High-temperature purification furnace

Abstract

The utility model relates to a high-temperature purification furnace which comprises a furnace body and a fixed table fixed with the furnace body, a heating and heat preservation assembly is arranged in the furnace body, and the heating and heat preservation assembly is connected with the furnace body in a lifting mode through a heating lifting assembly. The heating and heat preservation assembly comprises a heat insulation cage, a plurality of graphite heaters and a heat preservation layer, the graphite heaters and the heat preservation layer are arranged in the heat insulation cage, the graphite heaters are arranged along the circumference, and the heat preservation layer is arranged between the graphite heaters and the inner wall of the heat insulation cage. The heating and heat preservation assembly adopts an isostatic pressing graphite plate type heater, can bear large-current electricity conduction, is good in temperature uniformity, and can be stably used for a long time under the ultra-high temperature condition; the heat preservation layer is made of viscose-based graphite soft felt, and the viscose-based graphite soft felt has the unique air laying technology, has a fiber network structure with high uniformity and ideal chemical performance and good felt body tensile strength, and meanwhile is low in heat conductivity and beneficial to heat preservation. The device has the characteristics of simple structure, convenience in operation and capability of greatly reducing the pollution to the environment.

Description

Technical Field

[0001] The utility model belongs to the field of carbon material processing, in particular to a high-temperature purification furnace. Background Art

[0002] The purity of graphite products, carbon felt or SiC powder determines the use characteristics and comprehensive performance of materials such as graphite products, carbon felt or SiC powder. The higher the purity of graphite products, carbon felt or SiC powder, the higher the application value. High-purity graphite products, carbon felt or SiC powder refer to graphite with a fixed carbon content of more than 99.9%. The production of high-purity graphite products, carbon felt or SiC powder mainly removes impurities in graphite products, carbon felt or SiC powder through purification processes. The main impurity components contained in graphite products, carbon felt or SiC powder are oxides and silicate minerals of potassium, sodium, magnesium, iron, calcium, aluminum, etc. At present, the methods for producing high-purity graphite products, carbon felt or SiC powder at home and abroad usually include chemical methods (hydrofluoric acid method and chlorination roasting method) and physical methods (high temperature method). The hydrofluoric acid method uses the impurities in graphite products, carbon felt or SiC powder to react with hydrofluoric acid to generate fluorides and volatiles soluble in water to achieve the purpose of purification. This method is highly corrosive to equipment and highly toxic. The chlorination roasting method uses chlorine to convert impurities in graphite products, carbon felt or SiC powder into volatiles. Chlorine is highly corrosive and toxic, with high procurement and transportation costs, and pollutes the environment. The process system is unstable and the production cost is high, which limits the promotion and application of this process to a certain extent. Therefore, a high-temperature purification furnace that can reduce pollution to the environment and has a simple structure and convenient operation is urgently needed. This is a problem we need to solve. Utility Model Content

[0003] In view of the various deficiencies in the prior art, a high-temperature purification furnace is proposed, which processes graphite products, carbon felt or SiC powder through high-temperature calcination and directional flow of process gas, and discharges impurity elements from the matrix through physical diffusion and chemical reaction, so as to form a low ash content and a metal content reduced to the PPB order of magnitude, thereby meeting the requirements of semiconductor crystal growth for graphite quality (or powder raw material).

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] A high-temperature purification furnace comprises a furnace body and a fixing table fixed to the furnace body, a heating and heat preservation component is arranged in the furnace body, and the heating and heat preservation component is connected to the furnace body in a lifting manner through a heating lifting component;

[0006] The heating and heat-insulating component comprises a heat-insulating cage, a graphite heater arranged in the heat-insulating cage and a heat-insulating layer. A plurality of graphite heaters are arranged along a circumference, and the heat-insulating layer is arranged between the graphite heater and the inner wall of the heat-insulating cage.

[0007] Furthermore, the furnace body includes an upper furnace chamber and a lower furnace chamber, the upper part of the upper furnace chamber is fixed to the fixed platform, the upper part of the lower furnace chamber is lifted and opened and closed with the upper furnace chamber through the lower furnace chamber lifting assembly, and the lower part is fixed to the ground through the lower furnace chamber lifting assembly.

[0008] Furthermore, the heat insulation cage is a bottomless box structure, and its cross section is circular.

[0009] Further, the insulation cage is made of stainless steel, and the insulation layer is made of viscose-based insulation felt.

[0010] Furthermore, the heating lifting assembly adopts a linear guide rail, and is sealed and connected to the furnace body. The linear guide rail is driven by a servo motor arranged on the top of the upper furnace chamber.

[0011] Furthermore, the fixed platform is fixed to the ground through columns, and a water distributor for cooling water inlet and outlet is arranged on the columns to transport cooling water to the furnace body.

[0012] Furthermore, a vacuum meter, a mass flow meter and an infrared thermometer are installed on the upper furnace chamber.

[0013] The beneficial effects of the utility model are:

[0014] 1. The heating and insulation components use isostatic graphite plate heaters, which can carry large currents and have good temperature uniformity, and can be used stably for a long time under ultra-high temperature conditions; the insulation layer uses viscose-based graphite soft felt. The viscose-based graphite soft felt has a unique air-laid technology, has high uniformity, an ideal fiber network structure with chemical properties and good felt tensile strength, and at the same time, its thermal conductivity is low, which is conducive to thermal insulation.

[0015] 2. The heating and insulation components include an insulation cage, a graphite heater and an insulation layer. The insulation cage is connected to the upper furnace chamber through a linear guide rail. The linear guide rail drives the insulation cage to move up and down in the furnace body to control the growth rate of the silicon ingot, which is easy to operate.

[0016] 3. The lower furnace chamber is opened and closed with the upper furnace chamber by a spiral elevator, which also facilitates loading and unloading in the lower furnace chamber. The structure is simple and the loading and unloading process is convenient to operate.

[0017] 4. The utility model adopts a heating and heat preservation component to place medium-carbon or high-carbon graphite at a higher process temperature for continuous heating through a high-temperature method, so that impurities in graphite products, carbon felt or SiC powder are volatilized above the boiling point to achieve the purpose of purification. This is different from the chemical method (hydrofluoric acid method and chlorination roasting method) in the prior art, and can greatly reduce pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0019] In the figure: 1-furnace body, 101-upper furnace chamber, 102-lower furnace chamber, 2-fixed table, 3-heating and heat preservation component, 301-insulation cage, 302-graphite heater, 303-insulation layer, 4-heating lifting component, 5-lower furnace chamber lifting component. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the drawings of the present invention. Based on the embodiments in this application, other similar embodiments obtained by ordinary technicians in this field without making creative work should all fall within the scope of protection of this application. In addition, the directional words mentioned in the following embodiments, such as "up", "down", "left", "right", etc., are only referenced to the directions of the drawings. Therefore, the directional words used are used to illustrate rather than limit the invention.

[0021] The utility model is further described below in conjunction with the accompanying drawings and preferred embodiments.

[0022] like Figure 1 As shown, a high-temperature purification furnace includes a furnace body 1 and a fixed platform 2. The furnace body 1 includes an upper furnace chamber 101 and a lower furnace chamber 102. The upper part of the upper furnace chamber 101 is fixedly connected to the fixed platform 2, and the fixed platform 2 is fixed to the ground through columns. In this embodiment, three columns are provided. The upper part of the lower furnace chamber 102 is connected to the upper furnace chamber 101 by the lower furnace chamber lifting assembly 5, and the lower furnace chamber 102 and the upper furnace chamber 101 can be opened and closed at the same time, which is also convenient for loading and unloading in the lower furnace chamber 102. The lower part of the lower furnace chamber 102 is fixed to the ground through the lower furnace chamber lifting assembly 5. In this embodiment, the lower furnace chamber lifting assembly 5 adopts a spiral elevator, and three groups of spiral elevators are provided. The lower furnace chamber 102 and the upper furnace chamber 101 are both made of 304 stainless steel, which is suitable for high temperature 2400℃ working conditions.

[0023] The upper furnace chamber 101 is provided with a heating and heat preservation component 3, which is connected to the furnace body 1 by a heating and lifting component 4 so as to be liftable. Specifically, the heating and heat preservation component 3 includes a heat insulation cage 301, a graphite heater 302 and a heat preservation layer 303. The heat insulation cage 301 is a box surrounded by four sides, and its cross section is circular. The graphite heater 302 and the heat preservation layer 303 are fixed inside the heat insulation cage 301, and the heat preservation layer 303 is arranged between the graphite heater 302 and the inner wall of the heat insulation cage 301. In this embodiment, the heat insulation cage 301 is arranged in an inverted barrel shape, and its top is connected to the heating and lifting component 4. The heating and lifting component 4 is used to realize its lifting in the furnace body 1, which is conducive to the growth of crystalline silicon at different stages. The heating and lifting component 4 adopts a linear guide rail, and the linear guide rail is sealed and fixed to the furnace body through a stainless steel bellows. Three groups of linear guide rails are arranged, and the linear guide rails are driven by a servo motor arranged on the top of the upper furnace chamber.

[0024] The graphite heaters 302 are arranged in multiple groups, and the multiple groups of graphite heaters 302 are arranged along the circumference, and are connected to the cables located above the insulation cage 301 through copper electrodes. In this embodiment, 6 groups of graphite heaters 302 are arranged, and the graphite heaters 302 are plate-type isostatically pressed graphite heaters, the insulation cage is made of stainless steel, and the insulation layer is made of viscose-based insulation felt.

[0025] In addition, a water distributor for cooling water in and out is provided on the column, which is used to transport cooling water to the furnace body. A vacuum gauge, a mass flow meter and an infrared thermometer are installed on the upper furnace chamber. In this embodiment, two capacitive vacuum gauges are installed in the upper furnace chamber, which are used to measure the rough reading and precise reading pressure in the furnace body, respectively, the mass flow meter is used in various stages of the purification process, and the infrared thermometer is used to monitor the temperature in the furnace body.

[0026] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made within the scope of this application should still fall within the scope of the present invention.

Claims

1. A high-temperature purification furnace, comprising a furnace body and a fixing table fixed to the furnace body, wherein a heating and heat preservation component is arranged in the furnace body, characterized in that: The heating and heat-insulating assembly is connected to the furnace body in a liftable manner via a heating lifting assembly; The heating and heat-insulating component comprises a heat-insulating cage, a graphite heater arranged in the heat-insulating cage and a heat-insulating layer. A plurality of graphite heaters are arranged along a circumference, and the heat-insulating layer is arranged between the graphite heater and the inner wall of the heat-insulating cage.

2. A high-temperature purification furnace according to claim 1, characterized in that: The furnace body comprises an upper furnace chamber and a lower furnace chamber, wherein the upper portion of the upper furnace chamber is fixed to a fixed platform, the upper portion of the lower furnace chamber is opened and closed by a lower furnace chamber lifting assembly, and the lower portion of the lower furnace chamber is fixed to the ground by a lower furnace chamber lifting assembly.

3. A high temperature purification furnace according to claim 2, characterized in that: The heat insulation cage is a bottomless box structure, and its cross section is circular.

4. A high-temperature purification furnace according to claim 3, characterized in that: The insulation cage is made of stainless steel, and the insulation layer is made of viscose-based insulation felt.

5. A high-temperature purification furnace according to any one of claims 1 to 4, characterized in that: The heating lifting assembly adopts a linear guide rail, which is sealed and connected to the furnace body. The linear guide rail is driven by a servo motor arranged on the top of the upper furnace chamber.

6. A high-temperature purification furnace according to claim 5, characterized in that: The fixed platform is fixed to the ground through columns, and a water distributor for cooling water inlet and outlet is arranged on the columns to transport cooling water to the furnace body.

7. A high temperature purification furnace according to claim 6, characterized in that: A vacuum gauge, a mass flow meter and an infrared thermometer are installed on the upper furnace chamber.

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