Electrolytic aluminum flue gas purification system
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ABA ALUMINUM FACTORY
- Filing Date
- 2023-11-21
- Publication Date
- 2026-06-02
Smart Images
Figure CN117717875B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aluminum electrolysis flue gas purification technology, and in particular to an aluminum electrolysis flue gas purification system. Background Technology
[0002] The electrolytic flue gas generated during the alumina electrolysis process contains CO, CO2 and a large amount of gaseous fluoride (HF). Direct emission of gaseous fluoride from the electrolytic flue gas will cause environmental pollution and have toxic side effects on animals and plants. Summary of the Invention
[0003] In view of the above situation, the present invention provides an electrolytic aluminum flue gas purification system, which uses alumina to purify electrolytic flue gas. Fresh alumina is crushed into fresh alumina powder with smaller particle size and smoother shape, so that the fresh alumina powder is sprayed out and fully contacts HF in the electrolytic flue gas, thereby ensuring the adsorption effect of HF and ensuring that the emission meets the standards.
[0004] To achieve the above objectives, the present invention provides the following technical solution:
[0005] This invention provides an electrolytic aluminum flue gas purification system, comprising:
[0006] A smoke hood is installed through the top cover of the electrolytic cell and close to the fire port; the smoke hood has a smoke exhaust pipe and a feed pipe.
[0007] Storage tanks are used to store fresh alumina; the storage tanks are connected to the feed pipes via a discharge pipe.
[0008] The pulverizing mechanism is located inside the smoke hood;
[0009] First gas-solid separator;
[0010] The crushing mechanism includes:
[0011] A fixing plate is attached to the inner wall of the smoke hood;
[0012] The moving grinding disc has its edge bent downwards and then extends outwards in the horizontal direction to form an annular part; the lower side of the annular part is in rotatable contact with the upper side of the fixed plate; multiple air holes are distributed on the annular part, and the fixed plate is used to seal the air holes, but there are always some air holes on the annular part that are not sealed by the fixed plate.
[0013] The fixed grinding disc is fixed above the moving grinding disc, and the fixed grinding disc and the moving grinding disc are used together; the fixed grinding disc has a material guide channel, one end of which is connected to the feed pipe and the other end extends to the bottom of the fixed grinding disc;
[0014] Drive components are used to rotate the grinding disc.
[0015] In some embodiments of the present invention, a filter cloth is provided between the gas phase outlet and the solid phase outlet of the first gas-solid separator, and an inlet pipe is provided between the filter cloth and the solid phase outlet of the first gas-solid separator. The inlet pipe is connected to the exhaust pipe through a conveying conduit.
[0016] In some embodiments of the present invention, the outlet of the inlet tube is bent upwards and faces the filter cloth.
[0017] In some embodiments of the present invention, a guide rail is provided on the fixing plate, and a groove matching the guide rail is provided on the lower side of the annular portion.
[0018] In some embodiments of the present invention, it further includes:
[0019] The shell-breaking tube is used to create a crater at the crust formation point inside the electrolytic cell and can drive the grinding disc to rotate.
[0020] The feed pipe is fixedly installed, and its outer wall is longitudinally slidably connected to the inner wall of the shell-breaking pipe. The upper end of the feed pipe is connected to the solid phase outlet of the first gas-solid separator.
[0021] In some embodiments of the present invention, the lower part of the shell-breaking tube is hollow prism-shaped, and the middle and upper parts are cylindrical. The upper part of the shell-breaking tube is slidably connected to the smoke collection hood, the middle part slides through the fixed grinding disc, and the lower part slides longitudinally through the moving grinding disc and can drive the moving grinding disc to rotate.
[0022] In some embodiments of the present invention, the lower end of the shell-breaking tube gradually narrows in diameter.
[0023] In some embodiments of the present invention, it further includes:
[0024] The mixing conveyor connects the solid phase outlet and the feed pipe of the first gas-solid separator.
[0025] Branch pipes are used to connect storage tanks and mixing conveyors;
[0026] Nitrogen pipe, used to introduce nitrogen into the mixing conveyor;
[0027] Fluorine-containing alumina powder is driven by nitrogen gas and rubs against fresh alumina to generate static electricity, causing the fluorine-containing alumina powder to be adsorbed onto the fresh alumina.
[0028] In some embodiments of the present invention, a second gas-solid separator, a pressure relief pipe, a buffer tank, and a recovery pipe are also included;
[0029] The inlet of the second gas-solid separator is connected to the outlet of the mixing conveyor, and the gas phase outlet of the second gas-solid separator is connected to the side wall of the buffer tank through a pressure relief pipe.
[0030] One end of the recovery pipe is connected to the side wall of the buffer tank, and the other end is connected to the discharge pipe. The inlet of the recovery pipe and the outlet of the pressure relief pipe are set opposite each other, and a filter plate is set between them. The filter plate is used to filter fresh alumina, and fluorine-containing alumina powder can pass through the filter plate.
[0031] In some embodiments of the present invention, a heat exchanger is also included, through which the electrolytic flue gas and the nitrogen pipe exchange heat.
[0032] The embodiments of the present invention have at least the following advantages or beneficial effects:
[0033] 1. Fresh alumina is crushed into smaller and more rounded alumina powder. The fresh alumina powder falls into the pores of the annular part. When the pores are blocked by the fixing plate, the fresh alumina powder remains in the pores. As the moving grinding disc rotates, the fixing plate is displaced from the pores. The electrolytic flue gas in the electrolytic cell rises and passes through the pores, causing the fresh alumina powder to be sprayed out and fully contact the HF in the electrolytic flue gas, thereby ensuring the adsorption effect of HF.
[0034] Second, the pores sealed by the fixed plate can retain a larger amount of fresh alumina powder, thereby increasing the amount of fresh alumina powder used for HF adsorption (more fresh alumina powder comes into contact with the electrolytic flue gas), thus ensuring the HF adsorption effect.
[0035] Third, during the rotation of the moving grinding disc, only some of the pores are open at any given time, resulting in a relatively small gas flow rate. This helps to reduce or limit the exhaust volume, thereby reducing heat loss in the electrolytic cell.
[0036] Fourth, crushing fresh alumina into smaller and smoother-shaped powder can reduce wear on the conveying conduit (the large particle size and irregular shape of fresh alumina in the storage tank cause great wear on the conveying conduit).
[0037] Fifth, crushing fresh alumina into smaller, more rounded powder can reduce the impact on the internal filtration equipment of the first gas-solid separator.
[0038] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description
[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0040] Figure 1 This is a schematic diagram of the structure of an electrolytic aluminum flue gas purification system;
[0041] Figure 2 This is a schematic diagram of the structure of the smoke hood and the pulverizing mechanism;
[0042] Figure 3 for Figure 2 A magnified view of a portion of position A in the middle.
[0043] icon:
[0044] 1-Fume hood, 11-Fume exhaust pipe, 12-Feed pipe,
[0045] 2-Storage tank, 21-Discharge pipe,
[0046] 3- Crushing mechanism, 31- Fixed plate, 311- Guide rail, 32- Moving grinding disc, 33- Fixed grinding disc, 331- Material guide channel, 34- Annular part, 341- Air hole
[0047] 4-First gas-solid separator, 41-Gas phase outlet of the first gas-solid separator, 42-Filter cloth, 43-Inlet pipe, 44-Solid phase outlet of the first gas-solid separator.
[0048] 51-Shell breaking tube, 52-Feeding tube,
[0049] 61-Mixer conveyor, 62-Branch pipe, 63-Nitrogen pipe,
[0050] 71-Second gas-solid separator, 72-Pressure relief pipe, 73-Buffer tank, 74-Recovery pipe, 75-Filter plate,
[0051] 8-Heat exchanger,
[0052] 9-Top cover of electrolytic cell, 91-Crust, 92-Flame opening. Detailed Implementation
[0053] In the following description, only certain exemplary embodiments are presented briefly. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention.
[0054] In the description of the embodiments of the present invention, it should be understood that the terms "center", "upper", "lower", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.
[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0056] In the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.
[0057] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0058] See Figures 1-3 This embodiment provides an electrolytic aluminum flue gas purification system, including a fume hood 1, a storage tank 2, a crushing mechanism 3, and a first gas-solid separator 4.
[0059] The smoke hood 1 is installed through the top cover 9 of the electrolytic cell and close to the fire port 92; the smoke hood 1 has a smoke exhaust pipe 11 and a feed pipe 12.
[0060] Storage tank 2 is used to store fresh alumina (i.e., alumina that has not reacted with HF); storage tank 2 is connected to feed pipe 12 via discharge pipe 21.
[0061] The crushing mechanism 3 is located inside the fume hood 1. The crushing mechanism 3 includes a fixed plate 31, a moving grinding disc 32, a fixed grinding disc 33, and a drive assembly (not shown in the figure).
[0062] The fixing plate 31 is fixed to the inner wall of the smoke hood 1; multiple fixing plates 31 are arranged in a circular array on the inner wall of the smoke hood 1.
[0063] The edge of the moving grinding disc 32 bends downward and then extends outward in the horizontal direction to form an annular part 34; the lower side of the annular part 34 is in rotatable contact with the upper side of the fixed plate 31; multiple air holes 341 are distributed on the annular part 34, and the fixed plate 31 is used to block the air holes 341. There are always some air holes 341 on the annular part 34 that are not blocked by the fixed plate 31.
[0064] The lower side of the annular portion 34 and the upper side of the fixed plate 31 are in rotatable contact as follows: the fixed plate 31 is provided with a guide rail 311, and the lower side of the annular portion 34 is provided with a sliding groove that matches the guide rail 311.
[0065] The fixed grinding disc 33 is fixed above the moving grinding disc 32, and the fixed grinding disc 33 and the moving grinding disc 32 are used together. The fixed grinding disc 33 has a material guiding channel 331. One end of the material guiding channel 331 is connected to the feed pipe 12, and the other end extends to the bottom of the fixed grinding disc 33 to guide fresh alumina in the storage tank 2 between the fixed grinding disc 33 and the moving grinding disc 32.
[0066] A drive assembly is used to rotate the movable grinding disc 32. In this embodiment, the movable grinding disc 32 is driven by electricity.
[0067] The working principle of the above-mentioned crushing mechanism 3 is as follows: after the fresh alumina in the storage tank 2 enters between the fixed grinding disc 33 and the moving grinding disc 32, it is crushed into alumina powder with smaller particle size and smoother shape under the cooperation of the fixed grinding disc 33 and the moving grinding disc 32.
[0068] The first gas-solid separator 4 has a gas phase outlet, a filter cloth 42, an inlet pipe 43 and a solid phase outlet arranged sequentially from top to bottom.
[0069] The gas phase outlet 41 of the first gas-solid separator is connected to the downstream purification equipment (not shown in the figure), which is used for deep purification of electrolysis flue gas.
[0070] Filter cloth 42 is used to separate the gas phase and the solid phase.
[0071] The inlet pipe 43 is connected to the exhaust pipe 11 via a delivery conduit, and the outlet of the inlet pipe 43 is bent upwards and faces the filter cloth 42.
[0072] The solid phase outlet 44 of the first gas-solid separator is used to discharge the separated solid phase.
[0073] The working principle of the above-mentioned electrolytic aluminum flue gas purification system is as follows:
[0074] Fresh alumina from storage tank 2 enters between fixed grinding disc 33 and moving grinding disc 32. Under the combined action of the fixed and moving grinding discs 33 and 32, it is pulverized into smaller, more rounded alumina powder. The fresh alumina powder falls into the vent 341 of the annular portion 34. When the vent 341 is blocked by the fixing plate 31, the fresh alumina powder remains in the vent 341. As the moving grinding disc 32 rotates, the fixing plate 31 is displaced from the vent 341, and the electrolytic flue gas in the electrolytic cell rises and passes through the vent 341, causing the fresh alumina powder to disperse. This allows it to adsorb HF from the electrolytic flue gas, resulting in fluorinated alumina powder. The fluorinated alumina powder and the electrolytic flue gas enter the first gas-solid separator 4 through the exhaust pipe 11, the conveying conduit, and the inlet pipe 43 to separate the gas and solid phases. The fluorinated alumina powder is collected at the bottom of the first gas-solid separator 4, ensuring that the electrolytic flue gas meets emission standards.
[0075] The electrolytic aluminum flue gas purification system also includes a shell-breaking pipe 51 and a feeding pipe 52.
[0076] The lower part of the shell-breaking tube 51 is hollow prism-shaped, while the middle and upper parts are cylindrical. The upper part of the shell-breaking tube 51 is slidably connected to the smoke hood 1, the middle part slides through the fixed grinding disc 33, and the lower part slides longitudinally through the moving grinding disc 32, enabling the moving grinding disc 32 to rotate. The shell-breaking tube 51 can move longitudinally and rotate around its own axis under the drive of the drive assembly. The rotating shell-breaking tube 51 can drive the moving grinding disc 32 to rotate. After the shell-breaking tube 51 acts downward on the crust 91 in the electrolytic cell (the crust 91 is a product in the electrolytic cell), a fire hole 92 is formed. The diameter of the lower end of the shell-breaking tube 51 gradually decreases.
[0077] The feeding pipe 52 is fixedly installed, and the outer wall of the feeding pipe 52 is longitudinally slidably connected to the inner wall of the shell breaking pipe 51. The upper end of the feeding pipe 52 is connected to the solid phase outlet 44 of the first gas-solid separator, so as to put the fluorine-containing alumina powder into the electrolyte from the fire port 92 of the shell 91 to reduce production costs.
[0078] The electrolytic aluminum flue gas purification system also includes a mixing conveyor 61, a branch pipe 62, and a nitrogen pipe 63.
[0079] The solid phase outlet 44 and the feed pipe 52 of the first gas-solid separator are connected by a mixing conveyor 61.
[0080] Branch pipe 62 is used to connect storage tank 2 and mixing conveyor 61.
[0081] Nitrogen pipe 63 is used to introduce nitrogen into mixing conveyor 61.
[0082] Fluorinated alumina powder and fresh alumina enter the mixing conveyor 61. Driven by nitrogen, the fluorinated alumina powder rubs against the fresh alumina to generate static electricity, causing the fluorinated alumina powder to be adsorbed onto the fresh alumina. In addition, because the fresh alumina has a larger particle size and irregular shape, it also has a certain physical adsorption effect on the fluorinated alumina powder. After the fluorinated alumina powder is adsorbed onto the fresh alumina, it is convenient to add it into the electrolyte in the electrolytic cell through the feeding pipe 52 and the shell breaking pipe 51.
[0083] This embodiment does not limit the movement trajectory and distance of fluorinated alumina powder and fresh alumina in the mixing conveyor 61.
[0084] The electrolytic aluminum flue gas purification system also includes a second gas-solid separator 71, a pressure relief pipe 72, a buffer tank 73, and a recovery pipe 74.
[0085] The second gas-solid separator 71 is configured with reference to the first gas-solid separator 4; the inlet of the second gas-solid separator 71 is connected to the outlet of the mixing conveyor 61, the gas phase outlet of the second gas-solid separator 71 is connected to the side wall of the buffer tank 73 through the pressure relief pipe 72, the pressure relief pipe 72 is equipped with a pressure relief valve (not shown in the figure), and the solid phase outlet of the second gas-solid separator 71 is connected to the inlet of the buffer tank 73.
[0086] One end of the recovery pipe 74 is connected to the side wall of the buffer tank 73, and the other end is connected to the discharge pipe 21. The inlet of the recovery pipe 74 is positioned opposite to the outlet of the pressure relief pipe 72, and a filter plate 75 is provided between them. The filter plate 75 is used to filter fresh alumina and the fluorine-containing alumina powder adsorbed on it. The fluorine-containing alumina powder that is not adsorbed on the fresh alumina can pass through the filter plate 75.
[0087] Considering that some fluorinated alumina powder may not be adsorbed onto fresh alumina, the above-mentioned second gas-solid separator 71, pressure relief pipe 72, buffer tank 73 and recovery pipe 74 are designed. After the fluorinated alumina powder and fresh alumina enter the buffer tank 73, the unadsorbed fluorinated alumina powder is transported back to the smoke collection hood 1 for utilization under the action of nitrogen gas blown out by the pressure relief pipe 72.
[0088] The electrolytic aluminum flue gas purification system also includes a heat exchanger 8. The delivery pipe and nitrogen pipe 63 exchange heat through the heat exchanger 8 to heat the nitrogen entering the system and reduce heat loss caused by the low-temperature nitrogen entering the electrolytic cell.
[0089] Based on the above, the electrolytic aluminum flue gas purification system described above has at least the following beneficial effects:
[0090] 1. Fresh alumina is crushed into smaller and more rounded alumina powder. The fresh alumina powder falls into the vent 341 of the annular part 34. When the vent 341 is blocked by the fixing plate 31, the fresh alumina powder remains in the vent 341. As the moving grinding disc 32 rotates, the fixing plate 31 is displaced from the vent 341. The electrolytic flue gas in the electrolytic cell rises and passes through the vent 341, causing the fresh alumina powder to be sprayed out and fully contact the HF in the electrolytic flue gas, thereby ensuring the adsorption effect of HF.
[0091] Second, the vent 341 blocked by the fixing plate 31 can retain a large amount of fresh alumina powder, thereby increasing the amount of fresh alumina powder used for HF adsorption (more fresh alumina powder in contact with the electrolytic flue gas), thus ensuring the effect of HF adsorption.
[0092] Third, during the rotation of the moving grinding disc 32, only some of the air holes 341 are open at the same time, and the gas flow is relatively small, which helps to reduce or limit the exhaust volume, thereby reducing heat loss in the electrolytic cell.
[0093] Fourth, crushing fresh alumina into smaller and smoother-shaped powder can reduce wear on the conveying conduit (the fresh alumina in storage tank 2 has a large particle size and irregular shape, which causes great wear on the conveying conduit).
[0094] Fifth, crushing fresh alumina into smaller and smoother-shaped powder can reduce the impact on filter cloth 42 and improve its service life.
[0095] 6. Fluorine-containing alumina powder and fresh alumina are fed into the mixing conveyor 61. Under the drive of nitrogen, the fluorine-containing alumina powder and fresh alumina rub against each other to generate static electricity, causing the fluorine-containing alumina powder to be adsorbed onto the fresh alumina. In addition, since the fresh alumina has a larger particle size and irregular shape, it also has a certain physical adsorption effect on the fluorine-containing alumina powder. After the fluorine-containing alumina powder is adsorbed onto the fresh alumina, it is convenient to add it into the electrolyte in the electrolytic cell through the feeding pipe 52 and the shell breaking pipe 51.
[0096] VII. Considering that some fluorinated alumina powder may not be adsorbed onto fresh alumina, the aforementioned second gas-solid separator 71, pressure relief pipe 72, buffer tank 73, and recovery pipe 74 were designed. After the fluorinated alumina powder and fresh alumina enter the buffer tank 73, the unadsorbed fluorinated alumina powder is transported back to the fume hood 1 for utilization under the action of nitrogen gas blown out by the pressure relief pipe 72. In addition, nitrogen gas is introduced between the fixed grinding disc 33 and the moving grinding disc 32 to purge the powder located between the fixed grinding disc 33 and the moving grinding disc 32, causing the powder to fall into the air holes 341 of the annular portion 34.
[0097] 8. The delivery conduit and nitrogen pipe 63 exchange heat through the heat exchanger 8 to heat the nitrogen entering the system and reduce heat loss caused by the low-temperature nitrogen entering the electrolytic cell.
[0098] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Without conflict, the embodiments and features described in the embodiments of this application can be arbitrarily combined with each other. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A flue gas purification system for electrolytic aluminum, characterized in that, include: A smoke hood is installed through the top cover of the electrolytic cell and near the fire port; the smoke hood has a smoke exhaust pipe and a feed pipe. Storage tanks are used to store fresh alumina; The storage tank is connected to the feed pipe via a discharge pipe; The pulverizing mechanism is located inside the smoke hood; First gas-solid separator; The crushing mechanism includes: A fixing plate is fixed to the inner wall of the smoke collection hood; The moving grinding disc has its edge bent downwards and then extends outwards in the horizontal direction to form an annular part; the lower side of the annular part is in rotatable contact with the upper side of the fixed plate; multiple air holes are distributed on the annular part, and the fixed plate is used to seal the air holes, and there are always some air holes on the annular part that are not sealed by the fixed plate. A fixed grinding disc is fixed above the movable grinding disc, and the fixed grinding disc and the movable grinding disc are used together; the fixed grinding disc has a material guiding channel, one end of which is connected to the feed pipe and the other end extends to the bottom of the fixed grinding disc; A drive assembly for rotating the moving grinding disc.
2. The electrolytic aluminum flue gas purification system according to claim 1, characterized in that, A filter cloth is provided between the gas phase outlet and the solid phase outlet of the first gas-solid separator, and an inlet pipe is provided between the filter cloth and the solid phase outlet of the first gas-solid separator. The inlet pipe is connected to the exhaust pipe through a delivery conduit.
3. The electrolytic aluminum flue gas purification system according to claim 2, characterized in that, The outlet of the inlet pipe is bent upwards and faces the filter cloth.
4. The electrolytic aluminum flue gas purification system according to claim 1, characterized in that, The fixed plate is provided with a guide rail, and the lower side of the annular part is provided with a sliding groove that matches the guide rail.
5. The electrolytic aluminum flue gas purification system according to claim 1, characterized in that, Also includes: The shell-breaking tube is used to create a crater at the shell formation point inside the electrolytic cell and can drive the moving grinding disc to rotate. A fixed feeding pipe has its outer wall slidably connected to the inner wall of the shell-breaking pipe in a longitudinal direction, and the upper end of the feeding pipe is connected to the solid phase outlet of the first gas-solid separator.
6. The electrolytic aluminum flue gas purification system according to claim 5, characterized in that, The lower part of the shell-breaking tube is hollow prism-shaped, and the middle and upper parts are cylindrical. The upper part of the shell-breaking tube is slidably connected to the smoke collection hood, the middle part slides through the fixed grinding disc, and the lower part slides longitudinally through the moving grinding disc and can drive the moving grinding disc to rotate.
7. The electrolytic aluminum flue gas purification system according to claim 5, characterized in that, The diameter of the lower end of the shell-breaking tube gradually decreases.
8. The electrolytic aluminum flue gas purification system according to claim 5, characterized in that, Also includes: A mixing conveyor, wherein the solid phase outlet of the first gas-solid separator and the feed pipe are connected through the mixing conveyor; Branch pipes are used to connect the storage tank and the mixing conveyor; A nitrogen pipe is used to introduce nitrogen into the mixing conveyor. Fluorine-containing alumina powder is driven by nitrogen gas and rubs against fresh alumina to generate static electricity, causing the fluorine-containing alumina powder to be adsorbed onto the fresh alumina.
9. The electrolytic aluminum flue gas purification system according to claim 8, characterized in that, It also includes a second gas-solid separator, a pressure relief pipe, a buffer tank, and a recovery pipe; The inlet of the second gas-solid separator is connected to the outlet of the mixing conveyor, and the gas phase outlet of the second gas-solid separator is connected to the side wall of the buffer tank through a pressure relief pipe; One end of the recovery pipe is connected to the side wall of the buffer tank, and the other end is connected to the discharge pipe; the inlet of the recovery pipe and the outlet of the pressure relief pipe are arranged opposite to each other, and a filter plate is arranged between them. The filter plate is used to filter fresh alumina, and fluorine-containing alumina powder can pass through the filter plate.
10. The electrolytic aluminum flue gas purification system according to claim 9, characterized in that, It also includes a heat exchanger through which the electrolytic flue gas and the nitrogen pipe exchange heat.