A lithium difluorophosphate crude product dissolving device

Abstract

The application discloses a lithium difluorophosphate crude product dissolving equipment, which comprises a dissolving kettle, an auxiliary stirring part, a lower crushing structure and a guide limiting structure. The dissolving kettle comprises a kettle body, a crude product feeding cavity column, a solvent feeding cavity pipe and a lower discharge valve. The auxiliary stirring part comprises a dissolving stirring motor fixed on the top surface center of the kettle body. The lower end of the dissolving stirring motor is connected with a plurality of stirring rods. The plurality of stirring rods are provided with hollow drums corresponding to the positions of the inner wall of the top of the kettle body. The hollow drums are connected with outer air pipes. After the outer air pipes are ventilated, the plurality of stirring rods are lengthened. The lower crushing structure comprises a crushing frame arranged on the bottom of the inside of the kettle body. The bottom of the crushing frame is attached to the kettle body. The middle part of the crushing frame is provided with a butt joint seat. The guide limiting structure comprises a first guide part arranged on the inner wall of the kettle body. The first guide part is movably provided with a second guide part. The side, close to the central axis of the kettle body, of the second guide part is provided with a matching part. The application can improve the content of the filtered lithium difluorophosphate.

Description

Technical Field

[0001] This invention relates to a lithium difluorophosphate processing device, and more particularly to a crude lithium difluorophosphate dissolution device. Background Technology

[0002] Lithium difluorophosphate (LiDFP) is a key additive in lithium-ion battery electrolytes, effectively improving high-temperature performance and cycle life, leading to increasing market demand. However, the insoluble matter content is a crucial parameter for evaluating the quality of LiDFP products. Excessive insoluble matter directly increases battery internal resistance and accelerates capacity decay, severely impacting overall battery performance and safety. Affected by raw material purity and fluctuations in reaction conditions, the insoluble matter content in products is often high, making it difficult to consistently meet market and customer requirements of ≤500ppm, resulting in low product qualification rates. This low insoluble matter content leads to a large number of reworked and even scrapped products. Currently, LiDFP is filtered before use to reduce its insoluble matter content.

[0003] Existing technologies employ only a single filtration or sedimentation process, which cannot achieve complete removal of large particulate solid impurities, colloidal and viscous impurities. Large particulate impurities easily clog filtration equipment, while colloidal / viscous impurities are difficult to separate through sedimentation alone. Therefore, existing technologies dissolve the crude lithium difluorophosphate before filtration. During the dissolution process, solvents such as ethers or alcohols are added before stirring and dissolving. However, in the later stages of dissolution, some dissolved substances at the bottom, being far from the dissolution area, are difficult to completely dissolve due to their own solubility and the solvent's dissolution effect at the end of the reaction. They are carried to the next filtration area along with the insoluble matter and intercepted, resulting in the loss of some useful substances in lithium difluorophosphate and thus reducing the overall utilization rate.

[0004] Therefore, this case aims to provide a crude lithium difluorophosphate dissolution device that can not only stir normally in the early stage to ensure that the lithium difluorophosphate is fully mixed and dissolved, but also fully crush the bottom of the dissolution device in the later stage to crush and float the dissolved matter at the bottom, thereby achieving the effect of thoroughly utilizing lithium difluorophosphate and increasing the content of lithium difluorophosphate after filtration. This is the research objective of this case. Summary of the Invention

[0005] This invention provides a crude lithium difluorophosphate dissolution device, which can effectively solve the above-mentioned problems.

[0006] This invention is implemented as follows: A crude lithium difluorophosphate dissolution apparatus, comprising: A dissolving vessel includes a vessel body for holding liquids, wherein the top of the vessel body is provided with a crude product feed chamber column and a solvent feed chamber pipe, and the lower end of the vessel body is provided with a lower discharge valve flush with the bottom surface of the vessel body; The auxiliary stirring component includes a dissolving and stirring motor fixed at the center of the top surface of the vessel body. The lower end of the dissolving and stirring motor is connected to a multi-segment stirring rod. A hollow drum is provided on the multi-segment stirring rod at a position corresponding to the inner wall of the top of the vessel body. The hollow drum is connected to an external vent pipe. When the external vent pipe is vented, the multi-segment stirring rod is extended. The lower grinding structure includes a grinding frame disposed at the bottom of the inside of the vessel body. The bottom of the grinding frame is attached to the vessel body. A docking seat is provided in the middle of the grinding frame. The multi-segment stirring rod is extended and connected to the docking seat, and drives the grinding frame to rotate along the bottom of the vessel body. The guiding and limiting structure includes a first guiding component disposed on the inner wall of the vessel body, a second guiding component movably mounted on the first guiding component, and a mating component disposed on the side of the second guiding component near the central axis of the vessel body. When the grinding frame rotates, the outer edge of the grinding frame expands outward and is embedded in the mating component, so that the entire grinding frame can rotate along the first guiding component through the second guiding component.

[0007] As a further improvement, the multi-segment stirring rod includes a porous connecting pipe connected to a dissolving stirring motor. The lower end of the porous connecting pipe is connected to a thickening pipe, and the lower end of the thickening pipe is provided with an elastic pressure pipe. The projected position of the elastic pressure pipe is directly opposite the mating part.

[0008] As a further improvement, the elastic pressure tube includes an elastic seat located at the bottom of the inner cavity of the thickened tube, and a pressure tube is connected to the lower end of the elastic seat, the pressure tube penetrating the bottom surface of the thickened tube.

[0009] As a further improvement, the hollow drum includes a hollow chamber disposed at the lower end of the upper cover of the vessel body. The hollow chamber is connected to an external vent pipe via an external conduit, and the hollow chamber is connected to the communication hole of a porous connecting pipe.

[0010] As a further improvement, the grinding frame includes a grinding frame body that is movably fitted to the bottom of the vessel body, and an elastic metal ring is provided around the outer edge of the grinding frame body, the outer side of which is movably fitted with a mating part.

[0011] As a further improvement, the grinding frame body includes a small grinding disc located on the top surface of the lower discharge valve and a large grinding disc located outside the conduction limiting structure. The small grinding disc and the large grinding disc are connected by several grinding arms.

[0012] As a further improvement, the grinding arm is an arc-shaped structure that conforms to the curvature of the bottom surface of the vessel. Several fins are provided on the outer side of the grinding arm, and the soluble substances between adjacent grinding arms can be lifted by the fins.

[0013] As a further improvement, the elastic metal ring includes an elastic arc ring connected to the top of the large grinding disc, and the outer side of the elastic arc ring is integrally formed with several clamping grooves, which cooperate with mating parts.

[0014] As a further improvement, the first conductive element is an annular band connected to the inner wall of the vessel, the middle of which is recessed inward and forms several external conductive holes; the second conductive element is a zigzag band embedded in the recessed area of ​​the annular band, the recessed area of ​​which has several internal conductive holes.

[0015] As a further improvement, the mating component consists of several ribs disposed inside the Z-shaped belt. The ribs are movably fitted with the grinding frame, and the distance between the grinding frame and the ribs decreases as the grinding frame rotates faster.

[0016] The beneficial effects of this invention are: In the later stages of dissolution in existing technologies, some dissolved substances precipitated at the bottom are far from the dissolution area and are difficult to completely dissolve by their own and the solvent's dissolution effect at the end of the reaction. They are carried to the next stage of filtration area along with the insoluble matter and are intercepted and filtered, resulting in the loss of some useful substances in lithium difluorophosphate and thus reducing the overall utilization rate. Therefore, this invention, through the setting of a lower grinding structure, allows multiple stirring rods to extend and connect to the docking seat of the grinding frame when the conventional stirring time ends and the stirring stage is reached. Thus, when the multiple stirring rods rotate, they can drive the entire grinding frame to rotate, thereby grinding the remaining dissolved substances mixed with insoluble matter at the bottom of the entire reactor, which can promote the overall reaction.

[0017] The multi-segment stirring rod needs to serve as a series connection to the grinding frame. Therefore, the multi-segment stirring rod of this invention is divided into three segments: a perforated connecting pipe that allows air to pass through, a thickened pipe that bears the main stirring action, and an elastic pressure pipe that moves in conjunction with the grinding frame. When inert gas is introduced into the perforated connecting pipe, the elastic pressure pipe can pop out and cooperate with the grinding frame, driving the grinding frame to rotate. Since inert gas is introduced, there is no need to worry about safety hazards even if air leakage occurs.

[0018] In order to improve the efficiency of the initial stirring process by driving the grinding frame only after dissolution, the elastic pressure tube of the present invention is provided with an elastic seat that can move up and down. When the elastic seat is squeezed by inert gas, it will fall down, push out the lower pressure tube and make the lower pressure tube cooperate with the docking seat. After the inert gas is depressurized, the elastic seat will reset and the lower pressure tube will reset and separate from the docking seat.

[0019] During the gas intake process of the porous connecting pipe, it is necessary to ensure the guiding effect of the inert gas. Although its overflow into the vessel body will not affect the dissolution process, it will affect the fit between the pressure pipe and the docking seat. Therefore, this invention forms a guide on the outside of the porous connecting pipe by setting a hollow drum, so that the gas intake process can only occur in the internal area of ​​the hollow drum. Through the guidance of the small space, not only can the pressure of the gas intake be guaranteed, but the possibility of leakage can also be reduced.

[0020] When grinding the vessel body, the grinding frame needs to ensure not only the grinding effect but also its own stability. Therefore, this invention allows the grinding frame body to contact the bottom of the vessel body for grinding, while the elastic metal ring forms a link with the mating parts, thereby achieving a stable grinding effect.

[0021] During the grinding process, the main body of the grinding frame grinds not only the bottom, but the entire bottom area. This invention forms a grinding surface covering the entire bottom surface of the vessel by setting small grinding discs, large grinding discs and several grinding arms, thereby ensuring that the tiny soluble substances at the end of the dissolution stage can completely react with the solvent.

[0022] If there are particles moving with the grinding arms, the present invention also provides several fins on the outside of the grinding arms. The fins will fan as the grinding arms rotate, thereby lifting the soluble material between the two grinding arms upward, thus improving the dissolution efficiency.

[0023] During the entire grinding process, although the shape of the grinding frame fits the bottom area of ​​the vessel, if it is simultaneously rubbed and stuck by a large amount of insoluble matter during the long-term repetitive rotation, it may deviate. Therefore, the present invention uses a conductive limiting structure to allow the grinding frame to form a linkage with the mating part on the second conductive part when rotating, driving the second conductive part to rotate along the first conductive part, thereby ensuring the stability of the grinding frame. Furthermore, since the first and second conductive parts themselves have a conductive effect, soluble or insoluble matter does not accumulate, and it does not affect the normal reaction.

[0024] If particles accumulate in the first and second conductive components while they are connected and guided, rotation will be easily obstructed, and insoluble matter will easily get stuck at that position and cannot be discharged. Therefore, the first and second conductive components of this invention are not only configured as annular and U-shaped bands that are recessed and fitted together, but also have outer and inner conductive holes in the annular and U-shaped bands. This allows particles to pass smoothly through the conductive holes when the annular and U-shaped bands are not in motion, and they are not easily blocked by the conductive components.

[0025] The mating parts are pre-installed when they mate with the elastic metal ring. They are pre-clamped together with the ribs via the clamping groove. After the elastic metal ring rotates with the grinding frame, the elastic arc ring expands and deforms outward, making the clamping groove and the ribs fit even tighter and preventing them from disengaging when the rotation speed increases. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0028] Figure 2 This is a top view of the structure of the present invention.

[0029] Figure 3 This is the present invention. Figure 2 Cross-sectional view at point AA.

[0030] Figure 4 This is the present invention. Figure 3 A magnified view of region A in the middle.

[0031] Figure 5 This is the present invention. Figure 3 A magnified view of region B in the middle.

[0032] Figure 6 This is a schematic diagram of the structure of the elastic pressure tube of the present invention.

[0033] In the picture: Dissolving vessel 1, vessel body 101, crude product feed chamber column 102, solvent feed chamber pipe 103, lower discharge valve 104, auxiliary stirring component 2, dissolving stirring motor 201, multi-segment stirring rod 202, porous connecting pipe 2021, thickened pipe 2022, elastic pressure pipe 2023, elastic seat 20231, lower pressure pipe 23232, hollow drum 203, hollow chamber 2031, outer conduit 2032, external vent pipe 204, lower crushing structure 3. Grinding frame 301, grinding frame body 3011, small grinding disc 30111, large grinding disc 30112, grinding arm 30113, elastic metal ring 3012, elastic arc ring 30121, clamping groove 30122, docking seat 302, guiding and limiting structure 4, first guiding component 401, annular belt 4011, outer guiding hole 4012, second guiding component 402, Z-shaped belt 4021, inner guiding hole 4022, mating component 403. Detailed Implementation

[0034] All embodiments of the present invention are intended to fall within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0035] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating that the purpose, technical solution, and advantages of the method are clearer. The technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort indicate or imply the relative importance of the indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] Reference Figures 1-6As shown, a crude lithium difluorophosphate dissolution device includes: a dissolution vessel 1, comprising a vessel body 101 for holding liquid, wherein the top of the vessel body 101 is provided with a crude product feed chamber column 102 and a solvent feed chamber pipe 103, and the lower end of the vessel body 101 is provided with a lower discharge valve 104 flush with the bottom surface of the vessel body 101; an auxiliary stirring component 2, comprising a dissolution stirring motor 201 fixed at the center of the top surface of the vessel body 101, wherein the lower end of the dissolution stirring motor 201 is connected to a multi-segment stirring rod 202, wherein the multi-segment stirring rod 202 is provided with a hollow drum 203 at a position corresponding to the inner wall of the top of the vessel body 101, the hollow drum 203 is connected to an external vent pipe 204, and the multi-segment stirring rod 202 is extended after the external vent pipe 204 is vented; and a lower crushing structure 3, comprising a component disposed in the vessel body 101. The grinding frame 301 is located at the bottom of the interior. The bottom of the grinding frame 301 is attached to the vessel body 101. A docking seat 302 is provided in the middle of the grinding frame 301. The multi-segment stirring rod 202 is extended and connected to the docking seat 302, driving the grinding frame 301 to rotate along the bottom of the vessel body 101. The conductive limiting structure 4 includes a first conductive member 401 provided on the inner wall of the vessel body 101. A second conductive member 402 is movably installed on the first conductive member 401. A mating member 403 is provided on the side of the second conductive member 402 near the central axis of the vessel body 101. When the grinding frame 301 rotates, the outer edge of the grinding frame 301 extends outward and is embedded in the mating member 403, so that the entire grinding frame 301 can rotate along the first conductive member 401 through the second conductive member 402.

[0037] A heating jacket is also provided in the reactor body 101. The temperature of the heating jacket is controlled at 40-50℃. Crude lithium difluorophosphate is added to DME solvent at a solid-liquid ratio of 1:3 to 1:5. The stirring speed is controlled at 80-100 r / min. The total stirring time is 2-3 h. Inert gas is introduced through the external vent pipe 204 during the last 15 min of the stirring time.

[0038] The dissolution reactions in this embodiment are all carried out in a sealed environment with inert gas to avoid interference from external oxygen and moisture.

[0039] Since crude lithium difluorophosphate contains some hydrogen fluoride, all metal parts in this embodiment have been treated with anti-corrosion measures to prevent corrosion during use.

[0040] In the later stages of dissolution in existing technologies, some dissolved substances precipitated at the bottom are far from the dissolution area and are difficult to completely dissolve by their own and the solvent's dissolution effect at the end of the reaction. They are carried to the next-stage filtration area along with the insoluble matter and are intercepted and filtered, resulting in the loss of some useful substances in lithium difluorophosphate and thus reducing the overall utilization rate. Therefore, this embodiment uses a lower grinding structure 3 to extend and connect the multi-segment stirring rod 202 to the docking seat 302 of the grinding frame 301 when the conventional stirring time ends. This allows the multi-segment stirring rod 202 to rotate, thereby driving the entire grinding frame 301 to rotate and grinding the remaining dissolved substances mixed with insoluble matter at the bottom of the entire reactor 101, thus promoting the overall reaction.

[0041] The multi-segment stirring rod 202 needs to perform the function of connecting the grinding frame 301. Therefore, in this embodiment, the multi-segment stirring rod 202 includes a porous connecting pipe 2021 connected to the dissolving stirring motor 201. The lower end of the porous connecting pipe 2021 is connected to a thickening pipe 2022, and the lower end of the thickening pipe 2022 is provided with an elastic pressure pipe 2023. The projected position of the elastic pressure pipe 2023 is directly opposite to the mating part 403. The multi-segment stirring rod 202 is divided into three segments: the porous connecting pipe 2021 that allows air to pass through, the thickening pipe 2022 that performs the main stirring function, and the elastic pressure pipe 2023 that is movably engaged with the grinding frame 301. When inert gas is introduced into the porous connecting pipe 2021, the elastic pressure pipe 2023 can pop out and engage with the grinding frame 301, driving the grinding frame 301 to rotate. Since inert gas is introduced, there is no need to worry about safety hazards even if gas leakage occurs.

[0042] To ensure that the grinding frame 301 is driven only after dissolution, thereby improving the efficiency of the initial stirring process, the elastic pressure tube 2023 in this embodiment includes an elastic seat 20231 located at the bottom of the inner cavity of the thickened tube 2022. The lower end of the elastic seat 20231 is connected to a pressing tube 23232, which penetrates the bottom surface of the thickened tube 2022. The elastic seat 20231, which can move up and down, is provided in the elastic pressure tube 2023. When the elastic seat 20231 is compressed by the inert gas, it falls down, pushing out the pressing tube 23232 and engaging it with the docking seat 302. After the inert gas is depressurized, the elastic seat 20231 returns to its original position, causing the pressing tube 23232 to return to its original position and separate from the docking seat 302.

[0043] During the gas intake process of the porous connecting pipe 2021, it is necessary to ensure the guiding effect of the inert gas. Although its overflow into the vessel body 101 will not affect the dissolution process, it will affect the fit between the pressure pipe 23232 and the docking seat 302. Therefore, the hollow drum 203 in this embodiment includes a hollow chamber 2031 disposed at the lower end of the upper cover of the vessel body 101. The hollow chamber 2031 is connected to the external vent pipe 204 through the external conduit 2032, and the hollow chamber 2031 is connected to the connecting hole of the porous connecting pipe 2021. Through the hollow drum 203, a guide is formed on the outside of the porous connecting pipe 2021, so that the gas intake process can only occur in the internal area of ​​the hollow drum 203. Through the guidance of the small space, not only can the pressure of the gas intake be guaranteed, but the possibility of leakage can also be reduced.

[0044] When grinding the vessel body 101, the grinding frame 301 needs to ensure not only the grinding effect but also its own stability. Therefore, the grinding frame 301 in this embodiment includes a grinding frame body 3011 that is movably fitted to the bottom of the vessel body 101. An elastic metal ring 3012 is provided on the outer edge of the grinding frame body 3011. The outer side of the elastic metal ring 3012 is movably fitted with the mating part 403, so that the grinding frame body 3011 contacts and grinds the bottom of the vessel body 101, while the elastic metal ring 3012 and the mating part 403 are linked, thereby achieving a stable grinding effect.

[0045] During the grinding process, the grinding frame body 3011 grinds not only the bottom but the entire bottom area. In this embodiment, the grinding frame body 3011 includes a small grinding disc 30111 located on the top surface of the lower discharge valve 104 and a large grinding disc 30112 located outside the conduction limiting structure 4. The small grinding disc 30111 and the large grinding disc 30112 are connected by several grinding arms 30113. The small grinding disc 30111, the large grinding disc 30112 and the several grinding arms 30113 form a grinding surface covering the entire bottom surface of the vessel body 101, thereby ensuring that the tiny soluble substances at the end of the dissolution stage can completely react with the solvent.

[0046] If there are particles moving with the grinding arm 30113, the grinding arm 30113 in this embodiment is an arc-shaped structure that fits the curvature of the bottom surface of the vessel body 101. Several fins are provided on the outer side of the grinding arm 30113. The soluble matter between adjacent grinding arms 30113 can be lifted by the fins. Several fins are also provided on the outer side of the grinding arm 30113. The fins will fan as the grinding arm 30113 rotates, thereby lifting the soluble matter between the two grinding arms 30113 upwards, thereby improving the dissolution efficiency.

[0047] During the entire grinding process of the grinding frame 301, although the shape of the grinding frame 301 fits the bottom area of ​​the vessel body 101, if it is simultaneously rubbed and stuck by a large amount of insoluble matter during the long-term reciprocating rotation, it may deviate. Therefore, the present invention uses the set conductive limiting structure 4 to allow the grinding frame 301 to form a linkage with the mating part 403 on the second conductive part 402 when rotating, driving the second conductive part 402 to rotate along the first conductive part 401, thereby ensuring the stability of the grinding frame 301. Furthermore, since the first conductive part 401 and the second conductive part 402 themselves have a conductive effect, soluble or insoluble matter will not be deposited, and the normal reaction will not be affected.

[0048] While the first conductive element 401 and the second conductive element 402 are connected and guided, if particulate matter accumulates, not only will rotation be easily obstructed, but insoluble matter may also get stuck at that position and be unable to drain. Therefore, in this embodiment, the first conductive element 401 is an annular band 4011 connected to the inner wall of the vessel body 101. The middle part of the annular band 4011 is recessed inward and forms several external through holes 4012. The second conductive element 402 is a zigzag band 4021 embedded in the recessed area of ​​the annular band 4011. The recessed area of ​​the Z-shaped band 4021 is provided with several internal through holes 4022. The first guide member 401 and the second guide member 402 are not only configured as annular band 4011 and Z-shaped band 4021 that are recessed and matched with each other, but also have external through holes 4012 and internal through holes 4022 in the annular band 4011 and Z-shaped band 4021. So that when the annular band 4011 and Z-shaped band 4021 are not in motion, particles can pass through the through holes smoothly and are not easily blocked by the guide members.

[0049] The mating component 403 is pre-installed during its engagement with the elastic metal ring 3012. Specifically, the elastic metal ring 3012 includes an elastic arc ring 30121 connected to the top of the large grinding disc 30112. The outer side of the elastic arc ring 30121 is integrally formed with several clamping grooves 30122. The clamping grooves 30122 engage with the mating component 403. The mating component 403 consists of several ribs located inside the Z-shaped belt 4021. The ribs are movably engaged with the grinding frame 301. The faster the grinding frame 301 rotates, the smaller the distance between it and the ribs, meaning that the clamping grooves 30122 are pre-clamped with the ribs. After the elastic metal ring 3012 rotates with the grinding frame body 3011, the elastic arc ring 30121 expands and deforms outward, thereby making the engagement between the clamping grooves 30122 and the ribs tighter and preventing disengagement after the rotation speed increases.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A device for dissolving crude lithium difluorophosphate, characterized in that, include: The dissolving vessel (1) includes a vessel body (101) for holding liquid. The top of the vessel body (101) is provided with a crude product feed chamber column (102) and a solvent feed chamber pipe (103). The lower end of the vessel body (101) is provided with a lower discharge valve (104) that is flush with the bottom surface of the vessel body (101). The auxiliary stirring component (2) includes a dissolving stirring motor (201) fixed at the center of the top surface of the vessel body (101). The lower end of the dissolving stirring motor (201) is connected to a multi-segment stirring rod (202). The multi-segment stirring rod (202) is provided with a hollow drum (203) at the position corresponding to the inner wall of the top of the vessel body (101). The hollow drum (203) is connected to an external vent pipe (204). After the external vent pipe (204) is vented, the multi-segment stirring rod (202) is extended. The lower grinding structure (3) includes a grinding frame (301) disposed at the bottom of the inside of the vessel body (101). The bottom of the grinding frame (301) is attached to the vessel body (101). A docking seat (302) is provided in the middle of the grinding frame (301). The multi-segment stirring rod (202) is extended and connected to the docking seat (302) and drives the grinding frame (301) to rotate along the bottom of the vessel body (101). The guiding and limiting structure (4) includes a first guiding component (401) disposed on the inner wall of the vessel body (101), a second guiding component (402) is movably mounted on the first guiding component (401), and a mating component (403) is disposed on the side of the second guiding component (402) near the central axis of the vessel body (101). When the grinding frame (301) rotates, the outer edge of the grinding frame (301) extends outward and is embedded in the mating component (403), so that the entire grinding frame (301) can rotate along the first guiding component (401) through the second guiding component (402).

2. The lithium difluorophosphate crude dissolution equipment according to claim 1, characterized in that, The multi-segment stirring rod (202) includes a porous connecting pipe (2021) connected to the dissolving stirring motor (201). The lower end of the porous connecting pipe (2021) is connected to a thickening pipe (2022). The lower end of the thickening pipe (2022) is provided with an elastic pressure pipe (2023). The projected position of the elastic pressure pipe (2023) is directly opposite to the mating part (403).

3. The lithium difluorophosphate crude dissolution equipment according to claim 2, characterized in that, The elastic pressure tube (2023) includes an elastic seat (20231) located at the bottom of the inner cavity of the thickened tube (2022). The lower end of the elastic seat (20231) is connected to a pressure tube (23232), which penetrates the bottom surface of the thickened tube (2022).

4. The lithium difluorophosphate crude dissolution equipment according to claim 3, characterized in that, The hollow drum (203) includes a hollow chamber (2031) disposed at the lower end of the upper cover of the vessel body (101). The hollow chamber (2031) is connected to the external vent pipe (204) through an external conduit (2032), and the hollow chamber (2031) is connected to the communication hole of the porous connecting pipe (2021).

5. The lithium difluorophosphate crude dissolution equipment according to claim 1, characterized in that, The grinding frame (301) includes a grinding frame body (3011) that is movably fitted to the bottom of the inside of the vessel body (101). An elastic metal ring (3012) is provided on the outer edge of the grinding frame body (3011), and the outer side of the elastic metal ring (3012) is movably fitted with the mating part (403).

6. The lithium difluorophosphate crude dissolution equipment according to claim 5, characterized in that, The main body of the grinding frame (3011) includes a small grinding disc (30111) located on the top surface of the lower discharge valve (104) and a large grinding disc (30112) located outside the conduction limiting structure (4). The small grinding disc (30111) and the large grinding disc (30112) are connected by several grinding arms (30113).

7. The lithium difluorophosphate crude dissolution equipment according to claim 6, characterized in that, The grinding arm (30113) is an arc-shaped structure that fits the curvature of the bottom surface of the vessel body (101). Several fins are provided on the outer side of the grinding arm (30113), and the soluble substances between adjacent grinding arms (30113) can be lifted by the fins.

8. The lithium difluorophosphate crude dissolution equipment according to claim 5, characterized in that, The elastic metal ring (3012) includes an elastic arc ring (30121) connected to the top of the large grinding disc (30112). The outer side of the elastic arc ring (30121) is integrally formed with several clamping grooves (30122), and the clamping grooves (30122) cooperate with the mating parts (403).

9. The lithium difluorophosphate crude dissolution equipment according to claim 1, characterized in that, The first conductive element (401) is an annular strip (4011) connected to the inner wall of the vessel body (101). The middle part of the annular strip (4011) is recessed inward and forms a plurality of external conductive holes (4012). The second conductive element (402) is a zigzag strip (4021) embedded in the recessed area of ​​the annular strip (4011). The recessed area of ​​the zigzag strip (4021) is provided with a plurality of internal conductive holes (4022).

10. The lithium difluorophosphate crude dissolution equipment according to claim 9, characterized in that, The fitting component (403) consists of several ribs located inside the zigzag band (4021). The ribs are movably fitted with the grinding frame (301), and the gap between the grinding frame (301) and the ribs is smaller as the grinding frame (301) rotates faster.

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