WO2013042969A1 - Method for manufacturing soda-lime-silicate plate glass and highly transparent plate glass manufactured by said method - Google Patents

Abstract

The present invention relates to a method for manufacturing soda-lime-silicate plate glass and to highly transparent plate glass manufactured by said method. More particularly, the present invention relates to a method for manufacturing soda-lime-silicate plate glass and to highly transparent plate glass manufactured by said method, wherein the method permits a glass material mixture batch to sequentially pass through a melter and a refiner which is located at the downstream of the melter, and performs cooling and molding processes to manufacture plate-type soda-lime-silicate glass, wherein an oxidant flow is introduced in at least one of the melter and the refiner separately from an operation of a burner.

Description

Method for producing soda lime silicate glass and high transparency glass glass produced thereby

The present invention relates to a method for producing soda lime silicate glass and to a high transparent glass produced thereby, and more particularly, a refiner located after the glass raw material mixture batch is melter and downstream to the melter. In the method for producing a soda-lime silicate glass in the form of a plate after successively passing through), the plate glass, characterized in that the flow of oxidant is introduced into at least one of the melter and refiner to separate the operation of the burner It relates to a manufacturing method of and a high transparent plate glass produced thereby.

Soda lime silicate glass with high visible light and high solar radiation transmittance may be usefully used as a cover glass and substrate of a solar cell, a window or interior material of a building. In particular, since the glass has a high visible light and solar radiation transmittance, when applied to the cover glass and substrate of the solar cell can increase the energy conversion efficiency of the solar cell. On the other hand, these glasses have a high visible light transmittance and are more colorless and transparent than ordinary glass, so they can be applied to interior glass such as building lobby or product display glass. Helps to see the sound without distortion.

Generally, silica, soda ash, dolomite, limestone, and the like are used as raw materials for manufacturing glass, and these raw materials contain Fe ₂ O ₃ as impurities. Therefore, soda lime silicate glass is produced by using these raw materials there is inevitably containing Fe ₂ O ₃ as an impurity, soda lime Fe ₂ O ₃ in the glass absorbs much of the sun's rays to visible light and solar radiation transmittance Dropped. Therefore, in order to manufacture soda-lime silicate glass having high visible light and high solar radiation transmittance, the Fe ₂ O ₃ content in the glass must be kept low. Therefore, a high purity raw material having a low content of Fe ₂ O ₃ has to be used in the past. . However, the use of ultra-high purity raw material containing only a few ppm of Fe ₂ O ₃ , the raw material price inevitably increases, there is a limit that it is difficult to apply to commercial glass production.

In order to be suitable for application to the cover glass and substrate of a solar cell, it must be a glass having a very high optical transmittance (eg, visible light transmittance of at least 91.2% and solar radiation transmittance of at least 90.6%) based on 4 mm glass thickness. Such high permeation glass can be achieved, for example, by reducing the total Fe ₂ O ₃ content in 100 parts by weight to 0.013 parts by weight or lowering the Redox ratio to 0.24 or less. Herein, the total Fe ₂ O ₃ content (Total Fe ₂ O ₃ ) means the content of all Fe ³⁺ and Fe ²⁺ in the form of Fe ₂ O ₃ in the glass, and the redox ratio represents Fe ²⁺ in the glass. The content in the form of FeO divided by the total Fe ₂ O ₃ content (that is, the redox ratio = FeO content / total Fe ₂ O ₃ content) means.

Visible light and solar radiation transmission in glass depend on both the total Fe ₂ O ₃ content and the redox ratio in the glass. Therefore, it is necessary to reduce either or both of them in order to achieve high visible and solar radiation transmittance in the glass. In glass, iron exists in two forms: ferrous oxide (FeO) in the reduced state and ferric oxide (Fe ₂ O ₃ ) in the oxidized form, and FeO and Fe ₂ O ₃ The balance between has a significant effect on the transmittance and color of the glass.

In general, FeO (Fe ²⁺ ) in glass has an absorption peak near 1050 nm, and as its content increases, the visible and solar radiation transmittances decrease considerably, and the glass tends to be colored in very light blue. . Fe ₂ O ₃ (Fe ³⁺ ) in the glass has multiple absorption peaks in the vicinity of 380 ~ 435nm, and as its content increases, the visible light transmittance and the solar radiation transmittance increase, the ultraviolet transmittance decreases slightly, and the glass is very light. It tends to color yellow.

Conventional uncoloured soda lime silicate glass is called Clear glass and usually has a total Fe ₂ O ₃ content of about 0.07 to 0.13 parts by weight per 100 parts by weight of glass. In addition, the clear glass manufactured by the conventional method has a redox ratio of 0.25-0.26. However, in the case of very small glass with a total Fe ₂ O ₃ content of 0.013 parts by weight or less per 100 parts by weight of glass, the glass is prepared by a conventional method, the redox ratio exceeds 0.3, and may be seriously increased to 0.4 to 0.5. have. This is a natural phenomenon as the equilibrium concentration between Fe ³⁺ and Fe ²⁺ is adjusted as the total Fe ₂ O ₃ content in the soda lime silicate glass is lowered.

The redox ratio is dependent on the raw material, melting temperature, melting atmosphere, holding time in the furnace, cooling rate, and the like. In particular, it is known that the atmosphere in the furnace tends to decrease in an oxidizing atmosphere and increases in a reducing atmosphere. In view of this, methods for using a variety of oxidants as raw materials for oxidizing the glass have been proposed in order to make the melting atmosphere into an oxidizing atmosphere in order to lower the redox ratio which is high in glass having a very low iron content.

Sodium lime silicate has been mainly used as a representative raw material for oxidizing soda lime silicate glass. However, this material decomposes in the early stage of melting when used in excess, forming a strong foam layer, which prevents the heat source of the burner from being transferred to the molten glass, which leads to a sharp decrease in energy efficiency.

Meanwhile, antimony oxide (Sb ₂ O ₃ ) and arsenic oxide (As ₂ O ₃ ), which are mainly used in glass such as borosilicate and boroaluminosilicate produced by the fusion downdraw method, are used in the float method, which is a typical method for manufacturing plate glass. It cannot be used because the antimony and arsenic contained in the glass can be reduced, causing defects on the glass surface.

US Patent No. 6,610,622 discloses a low iron glass having a total Fe ₂ O ₃ content of 0.01 to 0.3% by weight, and a glass composition using 0.01 to 0.3% by weight of Er ₂ O ₃ and 0.005 to 0.3% by weight of Ce ₂ O ₃ as a colorant component. Is disclosed. However, the glass composition disclosed in this patent contains the expensive rare earth element Er ₂ O ₃ as an essential component and thus is not suitable as a commercial plate glass.

The glass composition disclosed in U.S. Patent No. 6,610,622 is a material which oxidizes iron from ferrous iron (FeO) to ferric iron (Fe ₂ O ₃ ) when melting the glass, and contains cerium oxide (Ce ₂ O ₃ ) as an essential component. Also, US Patent No. 6,844,280 discloses a technique of adding cerium oxide (CeO ₂ ). Cerium oxide is known to be a strong oxide that oxidizes glass, but glass containing low iron and Ce turns brown after prolonged exposure to ultraviolet light, ie, changes in the optical transmission spectrum of glass during prolonged exposure to sunlight. Causes In other words, the use of cerium oxide in low iron glass adversely affects the long-term color stability of the glass, which is particularly useful for soda-lime silicate glass for use in glass and substrates for long exposure to external sunlight. Means that it is not suitable to use cerium oxide.

Meanwhile, instead of using various oxidant materials as glass raw materials as described above, an excessive amount of oxidant (for example, oxygen or air) is injected together with the fuel in the burner to inject the fuel into the melting furnace to completely burn the fuel. Has been proposed in US Patent Application Publication No. 2011/135938. It is described here to achieve a low redox ratio by supplying a superstoichiometric amount of oxidant with fuel to at least one burner located at the bottom of the furnace. However, when an overstoichiometric amount of oxidant (eg oxygen) is added to a running burner, excess oxygen is supplied beyond the theoretical amount of oxygen required for the combustion of the fuel, which inevitably lowers the temperature inside the furnace, and to compensate for this, Since a large amount of fuel and air have to be injected, it is very weak in terms of energy efficiency of the furnace. In addition, supplying an overstoichiometric amount of oxygen directly to an operating burner port may change the combustion conditions near the burner depending on the flow rate, and in some cases, the excess oxygen supplied does not contribute to the formation of an oxidizing atmosphere. Since it can be released, the level of oxidizing atmosphere actually formed may differ from the prediction. In other words, supplying an overstoichiometric amount of oxygen directly to an operating burner port has a problem that it is difficult to control the oxidizing atmosphere to a desired level.

<Preceding technical literature>

<Patent Documents>

(Patent Document 1) US Patent No. 6,610,622

(Patent Document 2) US Patent No. 6,844,280

(Patent Document 3) United States Patent Application Publication No. 2011/135938

The present invention is directed to solving the problems of the prior arts as described above, and an object of the present invention is to provide metal oxides and lanthanide element oxides as oxidants in the preparation of soda lime silicate glass having a very low total Fe ₂ O ₃ content. It is a technical object of the present invention to provide a method for producing soda lime silicate glass having a very high visible light transmittance and a solar radiation transmittance by effectively lowering the redox ratio of the glass without using the present invention, and a high transparent plate glass produced thereby. .

In order to achieve the above technical problem, the present invention continuously passes a batch of glass raw material mixture (melter) and a refiner located downstream of the melter, and then cools and molds the plated soda. A method of making lime silicate glass, wherein the melter melts the glass raw material mixture batch by injecting a plurality of burners with a stoichiometric amount of fuel material and a stoichiometric amount of oxidant, At least one of the melter and the refiner is introduced with a separate oxidant flow from the operation of the burner, the plate-like soda lime, characterized in that the total content of Fe ₂ O ₃ of the glass produced is 0 to 0.013 parts by weight per 100 parts by weight of glass. Provided is a method for producing silicate glass.

According to another aspect of the present invention, the glass manufacturing method of the present invention, which is 65 to 75 parts by weight of SiO ₂ , 0.1 to 3 parts by weight of Al ₂ O ₃ , Na ₂ O and K ₂ O per 100 parts by weight of glass Soda with 10 to 18 parts by weight, CaO 5 to 15 parts by weight, MgO 1 to 6 parts by weight, SO ₃ 0.01 to 0.5 part by weight, and total Fe ₂ O ₃ 0 to 0.013 part by weight, and a redox ratio of 0.05 to 0.24. Lime silicate panes are provided.

According to the present invention, in the preparation of soda-lime silicate glass having a very low total Fe ₂ O ₃ content, it is possible to effectively lower the redox ratio of the glass without the use of metal oxides and lanthanide element oxides as oxidants, thereby providing very high visible light. Soda-lime silicate panes with transmittance and solar radiation transmittance can be prepared.

1 is a schematic view of one embodiment of a soda lime silicate glass manufacturing method according to the present invention.

Figure 2 is a schematic diagram of another embodiment of the soda lime silicate glass manufacturing method according to the present invention.

Figure 3 is a schematic diagram of yet another embodiment of the method for producing soda lime silicate glass according to the present invention.

Hereinafter, the present invention will be described in more detail.

The present invention can be applied to the manufacturing process of soda-lime silicate plate glass having a very high visible light and solar radiation transmittance. Representative methods of manufacturing the plate glass include the float (Float) method, roll-out (Fusion down draw) method, the down draw (Down draw) method, the up draw (Up draw) method, etc. The application of the present invention is not limited thereto.

The present invention basically relates to a process for producing a glass-like mixture of soda-lime silicate after passing the batch of glass stock mixture continuously through a melter and a refiner located subsequent to the melter, followed by cooling and forming.

Plate glass manufacturing method of the present invention can be carried out using a continuous equipment as shown in Figures 1 to 3, but is not limited thereto. In the melter of the continuous installations usable in the present invention, it is preferable that at least two burners (an apparatus for injecting fuel or a mixture of fuel and gas into the melting furnace) are provided on both sides of the melter. As a heat source, fossil fuels in the form of oil or gas may be used. Oxygen is preferable as the oxidant required for burning such fossil fuel, and oxygen may be introduced into the melter in the form of pure oxygen or in the form of atmospheric air or pure oxygen and air. It is also possible to additionally inject oxidants (eg pure oxygen or atmospheric air or a mixture of pure oxygen and air) in the burner together with the fossil fuel for effective injection of the fossil fuel. An electrical heat source may also be supplied to the bottom of the melter to assist in melting the batch of glass stock mixture. Continuous equipment that can be utilized in the present invention, but may be employed in the combustion system commonly known in the art, such as regenerator method, oxy-firing method, oxy-boosting method, but is not limited thereto.

The continuous equipment usable in the present invention is largely for forming a glass melt exiting a melting-refining zone and a melting-clarifying section, in which raw material batches are introduced into a melting furnace, where melting, clarification and homogenization are performed. It is divided into two parts, the working end, which cools to an appropriate temperature. The melt-clarification section is further divided into a melter that melts the batch of glass stock mixture and a refiner in which clarification and homogenization of the glass melt exiting the melter takes place.

In the sheet glass manufacturing method of the present invention, in the melter while operating a burner while adding a stoichiometric amount of fuel material and a oxidant to a plurality of burners to melt the glass raw material mixture batch, the melter and At least one of the refiners is characterized in that the flow of oxidant separate from the operation of the burner.

In the present invention, the melter is a side port in which a port including a burner and an oxidant (ie, air or oxygen) inlet is disposed on both sides of the melter rather than an end port method in which a port is located near a batch inlet. ) Is preferred in view of controlling the redox ratio. As used herein, the term “port pair” refers to two ports located parallel to both sides of a side port melter.

The more excess oxygen in the melt-clarification section, the more the excess oxygen diffuses into the glass melt, and oxidation occurs to convert Fe ²⁺ into Fe ³⁺ in the glass melt. The lack of oxygen in the melt-clarification section is the reverse. Conventionally, as a method for making the inside of the melt-clarifying section into an oxidizing atmosphere, a method of injecting an excess amount of oxygen in a burner or a port located in the melter at the same time as the fuel is required for complete combustion at the same time as the burner is proposed. In practice, however, when fuel and air or excess oxygen are injected at the same time in the melter, energy efficiency is inevitably reduced, and thus additional fuel supply is needed to supply the heat required for melting the raw materials. In addition, in the side port method, fuel and oxygen are alternately supplied from side to side at a predetermined time interval from the left and right sides, and the burned gas is discharged to the opposite port, so that the excess oxygen remaining after the fuel is completely burned Easily vented out through the opposite port without contributing to the oxidizing atmosphere. Therefore, by putting the excessive amount of oxygen than the amount required for complete combustion with the burner or the fuel from the port at the same time the melt-system is to create within the refining zone to the oxidizing atmosphere is a significant disadvantage, and Fe ²⁺ in the glass in terms of energy efficiency to Fe ³⁺ There is a disadvantage that it does not oxidize effectively.

On the other hand, in the present invention, at least one of the melter and the refiner introduces an oxidant (i.e., oxygen or air) flow separate from the operation of the burner to effectively make the oxidizing atmosphere within the melt-clarification section.

Referring to the configuration of introducing an oxidant flow separate from the operation of the burner in the melter and / or refiner through embodiments of the present invention.

1 is a schematic view of one embodiment of a soda lime silicate glass manufacturing method according to the present invention. In the embodiment shown in Fig. 1, only the oxidant flow is introduced into the melter without operating the burner in at least one port (port pair in the case of the side port method) present in the melter. At this time, the remaining ports in the melter operate the burner while introducing a stoichiometric amount of oxidant to the fuel material and the fuel material.

This way, the oxidant, such as oxygen, introduced through the port where the burner is not running is not immediately affected by the combustion reaction, which does not reduce energy efficiency and does not easily escape out of the melt-clarification section, so that Fe ²⁺ present in the glass is Fe It can be effectively oxidized to ³⁺ . To achieve higher energy efficiency, the amount of uninjected fuel from the burner-free port is distributed to the burner-operated port located at the front of the melter and injected with oxygen close to complete combustion to melt the raw material. It is possible to achieve high energy efficiency while supplying enough heat for.

Figure 2 is a schematic diagram of another embodiment of the soda lime silicate glass manufacturing method according to the present invention. In the embodiment shown in FIG. 2, an oxidant (ie oxygen or air) flow separate from the operation of the burner is introduced into the refiner through a separate oxidant flow inlet present in the refiner. At this time, the ports present in the melter operate the burner while introducing a stoichiometric amount of oxidant to the fuel material and the fuel material.

In this way, since the oxidant flow is less influenced by the convection currents generated by a combustion of a fuel, the longer the time to visit the oxidant (e.g., oxygen) to the refiner, the Fe ²⁺ to Fe ³⁺ present in the glass Can be effectively oxidized. The reaction scheme in which Fe ²⁺ in the glass is oxidized to Fe ³⁺ by oxygen introduced into the refiner is as follows.

_{O 2 + 2FeO → 1 / 2O} 2 - + Fe 2 O 3

Figure 3 is a schematic diagram of another embodiment of the soda lime silicate glass manufacturing method according to the present invention. In the embodiment shown in FIG. 3, an oxidant (ie oxygen or air) flow separate from the operation of the burner is introduced into the melter through a separate oxidant flow inlet present in the melter. At this time, the ports present in the melter operate the burner while introducing a stoichiometric amount of oxidant to the fuel material and the fuel material.

In the present invention, the total amount of oxygen in the oxidant flow, which flows into at least one of the melter and the refiner, from the operation of the burner is at least 100 Nm ³ per hour on a volume basis (1 atm, gas fluid volume unit at 0 ° C.). desirable. If the total amount of oxygen in the oxidant flow is less than 100 Nm ³ per hour, it can be difficult to make the interior of the melt-clarification section a sufficient oxidizing atmosphere. In addition, to achieve higher energy efficiency, at least three pairs of burners in the melter are simultaneously supplied with a stoichiometric amount of oxidant (i.e., the equivalent of oxygen close to the complete combustion of the fuel and fuel) for the fuel substance and the fuel substance. desirable. For example, the volume ratio of air / fuel to atmospheric air is 10 to 15, the volume ratio of oxygen / fuel to oxygen is 2.0 to 2.9, and in the case of pure oxygen and air mixed gas, the oxygen in the mixed gas is based on the amount of oxygen in the mixed gas. It is preferable that the volume ratio of / fuel is 2.0-2.9. Fuel materials that can be used include fossil fuels such as LPG, LNG, and bunker seed oil (BC Oil), and the ratio that can achieve the highest efficiency in consideration of the type and condition of fossil fuels within the above ratio range is applicable. Can be.

The present invention relates to a method for continuously producing a plate-like soda lime silicate glass, in one embodiment of the present invention by floating the molten glass in a molten tin bath to form a plate. In another embodiment of the present invention, the molten glass is pressed into one or a plurality of rollers to form a plate. At this time, by using one or more rollers with irregularities, the molten glass can be formed into a plate-shaped glass having a pattern.

In short, the glass manufacturing method of the present invention, preferably, a batch in which the glass raw materials are mixed is introduced into a melting furnace in which a plurality of burners using fossil fuel as a heat source are disposed by the transfer means and melted / clarified ( Refining / Homogenization / Cooling and the like may be performed, and the molten glass may be discharged and then may be performed in a continuous melting furnace that is shaped into a plate by various molding methods as described above. In the plate-like soda-lime silicate glass manufacturing method of the present invention, process configurations or conditions other than those described above may be utilized as they are, or appropriately modified in the conventional soda-lime silicate plate glass manufacturing method, which is used in the art It is obvious to the skilled person.

According to another aspect of the present invention, it is prepared by the glass manufacturing method of the present invention as described above, 65 to 75 parts by weight of SiO ₂ , 0.1 to 3 parts by weight of Al ₂ O ₃ , Na ₂ O and 100 parts by weight of glass and A total of 10 to 18 parts by weight of K ₂ O, 5 to 15 parts by weight of CaO, 1 to 6 parts by weight of MgO, 0.01 to 0.5 parts by weight of SO ₃ and 0 to 0.013 parts by weight of total Fe ₂ O ₃ , and redox (Redox ) Soda lime silicate panes with a ratio of 0.05-0.24 are provided.

In the soda lime silicate glass of the present invention, when the total Fe ₂ O ₃ content exceeds 0.013 parts by weight per 100 parts by weight of glass, due to the reduction of visible light and solar radiation transmittance, the permeability is particularly suitable for use as solar cell cover glass and substrate glass. May not have The total Fe ₂ O ₃ content per 100 parts by weight of glass is more preferably 0 to 0.01 parts by weight, even more preferably 0 to 0.009 parts by weight.

In the soda lime silicate glass of the present invention, if the redox ratio is less than 0.05, it is difficult to perform the defoaming process by decomposition of SO _{3 in} the glass, and when it exceeds 0.24, especially the solar cell cover glass and the substrate glass due to the reduction of visible light and solar radiation transmittance. May not have adequate permeability for use. More preferable redox ratio is 0.1-0.2, More preferably, it is 0.12-0.2.

SiO ₂ in the soda lime silicate glass of the present invention serves as a network structure forming agent to form the basic structure of the glass, if the content is less than 65 parts by weight per 100 parts by weight of glass may cause problems in the durability of the glass, If it exceeds 75 parts by weight, there may be a problem of high temperature viscosity increase and meltability decrease. The SiO ₂ content per 100 parts by weight of glass is more preferably 68 to 72 parts by weight, even more preferably 70 to 72 parts by weight.

In the soda lime silicate glass of the present invention, Al ₂ O ₃ is a component that increases the high temperature viscosity of the glass and improves the durability of the glass when a small amount is added. If the content is less than 0.1 part by weight per 100 parts by weight of the glass, chemical resistance and water resistance This may be vulnerable, and if it exceeds 3 parts by weight, there may be a problem that the melt load increases with increasing high temperature viscosity. The Al ₂ O ₃ content per 100 parts by weight of glass is more preferably 0.5 to 2 parts by weight, even more preferably 0.7 to 1.2 parts by weight.

In the soda lime silicate glass of the present invention Na ₂ O and K ₂ O is a flux component that promotes the melting of the glass raw material, if the total of the two components is less than 10 parts by weight per 100 parts by weight of glass due to the increase in the occurrence of cosmetic melt Melt quality may occur, and if it exceeds 18 parts by weight, chemical resistance may occur. The sum of the contents of Na ₂ O and K ₂ O per 100 parts by weight of glass is more preferably 12 to 16 parts by weight, even more preferably 13 to 15 parts by weight.

CaO and MgO in the soda lime silicate glass of the present invention is a component that reinforces the weather resistance of the glass structure while helping to melt the raw material. If the CaO content is less than 5 parts by weight per 100 parts by weight of glass, durability degradation may occur, and if it exceeds 15 parts by weight, it may adversely affect product quality due to an increase in crystallization tendency. CaO per 100 parts by weight of glass The content is more preferably 7 to 12 parts by weight, even more preferably 8 to 11 parts by weight. In addition, in the case of MgO, if the content is less than 1 part by weight per glass part, the effect of reinforcing the weather resistance of the glass structure may be reduced while helping to melt the raw material. If the content exceeds 6 parts by weight, an increase in crystallization tendency causes an increase in crystal defects. Can be. MgO per 100 parts by weight of glass The content is more preferably 2 to 5 parts by weight, even more preferably 3 to 5 parts by weight.

In actual production, the forget-me-not (Na ₂ SO ₄ ) can be used to improve melt quality such as bubble removal, and the content remaining in the form of SO ₃ gas in the glass during the melting process remains at 0.01 to 0.5 parts by weight per 100 parts by weight of glass. It is common to do

In particular, the soda lime silicate glass of the present invention may contain other components in a small proportion (for example, 1% or less) and impurities which may be inevitably included in raw materials or manufacturing processes, for example, TiO ₂ , ZrO ₂ , F, Cl Etc. can be mentioned. However, as mentioned above, the soda lime silicate glass of the present invention does not intentionally include oxides such as Sb ₂ O ₃ , As ₂ O ₃ or CeO ₂ . More specifically, the soda lime silicate glass of the present invention is other than SiO ₂ , Al ₂ O ₃ , Na ₂ O, K ₂ O, CaO, MgO, SO ₃ , Fe ₂ O ₃ , TiO ₂ , ZrO ₂ , F and Cl All elements may be included in oxide form at less than 0.05 parts by weight per 100 parts by weight of glass. In addition, the soda lime silicate glass of the present invention is an oxide such as Sb ₂ O ₃ , As ₂ O ₃ and Ce, Sc, Y, La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Oxides of elements selected from Er, Tm, Yb, and Lu and oxides or metals such as CoO, CuO, NiO, Cr ₂ O ₃ , MnO ₂ , V ₂ O ₅ , Se, Ag, Cu, and the like are not intentionally included.

Since the soda lime silicate glass of the present invention exhibits very high visible light transmittance and solar radiation transmittance (for example, at least 91.2% visible light transmittance and at least 90.6% solar radiation transmittance based on 4mm thickness), the cover glass or the substrate of the solar cell It can be suitably used for building windows, exterior decoration of home appliances, flat mirror or parabolic mirrors for condensing, light diffusing devices of LCD type display devices, flat panel displays based on organic light emitting diodes or flat lamps. The soda lime silicate glass of the present invention may be coated with at least one transparent conductive thin film and / or low reflective thin film as needed.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited by these examples.

[Examples 1-3]

As a raw material, a batch containing feldspar, limestone, dolomite, soda ash and forget-me-not as a raw material is put into a continuous apparatus as described above, melted, and molded into a plate shape through a float method. The glass of the comparative examples was prepared. Bunker seed oil was used as fuel and general atmospheric air was used as an oxidant for combustion. There were a total of eight pairs of ports in the melter, and the burner operated ports were supplied with the stoichiometric ratio (fuel / bunker seed oil volume ratio = 12) required for complete combustion. However, in Comparative Example 3, excess air was injected from the stoichiometric ratio in the latter two pairs of ports. A separate inlet for oxygen-containing gas input was installed in the refiner. The amount of oxygen-containing gas added separately was maintained at 100 Nm ³ or more per hour based on the volume of oxygen in the gas.

Chemical composition analysis of the prepared glass was carried out using Rigaku's 3370 X-ray fluorescence spectrometer (XRF). The glass produced in each Example and Comparative Example had the composition and redox ratio shown in Table 1 below.

Table 1

About the produced glass plate, the optical characteristic was evaluated based on 4 mm thickness. Optical properties were measured as follows using Perkin Elmer's Lambda950.

Visible light transmittance (T-Vis): measured according to ISO9050: 2003 standard.

Solar radiation transmittance (T-Sol): measured according to ISO9050: 2003 standard. The solar radiation spectrum was based on AM1.5.

For the glass of each Example / Comparative Example, the total Fe ₂ O ₃ content, redox ratio, optical properties and characteristic process conditions are described in Table 2 (Example) and Table 3 (Comparative Example) below.

TABLE 2

TABLE 3

For the glass prepared in Examples 1 to 3, the total Fe ₂ O ₃ content range is 0.013 parts by weight or less, the redox ratio is 0.24 or less, at least 91.2% visible light transmittance and at least 90.6% solar radiation transmittance at 4 mm glass thickness. Indicated. In Examples 2 and 3, the sum of the amount of oxygen per hour inputted separately from the operation of the burner in the melt-clarification section was the same, but the redox ratio was lower in Example 3, and Example 3 provided a separate inlet to the refiner. In the case where the gas containing oxygen was installed and put in this way, it was estimated that the time for which the injected oxygen remained in the clarification section was longer, which was more effective in reducing the redox ratio.

Comparative Example 1 lowered the redox ratio by supplying oxygen through an inlet separate from the burner, but exhibited very low visible light and solar radiation transmittance due to excessive content of Fe ₂ O _3. It was not suitable to be used as substrate glass or the like. In Comparative Examples 2 and 3, although the total Fe ₂ O ₃ content was the level of Example, the results of applying the conventional manufacturing technique showed a very high redox ratio, and thus the visible light and the solar radiation transmittance were very low, and thus the solar cell cover glass and the substrate It was also unsuitable to be used for glass or the like.

Therefore, according to the present invention, the glass is prepared by introducing a separate oxidant flow from the operation of the burner in the melt-clarification section, but the total content of Fe ₂ O _{3 in} the prepared glass is 0 to 0.013 parts by weight per 100 parts by weight of glass. It was confirmed that the glass having high visible light and solar radiation transmittance at a level suitable for use as a solar cell cover glass and a substrate glass should be satisfied at the same time.

<Description of the code>

1: Port present in the melter (point in the tunnel shape: burner) in which only the oxidant flow is introduced into the melter without starting the burner.

2: Separate oxidant flow inlet in refiner

3: Separate oxidant flow inlet in melter

Claims (8)

1. A method for producing a batch of soda-lime silicate glass in a plate form by continuously passing a batch of glass raw material mixture through a melter and a refiner located downstream of the melter, followed by cooling and forming.

   The melter melts the batch of glass raw material mixture by operating a burner while introducing a stoichiometric amount of fuel material and a oxidant to the plurality of burners,

   At least one of the melter and the refiner is introduced with an oxidant flow separate from the operation of the burner,

   The total Fe ₂ O ₃ content of the prepared glass, characterized in that 0 to 0.013 parts by weight per 100 parts by weight of glass,

   Method for producing a plate-like soda lime silicate glass.
2. The method of claim 1, wherein a port including a burner and an oxidant inlet is present in the melter, and only the oxidant flow is introduced into the melter without operating the burner in at least one of the ports. .
3. The method of claim 1, wherein an oxidant flow separate from the operation of the burner is introduced into the refiner through a separate oxidant flow inlet present in the refiner.
4. The method of claim 1, wherein an oxidant flow separate from the operation of the burner is introduced into the melter through a separate oxidant flow inlet present in the melter.
5. The method of claim 1, wherein the total amount of oxygen in the oxidant flow separate from the operation of the burner, which flows into at least one of the melter and the refiner, is at least 100 Nm ³ per hour on a volume basis. .
6. Prepared by the method according to any one of claims 1 to 5, wherein 65 to 75 parts by weight of SiO ₂ , 0.1 to 3 parts by weight of Al ₂ O ₃ , Na ₂ O and K ₂ O per 100 parts by weight of glass. Soda with 10 to 18 parts by weight, CaO 5 to 15 parts by weight, MgO 1 to 6 parts by weight, SO ₃ 0.01 to 0.5 part by weight, and total Fe ₂ O ₃ 0 to 0.013 part by weight, and a redox ratio of 0.05 to 0.24. Lime silicate pane.
7. The soda lime silicate glass according to claim 6, wherein the soda lime silicate glass exhibits a visible light transmittance of 91.2% or more and a solar radiation transmittance of 90.6% or more on a 4 mm thickness basis.
8. The method of claim 6, wherein the cover glass or the substrate of the solar cell, the window of the building, the exterior decoration of the home appliances, the mirror of the flat mirror or condensed light, the light diffusing device of the LCD type display device, the organic light emitting diode-based flat panel display Or a soda lime silicate glass for flat plate lamps.

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