A recovery device and method for hydrofluoric acid waste liquid

Abstract

The application provides a hydrogen fluoride waste liquid recovery device and method, the recovery device comprises a hydrogen fluoride waste liquid storage unit, a micro-nano bubble generator and a separation unit, the separation unit is an inner-outer layer structure, the outside is a shell, the inside is a separation tank, a gap is left between the two, the upper part of the separation tank is open; the hydrogen fluoride waste liquid storage unit is divided into two branches and connected with the micro-nano bubble generator and the separation tank respectively, the micro-nano bubble generator is connected with the separation tank, and a condensing pipeline is arranged at the top of the shell. The micro-nano bubble generator is used as a functional equipment to generate micro-nano bubbles and use the micro-nano bubbles as a separation medium, then the structure of the separation unit is combined, the characteristics of the micro-nano bubbles are used to enrich the hydrogen fluoride, the bubbles are broken after reaching the surface of the solution, the hydrogen fluoride is evaporated, the hydrogen fluoride solution is obtained through condensation, the recovery rate of the hydrogen fluoride is high, the device structure is simple, the process operation is simple, no chemical reagent needs to be introduced, the follow-up impurity removal process is avoided, the treatment cost is low, and the application range is wide.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater recycling, and relates to a hydrogen fluoride waste liquid recovery device and method. BACKGROUND

[0002] With the rapid development of semiconductor technology, silicon and silicon compound raw materials are often used in related photovoltaic and liquid crystal industries. Hydrofluoric acid is often used in cleaning and etching processes, which generates a large amount of hydrogen fluoride waste liquid that is difficult to reuse directly. The main components of the hydrogen fluoride waste liquid are hydrofluoric acid, fluorosilicic acid and water, and the pH value is low. The hydrogen fluoride waste liquid has strong corrosive and oxidizing properties, and direct discharge will cause serious environmental pollution. Therefore, how to effectively treat the hydrogen fluoride waste liquid in the electronic industry is an important issue that needs to be solved urgently.

[0003] At present, the most commonly used method for treating hydrogen fluoride waste liquid is precipitation. By adding lime, calcium chloride and coagulant to the hydrogen fluoride waste liquid, the fluorine ions react with the calcium ions to form calcium fluoride precipitate, so as to remove the hydrogen fluoride. However, in this process, calcium ions need to be added, which increases the hardness of the water and makes the water quality worse. In addition, the hydrogen fluoride is converted into waste slag, which is difficult to regenerate and utilize, resulting in resource waste. In addition to the precipitation method, other methods that can be used include distillation and membrane separation, which usually require multiple unit operations to be combined to achieve the recycling of hydrogen fluoride.

[0004] CN 113754121A discloses a system and method for treating hydrogen fluoride-containing wastewater. The treatment method includes: first, solid-liquid separation treatment of the hydrogen fluoride-containing wastewater to obtain a liquid product and a first solid product; the liquid product is treated by membrane distillation to obtain an enrichment liquid; the enrichment liquid is then treated by ultrafiltration to obtain a fluorine ion-containing concentrated liquid and filtered water; and the two are treated by reverse osmosis to obtain hydrogen fluoride. This method uses a membrane assembly to distill and separate hydrogen fluoride, which requires a large amount of energy and has certain risks. In addition, the operation process is complex, the corrosion resistance of the equipment is high, and the economic efficiency is insufficient.

[0005] CN 113955720A discloses a method and device for preparing hydrogen fluoride from BOE waste liquid. The method includes: the BOE waste liquid reacts with alkali to generate a fluoride salt solution and ammonia water; ammonia gas is stripped at high temperature; the fluoride salt solution is decomposed into dilute hydrogen fluoride and dilute alkali by bipolar membrane electrodialysis; the former is distilled and concentrated into concentrated hydrogen fluoride and waste water; the latter is heated and concentrated into concentrated alkali and waste water; concentrated hydrogen fluoride reacts with concentrated sulfuric acid to obtain hydrogen fluoride gas and dilute sulfuric acid; and the dilute sulfuric acid is concentrated and recycled. This method is a process selected according to the composition of the BOE waste liquid. At this time, the fluorine exists in the form of fluoride salt, and ammonia gas is stripped. The overall process is relatively complex, and there are many heating and distillation operations, resulting in high energy consumption.

[0006] In summary, for the recovery of hydrofluoric acid in the waste hydrofluoric acid solution, a new process or operation is still needed to separate the hydrofluoric acid in the form of gas, without introducing other impurity ions, and to simplify the operation process, reduce energy consumption and cost. SUMMARY

[0007] In view of the problems in the prior art, the purpose of the present application is to provide a recovery device and method for waste hydrofluoric acid solution, which uses a micro-nano bubble generator as a functional device, generates micro-nano bubbles, uses them as a separation medium, and enriches hydrofluoric acid by using the characteristics of micro-nano bubbles. After leaving the solution, the bubbles burst and the hydrofluoric acid evaporates, and then it is separated from the waste liquid through condensation. The process is simple to operate and has low cost.

[0008] To achieve this purpose, the present application adopts the following technical solutions:

[0009] On the one hand, the present application provides a recovery device for waste hydrofluoric acid solution, which comprises a waste hydrofluoric acid solution storage unit, a micro-nano bubble generator and a separation unit. The separation unit has an inner and outer layer structure, with a shell on the outside and a separation tank on the inside. There is a gap between the shell and the separation tank, and the upper part of the separation tank is open. The outlet pipeline of the waste hydrofluoric acid solution storage unit is divided into two branches, one of which is connected to the micro-nano bubble generator, and the other is connected to the inlet of the separation tank in the separation unit. The outlet of the micro-nano bubble generator is connected to the inlet of the separation tank. The top of the shell is provided with a condensation pipeline, and the bottom of the shell is provided with a hydrofluoric acid solution outlet.

[0010] In the present application, for the recovery of waste hydrofluoric acid solution, a micro-nano bubble generator is used as a functional device to generate micro-nano bubbles, which are used as a separation medium. Due to the small size, large specific surface area, high surface potential difference and other characteristics of micro-nano bubbles, their structure is shown in Figure 1 The surface of micro-nano bubbles in water has a negative charge, while the combination of hydrogen and fluorine in hydrofluoric acid is stronger and does not completely ionize in water. Therefore, micro-nano bubbles can adsorb hydrogen ions and then adsorb weakly ionized fluorine ions to form a stable double electric layer. Micro-nano bubbles float and shrink in solution as the pressure increases, and the charged ions are quickly enriched to the surface of the solution. After the temperature rises, the bubbles burst, the hydrofluoric acid and water molecules evaporate, and the hydrofluoric acid is separated through condensation and reflux. To achieve this function, the separation unit is designed as an inner and outer layer structure, with the inner layer being a separation tank for enriching hydrofluoric acid with nano bubbles and leaving the solution, and then collecting through condensation and reflux of the outer shell. The device structure and process operation are simple, the separation efficiency is high, the cost is low, and the application range is wide.

[0011] The following is a preferred technical solution of the present application, but not as a limitation of the technical solutions provided by the present application. Through the following technical solutions, the technical purpose and beneficial effects of the present application can be better achieved and realized.

[0012] Preferably, the hydrogen fluoride waste liquid storage unit comprises a hydrogen fluoride storage tank.

[0013] Preferably, the micro-nano bubble generator is provided with an air inlet and a liquid inlet, and a gas delivery pump or a gas flow controller is arranged in front of the air inlet.

[0014] Preferably, the gas is dissolved in the hydrogen fluoride waste liquid entering the micro-nano bubble generator to form a saturated gas solution, and the micro-nano bubbles are formed by pressure reduction release.

[0015] In the present application, the micro-nano bubble generator comprises a bubble generator body, an air inlet and a liquid inlet, a pump, a certain vacuum degree is formed in front of the pump, the gas is sucked into the air inlet by negative pressure, and the saturated gas solution is formed by high-speed shearing of the pump impeller and pressure dissolving, and the micro-nano bubbles are formed by pressure reduction release after further stabilizing the gas in the expansion pipe.

[0016] Preferably, a temperature adjusting device is arranged above the liquid surface in the separation tank.

[0017] In the present application, the temperature adjusting device is arranged at the upper part of the separation tank, specifically above the liquid surface, and the temperature of the upper part of the waste liquid surface is controlled, and after the micro-nano bubbles reach the liquid surface and break, the heating can evaporate the hydrogen fluoride gas and water vapor, which can save energy compared with directly heating the liquid.

[0018] Preferably, the bottom of the separation tank is provided with a waste liquid outlet, which is directly connected to the outside of the separation unit.

[0019] Preferably, the separation tank is located in the middle part of the shell, and the diameter of the separation tank accounts for 50-80% of the diameter of the shell, for example, 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc., but is not limited to the listed values, and other values not listed in this range are also applicable.

[0020] Preferably, the top of the shell is provided with a gas outlet.

[0021] Preferably, the top of the shell is an arc surface structure with high middle position and low surrounding position.

[0022] Preferably, the condensing pipe is uniformly arranged at the top of the shell and located on the inner side of the shell in a coil type.

[0023] Preferably, the gap between the shell and the separation tank is a reflux channel, and the hydrogen fluoride vapor flows downward along the reflux channel after being condensed at the top of the shell.

[0024] In the present application, the structure design of the top of the shell can make the condensed hydrofluoric acid solution flow to the side, so that it can flow down along the inner wall of the shell, avoiding direct entry into the separation tank.

[0025] In the present application, the material of each structural unit in the recovery device, especially the structure directly contacted with the hydrofluoric acid waste liquid, is selected from materials resistant to hydrofluoric acid corrosion, such as polytetrafluoroethylene, polyethylene, polypropylene, and polytrifluorochloroethylene.

[0026] On the other hand, the present application provides a method for recovering hydrofluoric acid waste liquid using the above-mentioned recovery device, which comprises the following steps:

[0027] (1) passing the gas and the hydrofluoric acid waste liquid into the micro-nano bubble generator, dissolving the gas and releasing it under reduced pressure to obtain a micro-nano bubble solution;

[0028] (2) mixing the micro-nano bubble solution with another hydrofluoric acid waste liquid, enriching the micro-nano bubble with hydrofluoric acid, releasing the hydrofluoric acid vapor after the micro-nano bubble breaks away from the liquid surface, and obtaining the hydrofluoric acid solution after condensation to realize the recovery of the hydrofluoric acid.

[0029] As a preferred technical solution of the present application, the concentration of the hydrofluoric acid waste liquid in step (1) is 2-35wt%, such as 2wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt% or 35wt%, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0030] Preferably, the flow rate of the hydrofluoric acid waste liquid in step (1) is 1-30L / min, such as 1L / min, 5L / min, 10L / min, 15L / min, 20L / min, 25L / min or 30L / min, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0031] Preferably, the gas in step (1) includes air and / or nitrogen.

[0032] Preferably, the flow rate of the gas in step (1) is 5-20L / min, such as 5L / min, 7L / min, 10L / min, 12L / min, 15L / min, 18L / min or 20L / min, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0033] As a preferred technical solution of the present application, the gas in step (1) is sucked into the micro-nano bubble generator by a gas delivery pump.

[0034] Preferably, the gas pressurized dissolution in step (1) obtains a saturated dissolved gas liquid, and the dissolved gas is stabilized in the expansion pipe.

[0035] Preferably, the pressure of the gas pressurized dissolution is 0.1-3 MPa, for example, 0.1 MPa, 0.3 MPa, 0.6 MPa, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, or 3 MPa, but not limited to the listed values, and other values not listed in the range are also applicable.

[0036] Preferably, step (1) is performed by a impeller to reduce the pressure and disperse the gas into micro-nano bubbles.

[0037] Preferably, the size of the micro-nano bubbles in step (1) is 0.1-100 μm, for example, 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 20 μm, 40 μm, 60 μm, 80 μm, or 100 μm, but not limited to the listed values, and other values not listed in the range are also applicable.

[0038] In the present application, by controlling the dissolved gas pressure and the flow rate of the waste liquid, the size and density of the micro-nano bubbles can be controlled, the collision and adsorption between the bubbles and the liquid are increased, the hydrofluoric acid is enriched, and the temperature is adjusted by the temperature adjusting device, which helps the volatilization and separation of the hydrofluoric acid after the micro-nano bubbles leave the solution and break, and the hydrofluoric acid vapor is condensed and returned to obtain a hydrofluoric acid solution.

[0039] As a preferred technical solution of the present application, the volume ratio of the additional hydrofluoric acid waste liquid in step (2) to the hydrofluoric acid waste liquid in step (1) is 2:1-1:10, for example, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, 1:8, or 1:10, but not limited to the listed values, and other values not listed in the range are also applicable.

[0040] Preferably, the mixed waste liquid in step (2) is introduced into a separation tank.

[0041] Preferably, a temperature adjusting device is provided in the separation tank, and the temperature adjusting device is set to a temperature of 20-80℃, for example, 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, or 80℃, but not limited to the listed values, and other values not listed in the range are also applicable.

[0042] As a preferred technical solution of the present application, the micro-nano bubbles in step (2) are negatively charged, and continuously enrich the hydrofluoric acid in the waste liquid. During the rising of the micro-nano bubbles, the micro-nano bubbles shrink, and the temperature at the liquid surface increases to break the micro-nano bubbles, releasing the hydrofluoric acid vapor.

[0043] Preferably, the residence time of the mixed waste liquid in the separation tank in step (2) is 0.5-3h, such as 0.5h, 1h, 1.5h, 2h, 2.5h or 3h, but not limited to the listed values, other values not listed in the range are also applicable.

[0044] As a preferred technical solution of the present application, the hydrogen fluoride acid vapor moves upward during step (2) and condenses at the condensing pipeline at the top of the shell to form a hydrogen fluoride acid solution.

[0045] Preferably, the condensing medium in the condensing pipeline includes cold water or cold brine, and the temperature is 0-5℃, such as 0℃, 1℃, 2℃, 3℃, 4℃ or 5℃, but not limited to the listed values, other values not listed in the range are also applicable.

[0046] Preferably, the hydrogen fluoride acid solution flows downward along the reflux channel between the shell and the separation tank and flows out from the hydrogen fluoride acid solution outlet at the bottom.

[0047] Compared with the prior art, the present application has the following beneficial effects:

[0048] (1) The recovery device of the present application uses a micro-nano bubble generator as a functional device to generate micro-nano bubbles and use them as a separation medium, and combines the structure of the separation unit to enrich hydrogen fluoride acid by using the characteristics of micro-nano bubbles. After reaching the surface of the solution, the bubbles burst, the hydrogen fluoride acid evaporates, and then the hydrogen fluoride acid solution is obtained by condensation. The recovery rate of hydrogen fluoride acid can reach 50-80%;

[0049] (2) The device of the present application has a simple structure and easy process operation, and does not need to introduce impurities such as coagulants and chemical agents, avoiding the subsequent impurity removal process, reducing the processing cost, and having a wide application range. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 is a structural diagram of the micro-nano bubble of the present application described in the specification;

[0051] Figure 2 is a structural diagram of the hydrogen fluoride acid waste liquid recovery device provided in Example 1 of the present application;

[0052] Among them, 1-hydrogen fluoride acid waste liquid storage unit, 2-micro-nano bubble generator, 3-separation tank, 4-temperature adjusting device, 5-condensing pipeline, 6-reflux channel, 7-hydrogen fluoride acid solution outlet, 8-waste liquid outlet, 9-gas outlet. DETAILED DESCRIPTION

[0053] In order to better illustrate the present application, facilitate understanding of the technical solutions of the present application, the present application is further described in detail below. However, the following examples are only simple examples of the present application, and do not represent or limit the protection scope of the present application, and the protection scope of the present application is subject to the claims.

[0054] The following are typical but non-limiting examples of the present application:

[0055] Example 1:

[0056] This embodiment provides a hydrogen fluoride waste liquid recovery device, and a structure diagram of the recovery device is shown as Figure 2 The recovery device includes a hydrogen fluoride waste liquid storage unit 1, a micro-nano bubble generator 2, and a separation unit. The separation unit has an inner and outer layer structure, the outer side is a shell, and the inside is a separation tank 3. A gap is left between the shell and the separation tank 3. The upper part of the separation tank 3 is open. The outlet pipeline of the hydrogen fluoride waste liquid storage unit 1 is divided into two branches, one branch is connected with the micro-nano bubble generator 2, and the other branch is connected with the inlet of the separation tank 3 in the separation unit. The outlet of the micro-nano bubble generator 2 is connected with the inlet of the separation tank 3. The top of the shell is provided with a condensation pipeline 5. The bottom of the shell is provided with a hydrogen fluoride solution outlet 7.

[0057] The hydrogen fluoride waste liquid storage unit 1 is a hydrogen fluoride storage tank.

[0058] The micro-nano bubble generator 2 is provided with an air inlet and a liquid inlet. The air inlet is provided with a gas delivery pump in front of it.

[0059] The gas is dissolved in the hydrogen fluoride waste liquid entering the micro-nano bubble generator 2 to form a saturated gas solution, and the micro-nano bubbles are formed by releasing the pressure reduction of the impeller. The gas is air.

[0060] A temperature adjusting device 4 is arranged above the liquid surface in the separation tank 3.

[0061] The bottom of the separation tank 3 is provided with a waste liquid outlet 8, which is directly connected to the outside of the separation unit.

[0062] The separation tank 3 is located in the middle part of the shell, and the diameter of the separation tank 3 accounts for 70% of the diameter of the shell.

[0063] The top of the shell is provided with a gas outlet 9.

[0064] The top of the shell is an arc surface structure with a high middle position and a low surrounding position.

[0065] The condensation pipeline 5 is uniformly arranged at the top of the shell, located on the inside of the shell, and distributed in a coil type.

[0066] The gap between the shell and the separation tank is a reflux channel 6, through which the hydrogen fluoride vapor flows downward after condensing at the top of the shell.

[0067] Example 2:

[0068] This embodiment provides a recovery device for hydrogen fluoride waste liquid, which has the structure of the device in Example 1, with the only difference being that a gas flow controller is provided in front of the gas inlet of the micro-nano bubble generator 2, and the gas entering the gas inlet is nitrogen; the diameter of the separation tank 3 accounts for 60% of the diameter of the shell.

[0069] Example 3:

[0070] This embodiment provides a recovery method for hydrogen fluoride waste liquid, which is carried out using the device in Example 1, and includes the following steps:

[0071] (1) passing gas and hydrogen fluoride waste liquid into the micro-nano bubble generator, the concentration of the hydrogen fluoride waste liquid being 10wt%, the flow rate being 10L / min, the gas being air, the flow rate being 5L / min, the gas being sucked into the micro-nano bubble generator by a gas delivery pump, being pressurized and dissolved to obtain a saturated gas solution, the pressure during pressurized dissolution being 0.25MPa, and being depressurized to obtain a micro-nano bubble solution, the average size of the micro-nano bubbles being 85μm;

[0072] (2) mixing the micro-nano bubble solution with another hydrogen fluoride waste liquid, the volume ratio of the hydrogen fluoride waste liquid in this step to that in step (1) being 1:2, the mixed waste liquid entering the separation tank, the temperature of the temperature regulating device being set to 40℃, the micro-nano bubbles being negatively charged and continuously enriching hydrogen fluoride acid in the waste liquid, the micro-nano bubbles shrinking during the rising process, the temperature rising at the liquid surface to cause the micro-nano bubbles to break and release hydrogen fluoride vapor, the residence time of the waste liquid in the separation tank being 1h, the hydrogen fluoride vapor being condensed in the condensing pipeline at the top of the shell to form a hydrogen fluoride solution during the upward movement of the hydrogen fluoride vapor, the condensing medium in the condensing pipeline being cold water, the temperature of the condensing medium being 0℃, and the hydrogen fluoride solution flowing downward along the reflux channel between the shell and the separation tank and flowing out from the hydrogen fluoride solution outlet at the bottom.

[0073] In this embodiment, the above method is used to recover hydrogen fluoride from hydrogen fluoride waste liquid, and the recovery rate of hydrogen fluoride can reach 53%, the process operation is simple, and there is no subsequent impurity removal process.

[0074] Example 4:

[0075] This embodiment provides a recovery method for hydrogen fluoride waste liquid, which is carried out using the device in Example 1, and includes the following steps:

[0076] (1) gas and hydrofluoric acid waste liquid are introduced into a micro-nano bubble generator, the concentration of the hydrofluoric acid waste liquid is 15wt%, the flow rate of the introduction is 20L / min, the gas is air, the flow rate of the introduction is 10L / min, the gas is sucked into the micro-nano bubble generator by a gas delivery pump, pressurized dissolution is carried out to obtain a saturated dissolved gas liquid, the pressure during the pressurized dissolution is 0.7MPa, decompression is carried out to obtain a micro-nano bubble solution, and the average size of the micro-nano bubbles is 50μm;

[0077] (2) the micro-nano bubble solution is mixed with another introduced hydrofluoric acid waste liquid, the volume ratio of the hydrofluoric acid waste liquid introduced here to the hydrofluoric acid waste liquid in step (1) is 1:1, the mixed waste liquid enters a separation tank, the temperature adjusting device in the separation tank is set to 60℃, the micro-nano bubbles are negatively charged, the micro-nano bubbles shrink during the rising process, the temperature is increased at the liquid surface, the micro-nano bubbles are broken, and hydrogen fluoride vapor is released, the residence time of the waste liquid in the separation tank is 2h, the hydrogen fluoride vapor moves upward, is condensed in a condensing pipeline at the top of the shell, and forms a hydrofluoric acid solution, the condensing medium in the condensing pipeline is cold water, the temperature of the condensing medium is 1℃, and the hydrofluoric acid solution flows downward along a reflux channel between the shell and the separation tank, and flows out from a hydrofluoric acid solution outlet at the bottom.

[0078] In this embodiment, the above method is used for the recovery of hydrofluoric acid in the hydrofluoric acid waste liquid, and the recovery rate of the hydrofluoric acid can reach 65%, the process operation is simple, and there is no subsequent impurity removal process.

[0079] Example 5:

[0080] The embodiment provides a hydrofluoric acid waste liquid recovery method, and the method is carried out by using the device in Example 2 and includes the following steps.

[0081] (1) gas and hydrofluoric acid waste liquid are introduced into a micro-nano bubble generator, the concentration of the hydrofluoric acid waste liquid is 15wt%, the flow rate of the introduction is 20L / min, the gas is air, the flow rate of the introduction is 10L / min, the gas is sucked into the micro-nano bubble generator by a gas delivery pump, pressurized dissolution is carried out to obtain a saturated dissolved gas liquid, the pressure during the pressurized dissolution is 0.7MPa, decompression is carried out to obtain a micro-nano bubble solution, and the average size of the micro-nano bubbles is 50μm;

[0082] (2) the micro-nano bubble solution is mixed with another hydrogen fluoride waste liquid, the volume ratio of the hydrogen fluoride waste liquid in this step to the hydrogen fluoride waste liquid in step (1) is 1:6, the mixed waste liquid enters the separation tank, the temperature adjusting device in the separation tank is set to 80℃, the micro-nano bubble is negatively charged, the hydrogen fluoride in the waste liquid is continuously enriched, the micro-nano bubble shrinks in the rising process, the temperature is increased at the liquid surface, the micro-nano bubble is broken, hydrogen fluoride vapor is released, the residence time of the waste liquid in the separation tank is 1.5h, the hydrogen fluoride vapor moves upward and is condensed in the condensing pipeline at the top of the shell to form a hydrogen fluoride solution, the condensing medium in the condensing pipeline is cold brine, the temperature of the condensing medium is 5℃, and the hydrogen fluoride solution flows downward along the reflux channel between the shell and the separation tank and flows out from the hydrogen fluoride solution outlet at the bottom.

[0083] In this embodiment, the above method is used for recovering hydrogen fluoride from the hydrogen fluoride waste liquid, and the recovery rate of the hydrogen fluoride can reach 70%, the process operation is simple, and there is no subsequent impurity removal process.

[0084] Embodiment 6:

[0085] The embodiment provides a method for recovering hydrogen fluoride waste liquid, and the method is performed by using the device in embodiment 2 and includes the following steps.

[0086] (1) gas and hydrogen fluoride waste liquid are introduced into a micro-nano bubble generator, the concentration of the hydrogen fluoride waste liquid is 20wt%, the flow rate of the hydrogen fluoride waste liquid is 30L / min, the gas is nitrogen, the flow rate of the nitrogen is 20L / min, the gas is sucked into the micro-nano bubble generator by a gas delivery pump, is dissolved under pressure to obtain a saturated gas solution, is released under reduced pressure to obtain a micro-nano bubble solution, and the average size of the micro-nano bubble is 10μm;

[0087] (2) the micro-nano bubble solution is mixed with another hydrogen fluoride waste liquid, the volume ratio of the hydrogen fluoride waste liquid in this step to the hydrogen fluoride waste liquid in step (1) is 1:4, the mixed waste liquid enters the separation tank, the temperature adjusting device in the separation tank is set to 70℃, the micro-nano bubble is negatively charged, the hydrogen fluoride in the waste liquid is continuously enriched, the micro-nano bubble shrinks in the rising process, the temperature is increased at the liquid surface, the micro-nano bubble is broken, hydrogen fluoride vapor is released, the residence time of the waste liquid in the separation tank is 3h, the hydrogen fluoride vapor moves upward and is condensed in the condensing pipeline at the top of the shell to form a hydrogen fluoride solution, the condensing medium in the condensing pipeline is cold water, the temperature of the condensing medium is 3℃, and the hydrogen fluoride solution flows downward along the reflux channel between the shell and the separation tank and flows out from the hydrogen fluoride solution outlet at the bottom.

[0088] In this embodiment, the above method is used for recovering hydrogen fluoride from the hydrogen fluoride waste liquid, and the recovery rate of the hydrogen fluoride can reach 78%, the process operation is simple, and there is no subsequent impurity removal process.

[0089] Comparative Example 1:

[0090] The present comparative example provides a recovery device and method for hydrofluoric acid waste liquid, the structure of the recovery device refers to the device in Example 1, the only difference is that it does not include the micro-nano bubble generator 2.

[0091] The method refers to the method in Example 3, the only difference is that it does not include the generation of micro-nano bubbles in step (1), but directly passes the hydrofluoric acid waste liquid into the separation tank.

[0092] In the present comparative example, since the micro-nano bubble generator is not set, there are no micro-nano bubbles as separation medium, the hydrofluoric acid waste liquid is heated for separation of hydrofluoric acid, and the recovery effect of hydrofluoric acid is very poor, with a recovery rate of only about 0.5%.

[0093] Comparative Example 2:

[0094] The present comparative example provides a recovery device and method for hydrofluoric acid waste liquid, the structure of the recovery device refers to the device in Example 2, the only difference is that it does not include the micro-nano bubble generator 2.

[0095] The method refers to the method in Example 5, the only difference is that it does not include the generation of micro-nano bubbles in step (1), but directly passes the hydrofluoric acid waste liquid into the separation tank.

[0096] In the present comparative example, since the micro-nano bubble generator is not set, there are no micro-nano bubbles as separation medium, the hydrofluoric acid waste liquid is heated for separation of hydrofluoric acid, and the recovery effect of hydrofluoric acid is very poor, with a recovery rate of only about 0.5%.

[0097] From the above examples and comparative examples, it can be seen that the recovery device of the present application uses a micro-nano bubble generator as a functional device to generate micro-nano bubbles and use them as separation medium, and then uses the characteristics of micro-nano bubbles to enrich hydrofluoric acid, the bubbles burst after reaching the surface of the solution, the hydrofluoric acid evaporates, and then the hydrofluoric acid solution is obtained by condensation, the recovery rate of hydrofluoric acid can reach 50-80%; the device structure is simple, the process operation is simple, no impurities such as coagulants and chemical agents need to be introduced, the subsequent impurity removal process is avoided, the processing cost is low, and the application range is wide.

[0098] The applicant declares that the present application is illustrated by the above examples to explain the detailed device and method of the present application, but the present application is not limited to the above detailed device and method, i.e. it does not mean that the present application must rely on the above detailed device and method to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the device of the present application, addition of auxiliary devices, selection of specific methods, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. An apparatus for recovering hydrofluoric acid waste solution, characterized by comprising: The recovery device comprises a hydrofluoric acid waste liquid storage unit, a micro-nano bubble generator and a separation unit, the separation unit has an inner-outer layer structure, the outer layer is a shell and the inner layer is a separation tank, a gap is left between the shell and the separation tank, the upper part of the separation tank is open, the outlet pipeline of the hydrofluoric acid waste liquid storage unit is divided into two branches, one branch is connected with the micro-nano bubble generator and the other branch is connected with the inlet of the separation tank, the outlet of the micro-nano bubble generator is connected with the inlet of the separation tank, a condensing pipeline is arranged on the top of the shell, and a hydrofluoric acid solution outlet is arranged on the bottom of the shell. A temperature adjusting device is arranged above the liquid surface in the separation tank.

2. The apparatus for recovering the spent hydrofluoric acid solution according to claim 1, wherein The hydrofluoric acid waste liquid storage unit comprises a hydrofluoric acid storage tank.

3. The apparatus for recovering the spent hydrofluoric acid solution according to claim 1, wherein An air inlet and a liquid inlet are arranged on the micro-nano bubble generator, and a gas delivery pump or a gas flow controller is arranged in front of the air inlet.

4. The apparatus for recovering the spent hydrofluoric acid solution according to claim 3, wherein The gas is dissolved in the hydrofluoric acid waste liquid entering the micro-nano bubble generator to form saturated gas solution, and the micro-nano bubbles are formed by releasing the gas in the expansion pipe through the impeller.

5. The apparatus for recovering the spent hydrofluoric acid solution according to claim 1, wherein An exhaust liquid outlet is arranged on the bottom of the separation tank and is directly connected to the outside of the separation unit.

6. The apparatus for recovering the spent hydrofluoric acid solution according to claim 5, wherein The separation tank is located in the middle of the shell, and the diameter of the separation tank accounts for 50-80% of the diameter of the shell.

7. The apparatus for recovering the spent hydrofluoric acid solution according to claim 1, wherein A gas outlet is arranged on the top of the shell.

8. The apparatus for recovering the spent hydrofluoric acid solution according to claim 1, wherein The top of the shell has an arc surface structure with a high middle position and a low surrounding position.

9. The apparatus for recovering the spent hydrofluoric acid solution according to claim 1, wherein The condensing pipeline is uniformly arranged on the top of the shell and is located on the inner side of the shell in a coil type.

10. The apparatus for recovering the spent hydrofluoric acid solution according to claim 1, wherein The gap between the shell and the separation tank is a reflux channel, and the hydrofluoric acid vapor flows downward along the reflux channel after being condensed on the top of the shell.

11. A method for recovering hydrofluoric acid waste solution using the recovery apparatus according to any one of claims 1 to 10, characterized by, The method comprises the following steps: (1) passing the gas and the hydrofluoric acid waste liquid into the micro-nano bubble generator, dissolving the gas and releasing it by reducing the pressure to obtain a micro-nano bubble solution; (2) mixing the micro-nano bubble solution with another hydrofluoric acid waste liquid, enriching the hydrofluoric acid with the micro-nano bubbles, releasing the hydrofluoric acid vapor after the micro-nano bubbles break away from the liquid surface, and obtaining a hydrofluoric acid solution after condensation to realize the recovery of the hydrofluoric acid.

12. The method of recovering hydrofluoric acid waste according to claim 11, wherein In step (1), the concentration of the hydrofluoric acid waste liquid is 2-35wt%.

13. The method of recovering hydrofluoric acid waste according to claim 11, wherein In step (1), the flow rate of the hydrofluoric acid waste liquid is 1-30L / min.

14. The method of recovering hydrofluoric acid waste according to claim 11, wherein In step (1), the gas comprises air and / or nitrogen.

15. The method of recovering hydrofluoric acid waste according to claim 11, wherein In step (1), the flow rate of the gas is 5-20L / min.

16. The method of recovering hydrofluoric acid waste according to claim 11, wherein In step (1), the gas is sucked into the micro-nano bubble generator by the gas delivery pump.

17. The method of recovering hydrofluoric acid waste according to claim 11, wherein In step (1), the gas is dissolved by pressurization to obtain saturated gas solution, and the gas is stabilized in the expansion pipe.

18. The method of recovering hydrofluoric acid waste according to claim 17, wherein, The pressure during the pressurized dissolution of the gas is 0.1-3MPa.

19. The method of recovering hydrofluoric acid waste according to claim 11, wherein In step (1), the gas is dispersed into micro-nano bubbles by reducing the pressure through the impeller.

20. The method of recovering hydrofluoric acid waste according to claim 19, wherein, In step (1), the size of the micro-nano bubbles is 0.1-100μm.

21. The method of recovering hydrofluoric acid waste according to claim 11, wherein In step (2), the volume ratio of the other hydrofluoric acid waste liquid to the hydrofluoric acid waste liquid in step (1) is 2:1-1:

10.

22. The method of recovering hydrofluoric acid waste according to claim 11, wherein In step (2), the mixed waste liquid is passed into the separation tank.

23. The method of recovering hydrofluoric acid waste according to claim 11, wherein A temperature adjusting device is arranged in the separation tank, and the temperature adjusting device is set to a temperature of 20-80℃.

24. The method of recovering hydrofluoric acid waste according to claim 11, wherein, The micro-nano bubbles in step (2) are negatively charged, and continuously enrich hydrofluoric acid in the waste liquid. The micro-nano bubbles shrink during the rising process, and the temperature at the liquid surface is increased to break the bubbles to release the hydrofluoric acid vapor.

25. The method of recovering hydrofluoric acid waste according to claim 11, wherein, The residence time of the mixed waste liquid in the separation tank in step (2) is 0.5-3 h.

26. The method of recovering hydrofluoric acid waste according to claim 11, wherein The hydrofluoric acid vapor moves upward in step (2), and is condensed at the condensing pipeline at the top of the shell to form a hydrofluoric acid solution.

27. The method of recovering hydrofluoric acid waste according to claim 26, wherein The condensing medium in the condensing pipeline includes cold water or cold brine, and the temperature is 0-5 ℃.

28. The method of recovering hydrofluoric acid waste according to claim 26, wherein The hydrofluoric acid solution flows downward along the reflux channel between the shell and the separation tank, and flows out from the hydrofluoric acid solution outlet at the bottom.

Images