JP2003146774A - Porous ceramic body and method for producing the same - Google Patents

Abstract

(57) [Summary] [Problem] To produce a ceramic porous body having a high strength which can be used as a road surface pavement material or a seawall construction material, using a mixture of organic matter-containing waste and clay as a main material, and In addition, more micropores are generated inside the ceramic porous body to improve the characteristics as a carrier for microorganisms and an adsorbent for malodorous substances and dyes. SOLUTION: When a mixture D of an organic matter-containing waste A, a clay B and an iron compound C is calcined under a reducing atmosphere or an inert atmosphere, the organic matter in the organic matter-containing waste A is evaporated to dryness and solid carbon content is reduced. a, the clay B is sintered to form a ceramic body b, the iron compound C is removed by heating to form highly reactive iron c, and the fired products E and F are porous. Since the iron compound C becomes iron c having micropores therein by firing, the fired product E becomes a ceramic porous body having excellent adsorption characteristics for adsorbing malodorous substances and dyes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for effectively utilizing waste containing an organic substance, and more particularly to a technique for producing a ceramic porous body by firing a material containing a waste containing an organic substance and clay or the like.

Garbage discharged from homes and restaurants,
For effective use of waste such as sawdust and wood chips produced during lumbering, wood and wood waste contained in construction waste, and sewage sludge containing organic substances, these wastes are fired to produce a ceramic porous body. This is conventionally known.

For example, in Japanese Unexamined Patent Publication No. 9-47795, organic additives such as chaff and wood chips are added to organic waste such as organic sludge, and the mixture is stirred and mixed, and then carbonized to form granular carbides. A device for doing so is described. According to this apparatus, it is said that the organic waste can be carbonized by a single carbonization facility to obtain a porous granular carbonized material having an excellent physical adsorption performance such as activated carbon.

Further, in Japanese Unexamined Patent Publication No. 10-120478, small pieces, granular or powdered raw garbage, wood chips,
Alternatively, waste such as flying powder is mixed with a ceramic base material such as clay to form a kneaded or slurry form, which is formed into a desired shape and then fired to burn off or incinerate the waste inside or outside the ceramic base material. , A porous ceramics using a waste formed by forming a space portion in the burned portion, the volume reduction portion due to ashing, and the like.

The thus-produced porous ceramics are water-holding materials for soil, mitigation materials for mitigating rapid water increase in rivers and swamps, carriers for microorganisms, pesticides, deodorants, etc. It is said that it can be used in various fields such as outer wall materials, flooring materials for agriculture and horticulture, roof tile materials, and road paving materials.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The porous granular charcoal-based material described in Japanese Patent Publication No. 795 is a material obtained by dry-distilling an organic sludge by adding an organic additive, and the organic additive is for the purpose of adjusting ash content in order to improve physical adsorption performance. Then, a fiber-containing substance such as rice husk and wood waste is added as a substance having a large amount of carbon and containing a large amount of components that are easily volatilized at low temperatures. However, since the porous body obtained by dry distillation using such organic sludge as a main material has low strength,
It is difficult to use it for building blocks, road blocks, etc., and it can only be applied to applications as activated carbon. In addition, when it is used for purification of sewage in a river, it is lightweight, so that there is a problem that a facility for holding the porous body such as putting it in a container such as a basket is required in order to prevent it from being washed away.

In this respect, since the porous ceramics described in Japanese Patent Laid-Open No. 10-120478 are composed mainly of organic waste and clay as a ceramic base material, the porous ceramics after firing also have high strength. It is presumed that it can also be used as a building block or road block. However, the size of the pores of the porous ceramics in this case depends on the size of the organic substance mixed as a material. Therefore, generation of smaller pores caused by activation of water vapor as seen in the process for producing a carbide described in JP-A-9-47795 does not occur. Relatively large when used as a water retention or microbial carrier 1
Although pores (micropores) of 10 μm may be used, it is necessary to generate a large number of pores (micropores) of 20 to 1000 Å if the porous material is required to have adsorptivity for adsorbing malodorous substances and dyes. Further, there are disadvantages that a large amount of energy is required for the two firings and that the carbon dioxide component once fixed as an organic matter is released to the atmosphere again by burning.

[0008] The problem to be solved by the present invention is to produce a ceramic porous body having a high strength which can be used as a road surface pavement material, a revetment wall construction material, etc., using a mixture of organic matter-containing waste and clay as a main material. And to improve the characteristics as a carrier of microorganisms and an adsorbent of malodorous substances and pigments by forming more micropores inside the ceramic porous body.

[0009]

Means for Solving the Problems The present inventors have studied the characteristics of the ceramics porous body after firing when various additives are added to the main material in which the organic matter-containing waste and clay are mixed, and as a result, By adding an iron compound to organic waste and clay, the microbial carrier that purifies rivers and wastewater while maintaining the strength that can be used as a building block or road block in the ceramic porous body after firing The present invention has been completed by confirming that it can impart an effective function as the above and effective characteristics as an adsorbent of a malodorous substance or a dye.

That is, the present invention is a porous ceramic body formed by molding and firing a mixture containing organic matter-containing waste, clay and an iron compound. Here, organic matter-containing waste refers to wood waste such as thinned wood, lumber discharged from sawing, wood waste from construction waste, raw garbage discharged from households and restaurants, shochu waste liquid, and coffee slag. Food waste such as, sewage sludge, plastic waste materials, and other waste materials containing organic matter. Clay refers to a naturally occurring or artificially prepared clay containing silica, alumina, calcium oxide, or the like as a waste material from a pottery manufacturing plant. The iron compound refers to iron compounds such as iron oxide and iron hydroxide.

The above-mentioned ceramic porous body is a mixture in which a fluid-like or powder-like organic substance-containing waste, a fluid-like or powder-like clay, a powder-like iron compound and other additives are mixed. It can be manufactured by a manufacturing method including a step, a molding step of molding the mixture after the mixing, and a firing step of firing the molded article.

There are various properties of organic matter-containing wastes, and their components and forms are various, but in order to mix with at least clay and iron compounds, they are in the form of fluid or powder. There is a need. At the time of generation, fluid or powdery particles may be mixed with clay or iron compounds as they are, but wood waste materials, plastic waste materials, etc. have a particle size according to the application of the ceramic porous body, for example, a particle size of about 5 mm. The following powder and granules are made, and the solid waste is crushed to form a fluid and mixed with clay and iron compounds. If the waste contains a large amount of water, dehydration treatment or drying treatment is performed as necessary. In addition to the waste containing the organic matter, it goes without saying that it is possible to use the organic matter that can be used for other purposes and is in a state of not being waste.

Clay serves as a base material for a ceramic porous body after firing. At least SiO ₂ : about 45 to 85%, Al ₂ O ₃ : about 10 to 25%, CaO: about 5% or less, K ₂ O. : It is desirable that it contains about 5% or less,
Naturally produced clay can be used as it is, or artificially adjusted clay containing waste wood from a pottery factory can be used.

The iron compound is added to improve the adsorption characteristics of the ceramic porous body after firing. For example, when iron oxide is used as the iron compound, a part of carbon in the organic substance acts on the oxygen content of the iron oxide in the firing step, and iron having high reactivity appears in the ceramic porous body after firing. The property of adsorbing sulfide contained in sewage can be imparted. When iron hydroxide is used as the iron compound, the hydroxyl group is heated to cause a separation action from iron, so that highly reactive iron appears in the porous ceramic body after firing, and adsorption characteristics can be improved. . Here, iron with high reactivity means iron chloride, iron sulfide,
It has a property of easily reacting with other elements such as iron hydroxide and ferric oxide to be bound to each other, and iron contained in the ceramic porous body after firing adsorbs impurities through these reactions. Although there are other metals having similar properties, the iron compound is most suitable in terms of cost, safety, workability, and availability. For example, as the iron oxide, it is possible to use a scale recovered from the pickling waste liquid, crushed scrap iron, or the like. In addition to the iron compound, a compound containing zinc, magnesium, manganese, etc. can be added as a mineral component for propagating microorganisms.

The types of the organic matter-containing waste, the clay and the iron compound, the components and the blending ratio may be selected according to the desired characteristics of the fired ceramics porous body. For example,
As the mixing ratio, an appropriate ratio is selected from the range of 5 to 50 parts by weight of the organic matter-containing waste as a dry weight and 5 to 100 parts by weight of the iron compound with respect to 100 parts by weight of clay. Among these, organic substance-containing wastes having various properties are randomly generated, and therefore, it may be used by selecting from the wastes stored in advance. The firing temperature in the firing step is selected from the range of 600 to 1300 ° C.

In the firing step, when a mixture containing organic matter-containing waste, clay and an iron compound is fired in a reducing atmosphere, the space within the carbide produced by the carbon contained in the waste and the volume due to carbonization The space portion generated between the clay portion and the clay portion becomes micropores (pores of 1 to 10 μm) effective as a microorganism carrier together with water retention. In addition, the portion where the iron compound is reduced and the iron and oxygen or the hydroxyl group is bonded becomes a void and becomes a micropore (a pore of 20 to 1000 Å). The ceramic porous body has an excellent function as a carrier and an excellent adsorption property for malodorous substances, heavy metals, pigments and the like.

When the mixture containing the organic matter-containing waste, the clay and the iron compound is fired in an inert atmosphere, as in the case of firing in a reducing atmosphere, the carbon content in the carbide formed by the carbon contained in the waste is reduced. The space portion and the space portion generated between the clay portion due to the reduction in volume due to carbonization serve as water retention and effective micropores as a microorganism carrier. In addition, the porous body having these pores is a ceramic porous body which is excellent in water retention and functions as a carrier for microorganisms and is excellent in adsorption characteristics of malodorous substances, heavy metals, pigments and the like.

When a mixture containing organic matter-containing waste, clay and an iron compound is fired in an oxidizing atmosphere or a neutral atmosphere, a part of the organic matter-containing waste is burned to form a space. The space becomes a micropore that is effective as a microorganism carrier together with water retention. When iron oxide is used as the iron compound, the carbon contained in the organic substance binds to oxygen in the iron oxide to form highly reactive iron, and when iron hydroxide is used as the iron compound, the hydroxyl group is heated. It separates from iron and becomes highly reactive iron. Oxygen or hydroxyl groups bound to iron become voids to form micropores, and together with the micropores described above become a porous body having fine pores, and a ceramic porous body having excellent adsorption characteristics for malodorous substances, heavy metals, pigments, etc. Becomes

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram schematically showing a process for producing a ceramic porous body according to the present invention. FIG. 1 (a) shows a case where the firing atmosphere is a reducing atmosphere or an inert atmosphere ( b) shows the case where the firing atmosphere is an oxidizing atmosphere or a neutral atmosphere.

In FIG. 1 (a), when a mixture D of organic matter-containing waste A, clay B and iron compound C is fired in a reducing atmosphere or an inert atmosphere, organic matter in the organic matter-containing waste A is Is dried to be a solid carbon content a, the clay B is sintered to be a ceramic body b, and the iron compound C is reduced by heating to become highly reactive iron c.

Since the organic matter-containing waste A is carbonized by firing, the volume is reduced, and a gap G is formed between the carbonized organic matter a after firing and the ceramic body b. Since many voids G are generated in the fired product E after firing, the fired product E becomes a porous body. Since the clay B becomes a sintered body by firing, the fired product E has high strength and can be used as a building block or a road block. Since the iron compound C becomes iron c having micropores inside after being reduced by heating, the fired product E becomes a porous ceramic body having excellent adsorption characteristics for adsorbing malodorous substances and dyes.

In FIG. 1 (b), when a mixture D of organic matter-containing waste A, clay B, and iron compound C is fired in an oxidizing atmosphere or a neutral atmosphere, the organic matter in organic matter-containing waste A is Is ashed into a space H, and the clay B is sintered into a ceramic body b. The iron compound C undergoes a reducing action due to the combustion of carbon or hydrogen in the organic matter or clay by heating, and becomes iron c having micropores inside after the compound is removed by the reaction.

Since the clay B becomes a sintered body by firing, the fired product F has high strength and can be used as a building block or a road block. Since a large number of spaces H are generated in the fired product F, and the iron compound C becomes the iron c having the micropores as described above, the fired product F becomes a porous ceramic body having excellent adsorption properties.

[0024]

[Examples] Materials having the formulations and treatments shown in Table 1 were fired under the conditions shown in Table 2 to obtain fired products. Table 3 shows the characteristics of the fired product.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3] Note) Adsorption amount of methylene blue is JIS K1474
According to the methylene blue adsorption performance test among the activated carbon test methods. The numerical values in the table are the adsorption amount after 24 hours.

As can be seen from Table 3, by adding the iron compound to the organic matter-containing waste and the clay, the adsorption of methylene blue on the ceramic porous body after firing was compared with the conventional method in which the iron compound was not added. Performance improves.

[0029]

EFFECTS OF THE INVENTION An organic compound-containing waste in the form of fluid or powder and a clay in the form of fluid or powder are mixed with an iron compound such as iron oxide or iron hydroxide, and the mixture is molded. By adding an iron compound as a material, the ceramic porous body obtained by firing becomes an iron having a large number of pores inside due to the reduction of this iron compound at the time of firing, and has an adsorption property of adsorbing malodorous substances and pigments. It becomes an excellent ceramic porous body.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a process for producing a ceramic porous body according to the present invention. In FIG. 1, (a) shows a firing atmosphere in a reducing atmosphere or an inert atmosphere, and (b) shows a firing atmosphere. Indicates the case of an oxidizing atmosphere or a neutral atmosphere.

[Explanation of symbols]

A Organic matter-containing waste B clay C iron compound D mixture E, F fired products G void H space a Solid carbon content b Ceramics body c iron

Continued front page    (72) Inventor Tetsuo Nakamura             Kumamoto Prefecture Kumamoto City Higashimachi 3-chome 11-38 Kumamoto Prefecture             Industrial Technology Center (72) Inventor Takanashi Takanashi             Kumamoto Prefecture Kumamoto City Higashimachi 3-chome 11-38 Kumamoto Prefecture             Industrial Technology Center (72) Inventor Chohachiro Nagasawa             1-1-1, Higashi 1-1-chome, Tsukuba City, Ibaraki Prefecture             AIST, Tsukuba Center             Within (72) Inventor Hiroyuki Umehara             1-1-1, Higashi 1-1-chome, Tsukuba City, Ibaraki Prefecture             AIST, Tsukuba Center             Within (72) Inventor Shunichi Shinagawa             1-1-1, Higashi 1-1-chome, Tsukuba City, Ibaraki Prefecture             AIST, Tsukuba Center             Within (72) Inventor, Maruko Ito             2 174 Shimomachi, Otsu Town, Kikuchi District, Kumamoto Prefecture (72) Inventor Hirofumi Ito             2 174 Shimomachi, Otsu Town, Kikuchi District, Kumamoto Prefecture F-term (reference) 4D003 EA24 EA38                 4G019 JA01 JA05 KA01 KA02                 4G066 AA27A AA61B AA63A AC07D                       BA23 BA36 CA02 CA10 DA03                       DA08 FA03 FA17 FA22 FA25

Claims (7)

[Claims] 1. A ceramic porous body obtained by molding and firing a mixture containing organic matter-containing waste, clay and an iron compound. 2. The ceramic porous body according to claim 1, wherein the iron compound is iron oxide or iron hydroxide. 3. A mixing step of mixing the organic matter-containing waste in the form of fluid or powder, the clay in the form of fluid or powder, the iron compound in the form of powder and other additives, A method of manufacturing a ceramic porous body, comprising: a forming step of forming a mixture after mixing and a firing step of firing the formed article. 4. The method for producing a ceramic porous body according to claim 3, wherein the iron compound is iron oxide or iron hydroxide. 5. The method for producing a ceramic porous body according to claim 3, wherein the firing atmosphere in the firing step is a reducing atmosphere or an inert atmosphere. 6. The method for producing a ceramic porous body according to claim 3, wherein the firing atmosphere in the firing step is an oxidizing atmosphere or a neutral atmosphere. 7. The method for producing a ceramic porous body according to claim 3, further comprising a drying step of drying a molding material or a molded product before or after the molding step.