Method for manufacturing glass melt and glass melt manufacturing device

Abstract

To provide a method for manufacturing glass melt and the like that are manufactured from a glass-making feedstock and have excellent heating efficiency.SOLUTION: A method for manufacturing glass melt includes a glass melt formation step of directly irradiating a glass-making feedstock stored in a melting container having an opening with an electromagnetic wave from the opening of the melting container to melt the glass-making feedstock and obtain glass melt.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for producing a glass melt and a glass melt production apparatus capable of performing the production method.

Background Art

[0002] Glass products such as optical glass are usually produced by accommodating glass raw materials (batch raw materials or cullets) in a melting container (such as a crucible) made of platinum or quartz, heating and melting to produce a glass melt, performing vitrification and reheating and melting if necessary, and then flowing the glass melt into a mold or the like and cooling and molding it through a process.

[0003] And for this heating and melting, a heating method using an external heat source such as a burner method or an electric heater method is generally used. For example, in Patent Document 1, in a method for producing molten glass in which glass raw material particles are put into a heated gas phase atmosphere formed by an air melting burner to obtain molten glass particles, a method for producing molten glass in which the flow rates of the fuel gas and the supporting combustion gas forming the heated gas phase atmosphere and the raw material supply gas supplying the glass raw material ejected into the heated gas phase atmosphere are made equal is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the burner method, the electric heater method, etc. have room for further improvement in terms of heating efficiency and the like. And from the viewpoint of reducing greenhouse gas emissions and the like, the development of a method for producing a glass melt with more excellent heating efficiency is required.

[0006] Therefore, an object of the present invention is to provide a method for producing a glass melt from a glass raw material, etc., which has more excellent heating efficiency.

Means for Solving the Problems

[0007] In order to solve the above problems, the present inventor has intensively studied, and for the glass raw material accommodated in a melting container having an opening, electromagnetic waves are directly irradiated from the opening of the melting container to melt this glass raw material to obtain a glass melt. The present inventor has found that the above problems can be solved by a method for producing a glass melt including a glass melt forming step, and has completed the present invention.

[0008] That is, the present invention is as follows <1> to <14>. <1>A method for producing a glass melt from a glass raw material, comprising: a glass melt forming step of directly irradiating electromagnetic waves from the opening of the melting container to the glass raw material accommodated in the melting container having an opening to melt the glass raw material to obtain a glass melt. A method for producing a glass melt. <2>A preheating step of preheating at least a part of the glass raw material to a temperature of 300°C or higher and 800°C or lower by an external heat source before the glass raw material is accommodated in the melting container, or after the glass raw material is accommodated in the melting container and before the direct irradiation of the electromagnetic waves is performed. The method for producing a glass melt according to <1>. <3>A mixing step of mixing the glass raw material preheated by the preheating step and the glass raw material not preheated before the glass melt forming step. The method for producing a glass melt according to <2>. <4>Furthermore, a raw material replenishing step of mixing the glass melt obtained in the glass melt forming step and a glass raw material not preheated. The method for producing a glass melt according to any one of <1> to <3>. <5>A method for producing a glass melt from a glass raw material not containing a phosphorus compound, comprising: Before accommodating the glass raw material in a melting container having an opening, or after accommodating the glass raw material in the melting container, a preliminary heating step of preliminarily heating at least a part of the glass raw material by an external heat source so that the temperature becomes 300°C or higher and 800°C or lower; A glass melt forming step of directly irradiating the glass raw material preliminarily heated by the preliminary heating step and accommodated in the melting container with electromagnetic waves from the opening of the melting container to melt the glass raw material to obtain a glass melt, is provided. A method for manufacturing a glass melt. <6>A method for manufacturing a glass melt from a glass raw material containing a phosphorus compound, A glass melt forming step of directly irradiating the glass raw material accommodated in a melting container having an opening and not preliminarily heated with electromagnetic waves from the opening of the melting container to melt the glass raw material to obtain a glass melt, is provided. A method for manufacturing a glass melt. <7>The method for manufacturing a glass melt according to any one of <1> to <6>, wherein the frequency of the electromagnetic wave in the glass melt forming step is 50 Hz or higher and 30 GHz or lower. <8>The method for manufacturing a glass melt according to any one of <1> to <7>, wherein the glass raw material is a glass raw material that does not contain either Se or Te. <9>An apparatus for manufacturing a glass melt from a glass raw material, Having a melting container having an opening and an electromagnetic wave irradiator, and a glass melt forming unit that directly irradiates the glass raw material accommodated in the melting container with electromagnetic waves from the opening of the melting container by the electromagnetic wave irradiator to melt the glass raw material to obtain a glass melt. A glass melt manufacturing apparatus. <10>The glass melt manufacturing apparatus according to <9>, further comprising a preliminary heating unit that performs preliminary heating on at least a part of the glass raw material by an external heat source so that the temperature becomes 300°C or higher and 800°C or lower before accommodating the glass raw material in the melting container, or after accommodating the glass raw material in the melting container and before performing the direct irradiation of the electromagnetic wave. <11>Furthermore, before directly irradiating the electromagnetic wave in the glass melt forming section, a mixing section is provided for mixing the glass raw material preheated by the preheating section and the glass raw material not preheated, according to the glass melt manufacturing apparatus described in <10>. <12>Furthermore, a raw material replenishing section is provided for mixing the glass melt obtained in the glass melt forming section and the glass raw material not preheated, according to the glass melt manufacturing apparatus described in any one of <9> to <11>. <13>The frequency of the electromagnetic wave irradiated by the electromagnetic wave irradiator in the glass melt forming section is 50 Hz or more and 30 GHz or less, according to the glass melt manufacturing apparatus described in any one of <9> to <12>. <14>A method for manufacturing a glass melt from a glass raw material and further manufacturing a crystallized glass from the glass melt, A glass melt forming step of directly irradiating the glass raw material accommodated in a melting container having an opening with an electromagnetic wave from the opening of the melting container to melt the glass raw material to obtain a glass melt, After solidifying the glass melt to obtain a glass solid, a crystallized glass forming step of directly irradiating the glass solid with an electromagnetic wave to crystallize the glass solid to obtain a crystallized glass, A method for manufacturing a crystallized glass.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a method for manufacturing a glass melt from a glass raw material with more excellent heating efficiency.

Brief Description of the Drawings

[0010]

Figure 1

Embodiments for Carrying Out the Invention

[0011] The present invention will be described. The present invention relates to a method for producing a glass melt from a glass raw material, comprising a glass melt forming step of directly irradiating electromagnetic waves from an opening of a melting vessel containing the glass raw material to melt the glass raw material and obtain a glass melt. When using a glass raw material that does not contain a phosphorus compound, the present invention further comprises a preheating step of preheating at least a part of the glass raw material to a temperature of 300 °C or higher and 800 °C or lower by an external heat source before or after accommodating the glass raw material in a melting vessel having an opening, and a glass melt forming step of directly irradiating electromagnetic waves from the opening of the melting vessel to the glass raw material preheated by this preheating step and accommodated in the melting vessel to melt the glass raw material and obtain a glass melt. When using a glass raw material containing a phosphorus compound, the present invention may also be a method for producing a glass melt, comprising the above glass melt forming step of directly irradiating electromagnetic waves from the opening of the melting vessel to the glass raw material accommodated in the melting vessel having an opening and not preheated to melt the glass raw material and obtain a glass melt. Furthermore, the present invention also includes a glass melt production apparatus for producing a glass melt from a glass raw material, having a melting vessel with an opening and an electromagnetic wave irradiator, and comprising a glass melt forming section for directly irradiating electromagnetic waves from the opening of the melting vessel to the glass raw material accommodated in the melting vessel by the electromagnetic wave irradiator to melt the glass raw material and obtain a glass melt. Hereinafter, these may also be referred to as "the method for producing a glass melt according to the present invention" and "the glass melt production apparatus of the present invention".

[0012] First, each step and the like of the method for producing a glass melt according to the present invention will be described in detail.

[0013] The glass raw material used in the method for producing a glass melt according to the present invention may be any one or more powders (mixed powders) selected from inorganic oxides, inorganic composite oxides, inorganic fluorides, inorganic hydroxides, inorganic carbonates, inorganic nitrates, inorganic composite salts, organometallic compounds, etc. (batch raw materials), cullets (glass scraps, glass cullets) obtained by vitrifying the batch raw materials after heating and melting, or any mixture thereof. Therefore, the method for producing a glass melt according to the present invention can be applied to either primary melting mainly for heating and melting batch raw materials or secondary melting mainly for reheating and melting cullets, but it is more preferably applied particularly to primary melting or both primary melting and secondary melting.

[0014] There are also no particular limitations on the components contained in this glass raw material (batch raw material, cullet), and any known components (for example, silicon compounds, phosphorus compounds, etc.) used in glass melt production may be included. When mixing a plurality of components, for example, a predetermined inorganic oxide or the like may be weighed so as to have a predetermined stoichiometric ratio, and wet mixing using a ball mill, dry mixing using a dry mixer, or the like may be performed. In addition, from the viewpoint that the effects of the present invention are more easily exhibited, etc., the glass raw material used in the method for producing a glass melt according to the present invention is more preferably a glass raw material that does not contain either Se or Te. Further, from the viewpoint of heating efficiency, etc., it is more preferable to select and adjust the process as described below depending on whether this glass raw material contains a phosphorus compound (a compound containing P) or not.

[0015] <Glass melt forming step> The method for producing a glass melt according to the present invention includes a glass melt forming step of obtaining a glass melt (a melt of a glass raw material) from the above-described glass raw material, in which electromagnetic waves are directly irradiated from the opening of a melting container containing the glass raw material to melt (melt) the glass raw material and obtain a glass melt.

[0016] This melting container is a container for melting glass raw materials. It has an opening and can contain glass raw materials and the glass melt obtained by melting them. Other than this, it is not limited as long as it can achieve this, and for example, a crucible made of platinum or quartz having an opening (a crucible with platinum or quartz as the main component) is shown as a preferable melting container. Here, this "main component" means that its content ratio is more than 50% by mass, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. Also, regarding the arrangement and diameter of the opening, other than this, it is not limited as long as electromagnetic waves can be directly irradiated onto the glass raw materials contained through this opening. For example, those with an opening on the top surface side of the melting container (the side that becomes the top surface when the melting container is placed) are shown.

[0017] And in this glass melt forming step, as described above, the glass raw materials are contained in the above-mentioned melting container, and electromagnetic waves are directly irradiated onto the internal glass raw materials from the opening of this melting container to melt the glass raw materials to obtain a glass melt. That is, the glass raw materials contained in the melting container are heated from the inside by direct irradiation of electromagnetic waves (direct induction heating, direct induction melting) to a temperature above the melting temperature (for example, 1200 °C or higher) to form a glass melt. Thereby, the method for manufacturing a glass melt according to the present invention has better heating efficiency (it is possible to shorten the time, save energy, etc.) than the method for manufacturing a glass melt only by heating from an external heat source. Here, this "direct irradiation" means that the electromagnetic wave irradiated from the irradiation source is directly irradiated onto the glass raw material without being reflected or transmitted by other objects (mainly solids) excluding the atmosphere. Also, as long as a glass melt can be obtained from the glass raw material contained in the melting container, it does not matter if the electromagnetic wave is not directly irradiated onto all of the glass raw material contained in the melting container (even in an embodiment where the electromagnetic wave is directly irradiated onto a part of the glass raw material contained in the melting container). However, embodiments in which the electromagnetic wave is not directly irradiated onto the glass raw material, such as applying the electromagnetic wave to a conductor arranged so as to surround the melting container to heat the conductor by generating heat, are not included herein. Also, the shortest distance (the shortest straight-line distance) from the irradiation source to the glass raw material is not particularly limited as long as a glass melt can be obtained from the glass raw material contained in the melting container.

[0018] In addition, the frequency of the electromagnetic wave directly irradiated onto the glass raw material in this glass melt forming step is more preferably 50 Hz or more and 30 GHz or less because the effects of the present invention are more likely to be exhibited. This lower limit is more preferably 100 Hz or more, still more preferably 1 kHz or more, still more preferably 100 kHz or more, still more preferably 1 MHz or more, still more preferably 100 MHz or more, and still more preferably 1 GHz or more. The upper limit is more preferably 20 GHz or less, still more preferably 10 GHz or less, and still more preferably 5 GHz or less.

[0019] <Preheating Step> In addition to the glass melt formation process described above, the method for manufacturing a glass melt according to the present invention preferably includes a preheating step of preheating at least a part of the glass raw material to a temperature of 300°C or higher and 800°C or lower by an external heat source before the glass raw material is accommodated in the melting vessel or after the glass raw material is accommodated in the melting vessel and before direct irradiation with electromagnetic waves. By performing this preheating step, the preheated glass raw material includes a state that is not solid (a liquefied state and / or a softened state that has not yet reached liquefaction) not in all but in a part thereof. When the glass raw material includes such a state, the conductivity of the glass raw material is further increased, and the formation of the glass melt by direct irradiation with electromagnetic waves in the above-described glass melt formation process can proceed more efficiently.

[0020] And this preheating step is a step of preheating a part or all of the glass raw material before the glass melt formation process to a temperature of 300°C or higher and 800°C or lower by an external heat source. That is, this is a step of preheating all of this glass raw material to a temperature of 300°C or higher and 800°C or lower, or a step of preheating a part of this glass raw material so that its temperature (the temperature of this part of the glass raw material) is 300°C or higher and 800°C or lower.

[0021] In addition, in this preheating step, direct heating such as the direct irradiation with electromagnetic waves described above is not performed, and the glass raw material is preheated by an external heat source. For example, heating by a burner method or an electric heater method is exemplified, and further, a method of applying electromagnetic waves to a conductor to generate heat in the conductor and performing heating with this conductor may also be used. And this preheating step may be performed on the glass raw material before being accommodated in the melting vessel (for example, the one accommodated in another container or the one placed on a conveyor), or may be performed on the glass raw material accommodated in the melting vessel (the one before the glass melt formation process).

[0022] Furthermore, regarding the temperature, the temperature of the glass raw material to be preheated may be set to 300°C or higher and 800°C or lower, for example, it may be set to 350°C or higher and 700°C or lower. Also, since the effects of the present invention are more likely to be exhibited, this preheating step is preferably a step of preheating the above-described glass raw material so that less than 50% by mass, further less than 30% by mass, and further less than 10% by mass of the total amount of the glass raw material is not in a solid state within the above temperature range. And in the glass melt forming step described above, it is more preferable from the viewpoint of heating efficiency and the like to directly irradiate electromagnetic waves onto the glass raw material that has been subjected to predetermined preheating and is not in a solid state at the above-described ratio (glass raw material containing the non-solid state at the above-described ratio).

[0023] <Mixing step> When the method for producing a glass melt according to the present invention includes the above-described preheating step, it is more preferable to further include a mixing step of mixing the glass raw material preheated by the preheating step and the glass raw material not preheated before the glass melt forming step described above.

[0024] This mixing step is a step of mixing the glass raw material preheated by the above-described preheating step (temperature is 300°C or higher and 800°C or lower) and the glass raw material not preheated (glass raw material that has not undergone the above-described preheating step, preferably a glass raw material at 5°C or higher and less than 50°C) so as to be substantially uniform. This mixing may also be performed before being housed in the melting container (outside the melting container), or mixing may be performed inside the melting container.

[0025] The mixing method is not particularly limited, and examples include a method of mixing using a dry mixer or the like as described above. Also, when mixing is performed inside the melting container, the melting container may be vibrated or the like, or a stirring rod or the like may be inserted to perform stirring or the like. And from the viewpoint of ease of mixing and the like, it is preferable that both the glass raw material preheated by the preheating step and the glass raw material not preheated are in a powdery (powder) form.

[0026] Note that the mixing ratio (mass ratio) of the glass raw material preheated by the preliminary heating step and the glass raw material not preheated is not limited, but they may be mixed such that the mass of the preheated glass raw material is equal to or greater than (1 times or more this mass) the mass of the glass raw material not preheated. That is, they may be mixed in equal amounts, or such that the mass of the preheated glass raw material is greater than the mass of the glass raw material not preheated. When using a part of the preheated glass raw material, they may be mixed such that the mass of the preheated part of the glass raw material is equal to or greater than the total mass of the remaining glass raw material and the unpreheated glass raw material to be mixed. The upper limit may be that the mass of the preheated glass raw material is 3 times or less the mass of the glass raw material not preheated, may be 2.5 times or less, or may be 2 times or less. And in the above-described glass melt forming step after this mixing step, it is preferable that the glass raw material directly irradiated with electromagnetic waves contains a non-solid state in the above-described ratio (the non-solid state is in the above-described ratio).

[0027] <Raw material replenishment step> The method for manufacturing a glass melt according to the present invention is more preferably further provided with a raw material replenishment step of mixing the glass melt obtained in the above-described glass melt forming step and a glass raw material not preheated. By performing this raw material replenishment step, at least a part of the replenished and mixed glass raw materials can be melted by the heat of the glass melt obtained in the above-described glass melt formation step, and the heating efficiency in glass melt production can be further enhanced. Here, this raw material replenishment step may be a step of mixing a predetermined glass melt and a glass raw material that has not been preheated without directly irradiating electromagnetic waves (in this case, from the viewpoint of heating efficiency, an embodiment in which heating is not performed in the raw material replenishment step including heating by an external heat source is more preferable), or a step of mixing a predetermined glass melt obtained while directly irradiating electromagnetic waves in parallel with the glass melt formation step and a glass raw material that has not been preheated.

[0028] The glass raw material mixed with the glass melt in this raw material replenishment step may be the glass raw material as described above. However, from the viewpoint of the above effects, this glass raw material needs to be not preheated (not having passed through the above-described preheating step, preferably at a temperature lower than 50°C). And this mixing method is not particularly limited. For example, it may be a method of charging a powdery glass raw material at a temperature lower than 50°C that has not been preheated into the glass melt obtained in the glass melt formation step while stirring the glass melt with a stirring rod or the like.

[0029] In addition, from the viewpoint of heating efficiency and the like, the mixing ratio (mass ratio) of the glass melt and the glass raw material in the raw material replenishment step is more preferably such that the mass of the glass melt exceeds the mass of the glass raw material (more than one-fold the mass of the glass raw material). That is, it is more preferable to mix them so that the mass of the glass melt is greater than the mass of the glass raw material. The upper limit is preferably such that the mass of the glass melt is 10-fold or less, and more preferably 8-fold or less, the mass of the glass raw material.

[0030] Furthermore, in the method for producing a glass melt according to the present invention, it is more preferable to select and adjust the steps depending on whether the glass raw material used contains a phosphorus compound or not. Specifically, when using a glass raw material that does not contain a phosphorus compound, it is more preferable to perform the preheating step described above. That is, before the glass raw material that does not contain a phosphorus compound is accommodated in a melting container having an opening, or after it is accommodated in this melting container (before direct irradiation with electromagnetic waves), at least a part of this glass raw material is preheated by an external heat source so that the temperature becomes 300°C or higher and 800°C or lower. A preheating step, and for this glass raw material preheated by the preheating step and accommodated in the melting container, electromagnetic waves are directly irradiated from the opening of the melting container to melt this glass raw material to obtain a glass melt. It is preferable to adopt a method including a glass melt forming step.

[0031] On the other hand, when using a glass raw material containing a phosphorus compound, it is more preferable to perform the production without performing the preheating step described above. That is, for a phosphorus compound-containing glass raw material that is accommodated in a melting container having an opening and has not been preheated (has not undergone a preheating step of preheating by an external heat source or electromagnetic waves, preferably at a temperature of less than 50°C), electromagnetic waves are directly irradiated from the opening of the melting container to melt this glass raw material to obtain a glass melt. It is preferable to adopt a method including a glass melt forming step.

[0032] <Other processes, etc.> In the method for producing a glass melt according to the present invention, within a range that does not significantly affect the effects of the present invention, any other steps may be further included. For example, a sieving step for separating the particle sizes of the glass raw materials may be provided. As an example of an embodiment of the method for manufacturing a glass melt according to the present invention, there are a method of directly processing glass raw materials by a predetermined glass melt forming step, a method of processing glass raw materials by a predetermined preheating step and then processing them by a predetermined glass melt forming step, a method of processing glass raw materials by a predetermined preheating step, further mixing the glass raw materials not preheated in a predetermined mixing step with the glass raw materials processed by this preheating step, and then processing them by a predetermined glass melt forming step, and a method of performing a raw material replenishment step of mixing the glass melt obtained in a predetermined glass melt forming step with glass raw materials not preheated. FIG. 1 shows a flow chart of each manufacturing step of these methods.

[0033] The glass melt produced by the method for manufacturing a glass melt according to the present invention as described above may be used for cullet production, or may be cooled and molded into glass products, or may be vitrified and used for cullet production, and further secondary melting may be performed.

[0034] Furthermore, using the glass melt produced by the method for manufacturing a glass melt according to the present invention, it is also possible to manufacture glass-ceramics. Specifically, after the glass melt forming step as described above and solidifying the glass melt obtained in this glass melt forming step to obtain a glass solid (a solid in an amorphous state), electromagnetic waves are directly irradiated onto this glass solid to heat and crystallize the glass solid (partially crystallize it) to obtain a glass-ceramic containing a crystal phase and an amorphous phase. A glass-ceramic can be manufactured by a method comprising a crystallization glass forming step. The direct irradiation of electromagnetic waves onto this glass solid may be the same as the direct irradiation of electromagnetic waves onto the glass raw materials described above, except that it is not necessary to use a melting container (it is not necessary to irradiate electromagnetic waves from the opening of the melting container).

[0035] Next, each member and the like of the glass melt manufacturing apparatus of the present invention will be described in detail. Incidentally, the glass melt production apparatus of the present invention can also be applied to either primary melting mainly for heating and melting batch raw materials or secondary melting mainly for reheating and melting cullets, similar to the method for producing a glass melt according to the present invention described above. However, it is more preferably applied particularly to primary melting or both primary melting and secondary melting.

[0036] <Glass melt forming section> The glass melt production apparatus of the present invention includes a melting container having an opening and an electromagnetic wave irradiator, and is a unit that directly irradiates electromagnetic waves from the opening of the melting container to the glass raw material accommodated in the melting container by the electromagnetic wave irradiator, melts the glass raw material, and obtains a glass melt, and includes a glass melt forming section.

[0037] This glass melt forming section has at least a melting container having an opening and an electromagnetic wave irradiator. And this electromagnetic wave irradiator is arranged so that electromagnetic waves can be directly irradiated from the opening of the melting container to the internal glass raw material. Here, the melting container and the like may be the same as described above. Also, this "direct irradiation" has the same meaning as described above. And within a range that does not significantly affect the effects of the present invention, other members (for example, a temperature measuring section for measuring the temperature of the glass raw material or the glass melt) may be provided together.

[0038] Incidentally, the frequency of the electromagnetic waves irradiated from the electromagnetic wave irradiator of this glass melt forming section is also more preferably 50 Hz or more and 30 GHz or less, because the effects of the present invention are more likely to be exerted as described above. And the lower limit and the upper limit may be the same as described above.

[0039] <Preheating section> The glass melt production apparatus of the present invention preferably includes, in addition to the above-described glass melt forming section, a preheating section that preheats at least a part of the glass raw material by an external heat source so that the temperature becomes 300°C or more and 800°C or less before the glass raw material is accommodated in the melting container or after the glass raw material is accommodated in the melting container and before direct irradiation of electromagnetic waves is performed.

[0040] In this preheating section, before the treatment in the glass melt forming section, part or all of the glass raw material is preheated by an external heat source so that the temperature becomes 300°C or higher and 800°C or lower (for example, 350°C or higher and 700°C or lower). Examples of this external heat source include a burner, an electric heater, and a conductor capable of applying electromagnetic waves. Note that this preheating may be performed in the above-described melting container. That is, this preheating section and the above-described glass melt forming section may be integrated (a unit capable of performing both preheating and glass melt forming).

[0041] Furthermore, since the effects of the present invention are more likely to be exhibited, this preheating section is preferably a unit that preheats the above-described glass raw material so that less than 50% by mass, further less than 30% by mass, and further less than 10% by mass of the total amount of the glass raw material is not in a solid state within the above temperature range.

[0042] <Mixing section> When the glass melt production apparatus of the present invention includes the above-described preheating section, it is more preferable to include a mixing section that mixes the glass raw material preheated by the preheating section and the glass raw material that has not been preheated before direct irradiation with electromagnetic waves in the glass melt forming section.

[0043] This mixing section is a unit that mixes the glass raw material preheated in the above-described preheating section (temperature is 300°C or higher and 800°C or lower) and the glass raw material that has not been preheated (the glass raw material that has not undergone preheating by an external heat source or electromagnetic waves, preferably the glass raw material at 5°C or higher and less than 50°C) so as to be substantially uniform. This mixing may also be performed before being housed in the melting container (outside the melting container), or mixing may be performed inside the melting container. That is, this mixing section and the above-described glass melt forming section and / or preheating section may be integrated.

[0044] In addition, this mixing section is provided with a member for performing mixing. Examples include a container capable of vibration or rotation, and a container equipped with a stirring rod, stirring blades, etc. Note that the mixing ratio (mass ratio) and properties of the glass raw material preheated in the preliminary heating section and the glass raw material not preheated in this mixing section may be the same as described above. Furthermore, it is more preferable that this mixing section is a unit that enables the proportion of the non-solid state in the glass raw material after mixing (the glass raw material before direct irradiation with electromagnetic waves) to be within the range described above.

[0045] <Raw material replenishment section> It is more preferable that the glass melt production apparatus according to the present invention further includes a raw material replenishment section for mixing the glass melt obtained in the glass melt forming section described above and the glass raw material not preheated.

[0046] This raw material replenishment section is a unit that mixes the glass melt obtained in the glass melt forming section described above and the glass raw material not preheated (not having undergone preheating in the preheating section described above, preferably at a temperature below 50°C) and melts the replenished and mixed glass raw material. This may be a unit that transfers a predetermined glass melt from a melting container to another container and then performs the operation without direct irradiation with electromagnetic waves, or a unit that performs the operation while directly irradiating with electromagnetic waves or without direct irradiation with electromagnetic waves inside the melting container. That is, this raw material replenishment section and the glass melt forming section (and further the preheating section) described above may be integrated.

[0047] In addition, it is preferable that this raw material replenishment section is provided with members for stirring the glass melt and mixing (adding) the glass raw material (such as a container capable of vibration or rotation, a stirring rod, stirring blades, a pipe for supplying the glass raw material, etc.). Note that this raw material replenishment section may be a unit that mixes a predetermined glass melt and a glass raw material without performing heating including heating by an external heat source, for example, a unit that does not include a member for performing heating including heating by an external heat source (a unit separate from the glass melt forming section). And the mixing ratio (mass ratio) of the glass raw material with the glass melt in this raw material replenishing section and the properties of the glass raw material may be the same as described above.

[0048] <Other units, etc.> Furthermore, the glass melt manufacturing apparatus of the present invention may also include any unit other than the above as long as it does not significantly affect the effects of the present invention. For example, it may be provided with a classification section which is a unit for classifying the particle size of the glass raw material.

[0049] The embodiments described above are merely examples for facilitating the understanding of the present invention and do not limit the present invention. That is, the steps and the like described above can be changed and improved without departing from the spirit of the present invention, and it goes without saying that the present invention includes equivalents thereof.

[0050] Hereinafter, examples of the present invention will be described, but the present invention is not limited to the following examples, and various modifications are possible within the technical idea of the present invention.

Examples

[0051] The glass raw material was processed by each step, and it was determined whether it had become a glass melt. Specifically, it was carried out as follows.

[0052] As the glass raw material, Samples 1 to 5 were SiO 2 , Na 2 CO 3 , and K 2 CO 3Those prepared by mixing a predetermined amount were used. For Sample 1, this glass raw material was placed in a platinum crucible and heated by an external heat source (heating by a burner method) to a temperature of 300°C or higher and 800°C or lower. For Sample 2, this glass raw material was placed in a platinum crucible and preheated by an external heat source (heating by a burner method) to a temperature of 300°C or higher and 800°C or lower so that a part of it (less than 50% by mass) was in a non-solid state (preheating step). Then, electromagnetic waves of 2.45 GHz were directly irradiated onto the preheated glass raw material from the opening of the platinum crucible (glass melt formation step). Further, for Sample 3, this glass raw material was placed in a platinum crucible, and without heating by an external heat source, electromagnetic waves of 2.45 GHz were directly irradiated onto this glass raw material (less than 50°C) from the opening of the platinum crucible (glass melt formation step).

[0053] For Sample 4, this glass raw material was placed in a platinum crucible and preheated by an external heat source (heating by a burner method) to a temperature of 300°C or higher and 800°C or lower so that a part of it (less than 50% by mass) was in a non-solid state (preheating step). Then, an equal amount of a glass raw material having the same composition and not preheated was added and mixed (mixing step). Electromagnetic waves of 2.45 GHz were directly irradiated onto this mixed glass raw material from the opening of the platinum crucible (glass melt formation step). Further, for Sample 5, this glass raw material was placed in a platinum crucible and heated by an external heat source (heating by a burner method) to a temperature of 300°C or higher and 800°C or lower so that a part of it (less than 50% by mass) was in a non-solid state. Then, an equal amount of a glass raw material having the same composition and less than 50°C that was not preheated was added and mixed.

[0054] On the other hand, for Sample 6, as the glass raw material, SiO 2 , Na 2 CO 3 , K 2 CO 3 , and H 3 PO 4Using the one prepared by blending a predetermined amount, this glass raw material was placed in a platinum crucible and irradiated directly with electromagnetic waves of 2.45 GHz from the opening of the platinum crucible to the glass raw material (less than 50 °C) without heating by an external heat source (glass melt forming step).

[0055] And for these Samples 1 to 6, it was visually determined based on the following criteria whether the whole had become a glass melt. ◎: The whole became a melt more rapidly. 〇: The whole became a melt. △: The whole became a melt, but it took a little time to become a melt. ×: Part or all did not become a melt.

[0056] The processing steps and determination results of these samples are summarized in Table 1 below. The steps marked with black circles are the steps that were carried out. From these results, it was shown that by performing a predetermined glass melt forming step, a glass melt in which the whole became a melt could be obtained from the glass raw material (Samples 2 to 4, 6). In particular, by combining a predetermined preheating step and a predetermined glass melt forming step, or by combining a predetermined preheating step, a predetermined mixing step, and a predetermined glass melt forming step, it was shown that a glass melt could be obtained more efficiently from the glass raw material (Samples 2, 4). Also, when using a glass raw material containing a phosphorus compound, it was shown that a glass melt could be rapidly obtained by only carrying out a predetermined glass melt forming step (Sample 6). Furthermore, although not shown in Table 1 below, when a glass melt was produced by adjusting the amount so that the total amount after the mixing step was the same as the total amount at the time of the preheating step of Sample 2 (that is, the total amount at the time of the preheating step of Sample 4) in the same manner as Sample 4, the determination result was equivalent to that of Sample 2.

[0057]

Table 1

Claims

1. A method for producing a molten glass from a glass raw material, comprising the steps of: a glass melt forming step of directly irradiating the glass frit contained in a melting vessel having an opening with an electromagnetic wave through the opening of the melting vessel to melt the glass frit and obtain a glass melt; A method for producing a glass melt.

2. 2. The method for producing a molten glass according to claim 1, further comprising a preheating step of preheating at least a part of the glass frit to a temperature of 300° C. or more and 800° C. or less by an external heat source before the glass frit is placed in the melting vessel, or after the glass frit is placed in the melting vessel and before the direct irradiation of the electromagnetic waves.

3. The method for producing a glass melt according to claim 2, further comprising, before the glass melt forming step, a mixing step of mixing the glass frit preheated in the preheating step with the glass frit that has not been preheated.

4. The method for producing a molten glass according to claim 1 , further comprising a raw material replenishing step of mixing the molten glass obtained in the molten glass forming step with a glass raw material that has not been preheated.

5. A method for producing a glass melt from a glass raw material not containing a phosphorus compound, comprising the steps of: a preheating step of preheating at least a part of the glass frit to a temperature of 300° C. or more and 800° C. or less by an external heat source before or after the glass frit is placed in a melting vessel having an opening; and a glass melt forming step of directly irradiating the glass frit preheated in the preheating step and contained in the melting vessel with electromagnetic waves from the opening of the melting vessel to melt the glass frit and obtain a glass melt. A method for producing a glass melt.

6. A method for producing a molten glass from a glass raw material containing a phosphorus compound, comprising the steps of: a glass melt forming step of directly irradiating the glass frit, which is contained in a melting vessel having an opening and has not been preheated, with an electromagnetic wave through the opening of the melting vessel to melt the glass frit and obtain a molten glass. A method for producing a glass melt.

7. The method for producing a glass melt according to any one of claims 1 to 6, wherein the frequency of the electromagnetic waves in the glass melt forming step is 50 Hz or more and 30 GHz or less.

8. The method for producing a molten glass according to any one of claims 1 to 6, wherein the glass raw material is a glass raw material containing neither Se nor Te.

9. An apparatus for producing a molten glass from a glass raw material, comprising: a glass melt forming section including a melting vessel having an opening and an electromagnetic wave applicator, the electromagnetic wave applicator directly irradiating the glass frit contained in the melting vessel with electromagnetic waves from the opening of the melting vessel to melt the glass frit and obtain a molten glass; Glass melt manufacturing equipment.

10. 10. The glass melt producing apparatus according to claim 9, further comprising a preheating unit for preheating at least a part of the glass frit to a temperature of 300° C. or more and 800° C. or less by an external heat source before the glass frit is placed in the melting vessel, or after the glass frit is placed in the melting vessel and before the electromagnetic waves are directly irradiated.

11. The glass melt producing apparatus according to claim 10, further comprising a mixing section for mixing the glass frit preheated by the preheating section and the glass frit not preheated before the direct irradiation of the electromagnetic waves in the glass melt forming section.

12. 10. The apparatus for producing a molten glass according to claim 9, further comprising a raw material replenishing section for mixing the molten glass obtained in the molten glass forming section with a glass raw material that has not been preheated.

13. 13. The glass melt manufacturing apparatus according to claim 9, wherein the frequency of the electromagnetic waves irradiated by the electromagnetic wave applicator in the glass melt forming section is 50 Hz or more and 30 GHz or less.

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