JP2009227511A - Inorganic hydrothermally solidified body, method of manufacturing the same and material using hydrothermally solidified body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zeolite hydrothermally solidified body having high air permeability and water permeability and excellent function of deodorization and water cleaning. <P>SOLUTION: The zeolite solidified body is obtained by molding a kneaded material of zeolite powder, an active calcium source and water and subjecting the molded material to water hydrothermally solidification reaction in an autoclave. The quantity of raw material zeolite to be blended is several times to ten times of the quantity of the active calcium source and is set to have ≥0.1 mm average particle diameter. A part of the raw material zeolite and the active calcium source are reacted with each other to produce calcium silicate hydrate and the raw material zeolite and the active calcium source are solidified by the reaction to secure the strength and to form voids running in all direction. The function such as deodorization is kept because the quantity of zeolite is excessive compared to the quantity of the active calcium source and the high porosity is secured by the large particle diameter of the zeolite. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inorganic hydrothermal solidified body having a function such as deodorization, a production method thereof, and an article (article) using the hydrothermal solidified body.

  Zeolite has been attracting attention for a long time as a material for deodorizing materials and humidity control materials. Zeolite is abundant in nature and mines are scattered throughout Japan. The zeolite crystals (or particles) have numerous fine pores (micropores) on the surface and inside, and organic molecules that become the source of odor are collected in these fine pores to exert a deodorizing function. .

  The material of zeolite is generally in a powder state, and when used for some purpose such as deodorization, it is difficult to handle unless it is kept in a plate shape or the like. Therefore, it is necessary to retain (solidify) the plate shape or block shape. As one of the shape-retaining and solidifying means, there is a method in which an organic binder is mixed with zeolite powder, and this method cannot be used in a high-temperature environment, for example, it is collected by exposure to hot air. There is a problem that the foreign matter cannot be removed and reused, or a void is clogged by the binder, and thus the performance such as deodorization is remarkably lowered.

  On the other hand, as a solidification technology for inorganic powders, there has been hydration hardening for a long time. Therefore, in Patent Documents 1 and 2, gypsum and water are added to zeolite to be hydrated and hardened, and this is used as a deodorizing material. The use is described.

In addition, there is a hydrothermal solidification method as a solidification technique for inorganic powder, and this hydrothermal solidification method has an advantage that high strength can be obtained. Zeolite contains a large amount of SiO _2, and hydrothermal solidification reaction is possible. Therefore, in Patent Document 3, hydrothermal solidification reactivity is enhanced by pulverizing zeolite with a particle size of 30 μm or less, It is described that humidity control is ensured by adding an excessive amount of zeolite to the solidification aid so that unreacted components of the zeolite remain even after heat solidification.
JP 2003-259984 A JP 2003-259986 A Japanese Patent No. 2727287

  Patent Documents 1 and 2 are solidified zeolite using gypsum as a binder, but not only the blending ratio of zeolite cannot be increased, but also the problem that high strength cannot be ensured, and odorous air is solidified for deodorization. Since it only touches the surface of the body material, there is a problem that the deodorizing performance naturally has a limit, and it is difficult to say that the function of zeolite is sufficiently extracted.

  In addition, as a method of increasing the contact area with air, for example, a honeycomb structure is also formed. In this case, too, when air comes into contact, it is only zeolite particles present on the surface, and a large amount existing inside. Part of the zeolite is in a state of being stored without exhibiting a function such as deodorization, so it is difficult to say that the value of the zeolite is exhibited.

  On the other hand, the hydrothermal solidified body described in Patent Document 3 has an advantage of excellent strength, and it can be said that the hydrothermal solidified body shows a direction for effectively utilizing zeolite resources. However, it can be said that there is still room for improvement in order to maximize the function of zeolite and increase its commercial value.

  Furthermore, in order to increase the commercial value of the zeolitic hydrothermal solidified body, it is necessary to make the zeolite particles present in the hydrothermal solidified body function for deodorization and the like, but Patent Document 3 obtains high strength. It is speculated that it has a dense structure because it focuses on the fact that the majority of the zeolite particles that make up the hydrothermal solidified body remain stored without performing its function. It is presumed that

  The present invention has been made on the basis of such a current situation, and the point of solidifying a powder such as zeolite using a hydrothermal solidification reaction is consistent with Patent Document 3 and realizes a novel structure. Therefore, it is an object to further increase the commercial value of the hydrothermal solidified body.

  The invention of the present application includes a hydrothermal solidified body as a product, a production method thereof, and a use article of the hydrothermal solidified body. The invention of claim 1 relates to an inorganic hydrothermal solidified body, and this invention provides an active calcium source or an active magnesium source to a powder or granule mainly composed of an Si-containing inorganic material having a large number of fine pores. An inorganic hydrothermal solidified body obtained by adding, mixing, shaping, and hydrothermal synthesis is characterized by a porous structure in which voids through which gas can permeate exist three-dimensionally inside the solid.

  In the invention of the present application, the hydrothermal solid powder or granule shows an aspect of the raw material, but in this case, the particle size of the powder and granule may be substantially constant or different. The thing of a particle size may be mixed. Further, the state in which the powder and the particles are mixed is also encompassed in claim 1.

  The invention of claim 2 is a preferred example of the invention of claim 1, and the invention is characterized in that the main component is zeolite and the porosity is 30 to 75% or more.

  The invention of claim 3 relates to a manufacturing method. That is, the present invention relates to a process for adding a calcium or active magnesium source and water to a powdery or granular raw material zeolite, mixing and shaping, and then hydrothermally synthesizing to form a solidified body. The blending ratio with the source or the active magnesium source is Ca (Mg) /Si=0.1 to 0.8, the average particle size of the zeolite is 0.01 to 6 mm, and the hydrothermal reaction is performed under saturated steam at 100 to 200 ° C. It is characterized by solidification.

  The hydrothermal solidified material according to the present invention can be used for various applications. For example, as described in claim 4, it can be used for air filters or building materials. Alternatively, as described in claim 5, it can be used as a water purification material that adsorbs ions or heavy metal molecules that are liberated in water.

  In the hydrothermal solidified product according to the present invention, calcium silicate hydrate is generated under saturated steam due to the presence of Si and active calcium source or active magnesium source contained in the main component (functional component). The inside has a porous structure (porous structure) in which voids exist three-dimensionally, and the hydrothermal solidified body can pass gas from the front surface to the back surface, so that the high strength characteristic of the hydrothermal solidified body is secured. The entire interior can be used for purposes such as deodorization. In addition, since it is a hydrothermal solidified body and can withstand high temperatures, it can be easily heated and regenerated in the event of clogging due to use, and is therefore economically superior (because of its high porosity, It is also easy to burn out and remove.)

  As described above, the zeolite crystal has a large number (numerous) fine pores that adsorb gas molecules, and the presence of the fine pores exerts a deodorizing function. By using zeolite as the main component (main raw material), the hydrothermal solidified body can retain a high deodorizing function. As a result, when used in a filter as claimed in claim 4, it is possible to obtain a high-quality filter that has a high deodorizing amount per unit area and can be regenerated by exposure to high temperatures.

  In addition, the fine pores (micropores) of zeolite are too small to adsorb water molecules / particles. However, in the present invention, a large amount of voids (mesopores) exist between the crystals / particles of zeolite. It is possible to collect a large amount of moisture in the gap. For this reason, a high humidity control function can also be exhibited. The amount and ratio of micropores and mesopores can be changed by changing production conditions such as the amount and ratio of zeolite and active calcium source, zeolite particle size, molding conditions, hydrothermal reaction conditions (temperature, pressure, time). It can be controlled, and a structure according to the application can be obtained.

  The porosity of the hydrothermal solidified body mainly composed of zeolite is preferably 30 to 75%. If the porosity is lower than 30%, it will be difficult for gas and the like to pass inside, and it will be difficult to fully function. If the porosity exceeds 75%, the amount of zeolite per unit area will be too small and deodorizing The problem that functions such as become low or become brittle appears. However, when it is necessary to pass the fluid at a high speed, the porosity can exceed 75%, and the strength problem can be covered by combining with a reinforcing material.

  As described above, Patent Document 3 focuses on improving the reactivity of hydrothermal solidification (in other words, increasing the strength), and the particle size of zeolite is not preferable when it is 30 μm (0.03 mm) or more. The inventors of this application have studied this point, and have found that a hydrothermal solidified body can be obtained even if the zeolite particles are large. That is, as in claim 3, even if the zeolite has a particle size of about 6 mm, a hydrothermal solidified porous body could be obtained.

  Further, details of the present invention will be described.

(1) Composition / Formulation / Production Method FIG. 1 shows an example of the chemical composition of zeolite, which is from the Aiko Mine in Miyagi Prefecture used in the following examples. Although the composition differs depending on the production area, in any case, silica accounts for the majority, and silica contributes to the hydrothermal solidification reaction.

  As shown in FIG. 2, the production of the solidified zeolite using natural zeolite is performed by mining the raw zeolite stone, crushing the raw stone into an appropriate size (for example, gravel), and further using a grinder such as a ball mill. Adjust the particle size by pulverizing into powder or granular form, adjust the particle size, add pulverized material, auxiliary agent such as solidification aid and water and knead to make an irregular shaped kneaded material. The intermediate is produced by molding into a shape, putting the intermediate in an autoclave to cause a hydrothermal solidification reaction under saturated steam, and drying as necessary to remove moisture.

  The raw material can be calcined at several hundred degrees before pulverization or after pulverization. It is also possible to use artificial zeolite instead of natural products, and it is also possible to use both artificial products and natural products in combination.

  In the present invention, coarse particles can be used as the raw material zeolite. For example, the average particle size can be used up to about 0.01 to 10 mm. For example, when used for a filter for deodorization, a suitable range is 0.1 to 3 mm. When the particle size is smaller than 0.1 mm, the solidified zeolite becomes too dense and the porosity tends to be low. Conversely, when the particle size is larger than 3 mm, the strength is lowered and the entire surface area of the zeolite group is reduced. Therefore, the tendency for functions, such as deodorizing, to become low becomes strong. For example, it is also possible to mix things having different particle sizes so that those having different particle sizes in the range of 0.2 to 3.0 mm are mixed approximately evenly. The blending amount of the raw material zeolite is preferably 50 to 95 wt% by weight.

  As the solidification aid, active calcium source materials such as slaked lime, Portland cement, quicklime, and glass powder can be used. Due to the presence of the Ca component, calcium silicate hydrate is generated by the hydrothermal solidification reaction and solidifies with high strength. These solidification aids may be of a single type, or a plurality of types may be mixed. The blending ratio of the solidification aid is preferably 5 to 50 wt%. In the present invention, an active calcium source is suitable as the solidification aid, but it is also possible to add an active magnesium source (for example, magnesium oxide) to the active calcium source.

  In any case, it is necessary to reduce the blending amount of the solidification aid to the zeolite and leave unreacted zeolite after solidification. The molar ratio of the zeolite to the solidification aid is preferably in the range of Ca (Mg) /Si=0.1 to 0.8. The amount of water added is preferably 5 to 60 wt%. The water is not necessarily fresh water, and an alkaline solution (for example, one containing an active alkali source such as NaOH) can be used.

  In the present invention, it is possible to pressurize in forming the kneaded product to obtain an intermediate product, but it is also possible to not pressurize at all. As a molding method that does not pressurize, for example, a kneaded product is put in a shallow tray-like container, and an excess part is written off with a spatula to obtain a plate-like intermediate. Pressurization itself should not be avoided because it becomes a porous structure due to hydrothermal solidification reaction. Rather, it may be necessary to press molding from the viewpoint of maintaining the shape constant and facilitating the handling as a product. Many.

  The processing conditions in the autoclave are preferably a temperature of 100 to 220 ° C. and a processing time of about 4 to 12 hours. In the present invention, the reaction temperature does not need to be excessively high, and the hydrothermal solidification reaction can be realized even at 100 ° C. This is also one of the features of the present invention.

(2). Principle of solidification reaction As already described, zeolite has many fine pores at the crystal level, and these countless fine pores contribute to deodorization. Further, zeolite having fine pores remains even after hydrothermal solidification, thereby ensuring high deodorizing properties. And after solidification, there are a large number of voids communicating with each other between the zeolite particles, and the presence of these voids ensures high air permeability (the voids also contribute to the humidity control function).

  FIG. 3 schematically shows how the zeolite (rectangular shape) and the solidification aid (round shape) change with time in the autoclave. That is, Si contained in the zeolite, calcium hydroxide as a solidification aid, and water react with each other hydrothermally to produce calcium silicate hydrate as shown by the needle-like figure, By digesting the uricium silicate hydrate crystallized with the components of the material, the voids reach all four and the bonds between the zeolites are formed, resulting in a porous structure with a high porosity.

  Since zeolite has a higher blending ratio than the active calcium source, a large amount of zeolite that maintains its original properties and properties remains in the porous body. In addition, the reaction proceeds while the zeolite particles are phagocytosed from the surface. However, if the zeolite particles are large, it is assumed that a large number of zeolite particles remain even after the solidification aid has reacted. .

  As can be understood from FIG. 3, the amount of calcium silicate hydrate crystals (number and size) increases (grows) over time (this point is confirmed in the X-ray diffraction pattern). ). The reaction time in the autoclave was preferably about 12 hours.

  The porosity is a ratio of voids to the volume of the solidified body, which can be calculated from the specific gravity (true specific gravity) of the solidified body and the apparent volume. In order to use it as a deodorizing material or water purification material, a certain degree of air permeability and water permeability is required, and for that purpose, a porosity of 30% or more is desirable. In particular, since the liquid has a large flow resistance, it is preferable that the porosity is as large as possible when used as a water purification material or a waste liquid filtering material.

The hydrothermal solidified body of the present invention can obtain a considerable strength. For example, looking at the bending strength, a strength of about 14 MPa can be obtained (naturally, the strength differs depending on the molding conditions).
(3). Example Using raw stones from Aiko Mine, Miyagi Prefecture as a raw material for zeolite, and maintaining the average particle size of 0.2 to 0.7 mm in a dehydrated state, the zeolite powder and slaked lime The amorphous kneaded material was obtained by stirring water with a stirrer. The blending ratio of the materials was 65 wt% for zeolite, 5 wt% for slaked lime, and 30 wt% for water (fresh water).

The kneaded product is put into a round pressure molding machine and pressurized at 3 MPa to form a disk-shaped intermediate body having a diameter of 30 mm and a thickness of 5 mm, as shown in FIG. The intermediate was put in an autoclave and exposed to saturated steam at a temperature of 200 ° C. for 12 hours to cause a hydrothermal solidification reaction, whereby a zeolite solidified product (practical product) was obtained.
[Breathability test]
The solidified body of Example 1 manufactured in this way was first measured for air permeability, and as shown in FIG. 4B, a zeolitic honeycomb structure having a lattice shape and a dense structure inside. (The hydrothermal solidified body has the same outer diameter and thickness as those of the practical product: Comparative Example 1), a commercially available dishwashing sponge shown in FIG. 4C (single-layer structure product: Comparative Example 2)), FIG. 4 (D) The three articles | goods of the cotton-like filter for air cleaners (comparative example 3) shown in 3 were selected and used as a comparative example. In the air permeability test, as shown in FIG. 5 (A), a sample is fixedly arranged inside a cylindrical body, air is blown from one end of the cylindrical body with a pump, and discharged from the other end. The pressure difference between them was read with a differential pressure gauge.

  From the graph of FIG. 5B, the breathability of the product of the present application is superior to the dishwashing sponge (Comparative Example 3), which is inferior to the honeycomb structured product (Comparative Example 2) and the filter for the air cleaner (Comparative Example 3). From this, it can be understood that it has sufficient air permeability for practical use as a deodorizing material.

The flow rate of air passing through the cylinder is V (mm ³ ), the air permeability is μ (mm ² ), the air viscosity is η (1.8 × 10 ⁻⁶ Pa · s), and the cross-sectional area of the product is S. (Mm ² ), where the thickness of the actual product is L (mm) and the pressure difference between both sides of the actual product is ΔP (Pa), the relationship V = μ · 1 / η · S / L · ΔP is established. Therefore, μ = V / (1 · 1 / η · S / L · ΔP). And, it was actually measured at ^{μ = 5.81mm 2 (S = 1cm} 2, L = 10mm, ΔP = 1000Pa). In addition, for example, when used in a deodorizing filter, the flow rate per unit area (air flow rate) is important, but the thickness of this product is set to 1 cm, the cross-sectional area is set to 1 cm ² , and the differential pressure is set to 1000 hPa. The air flow rate V was 1.94 × 10 ⁶ mm ³ / min.

The porosity was measured according to the measurement method of the sintered density / open porosity of “JIS R 1634 Fine Ceramic”. As a result, the apparent density was 4.56 g / cm ³ , the bulk density was 1.54 g / cm ³ , and the open porosity was 66.19%. Porous ceramic article a comparative example shown in FIG. 5 (C) (D) has an apparent density of 3.8 g / cm ³ big bulk density is 2.2 g / cm ^3, also porous ceramic article b of the comparative example apparent density big bulk density is 3.8 g / cm ³ was 2.1 g / cm ^3.

  FIG. 5C shows an example of specific numerical values of the differential pressure between the product of the present application, the honeycomb structure described above, and a commercially available boxed tissue paper. The area is calculated as a diameter of 30 mm. In addition, as for this invention implementation product, A was a thing without a frame or an interior thing, B and D were the things with an outer frame, (C) was a thing with a reinforcement metal-mesh. In addition, commercially available tissue paper in a box is a set of two sheets and is drawn out from the box in a state where the two sheets overlap each other, but in this comparative example, two sheets of the laminate are taken as one unit (thus, strictly, 16 Sheets are stacked.)

  FIG. 5D is a graph comparing the differential pressures between the product of the present application and the comparative example. From this figure (D), it can be understood that the air permeability of the example of the present application is almost equal to that of the tissue paper laminate.

[Deodorization performance test 1]
In FIG. 6, a test of deodorizing performance is performed. That is, in this test, as shown in (A), a sample was put in a sealed container, and the change in concentration of formaldehyde over time was read with a gas concentration meter, and (B) is a graph thereof. The actual product was 30 mm in diameter and 1 gram in weight. As a comparative product, 1 gram obtained by pulverizing a raw zeolite stone into 200 mesh was used.

  In this test, the test product and the comparative product were inspected using one device, and the concentration of formaldehyde at the starting point was slightly different between the test product and the comparative example due to slight differences in conditions. However, it is clearly shown in the graph that the product of the present application exhibits the same deodorizing performance (adsorption performance) as that of the powder even in a state where forced ventilation is not performed. The capacity of the sealed container (desiccator) was 19 liters.

[Deodorization performance test 2]
In FIG. 7, the deodorization performance test is also performed. In this example, a tank, a cylinder, and a pump (or a blower) are connected in a closed circuit, and a sample is placed in the cylinder and the pump is operated to circulate air in one direction. Then, ammonia was injected into the tank, and the change in concentration over time was read with a densitometer. As a comparative example, the case where the zeolite powder is simply left in the pipeline and there is no air circulation is shown. From FIG. 7 (B), it can be understood that the product of the present application has high deodorization performance and high practicality while being a solidified body.

[Deodorization performance test 3]
FIG. 8 also shows the deodorization performance test. In this test, as shown in (A), the sample of the present invention product is fixedly arranged inside the cylindrical body (the outer periphery is sealed), and the pump inlet and outlet are connected to both ends of the cylindrical body. The air tank is interposed in the inflow passage to the cylindrical body, and the inside of the air tank is filled with ammonia gas, and the pump is operated to circulate the air in one direction. It was detected with a gas densitometer how the ammonia concentration changed.

  The result is shown in the graph of FIG. 6, and it can be confirmed from this graph that the ammonia concentration is drastically lowered at the start of operation and the odor is drastically reduced within a few minutes.

  As mentioned above, although embodiment of this invention was described, this invention can be embodied variously besides said each embodiment. For example, the use is not limited to deodorizing materials, but can be used for various purposes such as water purification materials, air purification materials, humidity control materials, building materials such as wall materials, sound absorbing materials, and heat insulating materials. Needless to say, the shape may be set according to the application.

  It is also possible to embed a reinforcing body as necessary. In the present invention, an inorganic material other than zeolite (for example, fly ash) can be used as a functional component. It is also possible to mix zeolite and other functional members.

It is a table | surface which shows a composition of a zeolite. It is the schematic of a manufacturing process. It is a schematic diagram which shows the progress state of hydrothermal solidification reaction. It is an external view of an implementation product and a comparative example. It is a figure which shows the test method and result of ventilation | gas_flowing performance. It is a figure which shows the test method and result of a deodorizing performance. It is a figure which shows the test method and result of a deodorizing performance. It is a figure which shows the test method and result of a deodorizing performance.

Claims (5)

  An inorganic hydrothermal solidified product obtained by adding active calcium source or active magnesium source to a powder or granule mainly composed of Si-containing inorganic material having a large number of fine pores, mixing and shaping, and then hydrothermal synthesis. An inorganic hydrothermal solidified body having a porous structure in which voids through which gas can permeate exist sterically.   The inorganic hydrothermal solidified material according to claim 1, wherein the main component is zeolite and has a porosity of 30 to 75% or more. It is a manufacturing method in which an active calcium source or an active magnesium source and water are added to a powdery or granular raw material zeolite, mixed and molded, and then hydrothermally synthesized to form a solidified body,
The blending ratio of the zeolite to the active calcium source or the active magnesium source is Ca (Mg) /Si=0.1 to 0.8, the average particle size of the zeolite is 0.01 to 6 mm, and saturation is 100 to 200 ° C. A method for producing an inorganic hydrothermal solidified product, characterized by hydrothermal solidification under steam.   The filter for air or the building material which uses the hydrothermal solidification body in any one of Claims 1-3.   The water purification material which uses the hydrothermal solidification body in any one of Claims 1-3, and adsorb | sucks the ion or heavy metal molecule which is free | released in water.

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