JP2024058740A - Air diffuser and its manufacturing method - Google Patents

Abstract

[Problem] To provide an air diffuser that can be easily manufactured using inexpensive raw materials, and a manufacturing method thereof. [Solution] The air diffuser plate 2 is made of a porous body containing combustion ash and a binder, and has a pair of surfaces located at different positions from each other, receiving gas in liquid with one surface and emitting fine bubbles from the other surface. The binder may be clay. The ratio of combustion ash in the raw material of the air diffuser plate 2 may be 50 wt% or more, and the ratio of clay may be 50 wt% or less. The calcium and iron contained in the combustion ash may each be 5% wt% or less. [Selected Figure] Figure 2

Description

The present invention relates to an air diffuser and its manufacturing method.

Air diffuser plates are known that receive gas from the outside and release fine air bubbles into liquid. Air diffuser plates are used in a variety of fields, for example, in neutralizing concrete wastewater and aeration at fish farms. Ceramic air diffuser plates are widely used. Patent Document 1 discloses an air diffuser plate in which multiple air diffuser holes are formed in a thin metal plate.

JP 2010-158631 A

The diffuser plate in Patent Document 1 is manufactured by processing a thin metal plate, which means that it is labor-intensive to manufacture and the manufacturing costs are high; similar problems exist with ceramic diffuser plates. Diffuser plates are consumables and need to be replaced periodically to maintain their performance, so there is a demand for them to be available at the lowest possible cost. Furthermore, these problems are not limited to diffuser plates, but also exist with diffusers of other shapes, such as diffuser cylinders.

The present invention was made against this background, and aims to provide an air diffuser that can be easily manufactured using inexpensive raw materials, and a manufacturing method thereof.

In order to achieve the above object, the air diffuser according to the present invention comprises:
It is composed of a porous body containing combustion ash and a binder, and has a pair of surfaces located at different positions from each other. When immersed in liquid, it receives gas on one surface and releases fine bubbles from the other surface.

The present invention provides an air diffuser that can be easily manufactured using inexpensive raw materials, and a manufacturing method thereof.

FIG. 2 is a front view showing a configuration of an air diffusing plate according to an embodiment of the present invention. 2 is a cross-sectional view of the air diffuser plate of FIG. 1 taken along line AA. 4 is a flowchart showing a flow of a method for manufacturing an air diffuser plate according to an embodiment of the present invention. 3 is a flowchart showing the flow of an assembly method for an air diffusion device according to an embodiment of the present invention. FIG. 2 is a photograph of the appearance of a test specimen sintered at a sintering temperature of 1000° C. in Example 1. FIG. 2 is a photograph of the appearance of a test specimen sintered at a sintering temperature of 1100° C. in Example 1. FIG. 2 is a photograph of the appearance of a test specimen sintered at a sintering temperature of 1200° C. in Example 1. FIG. 13 is a diagram showing the blending amounts of raw materials of test specimens in Example 2. FIG. 1 is a photograph of the appearance of a test specimen after firing in Example 2. FIG. 1 is a diagram showing the component ratios of clay, combustion ash A, and combustion ash B in Example 3. FIG. 13 is a photograph of the appearance of a test specimen after firing in Example 3. FIG. 13 is a photograph showing a process of producing a test specimen by a slurry molding method in Example 4. FIG. 13 is a photograph of a test specimen being produced by the slice molding method in Example 5. FIG. 13 is a diagram showing the results of a performance test of the air diffusing plate in Example 6. FIG. 13 is a schematic diagram showing the configuration of a test device for pH measurement in Example 6. 1 is a graph showing the change in pH value over time in Example 7.

The following describes in detail an air diffuser and a manufacturing method thereof according to an embodiment of the present invention with reference to the drawings. In each drawing, the same or equivalent parts are given the same reference numerals. In the embodiment, an air diffuser plate is used as an example of an air diffuser.

The air diffuser 1 is a device that is installed in a liquid, receives compressed gas, and generates fine bubbles in the liquid. The fine bubbles emitted by the air diffuser 1 are, for example, fine bubbles with a bubble diameter of 2.5 mm or less, and are formed of any gas, for example, air, oxygen, or carbon dioxide, depending on the application. The liquid in which the air diffuser 1 is installed is any liquid, for example, water. The air diffuser 1 can be used, for example, for neutralizing alkaline effluent such as concrete wastewater, for supplying carbon dioxide gas for the growth of aquatic plants such as algae, and for supplying oxygen or air for land-based aquaculture and sewage treatment. The following describes an example in which air is used as the gas and water is used as the liquid.

As shown in FIG. 1, the air diffusion device 1 comprises an air diffusion plate 2 that receives compressed air and generates fine bubbles that are released into water, and a case 3 that is attached to cover part of the air diffusion plate 2 and supplies compressed air to the air diffusion plate 2. The air diffusion plate 2 has a pair of opposing surfaces, receives air on one surface (back surface) and releases fine bubbles containing air from the other surface (front surface). The air diffusion plate 2 is formed of a porous body with many internal pores, and converts the compressed air that flows in from one surface into fine bubbles by passing it through the many pores, and discharges the fine bubbles from the other surface.

The diffuser plate 2 is, for example, disk-shaped. Compared to diffuser plates of other shapes, for example, rectangular shapes, the disk-shaped diffuser plate has no corners and is less likely to break, and high-pressure air does not concentrate locally, so it is easy to generate uniform fine bubbles from the entire surface. The diffuser plate 2 can be formed in any size, but considering the efficiency of the number of plates to be installed in the equipment, it is preferable that the area of the diffuser plate 2 is ¹⁰⁰ cm2 or more. As an example, the size of the disk-shaped diffuser plate 2 is a diameter of 165 mm and a thickness of 15 mm.

The case 3 is attached to the air diffuser plate 2 so that it seals the side and back sides of the air diffuser plate 2 and exposes the front side. The case 3 includes a main body 3a that supplies air toward the back side of the air diffuser plate 2, and a connecting member 3b to which a hose that supplies air to the main body 3a is connected. The main body 3a is a concave member formed in a shape that corresponds to the air diffuser plate 2 and has an opening for attaching the air diffuser plate 2.

As shown in FIG. 2, the main body 3a receives air supplied from the connecting member 3b in the space 3c and supplies it toward the air diffuser plate 2 installed above the space 3c. The main body 3a has a ring-shaped step 3d for installing the air diffuser plate 2 above the space 3c. The air diffuser plate 2 is sealed to the case 3 so that air does not leak from the gap between the case 3. More specifically, the air diffuser plate 2 is adhered to the step 3d using an adhesive, and the gap between the air diffuser plate 2 and the case 3 is sealed using a sealant.

The diffuser plate 2 is a sintered body (ceramics) obtained by sintering a mixture containing combustion ash. Specifically, the diffuser plate 2 is obtained by mixing combustion ash with a binder, adding water to the mixture, molding it into a desired shape, and then sintering the resulting molded body. As a result of extensive research by the inventors, it was discovered that by optimizing the composition and blending ratio of the raw materials, the components of the combustion ash, and the firing conditions, it is possible to manufacture a diffuser plate 2 that can uniformly spray air bubbles from the entire surface using a simple manufacturing process, even when the raw materials contain combustion ash.

The raw materials for the diffuser plate 2 include combustion ash and a binder. Other additives may be added to the raw materials for the diffuser plate 2. Combustion ash is the main component of the raw materials for the diffuser plate 2, and is, for example, coal ash and biomass combustion ash. Coal ash is ash obtained by burning coal, and is preferably fly ash. Fly ash is coal ash generated when pulverized coal is burned and collected in a dust collector. Biomass combustion ash is ash obtained by burning biological resources derived from animals and plants, such as wood, livestock manure, sewage sludge, and agricultural residues. Combustion ash is continuously discharged from thermal power plants, so it can be obtained stably and cheaply. It is preferable that the raw materials for the diffuser plate 2, excluding moisture, contain at least 50 wt% combustion ash.

It is preferable to select combustion ash with as low a calcium and iron content as possible. This is because calcium and iron are factors that cause shrinkage and cracking of the fired body. It is preferable that the calcium and iron content in the combustion ash is lower than that of the clay to be mixed with it. Specifically, for example, it is preferable that the calcium and iron content in the combustion ash is 5 wt% or less.

The binder, also called a binding material, binds the particles of the combustion ash together. The binder is, for example, clay or a cellulose-based water-soluble polymer. Of these, clay is particularly suitable as a binder because it has excellent toughness. The cellulose-based water-soluble polymer is, for example, carboxymethyl cellulose (CMC). A plurality of types of binders may be mixed with the combustion ash. The weight ratio of the binder contained in the raw material of the air diffuser plate 2 excluding moisture is 50 wt% or less, but in order to prevent cracking and deformation during drying and firing, it is preferable that it is 30 wt% or more and 50 wt% or less.
The above is the configuration of the air diffusion device 1 and the air diffusion plate 2.

(Production method)
Next, a method for manufacturing the air diffuser plate 2 according to the embodiment will be described with reference to Fig. 3. Either a casting method or a press molding method may be used as the method for manufacturing the air diffuser plate 2. In both the casting method and the press molding method, the air diffuser plate 2 can be manufactured into any shape by changing the mold. Hereinafter, an example will be described in which coal ash and clay are used as the raw materials for the air diffuser plate 2.

First, water is added to the raw materials and mixed to create a mixture (step S11). In the casting method, coal ash and clay are mixed, water is added, and the mixture is stirred to create a slurry. On the other hand, in the press molding method, coal ash and clay are mixed, water is added, and the mixture is kneaded to create a clay-like mixture.

Next, the mixture prepared in step S11 is molded (step S12). In the casting molding method, the slurry is poured into a mold and the surface shape of the slurry is adjusted using a scraper. The mold used in the casting molding method does not need to be strong and is made of plastic, for example. On the other hand, in the press molding method, the clay-like mixture is forced into the mold and the mixture inside the mold is pressurized with a press. The mold used in the press molding method needs to be strong, so it is preferably a metal mold. In the press molding method, the mold can be removed from the molded body after pressurization with the press.

Next, the molded body produced in step S12 is dried (step S13). The molded body may be dried naturally, or may be dried by heating or blowing air using a dryer. In the case of heating and drying, the air in the dryer may be heated to a temperature in the range of 50°C to 150°C, preferably 100°C to 110°C. In the case of the casting molding method, the molded body is dried with the mold attached, and when it is dry, it is removed from the mold. The dried molded body is easily removed because it has slightly shrunk against the inner surface of the mold.

Next, the molded body dried in step S13 is fired (step S14). Specifically, the dried molded body is set in a heating furnace, and the temperature in the heating furnace is maintained at a constant temperature (firing temperature) for a certain time (firing time), thereby changing the molded body into a fired body. The firing temperature is, for example, in the range of 1000°C to 1200°C, preferably in the range of 1050°C to 1150°C, and is, for example, 1100°C. The firing time may be set according to the size of the molded body, and is, for example, in the range of 1 hour to 3 hours, and is, for example, 2 hours.
The manufacturing method of the air diffuser plate 2 has been described above.

The air diffuser plate 2 manufactured under the above conditions has an average bubble diameter of 1 mm or less when gas is sprayed into water, has a pressure resistance of 0.2 MPa or more, and can spray fine air bubbles into water at a flow rate of 200 L/min or more per ^m2 of unit area. In addition, the shrinkage rate during firing is suppressed to 5% or less based on the molded body before drying, so cracks and deformations in the air diffuser plate 2 can be prevented.

Whether to use the casting molding method or the press molding method as the manufacturing method for the air diffuser plate 2 can be determined comprehensively, taking into consideration the skill of the worker, the required quality, and the need for mass production. With the casting molding method, an air diffuser plate 2 that uniformly releases fine bubbles can be obtained, but compared to the press molding method, it is more time-consuming to manufacture and is not suitable for mass production. On the other hand, with the press molding method, it is more difficult to obtain an air diffuser plate 2 that uniformly releases fine bubbles than with the casting molding method, and the molding die is expensive, but the kneaded body is easier to handle than a slurry, and it is rather suitable for mass production.

(Assembly method)
Hereinafter, a method of assembling the air diffusion device 1 according to the embodiment will be described with reference to Fig. 4. First, the air diffusion plate 2 is attached to the case 3 using an adhesive (step S21). Specifically, the adhesive is applied to the step 3d of the case 3, and the bottom surface of the air diffusion plate 2 is pressed against the step 3d. It is preferable to use an adhesive with high viscosity, for example, an epoxy adhesive, as the adhesive.

Next, the gap between the air diffusion plate 2 and the case 3 is sealed with a sealant (step S22). Specifically, the sealant is poured into the gap between the air diffusion plate 2 and the case 3 using a syringe so as to fill the gap. As the sealant, it is preferable to use a hardener that has a lower viscosity and a higher fluidity than an adhesive, and for example, an epoxy resin is used.
The above is the method for assembling the air diffuser 1.

As described above, the air diffuser plate 2 according to the embodiment is made of a porous body containing combustion ash and a binder, has a pair of opposing surfaces, and receives air on one surface in liquid and releases fine bubbles from the other surface. Therefore, it can be manufactured in a simple process using combustion ash, an inexpensive raw material. As a result, the air diffuser plate 2 can be manufactured at low cost, and the combustion ash discharged in large quantities from facilities equipped with combustion equipment such as thermal power plants and steelworks can be effectively utilized, reducing the cost of disposing of the combustion ash and the burden on the environment.

The present invention is not limited to the above embodiment, and the following modifications are also possible.

(Modification)
In the above embodiment, the air diffuser plate 2 is formed in a disk shape, but the present invention is not limited to this. The air diffuser plate 2 can be formed in any shape, and may be formed as a rectangular plate, for example. The air diffuser plate 2 is merely one example of an air diffuser that has a pair of surfaces at different positions and receives air at one surface in liquid and releases fine bubbles from the other surface, and the air diffuser may be formed as, for example, a cylindrical air diffuser that receives air at its inner surface and releases fine bubbles from its outer surface.

In the above embodiment, in order to prevent cracking during firing, the ratio of binder contained in the raw materials excluding moisture is set to 50 wt% or less, and the component ratios of calcium and iron contained in the combustion ash are each set to 5 wt% or less, but the present invention is not limited to this. Factors that cause shrinkage during firing include the composition and blending ratio of the raw materials and the components of the combustion ash, as well as other factors such as the particle size of the raw materials, so a condition can be set to use raw materials with a shrinkage rate of 5% or less during firing.

In the above embodiment, the raw materials including combustion ash and clay are mixed, water is added to the mixture, the mixture is molded using a frame, and the molded body is dried and fired to manufacture the air diffuser plate 2, but the present invention is not limited to this. For example, a slice molding method may be used in which molding and firing are performed in the same manner as for making bricks, and the obtained block-shaped fired body is sliced.

To explain the procedure of the slice molding method in detail, the raw materials are mixed, extruded, and cut in sequence to produce a block-shaped molded body, which is then dried and fired to produce a block-shaped fired body having a shape similar to that of a brick. The extruded mixture can be cut into individual blocks with, for example, a piano wire to produce a block-shaped molded body. The resulting block-shaped fired body is then sliced to the desired thickness using a cutting means such as a diamond cutter. Although it is difficult to produce the air diffuser plate 2 in any shape with the slice molding method, it is suitable for mass production and quality control is also easy.

The above embodiments are examples, and the present invention is not limited to these, and various embodiments are possible without departing from the spirit of the invention described in the claims. The components described in the embodiments and variations can be freely combined. Furthermore, inventions equivalent to the inventions described in the claims are also included in the present invention.

The present invention will be specifically explained below with reference to examples. However, the present invention is not limited to these examples.

Example 1
In Example 1, various test specimens were prepared by using coal ash and clay as raw materials and varying the type of coal (coal grade) from which the coal ash was made, the mixing ratio of the raw materials, and the firing conditions. The test specimens were prepared using a press molding method. After that, air bubbles were generated while the test specimens were set in a case in water to verify whether the test specimens functioned as air diffusers.

The coal ash is fly ash (FA) separated from the exhaust of a coal-fired power plant. The FA used as the raw material was three types: 100% coal ash A, 70% coal ash B, 30% coal ash C, 80% coal ash D, and 20% coal ash E. The coal ashes A to E are coal types with different component ratios. For example, 70% coal ash B and 30% coal ash C mean that 70% coal ash B and 30% coal ash C are mixed by weight. The raw material mixing ratios were three patterns: FA:clay = 80%:20%, FA:clay = 70%:30%, and FA:clay = 50%:50% by weight. The size of the test specimens created was 100 mm square and 10 mm thick. The firing temperatures were 1000°C, 1100°C, and 1200°C, and the firing time was 2 hours in each case.

As a result, as shown in Figures 5 to 7, when the molded bodies were fired at firing temperatures of 1000°C, 1100°C, and 1200°C, fired bodies were obtained and it was confirmed that they functioned as air diffusers in water. Specifically, when the firing temperature was 1100°C, good test bodies were obtained in terms of strength, shape, and function. However, when the firing temperature was 1200°C, the test bodies were easily distorted, and some of the coal types melted and peeled off. Furthermore, when the firing temperature was less than 1000°C, the strength of the test bodies was insufficient, and they could not withstand the gas pressure when bubbles were generated, resulting in cracks and peeling. From the above, it can be understood that the firing temperature during firing is preferably 1100°C. It can also be understood that the coal type and the blending ratio of the raw materials have almost no effect on the strength and performance of the air diffuser.

Example 2
In Example 2, the relationship between the composition and blending ratio of the raw materials and cracking of the fired body was examined. First, the raw materials were mixed under the conditions shown in Samples 1 to 4 in FIG. 8, molded using a press molding method, dried, and fired to create eight test specimens for each condition. The combustion ash A in FIG. 8 is fly ash. The weight of the raw materials excluding water is 500 g for all test specimens. The diameter of the test specimen before firing is 165 mm, and the thickness is about 15 mm. The pressing pressure applied to the test specimen before firing is 5 tons. The drying conditions are natural drying or heat drying at a temperature of 105°C. Based on the results of Example 1, the firing temperature was set to 1100°C and the firing time was set to 2 hours.

As a result, as shown in Figure 9, fired bodies were obtained for all samples 1 to 4. Sample 1 was made by simply mixing clay with water, which caused a large amount of shrinkage and many small cracks. Seven out of eight samples each for samples 2 and 3 had no cracks, and the remaining sample only had a small crack at the edge. Sample 4 did not contain clay and had low toughness, which is likely why large cracks occurred during firing. From the above, it can be seen that if there is a large amount of shrinkage during firing, the fired body is prone to cracks and deformation, and that the combination of coal ash and clay is an ideal raw material for air diffuser plates.

Example 3
In Example 3, the relationship between the component ratio of coal ash and the shrinkage rate during firing was examined. Specifically, 1% CMC was added to each of combustion ash A and B having the component ratios shown in Figure 10, and then water was added and kneaded, and test specimens were prepared by press molding, and the shrinkage rate during firing was measured. Combustion ash A and B in Figure 10 are fly ashes derived from different coal types. The other conditions are the same as in Example 2. For comparison, a similar experiment was also conducted on clay having the component ratios shown in Figure 10. Only water was added to the clay and kneaded, and test specimens were prepared by press molding.

As a result, the shrinkage rate of the test specimen using combustion ash A was 1.8%, while the shrinkage rates of the test specimens using clay and combustion ash B were 6.1% and 7.3%, respectively. The test specimen using combustion ash A showed almost no deformation, whereas the test specimens using clay and combustion ash B showed cracks and warping as shown in Figure 11 due to their large shrinkage rates. From the above, it can be understood that it is preferable to use combustion ash with a small calcium and iron content ratio as the raw material for the air diffuser plate.

Example 4
In Example 4, it was verified whether the casting method can be used as a manufacturing method for the air diffuser plate. Specifically, first, combustion ash and clay were mixed, and water was added to create a slurry. The combustion ash was fly ash. The raw material blend ratio was 80% combustion ash and 20% clay, taking into account the results of Example 2, and the total weight was 1000 g. The amount of water added was 40% by weight. Next, as shown in FIG. 12, the slurry was poured into a mold, the surface shape was adjusted, and then the mixture was heated and dried at 105°C for 24 hours using a dryer. The shape of the mold was 165 mm in diameter and about 15 mm to 34 mm in thickness. Next, after drying, the mold was removed, and firing was performed at a firing temperature of 1100°C and for 2 hours in the same manner as in Example 2. As a result, it was confirmed that a fired body of combustion ash and clay could be obtained using the casting method, as shown in FIG. 12.

Example 5
In Example 5, it was verified whether the slicing method can be used as a manufacturing method for the diffuser plate. Specifically, combustion ash and clay were mixed, water was added to create a kneaded product, and the mixture was kneaded and fired in the same manner as in the case of bricks using a production line in a brick factory. The combustion ash was fly ash. The raw material ratio was 50% combustion ash and 50% clay. As a result, a fired block could be obtained as shown in FIG. 13. The cross section of this block was rectangular, with dimensions of 100 mm x 100 mm. Using a diamond cutter, it was possible to slice it to a thickness of 15 mm, which is suitable as the thickness of the diffuser plate. It was also confirmed that the sliced diffuser plate could release fine bubbles in water.

Example 6
In Example 6, the average bubble diameter of bubbles generated by the air diffuser plate was measured. Specifically, air was sent to the air diffuser plate to which the case was attached to generate bubbles, and the bubbles in the water were visualized by the backlight method, photographed by a high-speed camera, and the photographed image was subjected to image analysis to calculate the bubble diameter. The Sauter average value was calculated from the calculated bubble diameter to obtain the average bubble diameter. The test specimens were three patterns: an air diffuser plate with a thickness of 15 mm created by the press molding method, and air diffusers with thicknesses of 27 mm and 34 mm created by the casting molding method. All of the air diffusers were disk-shaped.

As a result, as shown in Figure 14, fine bubbles with an average bubble diameter of 1 mm or less were generated in all test specimens. The air diffuser plate made by the casting method had a smaller average bubble diameter than the air diffuser plate made by the press molding method. In addition, the air diffuser plate made by the casting method had fine bubbles generated uniformly, whereas the air diffuser plate made by the press molding method had some surfaces with fewer bubbles from the center, and there was variation in the generation of bubbles. This is thought to be because the press molding method is prone to unevenness when filling the mold with raw materials and applying press pressure.

(Example 7)
In Example 7, it was verified whether or not neutralization treatment can be performed on concrete factory wastewater using an aeration plate. In the experimental device, 20 L of concrete factory wastewater with a pH of 12.42 was stored in a water tank as shown in FIG. 15, carbon dioxide gas was supplied to the concrete factory wastewater, and the change in pH value over time was measured. Carbon dioxide gas was supplied from a liquefied gas cylinder (CO ₂ 99.5%), and the gas flow rate was 1.0 L/min. The test specimens were a 34 mm thick aeration plate made by a casting molding method, and commercially available aeration plates A and B. All of the test specimens were standardized to an area of 60 cm ^2. The commercially available aeration plate A is an aeration plate actually used in a neutralization treatment device, and the commercially available aeration plate B is an aeration plate commercially available as an air stone for raising fish.

As a result, as shown in Figure 16, the air diffuser plate made by the casting method had the same neutralization efficiency as the commercially available air diffuser plate A, and was more efficient than the commercially available air diffuser plate B. In addition, when it was verified whether neutralization treatment could be performed by replacing carbon dioxide gas containing 99.5% _CO2 with exhaust gas (component ratio: _CO2 10%, _O2 10%, _N2 80%) collected from a thermal power plant, the pH of concrete waste liquid was similarly successfully lowered to 7.

1 Air diffuser 2 Air diffuser plate 3 Case

In order to achieve the above object, the air diffuser according to the present invention comprises:
A diffuser that is composed of a porous body containing combustion ash and a binder, changes the received gas into fine bubbles by passing the gas through the diffuser, and releases the bubbles into the liquid .
It has a pressure resistance strength of 0.2 MPa or more, and is configured so that when it receives pressurized gas from the outside, it can emit fine bubbles into liquid at a flow rate of 200 L/min or more per ^m2 unit area from the surface of the diffuser.

Claims (8)

An aeration body made of a porous material containing combustion ash and a binder, with a pair of surfaces located at different positions, which receives gas in liquid on one surface and releases fine bubbles from the other surface. The binder is clay.
The air diffuser according to claim 1. The ratio of the combustion ash in the raw material of the diffuser is 50 wt % or more, and the ratio of the binder is 50 wt % or less.
The air diffuser according to claim 1 or 2. The calcium and iron contained in the combustion ash are each 5% by weight or less;
The air diffuser according to claim 1 or 2. A mixing step of mixing combustion ash, a binder, and water;
a molding step of molding the mixture mixed in the mixing step;
a drying step of drying the molded body obtained by the molding step;
A firing step of firing the dried molded body;
A method for manufacturing an aeration body comprising the steps of: In the firing step, the dried molded body is fired at a constant temperature set within a range of 1000°C to 1200°C.
A method for manufacturing the air diffuser according to claim 5. In the mixing step, a slurry containing the combustion ash, the binder, and the water is generated,
In the molding step, the generated slurry is poured into a mold.
A method for producing the air diffuser according to claim 5 or 6. In the mixing step, a kneaded material containing the combustion ash, the binder, and the water is generated,
In the molding step, the produced kneaded material is pressed into a mold and pressurized.
A method for producing the air diffuser according to claim 5 or 6.

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