JP2007070171A - Natural porous solidified body, and solidifying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To compact a natural porous body having fine pores without destroying the fine pores, and solidifying the same in a short time. <P>SOLUTION: A natural porous body having fine pores such as volcanic ash, allophane, sepiolite, smectite, formite, opaline silica, pearlite and imogolite is blended with a calcium component, a silica component and water, and the blend is subjected to molding and preliminary curing, is thereafter subjected to normal curing such as hot water curing (e.g., hot water curing at 60°C) and autoclave (e.g., holding at 180°C, under 10 atmospheric pressure for 1 hr), thus the natural porous solidified body having fine pores is obtained in a short time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solidified body of a natural porous body such as volcanic ash, allophane, sepiolite, smectite, holmite, opaline silica, pearlite, imogolite, etc., and the natural porous body has fine pores and is in the form of a powder. It is widely used as a gas deodorizing material, a water purification material, a humidity control material, and an absorbent for harmful components. The natural porous body is solidified without breaking fine pores, and is intended to be used more effectively for applications such as building materials, daily life materials, and chemical industry materials.

  Natural porous bodies are often used in the form of powder or granules so far, but there are the following information as a method for solidification. In Japanese Patent Publication No. Hei 8-112405, water-soluble halogen glass fiber, volcanic ash, inorganic lightweight aggregate, etc. are suspended in an aqueous solution of sodium polyacrylate, molded into a predetermined shape, dried and solidified, demolded, and formed as a molded product. In Patent Publication 2000-104353, a foaming agent is added to sepiolite powder, Portland cement, glass cullet, fly ash, and kibushi clay are added and stirred, mixed and kneaded to form a soft mud-like composition having a predetermined shape. After molding and drying, a molded composition is fired at 1100 ° C. to produce a porous sintered body. In Japanese Patent Laid-Open No. 5-280121, a slurry composed of sepiolite, glass fiber, thermoplastic resin and thermosetting resin Is formed into a wet sheet, and an inorganic cloth made of glass cloth is sandwiched between them and dried and solidified. Is obtained by drying and solidifying a paste-like mixture composed of titanium oxide or hydrated oxide and a smectite-based viscosity mineral, and then pulverizing it to form a catalyst carrier, on which a vanadium compound is supported by a wet method, or titanium oxide or A paste-like mixture of a hydrated oxide, a smectite-based viscosity mineral, and a vanadium compound is dried and solidified and then pulverized to produce a catalyst for removing nitrogen oxides. In JP-A-11-89468, an allophane-based clay containing iron is used. In Japanese Patent Publication No. 7-276558, a pet litter composed of a granule of a composition of a mineral and a smectite group clay mineral and a holmite group clay mineral is provided on the outer peripheral surface of a thermoplastic resin pipe. Spray and apply an adhesive containing a flame retardant, and plant inorganic materials such as leech stone and pearlite by electric flocking method. In patent publication 2001-328857, which forms a layer and solidifies, natural minerals with moisture conditioning and self-hardening properties are mixed with aggregates, fibrous materials, peptizers, etc., using opaline silica and smectite as the main raw materials. In Japanese Patent Application Laid-Open No. 9-110551, which is kneaded with water, a method of solidifying a mortar obtained by kneading a hydraulic inorganic material, an ultralight aggregate, and a siliceous admixture is described. As described above, various methods have been tried for solidifying the natural porous body. However, the amount of the solidified body relative to the natural porous body is large, or because an organic substance is used, or Since it was sintered, the fine pores of these natural porous bodies were blocked and the original function could not be fully exhibited.

As an improvement measure, in the present invention, water is added to the natural porous material, calcium component, and silica component, kneaded, molded, pre-cured while sufficiently humidified, and then, for example, main-cured in an autoclave. This makes it possible to produce a solidified body by a hydration reaction while retaining most of the fine pores of the natural porous body.
Patent Publication 8-12405 Patent Publication 2000-104353 Patent Publication 5-280121 Patent Publication No. 8-168640 Patent Publication 11-89468 Patent Publication 7-276558 Patent Publication 2001-328857 Patent Publication 9-110551

  According to the present invention, a solidified body is obtained without destroying the fine structure of an excellent natural porous body.

  According to the method of the present invention, a calcium component, a silica component, and water are blended into a natural porous body, and preliminary curing and main curing are performed, so that the excellent characteristics of the natural porous body are reduced without greatly decreasing. A solidified body is obtained in time. That is, the natural porous body and calcium components such as calcined lime, slaked lime, Portland cement, and shell powder, silica components such as silica powder, silica gel, and coal ash, and water are kneaded, molded into a mold, molded indoors or Store in a constant temperature heating tank in a humidified state for several hours or more (pre-curing), and after it has hardened to the extent that it can be released from the mold, for example, hydrothermal synthesis under conditions of 180 ° C. and 10 atm (autoclave curing) A solidified body having sufficient strength can be obtained without impairing the properties of the porous body. In the case where autoclave curing is not performed, a solidified body composed mainly of natural porous material that maintains a porous state in a short time can be obtained if sufficient moisture is applied and heat curing is performed.

  Conventionally, natural porous bodies are difficult to solidify, for example, in the case of sepiolite, adjusting the particle size of the mined bulk material, removing soil from the soil as a soil conditioner for farmland, filter media, treatment of waste liquid, It is used for purification of water and sewage and fish farms. According to the present invention, the porous material can be easily maintained without breaking the fine pores of the natural porous material, and can be easily molded and solidified in a short time. It is possible to use a porous solid body by molding and solidifying it into an arbitrary shape suitable for the above. Natural porous materials, quicklime, slaked lime, Portland cement, silica stone powder, silica gel, coal ash, etc. are raw materials that can be obtained at a low cost. Coal ash, shells, starfish, etc. are partly disposed of as industrial waste. By effectively using these raw materials, effective materials are provided at low cost in the building material field and the chemical field.

  As the calcium component, calcined lime, slaked lime, Portland cement, and shell powder powder can be used. Quicklime is obtained by baking limestone powder, and slaked lime is obtained by reacting quicklime with water, but all use natural raw materials and are inexpensive and have no problem with the supply amount. Portland cement is also a material that is easily obtained by firing limestone or the like into powder. Shells such as oysters, pearl oysters, scallops, and starfish are disposed of in landfills in Japan. However, when powdered and calcined at a temperature of 800 ° C or higher, they become calcium oxide and should be used for solidification of zeolite. Can do. Effective use of industrial waste.

  Natural porous material is a raw material mainly composed of silica. When mixed with calcium component and water and autoclaved, the silica component and calcium in the natural porous material react to produce hydrate and solidify. . Therefore, the natural porous body is a component necessary for the strength expression of the solidified body, and after solidification, a certain amount or more of the natural porous body remains, and the necessary strength and good humidity control, harmful gas adsorption, catalytic function, etc. In order to develop the characteristics, a natural porous body of 20% by weight or more is necessary, and the calcium component is set to 95% by weight or less in order to blend 5% to 60% by weight. The strength can be improved by adding silica components such as silica fine powder, silica gel, and coal ash that are more reactive than natural porous materials. In this case, when the blending ratio of the silica component is large, the blending ratio of the zeolite is relatively decreased and it becomes difficult to obtain the porous body. Therefore, the blending ratio of the silica component is set to 40% or less.

  The reason why the calcium content is from 5% to 40% by weight is that when it is less than 5% by weight, the strength of the solidified body cannot be obtained sufficiently. This is because the blending ratio of the body is relatively decreased, and humidity control, harmful gas adsorption, and catalytic function are relatively decreased.

  By putting a wire mesh etc. in the porous solidified material and curing it, the effect of preventing the fragments from scattering even when damaged can be expected. Further, by providing a metal, wood or plastic frame around the solidified body, the strength can be increased and handling can be simplified.

  Calcium components such as volcanic ash, allophane, sepiolite, smectite, holmite, opaline silica, pearlite, imogolite and other natural porous bodies and powders of calcined lime, slaked lime, cement and oyster shells baked at 800 ° C (oyster shell powder) The silica components such as silica powder, coal ash, silica gel, etc. are mixed in the proportions shown in Table 1, added with water to make a paste, poured into a cylindrical mold with a diameter of 40 mm and a thickness of 40 mm, deaerated with a vibrator, and moisture from the surface. It was covered with a damp cloth so as not to dry, and pre-cured for one day in a constant temperature bath at 30 ° C. The sample was removed from the mold, cut into a cylindrical sample having a thickness of about 30 mm and a disk sample having a thickness of about 10 mm, and subjected to autoclave curing at 180 ° C. and 10 atm for 1 hour. The compressive strength was measured with a cylindrical sample having a thickness of 30 mm, and the water absorption and bulk density were measured with a disk sample having a thickness of 10 mm. The results are shown in Table 1.

  Like these results, according to the method of the present invention, a solidified body having a sufficiently high water absorption rate and excellent compressive strength can be obtained. In the composition other than the present invention, which was performed as a comparison, it was not cured by preliminary curing, or the water absorption rate was small.

  The same natural porous material as in Example 1 is blended as shown in Table 2, and cured under the curing conditions shown in Table 2. Samples for measuring water absorption and bulk density and samples for measuring compressive strength are prepared, and measurement results Are shown in Table 2. Here, the pre-curing is a paste obtained by kneading the compound and water, pouring into a mold, degassing with a vibrator, covering with a damp cloth so that moisture does not dry from the surface, in a thermostatic bath at 30 ° C. 1 day and night pre-curing was performed. In the warm water curing, after the preliminary curing was completed and the released sample was cut into a predetermined shape, the sample was further placed in a constant humidity heating bath at 60 ° C. and cured for 24 hours. In the same way as for autoclave curing, autoclave curing was performed under the conditions of 180 ° C., 10 atm, and 1 hour. The water absorption, bulk density, and moisture absorption at 90% relative humidity of these samples were measured, and the blending ratios and the measurement results are shown in Table 2.

  From these results, it is understood that although the compressive strength is small in the pre-curing, the strength is increased in the hot water curing, and in the autoclave curing, a large strength is obtained in a short time. Autoclave curing is not limited to the conditions of 180 ° C., 10 atm, and 1 hour, and may be, for example, 120 ° C., 2 atm or 160 ° C., 6 atm, and the holding time is matched to the size and shape of the sample. Conditions that can be cured uniformly can be selected.

According to the present invention, it is possible to solidify without destroying the fine structure of the natural porous body, and it is possible to solidify without impairing the natural porous body's characteristics such as humidity control, deodorization and catalytic function. It was. So far, natural porous materials have been minced and crushed and used as lumps, granules, and powders. However, natural porous bodies can be formed into any shape and solidified. Furthermore, when these solidified materials are kneaded or coated with an antibacterial component or a photocatalyst component, it can be expected that the interior material, the exterior material, the mold for household members, the prevention of dirt, the air cleaning, and the like can be expected. By these methods of the present invention, the effective use of natural porous materials in the chemical industry, the construction field, and daily life parts is further expanded, and there is a great contribution to the industry.

Claims (5)

  It consists of one or more natural porous materials such as volcanic ash, allophane, sepiolite, smectite, holmite, opaline silica, pearlite, imogolite, etc., calcium component, silica component, and retains the fine pores of the natural porous material. A porous solid body characterized by   2. The porous solid body according to claim 1, wherein the natural porous body comprises 20% to 95% by weight, the calcium component comprises 5% to 40% by weight, and the silica component comprises 40% by weight or less.   2. The porous solidified body according to claim 1, wherein the calcium component is one or more of calcined products such as quicklime, slaked lime, Portland cement, shells, cocoons and starfish.   2. The porous solidified body according to claim 1, wherein the silica component is at least one of silica powder, silica gel and coal ash. The method for producing a porous solid body according to claim 1, wherein water is added to the natural porous body, the calcium component, and the silica component, kneaded, molded, pre-cured with sufficient humidification, and then main-cured in an autoclave. .