Plasma high-temperature furnace for material purification
The plasma high-temperature furnace uses thermodynamic principles to evaporate impurities, which solves the problem that traditional purification methods are difficult to achieve ultra-high purity and environmental pollution, and achieves efficient and environmentally friendly material purification effects.
Patent Information
- Application Number
- CN202510736647.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-04
- Publication Date
- 2025-07-11
AI Technical Summary
Traditional purification methods are difficult to achieve ultra-high purity, and there are problems with environmental pollution risks and high equipment costs.
A plasma high-temperature furnace is used to generate high-temperature arc heating through a plasma torch, and the impurities are evaporated using thermodynamic principles to avoid chemical reactions. The graphite crucible and refractory layer are used to maintain temperature and pressure equilibrium, and the shell is cooled for double-layer structure.
It realizes efficient and environmentally friendly material purification, simplifies processes, reduces equipment complexity and maintenance costs, and avoids the introduction of additional impurities in chemical reagents.
Smart Images
Figure CN120292873A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of plasma technology, and particularly to a plasma high-temperature furnace for material purification. Background Art
[0002] High-purity materials are crucial for ensuring the performance and safety of products, significantly improving the performance and reliability of equipment, and reducing the impact of impurities on material properties. With the progress of technology, the requirements for material purity are getting higher and higher, and the market demand is also increasing continuously. It has broad application prospects in many high-end fields such as semiconductor manufacturing, optical materials and superconductors, aerospace, biomedicine, etc. For example, 6N-grade silicon is used in the manufacture of high-performance integrated circuits and electronic devices in the semiconductor industry, and 6N-grade ultra-pure copper is also widely used in electronics and semiconductor manufacturing.
[0003] Traditional purification methods such as chemical precipitation method, solvent extraction method, etc. usually involve a large amount of chemical reagents, which may cause environmental pollution problems and may not be able to completely remove some trace impurities, especially for application fields with extremely high purity requirements. Physical methods such as flotation, screening, etc. are often used for preliminary purification and are difficult to achieve ultra-high purity. In addition, some physical methods may damage the microstructure of materials during the purification process, affecting the final properties of the materials.
[0004] High-temperature purification technology can significantly improve the purity of materials in a short time, especially for those materials with extremely high purity requirements. Compared with chemical purification methods, high-temperature purification technology reduces the use of chemical reagents and reduces the risk of environmental pollution. It utilizes the differences in physical and chemical properties of different elements or compounds at high temperatures (such as significant differences in the volatilization temperature, melting point, vapor pressure, etc. of different elements). Some impurities will volatilize, sublime or melt, while the pure material remains unchanged or undergoes specific reactions, thereby realizing the separation of impurities and materials. It can be widely applied to the production processes of metals, semiconductors, graphite and other materials.
[0005] Since high-temperature purification usually requires extremely high temperatures, the production cost is high. Special equipment that can withstand extremely high temperatures and has good control accuracy is required, the operating environment requirements are strict, and the actual operation faces challenges in terms of energy consumption and equipment cost, etc. Summary of the Invention
[0006] The present invention provides a plasma high-temperature furnace for material purification, aiming at that the purification process does not involve complex chemical reactions, only needs to provide appropriate heat, relies on thermodynamic principles, avoids the use of chemical reagents, does not introduce additional chemical impurities or generate waste liquid, and reduces the risk of environmental pollution.
[0007] The present invention is realized by the following technical solutions: A plasma high-temperature furnace for material purification, comprising a plasma torch, a furnace body, a furnace body fixing seat, and a crucible. The furnace body is connected to the furnace body fixing seat. The furnace body includes a housing, a lining, a refractory layer, and a heat-insulating layer. The lining, the refractory layer, and the heat-insulating layer are sequentially located inside the housing from the inside to the outside. An exhaust pipe is connected to the top of the furnace body; The crucible is located at the lower part of the housing, and the crucible is located in the inner cavity at the lower part of the refractory layer. The plasma torch is connected to the bottom of the housing; The inside of the lining is hollow, and the bottom end of the lining abuts against the crucible. The top end of the lining communicates with the exhaust pipe. There is a gap channel between both the lining and the crucible and the refractory layer, and the gap channel communicates with the exhaust pipe; A ring cavity communicating with the outlet of the plasma is opened at the bottom of the housing. Air holes are opened on the side wall of the ring cavity, and the air holes communicate with the gap channel.
[0008] Compared with the prior art, this solution has the following advantages and beneficial effects: In this solution, a DC high-temperature arc is generated by the plasma torch to heat the crucible. The impurity components of the material to be purified in the crucible are rapidly evaporated under the action of the high temperature of the plasma to form impurity vapor, and the impurity vapor is then discharged through the exhaust pipe, so as to achieve the purpose of material purification. The impurity vapor generated in this solution enters the exhaust channel through the lining and is then discharged, leaving behind a material with high purity. The whole process does not involve complex chemical reactions, only requires the provision of appropriate heat, relies on the principles of thermodynamics, avoids the use of chemical reagents, does not introduce additional chemical impurities or generate waste liquid, reduces the risk of environmental pollution, and can simplify the process, reducing the complexity and maintenance cost of the equipment.
[0009] In addition, there is a gap channel between both the lining and the crucible and the refractory layer in this solution, which can maintain the pressure balance inside the entire furnace body during the process of high-temperature combustion of the plasma, thus ensuring safety. The refractory layer in this solution has fire resistance, while the heat-insulating layer has a heat-insulating effect to ensure the heating temperature, thus facilitating the rapid purification of materials.
[0010] Further, the housing includes an inner layer housing and an outer layer housing arranged coaxially. There is a water storage space between the inner layer housing and the outer layer housing. The housing is provided with a water inlet pipe and a water outlet pipe communicating with the water storage space. The water inlet pipe is located at the lower part of the housing, and the water outlet pipe is located at the upper part of the housing.
[0011] Beneficial effects: In this solution, the outer shell is a double-layer structure composed of an inner shell and an outer shell. Water is injected into the water storage space between the inner shell and the outer shell through the water inlet pipe to cool the entire furnace body, avoiding damage to the furnace body due to excessive temperature. In this solution, the water that enters the water storage space from the water inlet pipe finally discharges from the water outlet pipe, thus facilitating the circulation of the cooling water in the water storage space and ensuring the effectiveness of cooling the furnace body.
[0012] Furthermore, a pressing plate is provided inside the outer shell. The pressing plate is located above the refractory layer and the insulation layer. A through hole is opened in the middle of the pressing plate. A stepped engaging portion is provided at the upper part of the inner lining. The inner lining passes through the through hole of the pressing plate, and the stepped engaging portion at the upper part of the inner lining abuts against the top of the pressing plate.
[0013] Beneficial effects: The setting of the pressing plate in this solution facilitates the installation and positioning of the inner lining. By providing a stepped engaging portion at the upper part of the inner lining, the inner lining can be positioned on the pressing plate through the stepped engaging portion at its upper part, providing a supporting effect on the inner lining and making the disassembly and assembly of the inner lining more convenient and fast.
[0014] Furthermore, an annular hole is opened in the pressing plate.
[0015] Beneficial effects: The annular hole opened in the pressing plate in this solution can accelerate the speed of gas discharge.
[0016] Furthermore, the outer shell includes a fixed outer shell and a detachable outer shell. The bottom end of the fixed outer shell is detachably connected coaxially with the top end of the detachable outer shell. The fixed outer shell is connected to the furnace body fixing seat. The detachable outer shell is suspended. The crucible is located inside the detachable outer shell.
[0017] Beneficial effects: In this solution, the outer shell is divided into a fixed outer shell and a detachable outer shell. In this way, when placing the material to be purified in the crucible, it is only necessary to detach the detachable outer shell from below to place or remove the material in the crucible, which is convenient to operate.
[0018] Furthermore, a support plate is connected to the bottom of the fixed outer shell and located inside it. A through hole is opened in the middle of the support plate. The bottom of the inner lining can pass through the through hole of the support plate and abut against the crucible. Communication holes are opened in the support plate for communicating the gap channels above and below the support plate.
[0019] Beneficial effects: The setting of the support plate in this solution can support the insulation layer and the refractory layer located inside the fixed outer shell. In this way, after the detachable outer shell is opened when putting the material into the crucible or taking the material out of the crucible, the insulation layer and the refractory layer can be prevented from falling under the support of the support plate, and this method does not require additional support structures and is convenient to use.
[0020] Further, a stepped engaging portion is provided at the lower part of the inner liner, and the stepped engaging portion at the lower part of the inner liner abuts against the top of the support plate.
[0021] Beneficial effects: In this solution, a stepped engaging portion is provided at the lower part of the inner liner, so that it can cooperate with the support plate, enabling the support plate to support the inner liner and maintaining the stability of the inner liner.
[0022] Further, the fixed outer shell includes an upper outer shell and a lower outer shell, and the bottom end of the upper outer shell and the top end of the lower outer shell are detachably connected coaxially.
[0023] Beneficial effects: In this solution, the fixed outer shell is composed of an upper outer shell and a lower outer shell, which divides the fixed outer shell into upper and lower parts, facilitating the installation of the heat insulation layer and the refractory layer.
[0024] Further, both the crucible and the inner liner are made of graphite material.
[0025] Beneficial effects: In this solution, the crucible and the inner liner are made of graphite material, which has strong high-temperature resistance.
[0026] Further, the material of the refractory layer is made by stacking refractory bricks or prefabricating and forming alumina hollow spheres.
[0027] Beneficial effects: In this solution, the refractory layer has good refractory effect, is convenient, has low cost, is easy to process, and is convenient to stack and install in the outer shell. Description of the Drawings
[0028] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not constitute a limitation to the embodiments of the present invention. In the drawings: Figure 1 It is a longitudinal sectional view of Embodiment 1 of a plasma high-temperature furnace for material purification according to the present invention; Figure 2 is Figure 1 a partial enlarged view of A in Figure 3 It is a longitudinal sectional view of Embodiment 2 of a plasma high-temperature furnace for material purification according to the present invention.
[0029] Marks in the drawings and corresponding component names: Plasma torch 1, plasma torch flange 101, furnace body fixing seat 2, furnace body 3, crucible 4, inner liner 5, refractory layer 6, heat insulation layer 7, outer shell 8, outer shell bottom flange 80, fixed outer shell 81, upper outer shell 811, lower outer shell 812, detachable outer shell 82, exhaust pipe 9, furnace cover 10, water inlet pipe 11, water outlet pipe 12, support plate 13, detachable outer shell flange 14, fixed outer shell flange 15, annular cavity 16, air hole 17, pressing plate 18. Detailed Embodiments
[0030] To make the objectives, technical solutions, and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings. The illustrative embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.
[0031] Embodiment 1 As Figure 1 - Figure 2 shown, Embodiment 1 of the present invention provides a plasma high-temperature furnace for material purification, including a plasma torch 1, a furnace body 3, a furnace body fixing seat 2, and a crucible 4. The furnace body 3 is connected to the furnace body fixing seat 2, and the furnace body fixing seat 2 is welded into one body using a carbon steel bracket.
[0032] In this embodiment, the furnace body 3 includes an outer shell 8, a lining 5, a refractory layer 6, and a heat insulation layer 7. The lining 5, the refractory layer 6, and the heat insulation layer 7 are sequentially located inside the outer shell 8 from the inside to the outside. An exhaust pipe 9 is connected to the top of the furnace body 3. In this embodiment, the top of the outer shell 8 is connected with a furnace cover 10. A sealing ring is provided between the furnace cover 10 and the top of the outer shell 8. The exhaust pipe 9 is fixed to the furnace cover 10 through a flange and bolts, and one end of the exhaust pipe 9 is located inside the outer shell 8.
[0033] In this embodiment, the plasma torch 1 generates a high-temperature plasma jet by means of direct current arc discharge, with a power requirement of ≥100 kW and an adjustable working medium, and its purpose is to heat the crucible 4, and the heating temperature of the crucible 4 > 2800 °C.
[0034] The crucible 4 is located at the lower part of the outer shell 8 and is located in the inner cavity at the lower part of the refractory layer 6. The plasma torch 1 is connected to the bottom of the outer shell 8. Combining Figure 2 shown, in this embodiment, an outer shell bottom flange 80 is fixedly connected to the bottom of the outer shell 8, and a plasma torch flange 101 is fixedly connected to the top end of the plasma torch 1. The plasma torch flange 101 and the outer shell bottom flange 80 are connected by bolts, thereby realizing the connection between the plasma torch 1 and the outer shell 8. In this embodiment, in order to ensure the sealing of the connection, a sealing groove is provided between the plasma torch flange 101 and the outer shell bottom flange 80, and a sealing ring is arranged in the sealing groove, so that the two are hermetically connected.
[0035] As Figure 1 shown, there are clearance channels between both the lining 5 and the crucible 4 and the refractory layer 6, and the clearance channels communicate with the exhaust pipe 9. In this embodiment, there is a clearance between the top ends of the refractory layer 6 and the heat insulation layer 7 and the furnace cover 10 at the top of the outer shell 8, forming a buffer space; The inner lining 5 is hollow inside. Both ends of the inner lining 5 are open ends. The bottom end of the inner lining 5 abuts against the crucible 4, and the top end of the inner lining 5 communicates with the exhaust duct 9. In this embodiment, the bottom end of the exhaust duct 9 is located in the buffer space in the upper part of the outer shell 8 and communicates with the upper space of the outer shell 8. The inner lining 5 is directly opposite to the bottom end of the exhaust duct 9, and there is a gap between the inner lining 5 and the exhaust duct 9. In this way, the impurity gas discharged from the inner lining 5 enters the exhaust duct 9 and is discharged.
[0036] Combined Figure 2 As shown, a ring cavity 16 communicating with the outlet of the plasma torch 1 is provided at the bottom of the outer shell 8. Air holes 17 are provided on the side wall of the ring cavity 16. In this embodiment, a plurality of air holes 17 are provided, and the plurality of air holes 17 are evenly distributed along the circumferential direction of the ring cavity 16. The air holes 17 communicate with the gap channel, and there is a channel communicating with each other between the air holes 17 and the gap channel, which is not shown in the figure. There is a certain gap channel between the crucible 4, the inner lining 5 and the refractory layer 6, and the setting of the air holes 17 aims to maintain pressure balance.
[0037] In this embodiment, both the crucible 4 and the inner lining 5 are made of graphite. The material of the refractory layer 6 is made of refractory bricks stacked or preformed with alumina hollow spheres, and the thermal insulation layer 7 is filled with thermal insulation materials such as glass fiber and thermal insulation cotton.
[0038] As Figure 1 shown, in this embodiment, the outer shell 8 is a double-layer stainless steel water-cooled structure. Specifically: the outer shell 8 includes an inner shell and an outer shell arranged coaxially. There is a water storage space between the inner shell and the outer shell, that is, there is a gap between the inner shell and the outer shell, thus forming a water storage space. The outer shell 8 is provided with a water inlet pipe 11 and a water outlet pipe 12 communicating with the water storage space. The water inlet pipe 11 is located at the lower part of the outer shell 8, and the water outlet pipe 12 is located at the upper part of the outer shell 8. In this way, water is introduced into the water storage space through the water inlet pipe 11 and discharged through the water outlet pipe 12, which is convenient for realizing the circulating cooling of the cooling water and avoiding the overheating of the entire furnace body 3.
[0039] In this embodiment, a pressing plate 18 is provided inside the outer shell 8. The pressing plate 18 is located above the refractory layer 6 and the thermal insulation layer 7, that is, the pressing plate 18 is located in the buffer space inside the outer shell 8. There is a gap between the pressing plate 18 and the thermal insulation layer 7 and the refractory layer 6. A through hole is provided in the middle of the pressing plate 18. The upper part of the inner lining 5 is provided with a stepped engaging portion (that is, the longitudinal section of the upper part of the inner lining 5 is in a T-shaped structure, so that a stepped shape is formed at the upper part of the inner lining 5, which is convenient for buckling on the pressing plate 18 and cooperating with the pressing plate 18 to prevent the inner lining 5 from falling). The inner lining 5 passes through the through hole of the pressing plate 18, and the stepped engaging portion at the upper part of the inner lining 5 abuts against the top of the pressing plate 18, thereby realizing the supporting effect of the pressing plate 18 on the inner lining 5.
[0040] In this embodiment, the pressing plate 18 is detachably connected to the inner layer housing of the outer housing 8. For example, vertical grooves are formed on the side wall of the inner layer housing, and the top ends of the vertical grooves penetrate through the top end of the inner layer housing. A slider is fixedly connected to the outer side of the pressing plate 18. The pressing plate 18 can be installed by inserting the slider into the vertical grooves and abutting against the bottom of the vertical grooves.
[0041] In this embodiment, an annular hole is formed on the pressing plate 18. The annular hole is concentrically arranged with the through hole at the center of the pressing plate 18. The arrangement of the annular hole can accelerate the discharge of the gas in the clearance channel.
[0042] In this embodiment, the outer housing 8 includes a fixed outer housing 81 and a detachable outer housing 82. The bottom end of the fixed outer housing 81 is detachably and coaxially connected to the top end of the detachable outer housing 82. In this embodiment, a fixed outer housing flange 15 is fixedly connected to the bottom end of the fixed outer housing 81, and a detachable outer housing flange 14 is connected to the top end of the detachable outer housing 82. The fixed outer housing 81 and the detachable outer housing 82 are detachably and fixedly connected through the fixed outer housing flange 15 and the detachable outer housing flange 14 and by cooperating with bolts. A sealing ring is provided between the fixed outer housing flange 15 and the detachable outer housing flange 14 to ensure the sealing performance.
[0043] The fixed outer housing 81 is connected to the furnace body fixing seat 2 through a flange and bolts. The detachable outer housing 82 is suspended. The crucible 4 is located inside the detachable outer housing 82. In this embodiment, the detachable outer housing 82 is located at the lower part of the entire outer housing 8, and the area occupied by the detachable outer housing 82 is relatively small, which is convenient for disassembly and installation.
[0044] In this embodiment, a support plate 13 is connected to the bottom of the fixed outer housing 81 and located inside it. A through hole is formed in the middle of the support plate 13. The bottom of the inner lining 5 can pass through the through hole of the support plate 13 and abut against the crucible 4. A communication hole for communicating the clearance channels above and below the support plate 13 is formed on the support plate 13. This communication hole facilitates the gas between the crucible 4 and the refractory layer 6 to enter the clearance channel between the inner lining 5 and the refractory layer 6.
[0045] In this embodiment, the support plate 13 can support the heat insulation layer 7 and the refractory layer 6 located inside the fixed outer housing 81, ensuring that after the detachable outer housing 82 is disassembled, the heat insulation layer 7 and the refractory layer 6 inside the fixed outer housing 81 can maintain a stable state and will not fall off.
[0046] In this embodiment, a stepped engaging portion is provided at the lower part of the inner lining 5. The stepped engaging portion at the lower part of the inner lining 5 abuts against the top of the support plate 13. The structure and effect of the stepped engaging portion at the lower part of the inner lining 5 are the same as those of the stepped engaging portion at the upper part of the inner lining 5, and will not be elaborated here.
[0047] The specific implementation process is as follows: 1) Place the material to be purified in the graphite crucible 4; 2) A DC power supply is connected to the two electrodes of the plasma torch 1, and the DC power supply breaks down the working gas introduced into the plasma torch 1 to form a high-temperature arc. 3) The temperature of the arc is controlled by adjusting the power of the DC power supply and the flow rate of the working gas, so that the heating temperature in the graphite crucible 4 to be processed is ≥ 2800 °C. 4) The impurity components of the material to be purified in the graphite crucible 4 are rapidly evaporated under the action of the high temperature of the plasma to form impurity vapor, and the impurity vapor is then discharged through the exhaust pipe 9, thereby achieving the purpose of material purification. 5) After a long time of heating and purification, the continuous heating of the graphite crucible 4 by the plasma torch 1 is stopped. After the system cools down, the detachable outer shell 82 is separated from the fixed outer shell 81, and the detachable outer shell 82 is removed. Then, the product in the graphite crucible 4 is taken out, and the high-purity material is collected and packaged.
[0048] Example 2 As Figure 3 shown, the difference between this embodiment and Embodiment 1 is that in this embodiment, the fixed outer shell 81 includes an upper outer shell 811 and a lower outer shell 812, and the bottom end of the upper outer shell 811 and the top end of the lower outer shell 812 are coaxially detachably connected by a flange and bolts. In this embodiment, the position where the upper outer shell 811 and the lower outer shell 812 are connected to each other is located in the middle of the fixed outer shell 81, so that after the upper outer shell 811 is disassembled, the refractory layer 6 and the heat-insulating layer 7 inside the outer shell 8 can be installed in sections, which is more convenient for installation and more convenient for later maintenance.
[0049] It should be noted that the above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.
[0050] In the description of the present invention, it should be noted that the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.
[0051] In the description of this document, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings, and is only used to illustrate the relative positional relationship between each component or part, and does not particularly limit the specific installation orientation of each component or part.
[0052] In the description of this document, some terms may be used to represent other meanings in addition to those that can be used to represent orientation or positional relationships. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.
[0053] In the description of this document, the terms "install", "set up", "be provided with", "connect", and "be connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, components, or parts. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0054] In the drawings of this application, the structures, proportions, sizes, etc. are only used to cooperate with the content disclosed in this technical disclosure document for those of ordinary skill in the art to understand and read, and are not used to limit the conditions for the implementation of this application. Therefore, they do not have a technical essence. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that this application can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in this application.
[0055] The terms used in this document are those general terms that are currently widely used in the art considering the functions of this disclosure. However, these terms can change according to the intentions of those of ordinary skill in the art, precedents, or new technologies in the art. In addition, specific terms can be selected by the applicant, and in this case, their detailed meanings will be described in the detailed description of this disclosure. Therefore, the terms used in the document should not be understood as simple names, but based on the meanings of the terms and the overall description of this disclosure.
[0056] Flowcharts or text are used in this document to illustrate the operation steps performed according to the embodiments of this application. It should be understood that the operation steps in the embodiments of this application do not necessarily need to be precisely executed in the recorded order. On the contrary, according to needs, they can be executed in reverse order or processed simultaneously. At the same time, other operations can also be added to these processes, or one or several steps of operations can be removed from these processes.
[0057] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A plasma high-temperature furnace for material purification, comprising a plasma torch, a furnace body, a furnace body fixing seat and a crucible, wherein the furnace body is connected to the furnace body fixing seat, and is characterized in that, The furnace body includes a housing, a lining, a refractory layer, and a heat-insulating layer. The lining, the refractory layer, and the heat-insulating layer are sequentially located inside the housing from the inside to the outside. An exhaust pipe is connected to the top of the furnace body; The crucible is located at the lower part of the housing, and the crucible is located in the inner cavity at the lower part of the refractory layer. The plasma torch is connected to the bottom of the housing; The inside of the lining is hollow, and the bottom end of the lining abuts against the crucible. The top end of the lining communicates with the exhaust pipe. There is a gap channel between both the lining and the crucible and the refractory layer, and the gap channel communicates with the exhaust pipe; A ring cavity communicating with the outlet of the plasma is formed at the bottom of the housing. Air holes are formed on the side wall of the ring cavity, and the air holes communicate with the gap channel; 2. The plasma high-temperature furnace for material purification according to claim 1, characterized in that The housing includes an inner layer housing and an outer layer housing arranged coaxially. There is a water storage space between the inner layer housing and the outer layer housing. A water inlet pipe and a water outlet pipe communicating with the water storage space are provided on the housing. The water inlet pipe is located at the lower part of the housing, and the water outlet pipe is located at the upper part of the housing; 3. The plasma high-temperature furnace for material purification according to claim 1, characterized in that A pressing plate is provided inside the housing. The pressing plate is located above the refractory layer and the heat-insulating layer. A through hole is formed in the middle of the pressing plate. A stepped engaging portion is provided at the upper part of the lining. The lining penetrates through the through hole of the pressing plate, and the stepped engaging portion at the upper part of the lining abuts against the top of the pressing plate; 4. The plasma high-temperature furnace for material purification according to claim 3, characterized in that, An annular hole is formed in the pressing plate; 5. A plasma high-temperature furnace for material purification according to claim 1, characterized in that, The housing includes a fixed housing and a detachable housing. The bottom end of the fixed housing is detachably connected to the top end of the detachable housing coaxially. The fixed housing is connected to the furnace body fixing seat. The detachable housing is suspended. The crucible is located inside the detachable housing; 6. The plasma high-temperature furnace for material purification according to claim 5, characterized in that, A support plate is connected to the bottom of the fixed housing and located inside it. A through hole is formed in the middle of the support plate. The bottom end of the lining can pass through the through hole of the support plate and abut against the crucible. A communication hole for communicating the gap channels above and below the support plate is formed in the support plate; 7. The plasma high-temperature furnace for material purification according to claim 6, characterized in that, A stepped engaging portion is provided at the lower part of the lining. The stepped engaging portion at the lower part of the lining abuts against the top of the support plate; 8. A plasma high-temperature furnace for material purification according to claim 5, characterized in that, The fixed housing includes an upper housing and a lower housing. The bottom end of the upper housing and the top end of the lower housing are detachably connected coaxially; 9. A plasma high-temperature furnace for material purification according to claim 1, characterized in that, Both the crucible and the lining are made of graphite; 10. A plasma high-temperature furnace for material purification according to claim 1, characterized in that, The material of the refractory layer is made by piling refractory bricks or prefabricating and forming alumina hollow spheres.