JPS6283030A - Apparatus for preparing inorganic globular particle containing different kinds of fine powder - Google Patents

Abstract

PURPOSE:To facilitate filtering and to enable the reuse of a surfactant, by applying a reaction product to a centrifugal separator to separate the same into an org. solvent and an aqueous suspension containing scum, water, fine globular particles and a small amount of the org. solvent. CONSTITUTION:An aqueous sodium silicate solution and pigment are charged in a mixing tank 1 to prepare a suspension. A solvent and a surfactant are supplied to a mixing tank 2 and the solvent separated by a centrifugal separator 5 is charged in said tank 2. The substances issued from the mixing tanks 1, 2 are mixed in a mixing tank 3 to prepare a W/O type dispersion which in turn reaches a reaction tank 4. When an aqueous ammonium sulfate solution is supplied to the reaction tank 4 to hold the pH of said dispersion to about 7, reaction is generated at every dispersed aqueous liquid particles to form a dispersion having fine spherical particles formed therein. When this dispersion is allowed to stand, said dispersion is separated into two layers wherein an upper layer is the solvent and a lower layer is water and formed fine spherical particles are sedimented to the lower part of the water layer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application: The present invention involves the use of water-soluble glycol, which is a first reactant, which is a gel skeleton donor, and a surfactant in an organic solvent that is poorly soluble in water. In addition, a milk suspension is prepared, and an aqueous solution of a second reactant containing a precipitating agent is added thereto,
This invention relates to a series of production equipment that reacts to produce poorly water-soluble spherical fine particles and separates them. Hereinafter, for the sake of simplicity, a case will be described in which a different type of fine powder is mixed with a pigment.

The first reactant, the second reactant, the pigment, the surfactant, the organic solvent, etc. are described in Japanese Patent Publication No. 54-6251, and the present invention provides an industrial production apparatus for the same. It is.

The term "slightly soluble" as used in the present invention includes both slightly soluble and substantially insoluble cases, and is a simplified expression of "insoluble or poorly soluble."

Prior art: The spreading method and properties of spherical inorganic fine particles (spherical 1-year-old particles) are described in detail in the Osaka Industrial Research Institute Quarterly, Vol. 30, pp. 18-24 (1982), and Japanese Patent Publication No. 54-6251 describes a laboratory method for producing a spherical porous fine powder containing t-gold, a pigment for anticorrosive and antifouling paints. For example, according to Example 5, pigment (, i
(2:3 mixed powder of mercury oxide and steel oxide) 100 f/ was added to the first reactant (sodium silicate) aqueous solution (5i024
mol/l) to 500 sl and stir for 10 minutes to make a homogeneous suspension. This was mixed with an organic solvent (r-7) f6M of the surfactant (sorbitan monooleate),
(l f/1001 solution 1 &) 1 g and shaken for 5 minutes on a shaker to explode the W/'O type milk suspension. This milk suspension is added to the second reactant (ammonium sulfate) aqueous solution (i molz4') 41 with stirring, and reacted for 30 minutes. After the reaction, filtration, washing with water, and drying (110°C, 24 hours) were performed to obtain porous spherical fine powder 220
g (paraffinic hydrocarbons are preferred as the organic solvent for the reasons described later).

Although the present invention provides an apparatus for industrially producing gold-containing inorganic spherical fine powder such as the pigment represented by the above embodiment, no such apparatus exists to date.

Problems to be Solved: In order to specifically explain the problem, the industrial production of the above example will be explained. Even if the type of surfactant changes, it is possible to use the same equipment in practice, and this is not a limitation.

In the present invention, a pigment or the like is added to a high water solution of the first reactant to form a suspension, and an organic solvent in which a surfactant is dissolved is added to this suspension to form a ψ-type dispersion. This is reacted with the water bath liquid of the second reactant under stirring to produce spherical fine particles containing pigment, etc., and the organic solvent (accompanied surfactant) is removed from the reaction product. )f! : Collecting, separating and purifying spherical fine water particles, and removing scum generated at the interface between the organic solvent layer and the water layer. In the absence of scum formation, or in negligible amounts, it should be possible to eliminate scum removal devices, but no such surfactants have been developed to date. Most of the scum exists at the interface between the solvent layer and the water layer and is difficult to remove. In addition, spherical fine particles are
The typical diameter is from several micrometers to several tens of micrometers, making it extremely difficult to filter as is.

Means for solving the problem: In the present invention, the reaction product is (a) centrifuged to form an aqueous solution containing an organic solvent, scum, water (aqueous solution), spherical fine particles, and a small amount of organic solvent. Separate into suspensions (b)
This aqueous suspension is heated as necessary to form sifloc by particle condensation, (→ Separate the formed floc by filtration, and) If necessary, the floc is washed with an organic solvent to form spherical fine particles. Organic substances attached to the surface (based on surfactants)
(2) Dry and grind to produce a product.

In the centrifugal separator, if necessary, water generated during filtration, or fresh water such as well water or seawater, is transferred to the scum suspension side. Submit to the department.

Effect: In the centrifuge, the return water undergoes radially outward liquid movement 1
1 to entrain the scum to the aqueous suspension side.

If you heat the aqueous suspension, 1. The fine powder coagulates and becomes fume, making filtration much easier.

By collecting and reusing the surfactant, the surfactant dissolved in the solvent can be reused.

Example: FIG. 1 shows a process diagram of one example of implementing the present invention. Sodium silicate (first reactant) aqueous solution (810! 4 + n
ol/#) at a ratio of 2# of pigment (or a fragrance or other compound) to 1#/ of pigment to create a suspension. Solvents (toluene, cyclohexane, hexane, etc.) and surfactants (cow esters such as fatty acid esters of sorbitan, semi-ethers such as cellosolve calpitol, etc.) are supplied to a mixing tank (2). For mixing [(2), in addition to the above, a centrifuge (5
) The separated solvent is charged and mixed. Mixed 'a (
The substances exiting from 1) and (2) are thoroughly mixed in mixing step (3) to form a W70 type dispersion liquid and reach reaction tank (4).

To the reaction tank (4), anthonium sulfate (g2 reactant) aqueous solution (1 mol/l as (Nd4) 2S04)
The reaction tank (pi) is maintained at about 7.
), a reaction occurs in each dispersed aqueous droplet, producing a spherical imitator (5i02 containing all pigments, etc.), and a dispersion thereof is obtained. When this product is allowed to stand still, it separates into two layers: the upper layer is the I5 agent and the lower layer is water (aqueous solution). The resulting spherical fine particles precipitate at the bottom of the aqueous phase. In addition, scum (lI!! cloudy solid) caused by the surfactant used is present in the upper and lower liquid layers! Occurs near the IP-plane. The amount of scum produced varies depending on the type and amount of surfactant used.

A centrifuge (5) is used to facilitate the static separation.

An example of the structure of a centrifugal separator is shown in FIG. Reaction tank (4)
The product enters through the valve into a fixed central tube (closed at the right end) having a plurality of openings. Fixed central tube (
The closed right end of 2) extends to the right and is rotatably held on the central axis (54a) of the rotating body (goods). The rotating body is rotatably held in journal parts (s4b) and (54b'), and has a hollow cylindrical body (54d) waiting for end plates (54c) and (54c'), and a hollow cylindrical body (54d) arranged around the outer cylindrical surface. The hollow cylindrical body (54d) includes a helical body (54e) and a plurality of nine holes (SZa) bored in the hollow cylinder (54d). Truncated hollow cone with end plate (2
) is fixed, and its conical inner surface is a helix (5
48) to move the solids precipitated at the bottom of the water layer (radially outermost) to the right. The casing accommodates the fixed central tube, the rotating body 1 and the fixed hollow cone body, and has a solvent outlet (57a) and a water layer (containing abrasive granules) outlet (
57b).

The reaction products entering the fixed central tube through the valve ψ1) pass through the opening (52a) to the helical body (54e) and the annular chamber (rotating hollow cylinder). , (formed by the outer wall of S4a) and the inner wall of the fixed hollow cone (2)). In the soil, the reaction products form a solvent layer on the inside and a water layer on the outside due to centrifugal force, and scum collects near the interface of both layers, forming a spherical shape on the outermost side of the water layer. Fine particles settle. The helical body (s4e) has the effect of moving the water layer containing the spherical particles from the left to the right in the figure. The solvent layer moves to the left and exits.
From J (s7a), the water layer containing spherical particles is at the outlet (5
7b). From the valve (51a), the water (aqueous solution) after the spherical fine particles have been removed (the filtrate of the filter (6) in FIG. 1) or fresh water is mixed into the reaction product into the annular chamber). It is possible to increase the velocity of the fluid moving from the left to the right within the tank, reduce the content rate kq/i of scum and spherical fine particles, and allow both to flow out to the water outlet.

Outlet (s7a) 'c The solvent that comes out contains the dissolved surfactant and is returned to the mixing tank (2) in Figure 1 to replenish the lost solvent and surfactant and mix #I (3) will be sent to It is desirable that a part of the solvent that is circulated and reused be carefully treated by distillation, chemical treatment, etc. to prevent the solvent from becoming contaminated. Since I don't have one, I won't go into details.

As a solvent, paraffin group hydrocarbons, especially n-hexane, are desirable because they have a low specific gravity and can easily separate the scum, the difference in specific gravity from the aqueous layer makes it easy to separate, and they are inexpensive. The specific gravity and polarity increase around J of the group/aromatic disease.) However, this does not apply.

The aqueous layer forming material flowing out from the outlet (57b) in FIG. 2 is sent to the heat treatment device (6) in FIG. The aqueous layer product is heated to 600-toOQ by ↓ air in the heat treater (6).
heated to c. Solvent and water are almost incompatible, so when the vapor pressure of the solvent, the vapor pressure of the water, and the sum of D become equal to the device pressure (atmospheric pressure), boiling (heterophase azeotrope) occurs,
Solvent removal is possible at relatively low temperatures.

(6a) is an indirect cooler, and (6b) is a separation tank for the four agents and water. In heat treatment 4 (6), spherical fine particles and scum! Yojj! It turns out to be 70 ri (coarse grain). The upper layer water is discharged and removed or sent to a scum filter (7) to remove the scum. The descum-removed water is returned to the heat treater (6) or discharged, depending on the situation. The lower layer water, which is spherical fine particles, in the heat treatment device (6) is
It direct passer (8) I/C to 9
It is separated into filtrate and filtrate, which are made up of spherical particles. Part of the filtrate is discharged, and the other part is sent to a centrifuge (5
) (to the valve (51a) in FIG. 2).

hmm .

The gas phase of the mixing tank (2), mixing tank (3), reaction tank (4), centrifugal separator (5), and heat treatment machine (6) contains solvent vapor, and when air coexists, combustion and Because there is a risk of explosion, it is desirable to have a sealed structure that is isolated from the atmosphere, and to maintain it above atmospheric pressure with an inert gas (such as N2). Also,
By the reaction between the first reactant and the second reactant, N)I8′J
If this occurs (e.g. in the case of the reaction between sodium silicate and ammonium sulfate), an inert gas is added, e.g. The solvent is circulated through the solvent separation tank (6b) and the head of the hermitage 2 mixing tank (2), and a dilute sulfuric acid washer is inserted into the communication pipe between the reaction tank (4) and the centrifugal separator (5). NH8 (NH
,) It is desirable to remove them as 2So4 (in order to make the drawing clearer, these pipes and cleaners should not be omitted)
Q: As a scum filter (7) and a spherical fine powder filter (8),
For centrifugation, a filtration machine, a filter press, etc. are convenient, but the method is not limited thereto. (9) is a spherical fine powder washer, αQ is a dryer,
qD is a grinder. If the degree of contamination of the spherical particles is not important, the washer (9) is removed and 11! There is also a method in which the filter dregs are washed in the filter (8).

In the above embodiments, continuous operation or semi-continuous operation (for example, batch operation of filters (7), (8), etc.) is assumed, but in devices with a relatively small throughput, quarter operation may be required. In some cases, it may be desirable to increase the amount of water, regardless of whether the operation is continuous or batchwise.

Effect of the invention: The method for producing spherical fine particles, which is the object of the present invention, includes spherical fine particles, contents such as additives, and scum as a solid phase, and water (aqueous solution) and a solvent as a liquid phase. A complex system that generates inert gas (gas that does not substantially contain oxygen, N2, etc.), combustible/explosive 7U agent vapor, and even 8 gases depending on the combination of reactants is created in the gas phase. We handle it.

In general, to separate an n-component mixture, (n, -1
However, for components (C) which are not involved in the reaction and can be recycled and used (in the present invention, solvents), the number of separation devices in the circulation path should be as small as possible. Desirably, in the present invention, after the reaction, a centrifuge is used to recover the solvent (dissolved surfactant is also recovered at this time).

In addition, heat treatment (6
0 to less than 100℃, virtually no boiling occurs)
and condensation, making the filtration operation extremely simple.

[Brief explanation of drawings]

FIG. 1 is an example of a flow sheet for the 4R construction of the pigment-containing spherical fine particles of the present invention. FIG. 2 shows an example of the structure of a centrifugal separator used in the present invention. (1)... Granite mixing tank (2)... 2 cypress mixing (3)... Rope 3 mixing tank (4)... Reaction tank (5)
... Centrifugal separator (6) ... Heat treatment tank (7)
... Scum separator (8) ... Spherical particulate filter (
9)...Cleaning device αq...Drying device (B)・
··Crusher

Claims (1)

[Claims] 1. A first reactant aqueous solution which is a gel skeleton donor;
A dispersion liquid is prepared by dispersing the heterogeneous fine powder in a solvent that contains a surfactant and is poorly soluble in water; An aqueous solution of the second reactant, which is a precipitating agent, is added to the dispersion liquid to form the heterogeneous fine powder. In an apparatus for separating and recovering spherical fine particles, the apparatus produces (a) a W/O type dispersion using an aqueous solution of the first reactant, a different type of fine powder, a solvent, and a surfactant; (b) a reactor for reacting the W/O type dispersion produced in the apparatus with a second reactant aqueous solution to produce spherical fine particles; (c) a reaction product of the reactor. (d) A transport member for reusing the solvent; (e) A device for removing scum from an aqueous solution holding the spherical particles and scum after the solvent has been removed. and a filter for separating and recovering the spherical fine particles from the lower layer of the aqueous solution. 2. The apparatus according to claim 1, wherein the aqueous solution holding the spherical fine particles and scum after removing the solvent described in (e) is maintained at a temperature of 60 to 100°C. 3. The device according to claim 1 or 2, wherein the dissimilar fine powder is a pigment. 4. The device according to claim 1 or 2, wherein the foreign fine powder is a capsule containing another substance. 5. The apparatus for producing a W/O type dispersion according to claim 1 (a) comprises: (a) a first mixing tank for producing a suspension of a first reactant and a different type of fine powder; b) a second mixing tank for dissolving or dispersing the surfactant in a solvent to create a solution or dispersion, and (c) a suspension produced in the first mixing tank and a solution or dispersion produced in the second tank. The device according to any one of claims 1 to 4, comprising a third mixing tank for producing a W/O type dispersion by mixing the liquid and the liquid. 6. Adding the filtrate of the filter or fresh water as set forth in claim 1(e) to the reaction product to be treated in the centrifugal separator set forth in claim 1(c), to obtain water from the reaction product. 6. Apparatus according to any one of claims 1 to 5 for phase augmentation. 7. The device according to any one of claims 1 to 6, wherein the first reactant according to claim 1 is sodium silicate, and the second reactant is ammonium sulfate. 8. Any one of claims 1 to 7, wherein the solvent according to claim 1 has a paraffin hydrocarbon having a boiling point of 100°C or less at atmospheric pressure as a main component. The device described in. 9. The device according to any one of claims 1 to 8, wherein the surfactant according to claim 1 is a fatty acid ester of sorbitan.