TW202016031A - Method for manufacturing glass article - Google Patents

Abstract

A manufacturing method which comprises: a continuous formation process for, while electrically heating a molten glass 2 pooled in a furnace 1, melting an alkali-free glass starting material 4 continuously fed thereto to thereby continuously form fresh molten glass 2 and, at the same time, flowing out the molten glass 2 from the furnace 1 through an outflow port 5; and a set-up process for setting up the furnace 1 until the aforesaid process becomes executable, wherein the set-up process involves a first temperature rising step for rising the temperature in the furnace 1 from room temperature using an air combustion burner 7 and a second temperature rising step for, after starting the first temperature rising step, rising the temperature in the furnace 1 using an oxygen combustion burner 8.

Description

Glass article manufacturing method

The present invention relates to a method of manufacturing a glass article. The method of manufacturing a glass article includes: a step of continuously generating molten glass as a raw material of a glass article using a glass melting furnace; and starting the glass melting furnace to a state where the step can be performed A step of.

As is well known, glass articles represented by glass plates, glass tubes, glass fibers, and the like are manufactured by forming molten glass produced by melting glass raw materials into a predetermined shape. Here, Patent Document 1 discloses an example of a method of continuously generating molten glass using a glass melting furnace.

In the method disclosed in this document, while the molten glass stored in the glass melting furnace is electrically heated by an electrode, the glass raw material continuously supplied to the molten glass is melted to continuously generate new molten glass, and the molten Glass flows out of the furnace from the outflow of the glass melting furnace. [Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2003-183031

[Problems to be solved by the invention] In addition, when the glass melting furnace is operated, it is necessary to start the furnace to a state where molten glass can be continuously produced. As an example of the form of the start-up furnace, an form of using an air burner in which a gas fuel such as natural gas is mixed with air and burned can be cited.

In this form, first, the temperature in the glass melting furnace is raised from normal temperature by the firepower of the air burner. Then, when the temperature in the furnace rises to a temperature at which the glass raw material can be melted (hereinafter, expressed as a meltable temperature), the supply of glass raw material into the furnace is started. Along with this, the glass raw material is melted and the molten glass is stored in the furnace. Finally, the molten glass stored in the furnace is electrically heated by the electrode.

However, when the glass melting furnace of the above-mentioned form is started, when the molten glass to be produced in the furnace is glass with a high melting temperature, for example, when it is alkali-free glass, there are the following problems.

That is, in this case, of course, it is necessary to supply glass raw materials for alkali-free glass (hereinafter, expressed as alkali-free glass raw materials) into the furnace. Furthermore, this alkali-free glass raw material has a property of having a higher melting temperature than other glass raw materials. Due to this situation, there is a disadvantage that the firepower of the air burner cannot stably raise the temperature in the furnace to the melting temperature of the alkali-free glass raw material, and the alkali-free glass raw material cannot be sufficiently melted.

Therefore, as a countermeasure against the above-mentioned problems, it is conceivable to use an oxygen burner (burner that mixes gaseous fuel with oxygen and burns) with higher thermal power instead of the air burner. When this oxygen burner is used, the temperature in the furnace can be stably raised to the melting temperature of the alkali-free glass raw material. However, on the other hand, when the temperature in the furnace is increased from normal temperature, the furnace wall is locally heated, and the refractory (brick) constituting the furnace wall may be damaged due to thermal stress.

As such, the current situation is that the case of using an oxygen burner instead of an air burner cannot be an effective countermeasure against the above-mentioned disadvantages, and a new countermeasure for appropriately starting the glass melting furnace needs to be taken. The technical problem of the present invention proposed in view of the above circumstances is that when a glass melting furnace is used to continuously produce molten glass composed of glass having a high melting temperature when a glass article is manufactured, the furnace can be properly started. [Means to solve the problem]

The present invention for solving the above-mentioned problems is a method for manufacturing a glass article, including a continuous production step of continuously supplying molten glass while energizing and heating molten glass stored in a glass melting furnace whose furnace wall is a refractory The glass raw material on the glass is melted to continuously generate new molten glass, and the molten glass flows out of the outflow port of the glass melting furnace to the outside of the furnace; and the starting step is to start the glass melting furnace to a state where the continuous generating step can be performed, said The method of manufacturing a glass article is characterized in that the starting step includes: a first temperature increasing step, which raises the temperature in the glass melting furnace from an ordinary temperature by an air burner; and a second temperature increasing step, after the start of the first temperature increasing step, The oxygen burner raises the temperature in the glass melting furnace.

In the start-up step in this method, after the first temperature-increasing step for raising the temperature in the glass melting furnace from the normal temperature by the air burner, a second temperature-increasing step for raising the temperature in the furnace by the oxygen burner is performed . With this, the refractory constituting the furnace wall can be protected from damage due to thermal stress, and the temperature in the furnace can be stably raised to the melting temperature of the glass raw material. In addition, the reason why the refractory can be protected from damage is that, by using an oxygen burner to heat the inside of the furnace pre-heated by the air burner, local heating of the furnace wall can be avoided. According to this, according to this method, when a glass melting furnace is used to continuously produce a molten glass composed of glass having a high melting temperature when manufacturing a glass article, an appropriate start of the furnace can be achieved.

In the above method, the glass raw material is preferably an alkali-free glass raw material.

Since the melting temperature of the alkali-free glass raw material is high, the effect becomes remarkable.

In the method, it is preferable that the starting step further includes: a raw material supply starting step to start supplying glass raw materials into the glass melting furnace; and an energized heating start step to melt the supplied glass raw material to start energized heating of the stored molten glass .

Since the glass raw material supplied after the raw material supply start step can be surely melted and stored in the furnace, the energization heating start step can be reliably performed, and the stored molten glass can be surely started to be energized heating. With this, the furnace can be started more appropriately.

In the above method, it is preferable that after the start of the second temperature raising step, the resistivity of the molten glass stored in the glass melting furnace is lower than the resistivity of the refractory, and then the energization heating start step is performed.

In this way, the possibility of damaging the refractory can be accurately ruled out by passing an electric current through the refractory instead of the molten glass that is the object of energized heating.

In the above method, the refractory preferably includes a refractory having a resistivity of 800 Ω·cm or more at 1400°C.

In this way, by containing a refractory material with a sufficiently high electrical resistivity, it is easier to circulate current through the molten glass than the refractory material (furnace wall) after the start step of energized heating, thus eliminating the possibility of refractory damage The aspect becomes favorable.

In the above method, the electrical resistivity of the molten glass is preferably less than 800 Ω·cm at 1400°C.

In this way, after the start of the energization heating, the electrical resistivity of the molten glass is surely reduced compared to the electrical resistivity of the refractory (furnace wall), and thus it is more advantageous in eliminating the possibility of damage to the refractory (furnace wall).

In the above method, it is preferable to perform the raw material supply start step after the temperature in the glass melting furnace rises to a temperature (meltable temperature) at which the glass raw material can be melted after the second temperature raising step is started.

In this way, since the glass raw material supplied after the raw material supply start step starts melting immediately after the supply, it is possible to accurately prevent the components contained in the glass raw material from volatilizing and disappearing before the raw material is melted.

In the above method, it is preferable to stop the air burner after the second temperature increase step is started.

In this way, for an air burner that has a significantly lower firepower than an oxygen burner and has a low contribution to increasing the temperature in the furnace, by stopping it after the start of the second heating step, the manufacturing cost of glass articles can be avoided Improperly increased.

In the above method, in the continuous generation step, it is preferable to heat the molten glass only by energized heating.

In this way, the environment in the glass melting furnace is dry compared with the case of burning with a combined burner. Therefore, the moisture in the environment can be prevented from dissolving into the molten glass, and the β-OH value of the resulting glass article can be reduced. Thereby, the compaction at the time of heating the obtained glass article can be reduced, and the glass article suitable for the glass substrate for displays can be obtained. [Effect of invention]

According to the present invention, when manufacturing a glass article, when a glass melting furnace is used to continuously generate molten glass composed of glass having a high melting temperature, the furnace can be properly started.

Hereinafter, a method of manufacturing a glass article according to an embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show a state where a continuous generation step is performed in a glass melting furnace 1 (hereinafter simply referred to as furnace 1 ).

In the continuous production step, while the temperature in the furnace 1 (molten glass) is maintained at the operating temperature (for example, 1450°C to 1550°C), the molten glass 2 stored in the furnace 1 is electrically heated by the electrode 3 While the alkali-free glass raw materials 4 continuously supplied to the surface 2a of the molten glass 2 are sequentially melted, new molten glass 2 is continuously produced, and the molten glass 2 flows out of the furnace 1 from the outlet 5. In this continuous generation step, the molten glass 2 is heated only by the energization heating of the electrode 3.

The molten glass 2 made of alkali-free glass generated in the continuous production step is sent to the downstream step including the forming step and the like, and the molten glass 2 is formed in the downstream step to form a glass article (such as a glass plate, Glass tubes, fiberglass, etc.).

Here, the “alkali-free glass” refers to glass that does not substantially contain an alkali component (alkali metal oxide), and specifically refers to glass having a weight ratio of the alkali component of 3000 ppm or less. Furthermore, the weight of the alkali component is preferably 1000 ppm or less, more preferably 500 ppm or less, and most preferably 300 ppm or less. In this embodiment, the specific resistance of the molten glass 2 made of alkali-free glass is less than 800 Ω·cm at 1400°C.

The furnace 1 used in this embodiment has a rectangular cross-sectional shape in plan view. This furnace 1 has a front wall 1a located at the upstream end in the flow direction T of the alkali-free glass raw material 4 in the furnace 1, a rear wall 1b located at the downstream end, a pair of side walls 1c, 1d, a top wall 1e, and a bottom wall 1f. In the furnace wall 1a to the furnace wall 1f, the bottom wall 1f where the electrode 3 is arranged contains a high-resistance refractory (such as high-zirconia electroformed refractory brick or dense zircon calcination at 1400°C with a resistivity of 800 Ω·cm or more tile). The bottom wall 1f of this embodiment further contains a high-corrosion-resistant refractory excellent in corrosion resistance (for example, a zirconia-based electroformed refractory brick). The high corrosion resistance refractory is arranged so as to surround the electrode 3, and the high resistance refractory is arranged between the high corrosion resistance refractory. The high-resistance refractory material preferably has a resistivity at 1400°C of 1000 Ω·cm or more. On the other hand, from the viewpoint of preventing the increase in cost required for the refractory, it is preferable that the high-resistance refractory has a specific resistance at 1400° C. of 50,000 Ω·cm or less. Furthermore, the high-resistance refractory material may be arranged so as to prevent current from flowing through the entire bottom wall 1f, and is not limited to the arrangement of this embodiment.

A plurality of (three in this embodiment) spiral feeders 6 for supplying the alkali-free glass raw material 4 into the furnace 1 are arranged in parallel on the front wall 1 a. Each screw feeder 6 is inserted into the opening 1aa formed in the front wall 1a without a gap. Furthermore, tin oxide is added as a clarifier to the alkali-free glass raw material 4 supplied from the screw feeder 6.

Here, in this embodiment, the screw feeder 6 is used for the supply of the alkali-free glass raw material 4, but a feeder other than the screw feeder 6 may be used. As an example of the feeder, a vibrating feeder, a pusher, a blanket feeder, etc. can also be used. From the viewpoint of improving the airtightness in the furnace 1, it is preferable to use a screw feeder 6 or a vibrating feeder. In addition, in this embodiment, a plurality of screw feeders 6 are used, but the number of screw feeders 6 may be only one.

An outlet 5 for allowing molten glass 2 to flow out is arranged on the rear wall 1b.

On the side wall 1c and the side wall 1d, a burner pair 9 composed of a pair of an air burner 7 and an oxygen burner 8 is arranged. In this embodiment, three pairs of burner pairs 9 are arranged on the side wall 1c. , Two pairs of burners 9 are arranged on the side wall 1d. Furthermore, in this embodiment, the air burner 7 and the oxygen burner 8 are arranged in pairs, but the number of the air burner 7 and the oxygen burner 8 may be different. In addition, the air burner 7 and the oxygen burner 8 may be disposed on the top wall 1e. In the execution of the continuous generation step of the present embodiment, in each of the five pairs of burner pairs 9 in total, both the air burner 7 and the oxygen burner 8 are in a stopped state, but in the execution of the continuous generation step In the meantime, the air burner 7 and/or the oxygen burner 8 may be operated.

The air burner 7 is a burner that mixes gas fuel such as natural gas with air and burns it. On the other hand, the oxygen burner 8 is a burner that mixes and burns gaseous fuel with oxygen.

As shown by the two-dot chain line in FIG. 2, the two burners 7 and 8 can respectively inject flames 7 a and 8 a from the side wall 1 c (side wall 1 d) side to the opposite side wall 1 d (side wall 1 c) side. Furthermore, the thermal power of the oxygen burner 8 is greater than the thermal power of the air burner 7. On the other hand, the flame 7a injected by the air burner 7 is wider than the flame 8a injected by the oxygen burner 8 in plan view. Furthermore, in the present embodiment, the air burner 7 can be detached from the side wall 1c (side wall 1d) in a state where the operation is stopped. The oxygen burner 8 can also be detached from the side wall 1c (side wall 1d) in a state where the operation is stopped.

The electrode 3 arranged on the bottom wall 1f is formed in a rod shape. The electrode 3 can be moved into and out of the furnace 1 from the bottom wall 1f (the position where the electrode 3 is located in FIG. 1) and the retreat position from the furnace 1 (where the electrode 3 is located in FIG. 3 mentioned later) Position). The electrode 3 is made of molybdenum, for example.

In the execution of the continuous generation step, the molten glass 2 is heated by the electrode 3 located in the entrance and exit position and in a state of being immersed in the molten glass 2 in the furnace 1. By adjusting the voltage applied to the electrode 3, the energy (heat energy given to the molten glass 2) generated by the electrode 3 can be adjusted. Further, as the electrode 3 heats the molten glass 2, the alkali-free glass raw material 4 on the surface 2 a of the molten glass 2 is indirectly heated and melted. With this, new molten glass 2 is sequentially produced.

Here, in the present embodiment, the molten glass 2 is heated by the rod-shaped electrode 3, but in addition to the rod-shaped electrode 3, or instead of the rod-shaped electrode 3, it may be arranged by a pair of side walls The plate-shaped electrode or the bulk-shaped electrode on 1c and 1d heats the molten glass 2.

In this embodiment, when the furnace 1 is started to a state where the continuous generation step can be executed, the following start-up step is performed.

In the startup step, the first temperature increase step (Figure 3), the second temperature increase step (Figure 4), the raw material supply start step (Figure 5), and the energization heating start step (Figure 7), where the first temperature increase step is The step of raising the temperature in the furnace 1 from the normal temperature (especially the temperature without cooling or heating, for example, 20±15°C) by the air burner 7, and the second heating step is to make the temperature in the furnace 1 by the oxygen burner 8 The temperature increase step, the raw material supply start step is a step of starting to supply the alkali-free glass raw material 4 into the furnace 1, and the energization heating start step is a step of melting the alkali-free glass raw material 4 to start the energization heating of the stored molten glass 2.

First, as preparations for performing the start-up step, before the first temperature-raising step is started, as shown in FIG. 3, the electrode 3 is positioned at the retreat position, and then the first glass plate 10 placed on the bottom wall 1f of the furnace 1 is used Cover the electrode 3 above. In this way, the electrode 3 is protected by the first glass plate 10. The state in which the electrode 3 is covered by the first glass plate 10 continues until the first glass plate 10 melts as the temperature in the furnace 1 rises. This prevents the gas in the furnace 1 from contacting the electrode 3 and avoids oxidation of the electrode 3 as much as possible. Furthermore, the space formed between the first glass plate 10 and the electrode 3 is filled with a plurality of pieces of glass (not shown) formed in a block shape.

Here, in the present embodiment, when the electrode 3 is separated from the furnace 1, the first glass plate 10 covers the upper side of the electrode 3, but it is not limited thereto. Instead of the first glass plate 10, for example, the upper part of the electrode 3 may be covered with glass dust. The first glass plate 10 and the glass chips preferably use glass plates and glass chips containing alkali-free glass.

Furthermore, before the start of the first temperature increase step, the outflow port 5 is covered with the second glass plate 11. In this way, the outlet 5 is separated from the furnace 1 by the second glass plate 11. The state where the outlet 5 is separated from the furnace 1 continues until the second glass plate 11 melts as the temperature in the furnace 1 rises. As a result, the flow of gas such as oxygen is prevented between the furnace 1 and the outflow port 5, and the oxidation of platinum contained in the outflow port 5 is avoided as much as possible. The second glass plate 11 is preferably a glass plate containing alkali-free glass.

Here, in the present embodiment, before the start of the first temperature raising step, the first glass plate 10 is used to cover the electrode 3 and the second glass plate 11 is used to cover the outlet 5. These operations are carried out at the beginning of a temperature increase step.

As described above, after the preparation for performing the start-up step is completed, then, as shown in FIG. 3, the flame 7a is injected by operating the air burner 7 to start the first temperature-raising step. Furthermore, in this embodiment, at the start of the first temperature raising step, the supply of the alkali-free glass raw material 4 into the furnace 1 is not started, except for the first glass plate 10 and the second glass plate 11, it becomes the furnace 1 The molten glass 2 and the alkali-free glass raw material 4 are not present.

After the start of the first temperature raising step, when the temperature in the furnace 1 (the ambient temperature of the top wall 1e) rises to any temperature within the range of 700°C to 900°C, the switching from the first temperature raising step to the second temperature raising step is performed . For example, the operation of the air burner 7 is stopped in sequence, and the operation of the oxygen burner 8 is started in sequence. The start of the first operation of the oxygen burner 8 is the start of the second temperature increase step.

After switching from the first heating step to the second heating step, when the temperature in the furnace 1 rises to a temperature at which the alkali-free glass raw material 4 can be melted (hereinafter, expressed as a melting temperature), as shown in FIG. 5, The screw feeder 6 is operated to start supplying the alkali-free glass raw material 4 into the furnace 1, and the raw material supply start step is performed. Part or all of the alkali-free glass raw material 4 may be glass chips.

In addition, the raw material supply start step may be performed simultaneously with the end of the switching from the first temperature increase step to the second temperature increase step as long as the temperature in the furnace 1 rises to the melting temperature. On the other hand, the raw material supply start step may be performed at any time before the temperature in the furnace 1 rises to the melting temperature. However, from the viewpoint of avoiding the possibility that the components contained in the alkali-free glass raw material 4 volatilize and disappear before the raw material 4 is melted, it is preferable to start the raw material supply after the temperature in the furnace 1 rises to the melting temperature step.

After the raw material supply start step, as shown in FIG. 6, the alkali-free glass raw materials 4 supplied into the furnace 1 are sequentially melted, and the molten glass 2 is stored in the furnace 1. Thereby, the height position of the surface 2a of the molten glass 2 in the furnace 1 gradually rises. Furthermore, as indicated by the two-dot chain line in FIG. 6, the first glass plate 10 separating the furnace 3 from the electrode 3 and the second glass plate 11 separating the furnace 1 from the outflow port 5 follow the furnace The temperature in 1 rises and melts in sequence.

Moreover, after the height position of the surface 2a of the molten glass 2 reaches a predetermined reference position, and as the temperature in the furnace 1 rises, the resistivity of the molten glass 2 is lower than the refractory constituting each of the furnace walls 1a to 1f After the resistivity of the object, as shown in FIG. 7, the electrode 3 is moved from the retreat position to the entry/exit position. Then, by applying a voltage to the electrode 3, an electric heating start step is performed. The temperature in the furnace 1 (melted glass) at this time is, for example, in the range of 1300°C to 1600°C. In addition, the "resistivity of molten glass is lower than the resistivity of a refractory" means the state where the resistivity of molten glass at the furnace temperature is lower than the resistivity of the refractory at the furnace temperature.

Then, as shown in FIG. 8, when the height position of the surface 2a of the molten glass 2 reaches the position when the continuous generation step is performed, and the temperature in the furnace 1 becomes substantially uniform at the operating temperature, in order to maintain the temperature in the furnace 1 To stop the operation of the oxygen burner 8 in sequence. When all the oxygen burners 8 are stopped, the start-up step ends. Then, the continuous generation step is started in the furnace 1.

Hereinafter, the main operation and effect of the method of manufacturing a glass article according to the embodiment of the present invention will be described.

In the manufacturing method of the glass article, in the start-up step, after the first temperature-increasing step in which the temperature in the furnace 1 is raised from the normal temperature by the air burner 7 is started, the operation in the furnace 1 by the oxygen burner 8 is performed. The second temperature rising step of temperature rise. With this, the refractory materials constituting the furnace walls 1a to 1f can be protected from damage caused by thermal stress, and the temperature in the furnace 1 can be stably raised to the melting temperature of the alkali-free glass raw material 4. With the above-described effect, the alkali-free glass raw material 4 supplied after the raw material supply start step can be reliably melted and stored in the furnace 1, so that the energization heating start step can also be surely performed. As a result, when the glass article is manufactured, when the molten glass 2 composed of alkali-free glass is continuously produced using the furnace 1, the furnace 1 can be properly started.

In addition, the present invention is not limited to the structure of the above-mentioned embodiment, nor is it limited to the above-mentioned effect. The present invention can be variously modified without departing from the gist of the present invention.

In the above embodiment, the glass raw material is an alkali-free glass raw material, but other glass raw materials with a high melting temperature can also be used. For example, the melting temperature of the glass raw material may be above 900°C, preferably above 1000°C, and more preferably above 1100°C. As the glass raw material, for example, glass raw material of aluminosilicate glass or glass raw material of soda lime glass can be used.

In the above embodiment, the specific resistance of the molten glass is less than 800 Ω·cm at 1400°C, but it is not limited thereto. The resistivity of the molten glass at 1400°C may be, for example, 2000 Ω·cm or less, and preferably less than 800 Ω·cm.

1: glass melting furnace 1a: front wall 1aa: opening 1b: rear wall 1c, 1d: side wall 1e: top wall 1f: bottom wall 2: molten glass 2a: Surface of molten glass 3: electrode 4: Non-alkali glass raw materials 5: Outflow 6: screw feeder 7: Air burner 7a, 8a: flame 8: Oxygen burner 9: burner pair 10: The first glass plate 11: Second glass plate T: flow direction

FIG. 1 is a longitudinal cross-sectional view showing a continuous generation step in a method of manufacturing a glass article according to an embodiment of the present invention. 2 is a cross-sectional plan view showing a continuous generation step in the method of manufacturing a glass article according to an embodiment of the present invention. 3 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to an embodiment of the present invention. 4 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to an embodiment of the present invention. 5 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to an embodiment of the present invention. 6 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to the embodiment of the present invention. 7 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to an embodiment of the present invention. 8 is a longitudinal cross-sectional view showing a start-up step in the method of manufacturing a glass article according to an embodiment of the present invention.

1: glass melting furnace

1a: front wall

1aa: opening

1b: rear wall

1e: top wall

1f: bottom wall

3: electrode

5: Outflow

6: screw feeder

8a: flame

10: The first glass plate

11: Second glass plate

Claims (9)

A method for manufacturing glass articles, comprising: a continuous generation step of melting the glass raw materials continuously supplied to the molten glass while continuously heating the molten glass stored in a glass melting furnace whose furnace wall is a refractory glass melting furnace to continuously produce new Molten glass, and the molten glass flows out of the glass melting furnace out of the furnace; and a starting step, the glass melting furnace is started to a state where the continuous generation step can be performed, the manufacture of the glass article The method is characterized by, The start-up step includes: a first heating step, which raises the temperature in the glass melting furnace from normal temperature by an air burner; and a second heating step, which uses an oxygen burner after the start of the first heating step The temperature in the glass melting furnace is increased. The method for manufacturing a glass article as described in item 1 of the patent application range, wherein the glass raw material is an alkali-free glass raw material. The method for manufacturing a glass article according to item 1 or 2 of the patent application scope, wherein the starting step further includes: a raw material supply starting step, starting to supply the glass raw material into the glass melting furnace; and energized heating In the initial step, the glass raw material supplied is melted, and heating of the stored molten glass is started. The method for manufacturing a glass article according to item 3 of the patent application scope, wherein after the second temperature increase step is started, the electrical resistivity of the molten glass stored in the glass melting furnace is lower than that of the refractory After that, the electric heating start step is performed. The method for manufacturing a glass article as described in item 4 of the patent application range, wherein the refractory includes a refractory having a resistivity of 800 Ω·cm or more at 1400°C. The method for manufacturing a glass article as described in item 5 of the patent application range, wherein the resistivity of the molten glass is less than 2000 Ω·cm at 1400°C. The method for manufacturing a glass article according to any one of claims 3 to 6, wherein after the start of the second temperature raising step, the temperature in the glass melting furnace is increased to enable the After the temperature at which the glass raw material melts, the raw material supply start step is performed. The method for manufacturing a glass article according to any one of claims 1 to 7, wherein the air burner is stopped after the second temperature increase step is started. The method for manufacturing a glass article according to any one of claims 1 to 8, wherein in the continuous generation step, the molten glass is heated only by energized heating.

Images