JP2006077318A - Method for modifying surface of apparatus for producing glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment method for inhibiting platinum from causing an change like volatilization loss, which can occur on the outer surface of an apparatus for producing glass while being operated. <P>SOLUTION: The treatment method for modifying the outer surface of the apparatus for producing glass, which is made from a platinum material containing platinum or a platinum alloy comprises: forming a coating layer containing a refractory material on the outer surface of the apparatus for producing glass; and drying and baking the coating layer. Here, the coating layer is preferably formed with the method of applying a sol containing the refractory material to the outer surface of the apparatus, or the method of sticking a kneaded substance (green sheet) containing the refractory material to the outer surface of the apparatus. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a construction method for modifying the outer surface of a material constituting a glass manufacturing apparatus, and in particular, a construction method for forming a coating layer on the outer surface of the apparatus and blocking contact between the equipment constituent material and the outside air. It is about.

Glass manufacturing apparatuses often use platinum or a platinum alloy as a constituent material. Platinum has a high melting point and does not deteriorate because it does not form an oxide layer in the atmosphere. In addition to its low risk of deformation and damage during operation, it has excellent chemical stability and may contaminate molten glass. Is due to low. And as this platinum material, platinum alloys, such as platinum-rhodium alloy other than platinum, are widely used (as for the platinum material applicable to the glass industry, details are given in the column of conventional technology in Patent Document 1). Are listed.).
Japanese Patent Laid-Open No. 10-280070

  The apparatus temperature in a glass manufacturing process is 1200-1300 degreeC near the lowest stirring tank exit, and is 1600 degreeC in the clarification tank with the highest temperature. Thus, although the operating temperature of each apparatus changes with the processing contents, all are in the high temperature environment of 1000 degreeC or more. The platinum material can maintain sufficient durability for a long period of time without contaminating the molten glass inside the apparatus even in such a high temperature environment due to the above characteristics.

Incidentally, in the glass manufacturing apparatus comprising such platinum material, an outer surface in contact with the outside air, the platinum oxide is gaseous oxide (PtO ₂₎ platinum volatile loss due to is generated occurs. The amount of volatilization due to the volatilization of platinum reaches several percent of the weight of the platinum device in normal use, and directly injures the strength and stability of the platinum material at a site where the amount of volatilization is locally large. Moreover, since the volatilized platinum adheres to a refractory material and a heat insulating material installed around the glass manufacturing apparatus, a large number of members become targets for platinum recovery and purification. In addition, the loss due to volatilization of expensive platinum materials in difficult to recover spaces is also significant.

  Then, an object of this invention is to show the construction method for the modification | reformation process which can suppress the change which can arise on the outer surface of a glass manufacturing apparatus, such as volatilization loss of platinum.

  As a means for suppressing the surface change of the platinum material, it is conceivable to modify the material itself by adjusting the components, but this means may impair other properties such as high-temperature strength. It takes time and effort to investigate and study the material properties after modification. Therefore, the present inventor considered that a method of coating the surface of the platinum material with an appropriate coating layer is effective as a measure for solving the problem of surface change without impairing the original characteristics of the platinum material.

  The present invention is a construction method for modifying an outer surface of a glass manufacturing apparatus made of platinum or a platinum material made of a platinum alloy, wherein a coating layer containing a refractory material is formed on the outer surface of the glass manufacturing apparatus. The surface modification construction method for a glass manufacturing apparatus for drying and firing the coating layer.

  Here, the refractory material refers to a high melting point material that can maintain a solid state without being burnt, volatilized, or melted even at a high temperature of 1000 ° C. or higher. For example, alumina, silica, zirconia, mullite, etc. These metal oxides can be mentioned. By forming such a coating layer containing a refractory material, it is possible to block the outer surface of the apparatus and the outside air even under a high temperature environment and suppress the volatilization of platinum.

  This coating layer may be made of only a refractory material, and may contain subcomponents such as a binder and additives. And as a preferable structure of a coating layer, a refractory material powder and a glass component are mixed. In this coating layer, the gap between the refractory material powders is filled with glass, and the refractory particles are dispersed in the glass component. And since the dimensional change of a glass manufacturing apparatus can be tracked by the softness | flexibility of the glass component of a parent phase, the apparatus outer surface can be coat | covered without fracture | rupture also at the time of a driving | operation of a glass manufacturing apparatus, and a stop.

  And as a formation method of a coating layer, the method of making the component sol (suspension) and apply | coating this to the apparatus outer surface is mentioned first. In order to completely block the outer surface of the apparatus from the outside air, it is necessary to form a dense coating layer. Therefore, it is preferable to repeatedly apply spraying as a sol coating method. .

  The applied sol can be manufactured by appropriately dispersing the powder of the refractory material constituting the coating layer in water or an organic solvent. When a glass component is included as a constituent component of the coating layer, it may be dispersed in a solvent together with the refractory material powder. The refractory powder may be pulverized in advance in order to make the coating layer dense.

  The sol is preferably applied by spraying as described above, and air-assisted spray application is preferred. In this spraying, the produced sol is sent to a nozzle via a pump or the like and sprayed. However, it is preferable to feed the sol while stirring it uniformly.

  By the way, the method of spraying sol as a method for forming the coating layer is useful for forming a uniform coating layer regardless of the shape of the target glass production apparatus, but the film thickness of the coating layer to be formed is not limited. Has a limit, and it takes time and effort to form a thick film of the order of mm even if it is repeatedly applied. In addition, metal oxides suitable as refractories described above have a high melting point, and it is difficult to obtain a dense material by firing, and many of them are porous. Therefore, a relatively thin coating layer formed by spray coating is used. There is a risk that defects such as pinholes may remain. Therefore, as a method for forming a thick coating layer in which defects do not easily remain, it is preferable to employ a method in which a kneaded material having plasticity is formed using a refractory as a raw material, and this is adhered to the outer surface of the apparatus.

  As the kneaded material to be adhered, a kneaded product obtained by adding cellulose, a polyester resin, a polyvinyl acetal resin, or the like as a binder to a powder of a refractory material can be applied. The kneaded product to be stuck may be in the form of clay, or may be stuck as a green sheet formed into a sheet shape by a doctor blade device or an extrusion process.

  Moreover, before sticking the refractory kneaded material to a glass manufacturing apparatus, you may apply | coat sol containing the above-mentioned refractory material, and may stick a kneaded material after that. Since some glass manufacturing apparatuses have complicated shapes, a coating layer can be reliably formed by applying a sol with good throwing power and then sticking the kneaded material.

  For the coating layer formed by applying the above sol or sticking a green sheet, in order to remove the solvent contained and improve the strength, it is further dried to improve the adhesion to the outer surface of the apparatus as a substrate. A baking process is performed. Here, about drying of a coating layer, it is preferable to heat and dry from the inner surface of a glass manufacturing apparatus. Even if the coating layer is directly heated and dried, the coating layer can be temporarily dried, but the coating layer may be cracked or peeled off in the process, which may affect the film quality. Moreover, when forming a coating layer by application | coating of sol, a drying process can be performed simultaneously with application | coating of sol. In addition, although the temperature at the time of drying is based also on the component, it is preferable to carry out at 40 to 95 degreeC. FIG. 1 schematically shows an example of a method of forming a coating layer on a glass manufacturing apparatus (tank) and drying it.

  About the baking conditions of a coating layer, although depending on the component, it is preferable to carry out at 1200 to 1600 degreeC. Baking may be performed in the open air. Moreover, if the apparatus to coat | cover is small, it can carry out in heating furnaces, such as an electric furnace.

  In this firing step, it is preferable to degrease by taking a sufficient heating time in a temperature range of about 200 ° C. to 500 ° C. before heating in the above temperature range. Thus, it is preferable to perform this degreasing work when forming the coating layer. This is because the green sheet contains an organic component such as a binder, so if the degreasing is insufficient, the decomposition products generated from the organic component can remain as a gas in the coating layer. There is sex. In such a case, there is a concern that the residual decomposition product reacts with the platinum material and causes the strength deterioration of the platinum material.

  The coating layer according to the present invention may be formed after the coating layer is formed, dried and fired for individual devices such as a clarification tank, a stirring tank, and a communication channel. Alternatively, the coating layer formation and the drying process may be performed for each device, and after the devices are connected, a series of devices may be heated to perform the baking treatment. In addition, although it is common to connect each apparatus by welding, when baking is performed after connecting an apparatus as mentioned above, welding will become difficult if a coating layer is previously formed in a welding part. Therefore, it is preferable to apply the kneaded material of the refractory powder to the welded portion after welding (after connecting each device) without forming a coating layer on the welded portion.

  Moreover, it is common for a glass manufacturing apparatus to install a protective refractory around it. When installing this protective refractory, a kneaded material containing the same refractory material as described above was attached to the outer surface of the glass manufacturing apparatus after the coating layer was formed, or to the glass manufacturing apparatus side surface of the protective refractory. Afterwards, it is preferable to install protective refractories. Thereby, a refractory material is filled between the glass manufacturing apparatus and the protective refractory, and suppression of volatilization loss can be further ensured.

  ADVANTAGE OF THE INVENTION According to this invention, the volatilization loss of platinum which has not been supported so far about a glass manufacturing apparatus can be suppressed effectively.

  Hereinafter, preferred embodiments of the present invention will be described together with comparative examples.

First Embodiment Here, the coating layer comprising a refractory material and a glass component, and it is formed on the entire surface of the plate material made of platinum alloy, spraying a sol containing a refractory material and a glass component coating, drying and baking processes Was done. As the refractory, two kinds of metal oxides of alumina and silica were used. As the glass component, Nippon Electric Glass Co., Ltd. alkali-free aluminoborosilicate glass (material name OA-10 composition _{(wt%): SiO 2 60%,} B 2 O 3 10%, Al 2 O 3 15%, CaO 5%, SrO 5%, BaO 2%) were used. As the solvent, a 1.5 wt% methylcellulose aqueous solution was used. The final composition of the coating layer to be manufactured was set as follows.

Alumina: 36.5% by weight
Silica: 23.5% by weight
Glass component: 40.0% by weight
Solvent: 200% by weight (amount based on the coating layer weight)

  The sol mixed in the above distribution was spray-applied to both surfaces and end surfaces of platinum-10 wt% rhodium plates (size 75 mm □ × 1.0 mm). FIG. 2 shows an apparatus configuration when spraying sol. The prepared sol was fed to a spray nozzle through a liquid feed pump while being stirred with a stirrer and sprayed with air assist. In this embodiment, the sol was applied and dried at the same time. The drying was performed on both sides by spraying the sol while heating with a hot air gun from the back side of the plate. The application conditions were a spray air flow rate of 10 L / min and a pattern air flow rate of 15 L / min. The coating thickness was calculated by measuring the change in the weight of the plate material, and was 150 μm.

  And after drying the coating layer, the board | plate material was baked at 1300 degreeC and formation of the coating layer was completed.

Second Embodiment : Here, a green sheet was manufactured, and this was adhered to the entire surface of a plate material made of a platinum alloy, thereby forming the same coating layer as in the first embodiment. The green sheet was formed into a sheet by extruding after mixing powders of alumina, silica, and glass components with the same composition as in the first embodiment, kneading an acrylic polymer as a binder and toluene as a solvent. The kneaded composition was 66.2% powder, 17.9% acrylic polymer, and 15.9% toluene. The size of the green sheet after molding was 100 mm × 500 mm × 1.0 mm, and it was cut at 76 mm □, which is 1 mm larger than the plate material size.

  And the manufactured green sheet was affixed on the platinum alloy board | plate material. At this time, the green sheet was adhered while the plate surface was wetted with a solution in which the acrylic polymer and toluene used for green sheet preparation were mixed at a weight ratio of 53:47. And after drying the coating layer, the board | plate material was baked at 1300 degreeC and formation of the coating layer was completed.

  As described above, the presence or absence of platinum volatilization loss was examined for the platinum alloy plate material on which the coating layer was formed. This examination was performed by heating the crucible at 1300 ° C. and 1500 ° C. for 100 hours in the outside air, and measuring the change in weight after heating. The results are shown in Table 1. Table 1 also shows the test results of the Pt-10 wt% Rh alloy plate material on which no coating material is formed.

  From Table 1, it was confirmed that the platinum loss of the platinum alloy coated with the coating material formed in each embodiment is close to zero and has an excellent protective action. This is the same even at a high temperature of 1500 ° C. or higher. On the other hand, in the platinum alloy not coated with the coating material, it was confirmed that a platinum loss of 0.1 g or more occurred, and the amount thereof increased as the temperature increased.

Application Example to Glass Manufacturing Apparatus Next, an embodiment of the glass manufacturing apparatus to which the present invention is applied and a display glass manufacturing method using this apparatus will be described.

  FIG. 3 shows an apparatus configuration for producing high-quality glass such as optical glass and display glass. In this figure, the glass manufacturing apparatus 1 is provided in the substantially rectangular dissolution tank 2 used as the supply source of molten glass, the clarification tank 3 provided in the downstream of the dissolution tank 2, and the downstream of the clarification tank 3. It has the stirring tank 4 and the shaping | molding apparatus 5 provided in the downstream of the stirring tank 4. FIG. And the dissolution tank 2, the clarification tank 3, the stirring tank 4, and the shaping | molding apparatus 5 are connected by the communication flow paths 6, 7, and 8, respectively.

  The dissolution tank 2 has a bottom wall, side walls, and a ceiling wall, and each of these walls is formed of a refractory material. The melting layer 2 is provided with a burner, an electrode, etc., and can melt the glass raw material. An outlet is formed in the downstream side wall of the dissolution tank 2, and the dissolution tank 2 and the clarification tank 3 communicate with each other via a narrow communication channel 6 having the outlet at the upstream end. .

  The clarification tank 3 has a bottom wall, a side wall, and a ceiling wall. The inner wall surface of the bottom wall and the side wall (at least the inner wall surface part in contact with the molten glass) is formed of platinum or a platinum alloy, and a protective refractory is installed on the outside thereof. In the clarification tank 3, the downstream end of the outflow passage 6 is opened in the upstream side wall. This clarification tank 3 is a part where clarification of glass is mainly performed, and fine bubbles contained in the glass are levitated and expanded by the clarification gas released from the clarifier, and are removed from the glass. An outlet is formed on the downstream side wall of the clarification tank 3, and the stirring tank 4 communicates with the downstream side of the clarification tank 3 via a narrow communication channel 7 having the outlet at the upstream end.

  The stirring tank 4 has a bottom wall, a side wall, and a ceiling wall. The inner wall surface of the bottom wall and the side wall (at least the inner wall surface part in contact with the molten glass) is formed of platinum or a platinum alloy, and a protective refractory is installed on the outside thereof. The stirring tank 4 is a part where the molten glass is stirred and homogenized mainly by a stirrer or the like.

  An outlet is formed in the side wall on the downstream side of the stirring tank 4, and the molding device 5 communicates with the downstream side of the stirring tank 4 via a narrow communication channel 8 having the outlet at the upstream end.

  As the molding device 5, for example, in the case of molding glass for display, a plate glass molding device such as a downdraw molding device, an updraw molding device, or a float molding device is used. In particular, in the case of a plate glass for liquid crystal, an overflow downdraw apparatus is suitable.

  The communication channel 6 that connects the dissolution tank 2 and the clarification tank 3 is formed of a refractory, while the other communication channel, that is, the communication flow that connects the clarification tank 3 and the stirring tank 4. The channel 7 and the communication channel 8 that connects the stirring tank 4 and the molding device 5 are formed of platinum or a platinum alloy, and a protective refractory is installed on the outside thereof.

  In the present embodiment, in the glass manufacturing apparatus described with reference to FIG. 3, the same surface as that of the second embodiment described above is formed on the outer surface of a glass manufacturing apparatus (here, clarification tank 2 to communication channel 8) made of platinum or a platinum alloy. A green sheet was adhered to form a coating layer. And the method of manufacturing the glass for displays using a glass manufacturing apparatus provided with this coating layer is as follows.

First, a glass raw material is prepared. For example, in order to obtain a glass having a composition of SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ —RO (RO is one or more of MgO, CaO, BaO, SrO and ZnO), specifically, SiO ₂ 50-70% in _{percentage, Al 2 O 3 10~25%,} B 2 O 3 5~20%, 0~10% MgO, CaO 3~15%, BaO 0~10%, SrO 0~10% , ZnO 0 to 10%, TiO ₂ 0 to 5%, P ₂ O ₅ 0 to 5% Alkaline free glass is prepared to prepare the glass raw material. In addition to the above, various components such as a fining agent can be added.

Subsequently, the prepared glass raw material is charged into the melting tank 2 and melted and vitrified. In the melting tank 2, the glass is heated from above by the combustion flame of the burner. In the case of the SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ —RO glass, the glass is melted at about 1500 to 1650 ° C.

  The molten glass vitrified in the melting tank 2 is guided to the clarification tank 3 through the communication channel 6. The molten glass contains initial bubbles generated during the vitrification reaction. In the clarification tank 3, the initial bubbles are lifted and removed by the clarification gas released from the clarifier component.

  The molten glass clarified in the clarification tank 3 is guided to the stirring tank through the communication channel 7. In the stirring vessel 4, the glass is stirred and homogenized by a rotating stirrer.

  The molten glass homogenized in the stirring tank 4 is guided to the molding device 5 through the communication channel 8 and molded into a plate shape. In this way, a display glass can be obtained.

  In the glass manufacturing apparatus according to the present embodiment, the volatilization loss of platinum from the manufacturing apparatus was suppressed even after the apparatus was operated for a long time when the above glass manufacturing method was performed. As a result, the strength and stability of the manufacturing apparatus have been maintained for a long time. Note that the apparatus according to the present embodiment is naturally applicable to the manufacture of glass other than display glass.

The figure explaining the drying process of a coating layer. The figure which shows the structure of the spray application apparatus of the sol used in embodiment. The figure which shows an example of the apparatus structure of a glass manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass manufacturing apparatus 2 Melting tank 3 Clarification tank 4 Stirring tank 5 Molding apparatus 6, 7, 8 Connection flow path

Claims (7)

A construction method for modifying the outer surface of a glass manufacturing apparatus made of a platinum material made of platinum or a platinum alloy,
A method for surface modification of a glass manufacturing apparatus, wherein a coating layer comprising a refractory material is formed on an outer surface of the glass manufacturing apparatus, and the coating layer is dried and fired. 2. The surface modification construction method for a glass manufacturing apparatus according to claim 1, wherein the coating layer is formed by applying a sol containing a refractory material to the outer surface of the apparatus. The method for surface modification of a glass manufacturing apparatus according to claim 1, wherein the coating layer is formed by sticking a kneaded material containing a refractory material to the outer surface of the apparatus. The method for surface modification of a glass manufacturing apparatus according to claim 3, wherein the sol containing the refractory material is applied to the outer surface of the apparatus to form a coating layer before the kneaded material including the refractory material is adhered to the outer surface of the apparatus. The method for surface modification of a glass manufacturing apparatus according to any one of claims 1 to 4, wherein the coating layer is dried from the inner surface of the glass manufacturing apparatus. The glass manufacturing apparatus by which a coating layer is formed in an outer surface by the method of any one of Claims 1-5. A method for installing a protective refractory on a glass manufacturing apparatus having a coating layer formed by the method according to claim 6,
A method of installing a protective refractory after attaching a kneaded material containing a refractory material to the outer surface of a glass manufacturing apparatus on which a coating layer is formed or the glass manufacturing apparatus side surface of a protective refractory.

Images