A lithium hexafluorophosphate crystal solid-liquid separation and drying device

Abstract

The present invention belongs to the field of lithium hexafluorophosphate production, and specifically relates to a lithium hexafluorophosphate crystal solid-liquid separation and drying device, comprising a frame and a fixed outer cylinder, wherein a rotatable filter rotor assembly is coaxially sleeved inside the outer cylinder; the filter rotor assembly comprises a rotor main shaft, a filter screen cylinder and a spiral blade group, a drive motor is arranged at the rear of the outer cylinder, and the rear end of the rotor main shaft is connected to the drive motor by transmission; an annular feeding port is arranged at the front end of the filter screen cylinder, a discharge port is arranged at the rear end of the filter screen cylinder, a feed pipe is connected to the upper side of the front end of the outer cylinder, the discharge end of the feed pipe extends into the feeding port, a discharge port is arranged at the lower side of the rear end of the outer cylinder, a liquid outlet is arranged at the lower side of the front end of the outer cylinder, an air outlet is arranged at the upper side of the rear end of the outer cylinder, and a drying and heating interlayer is sleeved on the outer side of the rear part of the outer cylinder. The device significantly reduces the wear of lithium hexafluorophosphate crystals and separation equipment, prolongs the life of the equipment, optimizes the drying process, and improves the production efficiency and safety of the solid-liquid separation and drying processes.

Description

Technical Field

[0001] The invention belongs to the field of lithium hexafluorophosphate production, and in particular relates to a lithium hexafluorophosphate crystal solid-liquid separation and drying device. Background Art

[0002] Lithium hexafluorophosphate is an important raw material for lithium batteries, but due to its dielectric properties, it will undergo a deterioration reaction in the air, and the entire production process requires that it cannot come into contact with air. Lithium hexafluorophosphate is toxic and highly corrosive, and skin contact should be avoided during the production process. The common production process of lithium hexafluorophosphate is to dissolve lithium salt in anhydrous hydrofluoric acid, then introduce phosphorus pentafluoride gas to react and produce lithium hexafluorophosphate crystals, and then separate and dry to obtain lithium hexafluorophosphate products. The current solid-liquid separation of lithium hexafluorophosphate crystals uses a horizontal spiral centrifugal separator. During the separation process, there is strong friction between the lithium hexafluorophosphate crystals and the spiral main shaft, spiral blades and horizontal cylinder. The separated hydrofluoric acid is highly corrosive and will cause accelerated wear of the internal contact parts of the separator, seriously affecting the normal service life of the separator. In addition, metal particles generated by the friction contact parts of the separator may enter the lithium hexafluorophosphate crystals and may cause excessive metal content, which has an adverse effect on the performance of lithium battery products. Moreover, after the solid-liquid separation of the lithium hexafluorophosphate crystals, they must be dried separately. The separation and drying efficiency is low, which affects the overall production efficiency of lithium hexafluorophosphate. Phosphorus pentafluoride gas is prone to leakage between the separation process and the drying process. Phosphorus pentachloride can irritate the conjunctiva, throat and other trachea of ​​the human body, which can cause diseases such as bronchitis, pneumonia and pulmonary edema, posing a serious threat to the health of the staff. Summary of the invention

[0003] In view of the above situation, the present invention provides a lithium hexafluorophosphate crystal solid-liquid separation and drying device, which can significantly reduce the friction and wear between the lithium hexafluorophosphate crystals and the separation device, and optimizes the drying process, which helps to improve the production efficiency and work safety of lithium hexafluorophosphate.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A solid-liquid separation and drying device for lithium hexafluorophosphate crystals, comprising a frame and an outer cylinder fixed on the frame, wherein the two ends of the outer cylinder are respectively sealed with a front cover and a rear cover, and a rotatable filter rotor assembly is coaxially sleeved inside the outer cylinder; the filter rotor assembly comprises a rotor main shaft, a filter screen cylinder and a spiral leaf group, wherein the spiral leaf group is fixedly connected to the outer side of the rotor main shaft, the filter screen cylinder is fixedly sleeved on the outer periphery of the spiral leaf group, the two ends of the rotor main shaft are rotatably connected to the front and rear end covers of the outer cylinder, and a ... A driving motor is provided, and the rear end of the rotor main shaft is drivingly connected to the driving motor; an annular feeding port is arranged at the front end of the filter screen cylinder, a discharge port is arranged at the rear end of the filter screen cylinder, a feed pipe is connected to the upper side of the front end of the outer cylinder body, the discharge end of the feed pipe extends into the feeding port, a discharge port is arranged at the lower side of the rear end of the outer cylinder body, a liquid outlet is arranged at the lower side of the front end of the outer cylinder body, an air outlet is arranged at the upper side of the rear end of the outer cylinder body, a heating interlayer is sleeved on the outer side of the rear part of the outer cylinder body, a heat medium inlet is arranged at the front end of the heating interlayer, and a heat medium outlet is arranged at the rear end of the heating interlayer.

[0006] Furthermore, an observation hole is arranged above the front end of the outer cylinder, and a sealing plate is arranged on the observation hole. The sealing plate is connected by a flange, and a tetrafluoroethylene sealing gasket is arranged in the middle of the flange. A plurality of spare interfaces are also arranged on the sealing plate and the side wall of the outer cylinder.

[0007] Furthermore, a funnel-shaped receiving hopper is connected below the discharge port, and a drop port is provided at the bottom of the receiving hopper. The lithium hexafluorophosphate crystal material drops from the discharge port of the filter screen cylinder and is collected and discharged through the receiving hopper.

[0008] Furthermore, the front end cover and the rear end cover are respectively connected to the outer cylinder flange through end cover sealing gaskets, and the end cover sealing gaskets are made of polytetrafluoroethylene material, which has good sealing performance and strong corrosion resistance.

[0009] Furthermore, the front end of the rotor main shaft is rotatably connected to the front end cover of the outer cylinder through a sealed bearing; the rear end of the rotor main shaft is rotatably connected to the rear end cover of the outer cylinder through a mechanical seal. The sealed bearing is a bearing assembly, including the bearing itself, which is a tapered roller bearing, sleeved on the front end of the rotor main shaft, and also includes a bearing shell, a bearing end cover, a sealing shell and a labyrinth ring.

[0010] Furthermore, the driving motor is connected to the rotor main shaft through a speed reducer, a driving gear is arranged on the output shaft of the speed reducer, and a driven gear meshing with the driving gear is arranged at the rear end of the rotor main shaft. A motor support is arranged below the driving motor, and the top of the motor support is an elevation support surface adapted to the outer cylinder.

[0011] Furthermore, the outer cylinder is a horizontal cylinder with a low front end and a high rear end and an elevation angle of 4 to 8 degrees. During the process of upward spiral transport of lithium hexafluorophosphate crystals in the filter rotor assembly, the liquid components contained therein are filtered out through the filter screen and flow downward to the liquid outlet. The elevation angle of the outer cylinder is preferably 5 to 6 degrees, which is convenient for the separated hydrofluoric acid liquid to flow out quickly downward and can ensure the reliable transportation of the separated solids.

[0012] Furthermore, the filter screen cylinder is a porous screen cylinder, and the spiral blade group includes spiral blades arranged on the outside of the rotor main shaft, and spiral ribbon blades arranged on the periphery of the spiral blades. On the one hand, it ensures the transportation of lithium hexafluorophosphate crystals, and on the other hand, it also has the function of stirring the lithium hexafluorophosphate crystals. The friction and collision between the crystals themselves also have the effect of breaking up and crushing them.

[0013] Furthermore, the outer cylinder, the rotor main shaft, the filter screen cylinder and the spiral blade group are all made of 316L stainless steel. 316L stainless steel is smooth, has high hardness, strong corrosion resistance and is not easy to wear.

[0014] Furthermore, the heat medium introduced into the heating interlayer is heat-conducting oil, which has good heat transfer effect and energy-saving effect, and the interior of the heating interlayer presents a coil-type heat exchange structure.

[0015] The present invention also includes other components that enable it to be used normally, all of which are conventional means in the art. In addition, devices or components not limited in the present invention all adopt the existing technology in the art.

[0016] The beneficial effects of the present invention are as follows:

[0017] The invention provides a lithium hexafluorophosphate crystal solid-liquid separation and drying device, which reduces the friction between the material and the device, has strong corrosion resistance, can significantly reduce the degree of wear of the device, is beneficial to prolonging the service life of the device, avoids the problem of excessive metal content caused in the lithium hexafluorophosphate crystal solid-liquid separation process, and is beneficial to ensuring the performance and quality of lithium battery products; the device integrates solid-liquid separation and heating and drying in one, optimizes the drying process, avoids the material dumping operation between the solid-liquid separation and drying processes, reduces the risk of phosphorus pentafluoride gas leakage, and has good sealing performance, which is beneficial to improving the overall production efficiency and work safety of lithium hexafluorophosphate, and is beneficial to protecting the health of personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of the solid-liquid separation and drying device for lithium hexafluorophosphate crystals in the embodiment.

[0019] Figure 2 for Figure 1 Schematic diagram of the top view structure.

[0020] Figure 3 for Figure 1Schematic diagram of the left view structure.

[0021] Figure 4 for Figure 1 Schematic diagram of the structure of the filter rotor assembly.

[0022] Figure 5 for Figure 1 Schematic diagram of the cross-sectional structure of the inner and outer cylinders.

[0023] Figure 6 for Figure 1 Schematic diagram of the cross-sectional structure of the middle bearing assembly. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments.

[0025] It should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "front", "back", "inside", "outside", "middle", etc. are based on the drawings and are for the convenience of description only.

[0026] Example

[0027] like Figure 1-6 As shown, a solid-liquid separation and drying device for lithium hexafluorophosphate crystals comprises a frame 1 and an outer cylinder 2 fixed on the frame, the two ends of the outer cylinder are respectively sealed with a front cover 3 and a rear cover 4, a rotatable filter rotor assembly is coaxially sleeved inside the outer cylinder; the filter rotor assembly comprises a rotor main shaft 5, a filter screen cylinder 6 and a spiral leaf group 7, the spiral leaf group is fixedly connected to the outer side of the rotor main shaft, the filter screen cylinder is fixedly sleeved on the periphery of the spiral leaf group, the two ends of the rotor main shaft are rotatably connected to the front and rear end covers of the outer cylinder, and a .... A driving motor 8 is provided, and the rear end of the rotor main shaft is drivingly connected to the driving motor; an annular feeding port is arranged at the front end of the filter screen cylinder, and a discharge port is arranged at the rear end of the filter screen cylinder; a feed pipe 9 is connected to the upper side of the front end of the outer cylinder, and the discharge end of the feed pipe extends into the feeding port; a discharge port is arranged at the lower side of the rear end of the outer cylinder, a liquid outlet 11 is arranged at the lower side of the front end of the outer cylinder, and an air outlet 12 is arranged at the upper side of the rear end of the outer cylinder; a heating interlayer 13 is sleeved on the outer side of the rear part of the outer cylinder, a heat medium inlet 14 is arranged at the front end of the heating interlayer, and a heat medium outlet 15 is arranged at the rear end of the heating interlayer.

[0028] An observation hole is arranged above the front end of the outer cylinder, and a sealing plate 16 is arranged on the observation hole. The sealing plate is connected by a flange, and a tetrafluoroethylene sealing gasket is arranged in the middle of the flange. A plurality of spare interfaces 23 are also arranged on the sealing plate and the side wall of the outer cylinder, which can be used to introduce protective gas (such as nitrogen) and the like.

[0029] A funnel-shaped receiving hopper 10 is connected below the discharge port, and a discharge port is provided at the bottom of the receiving hopper. The lithium hexafluorophosphate crystal material falls from the discharge port of the filter screen cylinder and is collected and discharged through the receiving hopper.

[0030] The front end cover and the rear end cover are respectively connected to the outer cylinder flange through end cover sealing gaskets. The end cover sealing gaskets are made of polytetrafluoroethylene material and have good sealing performance and strong corrosion resistance.

[0031] The front end of the rotor main shaft is rotatably connected to the front end cover of the outer cylinder through a sealed bearing 17; the rear end of the rotor main shaft is rotatably connected to the rear end cover of the outer cylinder through a mechanical seal 18.

[0032] The sealed bearing is a bearing assembly, including a bearing itself 17-1, which is a tapered roller bearing, sleeved on the front end of the rotor main shaft, and also includes a bearing shell 17-2, a bearing end cover 17-3, a sealing shell 17-4 and a labyrinth ring 17-5, etc. The bearing shell is sleeved on the outside of the tapered roller bearing, a bearing end cover is fixedly provided on the front end of the bearing shell, the bearing shell is fixedly connected to the outer cylinder, the sealing shell is arranged on the rear side of the bearing shell, and an O-ring 17-6 is arranged between the bearing shell, the sealing shell and the outer cylinder, a Y-ring 17-7 is arranged between the rotor main shaft and the sealing shell, and the labyrinth ring is sleeved on the outside of the rotor main shaft behind the sealing shell.

[0033] The driving motor is connected to the rotor main shaft through a reducer 19, a driving gear 20 is arranged on the output shaft of the reducer, and a driven gear 21 meshing with the driving gear is arranged at the rear end of the rotor main shaft. A motor support 22 is arranged below the driving motor, and the top of the motor support is a 5° elevation support surface with a lower front and a higher rear.

[0034] The outer cylinder is a horizontal cylinder with a low front end and a high rear end and an elevation angle of 5°. During the process of upward spiral transportation of lithium hexafluorophosphate crystals in the filter rotor assembly, the liquid components contained therein are filtered out by the filter screen cylinder and flow downward to the liquid outlet, which is convenient for the separated hydrofluoric acid liquid to flow out quickly downward and can ensure the reliable transportation of the separated solids.

[0035] The filter screen cylinder is a porous screen cylinder, and the spiral blade group includes a spiral blade 7-1 arranged on the outside of the rotor main shaft, and a spiral ribbon blade 7-2 arranged on the periphery of the spiral blade. On the one hand, it ensures the transportation of lithium hexafluorophosphate crystals, and on the other hand, it also has the function of stirring the lithium hexafluorophosphate crystals. The crystals themselves rub against each other and collide with each other, which also has the function of breaking up and crushing.

[0036] The outer cylinder, the rotor main shaft, the filter screen cylinder and the spiral blade group are all made of 316L stainless steel, and all parts that may come into contact with lithium hexafluorophosphate crystals are made of 316L stainless steel with strong corrosion resistance.

[0037] The heat medium introduced into the heating interlayer is heat transfer oil. The heat transfer oil is circulated in the production line to recycle the heat energy of the heat transfer oil, which has good heat transfer effect and energy saving effect. The interior of the heating interlayer is a coil-type heat exchange structure, which indirectly heats and heats the separated solids at the rear end of the outer cylinder, which is beneficial to improving the thermal energy utilization rate and drying efficiency of the equipment.

[0038] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. Without departing from the scope and spirit of the described embodiments, many modifications and changes are obvious to ordinary technicians in this technical field. Any technical deformation made within the spirit and principles of the present invention falls within the protection scope of the present invention.

Claims

1. A solid-liquid separation and drying device for lithium hexafluorophosphate crystals, comprising a frame and an outer cylinder fixed on the frame, wherein the two ends of the outer cylinder are respectively sealed with a front cover and a rear cover, and the device is characterized in that: The outer cylinder is a horizontal cylinder with a low front end and a high rear end, and the elevation angle is 4 to 8 degrees; the front cover and the rear cover are respectively connected to the outer cylinder flange through the end cover sealing gasket; a rotatable filter rotor assembly is coaxially sleeved inside the outer cylinder; The filter rotor assembly includes a rotor main shaft, a filter screen cylinder and a spiral blade group, the spiral blade group is fixedly connected to the outside of the rotor main shaft, the filter screen cylinder is fixedly sleeved on the periphery of the spiral blade group, the two ends of the rotor main shaft are rotatably connected to the front and rear end covers of the outer cylinder, the front end of the rotor main shaft is rotatably connected to the front end cover of the outer cylinder through a sealing bearing; the rear end of the rotor main shaft is rotatably connected to the rear end cover of the outer cylinder through a mechanical seal; a driving motor is arranged at the rear of the outer cylinder, and the rear end of the rotor main shaft is transmission-connected to the driving motor; the driving motor and the rotor main shaft are transmission-connected through a reducer, a driving gear is arranged on the output shaft of the reducer, and a driven gear meshing with the driving gear is arranged at the rear end of the rotor main shaft; The filter screen is a porous screen, the spiral blade group includes spiral blades arranged outside the rotor main shaft, and spiral blades arranged outside the spiral blades, the front end of the filter screen is provided with an annular feeding port, and the rear end of the filter screen is provided with a discharge port; A feed pipe is connected to the upper side of the front end of the outer cylinder, and the discharge end of the feed pipe extends into the feeding port. A discharge port is arranged at the lower side of the rear end of the outer cylinder, a liquid outlet is arranged at the lower side of the front end of the outer cylinder, and an air outlet is arranged at the upper side of the rear end of the outer cylinder. The outer cylinder, the rotor main shaft, the filter screen cylinder and the spiral blade group are all made of 316L stainless steel; a funnel-shaped receiving hopper is connected below the discharge port, and a drop port is arranged at the bottom of the receiving hopper; A heating interlayer is sleeved on the outer side of the rear part of the outer cylinder, a heat medium inlet is arranged at the front end of the heating interlayer, and a heat medium outlet is arranged at the rear end of the heating interlayer. The heat medium introduced into the heating interlayer is heat transfer oil.

2. A lithium hexafluorophosphate crystal solid-liquid separation and drying device according to claim 1, characterized in that: An observation hole is arranged above the front end of the outer cylinder, and a sealing plate is arranged on the observation hole.

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