TW201442979A - Molded body for structure construction and molded body for structure construction manufacturing method and ceramic body manufacturing method - Google Patents

Abstract

To present a molded body for structure construction such as a brick or a tile and the like and is a molded body for structure construction brick that is suitable for use for the construction of radiation shielding structures. A molded body for structure construction in which by firing clay into which ferrite powder has been mixed included at a proportion of 60 wt% after being formed into a specified shape, the density after firing has been made 3.5 g/cm<SP>3</SP> and the radiation shielding effect has been enhanced is obtained. It is preferable that press molding be carried out with the previously mentioned molding material and the compression strength of the molded body for structure construction made 100 MPa or greater. In addition, for the ferrite powder, it is preferable that one that is expressed by the compositional formula: AO.nX2O3 (however, it should be noted that in said compositional formula, A is one type or more of an element selected from among Mg, Ca, Mn, Co, Ni, Cu, Sr, Ba, or Pb, X is one type or more of an element selected from among Fe, Co, or Ni, and n is a mol ratio that is defined as an integer from 1 to 9) be used.

Description

Molded body for structural building, manufacturing method thereof and ceramic body manufacturing method

The present invention relates to a shaped body for a structural building such as brick or tile, and in particular to a shaped body for a structural building suitable for constructing a radiation shielding structure effect, and a shaped body for a structural building Manufacturing method.

Insufficient temporary storage facilities for wastes that have been contaminated with radioactive materials have become a problem after nuclear power plant accidents. It is desirable to shield the radiation emitted by the waste by surrounding the temporary storage facility for the waste contaminated with the radioactive material by a wall formed of high density concrete. However, when forming a wall with concrete, the following series of operations are required: (1) setting the template, (2) arranging the steel bars in the template, (3) pouring the concrete into the template, and (4) solidifying the concrete. And (5) remove the template and the problem requires work, time and cost. In addition, the problem is that the appearance of concrete is cold and boring. These issues are one of the reasons for the lack of progress in the construction of temporary storage facilities for wastes that have been contaminated with radioactive materials.

In contrast to this, an advantage of a shaped body such as a brick, a tile or the like for a structural building is, for example, the fact that the construction can be carried out by laying only one shaped body on top of the other shaped body, or by The molded bodies are simply bonded together, and the appearance after construction is good, and the molded bodies are widely used. However, since the density of the shaped body used for the structural building is generally low (about 2.2 g/cm ³ ), it is expected that the radiation shielding effect as the outer casing of the above temporary storage facility may be unsatisfactory. For example, if bricks are to be used to make the outer casing of a temporary storage facility, it is necessary to stack multiple layers of bricks or to increase the thickness of each individual brick, and in fact, there is a risk of increased costs. Forming systems for structural buildings, such as bricks, which have a high density and have a strong radiation shielding effect, are advantageous, but such articles have not been found.

Incidentally, a technique for increasing the density and enhancing the radiation shielding effect by including ferrite for concrete or the like has been proposed (for example, refer to Patent References 1 and 2). Ferrite system A magnetic material containing iron oxide and widely used in various electronic components, such as motor magnets, toner cartridges for photocopiers and laser printers, magnetic disks, magnetic tapes, and the like. In the case of the radiation shielding materials of Patent References 1 and 2, attention is paid mainly to high density (radiation shielding effect). However, Patent Recommendations 1 and 2 do not enumerate the contents including ferrite in a molded body such as a brick for a structural building, and this suggestion is not even made. The commonality of the shaped body and concrete used for structural buildings such as bricks is that both are used as building materials, but the production method (specifically, the presence or absence of firing), materials (composition), templates, The construction methods are different, and they are completely different things.

Further, in Patent Reference 3, it has been proposed to laminate and fire a plurality of bricks or tiles containing ferrite-containing ceramic materials. However, the brick of Patent Reference 3 does not pay attention to the density due to ferrite, but focuses on the electromagnetic characteristics of ferrite, and does not exceed the goal of shielding electromagnetic waves emitted by mobile phones and personal computers. In other words, the content of increasing the density of bricks or tiles and enhancing the radiation shielding effect is not cited in Patent Reference 3, and even this suggestion is not made.

Prior technical references Patent reference

<Patent Reference 1> Japanese Patent Application Publication (Kokai) No. 57- 016397

[(Page 2, upper right column, columns 8 to 15, and page 2, bottom right column, columns 16 to 20)]

<Patent Reference 2> Japanese Patent Application Publication (Kokai) No. 2002-26779

(Scope of application for patents)

<Patent Reference 3> Japanese Patent Application Publication (Kokai) 2008-094066

(Scope of application for patents, and paragraphs 0002, 0005, 0030 and 0033)

The present invention is intended to solve the above problems and to present a molded body for a structural building such as a brick or a tile, and is applicable to a molded body for a structural building in which a radiation shielding structure is constructed. In particular, the object of the present invention is to provide a shaped body for a structural building which has a high density, exhibits an excellent radiation shielding effect, and has high strength. In addition, the object of the present invention is to easily construct a radiation shielding structure in a short period of time and to minimize construction costs. In addition, the object of the present invention is to improve the appearance of the constructed radiation shielding structure and the environment in which the radiation shielding structure is maintained. Further, the object of the present invention is to provide a method of manufacturing the above-described molded body for a structural building.

The above problem is solved by presenting a shaped body for a structural building characterized by the density after firing (the apparent porosity of the refractory brick by "JIS R2205-1992" , the density of the vacuum method in the measurement method for the apparent porosity, coefficient of water absorption, and specific gravity of a fire resistant brick, wherein the diamond is cut after firing The knife cuts the sample for the shaped body of the structural building into 100 mm L, 100 mm W and 100 mm H; hereinafter referred to as "the overall density of the formed body after firing"; the same in the following description of the specification) is 3.5 g /cm ³ or more and has been enhanced by forming a shaped material containing ferrite powder in a ratio of 60 wt% or more to form a prescribed shape, and to enhance the radiation shielding effect; and presenting the structure for a structural building A method of producing a shaped body. In the present context, the "formed body for a structural building" is not cast on the spot such as concrete, but is a material for a structural building which has been previously formed in a prescribed shape. Examples of shaped bodies that can be used for structural buildings are those such as bricks and tiles, which are used to form shield structures such as walls, ceilings, floors, etc. by stacking, assembling and bonding a plurality of individual articles.

By including the ferrite powder and firing in this manner, it is possible to increase the overall density of the formed body after firing and to provide a molded body for a structural building exhibiting an excellent radiation shielding effect. Therefore, it is possible to easily construct a radiation shielding structure for shielding radiation in a short period of time, for example, a structure surrounding a temporary storage facility for waste that has been contaminated by radioactive materials or the like. In addition, the appearance of the constructed structure may have an atmosphere and is unobtrusive. Furthermore, as previously discussed, ferrite is employed in a variety of electronic components. Therefore, ferrite containing ferrite in the manufacturing process or disposal process and the ferrite collected from the waste can be used as a raw material, thereby promoting efficient use of the waste.

In the molded body for a structural building of the present invention and a method of manufacturing the same, the previously mentioned formed body is preferably press-formed, and the compressive strength of the formed body obtained for the structural building is preferably 100. MPa or higher. Thereby, the strength of the formed body for the structural building is further improved, and it is possible to construct a structure superior in strength such as shock resistance. In addition, the radiation shielding effect can also be enhanced. The compressive strength of the shaped body for a structural building containing ferrite powder in a ratio of 60 wt% or more in the present invention can be further increased to 160 MPa or more. In addition, as will be discussed below, the press-forming strength can be further increased to 200 MPa or higher, 250 MPa or higher, and 300 MPa or higher. In contrast, the compressive strength of a general shaped body for a structural building which does not contain ferrite is 35 MPa to 50 MPa. As will be discussed below, shaped bodies for structural buildings The higher the compressive strength, the greater the overall density of the formed body after firing, and the stronger the radiation shielding effect. There is no specific upper limit on the compressive strength of the shaped body used for the structural building, but in reality, it is about 400 MPa to 500 MPa.

The type (composition formula) of the ferrite powder in the molded body for a structural building and the method for producing the same according to the present invention is not particularly limited as long as the overall density of the formed body after firing can be 3.5 g/cm ³ or Larger, but the composition used is usually expressed as a composition: AO‧nX ₂ O ₃ .

However, it should be noted that in the composition formula mentioned above, n is defined as a molar ratio of an integer of 1 to 9.

Further, in the composition formula mentioned above, A is one or more types of elements selected from the group consisting of magnesium (Mg), calcium (Ca), manganese (Mn), cobalt (Co), and nickel (Ni). Copper (Cu), strontium (Sr), barium (Ba) or lead (Pb), but specifically, one or more types of elements selected from the group consisting of Sr, Ba or Pb are preferred. This is because the number of atoms (mass) of Sr, Ba, and Pb is larger than other elements and these elements exhibit better radiation shielding effects.

Further, in the composition formula mentioned above, X is one or more types of elements selected from the group consisting of iron (Fe), cobalt (Co) or nickel (Ni), but Fe is particularly preferred. The cost of Fe is lower than that of Co or Ni and is practical.

In the molded body for a structural building of the present invention and the method of manufacturing the same, the type of the forming material mixed with the ferrite powder is not particularly limited as long as the material can be used as a raw material for a molded body of a structural building. . For clays, one having one or more types of oxides selected from the group consisting of alumina (Al ₂ O ₃ ), cerium oxide (SiO ₂ ) or boron oxide (B ₂ O ₃ ) is exemplified. Specifically, kaolin (Al ₂ Si ₂ O ₅ (OH) ₄ ), halloysite (Al ₂ Si ₂ O ₅ (OH) ₄ ‧2H ₂ O), or the like can be given as an example.

Further, regarding the firing temperature of the molded body for a structural building of the present invention, the firing time of the molded body for the structural building, and the manufacturing method thereof, the parameters are different depending on the type of the forming material and The type of ferrite powder mixed with the material, and The balance between the firing temperature and the firing time, and the like, and is not specifically limited. However, when considering the melting point of the ferrite contained in the formed body for the structural building and the strength of the formed body for the structural building, the firing temperature of the formed body for the structural building is usually set. It is from 1,000 ° C to 1,400 ° C and the firing time is usually set to 50 hours to 150 hours.

Further, the particle diameter of the ferrite powder in the molded body for a structural building and the method for producing the same according to the present invention is not particularly limited. However, considering the convenience of ferrite powder production, the convenience of mixing ferrite powder with clay, and the formability of clay after mixing with ferrite powder, the particle diameter of the ferrite powder is usually 0.5 μm to 8 mm. Surprisingly, within this range, a fine particle diameter between 0.5 μm and 20 μm results in the highest specific gravity of the fired ceramic body even if it contains 95% by weight of the ceramic body, without cracking or dimensional accuracy. problem. These results are contrary to the teachings of the ceramic industry, which emphasize the extreme importance of using a broadly mixed distribution of particle sizes in ceramic bodies. See, eg, Easy to Understand Industrial Ceramics, first 99-102 / 516; Author: Youichi Shiraki; Publisher: Gihodo Shuppan Co., Ltd., 1-3-6, Akasaka, Minato Ward, Tokyo, 1969 Nian 6 30th.

As discussed above, in accordance with the present invention, for shaped bodies such as bricks or tiles for structural buildings, it is possible to present shaped bodies for structural buildings that are suitable for use in constructing radiation shielding structures. In particular, it is possible to present a shaped body for a structural building in which the overall density of the shaped body after firing is high, and it not only exhibits an excellent radiation shielding effect, but also exhibits high strength. In addition, the radiation shielding structure for shielding radiation can be easily constructed in a short period of time, and the construction cost can also be minimized. In addition, it is possible to improve the appearance of the environment in which the radiation shielding structure has been constructed and to maintain the environment of the radiation shielding structure. Further, the above-described manufacturing method of the molded body for a structural building can also be exhibited.

An overview of the brick of the present invention and its method of manufacture.

A further specific explanation will be given regarding a preferred embodiment of the shaped body for a structural building of the present invention and a method of manufacturing the same. The forming system for a structural building of the present invention is produced by the following processes: (1) a forming material forming process in which a forming material containing ferrite powder is contained in a ratio of 60 wt% or more, and (2) a forming process, The molding material obtained in the molding material production process is formed into a prescribed shape, and (3) a firing process in which the molding material is formed into a prescribed shape in the molding process.

A shaped body for a structural building can be prepared, which has a bulk density of 3.5 g/cm ³ or more after firing, which is significantly higher than that of a conventional formed body for structural buildings. The bulk density of the body (about 2.2 g/cm ³ ) and exhibits excellent radiation shielding effects.

Incidentally, radiation is classified into particle radiation (for example, alpha (α) ray, beta (beta) ray, neutron ray, etc.) and electromagnetic waves (for example, gamma (γ) according to the form of propagation, wavelength (energy), source of generation, and the like. ) Ray, X-ray, etc.). The shaped bodies for structural buildings using the present invention may shield all of the radiation given above, but it has been assumed that especially gamma rays and X-rays having strong penetrability are shielded. Since gamma rays and X rays do not have electric charges and are electrically neutral, it is impossible to weaken them by electromagnetic interaction. For shielding of gamma rays and X-rays, the use of high-density materials is essential and the shaped bodies of the present invention for structural buildings can exhibit excellent effects on shielding gamma rays and X-rays.

A detailed explanation of a preferred embodiment of the shaped body for a structural building and a method of manufacturing the same according to the present invention will be given hereinafter in the order of the processes described above. In the following explanation, for the sake of convenience, an example of a case where a brick is produced as a formed body for a structural building will be described. The description is made, but the method of modeling the examples can be used to create other shaped bodies such as tiles for structural buildings.

Forming material production process

The forming material production process produces a process comprising a 60 wt% ferrite powder forming material. In a preferred embodiment of the invention, the process becomes a mixing process in which the shaped material is produced by adding clay to the ferrite powder and mixing. For the ferrite powder, it is used after mixing iron oxide (Fe ₂ O ₃ ) and various additives with materials such as strontium carbonate (SrCO ₃ ), barium carbonate (BaCO ₃ ) and granulating and firing, crushing and pulverizing. article. In addition, spherical clay is used, which is a type of kaolin.

In the preferred embodiment, the proportion of the mixture of the ferrite powder is not particularly limited as long as the ratio is 60 wt% or more. However, it is preferable to make ferrite in consideration of increasing the overall density of the formed body after firing of the formed body for the structural building and enhancing the radiation shielding effect thereof and the strength of the formed body for the structural building. The proportion of the mixture of bulk powders is as high as possible. Specifically, the proportion of the mixture of the ferrite powder is preferably 70 wt% or more, more preferably 80 wt% or more, and even more preferably 85 wt% or more. On the other hand, if the proportion of the ferrite powder mixture is too high, the proportion of the mixture of the plastic material which is effectively formed, such as clay, is inevitably lowered, and the plasticity of the forming in the unfired state is lowered, and it becomes difficult to make The shaped material forms a specified shape. Therefore, in the case of mixing with a plastic material such as clay, the mixture ratio of the ferrite powder is 97 wt% or less. However, it should be noted that when a binder such as an organic binder is used and the ferrite powder is bonded, it may be formed without mixing in clay or the like. Therefore, in the case where they use a binder, the proportion of the mixture of ferrite powders may be higher than the above. In particular, the proportion (content) of the mixture may be 100% or may be close to 100% without limitation.

In addition, the ferrite powder mixed into (included in) the shaped material as discussed above is typically made to have a particle diameter of from 0.5 μm to 8 mm. However, if the particle diameter of the ferrite powder is too small, it takes time and effort to crush. Therefore, it is preferred to make the particles of the ferrite powder The diameter is 1 μm or more, more preferably 2 μm or more, and even more preferably 3 μm or more. On the other hand, if the particle diameter of the ferrite powder is too large, there is a risk that the molding material to which the powder is added will become difficult to form. In addition, it may also be difficult to uniformly mix in the ferrite powder. Therefore, it is preferred that the ferrite powder has a particle diameter of 8 mm or less, more preferably 4 mm or less, and even more preferably 2 mm or less. In a preferred embodiment of the invention, the ferrite powder has a particle diameter of from 0.5 μm to 20 μm and an average of about 5 μm. It has been unexpectedly found that within these ranges, a pre-fired ceramic system comprising 60% or more (by weight) particles between 0.5 μm and 20 μm is feasible and has the highest specific gravity. See below the effect of the ferrite particle size distribution on the specific gravity of the fired ceramic composite A-D. In addition, they are best included with ferrites having an average particle diameter between 3 microns and 600 microns, including 3 microns and 600 microns. Thus, in a preferred embodiment, the ceramic body comprises ferrite powder and at least 60% of the ceramic body weight, more preferably at least 70% by weight, more preferably at least 80% by weight, more preferably at least 90% Its weight and optimally at least 95% of its weight is attributed to particles between 0.5 μm and 20 μm in size. Although less desirable, a relatively narrow mixture having a particle size between 0.5 μm and 600 μm may advantageously comprise at least 60%, more preferably at least 70%, more preferably at least 80%, more preferably at least 90% by weight of the ceramic body. % and best at least 95%. The average ferrite particle diameter is preferably between 3 microns and 600 microns (including 3 microns and 600 microns). The resulting fired ceramic body preferably has a compressive strength greater than 150 MPa and a density greater than 3.5 g/cm 3 .

If the waste material obtained in the manufacture of products containing ferrite (electronic components such as motor magnets, toner cartridges for photocopiers and laser printers, magnetic disks, magnetic tapes, etc.) is used for ferrite powder, Or when the waste generated in the disposal of these products is used for ferrite powder, the effective use of waste can be planned.

2. Forming process

When the above-described forming material production process has been completed, the forming process is subsequently performed. The forming process is such that the ferrite powder has been mixed in the forming process (mixing process) of the forming material. The process by which a shaped material forms a specified shape. The molding material forming method is not particularly limited, but is preferably carried out by press forming using a press. At this time, if press forming is performed under vacuum (under reduced pressure; vacuum pressing), the formed material will be densified, and the overall density of the formed material will further after the fired shaped material (formed body for the structural building). Increased, and it is possible to obtain a shaped body for a structural building exhibiting a better radiation shielding effect. In addition, it is possible to further increase the compressive strength of the formed body obtained for the structural building.

The shape and size of the formed material are measured in an appropriate manner according to the application of the molded body for a structural building or the like. For example, when a shaped body for a structural building is used as a brick or the like, examples which may be given include a regular parallelepiped (including a cube or a quadrangular plate), a cylinder (including a disk), and combinations thereof. Shape and so on. Further, in the case where the shaped bodies for structural buildings are used as tiles, floors, ceilings or roofing materials (roof tiles, etc.), examples which may be given include thick plates or curved profiles. In the case where they are expected to be inserted through the inside of the formed body for the structural building, through holes or grooves for penetrating the reinforcing bars or screws or the like may be formed. The design of the shaped body for a structural building (e.g., formation of a patterned indentation, etc.) can be applied to the surface of the shaped material after forming. In this way, the shape of the shaped material can be determined in an appropriate manner according to the application of the formed body for the structural building or the like.

3. Burning process

When the above forming process has been completed, the firing process is subsequently performed. The firing process is a process of firing a shaped material that has been formed into a specified shape during the forming process. As discussed above, the firing temperature of the shaped material is typically from 1,000 ° C to 1,400 ° C. However, if the firing temperature of the forming material is made too low, and the shaped material may not be satisfactorily burned and the forming material (formed body for the structural building) will be easily broken after firing. Therefore, it is preferred that the molding material has a firing temperature of 1,100 ° C or higher and more preferably 1,200 ° C or higher. On the other hand, if the firing temperature of the molding material is too high, there is a risk that the clay or ferrite powder contained in the molding material will melt and the shape of the molding material will not be maintained. Therefore, it is better to make The firing temperature of the shaped material is 1,350 ° C or lower. In a preferred embodiment of the invention, the molding material is fired at 1,280 ° C (about 1,300 ° C).

In addition, as discussed above, the firing time of the shaped material is typically from 5 hours to 150 hours. However, if the firing time of the forming material is too short, it may be unsatisfactory to fire the shaped material and the forming material (formed body for the structural building) will be easily broken after firing. Therefore, it is desirable to subject the molding material to a firing time of up to 10 hours or longer, 30 hours or longer, or 50 hours or longer. It is preferred that the molding material has a firing time of 60 hours or longer, more preferably 70 hours or longer, and most preferably 80 hours or longer. On the other hand, if the firing time of the molding material is too long, there is a risk that the shrinkage due to firing will become strong and the dimensional accuracy will be lowered. Therefore, it is preferred that the molding material has a firing time of 150 hours or less, and more preferably 130 hours or less. In a preferred embodiment of the invention, the firing time of the forming material (from the time of insertion into the firing furnace (tunnel kiln) until removal) is 120 hours.

4. Complete

When the above-described firing process has been completed, the formed body for the structural building is completed. The molding material for the formed body of the structural building has an overall density after firing of 3.5 g/cm ³ or more and is significantly higher than that of a molded body for a structural building such as ordinary brick. Therefore, the formed body for a structural building of the present invention can exhibit an excellent radiation shielding effect as compared with a conventional formed body for a structural building. Further, the strength of the formed body for a structural building of the present invention is higher than that of a conventional formed body for a structural building.

The overall density of the forming material preferably used for the shaped body of the structural building is as high as possible after firing to further enhance the radiation shielding effect and strength of the shaped body obtained for the structural building. Specifically, the bulk material used for the molded body of the structural building preferably has a bulk density after firing of 3.8 g/cm ³ or more, more preferably 4.0 g/cm ³ or more, or even more preferably 4.2 g/cm ³ or more, even more preferably 4.3 g/cm ³ or more, even more preferably 4.4 g/cm ³ or more, and most preferably 4.5 g/cm ³ or more. In the formed body for the structural building of Working Example 7 discussed below, the bulk density of the shaped material after firing was 4.58 g/cm ³ . If a solution such as vacuum pressing as discussed above is applied to the forming of a shaped body for a structural building, it is possible to make the overall density of the shaped material after firing greater than the overall density. On the other hand, the upper limit of the overall density of the molding material for the molded body of the structural building after firing is not particularly limited, but unless the material having a density larger than that of the ferrite powder is mixed into the molding material, it is impossible to make the density It is larger than the density of the ferrite powder (generally, about 4.6 g/cm ³ to 5.1 g/cm ³ ).

Working example 5. Assessment of the effectiveness of radiation shielding

The molded articles for structural buildings of Working Examples 1 to 9 and the molded bodies for structural buildings of Comparative Examples 1 and 2 were manufactured to investigate the radiation shielding effect of the molded body for structural buildings of the present invention. At the same time, the shaped bodies for the structural buildings of Comparative Examples 3 and 4 were obtained and the effectiveness of the radiation shielding effectiveness was evaluated for each of the individual shaped bodies for the structural building. For the molded bodies for structural buildings of Working Examples 1 to 9 and Comparative Examples 1 and 2, 锶‧ ferrite (SrO‧6Fe ₂ O ₃ ), 钡‧ ferrite were combined as shown in Table 1 below. (BaO‧6Fe ₂ O ₃ ), spheroidal clay (kaolin), boric acid (B(OH) ₃ ), N3 (wherein the forming material comprising a mixture of crushed fired clay and raw clay is pressed and fired) Article; composition of 64 wt% cerium oxide (SiO ₂ ), 32 wt% alumina (AL ₂ O ₃ ) and 2 wt% iron (III) oxide (Fe ₂ O ₃ )) and chromite (FeCr ₂ O) ₄ ) After the molding material of manganese (Mn) has been press-formed, it is fired at a firing temperature of 1,280 ° C for 120 hours.

In addition, in Table 1 below, the underlined numbers indicate their off-line percentages. In addition, in the "pressing conditions" in Table 1 below, "A" means "50 t suppression (1 implementation)", "B" means "150 t suppression (1 implementation)", "C" means " 300 t suppression (8 implementations), and "D" means "300 t suppression (6 implementations)". For 50 t pressing, use Mitsuishi Fukai Iron Works Co., Ltd. tubular pressing system (model: PS70), for 150 t pressing, use Mitsuishi Fukai Iron Works Co., Ltd. friction pressing system (model: F150T), and for 300 t pressing, use Mitsuishi Fukai Iron Works Co., Ltd. Vacuum press (model: CFOP-1E). For press forming, all were used with 230 mm L x 114 W x H (variable with powder filling volume). Therefore, the pressing pressure became about 18.7 MPa in the case of 50 t pressing, about 56 MPa in the case of 150 t pressing, and 112 MPa in the case of 300 t pressing.

As a molded body for a structural building which was not typed in Comparative Examples 3 and 4 in Table 1 below, a general commercial brick (a brick containing no ferrite) for the forming system of the structural building of Comparative Example 3 was compared, and Comparative Example 4 A commercially available cement brick (a ferrite-free cement brick) for a forming system of a structural building. For reference purposes, the component fractions of 锶‧ ferrite in Table 1 mentioned above were measured using a Rigaku X-ray fluorescence spectrometer (model: ZSX100e) and entered in Table 2 below. Further, the bulk density of the molded articles for structural buildings of Working Examples 1 to 9 and the molded articles for the molded articles of Comparative Examples 1 to 4 after firing were shown in Table 3 below. in. For the compression density in Table 3 below, the pressure resistance tester (No. 212445) of Tokyo Testing Machine Co., Ltd. was used and according to the "fire resistant brick compression strength test method" of JIS R2206 Conduct measurement. Referring to and comparing the following Tables 1 and 3, the overall density of the formed material after firing becomes larger as the pressing pressure at the time of forming the formed material becomes larger, and it is confirmed that the compressive strength also becomes large.

<Photosensitivity test>

First, the evaluation of the radiation shielding effect of the shaped bodies for structural buildings of Working Examples 1 to 3 and the shaped bodies for structural buildings of Comparative Examples 1 to 4 was carried out by means of the following photosensitivity test. That is, a radiation-sensitive film ("Industrial X-ray film IX100" manufactured by Fuji Film) was spread on the molded body for structural buildings of Working Examples 1 to 3 and Comparative Examples 1 to 4 for the structure. Measuring the sensitivity of each individual film on the bottom of each of the formed bodies of the building after irradiating each of the top surfaces of the shaped bodies for the structural building with radiation for a fixed period of time (monochrome The depth of black in the image). The working bodies for the structural buildings used in Working Examples 1 to 3 and Comparative Examples 1 to 4 used in the photosensitivity test were the same in size, and the thickness (thickness in the radiation penetration direction) was made uniform at 60 mm. For the measurement of the depth of black in the film, a densitometer ("Sakura Densitometer PDA-81" manufactured by Konica Minolta) was used. Two types of radiation are used, namely X-rays and gamma rays. The radiation source of gamma rays is ¹⁹² Ir. The stronger the radiation shielding effect of the shaped body used for the structural building, the less the amount of radiation reaching the film, and the film is not sensed (the color changes from white to black), so by the density measurement previously mentioned The depth is smaller. For the molded bodies for structural buildings of Working Examples 1 to 3 and the molded bodies for structural buildings of Comparative Examples 1 to 4, the depth of the film was irradiated with X-rays and γ-rays, respectively. The numbers are shown in Table 4 below.

However, it should be noted that the film depth value in Table 4a mentioned above is a dimensionless amount D, which can be calculated using Equation 1 given below. In Equation 1 below, L ₀ is the brightness (cd/m ² ) of the observation light used to irradiate the partially irradiated film from the observation light in the densitometer mentioned previously; and the L-system film reflects and is previously The brightness (cd/m ² ) of the reflected light received by the light receiver portion of the densitometer mentioned.

<expression 1>

D=log ₁₀ (L ₀ /L)... Equation 1

Referring to Table 4a mentioned above, in the case of comparing the molded bodies of the structural buildings without ferrite in Examples 3 and 4 by X-ray irradiation, the film depth was 4.5; and γ was used. In the case where the ray irradiation was the same as that of the molded articles for structural buildings of Comparative Examples 3 and 4, the film depth was 1.7. On the other hand, although the film depth (2.8 and 3.8) in the case of a molded body for a structural building of a given ferrite content of Examples 1 and 2 was compared by X-ray irradiation. The film depth (4.5) in the case of the molded bodies for structural buildings without the ferrites of Examples 3 and 4 was reduced to some extent, but the structures for Examples 1 and 2 were compared by gamma ray irradiation. The film depth (1.5) in the case of the formed body of the building hardly decreased from the case where the film depth (1.7) for the molded body of the structural building of Comparative Examples 3 and 4 was compared with γ-ray irradiation. From this fact, it can be understood that although the ferrite contents of Comparative Examples 1 and 2 were 10% and 25% as compared with the molded bodies for structural buildings containing no ferrite of Comparative Examples 3 and 4. The shaped bodies used in structural buildings determine a certain shielding effect for X-rays, but are determined to have almost no shielding effect on gamma rays.

In contrast, the film depth (0.4 to 0.7) in the case of the shaped bodies for structural buildings containing 87 wt% to 90 wt% of ferrite in Working Examples 1 to 3 was reduced by X-ray irradiation to About one-tenth of the film depth (4.5) in the case of the molded articles for structural buildings of Examples 3 and 4 which were irradiated with X-rays by X-ray irradiation. Further, the film depth (0.8 to 0.9) in the case of the molded body for structural buildings containing 87 wt% to 90 wt% of ferrite in Working Examples 1 to 3 was irradiated with gamma rays to be irradiated with gamma rays About half of the film depth (1.7) in the case of the molded body of the structural building without the ferrite of Comparative Examples 3 and 4. According to this fact, it is understood that the molded bodies for structural buildings containing 87 wt% to 90 wt% of ferrites of Working Examples 1 to 3 are compared with the molded bodies for structural buildings of Comparative Examples 3 and 4. A very good shielding effect is exhibited for both X-rays and gamma rays.

As shown below, multiple examples have significantly higher compressive strength than conventional ceramic bodies.

<γ-ray penetration test>

Subsequently, the radiation shielding effect of the shaped bodies for structural buildings of the above Working Examples 1 to 9 was evaluated by measuring the attenuation coefficient μ with the gamma ray penetration test. For the gamma ray penetration test, the 10 cm square plate test samples of the molded articles for the structural buildings of Working Examples 1 to 9 were each adjusted to a thickness of 1 cm. For the measurement device, a low background pure germanium semiconductor detector (Canberra GC 1520) manufactured by Canberra was used. The measurement results were analyzed by evaluating the integrated intensity of the spectrum using the line analysis software "wPK area 2006". For standard radiation sources, Cs-137 (8.10E+03 Bq) and Co-60 (4.32E+03 Bq) are used, which are the gamma ray standard radiation sources of the Japan Radioisotope Association. The values of the attenuation coefficient μ obtained using the gamma ray penetration test are shown in Table 5 below.

However, it should be noted that the values of the attenuation coefficients μ of Working Examples 1 to 9 in Table 5 above were calculated using Equation 2 below. In Equation 2, I ₀ is a count number in the case where measurement is performed in a state where a test sample containing a plate for a molded body of a structural building is not present, and I is included in Working Examples 1 to 9 The count number in the case where the test sample of each of the molded bodies of the structural building is in a state where the test sample is fixed in position. Further, x is the thickness (cm) of each of the test samples of the molded bodies for the structural buildings of Working Examples 1 to 9.

<expression 2>

μ=(1/x)log _e (I ₀ /I)... Equation 2

In addition, for reference purposes, use the "Handbook of Shielding Calculations for Radiation Facility" (author, editor and publisher: Legal Safety Technology Center, Law Concerning Prevention of Radiation Injury Due to Radioisotopes, Etc., Publishing and Editing Committee; printing And binding: Reference value cited in Sobunsha Co., Ltd., published March 2007). The attenuation coefficient of lead (total density of the formed body, 11.34 g/cm ³ ) calculated according to the calculation method cited in the reference is Comparative Example 5, and concrete (total density of the formed body, 2.1 g/cm ² [sic]) The attenuation coefficient is Comparative Example 6, and it is shown in [Sic] in Table 5 above.

Referring to Table 5 above, the following facts are determined: in all cases of "铯137 0.662 MeV", "Cobalt 60 1.173 Mev" and "Cobalt 60 1.332 Mev", the molded bodies for structural buildings of Working Examples 1 to 5 (In which the press forming was carried out by pressing at 50 t (1 time)), the molded body for the structural building of Working Example 6 (in which press forming was performed at 150 t (1 time)), Working Example 7 And a molded body for a structural building (in which press forming is performed by 300 t pressing (8 times)) and a molded body for a structural building of Working Example 8 (in which it is pressed at 300 t (6 times) The press forming is performed, the attenuation coefficient μ is larger and exhibits a better radiation shielding effect. Specifically, the fact that the total density of the formed body after firing is 4.3 g/cm ³ or more and the compressive strength is about 250 MPa or more is also applied to the structural building. The shaped body exhibited a more pronounced radiation shielding effect than the shaped bodies for structural buildings other than Working Examples 1 to 5. The shaped body for the structural building of Working Example 9 exhibits, in particular, a significant radiation shielding effect. Accordingly, in order to enhance the radiation shielding effect, it is desirable to increase the pressing pressure when forming the shaped material, thereby increasing the overall density and compressive strength of the shaped material after firing. Further, it was confirmed that although the radiation shielding effect of the molded articles for structural buildings of Working Examples 1 to 9 was weaker than that of metallic lead (Comparative Example 5), the effect was remarkably superior to that used as building materials in the construction of the radiation shielding structure. Concrete (Comparative Example 6).

6. Application

Regarding the shaped body for a structural building of the present invention, there is no particular limitation on its application, but as described above, since it exhibits an excellent radiation shielding effect, it may be used in an appropriate manner for applications requiring shielding radiation (construction) Radiation shielding structure (including buildings)). In particular, it can be used in an appropriate manner for shielding radiation having strong penetrating power such as X-rays, gamma rays, and the like. In addition, since the molded body for a structural building of the present invention can be easily constructed in a short period of time, it can be suitably used in an application requiring immediateness. For example, it may be used in a suitable manner as a shaped body for a radiation shielding structure building in which an outer casing structure for a temporary storage facility of waste that has been contaminated with radioactive materials is constructed. It is expected that by using the shaped body for a structural building of the present invention, the problem of insufficient temporary storage facilities for wastes contaminated with radioactive materials after a nuclear power plant accident can be solved.

Effect of particle size distribution on the specific gravity of fired ceramic body

A series of tests were performed to determine the effect of particle size distribution on the specific gravity of the fired ceramic body. Surprisingly, it was found that all ranges tested were feasible, but the best and smallest difference in particle distribution gave the best results.

a. Composite A

-0.6 mm Sr-ferrite grain: 47.5%

Average particle diameter (APD): 1.19 μm; range between 0.5 μm and 20 μm

Sr-ferrite powder: 47.5%

Spherical clay: 5%

Mecellose: 0.2%

Wood sulfonate: 0.5%

Water: 1.5%

b. Composite B

0.6-2.0 mm Sr.-ferrite grain: 47.5%

Sr-ferrite powder: 47.5%

Spherical clay: 5%

Mecellose: 0.2%

Wood sulfonate: 0.5%

Water: 1.5%

c. Complex C

2.0 mm Sr-ferrite grain: 47.5%

Sr-ferrite powder: 47.5%

Spherical clay: 5%

Mecellose: 0.2%

Wood sulfonate: 0.5%

Water: 1.5%

d. Complex D

Sr-ferrite powder: 95%

Spherical clay: 5%

Mecellose: 0.2%

Wood sulfonate: 0.5%

Water: 1.5%

Results: The specific gravity of the burned body is listed below.

Compound A: 4.15g/cm3

Compound B: 3.58 g/cm3

Compound C: 3.45 g/cm3

Compound D: 4.58 g/cm3

Conclusion : There is a significant inverse correlation between particle size and combustion shrinkage ratio, and therefore between particle size and specific gravity. Even when the near-optimal (0.5 μm to 20 μm) ferrite particles account for up to 95% of the weight of the pre-fired ceramic body, a fired ceramic body having such particles is also feasible. Further experiments have found that average pre-fired ferrite particles having a diameter greater than 3 microns but less than 600 microns are preferred. In the range of 0.98 μm to 3.8 μm of the average calcined ferrite grain size, the larger the average pre-fired ferrite grain size, the higher the specific gravity of the fired ceramic body. However, as indicated above, this trend does not exist for an average pre-fired ferrite particle size greater than 600 microns. The best fired ceramic body contains the ferrite according to the foregoing embodiments and methods and has a specific gravity of more than 3.8 g/cm 3 and a compressive strength of more than 150 MPa.

Claims (42)

A molded body for a structural building, characterized in that after forming a molding material comprising a ferrite powder in a ratio of 60 wt%, it is fired to have a density of 3.5 g/cm ³ after firing. Enhance the radiation shielding effect. A molded body for a structural building according to claim 1, wherein the molding material mentioned above is press-formed and has a compressive strength of 100 MPa or more. The molded body for a structural building according to claim 1 or 2, wherein the ferrite powder is represented by the following formula: composition formula: AO‧nX ₂ O ₃ (however, it should be noted that in the composition formula, A is one or more types of elements selected from the group consisting of Mg, Ca, Mn, Co, Ni, Cu, Sr, Ba or Pb, and X is one or more types of elements selected from the group consisting of Fe, Co or Ni, And n is defined as a molar ratio of an integer from 1 to 9. A shaped body for a structural building according to claim 3, wherein the A of the composition formula mentioned above is one or more types of elements selected from the group consisting of Sr, Ba or Pb. A shaped body for a structural building according to claim 3 or 4, wherein the X-based Fe in the composition formula mentioned above. The shaped body for a structural building according to any one of claims 1 to 5, wherein the shaped material contains clay as a main component, the clay having one or more types of oxides selected from the group consisting of Al ₂ : O ₃ , SiO ₂ or B ₂ O ₃ . The molded article for a structural building according to any one of claims 1 to 6, wherein the firing temperature is from 1,000 ° C to 1,400 ° C and the firing time is from 5 hours to 150 hours. The shaped body for a structural building according to any one of claims 1 to 7, wherein the ferrite powder has a particle diameter of 5 μm to 8 mm. A brick comprising the shaped body for a structural building according to any one of claims 1 to 8. A manufacturing method for a formed body of a structural building, characterized in that a forming system for a structural building is formed by the manufacturing method by forming a forming material including a ferrite powder in a ratio of 60 wt% into a prescribed shape. It was fired to obtain a density of 3.5 g/cm ³ after firing and the radiation shielding effect was enhanced. A ceramic body comprising a fired clay and a ferrite powder, wherein 60% or more of the weight of the ceramic body is attributed to particles between 0.5 μm and 20 μm before firing, and the density after firing It is at least 3.5 g/cm ³ . The ceramic body of claim 11, wherein the composition of the particles is represented by the following composition formula: AO‧nX ₂ O ₃ , A is one or more types of elements selected from the group consisting of Mg, Ca, Mn, Co, Ni, Cu, Sr, Ba or Pb, X is one or more types of elements selected from the group consisting of Fe, Co or Ni, and n is defined as a molar ratio of integers from 1 to 9. The ceramic body of claim 11, wherein the A of the composition formula mentioned above is one or more types of elements selected from the group consisting of Sr, Ba or Pb. The ceramic body of claim 12 or 13, wherein the X-based Fe in the composition formula mentioned above. The ceramic body according to any one of claims 11 to 14, wherein the clay has one or more types of oxides selected from the group consisting of Al ₂ O ₃ , SiO ₂ or B ₂ O ₃ . The ceramic body according to any one of claims 11 to 15, wherein the firing temperature is from 1,000 ° C to 1,400 ° C and the firing time is between 3 hours and 150 hours. The ceramic body according to any one of claims 11 to 15, wherein 70% or more of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 20 μm. The ceramic body according to any one of claims 11 to 15, wherein 80% or more of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 20 μm. The ceramic body according to any one of claims 11 to 15, wherein 90% or more of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 20 μm. The ceramic body according to any one of claims 11 to 15, wherein 95% or more of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 20 μm. A ceramic body comprising a fired clay and a ferrite powder, wherein 60% or more of the weight of the ceramic body is attributed to particles between 0.5 μm and 600 μm before firing, and the density after firing It is at least 3.5 g/cm ³ . The ceramic body of claim 21, wherein the composition of the particles is represented by the following composition formula: AO‧nX ₂ O ₃ , A is one or more types of elements selected from the group consisting of Mg, Ca, Mn, Co, Ni, Cu, Sr, Ba or Pb, X is one or more types of elements selected from the group consisting of Fe, Co or Ni, and n is defined as a molar ratio of integers from 1 to 9. The ceramic body of claim 22, wherein the A of the composition formula mentioned above is one or more types of elements selected from the group consisting of Sr, Ba or Pb. The ceramic body of claim 22 or 23 or 11, wherein the X-based Fe in the composition formula mentioned above. The ceramic body according to any one of claims 21 to 24, wherein the clay has one or more types of oxides selected from the group consisting of Al ₂ O ₃ , SiO ₂ or B ₂ O ₃ . The ceramic body according to any one of claims 21 to 25, wherein the firing temperature is from 1,000 ° C to 1,400 ° C and the firing time is between 3 hours and 150 hours. The ceramic body according to any one of claims 21 to 25, wherein 70% or more of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 600 μm. The ceramic body according to any one of claims 21 to 25, wherein 80% or more of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 600 μm. The ceramic body according to any one of claims 21 to 25, wherein 90% or more of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 600 μm. The ceramic body according to any one of claims 21 to 25, wherein 95% or more of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 600 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein the weight of the ceramic body of 60% or more before firing is attributed to particles having a size between 0.5 μm and 20 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein the weight of the ceramic body of 60% or more before firing is attributed to particles having a size between 0.5 μm and 600 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein the weight of the ceramic body of 70% or more before firing is attributed to particles having a size between 0.5 μm and 20 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein the weight of the ceramic body of 70% or more before firing is attributed to particles having a size between 0.5 μm and 600 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein the weight of the ceramic body of 80% or more before firing is attributed to particles having a size between 0.5 μm and 20 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein the weight of the ceramic body of 80% or more before firing is attributed to particles having a size between 0.5 μm and 600 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein 90% or more of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 20 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein the weight of the ceramic body of 90% or more before firing is attributed to particles having a size between 0.5 μm and 600 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein the weight of the ceramic body of 95% or more before firing is attributed to particles having a size between 0.5 μm and 20 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein the weight of the ceramic body of 95% or more before firing is attributed to particles having a size between 0.5 μm and 600 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein at least 95% and less than 98% of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 20 μm. A method for producing a ceramic body, characterized in that the ceramic system is obtained by firing in a method in which a clay having a proportion of ferrite powder mixed with at least 60 wt% is formed into a prescribed shape and fired. The post-density is 3.5 g/cm ³ and wherein at least 95% and less than 98% of the weight of the ceramic body before firing is attributed to particles having a size between 0.5 μm and 600 μm.