JP2005118771A - Cylindrical ceramic porous body, method for manufacturing the same, and ceramic filter using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a ceramic porous body which is provided with a highly reliable separation membrane and has high separability and permeability and strength. <P>SOLUTION: This ceramic porous body has 1.5-2.5 mm thickness and ≥40 MPa flexural strength and is provided with the porous separation membrane having 0.04-0.3 μm average pore size and 30-50% porosity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a ceramic porous body, a ceramic filter using the same, and a manufacturing method thereof.

  Ceramic porous bodies used for filtration filters, etc. are superior in heat resistance, corrosion resistance, durability and physical strength compared to organic polymer membranes used for similar applications, while filter filtration performance Therefore, it is necessary to control the pore size so that the separation performance and the permeation performance, which are important characteristics, can be satisfied simultaneously in a single layer.

  As a technique for controlling the pore diameter, a porous ceramic material having a uniform and bulky structure is disclosed in which the porosity and the pore diameter are controlled by adding a pore-forming agent to the ceramic raw material, and then burning away during firing to form pores. (Patent Document 1). However, in the porous ceramic material disclosed in Patent Document 1, since the porosity and the pore diameter are controlled by the pore forming agent, the debinding time is longer than usual in order to burn out the pore forming agent at the firing stage. In addition, there is a problem that leads to defects such as cracks if the conditions are not appropriate. Moreover, since the influence of the pressure loss of the liquid or gas to be filtered is large, there is a problem that the required separation performance and strength cannot be obtained if priority is given to the permeation performance.

  Therefore, as a means for satisfying separation performance, permeation performance, and strength, a plurality of porous thin films having smaller pore diameters are formed as separation layers on the outer peripheral surface of a substrate made of a porous body having a relatively large pore diameter. The method is commonly used. A number of such multi-layer membrane technologies have been disclosed, but an inorganic porous membrane is formed by coating a suspension containing inorganic particles on one side of a porous support to form a separation layer, and drying and firing. Is disclosed (Patent Document 2).

  In addition, the filter is often cleaned by backflow cleaning, but in some cases, it may be by steam cleaning or heat cleaning, and a method of forming a separation layer by coating a suspension on one side of the support. However, there is a problem that peeling or cracking at the interface between the support and the separation layer is likely to occur when placed in an environment where heat shock is applied as described above. As an improvement measure, for example, FIG. As shown in a), a two-layer extrusion method using a mold 111 is disclosed (Patent Document 3).

  According to this, a green laminated molded body 118 as shown in FIG. 4B is obtained by extruding the electrode filling 115 and the separator filling 116 from the base 112 by the plunger 117, and obtained. Further, it is shown that a laminated sintered body is produced by firing the green laminated molded body 118.

In addition, a two-layered porous material having a pore size of 1 to 50 μm of the support and a pore size of 0.01 to 10 μm of the separation membrane is also disclosed, and the shape of a disk, a sheet, a tube, and an extruded columnar material is disclosed. It is shown that it is preferable to use the porous body for a filter (Patent Document 4).
JP 11-322465 A JP-A-7-163848 Japanese Patent Laid-Open No. 9-259905 JP-A-2-95423

  However, the thing of the said patent document 2 has the problem that a fatal defect, such as a crack and a pinhole, is easy to generate | occur | produce since the separation layer formed on a porous support body is a thin film. Further, in order to satisfy the separation performance, it is necessary to make the inorganic particles contained in the suspension finer, so that there is a problem that the porosity of the separation layer is low and the permeation performance is lowered.

  Further, the laminate produced by extrusion molding shown in Patent Document 3 is a plate-like body, and the electrode fill soil 115 and the separator fill soil 116 that form the green laminate molded body 118 are continuously connected to one base 112. The laminated body 118 is extruded and the laminated body 118 is integrally sintered to produce a laminated sintered body. Further, in order to prevent the bending of the laminated body 118 and to prevent the positions of both molded body interfaces from deviating, the hardness of the electrode filling earth 115 and the separator filling earth 116 is set to 10 to 14, And although it is also disclosed that the difference is 2 or less, according to these methods, a step of providing a bonding material layer at the interface or pressurizing after molding is necessary in order to bring the layers into close contact with each other. . For this reason, the laminate shape is limited to a plate shape, and it has been difficult to apply to a multi-layered cylindrical ceramic porous body.

  And in patent document 4, the pore diameter of the support body (support body) of the two-layer porous body containing a cylindrical body is 1-50 micrometers, and the pore diameter of the inorganic membrane (separation membrane) joined to this is 0.01- Although it is described that it is 10 μm, in order to achieve the pore size range of the inorganic membrane, a raw material powder having an average particle size of about 0.1 to 5 μm must be used, and inorganic particles are contained in the support pores. There was a problem that the membrane particles permeated and the permeation performance was remarkably lowered. Further, when a carrier having a pore diameter of 20 μm or more is used, there is a problem that a sufficient strength as a filter application cannot be obtained and a uniform film formation of an inorganic film is difficult, so that the film is likely to be defective. Moreover, in the said patent document 4, the reason for limitation of the suitable range of the pore diameter of a support body and an inorganic membrane and the manufacturing method by extrusion molding are not specified, and it was not usable.

  Therefore, in the present invention, a high-performance cylindrical ceramic porous body having a highly reliable separation layer of a thick film and having characteristics of high separation performance, permeation performance, and high strength, and a ceramic using the same The purpose is to provide a filter.

  As a result of repeated investigations on the above problems, the present inventor, in particular, the particle size and particle size distribution of raw materials used as a support and a separation membrane, the thickness of the separation membrane and the entire porous body, the molding method, the firing temperature, etc. However, it has been found that the separation performance, permeation performance, and strength as a ceramic porous body are achieved by controlling to satisfy these specific conditions. It came.

  The cylindrical ceramic porous body of the present invention is a cylindrical ceramic porous body comprising a separation membrane on the surface of a cylindrical support, and the separation membrane has a thickness of 0.05 mm to 0.5 mm. It is characterized by comprising one or more inorganic porous separation membranes having an average pore size of 0.04 μm to 0.3 μm, a maximum pore size of 0.4 μm or less, and a porosity of 30 to 50%.

Further, the cylindrical ceramic porous body has a thickness of 1.5 to 2.5 mm, a bending strength of 40 MPa or more, and an air permeation amount at a pressure of 500 KPa of 1.0 L / min / cm ² or more. To do.

  In the method for producing a cylindrical ceramic porous body of the present invention, the cylindrical ceramic porous body comprises a separation membrane on the surface of a cylindrical support, and the average particle diameter of the support is 3.0 μm to A raw material made of 9.0 μm ceramic powder was used, and the separation membrane was made of ceramic powder having an average particle size of 0.4 μm to 2.5 μm. A cylindrical ceramic molded body is prepared, and the cylindrical ceramic molded body is fired at a temperature of 1200 ° C to 1600 ° C.

  Further, the ceramic powder constituting the separation membrane has a D90 / D10 ratio of 3 or less, where D10 and D90 are the particle sizes corresponding to 10% cumulative and 90% cumulative from the small diameter side of the particle size distribution, respectively. And

  Further, in the extrusion molding, when the discharge amount of the ceramic powder as the support is V1, and the discharge amount of the ceramic powder as the separation membrane is V2, the V1 / V2 ratio is 1.5-40. It is characterized by being molded in the range of

  The ceramic filter of the present invention is characterized by using the ceramic porous body.

  The cylindrical ceramic porous body of the present invention is reliable against membrane defects such as pinholes and cracks because the separation membrane provided on the surface of the cylindrical support is 0.05 mm to 0.5 mm thick. It can be used stably for a long period of time. Moreover, although it has a thick separation membrane, it has the separation performance and permeation performance which were excellent as a filter by setting it as the above structures.

  Further, according to the method for producing a porous body of the present invention, a cylindrical ceramic porous body comprising a separation membrane on the surface of a cylindrical support is integrally molded and fired simultaneously by extrusion, There is no need to add a filming process, leading to a reduction in man-hours. Moreover, since both the separation membrane and the support are supplied as clay, the problem that the separation membrane particles enter the pores of the support can be prevented. Further, since the ratio V1 / V2 of the discharge amount V1 of the ceramic powder serving as the support and the discharge amount V2 of the ceramic powder serving as the separation membrane is set to 1.5 to 40, a high performance and highly reliable membrane can be obtained. Can do. That is, since V1 / V2 was set to 1.5 or more, an increase in pressure loss due to an excessively thick film and a decrease in permeation performance can be prevented, and the ratio V1 / V2 was set to 40 or less. Occurrence of defects such as membrane breakage and cracks due to the separation membrane being formed on the support can be prevented.

  Hereinafter, the cylindrical ceramic porous body according to the present invention will be described in detail.

  FIG. 1 is a perspective view showing an example of a cylindrical ceramic porous body 1 of the present invention.

  The cylindrical ceramic porous body 1 of the present invention carries (stacks) an inorganic porous separation membrane (hereinafter simply referred to as a separation membrane) 3 having a thickness t1 on the surface of a cylindrical ceramic porous support 2; The total thickness is t, and filtration is possible by allowing fluid to permeate from the separation membrane 3 side toward the support 2 side.

  As a feature of the present invention, the separation membrane 3 of the cylindrical ceramic porous body 1 has a thickness t1 of 0.05 mm to 0.5 mm, an average pore diameter of 0.04 μm to 0.3 μm, and a maximum pore diameter of 0.4 μm or less. The layer is composed of a single layer or a plurality of layers of an inorganic porous material having a porosity of 30 to 50%.

  Here, the reason why the thickness t1 of the separation membrane 3 is set to 0.05 mm to 0.5 mm is that if the thickness t1 is less than 0.05 mm, the film thickness is thin, which causes defects such as tears and cracks, and reliability. This is because if the thickness exceeds 0.5 mm, the pressure loss increases, and the permeation performance of the entire ceramic porous body decreases.

  Moreover, the reason why the average pore diameter of the separation membrane 3 is set to 0.04 μm to 0.3 μm is that, when the average pore diameter is less than 0.04 μm, the pore diameter is too small and the permeation performance is deteriorated. This is because when the pore diameter exceeds 0.3 μm, the separation performance is degraded. Moreover, the separation performance with respect to viruses, clays, bacteria, and algae can be exhibited by doing in this way.

  And by making the maximum pore diameter 0.4 μm or less, particularly when the ceramic porous body of the present invention is used as a ceramic filter for industrial water / wastewater treatment, it exhibits excellent separation performance and has a size of about 0.5 μm pseudomonas (a kind of bacteria) and the like can be accurately removed.

  Furthermore, the porosity is set to 30% to 50% because it is not preferable because the permeation performance is lowered when the porosity is less than 30%, and when it exceeds 50%, the strength is lowered and defects are caused. Because it is connected.

The cylindrical ceramic porous body 1 has a thickness of 1.5 to 2.5 mm, a flexural strength of 40 MPa or more, and an air permeation amount of 1.0 L / min / cm ² or more when pressurized at 500 KPa. And

  In the present invention, the thickness t of the cylindrical ceramic porous body 1 is set to 1.5 mm to 2.5 mm. When the thickness t is less than 1.5 mm, the porous body can be ensured in permeation performance. This is because if the thickness is too small, the strength of the porous body cannot be satisfied because the thickness is thin, and if the thickness exceeds 2.5 mm, the firing temperature is sufficient to ensure the separation performance of the porous body. This is because the pressure loss due to the thickness is increased and the pressure loss due to the thickness is increased, which is not preferable because the permeation performance of the entire porous body is deteriorated.

  The reason why the bending strength of the cylindrical ceramic porous body 1 is 40 MPa or more is that if it is less than 40 MPa, the durability and physical strength, which are the characteristics of the ceramic filter, cannot be utilized.

By controlling the above-mentioned elements, the air permeation amount at the time of pressurization of 500 KPa can be set to 1.0 L / min / cm ² or more. Sufficient filtration capacity can be secured.

  Next, another embodiment of the present invention is shown in FIG. 2A is a cross-sectional view including a separation membrane 3 on one side of a cylindrical ceramic porous support 2, and FIG. 2B is one of the cylindrical ceramic porous support 2. FIG. 2C is a cross-sectional view including the separation membranes 31 and 32 on both side surfaces of the cylindrical ceramic porous support 2. .

  As described above, the cylindrical ceramic porous body 1 of the present invention has the above-described excellent separation performance and permeation performance by adopting a two-layer structure of the support and the separation membrane as shown in FIG. If the variation in film thickness becomes a problem, the separation membranes 31 and 32 can be made into a multi-layer structure of two or more layers as shown in FIGS. Variations can be reduced. Further, the shape of the cylindrical ceramic porous body 1 of the present invention may be either a substantially cylindrical shape including an ellipse (hereinafter not shown) or a polygonal cylindrical shape.

  Moreover, by using the above-mentioned cylindrical ceramic porous body 1 as a ceramic filter, it is excellent in strength, permeability and separation performance as a filter for industrial water and wastewater treatment as well as a filter for water supply. It can be used as a ceramic filter.

  Next, the manufacturing method of this invention is demonstrated.

  As shown in the cross-sectional view of FIG. 3 (a), the method for producing a ceramic porous body according to the present invention is applied to a mold 11 consisting of a cylindrical outer core 13, an inner core 14, and a base 12 for supporting body 2. The ceramic powder kneaded material 15 and the ceramic powder kneaded material 16 for the separation membrane 3 are charged, and both raw materials are simultaneously integrally formed by extrusion to obtain a multi-layered cylindrical molded body. Here, the separation membrane discharge port 19 in which the clays 15 and 16 are integrated is provided in the base part 12, and the length L of the base 12 is 10 to 15 mm. In this way, the separation membrane clay 16 is supplied alone to the base part 12 and is integrated with the support body clay 15 at the base part 12, whereby the inner surface of the mold 11 and the filling soil 16 of the separation membrane 3 are separated. Friction can be reduced, and separation of the separation membrane 3 due to friction can be prevented. Further, a plurality of discharge ports 19 of the separation membrane filling 16 are provided at equal intervals on the circumference, thereby suppressing variations in the thickness t1 of the separation membrane 3 in the circumferential direction.

  The cylindrical ceramic porous body 1 is produced by firing the cylindrical molded body thus obtained at a temperature of 1200 ° C to 1600 ° C.

  Here, FIG. 3A shows an example of a mold 11 for producing the ceramic porous body 1 having a cylindrical two-layer structure of the support 2 and the separation membrane 3, and FIG. 2B and FIG. The structure of two or more layers shown can also be manufactured in the same manner. That is, as shown in FIG. 3 (b), the outer core portion 13 of the mold 11 is provided with the respective channels of the clay 22 for forming the separation membrane 31 and the clay 23 for forming the separation membrane 32. What is necessary is just to arrange the discharge port 25 of the clay 23 in front of the 22 discharge ports 19.

  Thus, since the cylindrical ceramic porous body 1 is integrally formed by extrusion molding, no separate membrane attaching process is required, and both the separation membrane 3 and the support 2 are supplied as clay. Therefore, it is possible to prevent a problem that the membrane particles enter the pores of the support.

  The ceramic powder clay 15 forming the cylindrical ceramic porous support 2 is made of a ceramic powder having an average particle size of 3.0 μm to 9.0 μm, and the ceramic powder forming the separation membrane 3 is made of a ceramic powder. The clay 16 has an average particle size of 0.4 μm to 2.5 μm, a particle size distribution corresponding to 10% from the small diameter side and a particle size corresponding to 90% accumulated as D10 and D90, respectively, and the D90 / D10 ratio is 3. The raw material consisting of the following ceramic powder is used.

  That is, the ceramic powder forming the separation membrane has an average particle size of 0.4 μm to 2.5 μm, and in the particle size distribution of the ceramic powder, the ceramic powder corresponding to 10% cumulative and 90% cumulative from the small diameter side. By setting the ratio of D90 / D10 to be 3 or less when the particle diameters are D10 and D90, respectively, the separation membrane is supported on a ceramic porous support, and in the range of 1200 ° C to 1600 ° C. It has been found that by firing, the aforementioned average pore diameter can be 0.04 μm to 0.3 μm, the maximum pore diameter is 0.4 μm or less, and the porosity is 30 to 50%.

  And when the firing temperature of the cylindrical molded body is set to 1200 ° C. to 1600 ° C., when the range is exceeded, the average pore diameter, the maximum pore diameter, the permeation performance, the bending strength of the ceramic porous body, This is because at least one of them is not satisfactory.

  The appropriate firing temperature range varies depending on the average particle size of the ceramic powder used. For example, a raw material made of ceramic powder having an average particle size of 3.0 μm or more and less than 6.0 μm is used for the ceramic porous support. When a raw material made of ceramic powder having an average particle size of 0.4 μm or more and less than 1.5 μm is used for the separation membrane, the average particle size of the ceramic porous support is 6.0 μm or more and 7.5 μm. 1400 ° C to 1550 ° C, the average particle size of the ceramic porous support is used in the case of using a raw material consisting of ceramic powder of less than 1 μm and a ceramic powder having an average particle size of 1.5 μm or more and less than 2.0 μm for the separation membrane. A ceramic powder having a diameter of 7.5 μm or more and less than 9.0 μm is used, and the ceramic powder is 2.0 m or more and less than 2.5 μm for a separation membrane. When using the raw material which consists of, the range of 1450 to 1600 degreeC is more preferable.

  The extrusion molding has a V1 / V2 ratio of 1.5 when a discharge amount of the ceramic powder filling 15 serving as the support 2 is V1, and a discharge amount of the ceramic powder filling 16 serving as the separation membrane 3 is V2. Molding in the range of ~ 40. As shown in FIG. 3A, the discharge amounts V1, V2 of the clays 15, 16, 22, 23 can be adjusted by the speeds of the support side plunger 17 and the separation membrane side plunger 18, The V1 / V2 ratio was set to be in the range of 1.5-40.

  Here, when the discharge amount of the ceramic powder filling 15 serving as the support 2 is V1, and the discharge amount of the ceramic powder filling 16 serving as the separation membrane 3 is V2, the V1 / V2 ratio is 1.5 to 40. When the V1 / V2 ratio is less than 1.5, there is a problem of deterioration in permeation performance due to excessive thick film. When the V1 / V2 ratio exceeds 40, the separation membrane is This is because separation of the support causes defects in the separation membrane such as membrane breakage and cracks.

  In addition, the more preferable range of V1 / V2 ratio is 5-25.

  2 (b) and 2 (c), the discharge amount of the ceramic powder clay 15 used as the support 2 is V1, and the separation membrane 31 What is necessary is just to set it so that it may become the same as the range of the said V1 / V2 ratio by making the total of the discharge amount of the clay 22 and the discharge amount of the clay 23 used as the separation membrane 32 into V2.

  The raw material used for the ceramic porous support and separation membrane of the present invention is not particularly specified. For example, alumina, zirconia, titania, silica, cordierite, mullite, etc., or a mixture of two or more of these may be used as appropriate. However, α-alumina is preferable from the viewpoint of corrosion resistance, durability, and heat resistance. Among these, α-alumina is preferable. Fused alumina is preferred.

  Furthermore, the raw materials used for the ceramic porous support and the separation membrane may be different raw materials, but it is better to avoid a combination that reacts with each other to form a compound with deteriorated characteristics, and a difference in shrinkage. Needless to say, it is preferable to combine the same raw materials in consideration of warpage and cracks coming from the same.

(Example 1)
First, in order to obtain the cylindrical ceramic porous body 1 shown in FIG. 1, α-alumina having an average particle diameter of 6 μm as a raw material for the ceramic porous support 2, and as a raw material for the separation membrane 3, Α-alumina having an average particle size of 0.3 to 3.0 μm is used, and the particle size distribution of the ceramic powder for the separation membrane 3 is 10% cumulative from the small diameter side, and the particle size corresponding to 90% cumulative is D10, D90 / D10 ratio is set to D90 when D90 is set, and a binder such as Metroise, a lubricant such as Marrex, and a plasticizer such as ceramisole are added to each as a molding binder, kneaded, and extrusion molding The raw material for was obtained.

  Using the above ceramic powder raw material, the mold 11 for extrusion molding shown in FIG. 3 (a) described above, the clay 16 of the separation membrane 3 of the cylindrical ceramic porous body 1 on the outer core 13 side, A two-layered cylindrical ceramic molded body was produced by extruding the clay 15 of the support 2 from the base 12 on the inner core 14 side. Thereafter, by firing, a cylindrical ceramic porous body 1 having an outer diameter φ of 13 mm, a thickness t of 1.8 mm, and a separation membrane 3 having a thickness t1 of 0.04 to 0.6 mm was produced.

Here, the V1 / V2 ratio of the discharge amount V1 of the ceramic powder serving as the support and the discharge amount V2 of the ceramic powder serving as the separation membrane was set to 15. Here, the support side, the respective plungers 17, 18 of the separation membrane side was adjusted each discharge amount ^V1 = ^{339mm 3 /sec,V2=22.5mm} 3 / sec and becomes like. Further, the length L of the die of the mold 11 is 12 mm, and the clay 16 serving as a separation membrane is supplied to the inner wall in the circumferential direction of the outer core 13 through three channels at equal intervals, and the separation membrane at the entrance of the die 12 is provided. The three discharge ports 19 join and discharge.

  The molded body obtained by the above two-layer extrusion molding was cut to a length of 200 mm, and the ceramic porous body set to have a thickness of 1.8 mm was fired at a temperature of 1400 ° C., The obtained cylindrical ceramic porous body 1 was measured for average pore diameter, maximum pore diameter, porosity, air permeation amount, and bending strength. In addition, the separation membrane 3 was also observed for tears and cracks. In addition, each measuring method is as follows.

  That is, the average particle size and particle size distribution of the ceramic powder were measured by measuring the ceramic powder with a laser diffraction method (Microtrack 9320-X100). %, And a 90% cumulative particle size was D10 and D90, respectively, and a ratio of D90 / D10 was determined.

  The average pore size, maximum pore size, and porosity are measured using a micromeritics (pore sizer-9310 type) based on the mercury intrusion method, and the average pore size, maximum pore size, and porosity. The rate was determined.

  In addition, the air permeation amount was measured using an automatic pore measuring device (Perm Porometer) based on the bubble material method manufactured by Porous Materials, and the air permeation amount at a pressure of 500 kPa was obtained.

  In the measurement of bending strength, a three-point bending test was performed using a product of Aiko Engineering Co., Ltd. (digital load measuring machine 1840) under the conditions of a span of 80 mm and a crosshead speed of 0.5 mm / min. The bending strength was obtained from the coefficient and bending moment.

  Furthermore, each sample was observed with a binocular microscope, and inspected for defects such as cracks and peeling of the separation membrane.

  As a comparative example by a conventional manufacturing method, a support is prepared using α-alumina having an average particle diameter of 6 μm, and a suspension containing α-alumina particles having an average particle diameter of 0.5 μm and a D90 / D10 ratio of 3 is used. The ceramic porous body was obtained by coating once and firing at 1500 ° C. In addition, the thickness of the porous body of the comparative example was 2.0 mm, and the thickness of the separation membrane was 0.03 mm.

The results are shown in Table 1.

  As can be seen from the results in Table 1, in Sample No. 22, which is a comparative example in which the separation membrane was formed by coating, the pore diameter and the permeation performance were good, but cracks were observed in the separation membrane. X.

In the examples of the present invention, no defect of the separation membrane was observed in any of the sample numbers 1 to 21, but the ceramic powder particle size of the separation membrane was 0.3 μm, and the sample number 1 was outside the scope of the present invention. -3, the average pore diameter of the separation membrane is 0.014 to 0.016 μm, and the porosity of the separation membrane is 28.1 to 28.3%. Therefore, the air permeation performance is also 0.77 to 0.86 L / min / min. Since cm ³ and sufficient transmission performance could not be obtained, the overall evaluation was x. In addition, when the ceramic powder particle size of the separation membrane is 3 μm and the sample numbers 19 to 21 outside the range of the present invention are large, the maximum pore size is 0.44 to 0.47 μm, and the separation performance cannot be obtained. X.

  On the other hand, in the case of sample numbers 6, 9, 12, 15, and 18 in which the ceramic powder particle size distribution D90 / D10 ratio of the separation membrane is 3.5 outside the range of the present invention, the sample using any powder particle size is used. In addition, either the maximum pore diameter or the permeation performance could not achieve sufficient performance, and the overall evaluation was x.

  On the other hand, sample numbers 4, 5, 7, and 8 produced under the conditions of the ceramic powder particle size of 0.4 to 2.5 μm and the ceramic powder particle size distribution D90 / D10 ratio of 3 or less of the separation membrane of the embodiment of the present invention. , 10, 11, 13, 14, 16 and 17, good results can be obtained in both the maximum pore diameter and the permeation performance, and no film defects such as peeling and cracks are observed at all. Met.

(Example 2)
Next, in order to obtain the cylindrical ceramic porous body 1 shown in FIG. 1 using the same ceramic powder as in Example 1, the clay 15 serving as the support 2 and the clay 16 serving as the separation membrane 3 are The cylindrical ceramic porous body 1 was produced by changing the ratio V1 / V2 of the discharge amount extruded from the die 12 of the mold 11, and the formed separation membrane 3 was evaluated.

  The shape size of the sample is the same as in Example 1, the particle size of the ceramic powder that is the support 2 is 6 μm, the ceramic powder that is the separation membrane 3 is 1.0 μm, and the D90 / D10 ratio is 3.0, The ratio V1 / V2 of the discharge amount V1 of the ceramic powder filling 15 serving as the support 2 and the discharge amount V2 of the ceramic powder filling 16 serving as the separation membrane 3 is in the range of 1.0 to 45 under seven conditions. A ceramic molded body was obtained by discharging the clays 15 and 16, and was fired at a temperature of 1400 ° C. to produce a cylindrical ceramic porous body 1. In addition, about the discharge amount, with reference to the discharge amount ratio of Example 1, the discharge amount was adjusted by the plungers 17 and 18, respectively, and set so that it might become predetermined V1 / V2 ratio.

  About each said sample, it observed using the binocular microscope whether there was any thickness variation of the separation membrane 3, and a defect of peeling or a crack. Regarding thickness variation, five arbitrary locations of one sample were selected, fractured, measured with a binocular microscope, and expressed as a thickness average value, a maximum value, and a minimum value. Moreover, the thing with peeling and a crack was set to x, and the thing which does not have was evaluated as (circle).

The results are shown in Table 2.

  From Table 2, sample number 100 with a discharge rate ratio V1 / V2 ratio of 1 which is outside the scope of the present invention has no defects such as separation and cracking of the separation membrane, but the average thickness t1 of the separation membrane is 0.5 mm. Therefore, the pressure loss was large and sufficient air permeation performance could not be obtained, and the overall evaluation was x. Further, the discharge amount ratio V1 / V2 was 45 and the sample number 106 outside the scope of the present invention had no problem with the air permeation performance, but both separation membrane separation and cracking occurred, and the overall evaluation was x.

  On the other hand, the sample numbers 101 to 105 of the examples of the present invention having the discharge amount ratio V1 / V2 ratio of 1.5 to 40 have an average film thickness of the separation membrane in the range of 0.05 to 0.5 mm, and The variation was also kept small, and there was no separation membrane separation or crack defect.

  From the above results, the discharge rate ratio V1 / V2 ratio is preferably in the range of 1.5 to 40, and in the range of 5 to 25 in consideration of transmission performance, variations in film thickness, and occurrence of film defects. It turns out that it is more preferable.

  The filter using the ceramic porous body of the present invention is used for filtration, concentration and separation processes in industrial fields such as food, pharmaceuticals, electronics, and bio-industry. As described above, in particular, industrial water / waste water treatment It can be suitably used as a filter for use.

It is a perspective view which shows an example of the ceramic porous body of this invention. (A)-(c) is the partial expanded sectional view of the ceramic porous body of this invention. (A) (b) is sectional drawing of the metal mold | die which shows an example of the manufacturing method of this invention. (A) is sectional drawing which shows the manufacturing method of the conventional ceramic laminated body, (b) is sectional drawing of a ceramic laminated body.

Explanation of symbols

1: cylindrical ceramic porous body 2: support bodies 3, 31, 32: separation membrane 11, 111: mold 12, 112: base 13: outer core 14: inner core 15: filling earth 16, 22, 23: Separation membrane filling 19, 25: Separation membrane outlet 18: Ceramic molded body 115: Electrode filling 116: Separator filling 17, 18, 24, 117: Plunger 118: Green laminate molding body

Claims (6)

A cylindrical ceramic porous body comprising a separation membrane on the surface of a cylindrical support, the separation membrane having a thickness of 0.05 mm to 0.5 mm and an average pore diameter of 0.04 μm to 0.3 μm A cylindrical ceramic porous body comprising a single layer or a plurality of layers of an inorganic porous separation membrane having a maximum pore diameter of 0.4 μm or less and a porosity of 30 to 50%. ^2. The cylindrical ceramic according to claim 1, wherein the thickness is 1.5 to 2.5 mm, the bending strength is 40 MPa or more, and the air permeation amount when pressurized to 500 KPa is 1.0 L / min / cm ² or more. Porous body. A method of manufacturing a cylindrical ceramic porous body comprising a separation membrane on the surface of a cylindrical support, wherein the support is made of a raw material made of ceramic powder having an average particle size of 3.0 μm to 9.0 μm. The separation membrane uses a raw material made of ceramic powder having an average particle diameter of 0.4 μm to 2.5 μm, and forms a cylindrical molded body by simultaneously forming both raw materials by extrusion molding. A method for producing a cylindrical ceramic porous body, wherein the formed body is fired at a temperature of 1200 ° C to 1600 ° C. The ceramic powder constituting the separation membrane has a D90 / D10 ratio of 3 or less, where D10 and D90 are the particle sizes corresponding to 10% cumulative and 90% cumulative from the smaller diameter side of the particle size distribution, respectively. The manufacturing method of the cylindrical ceramic porous body of Claim 3. The extrusion molding has a V1 / V2 ratio in a range of 1.5 to 40, where V1 is a discharge amount of ceramic powder as a support and V2 is a discharge amount of ceramic powder as a separation membrane. The method for producing a cylindrical ceramic porous body according to claim 3 or 4, wherein the method is formed by. A ceramic filter using the ceramic porous body according to claim 1.

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