Internal heat insulation structure of reduction furnace reactor

Abstract

The utility model relates to the technical field of high-purity crystalline silicon production equipment, and provides an internal heat insulation structure of a reduction furnace reactor, which comprises a heat insulation layer connected to the inner wall surface of a bell jar of the reduction furnace reactor; the heat reflecting layer is connected to the heat insulating layer and located on the inner side of the heat insulating layer; wherein the heat insulation layer is mainly composed of a plurality of heat insulation bricks which are laid along the inner wall face of the bell jar and are internally vacuum, and the heat reflection layer is directly or indirectly connected with the innermost side surface of each heat insulation brick. The heat reflecting layer can reflect a part of heat radiation back into the reduction furnace, and the heat insulating layer can reduce heat conduction from the heat reflecting layer to the outer wall surface of the bell jar and reduce the direct contact area between the inner wall surface of the bell jar and a gas-phase medium in the furnace. And meanwhile, the heat reflecting layer and the heat insulating layer can retard flowing of a gas-phase medium in the furnace to reduce convective heat transfer efficiency, so that heat flux passing through the inner wall surface of the bell jar is reduced, and the energy economy of the reduction furnace is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of high-purity crystalline silicon production equipment, in particular to an internal insulation structure of a reduction furnace reactor. Background Art

[0002] The Siemens process for producing silicon materials is the most popular method for producing high-purity crystalline silicon so far. The core of the technology is to convert industrial silicon into trichlorosilane by cold / hot hydrogenation with hydrogen and silicon tetrachloride or synthesis with hydrogen chloride. Since trichlorosilane has a much higher level efficiency than other silane halides in the distillation process, trichlorosilane is selected as the medium for the purification process, and the purified trichlorosilane is reduced to purer elemental silicon by a reduction furnace reactor at high temperature with hydrogen. The main reaction is shown in the following formula ①:

[0003]

[0004] The reduction furnace reactor is mainly composed of two parts: a chassis and a bell jar. The chassis is equipped with electrodes for inserting silicon cores and holes for introducing gaseous reaction media. The inside of the bell jar is provided with a jacket for introducing circulating cooling water. The inner wall of the bell jar is made of nickel-based alloy or stainless steel.

[0005] It can be seen from formula ① that the reduction reaction of trichlorosilane is an endothermic reaction. In order to maintain the temperature conditions necessary for the reaction (about 1100°C), energy needs to be input into the system from the outside. The heat input in the bell jar mainly comes from the enthalpy carried by the reduction electrical system and the incoming gas-phase reaction medium. The reduction electrical system applies current to the silicon core. Since the silicon core has a certain resistance, it can be seen from Joule's law that a part of the electrical energy passing through the silicon core will be converted into thermal energy. The thermal energy heats the silicon core to about 1150°C to maintain a red-hot state. At this time, the silicon core radiates a large amount of heat to the surrounding environment, and the gas-phase reaction medium is at a relatively high temperature.

[0006] When nickel-based alloys or stainless steel are used as pressure vessel materials, they have a large allowable stress within 600°C and are more economical to manufacture. Therefore, in order to prevent the bell jar, which is made of this material and constitutes the pressure boundary of the reduction reaction, from overheating and losing its strength, it is necessary to limit the internal wall temperature to 500-600°C. At this time, circulating pressurized cooling water must be introduced into the jacket and the water temperature must be ensured to be at a level of 150-180°C. Since there is a temperature difference of 320K-450K on both sides of the inner wall of the bell jar, there must be heat flow conducted from the gas side to the water side through the inner wall of the bell jar.

[0007] In general, the heat balance process in the reduction furnace reactor roughly includes the following parts:

[0008] 1) Enthalpy and chemical energy from gas phase material input;

[0009] 2) The heat enthalpy converted from the electrical energy input from the reduction power system;

[0010] 3) The heat enthalpy consumed by the reduction reaction of trichlorosilane is solidified in the chemical energy of the product high-purity crystalline silicon;

[0011] 4) The heat energy that passes through the inner wall of the bell jar enters the circulating cooling water and turns into heat enthalpy;

[0012] 5) The enthalpy and chemical energy carried away by the exhaust gas.

[0013] After observing the above heat balance process, it can be known that 4) the heat energy that passes through the inner wall of the bell jar to the circulating cooling water is neither used to supplement the heat energy consumed by the reduction reaction nor to maintain the temperature conditions required for the reduction reaction. At present, this part of heat can only be recovered through the comprehensive utilization of water vapor. In this process, high exergy value electrical energy is converted into low exergy value low-grade steam, which wastes a lot of energy.

[0014] The amount of this part of heat depends on the temperature to which the inner wall of the bell jar needs to be cooled. Its heat conduction equation is shown in the following equation ②:

[0015]

[0016] Where, Φ is heat flux, in W;

[0017] λ——The thermal conductivity of the material used for the inner wall of the bell jar, in W / (K·m 2 );

[0018] A——heat transfer area, unit: m 2 ;

[0019] T1——the inner wall temperature of the bell jar, in K;

[0020] T2——cooling water temperature, in K;

[0021] d – the thickness of the inner wall of the bell jar, in m.

[0022] Analyze formula ②, where λ is the intrinsic property of the material itself, and its value is constant. Once the bell jar is manufactured, the size of its heat transfer area A remains unchanged. T1 actually depends on the high-temperature mechanical properties of the material and is a parameter that needs to be controlled as a dependent variable. d is determined by the high-temperature mechanical properties of the material, the pressure difference on both sides of the inner wall, and the geometric shape of the bell jar, and is considered as a constant value. At this time, in order to ensure that T1 is constant, T2 and Φ must both be constant values.

[0023] When d is a constant value, increasing T2 to reduce Φ will inevitably lead to an increase in T1, which will not meet the requirements. Assuming d is an independent variable, increasing T2, to ensure that T1 does not increase, it is necessary to reduce d to reduce thermal resistance, but the structural strength will be reduced at this time, which will also not meet the requirements. Considering that d is very large (that is, the inner wall of the bell jar is very thick), in theory, due to the temperature gradient inside the material, a low-temperature zone will be formed on the low-temperature side. This part of the structure has a high strength and can bear pressure, but the actual situation is that due to the large thermal conductivity of nickel-based alloys or stainless steel, the structural wall thickness required to establish such a pressure-bearing low-temperature zone is very exaggerated.

[0024] From the above paradox, it can be seen that without introducing new variables, there is little prospect for re-optimizing energy economy by changing T2 or d, and it will lead to a decrease in overall economy.

[0025] Therefore, how to reduce this part of energy consumption and achieve energy saving without reducing the overall reduction reaction efficiency is an urgent problem to be solved in the current process of optimizing the energy economy of the reduction furnace reactor. Utility Model Content

[0026] In view of the deficiencies of the prior art, the utility model provides an internal insulation structure of a reduction furnace reactor to solve the problem of low energy economy of the reduction furnace reactor.

[0027] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0028] An internal insulation structure of a reduction furnace reactor, comprising:

[0029] A heat insulating layer connected to the inner wall surface of the bell jar of the reduction furnace reactor; and

[0030] A heat reflection layer connected to the heat insulation layer and located inside the heat insulation layer;

[0031] The heat-insulating layer is mainly composed of a number of heat-insulating bricks which are laid along the inner wall of the bell jar and have a vacuum inside, and the heat-reflecting layer is directly or indirectly connected to the innermost surface of each of the heat-insulating bricks.

[0032] In one embodiment disclosed in the present application, the insulating brick is in the shape of a rectangular parallelepiped, and is connected to the inner wall surface of the bell jar via a supporting assembly.

[0033] In one embodiment disclosed in the present application, the support assembly includes a support nail with threads at both ends and four support plates welded to the support nail;

[0034] One end of the support nail is threadedly connected to a first support welded to the inner wall of the bell jar and having a threaded hole;

[0035] The four support plates are evenly distributed around the axis of the support nail, and are used to support a corner of the insulation brick and space adjacent insulation bricks;

[0036] The other end of the support nail is connected with a first fastener to press the insulation brick against the inner wall surface of the bell jar.

[0037] In one embodiment disclosed in the present application, a slot is provided on the side surface of one end of the supporting nail connected to the first fastener.

[0038] In one embodiment disclosed in the present application, the insulating brick is a rectangular hollow box-shaped structure, six faces of which are made of dense and airtight plates, and the interior is evacuated;

[0039] Alternatively, the insulating brick has a rectangular foam structure, and a plurality of cavities which are not connected to the outer surface are arranged inside the insulating brick, and the interior of the cavities is evacuated.

[0040] In one embodiment disclosed in the present application, the insulating bricks are made of ceramic material.

[0041] In one embodiment disclosed in the present application, the heat reflective layer is a precious metal coating on the innermost surface of each insulating brick.

[0042] In one embodiment disclosed in the present application, the heat reflection layer is mainly composed of a heat reflection plate covering each insulating brick.

[0043] In one embodiment disclosed in the present application, a through hole is opened in the middle of the heat reflection plate;

[0044] A second support with a screw is provided in the middle of the innermost surface of each of the insulating bricks;

[0045] The screw rod of the second support is sleeved onto the cushion block and passed through the through hole, and then connected with a second fastener to compress the heat reflecting plate.

[0046] In one embodiment disclosed in the present application, the heat reflection plate is made of metal or ceramic material, and its inner surface is plated with precious metal.

[0047] Compared with the prior art, the beneficial effects of the utility model are:

[0048] 1. The heat reflection layer can reflect part of the heat radiation back to the interior of the reduction furnace. The insulation layer can reduce the heat conduction from the heat reflection layer to the outer wall of the bell jar and reduce the direct contact area between the inner wall of the bell jar and the gas phase medium in the furnace. At the same time, the heat reflection layer and the insulation layer can block the flow of the gas phase medium in the furnace to reduce the convective heat transfer efficiency, thereby reducing the heat flux through the inner wall of the bell jar and improving the energy economy of the reduction furnace.

[0049] 2. The insulating bricks made of ceramic materials have high thermal resistance characteristics and will not volatilize substances that pollute the reaction medium at high temperatures. They can effectively meet the clean environment conditions required for the production of high-purity silicon.

[0050] 3. Through the cooperation of the support assembly and the first support, the insulating bricks can be fixed to the inner wall of the bell jar, separating the inner wall of the bell jar to reduce its direct heat transfer area with the gas phase medium in the furnace, thereby reducing the heat transferred to the inner wall of the bell jar by heat conduction and convection.

[0051] 4. Through the cooperation of the second support, the pad and the second fastener, the heat reflecting plate can be supported and fixed, so that it can be covered on the inner side of the insulating brick in the form of a tile to achieve heat reflection; at the same time, the pad can separate the heat reflecting plate from the supporting assembly to prevent the heat reflecting plate from contacting the end of the support nail connected to the first fastener to form a thermal bridge, thereby preventing contact heat transfer.

[0052] 5. The precious metal coating has high thermal reflectivity and can effectively reduce the radiation heat transfer to the inner wall of the bell jar through heat reflection. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0054] Figure 1 This is a schematic diagram of the structure of the utility model applied in the bell jar of a reduction furnace reactor;

[0055] Figure 2 for Figure 1 A schematic diagram of the enlarged structure of the middle part A;

[0056] Figure 3 for Figure 1 The enlarged structural diagram of the middle part B;

[0057] Figure 4 It is a schematic diagram of the three-dimensional structure of the insulation brick;

[0058] Figure 5 Schematic diagram of the three-dimensional structure of the heat reflection plate;

[0059] Figure 6 is a schematic diagram of the three-dimensional structure of the support assembly;

[0060] Figure 7 It is a schematic diagram of S1 during the installation process of the utility model;

[0061] Figure 8It is a schematic diagram of S2 during the installation process of the utility model;

[0062] Fig. 9 It is a schematic diagram of S3 during the installation process of the utility model;

[0063] Fig.10 It is a schematic diagram of S4 during the installation process of the utility model. DETAILED DESCRIPTION

[0064] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0065] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0066] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0067] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0069] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present invention.

[0070] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0071] See also Figures 1 to 10 As shown, the utility model provides an internal insulation structure of a reduction furnace reactor, comprising:

[0072] The heat-insulating layer is connected to the inner wall surface of the bell jar 1 of the reduction furnace reactor; and

[0073] A heat reflecting layer is connected to the heat insulating layer and is located on the inner side of the heat insulating layer (i.e., the two are arranged inside and outside, and the heat reflecting layer is closer to the geometric center of the bell jar 1 than the heat insulating layer);

[0074] The heat-insulating layer is mainly composed of a number of heat-insulating bricks 10 which are laid along the inner wall of the bell jar and have a vacuum inside, and the heat-reflecting layer is directly or indirectly connected to the innermost surface of each heat-insulating brick 10 .

[0075] Specifically, the insulation layer is located on the inner side of the inner wall of the bell of the reduction furnace reactor, and the insulation bricks 10 contained therein have a certain degree of vacuum inside. The heat reflection layer does not contact the inner wall of the bell, nor does it form a heat bridge with the inner wall of the bell through other metal materials. The heat conduction from the inner side of the reduction furnace reactor to the outer side of the bell mainly relies on radiation heat transfer and convection heat transfer. The heat reflection layer in this internal insulation structure can reflect a part of the heat radiation back to the inside of the reduction furnace, and the insulation layer can reduce the heat conduction of the heat reflection layer to the outer wall of the bell and reduce the direct contact area between the inner wall of the bell and the gas phase medium in the furnace. At the same time, the heat reflection layer and the insulation layer can block the flow of the gas phase medium in the furnace to reduce the convection heat transfer efficiency, thereby reducing the heat flux through the inner wall of the bell, and improving the energy economy of the reduction furnace. The internal insulation structure layer has high thermal resistance and is not pressure-bearing. It only bears the internal pressure in the furnace and the chemical erosion of the gas phase reaction medium. After the introduction of new variables, the aforementioned energy economy optimization problem will have a prospect under the condition of overall economic feasibility.

[0076] See also Figure 2 , Figure 4 and Figure 6 As shown, the insulating brick 10 is in the shape of a rectangular parallelepiped, and is connected to the inner wall of the bell jar through a support assembly 20. Specifically, the support assembly 20 includes a support nail 21 with threads at both ends and four support plates 22 welded to the support nail 21. One end of the support nail 21 is threadedly connected to a first support 2 welded to the inner wall of the bell jar and having a threaded hole. The four support plates 22 are evenly distributed around the axis of the support nail 21 and are used to support a corner of the insulating brick 10 and space adjacent insulating bricks 10. The other end of the support nail 21 is connected to a first fastener 23 (such as a gasket and nut used in combination) to press the insulating brick 10 against the inner wall of the bell jar. Through the cooperation of the support assembly 20 and the first support 2, the insulating brick 10 can be fixed to the inner wall of the bell jar, and the inner wall of the bell jar can be separated to reduce its direct heat transfer area with the gas phase medium in the furnace, thereby reducing the heat transferred to the inner wall of the bell jar by heat conduction and convection.

[0077] In order to facilitate the disassembly of the support assembly 20 , a slot is provided on the side surface of one end of the support nail 21 connected to the first fastener 23 .

[0078] The insulating brick 10 is a rectangular hollow box-shaped structure, and its six faces are made of dense and airtight plates, and the interior is evacuated. Specifically, under vacuum conditions, the six plates constituting each face of the rectangular parallelepiped are welded into a box-shaped structure using induction heating, hydrogen-oxygen flame, and high-frequency plasma flame to obtain the insulating brick 10. The vacuumed rectangular hollow box-shaped insulating brick 10 has its heat conduction process limited to the thickness of the rectangular parallelepiped, and only heat radiation exists in the hollow interior.

[0079] Alternatively, the insulating brick 10 is a rectangular foam structure, and a plurality of cavities are provided inside the structure that are not connected to the outer surface, and the inside of the cavities is evacuated. Specifically, a high-purity gas (such as hydrogen, nitrogen, argon or other inert gases) is injected into the insulating material in the molten state through a breathable brick arranged at the bottom of the molten pool, and the bubbles are dispersed in the molten pool by stirring the molten pool, and then the molten pool is placed in a mold, and the mold is evacuated and cooling water is injected into the mold at the same time, so that the small bubbles in the molten pool expand and form a foam structure, and the insulating brick 10 of this structure is prepared after cooling and molding. Injecting gas into the molten pool is not the only way to foam. In fact, similar effects can be obtained by using substances that can decompose and produce gas at high temperatures.

[0080] Since the insulating bricks 10 are in contact with the atmosphere and high temperature in the reduction furnace at the same time, the materials commonly used in engineering to manufacture high thermal resistance under high temperature conditions, such as silicon bricks, high-alumina bricks, clay refractory bricks, carbon bricks and other furnace building materials and insulating materials such as aluminum silicate, calcium silicate, and magnesium silicate, may volatilize substances that pollute the reaction medium at high temperatures, and cannot ensure the internal clean environment of the reduction furnace, which will cause the purity of the high-purity crystalline silicon product to be reduced and unqualified, that is, the above materials cannot meet the clean environment conditions required for the production of high-purity crystalline silicon. Therefore, it is not feasible to simply use the above materials to establish a high thermal resistance insulation structure on the inner wall of the bell jar, and the materials used to make the insulating bricks 10 must be carefully considered. In order to meet the above requirements, the material must have the following characteristics:

[0081] 1) Melting point>1100℃;

[0082] 2) It has very low vapor pressure within 1100℃;

[0083] 3) It basically does not react with hydrogen, hydrogen chloride, chlorosilane and other substances within 1100°C, or has only a very low reaction rate;

[0084] 4) Contains no phosphorus, boron or carbon;

[0085] 5) It is easy to obtain high-purity bulk materials;

[0086] 6) Relatively low high temperature thermal conductivity;

[0087] 7) Low coefficient of thermal expansion.

[0088] Materials meeting the above characteristics are usually special ceramic materials, such as alumina ceramics, artificial sapphire, zirconium oxide ceramics, aluminum nitride, etc. High-purity crystalline silicon itself is also a suitable material.

[0089] The materials listed above are just examples, and in fact any material that meets the above technical requirements can be used as the material of the insulating brick 10. Therefore, in this embodiment, the insulating brick 10 is preferably made of ceramic material.

[0090] The heat reflection layer is a precious metal coating on the innermost surface of each insulating brick 10. That is to say, the heat reflection layer does not exist as an independent structural layer, but is actually a characteristic of the innermost surface of the insulating brick 10, such as a bright coating formed by plating precious metals such as gold or silver on the innermost surface of the insulating brick 10, which can also achieve the function of infrared reflection.

[0091] Alternatively, the heat reflection layer exists as an independent structural layer, which is mainly composed of a heat reflection plate 30 (see Figure 5 ). Specifically, a through hole 31 is provided in the middle of the heat reflecting plate 30, and a second support 11 with a screw is provided in the middle of the innermost surface of each insulating brick 10. The screw of the second support 11 is sleeved with a pad 12, passes through the through hole 31, and is connected with a second fastener 13 (such as a gasket and nut used in combination) to press the heat reflecting plate 30. Through the cooperation of the second support 11, the pad 12 and the second fastener 13, the heat reflecting plate 30 can be supported and fixed, so that it can be covered on the inner side of the insulating brick 10 in the form of a tile to achieve infrared reflection; at the same time, the pad 12 can separate the heat reflecting plate 30 from the support assembly 20, so as to prevent the heat reflecting plate 30 from contacting with one end of the support nail 21 connected with the first fastener 23 to form a thermal bridge, thereby preventing contact heat transfer.

[0092] In this embodiment, the heat reflection plate 30 is made of a metal with a high melting point (such as a nickel-based alloy) or a special ceramic material, and its inner surface is plated with a precious metal (such as gold or silver). The precious metal coating has a high thermal reflectivity and can effectively reduce the radiation heat transfer to the inner wall of the bell jar through heat reflection.

[0093] For the independent heat reflection plate 30, the specific installation steps of the internal insulation structure are as follows:

[0094] 1. Connect the support assembly 20 to the first support 2 on the inner wall of the bell jar, and make the support plates 22 of four adjacent support assemblies 20 form a rectangular grid (see Figure 7 and Figure 8 shown);

[0095] 2. Place multiple insulating bricks 10 into each rectangular grid one by one, and then screw the first fastener 23 into the support nail 21 to press the insulating bricks 10 against the inner wall of the bell jar (see Fig. 9 shown);

[0096] 3. Insert the spacer 12 onto the screw of the second support 11, then align the through hole 31 of the heat reflecting plate 30 with the screw and pass it through, and then screw the second fastener 13 into the screw to press the heat reflecting plate 30 (see Fig.10 as shown).

[0097] The above embodiments are only preferred embodiments of the present utility model and are not limitations on the technical solutions of the present utility model. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present utility model.

Claims

1. An internal insulation structure of a reduction furnace reactor, characterized in that: include: A heat-insulating layer connected to the inner wall surface of the bell jar of the reduction furnace reactor; and A heat reflection layer connected to the heat insulation layer and located inside the heat insulation layer; The heat-insulating layer is mainly composed of a number of heat-insulating bricks which are laid along the inner wall of the bell jar and have a vacuum inside, and the heat-reflecting layer is directly or indirectly connected to the innermost surface of each of the heat-insulating bricks.

2. The internal insulation structure of the reduction furnace reactor according to claim 1, characterized in that: The heat-insulating brick is in a rectangular shape and is connected to the inner wall surface of the bell jar through a supporting component.

3. The internal insulation structure of the reduction furnace reactor according to claim 2, characterized in that: The support assembly includes a support nail with threads at both ends and four support plates welded to the support nail; One end of the support nail is threadedly connected to a first support welded to the inner wall of the bell jar and having a threaded hole; The four support plates are evenly distributed around the axis of the support nail, and are used to support a corner of the insulation brick and space adjacent insulation bricks; The other end of the support nail is connected with a first fastener to press the insulation brick against the inner wall surface of the bell jar.

4. The internal insulation structure of the reduction furnace reactor according to claim 3, characterized in that: A slot is formed on the side surface of one end of the supporting nail connected to the first fastener.

5. The internal insulation structure of the reduction furnace reactor according to any one of claims 2 to 4, characterized in that: The insulating brick is a rectangular hollow box-shaped structure, the six sides of which are made of dense and airtight plates, and the interior is evacuated; Alternatively, the insulating brick has a rectangular foam structure, and a plurality of cavities which are not connected to the outer surface are arranged inside the insulating brick, and the interior of the cavities is evacuated.

6. The internal insulation structure of the reduction furnace reactor according to claim 5, characterized in that: The heat-insulating bricks are made of ceramic material.

7. The internal insulation structure of the reduction furnace reactor according to claim 1 or 6, characterized in that: The heat reflection layer is a precious metal coating on the innermost surface of each insulating brick.

8. The internal insulation structure of the reduction furnace reactor according to claim 1 or 6, characterized in that: The heat reflection layer is mainly composed of a heat reflection plate covering each heat insulating brick.

9. The internal insulation structure of the reduction furnace reactor according to claim 8, characterized in that: A through hole is provided in the middle of the heat reflecting plate; A second support with a screw is provided in the middle of the innermost surface of each of the insulating bricks; The screw rod of the second support is sleeved onto the cushion block and passed through the through hole, and then connected with a second fastener to compress the heat reflecting plate.

10. The internal insulation structure of the reduction furnace reactor according to claim 9, characterized in that: The heat reflection plate is made of metal or ceramic material, and its inner surface is plated with precious metal.

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