KR101284405B1 - Manufacturing method of metallic hollow fiber having porosity - Google Patents

Abstract

Since the porous metal hollow fiber filter medium of the present invention does not use a polymer as a pore generating agent, it does not need to undergo a separate oxidation process, thereby reducing production cost and production time, and also generates carbides after the sintering process. I never do that.

Description

Manufacturing method of porous hollow fiber filter medium {Manufacturing method of metallic hollow fiber having porosity}

The present invention relates to a method of manufacturing a metal hollow fiber filter medium having a porosity, and more particularly, to a method of manufacturing a metal hollow fiber filter medium in which carbonization of a polymer does not occur.

Hollow fiber membrane is generally manufactured in the form of a thread having a central part like a macaroni. It is mainly used as a permeable membrane for removing fine impurities, and can be classified into a polymer hollow fiber membrane, a ceramic hollow fiber membrane, and a metal hollow fiber membrane. .

In general, the polymer hollow fiber metal hollow fiber filter medium has a weak tensile strength and thus a high risk of cutting, and it is difficult to recover the permeate flow rate by a backwashing method when contamination of the membrane occurs. In addition, there is a risk that the pores are collapsed by high backwash pressure, and in the case of chemical washing, there was a problem in changing the form and physical properties of the pores.

Furthermore, the polymer hollow fiber metal hollow fiber filter medium is not high in temperature resistance and cannot be used for high temperature treatment materials. In the case of the reinforcement type hollow fiber metal hollow fiber filter medium without the risk of cutting, when backwashed by a backwash method, There was a problem that the polymer metal hollow fiber filter medium coating layer peeled off from the reinforcing material and could not be used. In the case of the ceramic metal hollow fiber filter medium which has improved such a conventional problem, the disadvantages of the polymer metal hollow fiber filter medium can be overcome to some extent, but the use of the ceramic metal hollow fiber filter medium is very limited due to the problem of cracking during use.

Metal hollow fiber filter media is produced in GKN, Germany, mainly in the form of a tube, but it is not spinning but uses a method of pressing and molding metal particles in a certain frame and then sintering at high temperature and high pressure. It is used only in special cases that cannot be used as a polymer metal hollow fiber filter because it has a low packing density per unit volume because of its high diameter and very large diameter compared to the polymer hollow fiber filter medium. It is becoming. In addition, in the case of manufacturing by sintering after inserting the metal powder into the molding die, the production process is complicated, the production efficiency is reduced, and in the process of forming a multilayer, a relatively small particle size powder penetrates into the interior to reduce the porosity There was a problem.

In order to overcome the problems of the manufacturing process of the metal-metal hollow fiber filter medium by the powder sintering method, Korean Patent No. 10-0562043 discloses a manufacturing method of metal hollow fiber by the spinning method. The spinning method can reduce the production cost more than 30% compared to the powder sintering method described above, and can be widely used in the industrial field due to the high packing density per unit volume. By the way, the Korean Patent No. 10-0562043 describes only a method for manufacturing single layer hollow fiber using a single spinning nozzle. Specifically, Figure 1a is a cross-sectional view of a single spinning nozzle (1) used in the conventional spinning method, the single spinning nozzle is formed in the center of the seal 2 and the outer peripheral portion of the seal 2 and the spinning liquid is injected It is divided into a spinneret (3). The metal hollow fiber precursor may be prepared by injecting a spinning solution including a metal powder into the single spinning nozzle 1 and spinning the same. Figure 1b is another single spinning nozzle as an internal coagulating solution injection unit 5 for injecting an internal coagulating solution such as water to form a hollow in the center and the spinneret (6) ) Is formed.

On the other hand, in order to form the pores of the metal hollow fiber through the above-described pressure firing method and spinning method, the polymer is mixed with the metal powder, and the polymer is oxidized at a relatively high temperature to form pores through the site where the polymer is oxidized. However, the pressure firing method and the spinning method for manufacturing the metal hollow fiber is basically a mixture of the metal powder and the polymer to form a void and the oxidation process at 400 ~ 800 ℃ temperature of the oxidation of the polymer (temperature at which the polymer is burned and volatilized) After performing the voids to form a sintering process again at 1200 ℃ or more. However, in the case of using a polymer as a pore-forming agent, not only has to undergo a separate oxidation process in order to form voids, but also some polymers have a problem that the polymer carbide remains in the final product even after the sintering process without carbonization occurs.

The present invention has been made to solve the above problems, the first problem to be solved of the present invention is to provide a method for producing a metal hollow fiber filter medium that does not undergo a separate oxidation process and does not produce a carbonization of the polymer. .

The second problem to be solved of the present invention is to provide an apparatus for ship ballast water treatment employing the multilayer metal hollow fiber filter medium of the present invention.

In order to solve the first problem described above, the present invention (1) Preparing a metal hollow fiber comprising dispersing a nonferrous metal that is easily corroded by an acid as a pore forming agent; And (2) immersing the metal hollow fiber in a corrosion solution containing an acid to corrode the nonferrous metal to form a plurality of pores in the metal hollow fiber.

According to a preferred embodiment of the present invention, the metal hollow fiber may be any one or more of nickel, titanium, aluminum, copper and stainless steel.

According to another preferred embodiment of the present invention, the non-ferrous metal may be any one or more of magnesium, brass and new stock.

According to another preferred embodiment of the present invention, the metal hollow yarn of step (1) may include 2 to 30% by weight of non-ferrous metal.

According to another preferred embodiment of the present invention, the acid of step (2) may be any one or more selected from the group consisting of sulfuric acid, nitric acid, acetic acid, hydrochloric acid and chromic acid.

According to another preferred embodiment of the present invention, the metal hollow fiber of step (1) may be prepared by mixing a transition metal and a non-ferrous metal in a polar solvent and spinning the mixture through a spinning nozzle.

According to another preferred embodiment of the present invention, the metal hollow fiber may be a multilayer metal hollow fiber.

According to another preferred embodiment of the present invention, the diameter of the hollow of the metal hollow yarn may be 0.5 ~ 10 mm.

According to another preferred embodiment of the present invention, step (2) may be repeated 2 to 5 times.

According to another preferred embodiment of the present invention, there is provided an apparatus for treating a ballast water vessel comprising the metal hollow fiber filter medium of the present invention.

Since the porous metal hollow fiber filter medium of the present invention does not use a polymer as a pore generating agent, it does not need to undergo a separate oxidation process, thereby reducing production cost and production time, and also generates carbides after the sintering process. I never do that.

1A and 1B are cross-sectional views of a single spinning nozzle used for spinning a conventional hollow metal fiber.
2 is a cross-sectional view of a dual spinning nozzle according to a preferred embodiment of the present invention.
3 is a cross-sectional view of a triple spinning nozzle according to a preferred embodiment of the present invention.
4 is a cross-sectional view of a triple spinning nozzle according to another preferred embodiment of the present invention.
5 is a cross-sectional view of a quadruple spinning nozzle according to another preferred embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings the present invention will be described in more detail.

As described above, the pressure firing method and the spinning method for manufacturing a conventional metal hollow fiber are basically a mixture of the metal powder and the polymer to form a void and the oxidation of the polymer (temperature at which the polymer is burned and volatilized) 400 ~ 800 After the oxidation process is carried out at ℃ ℃ to form a void is subjected to a sintering process at 1200 ℃ or more. However, in the case of using a polymer as a pore-forming agent, not only has to undergo a separate oxidation process in order to form voids, but also some polymers have a problem that the polymer carbide remains in the final product even after the sintering process without carbonization occurs.

In the present invention 1) Preparing a metal hollow fiber comprising a non-ferrous metal dispersed easily by acid as a pore-forming agent; And (2) immersing the metal hollow fiber in a corrosion solution containing an acid to corrode the nonferrous metal to form a plurality of pores in the metal hollow fiber. As a result, since the polymer is not used as a pore-generating agent, there is no need to undergo a separate oxidation process, thereby reducing production cost and production time, and no carbide is generated even after the sintering process.

The manufacturing method of the metal hollow yarn of the present invention is conventional except that non-ferrous metal easily corroded by acid as a pore-forming agent and then forming a void by immersing a metal hollow fiber containing a non-ferrous metal in a corrosion solution containing an acid. The manufacturing method of metal hollow fiber can be applied. Therefore, preferably, the metal powder and the non-ferrous metal are mixed in a hollow fiber mold like the sintering method, and then, firstly calcined to prepare a metal hollow fiber precursor, and the precursor is pressed and sintered to prepare a metal hollow fiber or manufactured by spinning. It is also possible to make and other methods known in the art are also well known to those skilled in the art.

Hereinafter, the method of manufacturing the metal hollow fiber of the present invention through the spinning method, but is not limited thereto.

First, (1) Inside as a step And preparing a metal hollow fiber comprising a non-ferrous metal dispersed easily by acid as a pore-forming agent. To this end, as a step (a), any one or more metal powders and nonferrous metal powders selected from the group consisting of transition metals, oxides and alloys thereof are dispersed in a solvent to prepare a metal precursor solution.

The metal powder which can be used in the present invention can be used alone or in combination of transition metals, oxides and alloys thereof which can be used in metal hollow fibers. Preferably, the transition metal may be a 3 to 5 cycle transition metal, more preferably the transition metal may be any one of nickel, titanium, aluminum, copper, stainless steel, most preferably the metal to be produced It is more preferable to use nickel which is very inexpensive, so that the manufacturing cost can be considerably lowered and the uniformity of pore size can be secured.

In addition, the particle size of the metal powder is preferably maintained in the average particle diameter range of 0.005 ~ 20 ㎛, if the particle size is less than 0.005 ㎛ the unit cost of the metal powder is too high economic efficiency and it is difficult to increase the content of the metal powder The strength of the final metal film is significantly reduced and there is a problem that sintering is not performed. When the thickness exceeds 20 μm, the pore size is formed to be 5 μm or more, so that the pore is too large to be used for water treatment. It is desirable to maintain.

The present invention includes a nonferrous metal which is easily corroded by acid as a pore forming agent in place of a polymer. Non-ferrous metals can be used without limitation as long as they can be easily corroded by acid in the manufacture of hollow metal, and can form voids. Non-ferrous metals can be used without limitation, and preferably magnesium and brass. And may be any one or more of the new stock, but is not limited thereto.

In addition, the amount of the non-ferrous metal relative to the mixture of the entire metal powder and the nonferrous metal may be 2 to 30% by weight.

The solvent for dissolving the metal powder and the nonferrous metal is specifically selected from the group consisting of N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide and dimethyl sulfoxide, 1-tridecanol and terpinol. It may be any one or more. The amount of the solvent may be appropriately used to the extent that the metal hollow fiber precursor can be produced by spinning, and preferably, 25 to 80 parts by weight of the solvent may be used based on 100 parts by weight of the mixture of the metal powder and the nonferrous metal. If it is less than 25 parts by weight, it is difficult to uniformly dissolve the metal powder and polymer, and thus, it is difficult to prepare the metal hollow fiber precursor. If it exceeds 80 parts by weight, the viscosity of the spinning solution is very weak, making nozzle spinning difficult and the strength of the manufactured metal hollow fiber Can be lowered.

Next, in step (2), the metal precursor solution is spun using a spinning nozzle to prepare a metal hollow fiber precursor. In this case, a single layer hollow fiber is manufactured using the spinning nozzles disclosed in FIGS. 1A and 1B, or a multilayer metal hollow fiber precursor is produced by spinning through a multispinning nozzle. The multi-spinning nozzle that can be used in the present invention is not particularly limited as long as it can produce a multi-layered metal hollow fiber, preferably, the multi-spinning nozzle is a double spinning nozzle or provided with a seal for forming a hollow inside It may be a triple spinning nozzle, it may be a triple spinning nozzle or a quadruple spinning nozzle when the internal coagulating solution injection unit is provided to form a hollow therein. On the other hand, the internal coagulation solution that can be used in the present invention can be used without limitation as long as it is conventionally used, preferably a polar solvent such as water and N-methyl-2-pyrrolidone, DMAc or an organic solvent such as ethanol, isopropanol May be used alone or in combination.

First, a multi-spinning nozzle having a closed portion formed therein for hollow formation will be described. FIG. 2 is a cross-sectional view of a double spinning nozzle 10 according to a preferred embodiment of the present invention. The first injection part 12 which forms the inner layer of the two-layer hollow fiber on the outer peripheral surface centering on (11), and the 2nd injection part 14 which forms the outer layer of the two-layer hollow yarn on the outer peripheral surface of the 1st injection part 12. Is provided, the partition wall 13 for the interlayer separation is formed between the first injection portion 12 and the second injection portion 14.

The size of the double-layered nozzles to be used can be appropriately formed in accordance with the size of the construction of the two-layered metal to be manufactured, and the thickness of the partition wall is also larger than the thickness of the partition wall of a conventional double- It may be formed to be thin, and preferably 0.5 to 3 mm.

Figure 3 is a cross-sectional view of a triple spinning nozzle formed with a seal according to a preferred embodiment of the present invention. The first injection part 22 which forms the 1st layer of a three-layer hollow fiber on the outer peripheral surface centering on the sealing part 21 which forms the hollow part of hollow fiber inside, and the 2nd layer on the outer peripheral surface of the 1st injection part 22 The second injection unit 24 is formed to form a first partition wall between the first injection unit 22 and the second injection unit 24 is formed. In addition, a third injection unit 26 is formed on the outer circumferential surface of the second injection unit 24 to form an interlayer between the second injection unit 24 and the third injection unit 26. The second partition 25 is formed.

Next, referring to the multi-spinning nozzle formed therein the internal coagulating liquid injection portion for forming the hollow, Figure 4 is a cross-sectional view of a triple spinning nozzle 300 according to a preferred embodiment of the present invention, the hollow hollow inside A first injection unit 303 is formed on the outer circumferential surface of the inner coagulating liquid injection unit 301 to form an inner layer of the hollow fiber, and is formed between the internal coagulating liquid injection unit 301 and the first injection unit 303. The first partition 302 may be provided. A second injection part 305 for forming an outer layer of a two-layer hollow fiber is provided on the outer circumferential surface of the first injection part 303 and an interlayer separation is formed between the first injection part 303 and the second injection part 305 A second barrier rib 304 is formed for radiating a two-layer metal construction.

The size of the triple spinning nozzle to be used can be appropriately formed according to the size of the two-layer metal hollow fiber to be manufactured, and the thickness of the first and second partition walls is also a conventional double spinning nozzle to improve the interlayer peeling force. It may be thinner than the thickness of the partition wall, and may be preferably 0.5 to 3mm.

FIG. 5 is a cross-sectional view of the quadruple spinning nozzle 400. A third injection unit 403 forming an inner layer of a three-layer hollow yarn on an outer circumferential surface of an inner coagulating liquid injection unit 401 forming a hollow yarn therein is provided. The third partition 402 may be provided between the internal coagulating solution injection part 401 and the third injection part 403. A third injection unit 403 is provided with a first injection unit 405 forming an intermediate layer of a three-layer hollow fiber on the outer circumferential surface of the third injection unit 403 and an interlayer distinction is formed between the third injection unit 403 and the first injection unit 405 A first barrier rib 404 is formed. A second injection part 407 for forming an outer layer of a three-layer hollow fiber is provided on the outer circumferential surface of the first injection part 405 and an interlayer separation is formed between the first injection part 405 and the second injection part 407 A second barrier rib 406 may be formed.

The multilayer metal hollow fiber filter medium manufactured by the above-described method does not generate interlayer penetration. That is, the metal powder forming the first metal filtration layer does not penetrate into the second metal filtration layer or the metal powder forming the second metal filtration layer does not penetrate into the first metal filtration layer. In addition, even when the third metal filtration layer is formed, interlayer penetration does not occur in the same manner.

According to a preferred embodiment of the present invention, when the metal precursor solution is radiated to the dual spinneret, the average particle diameter of the metal powder of the metal precursor solution injected into the first injection part and the average particle diameter of the metal precursor solution The average particle size of the metal powder may be different. In this case, the size and porosity of the pores of the outer layer and the inner layer of the finally produced two-layer metal hollow fiber can be controlled differently, and the filtration efficiency can be remarkably improved.

According to another preferred embodiment of the present invention, when the metal precursor solution is radiated to the double spinning nozzle, the metal precursor solution to be injected into the second injection portion with respect to the center is mixed with two or more kinds of metal powders having different average particle diameters Can be added.

Preferably, the average particle diameter of the metal powder to be injected into the second injection part can be divided into two or more kinds. The first metal powder having an average particle diameter of 0.005 to 5 μm and the second metal powder having an average particle diameter of 3 to 20 μm And the average particle diameter of the second metal powder may be 0.5 mu m or more larger than the average particle diameter of the first metal powder.

The coagulation bath for coagulating the spinning solution after spinning may use alcohol, water and a specific solvent. However, it is preferable to consider water in terms of economics. In this case, if the temperature of the coagulation bath is lower than 0 ° C., the precursor after spinning is rapidly reduced. It may be coagulated and cause a slight crack in the precursor. If it exceeds 70 ° C, the solvent vaporizes and is harmful to the body. Therefore, the temperature of the water-based coagulation bath is preferably maintained in the range of 0 to 70 ° C.

Metal hollow fiber produced through this is 0.5 ~ 10 ㎜ in diameter of the hollow and to include a non-ferrous metal dispersed therein.

As a next step (3) (2) the spun metal hollow fiber is immersed in a corrosion solution containing an acid to corrode the nonferrous metal to form a plurality of pores in the metal hollow fiber. Corrosion liquid used at this time can be used without limitation as long as it can corrode the non-ferrous metal contained in the metal hollow fiber, preferably the acid of step (2) includes sulfuric acid, nitric acid, acetic acid, hydrochloric acid and chromic acid alone or mixed You can, but are not limited to this. Corrosion solution immersion can be performed once but may be repeated 2 or 5 times or more times, and the corrosion time may be 1 to 3 hours, but is not limited thereto.

Next, as a step (4), the hollow metal may be manufactured by sintering the hollow hollow metal. Specifically, in the case of the metal hollow fiber including the polymer as a conventional pore-forming agent, in order to manufacture by spinning method, the oxidation process of the polymer must be performed before the sintering process. However, since the present invention does not include a polymer, it is possible to manufacture the metal hollow fiber through a sintering process without going through a separate oxidation process. Preferably, the sintering temperature of the step (4) may be 700 ~ 1400 ℃, the gas atmosphere may be used alone or in a mixture of nitrogen, argon, hydrogen and the like as a conventional atmosphere. The sintering time may be 1-4 hours.

 Through the sintering process, the metal hollow fiber precursor shrinks by about 20%, thereby securing necessary strength and reducing the pore size.

On the other hand, it has been described to perform the sintering process after the corrosion solution immersion process when manufacturing the metal hollow fiber through the spinning method, on the contrary, it is also possible to form a void by performing the corrosion solution immersion process after the sintering process. However, shrinkage occurs through the sintering process, and the effect of reducing the voids by about 20% occurs. In consideration of this, it may be advantageous to perform the sintering process after the voids are formed.

The multi-layered metal hollow fiber produced through the present invention can be widely used in water treatment filters, microfiltration filters, vessel ballast water treatment apparatus and the like.

The following examples illustrate the invention in more detail. The following examples are presented to help the understanding of the present invention, but the present invention is not limited thereto.

≪ Example 1 >

A first metal precursor solution to form an inner layer was prepared. Specifically, 100 parts by weight of nickel powder having an average particle diameter of 5 μm and 9 parts by weight of brass powder were added to 34.3 parts by weight of N-methyl-2-pyrrolidone and stirred at 700 rpm to prepare a first metal precursor solution.

A second metal precursor solution was formed to form the outer layer. Specifically, 100 parts by weight of nickel powder having an average particle diameter of 2.5 μm. 10 parts by weight of brass powder was added to 42 parts by weight of N-methyl-2-pyrrolidone and stirred at 700 rpm to prepare a second metal precursor solution.

Water was supplied to the internal coagulation solution injection unit of the triple spinning nozzle disclosed in FIG. 4, a first metal precursor solution was added to the first injection unit, and a second metal precursor solution was added to the second injection unit. In this case, the diameter of the inner coagulating solution injection part is 0.7 mm, the diameter of the second injection part (including the inner coagulating solution injection part) is 2.6 mm, the diameter of the third injection part (including the inner coagulating solution injection part and the first injection part) Is 3.2 mm.

The spun metal hollow fiber precursor is then coagulated in distilled water. Thereafter, the precursor was immersed in water for one day and removed by exchange of solvent and water. Thereafter, the metal hollow fiber precursor was immersed twice in 15% nitric acid solution for 1 hour and then immersed twice in 20% hydrochloric acid solution for 30 minutes to corrode the brass to form pores. Thereafter, the metal hollow fiber in which the pores were formed was sintered under a nitrogen / hydrogen atmosphere. Specifically, the sintering was completed by maintaining at 1250 ℃, 2 hours to cool to 10 ℃ / min to prepare a double metal hollow fiber filter medium.

The manufactured double metal hollow fiber filter medium had a hollow of 1.0 mm, a first metal filtration layer (inner layer) having a thickness of 338 µm, an average size of pores of 3.8 µm, and a porosity of 41%. In addition, the thickness of the second metal filtration layer (outer layer) is 2.6 μm, the average size of pores is 1.5 μm, and the porosity is 32%. As a result of observing the cross section of the double metal hollow fiber filter medium, no interpenetration occurred and no carbide was observed.

<Example 2>

A double metal hollow fiber filter medium was prepared in the same manner as in Example 1 except that the new powder was used instead of the brass powder.

The prepared double metal hollow fiber filter medium had a hollow of 1.0 mm, a first metal filtration layer (inner layer) having a thickness of 341 μm, an average size of pores of 4.2 μm, and a porosity of 37%. In addition, the thickness of the second metal filtration layer (outer layer) is 2.6 µm, the average size of the pores is 2.1 µm, and the porosity is 24%. As a result of observing the cross section of the double metal hollow fiber filter medium, no interpenetration occurred and no carbide was observed.

The metal hollow fiber filter medium produced through the present invention can be widely used in water treatment filters, vessel ballast water treatment devices, and the like.

10: double spinning nozzle 11: sealing part
12: first injection portion 13: partition wall
14: second injection unit

Claims (10)

(One) Preparing a metal hollow fiber comprising dispersing a nonferrous metal that is easily corroded by an acid as a pore forming agent; And
(2) immersing the metal hollow fiber in a corrosion solution containing an acid to corrode the nonferrous metal to form a plurality of voids in the metal hollow fiber;
The hollow metal hollow fiber of step (1) is a method for producing a porous metal hollow fiber filter medium, characterized in that the mixture of the transition metal and the non-ferrous metal in a polar solvent was produced by spinning through a spinning nozzle. The method of claim 1,
The metal hollow fiber is a method of producing a porous metal hollow fiber filter medium, characterized in that any one or more of nickel, titanium, aluminum, copper and stainless steel. The method of claim 1,
The non-ferrous metal is a method for producing a porous metal hollow fiber filter medium, characterized in that any one or more of magnesium, brass and new stock. The method of claim 1,
Method for producing a porous metal hollow fiber filter medium, characterized in that the hollow metal yarn of step (1) comprises a non-ferrous metal of 2 to 30% by weight. The method of claim 1,
The acid of step (2) is a method for producing a porous metal hollow fiber filter medium, characterized in that any one or more selected from the group consisting of sulfuric acid, nitric acid, acetic acid, hydrochloric acid and chromic acid. delete The method of claim 1,
The metal hollow fiber is a method for producing a porous metal hollow fiber filter medium, characterized in that the multi-layer metal hollow fiber. The method of claim 1,
The diameter of the hollow of the metal hollow yarn is a method of producing a porous metal hollow fiber filter medium, characterized in that 0.5 to 10 mm. The method of claim 1,
Step (2) is a method for producing a porous metal hollow fiber filter medium, characterized in that it is repeated 2 to 5 times. delete

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