Cooling annealing process and cooling equipment for crucible melting

Abstract

The invention discloses a cooling annealing process and cooling equipment for crucible founding, and relates to the technical field of crucible preparation, and the cooling annealing process comprises the steps of crucible founding, quenching stage, slow cooling stage and natural cooling stage. Wherein in the step of melting the crucible, a crucible mold containing quartz sand is placed in a melting furnace for melting the crucible; in the rapid cooling stage, cooling air is introduced into the crucible mold, and circulating cooling water is adopted to rapidly cool the crucible mold; in the step of the slow cooling stage, the crucible mold is slowly cooled through circulating cooling water; in the step of the natural cooling stage, cooling air is introduced into the crucible mold so as to naturally cool the molten crucible. According to the cooling annealing process for crucible melting, provided by the invention, thermal stress generated in the crucible melting process can be effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of crucible preparation, and more specifically, to a cooling annealing process and cooling equipment for crucible melting. Background Art

[0002] During the Czochralski single crystal pulling process, the quartz crucible serves as a container for the polycrystalline silicon raw material. Within the crucible, the polycrystalline silicon material melts into a silicon melt in a high-temperature environment. Driven by the seed crystal, single crystal silicon rods of varying sizes are then pulled. Variations in crucible performance directly impact single crystal silicon yield. Thermal stress is generated during the crucible melting process, and this stress is released during the Czochralski single crystal pulling process. This can lead to cracks and silicon leakage in the crucible over short operating times, severely impacting single crystal production efficiency. Furthermore, silicon leakage poses a safety risk.

[0003] Therefore, how to reduce the thermal stress generated during the crucible melting process has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of the present application is to provide a cooling annealing process for crucible melting, so as to reduce the thermal stress generated during the crucible melting process.

[0005] Another object of the present application is to provide a cooling device for the above cooling annealing process.

[0006] To achieve the above objectives, this application provides the following technical solutions:

[0007] A cooling annealing process for crucible melting, comprising the steps of:

[0008] Melting the crucible: placing the crucible mold filled with quartz sand in a melting furnace to melt the crucible;

[0009] In the rapid cooling stage, cooling air is introduced into the crucible mold, and circulating cooling water is used to cool the crucible mold to rapidly cool the melted crucible;

[0010] In the slow cooling stage, the crucible mold is cooled by the circulating cooling water to slowly cool the melted crucible;

[0011] During the natural cooling stage, cooling air is introduced into the crucible mold to naturally cool the melted crucible.

[0012] Optionally, in the cooling annealing process, in the rapid cooling stage, the flow rate of the cooling air is 20L / min to 30L / min, the flow rate of the circulating cooling water is 300L / min to 600L / min, and the rotation speed of the crucible mold is 60rpm to 80rpm.

[0013] Optionally, in the cooling annealing process, in the slow cooling stage, the flow rate of the circulating cooling water is 150 L / min to 300 L / min, and the rotation speed of the crucible mold is 40 rpm to 60 rpm.

[0014] Optionally, in the cooling annealing process, in the natural cooling stage, the flow rate of the cooling air is 20 L / min to 30 L / min, and the rotation speed of the crucible mold is 60 rpm.

[0015] Optionally, in the above cooling annealing process, the melting crucible specifically includes the steps of:

[0016] Scraping and molding: loading the quartz sand of different levels into the crucible mold in sequence, scraping and molding, and placing the crucible mold in a melting furnace;

[0017] Melting the transparent layer, evacuating the melting furnace, and heating the quartz sand in the crucible mold by starting an arc with an electrode to form the transparent layer of the crucible;

[0018] The bubble layer is melted, the vacuuming of the melting furnace is stopped, and the quartz sand in the crucible mold is heated by starting an arc with an electrode to form a bubble layer of the crucible.

[0019] Optionally, in the above-mentioned cooling annealing process, in the step of melting the transparent layer, a vacuum pumping device is used to perform the vacuum pumping treatment on the melting furnace, and the vacuum degree of the melting furnace is controlled to be -0.085MPa to -0.095MPa by adjusting the opening of the vacuum valve of the vacuum pumping device.

[0020] Optionally, in the cooling annealing process, in the step of melting the transparent layer, the vacuuming is performed 0s to 30s after the electrode arc is started, and the duration of the vacuuming is 10min to 25min, and the vacuum pump of the vacuuming equipment has a pumping speed of no more than 1200m / s. 3 / h, and the power of the electrode is 1000kW to 2500kW.

[0021] Optionally, in the cooling annealing process, in the step of melting the bubble layer, the power of the electrode is 2000kW to 2500kW, and the melting time of the melting furnace is 10min to 20min.

[0022] Optionally, in the above cooling annealing process, the rapid cooling stage, the slow cooling stage and the natural cooling stage are all carried out in the melting furnace.

[0023] A cooling device for use in the cooling annealing process as described in any one of the above items, comprising:

[0024] a water-cooling assembly comprising a water-cooling jacket and a heat shield, wherein the water-cooling jacket is disposed on the outside of the crucible mold, the heat shield is located on the opening side of the crucible mold, and both the heat shield and the water-cooling jacket are provided with cooling channels for flowing the circulating cooling water;

[0025] An air-cooling assembly includes an air inlet main pipe and an air inlet branch pipe connected to the air inlet main pipe, wherein there are at least two air inlet branch pipes, and the air outlets of the two air inlet branch pipes respectively extend into the crucible mold and face the straight wall section and the connecting section of the melted crucible, so as to respectively transport the cooling air to the straight wall section and the connecting section of the crucible through the air outlets of the two air inlet branch pipes. The air inlet main pipe and the air inlet branch pipe are provided with an interlayer cooling channel for passing cooling water to prevent the air-cooling assembly from being damaged by high temperature.

[0026] The present application provides a cooling annealing process for crucible melting, comprising a crucible melting step, a rapid cooling stage, a slow cooling stage, and a natural cooling stage. In the crucible melting step, a crucible mold filled with quartz sand is placed in a melting furnace for crucible melting; in the rapid cooling stage, cooling air is introduced into the crucible mold and circulating cooling water is used to rapidly cool the crucible mold; in the slow cooling stage, the crucible mold is slowly cooled by circulating cooling water; and in the natural cooling stage, cooling air is introduced into the crucible mold to naturally cool the melted crucible. It can be seen from the above examples that the cooling annealing process for crucible melting provided by the present application, since the crucible after melting is still in the plastic stage, the crucible will not crack if it is rapidly cooled. In the slow cooling stage, the quartz crystal transformation temperature causes the volume shrinkage stress to increase. The cooling air can be turned off and the crucible can be slowly cooled using circulating cooling water to reduce the generation of shrinkage stress. In the natural cooling stage, the quartz crystal has completed the transformation. At this time, the circulating cooling water can be turned off and the crucible can be naturally cooled using cooling air, thereby effectively reducing the thermal stress generated during the crucible melting process, so that the thermal stress of the crucible in the production process is better released, and the use strength of the crucible itself is improved.

[0027] The technical features mentioned above, the technical features described below, and the technical features shown individually in the accompanying drawings may be combined arbitrarily, as long as the combined technical features do not conflict with each other. All possible feature combinations are technical contents explicitly described in this document. Any of the multiple sub-features included in the same statement can be applied independently and does not necessarily have to be applied in conjunction with the other sub-features. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0029] Figure 1 A schematic diagram of the cooling annealing process according to an embodiment of the present application;

[0030] Figure 2 A schematic diagram of a process for melting a crucible provided in an embodiment of the present application;

[0031] Figure 3 Schematic diagram of the cooling device provided in the embodiment of the present application Figure 1 ;

[0032] Figure 4 Schematic diagram of the cooling device provided in the embodiment of the present application Figure 2 ;

[0033] Figure 5 A schematic diagram of temperature changes during the cooling process provided in Example 1 of the present application;

[0034] Figure 6 A schematic diagram of temperature changes during the cooling process provided in Example 2 of the present application;

[0035] Figure 7 A schematic diagram of temperature changes during the cooling process provided in Example 3 of the present application;

[0036] Figure 8 A temperature distribution cloud diagram of a conventionally cooled crucible provided in an embodiment of the present application;

[0037] Figure 9 A cloud diagram showing the residual thermal stress distribution of a conventionally cooled crucible provided in an embodiment of the present application;

[0038] Figure 10 A temperature distribution cloud diagram of a cooled crucible provided in an embodiment of the present application;

[0039] Figure 11 This is a cloud diagram of the residual thermal stress distribution of the cooled crucible provided in an embodiment of the present application.

[0040] Among them, 1 is the crucible mold, 2 is the water cooling jacket, 3 is the heat shield, 4 is the air cooling component, 41 is the air inlet main pipe, 411 is the regulating valve, 42 is the air inlet branch pipe, 421 is the air outlet, and 5 is the electrode. DETAILED DESCRIPTION

[0041] The core of this application is to provide a cooling annealing process for crucible melting to reduce the thermal stress generated during the crucible melting process.

[0042] Another core of the present application is to provide a cooling device for the above cooling annealing process.

[0043] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0044] During the Czochralski single crystal pulling process, the quartz crucible serves as a container for the polycrystalline silicon raw material. Within the crucible, the polycrystalline silicon material melts into a silicon melt in a high-temperature environment. Driven by the seed crystal, single crystal silicon rods of varying sizes are then pulled. Variations in crucible performance directly impact single crystal silicon yield. Thermal stress is generated during the crucible melting process, and this stress is released during the Czochralski single crystal pulling process. This can lead to cracks and silicon leakage in the crucible over short operating times, severely impacting single crystal production efficiency. Furthermore, silicon leakage poses a safety risk.

[0045] In the traditional crucible preparation process, when the crucible is melted, the crucible mold is generally taken out of the melting furnace and cooled naturally by a simple method, that is, placed at room temperature for 2 minutes to 5 minutes, and then the crucible is demolded. The above cooling method cannot reduce the thermal stress in the crucible, which will cause cracks and silicon leakage in the crucible under a short operating time, which will seriously affect the single crystal production efficiency. At the same time, silicon leakage will pose a safety risk.

[0046] For this reason, Figure 1 As shown, the embodiment of the present application discloses a cooling annealing process for crucible melting, including step S100 of melting the crucible, step S101 of the rapid cooling stage, step S102 of the slow cooling stage, and step S103 of the natural cooling stage. Since the crucible after melting is still in the plastic stage, rapid cooling of the crucible will not cause cracking. In the slow cooling stage, the quartz crystal form changes temperature, causing the volume shrinkage stress to increase. The cooling air can be turned off and the crucible can be slowly cooled using circulating cooling water to reduce the generation of stress. In the natural cooling stage, the quartz crystal form has completed the transformation. At this time, the circulating cooling water can be turned off and the crucible can be naturally cooled using cooling air, thereby effectively reducing the thermal stress generated during the crucible melting process, allowing the thermal stress of the crucible to be better released during the production process, and improving the use strength of the crucible itself.

[0047] The following will be combined Figures 1 to 11The cooling annealing process for crucible melting disclosed in the embodiments of the present application is specifically explained and illustrated.

[0048] Step S100, melting a crucible;

[0049] The crucible mold 1 filled with quartz sand is placed in a melting furnace to melt the crucible. Specifically, Figure 2 As shown, step S100 of melting the crucible may include step S100a of scraping and forming, step S100b of melting the transparent layer, and step S100c of melting the bubble layer.

[0050] Step S100a, scraping and forming;

[0051] Different levels of quartz sand are sequentially loaded into the crucible mold 1 and scraped flat to form, and the crucible mold 1 is placed in a melting furnace. Among them, the crucible can be made by sequentially loading quartz sand of various specifications into the crucible mold 1 and scraping flat to form. Specifically, the crucible mold 1 can be tilted first, and different levels of quartz sand are sequentially loaded into the crucible mold 1, and the crucible mold 1 is rotated so that the quartz sand is evenly laid on the straight wall section of the crucible mold 1 and scraped flat to form the straight wall section of the crucible; then, the crucible mold 1 is placed upright, and quartz sand of various specifications is sequentially loaded into the crucible mold 1, and the crucible mold 1 is rotated so that the quartz sand is evenly laid on the bottom wall and connecting section of the crucible mold 1 and scraped flat to form the bottom wall and connecting section of the crucible. After all the quartz sand is loaded into the crucible mold 1 and scraped flat to form, the entire crucible mold 1 is placed in a melting furnace for melting. It should be noted that different levels of quartz sand refer to quartz sand with different particle sizes and silica contents, and the specific selection can be based on actual conditions. When loading and leveling, the quartz sand of the same level can be divided into several batches, that is, one or more times, and placed in the crucible mold 1. The quartz sand is leveled each time it is placed to ensure the uniformity of the quartz sand in each layer and improve the quality of the crucible molding.

[0052] Step S100b, melting the transparent layer;

[0053] The melting furnace is evacuated, and the quartz sand in the crucible mold 1 is heated by starting an arc through the electrode 5 to form a transparent layer of the crucible. Specifically, a vacuum device can be used to evacuate the melting furnace, and the vacuum degree of the melting furnace is controlled to be -0.085MPa to -0.095MPa by adjusting the opening of the vacuum valve of the vacuum device. In addition, the vacuum is carried out 0s to 30s after the electrode 5 starts the arc, that is, the vacuum intervention time needs to be controlled at 0s to 30s after the electrode 5 starts the arc, and the duration of the vacuum needs to be controlled at 10min to 25min. The pumping speed of the vacuum pump of the vacuum device is not more than 1200m 3 / h, that is, the maximum pumping speed of the vacuum pump is 1200m 3 / h, and the power of the electrode 5 can be 1000kW to 2500kW.

[0054] Step S100c, melting the bubble layer;

[0055] The melting furnace is stopped from being vacuumed, and an arc is struck by the electrode 5 to heat the quartz sand in the crucible mold 1 to form a bubble layer for the crucible. Specifically, the power of the electrode 5 can be 2000kW to 2500kW, and the melting time of the melting furnace can be controlled to be 10 minutes to 20 minutes to form the bubble layer of the crucible, thereby completing the crucible melting process.

[0056] After the crucible is melted, it enters the cooling and annealing stage, which may include:

[0057] Step S101, rapid cooling stage;

[0058] Cooling air is introduced into the crucible mold 1, and circulating cooling water is used to cool the crucible mold 1 to rapidly cool the melted crucible. Specifically, the cooling air flow rate can be controlled to 20L / min to 30L / min, the circulating cooling water flow rate to 300L / min to 600L / min, and the rotation speed of the crucible mold 1 to 60rpm to 80rpm to achieve rapid cooling of the melted crucible in the crucible mold 1. Since the melted crucible is in the plastic stage, rapid cooling of the melted crucible will not cause the crucible to crack.

[0059] Step S102, slow cooling stage;

[0060] The crucible mold 1 is cooled by circulating cooling water to slowly cool the melted crucible. Specifically, the cooling air can be turned off, and the flow rate of the circulating cooling water can be controlled to 150L / min to 300L / min, and the rotation speed of the crucible mold 1 can be controlled to 40rpm to 60rpm to achieve slow cooling of the melted crucible. At this time, the quartz crystal transformation temperature causes an increase in volume shrinkage stress. The cooling air can be turned off and the crucible can be slowly cooled by circulating cooling water to reduce the generation of shrinkage stress.

[0061] Step S103, natural cooling stage;

[0062] Cooling air is introduced into the crucible mold 1 to naturally cool the melted crucible. Specifically, the circulating cooling water can be turned off, the cooling air can be turned on, and the cooling air flow rate can be controlled to 20L / min to 30L / min, and the rotation speed of the crucible mold 1 can be controlled to 60rpm to achieve natural cooling of the melted crucible until the crucible is formed.

[0063] It should be noted that the cooling and annealing stages are performed within the melting furnace. Specifically, the rapid cooling stage (step S101), the slow cooling stage (step S102), and the natural cooling stage (step S103) can all be performed within the melting furnace. Once the crucible is melted, the cooling and annealing process can be performed without removing the crucible mold from the melting furnace. This not only effectively relieves thermal stress in the crucible, but also improves crucible production efficiency.

[0064] In some embodiments, in the rapid cooling stage of step S101, when the crucible is melted, the power supply of the electrode 5 is turned off, and cooling air is introduced into the crucible mold 1 through the air inlet main pipe 41 and the air inlet branch pipe 42. Figure 3 And, as Figure 3 and Figure 4 As shown, the flow rate of cooling air is controlled to 20 L / min by the regulating valve 411 on the air inlet main pipe 41, and the flow rate of circulating cooling water in the water cooling jacket 2 and the heat shield 3 is controlled to 300 L / min. The speed of the crucible mold 1 is controlled to 60 rpm, so that the temperature of the crucible after melting drops rapidly from 2000°C to 950°C, and the cooling time is 30 minutes. Figure 5 In the slow cooling stage of step S102, as shown in FIG. Figure 3 and Figure 4 As shown, the regulating valve 411 on the air inlet main pipe 41 is closed, and the flow rate of the circulating cooling water in the water cooling jacket 2 and the heat shield 3 is controlled to 150L / min, and the speed of the crucible mold 1 is controlled to 40rpm, so that the temperature of the crucible after melting slowly drops from 950℃ to 500℃, and the cooling time is 60min. Figure 5 In the natural cooling stage of step S103, as shown in FIG. Figure 3 and Figure 4 As shown, the circulating cooling water in the water-cooling jacket 2 and the heat shield 3 is turned off, the regulating valve 411 on the air inlet main 41 is opened, and the flow rate of the cooling air is controlled to 20 L / min, and the rotation speed of the crucible mold 1 is maintained at 60 rpm, so that the temperature of the crucible after melting drops from 500 ° C to 25 ° C, and the cooling time is 30 minutes. Figure 5 shown.

[0065] The cooling and annealing stage will be specifically explained and illustrated below using the melting of a 37-inch quartz crucible as an example.

[0066] In some embodiments, in the rapid cooling stage of step S101, when the crucible is melted, the power supply of the electrode 5 is turned off, and cooling air is introduced into the crucible mold 1 through the air inlet main pipe 41 and the air inlet branch pipe 42. Figure 3 And, as Figure 3 and Figure 4As shown, the flow rate of cooling air is controlled to 25 L / min by the regulating valve 411 on the air inlet main pipe 41, and the flow rate of circulating cooling water in the water cooling jacket 2 and the heat shield 3 is controlled to 450 L / min. The rotation speed of the crucible mold 1 is controlled to 70 rpm, so that the temperature of the crucible after melting drops rapidly from 2000°C to 850°C, and the cooling time is 30 minutes. Figure 6 In the slow cooling stage of step S102, as shown in FIG. Figure 3 and Figure 4 As shown, the regulating valve 411 on the air inlet main pipe 41 is closed, and the flow rate of the circulating cooling water in the water cooling jacket 2 and the heat shield 3 is controlled to 150L / min, and the speed of the crucible mold 1 is controlled to 40rpm, so that the temperature of the crucible after melting slowly drops from 850℃ to 400℃, and the cooling time is 60min. Figure 6 In the natural cooling stage of step S103, as shown in FIG. Figure 3 and Figure 4 As shown, the circulating cooling water in the water-cooling jacket 2 and the heat shield 3 is turned off, the regulating valve 411 on the air inlet main 41 is opened, and the flow rate of the cooling air is controlled to 25 L / min, and the rotation speed of the crucible mold 1 is maintained at 60 rpm, so that the temperature of the crucible after melting drops from 400 ° C to 25 ° C, and the cooling time is 20 minutes. Figure 6 shown.

[0067] In some embodiments, in the rapid cooling stage of step S101, when the crucible is melted, the power supply of the electrode 5 is turned off, and cooling air is introduced into the crucible mold 1 through the air inlet main pipe 41 and the air inlet branch pipe 42. Figure 3 And, as Figure 3 and Figure 4 As shown, the flow rate of cooling air is controlled to 30 L / min by the regulating valve 411 on the air inlet main pipe 41, and the flow rate of circulating cooling water in the water cooling jacket 2 and the heat shield 3 is controlled to 600 L / min. The speed of the crucible mold 1 is controlled to 80 rpm, so that the temperature of the crucible after melting drops rapidly from 2000°C to 750°C, and the cooling time is 30 minutes. Figure 7 In the slow cooling stage of step S102, as shown in FIG. Figure 3 and Figure 4 As shown, the regulating valve 411 on the air inlet main pipe 41 is closed, and the flow rate of the circulating cooling water in the water cooling jacket 2 and the heat shield 3 is controlled to 150L / min, and the speed of the crucible mold 1 is controlled to 40rpm, so that the temperature of the crucible after melting slowly drops from 750℃ to 300℃, and the cooling time is 60min. Figure 7 In the natural cooling stage of step S103, as shown in FIG. Figure 3 and Figure 4As shown, the circulating cooling water in the water-cooling jacket 2 and the heat shield 3 is turned off, the regulating valve 411 on the air inlet main 41 is opened, and the flow rate of the cooling air is controlled to 30 L / min, and the rotation speed of the crucible mold 1 is maintained at 60 rpm, so that the temperature of the crucible after melting drops from 300 ° C to 25 ° C, and the cooling time is 10 minutes. Figure 7 shown.

[0068] In the above embodiments, the prepared quartz crucibles all achieved the required operating time of more than 500 hours during crystal pulling. Therefore, the cooling annealing process for crucible melting disclosed in the embodiments of the present application can better release the thermal stress in the crucible production process, improve the strength and service life of the quartz crucible, and meet the needs during the use of vertical single crystal pulling.

[0069] like Figures 8 to 11 As shown, the present application also uses fluent and comsol simulation software to perform finite element numerical simulation analysis on the traditional cooling annealing method and the cooling annealing process of the present application. Figure 8 and Figure 9 It can be seen that the residual thermal stress of the crucible under the traditional cooling annealing method is 8.26MPa at the R corner where the residual thermal stress is concentrated, that is, the connection position between the straight wall section and the bottom wall of the crucible. Figure 10 and Figure 11 It can be seen that the residual thermal stress at the R corner where the residual thermal stress is concentrated in the crucible using the cooling annealing process of the present application is 2.78MPa. From the above example, it can be seen that the cooling annealing process of the present application can effectively release the thermal stress of the crucible during the production process, thereby improving the strength and service life of the crucible.

[0070] like Figure 3 and Figure 4 As shown, the embodiment of the present application also discloses a cooling device, which is used for a cooling annealing process of a crucible. The cooling annealing process is the cooling annealing process for melting a crucible disclosed in the above embodiment. Therefore, the cooling annealing process has all the technical effects of the above cooling annealing process, which will not be described in detail herein. The cooling device may include a water cooling component and an air cooling component 4, so that the melted crucible can be cooled by circulating cooling water through the water cooling component, and the melted crucible can be cooled by cooling air through the air cooling component 4.

[0071] In some embodiments, as Figure 3 and Figure 4As shown, the water-cooling assembly may include a water-cooling jacket 2 and a heat shield 3. The water-cooling jacket 2 can be mounted on the outside of the crucible mold 1, and the heat shield 3 is located on the open side of the crucible mold 1. Cooling channels for circulating cooling water are provided on both the heat shield 3 and the water-cooling jacket 2. This allows circulating cooling water to flow through the heat shield 3 and the water-cooling jacket 2, thereby cooling the crucible after melting. Furthermore, the heat shield 3 provides insulation and prevents dust from entering the crucible mold 1, thereby ensuring the quality of the crucible. The heat shield 3 also has an opening for inserting an electrode 5, allowing the electrode 5 to extend into the crucible mold 1 through the opening to perform high-temperature melting on the crucible mold 1.

[0072] In some embodiments, as Figure 3 As shown, the air cooling assembly 4 may include an air intake main pipe 41 and an air intake branch pipe 42 connected to the air intake main pipe 41, and there are at least two air intake branch pipes 42, that is, two, three, or more air intake branch pipes 42 may be used. When there are two air intake branch pipes 42, the air outlets 421 of the two air intake branch pipes 42 respectively extend into the crucible mold 1 and face the straight wall section and connecting section of the crucible after melting, i.e., the R angle position, so that cooling air is respectively delivered to the straight wall section and connecting section of the crucible through the air outlets 421 of the two air intake branch pipes 42, thereby ensuring the uniformity and efficiency of the cooling of the crucible after melting. In order to control the flow rate of the cooling air, a regulating valve 411 may be provided on the air intake main pipe 41, so that the cooling air flow rate can be adjusted by controlling the opening of the regulating valve 411.

[0073] In some embodiments, the main air intake pipe 41 and the branch air intake pipe 42 of the air cooling assembly 4 may employ a sandwich structure, so that the sandwich cavity between the main air intake pipe 41 and the branch air intake pipe 42 forms a sandwich cooling channel for cooling water to flow, thereby effectively preventing deformation and damage of the air cooling assembly 4 under the high temperature of the melting furnace. Of course, the main air intake pipe 41 and the branch air intake pipe 42 may also be made of high-strength stainless steel to prevent deformation and damage of the air cooling assembly 4 under high temperature.

[0074] The terms "first," "second," and so on in the specification, claims, and drawings of this application are used to distinguish between different items, not to describe a specific order. Furthermore, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements and may include steps or elements that are not listed.

[0075] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cooling annealing process for crucible melting, characterized in that: Includes steps: Melting the crucible, placing a crucible mold (1) filled with quartz sand in a melting furnace to melt the crucible; In the rapid cooling stage, cooling air is introduced into the crucible mold (1), and circulating cooling water is used to cool the crucible mold (1), so as to rapidly cool the molten crucible; In a slow cooling stage, the crucible mold (1) is cooled by the circulating cooling water to slowly cool the molten crucible; During the natural cooling stage, cooling air is introduced into the crucible mold (1) to naturally cool the molten crucible.

2. The cooling annealing process according to claim 1, characterized in that: In the rapid cooling stage, the flow rate of the cooling air is 20L / min to 30L / min, the flow rate of the circulating cooling water is 300L / min to 600L / min, and the rotation speed of the crucible mold (1) is 60rpm to 80rpm.

3. The cooling annealing process according to claim 1, characterized in that: In the step of the slow cooling stage, the flow rate of the circulating cooling water is 150L / min to 300L / min, and the rotation speed of the crucible mold (1) is 40rpm to 60rpm.

4. The cooling annealing process according to claim 1, characterized in that: In the step of the natural cooling stage, the flow rate of the cooling air is 20L / min to 30L / min, and the rotation speed of the crucible mold (1) is 60rpm.

5. The cooling annealing process according to claim 1, characterized in that: The melting crucible specifically comprises the steps of: Scraping and shaping, loading the quartz sand of different levels into the crucible mold (1) in sequence, scraping and shaping them, and placing the crucible mold (1) in a melting furnace; Melting the transparent layer, evacuating the melting furnace, and heating the quartz sand in the crucible mold (1) by starting an arc with an electrode (5) to form a transparent layer of the crucible; The bubble layer is melted, the evacuation of the melting furnace is stopped, and the quartz sand in the crucible mold (1) is heated by starting an arc through the electrode (5) to form a bubble layer of the crucible.

6. The cooling annealing process according to claim 5, characterized in that: In the step of melting the transparent layer, a vacuum pumping device is used to perform the vacuum pumping treatment on the melting furnace, and the vacuum degree of the melting furnace is controlled to be -0.085MPa to -0.095MPa by adjusting the opening of the vacuum valve of the vacuum pumping device.

7. The cooling annealing process according to claim 6, characterized in that: In the step of melting the transparent layer, the vacuuming is performed 0s to 30s after the electrode (5) starts the arc, and the duration of the vacuuming is 10min to 25min. The vacuum pump of the vacuuming equipment has a pumping speed of no more than 1200m / s. 3 / h, and the power of the electrode (5) is 1000kW to 2500kW.

8. The cooling annealing process according to claim 5, characterized in that: In the step of melting the bubble layer, the power of the electrode (5) is 2000 kW to 2500 kW, and the melting time of the melting furnace is 10 min to 20 min.

9. The cooling annealing process according to any one of claims 1 to 8, characterized in that: The rapid cooling stage, the slow cooling stage and the natural cooling stage are all carried out in the melting furnace.

10. A cooling device used in the cooling annealing process according to any one of claims 1 to 9, characterized in that: include: A water cooling assembly, the water cooling assembly comprising a water cooling jacket (2) and a heat shield (3), the water cooling jacket (2) being sleeved on the outside of the crucible mold (1), the heat shield (3) being located on the opening side of the crucible mold (1), the heat shield (3) and the water cooling jacket (2) both being provided with a cooling channel for the circulating cooling water to flow through; An air cooling component (4), the air cooling component (4) comprising an air intake main pipe (41) and an air intake branch pipe (42) connected to the air intake main pipe (41), the air intake branch pipes (42) being at least two, and the air outlets (421) of the two air intake branch pipes (42) respectively extending into the crucible mold (1) and facing the straight wall section and the connecting section of the crucible after melting, so as to respectively transport the cooling air to the straight wall section and the connecting section of the crucible through the air outlets (421) of the two air intake branch pipes (42), the air intake main pipe (41) and the air intake branch pipe (42) being provided with an interlayer cooling channel into which cooling water can be introduced, so as to prevent the air cooling component (4) from being damaged under the action of high temperature.

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