KR102588107B1 - Ocher board for radon radiation reduction and method of the same - Google Patents

Abstract

The red clay board for reducing radon emission according to the present invention and its manufacturing method include adding a polyvinyl alcohol adhesive to the red clay mixed powder mixed with 0.1 to 1 part by weight of charcoal powder and 0.1 to 1 part by weight of activated carbon powder based on 100 parts by weight of red clay powder. and mixing step (S100); Characterized by including a step (S200) of injecting and molding the mixed liquid into a wood mold.

Description

Red clay board for reducing radon emissions and its manufacturing method {OCHER BOARD FOR RADON RADIATION REDUCTION AND METHOD OF THE SAME}

The present invention relates to a red clay board for reducing radon emission, which is used in building materials and has excellent radon emission reduction characteristics, and a method of manufacturing the same.

The World Health Organization (WHO) reported in 2002 that 2.4 million people die every year from air pollution, of which 1.5 million die from indoor air pollution. These statistics mean that while the quality of air outside a building is important to modern people who live indoors for more than 80% of 24 hours a day, the quality of indoor air is even more important. Therefore, securing comfortable and healthy indoor air quality is of utmost importance in improving the quality of life.

In the building sector, indoor air management conditions are becoming increasingly worse due to lack of ventilation due to airtightness of buildings and reinforcement of insulation due to energy-saving design and construction. Moreover, gases and hazardous substances emitted from various building materials have recently been known to be very harmful to the human body, but most are not aware of the serious impact they have on the comfort and health of residents.

In particular, building syndrome, the cause of which is unknown, often occurs in new buildings. This is a phenomenon that occurs when the concentration of pollutants generated from various building materials continues to circulate and increases in a limited indoor space with relatively insufficient ventilation. The phenomenon of building syndrome, in which many people complain of headaches, dizziness, nausea, drowsiness, eye irritation, and decreased concentration in closed buildings, is a serious threat to the health of occupants and is causing a decline in productivity and efficiency.

Therefore, it is urgently necessary to investigate and analyze the characteristics of pollutants emitted from building materials and their impact on indoor space, and to prepare reasonable countermeasures. In particular, modern people spend most of their daily lives indoors and are gradually airtightening their indoor living spaces to save energy. As a result, pollutants that deteriorate indoor air quality, such as fine dust, asbestos, formaldehyde, toluene, xylene, and radon, accumulate indoors and further have a harmful effect on the human body (see Table 1).

division item standard Go ^* me ^** Da ^*** la ^**** Maintenance standards
5 items PM 10(㎍/m ³ ) 150 100 200 200 Carbon dioxide (ppm) 1000 - Formaldehyde (㎍/m ³ ) 100 - Total floating bacteria (CFU/m ³ ) - 800 - - Carbon monoxide (ppm) 10 25 - Recommended standards
5 items Nitrogen dioxide (ppm) 0.05 0.3 - Radon (Bq/m ³ ) 148 - Total volatile organic compounds (㎍/m ³ ) 500 400 1000 - PM 2.5 (㎍/m ³ ) - 70 - - Mold (CFU/m ³ ) - 500 - -

※ In Table 1 above, “a” refers to subway stations, underpass shopping malls, railroad stations, passenger car terminals, port facilities, waiting rooms, airport facilities, passenger terminals, libraries, museums, art galleries, large-scale stores, funeral markets, movie theaters, academies, and exhibitions. Facility, Internet computer game facility, "I" is a daycare center, elderly care facility, postpartum care center, medical institution, "C" is an indoor parking lot, and "D" is an indoor sports facility, indoor performance hall, office facility, two or more uses. This is a building used for.

Patent Document 0001 describes (1) mixing 75 to 80 parts by weight of red clay with a moisture content of 7 to 15%, 20 to 25 parts by weight of a solidifying agent containing pozzolan mineral material, and 1 to 3 parts by weight of an inorganic coagulant, and 7 to 15 parts by weight of water. further mixing to prepare a raw material composition; (2) installing Korean paper on the top, bottom, and sides of the raw material composition and pressing it with a press to remove moisture and air bubbles in the raw material composition and press the surface flatly to produce a pressed molded product through a pressing and molding process; And (3) drying the pressed molded product to produce a red clay board; wherein the inorganic coagulant is NaCl, CaCl2, KCl, MgCl2, Na2SO4, FeCl2 at 25~35:15~30:12~28:5. It is comprised in a weight ratio of ~10:1~7:1~3, and the solidifying agent is blast furnace slag powder containing pozzolan mineral material, lime, anhydrous gypsum, silica fume, metakaolin, and calcium sulfoaluminate. There is a description of a method of manufacturing a red clay board, characterized in that it contains (Calcium sulphoaluminate cements: CSA) in a weight ratio of 50-60: 1-20: 20-30: 1-2: 1-5: 1-5. .

Patent document 0002 includes a main body in which a hollow part is formed inside to surround an object emitting radioactive material, and an opening is formed in communication with the hollow part so that the object can enter the inside of the hollow part; an adsorption filter installed on the inner wall of the main body and adsorbing radioactive substances generated from the object; An air circulation device that forcibly circulates air inside or outside the main body; wherein the adsorption filter adsorbs radioactive substances having an adsorption performance for either iodine generated from medical devices or radon generated from soil. There is a description of the filtering device.

In this way, research is being actively conducted on the development of liquid paint using eco-friendly charcoal and filters for radon removal using granular activated carbon. However, in the case of powdered activated carbon and granular activated carbon used in existing filter technologies, limitations such as scattering due to dust and lack of radon adsorption capacity still exist.

Korean Patent No. 10-1747877 (Title of invention: Manufacturing method of red clay board and red clay board manufactured thereby, Registration date: 2017.06.09.) Korean Patent No. 10-2034666 (Title of invention: Radioactive material adsorption filtering device, Registration date: 2019.10.22.)

The purpose of the present invention is to provide a red clay board for reducing radon emission and a manufacturing method for absorbing radon radiation with high efficiency, which can improve the reduction rate of radon concentration contained in building materials.

In order to achieve the above object, one aspect of the present invention is to add and mix a polyvinyl alcohol adhesive solution to the red clay mixed powder mixed with 0.1 to 1 part by weight of charcoal powder and 0.1 to 1 part by weight of activated carbon powder with respect to 100 parts by weight of red clay powder. Step (S100); It includes a method of manufacturing a red clay board for reducing radon emissions, including the step of injecting and molding the mixed solution into a wood mold (S200).

The polyvinyl alcohol adhesive solution may have a solid content of 5 to 10% by weight.

The red clay board for reducing radon emission may include 150 to 200 parts by weight of the polyvinyl alcohol adhesive solution based on 100 parts by weight of the red clay mixture powder.

The red clay mixed powder is made by adding the red clay powder, charcoal powder, and activated carbon powder to an aqueous solution containing polysaccharides, irradiating the added aqueous solution with ultrasonic waves with an ultrasonic horn, and drying it, using the particles of the red clay powder as central particles. It may be a composite powder in which particles of the charcoal powder and particles of the activated carbon powder are alternately arranged on the surface of the particle.

The method of manufacturing a red clay board for reducing radon emission may include a step (S150) of adding and mixing a molding additive to the mixed solution between the mixing step (S100) and the molding step (S200).

The molding additive may include 160 to 1,600 parts by weight of colloidal silica, 20 to 50 parts by weight of silane, 2 to 10 parts by weight of organic acid, and 2 to 10 parts by weight of an anti-adhesion agent, based on 100 parts by weight of the red clay powder.

Another aspect of the present invention includes a red clay board for reducing radon emissions manufactured by the method for manufacturing a red clay board for reducing radon emissions described above.

The present invention has the advantage of increasing the absorption rate of radon radiation and preventing agglomeration between particles while maintaining high packing density by including red clay mixed powder and polyvinyl alcohol adhesive.

In addition, the present invention can further increase the absorption rate of radon radiation by including red clay mixed powder obtained by ultrasonic irradiation with an ultrasonic horn.

In addition, the present invention further includes a mixing step of adding a molding additive, thereby improving the compressive strength of the red clay board and further increasing the absorption rate of radon radiation.

Even if the effect is not explicitly mentioned in the present invention, the effect described in the specification expected by the technical features of the present invention and the inherent effect thereof are treated as if described in the specification of the present invention.

Figure 1 is a process flow chart showing the process sequence of a method for manufacturing a red clay board for reducing radon emissions according to an aspect of the present invention.
In detail, Figure 2 is a schematic diagram conceptually showing the manufacturing process of the red clay mixed powder of the red clay board manufacturing method for reducing radon emissions according to one aspect of the present invention.
Figure 3 is a process flow chart showing another process sequence of the method for manufacturing a red clay board for reducing radon emissions according to an aspect of the present invention.
Figure 4 is an actual photograph showing a red clay board for reducing radon emissions according to another aspect of the present invention.
Figure 5 is an actual photograph showing a chamber for measuring radon radiation used in an experimental example of the present invention.

Unless otherwise defined, the technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art to which this invention pertains, and the gist of the present invention is summarized in the following description and accompanying drawings. Descriptions of known functions and configurations that may unnecessarily obscure are omitted. In this specification and the appended claims, units used without special mention are based on weight, and for example, units of % or ratio mean weight % or weight ratio.

Figure 1 is a process flow chart showing the process sequence of a method for manufacturing a red clay board for reducing radon emissions according to an aspect of the present invention.

As shown in Figure 1, the method of manufacturing a red clay board for reducing radon emission according to an aspect of the present invention includes a mixing step (S100) of mixing a red clay mixture powder mixed with red clay powder, charcoal powder, and activated carbon powder and a polyvinyl alcohol adhesive solution. ) and a molding step (S200) of injecting and molding the mixed solution obtained in the mixing step (S100) into a molten mold.

The red clay powder has a pH of 8.5 to 9.5 and is a powder made of porous particles. Its surface has a honeycomb structure and numerous spaces form a multi-layer structure. Inside these sponge-like pores, a large amount of far-infrared rays are absorbed and stored, and are emitted when heated. It plays a role in stimulating the molecular activity of other objects.

The charcoal powder is a powder having a particle size distribution of 80 to 85% particles with a mesh size of 6 to 40, and has a plate-shaped porous powder form. Accordingly, the red clay board for reducing radon emission can have a high absorption rate of radon radiation.

Specifically, the mesh size of the charcoal powder may satisfy the following relations 1 to 5.

[Relationship 1]

7 ≤ D1 ≤ 10

[Relational Expression 2]

20 ≤ D2 ≤ 25

[Relational Expression 3]

30 ≤ D3 ≤ 35

[Relational Expression 4]

0.3 ≤ h1/h2 ≤ 0.4

[Relational Expression 5]

0.6 ≤ h2/h3 ≤ 0.7

(In the above equations 1 to 5, D1 is the center size of the first peak with the largest center size, based on the center size of the peak in the size distribution of the charcoal powder, and D2 is the size distribution of the charcoal powder, Based on the center size of the peak, D3 is the center size of the second peak with the second largest center size, and D3 is the third peak with the smallest center size in the size distribution of the charcoal powder, based on the center size of the peak. is the center size of, h1 is the center height of the first peak, h2 is the center height of the second peak, and h3 is the center height of the third peak.)

The mesh size distribution of the charcoal powder may be measured using Dynamic Light Scattering (DLS). In detail, the size distribution of the charcoal powder may be measured under the conditions of a temperature of 25 ° C. and a sample concentration of 0.01 to 0.1% by weight. Additionally, the size distribution of the charcoal powder may be a size distribution represented by the diameter of the particle and the number of particles having the corresponding diameter. Meanwhile, a size distribution of at least three modal or more may mean that at least three or more peaks exist in the size distribution of the charcoal powder. At this time, the size (particle diameter) corresponding to the center of the peak is the center size, the particles belonging to the first peak with the smallest center size are the first particles, and the particles belonging to the second peak with the second largest center size are the first particles. As second particles, particles belonging to the third peak with the largest central size are collectively referred to as third particles.

As such, in the method of manufacturing a red clay board for reducing radon emission according to an aspect of the present invention, the charcoal powder has a three-modal distribution and satisfies the above relations 1 to 5, thereby reducing the radon content of the final manufactured red clay board for reducing radon emission. The radiation absorption rate can be increased and the occurrence of defects such as cracks or voids on the inside or surface of the red clay board can be prevented.

Meanwhile, the activated carbon powder is a powder with a mesh size of 8 to 30 and an iodine adsorption amount of 1000 to 1100 mg/g, and has a plate-shaped porous powder form. Accordingly, the red clay board for reducing radon emission can have a high absorption rate of radon radiation.

Specifically, if the iodine adsorption amount of the activated carbon powder is less than 1000 mg/g, the contact area with the polyvinyl alcohol resin decreases, lowering the viscosity of the mixed solution, and dispersibility is not improved, and if the iodine adsorption amount is more than 1100 mg/g, the mixed solution If the viscosity is excessive, the final board may deteriorate or lose strength.

More specifically, the mesh size of the activated carbon powder may satisfy the following relations 6 to 10.

[Relational Expression 6]

8 ≤ D1 ≤ 12

[Relational Equation 7]

15 ≤ D2 ≤ 20

[Relational Expression 8]

25 ≤ D3 ≤ 30

[Relationship 9]

0.3 ≤ h1/h2 ≤ 0.4

[Relation 10]

0.6 ≤ h2/h3 ≤ 0.7

(In the above equations 6 to 10, D1 is the center size of the first peak with the largest center size, based on the center size of the peak in the size distribution of the activated carbon powder, and D2 is the size distribution of the activated carbon powder, Based on the center size of the peak, D3 is the center size of the second peak with the second largest center size, and D3 is the third peak with the smallest center size based on the center size of the peak in the size distribution of the activated carbon powder. is the center size of, h1 is the center height of the first peak, h2 is the center height of the second peak, and h3 is the center height of the third peak.)

The mesh size distribution of the activated carbon powder may be measured using Dynamic Light Scattering (DLS). In detail, the size distribution of the activated carbon powder may be measured under the conditions of a temperature of 25 ° C. and a sample concentration of 0.01 to 0.1% by weight. Additionally, the size distribution of the activated carbon powder may be a size distribution expressed by the diameter of the particles and the number of particles having the corresponding diameter. Meanwhile, a size distribution of at least three modal or more may mean that at least three or more peaks exist in the size distribution of activated carbon powder. At this time, the size (particle diameter) corresponding to the center of the peak is the center size, and the particles belonging to the first peak with the smallest center size are the first particles, and the particles belonging to the second peak with the second largest center size are the first particles. As second particles, particles belonging to the third peak with the largest central size are collectively referred to as third particles.

As such, in the method of manufacturing a red clay board for reducing radon emission according to an aspect of the present invention, the activated carbon powder has a three-modal distribution and satisfies the above relations 6 to 10, thereby reducing the radon of the final manufactured red clay board for reducing radon emission. The radiation absorption rate can be increased and the occurrence of defects such as cracks or voids on the inside or surface of the red clay board can be prevented.

In addition, during the mixing step (S100), the red clay mixed powder may be included by mixing 0.1 to 1 part by weight of the charcoal powder and 0.1 to 1 part by weight of the activated carbon powder with respect to 100 parts by weight of the red clay powder. If the amount of the charcoal powder is less than 0.1 parts by weight based on 100 parts by weight of the red clay powder, it is undesirable because the effect of the charcoal powder described above is extremely minimal, and if the amount of the charcoal powder is more than 1 part by weight, miscibility during the mixing step (S100) It is undesirable because it inhibits and darkens the color of the red clay board, which is undesirable because there is a risk of lowering its value as a building interior material. In addition, if the activated carbon powder is less than 0.1 part by weight relative to 100 parts by weight of the red clay powder, it is undesirable because the effect of the activated carbon powder described above is extremely minimal, and if the activated carbon powder is more than 1 part by weight, the mixing ability during the mixing step (S100) It is undesirable because it inhibits the color of the red clay board, and because it darkens the color of the red clay board, it is undesirable because there is a risk of lowering its value as a building interior material.

The polyvinyl alcohol adhesive solution has a solid content of 5 to 10% by weight, and the red clay board for reducing radon emissions may include 150 to 200 parts by weight of the polyvinyl alcohol adhesive solution based on 100 parts by weight of the red clay mixture powder. . In the above range, while maintaining the high packing density of the red clay mixed powder in the red clay board for reducing radon emission, each red clay powder, charcoal powder, and activated carbon powder can simultaneously adsorb radon radiation with high efficiency through several paths, and coagulate between particles. can be prevented.

Meanwhile, the red clay mixed powder may be a combination of red clay powder, charcoal powder, and activated carbon powder. In the present invention, the charcoal powder and activated carbon powder are effective in that they significantly improve the radon emission reduction characteristics, but are easily agglomerated. There is a problem in that uniform dispersion within the solution is difficult. However, in the present invention, uniform dispersion is made possible through ultrasonic treatment, which will be described later, thereby giving the composition of the present invention excellent radon emission reduction properties.

The red clay mixed powder may be a composite powder in which particles of the charcoal powder and particles of the activated carbon powder are alternately arranged on the surface of the red clay powder particles.

In detail, Figure 2 is a schematic diagram conceptually showing the manufacturing process of the red clay mixed powder of the red clay board manufacturing method for reducing radon emissions according to one aspect of the present invention.

As shown in Figure 2, the red clay mixed powder is prepared by adding the red clay powder, charcoal powder, and activated carbon powder to a polysaccharide-containing aqueous solution, irradiating the added polysaccharide-containing aqueous solution with ultrasonic waves with an ultrasonic horn, and drying the particles of the red clay powder. It may include composite particles 100 in which the particles 120 of the charcoal powder and the particles 130 of the activated carbon powder are alternately arranged on the surface of the red clay powder particles 110 with (110) as the central particle. You can.

The polysaccharide is preferably sucrose.

The polysaccharide-containing aqueous solution may contain 1 to 10% by weight of the sucrose.

Specifically, 1 to 5 parts by weight of the red clay mixed powder may be added to 100 parts by weight of the polysaccharide-containing aqueous solution. In this weight range of the red clay mixed powder, the charcoal powder particles 120 and the activated carbon powder particles 130 are adsorbed on the surface of the red clay powder particles 110.

In addition, the ultrasonic horn is provided in a horn-type ultrasonic irradiator. The horn-type ultrasonic irradiator generates ultrasonic waves using piezoelectric ceramics and an ultrasonic oscillator that converts electrical energy into mechanical vibration energy using the reverse piezoelectric effect. In order to expand the amplitude of the ultrasonic waves, the vibrator can be equipped with a booster and a horn. This horn-type ultrasonic irradiator acts as a very high energy source because the internal temperature and pressure of the cavitation bubbles generated when ultrasonic waves are irradiated into an aqueous solution are very high, and when the bubbles grow and rupture, high-temperature and high-pressure shock waves are generated. It is used to mix or disperse heterogeneous liquids that are difficult to mix.

For example, the ultrasonic irradiation may be performed at a frequency of 40 to 60 kHz. Within the above frequency range, more effective dispersion of the red clay powder particles 110, charcoal powder particles 120, and activated carbon particles 130 is possible, and thus the red clay powders of the three types of core-shell structures in the polysaccharide-containing aqueous solution Particles, charcoal powder particles, and activated carbon particles are uniformly dispersed, injected into a wood mold, and then packed densely and uniformly, so that when the red clay board for radon emission reduction is manufactured as described later, radon is reduced uniformly throughout the board. The properties are improved, which results in a uniform radon reduction effect on the board, and further, the mechanical strength of the board using red clay powder, etc. can be improved.

During the ultrasonic irradiation, if the irradiation is below the above-mentioned frequency range, it is difficult to effectively achieve uniform dispersion, and if the irradiation is above the above-mentioned frequency range, the composite particles of the core-shell structure may be damaged, resulting in uniform dispersion. This may be difficult, and there is a problem that radon reduction characteristics may be deteriorated.

Additionally, the ultrasonic irradiation time may be 1 to 3 hours, but the present invention is not limited thereto.

Figure 3 is a process flow chart showing another process sequence of the method for manufacturing a red clay board for reducing radon emissions according to an aspect of the present invention.

As shown in Figure 3, the method for manufacturing a red clay board for reducing radon emission according to an aspect of the present invention is between the mixing step (S100) and the forming step (S200) described above, to the mixed solution prepared in the mixing step (S100). It may include a mixing step (S150) of adding and mixing the molding additive.

The molding additive may include colloidal silica, silane, organic acid, and anti-adhesion agent.

In detail, the colloidal silica not only has great physical strength such that it does not dissolve or soften under acidic conditions, but is also chemically stable at high temperatures and can have a high surface area. The colloidal silica may be manufactured from sodium silicate using an ion exchange method and an acid-neutralization method, and the particles may be grown to produce particles with a uniform size distribution.

The silica content of the colloidal silica may include 20 to 50% by weight. Colloidal silica at a high concentration of 50% by weight or more tends to cause silica to gel or precipitate, so it may be difficult to prepare a dispersion in which particles are uniformly dispersed. Additionally, the colloidal silica may contain 50 to 70% by weight of polyethylene glycol. This can be stably dispersed in the mixed liquid to be stored and transported.

The amount of colloidal silica may be 160 to 1,600 parts by weight based on 100 parts by weight of the red clay powder. If the amount of colloidal silica is less than 160 parts by weight or more than 1600 parts by weight, the viscosity, gelation, and miscibility of the mixed solution may decrease, and the bending strength of the final manufactured red clay board may be reduced.

The silane is used together with the colloidal silica to improve the miscibility of the mixed solution, improve formability when manufacturing the red clay board, and improve the strength of the red clay board.

The silane may be 20 to 50 parts by weight based on 100 parts by weight of the red clay powder. If the amount of silane is less than 20 parts by weight or more than 50 parts by weight, the viscosity, gelation, and miscibility of the mixed solution may decrease, and the bending strength of the final manufactured red clay board may be reduced.

The organic acid can be very effective in dispersing various particles such as oxide particles contained in red clay. The organic acid may be one or two or more selected from the group consisting of acetic acid, lactic acid, formic acid, and combinations thereof, but the present invention is not limited thereto.

The anti-adhesion agent can prevent red clay powder, etc. from adhering to the wood mold during molding. The anti-adhesion agent may be one or two or more selected from the group consisting of glycerin, mineral oil, ferrosol, and combinations thereof, but the present invention is not limited thereto.

The present invention also provides a red clay board for reducing radon emissions.

The red clay board for reducing radon emission according to another aspect of the present invention is characterized by being manufactured by the above-described red clay board manufacturing method for reducing radon emission.

Hereinafter, the present invention will be described in detail through examples. However, these are intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to the following examples.

(Production Example 1)

Charcoal powder was prepared by pulverizing charcoal lumps with a fixed carbon content of 62% and a mineral content of 15.5%. The grinding conditions were that the charcoal lump was pulverized with a planetary mill for 1 hour, and the charcoal powder had particles with D1 having an 8 mesh size, D2 having a 22 mesh size, D3 having a 34 mesh size, h1/h2 being 0.34, and h2/h3 being 0.66. Size distribution was confirmed.

(Production Example 2)

Activated carbon powder was prepared by pulverizing granular activated carbon with a particle size of 3 to 5 mesh. The grinding conditions were that granular activated carbon was pulverized with a planetary mill for 1 hour, and the activated carbon powder had particles with D1 having a 10 mesh size, D2 having a 17 mesh size, D3 having a 28 mesh size, h1/h2 being 0.35, and h2/h3 being 0.65. Size distribution was confirmed. The iodine adsorption amount of the activated carbon powder was 1053 mg/g.

(Production Example 3)

100 g of polyvinyl alcohol (PVA) pellets were placed in a 5L glass flask, 1700 mL of water was added, and the mixture was stirred at room temperature for 24 hours. The polyvinyl alcohol adhesive melted by stirring was aged at room temperature for 24 hours to prepare a polyvinyl alcohol adhesive solution with a solid content of about 6%.

(Production Example 4)

With respect to 100 parts by weight of the red clay powder, 0.5 parts by weight of the charcoal powder prepared in Preparation Example 1 and 0.5 parts by weight of the activated carbon powder prepared in Preparation Example 2 were added to a polysaccharide-containing aqueous solution containing 5% by weight of sucrose. Afterwards, composite particles (100) were manufactured by irradiating for 2 hours while maintaining a frequency range of 50 kHz to 55 kHz using an ultrasonic horn. Afterwards, the aqueous solution containing the composite particles 100 was dried for one day by applying hot air at 70 to 80° C. to evaporate the solvent, thereby obtaining a red clay mixed powder.

[Example 1]

As shown in Figure 1, red clay powder produced in the Sancheong region was purchased and prepared, and the moisture content was naturally dried to about 7 to 10% and then subjected to a screen process to prepare red clay powder with a particle size of 5 mm or less. In addition, the charcoal powder prepared in Preparation Example 1 and the activated carbon powder prepared in Preparation Example 2 were prepared. Next, 0.5 parts by weight of the charcoal powder and 0.5 parts by weight of the activated carbon powder were mixed with 100 parts by weight of the red clay powder to obtain a red clay mixture powder. Thereafter, 150 parts by weight of the polyvinyl alcohol adhesive solution prepared in Preparation Example 2 was added to 100 parts by weight of the red clay mixed powder and mixed for 3 hours to prepare a mixed solution (S100). Next, a molding additive containing 1600 parts by weight of colloidal silica, 20 parts by weight of silane, 10 parts by weight of organic acid, and 10 parts by weight of an anti-adhesion agent was added to the mixed solution and mixed for further 1 hour to obtain a mixed solution. was prepared (S150). Finally, the mixed solution mixed above was injected into a wood mold with one side open and cured at room temperature for one day to prepare a red clay board for reducing radon emission (S200). An actual photograph of the red clay board for reducing radon emission is shown in Figure 4.

[Example 2]

It was prepared in the same manner as in Example 1, except that 170 parts by weight of polyvinyl alcohol adhesive was added instead of 150 parts by weight.

[Example 3]

It was prepared in the same manner as in Example 1, except that 200 parts by weight of polyvinyl alcohol adhesive was added instead of 150 parts by weight.

[Example 4]

In Example 1, it was prepared in the same manner except that the red clay mixture powder prepared in Preparation Example 4 was added.

[Example 5]

It was prepared in the same manner as in Example 1, except that a molding additive containing 400 parts by weight of colloidal silica, 41 parts by weight of silane, 3 parts by weight of organic acid, and 3 parts by weight of an anti-adhesion agent was added to 100 parts by weight of the red clay mixed powder.

[Example 6]

It was prepared in the same manner as in Example 1, except that a molding additive including 300 parts by weight of colloidal silica, 50 parts by weight of silane, 3 parts by weight of organic acid, and 3 parts by weight of an anti-adhesion agent was added to 100 parts by weight of the red clay mixed powder.

[Example 7]

It was prepared in the same manner as in Example 1, except that a molding additive including 167 parts by weight of colloidal silica, 33 parts by weight of silane, 2 parts by weight of organic acid, and 2 parts by weight of an anti-adhesion agent was added to 100 parts by weight of the red clay mixed powder.

(Comparative Example 1)

It was prepared in the same manner as in Example 1, except that 130 parts by weight of polyvinyl alcohol adhesive was added instead of 150 parts by weight.

(Comparative Example 2)

It was prepared in the same manner as in Example 1, except that 250 parts by weight of polyvinyl alcohol adhesive was added instead of 150 parts by weight.

(Comparative Example 3)

It was prepared in the same manner as in Example 1, except that a molding additive containing 133 parts by weight of colloidal silica, 67 parts by weight of silane, 2 parts by weight of organic acid, and 2 parts by weight of an anti-adhesion agent was added to 100 parts by weight of the red clay mixed powder.

(Comparative Example 4)

It was prepared in the same manner as in Example 1, except that a molding additive including 100 parts by weight of colloidal silica, 100 parts by weight of silane, 2 parts by weight of organic acid, and 2 parts by weight of an anti-adhesion agent was added to 100 parts by weight of the red clay mixed powder.

(Comparative Example 5)

It was prepared in the same manner as in Example 1, except that a molding additive containing 57 parts by weight of colloidal silica, 100 parts by weight of silane, 2 parts by weight of organic acid, and 2 parts by weight of an anti-adhesion agent was added to 100 parts by weight of the red clay mixed powder.

(Comparative Example 6)

It was prepared in the same manner as in Example 1, except that a molding additive containing 22 parts by weight of colloidal silica, 80 parts by weight of silane, 2 parts by weight of organic acid, and 2 parts by weight of an anti-adhesion agent was added to 100 parts by weight of the red clay mixed powder.

(Comparative Example 7)

It was prepared in the same manner as in Example 2, except that a mixture of 0.1 part by weight of the charcoal powder and 0.1 part by weight of the activated carbon powder was used based on 100 parts by weight of the red clay powder.

(Comparative Example 8)

It was prepared in the same manner as in Example 2, except that a mixture of 1.5 parts by weight of the charcoal powder and 1.5 parts by weight of the activated carbon powder was used based on 100 parts by weight of the red clay powder.

(Experimental Example 1)

<Mixability and bending strength evaluation>

Viscosity evaluation, gelation evaluation, and miscibility evaluation were performed on the mixed solutions to which molding additives were added in Examples 1 to 7 and Comparative Examples 1 to 6, and the radon prepared in Examples 1 to 7 and Comparative Examples 1 to 6 were evaluated. Bending strength evaluation was performed on the red clay board for emission reduction and is listed in Table 2 below.

viscosity gelation Mixability bending strength Example 1 ◎ ○ ◎ 3.9 Example 2 ◎ ◎ ◎ 4.3 Example 3 ◎ ◎ ◎ 4.2 Example 4 ◎ ◎ ◎ 4.5 Example 5 ◎ ◎ ◎ 4.1 Example 6 ◎ ◎ ◎ 4.1 Example 7 ○ ◎ ◎ 3.9 Comparative Example 1 Ⅹ Ⅹ Ⅹ 2.7 Comparative Example 2 Ⅹ Ⅹ △ 2.5 Comparative Example 3 X ○ ○ 3.0 Comparative Example 4 X △ △ 2.7 Comparative Example 5 X X X 2.5 Comparative Example 6 X X X 2.3

Excellent: ◎, Good: ○, Insufficient: △, Poor: Ⅹ

(Experimental Example 2)

<Radon radiation measurement>

First, a chamber was made using wood to measure radioactivity. The chamber used in the experiment was manufactured with a size of 30 cm in width and height, and a lid that allows the radon meter to be freely inserted and removed was installed inside the chamber. The radon measurement chamber manufactured in this way is shown in Figure 5.

First, a gypsum board was installed on one side of the chamber, and radon radiation was measured over time. When measuring radon radioactivity, radon radioactivity was measured using a radon meter, Radon Eye (model name), manufactured by FT Lab Co., Ltd., and the specifications of the radon meter used are listed in Table 3 below.

Measurement value display Measurement temperature Measurement sensitivity Measuring range measurement error 10 minute intervals 10~40℃ 0.5 pCi/l 0.1 to 99 pCi/l <±10%

Next, the red clay board for reducing radon emission with a thickness of 0.5 cm prepared in Examples 1 to 3, Comparative Examples 1 to 2, and Comparative Examples 7 to 8 was installed on the inner wall of the chamber, and then placed in the central part of the chamber. A gypsum board was installed on one side of the interior, and a radon meter was placed outside the chamber to measure radon radiation over time, and the results are listed in Table 4 below.

Gypsum board Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative example 2 Comparative example 7 Comparative example 8 5 minutes 1.05 0.68 0.62 0.65 0.48 0.95 One 0.95 0.87 2 hours 1.26 0.89 0.81 0.85 0.62 1.13 1.2 1.25 1.13 4 hours 1.35 0.84 0.76 0.8 0.59 1.22 1.28 1.18 1.06 6 hours 1.32 0.79 0.72 0.76 0.55 1.19 1.25 1.11 1.01 8 hours 1.26 0.67 0.61 0.64 0.47 1.13 1.2 0.94 0.83 10 hours 1.41 0.79 0.72 0.76 0.55 1.27 1.34 1.11 1.01 12 hours 1.63 0.59 0.54 0.57 0.41 1.47 1.55 0.83 0.78 14 hours 1.85 0.87 0.79 0.83 0.61 1.67 1.76 1.22 1.11 16 hours 2.52 0.9 0.82 0.86 0.63 2.27 2.39 1.26 1.15 18 hours 2.3 1.14 1.04 1.09 0.80 2.07 2.19 1.60 1.46 20 hours 2.26 1.45 1.32 1.39 1.02 2.03 2.15 2.03 1.85 22 hours 2.41 1.58 1.44 1.51 1.11 2.17 2.29 2.21 2.02 24 hours 2.04 1.74 1.58 1.66 1.22 1.84 1.94 2.44 1.98

In Table 4 above, the unit of radioactivity is pCi/l.

As can be seen in Table 4, it can be seen that Examples 1 to 4 according to the present invention have the best radon radiation reduction performance compared to the comparative example.

As described above, the present invention has been described with specific details, limited embodiments, and drawings, but these are provided only to facilitate a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention Anyone skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described below as well as all modifications that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

S100: mixing stage
S150: mixing stage
S200: Forming step
100: composite particle
110: Particles of red clay powder
120: Particles of charcoal powder
130: Particles of activated carbon powder

Claims (5)

Adding and mixing a polyvinyl alcohol adhesive to a red clay mixed powder mixed with 0.1 to 1 part by weight of charcoal powder and 0.1 to 1 part by weight of activated carbon powder based on 100 parts by weight of red clay powder (S100);
Including the step of injecting and molding the mixed liquid into a wood mold (S200),
The polyvinyl alcohol adhesive liquid has a solid content of 5 to 10% by weight,
The red clay board for reducing radon emission is a method of manufacturing a red clay board for reducing radon emission comprising 150 to 200 parts by weight of the polyvinyl alcohol adhesive based on 100 parts by weight of the red clay mixed powder.
delete According to clause 1,
The red clay mixed powder is
The red clay powder, charcoal powder, and activated carbon powder are added to the polysaccharide-containing aqueous solution, and the added aqueous solution is irradiated with ultrasonic waves using an ultrasonic horn and dried, so that the particles of the red clay powder are used as central particles to form the above particles on the surface of the red clay powder particles. A method of manufacturing a red clay board for reducing radon emissions, which is a composite powder in which particles of charcoal powder and particles of the activated carbon powder are alternately arranged.
According to clause 1,
Between the mixing step (S100) and the forming step (S200),
It includes adding and mixing a molding additive to the mixed solution (S150),
The molding additive is
A method for producing a red clay board for reducing radon emissions, comprising 160 to 1600 parts by weight of colloidal silica, 20 to 50 parts by weight of silane, 2 to 10 parts by weight of organic acid, and 2 to 10 parts by weight of an anti-adhesion agent based on 100 parts by weight of the red clay powder.
Red clay board for reducing radon emissions manufactured by the manufacturing method according to any one of paragraphs 1, 3, and 4.