In-situ recovery and reuse device for electronic-grade hydrofluoric acid

Abstract

The application discloses an electronic-grade hydrofluoric acid in-situ recycling device, and belongs to the field of wet electronic chemicals. The device comprises a reactor body, a cyclone liquid mixer and a circulating flow guide cylinder arranged in the reactor body; a reflux cavity is arranged at the lower end of the reactor body, a material returning sieve classifier is arranged at the upper portion of the reflux cavity, a circulating pump is arranged at the reflux cavity outside the reactor body, a first connecting pipe and a second connecting pipe are connected to the circulating pump, the first connecting pipe is communicated with the reflux cavity, and the second connecting pipe is communicated with the cyclone liquid mixer. The two materials are mixed through diagonal cyclone of the cyclone liquid mixer, and the problem of local supersaturation is avoided. The material returning sieve classifier is arranged at the bottom of the reactor body, the establishment of the material returning cone enables the crystal and the fluid mixture to be distributed in an umbrella shape at the inlet of the circulating fluidization zone, and the pores of the sieve plate can perform particle screening on the crystal seeds, so that the crystal seeds entering the circulating fluidization zone are homogenized in size.

Description

Technical Field

[0001] This invention relates to the field of wet electronic chemicals, and more specifically, to an in-situ recovery and reuse device for electronic-grade hydrofluoric acid. Background Technology

[0002] Electronic-grade hydrofluoric acid is a high-purity chemical reagent widely used in high-tech fields such as semiconductor manufacturing, photovoltaic industry, and LCD panels. However, due to its complex production process, high cost, and the presence of a certain concentration of hydrofluoric acid in the waste liquid after use, efficient recycling has become a key focus of the industry. Currently, traditional treatment methods mainly include neutralization and simple distillation. However, neutralization not only wastes resources but also generates a large amount of waste residue, increasing the difficulty of subsequent treatment; while existing distillation technology has limited ability to remove impurities and cannot meet the requirements of electronic-grade purity.

[0003] With the rapid development of the semiconductor industry, the demand for high-purity chemical reagents has been increasing year by year, accompanied by a significant increase in the emission of waste hydrofluoric acid. This not only wastes resources but also poses a potential threat to the environment.

[0004] Methods for treating waste hydrofluoric acid mainly include chemical precipitation, adsorption, and membrane separation. These methods can remove fluorides to some extent, but they typically suffer from high costs, limited efficiency, and secondary pollution. Crystallization fluidized bed technology, as an emerging treatment technology, has gradually attracted widespread attention. Crystallization fluidized bed technology generates crystallizing particles within a fluidized bed by controlling conditions such as temperature, concentration, and pH in the aqueous phase, thereby converting dissolved fluorides into solid crystals and achieving the removal of fluoride ions. However, crystallization fluidized bed technology also faces some challenges in its application. First, the size and distribution of crystallizing particles in the fluidized bed significantly affect the treatment effect, requiring precise control of operating conditions. Second, the supersaturation of fluorides and the crystallization rate need to be reasonably adjusted to avoid excessively rapid or incomplete crystallization. Furthermore, the design and operation of the crystallization fluidized bed require certain adjustments.

[0005] To improve the efficiency of crystallization recycling, many researchers have already conducted some research on fluidized bed crystallization technology.

[0006] Patent application CN111498967B discloses a crystallization fluidized bed for wastewater defluorination, phosphorus removal, and hardness removal. It uses a differential speed distributor with a double-layer perforated plate instead of a multi-hole distributor to create a capillary effect on the crystal particles, hindering their settling. However, this only increases the residence time of the seed crystals in the bed and cannot change or control the crystallization saturation and crystallization rate.

[0007] Patent application CN107915351B discloses a combined fluidized bed self-crystallization system for treating high-hardness wastewater. By adding reagents and utilizing the principle of chemical precipitation, calcium and magnesium ions are converted into calcium carbonate and magnesium hydroxide, which then undergo an induced crystallization reaction on seed crystals, depositing onto the seed crystals and ultimately being removed from the system via bottom sludge discharge. The supernatant is filtered through a ceramic membrane to separate fine particulate matter. While the supersaturation of crystallization can be controlled by adjusting the fluid flow rate, it cannot adjust the size and distribution of the crystallized particles, thus failing to control the purity of the crystallized product.

[0008] Patent application CN219823716U discloses a defluorination device that mixes the drug with waste liquid through pipelines and introduces it into a reaction tank. The waste liquid is gradually introduced into the system through alternating use of water supply pipes and distribution pipes, allowing powdered and granular defluorination agents to be transported into the mixing chamber. However, this method fails to distribute the crystallization during the process and cannot guarantee the crystallization rate.

[0009] Patent application CN117843108A discloses a crystallization fluidized bed device. The device is equipped with baffles to separate the internal structure. Crystals rise with the fluidized wastewater, pass through baffles, and are then recycled back to the influent side for cyclic crystallization. This preparation achieves cyclic fluidization of particles, but it is difficult to achieve particle homogenization and classification, making it difficult to provide uniform crystal nuclei for crystallization.

[0010] In summary, fluidized bed crystallization technology has made significant improvements in liquid distribution, crystal circulation, and operation control. However, problems still exist, such as crystal nucleus homogenization, supersaturation control (crystallization rate control), and crystal disintegration. There is still room for improvement in effectively increasing crystallization efficiency and purity. Therefore, we propose an in-situ recovery and reuse device for electronic-grade hydrofluoric acid. Summary of the Invention

[0011] The purpose of this invention is to provide an in-situ recovery and reuse device for electronic-grade hydrofluoric acid, so as to solve the problems mentioned in the background art.

[0012] To achieve the above objectives, the present invention provides the following technical solution:

[0013] An in-situ recovery and reuse device for electronic grade hydrofluoric acid includes a reactor body. Inside the reactor body, there is a cyclone mixer and a circulation guide tube. The cyclone mixer is located inside the circulation guide tube near the upper end. The circulation guide tube is located between the cyclone mixer and the inner wall of the reactor body.

[0014] A reflux chamber is provided at the lower end of the reactor body, and a return material screen is provided at the upper part of the reflux chamber. A circulation pump is provided on the outside of the reactor body at the reflux chamber. A first connecting pipe and a second connecting pipe are connected to the circulation pump. The first connecting pipe is connected to the reflux chamber, and the second connecting pipe is connected to the cyclone mixer.

[0015] The return material screener includes a return cone and a screening plate. The bottom surface of the return cone is connected to the top surface of the screening plate. The cone surface of the return cone faces upward, and the outer side of the screening plate is inclined.

[0016] Preferably, an inlet pipe A and a third connecting pipe are provided through both sides of the reactor body, the third connecting pipe is connected to the second connecting pipe, an inlet pipe B is provided through the top of the reactor body, and an outlet pipe is also provided on the side of the reactor body, the height of the outlet pipe in the vertical position is between the inlet pipe B and the third connecting pipe.

[0017] The lower end of the reactor body is located above the return material screen and has a crystal discharge port. The inner wall of the reactor body is coated with anti-scaling material, and the circulation guide tube adopts a tapered design.

[0018] Preferably, the cross-sectional area of ​​the vortex mixer is 4.5-6.5 times the sum of the cross-sectional areas of the inlet pipe A and the third connecting pipe.

[0019] Preferably, the cone angle of the return cone is 30°-60°, and the outer slope of the screening plate is set to 45°-90°;

[0020] The reactor body is located above the return material screener and is set as an inclined structure, with the crystal discharge port located at the inclined structure.

[0021] Preferably, the reactor body is located above the inclined structure as a crystallization chamber, and the cross-sectional area of ​​the reflux chamber is 30%-50% of the cross-sectional area of ​​the crystallization chamber.

[0022] Preferably, the cross-sectional area of ​​the circulation guide tube accounts for 50%-70% of the cross-sectional area of ​​the crystallization chamber;

[0023] The height of the circulating guide tube accounts for 30%-50% of the total height of the reactor body.

[0024] Preferably, the cyclone mixer includes a housing, with a first feed pipe and a second feed pipe respectively provided on both sides of the housing, and a third feed pipe provided on the top of the cyclone mixer. The first feed pipe is connected to the liquid inlet pipe A, the second feed pipe is connected to the third connecting pipe, and the third feed pipe is connected to the liquid inlet pipe B.

[0025] Preferably, the lower end of the third feed pipe extends into the housing, and the side wall of the third feed pipe inside the housing has multiple mounting ports. A mounting ring is rotatably connected to the mounting port, and multiple inclined blades are arranged in a ring shape on the inner side of the mounting ring.

[0026] Preferably, a spiral guide plate is provided inside the outer shell.

[0027] Preferably, an installation rod is provided below the return material screener, and an installation column is provided on the installation rod. A groove is provided on the bottom surface of the return material screener, and the installation column slides in the groove. A vibration mechanism is provided inside the installation column, and the vibration mechanism contacts the groove.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) The present invention uses a cyclone mixer to mix two materials diagonally, and the negative pressure zone in the middle continuously draws in the reactant, which helps to reduce the supersaturation of the reaction and avoid local supersaturation problems; under the condition of crystal presence, crystal nuclei expand and crystallize under low saturation conditions.

[0030] (2) This invention incorporates a return feed sieve at the bottom of the reactor body. The return feed cone ensures that the crystal and fluid mixture is distributed in an umbrella shape at the inlet of the circulating fluidized zone. Simultaneously, the pores in the sieve plate can sieve the seed crystals, resulting in uniform seed crystal size entering the circulating fluidized zone and a milder fluidized crystallization environment. This allows small crystal particles to continue circulating and crystallizing, achieving directional crystallization and expansion of uniform seed crystals within an effective height range. The uniform coarse seed crystals also provide a high upward flow rate for the circulation, allowing for the optimal stripping of calcium fluoride with low surface adhesion, thereby improving the crystal purity of calcium fluoride.

[0031] (3) The present invention sets up a circulating guide tube in the middle of the reactor body. The circulating guide tube separates the mixing and fluidized crystallization. At the same time, the difference in flow rate between the inner and outer barrels of the circulating guide tube realizes the controllability of crystallization, further increases the reaction between the seed crystal and the solution to be crystallized, and further provides the conditions for the seed crystal to grow. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0033] Figure 2 This is a cross-sectional view of the overall structure of the present invention;

[0034] Figure 3 This is a schematic diagram of the cyclone mixer structure of the present invention;

[0035] Figure 4 This is a schematic diagram of the return material screening device of the present invention;

[0036] Figure 5 This is a cross-sectional schematic diagram of the cyclone mixer of the present invention;

[0037] Figure 6 This is a cross-sectional schematic diagram of the return material screening device of the present invention.

[0038] The following are the labels in the diagram: 1. Reactor body; 101. Reflux chamber; 102. Crystallization chamber; 2. Swirl mixer; 201. Outer shell; 202. First feed pipe; 203. Second feed pipe; 204. Third feed pipe; 205. Mounting port; 206. Mounting ring; 207. Blade; 208. Spiral guide plate; 3. Circulation guide cylinder; 4. Return material screener; 401. Return material cone; 402. Screening plate; 403. Groove; 5. Circulation pump; 6. First connecting pipe; 7. Second connecting pipe; 8. Liquid inlet pipe A; 9. Third connecting pipe; 10. Liquid inlet pipe B; 11. Liquid outlet pipe; 12. Crystal discharge port; 13. Mounting rod; 14. Mounting column. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0040] Example 1:

[0041] Please see Figure 1-4 An in-situ recovery and reuse device for electronic-grade hydrofluoric acid includes a reactor body 1. The reactor body 1 is characterized by having a cyclone mixer 2 and a circulation guide cylinder 3 inside. The cyclone mixer 2 is located inside the circulation guide cylinder 3 near its upper end, and the circulation guide cylinder 3 is located between the cyclone mixer 2 and the inner wall of the reactor body 1. Through the cyclone mixer 2, the fluorine waste liquid and seed crystal particles are mixed in a cyclone manner. The feed material and seed crystals are fed in a bidirectional cyclone manner. The negative pressure generated at the center of the cyclone draws in the calcium solution to be reacted, achieving a gradual concentration mixing with the crystal nucleus as the core.

[0042] A reflux chamber 101 is provided at the lower end of the reactor body 1, and a return material screener 4 is provided at the upper part of the reflux chamber 101. A circulation pump 5 is provided on the outside of the reactor body 1 at the reflux chamber 101. A first connecting pipe 6 and a second connecting pipe 7 are connected to the circulation pump 5. The first connecting pipe 6 is connected to the reflux chamber 101. An inclined plate can be provided at the bottom of the reflux chamber 101. The top of the inclined plate is inclined to the side of the first connecting pipe 6 to facilitate the flow of crystals to the first connecting pipe 6. The second connecting pipe 7 is connected to the cyclone mixer 2. The return material screener 4 is provided directly below the cyclone mixer 2. Crystals smaller than the sieve hole size of the return material screener 4 fall into the reflux chamber 101 and enter the next cycle under the action of the circulation pump 5. After expanding, the seed crystals are returned to the fluidization zone.

[0043] Among them, such as Figure 2As shown, the arrows indicate the direction of liquid flow in the circulating fluidized zone; the inside of the cyclone mixer 2 is the liquid inlet mixing zone, used for preliminary mixing of fluorine-containing waste liquid and seed crystal particles; the seed crystal screening zone is composed of the return material screener 4, whose main function is to screen seed crystal particles of different sizes. The return material screener 4 adopts a porous screen structure, and the pore size is adjustable according to the working conditions.

[0044] The return material screener 4 includes a return cone 401 and a screening plate 402. The bottom surface of the return cone 401 is connected to the top surface of the screening plate 402. The cone surface of the return cone 401 is positioned upwards so that the crystal and fluid mixture is distributed in an umbrella shape at the inlet of the circulating fluidization zone. The outer surface of the screening plate 402 is inclined to facilitate crystal flow. The screening plate 402 adopts a porous screen structure, and the pore size can be adjusted according to the working conditions.

[0045] Fluorine-containing waste liquid is pumped into the cyclone mixer 2 through a pipeline and injected into the circulating guide tube 3 through a nozzle to form a swirling motion. Seed crystal particles are added through the feed port. The slight negative pressure generated by the swirling cavity draws in the reagent (such as calcium ion solution) or the reagent is pumped in through a pipeline to ensure that the waste liquid and the seed crystals are in full contact within the mixer.

[0046] In this application, inlet pipes A8 and third connecting pipes 9 are installed through both sides of the reactor body 1. Inlet pipe A8 is used to pump waste liquid into the cyclone mixer 2. The third connecting pipe 9 is connected to the second connecting pipe 7 to allow small-particle crystals to circulate into the cyclone mixer 2. Inlet pipe B10 is installed through the top of the reactor body 1 to feed waste liquid or reagents into the cyclone mixer 2. An outlet pipe 11 is also installed on the side of the reactor body 1 to discharge the waste liquid after the reaction. The vertical height of the outlet pipe 11 is between the inlet pipe B10 and the third connecting pipe 9. Both inlet pipes A8 and B10 are equipped with valves to control the flow rate of the liquid. Both inlet pipes A8 and B10 can be used for the addition of waste liquid or reagents.

[0047] The lower end of the reactor body 1 is located above the return screening device 4 and has a crystal discharge port 12 for discharging large crystal particles. The inner wall of the reactor body 1 is coated with an anti-scaling material to reduce the adhesion of calcium fluoride crystals and ensure long-term efficient operation of the equipment. The circulation guide tube 3 adopts a tapered design to enhance the uniformity of internal fluid flow and avoid insufficient local turbulence.

[0048] In this application, the cyclone mixer 2 includes a housing 201. A first feed pipe 202 and a second feed pipe 203 are respectively provided on both sides of the housing 201. A third feed pipe 204 is provided on the top of the cyclone mixer 2. The connection method of the pipes on the cyclone mixer 2 is as follows: the first feed pipe 202 is connected to the liquid inlet pipe A8, the second feed pipe 203 is connected to the third connecting pipe 9, the third feed pipe 204 is connected to the liquid inlet pipe B10, and the lower end of the third feed pipe 204 extends into the housing 201.

[0049] In this application, the cross-sectional area of ​​the cyclone mixer 2 is 4.5-6.5 times the sum of the cross-sectional areas of the inlet pipe A8 and the third connecting pipe 9.

[0050] In this application, the cone angle of the return cone 401 is 30°-60°, and the outer slope of the screening plate 402 is set to 45°-90°;

[0051] The reactor body 1 is located above the return screening device 4 and is set as an inclined structure. The crystal discharge port 12 is set at the inclined structure. The inclined structure facilitates the discharge of crystals.

[0052] In this application, the reactor body 1 is located above the inclined structure as the crystallization chamber 102, and the cross-sectional area of ​​the reflux chamber 101 is 30%-50% of the cross-sectional area of ​​the crystallization chamber 102.

[0053] In this application, the cross-sectional area of ​​the circulation guide tube 3 accounts for 50%-70% of the cross-sectional area of ​​the crystallization chamber 102; the height of the circulation guide tube 3 accounts for 30%-50% of the total height of the reactor body 1. The height difference between the feed inlet (liquid inlet pipe A8) and the discharge outlet (crystal discharge port 12) of the reactor body 1 is 3.6-4.8m.

[0054] Workflow:

[0055] Operation of cyclone mixer 2: After the fluoride-containing waste liquid enters cyclone mixer 2, it is thoroughly mixed with the seed crystals and reagents carried by the cyclone. By adjusting the cyclone intensity and reagent dosage, the supersaturation of the waste liquid is controlled within a set range, reducing seed crystal disintegration or fine particle formation caused by supersaturation. By adjusting the reagent dosage and cyclone speed, the supersaturation is reduced to a stable range, significantly reducing fine particle formation.

[0056] Crystallization reaction in the circulating fluidized zone: Waste liquid and seed crystals move downwards into the circulating fluidized zone. In this region, the seed crystals gradually grow and crystallize to form calcium fluoride, achieving particle homogenization through continuous fluidization. Furthermore, the crystallization process in the circulating fluidized zone is continuous, avoiding reduced crystallization efficiency caused by localized liquid stagnation or insufficient turbulence. The upward flow velocity in the reactor's circulating fluidized zone is 20 m / h-100 m / h.

[0057] Screening and circulation of return material screener 4: When liquid containing seed crystals of different sizes arrives at the return material screener, it is separated by the screen. Larger particles return to the circulating fluidized zone to continue the reaction, while smaller particles fall into the return chamber 101. The smaller particles in the return chamber 101 are then sent back into the cyclone mixer 2 by the circulation pump 5, thus achieving closed-loop operation.

[0058] Seed crystal growth and calcium fluoride purification: As the seed crystals grow, their particle size gradually increases, and the sieving efficiency gradually improves. Through multiple cycles, the seed crystals achieve calcium fluoride purification during repeated crystallization.

[0059] Example 2:

[0060] Please see Figure 5 , 6 The difference from Embodiment 1 is that the third feed pipe 204, located on the side wall inside the outer casing 201, has multiple mounting ports 205. A mounting ring 206 is rotatably connected to each mounting port 205. Multiple inclined blades 207 are arranged in a ring shape on the inner side of the mounting ring 206. By opening mounting ports 205 on the side wall of the third feed pipe 204, the reaction agent or reagent can be sprayed from the center outwards, facilitating thorough mixing of the reagent with the fluorine-containing waste liquid and crystals. Furthermore, the blades 207 rotate when the reagent liquid or waste liquid flows through them, generating thrust that further facilitates mixing of the reagent with the fluorine-containing waste liquid and crystals. Simultaneously, the rotating blades generate outward thrust, preventing liquid backflow into the third feed pipe 204.

[0061] Alternatively, an inclined cover can be installed on the outside of the installation port 205 to prevent waste liquid from entering the inside of the third feed pipe 204.

[0062] In one possible embodiment, a high-pressure nozzle is provided inside the mounting port 205, and the connecting pipe of the high-pressure nozzle is connected to the upper end of the third feed pipe 204. The high-pressure nozzle increases the force and speed of the agent spray.

[0063] In this embodiment, a spiral guide plate 208 is provided inside the outer shell 201. The spiral guide plate 208 guides the flow direction of the liquid and crystal, increases the flow path, and facilitates full contact between the waste liquid and the crystal.

[0064] In this embodiment, an installation rod 13 is provided below the return material screener 4, and an installation column 14 is provided on the installation rod 13. A groove 403 is provided on the bottom surface of the return material screener 4. The installation column 14 slides in the groove 403. A vibration mechanism is provided inside the installation column 14. The vibration mechanism contacts the groove 403. The vibration mechanism can be a vibration motor. By connecting the output shaft of the vibration motor to the inside of the groove 403, the vibration motor generates vibration force when it runs. Under the limiting action of the installation column 14, the vibration of the return material screener 4 moves back and forth in the vertical direction, thereby vibrating the crystals on the top of the screening plate 402, causing small crystals to fall down, and at the same time, causing the crystals located on the upper part of the screening plate 402 to turn over, which also facilitates the further crystallization of large crystals.

[0065] Experimental Example 1:

[0066] A photovoltaic cell factory produces 50m³ of electronic-grade hydrofluoric acid. 3 The concentration of F ions is not less than 5000 mg / L per hour, and the pH value is 0.1. Using the patented technology of this invention, it is converted into high-purity calcium fluoride as a raw material for the preparation of electronic-grade hydrofluoric acid, realizing the recycling of electronic-grade hydrofluoric acid. A cyclone mixer 2 with a cross-sectional area of ​​0.11 m² is installed inside the reactor body 1. 2 The reactor body 1 has a length of 0.5m, and the inlet reaction solution is 8% Ca(OH)2. The inlet pipe B has a diameter of DN25. The circulation guide tube 3 inside the reactor body 1 has an inner diameter of 1.2m and a length of 3.5m. The return material screen 4 at the bottom of the reactor body 1 has a return cone angle of 30°, and the screen plate 402 has an angle of 45° with the horizontal. The screen plate has a mesh size of 50. The screen section at the bottom of the reactor body 1 is connected to the seed crystal internal circulation pump 5, and its instantaneous velocity when entering the cyclone mixer 2 is 5.0m / s. The water outlet pipe at the top of the reactor normally produces water. After the reactor has been running for 4 hours, the discharge valve is opened to remove the crystals inside the reactor body 1 from the system, completing one working cycle. The results are shown in Table 1.

[0067] Experimental Example 2:

[0068] A semiconductor manufacturing plant produces 80m³ of electronic-grade hydrofluoric acid. 3 The concentration of F ions is not less than 4000 mg / L per hour, and the pH value is 0.1. The patented technology of this invention enables the recycling of electronic-grade hydrofluoric acid. A cyclone mixer 2 with a cross-sectional area of ​​0.18 m² is installed inside the reactor body 1. 2 The reactor body 1 has a length of 0.75m, and the inlet reaction solution is 8% Ca(OH)2. The inlet pipe B has a diameter of DN32. The circulating guide tube 3 inside the reactor body 1 has an inner diameter of 1.5m and a length of 4.8m. The return material screen 4 at the bottom of the reactor body 1 has a return cone angle of 45°, and the screen plate is at a 60° angle to the horizontal. The screen plate has a mesh size of 32. The screen section at the bottom of the reactor body 1 is connected to the seed crystal internal circulation pump 5, which enters the mixer at an instantaneous velocity of 5.0m / s. The water outlet pipe at the top of the reactor produces water normally. After the reactor has been running for 4.5 hours, the discharge valve is opened to remove the crystals inside the reactor body 1 from the system, completing one working cycle. The results are shown in Table 1.

[0069] Table 1: Comparison of experimental results of Experimental Example 1, Experimental Example 2, Comparative Example 1, and Comparative Example 2:

[0070] Experimental Example 1 50 Mixing / Remixing 1850 98.3％ Experimental Example 2 80 Mixing / Remixing 2030 98.7％ Comparative Example 1 50 Direct mixing 150 70％ Comparative Example 2 50 Water cap liquid 100 85％

[0071] In Table 1, Experimental Example 1, Experimental Example 2, Comparative Example 1, and Comparative Example 2 all used the same amount of reaction solution and hydrofluoric acid solution, and the reaction solution and hydrofluoric acid solution were added in a certain ratio. In Comparative Example 1, the total flow rate of electronic-grade hydrofluoric acid solution was 50 m³ / s.3 The concentration of F ions is not less than 5000 mg / L, the pH value is 0.1, and it is directly mixed with the reaction solution of 8% Ca(OH)2. Comparative Example 2 uses electronic-grade hydrofluoric acid solution with a total flow rate of 50 m³ / h. 3 The solution is mixed with 8% Ca(OH)2 in the reaction solution via a water cap distribution method. As can be seen from the data in Table 1, when the electronic-grade hydrofluoric acid solution is mixed with the reaction solution using the apparatus of this invention, the resulting crystals are larger and the calcium fluoride purity is also higher.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An in-situ recovery and reuse device for electronic-grade hydrofluoric acid, comprising a reactor body (1), characterized in that: The reactor body (1) is equipped with a swirl mixer (2) and a circulating guide tube (3). The swirl mixer (2) is located inside the circulating guide tube (3) near the upper end. The circulating guide tube (3) is located between the swirl mixer (2) and the inner wall of the reactor body (1). The circulating guide tube (3) adopts a tapered design. The reactor body (1) is provided with a reflux chamber (101) at the lower end, and a return material screener (4) is provided at the upper part of the reflux chamber (101). A circulation pump (5) is provided on the outside of the reactor body (1) at the reflux chamber (101). A first connecting pipe (6) and a second connecting pipe (7) are connected to the circulation pump (5). The first connecting pipe (6) is connected to the reflux chamber (101), and the second connecting pipe (7) is connected to the cyclone mixer (2). The return material screener (4) includes a return material cone (401) and a screening plate (402). The bottom surface of the return material cone (401) is connected to the top surface of the screening plate (402). The cone surface of the return material cone (401) is set facing upwards. The outer side surface of the screening plate (402) is an inclined surface. The reactor body (1) has an inlet pipe A (8) and a third connecting pipe (9) through its two sides. The reactor body (1) has an inlet pipe B (10) through its top. The cyclone mixer (2) includes a shell (201). The shell (201) has a first feed pipe (202) and a second feed pipe (203) on its two sides respectively. The cyclone mixer (2) has a third feed pipe (204) at its top. The first feed pipe (202) is connected to the inlet pipe A (8). The second feed pipe (203) is connected to the third connecting pipe (9). The third feed pipe (204) is connected to the inlet pipe B (10). The lower end of the third feed pipe (204) extends into the shell (201). The third feed pipe (204) has multiple mounting ports (205) on the side wall inside the outer shell (201). A mounting ring (206) is rotatably connected inside the mounting port (205). Multiple inclined blades (207) are arranged in a ring on the inner side of the mounting ring (206). The reactor body (1) is located above the inclined structure as a crystallization chamber (102), and the cross-sectional area of ​​the reflux chamber (101) is 30%-50% of the cross-sectional area of ​​the crystallization chamber (102); The cone angle of the return cone (401) is 30°-60°, and the outer slope of the screening plate (402) is set to 45°-90°; the reactor body (1) is set as an inclined structure above the return screening device (4), and the lower end of the reactor body (1) is set with a crystal discharge port (12) above the return screening device (4), and the crystal discharge port (12) is set at the inclined structure.

2. The in-situ recovery and reuse device for electronic-grade hydrofluoric acid according to claim 1, characterized in that: The inner wall of the reactor body (1) is coated with anti-scaling material. The third connecting pipe (9) is connected to the second connecting pipe (7). The side of the reactor body (1) is also provided with an outlet pipe (11). The height of the outlet pipe (11) in the vertical position is between the inlet pipe B (10) and the third connecting pipe (9).

3. The in-situ recovery and reuse device for electronic-grade hydrofluoric acid according to claim 2, characterized in that: The cross-sectional area of ​​the vortex mixer (2) is 4.5-6.5 times the sum of the cross-sectional areas of the inlet pipe A (8) and the third connecting pipe (9).

4. The in-situ recovery and reuse device for electronic-grade hydrofluoric acid according to claim 1, characterized in that: The cross-sectional area of ​​the circulating guide tube (3) accounts for 50%-70% of the cross-sectional area of ​​the crystallization cavity (102); The height of the circulating guide tube (3) accounts for 30%-50% of the total height of the reactor body (1).

5. The in-situ recovery and reuse device for electronic-grade hydrofluoric acid according to claim 1, characterized in that: The outer shell (201) is provided with a spiral guide plate (208).

6. The in-situ recovery and reuse device for electronic-grade hydrofluoric acid according to claim 1, characterized in that: An installation rod (13) is provided below the return material screener (4), and an installation column (14) is provided on the installation rod (13). A groove (403) is provided on the bottom surface of the return material screener (4). The installation column (14) slides in cooperation with the groove (403). A vibration mechanism is provided inside the installation column (14), and the vibration mechanism contacts the groove (403).

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