JPWO2012043484A1 - Method of melting glass raw material, method of manufacturing molten glass, method of manufacturing glass product, and in-air melting apparatus and glass beads - Google Patents

Abstract

It is an object of the present invention to provide a glass having a high bubble quality with few bubbles. The present invention uses glass raw material particles obtained by granulating a glass raw material composed of a plurality of components, and when the glass raw material is melted by sending the glass raw material particles into a heated gas phase atmosphere, the glass raw material particles are converted into helium. The present invention relates to a method for melting a glass material to be sent into the heated gas phase atmosphere together with at least one of gas and neon gas.

Description

  The present invention relates to a glass raw material melting method, a molten glass manufacturing method, a glass product manufacturing method, a glass bead manufacturing method, an air melting apparatus, and a glass bead.

At present, most glass on a mass production scale, including plate glass, bottle glass, and fiberglass, is used for melting glass materials in a melting furnace. Produced based on the Siemens kiln developed by Siemens. However, since a glass melting furnace requires a large amount of energy, it is desired to reduce the energy consumption of the glass melting furnace from the aspect of industrial energy consumption structural reform. Recently, however, the demand for high-quality, high-value-added glass as a glass plate for display devices has been increasing, and energy consumption has been increasing, so the development of energy-saving technology for glass production is important and urgent. It is considered as an issue.
Against this background, glass production techniques using oxyfuel flames or thermal plasma arcs have been studied as examples of energy-saving glass production techniques.
For example, in Patent Documents 1 and 2, as a glass melting furnace that melts and accumulates glass raw material particles in a high-temperature gas-phase atmosphere to produce molten glass, A glass melting furnace provided with a heating means for forming a high-temperature gas phase atmosphere for melting glass raw material particles is disclosed.

The glass melting furnace described above is an apparatus for forming molten glass by melting glass raw material particles in a high-temperature gas phase atmosphere to form molten glass particles, and accumulating the molten glass particles at the bottom of the glass melting furnace. A manufacturing method in which the glass raw material particles are melted in a high-temperature gas phase atmosphere is known as an air melting method of glass. According to this in-air melting method, it is said that the energy consumption of the glass melting step can be reduced to about 1/3 compared to the conventional Siemens kiln melting method, which enables melting in a short time, It is attracting attention as a technology that can reduce the size of the melting furnace, omit the heat storage chamber, improve the quality, reduce CO ₂ , and shorten the time for changing the glass type.

  The glass raw material particles are made of an aggregate of a mixture of glass raw materials, and those having a particle diameter of 1 mm or less are disclosed. The glass raw material particles put into the glass melting furnace are melted while descending (or flying) in a high-temperature gas phase atmosphere, and each particle becomes molten glass particles, and the molten glass particles fall downward. Accumulate at the bottom of the glass melting furnace to form molten glass. The molten glass particles generated from the glass raw material particles are also expressed as glass droplets. In order to generate molten glass particles from glass raw material particles in a high-temperature gas phase atmosphere in a short time, the particle size of the glass raw material particles needs to be reduced as described above.

In addition, the decomposition gas component generated when the glass raw material particles become molten glass particles, since both the glass raw material particles and the molten glass particles are small in size, most of them are not confined inside the generated molten glass particles. Is released outside the molten glass particles. For this reason, compared with the molten glass obtained by a Siemens kiln, there is little possibility that a bubble will arise in the molten glass obtained by an in-air melting method.
Furthermore, it is preferable that each glass raw material particle is a particle with substantially uniform constituent raw material components, and the glass composition of each molten glass particle resulting therefrom is also uniform. Since the difference in the glass composition between the molten glass particles is small, there is little possibility that a portion having a different glass composition is generated in the molten glass formed by depositing a large number of molten glass particles.

  For this reason, the homogenization means for homogenizing the glass composition of the molten glass required for the conventional glass melting furnace is hardly required in the air melting method. Even if a small number of molten glass particles may have a glass composition different from that of most other molten glass particles, the heterogeneous region of the glass composition in the molten glass is small, and this heterogeneous region is easily homogenized in a short time. Disappear. Thus, in the air melting method, it is said that the heat energy required for homogenization of molten glass can be reduced and the time required for homogenization can be shortened.

Japanese Unexamined Patent Publication No. 2007-297239 Japanese Unexamined Patent Publication No. 2008-290921

  The glass produced by the above-described air melting method has an advantage that bubbles contained in the molten glass can be reduced as compared with the batch-type melting method using a conventional Siemens kiln. The batch-type melting method referred to here is a method in which a mixture of glass raw materials is added onto the previously melted glass melt surface to form a lump (also called a batch pile or batch pile). Is heated by a burner or the like, melting proceeds from the surface of the lump, and gradually becomes a glass melt. In the conventional batch-type melting method, it is essential to add fining agents such as sulfates, halides, Sb, and As compounds, and to remove bubbles, but according to the in-air melting method, Since it is possible to obtain a glass product with less foam (in this specification, a glass product with less foam is also referred to as a glass product with high foam quality), it is possible to obtain a glass product with high foam quality without adding a clarifier. Is considered possible.

  However, in the production of high value-added glass that has been required in recent years, for example, glass products with higher foam quality, a higher clarification effect is also desired for glass after being melted in the air. Even if clarifiers such as nitrates, halides, Sb, and As oxides conventionally used are mixed with glass raw materials used in the air melting method, most of these clarifiers together with the glass raw materials in the gas phase atmosphere. There is a risk of volatilization, and it is considered that it may be difficult to fully exhibit the clarification effect after melting. In addition, Sb and As oxides are relatively difficult to volatilize but are toxic, and their use should be avoided from the environmental viewpoint. Therefore, even if it is a glass obtained by an in-flight melting method, the advent of a technique capable of producing a glass with higher bubble quality is desired.

  Moreover, in the glass substrate for liquid crystal display devices, the glass substrate excellent in high temperature heat processing tolerance than before is required. For example, the switching element for driving the liquid crystal is changed from an amorphous silicon (a-Si) type TFT (thin film transistor) to a polysilicon type TFT, and introduction of a switching element at a higher speed than these is also being studied. However, since a high-speed switching element tends to have a higher heat treatment temperature during element formation, the glass substrate for liquid crystal display devices can withstand higher temperature heat treatment, for example, exceeds 700 ° C. in the process of forming a transistor circuit. There is a demand for a glass having a high strain point, which is not easily deformed or strained even when heat-treated at a high temperature.

  From such a background, the present inventors have been researching and developing a glass substrate having a composition that can withstand a high heat treatment temperature for a display device or the like. However, if the composition is examined in order to improve the heat resistance of the glass substrate, the glass raw material may become hardly soluble although the heat resistance is improved. In addition, depending on the composition of the glass, bubbles are more likely to be generated when melted than the current glass, and bubbles may not easily escape. Therefore, it is hoped that a technology that can produce glass with higher foam quality can be melted without hindrance even if it is less soluble than conventional glass or glass that tends to form bubbles and is difficult to remove bubbles. It is rare.

From the background as described above, the present invention provides a technique for obtaining a glass having a small amount of bubbles and a high bubble quality when the glass raw material particles are melted into molten glass particles by an air melting method capable of energy-saving operation. With the goal. Another object of the present invention is to provide a technique for realizing a glass product having a low foam and high foam quality and exhibiting a strain point exceeding 700 ° C.
Furthermore, the present invention is not limited to the air melting method, and provides a technique for obtaining a glass having a small amount of bubbles and a high bubble quality with respect to a melting method in which glass raw material particles are melted in a high-temperature gas phase atmosphere. And

The glass raw material melting method according to the present invention uses glass raw material particles obtained by granulating a glass raw material comprising a plurality of components, and when the glass raw material particles are heated and melted by sending them into a heated gas phase atmosphere, Glass raw material particles are sent into the heated gas phase atmosphere together with at least one of helium gas and neon gas.
In the present invention, the glass raw material particles can be melted into molten glass particles in the heated gas phase atmosphere.
In the present invention, at least one of an oxyfuel flame and a thermal plasma arc can be used as the heating gas phase atmosphere.

In the present invention, the glass composition after melting by mass percentage based on _{oxides, SiO 2: 61.5~66.0%, Al} 2 O 3: 19~24%, B 2 O 3: 0~1. 2%, MgO: 3 to 8%, CaO: 0 to 7%, SrO: 0 to 9%, BaO: 0 to less than 1%, MgO + CaO + SrO + BaO: 10 to 19%, substantially containing an alkali metal oxide It can be set as the composition which does not. This composition is preferable as a composition in the case of melting an infusible glass in the air.

In the present invention, the glass raw material particles can be sent to a heated gas phase atmosphere together with at least one of the helium gas and neon gas and a fuel gas for forming an oxyfuel flame.
In the present invention, the glass raw material particles and the glass cullet fine powder can be mixed and sent to a heated gas phase atmosphere.

A method for producing a molten glass according to the present invention is a method for producing a molten glass by using the glass raw material melting method described in any one of the above to make the glass raw material particles into molten glass particles in a heated gas phase atmosphere. It is characterized by storing.
The glass bead manufacturing method according to the present invention is a method for producing glass beads by cooling the glass raw material particles into molten glass particles in a heated gas phase atmosphere using the glass raw material melting method described above. It is characterized by.
The method for producing a glass product according to the present invention includes a glass melting step in which the glass raw material particles are heated to form molten glass using the glass raw material melting method described in any one of the above, and a step of forming the molten glass And a step of gradually cooling the glass after molding.
In the present invention, the glass melting step using the glass raw material particles as molten glass includes a step of melting the glass raw material particles in a gas phase atmosphere to obtain molten glass particles, and a glass obtained by accumulating the molten glass particles. And a step of forming a melt.

An air melting apparatus according to the present invention is an air melting apparatus that heats and melts glass raw material particles formed by granulating a glass raw material composed of a plurality of components into molten glass particles, and heats the glass raw material particles. A raw material heating part for forming a heated gas phase atmosphere to melt, a raw material supply part for supplying the glass raw material particles to the heated gas phase atmosphere, glass raw material particles supplied to the raw material heating part, and the molten glass particles And a supply unit for supplying at least one of helium gas and neon gas.
In the air melting apparatus of the present invention, the raw material heating part that forms the heated gas phase atmosphere can be at least one of a granulated melt burner and a thermal plasma arc generator.
In the in-flight melting apparatus of the present invention, a configuration in which a storage unit for molten glass particles is provided so as to communicate with the raw material heating unit may be employed.
In the air melting apparatus of the present invention, a cooling part and a glass bead storage part may be provided so as to communicate with the raw material heating part.

The glass bead according to the present invention uses glass raw material particles formed by granulating a glass raw material composed of a plurality of components, and sends the glass raw material particles together with at least one of helium gas and neon gas in a heated gas phase atmosphere. Glass beads obtained by melting the glass raw material particles in the heated gas phase atmosphere to form molten glass particles, and taking out from the heated gas phase atmosphere as glass beads after melting, including at least one of helium and neon It is characterized by.
In the glass beads according to the present invention, the helium and / or neon is confirmed from the peak count in the temperature programmed desorption analysis.

According to the present invention, the glass raw material particles are melted in a high-temperature gas phase atmosphere while at least one of helium gas and neon gas is present around the glass raw material particles and the molten glass particles in which the glass raw material particles are melted. Not only the method but also a molten glass having a low bubble quality and high foam quality can be obtained.
According to the present invention, since the glass raw material particles are melted by the air melting method in the presence of at least one of helium gas and neon gas around the glass raw material particles and the molten glass particles in which the glass raw material particles are melted, batch processing is performed using a Siemens kiln. By using an in-air melting method capable of energy-saving operation far more than the manufacturing method for obtaining molten glass by a formula, a molten glass having a higher bubble quality with less bubbles can be obtained. Specifically, if glass raw material particles are melted in the air in the presence of at least one of helium gas and neon gas, helium and / or neon are more efficiently taken into the molten glass particles, and the clarification effect causes bubbles to be generated. It is possible to obtain a molten glass having a low bubble quality and a low foam quality.
By applying a thermal plasma arc and / or an oxyfuel flame as the heated gas phase atmosphere, the glass raw material particles can be efficiently and reliably melted into molten glass particles.
By melting glass raw material particles in a heated gas phase atmosphere to form molten glass particles, and then cooling, glass beads having high foam quality with few bubbles can be obtained.

According to the air melting apparatus of the present invention, since the glass raw material particles can be melted by the air melting method while at least one of helium gas and neon gas is present around the glass raw material particles and the molten glass particles, the Siemens kiln is used. Thus, energy-saving operation can be performed far more than the manufacturing method for obtaining molten glass from glass raw material, and a molten glass having high bubble quality with few bubbles can be obtained.
According to the glass bead manufacturing method of the present invention, since it is obtained by an air melting method in which at least one of helium gas and neon gas is present around the glass raw material particles, helium and / or neon is contained therein. Further, glass beads having high foam quality with few bubbles can be obtained due to the clarification effect of neon.
According to the method for producing a glass product of the present invention, a glass product having high foam quality with few bubbles can be obtained by the method for melting a glass raw material and the method for producing a molten glass of the present invention.

FIG. 1 is an explanatory view showing an example of a state in which molten glass is manufactured by carrying out the in-air melting method of a glass raw material according to the present invention. FIG. 2 is a schematic cross-sectional view showing a configuration example of an air melting apparatus for carrying out the same air melting method. FIG. 3 is a cross-sectional view showing an example of a granule melting burner applied to the in-air melting apparatus. FIG. 4 is a cross-sectional view showing another example of a granulated material melting burner applied to the in-air melting device. FIG. 5 is a flowchart showing an example of a glass product manufacturing method according to the present invention. FIG. 6 is a configuration diagram showing an example of a glass bead manufacturing apparatus and a state in which glass beads are manufactured by carrying out the glass raw material melting method according to the present invention. FIG. 7: is a block diagram which shows the other example of the state which implements the melting method of the glass raw material which concerns on this invention, and the state which manufactures molten glass, and the same molten glass. FIG. 8 shows the number of glass bubbles obtained by an example of the glass raw material melting method of the present invention. FIG. 8 (A) shows a microscope of alkali-free glass (A) when melted in the air while being conveyed by air. 8B is a micrograph of the alkali-free glass (A) when it is melted in air while transporting helium, and FIG. 8C is a case when it is melted in air while transporting air. Micrograph and test result of alkali-free glass (B), FIG. 8D shows a microscope photo and test result of alkali-free glass (B) when melted in the air while carrying helium. FIG. 9 shows a temperature desorption gas profile of a glass sample of non-alkali glass (B) obtained when melted in the air. FIG. 10 shows a temperature desorption gas profile of a glass sample of alkali-free glass (B) obtained by normal melting in a helium gas atmosphere.

Hereinafter, preferred embodiments of a glass raw material melting method, a molten glass manufacturing method, a glass bead manufacturing method, a glass product manufacturing, and an air melting apparatus according to the present invention will be described with reference to the accompanying drawings. In addition, the melting method of the glass raw material particles of the present invention is not limited to each embodiment of the air melting method described below, and the same applies when the glass raw material particles are melted in a high-temperature gas phase atmosphere. It is within the scope of the present invention as long as the above effect can be obtained.
In the present invention, glass raw material particles described later are heated in a high-temperature heated gas phase atmosphere to form molten glass particles, and then molten glass is produced. The heating gas phase atmosphere for heating the glass raw material particles is not particularly limited as long as the glass raw material particles can be melted, and various heating means can be used. At least one of a thermal plasma arc such as a direct current type plasma, a multiphase plasma, a high frequency induction plasma, and an oxyfuel flame such as an oxyhydrogen flame or a natural gas-oxygen flame can be used. Among these, because of high efficiency, easy to obtain a large output, relatively low equipment cost, heating under atmospheric pressure, technically established, stable use for a long time In particular, it is preferable to use at least one heating means of an oxyhydrogen flame or an oxyfuel flame of a natural gas-oxygen flame and a thermal plasma arc.

FIG. 1 and FIG. 2 are explanatory views showing an example of a state in which molten glass is manufactured using an air melting apparatus using an oxyfuel flame or a thermal plasma arc in the glass raw material melting method according to the present invention. .
As an example of an air melting apparatus for carrying out the air melting method described below with reference to FIG. 1, an air melting apparatus 1 according to the present embodiment ejects glass raw material particles 2 and generates an oxyfuel flame 3a. A granule melting burner (raw material heating unit) 3 for melting glass raw material particles, which is disposed downward to form, and a front end side in the injection direction of the granule melting burner 3 (the lower side in FIGS. 1 and 2) ) And a storage portion 6 for the molten glass G, and a plurality of arc electrodes 7 installed so as to surround the heated gas-phase atmosphere forming region 5. ing.

  The in-flight melting apparatus 1 shown in FIG. 1 actually has a hollow box type furnace body 8 as shown in FIG. 2, and the granulated body melting burner 3 penetrates the ceiling 8A of the furnace body 8. The glass raw material particles 2 to be described later can be supplied from the raw material supply unit 9 through the supply pipe 10 to the granulated body melting burner 3. The in-flight melting apparatus 1 sends at least one of helium gas and neon gas from a gas supply source (supply unit) 11 connected to the material supply unit 9 to the material supply unit 9 and uses these gases as oxygen as a carrier gas. Or it is comprised so that the glass raw material particle | grains 2 can be supplied to the granule fusion | melting burner 3 with air. In FIG. 1, the main part of the air melting apparatus 1 and the glass raw material particles 2 are mainly shown in order to explain the air melting method.

A heated gas-phase atmosphere forming region 5 is formed in the furnace body 8 below the granule melting burner 3, and a side wall of the furnace body 8 surrounding the heated gas-phase atmosphere forming region 5 is inclined obliquely downward. A plurality of penetrating arc electrodes 7 (four in the example of FIG. 1) are arranged, and the tip of each arc electrode 7 is arranged so as to surround the periphery of the heated vapor phase atmosphere forming region 5. Further, the granulated body melting burner 3 can generate a heated gas phase atmosphere 4 by generating an oxyfuel flame 3a as described later. Further, the discharge of the arc electrode 7 can generate a heated gas phase atmosphere 4 by a thermal plasma arc at the center of the furnace body 8. The heated gas phase atmosphere 4 used here may be formed by using either or both of the oxyfuel flame 3a by the granulated melt burner 3 and the thermal plasma arc by the discharge of the arc electrode 7.
The bottom side of the furnace body 8 is a storage part 6 for molten glass G, and the molten glass G can be discharged from the furnace body 8 through the discharge port 12 formed on the side wall bottom side of the furnace body 8. It is configured as follows. As an example, a molding device 14 or the like is connected to the downstream side in the direction in which the molten glass G is discharged from the furnace body 8, and the formed molten glass G is molded into a desired shape by the molding device 14. It is configured so that it can be obtained. Depending on the foam quality, a vacuum degassing device may be provided before the molding device 14.

In this embodiment, the granulated melt burner 3 provided in the furnace body 8 is configured to be supplied with a fuel gas and a combustion gas, generate an oxyfuel flame 3a, and eject glass raw material particles 2 with a carrier gas. However, the specific structure is not particularly limited, but an example of the specific structure is shown in FIG.
The granulated material melting burner 3 of the embodiment shown in FIG. 3 includes a cylindrical nozzle body 22 having a supply path 21 through which the glass raw material particles 2 pass, and a coating disposed so as to surround the nozzle body 22. A triple structure including a tube 23 and an outer tube 24 arranged so as to surround the periphery of the cladding tube 23 is adopted. A flow path between the nozzle body 22 and the cladding tube 23 is a fuel gas supply path 25, and a flow path between the cladding pipe 23 and the outer pipe 24 is a combustion gas supply path 26. In FIG. 3, a granule dispersion plate 27 is provided on the outlet side of the nozzle body 22.
In the granulated melt burner 3 of the present embodiment, fuel gas such as propane, butane, methane, LPG is introduced into the fuel gas supply path 25 as shown by an arrow 28 in FIG. 3, and combustion gas such as O ₂ gas is introduced. It is introduced into the combustion gas supply path 26 as indicated by an arrow 29 in FIG. The glass raw material particles 2 described above are transported together with a carrier gas comprising at least one of helium gas and neon gas, or a carrier gas containing such gas and oxygen or air, and supplied to the nozzle body 22. And the glass raw material particle | grains 2 can be blown out with the oxyfuel flame 3a injected from the front-end | tip of the granulated body fusion burner 3. FIG. The temperature of the central portion of the heated gas phase atmosphere 4 used in the present embodiment is about 2000 to 3000 ° C. when the combustion flame 3a is, for example, a hydrogen-oxygen combustion flame, and 5000 to 20000 in the case of a thermal plasma arc. ° C.

  The molten glass G manufactured using the air melting apparatus 1 of the present embodiment is not limited in terms of composition as long as it is a glass that can be manufactured by an air melting method. Therefore, any of soda lime glass, mixed alkali glass, borosilicate glass, or alkali-free glass may be used.

In the case of soda lime glass used for building or vehicle plate glass, it is expressed in terms of mass percentage on the basis of oxide, SiO ₂ : 65 to 75%, Al ₂ O ₃ : 0 to 3%, CaO: 5 to 5%. 15%, MgO: 0~15%, Na 2 O: 10~20%, K 2 O: 0~3%, Li 2 O: 0~5%, Fe 2 O 3: 0~3%, TiO 2: _{0~5%, CeO 2: 0~3%} , BaO: 0~5%, SrO: 0~5%, B 2 O 3: 0~5%, ZnO: 0~5%, ZrO 2: 0~5 %, SnO ₂ : 0 to 3%, SO ₃ : 0 to 0.5%.

In the case of alkali-free glass used for a substrate for a liquid crystal display, SiO ₂ : 39 to 75%, Al ₂ O ₃ : _{3 to} 27%, B ₂ O ₃ : 0 in terms of mass percentage based on oxide. It is preferable to have a composition of -20%, MgO: 0-13%, CaO: 0-17%, SrO: 0-20%, BaO: 0-30%.

In the case of a mixed alkali glass used for a substrate for a plasma display, it is expressed in terms of mass percentage on the basis of oxide, and SiO ₂ : 50 to 75%, Al ₂ O ₃ : 0 to 15%, MgO + CaO + SrO + BaO + ZnO: 6 to 24 %, Na ₂ O + K ₂ O: 6 to 24%.

As other applications, in the case of borosilicate glass used in heat-resistant containers or physics and chemistry instruments, etc., the oxide percentage-based mass percentage display is SiO ₂ : 60 to 85%, Al ₂ O ₃ : 0 to 5%. B ₂ O ₃ : 5 to 20%, Na ₂ O + K ₂ O: 2 to 10%.

The molten glass having a hardly-melted composition manufactured using the in-flight melting apparatus 1 of the present embodiment is obtained by expressing the glass composition after melting in terms of mass percentage on the basis of oxide, SiO ₂ : 61.5 to 66.0%, Al _{2 O 3: 19~24%, B} 2 O 3: 0~1.2%, MgO: 3~8%, CaO: 0~7%, SrO: 0~9%, BaO: 0~1%, MgO + CaO + SrO + BaO : 10 to 19%, and the composition can be made substantially free of alkali metal oxide. Said glass composition is a hard-to-melt glass compared with a general soda-lime glass, and has a high effect by an air melting method. Although it is difficult to reduce bubbles even if it can be melted, it is preferable to use the in-flight melting device of this embodiment because it can not only melt but also reduce bubbles.

The molten glass having a hardly-melted composition manufactured using the in-air melting apparatus 1 of the present embodiment has a glass composition after melting, expressed in mass percentage on the basis of oxide, SiO ₂ : 61.5 to 64.0%, Al ₂ O ₃ : 20 to 23%, B ₂ O ₃ : 0 to 1%, MgO: 3 to 8%, CaO: 1 to 7%, SrO: 3 to 9%, BaO: 0 to 1%, MgO + CaO + SrO + BaO: 12 It is -18% and can be set as the composition which does not contain an alkali metal oxide substantially. Said glass composition is more preferable from the physical property as display glass, productivity, and another viewpoint.

The molten glass having a hardly-melted composition manufactured using the in-air melting apparatus 1 of the present embodiment has a glass composition after melting, expressed in mass percentage on the basis of oxide, SiO ₂ : 61.5 to 64.0%, Al ₂ O ₃ : 20 to 23%, B ₂ O ₃ : 0 to 1%, MgO: 4 to 8%, CaO: 2 to 6%, SrO: 3 to 9%, BaO: 0 to 1%, MgO + CaO + SrO + BaO: 13 It is -18% and can be set as the composition which does not contain an alkali metal oxide substantially. The above glass composition is particularly preferable from the viewpoints of physical properties, productivity and other aspects as display glass.

In the air melting method performed in the present embodiment, the glass raw material of any one of the above compositions, for example, the particulate glass raw material of each component described above is mixed according to the composition ratio of the target glass, and the granulated body and Prepared glass raw material particles 2 are prepared.
Basically, the air melting method is a method of manufacturing glass by melting glass raw material particles 2 in order to manufacture glass composed of a plurality of (usually three or more components) components.

For example, when an example of an alkali-free glass is applied as an example of the glass raw material particle 2 described above, silica sand, alumina (Al ₂ O ₃ ), boric acid (H ₃ BO ₃ ), magnesium hydroxide (Mg (OH ₂ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), zircon (ZrSiO ₄ ), stalk (Fe ₂ O ₃ ), strontium chloride (SrCl ₂ ) and other glass raw materials for the composition ratio of the target glass The glass raw material particles 2 can be obtained as a granulated body of about 30 to 1000 μm, for example, by a spray dry granulation method.

  As a method for preparing the glass raw material particles 2 from the glass raw material, a method such as a spray dry granulation method can be used, and a granulation method in which an aqueous solution in which the glass raw material is dispersed and dissolved is sprayed in a high temperature atmosphere and dried and solidified. preferable. Further, this granulated body may be composed only of raw materials having a mixing ratio corresponding to the target glass component composition, but the granulated body is further mixed with glass cullet powder having the same composition, and this is mixed with glass. It can also be used in combination with raw material particles.

As an example of a method for obtaining glass raw material particles 2 by spray-dry granulation, a glass raw material in the range of 2 μm to 500 μm is dispersed in a solvent such as distilled water as a glass raw material for each of the above components to form a slurry, The slurry is stirred for a predetermined time by a stirring device such as a ball mill, mixed, and pulverized to obtain glass raw material particles 2 in which the glass raw materials of the above-described components are dispersed almost uniformly.
In addition, when stirring the above-mentioned slurry with a stirrer, the binder such as 2-aminoethanol and PVA (polyvinyl alcohol) is mixed and stirred for the purpose of improving the uniform dispersion of the glass raw material and the strength of the granulated raw material. Is preferred.
The glass raw material particles 2 used in the present embodiment can be formed by a dry granulation method such as a tumbling granulation method or a stirring granulation method in addition to the spray dry granulation method described above.

As for the average particle diameter (weight average) of the said glass raw material particle 2, 30-1000 micrometers is preferable. More preferably, glass raw material particles 2 having an average particle diameter (weight average) in the range of 50 to 500 μm are used, and glass raw material particles 2 in the range of 70 to 300 μm are more preferable. An example of this glass raw material particle 2 is shown in a dotted circle in FIG. The glass raw material particles preferably have a composition ratio that substantially matches or approximates the composition ratio of the final target glass in one glass raw material particle 2.
The average particle size (weight average) of the molten glass particles obtained by melting the glass material particles 2 is usually about 80% of the average particle size of the glass material particles in many cases. The particle diameter of the glass raw material particles 2 is preferably selected from the above-mentioned range from the viewpoint of being able to heat in a short time and facilitating the diffusion of the generated gas, from the viewpoint of reducing the composition variation between the particles.

Moreover, these glass raw material particles 2 can contain a clarifying agent, a coloring agent, a melting aid, an opacifier, etc. as an auxiliary raw material as needed. In addition, boric acid and the like in these glass raw material particles 2 have a relatively high vapor pressure at a high temperature, and are thus easily evaporated by heating. Therefore, it may be mixed in excess of the composition of the glass as the final product. it can.
In this embodiment, when a clarifier is contained as an auxiliary material, a necessary amount of a clarifier containing one or more elements selected from chlorine (Cl), sulfur (S), and fluorine (F) is required. Can be added.
Also, conventionally used fining agents such as Sb and As oxides, even if the effect of reducing bubbles is generated, these fining elements are undesirable elements in terms of reducing environmental impact, and their use is It is preferable to reduce in view of the direction of reducing the environmental load.

In the in-flight melting apparatus 1 of the present embodiment, glass raw material particles 2 supplied together with a carrier gas such as helium from a raw material supply unit 9 through a supply pipe 10 are, as an example, shown in FIG. It passes through the inside, is heated, forms molten glass particles U, and descends onto the molten glass G staying in the reservoir 6. Here, when the glass raw material particles 2 are melted with high heat in the heated gas phase atmosphere 4 to become the molten glass particles U, helium gas or neon gas is present around the glass raw material particles 2, but these gases are present. By doing so, a clarification effect is exhibited, and it becomes difficult to generate bubbles inside the generated molten glass particles U, and it is possible to generate molten glass particles U with less bubbles.
In making the glass raw material particles into molten glass particles in a heated gas phase atmosphere, the glass raw material particles are at least equal to or higher than the melting start temperature of the glass raw material mixture which is a glass raw material before making the glass raw material particles described later. do it. For example, it is preferable that the glass raw material particles having a hardly fusible glass composition shown in the examples described later are heated to at least 1300 ° C. or higher, and further because the glass raw material particles reach that temperature and melt in a heated gas phase atmosphere. The heating temperature is adjusted in consideration of the heat capacity of the glass raw material particles and the residence time in the heated gas phase atmosphere.

In the present invention, helium gas or neon gas exists in a high-temperature gas phase atmosphere around each glass raw material particle 2 obtained by collecting and granulating the glass raw materials, and in the presence of these gases, Since each grain of the raw material particles 2 becomes molten glass particles in a short time, it is expected that these gases can be effectively taken into the molten glass.
Such a phenomenon can be realized even in a conventional melting method including a Siemens kiln, even by melting using glass raw material particles. For example, the same effect can be obtained if glass raw material particles are put into a kiln instead of a burner that heats a batch type raw material of a Siemens kiln, and is a burner that can be melted in a gas phase atmosphere such as a burner.
However, according to the conventional batch-type melting method described above, melting proceeds from the surface of the lump (batch crest) in which each relatively large glass raw material is mixed, so these gases introduced into the atmosphere are layered on the surface of this lump. In addition, since the temperature inside the lump, that is, the temperature of the glass raw material to be melted is low, the solubility of the physical dissolved gas is low. For this reason, in the conventional melting method, it is expected that helium gas or neon gas cannot be effectively taken into the molten glass as in the present invention.
That is, compared with the case where a mixture obtained by simply mixing the raw materials as described above is melted or compared with the case where helium gas or the like is brought into contact with the glass after melting, according to the present invention, the method unique to the present invention described above is used. Thus, helium gas or neon gas can be taken into the periphery of the glass raw material particles, a clarification effect can be exhibited, and molten glass particles with less bubbles can be produced.

  Moreover, in the molten glass particle U produced | generated by the air melting method by the above-mentioned this invention, even if there are some bubbles, since the bubble diameter can be enlarged, it removes from the bubble with a small bubble diameter when further melting. There is a feature that makes it easy. On the other hand, the molten glass particles obtained by transporting with a conventional granule melting burner using oxygen or air as a carrier gas and melting in the air include helium gas or neon gas, or helium gas or neon gas and oxygen or air. As the carrier gas is used as the carrier gas, bubbles with a smaller bubble diameter than the molten glass produced in the embodiment of the present invention are included, and the total amount of bubbles tends to increase. There is a tendency to contain many small bubbles.

Since the carrier gas composed of at least one of helium gas and neon gas sent from the gas supply source 11 needs to be sufficiently present around the glass raw material particles 2, 100% helium gas or 100% neon gas is preferable. However, since the carrier gas composed of at least one of helium gas and neon gas is supplied together with the fuel gas and the combustion gas, the concentration in the gas phase atmosphere need not be 100%. For example, from the examples described later, the ratio of the volume of these gases to the total volume of the carrier gas increases the clarification effect as the content of these gases increases, and a significant effect is obtained at least 10% or more. Is recognized.
The amount of helium gas or neon gas introduced in the present invention is the size of the glass raw material particles, the rate of introduction of the glass raw material particles into the high temperature gas phase atmosphere, the size of the region of the high temperature gas phase atmosphere, the viscosity of the molten glass, Naturally, it also varies depending on the amount of glass melted per day. For this reason, it should be determined appropriately according to these conditions. For example, from the experimental results to be described later, in order to sufficiently generate a clarification effect when the glass raw material particles 2 are melted, when the glass raw material particles 2 are charged at a rate of 70 g / min, the input of these gases is 5 L / min or more. An amount is preferred. Among these ranges, a range of 10 to 100 L / min is preferable.
In the present invention, since helium or neon exists around each glass raw material particle, the partial pressure of helium and neon does not need to be high. Rather, the upper limit of atmospheric pressure should be determined by relationship to the cost of using these gases.

  The molten glass G does not stay in the reservoir 6 when the glass raw material particles 2 start to be melted in the air, but the molten glass particles U that pass through the heated gas phase atmosphere 4 and descend are deposited in the reservoir. The heated glass atmosphere 4 and the radiant heat from the furnace body 8 are heated to a desired temperature for melting by auxiliary heating means or the like provided in the storage unit 6 if necessary, and the molten glass G Form. Even if the molten glass particles contain some bubbles as described above in a state where the molten glass G is retained in the storage portion 6, the bubbles can be enlarged. Since bubbles having a large diameter are easily floated and removed during the retention in the storage unit 6, bubbles having a large diameter are easily removed before the glass product is made.

Thereafter, the heated molten glass particles U that sequentially descend onto the molten glass G form the molten glass G. And when the molten glass G is discharged | emitted from the discharge port 12 of the furnace body 8 with a predetermined | prescribed speed | rate, and further higher bubble quality is requested | required, it introduce | transduces into a pressure reduction degassing apparatus as needed, and is forced further in a pressure reduction state. After defoaming, it is transferred to the molding device 14 to be molded into a desired shape, and a glass product is manufactured.
Since the glass product manufactured as described above is manufactured based on the molten glass G having a high bubble quality with few bubbles, the glass product is a high-quality glass product with few bubbles.

FIG. 4 is a cross-sectional view showing another embodiment of the granulated body melting burner 3 provided in the furnace body 8 of the previous embodiment. The granulation melt burner 30 of this embodiment includes a cylindrical nozzle body 31 having a supply path 31a for allowing glass raw material particles 2 and helium gas or neon gas to pass therethrough, and a nozzle body outside the nozzle body 31. A six-pipe structure comprising a first outer tube 32, a second outer tube 33, a third outer tube 34, a fourth outer tube 35, and a fifth outer tube 36, which are sequentially arranged so as to surround 31; Has been.
A fuel gas supply path 32a is formed between the nozzle body 31 and the first outer pipe 32, and a primary oxygen supply path 33a is formed between the first outer pipe 32 and the second outer pipe 33, A secondary oxygen supply path 34 a is formed between the second outer tube 33 and the third outer tube 34. Further, a cooling water channel 35 a is formed between the third outer tube 34 and the fourth outer tube 35, and a cooling water channel 36 a is formed between the fourth outer tube 35 and the fifth outer tube 36. Yes.
A diffusion plate 32A is formed at the tip of the nozzle body 32 so as to close the tip of the nozzle body 32, and a combustion chamber 37a is formed at the tip of the diffusion plate 32A surrounded by a trumpet type partition wall 37. Further, the diffusion plate 32A is formed with a raw material jet 32b that communicates the nozzle body 31 and the combustion chamber 37a, and the partition 37 of the combustion chamber 37a has a first injection port for communicating with the fuel gas supply path 32a, respectively. 32b, a second injection port 33b for communicating with the primary oxygen supply path 33a, and a plurality of third injection ports 34b for communicating with the secondary oxygen supply path 34a are respectively formed so as to surround the combustion chamber 37a. ing. The cooling water passages 35a and 36a are connected in communication in a folded state between the front end portion of the third outer pipe 34 and the front end portion of the fifth outer pipe 36, and a coolant such as cooling water is circulated between the two water passages. It is configured to be able to.

  Also in the granulated melt burner 30 of the present embodiment, an oxyfuel flame can be generated in the same manner as the granulated melt burner 3 of the previous embodiment, and the granulated melt burner 3 shown in FIG. Similarly, it is attached to the furnace body 8 so as to penetrate the ceiling portion 8A, and an oxygen combustion flame can be blown out from the tip of the granulated body melting burner 30 as in the previous embodiment.

  Even in the granulated melt burner 30 of the present embodiment, a heated gas phase atmosphere composed of a combustion flame is generated, and the glass raw material particles 2 in a state of being conveyed by a carrier gas of helium gas or neon gas are nozzleed therein. It can be supplied from the main body 31 and melted to generate the molten glass particles U, and the molten glass G can be generated.

FIG. 5 is a flowchart showing an example of a method for producing a glass product using the air melting method according to the present invention.
In order to manufacture the glass product 15 according to the method shown in FIG. 5, if the molten glass G is obtained by the glass melting step S <b> 1 using the above-described air melting apparatus 1, the molten glass G is transferred to the molding apparatus 14. The glass product 15 can be obtained by passing through a molding step S2 for feeding into a desired shape, followed by slow cooling in the slow cooling step S3 and cutting to a required length in the cutting step S4.
In addition, the process of grind | polishing the molten glass after shaping | molding is provided as needed, and a glass product can be manufactured.
According to the above-described glass product manufacturing method, for example, architectural glass plates, vehicle glass plates, liquid crystal display glass substrates, plasma display glass substrates, and the like can be manufactured.

FIG. 6 shows one embodiment of an apparatus for manufacturing glass beads (glass particles) by carrying out the air melting method according to the present invention. The manufacturing apparatus 40 of the present embodiment includes a plasma generating coil 41 and its A granule melting burner (raw material heating unit) 42 disposed on the upper side and a storage unit 43 installed on the lower side of the plasma generating coil 41 are configured.
The plasma generating coil 41 is disposed along the outer periphery of a vertical cylindrical frame 45, and a granule melting burner 42 is vertically supported on the upper side of the frame 45, and the granule melting burner 42 has a lower end thereof. It arrange | positions downward so that the center part of the upper part side of the flame | frame 45 may be desired.
A raw material supplier 47 composed of a hopper containing the glass raw material particles 2 is connected to the upper end portion of the granulated body melting burner 42 through a supply pipe 46. A gas supply source 48 for supplying a fuel gas such as propane gas and a combustion gas such as oxygen gas is connected to the granulated melt burner 42 via supply pipes 49a and 49b. A gas supply source (supply unit) 50 capable of supplying at least one of helium gas and neon gas is connected through a supply pipe 51 in the middle of the above.

In the apparatus of this embodiment, the glass raw material particles 2 can be supplied from the raw material supplier 47 to the granulated body melting burner 42 via the supply pipe 46. Further, at least one of helium gas and neon gas from a gas supply source 50 is supplied through a supply pipe 51 connected to a part of the supply pipe 46, and the glass raw material particles 2 are melted by using these gases as a carrier gas. The burner 42 can be supplied.
The granulated melt burner 42 may be a granulated melt burner having a triple structure equivalent to the granulated melt burner 3 described in the previous embodiment, or 6 equivalent to the granulated melt burner 30 described above. A granulated melt burner with a heavy structure may be used. Regardless of the structure, the glass raw material particles 2 can be supplied to the center side of the burner while being transported by at least one carrier gas of helium gas and neon gas. The glass raw material particles 2 can be continuously supplied to the oxyfuel flame 42a generated by the granulated molten burner 42.
The glass raw material particles 2 may be supplied to the flow path on the center side of the granulated melt burner 42 having a triple structure or a 6-fold structure. Of course. As long as the glass raw material particles 2 can be reliably supplied to the generated combustion flame regardless of the flow path on either side, the glass raw material for the central and external flow paths of the granulated melt burner 42 is used. The supply route of the particle | grains 2 is not ask | required.

An argon gas or air supply source 53 is connected to the upper portion of the vertical cylindrical frame 45 to which the plasma generating coil 41 is attached via a supply pipe 52, and a plasma oscillator 55 and an operation panel 56 are connected to the plasma generating coil 41. And are connected.
The manufacturing apparatus 40 of the present embodiment includes a plasma generating coil 41, a frame 45, a supply source 53, a plasma oscillator 55, and an operation panel 56 to constitute a high frequency plasma apparatus (thermal plasma arc generating apparatus) 57. The high-frequency plasma apparatus 57 is operated, that is, a high-frequency thermal plasma arc is generated inside the frame 45 by applying a high frequency from the plasma oscillator 55 to the plasma generating coil 41.
The lower side of the frame 45 is connected to the opening of the ceiling portion 43 </ b> A of the accommodating portion 43 through a downward trumpet-shaped connecting wall 58, and the internal space of the frame 45 is communicated with the internal space of the storage portion 43. Inside the storage unit 43, a transport carriage 62 including a bucket-shaped storage unit 61 made of stainless steel is accommodated. Moreover, although not shown in figure, the housing | casing surface of the storage part 43 is cooled with the cooling water. Further, an exhaust gas treatment device 65 is connected to the side wall portion of the housing portion 43 via an exhaust pipe 63.

Although omitted in FIG. 6, an opening / closing door capable of sealing the accommodation portion 43 is formed on the side wall portion of the accommodation portion 43, and the transport carriage 62 opens the opening / closing door to open the accommodation portion. 43 can be moved to the outside.
Further, the frame 45 including the plasma generating coil 41, the connection wall 58 below it, and the storage portion 43 below it are integrally formed continuously, and working gas such as argon gas is supplied from the supply source 53 to the inside of the frame 45. Is supplied, a high frequency is applied from the plasma generating coil 41, the working gas is ionized and plasma ignition is performed, so that a high frequency thermal plasma arc (plasma flame) can be generated on the center side of the frame 45.

  The manufacturing apparatus 40 shown in FIG. 6 uses the oxyfuel combustion flame 42a generated from the granulated melt burner 42 and the high-frequency thermal plasma arc generated by the plasma generating coil 41 as needed, and creates a heated gas phase atmosphere consisting of either one. The glass raw material particles 2 are melted to form molten glass particles.

  As in the case of the above-described embodiment, the glass raw material particles 2 are put into a heated gas phase atmosphere consisting of a combustion flame or a high-frequency thermal plasma arc together with at least one of helium gas and neon gas. It can be melted in the middle to obtain molten glass particles. The glass beads 66 can be obtained by dropping the molten glass particles into the stainless steel storage unit 61 and cooling. Therefore, the storage unit 61 is a cooling unit that cools the molten glass particles in the apparatus of the present embodiment. In the apparatus of the present embodiment, the storage unit 61 and the transport carriage 62 are not essential, and these may be omitted, and a structure for receiving the molten glass particles on the floor 43B of the storage unit 43 may be used. The internal space and the floor portion 43B constitute a cooling unit that cools the molten glass particles.

Glass beads 66 manufactured by the manufacturing apparatus 40 shown in FIG. 6 are melted by an air melting method in which glass raw material particles are introduced into a combustion flame or a high-frequency thermal plasma arc together with at least one of helium gas and neon gas, and helium gas and neon gas. After being made into molten glass particles with less bubbles by the clarification effect by at least one of the above, it is cooled in the reservoir 61 and obtained by cooling molten glass particles with high bubbles quality with few bubbles, High glass beads 66 are obtained.
The glass beads thus obtained can be used as glass beads as they are, used by being mixed with other raw materials, or put into a glass melting furnace and used.

FIG. 7 shows an embodiment of an apparatus for manufacturing molten glass by carrying out an air melting method according to the present invention. The manufacturing apparatus 70 of this embodiment is arranged on the plasma generating coil 41 and the upper side thereof. The granulated body melting burner 42 and a reservoir 71 installed on the lower side of the plasma generating coil 41 are configured. There is a furnace bottom 80 at the bottom of the reservoir 71.
The manufacturing apparatus 70 having the configuration shown in FIG. 7 has a structure similar to that of the manufacturing apparatus 40 of the previous embodiment. The storage unit 43 of the previous apparatus is changed to a storage unit 71 of molten glass G2, and the storage unit 71 The difference is that the molding apparatus 14 is connected. Other configurations are the same as the configuration of the manufacturing apparatus 40 shown in FIG. 6, and the same elements are denoted by the same reference numerals, and the description of the same elements is omitted.
The storage unit 71 is made of a refractory material such as a refractory brick, and is configured to store high-temperature molten glass G2. The connecting wall 58 and the frame 45 are installed on the ceiling portion 71 </ b> A in the storage portion 71, and the combustion flame generated by the granule melting burner 42 installed on the upper side of the frame 45 is generated inside the storage portion 71. Generated to be able to reach the side.

Although not shown, the heater 71 is installed in the storage unit 71 so that the molten glass G2 stored in the storage unit 71 can be held in a molten state at a target temperature (for example, about 1400 ° C.).
A discharge port 72 is formed in a part of the side wall of the storage unit 71, and the discharge port 72 is connected to the molding device 14 similarly to the configuration shown in FIG. 2, and the molten glass G2 stored in the storage unit 71 is removed by the molding device 14. It is configured so that it can be molded into the desired shape.
Further, an exhaust gas treatment device 65 is connected to the side wall portion of the storage portion 71 via an exhaust pipe 63.

According to the manufacturing apparatus 70 having the configuration shown in FIG. 7, the glass raw material particles 2 are melted in the air by introducing the glass raw material particles 2 into a combustion flame or a high-frequency thermal plasma arc together with at least one of helium gas and neon gas. Glass particles can be used. And this molten glass particle can be obtained by dropping in the direction of the furnace bottom 80 of the storage part 71 made of refractory bricks and storing it as the molten glass G2, thereby obtaining a molten glass G2 having a high bubble quality with few bubbles.
This molten glass G2 is discharged from the discharge port 72 at a predetermined speed, introduced into a vacuum degassing device as necessary, and further degassed forcibly in a reduced pressure state, and then transferred to the molding device 14 to a desired shape. Can be molded to produce glass products.
Since the glass product manufactured as described above is manufactured based on the molten glass G2 having a high bubble quality with few bubbles, as in the previous embodiment, it is possible to obtain a high-quality glass product with a small number of bubbles. it can.
In the above, the air melting method and apparatus of the embodiment of the present invention have been described. However, the present invention is not limited to the air melting method as long as the glass raw material particles can be melted in a high-temperature gas phase atmosphere. That is, instead of batch-type glass raw material in a Siemens kiln, glass raw material particles are melted in a gas phase atmosphere using glass raw material particles and in the presence of at least one of helium gas and neon gas, As long as it is a molten glass raw material particle, it has the same effect and is within the scope of the present invention.

  An alkali-free glass having the composition shown in Table 1 below was produced by an air melting method as one method for melting glass raw material particles in a heated gas phase atmosphere. These glass compositions are alkali-free glass (A), alkali-free glass (B), and alkali-free glass (C) having a composition ratio recognized as hardly melted glass as compared with general soda lime glass. For example, the melting start temperature in the case of a glass raw material mixture having a composition ratio of alkali-free glass (A) is 1152 ° C. The melting start temperature in the case of a glass raw material mixture having a composition ratio of alkali-free glass (B) is 1362 ° C. The melting start temperature in the case of a glass raw material mixture having a composition ratio of alkali-free glass (C) is 1376 ° C. The alkali-free glass (B) is a glass having a hardly meltable composition ratio as compared with the alkali-free glass (A). The alkali-free glass (C) is a glass having a hardly meltable composition ratio as compared with the alkali-free glass (B). The melting start temperature is obtained by adding 250 g of a raw material mixture, which is a glass raw material before making glass raw material particles, to a platinum board having a length of 400 mm and a width of 20 mm and heating in a furnace with a temperature gradient of 800 to 1500 ° C. for 1 hour. The temperature at which more than half of the raw material was vitrified visually was determined.

As glass raw materials for melting glass, silica sand, alumina, boric acid (H ₃ BO ₃ ), magnesium hydroxide, calcium carbonate, strontium carbonate, zircon, petiole (Fe ₂ O ₃ ), and strontium chloride were prepared. . These raw materials were prepared so as to have a target glass composition. The particle sizes of these raw materials were measured using a dry laser diffraction / scattering particle size / particle size distribution measuring device (Microtrac MT3300: trade name, manufactured by Nikkiso Co., Ltd.). The results are shown in Table 2.

  The “particle size” described in the present example is a sphere equivalent diameter, and specifically refers to the particle size in the particle size distribution of each raw material measured by the measuring device. The particle size D50 (median particle size) refers to the particle size when the cumulative frequency is 50% in the particle size distribution of each raw material measured by this measuring apparatus.

  2 kg of the raw material batch prepared as described above was mixed with 3 liters of distilled water (solvent) to form a slurry. For the purpose of dispersing the raw material in the slurry and improving the strength of the glass raw material particles, 0.5% of 2-aminoethanol is used as a pH adjuster for the alkali-free glass (A) with respect to the raw material batch, and nothing. 1% of PVA (polyvinyl alcohol) was added to the alkali glass (B). These slurries were mixed at 40% solids concentration (solvent is water) and mixed and ground for 1 hour using alumina balls. The alumina ball was a ball having a diameter of 20 mm, and a ball mill equipped with a 10-liter container in which 10 kg of the ball was accommodated was used.

  Spray drying granulation was performed using the obtained slurry. The granulation conditions were a spray dryer manufactured by Pris Co., Ltd., drying chamber diameter: 2600 mm, atomizer rotation speed: 12000 rpm, inlet temperature: 250 ° C., outlet temperature: 120 ° C. Slurry supply amount: 20-25 kg / hour . The average diameter of the glass raw material particles was 78 μm for the alkali-free glass (A) raw material, 74 μm for the alkali-free glass (B) raw material, and 70 μm for the alkali-free glass (C) raw material.

Using the obtained glass raw material particles, a combustion flame was generated from the granulated melt burner using an air melting apparatus having substantially the same configuration as that shown in FIG. 6, and an air melting test was performed. In this test, the transport carriage 62 was not used.
As a carrier gas for the glass raw material particles, compressed air (comparative example) or helium gas (present invention example) 100% gas was used. In addition, for the alkali-free glass (B), the test was also performed when the volume ratio with respect to the total carrier gas including helium gas and air was set to 1, 5, and 10%. The amount of carrier gas was 30 L / min. Glass raw material particles were conveyed at about 70 g / min. The granule melting burner used for melting had a fuel gas flow rate of 25 L / min and a combustion gas flow rate of 117 L / min. The fuel gas used was LPG, and the combustion gas was oxygen.
The molten glass particles that have undergone the air melting test are those in which the glass raw material particles are melted and spheroidized as they are (glass beads), and as such, it is not possible to evaluate the clarity. Furnace melting was performed. Melting was performed at 1400 ° C. for 30 minutes to form a melt, followed by clarification at 1500 ° C. for 30 minutes. The obtained glass was gradually cooled and subjected to double-side polishing to evaluate foam. Foam evaluation was measured as the number of bubbles per bubble per 1 g and the bubble diameter distribution by observing the polished glass under a microscope, and the results are shown in Table 3 below. As a fining agent, chlorine (Cl): 0.5 wt% was added to the alkali-free glass (A), (B), and (C) raw materials.

  A glass obtained by generating a combustion flame from a granule melting burner using an air melting apparatus having the structure shown in FIG. 6, forming glass beads by an air melting method, and melting the glass beads with a platinum crucible. FIG. 8 shows the results of the foam evaluation test. FIG. 8A shows a micrograph of a sample by air conveyance using glass raw material particles having a composition of alkali-free glass (A) and using compressed air (compressed air 100%) as a carrier gas. Shows a photomicrograph of a sample by helium transport using glass raw material particles having a composition of alkali-free glass (A) and helium (100% helium gas) as a carrier gas. FIG. 8C shows a micrograph of a sample by air conveyance using glass raw material particles having a composition of alkali-free glass (B) and using compressed air (compressed air 100%) as a carrier gas. Shows a photomicrograph of a sample by helium transport using glass raw material particles having a composition of alkali-free glass (B) and helium (100% helium gas) as a carrier gas. The micrographs in FIGS. 8A to 8D have the same magnification, and a scale of 1 mm is shown in FIG. 8D. Further, Table 3 shows details of the bubble diameter distribution of each sample.

  As shown in FIG. 8, the bubble diameter and the number of bubbles in glass melted by remelting glass beads using helium as a carrier gas were determined by reusing molten glass particles (glass beads) conveyed by air using compressed air. Compared with the melted glass, expansion of the bubble diameter and decrease in the number of bubbles were observed.

From the results shown in Table 3, it can be seen that the total number of bubbles is greatly reduced by replacing air transportation with helium transportation. In particular, the effect is remarkable in the alkali-free glass (B) having a glass composition ratio which is hardly melted. In addition, in the distribution of the bubble diameter of the alkali-free glass (A), the sample obtained by air conveyance has predominantly small diameter bubbles (for example, 50 μm or less), whereas the sample obtained by helium conveyance is Large bubbles with a diameter of 100 to 150 μm are increasing. This is also apparent from the photo contrast in FIG. That is, when manufacturing glass by melting glass raw material particles by an air melting method, it means that the bubble diameter can be increased by changing from air conveyance to helium conveyance. From the photographs showing the test results, the glasses shown in FIGS. 8B and 8D seem to have a larger volume of bubbles than the glasses shown in FIGS. 8A and 8C. However, when glass products are actually manufactured, after defoaming treatment in a melting furnace or the like before forming with a forming apparatus, the glass products are formed into a target shape. A defoaming process is performed. In the defoaming process, it is desirable that the glass has a large bubble diameter because bubbles can be lifted and the bubbles can be reliably removed.
Further, from the result of changing the proportion of helium in the alkali-free glass (B) shown in Table 3, although the number of bubbles is increased when the proportion of helium is 1%, the bubbles are increased as the proportion of helium thereafter increases. The total number of is clearly decreasing. Furthermore, even in the alkali-free glass (C) that exhibits the least solubility, a remarkable phenomenon of bubbles is observed by carrying helium.

  Table 4 below shows the measurement results of the specific gravity, Young's modulus, strain point, and glass transition point of alkali-free glass (A), (B), and (C) produced by the previous helium conveyance (100% helium gas conveyance). Show.

  As shown in Table 4, the non-alkali glass (B) and the non-alkali glass (C) improve the strain point with respect to the non-alkali glass (A) and reduce the strain even when heat-treated at a higher temperature. Glass. For example, even if a TFT capable of high-speed operation as a switching element for a display device is formed on a glass substrate, the TFT is used under a condition of heat treatment at a temperature exceeding 700 ° C., for example, about 720 ° C. for about 10 to 20 minutes. If it is alkali-free glass (B) and alkali-free glass (C), a glass substrate that does not cause a problem during heat treatment can be provided.

Next, for reference, an electric furnace melting test was performed in a helium gas atmosphere. In this test, a glass raw material blended in a desired composition is housed in a crucible, and a predetermined amount (3 L / min) of helium gas (100%) is allowed to flow through the atmosphere in which the crucible is installed to obtain a 100% helium gas flow rate atmosphere. This is a test in which a crucible is heated to melt a glass raw material to obtain a molten glass.
First, 200 g of raw material batch was prepared. The batch raw materials used in this test are silica sand, boric acid (H ₃ BO ₃ ), alumina, magnesium hydroxide, dolomite, strontium carbonate, zircon, petal (Fe ₂ O ₃ ), and strontium chloride particles. Samples having the respective compositions of alkali-free glass (A) and alkali-free glass (B) shown above were prepared.

  Table 2 shows the particle sizes of the batch raw materials (raw materials used in the reference example test). The obtained blended raw material batch was melted at 1400 ° C. for 30 minutes using a platinum crucible to be melted, and further clarified at 1500 ° C. for 30 minutes to obtain a glass of reference example. The obtained glass was gradually cooled and subjected to double-side polishing to evaluate foam. As a result, the number of bubbles was 4468 / g in the case of the composition of alkali-free glass (A), and 5472 / g in the case of the composition of alkali-free glass (B). In any sample, Cl; 0.5% by weight is added as a fining agent.

From the above results, the glass obtained by transporting the glass raw material particles in helium and melting in the gas phase atmosphere as in the present invention was obtained by the normal melting method in the helium atmosphere performed for the above-mentioned reference. It can be seen that the number of bubbles can be reduced even when compared with the glass obtained by comparing the glass raw material particles with the glass obtained by conveying the raw material particles with compressed air and melting them in a gas phase atmosphere. The reason for this is that when molten glass is produced by performing normal melting in a melting furnace, even if helium gas is filled in the upper space of the melting furnace for melting the molten glass for controlling the atmosphere, the molten glass remains on the surface. Since only helium gas is touched, the clarification effect of helium gas on the molten glass is limited.
On the other hand, when glass raw material particles are melted while being surrounded by helium gas in a gas phase atmosphere, each glass raw material particle is melted, and helium gas is surely contained in a high-temperature atmosphere in which molten glass particles exist. Since the contact area between the individual glass raw materials and the helium gas during melting is much larger than the melting method using a normal melting furnace, the clarification effect of the helium gas is sufficiently exerted. This is thought to have contributed to the reduction of the number. Similarly, when neon gas is used instead of helium gas, it can be assumed that it contributes to the reduction of the number of bubbles. In addition, it turns out that there exists an effect of expansion of the bubble diameter demonstrated previously for the same reason.

  Next, in order to show that molten glass obtained by melting glass raw material particles using helium carrier gas effectively incorporates helium, analysis of gas generated from glass beads by the air melting method, which is an intermediate stage in the production of molten glass Carried out.

The analysis method was TDS (Thermal Desorption Spectrometry). That is, the sample was heated in a state of being wrapped in a Pt foil, the back pressure at the start of measurement: about 2 × 10 ⁻⁷ Pa, the rate of temperature increase: (1) 20 ° C./min (room temperature to 800 ° C.) (2) Hold at 800 ° C. for 10 minutes (3) 10 ° C./minute (800-1000 ° C.), maximum temperature: 1000 ° C., ions generated from the heated sample are separated by mass-to-charge ratio in a mass spectrometer and the presence of helium The peak having an m / z of 4 was counted. The analysis results for each sample are shown in FIGS.

FIG. 9 shows a temperature desorption gas profile (room temperature to 500 ° C.) of a glass sample by melting in the air. FIG. 10 shows a temperature-programmed desorption gas profile (room temperature to 1000 ° C.) of a glass sample obtained by normal melting in a helium gas atmosphere. 9 and 10 is a non-alkali glass (B).
As shown in FIG. 9, the glass bead remelt glass obtained by carrying helium (the ratio of helium to the carrying gas is 100%) shows the presence of helium ions during the temperature rise from room temperature to 500 ° C. A peak with z of 4 was detected with a slight weakness. On the other hand, in the molten glass obtained by normal melting in a helium gas atmosphere, no peak having an m / z of 4 is detected at all as shown in FIG. From this, it was found that helium remained in the glass beads obtained by conveying the glass raw material particles with helium by the air melting method. That is, it was confirmed that the effect of expanding the bubble diameter and decreasing the number of bubbles recognized by the present invention was the effect of helium when the air melting method was performed.
Neon gas is known as a gas having the same properties as helium gas, and it is clear that the same effect as the above-described helium gas can be obtained.

The technology of the present invention can be widely applied to the production of glass for building materials, glass for vehicles, optical glass, medical glass, glass for display devices, glass beads, and other general glass products.
It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2010-222305 filed on September 30, 2010 are incorporated herein as the disclosure of the present invention. .

  G ... Molten glass, U ... Molten glass particle, 1 ... In-air melting device, 2 ... Glass raw material particle, 3 ... Granule fusion burner (raw material heating part), 3a ... Combustion flame, 4 ... Heated gas phase atmosphere, 5 DESCRIPTION OF REFERENCE SYMBOLS: Heated gas-phase atmosphere formation region, 6 ... storage part, 7 ... arc electrode, 8 ... furnace body, 9 ... raw material supply part, 10 ... supply pipe, 11 ... gas supply source (supply part), 14 ... molding apparatus, 15 DESCRIPTION OF SYMBOLS ... Glass product, 22 ... Nozzle main body, 25, 26 ... Gas supply path, 30 ... Granule fusion burner (raw material heating part), 31 ... Supply path, 32 ... Nozzle main body, S1 ... Glass melting process, S2 ... Molding process , S3 ... Slow cooling step, S4 ... Cutting step, 40 ... Manufacturing device, 41 ... Plasma generating coil, 42 ... Granule melting burner (raw material heating part), 43 ... Storage part, 47 ... Raw material feeder, 48 ... Gas Supply source, 50 ... gas supply source (supply unit), 51 ... supply pipe, 52 Supply pipe, 57 ... high frequency plasma apparatus (thermal plasma arc generator), 61 ... storage part (cooling part), 63 ... exhaust pipe, 65 ... exhaust gas treatment apparatus, 66 ... glass beads, 70 ... manufacturing apparatus, 71 ... storage part 80 ... bottom of furnace, G2 ... molten glass.

Claims (16)

  When glass raw material particles formed by granulating glass raw materials composed of a plurality of components are used and heated and melted by sending the glass raw material particles into a heated gas phase atmosphere, the glass raw material particles are at least one of helium gas and neon gas. And a glass raw material melting method, wherein the glass raw material is sent into the heated gas phase atmosphere.   The glass raw material melting method according to claim 1, wherein the glass raw material particles are melted into molten glass particles in the heated gas phase atmosphere.   The glass raw material melting method according to claim 2, wherein at least one of an oxyfuel flame and a thermal plasma arc is used as the heating gas phase atmosphere. Glass composition after melting by mass percentage based on _{oxides, SiO 2: 61.5~66.0%, Al} 2 O 3: 19~24%, B 2 O 3: 0~1.2%, MgO : 3 to 8%, CaO: 0 to 7%, SrO: 0 to 9%, BaO: 0 to 1%, MgO + CaO + SrO + BaO: 10 to 19%, and a composition substantially free of alkali metal oxides Item 4. A method for melting glass raw material according to Item 2 or 3.   The glass raw material melting method according to any one of claims 1 to 4, wherein the glass raw material particles are sent to a heated gas phase atmosphere together with at least one of the helium gas and neon gas and a fuel gas for forming an oxyfuel flame.   The glass raw material melting method according to any one of claims 1 to 5, wherein the glass raw material particles and glass cullet fine powder are mixed and sent to a heated gas phase atmosphere.   The manufacturing method of the molten glass which stores this molten glass by making the said glass raw material particle into a molten glass by making it melt | dissolve in a heating gas-phase atmosphere using the melting method of the glass raw material as described in any one of Claims 1-6. .   A method for producing glass beads, which is made into glass beads by cooling the glass raw material particles in a heated gas phase atmosphere using the glass raw material melting method according to any one of claims 1 to 6. .   A glass melting step in which the glass raw material particles are heated to form molten glass using the glass raw material melting method according to any one of claims 1 to 6, a step of molding the molten glass, and after molding A method for producing a glass product, comprising a step of slowly cooling the glass.   A glass melting step using the glass raw material particles according to claim 9 as a molten glass includes a step of melting the glass raw material particles in a gas phase atmosphere to form molten glass particles, and a glass obtained by accumulating the molten glass particles. The manufacturing method of the glass product including the process made into a melt. An air melting device that heats and melts glass raw material particles formed by granulating a glass raw material composed of a plurality of components into molten glass particles,
A raw material heating section for forming a heated gas phase atmosphere for heating and melting the glass raw material particles;
A raw material supply unit for supplying the glass raw material particles to the heated gas phase atmosphere;
A supply part for supplying at least one of helium gas and neon gas to the glass raw material particles supplied to the raw material heating part and the molten glass particles;
An in-flight melting apparatus.   The in-flight melting apparatus according to claim 11, wherein the raw material heating unit for forming the heated gas-phase atmosphere is composed of at least one of a granule melting burner and a thermal plasma arc generator.   The in-flight melting apparatus according to claim 11 or 12, wherein a storage unit for molten glass particles is provided so as to communicate with the raw material heating unit.   The in-flight melting apparatus according to claim 11 or 12, wherein a cooling unit and a storage unit for glass beads are provided so as to communicate with the raw material heating unit.   Using glass raw material particles obtained by granulating a glass raw material composed of a plurality of components, and sending the glass raw material particles together with at least one of helium gas and neon gas in a heated gas phase atmosphere, Glass beads obtained by melting glass raw material particles to form molten glass particles, and taking them out from the heated gas phase atmosphere as glass beads after melting, comprising at least one of helium and neon.   The glass bead according to claim 15, wherein the helium and / or neon is confirmed from a peak count in a temperature programmed desorption analysis.

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