JP2917080B2 - Method and apparatus for continuous production of poorly water-soluble salts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously producing a hardly water-soluble salt having a uniform particle size, which is suitable for extender pigments, cosmetics, photographic emulsions, electronic materials, additives and the like.
The present invention relates to an apparatus for continuously mixing and reacting at least two kinds of fluids.

[0002]

2. Description of the Related Art In a reaction for producing a poorly water-soluble salt, the reaction rate is extremely high. Therefore, it is necessary to quickly and uniformly mix different kinds of fluids as raw materials to obtain a product of uniform quality. Is a necessary condition. For example, when two or more kinds of fluids are mixed and reacted to produce a product such as barium sulfate as an extender, the operation is performed continuously,
In order to obtain a uniform and excellent quality product, it is necessary to pay attention to the following points.

(1) After mixing different kinds of fluids which mix and react with each other, the mixed fluid is quickly and uniformly mixed.
This is because, if the mixing becomes partially non-uniform, the reaction speed and the like in each part differ, and a product of uniform quality cannot be obtained. (2) To narrow the residence time distribution in the device. When the residence time distribution in the device becomes wider, the particle growth rate differs,
That is, particles having different shapes and sizes are formed, and the quality of the product discharged from the apparatus varies, resulting in a significant loss of the value of the product. (3) To shorten the residence time in the device. When conducting a continuous manufacturing process industrially, the length of the unstable transient state at the start and stop of the apparatus, which is often a problem, is often due to the length of the residence time in the apparatus, and the residence time Is longer, this transient state becomes longer, not only deteriorating the yield of products, but also uneconomical when producing a wide variety of products using the same equipment. (4) No drive unit or stirring unit is provided in the apparatus. If there is a driving unit or a stirring unit, there is a possibility that the crystal grains of the product are damaged and the quality is impaired. In addition, there is a possibility that the product may adhere to cause an abnormal reaction. Further, cleaning of the device becomes difficult.

Conventionally, in the reaction of a water-insoluble salt having a very high reaction rate with the above-mentioned points to be considered, when a fluid as a raw material is continuously mixed and reacted, (a) a pipeline homomixer ( A device for mixing and reacting by installing a stirrer in a pipe line as in the case of Tokushu Kika Kogyo Co., Ltd., and (b) having multi-stage stirring blades in the vertical direction and providing partitions above and below the stirring blades. A vertical cylindrical stirrer that prevents back mixing by a stirring blade, (c) a draft tube stirrer that is provided with a draft tube and that prevents back mixing, or (d) an orifice that is provided with a perforated plate shelf in a tube. A tower type device was used.

However, regarding (d), the importance of keeping the residence time distribution in the apparatus narrow (attention (2)) is so important that the degree of mixing is low and there is a problem at attention (1). On the other hand, when the devices (a), (b), and (c) are used, mixing of the raw material fluids can be performed quickly, but a driving unit,
Since the stirring section is provided in the apparatus, there was a problem in the point (4) to be noted. Further, regarding (b) and (c), there was a problem in the point (2) to be noted because the reactor was not a tube type but a tank type.

As a means for solving the above problems, Japanese Patent Publication No. Sho 52-31582 discloses a continuous mixing reactor. Although this device mixes different fluids quickly and has a small residence time distribution, it is excellent as a mixing reactor,
Since the apparatus is complicated and has a stirring section in the apparatus, there is a problem in the destruction and adhesion of the product by the stirring section and an abnormal reaction due to the adhesion (note (4)). Further, cleaning of the apparatus cannot be easily performed, and it is difficult to switch the production type, which is uneconomical.

[0007] JP-B-54-22200 and JP-B-62-34688 disclose continuous production methods of poorly water-soluble salts. In Japanese Patent Publication No. 54-22200, the reaction raw material is a liquid-gas, and the reaction is controlled in two stages. This reaction is based on the fact that the rate at which the raw material gas dissolves in the liquid is lower than the rate at which the poorly water-soluble salt is generated, and is being developed into a continuous production method. There are two tank type reactors, and the cost of the apparatus is high.

In Japanese Patent Publication No. 34688/1987, since the starting fluid is supplied in the presence of a reaction product because of a semi-batch reaction method, the residence time distribution is wide, that is, a point (2) to be noted. And the quality of the product discharged from the apparatus varies, resulting in a significant loss of product value. Therefore, in the case of a process for continuously producing a product of a poorly water-soluble salt that requires uniform quality, any of these conventional apparatuses is unsuitable,
Eventually, these processes could not be continuous and had to rely on batch processes.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve such problems. That is, an object of the present invention is a poorly water-soluble salt having a very fast reaction rate.
In the continuous production of barium sulfate , the residence time distribution of the fluid in the device can be kept extremely narrow, and various fluids can be quickly and uniformly distributed even though there is no stirrer / drive in the reactor. To provide a continuous reactor capable of promptly discharging the reaction product to the outside of the reactor, and to provide a continuous production method of barium sulfate having a uniform particle size and good quality. It is in.

[0010]

Means for Solving the Problems Under such circumstances, the present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, two or more kinds of raw materials were reacted to form sulfuric acid which is a poorly water-soluble salt.
In a method for continuously producing barium , at least two kinds of raw materials are continuously supplied to a tubular reactor continuously and reacted, and a reaction product ( barium sulfate and by-products) is further produced. A continuous process for producing barium sulfate , characterized by continuously discharging the barium sulfate without stagnation, and a continuous reactor used therefor.
The present invention has been completed.

That is, the gist of the present invention is as follows: (1) Two or more kinds of raw materials are independently and continuously supplied into a tubular reactor so that the raw materials are mixed and stirred in the reactor. Barium sulfate that is continuously discharged from the reactor without reacting the reaction products
A continuous process arm, of the two or more ingredients, at least one of the raw materials (a) is supplied from a raw material supply port provided at an end portion of the tubular reactor (A), the other The raw material (b) is supplied from at least one or more other raw material supply ports (B) provided at the end or at a downstream side thereof, and has a cross-sectional area ratio defined by the following formula of the tubular reactor. As / Aj is 2 or more
Upper 8 or less, and fluid contact ratio Am / Lj of 0.5 or more 4
A continuous production method of barium sulfate , characterized by performing a reaction having a relative supersaturation (σ) of 10 to 200 , And (2) in a continuous reactor for continuously producing barium sulfate by reacting two or more kinds of raw materials, a tubular reactor;
Two or more raw material supply ports independently provided in the reactor,
A product discharge port for continuously discharging the reaction product is provided, and raw material supply means for supplying a raw material such that the raw materials are mixed and stirred in the reactor is provided. It is composed of a raw material supply port (A) provided at the end of the tubular reactor and a raw material supply port (B) provided at the end or at a downstream side thereof, and is defined by the following formula of the tubular reactor. The cross-sectional area ratio As / Aj is set to 2 or more and 8 or less, and the fluid contact ratio Am / Lj is set to 0.5 or more and 4 or less, and is used for a reaction in which relative supersaturation (σ) is 10 to 200. A continuous production apparatus for barium sulfate .

First, the continuous reactor of the present invention will be described. The continuous reactor of the present invention comprises a tubular reactor as described above, two or more raw material supply ports provided independently of the reactor, and a product discharge port for continuously discharging a reaction product. Provided, the tubular reactor has two or more raw material supply ports on one side,
On the other hand, it has a product outlet and has a structure capable of supplying two or more kinds of raw materials independently. Preferably,
One raw material supply port (A) is provided at the end of the tubular reactor;
The one or more raw material supply ports (B) are provided at the end or at a downstream side thereof, and more preferably, the raw material supply port (B) is provided at the end of the tubular reactor. It is arranged at a predetermined distance from one raw material supply port (A) to the downstream side in the downstream direction. The term “end” as used in the present invention refers to a closed portion on the opposite side to the product discharge port or its vicinity (range 8 in FIG. 1).

Specific examples of such a tubular reactor include:
For example, those shown in FIGS. FIG.
Is a continuous reactor in which a tubular reactor has a raw material supply port (A) at an end of the tubular reactor and another raw material supply port (B) downstream from the end. Is directed toward the product outlet of the reactor. FIG. 2 shows a tubular reactor in which one end is closed and a raw material supply port is provided so that the raw material is supplied into the reactor from a tangential direction of the tube wall of the tubular reactor. In the type that flows toward the discharge port, FIG. 3 shows one end of a tubular reactor that is closed, and a raw material supply port is provided so that the raw material can be ejected toward the closed surface. After changing the direction, the liquid is flowed to the product discharge port, but the direction and the position at which the raw material is ejected are not particularly limited to these. Of the three types mentioned above, the type shown in FIG. 1 is most preferable in view of the difficulty of back mixing and the uniformity of the extrusion flow.

Hereinafter, a preferred example of the continuous reaction apparatus of the present invention will be described in detail with reference to FIG. FIG. 1 shows an example of a reactor section of the continuous reaction apparatus according to the present invention. In the figure, 1 is a raw material supply port (B), 2 is a raw material supply port (A), 3
Is a buffer tank for supplying the raw material, 4 is a run-up section where the fluid supplied from the raw material supply port (A) 2 becomes a piston flow in the tubular reactor 6, and 5 is a raw material supply port (B).
1 is a raw material supply pipe communicating with 1, 1 is a raw material supply pipe communicating with the raw material supply port (A) 2, 6 is a tubular reactor for performing a reaction by mixing and stirring, and 7 is a fluid containing a reaction product. It is a product outlet for discharging to the outside of the tubular reactor 6. Different kinds of raw material fluids are respectively fed by a raw material supply means such as a pump and supplied into the tubular reactor 6 from the raw material supply ports 1 and 2, and the size, shape and number of the raw material supply pipes 5 and 9 are provided. Is not limited. Further, the raw material supply port (B) 1 may be a jet nozzle in order to increase the average linear flow velocity of supply.

The raw material a supplied from the raw material supply port (A) 2
Passes through the run-up section 4 in the tubular reactor 6 and the product outlet 7
Flows in the direction of. At that time, the length of the approach section 4 is determined by the raw material a
However, it is necessary to make the length inside the tubular reactor 6 such that the velocity distribution is substantially uniform in the radial direction, that is, the piston flow. If the velocity distribution is not uniform in the radial direction, the mixing / stirring of the raw material b and the raw material a becomes non-uniform in the radial direction, resulting in a variation in the quality of the product. It is. Raw material supply ports 1, 2
The length of the approach section 4 can be determined by the size, number, and arrangement of the tubular reactors 6, and it is desirable that (length of the approach section 4) ≧ (inner diameter of the tubular reactor 6). . When (length of the run-up section 4) <(inner diameter of the tubular reactor 6), mixing is not uniform in the radial direction due to insufficient piston flow, which causes a problem. Further, in order to sufficiently grow the piston flow, it is desirable that (length of the run-up section 4) ≧ (inner diameter of the tubular reactor 6) × 3. However, if a dispersion plate or the like for uniforming the velocity distribution is inserted and the piston flow can be realized as soon as possible, it is necessary to satisfy (length of the run-up section 4) ≧ (inner diameter of the tubular reactor 6). Absent.

The raw material b is supplied from the raw material supply port (B) 1 into the tubular reactor 6 through the buffer tank 3. Here, the buffer tank 3 only needs to have a size capable of absorbing the pulsation generated by the raw material supply means and supplying the raw material at a uniform pressure at the inlet of the raw material supply pipe 5. Is not limited at all.

The inner diameter and length of the tubular reactor 6 are selected according to the required conditions such as the type of reaction, reaction time, processing capacity, etc., but depending on the number and size of the raw material supply pipes 5 to be installed. The range is limited. The shape of the raw material supply pipe 5 such as a circular pipe, a triangular pipe, and a square pipe is not limited, but a circular pipe is preferable because it is easily available. Also,
The mixing mechanism in the present reactor is because the shear stress develops from the speed difference between the two fluids and the momentum is exchanged between the fluids. The contact area between the fluids is involved. In order to generate this speed difference, the relationship between the flow rates of the liquids to be described later and the relationship between the cross-sectional areas of the flow paths through which the respective fluids flow are also important. Also, 2
The greater the area of contact between fluids, the greater
The stirring is performed promptly, and the reaction product becomes uniform. That is, the cross-sectional area ratio A of the flow channel defined as follows:
The s / Aj and the fluid contact ratio Am / Lj are major factors in producing the continuous reactor of the present invention.

[0018]

(Equation 1)

For example, in the case of a tubular reactor 6 having a circular raw material supply pipe 5, the following calculation is made.

[0020]

(Equation 2)

Here, Dm is the inner diameter of the tubular reactor 6, Dj
Denotes the inner diameter of the raw material supply port 1. According to the study of the present inventors, the cross-sectional area ratio As / Aj is desirably 70 or less in order to perform mixing quickly. If the cross-sectional area ratio As /
When Aj is larger than 70, the inner diameter of the raw material supply port 1 is extremely thin as compared with the tubular reactor 6, and the pressure loss is increased, which is disadvantageous in terms of incidental facilities and operation costs. More preferably, the sectional area ratio As / Aj is desirably 2 or more and 20 or less. If the cross-sectional area ratio is less than 2, it is difficult to obtain a speed difference between the two fluids. Further, the fluid contact ratio Am / Lj is desirably 30 or less. If the fluid contact ratio exceeds 30, the inner diameter of the raw material supply port 1 must be reduced and the number thereof must be increased. Further, preferably, the fluid contact ratio is 1
It is desirably 0 or less. However, the optimum values of the cross-sectional area ratio As / Aj and the fluid contact ratio Am / Lj slightly vary depending on the type of reaction and reaction conditions. For example,
In the reaction of barium sulfate, the cross-sectional area ratio As / Aj is most preferably 2 or more and 8 or less, and the fluid contact ratio Am / Lj is most preferably 0.5 or more and 4 or less.

The continuous reactor of the present invention has a raw material supply means for supplying raw materials to the above-mentioned tubular reactor so that the raw materials are mixed and stirred. Specifically, a liquid sending pump, pressure feeding with a pressurized gas, or the like is used, and is appropriately adjusted so as to satisfy a predetermined condition. That is, in the present invention, the raw material fluid is supplied from the raw material supply ports 1 and 2 into the tubular reactor 6 by the raw material supply means such as a pump, but the raw material a supplied from the raw material supply port 2 is supplied to the pipe reactor. Type reactor 6
It flows in the direction of the product outlet 7 through the approach section 4 in the inside. The raw material b is supplied through a buffer tank 3 from a raw material supply port 1 provided at the tip of a raw material supply pipe 5. Then, the raw material a and the raw material b are mixed and stirred in the tubular reactor 6 to cause a reaction, and the reaction product, by-products and medium are discharged from the product discharge port 7.

At this time, the principle of mixing and stirring in the present invention is that the raw material b is ejected and supplied at a flow rate higher than this flow rate to the raw material a flowing at a low speed. Are mixed and stirred. Thus, in the present invention, not only the mixing of two or more raw materials but also the stirring action utilizing the action of the flow is generated. To explain in more detail, the raw material a flowing at a low speed
The raw material b flowing at high speed is ejected. At this time, 2
In the contact portion between the fluids, a shear stress develops due to the speed difference, the momentum is exchanged, and the low-speed raw material a is taken into the jet raw material b. The entrainment of the flow has a direct effect on the mixing and stirring of the fluid, and the macroscopic mixing and stirring is performed. In addition, the jet is expanded with the entrainment of the jet, and the jet induces a turbulent vortex, and the turbulent vortex spreads across the streamline of the jet, whereby microscopic mixing and stirring progress. Although the turbulent vortices spread in all directions of the flow, the main flow is in the axial direction of the flow, and the transmission of the turbulent vortices in the direction opposite to the flow direction is weak. That is, it can be considered that there is almost no back mixing which is the movement of the fluid in the direction opposite to the flow direction. Therefore, the principle of mixing and stirring in the present invention is:
The difference in velocity of the fluid that causes shear stress between the two fluids is the driving force, and there are two types of mixing and stirring mechanisms: macroscopic mixing and agitation by taking in the low-speed fluid accompanying the jet and microscopic mixing and agitation by the turbulent vortex. It is thought to happen at the same time.

In order to verify this mixing / stirring mechanism, a neutralization reaction of HCl / NaOH having a very high reaction rate (the rate constant of the reaction is 10 ⁸ m ³ mol ^-1 S ^-1 ; Mixing in th
e Process Industries; N. HARNBY, MFEDWARDS, AWN
Using IENOW; Butterworth & Co (Publishers) Ltd, 1985), the progress of the reaction was visually observed from the decolorization of the tracer (phenolphthalein), and the
The stirring state and the mixing time were measured. Specifically, a 0.01 mol / L HCl aqueous solution is used as a raw material a, and a 0.01 mol / L NaOH aqueous solution colored red with phenolphthalein is used as a raw material b. Supply to become
The mixing distance was measured by visually observing the red bleaching state at that time. FIG. 4 shows the results.

In FIG. 4, the horizontal axis represents the average linear flow rate Ub at the raw material supply port 1 when the raw material b is ejected from the raw material supply port 1.
From the raw material a, the average linear flow rate Ua in the vicinity of the raw material supply port 1
, The speed difference Ub-Ua (slip speed) between the two fluids, and the vertical axis indicates the distance (mixing distance) from the raw material supply port 1 until the red color of the tracer disappears. Also, R
-1, R-3 and R-4 indicate the type of the reactor (see Table 1). As can be seen from these results, in order to rapidly mix and stir two fluids in the continuous reaction apparatus of the present invention, the slip speed needs to be 10 cm / sec or more. That is, the slip speed is 10 cm / sec.
When the value is less than 1, it can be seen that the jet flow is extended for a long time due to insufficient development of the shear stress caused by the velocity difference between the fluids, and the mixing and stirring are not performed promptly. Further, when the slip speed is very high, it is desirable for the purpose of mixing and stirring, but it is not desirable due to a large liquid flow rate at the time of supply and equipment problems such as pressure loss and pipe abrasion. Therefore, it is preferable that the slip speed is not less than 10 cm / sec and not more than 500 cm / sec. When these are adjusted by the above-mentioned raw material supply means, it is usually sufficient to change the rotation speed of the pump or change the pressure of the pressurized gas.

The continuous production method of the present invention, using a continuous reaction apparatus as described above, can be suitably performed. Less than,
The production method of the present invention will be described in detail. When the raw materials are supplied, for example, by reacting the raw materials x, y, and z to produce a poorly water-soluble salt, the following embodiments may be mentioned. 1) When x, y, and z are independently supplied. Where x,
Each of y and z is supplied from at least one supply port. 2) When a mixture of x and y and z are independently supplied. However, a mixture of x and y and z are supplied from at least one supply port. 3) As in 2), the mixture of y and z and x are supplied independently. 4) As in 2), a mixture of z and x and y are supplied independently. Of these, for 1), it is necessary to further provide one or more raw material supply ports in the above-described apparatus.
In this case, the position of the additional raw material supply port may be provided at the end of the tubular reactor or downstream thereof depending on the properties of the reaction system.

The poorly water-soluble salt referred to in the present invention refers to Chem. Eng.
Technol. Vol. 11 P.264-276 (1988), the relative supersaturation σ at the time of reaction etc. is 1-1000.
Refers to a salt that is Here, the relative degree of supersaturation is represented by the following equation.

[0028]

(Equation 3)

The continuous reaction of a poorly water-soluble salt of the present invention is to obtain a poorly water-soluble salt by an instantaneous reaction having a relative supersaturation of 1 to 1,000. The degree of supersaturation is desirably 5 to 500. More preferably, 10 to 200 is most desirable.
When the relative supersaturation is less than 1, in the reaction of the poorly water-soluble salt,
Since the reaction concentration becomes extremely dilute, the production efficiency becomes extremely low, which is disadvantageous in the production cost. When the relative supersaturation exceeds 1000, the reaction rate is the fastest among the reactions of poorly water-soluble salts. In order to perform such a reaction, the speed difference between the two fluids must be very large, Need to mix. However, as the speed difference becomes very large, the pressure loss increases, and the equipment and power for liquid feeding increase, which is disadvantageous in cost.

Thus, the relative degree of supersaturation is 1 to 1000
Examples of the raw material for the reaction such as: alkali; Ca (OH) ₂ , Ba (OH) ₂ acid; HF, H ₂ SO ₄ , H ₂ CO ₃ salt; BaCO ₃ , BaCl ₂ , K ₂ CO ₃ , Ag
NO ₃ , KCl, NaClO ₄ , MgCl ₂ , Na ₂ C
₂ O ₄ , Ba (NO ₃ ) _2, NH ₄ F, NiSO ₄ , (N
_{H 4) 2 SO 4, Na} 2 SO 4 alkoxide sites Bu; Ti (OC ₂ H _{5) 4,} such as water, lower alcohols (e.g. methanol, ethanol, those in solution by dissolving in isopropanol) and the like (the raw material fluid) Used.

In the present invention, the relative supersaturation is adjusted to 1 to 1000 by appropriately combining them. When the combination of raw materials having σ of 10 to 200 is specifically shown, the following ( B) to (f).

[0032]

Embedded image

As described above, according to the production method of the present invention,
Despite the use of a tubular reactor that does not have a drive unit or a stirring unit, it is possible to quickly and uniformly mix a fluid after contacting different kinds of fluids. In addition, the residence time distribution is kept very narrow because there is almost no back mixing in the tubular reactor. Furthermore, when the entire inside of the reactor is viewed, the mixed and stirred fluid has a piston flow, and the fluid containing the reaction product is quickly discharged out of the reactor. It has the characteristic that the time to reach a steady state is short.
Due to these features, according to the present invention, a product of uniform quality (particle size, crystal shape, etc.) can be continuously produced even in a reaction producing a very poorly water-soluble salt having a very high reaction rate.

The preferred embodiments of the present invention have been described above. However, in the present invention, the above-mentioned reactors shown in FIGS. 2 and 3 may be used. The action of In the type in which the raw material is supplied from the tangential direction of the tube wall of the tubular reactor of FIG. 2 and flows toward the product outlet while forming a swirling flow, a vortex is formed in the reactor by the swirling flow. After the mixing and stirring are promoted and a uniform reaction field is formed, the generated reaction product can be continuously discharged from the reactor without stagnation.
FIG. 3 shows a type in which the raw material is ejected toward a closed wall surface of the tubular reactor.
Since the flow direction of the fluid changes abruptly, mixing and stirring are performed by forming a complicated velocity distribution state, and similarly, the reaction product can be continuously discharged without stagnation. The present invention is not limited to the above embodiments, and it goes without saying that various modifications are possible within the scope of the claims.

[0035]

EXAMPLES In order to make the contents of the present invention easier to understand,
Hereinafter, examples and comparative examples will be described in more detail. FIG. 5 schematically shows the configuration of the continuous reaction apparatus used in the examples, and Table 1 shows the dimensions and the like of the reactor.

[0036]

[Table 1]

Examples 1-4 Special grade reagent 1465.7 g of barium chloride dihydrate dissolved in 200 liters of ion-exchanged water, 0.03 mol / l barium chloride solution (raw material b), and 585 g of special grade reagent sulfuric acid in deionized water Dissolved in 200 liters.
A 03 mol / liter sulfuric acid solution (raw material a) was prepared in a raw material tank, and the temperature was raised to 60 ° C. When the temperature reached 60 ° C., the solution was charged (ion-exchanged water) in advance, supplied to the reactor preheated to 60 ° C. using a pump, and the flow rate was set with a flow meter. Sampling was performed every 10 seconds from the start of pump operation, and the average particle size was measured. When the reaction was stabilized, the aqueous solution of hydrochloric acid containing the reaction product barium sulfate was all received in the receiving tank. Next, the mixture was cooled to room temperature, filtered through 5C filter paper (manufactured by Toyo Roshi Kaisha, Ltd.), washed thoroughly with ion-exchanged water, and dried. The particle size distribution of the barium sulfate powder thus obtained was measured (a particle size distribution measuring device LA-700, manufactured by Horiba, Ltd.). Table 2 shows the results together with the raw material supply conditions. Incidentally, as an indicator of particle size distribution, average particle size D ₅₀ and _{σg (σg = D 84 / D} 50 by a number basis, D
₅₀ ; 50% particle size on a number basis, D ₈₄ ; particle size corresponding to 84% undersize on a number basis). In addition, in all of Examples 1 to 4, particles having a particle diameter of 10 μm or more are 0.1 μm.
It was less than 1%.

[0038]

[Table 2]

Examples 5 to 6 Special-grade reagents A barium solution (raw material a) of 0.015 mol / l obtained by dissolving 488.56 g of barium chloride dihydrate and 315.5 g of barium hydroxide octahydrate in 200 liters of ion-exchanged water was used. Prepare a 0.015 mol / l sulfuric acid solution (raw material b) prepared by dissolving 294 g of sulfuric acid in 200 liters of ion-exchanged water in a raw material tank. The solution was supplied to the reactor, which had been preheated to ° C, using a pump, and the liquid flow rate was set with a flow meter. Sampling was performed every 10 seconds from the start of pump operation, and the average particle size was measured. When the reaction was stabilized, the aqueous solution of hydrochloric acid containing the reaction product barium sulfate was all received in the receiving tank. Next, the mixture was cooled to room temperature, filtered through 5C filter paper, washed sufficiently with ion-exchanged water, and dried. The particle size distribution of the barium sulfate powder thus obtained was measured (a particle size distribution analyzer LA manufactured by Horiba, Ltd.)
-700). Table 3 shows the results together with the raw material supply conditions.
Shown in As an index indicating the particle size distribution, an average particle size D
₅₀ and σg (same contents as above) were used. In each of the examples 5 to 6, particles having a particle diameter of 10 μm or more were 0.1%.
% Or less.

[0040]

[Table 3]

Examples 7 to 8 Special-grade reagents A barium solution (raw material a) of 0.015 mol / l obtained by dissolving 488.56 g of barium chloride dihydrate and 315.5 g of barium hydroxide octahydrate in 200 liters of ion-exchanged water was used. Prepare a 0.015 mol / l sulfuric acid solution (raw material b) prepared by dissolving 294 g of sulfuric acid in 200 liters of ion-exchanged water in a raw material tank. The solution was supplied to the reactor, which had been preheated to ° C, using a pump, and the liquid flow rate was set with a flow meter. Sampling was performed every 10 seconds from the start of pump operation, and the average particle size was measured. When the reaction was stabilized, the aqueous solution of hydrochloric acid containing the reaction product barium sulfate was all received in the receiving tank. Next, the mixture was cooled to room temperature, filtered through 5C filter paper, washed sufficiently with ion-exchanged water, and dried. The particle size distribution of the barium sulfate powder thus obtained was measured (a particle size distribution analyzer LA manufactured by Horiba, Ltd.)
-700). Table 4 shows the results together with the raw material supply conditions.
Shown in As an index indicating the particle size distribution, an average particle size D
₅₀ and σg (same contents as above) were used. In each of the examples 7 to 8, particles having a particle diameter of 10 μm or more were 0.1 μm.
% Or less.

[0042]

[Table 4]

Example 9 A solution (raw material a) in which 5.7 g of a special grade reagent, Ti (OCH ₂ CH ₃ ) ₄ was prepared per 1 liter of ethanol dehydrated with zeolite (raw material a), and a 2 wt% aqueous ethanol (raw material) b) was prepared in a raw material tank, and when the temperature reached 30 ° C., the solution was charged to a reactor (ion-exchanged water) in advance and supplied to the reactor preheated to 30 ° C. using a pump, and the flow rate was set by a flow meter. did. Sampling was performed every 10 seconds from the start of pump operation, and the average particle size was measured. When the reaction was stabilized, all of the ethanol solution containing TiO ₂ as the reaction product was received in the receiving tank. Then, pore size 0.2μ
m, filtered through a membrane filter (manufactured by Toyo Roshi Kaisha, Ltd.), washed thoroughly with ion-exchanged water, and dried. The particle size distribution of the TiO ₂ powder thus obtained was measured (Horiba Co., Ltd.)
And a particle size distribution analyzer LA-700). Table 5 shows the results together with the raw material supply conditions. In addition, as an index indicating the particle size distribution, the average particle size D ₅₀ and σg (the same content as described above)
Was used.

[0044]

[Table 5]

Comparative Example 1 A special-grade reagent was prepared by dissolving 2.44 g of barium chloride dihydrate and 1.58 g of barium hydroxide octahydrate in 1 liter of ion-exchanged water.
Into a 1-liter separable flask, and in a 1-liter dropping funnel set therein, 1.47 g of sulfuric acid of a special grade was dissolved in 1 liter of ion-exchanged water.
A 15 mol / liter sulfuric acid solution was charged. After the barium solution and the sulfuric acid solution were both heated to 60 ° C., the sulfuric acid solution was added thereto for 1 minute while stirring the separable flask at 200 rpm with a Teflon stirring blade, and the obtained crystals were 5 wt.
The mixture was filtered through filter paper C, washed thoroughly with ion-exchanged water, and dried. This crystal had an average particle size of 1.6 μm, σg = 3.0 defined in the same manner as in Example 1, and had a wide particle size distribution.

Comparative Example 2 Special-grade reagent A barium solution of 0.015 mol / L obtained by dissolving 488.56 g of barium chloride dihydrate and 315.5 g of barium hydroxide octahydrate in 200 L of ion-exchanged water, and 294 g of a special-grade reagent sulfuric acid were used. Ion exchange water 200
A sulfuric acid solution of 0.015 mol / liter dissolved in 1 liter was prepared in a raw material tank, and when the temperature reached 60 ° C., a 20-liter continuous stainless steel tank which had been charged (ion-exchanged water) in advance and preheated to 60 ° C. The reactors were fed at a flow rate of 2 liters / min each using a pump. Sampling was performed every 10 seconds from the start of pump operation, and the average particle size was measured. When the reaction was stabilized, the aqueous solution of hydrochloric acid containing the reaction product barium sulfate was all received in the receiving tank. Next, the mixture was cooled to room temperature, filtered through 5C filter paper, washed sufficiently with ion-exchanged water, and dried. In this case, it took 5 minutes for the grain size of the obtained crystal to reach a steady value. The obtained crystals had an average particle size of 2.1 μm and σg = 2.5 defined in the same manner as in Example 1. However, the crystals had a size of 10 μm or more which was not observed in Examples 1, 2 and Comparative Example 1. The particles are:
It contained 8%.

[0047]

According to the present invention, sulfuric acid, which is a poorly water-soluble salt of uniform size, is suitable for pigments, cosmetics, additives and the like.
Barium can be produced continuously. In addition, the continuous reaction apparatus of the present invention has a stirrer and a drive unit inside the reactor, but rapidly mixes and stirs a fluid as a reaction raw material to cause a reaction, and puts a reaction product into the reactor. Since continuous discharge can be performed without stagnation, the apparatus can be simplified and downsized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a reactor section of a continuous reaction apparatus according to the present invention.

FIG. 2 is a perspective view showing an example of a reactor section of the continuous reaction apparatus of the present invention.

FIG. 3 is a perspective view showing an example of a reactor section of the continuous reaction apparatus of the present invention.

FIG. 4 shows the relationship between the speed difference Ub-Ua (slip speed) and the distance (mixing distance) from the raw material supply port 1 until the red color of the tracer disappears.

FIG. 5 schematically shows the configuration of the continuous reaction apparatus of the present invention used in Examples.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 raw material supply port (B) 2 raw material supply port (A) 3 buffer tank 4 start-up section 5 raw material supply pipe 6 tubular reactor 7 product discharge port 8 end 9 raw material supply pipe 11 raw material tank (raw material a) 12 raw material Tank (raw material b) 13 Pump for sending liquid 14 Flow meter 15 Receiving tank

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B01J 14/00 C01F 11/46

Claims (4)

(57) [Claims] 1. A reaction in which two or more raw materials are independently and continuously supplied into a reactor so that the raw materials are reacted and mixed so that the raw materials are mixed and stirred in a tubular reactor. Sulfuric acid continuously discharged from reactor without stagnation of product
A barium continuous production method, wherein at least one raw material (a) among two or more raw materials is supplied from one raw material supply port (A) provided at an end of a tubular reactor, and The raw material (b) is supplied from at least one or more other raw material supply ports (B) provided at the end or at a downstream side thereof,
And the cross-sectional area ratio As / of the tubular reactor defined by the following equation:
Aj is 2 to 8 and the fluid contact ratio Am / Lj is
0.5 to 4 and relative supersaturation (σ) of 10 to 2
And performing 00 to become reactive, barium sulfate
The method of continuous production arm. 2. A raw material supply port (A) provided at an end of a tubular reactor, at least one or more other raw materials arranged downstream in a predetermined distance from a raw material supply port (A). Supplying another raw material (b) from the supply port (B),
The average linear flow velocity of the other raw material (b) in the raw material supply port (B) is at least 10 cm / sec higher than the average linear flow velocity of the raw material (a) flowing in the tubular reactor in the vicinity of the raw material supply port (B). The method according to claim 1, wherein 3. A method of reacting two or more kinds of raw materials to form barium sulfate.
In a continuous reactor for continuously producing a system, a tubular reactor, two or more raw material supply ports independently provided in the reactor, and a product discharge port for continuously discharging a reaction product are provided. And a raw material supply means for supplying a raw material so that the raw materials are mixed and stirred in the reactor, wherein the raw material supply port is provided at an end of the tubular reactor. (A) and a raw material supply port (B) provided at the end or at the downstream side thereof, and the cross-sectional area ratio As / Aj of the tubular reactor defined by the following equation is 2 to 8 , A continuous apparatus for producing barium sulfate, wherein the apparatus is used for a reaction in which the fluid contact ratio Am / Lj is 0.5 or more and 4 or less and the relative supersaturation (σ) is 10 to 200 . 4. A raw material supply port (B) is provided in a downstream direction at a predetermined distance downstream from one raw material supply port (A) provided at an end of the tubular reactor. The raw material supply means determines that the average linear flow rate of another raw material (b) at the raw material supply port (B) is equal to the raw material (a) supplied from the raw material supply port (A).
10c from the average linear flow velocity near the raw material supply port (B)
4. The continuous production apparatus according to claim 3 , wherein the raw material is supplied so as to be larger than m / sec.