Electronic-grade hydrofluoric acid in-situ recycling device

Abstract

The invention 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, and a rotational flow liquid mixer and a circulating guide cylinder are arranged in the reactor body; a backflow cavity is formed in the lower end of the reactor body, a returned material screening device is arranged on the upper portion of the backflow cavity, a circulating pump is arranged on the outer side of the reactor body and located at the backflow cavity, a first connecting pipe and a second connecting pipe are connected to the circulating pump, the first connecting pipe is communicated with the backflow cavity, and the second connecting pipe is communicated with the rotational flow liquid mixer. Two materials are mixed in a diagonal rotational flow mode through the rotational flow liquid mixer, the problem of local supersaturation is avoided, the returned material screener is arranged at the bottom of the reactor body, crystals and fluid mixed liquid are distributed in an umbrella shape at an inlet of a circulating fluidization area due to the arrangement of a returned material cone, and the crystallization effect is improved. And meanwhile, pores formed in the screening plate can be used for carrying out particle screening on the seed crystals, so that the sizes of the seed crystals entering the circulating fluidization area are homogenized.

Description

Technical Field

[0001] The invention relates to the field of wet electronic chemicals, and more specifically to an in-situ recycling device for electronic-grade hydrofluoric acid. Background Art

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

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

[0004] The treatment methods for waste hydrofluoric acid mainly include chemical precipitation, adsorption and membrane separation. These methods can remove fluoride in the waste to a certain extent, but they usually have problems such as high treatment cost, limited treatment efficiency and secondary pollution. Crystallization fluidized bed technology has gradually attracted widespread attention as an emerging treatment technology. Crystallization fluidized bed technology generates crystalline particles in the fluidized bed by controlling the temperature, concentration and pH conditions in the water phase, thereby converting the fluoride dissolved in the water into solid crystals to achieve the purpose of removing fluoride ions. However, crystallization fluidized bed technology also faces some challenges in its application. First, the size and distribution of the crystalline particles in the fluidized bed have a great influence on the treatment effect, and the operating conditions need to be precisely controlled. Secondly, the supersaturation and crystallization rate of fluoride need to be reasonably adjusted to avoid too fast or incomplete crystallization during the crystallization process. In addition, the design and operation of the crystallization fluidized bed require certain adjustments.

[0005] In order to improve the efficient recycling of crystals, many researchers have conducted partial research on fluidized crystallization technology.

[0006] Patent application CN111498967B discloses a crystallization fluidized bed for wastewater defluorination, dephosphorization and hardness removal, which uses a differential water distributor with double-layer perforated plates instead of a porous water distributor to form a suction effect on crystal particles and block their sinking. However, it only increases the residence time of seed particles in the bed, and cannot change and 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 applying the principle of chemical precipitation, calcium and magnesium ions are converted into calcium carbonate and magnesium hydroxide, and an induced crystallization reaction occurs on the seed crystals, thereby depositing on the seed crystals and finally being removed from the system by bottom mud discharge. The supernatant is filtered and separated from fine particles through a ceramic membrane. The supersaturation of crystallization is controlled by adjusting the flow rate of fluid movement, but the size and distribution of the crystal particles cannot be adjusted, and the purity of the crystallized product cannot be controlled.

[0008] Patent application CN219823716U discloses a defluorination device, which mixes drugs with waste liquid through pipeline mixing and enters the reaction barrel. By alternately using a water pipe and a distribution pipe, the waste liquid gradually enters the system, and the powdered defluorination agent and the granular defluorination agent are transmitted to the inside of the mixing box. However, the crystal distribution in the process cannot be distributed, and the crystallization rate of the crystal cannot be guaranteed.

[0009] Patent application CN117843108A discloses a crystallization fluidized bed device, in which a partition is set to separate the interior of the device, and the crystals rise with the sewage fluidization, and after passing through the baffle, they are circulated back to the water inlet side for cyclic crystallization. This preparation realizes the cyclic fluidization of particles, but it is difficult to achieve homogenization and classification of particles, and it is difficult to provide homogenized crystal nuclei for crystallization.

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

[0011] The object of the present invention is to provide an in-situ recovery and reuse device for electronic-grade hydrofluoric acid to solve the problems raised in the above-mentioned background technology.

[0012] To achieve the above object, the present invention provides the following technical solutions:

[0013] An electronic-grade hydrofluoric acid in-situ recycling and reuse device comprises a reactor body, wherein a cyclone mixer and a circulation guide tube are arranged inside the reactor body, wherein the cyclone mixer is located inside the circulation guide tube near the upper end, and 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, a return material screener is provided at the upper part of the reflux chamber, a circulation pump is provided at the reflux chamber outside the reactor body, 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 comprises a return material cone and a screening plate. The bottom surface of the return material cone is connected to the top surface of the screening plate. The conical surface of the return material cone is arranged upward, and the outer side surface of the screening plate is an inclined surface.

[0016] Preferably, a liquid inlet pipe A and a third connecting pipe are provided through the two sides of the reactor body, the third connecting pipe is connected to the second connecting pipe, a liquid inlet pipe B is provided through the top of the reactor body, and a liquid outlet pipe is further provided on the side of the reactor body, and the height of the liquid outlet pipe in the vertical position is located between the liquid inlet pipe B and the third connecting pipe;

[0017] A crystal discharge port is arranged at the lower end of the reactor body above the return material screener, 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 cyclone mixer is 4.5-6.5 times the sum of the cross-sectional areas of the liquid inlet pipe A and the third connecting pipe.

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

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

[0021] Preferably, the reactor body located above the inclined structure is 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 circulation guide tube accounts for 30%-50% of the total height of the reactor body.

[0024] Preferably, the cyclone mixer includes an outer shell, and a first feed pipe and a second feed pipe are respectively arranged on both sides of the outer shell, and a third feed pipe is arranged 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 outer shell, and a plurality of mounting openings are provided on the side wall of the third feed pipe located in the outer shell. A mounting ring is rotatably connected in the mounting opening, and a plurality of inclined blades are arranged in a ring shape on the inner side of the mounting ring.

[0026] Preferably, a spiral guide plate is arranged inside the housing.

[0027] Preferably, a mounting rod is provided below the return material screener, a mounting column is provided on the mounting rod, a groove is provided on the bottom surface of the return material screener, the mounting column and the groove are slidably matched, a vibration mechanism is provided in the mounting column, and the vibration mechanism is in contact with the groove.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The present invention uses a cyclone mixer to mix two materials in a diagonal cyclone, and the negative pressure zone in the middle continuously absorbs the reactant, which is beneficial to reducing the supersaturation of the reaction and avoiding the problem of local supersaturation; in the presence of crystals, crystal nucleus expansion and crystallization are carried out under low saturation conditions.

[0030] (2) The present invention sets a return material screener at the bottom of the reactor body. The setting of the return material cone makes the crystal and fluid mixture distributed in an umbrella shape at the entrance of the circulating fluidized zone. At the same time, the pores set in the screening plate can screen the crystal seeds, so that the size of the crystal seeds entering the circulating fluidized zone is uniform, and the fluidized crystallization environment is milder. The small particle crystals continue to circulate and crystallize, and the directional crystallization and expansion of uniform crystal seeds are completed within the effective height range. The uniform coarse crystal seeds also provide a high rising flow rate for the circulation, and the calcium fluoride with a low surface adhesion rate is preferably peeled off, thereby improving the crystal purity of calcium fluoride.

[0031] (3) The present invention sets up a circulation guide tube in the middle of the reactor body, which separates mixing from fluidized crystallization. At the same time, the difference in flow rate between the inner and outer barrels of the circulation guide tube realizes controllable crystallization, further increases the reaction between the seed crystal and the solution to be crystallized, and further provides conditions for the seed crystal to crystallize. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0035] Figure 4 It is a schematic diagram of the structure of the return material screener of the present invention;

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

[0037] Figure 6 It is a cross-sectional schematic diagram of the return material screener of the present invention.

[0038] Explanation of the numbers in the figure: 1. Reactor body; 101. Reflux chamber; 102. Crystallization chamber; 2. Cyclone mixer; 201. 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 tube; 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 DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0040] Embodiment 1:

[0041] See also Figure 1-4 An electronic-grade hydrofluoric acid in-situ recovery and reuse device comprises a reactor body 1, characterized in that: a cyclone mixer 2 and a circulation guide tube 3 are arranged inside the reactor body 1, the cyclone mixer 2 is located on the inner side of the circulation guide tube 3 near the upper end, and the circulation guide tube 3 is located between the cyclone mixer 2 and the inner wall of the reactor body 1; through the arrangement of the cyclone mixer 2, the fluorine waste liquid and the seed particles are mixed in a cyclone manner, the feed and the seed crystal are fed in a bidirectional cyclone manner, and the negative pressure generated at the cyclone center sucks in the calcium solution to be reacted, thereby realizing concentration gradient 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 at the reflux chamber 101 on the outer side of the reactor body 1, and 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 an inclined plate can be provided at the bottom of the reflux chamber 101. The top surface of the inclined plate is inclined toward the first connecting pipe 6 to facilitate the crystals to flow toward the first connecting pipe 6. The second connecting pipe 7 is connected to the cyclone mixer 2; a return material screener 4 is provided directly below the cyclone mixer 2, and crystals smaller than the particle size of the sieving hole 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 swelling, the seed crystals are returned to the fluidized zone.

[0043] Among them Figure 2As shown in the figure, the direction indicated by the arrow is the direction of liquid flow in the circulating fluidized zone; the interior of the cyclone mixer 2 is the liquid inlet mixing zone, which is used for preliminary mixing of the fluorine-containing waste liquid and the seed particles; the seed screening zone is composed of a return screener 4, and its main function is to screen seed particles of different particle sizes. The return screener 4 adopts a porous screen structure, and the pore size is adjusted according to the working conditions.

[0044] The return material screener 4 includes a return material cone 401 and a screen plate 402. The bottom surface of the return material cone 401 is connected to the top surface of the screen plate 402. The conical surface of the return material cone 401 is arranged upward so that the crystal and the fluid mixture are distributed in an umbrella shape at the entrance of the circulating fluidization zone. The outer side surface of the screen plate 402 is an inclined surface to facilitate the flow of crystals. The screen plate 402 adopts a porous screen structure, and the pore size is 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 circulation guide tube 3 through a nozzle to form a cyclone motion. Seed particles are added through the feed port, and the slight negative pressure generated by the cyclone cavity sucks the reagent (such as calcium ion solution) or pumps the reagent into the mixer through a pipeline to ensure that the waste liquid and the seed crystal are fully in contact in the mixer.

[0046] In the present application, the two sides of the reactor body 1 are penetrated by a liquid inlet pipe A8 and a third connecting pipe 9, the liquid 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, and is used to circulate small particle crystals into the cyclone mixer 2, the top of the reactor body 1 is penetrated by a liquid inlet pipe B10, which is used to send waste liquid or medicine into the cyclone mixer 2, and the side of the reactor body 1 is also provided with a liquid outlet pipe 11, which is used to discharge the waste liquid after the reaction, wherein the height of the liquid outlet pipe 11 in the vertical position is located between the liquid inlet pipe B10 and the third connecting pipe 9; wherein the liquid inlet pipe A8 and the liquid inlet pipe B10 are both provided with valve bodies, which are used to control the flow rate of the liquid. Both the liquid inlet pipe A8 and the liquid inlet pipe B10 can be used for the input of waste liquid or medicine.

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

[0048] In the present application, the cyclone liquid mixer 2 includes a shell 201, and a first feed pipe 202 and a second feed pipe 203 are respectively arranged on both sides of the shell 201, and a third feed pipe 204 is arranged on the top of the cyclone liquid mixer 2, wherein the connection method of the pipelines on the cyclone liquid mixer 2 is specifically 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 shell 201.

[0049] In the present 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 liquid inlet pipe A8 and the third connecting pipe 9 .

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

[0051] The reactor body 1 is located above the return material screener 4 and is arranged as an inclined structure, and the crystal discharge port 12 is arranged at the inclined structure. The arrangement of the inclined structure facilitates the discharge of crystals.

[0052] In the present application, the reactor body 1 located above the inclined structure is 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 the present 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) of the reactor body 1 and the discharge port (crystal discharge port 12) of the reactor body 1 is 3.6-4.8m.

[0054] Workflow:

[0055] Operation of the cyclone mixer 2: After the fluorine-containing waste liquid enters the cyclone mixer 2, it is fully mixed with the seed particles and reagents driven by the cyclone. By adjusting the cyclone intensity and the reagent dosage, the supersaturation of the waste liquid is controlled within the set range, reducing the disintegration of the seed or the generation of fine particles caused by supersaturation. By adjusting the reagent dosage and the cyclone speed, the supersaturation is reduced to a stable range, significantly reducing the generation of fine particles.

[0056] Crystallization reaction in the circulating fluidized zone: The waste liquid and seed particles move downward to the circulating fluidized zone. In this zone, the seed particles gradually grow and crystallize to form calcium fluoride, and the particles are homogenized through continuous fluidization. The crystallization process in the circulating fluidized zone is continuous, which avoids the reduction of crystallization efficiency due to liquid retention or insufficient turbulence in local areas. The rising flow rate in the circulating fluidized zone of the reactor is 20m / h-100m / h.

[0057] Screening and circulation of the return screener 4: The liquid containing seed particles of different particle sizes reaches the return screener, and after separation by the screen, the large particles return to the circulating fluidized zone to continue the reaction, and the small particles fall into the reflux chamber 101. The small particles in the reflux chamber 101 are sent back into the cyclone mixer 2 under the action of the circulation pump 5 to achieve closed-loop operation.

[0058] Seed crystal growth and calcium fluoride purification: As the seed crystal particles grow, the seed crystal particle size gradually increases, and the screening efficiency gradually improves. After multiple cycles, the seed crystal achieves the purification of calcium fluoride in the repeated crystallization process.

[0059] Embodiment 2:

[0060] See also Figure 5 , 6 , combined with the basis of Example 1, the difference is that: the side wall of the third feed pipe 204 located in the housing 201 is provided with a plurality of mounting openings 205, and a mounting ring 206 is rotatably connected in the mounting opening 205, and a plurality of inclined blades 207 are arranged in a ring shape on the inner side of the mounting ring 206, and the third feed pipe 204 is located. By providing the mounting opening 205 in the side wall of the third feed pipe 204, the reaction reagent or reagent can be sprayed from the middle to the outside, which is convenient for the reagent to be fully mixed with the fluorine-containing waste liquid and the crystal, and by providing the blade 207, when the reagent liquid or waste liquid flows through the blade 207, the blade 207 will rotate, and the rotation of the blade 207 will generate thrust, so that the reagent is easier to mix with the fluorine-containing waste liquid and the crystal, and at the same time, the rotating blade generates thrust to the outside to prevent the liquid from flowing back into the third feed pipe 204.

[0061] A tilted cover may also be installed outside the installation opening 205 to prevent waste liquid from entering the inner side of the third feed pipe 204 .

[0062] In a possible embodiment, a high-pressure nozzle is arranged inside the installation port 205, and a connecting pipe of the high-pressure nozzle is connected to the third feed pipe 204 near the upper end. The arrangement of the high-pressure nozzle increases the force and speed of the agent injection.

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

[0064] In this embodiment, a mounting rod 13 is provided below the return material screener 4, and a mounting column 14 is provided on the mounting rod 13. A groove 403 is provided on the bottom surface of the return material screener 4, and the mounting column 14 is slidably matched with the groove 403. A vibration mechanism is provided inside the mounting column 14, and the vibration mechanism is in contact with the groove 403. The vibration mechanism can adopt a vibration motor, and a vibration force is generated when the vibration motor is running by connecting the output shaft of the vibration motor with the inside of the groove 403. Under the limiting action of the mounting column 14, the vibration of the return material screener 4 is to move back and forth in the vertical direction, thereby vibrating the crystals on the top of the screening plate 402, causing the crystals with small particles 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 is also convenient for the crystals with large particles to further crystallize.

[0065] Experimental Example 1:

[0066] A photovoltaic cell plant produces 50m3 of electronic grade hydrofluoric acid 3 / h, the F ion concentration is not less than 5000mg / L, and the pH value is 0.1. The patented technology of the present invention is used to convert it into high-purity calcium fluoride as the raw material for the preparation of electronic-grade hydrofluoric acid, thereby realizing the recycling of electronic-grade hydrofluoric acid. A cyclone mixer 2 is provided inside the reactor body 1, and the cross-sectional area of ​​the cyclone mixer 2 is 0.11m 2 , length 0.5m, inhaled reaction liquid is 8% Ca(OH) 2 , the diameter of the inlet B is DN25; the inner diameter of the circulation guide tube 3 inside the reactor body 1 is 1.2m and the length is 3.5m; the return material screener 4 at the bottom of the reactor body 1 has a return material cone angle of 30°, the screen plate 402 is 45° with the horizontal angle, and the screen plate is 50 mesh; the screening area at the bottom of the reactor body 1 is connected to the seed internal circulation pump 5, and its instantaneous speed entering the cyclone mixer 2 is 5.0m / s; the outlet pipe at the top of the reactor produces water normally. After the reactor runs for 4 hours, the discharge valve is opened to discharge the crystals inside the reactor body 1 out of the system to complete a 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 / h, the F ion concentration is not less than 4000mg / L, and the pH value is 0.1. The patented technology of the present invention is used to realize the recycling of electronic grade hydrofluoric acid. A cyclone mixer 2 is provided inside the reactor body 1, and the cross-sectional area of ​​the cyclone mixer 2 is 0.18m 2 , length 0.75m, inhaled reaction liquid is 8% Ca(OH) 2 , the diameter of the inlet B is DN32; the inner diameter of the circulation guide tube 3 inside the reactor body 1 is 1.5m and the length is 4.8m; the return material screener 4 at the bottom of the reactor body 1 has a return material cone angle of 45°, the screen plate has an angle of 60° with the horizontal, and the screen plate has a mesh size of 32; the screening area at the bottom of the reactor body 1 is connected to the seed internal circulation pump 5, and its instantaneous speed entering the mixer is 5.0m / s; the outlet pipe at the top of the reactor produces water normally. After the reactor runs for 4.5h, the discharge valve is opened to discharge the crystals inside the reactor body 1 out of the system to complete a 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] Device structure <![CDATA[Total flow rate (m 3 / h)]]> Hybrid Crystal size (μm) Calcium Fluoride Purity Experimental Example 1 50 Mixing / re-mixing 1850 98.3％ Experimental Example 2 80 Mixing / re-mixing 2030 98.7％ Comparative Example 1 50 Direct Mixing 150 70％ Comparative Example 2 50 Water cap liquid 100 85％

[0071] In Table 1, the same amount of reaction solution and hydrofluoric acid solution were added in Experimental Example 1, Experimental Example 2, Comparative Example 1, and Comparative Example 2, and the reaction solution and hydrofluoric acid solution were added in a certain ratio. The total flow rate of electronic grade hydrofluoric acid solution in Comparative Example 1 was 50 m 3 / h, F ion concentration is not less than 5000mg / L, pH value is 0.1, and the reaction solution is 8% Ca(OH) 2 Mix directly. Comparative Example 2 is electronic grade hydrofluoric acid with a total flow rate of 50m 3 / h with 8% Ca(OH) in reaction solution 2 The mixture is mixed by means of water cap distribution. It can be seen from the data in Table 1 that when the electronic grade hydrofluoric acid solution and the reaction solution are mixed by the device of the present invention, the obtained crystals are larger and the purity of calcium fluoride is also higher.

[0072] The above shows and describes 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 by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An electronic grade hydrofluoric acid in-situ recovery and reuse device, comprising a reactor body (1), characterized in that: The reactor body (1) is provided with a cyclone mixer (2) and a circulation guide tube (3), the cyclone mixer (2) is located on the inner side of the circulation guide tube (3) near the upper end, the circulation guide tube (3) is located between the cyclone mixer (2) and the inner wall of the reactor body (1), and the circulation guide tube (3) adopts a tapered design; A reflux chamber (101) is provided at the lower end of the reactor body (1), a return material screener (4) is provided at the upper part of the reflux chamber (101), a circulation pump (5) is provided at the reflux chamber (101) outside the reactor body (1), and a first connecting pipe (6) and a second connecting pipe (7) are connected to the circulation pump (5), the first connecting pipe (6) is in communication with the reflux chamber (101), and the second connecting pipe (7) is in communication with the cyclone mixer (2); The return material screener (4) comprises 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 conical surface of the return material cone (401) is arranged upward, and the outer side surface of the screening plate (402) is an inclined surface.

2. The electronic-grade hydrofluoric acid in-situ recycling device according to claim 1, characterized in that: The inner wall of the reactor body (1) is coated with an anti-scaling material. A liquid inlet pipe A (8) and a third connecting pipe (9) are provided through the two side surfaces of the reactor body (1). The third connecting pipe (9) is connected to the second connecting pipe (7). A liquid inlet pipe B (10) is provided through the top of the reactor body (1). A liquid outlet pipe (11) is also provided on the side of the reactor body (1). The liquid outlet pipe (11) is located between the liquid inlet pipe B (10) and the third connecting pipe (9) in a vertical position. A crystal discharge port (12) is provided at the lower end of the reactor body (1) above the return material screener (4).

3. The electronic-grade hydrofluoric acid in-situ recycling device according to claim 2, characterized in that: The cyclone liquid mixer (2) comprises a shell (201), a first feed pipe (202) and a second feed pipe (203) are respectively arranged on both sides of the shell (201), a third feed pipe (204) is arranged on the top of the cyclone liquid mixer (2), the first feed pipe (202) is connected to the liquid feed 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 liquid feed pipe B (10), and the lower end of the third feed pipe (204) extends into the shell (201).

4. The electronic-grade hydrofluoric acid in-situ recycling device according to claim 1, characterized in that: The cone angle of the return cone (401) is 30°-60°, and the outer inclined surface of the screening plate (402) is set to 45°-90°; The reactor body (1) is located above the return material screener (4) and is arranged as an inclined surface structure, and the crystal discharge port (12) is arranged at the inclined surface structure.

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

6. The electronic-grade hydrofluoric acid in-situ recovery and reuse device according to claim 4, characterized in that: The reactor body (1) located above the inclined structure is 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).

7. The electronic-grade hydrofluoric acid in-situ recovery and reuse device according to claim 6, characterized in that: The cross-sectional area of ​​the circulation guide tube (3) accounts for 50% to 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).

8. The electronic-grade hydrofluoric acid in-situ recovery and reuse device according to claim 5, characterized in that: The side wall of the third feed pipe (204) located inside the shell (201) is provided with a plurality of mounting openings (205), a mounting ring (206) is rotatably connected inside the mounting opening (205), and a plurality of inclined blades (207) are arranged in a ring shape on the inner side of the mounting ring (206).

9. The electronic-grade hydrofluoric acid in-situ recovery and reuse device according to claim 5, characterized in that: A spiral material guide plate (208) is arranged inside the housing (201).

10. The electronic-grade hydrofluoric acid in-situ recovery and reuse device according to claim 1, characterized in that: A mounting rod (13) is arranged below the return material screener (4), and a mounting column (14) is arranged on the mounting rod (13). A groove (403) is provided on the bottom surface of the return material screener (4), and the mounting column (14) is slidably matched with the groove (403). A vibration mechanism is arranged inside the mounting column (14), and the vibration mechanism is in contact with the groove (403).

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