JPWO2007004424A1 - Method for producing ceramic porous body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a uniform porous body by freely designing a pore size in a wide range of firing conditions.
A base material containing at least 10 wt% or more of a plastic clay from which feldspars containing an alkali component and quartz have been removed by classification, a lime and magnesia component, and an alumina component, relative to 100% of the total weight. The composition is prepared, and the base composition is formed into a predetermined shape and fired at a temperature of 500°C to 1400°C.
[Selection diagram] Figure 1

Description

  The present invention relates to a method for manufacturing a ceramic porous body.

Table 1 shows the composition and firing temperature of the base material in the ceramics (see Non-Patent Document 1). As is apparent here, the main firing is usually performed at 1000° C. or higher. The purpose is to attach importance to the strength of the fired body, and as a result, the structure of the fired body is dense and tends to be composed of many glass phases and crystal phases.
However, unglazed firing at 1000° C. or lower is often intentionally made into a porous sintered body. Its main purpose is water absorption and filterability. That is, the particles and solute of the glass-forming component in the glaze (slurry) are mainly attracted to the pores of μm by the capillary water absorption of the unglazed porous fired body in the glaze process, and the adhesion with the main body and the thickness of the glaze are secured This is because. Although many industrial products that utilize the properties of this unglazed fired body were proposed after the prewar period, examples of those that remain on the market to date include a filter and a base plate for dehydrating a gel cake containing a lot of colloids. Besides, there is a ceramic porous body for the heater. In particular, heaters have been used industrially since 1975 due to the far infrared effect.

In addition, the conventional ceramics are composed of a matrix made of three components obtained by adding feldspar and quartz (silica) to a plastic clay of kaolinite, bauxite, and porphyry clay. Since this base material has good plasticity, various molding methods can be used freely, and it is possible to prepare complicated molded bodies (see Non-Patent Document 2).
On the other hand, as the porous ceramic body, porous white cloud cloud pottery (domite stand pottery) and lime-feldspar pottery pottery (limestone stand pottery) developed in Japan are well known. As shown in Table 2, its base composition is composed of limestone, dolomite, kaolinite clay (kibushi clay), porcelain clay, quartz, and feldspar. , Dolomite, limestone, quartz, kaolinite minerals, sericite, pyrophyllite, and feldspar minerals, and their industrial raw materials often contain quartz.

Ceramic Engineering Handbook Vol.5 Ceramics (1989) Yasuo Shibasaki "From ceramics manufacturing to establishment of water plastic molding technology" Ceramics, 40(2)106-110 (2005)

Therefore, dolomite (dolomite) and limestone stand in pottery CaO (MgO) -SiO 2 _- reaction of feldspars rapidly proceeds at about 1100 ° C., mass of melt formation occurs, softens distortion of the sintered body It was connected. In order to prevent this, addition of an Al ₂ O ₃ component has been attempted, but it is insufficient to obtain a porous body.
Further, the conventional ceramic porous body uses a base material in which a combustible organic substance and an inorganic substance are homogeneously mixed, and a fired body having pores in the voids between the inorganic substance particles of the base substance is generally used. Becomes narrower, and it is difficult to freely design the pore size and manufacture a uniform porous body. Moreover, since the plasticity of the substrate is low, the molding method is also restricted, and the plate-shaped or tile-shaped molding is the mainstream at present.

  Therefore, the present invention aims to provide a method for producing a ceramic porous body which is capable of arbitrarily designing a pore diameter and a pore volume in the range of nano to submicrometer while maintaining heat resistance, and which is also excellent in moldability. It is what

First, in order to suppress softening during firing during ceramic production as much as possible, avoid the presence of feldspars and quartz containing a large amount of alkaline components that tend to form a glass phase (melt) in the constituent materials of the base material, and It is necessary to use constituent materials that generate a monomolecular gas that is the source of the pores of the body at a low temperature.
In other words, the heat resistance improvement measure for reducing the deformation of the molded body exposed to the high temperature gas during firing is the addition of the Al ₂ O ₃ component, and in the production of the ceramic porous body, gas is generated with the thermal decomposition of the constituent materials. Easy to do Al(OH) _{3 and} other Al-containing salts are the main constituent materials, and for other constituent materials, avoiding the inclusion of quartz as much as possible, and blending the base material using various hydroxides and salts that generate gas by thermal decomposition. Is to do.

Therefore, the invention according to claim 1 provides a base composition composed of three components, that is, a plastic clay that has been classified to remove feldspars containing an alkali component and quartz, a lime and magnesia component, and an alumina component, Each component is blended so as to contain at least 10% by weight or more with respect to the total weight of 100%, the base composition is molded into a predetermined shape, and the firing temperature is selected in the range of 500°C to 1400°C. By doing so, it is possible to select any pore diameter and pore volume in the range of nanometer to submicrometer.
The invention according to claim 2 is composed of four components, that is, a plastic clay that has been classified to remove feldspars containing an alkali component and quartz, a lime and magnesia component, an alumina component, and a hydrotalcite. The base composition is prepared so that the above three components are contained in an amount of at least 10% by weight and hydrotalcite is contained in an amount of 5 to 40% by weight based on 100% of the total weight, and the base composition is molded into a predetermined shape. By selecting the firing temperature in the range of 500° C. to 1400° C. and firing, it is possible to select any pore diameter and pore volume in the range of nano to sub-micrometer. is there.
In addition to the object of claim 1 or 2, the invention according to claim 3 adds 3% by weight or less of an alkaline-based sludge modifier of 1000 parts to the base composition in order to obtain a higher quality porous body. To do.

According to the invention described in claims 1 and 2, by firing the molded body with a firing width of 500 to 1400° C. and optionally varying the firing conditions, the pore diameter and the pore diameter can be arbitrarily adjusted in the range of about nano to sub-micrometer. Pore volume can be designed. Further, by adding the alumina component, it is possible to preferably suppress the deformation and distortion of the fired body. Furthermore, since the fine structure is a porous body having a uniform structure, it has excellent thermal shock resistance and is useful in a wide range of industrial fields. In particular, in the invention described in claim 2, since the specific surface area changes linearly with the change of the firing temperature due to the inclusion of hydrotalcite, the pore diameter and the pore volume can be controlled as compared with dolomite-based materials. It will be easy.
According to the invention described in claim 3, in addition to the effect of claim 1 or 2, by addition of alkaline mud modifiers of _{trace, CaO (MgO) -Al 2 O} 3 -SiO 2 composition system solid phase By lowering the reaction initiation temperature, a better quality porous material can be obtained.

The plastic clay used in the present invention is selected from at least one kind selected from kibushi clay, frog eye clay, kaolinite clay, bauxite clay, porcelain clay and various artificial clays. The feldspars and quartz containing the alkali component of this plastic clay and, if necessary, mica are removed using an elutriate or an industrial centrifuge.
On the other hand, the lime and magnesia components may be hydroxides, carbonates or double salts thereof.
The alumina component is preferably one or more selected from porous Al ₂ O ₃ , hydroxides, salts of carbonic acid groups/ammonium groups/hydroxyl groups, and double salts.

Each of these components is contained in an amount of 10% by weight or more to prepare a base composition. Preferably, the plastic clay is 15 to 70% by weight with respect to the base composition, the lime and magnesia components are 15 to 70% by weight with respect to the base composition, and the alumina component is 15 to 70% by weight with respect to the base composition. Select each and mix.
Furthermore, when a base composition is prepared with four components obtained by adding hydrotalcite to the above three components, if the content of hydrotalcite is in the range of 5 to 40% by weight based on the total weight of 100%, the pore size is Also, it is suitable for controlling the pore volume. Further, water glass or the like can be used as the alkaline-type slurry adjusting agent.
The thus-prepared base composition is fired at a firing temperature selected in the range of 500° C. to 1400° C. to fire a ceramic having an arbitrary pore size and pore volume from nano size to sub-micron size and micron meter size. A porous body can be obtained.

  Examples of the present invention will be described below.

《Firing of limestone-based mixed base material》
Mixing the base material with 16% by weight of limestone, 47% by weight of Al(OH) ₃ and 37% by weight of kaolinite clay, and water glass was adjusted to 3.0% by weight with respect to the weight of the basic material of 1000% by weight. Five crucibles (height 70 mm×diameter 81.5 mm) and rod-shaped test bodies (10 cm×diameter 2 cm) were prepared by the method. This was air-dried, placed in an electric furnace, heated to 300° C. as shown in the firing curve in FIG. 1 and held for 1 hour, further heated to a set temperature, and then held for 1 hour, In the form of natural cooling, it was baked at each temperature from 600°C to 1400°C at every 50°C. As a result, the crucible shape of the fired body could be sufficiently maintained up to 1400°C.

《Firing of dolomite-based compounded base》
Mixture of dolomite of 16% by weight, Al(OH) ₃ of 47% by weight and kaolinite clay of 37% by weight was prepared, and water glass was adjusted to 3.0% by weight with respect to 1000 of the substrate weight. The same rod-shaped test body as in Example 1 was molded by the molding method. This was air-dried, then placed in an electric furnace, and fired in the same manner as in Example 1 at 600° C. to 1400° C. at every 50° C. at each temperature.

<<Baking of hydrotalcite compounded base (HT-1)>>
15% by weight of limestone, 37% by weight of Al(OH) ₃ , 10% by weight of hydrotalcite, 18% by weight of frog clay and 20% by weight of kibushi clay, and water glass as the basis weight. The same rod-shaped test body as in Example 1 was molded by the sludge casting molding method in which the amount was adjusted to 3.0% by weight with respect to 1000. This was air-dried, then placed in an electric furnace, and fired in the same manner as in Example 1 at 500° C. to 1400° C. at every 100° C. at each temperature.

<<Baking of hydrotalcite compounded base (HT-2)>>
15% by weight of limestone, 27% by weight of Al(OH) ₃ , 20% by weight of hydrotalcite, 18% by weight of frog clay and 20% by weight of kibushi clay. The same rod-shaped test body as in Example 1 was molded by the sludge casting molding method adjusted to 3.0% by weight with respect to 1000. This was air-dried, placed in an electric furnace, and fired in the same manner as in Example 1 at 500° C. to 1400° C. at every 100° C. at each temperature.

Comparative Example 1
A rod-shaped test body was formed by using 100% by weight of kibushi clay, dried, and then baked in an electric furnace at 400°C, 600°C, 900°C, and 1000°C, respectively.
Comparative example 2
The prepared Hakuun porcelain base material (30% kaolinite clay content, 30% dolomite, 40% feldspar/quartz) was molded, dried, and then unglazed at 700°C. The obtained porous body becomes a μm-order porous body because the interparticle voids of the raw material base material are used.
Comparative Example 3
Alumina catalyst carriers (KHA-24, NKH3-24) prepared by mixing Al(OH) ₃ in 90% by weight or more and kaolinite clay in 10% by weight or less are commercially available. This was baked at 900° C. and 1000° C., respectively.

Hereinafter, the fired bodies obtained in the above examples were evaluated.
<Shrinkage rate and 3-point bending strength>
The firing shrinkage of the limestone-based base fired body of Example 1, the dolomite-based base fired body of Example 2 and the HT-1 base body fired body of Example 3 was analyzed and evaluated.
The three-point bending strengths of the limestone-based green body of Example 1 and the HT-1 green body of Example 3 were measured and evaluated.
Limestone-based green body rod-shaped test body of Example 1 (600 to 1400° C.), dolomite-based base body baked body rod-shaped test body of Example 2 (600 to 1400° C.), and HT-1 base body fired body of Example 3. The firing shrinkage curve of the rod-shaped test body (500 to 1100° C.) is shown in FIG.
3 shows the 3-point bending strength curves of the limestone-based green body (600 to 1400° C.) of Example 1 and the HT-1 green body (500 to 1100° C.) of Example 3. The bending strength is at least 5 MPa or more, and 10 MPa or more at a firing temperature of 800° C. or more. Further, from FIGS. 2 and 3, it can be inferred that there was apparently three-stage solid-phase reaction.

《Water absorption rate》
The water absorption rates of the limestone-based green body of Example 1 and the HT-1 green body of Example 3 were measured and evaluated. The water absorption rate was measured using LIBROR ED-2000 manufactured by Shimadzu Corporation. The measurement was performed according to the following procedure.
Each test body was boiled for 2 hours and then wiped with a towel to measure the water content weight, and then each test body was dried at 110° C. for 3 hours to measure the dry weight. The dry weight was subtracted from the wet weight, divided by the dry weight, and multiplied by 100 to obtain the water absorption. FIG. 4 shows the water absorption curves of the limestone-based green body (600 to 1400° C.) of Example 1 and the HT-1 green body (500 to 1100° C.) of Example 3 thus obtained.
From FIG. 4 as well, a three-step change in the pore volume is recognized. In the range of 500 to 800° C., the constituent basic materials sequentially undergo decomposition reactions, so it can be estimated that the number and volume of pores are increasing due to the increase of the starting point of the generated gas and the expansion of the generated gas.

  The tendency of the water absorption rate and the firing shrinkage rate at 800-900°C to decrease is a decrease in interparticle voids accompanying the initiation of the sintering reaction, and an increase in contact points between particles increases bending strength. In the range of 900 to 1200° C., as the sintering reaction proceeds, the growth of crystal grains and the growth of nanopores proceed to coalesce, so that it is apparently displayed so that the firing shrinkage and the water absorption do not decrease. There is. However, since the three-point bending strength decreases around 1200° C. and the water absorption rate and the firing shrinkage rate tend to increase, one side of the pore coalescence phenomenon due to the progress of the sintering reaction can be detected by these three indexes. The phenomenon in the range of 1300-1400° C. is due to the progress of melting and softening of a part of many crystals.

<<Identification by X-ray powder diffraction>>
The limestone-based green body of Example 1 and the HT-1 green body of Example 3 were identified by X-ray powder diffraction.
The limestone-based base fired body of Example 1 and the HT-1 base body fired body of Example 3 were crushed to obtain a test powder for powder X-ray diffraction. Tables 3 and 4 show the crystal phase transitions of the calcined limestone substrate (600 to 1400°C) and the calcined HT-1 substrate (500 to 1400°C) obtained from the powder X-ray diffraction pattern, respectively.

CaCO ₃ of the constituent materials decomposed at 750° C., (Mg,Ca)CO ₃ at around 700° C., and SiO ₂ mixed in a small amount in the kaolinite clay remained up to 850° C. The other constituent materials were pyrolyzed up to 500°C. It is presumed that a porous structural skeleton is formed by metakaolinite, which is a decomposition product of active porous Al ₂ O ₃ and kaolinite generated by decomposition at 500° C. or lower. Among them, Hydrotalcite progresses to spinel formation. It seems that MgO and CaO to the porous skeleton react with each other to form Gehlenite and Anorthite by skeleton surface reaction. Furthermore, it is considered that the surplus Al ₂ O ₃ component undergoes a phase transition to α-Al ₂ O ₃ at 1100° C. or higher. As a result of this reaction process, the sintering reaction may be suppressed and the porous skeleton may be maintained even at a high temperature of 1000° C. or higher.

<<Measurement of BET specific surface area>>
After crushing the limestone-based green body of Example 1, the dolomite-based green body of Example 2, the HT-1 green body of Example 3, and the HT-2 green body of Example 4, a nitrogen adsorption method is performed. The BET specific surface area was measured by.
A kibushi clay fired body of Comparative Example 1, an alumina catalyst carrier of Comparative Example 3, a limestone base fired body of Example 1, a dolomite base fired body of Example 2, an HT-1 base fired body of Example 3, And the result of having measured the BET specific surface area about the HT-2 base calcination object of Example 4 is shown in FIG.
From this graph, it was shown that the 900° C. fired bodies of Examples 1 to 4 had a specific surface area of 30 m ² /g or more. Therefore, it can be said that each example has a sufficient pore specific surface area as a ceramic filter.
Further, in the HT-1 and HT-2 prepared by mixing hydrotalcite, the graph of the specific surface area is linearly developed from low temperature to high temperature as compared with the dolomite system containing magnesium similarly. This is because dolomite, which is a constituent material of dolomite, starts to decompose at around 700°C, whereas hydrotalcite, which is a constituent material of HT-1 and HT-2, starts to decompose before 500°C. caused by. As a result, the graphs of HT-1 and HT-2 change linearly even when spinel is generated at around 1000°C. From this, it can be said that the addition of hydrotalcite makes it easier to control the specific surface area as compared with dolomite.

<<Relationship between pore volume and pore diameter>>
Further, based on the above data, the limestone-based green body of Example 1, the dolomite-based green body of Example 2, the HT-1 green body of Example 3 and the HT-2 green body of Example 4 were used. A distribution curve showing the relationship between the pore volume and the pore diameter at each firing temperature was obtained.
The limestone-based green body of Example 1, the dolomite-based green body of Example 2, the HT-1 green body of Example 3 and the HT-2 green body of Example 4 were thin at each firing temperature. The pore volume and the pore size distribution curve are shown in FIGS. 6, 7, 8 and 9.
The pore diameter and the pore volume were measured using a Tristar 300 manufactured by Shimadzu Corporation. In the measurement, 0.2 g of the powder was deaerated in vacuum for 12 hours. The pore volume and pore diameter were calculated from the detached side based on the BJH model.

Pore formation and maintenance measures up to high temperature (see FIGS. 6, 7, 8 and 9)
In the present invention, a mixture of kaolinite and Al(OH) ₃ is pyrolyzed at a low temperature by a thermal decomposition method to suppress the formation of a SiO ₂ —Na ₂ O-based glass phase that causes liquid phase sintering as much as possible. It is possible to keep the porous body up to a high temperature by precipitating the sintering progress by precipitating an alkaline earth-containing crystal capable of imparting heat resistance from a low temperature.
The generation of nanopores is a low-temperature pyrolyzate, and after decomposition it appears to precipitate a crystalline phase containing alkaline earth that contributes to the heat resistance improvement by joining the Al-Si-O system centered on kaolinite and alumina. I chose From the results of X-ray diffraction, it is estimated that various crystals containing calcium aluminosilicate were generated near the Al-Si-O-based porous skeleton at 1000°C or lower, and thus the sharpness of the pore size distribution could be maintained up to 900°C. To be done. Furthermore, since hydrotalcite, which requires addition of MgO component and Al ₂ O ₃ component, decomposes, spinel having good heat resistance at low temperature is generated on the surface side of the skeleton pores to maintain the porous skeleton. It can be inferred that the sharpness of the pore size distribution could be maintained up to 1100°C. Furthermore, from the results of measurement of the specific surface area in FIG. 5, it was estimated that up to about 1300° C., the pores forming the porous skeleton became large, but the porous skeleton could be maintained.

For reference, FIGS. 10 to 12 show the relationship between the pore size and the pore diameter of the fired bodies in Comparative Examples 1 to 3, respectively.
In each fired body obtained in Comparative Example 1, the pore size distribution curve on the nm order is as shown in FIG. 10, but the pore volume and the sharpness of the pore distribution curve are also insufficient for use as a filter, and firing The strength of the body (5 MPa or less) is also insufficient for use as a filter.
With the green fired body using dolomite as a base material containing a large amount of pyrolysate as in Comparative Example 2, pores of nm order can be obtained as shown in FIG. 11, but the pore volume is still insufficient. Is.
The catalyst carrier of Comparative Example 3 has insufficient strength, weak compressive strength, is easily crushed, and loses the sharpness of the pore distribution curve as shown in FIG. Porosity is also lost due to the sintering associated with the phase transition to α-Al ₂ O ₃ at 1000°C.

<< Thermal shock test >>
A thermal shock test was carried out on the HT-1 green body fired body of Example 3 and the HT-2 base body fired body of Example 4.
Each of the HT-1 base material and the HT-2 base material was fired at 1200° C., and the crucible thus prepared was heated by a gas burner and then dropped into water, but there was no damage.

《Ink test》
The crucible (color tone: white) fired at each temperature obtained in Example 1 was put into a transparent red ink (Pilot product number: ink-350-R) up to the 6th minute and observed for 15 minutes. The findings at each temperature are shown below.
(1) Baking at 700°C only wets the surface slightly, and moisture is not transferred to the bottom of the hill. Moisture has reached the top of the crucible. After removing the ink, there was a dark, reddish gel-like substance on the inner wall, which could be wiped off with paper. The color tone of the inner wall was white.
(2) Baking at 800° C. gradually spreads to the upper part as moisture appears after ink is added. After about 10 minutes, the portion below the inner liquid surface became apparently pale yellow. It was confirmed that part of the hill was wet. After the ink was removed, the inner wall of the crucible had the same result as at 700° C., but after the dark reddish gel dye was removed, a pale yellow tint was felt on the white pigment background.
(3) After 900° C. firing, the wetness appears on the surface and gradually rises, changing from a part under the water surface to a pale yellow, which also rises to the upper part. After about 14 minutes, it became slightly pinkish. The hill became completely wet and became pale pink. After removing the ink, the dark red dye could be removed from the inner surface of the crucible, but the white pigment background after that became light yellow.
(4) At 1200° C., it takes on a pinkish tint about one minute after the ink is added, and rises above the water surface. The pink reaches the upper part in about 10 minutes, but stops rising at about 5 mm from the top. The remaining top turned pale yellow. The traces of the plateau became an ink color. After removing the ink, the inner surface of the crucible and the fired substrate were pink with the same color tone. FIG. 13 schematically shows the results of these ink tests.

Findings As a result of these experiments, as a particularly dynamic movement, water is permeated and diffused first, followed by fine light yellow dye dispersed in water, and red dye of μm order moves in pores. Is estimated.
On the other hand, since traces on high ground do not get wet up to about 900°C, water does not penetrate up to about 900°C. The migration of water molecules or several water molecules (clusters) was a capillary condensation phenomenon, and then a capillary phenomenon was observed in which fine particles of dye of subμm dispersed in water moved and increased to μm pore size with water.

  The washing of the 1200° C. crucible after the ink test takes a long time when immersed in water, but when the pink crucible was floated on the water surface, it floated for about 12 hours, and only the inner surface became pink. It could be washed by the same procedure about three times. This has found a water-saving type cleaning method. There appeared to be no dye particles on the outside while the level of the inside and outside was the same. If this is used as a filter, it shows the possibility of backwashing.

A base material was prepared by mixing Al(OH) ₃ , frog clay and limestone in a ratio of 6 patterns of 001 to 006 shown in Table 5, and molded into a rod-shaped test body similar to that of Example 1 by a slurry casting molding method. This was dried in air, placed in an electric furnace, and fired at temperatures of 700°C, 900°C, and 1100°C. Table 6 shows the measurement results of the shrinkage rate and the water absorption rate of each fired body, and the results of the thermal shock test.

From Table 6, in terms of shrinkage, all of 001, 002, 005, 006 are below 10% at each temperature (especially 001, 005 is 8% or less at each temperature), and water absorption is 001, 002, 005, 006. Is more than 20% at each temperature, and it is clear that it can be suitably used as a porous body. Regarding 001, 003, 004, and 006, the performance may be lower than the others depending on the firing temperature, but it can be said that the formulation itself can be actually adopted.
As described above, according to the production method of the present invention, it is understood that the desired performance as a porous body can be obtained even when a part of the three components is mixed at 10% by weight.

The porous body for a ceramic filter according to the present invention is a ceramic filter, a heat resistant reaction container, a heat shock resistant ceramics, a lightweight ceramic building material, a humidity controlling building material, a lightweight ceramic, a large lightweight ceramic (sanitary ceramic, a burning appliance, etc.), a lightweight bone. Materials, catalyst carriers for gas reactions, gas diffusion separation membranes, gas separation membranes, backwashable ceramic filters, ion exchange ceramic membranes, microbial filters, medical filters, various filters for food processing, etc. On the other hand, it enables the use of inexpensive manufacturing methods, various shapes, high strength, heat resistance, and chemical resistance.

It is a graph which shows the baking curve of a compounding foundation. It is a graph which shows the firing shrinkage rate curve of each base material. It is a graph which shows the 3-point bending strength curve of each green body. It is a graph which shows the water absorption curve of each green body. It is a graph which shows the BET specific surface area according to each green body. It is a graph which shows the relationship between the pore volume and the pore diameter in each calcination temperature of a limestone base. It is a graph which shows the relationship between the pore volume and the pore diameter in each firing temperature of the dolomite base material. It is a graph which shows the relationship between the pore volume and the pore diameter at each firing temperature of the HT-1 substrate. It is a graph which shows the relationship between the pore volume and the pore diameter at each firing temperature of the HT-2 substrate. It is a graph which shows the relationship between the pore volume and pore diameter of the porous Kibushi clay porous body. It is a graph which shows the relationship between the pore volume and pore diameter of a Mizuno pottery clay white cloud pottery calcination body (700 degreeC baking). It is a graph which shows the relationship between the pore volume and the pore diameter of the catalyst support (NKH3-24) obtained by mixing and firing Al(OH) ₃ and kaolinite clay. It is explanatory drawing which shows the transparent red ink input test to the baked body (crucible) of a limestone type compounding base material.

Claims (3)

  A base composition consisting of three components, a plastic clay that has been classified to remove feldspars containing an alkali component and quartz, a lime and magnesia component, and an alumina component, each component being 100% by weight of the total By blending so as to contain at least 10% by weight or more, molding the base composition into a predetermined shape, and by firing at a firing temperature selected in the range of 500°C to 1400°C, the range of nano to submicrometer is obtained. A method for producing a ceramic porous body, wherein any pore diameter and pore volume can be selected by.   A plastic composition from which feldspars and quartz containing an alkali component have been removed by classification, a lime and magnesia component, an alumina component, and hydrotalcite, and a base composition consisting of 4 components is used with respect to the total weight of 100%. The above three components are mixed so that each of them is at least 10% by weight or more and hydrotalcite is contained at 5 to 40% by weight respectively, and the base composition is molded into a predetermined shape in the range of 500 to 1400°C. A method for producing a ceramic porous body, which is capable of selecting an arbitrary pore diameter and pore volume in the range of nano to submicrometer by selecting a firing temperature and firing. The method for producing a ceramic porous body according to claim 1 or 2, wherein an alkaline sludge modifier of 3/1000% by weight or less is added to the base composition.

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