JP2009132595A - Refractory material for glass production, method for producing the same, glass melting furnace, and method for producing glass article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dense, highly heat-resistant refractory material for glass production having performance suitable upon molding a high precision thin sheet glass used for various electronic components, and particularly usable upon molding sheet glass suitable as a cover glass for solid image sensors such as a CCD (charge coupled device) and an CMOS (complementary metal-oxide semiconductor), to provide a method for producing the refractory material for glass production, to provide a glass melting furnace using the refractory material for glass production, and to provide a method for producing a glass article using the refractory material. <P>SOLUTION: Disclosed is a refractory material for glass production obtained by sintering inorganic oxide particles, wherein an α ray release amount is ≤1.0c/cm<SP>2</SP>hr. Also disclosed is a method for producing the refractory material for glass production comprising: a working stage where an Si-containing raw material and/or a Zr-containing raw material having an α ray release amount of ≤1.0 c/cm<SP>2</SP>hr is pulverized and mixed; and a firing stage where the obtained pulverized matter is fired at a firing temperature of ≥1,200°C. In the method for producing the glass article, the glass article is produced using a glass melting furnace where the refractory material for glass production is arranged at the furnace wall in contact with molten glass. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refractory material that is a structural material for glass production, and particularly used when producing glass used for packages such as CCD and CMOS, TFT liquid crystal display devices and the like that house electronic circuits such as optical semiconductors. Related to refractory materials.

  Refractory materials used in glass melting furnaces used when manufacturing glass articles by heating inorganic raw materials to high temperatures have heat resistance, high temperature strength, excellent spalling resistance, difficult reaction with molten glass Many performances such as sex are required. For this reason, such a refractory material is one of the members indispensable for producing high-quality glass articles in the glass manufacturing industry. As a glass production method, many new production methods such as a sol-gel method and a vapor phase growth method have been invented so far, and a new technique related thereto has been developed and presented. However, many of the major glass products that exhibit precise shapes and various performances are still obtained by hot forming the molten glass into a predetermined shape, so the molten glass is melted homogeneously. The importance of refractory materials used in glass melting furnaces remains unchanged today. And there is no doubt that such basic technology is the foundation of glass technology that supports various science and technology such as the electronics industry.

  For this reason, many inventions have been made so far with regard to technologies relating to refractory materials. For example, Patent Document 1 discloses an invention in which corrosion of a refractory material caused by molten glass can be improved by limiting the size and content of dendritic zirconia crystals in an AZS refractory. . Further, in Patent Document 2, when producing high-purity fused silica glass, a plurality of vent passages are formed as paths for releasing gas on the surface that comes into contact with the glass on the inner surface of the refractory material such as graphite, BN, or SiC. Invented that this can be achieved. Further, in Patent Document 3, as an oxidant having an oxidizing action at high or low temperatures in a refractory, in order to solve the problem of leaching of the matrix glass, which becomes a problem when using an alumina, silica, zirconia refractory, An invention is disclosed in which tin oxide, cerium oxide, manganese oxide, antimony oxide and arsenic oxide are added for high temperatures, and sodium nitrate or sodium sulfate is used for low temperatures.

  In addition, image display devices, which have become one of the key products in today's electronics industry, will continue to be developed more and more in the future along the two trends of increasing size and thickness. Although it is thought that it is a thing, the further severe request | requirement is calculated | required also by the plate glass mounted there, As a result, various invention is disclosed. For example, Patent Document 4 discloses an invention in which a refractory molded body used in an overflow molding apparatus can be formed into a specific shape to cope with the molding of a large-area plate glass. Further, in Patent Document 5, it is possible to easily form even a complicated shape having a through hole in the longitudinal direction, for example, by forming a refractory molded body used for forming a sheet glass by casting. An invention to be disclosed is disclosed.

On the other hand, high-precision plate glass is used not only for image display devices but also for thin plate glass mounted on solid-state imaging devices such as CCDs and CMOSs, which are also called electronic eyes. What is required of the cover glass of these optical semiconductor elements is high homogeneity, visible light transmittance, weather resistance, hardness, and the like, and one of the required performances is a low α-ray emission amount. Therefore, many inventions in this field have been made. For example, Patent Document 6 discloses the glass composition range of a cover glass for a solid-state imaging device having a composition that reduces α rays.
JP 2001-220249 A JP 2007-077014 A Japanese Patent Laid-Open No. 10-072264 JP 2007-112684 A JP 2007-197303 A JP 2005-126320 A

  However, the inventions made so far are not sufficient to realize the glass forming required for various uses at a sufficiently satisfactory level. For example, even if it is limited to the use of sheet glass used in the electronics industry, not only liquid crystal display devices and plasma displays but also thin glass sheets and LED element cover glasses mounted on solid-state image sensors such as CCDs and CMOSs, which are also called electronic eyes Furthermore, there is a thin glass having various functions such as an optical filter. Many of such thin glass plates are not manufactured by a downdraw molding method, and are generally produced by melting in a pot made of a heat-resistant alloy made of a platinum group element, or constructed by a synthetic quartz block. Manufactured in a small melting furnace. However, these manufacturing methods have many problems. For example, when using a pot made of a platinum group element, it is not economical because it must have a certain wall thickness in order to prevent deformation at high temperature, while the platinum group element generated by corrosion of the platinum group element It has been pointed out that it is extremely difficult to prevent these fine particles from being mixed into the molten glass. In addition, in the case of a small furnace made of synthetic quartz block, the wall surface is easily eroded depending on the composition of the glass to be melted, and it tends to cause abnormal expansion due to the phase transition phenomenon depending on the operating temperature and atmosphere. It has also been pointed out that serious damage such as peeling and peeling occurs. In addition to these refractories, many refractories are known, but all have problems in terms of erosion, high-temperature strength, and various impurity contents, which are extremely high requirements in the electronics industry. In order to produce high-quality glass products, it is necessary to manufacture a number of defects with the preparedness and identify and sort non-defective products through high-level inspection.

  Moreover, about the refractory molded object used in order to shape | mold thin plate glass, such as a cover glass of a solid-state image sensor, even if it is what comprised a glass composition with the high purity raw material as it exists in patent document 6, If the amount of impurities contained is not sufficiently controlled, there is a risk that the molded glass sheet will be judged defective due to impurities mixed during melting and molding. Was also sought.

  In view of such circumstances, the present invention exhibits suitable performance when manufacturing not only large-area plate glass but also high-precision and high-performance thin plate glass used for various electronic components and the like. A dense and highly heat-resistant glass fire-resistant material used when producing a glass plate suitable as a cover glass for a solid-state imaging device, a method for producing the glass fire-resistant material, and a glass fire-resistant material. A method for producing a glass article using a glass melting furnace using glass and a refractory material for glass production is provided.

  The inventors of the present invention have studied various molding methods employed to realize the required high-definition outer dimensions of thin glass used as a cover glass of a solid-state imaging device such as a CCD or CMOS. In the process, the same overflow down-draw molding method was found to be used for molding large-area plate glass for liquid crystal display devices, etc. as a molding method that is economically and dimensional accurate. . However, when the glass sheet used for the image sensor cover glass is formed by a downdraw molding device, the trace amount of radioactive impurities contained in the refractory material such as refractory used in this device is mixed into the molten glass. In some cases, the measured value of the α-ray emission amount of the formed sheet glass increases. If the α-ray emission amount of the plate glass exceeds the control limit value due to such a phenomenon, even if a plate glass having a highly accurate surface quality is formed, it cannot be made a good product. In view of this, the researchers have conducted research to reduce the amount of alpha rays emitted from sheet glass based on such a viewpoint, and limited the amount of impurities in the refractory molded body used in the overflow downdraw molding apparatus. Finds that plate glass used in applications where there is a high need to reduce the amount of radiation generated as a cover glass of a solid-state image sensor can be manufactured continuously over a long period of time with a stable quality. Is provided here.

That is, the refractory material for glass production of the present invention is a refractory material obtained by sintering two or more kinds of inorganic oxide particles, and the α ray emission amount is 1.0 c / cm ² · hr or less. Features.

Here, the point that the α-ray emission amount is 1.0 c / cm ² · hr or less, which is a refractory material obtained by sintering two or more kinds of inorganic oxide particles, will be described. The refractory material obtained by sintering two or more kinds of inorganic oxide particles is a state in which the surfaces of the powder particles made of two or more different kinds of inorganic oxides are in contact with each other instead of only one kind of inorganic oxide particles. By firing at a high temperature while holding at a high temperature, one or more new crystal phases are formed by a solid phase reaction or a liquid phase reaction between the respective particles so as to minimize the interfacial free energy between the inorganic oxide particles. It is a refractory material that is newly formed as a constituent phase or is formed by fusing or joining two or more particles. Further, that the α-ray emission amount is 1.0 c / cm ² · hr or less, the radioactive equivalent to a natural radioactive decay series (uranium series, thorium series or actinium series) contained in a trace amount in the refractory This means that the amount of α rays emitted from the refractory and originating from the substance is constantly 1.0 c or less per unit square cm per unit time.

And, it is not composed of only one kind of inorganic oxide particles, for example, when it represents individual oxides such as SiO ₂ and ZrO _2, it is not composed of only SiO ₂ particles or only ZrO ₂ particles. In the case where SiO ₂ particles, SiO ₂ particles, and ZrO ₂ particles coexist, it corresponds to two or more types. In addition, after forming a single synthetic phase by calcining or sintering individual oxide particles and then obtaining a refractory by sintering the synthetic phase, for example, high temperature of SiO ₂ particles and ZrO ₂ particles In the present invention, in the case where the zircon (ZrO ₂ · SiO ₂ ) particles are synthesized by reaction and then composed of oxides containing two or more cations such as bonding the zircon particles at high temperature, It expresses that it consists of the above oxide particles.

  Even if there are two or more kinds of inorganic oxide particles, if a refractory having a composition composed of a large number of oxides is used, the risk of containing radioactive elements with large amounts of impurities and α-ray emission increases. It is not preferable to use an oxide that is difficult to manage. In view of the above, it is more preferable that the refractory is sintered of 2 to 6 inorganic oxide particles, and more preferably 2 to 4 inorganic oxide particles are sintered. More preferably, it is a sintered refractory of 2 to 3 types of inorganic oxide particles, and most preferably only 2 types of inorganic oxide particles are sintered. Refractory material. However, in the present invention, the number of types of inorganic oxide particles such as one type, two types, and the like can be counted at least in a composition of refractory having a content of 1% by mass or more.

Refractories constructed by sintering inorganic oxide particles. When the amount of α-ray emission exceeds 1.0 c / cm ² · hr, refractories are used for a long time at the interface that contacts molten glass. When the refractory is gradually eluted in the molten glass, impurities in the refractory are also eluted, and as a result, the content of radioactive elements in the glass is increased, and the molten glass is formed as a glass article. This is not preferable because the amount of emitted α-rays after the process becomes a high value and the glass article cannot be determined as a non-defective product.

  For inorganic oxide particles, the strength of the compact after sintering is sufficiently high, there is no hindrance to the reactivity with the molten glass, and there is no problem with performance such as creep properties and spalling properties at high temperatures. Any thing can be used.

Regarding the measurement of the α ray emission amount of the refractory material for glass production according to the present invention, for example, using a measuring device such as a 2π-type gas flow proportional counter, PR-10 gas (mixed gas of 90% argon and 10% methane) ) The measurement limit is higher than 0.002 c / cm ² · hr by carrying out continuous measurement for 2 days using a measuring device having an electrode aperture area of 4000 cm ² under flow. What was measured by the state, or what was obtained by the apparatus or method which can be measured with the precision equivalent to it should just be used.

  In addition to the above, the refractory material for glass production of the present invention has an α-ray emission amount of a refractory formed by sintering if the U and Th contents of the inorganic oxide particles are each 1 ppm or less. As a result, even if U and Th are eluted from the refractory into the molten glass, the amount will not exceed the allowable range, so it will not be released from the glass article. The α dose is also within a predetermined range, which is preferable because a stable glass article can be obtained.

  Here, the contents of U and Th of the inorganic oxide particles are each 1 ppm or less means that the content of uranium or thorium with respect to the refractory for glass production is 0.0001% or less in terms of mass percentage. is doing.

  As a quantitative analysis method for identifying the contents of U and Th in the refractory, ICP emission spectroscopy or the like may be used.

In addition to the above, the refractory material for glass production of the present invention has a composition in which the composition of the molten glass is expressed as a percentage by mass in terms of oxide as long as the structure does not substantially contain Al ₂ O ₃ as an inorganic oxide. In the case where the Al ₂ O ₃ is used in contact with an aluminoborosilicate glass containing 3% or more, the refractory having high corrosion resistance on the surface of the refractory when held at a high temperature of 1000 ° C. or higher. This is preferable because the refractory can be used continuously over a long period of time. Here, “substantially not containing Al ₂ O ₃ as an inorganic oxide” means that the content does not exceed 1% in terms of oxide-based mass percentage. That is, for example, an AZS refractory or a refractory baked from a clay (clay) raw material, such as an refractory containing Al ₂ O ₃ , the composition of the molten glass is expressed in mass percentage in terms of oxide, and Al ₂ O ₃ is When used in applications that come into contact with aluminoborosilicate glass containing 3% or more, the refractory will be eroded over time, especially for down-draw molding equipment that needs to realize a precise dimensional shape. It is not preferable as a refractory to be mounted. Therefore, it is preferable that the refractory for glass production of the present invention is a refractory made of alumina-free inorganic oxide particles substantially not containing Al ₂ O ₃ .

As the aluminoborosilicate glass in which the composition of the molten glass is expressed in terms of mass percentage in terms of oxide and contains 3% or more of Al ₂ O ₃ , for example, SiO ₂ 55 to 69% and Al ₂ O _{3 3 to} 16% in terms of mass%. _{, B 2 O 3 7~20%,} 0~5% MgO, CaO 0~10%, BaO 0~12%, SrO 0~10%, CaO + BaO + SrO + a glass composition corresponds to a composition of ZnO from 0.3 to 13% To do.

In addition to the above, the refractory material for glass production of the present invention contains one or more of SiO ₂ and ZrO ₂ in addition to the inorganic oxide, each of which is expressed as a mass percentage in terms of oxide, and is 20% to 80%. As long as it is contained within the above range, stable and high performance in terms of corrosion resistance at a high temperature state of 1000 ° C. or higher for a molten glass having a composition such as silicate glass, borosilicate glass, or aluminosilicate glass. Will be demonstrated.

Here, the inorganic oxide contains at least one of SiO ₂ and ZrO ₂ , each of which is contained in a range of 20% to 80% in terms of mass percentage in terms of oxide. by displaying the composition of the refractory inorganic oxide conversion, when expressed the composition as _SiO 2, ZrO _2, SiO ₂ or ZrO ₂ Kano any of inorganic oxide represented by mass% 20 % Is in the range of 80%.

When the composition of the refractory material for glass production is less than 20% in terms of the oxide-based mass percentage for both SiO ₂ and ZrO ₂ , it is used for beam materials and columnar materials, for example, overflow molding equipment. When used as a structural material having a long structure such as a molded product made of refractory, desired creep properties are difficult to obtain, and long-term use becomes difficult. Further, such a composition is not preferable because the erodibility to the molten glass may increase. On the other hand, the composition of the refractory for glass production cannot exceed 80% in terms of the oxide-based mass percentage for either SiO ₂ or ZrO ₂ , but one of SiO ₂ and ZrO ₂ is 20%. If the other is less than 80% and the other exceeds 80%, even if there is no problem with respect to heat resistance and erosion, there may be a problem with thermal shock resistance, which is not preferable.

In addition to the above, the refractory material for glass production of the present invention is a dense and heat-resistant structure if the inorganic oxide is made of zircon (ZrO ₂ · SiO ₂ ). It is suitable for application to the production of high-performance glass articles.

Here, the inorganic oxide made of zircon (ZrO ₂ · SiO ₂ ) means that it is not natural zircon but synthetic zircon artificially synthesized from high-purity SiO ₂ raw material and ZrO ₂ raw material. It is. Since natural zircon has a high content of U and Th, it cannot be applied in the present invention.

  In addition, it is important that the refractory material for glass production made of synthetic zircon has sufficient creep properties and spalling properties while being kept at a heat resistance of 950 ° C. or higher, ie, 950 ° C. or higher. For this purpose, the refractory must have a sufficiently dense structure.

  In addition to the above, the refractory material for glass production of the present invention contains a sintering aid in the range of 0.01% to 10% in terms of oxide-based mass percentage. A dense refractory with stable strength in addition to high heat resistance, which can form a structure that cannot be realized only by sintering only the inorganic oxide that is the main component of the refractory Can be obtained.

Here, when the sintering aid is contained in the range of 0.01% to 10% in terms of mass percentage in terms of oxide, the composition of the refractory is expressed in terms of inorganic oxide. This means that the content ratio of the sintering aid is 0.01%, that is, within the range of 100 ppm to 10%. Sintering aids are added so that the sintering of inorganic oxides, which are the main components when producing refractories for glass production, is made into a homogeneous and dense structure, and that it is reproducibly realized at low temperatures. In the present invention, it is particularly preferable to add at least one of an oxide of a transition metal element, a divalent metal oxide, and a tetravalent metal oxide. In the present invention, a more preferable sintering aid is preferably any one of ZnO, Fe ₂ O ₃ , CuO, TiO ₂ , SnO, and MgO. That is, it is preferable that any one or more of ZnO, Fe ₂ O ₃ , CuO, TiO ₂ , SnO, or MgO is contained in the range of 0.01% to 10% in terms of the oxide-based mass percentage display. It is.

If one or more of the sintering aids of ZnO, Fe ₂ O ₃ , CuO, TiO ₂ , SnO or MgO is less than 0.01% in terms of the oxide-based mass percentage, This is not preferable because it does not sufficiently function as an agent, and as a result, densification of the refractory for glass production is hindered or the strength becomes insufficient. When one or more of the sintering aids of ZnO, Fe ₂ O ₃ , CuO, TiO ₂ , SnO or MgO has a content exceeding 10% in terms of the oxide-based mass percentage display, This is not preferable because the erosion of the resin may decrease. From the above viewpoints, it is more preferable that any one or more sintering aids of ZnO, Fe ₂ O ₃ , CuO, TiO ₂ , SnO, or MgO are in a total amount of 0. It is contained in the range of 1% to 8%, and more preferably, the sintering aid is contained in the range of 1% to 7% in terms of the oxide-converted mass percentage display. It is.

  Although the detailed function of these sintering aids is unclear, the present inventors have found that these sintering aids cause eutectic phenomena at the interface with inorganic oxides that do not easily form a liquid phase. Therefore, it is presumed to have a function of promoting the mass transfer between the main components constituting the inorganic oxide.

  In addition to the above, the refractory material for glass production according to the present invention is a material that includes a refractory noble metal-containing layered material on the surface of the refractory material in contact with the molten glass. In addition, the surface of the refractory material is hardly deteriorated, and a stable quality glass article can be produced without maintenance for a long period of time.

  A fireproof noble metal-containing layered material disposed on the surface of a refractory material in contact with the molten glass means that the surface of the refractory material in contact with the molten glass constitutes a refractory noble metal such as platinum. It means that the structural material containing an arbitrary amount of group elements (platinum, iridium, osmium, palladium, rhodium and ruthenium) has a layered structure, that is, a sheet-like structure. The refractory noble metal-containing layered material may contain a heat-resistant material such as ceramics or other metal material, or may be a metal material made of a platinum group element.

  The structure of the refractory noble metal-containing layered material is not particularly limited as long as it exhibits desired performance. That is, it may contain a predetermined form of a refractory noble metal material such as granular, powder, film or fiber, or may be composed only of a refractory noble metal material such as a solid solution.

  In addition to the above, the refractory material for glass production of the present invention is sufficiently economical even if it is a refractory material for glass production having a large volume, provided that the refractory noble metal-containing layered material has a thickness of less than 1 mm. Therefore, it is possible to efficiently produce a glass article of excellent quality over a long period of time under a condition where the cost is suppressed.

  The refractory noble metal-containing layered material has a thickness of less than 1 mm because the thickness of the structural portion arranged in a sheet shape containing the heat-resistant noble metal composed of the platinum group element is less than 1 mm. However, this indicates that the layered material covers the portion that is in contact with the molten glass.

  Moreover, if the refractory material for glass manufacture of this invention is a wall material mounted in a downdraw molding apparatus in addition to the above, it is a long glass article, ie, downdraw directions, such as tube glass, plate glass, glass fiber, etc. It is preferable because a glass article having a long shape can be molded in a high-precision state with high-precision dimensions and can be applied to glass articles used in various applications. .

  Here, the downdraw molding apparatus refers to various glass molding apparatuses such as an overflow downdraw molding apparatus, a slit downdraw molding apparatus, a roll-out downdraw molding apparatus, a bushing apparatus, and a downdraw apparatus that applies the Milo method. is there.

  The refractory material for glass production of the present invention has, in addition to the above, a bowl-shaped molten glass supply groove having an opening at the top, the tops of both side walls of the glass supply groove as overflow weirs, and the outer surfaces of the side walls. If the part is a refractory that forms a molded body in which the outer surfaces of both side walls are close to each other so that the cross-section is substantially wedge-shaped and is terminated at the lower end, the translucent surface of the molded sheet glass Is formed as a sheet glass with a free surface, it is difficult to form surface defects, and it is easy to form a sheet glass having high dimensional accuracy.

  It has a bowl-shaped molten glass supply groove with an open top at the top, the top of both side walls of this glass supply groove is used as an overflow weir, and the outer surface of both side walls has a substantially wedge-shaped cross section. It is as follows that it is the refractory which comprises the molded object which made them mutually approach toward the downward direction, and was terminated at the lower end. That is, the shape of the cross section perpendicular to the longitudinal direction has a substantially wedge shape, and is a molded body having a flange for allowing molten glass to flow after melting in a glass melting furnace at the upper portion of the wedge shape. The molten glass is allowed to flow down from the flange portion to the wedge-shaped inclined surface and merged at the lower end to form a single sheet glass.

  The overflow downdraw molding apparatus has a configuration in which the refractory material for glass production of the present invention is used in molding a glass article and is incorporated in the apparatus as a molded body having heat resistance against molten glass. As the external dimensions of the refractory molded body mounted on such an overflow downdraw apparatus, it is possible to have a shape with a width of 50 mm to 500 mm, a height of 300 mm to 3000 mm, and a length of 20 mm to 5000 mm. Such a refractory molded body does not necessarily need to be an integral molded body, and may be a combination of a plurality of members. For example, in order to improve the strength of the refractory molded body, it may have a structure in which an opening hole is provided in the longitudinal direction of the molded body and a core material is inserted, and an auxiliary material that locally supports the molded body is provided. It may be.

The method for producing a refractory material for glass production according to the present invention includes a processing step of pulverizing and mixing a Si-containing raw material and / or a Zr-containing raw material having an α-ray emission amount of 1.0 c / cm ² · hr or less, and the obtained pulverization And a firing step of firing the product at a firing temperature of 1200 ° C. or higher.

Here, a processing step of pulverizing and mixing a Si-containing raw material and / or a Zr-containing raw material having an α-ray emission amount of 1.0 c / cm ² · hr or less, and the obtained pulverized product is fired at a firing temperature of 1200 ° C. or higher. Having a firing step is as follows. That is, the α-ray emission amount is measured in advance, the Si-containing raw material and the Zr-containing raw material whose value is 1.0 c / cm ² · hr or less are pulverized using a pulverizer or simultaneously, and further a mixing device is used. Through a sintering process in which the mixed raw material powder obtained by this processing process is sintered by sintering to a temperature of 1200 ° C. or higher after being dry-type or wet-molded, After cooling, a refractory material for glass production having a predetermined size and shape can be obtained, and after the pulverized product obtained by the processing step is temporarily formed into a predetermined shape, the pulverized product is obtained by the firing step. It means that the production method is such that it is fired so that it can be sintered at a high temperature. Further, in the present invention, the performance of the refractory becomes more stable as the amount of α-ray emission is reduced. Therefore, both the Si-containing material and the Zr-containing material are 1.0 c / cm ² · hr or less. More preferably, the total amount of the α-ray emission amount of the Si-containing raw material and the Zr-containing raw material is preferably 1.0 c / cm ² · hr or less.

  About a processing process, grinding | pulverization and mixing may be performed with another apparatus, or may be performed with the same apparatus. However, if importance is attached to the contamination and contamination of various impurities from the pulverization and mixing apparatuses, it is more preferable that the pulverization and mixing be performed simultaneously in one apparatus. However, any device is not limited as long as sufficient cleanliness can be realized.

  As for the pulverization, either dry pulverization or wet pulverization may be used as long as efficient pulverization can be performed even if various pulverization apparatuses are used. An additive such as a grinding aid may be used at the time of grinding. However, if the material to be ground is not water-soluble, wet grinding is preferable because efficient grinding is possible.

  For example, in dry grinding, the atmosphere may be air, helium, neon, argon, krypton xenon, fluorine, chlorine, bromine, knox (NOx), sox (SOx), nitrogen, carbon monoxide, carbon dioxide, hydrogen, chlorine, water vapor or A mixed atmosphere of these gases may be employed. In wet pulverization, water, hydrogen peroxide solution, an aqueous solution containing a surfactant, an aqueous solution having a reactive component in a state where some or all of the raw material is dissociated into ions, such as salt, an acid solution It is possible to use an appropriate amount of liquid such as alkaline solution, ion-activated water, plasma irradiation water, various gas saturated water such as carbon dioxide saturated water, nonpolar organic solvent, polar organic solvent and the like.

  The crusher includes a jaw crusher, a compression crusher including a cone crusher, a shear crusher including a cutter mill, an impact crusher including a hammer crusher, a centrifugal roller mill, and a roller mill (or a roller rolling mill) including a bawl mill. .), High-speed rotating mills (also called impact shearing mills) including hammer mills, pin mills, turbo mills and supermicron mills, container-driven media including rolling ball mills (narrowly defined ball mills), vibrating ball mills, medium planetary mills, etc. A pulverizer such as a mill (ball mill in a broad sense) or an airflow pulverizer can be used.

  In addition, various types of mixing devices may be used for the mixing as long as they can be mixed under conditions that allow homogeneous mixing in which segregation does not easily occur. There is no need for one mixing device, and a plurality of methods may be combined as necessary. The mixing apparatus may also be mixed under various atmospheres as in the above-described pulverizing apparatus, and may be further mixed with various solvents added.

  The simplest and most economically efficient mixing device may be one having a performance that also serves as a grinding device such as a ball mill. This ball mill uses ceramics or natural ore as a medium for mixing and grinding called balls, and gradually crushes and crushes the material to be crushed by repeatedly colliding the media with the surface of the material to be crushed. It is. This equipment includes rolling ball mills (narrowly defined ball mills) that perform grinding in the most common cylindrical or conical containers, vibration mills that perform fine grinding by applying fine vibrations to the balls, or balls It also includes a medium planetary mill and the like in which acceleration is given to improve the grinding efficiency. When using a ball mill, measure the amount of alpha rays emitted from the ball material used and its inner wall material in advance, or measure the amount of alpha rays emitted due to crushing, and exercise sufficient caution. There is a need.

  In addition to the above, the method for producing a refractory material for glass production according to the present invention includes a casting step in which the pulverized raw material obtained in the processing step is mixed with water or an organic solvent, and then the powder-liquid mixture is poured into the mold. If it is a thing, even if it is a refractory material of a complicated shape, since the molded object which becomes a precise | minute structure is obtained, it is preferable.

  As a method for preparing the powder / liquid mixture, any method capable of performing homogeneous mixing may be used. Appropriate conditions may be selected for various conditions such as the mixing ratio of the raw pulverized product and water or an organic solvent, pH, and temperature. In addition, a dispersant, a viscosity adjuster, a pH adjuster, an antifreeze agent, an antioxidant, a surface coating agent, a defoaming agent, or the like may be appropriately used to adjust the state of the powder / liquid mixture.

  Moreover, as a mold for performing casting, any material may be used as long as it can perform proper casting. Also, the thickness and structure of the frame are not particularly limited. For example, a gypsum frame that absorbs the solvent with time may be used as the frame, and other porous materials and water-absorbing materials may be used. Furthermore, a mechanism for compensating for expansion and contraction of the frame can be provided at a predetermined location.

In addition to the above, the method for producing a refractory material for glass production according to the present invention is highly dense by firing if the average particle size D ₅₀ of the pulverized raw material obtained in the processing step is in the range of 1 μm to 60 μm. A refractory molded article can be obtained, and a refractory molded article exhibiting stable strength that can be used for a long period of time can be obtained. The average particle diameter D ₅₀ of the pulverized material, when used in grinding a plurality of raw materials individually an average particle diameter D ₅₀ of the particle size of each raw material, when crushed while mixing at a time those of the average particle diameter D ₅₀ of the pulverized material at the mixed state.

The average particle diameter D ₅₀ of the raw material pulverized material obtained in the processing step is in the range of 1 μm to 60 μm. It represents that D ₅₀ which is an effective particle diameter in the product curve is 1 μm or more and 60 μm or less.

To measure the average particle diameter D ₅₀ may be, for example, using a particle size measuring apparatus such as a calibrated laser diffraction particle size distribution measuring apparatus.

Regarding the improvement in performance required for use of the molded product, although the average particle size D ₅₀ of the pulverized product obtained in the processing step is less than 1 μm, much time and labor are required to make the pulverized particles fine. , So much improvement is difficult to recognize. The average particle diameter D ₅₀ of the pulverized material exceeds 60 [mu] m, if the densification during sintering is insufficient occur, resulting sufficiently unfavorably occur even if a molded article having high strength can not be obtained.

In the present invention, if the average particle diameter D ₅₀ of the pulverized product is in the range of 1 μm to 60 μm, it is manufactured in addition to making it possible to suppress the radiation amount of the α-rays described above. Since the structure of the refractory can be in a dense state, other physicochemical performance such as high-temperature strength can be added to the refractory.

Above average particle diameter D ₅₀ of the raw material pulverized material from the viewpoint obtained in the processing step, such as, more preferably in a range from 5μm to 50 [mu] m.

  The glass melting furnace of the present invention is characterized in that the refractory material for glass production of the present invention is disposed as a furnace wall material in contact with the inorganic multi-component molten glass.

Here, the refractory material for glass production of the present invention is arranged as a furnace wall material in contact with the inorganic multi-component molten glass as follows. That is, a sintered refractory material of inorganic oxide particles having an α-ray emission amount of 1.0 c / cm ² · hr or less, or in addition, U, Th of inorganic oxide particles. Refractories for glass production each having a content of 1 ppm or less, and in addition, in addition to inorganic oxides, any one or more of SiO ₂ and ZrO ₂ is 20% to 80% in terms of mass percentage in terms of oxide. Refractories for glass, which are contained within the range of refractory for glass, in addition, a sintering auxiliaries, contained in the range of 0.01% to 10% in terms of oxide-based mass percentage, or In addition, a refractory material for glass production in which the total content of U and Th up to 10 mm from the surface in contact with the inorganic molten glass at 1000 ° C. or higher is 5 ppm / mm ² or less, and in addition, downdraw molding apparatus Used for manufacturing various glass articles such as plate glass, tube glass, hot-pressed products, etc. It means that it is a glass melting furnace.

  The wall surface in contact with the molten glass is a variety of materials such as a melting tank, a clarification tank, a melting pot, a throat, or a melting chamber that are used to retain and flow the glass raw material when it is in a molten state when heated. Is a part of a partial tank of a glass melting furnace that has various functions, and is used for partitioning with a dense wall surface that requires high temperature heat resistance and shielding properties. In addition, all the dense partition surfaces of the glass melting furnace such as a side wall surface, a floor surface, and a ceiling surface are represented.

  The method for producing a glass article of the present invention is to homogenize a molten glass using the glass melting furnace of the present invention, hot-mold the homogenized molten glass, and perform a slow cooling operation after hot forming. Features.

  Here, using the glass melting furnace of the present invention, the molten glass is homogenized, the homogenized molten glass is hot-formed, and after the hot forming, the slow cooling operation is performed. The material is homogenized by clarifying and stirring the molten glass in a glass melting furnace arranged as a furnace wall material in contact with the molten glass, and finally forming the glass article by annealing the formed glass. I mean.

  Moreover, the manufacturing method of the glass article of this invention is characterized by carrying out the overflow molding of molten glass using the refractory material of this invention as a molded object.

  Here, overflow molding of molten glass using the refractory material of the present invention as a molded body has a bowl-shaped molten glass supply groove opened at the top, and the tops of both side walls of the glass supply groove are overflow weirs. And, using the refractory material constituting the molded body, which is made close to the outer surfaces of the both side walls facing downward so that the outer surface portions of the both side walls have a substantially wedge-shaped cross section, are terminated as the molded body, This means that the homogenized molten glass is overflow molded.

  Moreover, it is preferable to manufacture the manufacturing method of the glass article of this invention, managing the dimension shape of the plate glass shape | molded, and the flow volume of molten glass. And as a means for this management, what is necessary is just to adjust the drawing speed of plate glass, and adjustment of the cooling conditions of plate glass.

  The refractory material for glass production of the present invention, the method for producing the refractory material for glass production, and the method for producing a glass article have the following effects.

(1) The refractory material for glass production of the present invention is a refractory material obtained by sintering two or more kinds of inorganic oxide particles, and the α ray emission amount is 1.0 c / cm ² · hr or less. In particular, when manufacturing plate glass suitable as a cover glass for solid-state imaging devices such as CCDs and CMOSs, it is possible to reduce the increase in the amount of α-ray generation in the plate glass due to substances that cause α-rays entering the plate glass. It is easy to manufacture the glass article in the state where it is made.

  (2) In the refractory material for glass production of the present invention, if the U and Th contents of the inorganic oxide particles are each 1 ppm or less, the contents of U and Th that require special attention as α-ray emitting substances Since it is suppressed, it is easy to obtain glass articles such as plate glass of a quality in which U and Th are hardly mixed in the glass and the α-ray emission amount is constantly maintained at a low level.

(3) Further, in the refractory material for glass production of the present invention, the inorganic oxide contains one or more of SiO ₂ and ZrO ₂ , each of which is expressed as a mass percentage in terms of oxide, and is 20% to 80%. If it is contained within the range, in addition to the effect of reducing the amount of α-ray generation described above, it becomes a refractory having a dense structure with high heat resistance and mechanical strength, and also creep and spalling properties. It is preferable as a refractory material for glass production used in applications that need to be heated to a high temperature of 1200 ° C. or higher.

  (4) Moreover, if the refractory material for glass manufacture of this invention contains a sintering auxiliary agent in the range of 0.01 to 10% by the mass percentage display of oxide conversion, it will be mentioned above α In addition to the effect of reducing the amount of generated wire and improvement of various mechanical performances in high temperature range, it can constitute a highly dense refractory, and has high corrosion resistance when in contact with molten glass that is melted at high temperature. It will be demonstrated.

  (5) Moreover, if the refractory material for glass manufacture of this invention arrange | positions a refractory noble metal inclusion layered material on the refractory material surface which contacts molten glass, the use site | part of a refractory material for glass manufacture, use temperature, etc. Thus, a refractory material for glass production having an optimum configuration can be used.

  (6) If the refractory material for glass production of the present invention has a thickness of less than 1 mm, the refractory noble metal-containing layered material is economically superior and can exhibit high heat resistance. Yes, it facilitates the production of homogeneous glass articles.

  (7) Moreover, if the refractory material for glass manufacture of this invention is a wall material mounted in a down draw molding apparatus, in addition to the above-mentioned effect, it will shape | mold efficiently glass articles, such as plate glass, which has a high molding dimension. Therefore, it is possible to supply glass articles to consumers.

  (8) Furthermore, the refractory material for glass production of the present invention has a bowl-shaped molten glass supply groove having an open top at the top, and the top of both side walls of the glass supply groove is used as an overflow weir, and the outer surface of both side walls. In addition to the above-mentioned various effects, if the part is a refractory material constituting a molded body in which the outer surfaces of both side walls face each other downward and are closed at the lower end so that the cross section is substantially wedge-shaped, Without passing through a processing step such as a polishing step, it is possible to economically and efficiently form a thin glass plate that enables high-precision control of the thickness dimension in the direction perpendicular to the opposing light-transmitting surface. In particular, it is suitable for forming a cover glass for a package that houses an image sensor such as a CCD or CMOS.

(9) The method for producing a refractory material for glass production according to the present invention comprises a processing step of pulverizing and mixing a Si-containing material and / or a Zr-containing material having an α-ray emission amount of 1.0 c / cm ² · hr or less, and If the pulverized product has a firing step of firing at a firing temperature of 1200 ° C. or higher, the α-ray emission amount of the refractory that has high density and can realize a stable strength is suppressed. It is possible to manufacture in a state, and it is possible to efficiently manufacture a refractory material for glass production that can be used in a portion in direct contact with molten glass that needs to be taken care of to avoid emission of α rays. .

  (10) In the glass melting furnace of the present invention, since the refractory material for glass production of the present invention is disposed as a furnace wall material in contact with the inorganic multicomponent molten glass, a glass article having a low α-ray radiation amount. Can be manufactured with high efficiency over a long period of time.

  (11) The method for producing a glass article of the present invention uses the glass melting furnace of the present invention to homogenize the molten glass, hot mold the homogenized molten glass, and perform a slow cooling operation after hot forming. As a result, glass articles with low α-ray radiation can be molded with high molding dimensions and stable surface quality, and optically high stability can be obtained by slow cooling operation. Therefore, it is easy to obtain a glass material that is homogeneous and has little variation in optical quality within the production lot when it is necessary to transmit light, for example, for use in a solid-state imaging device.

  (12) The method for producing a glass article of the present invention is capable of producing a stable and high-quality plate glass in a large amount at high speed if the molten glass is subjected to overflow molding using the refractory material for glass production of the present invention as a molded body. Therefore, it is possible to establish an economical manufacturing process with extremely high manufacturing efficiency.

  Hereinafter, a method for producing a refractory material for glass production and a refractory material for glass production according to the present invention, and a method for producing a glass article using the refractory material for glass production according to the present invention will be described based on examples.

  First, a more specific shape of the refractory material for glass production of the present invention used as a member of an overflow downdraw molding apparatus will be described with reference to FIG. FIG. 1 shows a perspective view of a refractory molded body mounted on an overflow downdraw molding apparatus for molding a highly accurate plate glass. In FIG. 1, 10 is a molded body, 11 is a molten glass supply groove, 12 is an overflow weir, 13 is an outer surface of a wedge-shaped side wall, 14 is a lower end of the molded body, and 15 is a top ridge line on both side walls.

With respect to the refractory material for glass production, the molded body 10 made of a refractory has an appearance as can be seen from FIG. The formed body 10 has a substantially wedge-shaped cross section perpendicular to the longitudinal direction, and a molten glass supply groove 11 is formed on the upper portion of the wedge shape for allowing molten glass to flow after melting in a glass melting furnace. It is made of a refractory material having a flange part, and the size is 300 mm in width, 700 mm in length, and 800 mm in height, and its composition is expressed in terms of mass percentage in terms of oxide, SiO ₂ 30.7%, ZrO ₂ 64.5%, ZnO 4.8%. This overflow downdraw molding apparatus in which a refractory material for glass production is used is for producing a thin glass sheet for a cover glass of a package that houses an image sensor such as a CCD or CMOS. This thin glass sheet is obtained by down-draw molding a thin glass sheet that requires a highly accurate dimension and homogeneity with a thickness of 0.5 mm from molten glass.

  In FIG. 1, the molten glass melted homogeneously in the glass melting furnace flows into the molten glass supply groove 11 of the refractory molded article 10 from the left front side to the right back side in FIG. After that, it overflows the overflow weir 12 and overflows from the ridges 15 on both side walls, flows along the outer surface of the refractory molded body 10, flows down the outer surfaces 13 of the wedge-shaped side walls, and joins at the lower end 14 of the molded body. It becomes a sheet glass body and is then cooled and cut to form a sheet glass. As shown here, the refractory molded body 10 continues to be in direct contact with the molten glass in a high temperature state, and particularly the wall material used for the wall surface such as the floor surface or the side wall surface of the molten glass supply groove 11 is: Since it will be used in contact with the molten glass in a high temperature state, when this molded body is used for forming a sheet glass for a long time, α-ray emitting elements such as U and Th contained in the wall surface material are Since it will be mixed in the molten glass, it is necessary that the α ray emission amount of the refractory for glass production is a sufficiently low value.

  Next, a method for manufacturing the refractory material 10 for manufacturing glass mounted on the overflow downdraw molding apparatus 20 will be specifically described.

First, select raw materials with a small amount of α-ray radiation, and confirm the level of α-ray emission when constructing a refractory molded body by combining the high-purity raw materials. Grind and mix until Here, the raw material is pulverized and mixed using a ball mill that can be used most simply. The raw material to be pulverized and mixed was selected as the SiO ₂ raw material having a SiO ₂ content of 99.8% or more in terms of mass percentage in terms of oxide, and the maximum content of impurities was Al ₂ O ₃ of 500 ppm or less. It is a natural silica mineral raw material (product code S-325) manufactured by Hiroura Mining Co., Ltd. Further, when the α-ray radiation amount of this SiO ₂ raw material was measured in advance with a 2π-type gas flow proportional counter under PR-10 gas inflow, the value was 0.04 c / cm ² · hr. Further, as a ZrO ₂ raw material, a high-purity zirconium oxide (product code H4) derived from natural ore and manufactured by Nippon Electric Works, Ltd. was selected, and the ZrO ₂ content of this high-purity zirconium oxide is 99 in terms of mass percentage in terms of oxide. 0.9% as impurities, and Ti was less than 0.01% and SiO ₂ was less than 0.01%. And the measurement result of the α-ray radiation amount by the same measurement method as described above for the ZrO ₂ raw material is a level of 0.3 c / cm ² · hr, even when the value is large, when a plurality of lots are investigated. All other lots had a measurement result of 0.3 c / cm ² · hr or less. Furthermore, this time, as a sintering aid for sintering this SiO ₂ and ZrO ₂ , a ZnO raw material having a ZnO content of 99.0% or more in terms of mass percentage in terms of oxide was used. This ZnO raw material is a high-purity ZnO raw material manufactured by Honjo Chemical Co., Ltd., and the maximum content of impurities is Pb having a quality of 0.3% or less in terms of oxide-based mass percentage.

In the operation of pulverization and mixing by a ball mill, SiO ₂ balls are used and wet pulverization and mixing are performed using ion-exchanged water in addition to raw materials. Thus finally the average particle size D ₅₀ by performing the process for a predetermined time to obtain a ground mixture of 8 to 10 [mu] m. Here, the average particle diameter is measured using a laser diffraction particle size distribution measuring apparatus (SALD-2000J, manufactured by Shimadzu Corporation). Thus, the pulverized mixture obtained in the processing step of pulverizing and mixing is baked for 10 hours under the condition of 1430 ° C. ± 50 ° C. while being filled in a refractory container. Thus, zircon (ZrO ₂ · SiO ₂ ) is synthesized from the above-mentioned SiO ₂ raw material and ZrO ₂ raw material. Next, as a powder crushing step for the synthetic product, the synthesized bulk zircon is crushed using a ball mill and classified so as to have a particle size suitable for firing the refractory molded body.

  Ion exchange water is added to the pulverized zircon obtained in the above-described crushing process of the synthetic product, and cast in a gypsum mold prepared in advance as a casting process (also referred to as slip casting), followed by drying after casting. Incidentally, although mud casting is employed here, a molding method such as HIP or CIP may be employed as necessary. The obtained mud cast body is taken out from the mold after a predetermined time, dried and then placed in a muffle-type firing furnace as a firing step, and fired at a firing temperature condition of 1400 ° C to 1500 ° C. Thus, the glass manufacturing refractory 10 to be mounted on the overflow downdraw molding apparatus 20 constituted by the dense synthetic zircon refractory is obtained.

The refractory material for glass production thus obtained has an α-ray emission amount of 1.0 c / cm ² · hr or less, and U and Th contents each having a level of 1 ppm or less. The total content of U and Th up to 10 mm from the surface in contact with the glass has a quality of 5 ppm / mm ² or less. The measurement method etc. are shown concretely. When the α-ray emission amount is measured by using a gas flow proportional counter under inflow of PR gas and measuring conditions under an electrode aperture area of 4000 cm ² for two days, the value is 0.10c. / Cm ² · hr, and the amount of α-ray emission is 1.0 c / cm ² · hr or less, which indicates that the configuration satisfies the requirements of the present invention. The total content of U and Th at a depth of 10 mm from the surface of the molten glass supply groove 11 in contact with the molten glass is at a level of 1 ppm / mm ² or less, and the content of U and Th is IPC. When measured by emission analysis, the values were 0.1 ppm or less for both U and Th, and there was no problem.

Moreover, the refractory material for glass manufacture of this invention evaluated the creep property in the following procedures. First, the refractory cut out to have a width of 40 mm, a length of 120 mm, and a height of 80 mm is placed on the heat-resistant fulcrum material so that the distance between the fulcrums is 80 mm, and is located at the center of the distance between the fulcrums. A refractory weight was placed on the upper surface of the refractory so that a load of 135 kg was applied and held in an electric furnace at 1250 ° C. for one day (24 hours), and then an evaluation was made based on whether deformation exceeding 500 μm was observed. However, no deformation exceeding 500 μm was observed, and no abnormality was found even when the crack generation state was examined, and it was found that the film had heat resistance of 950 ° C. or higher. Furthermore, the refractory material for glass production according to the present invention is a SiO ₂ 55-55 sample expressed by mass percentage in terms of oxide in order to evaluate the erosion property. _{69%, Al 2 O 3 3~16} %, B 2 O 3 7~20%, 0~5% MgO, CaO 0~10%, BaO 0~12%, SrO 0~10%, CaO + BaO + SrO + ZnO 0.3~ The refractory material is immersed in a molten glass having a composition of 13% corresponding to 10 ^3.9 dPa · s, that is, in a temperature range of 1100 ° C. to 1300 ° C. for 5 days (120 hours). When the surface erodibility was examined by microscopic observation and the naked eye, the surface was found to have high erosion resistance and high temperature durability with no defects such as immersion or cracks on the surface. Found it was.

  From the above evaluation results, the overflow downdraw molding apparatus using the refractory material for glass production according to the present invention has the advantage that it can form a highly accurate plate glass as described above. Since the refractory surface and the molten glass are in contact with each other, it is possible to prevent the radioactive elements from being eluted and mixed in the molten glass when the refractory surface comes into contact with the molten glass. It has a low α-ray emission.

  Subsequently, the manufacturing method of the glass article which uses the refractory material for glass manufacture of this invention is demonstrated concretely.

  FIG. 2 illustrates a partial perspective view of a glass forming apparatus to which the refractory material for glass production of the present invention is applied in FIG. 2, and FIG. 3 (A) and FIG. A procedure for manufacturing a glass article using this glass forming apparatus will be described. In FIG. 2, 10 is a molded body, 11 is a molten glass supply groove, 12 is an overflow weir, 13 is an outer surface of a wedge-shaped side wall, 14 is a lower end of the molded body, and 15 is a top edge of both side walls. , 20 is an overflow downdraw molding apparatus, 21 is a side wall guide member, 22 is a shoulder of the molded body, and 23 is a molten glass supply pipe insertion hole. 3A and 3B, in addition to the symbols in FIG. 2, 30 is a heat-resistant supply tube, 40 is a support member, G is a molten glass, F is a forming direction of sheet glass, and P is a sheet glass. Represents.

When forming the glass sheet using this overflow downdraw molding device 20, the cover glass for the image sensor (for example, a glass product code made by Nippon Electric Glass is used in a glass melting furnace (not shown). ABC and the like, _SiO 2 _55-69% by mass percentage of these glasses oxide _{equivalent, Al 2 O 3 3~16%,} B 2 O 3 7~20%, 0~5% MgO, CaO 0 Α-ray emission amount selected in advance so as to obtain an optimum aluminoborosilicate glass composition for a composition of 10% to 10%, BaO 0 to 12%, SrO 0 to 10%, CaO + BaO + SrO + ZnO 0.3 to 13%) The selected high-purity raw material with a small amount is heated after homogenous mixing at a predetermined distribution to obtain a molten glass state, and then the molten glass is homogenized with a stirrer etc. After performing work, it will be flowing with a heat supply pipe 30 disposed molten glass supply tube insertion hole 23 into the molten glass supply groove 11 in the molten glass G the overflow down draw forming device 20.

  Then, referring to the explanatory view showing the state in operation when the plate glass of FIG. 3 is formed, the molten glass G that has flowed into the molten glass supply groove 11 is dammed up by the overflow weir 12 and is once molten glass supply groove. 11, but then flows out beyond the top ridge line 15 on both side walls, flows downward along the outer surface 13 of the both side walls of the wedge shape, and flows at the lower end 14 of the formed body, that is, the flow of molten glass. Become. At this time, since the width of the stream is limited by the heat resistant metallic both side wall guide members 21 on the molded body shoulder 22 of the overflow downdraw molding apparatus 20, the width of the plate glass P is not excessively widened. It will be drawn out in the direction F and molded.

The thus obtained plate glass having a thickness of 0.5 mm is gradually cooled to room temperature and then cut to a predetermined size. Various methods may be adopted as the cutting method, but the most efficient method is, for example, a method using a laser. When the α-ray emission amount of the plate glass article obtained by such a manufacturing procedure is measured by a gas flow proportional counter under PR-10 gas inflow, the value becomes a high level of 0.002 c / cm ² · hr or less, In this manufacturing method, no precious metal that causes foreign matter such as platinum is used, so that there is no problem with Pt (platinum). Therefore, the cover glass mounted on the obtained CCD or CMOS package has a high level of quality not only in terms of homogeneity but also α-rays. If it is a shaping | molding apparatus which uses the refractory material for production, it will become possible to produce stably stably efficiently.

  Furthermore, the example which uses the refractory material for glass manufacture of this invention as a side wall material or hearth material of a glass melting furnace is demonstrated below.

  The glass melting furnace for melting the image sensor cover glass such as the BDA described above has conventionally used a melting furnace made of synthetic quartz or platinum, but uses the refractory material for glass production of the present invention as an alternative. It was examined whether it could be done. The wall material for the side wall of the glass melting furnace has a simple shape as compared with the molded body of the overflow downdraw molding apparatus. The external dimensions are, for example, a block material having a substantially rectangular parallelepiped shape of 200 mm × 400 mm × 600 mm, and the refractory material for glass production of the present invention is applied as the block material.

When the block material manufactured in the same procedure as described above is used for the bottom surface and the side wall surface of the glass melting furnace, the glass quality that has conventionally suffered from Pt (platinum) due to aging is stabilized. It was confirmed that a plate glass having a quality of 0.002 c / cm ² · hr or less with respect to the amount of α-ray emission can be obtained.

  Although the detailed configuration of this glass melting furnace is omitted, it has a melting chamber in which pre-adjusted glass raw materials are charged and melted, and a clarification chamber connected to the melting chamber. It is used, and stirring is performed under stirring conditions in which inhomogeneous parts such as striae disappear. And after that, it shape | molds with an overflow downdraw shaping | molding apparatus, and after forming plate glass, slow cooling operation is performed and the plate glass of the stable quality will be obtained.

About the refractory material for glass manufacture of this invention, it shows below about another example. The refractory material for glass production shown here relates to a configuration obtained by further remodeling the refractory material for glass production 10 mounted on the overflow downdraw molding apparatus 20 shown in the first embodiment. That is, even in the refractory material 10 for glass production described in Example 1 of the present invention, a molten glass having a level of α-ray emission of 1.0 c / cm ² · hr or less is obtained as described above, It was confirmed that a plate glass having a sufficiently low radiation emission ability was obtained. In addition, we conducted research on extending the useful life of the molded product so that the quality of the produced glass plate could be improved and the production of a stable plate glass over a long period of time could be realized. It has been found that the useful life can be extended by forming a sheet-like coating material.

This platinum sheet-like coating is a 0.8-mm-thick Pt film, measured in advance with respect to the amount of α-ray emission, and after confirming that the amount of α-ray emission is sufficiently low, Construction is performed so as to cover the surface of the body 10, and the surface in contact with the molten glass is covered with this Pt film. Then, as described above, the image sensor cover glass BDA was formed as a 0.5 mm plate glass by using it as a constituent member of the overflow downdraw molding apparatus 20. The α-ray emission amount of the obtained plate glass was 0.002 c / cm ² · hr or less, and it was confirmed that the α-ray emission amount was sufficiently low. In addition, as a result of suppressing deterioration of the surface of the refractory material exposed to the high-temperature molten glass for a long period of time, it has been found that the service life of the molded body can be extended as compared with the conventional one.

It is a perspective view of the refractory molded object mounted in the overflow downdraw molding apparatus of this invention. It is a fragmentary perspective view of an overflow downdraw molding apparatus. It is explanatory drawing regarding the time of shaping | molding of plate glass with an overflow downdraw shaping | molding apparatus, (A) is a top view, (B) represents sectional drawing about XX cross section of (A) figure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Molded object 11 Molten glass supply groove 12 Overflow weir 13 Wedge-shaped outer surface of both side walls 14 Molded body lower end 15 Both side wall top ridge line 20 Overflow down draw molding device 21 Both side wall guide member 22 Molded body shoulder 23 Molten glass supply pipe Insertion hole 30 Heat-resistant supply tube 40 Support member G Molten glass F Forming direction of plate glass P Plate glass

Claims (12)

It is a refractory material obtained by sintering two or more inorganic oxide particles,
A refractory material for glass production, wherein the amount of α-ray emission is 1.0 c / cm ² · hr or less.   The refractory material for glass production according to claim 1 or 2, wherein the U and Th contents of the inorganic oxide particles are each 1 ppm or less. The inorganic oxide contains one or more of SiO ₂ and ZrO ₂ , each of which is contained within a range of 20% to 80% in terms of mass percentage in terms of oxide. Refractory material for glass production as described in 1 or 2.   The refractory material for glass production according to any one of claims 1 to 3, wherein the sintering aid is contained in the range of 0.01% to 10% in terms of mass percentage in terms of oxide. .   The refractory material for glass production according to any one of claims 1 to 4, wherein a refractory noble metal-containing layered material is disposed on the surface of the refractory material in contact with the molten glass.   The refractory material for glass production according to claim 5, wherein the refractory noble metal-containing layered material has a thickness of less than 1 mm.   The refractory material for glass production according to any one of claims 1 to 6, wherein the refractory material is a wall material mounted on a downdraw molding apparatus.   It has a bowl-shaped molten glass supply groove with an open top at the top, the top of both side walls of this glass supply groove is used as an overflow weir, and the outer surface of both side walls has a substantially wedge-shaped cross section. The refractory material for glass production described in any one of claims 1 to 7, wherein the refractory material is a refractory material that forms a molded body that is made to approach each other downward and terminated at the lower end. a processing step of pulverizing and mixing a Si-containing raw material and / or a Zr-containing raw material having an α-ray emission amount of 1.0 c / cm ² · hr or less, and a baking step of baking the obtained pulverized product at a baking temperature of 1200 ° C. or higher The manufacturing method of the refractory material for glass manufacture characterized by having.   A glass melting furnace, wherein the refractory material for glass production according to any one of claims 1 to 5 is disposed as a furnace wall material in contact with the inorganic multi-component molten glass.   A method for producing a glass article, comprising: homogenizing a molten glass using the glass melting furnace according to claim 10; hot forming the homogenized molten glass; and performing a slow cooling operation after the hot forming.   A method for producing a glass article, wherein the molten glass is overflow molded using the refractory material for glass production according to claim 1 as a molded body.

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