JPS62289215A - Ceramic filter for separating fine particle and its production - Google Patents

Abstract

PURPOSE:To obtain the title filter provided with regularly arranged pores having fixed diameter by bringing many ceramic disks furnished with through pores having 10-several hundreds mum diameter into contact with each other in a closest packed state the outer peripheral surface to the outer peripheral surface, and fusing the disks to each other. CONSTITUTION:A glass tube is heated and melted to produce a thin tube having 10-several hundreds mum diameter, and ceramic paste is coated on the thin tube to produce a ceramic-coated glass thin tube. The ceramic-coated glass thin tubes are bundled by a molding machine so that the outer peripheral faces are brought into contact with each other in a closest packed state, and fused. The material is heated and welded to produce a ceramic-coated glass bundle. The bundle is treated with hydrofluoric acid to volatilize and remove the glass part, and a ceramic green compact is obtained. The compact is baked at high temp. to produce a ceramic base material, and the material is cut to a specified size to obtain the ceramic filter 1 for separating fine particles.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a ceramic filter for separating fine particles and a method for manufacturing the same, and particularly to an improved ceramic filter for separating fine particles having a large number of uniform through-pores and its manufacturing method. Regarding manufacturing methods.

(Prior Art) Conventionally, as a method for separating some components in a fluid including a solid-liquid mixture, reverse osmosis method using a selective permeability filter, ultrafiltration method, dialysis method, liquid permeation method, and gas permeation method have been used. law,
Membrane separation methods such as forward osmosis are known.

Some of the filters used in such membrane separation methods are made of cellulose polymers and other polymer compositions such as polypropylene and polyamide using a solution casting method.
The porous membrane of this filter does not have strong molecular orientation in the membrane surface direction, so its membrane strength is weak, and the membrane itself is formed by increasing the thickness to about 0.1-1 mm. or membrane reinforcing material is used in combination.

In addition to these, the membrane material is specially made with excellent strength resistance, heat resistance, pressure resistance, chemical resistance, etc., and is made of unglazed ceramic with a large number of mesh pores. There is a multi-porous ceramic filter, and a honeycomb-shaped ceramic body is used as a particulate separation ceramic filter to remove particulates from exhaust gas from automobiles and the like.

(Problem to be solved by the invention) However, in conventional filters using polymer membranes, it is difficult to create straight pores with uniform diameters, and the pore paths become irregular. This may cause blockage. Further, there is a problem that the membrane strength is low and it is necessary to use a reinforcing material or increase the thickness a.

In addition, in the case of an unglazed ceramic filter having a large number of mesh-like pores, the pore diameter is not uniform over all the pore passages, but varies in width and narrowness in two parts.
During separation, solid particles to be separated clogged the middle of the hole, making it impossible to efficiently separate them.

Conventional particulate filters made of unglazed ceramic have weak mechanical strength because pores of various diameters, wide and narrow, are formed three-dimensionally and irregularly. It becomes extremely weak against

As described above, conventional porous polymer membranes, ceramic filters, and methods of manufacturing the same have many problems that must be solved technically.

(Means for Solving the Problems) The present invention has been made in view of the above-mentioned problems, and is a ceramic filter for particulate laboratories having a high porosity and uniform through-pores of 10 to several hundred micrometers. The present invention provides a ceramic filter for separating fine particles that has excellent mechanical strength, corrosion resistance, abrasion resistance, etc., and whose surface is difficult for foreign substances to adhere to, and a method for manufacturing the same.

That is, (1) a large number of thin, micro-diameter ceramic discs each having through-holes with a diameter of 10 μm to several 100 μm are brought into contact and fused in a close-packed state on the outer peripheral surfaces of each disc. A ceramic filter for separating fine particles and (2) a glass tube are heated and melted in a drawing furnace to form a particle size of 10 μm to several 100 μm.
A glass capillary coating process involves manufacturing a capillary tube, passing the capillary tube through a coating die and covering it with a ceramic paste to produce a ceramic coated glass capillary tube. filling condition,
A focusing process in which a ceramic-coated glass capillary tube bundle is manufactured by focusing the glass tubes in contact with and fusing together, heating and explosion bonding, and then treating the ceramic-coated glass bundle with hydrofluoric acid to volatilize and remove the glass portion. an HF treatment step for producing a ceramic green molded body; a firing step for producing a ceramic dielectric body by firing the ceramic green molded body at a high temperature;
A method for manufacturing a ceramic filter for separating fine particles, comprising a finishing step of cutting the ceramic body into a predetermined size in a direction intersecting a large number of through pores to manufacture a ceramic filter for separating fine particles. .

The material of the ceramic filter of the present invention is submicron particle cordierite, AI20s, 5iC1S.
It is mainly composed of one or more types of ceramics such as isN1 and AIN, as well as a small amount of sintering aid and thermal expansion coefficient iI! It may also contain a conditioning agent and the like.

Ceramic paste is made by adding a binder and a sintering agent to powdered ceramic raw materials that will become ceramic filters in the future. As the ceramic raw material, one or more types of ceramic powders such as cordierite powder, alumina powder, silicon nitride powder, silicon carbide powder, and aluminum nitride powder can be used, or metals such as nickel, cobalt, and tungsten can be used. A cermet can also be made by mixing powders.

As the binder, well-known ones such as polyvinyl alcohol and polyvinyl butyral are used, and as the sintering agent, an appropriate one is selected depending on each ceramic. For example, for silicon nitride, MgO1Cao, AI203,
Y20s etc. are used.

In addition, the glass tube used in the manufacture of this ceramic filter for particulate separation may be made of a composition material that is eroded and eliminated by a chemical reaction in the subsequent hydrofluoric acid treatment process, such as borosilicate glass, lead glass, etc. , S i
It may also be made of quartz glass or the like made only of Ot.

To make a glass capillary, for example, a well-known capillary manufacturing method can be used in which wire drawing is performed while heating at a high temperature, and the diameter of the capillary obtained by this method is at least 10
About a μ ring, maximum number 1001. t m, a filter with a predetermined diameter can be manufactured according to the required separation diameter size as a filter.

A predetermined array of ceramic-coated glass capillary tubes is produced by covering the glass capillaries with a coating die to a thickness of several microns to several tens of microns with ceramic and converging several thousand to tens of thousands of them.

Note that the ceramic-coated glass capillary bundle can be arranged in a hexagonal arrangement in a close-packed state.

If an arrangement method is adopted in which ceramic fibers are regularly arranged and interposed at regular intervals in the gaps between these arrangements, the porosity can be appropriately adjusted to about 70% to 30%.

Furthermore, the glass part of the ceramic-coated glass capillary bundle is removed with 30% hydrofluoric acid to make the glass capillary part the pore size of the ceramic filter, but even though the hydrogen fluoride used is a gas, In this way, a ceramic green molded body can be obtained, which may be an aqueous solution.

Thereafter, the ceramic green molded body is sintered by firing at a high temperature.

For example, in the case of cordierite, a ceramic body having a large number of through pores is produced by firing at around 1350°C.

In this case, in the present invention, when the ceramic green molded body is dried and fired, the volume thereof is usually several percent to several ten percent.
As it contracts, many through pores also contract.
It becomes a through pore with a smaller pore.

Finally, the ceramic body is cut to form a ceramic filter of an appropriate thickness. A diamond cutter or the like is used for cutting, and the cutting direction is cut so that it intersects the many through-holes. A ceramic filter for products having a large number of filter pores is obtained.

Its structure consists of a large number of thin ceramic disks with small diameters having through-holes of 10 μla to 100 μm in diameter, which are brought into contact and fused in a close-packed state on the outer peripheral surfaces of each disk. It consists of a triangular transparent light. The ceramic filter for separating fine particles of the present invention produced in this way can be used as a thin plate ceramic filter for separating mixtures such as solid-liquid and solid-gas by selecting the material and the diameter of the through-pores. It has a significant effect. In particular, solid particles with a particle size in the range of several micrometers to several thousand micrometers, such as silicon carbide, carbon, alumina, various natural minerals, synthetic minerals, and metal powders such as titanium, molybdenum, and copper, are prepared at each particle size stage. Suitable for fractionating liquids such as water, mineral oil, vegetable oil, alcohol, and organic substance dissolved solutions, and for fractionating into each particle size stage, the ceramic filter of the present invention having various through-pores, for example, By using a combination of a 50 μm diameter ceramic filter and an 80 μm diameter ceramic filter, it is possible to separate only particles with a 50 μm diameter to 80 μm diameter.

Further, regarding the separation of gel-like substances and gases in a liquid, the necessary substances can be separated by adjusting the operating conditions depending on the type, distribution range of particle size composition, and classification range.

In the separation process, the solids content of the mixture of objects to be separated is preferably 50% or less, but the separation can be carried out under optimal separation conditions by appropriately adjusting the separation rate depending on the particle size distribution.

(Example) Embodiments of the present invention will be specifically explained below based on the drawings.

FIG. 1 is a perspective view of a ceramic filter for separating fine particles according to the present invention, and FIGS. 2 (A) to (E) are schematic illustrations of the manufacturing process of a ceramic filter for separating fine particles according to an embodiment of the present invention.

In (a) of Fig. 2, the ceramic-coated glass capillary 4
For manufacturing, the borosilicate glass tube 2 is heated in an electric furnace 8 at 1150"C.
The pipe is heated to a predetermined diameter (20 μ-
A glass capillary having a diameter of ~300 μm) and a wall thickness (10 μm to 150 μm) is drawn, and then coated with ceramic paste 3 in a coating die 9 to produce a ceramic-coated glass capillary tube 4.

In (b) of FIG. 2, the ceramic-coated glass capillary tubes 4 are bundled into about 50,000 pieces in an electric furnace at 8° and heat-welded to form a cylindrical ceramic-coated glass capillary bundle having a length of cll and a diameter of am. 5 is produced.

In (c) of FIG. 2, the glass capillary bundle 5 is
A ceramic green molded body 6 is obtained by immersing it in 30% hydrofluoric acid at a temperature of 0.degree. C. for 5 hours to volatilize and remove the glass portion.

Ceramic paste 3 is a mixture of 85% cordierite with submicron particle size and 5% kaolin, 3% CaO as a sintering agent, 5% polyvinyl butyral as a binder, and butyl phthaloyl butyl glycol as a solvent. It was kneaded using etc.

In (d) of FIG. 2, the ceramic green molded body 6 is fired at 1300° C. for 3 hours to form a ceramic body 7.

In (e) of FIG. 2, the ceramic body 7 is 2,0
A large number of uniform through-pores of the present invention are cut to about 1°.
A ceramic filter 1 (FIG. 1) for separating fine particles is manufactured.

Through-hole 1 with a pore diameter of 45μ manufactured as described above
' (The pores initially had a diameter of 50 μm, but shrunk during the drying and firing steps during production.) Not only can it completely separate and remove dissimilar solid substances, but it also has high mechanical strength, so pressure filtration can be performed and separation efficiency can be increased.

The equipped ceramic filter 1 for separating fine particles contains an organic polymer component l! Unlike +i membranes and bisque-like ceramic filters, it is made of a ceramic body in which pores of a specific pore size are formed in a straight line, and the standard accuracy is also constant, making it possible to filter solids, etc. of a certain particle size. It can be separated into characteristics based on efficiency.

(Effects of the Invention) As explained in detail in the Examples and the like, the present invention has mechanical strength,
It is a ceramic filter for separating fine particles that has excellent corrosion resistance, abrasion resistance, high temperature resistance, etc., and has regularly arranged pores of a constant diameter.The ceramic filter of the present invention can be used to easily and reliably separate minute solid particles of a specific size. can be separated and sorted, and processes such as industrial cleaning waste liquid treatment and air purification treatment can be carried out with high efficiency.

In addition, even if foreign substances adhere to the membrane surface of this filter and its properties deteriorate, the filter can be heated to burn out the foreign substances, or by applying back pressure or suction to the filter 3. It can be easily recycled and reused, extending its useful life by 21 days.

It is a ceramic filter for separating fine particles that has a large number of through pores with a pore diameter of about 10 μm to several 100 μm (fine and uniform), and because the pores have a linear and uniform diameter, there is no possibility of clogging during the separation operation. It is possible to achieve highly accurate reflux filtration with less filtration, and it is also useful for making the filtration device more compact.

Furthermore, according to the manufacturing method of the present invention, a ceramic filter for particulate separation that is suitable for continuous production and has uniform through-pores made of a ceramic material with excellent corrosion resistance, abrasion resistance, and high temperature resistance can be efficiently produced. can be manufactured.

As described above, the present invention exhibits novel and excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a ceramic filter for separating fine particles according to the present invention, and FIGS. 2(A) to (E) are schematic illustrations of the manufacturing process of a ceramic filter for separating fine particles according to an embodiment of the present invention. 1: Ceramic filter for separating fine particles 1°: Through pores 2 Glass tube 3: Ceramic paste 4: Ceramic coated glass capillary tube 5; Ceramic coated glass capillary tube bundle 6: Ceramic green molded body 7: Ceramic body 8.8': '; [Air furnace 9: Coating die 10: Molding machine patent applicant Systimni Gyo Co., Ltd. Agent Patent attorney Mura 1) Yukio Figure 2 (Glass tube coating process) (c) (d) (1-EF treatment process) (firing process) (q
new process)

Claims (1)

[Scope of Claims] (1) A large number of thin, micro-diameter ceramic discs having through-holes with diameters of 10 μm to several 100 μm are brought into contact and fused together in a close-packed state on the outer peripheral surfaces of each disc. A ceramic filter for separating fine particles characterized by the following structure. (2) The ceramic filter for particulate separation according to claim 1, wherein the composition of the ceramic body is mainly composed of cordierite. (3) The composition of the ceramic body is mainly composed of SiC, Si_3N_4, AIN,
The ceramic filter for separating fine particles according to claim 1, characterized in that it is made of one or more types of Al_2O_3. (4) A glass capillary coating step in which a glass tube is heated and melted in a drawing furnace to produce a capillary with a size of 10 μm to several 100 μm, and the capillary is passed through a coating die to be coated with ceramic paste to produce a ceramic-coated glass capillary. a convergence step of producing a ceramic-coated glass capillary bundle by heating and welding the ceramic-coated glass capillaries in a molding machine so that their outer circumferential surfaces contact and fuse in a close-packed state; An HF treatment process in which a covered glass bundle is treated with hydrofluoric acid to volatilize and remove the glass portion to produce a ceramic green molded body, and a firing process in which the ceramic green molded body is fired at a high temperature to produce a ceramic body. and,
A method for manufacturing a ceramic filter for separating particulates, comprising a finishing step of manufacturing a ceramic filter for separating particulates by cutting the ceramic body into a predetermined size in a direction intersecting a large number of through pores.