JP4460916B2 - Ceramic sintered body having pores of binary structure and manufacturing method thereof - Google Patents

Description

  In the present invention, a unique macropore of diatomaceous earth is artificially connected to a pore of a millimeter-sized tunnel structure, such as a refractory heat insulating material, a water purification material, a humidity control material and a VOC adsorbing material. It has a new dual pore structure and can be used for various applications.

  Many techniques for producing porous ceramics are known, but the respective production methods are known depending on the size and structure of the pores.

  The first technique is a porous body having a “lattice structure”, in which a ceramic composition is injected and filled into pores of a urethane foam resin, and then the resin component is decomposed and molded and fired and sintered. The pore size is large and is widely used as a fireproof filter material when aluminum is dissolved.

  The second technique is an “aggregate type” porous body, which is sintered with pores of the aggregate of coarse particles in the composition as pores, and is produced as a water-permeable pavement plate or a sound absorbing plate.

  The third technology is known as “closed-cell” foam glass, and the technology of Corning in the United States has been known for a long time.

  The fourth technique, which was invented by the present inventor as Japanese Patent Laid-Open No. 2002-47075, uses a characteristic foaming phenomenon during heating of ductile cast iron slag, and Japanese Patent No. 3216034 discloses a raw material such as clay that shrinks during firing. There is a technique for producing water-retaining ceramics in which fine crevices are generated during firing from a composition in which slags that expand in volume during firing are mixed.

  According to the fifth technique, hydrogen produced by adding alkaline solution to metal aluminum according to Japanese Patent Laid-Open Nos. 10-182262 and 11-92211 by the present inventor is formed in a water-containing composition, and a foam is formed and fired. There is ceramic manufacturing technology for sintered continuous through-holes.

  As described above, many conventional technologies are known, but the present invention has macropores that are unique to natural resources in the fourth and fifth conventional technologies possessed by the inventor, and is used as a refractory heat insulating material or filter material. It is a new technology that has developed a product that can be used for various purposes by coexisting the characteristic pore structure of the widely used raw material with the artificially large pores of the tunnel structure.

  The first problem is that diatomaceous earth begins to shrink when it exceeds 1000 ° C during firing and sintering, and shrinkage occurs when a large product is made. It is restricted to a small block shape. The main object of the present invention is a sintered body having a large size, and cast iron slag starting to expand from 900 ° C., particularly ductile cast iron slag, was selected as a suitable one in order to prevent fired sinter.

  The second problem is the control of the size and shape of the pores. As shown in Japanese Patent No. 2899954, slag particles are individually expanded and welded to generate pores, and can be controlled by the particle size and shape of the slag particles. Further, as disclosed in JP-A-2002-4705, in claim 2, the slag particles are oriented and aligned in the extrusion direction by being extruded into a cylindrical shape by a vacuum kneader, and the density is further increased by roller rolling. As a result, the pores and pores of the product became a characteristic of a flat tunnel structure, but the product made by this method is limited to a bulk specific gravity of 0.5 g / cc, and has a large surface area and a high porosity. The target product required requires a method of firing and sintering after molding a porous body under predesigned conditions as shown in claim 3. This method is the use of hydrogen by oxidation of aluminum in the same way as the production technology of ALC, and it can be adjusted by the viscosity of the sludge and the mixing ratio of aluminum and alkali solution, but the porous fabric with a porosity exceeding 80% is extremely The strength is weak and handling is difficult. As means for solving these problems, the present invention has been solved by a method in which a paper mold according to Japanese Patent Application Laid-Open No. 2000-119066 filed by the present inventor is molded and fired and incinerated as it is.

  According to the fourth aspect of the present invention, bubbles are encapsulated in the molded body by a foaming agent, the porosity can be controlled by the amount of foaming agent added, and a cured body is made by cement.

  Furthermore, when diatomaceous earth is fired, amorphous silica is transferred to cristobalite, and cristobalite has nanometer-sized micropores, as is known in barleystone among quartz minerals, There is a possibility that product applications can be expanded in fields such as gas body adsorption.

  In addition, in the manufacturing method according to claims 2, 3, and 4, the blending ratio of diatomaceous earth and the ratio of expanded slag are ranges selected according to the shape and size of the target product, respectively, and clay extrudes a large product. In this case, at least 20% or more is essential as the molding condition. However, in the foam molding according to claim 3 and 4, cement is used without using clay because of the strength of the dried foam and drying shrinkage. In some cases, the method of curing with is preferable.

  As in the physical property evaluation in the embodiments, the present invention is a novel technology that can provide a product that can cope with a versatile required function for energy saving and environmental improvement at low cost.

  The present invention utilizes the pore characteristics of “diatomaceous earth” as a natural resource, so that heat-expandable slag, etc. has been used to improve the generation of shrinkage cracks during heating, which has been regarded as a drawback in the production of ceramics using these as raw materials. In the following, an example of the embodiment will be described. The tunnel-type through-holes having a large size corresponding to the function required by the product coexist.

  The diatomaceous earth that is the main raw material of the present invention does not need to separate and refine clay minerals (Monmo Solonite), quartz, feldspar, etc. that are conventionally used in refractory bricks, filter media, etc. The mixture ratio is adjusted after recognizing these contents, and further, when the moisture content is about 40% in the natural dry state, the mixture is mixed and kneaded while recognizing the moisture content. It is used by an economical production system that removes the coarse particles.

  Slags that exhibit expansibility during heating are those that are discharged in a non-quality state, but show slight expansion due to crystallization from 800 ° C to 850 ° C. Due to the foaming caused by the crystallization expansion of the water tank at 800 ° C to 850 ° C and the continuous decomposition of manganese sulfide, the effect is much greater in a small amount, and the particle size is 0.25 mm to 1.0 depending on the pore size of the target product Select and use within the range up to mm.

  The aluminum metal used for producing the foamed molded product according to claim 3 may be aluminum powder used for ALC, etc., but aluminum containing 20% to 30% of metal aluminum generated when remelting aluminum cans, etc. Dross has not yet been effectively used as waste and can be used.

  Alkaline components for generating hydrogen are mixed with caustic soda and sodium carbonate as aqueous solutions with a pH of 12 or more, and the reaction between slag and these alkalis is known as slag alkali cement (SAC), which rapidly hardens and hardens. Since the oxidation heat generation of aluminum and these reactions proceed simultaneously, the foam is cured in a very short time, which is suitable for production conditions with high productivity.

  Foam molded products with a bulk specific gravity of 0.5 g / cc or less are very weak, and as such, they are easily disintegrated during transportation on the production line conveyor or kiln firing. With the soft mud composition poured into the paper mold of the product, foam curing and drying / curing treatment are performed, and the product is placed in a roller hearth kiln and baked. The paper contains kaolinite or calcareous minerals with high fire resistance, and is fired while adhering to the bottom of the compact to prevent welding of the roller hearth kiln ceramic roller. Up to this is effective for shape retention.

  A fourth aspect of the present invention is a method for forming a preform mud, which is known as a method for producing cellular concrete. Bubbles are a known method for producing concrete in a molded body. Although the bubble is a spherical balloon of about 0.1 mm to 0.2 mm in the molded body, the spherical pores are deformed by the foaming of the slag in the firing process to form the connected pores and meet the purpose of the present invention. Is.

  The product manufactured according to the present invention is applied to a multipurpose functional product, and the product manufactured according to claims 2 and 3 will be described.

  Large fireproof insulation board, large interior tile for building

1. Raw material mixing ratio (weight ratio in terms of dry matter)

2. Manufacturing method Mixing and kneading the above-mentioned composition to a moisture content of 20% ± 1% using a mix muller to make a plastic state clay, using a vacuum kneader, the diameter (outer diameter) 350mmφ, thickness 30mm Extruded into a cylindrical shape, cut into a cylinder length of 500 mm, unfolded to form a flat plate with a width of about 900 mm, a length of 500 mm, and a thickness of 30 mm, and then rolled to a thickness of 10 mm using a roller rolling facility Roller hearth with a dough board of 1200mm length x 10mm thickness treated in a far-infrared irradiation space with a wavelength of 5μm to 20μm for about 5 minutes, and further with a hot air dryer at a temperature of 180 ° C to 200 ° C to a moisture content of 2% or less The product was fired at 1000 ° C. using a kiln to obtain a product having a thickness of 25 mm.

3. Product properties

4). Evaluation Although it is a grade of B2-B5 shown in the JIS standard as a fireproof heat-insulating brick, the reheat shrinkage rate is zero and the bending strength as a plate-like material can be sufficiently satisfied. In addition, the porosity is over 70%, the water retention is high, and the moisture absorption and desorption rate between 45% and 90% of the plate adsorbed with the chemical moisture absorbent (HgCl ₂ ) aqueous solution is 6% over charcoal. -8%.
Furthermore, the bent pore of the tunnel structure is a very effective structure as a sound absorbing material, and high performance is expected.

  Low density porous material

1. Raw material mixing ratio (dry matter weight ratio)

2. Manufacturing process 1) Alkaline water adjusted to pH 12.5 with caustic soda is added to the above composition 1.5 times by weight, and 0.02% of high molecular weight polyethylene oxide is added to the composition weight to make a soft mud state with high viscosity 1 When stirred with a high-speed stirrer for 5 minutes, the volume expands to about 2 times and fills in a 300 × 300 × 100 mm paper mold prepared in advance with vibration.
2) When placed in a foam curing room adjusted to a temperature of 50 ° C to 60 ° C in a paper mold and placed for 30 minutes or more, the amount of heat generated by self-heating is also added, resulting in a molded product with a moisture content of about 30%.
3) Further, dehydration drying is performed in a hot air dryer at a temperature of 100 ° C to 150 ° C, and the paper mold is filled into a roller hearth kiln and baked at 1100 ° C to sinter 300 x 300 x 50 mm. Got the body.

本多孔体は濾過材或いは水質改良材として大量に需要のある分野であるが、物性評価の数値として吸音特性を示したものである。 3. Product properties

Although this porous body is a field that is in great demand as a filter material or a water quality improving material, it shows a sound absorption characteristic as a numerical value for evaluating physical properties.

4). Evaluation ALC products sold under trade names such as Hebel and Sipolex as cement-based porous materials used as building materials and sound-absorbing materials are equivalent in bulk specific gravity, but in terms of compressive strength About 1/3 of this product.
Moreover, the thermal conductivity is extremely low, and the porous ceramic product has characteristics superior to those of the market product. Furthermore, it has a fire resistance of 1200 degrees or more and is expected as a high temperature exhaust filter material.

Claims (4)

A ceramic sintered body with dual-structure pores in which macropores derived from diatomite and artificially created millimeter-size tunnel structure pores are interconnected, and sintered to produce pores artificially material to expand the volume during sintering is cast iron slag, ceramic sintered bodies having a pore dual structure. 20% to 60% diatomaceous earth, iron slag 1 0% to 60%, the composition range of clays 20% to 30% by weight ratio were mixed and kneaded into a plastic state of the moisture content of 15% to 25%, a vacuum clay After extruding into a cylindrical shape using a kneader, cutting and developing to form a plate, compression molding to a predetermined thickness by roller rolling, heating in a far-infrared irradiation zone, and a moisture content of 3 with a hot air dryer The method for producing a ceramic sintered body having a porous structure having a binary structure according to claim 1, wherein a material having a porosity of% or less is charged into a roller hearth kiln and fired in a temperature range of 950 ° C. to 1200 ° C. 50% to 75% diatomaceous earth, iron slag 2 0% to 30%, aluminum powder or aluminum as containing 0.2% to 1.0% as a metallic aluminum content in the composition in a weight ratio ranging from 5% to 20% clay or cement Add dross, add alkaline aqueous solution adjusted to pH 12 or higher with caustic soda or sodium carbonate to make it soft mud, inject and fill into the mold of the specified size, and put the foamed in the mold into the roller hearth kiln. The method for producing a ceramic sintered body having pores having a binary structure according to claim 1, wherein the ceramic sintered body is fired in a temperature range of 950 ° C to 1200 ° C. A mud that contains a large amount of bubbles by adding 0.1% to 0.3% of a polymer foaming agent to a weight ratio composition of diatomaceous earth 60% to 70%, cast iron slag 10% to 20%, cement 10% to 20% After that, a thick mud with a viscosity increased by adding 0.01% to 0.03% of polyethylene oxide is poured into a paper mold, dried and cured, and fired at a temperature in the range of 950 ° C to 1200 ° C. A method for producing a ceramic sintered body having pores having a binary structure according to claim 1.