Graphite crucible dipping device and dipping method

Abstract

The invention provides an impregnation device and an impregnation method of a graphite crucible, and particularly relates to the field of material preparation. The dipping device comprises a first fixing plate, a second fixing plate and a fastener; the second fixing plate and the first fixing plate are oppositely arranged, a graphite crucible is placed between the first fixing plate and the second fixing plate, and the first fixing plate and the graphite crucible form a containing cavity; the fastener is connected with the first fixing plate and the second fixing plate and enables the first fixing plate to press the graphite crucible. The first fixing plate is provided with a ventilation connector and a pressure gauge, and the ventilation connector and the pressure gauge are communicated with the containing cavity. According to the impregnation method of the graphite crucible, the graphite crucible is immersed in the impregnation liquid, the containing cavity is subjected to air exhaust through the ventilation connector, the impregnation liquid is made to permeate into the pores of the graphite crucible more easily by means of the pressure difference between the containing cavity and the impregnation liquid, and by filling the pores of the graphite crucible, the high temperature resistance and the oxidation resistance of the graphite crucible can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the field of material preparation, and in particular to an impregnation device and an impregnation method for a graphite crucible. Background Art

[0002] Graphite crucible plays a key role in the smelting field due to its good high temperature resistance, thermal conductivity, chemical stability and resistance to rapid cooling and heating. It is widely used in the smelting of special alloy steels, the melting of non-ferrous metals and their alloys, and the preparation of high-purity metals and semiconductor materials. Graphite crucible not only provides an efficient smelting environment, but also ensures chemical stability and product quality during the smelting process. Although graphite crucibles have good high temperature resistance and thermal conductivity, they are more susceptible to oxidation in high temperature applications, which will reduce their performance and service life. Summary of the invention

[0003] In view of the above shortcomings of the prior art, the present invention provides an impregnation device and an impregnation method for a graphite crucible, so as to slow down the oxidation rate of the graphite crucible during use and increase the service life of the graphite crucible.

[0004] To achieve the above-mentioned purpose and other related purposes, the present invention provides an impregnation device for a graphite crucible, the impregnation device comprising a first fixing plate, a second fixing plate and a fastener; the second fixing plate is arranged opposite to the first fixing plate, the first fixing plate and the second fixing plate are used to place the graphite crucible between them, and the first fixing plate and the graphite crucible form a containing cavity; the fastener connects the first fixing plate and the second fixing plate, and enables the first fixing plate to press the graphite crucible; wherein, a ventilation interface and a pressure gauge are arranged on the first fixing plate, and the ventilation interface and the pressure gauge are respectively connected to the containing cavity.

[0005] In an example of the present invention, the fastener includes a screw and a nut, and the first fixing plate and the second fixing plate are both provided with through holes matching the screw, and the screw passes through the second fixing plate and the first fixing plate in turn and is threadedly connected to the nut.

[0006] In one example of the present invention, the ventilation interface includes a pressurization interface for inflating the accommodating chamber and a decompression interface for evacuating the accommodating chamber, and both the pressurization interface and the decompression interface are provided with valves for controlling the passage of gas.

[0007] In one example of the present invention, the pressure gauge includes a positive pressure gauge and a negative pressure gauge, the positive pressure gauge and the negative pressure gauge are respectively connected to the accommodating cavity, and the positive pressure gauge and the negative pressure gauge are both provided with valves for controlling the passage of gas.

[0008] In an example of the present invention, a sealing ring is arranged between the first fixing plate and the graphite crucible, an annular groove is arranged on the side of the first fixing plate facing the graphite crucible, the annular groove is coaxial with the graphite crucible, and the sealing ring is arranged in the annular groove.

[0009] The present invention also provides a method for impregnating a graphite crucible, comprising the following steps:

[0010] Provide an impregnation device for the graphite crucible, and assemble the graphite crucible with the impregnation device;

[0011] immersing the graphite crucible in an impregnation liquid;

[0012] The containing chamber is evacuated and the pressure is maintained for a period of time, the pressure of the containing chamber is restored to atmospheric pressure, and the graphite crucible is removed;

[0013] The impregnated graphite crucible is dried.

[0014] In one example of the present invention, before immersing the graphite crucible in the immersion liquid, the process also includes: inflating the containing chamber to increase the pressure of the containing chamber to 0.5-0.8 MPa and maintaining it for 10-15 minutes, and restoring the pressure of the containing chamber to atmospheric pressure.

[0015] In an example of the present invention, when the containing chamber is evacuated and the pressure is maintained, the containing chamber is evacuated and the pressure maintenance time is 16 to 20 hours.

[0016] In an example of the present invention, the impregnation liquid is a mixed solution of water glass and silica sol, and the mass ratio of the water glass to the silica sol is 1:1 to 1.5:1.

[0017] In an example of the present invention, the drying temperature of the graphite crucible is 60-120° C., and the drying time is 5-8 hours.

[0018] The impregnation device of the graphite crucible of the present invention has a graphite crucible placed between a first fixing plate and a second fixing plate, and the first fixing plate and the second fixing plate are connected by fasteners, so that the first fixing plate presses the graphite crucible and forms a receiving chamber with the graphite crucible, and a vent interface and a pressure gauge connected to the receiving chamber are provided on the first fixing plate. When impregnating the graphite crucible, the graphite crucible and the impregnation device are assembled and immersed in the impregnation liquid, and the receiving chamber is evacuated through the vent interface, and the pressure difference between the receiving chamber and the impregnation liquid is used to make the impregnation liquid penetrate into the pores of the graphite crucible, and by filling the pores of the graphite crucible, its high temperature resistance and oxidation resistance can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a structural schematic diagram of an impregnation device for a graphite crucible of the present invention in one embodiment;

[0021] Figure 2 FIG. 1 is a flow chart of an impregnation method for a graphite crucible according to an embodiment of the present invention.

[0022] Component number description

[0023] 10. Graphite crucible; 11. Accommodating chamber; 100. First fixed plate; 110. Ventilation interface; 111. Pressurization interface; 112. Decompression interface; 120. Pressure gauge; 121. Positive pressure gauge; 122. Negative pressure gauge; 130. Lifting ring; 200. Second fixed plate; 300. Fastener; 310. Screw; 320. Nut; 400. Sealing ring; 500. Immersing liquid; 600. Container; 610. Leg. DETAILED DESCRIPTION

[0024] The following is an explanation of the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the features in the following embodiments and the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are usually carried out under conventional conditions or according to the conditions recommended by the manufacturers.

[0025] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" etc. used in this specification are only for the convenience of description and are not intended to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be regarded as the scope of implementation of the present invention.

[0026] See also Figure 1The present invention provides an impregnation device for a graphite crucible 10, which includes a first fixing plate 100, a second fixing plate 200 and a fastener 300; the second fixing plate 200 is arranged opposite to the first fixing plate 100, the graphite crucible 10 is placed between the first fixing plate 100 and the second fixing plate 200, and the first fixing plate 100 and the graphite crucible 10 form a receiving cavity; the fastener 300 connects the first fixing plate 100 and the second fixing plate 200, and enables the first fixing plate 100 to press the graphite crucible 10. The first fixing plate 100 is provided with a vent interface 110 and a pressure gauge 120, and the vent interface 110 and the pressure gauge 120 are respectively connected to the receiving cavity 11. When the graphite crucible 10 is impregnated, the graphite crucible 10 is immersed in the impregnation liquid 500, and the accommodating cavity 11 is evacuated through the ventilation interface 110. The pressure difference between the accommodating cavity 11 and the impregnation liquid 500 is used to make the impregnation liquid 500 penetrate into the pores of the graphite crucible 10. By filling the pores of the graphite crucible 10, its high temperature resistance and oxidation resistance can be significantly improved, and the service life of the graphite crucible 10 can be extended.

[0027] See also Figure 1 In one embodiment, the fastener 300 includes a screw 310 and a nut 320. The first fixing plate 100 and the second fixing plate 200 are both provided with through holes matching the screw 310. The screw 310 passes through the second fixing plate 200 and the first fixing plate 100 in sequence and is threadedly connected with the nut 320. In this embodiment, the impregnation device includes eight fasteners 300, and the eight fasteners 300 are evenly distributed along the circumference of the first fixing plate 100 and the second fixing plate 200. In other embodiments, the number of fasteners 300 may also be seven, ten or other numbers. The number of fasteners 300 is not limited in this application. It is adaptively adjusted according to actual needs to meet the requirements that the first fixing plate 100 is fixedly connected to the second fixing plate 200 and the first fixing plate 100 presses the graphite crucible 10, and the airtightness between the first fixing plate 100 and the graphite crucible 10 is good. The sizes of the first fixing plate 100 and the second fixing plate 200 are adaptively adjusted according to the requirements. For example, the thickness of the first fixing plate 100 and the second fixing plate 200 is 10-15 mm, such as 10 mm, 13 mm or 15 mm.

[0028] See also Figure 1In one embodiment, the vent interface 110 includes a pressurizing interface 111 for inflating the accommodating chamber 11 and a decompression interface 112 for degassing the accommodating chamber 11. The pressurizing interface 111 and the decompression interface 112 are respectively connected to the accommodating chamber 11, and valves for controlling the passage of gas are provided on the pressurizing interface 111 and the decompression interface 112. The pressure gauge 120 includes a positive pressure gauge 121 and a negative pressure gauge 122. The positive pressure gauge 121 and the negative pressure gauge 122 are respectively connected to the accommodating chamber 11, and valves for controlling the passage of gas are provided on the positive pressure gauge 121 and the negative pressure gauge 122. When degassing the accommodating chamber 11, the valves on the decompression interface 112 and the valves on the negative pressure gauge 122 are opened, and the valves on the pressurizing interface 111 and the positive pressure gauge 121 are closed; when pressurizing the accommodating chamber 11, the valves on the pressurizing interface 111 and the positive pressure gauge 121 are opened, and the valves on the decompression interface 112 and the negative pressure gauge 122 are closed. The positive pressure gauge 121 and the negative pressure gauge 122 are of commonly used specifications in the field. For example, the positive pressure gauge 121 has a range of 0 to 1.6 MPa, and the negative pressure gauge 122 is a 0.4-level high-precision vacuum gauge with a range of 0 to 1 MPa.

[0029] See also Figure 1 In one embodiment, in order to enhance the airtightness of the connection between the first fixing plate 100 and the graphite crucible 10, a sealing ring 400 is provided between the first fixing plate 100 and the graphite crucible 10. Specifically, an annular groove is provided on the side of the first fixing plate 100 facing the graphite crucible 10, and the annular groove is coaxial with the graphite crucible 10. The sealing ring 400 is arranged in the annular groove to prevent the first fixing plate 100 and the second fixing plate 200 from being offset when being fastened. In this embodiment, the sealing ring 400 is made of silicone. In other embodiments, the sealing ring 400 can also be made of other elastic materials to meet the sealing requirements.

[0030] See also Figure 1 and Figure 2 The present invention also provides a method for impregnating a graphite crucible 10, comprising the following steps:

[0031] S1, providing an impregnation device, and assembling the graphite crucible 10 with the impregnation device;

[0032] S2, immersing the graphite crucible 10 in the immersion liquid 500;

[0033] S3, after evacuating the containing chamber 11 and maintaining the pressure for a period of time, the pressure of the containing chamber 11 is restored to atmospheric pressure, and the graphite crucible 10 is removed;

[0034] S4, drying the impregnated graphite crucible 10.

[0035] See also Figure 1 and Figure 2In step S1, in one embodiment, the impregnation device includes a first fixing plate 100, a second fixing plate 200 and a fastener 300. The second fixing plate 200 is arranged opposite to the first fixing plate 100. The graphite crucible 10 is placed between the first fixing plate 100 and the second fixing plate 200. The first fixing plate 100 and the graphite crucible 10 form a receiving cavity. The fastener 300 connects the first fixing plate 100 and the second fixing plate 200, and makes the first fixing plate 100 press the graphite crucible 10 to ensure good air tightness between the first fixing plate 100 and the graphite crucible 10. The first fixing plate 100 is provided with a vent interface 110 and a pressure gauge 120, and the vent interface 110 and the pressure gauge 120 are respectively connected to the receiving cavity 11.

[0036] See also Figure 1 and Figure 2 In step S2, when the graphite crucible 10 is impregnated, the graphite crucible 10 is completely immersed in the impregnation liquid 500, for example, the liquid level of the impregnation liquid 500 is 1 cm above the first fixed plate 100. In one embodiment, the combination of the graphite crucible 10 and the impregnation device is immersed in a container 600 containing the impregnation liquid 500. The type of the container 600 for containing the impregnation liquid 500 is not limited here, and it is adaptively adjusted according to actual needs. Exemplarily, the container 600 is a drum made of steel, the wall thickness of the drum is 3 mm, the diameter of the drum is 2 m, the height of the drum is 1.2 m, and a 0.3 m support leg 610 is fixedly provided at the bottom of the drum. In this embodiment, in order to facilitate the transfer of the graphite crucible 10, a hanging ring 130 is provided on the side of the first fixed plate 100 away from the graphite crucible 10. When the graphite crucible 10 is transferred, the lifting device is connected to the lifting ring 130 to lift and transfer the graphite crucible 10 .

[0037] In the present application, the impregnation liquid 500 is a mixed solution of water glass and silica sol. Furthermore, the mass ratio of water glass to silica sol is 1:1 to 1.5:1, such as 1:1, 1.2:1, 1.4:1 or 1.5:1. Water glass and silica sol have the following characteristics: the main components of water glass after hardening are silica gel and silicon oxide, which has high adhesion and strength and good acid resistance, and the silica mesh skeleton formed by hardening of water glass has good high temperature resistance. The colloidal particles of silica sol are small in size and have high dispersibility. Its colloidal properties and the charge on the surface of the particles make it difficult for the particles to aggregate, and silica sol has good high temperature resistance and good adhesion; the high permeability of silica sol enables it to penetrate into the pores of porous materials, thereby improving the impregnation effect; in addition, silica sol has excellent chemical inertness and is not easy to react with other substances. The pores of the graphite crucible 10 are filled with a mixed solution of water glass and silica sol as the impregnation liquid 500, which combines the high viscosity and bonding force of water glass with the small particle size and high permeability of silica sol, providing enhanced bonding, improved water resistance and high temperature resistance, while possibly improving the mechanical strength and corrosion resistance of the material, and may also optimize the curing performance, enhance environmental stability, adjust the thermal expansion coefficient, and improve the pore filling efficiency. Furthermore, water glass and silica sol are cheap and suitable for large-scale industrial applications.

[0038] See also Figure 1 and Figure 2 In step S3, in one embodiment, the vent interface 110 of the impregnation device includes a pressurization interface 111 for inflating the accommodating chamber 11 and a decompression interface 112 for evacuating the accommodating chamber 11. The pressurization interface 111 and the decompression interface 112 are respectively connected to the accommodating chamber 11, and valves for controlling the passage of gas are provided on the pressurization interface 111 and the decompression interface 112. The pressurization interface 111 is connected to the compressed gas, and the decompression interface 112 is connected to the vacuum pump group. Further, in order to strengthen the sealing of the connection between the first fixed plate 100 and the crucible 10, a sealing ring 400 is provided between the first fixed plate 100 and the graphite crucible 10.

[0039] Before the impregnation device is immersed in the impregnation liquid 500, the process also includes: ventilating the accommodating chamber 11 through the pressurizing interface 111, raising the pressure of the accommodating chamber 11 to 0.5-0.8MPa and maintaining it for 10-15min, and restoring the pressure of the accommodating chamber 11 to atmospheric pressure. For example, the pressure of the accommodating chamber 11 can be raised to 0.5MPa, 0.6MPa, 0.7MPa or 0.8MPa, and the holding time can be 10min, 12min, 14min or 15min. Increasing the pressure of the accommodating chamber 11 can not only clean the pores on the wall of the graphite crucible 10 to prevent the accumulation of impurities and gases, but also dredge the pores of the graphite crucible 10, so that the impregnation liquid 500 can flow better in the wall of the graphite crucible 10. The present application does not limit the type of compressed gas, and the compressed gas can be any gas that is not in contact with the graphite crucible 10. Furthermore, the airtightness of the connection between the first fixed plate 100 and the accommodating chamber 11 can be detected in this process. Exemplarily, soapy water can be used for testing. Specifically, soapy water is applied to the connection between the first fixing plate 100 and the graphite crucible 10. If no bubbles are generated by the soapy water, it means that the air tightness is good. If bubbles are generated, it means that the air tightness is poor. The connection between the first fixing plate 100 and the graphite crucible 10 can be strengthened by adjusting the fastener 300, or the sealing ring 400 between the first fixing plate 100 and the graphite crucible 10 can be replaced to enhance the air tightness.

[0040] When the graphite crucible 10 is impregnated, the accommodating chamber 11 is evacuated through the decompression interface 112, and the valve on the decompression interface 112 is closed to maintain the pressure. The pressure maintenance time can be 16h, 18h or 20h. In one embodiment, the vacuum degree of the accommodating chamber 11 is 0.098MPa and the valve on the decompression interface 112 is closed to maintain the pressure. In order to ensure the impregnation effect of the graphite crucible 10, the pressure in the accommodating chamber 11 should be observed during the impregnation process. If the vacuum degree of the accommodating chamber 11 drops to 0.01MPa, the accommodating chamber 11 is evacuated again to a vacuum degree of 0.098MPa. After the pressure maintenance is completed, the combination of the impregnation device and the graphite crucible 10 is taken out, and the valve on the decompression interface 112 is opened to allow air to slowly enter the accommodating chamber 11 until the pressure in the accommodating chamber 11 is consistent with the atmospheric pressure, and the impregnation device is removed. The vacuum pump group is a commonly used device in the field. For example, the vacuum pump group includes a two-stage 7.5KW Roots pump, a 7.5KW sliding valve pump, a vacuum bellows and a chuck quick-release clamp. The decompression interface 112 and the vacuum pump group are assembled according to conventional means in the field, which will not be described here. After the impregnation is completed, it can be observed that the impregnation liquid seeps out from the inner wall of the graphite crucible 10, indicating that the impregnation effect of the graphite crucible 10 is good.

[0041] In step S4, the graphite crucible 10 is transferred to a drying furnace for drying. The drying effect is preferably that the impregnation liquid on the wall of the graphite crucible is dried and solidified. If the drying temperature is too low, the solidification effect of water glass and silica sol is not good; if the drying temperature is too high, bubbles will be generated on the inner and outer walls of the graphite crucible during the drying process, and it is easy to dry unevenly. Therefore, too high and too low drying temperatures will affect the performance of the graphite crucible 10 after impregnation. Exemplarily, the drying temperature of the graphite crucible 10 is 60 to 120°C, such as 60°C, 80°C, 100°C or 120°C, and the drying time is 5 to 8h, such as 5h, 6h, 7h or 8h. When drying the graphite crucible 10, a drying furnace commonly used in the art is selected. Exemplarily, the drying furnace uses a trolley-type resistance furnace, and the power configuration of the resistance furnace is 128KW.

[0042] The technical scheme of the present invention is described in detail below through several specific examples. Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products, or can be prepared by conventional methods in the art, and the instruments used in the examples are all commercially available.

[0043] Example 1

[0044] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.5Mpa and maintain the pressure for 15 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 16 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 60°C for 8 hours. In this embodiment, the mass ratio of water glass to silica sol is 1:1.

[0045] Example 2

[0046] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.7Mpa and maintain the pressure for 12 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 16 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 65°C for 8 hours. In this embodiment, the mass ratio of water glass to silica sol is 1:1.

[0047] Example 3

[0048] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.6Mpa and maintain the pressure for 13 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 17 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 120°C for 5 hours. In this embodiment, the mass ratio of water glass to silica sol is 1.1:1.

[0049] Example 4

[0050] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.8Mpa and maintain the pressure for 10 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 16.5 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 80°C for 7 hours. In this embodiment, the mass ratio of water glass to silica sol is 1.1:1.

[0051] Example 5

[0052] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.8Mpa and maintain the pressure for 11 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 17 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 90°C for 6 hours. In this embodiment, the mass ratio of water glass to silica sol is 1.2:1.

[0053] Example 6

[0054] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.7Mpa and maintain the pressure for 12 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 17 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 85°C for 7 hours. In this embodiment, the mass ratio of water glass to silica sol is 1.2:1.

[0055] Example 7

[0056] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.8Mpa and maintain the pressure for 10 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 16 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 90°C for 5.5 hours. In this embodiment, the mass ratio of water glass to silica sol is 1:1.

[0057] Example 8

[0058] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.8Mpa and maintain the pressure for 11 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 18 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 100°C for 6 hours. In this embodiment, the mass ratio of water glass to silica sol is 1.3:1.

[0059] Example 9

[0060] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.7Mpa and maintain the pressure for 12 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 19 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 100°C for 6 hours. In this embodiment, the mass ratio of water glass to silica sol is 1.4:1.

[0061] Example 10

[0062] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.6Mpa and maintain the pressure for 14 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 19 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 70°C for 7 hours. In this embodiment, the mass ratio of water glass to silica sol is 1.4:1.

[0063] Embodiment 11

[0064] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.7Mpa and maintain the pressure for 12 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 18 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 110°C for 5.5 hours. In this embodiment, the mass ratio of water glass to silica sol is 1.5:1.

[0065] Example 12

[0066] Assemble the graphite crucible with the impregnation device, introduce compressed air into the containing chamber until the pressure reaches 0.8Mpa and maintain the pressure for 10 minutes. Immerse the graphite crucible in a mixed solution of water glass and silica sol, evacuate the containing chamber and maintain it for 20 hours. After the impregnation is completed, take out the graphite crucible with the impregnation device, restore the pressure of the containing chamber to atmospheric pressure, remove the graphite crucible, and dry it at 120°C for 5 hours. In this embodiment, the mass ratio of water glass to silica sol is 1.5:1.

[0067] The size (outer diameter*inner diameter*height) of the graphite crucible selected in Examples 1 to 12 is 1300 mm*970 mm*760 mm. The graphite crucible impregnated in Examples 1 to 12 is used in metal smelting. In actual production, the wall thickness of the graphite crucible is less than 100 mm, which does not meet the use requirements. The use conditions and service life of the graphite crucible are shown in Table 1:

[0068] Table 1: Use conditions and service life of impregnated graphite crucibles and unimpregnated graphite crucibles of Examples 1 to 12:

[0069]

[0070]

[0071] It can be seen from Table 1 that the service life of the impregnated graphite crucible is greatly improved and is suitable for metal smelting.

[0072] In the impregnation device for graphite crucible of the present invention, a graphite crucible is placed between a first fixed plate and a second fixed plate, and the first fixed plate and the second fixed plate are connected by fasteners, so that the first fixed plate presses the graphite crucible and forms a receiving chamber with the graphite crucible, and a ventilation interface and a pressure gauge connected to the receiving chamber are provided on the first fixed plate. When impregnating the graphite crucible, the graphite crucible and the impregnation device are assembled and immersed in the impregnation liquid, and the receiving chamber is evacuated through the ventilation interface, and the pressure difference between the receiving chamber and the impregnation liquid is used to make the impregnation liquid penetrate into the pores of the graphite crucible. By filling the pores of the graphite crucible, its high temperature resistance and oxidation resistance can be significantly improved. Therefore, the present invention effectively overcomes some practical problems in the prior art and has a high utilization value and use significance.

[0073] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A graphite crucible impregnation device, characterized in that: The impregnation device comprises: a first fixing plate; A second fixing plate is arranged opposite to the first fixing plate, a graphite crucible is placed between the first fixing plate and the second fixing plate, and the first fixing plate and the graphite crucible form a containing cavity; A fastener, connecting the first fixing plate and the second fixing plate, and allowing the first fixing plate to press the graphite crucible; Wherein, a ventilation interface and a pressure gauge are arranged on the first fixing plate, and the ventilation interface and the pressure gauge are communicated with the accommodating cavity respectively.

2. The impregnation device according to claim 1, characterized in that The fastener includes a screw and a nut. The first fixing plate and the second fixing plate are both provided with through holes matching the screw. The screw passes through the second fixing plate and the first fixing plate in sequence and is threadedly connected with the nut.

3. The impregnation device according to claim 1, characterized in that The ventilation interface includes a pressurization interface for inflating the accommodating cavity and a decompression interface for evacuating the accommodating cavity. Both the pressurization interface and the decompression interface are provided with valves for controlling the passage of gas.

4. The impregnation device according to claim 1, characterized in that The pressure gauge comprises a positive pressure gauge and a negative pressure gauge, the positive pressure gauge and the negative pressure gauge are respectively connected to the accommodating cavity, and the positive pressure gauge and the negative pressure gauge are both provided with valves for controlling the passage of gas.

5. The impregnation device according to claim 1, characterized in that A sealing ring is arranged between the first fixing plate and the graphite crucible, an annular groove is arranged on the side of the first fixing plate facing the graphite crucible, the annular groove is coaxial with the graphite crucible, and the sealing ring is arranged in the annular groove.

6. A method for impregnating a graphite crucible, characterized in that: The steps include: Provide an impregnation device for a graphite crucible according to any one of claims 1 to 5, and assemble the graphite crucible with the impregnation device; immersing the graphite crucible in an impregnation liquid; The containing chamber is evacuated and the pressure is maintained for a period of time, the pressure of the containing chamber is restored to atmospheric pressure, and the graphite crucible is removed; The impregnated graphite crucible is dried.

7. The impregnation method according to claim 6, characterized in that Before immersing the graphite crucible in the immersion liquid, the method further includes inflating the containing chamber to raise the pressure of the containing chamber to 0.5-0.8 MPa and maintaining the pressure for 10-15 minutes, and restoring the pressure of the containing chamber to atmospheric pressure.

8. The impregnation method according to claim 6, characterized in that When the containing chamber is evacuated and the pressure is maintained, the containing chamber is evacuated and the pressure maintenance time is 16 to 20 hours.

9. The impregnation method according to claim 6, characterized in that The impregnation liquid is a mixed solution of water glass and silica sol, and the mass ratio of the water glass to the silica sol is 1:1 to 1.5:

1.

10. The impregnation method according to claim 6, characterized in that The drying temperature of the graphite crucible is 60-120° C., and the drying time is 5-8 hours.

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