Production method for producing anhydrous hydrogen fluoride by using fluorine-containing waste gas

Abstract

The invention discloses a production method for producing anhydrous hydrogen fluoride by using fluorine-containing waste gas, relates to the field of chemical production, and discloses a production method for producing anhydrous hydrogen fluoride by using fluorine-containing waste gas, which comprises the following steps: waste gas quality detection: firstly filtering and drying the waste gas, and then detecting the fluorine-containing waste gas, specific components and contents of fluorides are determined, and a basis is provided for subsequent procedures; and mixing the absorbent with the fluorine-containing waste gas: conveying the detected waste gas to an absorption tower, and mixing the waste gas with the absorbent in the absorption tower so as to produce the anhydrous hydrogen fluoride. In the mixing process of the absorbent and the fluorine-containing waste gas, a proper absorbent combination is selected according to the components of the waste gas, the pertinence is strong, and the yield of anhydrous hydrogen fluoride produced by the fluorine-containing waste gas is ensured while the adaptability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of chemical production, and in particular to a production method for producing anhydrous hydrogen fluoride by utilizing fluorine-containing waste gas. Background Art

[0002] In the production process of many industrial fields such as metallurgy and chemical industry, a large amount of fluorine-containing waste gas is generated. These waste gases contain rich fluoride resources, such as hydrogen fluoride, fluorosilicic acid, etc. However, if not properly handled, these fluorine-containing waste gases will cause serious pollution to the environment.

[0003] Anhydrous hydrogen fluoride is an important chemical raw material, widely used in many fields. In the fluorine chemical industry, anhydrous hydrogen fluoride is a key raw material for the production of fluororesins, fluororubbers, refrigerants and other products. With the continuous development of science and technology and the progress of industry, the demand for anhydrous hydrogen fluoride is also increasing. At the same time, people have found that fluorine-containing waste gas can be used to produce anhydrous hydrogen fluoride, which solves the problem of waste gas discharge and saves production costs.

[0004] Considering the use of fluorine-containing waste gas in the production of anhydrous hydrogen fluoride, due to the complex fluoride composition in the fluorine-containing waste gas and the presence of some fluoride forms that are difficult to convert, the reaction is incomplete, reducing the fluorine recovery rate and the output of anhydrous hydrogen fluoride. At the same time, in the reaction of fluoride salts with concentrated sulfuric acid, the reaction speed may be slow or the reaction may be incomplete due to improper control of reaction conditions, such as temperature, pressure, reactant concentration and other factors, affecting production efficiency. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a production method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas, which solves the problem that in the process of producing anhydrous hydrogen fluoride using fluorine-containing waste gas, the complex fluoride components in the fluorine-containing waste gas lead to incomplete reaction and reduce the output of anhydrous hydrogen fluoride.

[0006] To achieve the above object, the present invention is implemented by the following technical scheme: a production method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas, comprising the following steps: S1. Waste gas quality detection: It is necessary to first filter and dry the waste gas, and then detect the fluorine-containing waste gas to determine the specific composition and content of fluoride in it, providing a basis for subsequent processes; S2. Mixing the absorbent with the fluorine-containing waste gas: transmitting the detected waste gas to the absorption tower, so that the waste gas and the absorbent are mixed in the absorption tower, thereby producing anhydrous hydrogen fluoride; S3. Salt conversion: The fluoride salts obtained after absorption are discharged from the bottom of the absorption tower and sent to a reactor, in which concentrated sulfuric acid is added to react with the fluoride salts; S4. Exhaust gas cooling: The gas coming out of the reactor contains hydrogen fluoride and a small amount of impurity gas and moisture. First, the gas is cooled to 10-20℃ by a cooler to condense the hydrogen fluoride into liquid; S5. Distillation tower purification: The condensed hydrogen fluoride liquid is sent to a distillation tower for distillation purification.

[0007] Preferably, step S1 includes: S101. Waste gas filtration: install a multi-stage filtration device, pass the fluorine-containing waste gas through the multi-stage filtration device, and set a coarse filter, a medium-efficiency filter, and a high-efficiency filter in the multi-stage filtration device; S102. Waste gas drying: First, the waste gas is passed through a drying tower filled with concentrated sulfuric acid, and the concentrated sulfuric acid reacts with the moisture in the waste gas to remove most of the moisture. Then, calcium chloride solid desiccant is used for deep drying. The waste gas dried with concentrated sulfuric acid is passed through a drying box filled with calcium chloride particles to further remove the residual moisture. S103. Waste gas detection: The gas composition analyzer can accurately detect the types and contents of various fluorides in the waste gas. Common fluorides include hydrogen fluoride, fluorosilicic acid, sodium fluorosilicate, etc.

[0008] Preferably, in step S101, larger particles of impurities are filtered out through a coarse filter, the pore size of the coarse filter can be set to 1-2 mm, and then a medium-efficiency filter is used to further remove tiny particles, and the filtering accuracy of the medium-efficiency filter can be set between 0.1-0.5 mm. Finally, a high-efficiency filter is used to ensure that solid particle impurities in the exhaust gas are basically removed, and the filtering accuracy of the high-efficiency filter can reach 0.01-0.05 mm.

[0009] Preferably, in step S102, the concentration of concentrated sulfuric acid in the drying tower should be maintained at above 95%, and the calcium chloride particles in the drying box should be replaced regularly, and replaced when the moisture absorption capacity of the calcium chloride drops to 50% of its own weight.

[0010] Preferably, step S2 includes: S201. Absorbent selection: Select a suitable absorbent combination based on the analysis results of the fluoride components in the exhaust gas; S202. Mixing the absorbent with the fluorine-containing waste gas: passing the fluorine-containing waste gas into the absorption tower, and spraying the absorbent into the absorption tower in the form of atomization, so that the waste gas and the absorbent are fully in contact; S203. Monitor the flow rate and composition changes of exhaust gas: During the mixing process of fluorine-containing exhaust gas, install a flow meter and a gas composition analyzer on the exhaust gas pipeline to monitor the flow rate and composition changes of the exhaust gas in real time. The accuracy of the flow meter should be within ±1%, and the gas composition analyzer should accurately detect the content and type of fluoride in the exhaust gas; S204. Dynamically adjust the amount and concentration of absorbent: Automatically adjust the amount and concentration of absorbent according to the changes in exhaust gas flow and composition, and use the formula to calculate the specific amount. S205. Dynamically adjust temperature and pressure: The temperature and pressure in the absorption tower are monitored in real time through temperature sensors and pressure sensors. Heaters, coolers and pressure regulators are also provided. When the exhaust gas flow or composition changes, the heaters or coolers and pressure regulators are automatically adjusted to keep the temperature and pressure within the optimal range.

[0011] Preferably, in step S201, the specific method of selecting suitable additives is: When the waste gas mainly contains hydrogen fluoride gas, calcium hydroxide can be selected as the main absorbent, and a small amount of calcium oxide can be added as an auxiliary agent. Calcium hydroxide reacts with hydrogen fluoride to generate calcium fluoride and water, thereby effectively absorbing hydrogen fluoride in the waste gas. The addition of calcium oxide improves the absorption efficiency and promotes the reaction; when the waste gas contains complex fluoride forms, including fluorosilicic acid and sodium fluorosilicate, sodium hydroxide is selected as the main absorbent. Sodium hydroxide reacts with these complex fluorides to generate corresponding sodium salts and sodium fluoride. Sodium fluoride further reacts with concentrated sulfuric acid to generate anhydrous hydrogen fluoride.

[0012] Preferably, in step S202, the specific absorption tower parameters are that the temperature in the absorption tower should be controlled between 20-30°C, and the pressure is slightly higher than the atmospheric pressure, which can be set to 0.1-0.2 MPa.

[0013] Preferably, in step S203, the specific monitoring time is to record the exhaust gas flow and composition every 10-15 minutes.

[0014] Preferably, in step S204, the specific calculation formula is: Among them, the fluoride content in the exhaust gas is C (unit: mg / m³), the exhaust gas flow rate is Q (unit: m³ / h), the initial concentration of the absorbent is C0 (unit: mol / L), the theoretical amount of the absorbent is M (unit: mol / h), and 20 is the stoichiometric coefficient of the reaction between hydrogen fluoride and calcium hydroxide.

[0015] Preferably, in step S5, the parameters of the distillation tower are as follows: the temperature at the bottom of the distillation tower can be set between 40-50°C, the temperature at the top can be set between 20-30°C, and the pressure is controlled at 0.1-0.2 MPa. Through the distillation process, impurities and moisture are removed to obtain high-purity anhydrous hydrogen fluoride.

[0016] The present invention provides a production method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas. It has the following beneficial effects: 1. In the process of mixing the absorbent with the fluorine-containing waste gas, the present invention selects a suitable absorbent combination according to the waste gas composition. For example, when the waste gas mainly contains hydrogen fluoride gas, calcium hydroxide and calcium oxide are selected as absorbents, and when the waste gas contains complex fluoride forms, sodium hydroxide is selected as the absorbent. This method has strong pertinence, improves adaptability, and ensures the output of anhydrous hydrogen fluoride produced from fluorine-containing waste gas.

[0017] 2. The present invention ensures that the reaction is always carried out under the best conditions by monitoring the waste gas flow rate and composition changes in real time during the mixing process of the absorbent and the fluorine-containing waste gas, and dynamically adjusting the amount and concentration of the absorbent as well as the temperature and pressure, thereby further improving the output and quality of anhydrous hydrogen fluoride.

[0018] 3. The present invention can accurately calculate the dosage and concentration of the absorbent through a formula, accurately calculate the theoretical dosage of the absorbent, and maintain the ratio in the adjustment process. This precise calculation method improves the scientificity and accuracy of the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a flow chart of the method of the present invention.

[0020] Figure 2 This is the s1 flow chart of the present invention.

[0021] Figure 3 It is a schematic diagram of the process connection of the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example: Please see attached Figure 1 -Attached Figure 3 The embodiment of the present invention provides a method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas, comprising the following steps: S1. Waste gas quality detection: It is necessary to first filter and dry the waste gas, and then detect the fluorine-containing waste gas to determine the specific composition and content of fluoride in it, providing a basis for subsequent processes; S101. Exhaust gas filtration: Install a multi-stage filtration device, pass the fluorine-containing exhaust gas through the multi-stage filtration device, and set a coarse filter, a medium-efficiency filter, and a high-efficiency filter in the multi-stage filtration device. The coarse filter is used to filter out larger particles of impurities. The aperture of the coarse filter can be set to 1-2 mm. Then, a medium-efficiency filter is used to further remove tiny particles. The filtration accuracy of the medium-efficiency filter can be set between 0.1-0.5 mm. Finally, a high-efficiency filter is used to ensure that the solid particle impurities in the exhaust gas are basically removed. The filtration accuracy of the high-efficiency filter can reach 0.01-0.05 mm; S102. Waste gas drying: First, the waste gas is passed through a drying tower filled with concentrated sulfuric acid. The concentrated sulfuric acid reacts with the moisture in the waste gas to remove most of the moisture. The concentration of concentrated sulfuric acid in the drying tower should be maintained at more than 95%. Then, calcium chloride solid desiccant is used for deep drying. The waste gas dried with concentrated sulfuric acid is passed through a drying box filled with calcium chloride particles to further remove residual moisture. The calcium chloride particles should be replaced regularly and replaced when the moisture absorption capacity of calcium chloride drops to a certain level (when the moisture absorption reaches 50% of its own weight); S103. Waste gas detection: A gas composition analyzer can accurately detect the types and contents of various fluorides in the waste gas. Common fluorides include hydrogen fluoride, fluosilicic acid, sodium fluosilicate, etc. S2. Mixing the absorbent with the fluorine-containing waste gas: transmitting the detected waste gas to the absorption tower, so that the waste gas and the absorbent are mixed in the absorption tower, thereby producing anhydrous hydrogen fluoride; S201. Absorbent selection: According to the analysis results of the fluoride components in the exhaust gas, select the appropriate absorbent combination, specifically: When the waste gas mainly contains hydrogen fluoride gas, calcium hydroxide can be selected as the main absorbent, and a small amount of calcium oxide can be added as an auxiliary agent. Calcium hydroxide reacts with hydrogen fluoride to generate calcium fluoride and water, thereby effectively absorbing hydrogen fluoride in the waste gas. The addition of calcium oxide improves the absorption efficiency and promotes the reaction; When the waste gas contains complex fluoride forms, including fluorosilicic acid and sodium fluorosilicate, sodium hydroxide is selected as the main absorbent. Sodium hydroxide reacts with these complex fluorides to generate corresponding sodium salts and sodium fluoride. Sodium fluoride further reacts with concentrated sulfuric acid to generate anhydrous hydrogen fluoride.

[0024] reason: The main component of fluoride in the waste gas is hydrogen fluoride, and its content is relatively high. Choosing calcium hydroxide as the absorbent has the advantages of low cost and high reaction efficiency. When calcium hydroxide reacts with hydrogen fluoride, the calcium fluoride generated is a relatively stable compound that is easy to handle and recycle. At the same time, adding a small amount of calcium oxide further improves the absorption efficiency, because calcium oxide reacts with moisture in the waste gas to generate calcium hydroxide, thereby increasing the effective concentration of the absorbent; The waste gas contains complex fluoride forms, including fluorosilicic acid and sodium fluorosilicate. The reaction between these fluorides and calcium hydroxide is relatively complex and may generate byproducts that are difficult to handle. At this time, it is more appropriate to choose sodium hydroxide as the absorbent. Sodium hydroxide reacts with these complex fluorides to generate corresponding sodium salts and sodium fluoride. Sodium fluoride further reacts with concentrated sulfuric acid to generate anhydrous hydrogen fluoride. At the same time, sodium hydroxide has a strong alkalinity and reacts better with these complex fluorides to improve the absorption efficiency.

[0025] S202. Mixing the absorbent with the fluorine-containing waste gas: Pass the fluorine-containing waste gas into the absorption tower, and spray the absorbent into the absorption tower in the form of atomization, so that the waste gas and the absorbent are fully in contact, wherein the temperature in the absorption tower should be controlled between 20 - 30 ° C, and the pressure is slightly higher than the atmospheric pressure, which can be set to 0.1 - 0.2 MPa; S203. Monitor the flow rate and composition changes of exhaust gas: During the mixing process of fluorine-containing exhaust gas, install a flow meter and a gas composition analyzer on the exhaust gas pipeline to monitor the flow rate and composition changes of the exhaust gas in real time. The accuracy of the flow meter should be within ±1%. The gas composition analyzer can accurately detect the content and type of fluoride in the exhaust gas. The specific monitoring time is to record the exhaust gas flow rate and composition every 10-15 minutes; S204. Dynamically adjust the amount and concentration of absorbent: Automatically adjust the amount and concentration of absorbent according to the changes in exhaust gas flow and composition, specifically: It can be calculated by the following formula: in The fluoride content in the exhaust gas is C (unit: mg / m³), The exhaust gas flow is Q (unit: m³ / h), The initial concentration of the absorbent is C0 (unit: mol / L), Then the theoretical amount of absorbent M (unit: mol / h), 20 is the stoichiometric coefficient of the reaction between hydrogen fluoride and calcium hydroxide; S205. Dynamically adjust temperature and pressure: The temperature and pressure in the absorption tower are monitored in real time by temperature sensors and pressure sensors. A heater, a cooler, and a pressure regulator are provided. When the exhaust gas flow or composition changes, the heater or cooler and the pressure regulator are automatically adjusted to keep the temperature and pressure within the optimal range. Specifically: Assumption: When the exhaust gas flow rate increases, the temperature in the absorption tower may rise. At this time, the power of the cooler should be increased to keep the temperature between 20-30℃. When the fluoride content in the exhaust gas increases, the pressure in the absorption tower needs to be appropriately increased to promote the absorption reaction. The pressure adjustment range can be set according to the specific situation, generally fine-tuned between 0.1-0.2MPa; S3. Salt conversion: The fluoride salts obtained after absorption are discharged from the bottom of the absorption tower and sent to a reactor, in which concentrated sulfuric acid is added to react with the fluoride salts; S4. Exhaust gas cooling: The gas coming out of the reactor contains hydrogen fluoride and a small amount of impurity gas and moisture. First, the gas is cooled to 10-20℃ by a cooler to condense the hydrogen fluoride into liquid; S5. Purification by distillation tower: The condensed hydrogen fluoride liquid is sent to a distillation tower for distillation purification, wherein the temperature at the bottom of the distillation tower can be set between 40 - 50°C, the temperature at the top can be set between 20 - 30°C, and the pressure is controlled at 0.1 - 0.2 MPa. Through the distillation process, impurities and moisture are removed to obtain high-purity anhydrous hydrogen fluoride.

[0026] Comparative experiment: The differences in fluorine recovery rate, anhydrous hydrogen fluoride output, product purity and production efficiency between the production method of the present invention using fluorine-containing waste gas and the common method are compared to clarify the superiority of the present invention.

[0027] Experimental materials and equipment: Source of fluorine-containing waste gas: the same industrial fluorine-containing waste gas generation source.

[0028] The production system of the present invention comprises a multi-stage filtering device, a drying tower, a drying box, an absorption tower, a reactor, a cooler, a distillation tower, etc., which are arranged according to the parameter requirements of the present invention.

[0029] Common production systems: Traditional fluorine-containing waste gas treatment and anhydrous hydrogen fluoride production equipment use general filtering, drying, absorption, reaction and purification methods.

[0030] Experimental steps: 1. Preparation stage: The production system of the present invention and the common production system are started separately to ensure the normal operation of the equipment.

[0031] Conduct preliminary testing on fluorine-containing waste gas and record the initial composition and content of fluoride in the waste gas.

[0032] 2. Production process: Fluorine-containing waste gas with the same flow rate and composition is introduced into the production system of the present invention and the common production system respectively.

[0033] Operate according to the respective production process and record the key parameters of the production process, such as temperature, pressure, flow rate, absorbent dosage, etc.

[0034] 3. Detection stage: The anhydrous hydrogen fluoride products produced by the two systems are tested, including fluorine content determination, impurity analysis, product purity testing, etc.

[0035] Record the time consumed in the production process and calculate production efficiency.

[0036] Experimental results and analysis: 1. Fluorine recovery rate: The production system of the present invention achieves a fluorine recovery rate of 90% through accurate waste gas detection, targeted absorbent selection and dynamic adjustment of absorbent dosage and reaction conditions.

[0037] Common production system: fluorine recovery rate is 75%.

[0038] 2. Output of anhydrous hydrogen fluoride: The production system of the present invention: under optimized reaction conditions, the output of anhydrous hydrogen fluoride per unit time is 500 kg / hour.

[0039] Typical production system: Output is 400 kg / hour.

[0040] 3. Product purity: The production system of the present invention: after purification by a distillation tower, the purity of the product reaches 99.5%.

[0041] Common production system: product purity is 98%.

[0042] 4.Production efficiency: The production system of the present invention takes 8 hours from the introduction of waste gas to the production of high-purity anhydrous hydrogen fluoride.

[0043] Typical production system: 10 hours Experimental conclusion: Through comparative experiments, it can be clearly seen that the production method of the present invention for producing anhydrous hydrogen fluoride using fluorine-containing waste gas is superior to the common production system in terms of fluorine recovery rate, output, product purity and production efficiency, etc. It has significant excellence and practical application value.

[0044] Compare Projects Production system of the present invention Common production systems Fluorine recovery rate 90% 75% Anhydrous hydrogen fluoride production (kg / hour) 500 400 Product Purity 99.5% 98% Production efficiency (hours) 8 10 Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas, characterized in that: The following steps are involved: S1. Waste gas quality detection: It is necessary to first filter and dry the waste gas, and then detect the fluorine-containing waste gas to determine the specific composition and content of fluoride in it, providing a basis for subsequent processes; S2. Mixing the absorbent with the fluorine-containing waste gas: transmitting the detected waste gas to the absorption tower, so that the waste gas and the absorbent are mixed in the absorption tower, thereby producing anhydrous hydrogen fluoride; S3. Salt conversion: The fluoride salts obtained after absorption are discharged from the bottom of the absorption tower and sent to a reactor, in which concentrated sulfuric acid is added to react with the fluoride salts; S4. Exhaust gas cooling: The gas coming out of the reactor contains hydrogen fluoride and a small amount of impurity gas and moisture. First, the gas is cooled to 10-20℃ by a cooler to condense the hydrogen fluoride into liquid; S5. Distillation tower purification: The condensed hydrogen fluoride liquid is sent to a distillation tower for distillation purification.

2. The method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas according to claim 1, characterized in that: Step S1 includes: S101. Waste gas filtration: install a multi-stage filtration device, pass the fluorine-containing waste gas through the multi-stage filtration device, and set a coarse filter, a medium-efficiency filter, and a high-efficiency filter in the multi-stage filtration device; S102. Waste gas drying: First, the waste gas is passed through a drying tower filled with concentrated sulfuric acid, and the concentrated sulfuric acid reacts with the moisture in the waste gas to remove most of the moisture. Then, calcium chloride solid desiccant is used for deep drying. The waste gas dried with concentrated sulfuric acid is passed through a drying box filled with calcium chloride particles to further remove the residual moisture. S103. Waste gas detection: The gas composition analyzer can accurately detect the types and contents of various fluorides in the waste gas. Common fluorides include hydrogen fluoride, fluorosilicic acid, sodium fluorosilicate, etc.

3. The method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas according to claim 1, characterized in that: In step S101, larger particles of impurities are filtered out through a coarse filter, the pore size of the coarse filter can be set to 1-2 mm, and then a medium-efficiency filter is used to further remove tiny particles, and the filtering accuracy of the medium-efficiency filter can be set between 0.1-0.5 mm. Finally, a high-efficiency filter is used to ensure that solid particle impurities in the exhaust gas are basically removed, and the filtering accuracy of the high-efficiency filter can reach 0.01-0.05 mm.

4. The method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas according to claim 1, characterized in that: In step S102, the concentration of concentrated sulfuric acid in the drying tower should be maintained at above 95%, and the calcium chloride particles in the drying box should be replaced regularly, and replaced when the moisture absorption capacity of the calcium chloride drops to 50% of its own weight.

5. The method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas according to claim 1, characterized in that: Step S2 includes: S201. Absorbent selection: Select a suitable absorbent combination based on the analysis results of the fluoride components in the exhaust gas; S202. Mixing the absorbent with the fluorine-containing waste gas: passing the fluorine-containing waste gas into the absorption tower, and spraying the absorbent into the absorption tower in the form of atomization, so that the waste gas and the absorbent are fully in contact; S203. Monitor the flow rate and composition changes of exhaust gas: During the mixing process of fluorine-containing exhaust gas, install a flow meter and a gas composition analyzer on the exhaust gas pipeline to monitor the flow rate and composition changes of the exhaust gas in real time. The accuracy of the flow meter should be within ±1%, and the gas composition analyzer should accurately detect the content and type of fluoride in the exhaust gas; S204. Dynamically adjust the amount and concentration of absorbent: Automatically adjust the amount and concentration of absorbent according to the changes in exhaust gas flow and composition, and use the formula to calculate the specific amount. S205. Dynamically adjust temperature and pressure: The temperature and pressure in the absorption tower are monitored in real time through temperature sensors and pressure sensors. Heaters, coolers and pressure regulators are also provided. When the exhaust gas flow or composition changes, the heaters or coolers and pressure regulators are automatically adjusted to keep the temperature and pressure within the optimal range.

6. The method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas according to claim 1, characterized in that: In step S201, the specific method of selecting a suitable additive is: When the waste gas mainly contains hydrogen fluoride gas, calcium hydroxide can be selected as the main absorbent, and a small amount of calcium oxide can be added as an auxiliary agent. Calcium hydroxide reacts with hydrogen fluoride to generate calcium fluoride and water, thereby effectively absorbing hydrogen fluoride in the waste gas; The addition of calcium oxide improves the absorption efficiency and promotes the reaction. When the waste gas contains complex fluoride forms, including fluorosilicic acid and sodium fluorosilicate, sodium hydroxide is selected as the main absorbent. Sodium hydroxide reacts with these complex fluorides to generate corresponding sodium salts and sodium fluoride. Sodium fluoride further reacts with concentrated sulfuric acid to produce anhydrous hydrogen fluoride.

7. The method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas according to claim 1, characterized in that: In step S202, the specific absorption tower parameters are that the temperature in the absorption tower should be controlled between 20 - 30 ° C, and the pressure is slightly higher than the atmospheric pressure, which can be set to 0.1 - 0.2 MPa.

8. The method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas according to claim 1, characterized in that: In step S203, the specific monitoring time is to record the exhaust gas flow and composition every 10-15 minutes.

9. The method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas according to claim 1, characterized in that: In step S204, the specific calculation formula is: Among them, the fluoride content in the exhaust gas is C (unit: mg / m³), the exhaust gas flow rate is Q (unit: m³ / h), the initial concentration of the absorbent is C0 (unit: mol / L), the theoretical amount of the absorbent is M (unit: mol / h), and 20 is the stoichiometric coefficient of the reaction between hydrogen fluoride and calcium hydroxide.

10. The method for producing anhydrous hydrogen fluoride using fluorine-containing waste gas according to claim 1, characterized in that: In step S5, the parameters of the distillation tower are as follows: the temperature at the bottom of the distillation tower can be set between 40-50°C, the temperature at the top can be set between 20-30°C, and the pressure is controlled at 0.1-0.2 MPa. Through the distillation process, impurities and moisture are removed to obtain high-purity anhydrous hydrogen fluoride.

Images