Method for producing optical glass

Abstract

The application provides a manufacturing method of optical glass, which can effectively improve the glass quality in time when the melting furnace type of the glass is changed. The manufacturing method of optical glass comprises the following steps: melting, clarifying and stirring the glass raw material by using an optical glass manufacturing device, and heating the molten glass by using a heating electrode. When the molten pool of the glass is adjusted from molten pool a to molten pool b, the current Ib of the heating electrode of the molten pool b is: the application can provide a reference basis for setting the current of the heating electrode when the melting furnace type is adjusted, reduce the risk of glass quality rejection, and avoid adjusting the current of the heating electrode when the glass quality problem occurs, so that the glass quality and the yield can be effectively improved in time.

Description

Technical Field

[0001] This invention belongs to the field of glass manufacturing technology, and specifically relates to a method for manufacturing optical glass. Background Technology

[0002] With the increasing demand for high-definition imaging in optoelectronic applications, the quality requirements for optical glass, a crucial component, are becoming increasingly stringent, particularly regarding issues such as bubbles and streaks. Simultaneously, competition in the optical glass industry is intensifying. Therefore, improving product quality, ensuring yield, and maximizing return on investment have become critical challenges for the industry.

[0003] The existing optical glass manufacturing method involves continuously or intermittently feeding glass raw materials into a melting chamber. After the raw materials are burned in an atmosphere and melted, they are heated by heating electrodes for a period of time and then flow out from the melting outlet into a clarification tank for operations such as heating to eliminate bubbles before being introduced into the discharge tank for glass homogenization treatment.

[0004] Electrode heating effectively melts glass and significantly impacts its internal quality and striation characteristics. Current research on electrode heating is limited, with current adjustments relying heavily on experience. Adjustments are made only after feedback from glass quality, and even then, the glass quality in the molten pool requires time to change. Improper electrode heating settings can lead to prolonged glass spoilage, negatively impacting product quality and return on investment. This is especially true when the furnace type changes, such as from a large to a small molten pool, making it crucial to refine the electrode current setting. Furthermore, the viscosity of the glass changes with temperature during its passage through the discharge pool, resulting in striations. Therefore, improving the uniformity of the glass in the discharge pool is also essential. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for manufacturing optical glass, which can improve the quality of glass in a timely and effective manner when the type of glass melting furnace changes.

[0006] The technical solution adopted by this invention to solve the technical problem is: a method for manufacturing optical glass, which uses an optical glass manufacturing apparatus to melt, clarify, and stir the glass raw materials before discharging; and uses a heating electrode to heat the molten glass. When the glass melting pool is adjusted from melting pool a to melting pool b, the current Ib of the heating electrode in melting pool b is:

[0007]

[0008] Wherein, Ia is the current of the heating electrode of melting pool a, and Ia is the current of the heating electrode of melting pool b; La is the distance between the two symmetrically installed anodes and cathodes of the heating electrode of melting pool a, and Lb is the distance between the two symmetrically installed anodes and cathodes of the heating electrode of melting pool b; Ha is the height of the melting pool at the heating electrode mounting surface of melting pool a, and Hb is the height of the melting pool at the heating electrode mounting surface of melting pool b; Wa is the width of the melting pool at the heating electrode mounting surface of melting pool a, and Wb is the width of the melting pool at the heating electrode mounting surface of melting pool b; Ta is the theoretical residence time of the molten glass in melting pool a, and Tb is the theoretical residence time of the molten glass in melting pool b; A is the current adjustment coefficient of the heating electrode, where A is 0 to 1.

[0009] Furthermore, A is 0 to 0.8. When the content of Li2O, Na2O and K2O in the glass raw material is less than or equal to 15% by mass percentage (Li2O + Na2O + K2O), A is 0 to 0.5.

[0010] Furthermore, the process of melting, clarifying, and agitating the glass raw materials using the optical glass manufacturing apparatus includes the following steps: The glass raw materials are continuously or intermittently fed into the melting chamber from the feeding section through the melting pool cover; the glass raw materials are first heated by a burner and melted into molten glass, which flows into the melting chamber; then, the molten glass is heated by heating electrodes to maintain its temperature at 1050–1400°C; the molten glass enters the clarifying tank through a first connecting pipe, where the temperature is controlled at 1250–1500°C to eliminate air bubbles; the clarified glass enters the discharge tank through a second connecting pipe, where streaks are eliminated at a temperature of 1150–1350°C and a stirring speed of 10–70 r / min; finally, the molten glass flows continuously from the bottom discharge pipe of the discharge tank, forming strip glass products.

[0011] Furthermore, the optical glass manufacturing apparatus includes a melting pool, heating electrodes, a first connecting pipe, a refining pool, a second connecting pipe, and a discharge pool. The upper part of the melting pool is provided with a melting pool cover with an arched roof, and a burner is provided on the melting pool cover. The inner cavity of the melting pool is a melting chamber, and a heating electrode is provided inside the melting chamber. A discharge port is provided on the side wall of the melting chamber. The refining pool is connected to the discharge port of the melting pool through the first connecting pipe. The discharge pool is connected to the refining pool through the second connecting pipe, and a stirrer is installed in the discharge pool.

[0012] Furthermore, the agitator is a paddle agitator, a turbine agitator, a frame agitator, or a spiral agitator.

[0013] Furthermore, the optical glass manufacturing apparatus also includes a gas supply device and a control system for supplying combustion gas and combustion gas, wherein the outlet of the gas supply device is connected to the inlet of the burner.

[0014] Furthermore, the volume of the melting chamber is 50 to 3000 L.

[0015] Furthermore, the heating electrode includes symmetrically arranged anodes and cathodes, and the number of anodes and cathodes is two or more.

[0016] Furthermore, the anode and cathode of the heating electrode are respectively inserted into the two symmetrical side walls of the melting chamber and installed horizontally, and the height of the heating electrode from the bottom surface of the melting chamber is 0.3 to 0.5 times the height of the melting chamber.

[0017] The beneficial effects of this invention are: the formula for adjusting the heating electrode current of the melting pool can provide a reference for setting the heating electrode current when adjusting the melting furnace type, reducing the risk of glass quality scrap and avoiding the need to adjust the heating electrode current when glass quality problems occur, thereby improving glass quality and yield in a timely and effective manner; the addition of a stirrer to the discharge pool can effectively improve the uniformity of the glass itself and improve the quality of glass stripes. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the optical glass manufacturing apparatus used in this invention. Detailed Implementation

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] The manufacturing method of the optical glass of the present invention is as follows: Glass raw materials are melted using an optical glass manufacturing apparatus. The optical glass manufacturing apparatus includes a melting pool 1, a heating electrode 4, a first connecting pipe 8, a refining pool 9, a second connecting pipe 10, and a discharge pool 11, as shown below. Figure 1 As shown, the melting pool 1 is an apparatus for melting optical glass, which can realize the transformation from raw materials to molten glass. The upper part of the melting pool 1 is provided with a melting pool cover 3 with an arched top. The melting pool cover 3 is also provided with a burner 5, which can spray flames from its burner to heat and melt the glass raw materials. The inner cavity of the melting pool 1 is a melting chamber 2 for heating the molten glass. The melting chamber 2 is provided with a heating electrode 4 for heating the molten glass. The side wall of the melting chamber 2 is provided with a discharge port 7 to discharge the molten glass into a refining pool 9. The refining pool 9 is connected to the discharge port 7 of the melting pool 1 through a first connecting pipe 8. The discharge pool 11 is connected to the refining pool 9 through a second connecting pipe 10. The discharge pool 11 is equipped with an agitator 12 to eliminate streaks. The agitator 12 can be a paddle agitator, a turbine agitator, a frame agitator, or a spiral agitator. The discharge pool 11 is used to eliminate glass streaks and continuously discharge glass.

[0021] The melting pool 1 is usually made of high-temperature and corrosion-resistant materials, such as refractory bricks and ceramics, to resist the corrosion of raw materials. It is preferably made of high-temperature and corrosion-resistant ceramic materials with alumina (Al2O3), quartz (SiO2), clay (Al2O3+SiO2) and zirconium oxide (ZrO2) as the main components. The melting chamber 2 is used to store the glass melt, and its volume is preferably 50-3000L. The parts that come into direct contact with the glass melt, such as the clarifying pool 9, the discharge pool 11, the first connecting pipe 8, the second connecting pipe 10, and the agitator 12, are all made of precious metals or precious metal alloys, preferably platinum or platinum alloys.

[0022] The aforementioned optical glass manufacturing apparatus typically also includes a gas supply device and a control system for supplying combustion gas and oxidizing gas. The outlet of the gas supply device is connected to the inlet of the burner 5. The combustion gas is preferably methane, ethane, natural gas, or a mixture of several combustible gases. Considering production costs, natural gas is further preferred as the combustion gas. The combustion gas is preferably oxygen, air, or other oxygen-containing mixtures.

[0023] The aforementioned heating electrode 4 primarily heats the molten glass using an electric current. The heating electrode 4 is typically a cylindrical or columnar structure with a polygonal or circular cross-section. The heating electrode 4 is made of materials such as tin oxide, platinum, molybdenum, or their alloys. Considering manufacturing costs and corrosion resistance, tin oxide is preferred for the heating electrode 4. The heating electrode 4 includes symmetrically installed anodes and cathodes, with two or more anodes and cathodes. The anodes and cathodes of the heating electrode 4 are inserted horizontally from two symmetrical sidewalls of the melting chamber 2, and the height of the heating electrode 4 from the bottom surface of the melting chamber 2 is 0.3 to 0.5 times the height of the melting chamber 2. The side of the melting pool 1 where the heating electrode 4 is installed is called the heating electrode mounting surface. The height of the melting pool on the heating electrode mounting surface refers to the height of this heating electrode mounting surface, and the width of the melting pool on the heating electrode mounting surface refers to the width of this heating electrode mounting surface.

[0024] Electrode heating, as a crucial auxiliary method for melting the glass in the melting pool, has a significant impact on the intrinsic quality of the glass. Excessive electrode current leads to overly efficient glass melting and high temperatures, which can cause surface glass to flow into the interior, resulting in internal defects and streaks. Conversely, insufficient electrode current makes powder melting difficult, resulting in high glass gas content and viscosity, further contributing to internal and streak problems. Currently, electrode current settings largely rely on experience, with adjustments made only after feedback on glass quality. Even after adjustments, the glass quality in the melting pool requires time to change. Improper electrode heating settings can lead to prolonged glass scrapping, negatively impacting product quality and input-output efficiency. In particular, when the type of glass melting furnace changes, such as from a large melting pool to a small one or vice versa, the electrode current settings cannot be simply reused. To ensure product quality and return on investment, the inventors, drawing on practical experience in glass melting, discovered through years of research that when the glass melting process is adjusted from melting pool a to melting pool b, the current Ib of the heating electrode 4 in melting pool b can be set in the following manner:

[0025]

[0026] Wherein, Ia is the current of the heating electrode 4 in melting pool a, and lb is the current of the heating electrode 4 in melting pool b; La is the distance between the two symmetrically installed anodes and cathodes of the heating electrode 4 in melting pool a, and Lb is the distance between the two symmetrically installed anodes and cathodes of the heating electrode 4 in melting pool b; Ha is the height of the melting pool at the heating electrode mounting surface of melting pool a, and Hb is the height of the melting pool at the heating electrode mounting surface of melting pool b; Wa is the width of the melting pool at the heating electrode mounting surface of melting pool a, and Wb is the width of the melting pool at the heating electrode mounting surface of melting pool b; Ta is the theoretical residence time of the molten glass in melting pool a, and Tb is the theoretical residence time of the molten glass in melting pool b; A is the current adjustment coefficient of the heating electrode 4, and A ranges from 0 to 1, preferably from 0 to 0.8. In particular, when the content of Li2O, Na2O and K2O in the glass raw material is less than or equal to 15% by mass, A is preferably from 0 to 0.5. The distance between the anode and cathode mentioned above refers to the distance from the top of the anode to the top of the cathode; the theoretical residence time mentioned above is the time from when the powder is continuously or intermittently fed into the melting chamber 2 through the melting pool cover 3 from the time when the powder is formed into glass and flows out from the outlet 7.

[0027] The manufacturing method of optical glass of the present invention includes the following steps: glass raw material is continuously or intermittently fed into the melting chamber 2 from the feeding section 6 through the melting pool cover 3. During feeding, the feeding is limited to the extent that it does not hinder the continuous flow of molten glass from the outlet of the melting pool into the next process at a certain flow rate; the glass raw material is first heated by the flame sprayed from the burner 5 and melted into molten glass, which flows into the melting chamber 2. Then, the molten glass is heated by the heating electrode 4 to keep the temperature of the molten glass at 1050-1400°C; the molten glass enters the refining tank 9 through the first connecting pipe 8. The temperature of the molten glass in the refining tank 9 is controlled at 1250-1500°C to carry out a refining step to eliminate bubbles in the molten glass; the refined molten glass enters the discharge tank 11 through the second connecting pipe 10. At a temperature of 1150-1350°C, the stirrer 12 stirs at a speed of 10-70 r / min to eliminate streaks. Then, the molten glass flows out continuously from the bottom discharge pipe of the discharge tank 11 to form strip glass products.

Claims

1. A method for manufacturing optical glass, comprising melting, clarifying, and stirring glass raw materials using an optical glass manufacturing apparatus, characterized in that, The molten glass is heated using a heating electrode (4). When the molten pool (1) of the glass is adjusted from molten pool a to molten pool b, the current Ib of the heating electrode (4) in molten pool b is: Wherein, Ia is the current of the heating electrode (4) of melting pool a, and Ib is the current of the heating electrode (4) of melting pool b; La is the distance between the two symmetrically installed anodes and cathodes of the heating electrode (4) of melting pool a, and Lb is the distance between the two symmetrically installed anodes and cathodes of the heating electrode (4) of melting pool b; Ha is the height of the melting pool at the heating electrode mounting surface of melting pool a, and Hb is the height of the melting pool at the heating electrode mounting surface of melting pool b; Wa is the width of the melting pool at the heating electrode mounting surface of melting pool a, and Wb is the width of the melting pool at the heating electrode mounting surface of melting pool b; Ta is the theoretical residence time of the molten glass in melting pool a, and Tb is the theoretical residence time of the molten glass in melting pool b; A is the current adjustment coefficient of the heating electrode (4), where A is 0 to 1.

2. The method for manufacturing optical glass as described in claim 1, characterized in that, The value of A is 0 to 0.

8.

3. The method for manufacturing optical glass as described in claim 1, characterized in that, When the content of Li2O, Na2O and K2O in the glass raw material is less than or equal to 15% by mass, the A is 0 to 0.

5.

4. The method for manufacturing optical glass as described in claim 1, characterized in that, The process of melting, clarifying, and stirring the glass raw materials using the optical glass manufacturing apparatus includes the following steps: the glass raw materials are continuously or intermittently fed into the melting chamber (2) from the feeding section (6) through the melting pool cover (3); the glass raw materials are first heated by the burner (5) and melted into molten glass, which flows into the melting chamber (2), and then heated by the heating electrode (4) to keep the temperature of the molten glass at 1050-1400℃; the molten glass enters the clarifying pool (9) through the first connecting pipe (8), and the temperature of the molten glass in the clarifying pool (9) is controlled at 1250-1500℃ to eliminate bubbles in the molten glass; the clarified molten glass enters the discharge pool (11) through the second connecting pipe (10), and at a temperature of 1150-1350℃, the stirrer (12) stirs at a speed of 10-70 r / min to eliminate streaks, and then the molten glass flows out continuously from the bottom discharge pipe of the discharge pool (11) to form strip glass products.

5. The method for manufacturing optical glass as described in claim 1, characterized in that, The optical glass manufacturing apparatus includes a melting pool (1), a heating electrode (4), a first connecting pipe (8), a refining pool (9), a second connecting pipe (10), and a discharge pool (11). The upper part of the melting pool (1) is provided with a melting pool cover (3) with an arched top, and a burner (5) is provided on the melting pool cover (3). The inner cavity of the melting pool (1) is a melting chamber (2), and the heating electrode (4) is provided in the melting chamber (2). The discharge port (7) is provided on the side wall of the melting chamber (2). The refining pool (9) is connected to the discharge port (7) of the melting pool (1) through the first connecting pipe (8). The discharge pool (11) is connected to the refining pool (9) through the second connecting pipe (10), and a stirrer (12) is installed in the discharge pool (11).

6. The method for manufacturing optical glass as described in claim 5, characterized in that, The agitator (12) is a paddle agitator, turbine agitator, frame agitator or spiral agitator.

7. The method for manufacturing optical glass as described in claim 5, characterized in that, The optical glass manufacturing apparatus further includes a gas supply device and a control system for supplying combustion gas and combustion gas, wherein the outlet of the gas supply device is connected to the inlet of the burner (5).

8. The method for manufacturing optical glass as described in claim 4 or 5, characterized in that, The volume of the melting chamber (2) is 50 to 3000 L.

9. The method for manufacturing optical glass as described in claim 4 or 5, characterized in that, The heating electrode (4) includes symmetrically installed anodes and cathodes, and the number of anodes and cathodes is two or more.

10. The method for manufacturing optical glass as described in claim 4 or 5, characterized in that, The anode and cathode of the heating electrode (4) are respectively installed horizontally from the two symmetrical side walls of the melting chamber (2), and the height of the heating electrode (4) from the bottom surface of the melting chamber (2) is 0.3 to 0.5 of the height of the melting chamber (2).

Images