Method and device for extracting germanium from germanium tetrafluoride production tail gas absorption liquid

Abstract

The invention discloses a method and device for extracting germanium from germanium tetrafluoride production tail gas absorption liquid, and belongs to the technical field of semiconductor germanium material production processes. The device comprises a concentration and distillation reaction kettle, a stirrer, a heater, a condenser, a multi-stage absorber, an air draft system and a spray tower. The device is used for stirring, concentrating and distilling for three times to extract germanium, the rotating speed of a stirrer for the first time is 60 r / min-200 r / min, the heating and distilling temperature is 90-100 DEG C, boric acid is added for the second time, the heating and distilling temperature is raised to 100-115 DEG C, industrial hydrochloric acid is added for the third time, and the distilling temperature is 100-120 DEG C. After concentration and distillation are completed, a concentrated solution is collected and sampled, the fluorine content and the germanium content in the concentrated solution are analyzed, and the result shows that the recovery rate of germanium in the method reaches 98% or above, and the fluorine content in germanium tetrachloride obtained through distillation is lower than 0.3% and does not exceed the requirement of the germanium tetrachloride product standard. And the method can be used for producing a high-purity germanium tetrachloride product in the next step of rectification and purification.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor germanium material production technology, and particularly relates to a method and device for extracting germanium from tail gas absorption liquid produced by high-purity germanium tetrafluoride. Background Art

[0002] Germanium tetrafluoride (GF4) is a fluoride of germanium, typically prepared by reacting fluorine gas with germanium metal. It can also be prepared by reacting high-purity germanium dioxide with hydrogen fluoride to produce barium fluorogermanate, followed by thermal decomposition at 800°C. Germanium tetrafluoride is primarily used to produce stable isotopes of germanium-72 and germanium-76. In the semiconductor industry, it is primarily used as a chemical dopant and ion implanter, as well as in high-purity germanium detectors for dark matter detection. Electronic-grade GF4-72 isotope is used as an etching and performance optimization chemical for the production of DRAM chips within the 10 nm range. Single crystals of GF4-76 are used as tracer atoms in high-energy physics dark matter detection.

[0003] During the production and use of germanium tetrafluoride, a large amount of sulfuric acid absorption liquid containing germanium and fluorine is generated. Currently, the main methods for treating germanium-containing and fluorine-containing absorption liquids include extraction and precipitation. For example, patent application number CN201811059018.3 discloses a process for recovering germanium from waste acid used in the deep processing of germanium wafers. However, this method is only applicable to germanium-containing waste liquids with low fluorine and germanium content, and the germanium recovery rate is low. Patent application number CN201710131082.7 discloses a process for recovering germanium from germanium-containing and fluorine-containing etching liquids by adding boric acid and silicon dioxide, heating and volatilizing, removing fluorine, and precipitating and enriching germanium to recover germanium metal. Patent application number CN201010191424.2 discloses a method for recovering germanium from organic germanium waste liquid by using magnesium chloride-calcium oxide precipitation to recover germanium. The above methods have achieved the goal of germanium recovery to a certain extent. However, since germanium tetrafluoride produces germanium dioxide, fluorogermanic acid, and hydrofluoric acid when it comes into contact with water, the fluorine content in the recovered concentrate is too high. During the distillation process to recover germanium, fluorine causes serious corrosion to the equipment, posing a significant safety hazard. In addition, the existing process using chemical precipitation of germanium has problems such as high reagent dosage, high cost, low automation, long time consumption, low quality of the resulting germanium concentrate, large amount of residual liquid generated during the chlorination distillation process, and low germanium recovery rate. Therefore, there is an urgent need to research and develop a method for recovering germanium from tail gas absorption liquid in germanium tetrafluoride production that is simple, time-saving, highly automated, easy to operate, and has a high recovery rate. Summary of the Invention

[0004] The present invention provides a method and device for extracting germanium from tail gas absorption liquid produced in the production of germanium tetrafluoride. The purpose is to provide a safe and efficient concentrated distillation method and device for recovering germanium from a fluorine-containing and germanium-containing solution, which is used to extract germanium from the tail gas absorption liquid generated in the production process of germanium tetrafluoride.

[0005] A device for extracting germanium from tail gas absorption liquid produced by germanium tetrafluoride, characterized by comprising a concentrated distillation reactor, an agitator, a circulation heater, a condenser, a multi-stage absorber, an exhaust system, and a spray tower, wherein the concentrated distillation reactor comprises a bracket, a jacket, and an inner reactor, wherein the jacket is mounted on the bracket, a drain port is provided at the bottom of the inner reactor and leads to the outside of the jacket, an oil inlet is provided at the lower portion of the outer wall of the jacket, an oil outlet is provided at the upper portion of the outer wall, the jacket is open at the top, the inner reactor is mounted within the jacket, a feed port and a discharge port are provided at the top of the inner reactor, the agitator comprises a motor, a stirring blade, and a connecting rod, wherein the motor is mounted at the top of the inner reactor, the upper portion of the connecting rod is connected to the motor and extends into the inner reactor, the bottom of the connecting rod is mounted with a stirring blade, and valves are provided for the drain port, the feed port, and the discharge port. The circulation heater is provided with a liquid outlet pipe and a liquid inlet pipe, the liquid outlet pipe port is connected to the oil inlet port of the jacket, and the liquid inlet pipe port is connected to the oil outlet port of the jacket; The discharge port of the inner kettle is connected to the condenser, multi-stage absorber, exhaust system and spray tower in sequence through pipelines; The method for extracting germanium from tail gas absorption liquid in germanium tetrafluoride production using the device is characterized by: S1- Determine the contents of germanium and fluorine in the germanium tetrafluoride tail gas absorption liquid, add the germanium tetrafluoride tail gas absorption liquid to the inner kettle, heat to boiling and stir, the stirrer speed is 60 r / min~200 r / min, the heating temperature is 90℃~100℃, and when the absorption liquid temperature reaches 100℃, concentrate for 2 hours, and remove the water and hydrogen fluoride volatilized after the absorption liquid boils through the exhaust system to obtain a primary concentrated liquid; S2- Determine the fluorine content in the primary concentrate, calculate the fluorine mass, and then add boric acid 1 to 2.5 times the fluorine mass. The boric acid reacts with hydrogen fluoride and fluorogermanic acid to generate boron trifluoride gas and germanium dioxide precipitate. Heat and volatilize to remove water and boron trifluoride gas. The chemical reaction equation is: (1) H3BO3+3HF→BF3↑+3H2O; (2) H2GeF6+2H3BO3→2BF3↑+GeO2+4H2O; After the addition is completed, the temperature of the inner kettle is raised to 100 ℃ ~ 115 ℃, and heating is continued to evaporate the water, hydrogen fluoride and boron trifluoride in the primary concentrate.

[0006] At this time, the germanium in the primary concentrate exists in the form of germanium dioxide precipitate and germanium sulfate; S3-When the primary concentrate is concentrated to 1 / 4 of its original volume, a secondary concentrate is obtained. After stopping heating and cooling, the inner kettle is rinsed with pure water from the feed port to wash off the germanium dioxide and germanium sulfate attached to the kettle wall. After the kettle wall is rinsed clean, industrial hydrochloric acid with a volume of 1 to 4 times that of the secondary concentrate is added. The feed port valve is closed, the discharge port valve and the condenser circulating cooling water valve are opened, and the circulating heater is turned on to continue heating to boiling. The temperature rises to 100 ℃ to 120 ℃ and distilled for 2h to 3h. During the distillation process, the germanium in the primary concentrate reacts with the hydrochloric acid to form germanium tetrachloride, which is then distilled out, cooled and collected to obtain germanium tetrachloride. The chemical reaction equation is as follows: (1) GeO2+4HCl→GeCl4↑+2H2O; (2) Ge(SO4)2+4HCl→GeCl4↑+2H2SO4; (3) H2GeF6+4HCl→GeCl4↑+6HF.

[0007] S4-After separation by distillation, the germanium dioxide, germanium sulfate and fluorogermanic acid in the secondary concentrated liquid are distilled and volatilized in the form of germanium tetrachloride to the condenser for cooling to form germanium tetrachloride liquid which flows into the absorption bottle; after the distillation is completed, the heating is stopped, and the inner wall of the inner kettle is rinsed with clean water to rinse the residual distillation liquid on the inner wall of the inner kettle; the residual distillation liquid is discharged from the drain port.

[0008] Furthermore, the inner kettle, stirring blades and connecting rods are all made of polytetrafluoroethylene.

[0009] Preferably, boric acid in an amount 1.5 times the mass of fluorine in the germanium tetrafluoride tail gas absorption liquid is added to S2.

[0010] Preferably, industrial hydrochloric acid in an amount 4 times the volume of the absorption liquid is added to S3.

[0011] The beneficial effects of the present invention are that, since germanium tetrafluoride produces germanium dioxide, fluorogermanic acid, and hydrofluoric acid upon contact with water, the high fluorine content in the absorption liquid can cause significant corrosion to equipment during the distillation and recovery of germanium. The highly stable inner kettle of the device serves as an optimal reaction vessel for defluorination and germanium extraction, thus resolving the significant damage to equipment caused by the handling of the germanium tetrafluoride tail gas absorption liquid. This method achieves a fluorine removal rate exceeding 99%. After defluorination, the product can be directly recovered by chlorination and distillation to produce germanium tetrachloride. Further distillation, purification, and hydrolysis can produce high-purity germanium dioxide. The resulting distillation residue contains a germanium content of 10 mg / L to 50 mg / L. After lime neutralization and treatment to meet product standards, it can be discharged. Results demonstrate that this method achieves a germanium recovery rate exceeding 98%, and the fluorine content of the distilled germanium tetrachloride is less than 0.3%, meeting the product standard for germanium tetrachloride, allowing for further distillation and purification to recover the germanium.

[0012] Currently, other methods for recovering germanium-containing and fluorine-containing absorbents contain high fluorine content in the concentrate. Fluorine severely corrodes equipment during the distillation process to recover germanium, posing a significant safety hazard. Furthermore, the treated wastewater still contains a significant amount of germanium that cannot be recovered, resulting in a germanium recovery rate of less than 95%. Furthermore, the recovery process is long and complex, requiring significant energy investment in subsequent recovery processes, resulting in high costs for the recovery of germanium-containing and fluorine-containing wastewater. Compared to existing methods for recovering germanium-containing and fluorine-containing wastewater, this method significantly improves both fluorine removal and germanium recovery rates, eliminates corrosion damage to equipment, and simplifies the recovery process, alleviating the high energy costs associated with the treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The figure is a schematic diagram of the connection of a device for extracting germanium from tail gas absorption liquid in the production of germanium tetrafluoride.

[0014] Figure 2 Schematic diagram of the structure of the concentration distillation reactor.

[0015] Figure 3 The present invention is a flow chart of a method for extracting germanium from tail gas absorption liquid in the production of germanium tetrafluoride.

[0016] Among them: 1-concentration distillation reactor, 11-inner kettle, 12-jacket, 13-support, 14-feed port, 15-discharge port, 16-oil inlet, 17-oil outlet, 18-drain port, 2-agitator, 21-motor, 22-stirring fan blades, 23-connecting rod, 3-circulation heater, 4-condenser, 5-multi-stage absorber, 6-exhaust system, 7-spray tower. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0018] Example 1: An apparatus for extracting germanium from tail gas absorbent in the production of germanium tetrafluoride, comprising a concentration and distillation reactor 1, an agitator 2, a circulating heater 3, a condenser 4, a multi-stage absorber 5, an exhaust system 6, and a spray tower 7. The concentration and distillation reactor 1 comprises a support 13, a jacket 12, and an inner kettle 11. The jacket 12 is mounted on the support 13. The inner kettle 11 has a drain port 18 at its bottom extending to the exterior of the jacket 12. The jacket 12 has an oil inlet 16 at its lower outer wall and an oil outlet 17 at its upper outer wall. The jacket 12 has an open top, and the inner kettle 11 is mounted within the jacket 12. The inner kettle 11 has a feed inlet 14 and a discharge port 15 at its top. The agitator 2 consists of a motor 21, a stirring blade 22 and a connecting rod 23. The motor 21 is installed on the top of the inner kettle 11. The upper part of the connecting rod 23 is connected to the motor 21 and extends into the inner kettle 11. The stirring blade 22 is installed at the bottom of the connecting rod 23. The drain port 18, the feed port 14 and the discharge port 15 are all provided with valves. The circulating heater 3 is equipped with a liquid outlet and a liquid inlet pipe. The outlet is connected to the oil inlet 16 of the jacket 12, and the inlet is connected to the oil outlet 17 of the jacket 12. The discharge port 15 of the inner kettle 11 is connected to the condenser 4 via a pipe. The condenser 4 is further connected to the multi-stage absorber 5 via a pipe. The multi-stage absorber 5 is equipped with a low-level pipe and a high-level pipe. The low-level pipe extends to the bottom of the bottle, and the high-level pipe extends deep into the top of the bottle. There are four multi-stage absorbers in series. The first receives the distilled and condensed germanium tetrachloride liquid from the inner kettle 11. The second and third are each filled with pure water to half the bottle's capacity, and the fourth is filled with sodium hydroxide solution with a mass concentration of 10% to half the bottle's capacity. The high-level pipe of the last multi-stage absorber is connected to the exhaust system 6, which is then connected to the spray tower 7. The jacket 12 and bracket 13 are both made of stainless steel. The jacket 12 is a hollow structure with heat transfer oil flowing inside and is wrapped with insulation material to provide the required constant temperature environment for the fluorine removal and germanium extraction reaction. The inner kettle 11, stirring blades 22 and connecting rods 23 are all made of corrosion-resistant polytetrafluoroethylene. The inner kettle 11 serves as the main container for the defluorination and germanium extraction reaction. It has an inner diameter of 800 mm, a height of 1000 mm, and a thickness of 5 mm. There are volume scale lines on the inner wall, which makes it easy to observe the volume of the solution in the kettle during use.

[0019] The method for extracting germanium from tail gas absorption liquid in germanium tetrafluoride production using the device comprises the following steps: S1, turn on the exhaust system, take 100 L of germanium tetrafluoride production tail gas absorption liquid with a germanium content of 40.65 g / L and a fluorine content of 60.63 g / L, pour it into the inner kettle 11 from the feed port 14, turn on the stirrer 2 and adjust the stirring rate to 150 r / min, turn on the circulation heater 3 and set the evaporation temperature to 100 ° C to start the first concentration, when the temperature reaches 100 ° C after concentrating for 2 hours, when the first concentration is completed, stop heating, and remove the water and hydrogen fluoride evaporated after the absorption liquid boils through the exhaust system. After the temperature is cooled to room temperature, the first concentrated liquid is obtained with a volume of approximately 50 L.

[0020] S2, after the first concentration, most of the water and a part of the hydrogen fluoride in the absorption liquid are volatilized. At this time, the fluorine content in the primary concentrated liquid is measured, and it is calculated that the mass of fluorine is about 6 kg. The attachments on the wall of the inner kettle 11 are washed off with pure water from the feed port 14, and 9 kg of boric acid is added. The agitator 2 is turned on and the stirring rate is adjusted to 100 r / min. The circulation heater 3 is turned on and the temperature is set to 110 ° C to start the second concentration. After the temperature reaches 110 ° C, the concentration is continued for 4 hours. After the second concentration is completed, a secondary concentrated liquid is obtained with a volume of about 25 L. After the temperature of the secondary concentrated liquid is cooled to room temperature, a sample is taken to analyze and detect the germanium content and fluorine content therein. The test results are that the germanium content is 162.5 g / L and the fluorine content is 0.03 g / L.

[0021] S3, add hydrochloric acid to start distillation; rinse the attachments on the inner wall of the inner kettle 11 with pure water from the feed port 14, add 100 L of industrial hydrochloric acid, close the valve of the feed port 14, turn on the stirrer 2 and adjust the stirring rate to 80 r / min, turn on the circulation heater 3 and set the temperature to 110 ° C. When the temperature reaches 110 ° C, open the condenser 4 and the discharge port 15 valve, and start distillation to recover germanium tetrachloride for 3 hours.

[0022] S4, after the distillation is completed, the circulation heater 3 and the agitator 2 are closed, and the discharge port 15 valve and the condenser 4 are closed after the internal temperature of the inner kettle 11 is cooled to room temperature. The feed port 14 valve is opened and the attachments on the inner wall of the inner kettle 11 are flushed down with clean water, and the attachments are discharged from the drain port 18. The distillation residue is collected by a container, and its volume is measured to be 21.58 L. The germanium content and fluorine content are detected by sampling. After detection, it is concluded that the germanium content is 0.02 g / L and the fluorine content is 6.65 g / L. The germanium tetrachloride liquid received in the multi-stage absorber 5 is transferred with a container, and its volume is measured to be 6.38 L. The germanium content and fluorine content are detected by sampling. After detection, it is concluded that the germanium content is 33.30% and the fluorine content is 0.30%.

[0023] Example 2: Using the same apparatus, a second distillation and concentration step was performed. The specific steps were as follows: S1, turn on the exhaust system, take 100 L of germanium tetrafluoride production tail gas absorption liquid with a germanium content of 40.65 g / L and a fluorine content of 60.63 g / L, pour it into the inner kettle 11 from the feed port 14, turn on the stirrer 2 and adjust the stirring rate to 150 r / min, turn on the circulation heater 3 and set the evaporation temperature to 100 ° C to start the first concentration, when the temperature reaches 100 ° C after concentrating for 2 hours, when the first concentration is completed, stop heating, and remove the water and hydrogen fluoride evaporated after the absorption liquid boils through the exhaust system. After the temperature is cooled to room temperature, the first concentrated liquid is obtained with a volume of approximately 50 L.

[0024] S2, after the first concentration, most of the water and a part of the hydrogen fluoride in the absorption liquid are volatilized. At this time, the fluorine content in the primary concentrated liquid is measured, and it is calculated that the mass of fluorine is about 6 kg. The attachments on the wall of the inner kettle 11 are washed off with pure water from the feed port 14, and 6 kg of boric acid is added. The agitator 2 is turned on and the stirring rate is adjusted to 100 r / min. The circulation heater 3 is turned on and the temperature is set to 110 ° C to start the second concentration. After the temperature reaches 110 ° C, the concentration is continued for 4 hours. After the second concentration is completed, a secondary concentrated liquid is obtained with a volume of about 25 L. After the temperature of the secondary concentrated liquid is cooled to room temperature, a sample is taken to analyze and detect the germanium content and fluorine content therein. The test results show that the germanium content is 161.9 g / L and the fluorine content is 0.05 g / L.

[0025] S3, add hydrochloric acid to start distillation; rinse the attachments on the inner wall of the inner kettle 11 with pure water from the feed port 14, add 100 L of industrial hydrochloric acid, close the valve of the feed port 14, turn on the stirrer 2 and adjust the stirring rate to 80 r / min, turn on the circulation heater 3 and set the temperature to 110 ° C. When the temperature reaches 110 ° C, open the condenser 4 and the discharge port 15 valve, and start distillation to recover germanium tetrachloride for 3 hours.

[0026] S4, after the distillation is completed, the circulation heater 3 and the agitator 2 are turned off, and the discharge port 15 valve and the condenser 4 are closed after the internal temperature of the inner kettle 11 is cooled to room temperature. The feed port 14 valve is opened and the attachments on the inner wall of the inner kettle 11 are flushed down with clean water, and the attachments are discharged from the drain port 18. The distillation residue is received by a container, and its volume is measured to be 21.58 L. The germanium content and fluorine content are detected by sampling. After detection, it is concluded that the germanium content is 0.04 g / L and the fluorine content is 10.03 g / L. The germanium tetrachloride liquid received in the multi-stage absorber 5 is transferred with a container, and its volume is measured to be 6.24 L. The germanium content and fluorine content are detected by sampling. After detection, it is concluded that the germanium content is 33.30% and the fluorine content is 0.46%.

[0027] Comparing Example 1 with Example 2, in Example 1, boric acid in an amount 1.5 times the mass of fluorine in the germanium tetrafluoride production tail gas absorption liquid was added during the second concentration, while in Example 2, the amount was 1 times. When the germanium content and fluorine content in the absorption liquid were the same, the fluorine content in the finally collected germanium tetrachloride liquid was lower when the boric acid in an amount 1.5 times the mass of fluorine was added, and the germanium content and fluorine content in the discharged distillation residue were also lower.

Claims

1. A device for extracting germanium from tail gas absorption liquid produced by germanium tetrafluoride production, characterized in that: The invention comprises a concentrated distillation reactor, an agitator, a heater, a condenser, a multi-stage absorber, an exhaust system and a spray tower, wherein the concentrated distillation reactor comprises a bracket, a jacket and an inner kettle, the jacket is mounted on the bracket, a drain port is provided at the bottom of the inner kettle and leads to the outside of the jacket, an oil inlet is provided at the lower part of the outer wall of the jacket, an oil outlet is provided at the upper part of the outer wall, the top of the jacket is open, the inner kettle is mounted in the jacket, a feed port and a discharge port are provided at the top of the inner kettle, the agitator consists of a motor, a stirring blade and a connecting rod, the motor is mounted on the top of the inner kettle, the upper part of the connecting rod is connected to the motor and extends into the inner kettle, the bottom of the connecting rod is equipped with a stirring blade, and the drain port, the feed port and the discharge port are all provided with valves; The circulation heater is provided with a liquid outlet pipe and a liquid inlet pipe, the liquid outlet pipe port is connected to the oil inlet port of the jacket, and the liquid inlet pipe port is connected to the oil outlet port of the jacket; The discharge port of the inner kettle is connected to the condenser, multi-stage absorber, exhaust system and spray tower in sequence through pipelines; A method for extracting germanium from tail gas absorption liquid in germanium tetrafluoride production using the device is characterized by comprising the following steps: S1- Determine the contents of germanium and fluorine in the germanium tetrafluoride tail gas absorption liquid, add the germanium tetrafluoride tail gas absorption liquid to the inner kettle, heat to boiling and stir, the stirrer speed is 60 r / min ~ 200 r / min, the heating temperature is 90 ℃ ~ 100 ℃, and when the absorption liquid temperature reaches 100 ℃, concentrate for 2 hours, and remove the water and hydrogen fluoride volatilized after the absorption liquid boils through the exhaust system to obtain a primary concentrated liquid; S2- Determine the fluorine content in the primary concentrate, calculate the fluorine mass, and then add boric acid at a mass of 1 to 2.5 times the fluorine mass. The boric acid reacts with hydrogen fluoride and fluorogermanic acid to generate boron trifluoride gas and germanium dioxide precipitate. Heat and volatilize to remove water and boron trifluoride gas. The chemical reaction equation is: (1) H3BO3+3HF→BF3↑+3H2O; (2) H2GeF6+2H3BO3→2BF3↑+GeO2+4H2O; After the addition is complete, raise the temperature of the inner kettle to 100°C to 115°C and continue heating to evaporate the water, hydrogen fluoride and boron trifluoride in the primary concentrate; At this time, the germanium in the primary concentrate exists in the form of germanium dioxide precipitate and germanium sulfate; S3-When the primary concentrate is concentrated to 1 / 4 of its original volume, a secondary concentrate is obtained. After stopping heating and cooling, the inner kettle is rinsed with pure water from the feed port to wash off the germanium dioxide and germanium sulfate attached to the kettle wall. After the kettle wall is rinsed clean, industrial hydrochloric acid with a volume of 1 to 4 times that of the secondary concentrate is added. The feed port valve is closed, the discharge port valve and the condenser circulating cooling water valve are opened, and the circulating heater is turned on to continue heating to boiling. The temperature rises to 100 ℃ ~ 120 ℃ and distilled for 2 h ~ 3 h. During the distillation process, the germanium in the primary concentrate reacts with the hydrochloric acid to form germanium tetrachloride, which is then distilled and cooled to obtain germanium tetrachloride. The chemical reaction equation is as follows: (1) GeO2+4HCl→GeCl4↑+2H2O; (2) Ge(SO4)2+4HCl→GeCl4↑+2H2SO4; (3) H2GeF6+4HCl→GeCl4↑+6HF; S4-After separation by distillation, the germanium dioxide, germanium sulfate and fluorogermanic acid in the secondary concentrated liquid are distilled and volatilized in the form of germanium tetrachloride to the condenser for cooling to form germanium tetrachloride liquid which flows into the absorption bottle; after the distillation is completed, the heating is stopped, and the inner wall of the inner kettle is rinsed with clean water to rinse the residual distillation liquid on the inner wall of the inner kettle; the residual distillation liquid is discharged from the drain port.

2. The device for extracting germanium from tail gas absorption liquid produced by germanium tetrafluoride according to claim 1, characterized in that The inner kettle, stirring blades and connecting rods are all made of polytetrafluoroethylene.

3. A method for extracting germanium from tail gas absorption liquid produced by germanium tetrafluoride according to claim 1, characterized in that Boric acid having a mass of 1.5 times that of fluorine in the germanium tetrafluoride tail gas absorption liquid is added to the S2.

4. A method for extracting germanium from tail gas absorption liquid produced by germanium tetrafluoride as claimed in claim 1, characterized in that Industrial hydrochloric acid 4 times the volume of the absorption liquid is added to S3.

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