JPWO2020026766A1 - Manufacturing method of glass bulk body - Google Patents

Abstract

Laser irradiation is performed on an aggregate of sand grains, rock or concrete, and a dense glass layer is continuously formed in an arbitrary region using the silica (SiO2) component contained in the aggregate of sand grains, rock or concrete as a raw material. Provided is a simple method for producing a glass bulk body. Further, the present invention provides a glass bulk body in which the surface of a base material made of an aggregate of sand grains, rock or concrete is vitrified and a glass layer is continuously formed in an arbitrary region. A method for producing a glass bulk body that vitrifies the surface of an aggregate of sand grains, rocks, or concrete. The aggregates of sand grains, rocks, and concrete contain a silica (SiO2) component, and the surface is irradiated with a laser at a fixed point. It has a first step of forming a molten portion and a second step of moving the irradiation position of the laser at a scanning speed at which the melted portion continuously expands to form a glass layer, and the first step and the first step. It is a method for producing a glass bulk body, characterized in that two steps are continuously performed.

Description

The present invention relates to a method for producing a glass bulk body, and more specifically, to a method for producing a glass bulk body capable of vitrifying an arbitrary region on the surface of an aggregate of sand grains, rock or concrete.

Since the laser beam has no mass, laser processing can be performed basically without noise and vibration, and not only processing and welding of metal materials, but also processing of concrete materials has attracted attention, and it has entered the construction field. Investigation into the applicability of is started.

Specifically, it has been reported that when a laser is applied to concrete or rock containing a silica component, the silica component in the irradiated area melts and vitrifies, and this phenomenon is used for rock cutting and concrete. Drilling holes in materials and surface treatment are being studied.

For example, in Patent Document 1 (Japanese Unexamined Patent Publication No. 6-80485), a surface adhering material containing an inorganic substance as a main component is arranged on the surface of a building material base material, and the surface layer is melted by irradiating with a laser. , A surface treatment method for obtaining a building material on which a strong film is formed has been proposed.

In the laser welding apparatus described in Patent Document 1, a strong cured film can be produced because both the building material base material and the surface adhering material are melted, and a colored cured film is formed on the surface of the construction material. It is said that it can be easily formed and that the surface of construction materials can be provided with heat insulating and sound insulating effects.

Further, in Patent Document 2 (Japanese Unexamined Patent Publication No. 11-19785), the hardened cement body is irradiated with a laser to form a fragile layer having a reduced strength of the hardened cement body, and then the fragile layer is removed. A method for drilling a hardened cement body, which is characterized by drilling with a laser, has been proposed.

In the method for drilling a hardened cement body described in Patent Document 2, a fragile layer having sufficiently reduced strength is formed on the hardened cement body as a drilling object by using a device with low noise and low vibration, and then the fragile body is formed. To remove the layer, the fragile layer can be removed using a slow rotating mechanical or manual tool. As a result, it is possible to suppress the generation of vibration and noise at the time of drilling as much as possible, and to improve the working environment and the surrounding environment at the time of drilling.

Japanese Unexamined Patent Publication No. 6-80485 Japanese Unexamined Patent Publication No. 11-19785

However, in the construction material and its surface treatment method described in Patent Document 1, it is essential to use a surface adhering material containing an inorganic substance whose main component is adjusted for laser irradiation, and the laser. The surface adhering material is melted by irradiation and coated on the surface of the building material base material. That is, the surface treatment method described in Patent Document 1 is a method of coating an inorganic substance using laser irradiation, using silica (SiO ₂ ) component contained in an aggregate of sand grains, rock or concrete as a raw material, and any of these. It is completely different from the method for producing a glass bulk body in which a glass layer is formed in the region of.

Further, the method for drilling a hardened cement body described in Patent Document 2 is to form a fragile layer on the hardened cement body by using laser irradiation, and an arbitrary dense glass layer in which the formation of defects and the like is suppressed is arbitrary. It is a technique that has a direction completely opposite to the method of forming a region. Further, the formation of the fragile layer is limited to a narrow region corresponding to the perforated region, and it is not necessary to continuously form the fragile layer. That is, in the known prior art, a silica (SiO ₂ ) component contained in an aggregate of sand grains, rock or concrete is used as a raw material, and a dense glass layer is continuously formed in any of these regions (particularly in a wide region). There is no way to form it.

In view of the above problems in the prior art, an object of the present invention is to irradiate an aggregate of sand grains, rock or concrete with a laser, and to provide silica (SiO _{2) contained in the aggregate of sand grains, rock or concrete.} ) Is used as a raw material to provide a simple method for producing a glass bulk body in which a dense glass layer is continuously formed in an arbitrary region (particularly in a wide region). Another object of the present invention is to provide a glass bulk body in which the surface of a base material made of an aggregate of sand grains, rock or concrete is vitrified and a glass layer is continuously formed in an arbitrary region.

In order to achieve the above object, the present inventor has conducted extensive research on a laser irradiation method capable of forming a dense glass layer continuously and over a wide area. After forming the above, it was found that it is extremely important to continuously expand the molten portion by scanning the laser, and the present invention was reached.

That is, the present invention
A method for producing a glass bulk body that vitrifies the surface of an aggregate of sand grains, rock or concrete.
The aggregate of sand grains, the rock and the concrete contain a silica (SiO ₂ ) component.
The first step of irradiating the surface with a laser at a fixed point to form a fused portion,
It has a second step of moving the irradiation position of the laser at a scanning speed at which the molten portion continuously expands to form a glass layer.
Performing the first step and the second step in succession,
Provided is a method for producing a glass bulk body, which is characterized by the above.

By irradiating the surface of an aggregate of sand grains, rock or concrete containing a silica (SiO ₂ ) component with a fixed point laser, a molten portion that serves as a seed for a glass layer can be formed. After that, the molten portion can be expanded by scanning the laser in an arbitrary direction. Here, if the scanning speed is too high, the molten portion is divided or narrowed, and a dense glass layer cannot be continuously formed. On the other hand, if the scanning speed is too slow, it may _{be dense due to evaporation of the silica (SiO 2} ) component required for forming the glass layer, steam explosion, aggregates of sand grains as the base material, and changes in the shape of rock or concrete. The glass layer cannot be formed continuously.

In the method for producing a glass bulk body of the present invention, it is preferable to dispose a powder containing a _{silica (SiO 2) component on the surface as a pretreatment step of the first step. By supplying the silica (SiO 2} ) component from the powder in addition to the _{silica (SiO 2} ) component contained in the aggregate of sand grains, rock or concrete, the glass layer can be formed more stably and efficiently. can.

Further, in the method for producing a glass bulk body of the present invention, it is preferable to perform the pretreatment step, the first step and the second step on the glass layer to increase the thickness of the glass layer. .. The glass layer can be formed by performing the first step and the second step once, respectively, but by resupplying the silica (SiO ₂ ) component by powder and performing the first step and the second step, the glass is formed. The thickness and area of the layer can be increased. Here, the treatment is not limited to one time, and a glass layer having an arbitrary thickness and area can be formed by repeating the treatment a plurality of times as needed.

Further, in the method for producing a glass bulk body of the present invention, it is preferable to supply the powder to the molten portion in the second step. _{By supplying the powder containing the silica (SiO 2} ) component to the molten portion in the second step, a dense glass layer can be formed more stably and efficiently. The method for supplying the powder is not particularly limited, and the powder may be supplied by various conventionally known methods. For example, a powder supply method used in laser cladding (a nozzle for supplying powder to the vicinity of a molten portion, a nozzle for supplying powder coaxially with laser irradiation, or the like) can be used.

Further, in the method for producing a glass bulk body of the present invention, it is preferable that ^{the power density of the laser on the surface is 3 to 15 W / mm 2 in the first step.} By setting the power density of the laser to 3 W / mm ² or more, the silica (SiO ₂ ) component contained in the base material can be sufficiently melted to form a seed region of the glass layer. Further, by setting the value to 15 W / mm ² or less, it is possible to suppress the inhibition of densification of the glass layer due to steam explosion or the like, and it is also possible to suppress the deformation of the base material.

Further, in the method for producing a glass bulk body of the present invention, it is preferable that ^{the power density of the laser on the surface is 20 to 40 W / mm 2 in the second step.} By setting the power density of the laser to 20 W / mm ² or more, the molten state can be sufficiently maintained even if the irradiation position of the laser is moved, and the molten portion can be continuously expanded. Further, by setting the value to 40 W / mm ² _{or less, evaporation of the silica (SiO 2} ) component, steam explosion, deformation of the base material, and the like can be suppressed.

Further, in the method for producing a glass bulk body of the present invention, it is preferable that the scanning speed is 0.01 to 2.0 m / min in the second step. By setting the scanning speed of the laser to 0.01 m / min or more, _{it is possible to suppress evaporation of silica (SiO 2} ) components, steam explosion, deformation of the base material, and the like. Further, by setting the value to 2.0 m / min or less, the molten state can be sufficiently maintained even if the laser irradiation position is moved, and the molten portion can be continuously expanded.

Further, in the method for producing a glass bulk body of the present invention, it is preferable that the sand aggregate and / or the rock is present at the outer edge of the excavation region when excavating the ground or the seabed. When excavating the ground or the seabed, there is a problem that the outer edge of the excavation area collapses with the excavation. Generally, excavation is carried out using a casing, but when the stratum is standing (such as the stratum of an oil field), it easily collapses and there are cases where the casing cannot be performed. Here, by vitrifying the region that easily collapses, the inner diameter becomes constant, and the casing can be easily installed. In addition, when using a casing, there is a problem that the inner diameter decreases as the excavation depth increases, but if the outer edge of the excavation area (inner diameter of the excavation area) can be vitrified to prevent collapse, it is necessary to use a casing. Is gone.

Further, in the method for producing a glass bulk body of the present invention, it is preferable to incorporate high-level radioactive waste into the molten portion. Currently, high-level radioactive waste is sealed in a stainless steel container together with molten glass to form a vitrified waste, which is buried in an underground facility together with the container, but a large manufacturing facility is required to manufacture the vitrified waste. In addition to the need, a large burial site is needed. On the other hand, by taking high-level radioactive waste into the molten part, it can be made into a vitrified waste very easily, and a large stainless steel container is not required. In addition, the vitrified body can be formed deep in the ground, eliminating the need for a large-scale burial site.

By "in-situ manufacturing and burial" of vitrified waste containing high-level radioactive waste as described above, large-scale manufacturing equipment is not required and it is possible to deal with it with the minimum burial site. Secondary high level radioactive waste can be reduced very effectively.

Further, in the method for producing a glass bulk body of the present invention, it is preferable to arrange the powder in a groove of a concrete member and fill the groove with the glass layer. By filling the groove of the concrete member with a glass layer, the corrosion resistance and aesthetic appearance of the concrete member can be improved. When a groove is present between two or more concrete members, these concrete members can be joined via the glass layer by filling the groove with a glass layer. Further, simple joining can also be achieved by abutting the concrete members with each other and forming a glass layer along the butt line.

In addition, the present invention
An aggregate of sand grains, a base material made of rock or concrete, and
With a glass layer,
The base material portion and the glass layer are continuously integrated with each other via a boundary region having bubbles.
Also provided is a glass bulk body, characterized by.

_{In the glass bulk body of the present invention, a glass layer made of a silica (SiO 2} ) component contained in a base material made of an aggregate of sand grains, rock or concrete is formed, so that the base material and a dense glass layer are formed. Is continuously integrated with. Further, air bubbles are present in the boundary region between the base material portion and the glass layer, and the structure is such that the physical difference between the base material portion and the glass layer is effectively alleviated by the air bubbles.

Further, in the glass bulk body of the present invention, it is preferable that the glass layer has transparency. The glass layer formed in the glass bulk body of the present invention is dense, and the glass layer has transparency, for example, a building member (outer wall, etc.) having an excellent aesthetic appearance utilizing light transmission. ) Can be used. The glass bulk body of the present invention can be suitably obtained by the method for producing the glass bulk body of the present invention.

According to the method for producing a glass bulk body of the present invention, laser irradiation is performed on an aggregate of sand grains, rock or concrete, and the silica (SiO ₂ ) component contained in the aggregate, rock or concrete of these sand grains is used as a raw material. It is possible to provide a simple method for producing a glass bulk body in which a dense glass layer is continuously formed in an arbitrary region (particularly in a wide region).

Further, according to the glass bulk body of the present invention, a glass bulk body in which the surface of a base material made of an aggregate of sand grains, rock or concrete is vitrified and a dense glass layer is continuously formed in an arbitrary region. Can be provided.

It is a schematic cross-sectional view of the glass bulk body of this invention. It is sectional drawing of the sample obtained in Example 1. FIG. It is a photograph which shows the state which light is transmitted through the glass layer formed in Example 1. FIG. It is an appearance photograph of the sample obtained in Example 2. It is an appearance photograph of the sample obtained in Example 3. It is an external photograph of the concrete piece which formed the groove used in Example 4. FIG. It is an enlarged photograph of a groove formed in a concrete piece. It is an external photograph of a groove filled with powder. It is an external photograph which shows the state which vitrified the powder. It is an appearance photograph of the processing area finally obtained in Example 4. It is an appearance photograph of the concrete joint obtained in Example 5.

Hereinafter, the method for producing the glass bulk body of the present invention and typical embodiments of the glass bulk body will be described in detail with reference to the drawings, but the present invention is not limited to these. In the following description, the same or corresponding parts may be designated by the same reference numerals, and duplicate description may be omitted. Moreover, since the drawings are for conceptually explaining the present invention, the dimensions of each component represented and their ratios may differ from the actual ones.

(1) Method for Manufacturing Glass Bulk Body The method for manufacturing a glass bulk body of the present invention is a method for manufacturing a glass bulk body that vitrifies the surface of an aggregate of sand grains, rocks, or concrete, and irradiates a laser at a fixed point. It has one step and a second step of scanning the laser. Hereinafter, each process and the like will be described in detail.

1. 1. First step (fixed point irradiation of laser)
The first step is a step of irradiating the surface of an aggregate of sand grains, rock or concrete with a laser at a fixed point to form a seed (melted portion) which will later become a glass layer.

An aggregate of sand grains, rock or concrete as a base material for forming a glass layer _{contains a silica (SiO 2} ) component, and the silica (SiO ₂ ) component becomes a glass layer. The term "aggregate of sand grains" means an aggregate of sand grains widely, and includes, for example, an aggregate of sand grains hardened by applying pressure, sand grains existing on the ground or the seabed, and the like.

Further, the aggregate of sand grains, rock or concrete is _{not particularly limited as long as it contains a silica (SiO 2} ) component, and various conventionally known aggregates of sand grains, rock or concrete can be used. For example, silica sand, decomposed granite soil, or the like can be used for the sand grains, and granite, sandstone, mudstone, tuff, or the like can be used as the rock. Further, for example, a chimney, which is a structure formed by precipitating and precipitating metals and the like contained in hot water ejected from the seabed, can also be targeted.

Further, the type of laser used for irradiation is not particularly limited as long _{as the silica (SiO 2} ) component contained in the aggregate of sand grains, rock or concrete can be sufficiently melted, and various conventionally known lasers are used. Can be done. Here, examples of the laser that can be preferably used include a semiconductor-excited solid-state laser, and for example, a semiconductor laser can be used.

In the first step, the power density of the laser on the surface of the base material is preferably 3 to ^{15 W / mm 2.} By setting the power density of the laser to 3 W / mm ² or more, the silica (SiO ₂ ) component contained in the base material can be sufficiently melted to form a seed region of the glass layer. Further, by setting the value to 15 W / mm ² or less, it is possible to suppress the inhibition of densification of the glass layer due to steam explosion or the like, and it is also possible to suppress the deformation of the base material. The power density of the laser is more preferably ^{5 to 10 W / mm 2.}

Further, as a pretreatment step of the first step, it is preferable to dispose a powder containing a _{silica (SiO 2) component on the surface of the base material. By supplying the silica (SiO 2} ) component from the powder in addition to the _{silica (SiO 2} ) component contained in the base material, the glass layer can be formed more stably and efficiently. The powder is _{not particularly limited as long as it contains a silica (SiO 2} ) component, but for example, glass powder, silica particles, silica sand, decomposed granite soil, etc. can be used, and these are mixed and used. May be good.

When the powder is arranged on the surface of the base material as the pretreatment step of the first step, the method of the arrangement is not particularly limited. It is preferable to level with or the like.

2. Second step (laser scanning)
The second step is a step for continuously scanning the laser from the fixed point irradiation of the laser in the first step to expand the molten portion (seed region of the glass layer).

In the second step, the power density of the laser on the surface of the base material is preferably ^{20 to 40 W / mm 2.} By setting the power density of the laser to 20 W / mm ² or more, the molten state can be sufficiently maintained even if the irradiation position of the laser is moved, and the molten portion can be continuously expanded. Further, by setting the value to 40 W / mm ² _{or less, evaporation of the silica (SiO 2} ) component, steam explosion, deformation of the base material, and the like can be suppressed. The more preferable power density of the laser is 25 to 35 W / mm ² .

The scanning speed of the laser is preferably 0.01 to 2.0 m / min. By setting the scanning speed of the laser to 0.01 m / min or more, _{it is possible to suppress evaporation of silica (SiO 2} ) components, steam explosion, deformation of the base material, and the like. Further, by setting the value to 2.0 m / min or less, the molten state can be sufficiently maintained even if the laser irradiation position is moved, and the molten portion can be continuously expanded. The more preferable scanning speed of the laser is 0.1 to 1.0 m / min.

In the second step, it is preferable to supply the powder containing _{the silica (SiO 2) component described above to the molten portion. By supplying the powder containing the silica (SiO 2} ) component to the molten portion in the second step, a dense glass layer can be formed more stably and efficiently. The method for supplying the powder is not particularly limited, and the powder may be supplied by various conventionally known methods. For example, a powder supply method used in laser cladding (a nozzle for supplying powder to the vicinity of a molten portion, a nozzle for supplying powder coaxially with laser irradiation, or the like) can be used.

The thickness of the glass layer can be increased by subjecting the glass layer obtained in the second step to the pretreatment step, the first step and the second step. The glass layer can be formed by performing the first step and the second step once, respectively, but by resupplying the silica (SiO ₂ ) component by powder and performing the first step and the second step, the glass is formed. The thickness and area of the layer can be increased. Here, the treatment is not limited to one time, and a glass layer having an arbitrary thickness and area can be formed by repeating the treatment a plurality of times as needed.

The atmosphere of the laser irradiation region is not particularly limited in both the first step and the second step, and can be performed, for example, in the atmosphere or in an inert gas atmosphere.

3. 3. Application example of the method for producing a glass bulk body The method for producing a glass bulk body of the present invention can not only form a dense glass layer in an arbitrary region on the surface of an aggregate of sand grains, rock or concrete, but also various methods. There are effective applications of.

3-1. Prevention of collapse of excavation area When excavating the ground or the seabed, the problem is that the outer edge of the excavation area collapses with the excavation. On the other hand, by vitrifying the outer edge of the excavation area (inner diameter of the excavation area), the collapse can be suppressed extremely effectively.

For example, strata are standing in the strata of oil fields, and collapse caused by fragile strata becomes a serious problem. When the collapse occurs, casing cannot be performed, but the collapse can be suppressed by forming a glass layer on the inner wall of the excavation area. In addition, the casing can be installed by stabilizing the diameter and shape of the inner wall.

In addition, when using a casing, there is a problem that the inner diameter decreases as the excavation depth increases, but if the outer edge of the excavation area (inner diameter of the excavation area) can be vitrified to prevent collapse, it is necessary to use a casing. Is gone.

3-2. Treatment of high-level radioactive waste Currently, high-level radioactive waste is sealed in a stainless steel container together with molten glass to form a vitrified waste, which is buried in an underground facility together with the container. In addition to requiring large-scale manufacturing equipment, a large-scale burial site is required. On the other hand, by taking high-level radioactive waste into the molten part, it can be made into a vitrified waste very easily, and a large stainless steel container is not required. In addition, the vitrified body can be formed deep in the ground, eliminating the need for a large-scale burial site.

By "in-situ manufacturing and burial" of vitrified waste containing high-level radioactive waste, large-scale manufacturing equipment is not required and it is possible to deal with it with a minimum of burial site. As a result, it is secondary. High level radioactive waste can be reduced very effectively.

Here, the timing of incorporating high-level radioactive waste into the glass layer is not particularly limited, but for example, when the powder is placed on the surface of the base material as a preliminary treatment in the first step, it is between the powder and the base material. By arranging the high-level radioactive waste and then performing the first step and the second step, the high-level radioactive waste can be taken into the glass layer. In addition, when the powder is supplied to the molten portion in the second step, a high level radioactive substance may be supplied at the same time.

3-3. Repair and Reinforcement and Joining of Concrete Members The concrete members can be repaired and / or reinforced by arranging powder containing a _{silica (SiO 2) component in the grooves of the concrete member and filling the grooves with a glass layer.} Here, the groove may be intentionally formed, or a naturally generated crack or the like may be used as the groove. The formation of the glass layer not only improves the mechanical properties and corrosion resistance, but also improves the aesthetic appearance.

Further, when a groove is present between two or more concrete members, these concrete members can be joined via the glass layer by forming a glass layer in the groove. Further, simple joining can be achieved by abutting the concrete members and forming a glass layer along the butt line.

(2) Glass bulk body FIG. 1 shows a schematic cross-sectional view of the glass bulk body of the present invention. The glass bulk body 2 has a base material portion 4 made of an aggregate of sand grains, rock or concrete, and a glass layer 6, and the base material portion 4 and the glass layer 6 are interposed via a boundary region having bubbles 8. It is continuously integrated.

The base material portion 4 is composed of an aggregate of sand grains, rock or concrete, and these contain a silica (SiO ₂ ) component. The aggregate, rock or concrete _{of sand grains is not particularly limited as long as it contains a silica (SiO 2} ) component, and is an aggregate, rock or concrete of various conventionally known sand grains. For example, sand grains are silica sand, decomposed granite soil, etc., and rocks are granite, sandstone, mudstone, tuff, etc. In addition, concrete contains silica sand and clay, and these components have silica (SiO ₂ ).

The air bubbles 8 formed in the boundary region between the dense glass layer 6 and the base material portion 4 alleviate the difference in density and physical properties between the glass layer 6 and the base material portion 4, and the difference in density and physical properties between the glass layer 6 and the base material portion 4 are alleviated. It is continuously integrated with 4. Here, the size of the bubble 8 is preferably 50 to 2000 μm, more preferably 100 to 1500 μm. When the size of the bubbles 8 is 50 μm or more, the difference between the glass layer 6 and the base material portion 4 can be alleviated, and when the size is 2000 μm or less, embrittlement of the boundary region can be suppressed.

The glass layer 6 preferably has transparency. Since the glass layer 6 has transparency, it can be used, for example, as a building member (outer wall or the like) having an excellent aesthetic appearance utilizing the transmission of light. The glass bulk body of the present invention can be suitably obtained by the method for producing the glass bulk body of the present invention.

Although the typical embodiments of the present invention have been described above, the present invention is not limited to these, and various design changes are possible, and all of these design changes are included in the technical scope of the present invention. Is done.

<< Example 1 >>
A semiconductor laser manufactured by Laserline Co., Ltd. was used to irradiate the surface of sandstone with a laser. Specifically, the laser output was 800 W, the laser beam diameter on the surface of the sandstone was 2 × 39 mm, and fixed point irradiation was performed for 60 seconds (first step). The laser power density in the first step is 10 W / mm ² .

Since it was confirmed that a sufficient melting region was formed by the fixed point irradiation in the first step, the laser output was increased to 2800 W and the moving speed was set to 48 mm / min to move the laser irradiation position (second step). The laser power density in the second step is 35 W / mm ² . By setting an appropriate laser power density and moving speed, the molten portion was continuously expanded without interruption by scanning the laser. A cross-sectional photograph of the treated sandstone is shown in FIG.

From FIG. 2, it can be seen that a dense glass layer is formed over a wide area on the surface region of the sandstone. Further, the glass layer is continuously formed from sandstone which is a base material, and bubbles are formed at the boundary between the glass layer and the base material. The cracks in the sandstone were mainly generated during the preparation of the cross-sectional sample.

FIG. 3 shows a state in which the obtained glass layer is separated and irradiated with light from the back surface. The light emitted from the back surface passes through the glass layer, and it can be confirmed that the formed glass layer has transparency.

<< Example 2 >>
A semiconductor laser manufactured by Laserline Co., Ltd. was used to irradiate the surface of the tuff with a laser. Specifically, the laser output was 800 W, the laser beam diameter on the surface of the tuff was 2 × 39 mm, and fixed point irradiation was performed for 60 seconds (first step). The laser power density in the first step is 10 W / mm ² .

Since it was confirmed that a sufficient melting region was formed by the fixed point irradiation in the first step, the laser output was increased to 2800 W and the moving speed was set to 48 mm / min to move the laser irradiation position (second step). The laser power density in the second step is 35 W / mm ² . By setting an appropriate laser power density and moving speed, the molten portion was continuously expanded without interruption by scanning the laser.

In the second step, a powder containing tuff components was supplied to the molten part. By supplying the powder containing the tuff component to the molten portion in the second step, a dense glass layer can be formed more stably and efficiently. A photograph of the appearance of the treated tuff is shown in FIG.

From FIG. 4, it can be seen that a dense glass bulk body having transparency is formed over a wide area in the surface region of the tuff. Further, the glass bulk body is continuously formed from the tuff which is the base material, and no defects such as cracks are observed at the boundary between the glass bulk body and the base material.

<< Example 3 >>
A semiconductor laser manufactured by Laserline Co., Ltd. was used to irradiate the concrete surface with a laser. Specifically, the laser output was 2800 W, the laser beam diameter on the concrete surface was 2 × 39 mm, and fixed point irradiation was performed for 1 second (first step). The laser power density in the first step is 35 W / mm ² .

Since it was confirmed that a sufficient melting region was formed by the fixed point irradiation in the first step, the laser irradiation position was moved with the moving speed set to 48 mm / min (second step). In this embodiment, the laser output of the second step is not increased from the first step.

A photograph of the appearance of the obtained sample is shown in FIG. In Example 3, it can be seen that the black glass layer is formed over a wide area.

<< Example 4 >>
Using a semiconductor laser manufactured by Laserline Co., Ltd., an attempt was made to fill a groove (depth 20 mm, length 100 mm) formed on the surface of concrete with a glass layer. A photograph of the appearance of the concrete piece having a groove is shown in FIG. An enlarged photograph of the groove is shown in FIG. Here, in the first layer, the bottom of the groove is directly irradiated with a laser to form a glass layer, and in the second to fifth layers, the groove is filled with sandy powder obtained by crushing silica sand, and the laser is applied to the region. Was irradiated to form a glass layer in sequence.

To form the first layer, the laser output was 540 W, the laser beam diameter at the bottom surface of the groove was 2 × 27 mm, and fixed point irradiation was performed for 1 second (first step). The laser power density in the first step is 10 W / mm ² . Then, the laser output was set to 1900 W, and the laser was scanned at a speed of 48 mm / min. The laser power density in the second step is 35 W / mm ² .

For the formation of the second to fifth layers, sandy powder obtained by crushing silica sand was supplied to the molten portion, the laser output was 1900 W, and the laser was scanned at a speed of 48 mm / min. The laser power density in this step is 35 W / mm ² .

FIG. 8 and FIG. 9 show an external photograph of the groove in a state of being filled with powder and an external photograph of the region after vitrification. It can be seen that the filled powder (silica sand powder) is made into dense glass by laser irradiation.

An enlarged photograph of the groove of the finally obtained sample is shown in FIG. It can be seen that the grooves are completely filled with a dense glass layer, and that even a deep groove can be filled to the surface by the multi-layered glass layer.

<< Example 5 >>
An attempt was made to join concrete pieces to each other using a semiconductor laser manufactured by Laserline. The concrete pieces were brought into contact with each other at the end faces, and the concrete pieces were joined by vitrification of the outer peripheral region of the end faces. Here, a powder having a height of about 3 mm to 5 mm was supplied to the laser irradiation surface, and a sandy powder obtained by crushing sandstone was used as the powder.

Specifically, the laser output was 1900 W, the laser beam diameter on the concrete surface was 2 × 27 mm, and fixed point irradiation was performed for 1 second (first step). The laser power density in the first step is 35 W / mm ² . Then, the laser irradiation position was moved at a speed of 48 mm / min along the outer peripheral region of the end face (second step). In this embodiment, the laser output of the second step is not increased from the first step.

FIG. 11 shows a photograph of the appearance of the sample after irradiating the outer peripheral region of the end face with a laser for two rounds. It can be confirmed that the outer peripheral region of the butt end face is vitrified and the two concrete pieces are joined.

2 ... Glass bulk body,
4 ... Base material part,
6 ... Glass layer,
8 ... Bubbles.

Claims (12)

A method for producing a glass bulk body that vitrifies the surface of an aggregate of sand grains, rock or concrete.
The aggregate of sand grains, the rock and the concrete contain a silica (SiO ₂ ) component.
The first step of irradiating the surface with a laser at a fixed point to form a fused portion,
It has a second step of moving the irradiation position of the laser at a scanning speed at which the molten portion continuously expands to form a glass layer.
Performing the first step and the second step in succession,
A method for producing a glass bulk body. As a pretreatment step of the first step, arranging a powder containing a _{silica (SiO 2) component on the surface,}
The method for producing a glass bulk body according to claim 1. To increase the thickness of the glass layer by subjecting the glass layer to the pretreatment step, the first step and the second step.
The method for producing a glass bulk body according to claim 2. In the second step, supplying the powder to the molten portion,
The method for producing a glass bulk body according to claim 2 or 3. In the first step, the power density of the laser on the surface is set to 3 to 15 W / mm ² .
The method for producing a glass bulk body according to any one of claims 1 to 4. In the second step, the power density of the laser on the surface is set to 20 to 40 W / mm ² .
The method for producing a glass bulk body according to any one of claims 1 to 5. In the second step, the scanning speed is set to 0.01 to 2.0 m / min.
The method for producing a glass bulk body according to any one of claims 1 to 6. The presence of the sand aggregate and / or the rock at the outer edge of the excavation area when excavating the ground or seabed.
The method for producing a glass bulk body according to any one of claims 1 to 7. Incorporating high-level radioactive waste into the melt,
The method for producing a glass bulk body according to any one of claims 1 to 8. The powder is placed in the groove of the concrete member,
Filling the groove with the glass layer,
The method for producing a glass bulk body according to any one of claims 2 to 7. An aggregate of sand grains, a base material made of rock or concrete, and
With a glass layer,
The base material portion and the glass layer are continuously integrated with each other via a boundary region having bubbles.
A glass bulk body characterized by. The glass layer has transparency,
The glass bulk body according to claim 11.

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