A self-circulation multistage jet loop reactor and a method for using the same

Abstract

The application discloses a self-circulation multistage jet loop reaction device, which comprises a gourd-shaped reaction kettle body, wherein the reaction kettle body is connected by an upper small-diameter section and a lower large-diameter section; an annular gap backflow channel is formed between the inner wall of the reaction kettle body, a mixing cavity and a flow guide cylinder; a venturi injector is arranged at the top of the reaction kettle body, the top of the venturi injector is connected with an air inlet pipe, the throat of the venturi injector is connected with a solution feeding pipe, and a first distribution plate is coaxially arranged at the outlet of the venturi injector; the end of the diffusion section of the venturi injector is connected with the mixing cavity, a liquid distribution sieve plate is arranged at the bottom of the mixing cavity; the flow guide cylinder is arranged below the liquid distribution sieve plate and is divided into an empty cylinder section and a reaction section, the reaction section is provided with a filler layer, a second distribution plate is arranged at the inlet of the reaction section, and a central axial free flow guide pipe is arranged in the center of the filler layer. The self-circulation in the kettle is driven by the venturi jet power, an external circulation pump is not needed, the crystallization blockage can be avoided, and the continuous long-period production is realized.

Description

Technical Field

[0001] This invention relates to the field of electrolyte material preparation technology for ion batteries, specifically to a self-circulating multi-stage jet recirculation reactor for the synthesis of lithium hexafluorophosphate and its usage method. Background Technology

[0002] The synthesis of lithium hexafluorophosphate (LiPF6) typically involves the reaction of lithium fluoride (LiF) with phosphorus pentafluoride (PF5) in anhydrous hydrofluoric acid (HF) solvent. This reaction is strongly exothermic, the products are prone to crystallization and decomposition, and HF is highly volatile at high temperatures. Traditional stirred tank reactors require an external circulation pump, which presents problems such as leakage risk, high energy consumption, and long reaction times. Furthermore, microchannel reactors are prone to clogging.

[0003] Therefore, there is an urgent need for a reactor that can operate at low temperatures, is resistant to clogging, has high mass transfer, and is easy to scale up. Summary of the Invention

[0004] The purpose of this invention is to provide a self-circulating multi-stage jet recirculation reaction device and its usage method, which at least partially solves one of the technical problems in the related art.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A self-circulating multi-stage jet recirculation reactor includes a gourd-shaped reactor body, which is composed of an upper small-diameter section and a lower large-diameter section. The upper small-diameter section is provided with a mixing chamber, and the lower large-diameter section is provided with a guide tube. An annular reflux channel is formed between the inner wall of the reactor body, the mixing chamber, and the guide tube. A Venturi injector is located at the top center of the reactor body. The top inlet of the Venturi injector is connected to the air inlet pipe, and the side opening at the throat is connected to the solution feed pipe. A first distribution plate is coaxially arranged at the outlet of the Venturi injector. The end of the diffusion section of the Venturi injector is integrated with the mixing chamber. A liquid distribution sieve plate is provided at the bottom of the mixing chamber. The guide tube is located below the liquid distribution sieve plate and is coaxial with it. The internal space of the guide tube is divided into an upper empty section and a lower reaction section. The reaction section is equipped with a packing layer. A second distribution plate is provided at the inlet of the reaction section. A vertically penetrating central axial free flow guide tube is provided in the center of the packing layer. The bottom of the guide tube is open and communicates with the bottom space of the reactor body. The top of the annular reflux channel is connected to the side suction port of the Venturi injector, and the bottom is connected to the space below the guide tube.

[0006] Furthermore, the diameter of the mixing chamber is smaller than the diameter of the guide tube.

[0007] Furthermore, the ratio of the cross-sectional area of ​​the mixing chamber to the cross-sectional area of ​​the upper small-diameter section of the vessel body is 0.10-0.12, and the inner diameter of the mixing chamber is 8-10 times the inner diameter of the Venturi throat.

[0008] Furthermore, the vertical distance between the lower surface of the liquid distribution screen plate and the upper edge of the guide tube is 0.3-0.5 times the inner diameter of the guide tube, and the height difference between the upper edge of the guide tube and the upper lateral suction port of the Venturi injector is ≥100mm.

[0009] Furthermore, the liquid distribution sieve plate, the first distribution plate and the second distribution plate are all conical hole sieve plates with a sieve hole diameter of 8-12mm and an opening rate of 30-40%.

[0010] Furthermore, the packing layer is a flow-guiding grid-structured packing, and the inner diameter of the axial free-flow guide pipe is 1 / 5 to 1 / 4 of the packing layer diameter.

[0011] Furthermore, the reactor body has a backwashing port on the side wall of the upper small diameter section, located above the liquid distribution screen plate.

[0012] Furthermore, the bottom of the reactor body is provided with a discharge port, and a filter element is provided inside the discharge port.

[0013] Furthermore, the outer wall of the reactor body is provided with a jacketed cooling system.

[0014] The present invention also discloses a method of using a self-circulating multi-stage jet recirculation reactor, comprising the following steps: Feed: PF5 gas is introduced through the inlet pipe at the top of the Venturi injector, and the HF solution of LiF is introduced through the solution feed pipe at the throat of the Venturi injector. Jet mixing: The high-speed injection of PF5 creates a negative pressure at the throat of the Venturi injector, which entrains the LiF solution and the circulating liquid returning from the annular reflux channel, thus achieving gas-liquid mixing; Cavity mixing and preliminary reaction: After being rectified by the first distribution plate, the mixed fluid enters the mixing cavity and completes the preliminary reaction under the action of strong turbulence; Fluid rectification: The material discharged from the mixing chamber is rectified by the liquid distribution screen plate, breaking the jet into a uniform group of droplets; Secondary distribution and deep reaction: After the rectified fluid is distributed secondary by the second distribution plate, it enters the packing layer at the bottom of the guide tube to complete the residual reaction and maturation; Self-circulation: The fluid after the reaction flows out from the bottom of the guide tube, flows back upward through the annular return channel, and re-enters the negative pressure zone of the Venturi ejector to participate in the circulation.

[0015] The beneficial effects of this invention are: (1) Energy saving and safety: The internal circulation of the vessel is driven by the power of Venturi jet, eliminating the need for an external circulation pump, eliminating the risk of HF leakage, and reducing energy consumption by more than 50%.

[0016] (2) Anti-clogging long cycle: Conical large hole screen plate + low temperature operation + online backflushing, no clogging for more than 60 consecutive days.

[0017] (3) Enhanced heat transfer: The central axial free flow guide tube guides the low temperature circulating liquid to eliminate local overheating and the bed temperature uniformity is ±2℃.

[0018] (4) Fast reaction rate: The reaction zone takes about 25 minutes to pass through once (due to the circulation ratio of 10-20, the actual total effective reaction time is much longer than this), which is significantly better than the 1-3 hours of traditional stirred tank reactors.

[0019] (5) High conversion rate: raw material conversion rate ≥99.5%, product insoluble matter <100ppmw.

[0020] (6) No scale-up effect: The two-stage distribution plate and proportional design ensure that the performance does not degrade during high-capacity production. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0022] In the diagram: 1-Upper small diameter section, 2-Lower large diameter section, 3-Equipment flange, 4-Venturi ejector, 5-First anti-clogging distribution plate, 6-Mixing chamber, 7-Anti-clogging liquid distribution screen plate, 8-Guide cylinder, 9-Second anti-clogging distribution plate, 10-Packaging layer, 11-Central axial free flow guide pipe, 12-Annular reflux channel, 13-Sintered metal filter element, 14-Backwash port, 15-Side suction port, 16-Jacket cooling.

[0023] The arrows indicate the direction of fluid flow.

[0024] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0026] like Figure 1As shown, this embodiment provides a self-circulating multi-stage jet recirculation reactor, including a gourd-shaped reactor body. The reactor body is formed by an upper small-diameter section 1 and a lower large-diameter section 2 connected by an equipment flange 3. The outer walls of the upper small-diameter section 1 and the lower large-diameter section 2 are respectively provided with jacketed cooling 16.

[0027] A mixing chamber 6 is coaxially arranged in the upper small-diameter section 1, and a coaxial guide tube 8 is arranged in the lower large-diameter section 2. The diameter of the mixing chamber 6 is smaller than the diameter of the guide tube 8. An annular reflux channel 12 is formed between the inner wall of the reactor body, the mixing chamber 6, and the guide tube 8, which are connected vertically.

[0028] A Venturi injector 4 is located at the top center of the reactor body. The top inlet of the Venturi injector 4 is connected to the PF5 air inlet pipe, the throat side opening is connected to the LiF / HF solution feed pipe, and a side suction port 15 is provided to communicate with the annular reflux channel 12.

[0029] A first anti-clogging distribution plate 5 is coaxially arranged at the outlet of the Venturi injector 4. The end of the diffusion section of the Venturi injector 4 is integrated with the mixing chamber 6. An anti-clogging liquid distribution screen plate 7 is provided at the bottom of the mixing chamber 6.

[0030] In this embodiment, the ratio of the cross-sectional area of ​​the mixing chamber 6 to the cross-sectional area of ​​the upper small-diameter section 1 is 0.10-0.12, and the inner diameter of the mixing chamber is 8-10 times the inner diameter of the throat of the Venturi injector 4.

[0031] The guide tube 8 is located below the liquid distribution screen plate 7 and is coaxial with it. The vertical distance between the lower surface of the liquid distribution screen plate 7 and the upper edge of the guide tube 8 is 0.3-0.5 times the inner diameter of the guide tube (0.35 times in this embodiment), and the height difference between the upper edge of the guide tube 8 and the upper lateral suction port 15 of the Venturi injector 4 is ≥100mm.

[0032] The internal space of the guide tube 8 is divided into an upper empty section and a lower reaction section. The empty section is unfilled, and a second anti-clogging distribution plate 9 is installed at its lower end. Below the second anti-clogging distribution plate 9, there is a packing layer 10. A vertically penetrating central axial free-flow guide tube 11 is provided in the center of the packing layer 10. The bottom of the guide tube 8 is open and communicates with the bottom space of the reactor body.

[0033] In this embodiment, the packing layer 10 is a flow-guiding grid-structured packing with a specific surface area of ​​250-300 m² / m³ and a packing layer height of 1.5-3.0 m; the inner diameter of the central axial free-flow guide pipe is 1 / 5-1 / 4 of the packing layer diameter.

[0034] The top of the annular reflux channel 12 is connected to the side intake port 15 of the Venturi injector 4, and the bottom is connected to the space below the guide tube 8.

[0035] The bottom of the reactor body is provided with a discharge port, which is equipped with a sintered metal filter element 13 to intercept unreacted LiF solid particles. The reactor body is provided with a backwashing interface 14 on the side wall of the upper small diameter section 1 above the liquid distribution sieve plate 7, which is used to connect hot HF solvent for online backwashing cleaning.

[0036] In this embodiment, the anti-clogging liquid distribution sieve plate 7, the first anti-clogging distribution plate 5, and the second anti-clogging distribution plate 9 are all conical hole sieve plates with a sieve hole diameter of 8-12mm, an opening rate of 30-40%, and an electrochemically polished surface to Ra<0.8μm.

[0037] In this embodiment, the method of using the self-circulating multi-stage jet recirculation reactor includes the following steps: The operating temperature should be controlled at 5~15℃ and the pressure at 0.45-0.55MPa (gauge pressure) to prevent excessive HF volatilization.

[0038] Feed: PF5 gas is introduced from the inlet pipe at the top of the Venturi injector 4, and LiF / HF solution is introduced from the solution feed pipe at the throat of the Venturi injector 4. Jet mixing: The high-speed jet of PF5 creates a negative pressure at the throat of the Venturi injector 4, drawing in the LiF / HF solution and the circulating liquid from the annular reflux channel 12 together, achieving millisecond-level gas-liquid mixing. Cavity mixing and preliminary reaction: After being dispersed by the first anti-blocking distribution plate 5, the mixed fluid enters the mixing cavity 6 and completes the preliminary reaction under the action of strong turbulence; Fluid rectification: The discharge from the mixing chamber 6 is rectified by the anti-clogging liquid distribution screen plate 7, breaking the jet into a uniform group of droplets; Secondary distribution and deep reaction: After the rectified fluid is distributed secondary by the second anti-clogging distribution plate 9, it enters the packing layer at the bottom of the guide tube for deep reaction, completing the residual reaction and maturation; Self-circulation: The fluid after the reaction flows out from the bottom of the guide tube 8, turns upward and enters the annular reflux channel 12, and is drawn back by the side suction port 15 of the Venturi injector 4, forming self-circulation (circulation ratio 10-20); the product solution is taken out from the bottom of the vessel, and the unreacted LiF solid is intercepted by the sintered metal filter element 13 and returned to the reaction zone.

[0039] This invention utilizes Venturi jet power to drive self-circulation within the reactor, eliminating the need for an external circulation pump. Rapid mixing and deep reaction are achieved through multi-stage zoned reaction. Double anti-clogging measures, including a conical large-pore sieve plate (anti-clogging liquid distribution sieve plate 7, first anti-clogging distribution plate 5, and second anti-clogging distribution plate 9) and a central axial free-flow guide pipe 11, prevent crystallization blockage. The two-stage distribution plate eliminates scale-up effects. The device operates at a low temperature of 5-15℃ to prevent HF volatilization and LiPF6 decomposition. The reaction zone throughput time is approximately 25 minutes, with a raw material conversion rate ≥99.5%, energy consumption reduced by more than 50%, enabling continuous long-cycle production.

[0040] The following experimental examples further illustrate the beneficial effects of the present invention.

[0041] Experimental Example 1 (10,000-ton-per-year LiPF6 plant) The specific dimensions are as follows: Upper small diameter section 1: inner diameter 1800mm, height 2000mm;

[0042] Lower large-diameter section 2: inner diameter 3200mm, height 4800mm;

[0043] Equipment flange 3: DN1600 PN16, material Hastelloy C276.

[0044] Venturi injector 4: throat diameter Φ90mm, PF5 inlet pressure 0.85MPaG. When the PF5 feed flow rate is 1.2t / h, the throat air velocity is about 35m / s, generating sufficient negative pressure to drive self-circulation.

[0045] First anti-clogging distribution plate 5: tapered hole Φ12mm, opening ratio 35%, surface polishing Ra=0.6μm.

[0046] Mixing chamber 6: inner diameter Φ800mm, height 1000mm (the ratio of cross-sectional area to the cross-sectional area of ​​the upper vessel body is approximately 0.11).

[0047] Anti-clogging liquid distribution screen plate 7: tapered hole Φ12mm, opening rate 35%.

[0048] The distance between the liquid distribution sieve plate and the guide tube is 0.35 times the inner diameter of the guide tube (2600mm), which is 910mm.

[0049] Guide tube 8: Inner diameter Φ2600mm, height 4000mm, upper empty section height 1500mm, lower filler layer height 2500mm.

[0050] Second anti-clogging distribution plate 9: Same as the first anti-clogging distribution plate.

[0051] Packing layer 10: Guided mesh structured packing, with a specific surface area of ​​280 m² / m³ and a height of 2500 mm.

[0052] Central axial free-flow guide tube 11: inner diameter Φ500mm (1 / 5.2 of the packing layer diameter, wall thickness 8mm).

[0053] Annular reflux channel 12: 300mm wide (single side).

[0054] Sintered metal filter element 13: 5μm precision, made of Hastelloy C276.

[0055] Backwash port 14: DN40, can be connected to 5~10℃ hot HF solvent for online cleaning.

[0056] Jacketed cooling 16: Pass chilled brine through to control the temperature inside the vessel at 5~15℃.

[0057] Operating parameters: PF5 flow rate 1.2 t / h, LiF / HF solution (12 wt% flow rate 4.5 t / h, molar ratio PF5:LiF = 1.02:1). Feed temperature 5~10℃, reaction temperature 8±3℃, pressure 0.5 MPaG. Circulation ratio approximately 15, residence time in the reaction zone approximately 25 minutes per pass (effective reaction zone volume approximately 5 m³, total circulation flow rate approximately 13.3 m³ / h, mother liquor buffer volume approximately 30 m³, ensuring stable crystallization in subsequent stages). Continuous operation results: no blockages for 60 days, raw material conversion rate ≥99.5%, product purity 99.99%, insoluble matter ≤80 ppmw, unit product energy consumption reduced by 55% compared to traditional external circulation stirred tank reactors. Extremely low HF volatility, safe operating environment.

[0058] Experimental Example 2: A LiPF6 plant with an annual production capacity of 20,000 tons (similar scale-up) Maintaining the exact same geometric proportions as in Experimental Example 1 (upper diameter ratio of the gourd shape, mixing chamber / upper cross-sectional area ratio of 0.11, liquid distribution sieve plate to guide tube distance ratio of 0.35, circulation ratio of 15, etc.), similar scale-up was performed based on a 2x increase in production capacity. The linear scaling factor k = 2^1 / 3 ≈ 1.26. Specific dimensions are as follows: Upper small diameter section 1: Inner diameter 1800×1.26 ≈ 2268mm, take 2300mm; Height 2000×1.26=2520mm, take 2500mm.

[0059] Lower large diameter section 2: Inner diameter 3200×1.26 ≈ 4032mm, take 4000mm; Height 4800×1.26 ≈ 6048mm, take 6000mm.

[0060] Equipment flange 3: DN2000 PN16, material Hastelloy C276.

[0061] Venturi ejector 4: throat diameter Φ90×1.26 ≈ 113mm, take Φ115mm. PF5 feed flow rate is 2.4t / h, inlet pressure is still 0.85MPaG, throat gas velocity is about 35m / s (same as in Experimental Example 1).

[0062] First anti-clogging distribution plate 5: tapered hole Φ12mm, opening rate 35%, surface polishing Ra=0.6μm (hole diameter remains unchanged, number increases proportionally to area).

[0063] Mixing chamber 6: Inner diameter Φ800×1.26 ≈ 1008mm, take Φ1000mm; Height 1000×1.26=1260mm, take 1300mm.

[0064] Anti-clogging liquid distribution screen plate 7: Same parameters as the first anti-clogging distribution plate.

[0065] Distance between liquid distribution sieve plate and guide tube: Inner diameter of guide tube = 2600×1.26 ≈ 3276mm, take 3300mm; Distance = 3300×0.35 = 1155mm.

[0066] Guide tube 8: Inner diameter Φ3300mm, height 5000mm (upper empty section 1900mm, lower filler layer 3100mm).

[0067] Second anti-clogging distribution plate 9: Same as the first anti-clogging distribution plate.

[0068] Structured filler layer 10: specific surface area 280 m² / m³, height 3100 mm.

[0069] Central axial free-flow guide tube 11: inner diameter = 3300 / 5.2 ≈ 635mm, take Φ650mm, wall thickness 10mm.

[0070] Annular reflux channel 12: Width = 4000-3300 / 2 = 350mm (single side).

[0071] Sintered metal filter element 13: 5μm precision, with the filtration area scaled up proportionally.

[0072] Backwash port 14: DN50.

[0073] Jacketed cooling 16: Pass chilled brine through to control the temperature inside the vessel at 5~15℃.

[0074] Operating parameters were scaled up proportionally: PF5 flow rate 2.4 t / h, LiF / HF solution (12 wt%) flow rate 9.0 t / h, molar ratio still 1.02:1. Feed temperature 5~10℃, reaction temperature 8±3℃, pressure 0.5 MPaG. Circulation ratio 15, effective reaction zone volume approximately 10 m³ (twice that of Experimental Example 1), total circulation flow rate approximately 26.6 m³ / h, single-pass residence time in the reaction zone still approximately 30 minutes. Mother liquor buffer volume approximately 60 m³. Continuous operation results showed: conversion rate ≥99.5%, product purity 99.99%, insoluble matter ≤80 ppmw, energy consumption reduced by 55% compared to traditional processes, and performance completely consistent with Experimental Example 1, verifying that this invention has no scale-up effect.

[0075] This invention is applicable to the low-temperature continuous large-scale production of lithium hexafluorophosphate, especially suitable for crystallization processes that require mother liquor buffering, and can also be used in other low-temperature, easily crystallizing, and strongly exothermic gas-liquid-solid reaction systems.

[0076] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

[0077] If the terms "first" or "second" are used in this document to define components, those skilled in the art should know that the use of "first" or "second" is merely for the convenience of describing the invention and simplifying the description, and unless otherwise stated, the above terms have no special meaning.

[0078] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0079] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. A self-circulating multi-stage jet recirculation reaction device, characterized in that: The reactor includes a gourd-shaped reactor body, which is composed of an upper small-diameter section and a lower large-diameter section. The upper small-diameter section contains a mixing chamber, and the lower large-diameter section contains a flow guide tube. An annular reflux channel is formed between the inner wall of the reactor body, the mixing chamber, and the flow guide tube. A Venturi injector is located at the top center of the reactor body. The top inlet of the Venturi injector is connected to the air inlet pipe, and the side opening at the throat is connected to the solution feed pipe. A first distribution plate is coaxially arranged at the outlet of the Venturi injector. The end of the diffusion section of the Venturi injector is integrated with the mixing chamber. A liquid distribution sieve plate is provided at the bottom of the mixing chamber. The guide tube is located below the liquid distribution sieve plate and is coaxial with it. The internal space of the guide tube is divided into an upper empty section and a lower reaction section. The reaction section is equipped with a packing layer. A second distribution plate is provided at the inlet of the reaction section. A vertically penetrating central axial free flow guide tube is provided in the center of the packing layer. The bottom of the guide tube is open and communicates with the bottom space of the reactor body. The top of the annular reflux channel is connected to the lateral intake port of the Venturi injector, and the bottom is connected to the space below the guide tube.

2. The self-circulating multi-stage jet recirculation reactor according to claim 1, characterized in that: The diameter of the mixing chamber is smaller than the diameter of the guide tube.

3. The self-circulating multi-stage jet recirculation reactor according to claim 2, characterized in that: The ratio of the cross-sectional area of ​​the mixing chamber to the cross-sectional area of ​​the upper small-diameter section of the vessel body is 0.10-0.12, and the inner diameter of the mixing chamber is 8-10 times the inner diameter of the Venturi throat.

4. The self-circulating multi-stage jet recirculation reactor according to claim 1, characterized in that: The vertical distance between the lower surface of the liquid distribution screen plate and the upper edge of the guide tube is 0.3-0.5 times the inner diameter of the guide tube, and the height difference between the upper edge of the guide tube and the upper lateral suction port of the Venturi injector is ≥100mm.

5. The self-circulating multi-stage jet recirculation reactor according to claim 1, characterized in that: The liquid distribution sieve plate, the first distribution plate and the second distribution plate are all conical hole sieve plates with a sieve hole diameter of 8-12mm and an opening rate of 30-40%.

6. The self-circulating multi-stage jet recirculation reactor according to claim 1, characterized in that: The packing layer is a flow-guiding grid-structured packing, and the inner diameter of the axial free-flow guide pipe is 1 / 5 to 1 / 4 of the packing layer diameter.

7. The self-circulating multi-stage jet recirculation reactor according to claim 1, characterized in that: The reactor body has a backwashing port on the side wall of the upper small diameter section, located above the liquid distribution screen plate.

8. The self-circulating multi-stage jet recirculation reactor according to any one of claims 1-7, characterized in that: The bottom of the reactor body is provided with a discharge port, and a filter element is installed inside the discharge port.

9. The self-circulating multi-stage jet recirculation reactor according to any one of claims 1-7, characterized in that: The outer wall of the reactor body is equipped with a jacketed cooling system.

10. A method of using a self-circulating multi-stage jet recirculation reactor, based on the self-circulating multi-stage jet recirculation reactor according to any one of claims 1-9, characterized in that... Includes the following steps: Feed: PF5 gas is introduced through the inlet pipe at the top of the Venturi injector, and the HF solution of LiF is introduced through the solution feed pipe at the throat of the Venturi injector. Jet mixing: The high-speed injection of PF5 creates a negative pressure at the throat of the Venturi injector, which entrains the LiF solution and the circulating liquid returning from the annular reflux channel, thus achieving gas-liquid mixing; Cavity mixing and preliminary reaction: After being rectified by the first distribution plate, the mixed fluid enters the mixing cavity and completes the preliminary reaction under the action of strong turbulence; Fluid rectification: The material discharged from the mixing chamber is rectified by the liquid distribution screen plate, breaking the jet into a uniform group of droplets; Secondary distribution and deep reaction: After the rectified fluid is distributed secondary by the second distribution plate, it enters the packing layer at the bottom of the guide tube to complete the residual reaction and maturation; Self-circulation: The fluid after the reaction flows out from the bottom of the guide tube, flows back upward through the annular return channel, and re-enters the negative pressure zone of the Venturi ejector to participate in the circulation.

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