preferably more than 0° to 60°, and is preferably 5° to 50°. is more preferred.

As shown in FIGS. 1 and 2(a), in the present embodiment, the second stirring impeller 51 further includes a second impeller 47 connected to the outer ends of the impellers 53 and 63. The second wing portion 47 has an edge portion 42a extending along the vertical wall surface of the straight body portion 25 and along the direction in which the vertical wall surface extends. can be effectively removed. In the example shown in FIGS. 1 and 2( a ), the second stirring blade 51 is a plate-like scraper arranged to extend vertically along the vertical wall surface of the straight body portion 25 . An edge portion 42a is provided as the radially outer edge portion.

The width of the gap between the edge portion 42a and the straight body portion 25 can be the same as the width W of the gap between the edge portion 42 and the inclined surface 23a.
Of the total length L2 in the vertical direction (see FIG. 1) in the reaction vessel 20, the edge portion of one of the stirring blades and the inner wall of the reaction vessel 20 are close to each other so as to have a gap within the range described as the width W. The ratio (L3/L2) of the length L3 of the portion in which it is present is preferably 5% or more and 70% or less, and more preferably 35% or more and 65% or less. In FIG. 1, L3 is the sum of L3a and L3b.

From the viewpoint of effectively fluidizing the zeolite adhering to the lower part of the straight body part 25 of the reaction vessel 20, the second wing part (scraper) 47 is arranged around the rotating shaft 31 when the reaction vessel 20 is viewed from above. It is preferably inclined with respect to a straight line connecting the center of the circle and the second wing portion 47 . In that case, the inclination angle (acute angle) of the second wing portion 47 with respect to the straight line is preferably less than 90° and 30° or more, for example. In the example shown in FIGS. 1 and 2(a), the second blade portions 47 of the plurality of second stirring blades 51 are inclined in the same direction with respect to the straight line of the second blade portions 47. there is In the present embodiment, the second wing portion 47 is a vertical plate portion and has a plate-like shape. Although it is similarly inclined at an inclination angle within the above range, it is not limited to this.

A method for producing zeolite according to the present embodiment using the reaction vessel 20 described above will be described.
This production method is a zeolite production method in which seed crystals are added to a reaction mixture containing a silica source, an alumina source, an alkali source, and water, and not containing an organic structure-directing agent, followed by heating,
a first step of heating the reaction mixture and seed crystals in a closed reaction vessel 20 and allowing them to react in a stationary state;
a second step of discharging the zeolite mass produced by the reaction out of the reaction vessel 20,
In the second step, the rotating shaft 31 is rotated to fluidize the zeolite by the first stirring blade 41 and the second stirring blade 51 , and the fluidized zeolite is discharged from the discharge port 22 . In the second step, the rotation shaft 31 is rotated at the same time as the temperature drop is started, and the zeolite is fluidized by the first stirring blade 41 and the second stirring blade 51 to quickly cool the contents while increasing the cooling efficiency. It is preferable from the point of being able to effectively suppress the generation of impurities.

Silica sources include silica itself and silicon-containing compounds capable of forming silicate ions in water. Specific examples include wet-process silica, dry-process silica, colloidal silica, sodium silicate, and aluminosilicate gel. These silica sources can be used alone or in combination of two or more.

As an alumina source, for example, a water-soluble aluminum-containing compound can be used. Specific examples include sodium aluminate, aluminum nitrate, and aluminum sulfate. Aluminum hydroxide is also a suitable source of alumina. Aluminosilicate gel can also be used as an alumina source. These alumina sources can be used alone or in combination of two or more.

As an alkali source, for example, sodium hydroxide can be used. When sodium silicate is used as the silica source or sodium aluminate is used as the alumina source, sodium, which is an alkali metal component contained therein, is simultaneously regarded as NaOH and is also an alkali component. Therefore, the Na ₂ O mentioned above is calculated as the sum of all alkaline components in the reaction mixture.

This production method uses the stirring member 30 not only as a fluidizing member for loosening and fluidizing the zeolite crystal cake produced, but also as a stirring member for mixing the reaction mixture and raising the temperature of the contents. Also, it is preferably used as a member for promoting heat transfer when lowering the temperature. By configuring in this way, zeolite can be produced by a relatively simple mechanism by a static crystallization method without using OSDA.

Prior to the reaction, the outlet 22 is closed. The reaction mixture and seed crystals are premixed or mixed in the reaction vessel 20 and filled in the reaction vessel 20 . Depending on the ratio of the solid phase to the liquid phase, in many cases, the slurry and seed crystals will sediment without agitation and separate into a clear layer of an alkaline aqueous solution at the top. Therefore, it is preferable that the reaction mixture and the seed crystals are well mixed macroscopically, and more uniformly mixed at a temperature lower than the reaction temperature after entering the reactor. From this point of view, it is preferable to rotate the rotating shaft 31 and stir the reaction mixture and the seed crystals with the first stirring blade 41 and the second stirring blade 51 when the reaction temperature is not reached. While stirring is continued, steam or a heat medium is circulated through the jacket 26 installed outside the reaction vessel 20 to start raising the temperature. The reaction temperature is, for example, 100 to 200°C, preferably 120 to 180°C.

Stirring is stopped before the temperature is raised to the reaction temperature, and the reaction is started in a still state. The solid phase consisting of slurry and seed crystals gradually settles and gathers in the lower part, and the upper part of the apparatus becomes an alkaline aqueous solution in which aluminosilicate is slightly dissolved. As shown in FIG. 4( a ), after the reaction, for example, the upper wing portion 53 of the second stirring blade 51 located above (when the amount of content charged is small, the upper wing portion 53 and the lower wing portion 63 ) is positioned in the clarification portion 2 above the deposition portion 1 of the produced massive zeolite. It is preferable in terms of better exhibiting the effect of promoting conversion. In addition, the code|symbol 3 of Fig.4 (a) is a water surface.

After the reaction, the temperature in the apparatus is lowered by stopping the steam or heat medium in the jacket 26 or by circulating a low-temperature heat medium. Indirect cooling of the contents of the reaction vessel 20 is initiated by stopping the steam or heat transfer medium or by circulating a low temperature heat transfer medium. It is preferable to start a motor (not shown) for rotationally driving the rotating shaft 31 at the same time as the indirect cooling is started, because rapid cooling from the reaction temperature can reduce the cause of impurity generation.
In the manufacturing apparatus 10 described above, the zeolite crystal cake layer adhering to the inner wall of the reaction vessel 20 can be effectively peeled off by applying forward and reverse torque several times at a low speed. Further, the rotary shaft 31 is rotated, and the internal reserves are stirred and fluidized by the first stirring blade 41 and the second stirring blade 51 so as to generate an upward flow in the reaction vessel 20 . After that, the discharge port 22 at the bottom of the reaction vessel 20 is opened, and the zeolite crystals are taken out from the reaction vessel 20 .

Immediately after the discharge port 22 is opened, the zeolite pulverized by the first stirring blade 41 and the second stirring blade 51 into a sludge has a higher specific gravity than the liquid phase inside the reaction vessel 20, so the discharge port 20 is closed. It accumulates in the vicinity, causes bridging, and blocks the discharge port 22, so that the internal slurry may not be discharged smoothly.
In this case, in order to smoothly discharge the internal slurry, as shown in FIGS. It is preferable to install a small-diameter introduction pipe 94 for introducing the pressurized dry air between the second discharge valve 93 attached to the other end.

According to the above mechanism, while the first exhaust valve 90 is closed, the second exhaust valve 93 is closed to introduce the dry air pressurized from the introduction pipe 94, and between the first exhaust valve 90 and the second exhaust valve 93 Dry air is introduced and pressure is accumulated. Next, the introduction of dry air into the elbow pipe 92 is temporarily stopped, and the first discharge valve is opened at once to blow the dry air pressure-accumulated inside the elbow pipe 92 into the reaction vessel 20 . By performing this operation several times, the solidified zeolite at the bottom of the reaction vessel can be dispersed, and the bridging caused by the sludge-like zeolite blocking the vicinity of the discharge port 22 is eliminated, and the slurry inside the reaction vessel 20 becomes smooth and smooth. It can be ejected vigorously. By this operation, the time for discharging the slurry to the outside is extremely shortened. The elbow pipe 90 and the introduction pipe 94 correspond to air pipes in preferred embodiments of the present invention.

The state of the content after synthesis in the reaction vessel 20 is roughly divided into a zeolite solid phase portion and a liquid phase portion above it. When synthesized according to the procedure of (2) Synthesis of OSDA-free beta zeolite in Comparative Example 1 below, the volume (Vs) of the zeolite solid phase portion in the reaction vessel is the volume (VT) of the content after synthesis. The ratio is preferably 20% or more and 60% or less, more preferably 30% or more and 40% or less. By setting this range, it is possible to suppress the increase in torque for rotating the stirring member 30 due to hardening due to too much solid phase, and increase the production efficiency. The composition of the reaction mixture may be adjusted to achieve the above volume ratio.

Considering the ratio of the zeolite solid phase to the entire contents, the first stirring blade 41 has the role of peeling off the zeolite solid phase from the bottom of the reaction vessel 20. Therefore, the funnel-shaped bottom 21 of the reaction vessel 20 It is preferable that the height position to be installed above is as follows. Specifically, the height position of the first stirring blade 41 is set at a position where the volume of the reaction vessel below the height is 5% or more and 115% or less of the total volume of the zeolite solid phase after the reaction. It is more preferable to install it within the range of 20% or more and 50% or less. The height position of the first stirring blade 41 refers to the upper end of the height position where the blade portion 43 is attached to the rotating shaft.

In addition, the lower blade portion 63 of the stirring blade 51 is installed in the straight body portion 25 of the reaction vessel 20 in order to separate the zeolite solid phase portion from the straight body surface of the reaction vessel 20, and the height position is the position The volume of the following reaction vessel is preferably set within a range of 38% or more and 100% or less of the total volume of the zeolite solid phase after the reaction, preferably 70% or more and 95% or less. more preferred. The height position of the lower wing portion 63 refers to the height position at which the lower wing portion 63 is attached to the rotating shaft.

In addition, the upper blade part 53 of the second stirring blade is installed in the straight body part of the reaction vessel 20, and the volume of the reaction vessel below the height position is the zeolite solid phase part in the reaction vessel. It is preferably installed at a position that accounts for 55% or more and 155% or less, more preferably 100% or more and 120% or less, of the total volume (VL) of the solution phase portion of the mother liquor formed immediately above. The height position of the upper wing portion 53 refers to the height position at which the upper wing portion 53 is attached to the rotating shaft.

Further, in the present embodiment, a thermometer 71 is arranged at a height position where the volume from the bottom is 20% or more and 30% or less of the total volume of the reaction mixture containing portion in the reaction vessel, and the temperature is measured. Preferably, the measured temperature is used to control the zeolite synthesis temperature. This is because zeolite production is accompanied by endothermic heat and heat associated with dissolution and crystallization, and it is thought that the reaction temperature can be controlled more accurately by positioning the thermometer at a position where the temperature of the solid phase during the stationary reaction can be measured. be. Also, if the position of the thermometer is too low, it interferes with stirring at the bottom. From this point of view, in the present embodiment, the first stirring blade 41 and the second stirring blade 51 are configured so as not to be connected at a portion other than the rotating shaft, and the first stirring blade 41 and the second stirring blade 51 It is placed at a height position between

As described above, the zeolite production method that does not use OSDA is limited in that the reaction mixture is a slurry solid, the product immediately after the reaction is in the form of lumps, and the zeolite raw material cannot be mixed during the reaction. be. However, according to this production method, the zeolite yield can be improved with a simple mechanism, and the zeolite removal operation in the apparatus can be greatly improved.

Any zeolite may be used as long as it is obtained by a zeolite production method in which a seed crystal is added to a reaction mixture containing no organic structure-directing agent and then heated, and the crystal types include beta type, chabazite type, and MWW type. , MSE type, MTW type, MEL type and PAU type, preferably beta type. The reason why the beta type is preferred is as follows. As described above, when a reaction mixture containing an aluminosilicate gel (solid phase) and an aqueous alkali solution (liquid phase) is heated without adding seed crystals, mordenite-type zeolite precipitates. Beta zeolite is obtained by adding seed crystals of beta zeolite and heating in a stationary state. On the other hand, when seed crystals of beta-type zeolite are added to the reaction mixture and the mixture is reacted at the reaction temperature, mordenite-type zeolite is often formed if a certain amount of stirring is given. The reason for this physical phenomenon has not been elucidated, but it is speculated that even if beta-type zeolite precipitates, it rearranges to thermodynamically more stable mordenite-type zeolite when physical energy such as stirring is applied. . As described above, beta-type zeolite tends to generate impurities due to stirring during the reaction, especially when it is produced by mixing seed crystals with a reaction mixture to which OSDA is not added and heating, and production by static crystallization is the required zeolite. Application of the present invention to such beta-type zeolite is preferable in that it has great industrial significance.

As a method for synthesizing the OSDA-free beta zeolite, for example, the method described in International Publication No. 2011/013560 can be adopted. Also, the method described in Chinese Patent Application Publication No. 101249968 can be adopted. Furthermore, Chemistry of Materials, Vol. 20, No. 14, p. 4533-4535 (2008) can also be employed.

An example of a method for synthesizing OSDA-free beta zeolite is as follows.
(i) mixing a silica source, an alumina source, an alkali source, and water so as to form a reaction mixture having a composition represented by the molar ratios shown below;
Si/Al molar ratio is 4 or more and 100 or less, especially 5 or more and 100 or less OH/Si molar ratio is 0.35 or more and 0.8 or less, especially 0.37 or more and 0.7 or less H ₂ O/Si molar ratio is 10 or more 50 or less, especially 12 or more and 25 or less (ii) Beta zeolite containing no organic compound, having a SiO ₂ /Al ₂ O ₃ molar ratio of 8 to 30 and an average particle size of 150 nm or more, particularly 150 to 1000 nm as a seed crystal, which is added to the reaction mixture at a rate of 0.1 to 20% by mass with respect to the silica component in the reaction mixture,
(iii) Hermetically heating the reaction mixture to which the seed crystals have been added at 100-200°C, especially 120-180°C. The average particle size refers to the particle diameter of crystals with the highest frequency in observation with a scanning electron microscope.

One means of obtaining a reaction mixture within the above range is to use an aluminosilicate gel as the reaction mixture. Aluminosilicate gels can be used as sources of silica and alumina. When an aluminosilicate gel is used as the reaction mixture, it is easier to maintain a uniform composition than a mixture of silica powder and sodium aluminate, even if the reaction mixture is held without stirring in a large reactor. There is an advantage. A specific method includes, for example, a method of mixing an aluminosilicate gel, sodium hydroxide and water to obtain a reaction mixture. The mixing ratio in this case may satisfy the preferable molar ratio of (i) above. The aluminosilicate gel preferably accounts for 70% by mass or more of the silica source and 70% by mass or more of the alumina source, and may account for 80% by mass or more of the silica source and 80% by mass or more of the alumina source. More preferably, all silica sources and alumina sources may be aluminosilicate gels.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above aspect. For example, the manufacturing apparatus 10 of the present invention may use a stirring member 30' shown in FIG. 5 instead of the stirring member 30 shown in FIG. 2(a).

In the stirring member 30', the first stirring impeller 41 has an inclined plate shape. In addition, only the lower blade portion 63 in the second stirring blade 51 has a scraper 67 having an edge portion extending along the wall surface of the straight body portion, and the upper blade portion 53 and the lower blade portion 63 are not connected. . Otherwise, stirring member 30 ′ is similar to stirring member 30 .

(Example 1)
(1) Synthesis of Seed Crystal Using tetraethylammonium hydroxide as an organic SDA, sodium aluminate as an alumina source, and finely powdered silica (Mizukasil P707) as a silica source, a conventionally known method was used, stirring and heating at 165° C. for 96 hours. to synthesize beta zeolite having a SiO ₂ /Al ₂ O ₃ molar ratio of 24.0. This was calcined at 550° C. for 10 hours in an electric furnace while circulating air to produce a crystal containing no organic matter. Observation of this crystal with a scanning electron microscope revealed that the average particle size was 280 nm. Crystals of beta zeolite containing no organic matter were used as seed crystals.
(2) Production of Reaction Mixture Into 820 kg of industrial water, 20 kg of the above seed crystals were stirred and mixed. 1920 kg of aluminosilicate gel (= “powder product precursor”, water content 70.1% by mass, Si/Al molar ratio=8.0) was added to the mixed solution while stirring and mixing. Further, 320 kg of 30% by mass sodium hydroxide was added and mixed with stirring to obtain a reaction mixture (OH/Si molar ratio: 0.5, H ₂ O/Si molar ratio: 16.5).
(3) Synthesis of OSDA-free beta-type zeolite Production apparatus 10 shown in FIG. .5%, L3/L2=53.9%, internal space volume of reaction vessel 20=3.5 m ³ ) was used.
The above reaction mixture was placed in a stainless steel reactor 20 and heated at 150° C. for 47 hours under autogenous pressure without aging.
The height position of the thermometer and the height position of each of the wings 43, 53, and 63 were within the most preferable range of the ranges described above for the volume of the reaction vessel below the height.
After the reaction time had passed, the reaction vessel 20 was switched from heating to cooling, and then torque was applied for forward rotation and reverse rotation several times at low speed as needed. After that, the rotary shaft 31 is rotated clockwise in plan view, and the upper blade portion 53 of the first stirring blade 41, the second stirring blade 51, and the second stirring blade 51 are caused to generate an upward flow in the reaction vessel 20 The internal reservoir was stirred by the lower blade portion 63 of the stirring blade 51 to fluidize the zeolite. Except for this point, it was the same as Comparative Example 1. After the zeolite was discharged, almost no zeolite adhered to the inner wall surface of the reaction vessel 20 was observed.
Similar results were obtained when the amount of each component was reduced to 1/4 and a similar production apparatus with a capacity of 500 liters was used.

(Comparative example 1)
A reaction vessel 120 made of stainless steel and having an elliptical bottom shown in FIG. 6 was used instead of the reaction apparatus shown in FIG. Also, the amount of each component was 1/4, and the capacity of the reaction vessel 120 was 500 liters. The reaction was carried out in the same manner as in Example 1 except for this point. A stirring member shown in FIG. 7(a) was used for stirring before the reaction, but stirring was not performed after the reaction was completed.
After the reaction was completed, the valve 121 blocking the discharge port 122 at the bottom of the reaction vessel 120 was opened, but the produced zeolite was not discharged. After cooling, the lid portion 123 was opened, and the zeolite in the reaction vessel 120 was stirred with a stirring rod to be fluidized and discharged from the discharge port 122 . After that, when the inside of the reaction vessel 120 was observed, it was confirmed that zeolite was deposited on the bottom and adhered to the inner wall of the reaction vessel 120 . An attempt was made to remove the zeolite adhered to the inner wall of the reaction vessel 120 with a high-pressure washing device, but it could hardly be removed. Finally, it was cleaned by adding an aqueous solution of caustic soda with a concentration of 1 to 10% by mass and stirring at 80° C. for 12 hours.

(Comparative example 2)
After the reaction was completed, the zeolite was stirred by the stirring member shown in FIG. 7A after cooling without opening the valve 121 . The rest was the same as in Comparative Example 1. However, when the stirring member shown in FIG. 7(a) was used, the zeolite could not be fluidized.

(Comparative Example 3)
The stirring member was changed from that shown in FIG. 7(a) to that shown in FIG. 7(b). The rest was the same as in Comparative Example 2. As a result, the same results as in Comparative Example 2 were obtained.

10 Zeolite manufacturing equipment
20 reaction vessel
21 bottom
23 Bottom
23a Inclined surface
30 stirring member
31 rotating shaft
32 support
41 first stirring blade
42 edges
51 second stirring blade

Claims (15)

A zeolite raw material containing a reaction mixture containing a silica source, an alumina source, an alkali source, water, and no organic structure-directing agent, and seed crystals is heated in a closed reaction vessel and allowed to react in a stationary state. a first step;
A method for producing zeolite, comprising:
The reaction vessel has an outlet for discharging the zeolite at the bottom, and the bottom is formed into a funnel shape having a downwardly inclined surface toward the outlet,
The reaction vessel has a stirring member,
The stirring member includes a rotating shaft that is positioned at the center of the funnel-shaped bottom surface and extends vertically when the reaction vessel is viewed from above, and a rotating shaft that is attached to the rotating shaft and extends along the inclined surface of the reaction vessel. A first impeller having an edge and a second impeller attached to the top of the first impeller on the rotating shaft,
The inclined surface of the bottom of the reaction vessel and the edge of the first stirring blade are in a non-contact state,
In the second step, the rotating shaft is rotated to fluidize the zeolite with the first stirring blade and the second stirring blade, and the fluidized zeolite is discharged from the discharge port. In a plan view of the reaction vessel, each of the first stirring blade and the second stirring blade has a blade portion extending radially outward of a circle centered on the rotation axis,
2. According to claim 1, wherein when viewed from a direction perpendicular to the direction in which the rotating shaft extends, each of the blade portions of the first stirring blade and the second stirring blade has a shape having an upper surface inclined with respect to a horizontal plane. A method for producing the described zeolite. 3. The method for producing zeolite according to claim 2, wherein the blade portion of the first stirring blade has a triangular shape with a cross section perpendicular to the direction in which it extends. The reaction vessel has a vertical wall surface extending in the same direction as the direction in which the rotating shaft extends from the upper end of the funnel-shaped bottom surface,
The second stirring impeller further comprises a second impeller connected to the outer end of the impeller, the second impeller having an end extending along the vertical wall surface and along the direction in which the vertical wall surface extends. The method for producing a zeolite according to claim 2 or 3, which has edges. The blade portion of the second stirring blade according to any one of claims 2 to 4, wherein the blade portion has a lower blade portion positioned on the lower side in the direction in which the rotating shaft extends, and an upper blade portion positioned on the upper side. A method for producing the described zeolite. The method for producing zeolite according to any one of claims 1 to 5, wherein the stirring member has a structure in which the first stirring blade and the second stirring blade are not connected except at the rotating shaft. The method for producing zeolite according to any one of claims 1 to 6, wherein the inclined surface of the bottom has an angle of more than 42° with a horizontal plane when the reaction vessel is viewed from the side. In the first step, after heating the reaction mixture and the seed crystals while stirring them with the first stirring blade and the second stirring blade, the stirring is stopped, and then the reaction mixture and the seed crystals are allowed to stand still under heating. The zeolite according to any one of claims 1 to 7, wherein the crystals are reacted, and after the reaction, the zeolite is fluidized by the first stirring blade and the second stirring blade in the second step at the same time as the temperature decrease is started. manufacturing method. 9. The method according to any one of claims 1 to 8, wherein the discharge port has an air pipe for introducing air, and the zeolite solidified at the bottom of the reaction vessel is dispersed by introducing air from the air pipe when the zeolite is discharged. 2. A method for producing a zeolite according to item 1. A temperature measuring resistor is placed at a height position where the volume from the bottom is 20% or more and 30% or less of the total volume of the reaction mixture containing portion in the reaction vessel, and the temperature is measured, and the measured temperature is used. The method for producing zeolite according to any one of claims 1 to 9, wherein the zeolite synthesis temperature is controlled. Any one of claims 1 to 10, wherein the zeolite is produced so that the solid phase is deposited to a height position where the volume from the bottom is 30% or more and 40% or less of the total volume of the reaction mixture accommodating portion in the reaction vessel. 2. A method for producing zeolite according to claim 1. The method for producing zeolite according to any one of claims 1 to 11, wherein the zeolite is beta zeolite. The composition of the reaction mixture is
Si/Al molar ratio is 4 or more and 100 or less,
OH/Si molar ratio is 0.35 or more and 0.8 or less,
The method for producing zeolite according to claim 12, wherein the _H2O /Si molar ratio is 10 or more and 50 or less. The method for producing a zeolite according to any one of claims 1 to 13, wherein an aluminosilicate gel is used as the reaction mixture. A production apparatus for producing zeolite without using an organic structure-directing agent,
It has a reaction vessel capable of heating a zeolite raw material in a sealed state, and a stirring member that can be accommodated in the reaction vessel,
The reaction vessel has a discharge port for discharging the fluidized zeolite at the bottom, and the bottom surface of the bottom is formed in a funnel shape having an inclined surface inclined toward the discharge port,
The stirring member includes a rotating shaft positioned at the center of the funnel-shaped bottom surface when viewed from above and extending in the vertical direction, and an edge attached to the rotating shaft and extending along the inclined surface of the reaction vessel. and a second stirring blade attached to the upper part of the first stirring blade on the rotating shaft, the inclined surface at the bottom of the reaction vessel, and the first The manufacturing apparatus, which is in a non-contact state with the edge portion of the stirring blade.

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