A fully automatic lithium hexafluorophosphate crystallizer

Abstract

The application discloses a full-automatic lithium hexafluorophosphate crystallizer, which comprises a reaction kettle, a feeding pipe and a temperature control system, the reaction kettle is a cylindrical reaction kettle, the bottom of the reaction kettle is provided with a collecting groove, the feeding pipe is at least partially inserted into the reaction kettle, a hopper is arranged on the feeding pipe, the hopper is arranged in the reaction kettle, a filter screen is arranged on the hopper, the filter screen is a louver structure comprising blades and a frame, the frame is obliquely arranged, the cross section of the blade is in the shape of a truncated cone, the temperature control system comprises a liquid inlet pipe and a temperature control pipe, the liquid inlet pipe is arranged on the outer wall of the reaction kettle, the temperature control pipe is spirally arranged on the outer wall of the reaction kettle, the liquid inlet pipe is provided with a liquid inlet and a liquid outlet, and the two ends of the temperature control pipe are communicated with the liquid inlet and the liquid outlet respectively. The full-automatic lithium hexafluorophosphate crystallizer can prevent the crystal from adhering to the filter screen, so that the filter screen is blocked and the discharging efficiency is affected.

Description

Technical Field

[0001] This invention relates to the field of lithium hexafluorophosphate preparation technology, and in particular to a fully automated lithium hexafluorophosphate crystallizer. Background Technology

[0002] Lithium-ion batteries possess outstanding advantages such as high operating voltage, high energy density (light weight), low self-discharge rate, no memory effect, long cycle life, and no pollution. These unparalleled advantages have led to their rapid expansion into many fields, with widespread applications in well-known products such as mobile phones, laptops, small camcorders, and electric vehicles. With the industrialization of electric vehicles, their usage is bound to increase even further. Applications demonstrate that lithium-ion batteries are an ideal small, green power source.

[0003] Electrolyte is one of the four key materials in lithium-ion batteries, often referred to as the "blood" of the battery. It plays a crucial role in conducting electrons between the positive and negative electrodes, ensuring the high voltage and high specific energy of the lithium-ion battery. Electrolyte is generally prepared by mixing high-purity organic solvents, lithium electrolyte salts, and necessary additives in specific proportions under certain conditions.

[0004] Lithium hexafluorophosphate (LiPF6) is a key raw material for lithium-ion battery electrolytes. Its production technology involves requirements related to low temperature, high temperature, vacuum, corrosion resistance, safety, and environmental protection, as disclosed in patents such as CN 106430255A and CN 105845931A. The equipment requirements are high, and the processes are complex. With the continuous improvement of lithium-ion battery manufacturing technology and production volume in my country, the demand for LiPF6 is also increasing. Therefore, achieving continuous production of LiPF6 and improving its yield and quality are key factors in enhancing enterprises' market competitiveness and resource utilization. Industrial synthesis methods for LiPF6 include wet, dry, and solvent methods. The solvent method requires crystallization and drying of the LiPF6 mother liquor to obtain the final product. A crystallizer is needed during the crystallization process.

[0005] Chinese patent CN201920612176.0 proposes a fully enclosed automatic loading and unloading mechanism for a lithium hexafluorophosphate crystallizer. This device can continuously feed materials, realizing the large-scale production of lithium hexafluorophosphate. However, during the crystallization process, crystals may adhere to the filter screen, causing filter screen blockage and reducing output efficiency. Summary of the Invention

[0006] The present invention aims to provide a fully automatic lithium hexafluorophosphate crystallizer to solve the problem of crystals adhering to the filter screen of the crystallizer.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A fully automatic lithium hexafluorophosphate crystallizer includes: a reaction vessel, a feed pipe, and a temperature control system.

[0009] The reactor is a cylindrical reactor with a collection tank at the bottom;

[0010] The feed pipe extends at least partially into the reactor. The feed pipe is equipped with a hopper located inside the reactor. The hopper is equipped with a filter screen, which is a louvered structure comprising blades and a frame. The frame is obliquely distributed, and the blades have a truncated conical cross-section.

[0011] The temperature control system includes an inlet pipe and a temperature control tube. The inlet pipe is located on the outer wall of the reactor, and the temperature control tube is spirally distributed on the outer wall of the reactor. The inlet pipe has an inlet and an outlet, and the two ends of the temperature control tube are respectively connected to the inlet and the outlet.

[0012] In some embodiments, there are multiple filters, with two filters forming a group, and each group of filters forming an inverted "V" shape.

[0013] In some embodiments, multiple sets of the filters are spaced apart in the vertical direction.

[0014] In some embodiments, the filter screen is provided with a rotating mechanism, the rotating mechanism including a first connecting rod and a first driven rod, the first connecting rod being slidably engaged in the hopper, the first driven rod being rotatably connected in the hopper, the first connecting rod being rotatably connected to the first driven rod, the blade being rotatably engaged with the frame, and the end near the first driven rod being rotatably connected to the first driven rod, the first connecting rod moving up and down, causing the first driven rod to swing up and down, so that the blade rotates relative to the frame.

[0015] In some embodiments, the feed pipe includes an outer pipe and a spiral inner pipe. The spiral inner pipe is a first pipeline, and the outer pipe and the spiral inner pipe cooperate to form a spiral second pipeline. The first pipeline connects the outside and the inside of the reactor and is used to feed mother liquor into the reactor. The second pipeline is provided with a nitrogen inlet, a hopper connection port, an exhaust gas outlet, and a discharge port. The nitrogen inlet, the exhaust gas outlet, and the discharge port are all located outside the reactor. The hopper connection port is used to connect the second pipeline and the hopper. The spiral inner pipe is rotatably engaged with the outer pipe, and the spiral inner pipe rotates relative to the outer pipe.

[0016] In some embodiments, the second pipeline is provided with a spiral seal at the nitrogen inlet.

[0017] In some embodiments, the outer tube is rotatably coupled to the reactor, and the reactor rotates relative to the feed tube.

[0018] In some embodiments, the crystallizer is equipped with multiple temperature sensors.

[0019] In some embodiments, the reactor is provided with pile foundation rollers, which are located above the collection tank and are spaced apart in the horizontal direction.

[0020] The beneficial effects of this invention are as follows:

[0021] The fully automatic lithium hexafluorophosphate crystallizer of the present invention is equipped with a filter screen with a louver structure. When the crystals adhere to the filter screen, the gap between the blades can be changed by rotating the blades. The crystals can also be pushed off, and the already cracked crystals can be broken and precipitated through the filter screen, thereby increasing the discharge speed.

[0022] The fully automatic lithium hexafluorophosphate crystallizer of the present invention combines the condensation system and the heating system into a temperature control system, which simplifies the operation process.

[0023] The fully automatic lithium hexafluorophosphate crystallizer feed pipe of this invention utilizes the three-way principle to achieve automated and unmanned feeding of mother liquor and nitrogen, avoiding contact with toxic substances by workers and improving safety. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a fully automated lithium hexafluorophosphate crystallizer according to an embodiment of the present invention;

[0025] Figure 2 This is a cross-sectional view of a fully automated lithium hexafluorophosphate crystallizer according to an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the hopper according to an embodiment of the present invention;

[0027] Figure 4 This is a cross-sectional view of the hopper in Embodiment 1 of the present invention;

[0028] Figure 5 This is a cross-sectional view of the hopper in Embodiment 2 of the present invention. Detailed Implementation

[0029] The invention will now be further described with reference to the accompanying drawings.

[0030] The fully automatic lithium hexafluorophosphate crystallizer of this invention includes: a reaction vessel 1, a feed pipe, and a temperature control system.

[0031] Specifically, such as Figure 1 , Figure 2 As shown, the reactor 1 is cylindrical, with a collection tank 6 at its bottom. Above the collection tank 6 inside the reactor 1, there are multiple pile foundation rollers 8 that are spaced apart along the horizontal direction.

[0032] One end of the feed pipe is located outside the reactor 1, and the other end extends into the reactor 1, with a hopper 4 at the end. The feed pipe includes an outer pipe 22 and a spiral inner pipe 21, which are coaxially distributed with the outer pipe 22. The inner wall of the spiral inner pipe 21 forms a first pipeline, and a spiral second pipeline is formed between the spiral inner pipe 21 and the outer pipe 22. The first pipeline has an inlet A and an outlet B, with outlet B connecting to the inside of the reactor 1. The mother liquor can be fed into the reactor 1 through the first pipeline from inlet A to outlet B. The second pipeline is connected to a nitrogen inlet 23, a hopper connection port 24, an exhaust gas outlet 25, and a discharge port 26. The nitrogen inlet 23 and the exhaust gas outlet 25 are located at the upper end of the outer pipe 22 outside the reactor 1, spaced apart, with the exhaust gas outlet 25 close to the reactor 1. The discharge port 26 is located at the lower end of the outer pipe 22 between the nitrogen inlet 23 and the exhaust gas outlet 25. A spiral seal 7 is provided at the right end of the nitrogen inlet 23. The spiral seal 7 rotates in the opposite direction to the spiral inner tube 21, thus sealing the second pipeline. The outer tube 22 is rotatably fitted with the reactor 1, allowing the reactor 1 to rotate relative to the outer tube 22 around its axis. The spiral inner tube 21 is also rotatably fitted with the outer tube 22, allowing the spiral inner tube to rotate relative to the outer tube 22.

[0033] The temperature control system includes an inlet pipe 31 and a temperature control tube 32. The inlet pipe 31 is located on the side wall of the reactor 1, and the temperature control tube 32 is spirally distributed on the outer wall of the reactor 1. The inlet pipe 31 has an inlet 33 and an outlet 34, and the two ends of the temperature control tube 32 are connected to the inlet 33 and the outlet 34, respectively. Multiple temperature sensors are installed on the crystallizer to monitor the temperature of the reactor 1.

[0034] Example 1:

[0035] like Figure 3 , 4 As shown, the hopper 4 is equipped with a filter screen 5, which is a louvered structure including a frame 51 and blades 52. The two filter screens 5 are arranged in an inverted "V" shape. The blades 52 have a truncated cone cross-section. A rotating mechanism is provided between the blades 52 and the frame 51. The rotating mechanism includes a first connecting rod 53 and a first driven rod 54. The first connecting rod 53 slides on the inner wall of the hopper 4 and can move vertically up and down. The bottom end of the first driven rod 54 is rotatably connected to the inner wall of the hopper 4 via a pivot. The top end of the first connecting rod 53 is rotatably connected to the top end of the first driven rod 54. Both ends of the blades 52 are rotatably connected to the frame 51 via pivots, and a connecting plate 55 extends from the end closest to the first driven rod 54. The blades 52 are rotatably connected to the first driven rod 54 via the connecting plate 55 and the pivot. When the first connecting rod 53 moves up or down, it drives the first driven rod 54 to swing up and down, thereby causing the blades 52 to rotate counterclockwise or clockwise relative to the frame 51, thus changing the gap between the blades 52. It prevents crystals from adhering to filter screen 5 and can also break up already cracked crystals.

[0036] Example 2:

[0037] like Figure 5 As shown, in the fully automatic lithium hexafluorophosphate crystallizer of this embodiment, the hopper 4 is provided with a double-layer filter screen 5. The two layers of filter screen 5 have the same structure and are both provided with a rotating mechanism. The rotating mechanism can drive the blades 52 to rotate. Some crystals will be embedded in the upper filter screen 5 when they hit it. Even if the blades 52 are rotated, the crystals cannot fall off. At this time, the crystals embedded in the gaps between the blades 52 of the upper filter screen 5 can be pushed out by rotating the blades 52 of the lower filter screen 5.

[0038] The working principle of the fully automatic lithium hexafluorophosphate crystallizer in this embodiment of the invention is as follows:

[0039] Before introducing the liquid, start the reactor 1 to rotate clockwise at a speed of 1 r / min, open the valve of inlet A, and start feeding the mother liquor into the reactor 1. At the same time, open the valve of exhaust outlet 25 to reduce the pressure inside the reactor 1.

[0040] After crystallization and liquid inlet are completed, close the valves of inlet A and exhaust outlet 25. The reactor 1 stops rotating. Introduce refrigerant into the temperature control pipe 32 through the liquid inlet pipe 31. Adjust the refrigerant pressure to above 0.5 MPa and maintain the temperature inside the reactor 1 at -50 degrees Celsius. Then wait for crystallization to complete.

[0041] After crushing, drying, and crystallization, close the valves at the inlet 33 and outlet 34, open the nitrogen inlet 23 valve, and adjust the pressure inside reactor 1 to 0.15 MPa. Inject heat medium into the temperature control pipe 32 through the inlet pipe 31 to maintain the temperature of reactor 1 at 30 degrees Celsius and the heat medium pressure above 0.3 MPa. Then, open the valves at the nitrogen inlet 23 and exhaust outlet 25, and adjust the pressure inside reactor 1 to less than or equal to 0.3 MPa. Rotate reactor 1 clockwise at a speed of 1 r / min. At this time, the residual acid in reactor 1 evaporates to form acid gas, which is then expelled from reactor 1 through the second pipeline and exhaust outlet 25 by the nitrogen gas. During crystallization, the height difference generated by the rotation of reactor 1 is used to crush the crystals using the pile roller 8. After completion, close the valves at the nitrogen inlet 23 and exhaust outlet 25.

[0042] Discharge: Open the valve of nitrogen inlet 23 and introduce nitrogen into reactor 1. When the pressure in reactor 1 rises to 0.1 MPa, open the valve at outlet 26. Rotate the spiral inner tube 21 at a speed of 30 r / min or more, and rotate reactor 1 counterclockwise at a speed of 1-2 r / min. At this time, the crystals in reactor 1 fall into hopper 4 due to gravity when the collection tank 6 rotates above hopper 4. The crystals stuck on the filter screen 5 can be broken by rotating blades 52 and fall into hopper 4. After falling into hopper 4, the crystals enter the second pipeline through hopper connection port 24 and are discharged from outlet 26 under the push of spiral inner tube 21.

[0043] The fully automatic lithium hexafluorophosphate crystallizer of this invention can prevent crystals from adhering to the filter screen, thereby clogging the filter screen and affecting the discharge efficiency.

[0044] This embodiment does not impose any limitation on the shape, material, structure, etc. of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0045] In the description of this invention, it should be understood that the terms "clockwise," "counterclockwise," "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used for the convenience of describing this invention and simplifying the description, and do not 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 limiting the scope of protection of this invention.

[0046] 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.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fully automatic lithium hexafluorophosphate crystallizer, characterized in that, include: The reaction vessel is a cylindrical reaction vessel with a collection tank at its bottom; A feed pipe extends at least partially into the reactor. A hopper is mounted on the feed pipe and located inside the reactor. A filter screen, a louvered structure comprising blades and a frame, is mounted on the hopper. The frame is obliquely distributed, and the blades have a truncated conical cross-section. A rotating mechanism is mounted on the filter screen. The rotating mechanism includes a first connecting rod and a first driven rod. The first connecting rod slides within the hopper, and the first driven rod is rotatably connected within the hopper. The first connecting rod and the first driven rod are rotatably connected. The blades are rotatably engaged with the frame, and one end near the first driven rod is rotatably connected to the first driven rod. The first connecting rod moves up and down, causing the first driven rod to swing up and down, thus rotating the blades relative to the frame. This changes the gap between the blades, preventing crystals from adhering to the filter screen and also breaking up already cracked crystals. A temperature control system includes an inlet pipe and a temperature control tube. The inlet pipe is located on the outer wall of the reactor, and the temperature control tube is spirally distributed on the outer wall of the reactor. The inlet pipe has an inlet and an outlet, and the two ends of the temperature control tube are respectively connected to the inlet and the outlet.

2. The fully automatic lithium hexafluorophosphate crystallizer according to claim 1, characterized in that, There are multiple filters, with two filters forming a group, and each group of filters forming an inverted "V" shape.

3. The fully automatic lithium hexafluorophosphate crystallizer according to claim 2, characterized in that, The multiple sets of filters are spaced apart in the vertical direction.

4. The fully automatic lithium hexafluorophosphate crystallizer according to claim 1, characterized in that, The feed pipe includes an outer pipe and a spiral inner pipe. The spiral inner pipe is a first pipe, and the outer pipe and the spiral inner pipe cooperate to form a spiral second pipe. The first pipe connects the outside and the inside of the reactor and is used to feed the mother liquor into the reactor. The second pipe is provided with a nitrogen inlet, a hopper connection port, an exhaust gas outlet, and a discharge port. The nitrogen inlet, the exhaust gas outlet, and the discharge port are all located outside the reactor. The hopper connection port is used to connect the second pipe and the hopper. The spiral inner pipe is rotatably engaged with the outer pipe and rotates relative to the outer pipe.

5. The fully automatic lithium hexafluorophosphate crystallizer according to claim 4, characterized in that, The second pipeline is equipped with a spiral seal at the nitrogen inlet.

6. The fully automatic lithium hexafluorophosphate crystallizer according to claim 4, characterized in that, The outer tube is rotatably fitted to the reactor, and the reactor rotates relative to the feed pipe.

7. The fully automatic lithium hexafluorophosphate crystallizer according to claim 1, characterized in that, The crystallizer is equipped with multiple temperature sensors.

8. The fully automatic lithium hexafluorophosphate crystallizer according to claim 1, characterized in that, The reactor is equipped with pile foundation rollers, which are located above the collection tank and are spaced apart in the horizontal direction.

Images