Glass manufacturing method

Abstract

To provide a glass production method of which the temperature can be easily and quickly raised and lowered and the productivity can be enhanced.SOLUTION: The glass production method according to the present invention comprises the steps for melting a starting material disposed in a container 1 to form a melt 11 and for cooling the melt 11 to give a glass. The starting material contains a metal. In the step for converting the starting material into the melt 11, the starting material is induction-heated.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a method for producing glass. [Background technology]

[0002] In recent years, chalcogenide glass has been known as a material that is preferably used in the field of infrared optics. Chalcogenide glass is not only transparent to infrared rays, but also has advantages in terms of mass productivity and cost reduction due to its applicability to mold presses.

[0003] Patent Document 1 discloses an example of a method for producing chalcogenide glass, which describes a method for producing chalcogenide glass in which glass components in a crucible are heated and melted by radiant heat from a heater, and the molten liquid is stirred by a stirring rod. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4109105 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the method described in Patent Document 1 requires the heater to be heated to a sufficiently high temperature, and the glass component to be heated to a target temperature by the radiant heat, making it difficult to raise the temperature at a sufficiently high speed.

[0006] On the other hand, when lowering the temperature of the glass components to a target temperature, for example, when a method of switching a heater on and off is used, even if the heater is turned off, the glass components continue to be heated for a while by the radiant heat from the heater, making it difficult to lower the temperature sufficiently quickly.

[0007] An object of the present invention is to provide a method for producing glass, which can easily and quickly raise and lower the temperature and can increase productivity. [Means for solving the problem]

[0008] The method for producing glass according to the present invention includes a step of melting raw materials placed in a container to obtain a molten liquid, and a step of obtaining glass by cooling the molten liquid, and is characterized in that the raw materials contain metal, and the raw materials are induction heated in the step of obtaining a molten liquid from the raw materials.

[0009] It is preferable that the method further comprises the step of stirring the melt, and stirs the melt by Lorentz force.

[0010] The method preferably further comprises a step of causing the melt to flow out of the container through a pipe, the pipe being connected to the container, a plug being disposed in the pipe, and the melt being caused to flow out by heating and melting the plug. In this case, it is more preferable that the plug is a solidified material formed by cooling the melt in the pipe.

[0011] Preferably, the glass is a chalcogenide glass. Effect of the Invention

[0012] According to the present invention, it is possible to provide a method for producing glass, which enables easy and rapid temperature increase and decrease and thus improves productivity. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1(a) to (c) are schematic perspective views illustrating a process for producing glass according to one embodiment of the present invention up to a step of heating raw materials. [Diagram 2] 1(a) and 1(b) are schematic perspective views illustrating a process subsequent to stirring the melt in a method for producing glass according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Preferred embodiments will be described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. In addition, in the drawings, components having substantially the same functions may be referred to by the same reference numerals.

[0015] (Glass manufacturing method) Figures 1(a) to 1(c) are schematic perspective views for explaining a process up to a step of heating raw materials in a glass manufacturing method according to one embodiment of the present invention. Figures 2(a) and 2(b) are schematic perspective views for explaining a process after a step of stirring a molten liquid in a glass manufacturing method according to one embodiment of the present invention. For convenience, coil 10A or coil 10B is omitted in some of the drawings.

[0016] The manufacturing method of this embodiment is a method for manufacturing chalcogenide glass as one example of the present invention, although the method of the present invention can also be applied to the manufacture of glasses other than chalcogenide glass.

[0017] As shown in Fig. 1(a), in this embodiment, a crucible is used as the container 1. The container 1 has a bottom 2 and a side wall 3. The container 1 is preferably made of quartz glass. This allows glass to be formed suitably in the following steps.

[0018] A pipe 4 is connected to the bottom 2 of the container 1. An outer tube 5 is disposed so as to surround the pipe 4. The pipe 4 passes through the inside of the outer tube 5. In this embodiment, the outer tube 5 is made of Pt. However, the outer tube 5 may be made of any suitable metal.

[0019] As shown in FIG. 1(a), glass raw material 6 is placed in container 1. In this embodiment, raw material 6 is a mixture containing components that constitute chalcogenide glass. In the present invention, raw material 6 may contain metal. In the present invention, "metal" includes metal elements, semimetal elements, alkali metal elements, alkaline earth metal elements, and the like. Details of raw material 6 will be described later. It is preferable to melt a small amount of raw material 6 in advance to make a small amount of molten liquid 11, and to allow the small amount of molten liquid 11 to flow into pipe 4. The small amount of molten liquid 11 is cooled in pipe 4 and becomes a solidified material (solid glass). This allows plug 12 to be formed. This allows raw material 6 to be stably placed even if pipe 4 is connected to bottom 2 of container 1.

[0020] Next, as shown in FIG. 1(b), a lid 7 is placed on the side wall 3 of the container 1. A gas supply pipe 8 and a gas exhaust pipe 9 are connected to the lid 7. Gas is exhausted from the container 1 through the gas exhaust pipe 9 to reduce the pressure. Next, an inert gas or a reducing gas is supplied into the container 1 through the gas supply pipe 8. By repeating this process, the inside of the container 1 is made into an inert atmosphere or a reducing atmosphere.

[0021] When forming chalcogenide glass, it is necessary to prevent the heated raw material 6 from reacting with oxygen or moisture. In this embodiment, the air in the container 1 is replaced with an inert gas or a reducing gas, so that oxygen and moisture are removed from the container. Therefore, chalcogenide glass can be suitably formed without using a sealed container kept in a vacuum state. In this embodiment, as described later, the formed glass can be discharged from the container 1 through the pipe 4, so that it is not necessary to destroy the container 1 to take out the formed glass, and the container 1 can be reused.

[0022] Incidentally, as shown in FIG. 1(c), coil 10A is arranged so as to surround at least a part of side wall 3 of container 1. Specifically, coil 10A is arranged so as to surround the part of container 1 where raw material 6 is placed. Raw material 6 is induction-heated by passing a current through coil 10A. Specifically, an induced magnetic field generated by passing a current through coil 10A generates an induced current. Raw material 6 contains a metal, and metal has an internal resistance. Therefore, when an induced current flows through the metal, the metal contained in raw material 6 becomes a heat source, and the entire raw material 6 is heated. This induction heating turns raw material 6 into a melt 11 as shown in FIG. 2(a).

[0023] By passing a current through coil 10A, an induced magnetic field and an induced current are generated, and a Lorentz force is applied to melt 11. This Lorentz force can stir melt 11. In this manner, in this embodiment, melt 11 can be stirred without using a means for stirring melt 11 by directly contacting a member therewith, such as a stirrer. However, a stirrer or the like may also be used to stir melt 11.

[0024] As described above, a part of the melt 11 flows into the pipe 4. The melt 11 in the pipe 4 is cooled and solidifies (solid glass). This forms the plug 12. Therefore, a small amount of the melt 11 sufficient to form the plug 12 flows into the pipe 4, but the outflow of the remaining melt 11 is stopped by the plug 12. However, a lid, a plunger, or the like may be used instead of the plug 12.

[0025] As shown in FIG. 2(b), a coil 10B is disposed around the outer tube 5. By passing a current through the coil 10B, the outer tube 5 is induction heated. The pipe 4 and the plug 12 in the pipe 4 are heated by radiant heat from the outer tube 5. Note that the plug 12 is solid glass and does not contain a simple metal or alloy, and is therefore not induction heated. The plug 12 melts as a result of the above heating, and the molten liquid 11 flows out of the container 1.

[0026] The melt 11 that has flowed out is poured into, for example, an appropriate mold, and then cooled in the mold to form glass.

[0027] The feature of this embodiment is that the raw material 6 contains a metal, and the raw material 6 is melted by induction heating. By adjusting the current flowing through the coil 10A, the degree of heat generation of the metal contained in the raw material 6 or the melt can be adjusted, and the temperature of the raw material 6 or the melt 11 can be directly adjusted. Therefore, the temperature can be increased or decreased more easily and quickly than in conventional heating by radiation. This can increase productivity.

[0028] As shown in Fig. 2(a), it is preferable to stir melt 11 by Lorentz force. When melt 11 is stirred by Lorentz force without using a stirring member, the stirring member does not come into contact with melt 11. Therefore, melt 11 is less likely to be contaminated. Therefore, the purity of the formed glass can be increased.

[0029] The pipe 4 does not necessarily have to be connected to the vessel 1. However, by connecting the pipe 4 to the vessel 1, the melt 11 can be easily discharged without changing the attitude of the vessel 1.

[0030] The plug 12 in the pipe 4 is preferably formed by solidifying the melt 11 cooled in the pipe 4. This makes it possible to stop the outflow of the melt 11 without using members such as a plunger or a lid. Therefore, since members such as a lid or a plunger do not come into contact with the melt 11, the melt 11 is less likely to be contaminated. This makes it possible to increase the purity of the glass to be formed.

[0031] When using a member such as a plunger or a lid, it is necessary to place the member in an appropriate position with a size that completely blocks the pipe 4. Therefore, high precision is required for the size and placement of the member. In contrast, the plug 12 is formed by solidifying the molten liquid 11 that has flowed into the pipe by cooling, and therefore can more reliably and easily block the pipe 4.

[0032] The ratio of materials contained in raw material 6 of this embodiment is adjusted so as to obtain glass having the following composition. In the explanation of the glass composition, "%" means "mol %." For example, the total content of A, B, and C may be expressed as "content of A+B+C" or "A+B+C."

[0033] The glass formed by the method of the present embodiment has a glass composition containing, in molar ratios, more than 0% to 50% Ge, more than 0% to 50% Ga, 30% to 90% Te, 0% to 40% Ag+Al+Ti+Cu+In+Sn+Bi+Cr+Zn+Mn, and 0% to 50% F+Cl+Br+I.

[0034] Ge is a component for forming a glass skeleton. Ge is a semimetal element. The Ge content is more than 0% to 50%, preferably 2% to 40%, more preferably 4% to 35%, even more preferably 5% to 30%, even more preferably 7% to 25%, and even more preferably 10% to 20%. If the Ge content is too low, vitrification becomes difficult. On the other hand, if the Ge content is too high, Ge-based crystals tend to precipitate easily and the raw material cost tends to increase.

[0035] Ga is a component for increasing the thermal stability (vitrification stability) of glass. Ga is a metal element. The Ga content is more than 0% to 50%, preferably 1% to 45%, more preferably 2% to 40%, even more preferably 4% to 30%, even more preferably 5% to 25%, and even more preferably 10% to 20%. If the Ga content is too low, vitrification becomes difficult. On the other hand, if the Ga content is too high, Ga-based crystals tend to precipitate easily and the raw material cost tends to increase.

[0036] Te, a chalcogen element, is a component that is essential for forming a glass skeleton. Te is also a metalloid element. The content of Te is 30% to 90%, preferably 40% to 89%, more preferably 50% to 88%, even more preferably 60% to 86%, and even more preferably 70% to 85%. If the content of Te is too low, vitrification becomes difficult. On the other hand, if the content of Te is too high, Te-based crystals are likely to precipitate.

[0037] Ag+Al+Ti+Cu+In+Sn+Bi+Cr+Zn+Mn are metal elements. The glass contains the above metal elements, which can enhance thermal stability. The content of Ag+Al+Ti+Cu+In+Sn+Bi+Cr+Zn+Mn is 0% to 40%, preferably more than 0% to 30%, more preferably more than 0% to 20%, and even more preferably 0.1% to 10%. If the content of Ag+Al+Ti+Cu+In+Sn+Bi+Cr+Zn+Mn is too low or too high, vitrification becomes difficult. The content of each component of Ag+Al+Ti+Cu+In+Sn+Bi+Cr+Zn+Mn is 0% to 40%, preferably 0% to 30% (at least one of them is more than 0%), more preferably 0% to 20% (at least one of them is more than 0%), and even more preferably 0.1% to 10%. Among these, it is preferable to use Ag and / or Sn since they have a particularly large effect of increasing the thermal stability of the glass.

[0038] The glass formed in this embodiment may contain the following components in addition to the above components.

[0039] F, Cl, Br, and I are also components that enhance the thermal stability of glass. The contents of F, Cl, Br, and I are 0% to 50%, preferably 1% to 40%, more preferably 1% to 30%, even more preferably 1% to 25%, and particularly preferably 1% to 20%. If the content of F+Cl+Br+I is too high, vitrification becomes difficult and weather resistance is easily reduced. The contents of each of F, Cl, Br, and I are each 0% to 50%, preferably 1% to 40%, more preferably 1% to 30%, even more preferably 1% to 25%, and particularly preferably 1% to 20%. Among them, it is preferable to use I, since elemental raw materials can be used and the effect of enhancing glass stability is particularly large.

[0040] By including Si, Sb, and Cs, the thermal stability can be improved. Here, Si and Sb are semimetals. The content of Si+Sb+Cs is preferably 0% to 40%, more preferably 0% to 30%, even more preferably 0% to 20%, and even more preferably 0.1% to 10%.

[0041] S is a component that expands the vitrification range and tends to increase the thermal stability of glass. Its content is preferably 0% to 30%, more preferably 0% to 20%, further preferably 0% to 10%, and particularly preferably 0% to 3%. If the S content is too high, the transmittance of infrared rays having a wavelength of 10 μm or more tends to decrease.

[0042] Se and As are components that expand the vitrification range and increase the thermal stability of glass. The content of each of these elements is preferably 0% to 10%, and more preferably 0.5% to 5%. However, since these substances are toxic, it is preferable that they are not substantially contained from the viewpoint of reducing the impact on the environment and human body, as described above.

[0043] It is preferable that the above glass does not substantially contain the toxic substances Cd, Tl and Pb.

[0044] The ratio of metal in the raw material 6 is preferably 80% or more, 85% or more, particularly 90% or more, by volume. In this way, the raw material 6 can be easily melted by induction heating. Therefore, compared to conventional heating by radiation, the temperature can be increased or decreased more easily and quickly, and productivity can be improved. There is no particular upper limit, but it can be, for example, 100% or less, 99% or less, particularly 98% or less. [Explanation of symbols]

[0045] 1…Container 2…Bottom 3…Side wall 4. Piping 5...Mantle tube 6...Raw materials 7…Lid 8...Gas supply pipe 9...Gas exhaust pipe 10A…Coil 10B…Coil 11…Melted liquid 12…Seal

Claims

1. A step of melting a glass raw material placed in a container to obtain a molten liquid; cooling the melt to obtain the glass; Equipped with The raw material of the glass contains a metal, the glass is a chalcogenide glass, The ratio of metal in the raw material of the glass is 80% or more by volume percent, The method for producing glass, wherein in the step of converting the glass raw material into the melt, the glass raw material is induction heated.

2. The method further comprises the step of stirring the melt, The method for producing glass according to claim 1 , wherein the melt is stirred by Lorentz force.

3. The melt is allowed to flow out of the vessel through a pipe, The piping is connected to the container, and a plug is disposed within the piping; The method for producing glass according to claim 1 , wherein the plug is heated and melted to allow the molten liquid to flow out.

4. The method for producing glass according to claim 3 , wherein the plug is a solidified product formed by cooling the molten liquid in the pipe.

5. The method for producing glass according to claim 1, wherein the glass contains, in mol%, 30% to 90% Te.

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