Reaction device for preparing lithium hexafluorophosphate by gas-solid method

Abstract

The invention relates to a reaction device for preparing lithium hexafluorophosphate by a gas-solid method. The reaction device for preparing the lithium hexafluorophosphate through the gas-solid method comprises a reaction cylinder, a center shaft is rotationally installed in the reaction cylinder, stirring blades are arranged on the center shaft, a plurality of spiral conveyors arranged around the center shaft are arranged in the reaction cylinder, and each spiral conveyor comprises a shell and an auger rotationally installed in the shell. The upper end and the lower end of the shell are provided with a discharging port and a feeding port respectively, the reaction cylinder is provided with a first driving mechanism for driving the center shaft and the auger to rotate, the reaction cylinder is provided with a phosphorus pentafluoride gas inlet pipe, the upper end of the reaction cylinder is provided with a plurality of sleeves in a guiding mode, and the sleeves are provided with lithium fluoride feeding pipes. And the plurality of sleeves are arranged right above the plurality of screw conveyors in a one-to-one correspondence manner. Lithium fluoride can be continuously fed into the reaction cylinder, leakage of phosphorus pentafluoride gas in the reaction cylinder is avoided, and the lithium fluoride continuously fed into the reaction cylinder can be in full contact with the phosphorus pentafluoride gas and react with the phosphorus pentafluoride gas.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium hexafluorophosphate production equipment, and in particular relates to a reaction device for preparing lithium hexafluorophosphate by a gas-solid method. Background Art

[0002] Lithium hexafluorophosphate is the most commonly used electrolyte in lithium batteries and is also the most expensive part of the battery. Since lithium hexafluorophosphate has a moderate ion migration number and dissociation constant in common organic solvents, it has good antioxidant properties and aluminum foil passivation ability, and can match various positive and negative electrode materials. Therefore, in the short and even medium term, lithium hexafluorophosphate is an irreplaceable raw material for lithium battery electrolytes.

[0003] There are generally four methods for preparing lithium hexafluorophosphate: gas-solid reaction method, hydrogen fluoride solvent method, organic solvent method and ion exchange method. The gas-solid reaction method is to prepare lithium hexafluorophosphate by direct gas-solid reaction of high-purity lithium fluoride and phosphorus pentafluoride, minus the use of hydrofluoric acid, and recycle the unreacted phosphorus pentafluoride gas in the process. When high-purity lithium fluoride reacts with phosphorus pentafluoride, the usual practice is to add high-purity lithium fluoride and phosphorus pentafluoride to a gas-solid reaction device in a set ratio for reaction. If a fixed amount of high-purity lithium fluoride is added to the reaction device all at once, it will accumulate at the bottom of the reaction device, and the high-purity lithium fluoride and phosphorus pentafluoride gas cannot fully contact, the reaction time is long, and the reaction effect is poor. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a reaction device for preparing lithium hexafluorophosphate by gas-solid method.

[0005] The technical solution of a reaction device for preparing lithium hexafluorophosphate by a gas-solid method of the present invention is:

[0006] A reaction device for preparing lithium hexafluorophosphate by gas-solid method, comprising a reaction cylinder, a central shaft is rotatably installed in the reaction cylinder, a stirring blade is arranged on the central shaft, a plurality of screw conveyors arranged around the central shaft are arranged in the reaction cylinder, the screw conveyor comprises a shell and an auger rotatably installed in the shell, a discharge port and a feed port are respectively arranged at the upper and lower ends of the shell, a first driving mechanism for driving the central shaft and the auger to rotate is arranged on the reaction cylinder, a phosphorus pentafluoride air inlet pipe is arranged on the reaction cylinder, a plurality of sleeves are installed on the upper end guide of the reaction cylinder, and a stirring blade is arranged on the sleeve There is a lithium fluoride feeding pipe, and several sleeves are arranged one by one directly above several screw conveyors. The rotating shaft of the auger extends out of the upper side of the shell and the upper end extends into the sleeve. The upper end of the rotating shaft of the auger is provided with a sealing plug matching the sleeve. The upper end of the reaction cylinder is fixedly connected with several inserts inserted into the sleeve one by one. The reaction cylinder is provided with a second driving mechanism for driving the sleeve to move upward so that the sealing plug unseals the sleeve and the insert seals the lithium fluoride inlet pipe. The insert is sleeved with a reset spring for pushing the sleeve to move downward so that the sealing plug seals the sleeve and the insert unseals the lithium fluoride inlet pipe.

[0007] Furthermore, the upper side of the central shaft is a hollow structure, and the outer wall of the central shaft is provided with a plurality of vertical grooves connected to the hollow structure. A screw is rotatably installed in the central shaft, and the upper end of the screw is transmission-connected to the second driving mechanism through a split electromagnetic coupling. A partition assembly is provided on the screw, and the outer wall of the partition assembly is slidingly sealed with the inner wall of the reaction cylinder.

[0008] Furthermore, the partition assembly includes an inner plate, a sealed bearing and an outer plate, the outer wall of the inner plate is fixedly connected to the inner ring of the sealed bearing, the inner wall of the outer plate is fixedly connected to the outer ring of the sealed bearing, the inner plate is provided with a threaded hole matching the screw rod, and the inner plate is provided with a through hole matching the outer wall of the sleeve.

[0009] Furthermore, the first driving mechanism includes a first driving motor, a driving pulley, a plurality of driven pulleys and a synchronous belt. The first driving motor is fixedly connected to the lower side of the reaction cylinder through a motor fixing seat. The rotating shaft of the auger extends downward from the lower side of the reaction cylinder. The plurality of driven pulleys are fixedly connected one by one to the lower end of the rotating shaft of the auger. The plurality of synchronous belts are wrapped around the plurality of driven pulleys and the driving pulleys.

[0010] Furthermore, the second driving mechanism includes a second driving motor, a gear steering gear, a plurality of transmission shafts and a cam, the output shaft of the second driving motor is fixedly connected to the input end of the gear steering gear, the gear steering gear is fixedly connected to the upper side of the reaction cylinder, the gear steering gear has an output shaft extending downward and a plurality of horizontally extending output shafts, the output shaft extending upward of the gear steering gear is fixedly connected to the input piece of the split electromagnetic coupling, the upper end of the screw rod is fixedly connected to the output piece of the split electromagnetic coupling, the number of horizontally extending output shafts of the gear steering gear is equal to the number of transmission shafts and sleeves, a plurality of transmission shafts are fixedly connected one by one to the horizontally extending output shafts of the gear steering gear, a plurality of the cams are fixedly connected one by one to the ends of a plurality of transmission shafts, and a plurality of the sleeves are provided with contact plates matching the cams on the outer walls.

[0011] Furthermore, a flange is provided at the upper end of the sleeve, the insert is fixedly connected to the reaction tube via a fixing plate, and both ends of the reset spring are fixedly connected to the flange and the fixing plate respectively.

[0012] Furthermore, the phosphorus pentafluoride inlet pipe is located at the lower side of the outer wall of the reaction cylinder, a discharge pipe is provided at the lower end of the reaction cylinder, a discharge valve is provided on the discharge pipe, and a plurality of support legs are provided at the lower end of the reaction cylinder.

[0013] The present invention provides a reaction device for preparing lithium hexafluorophosphate by gas-solid method, which has the following beneficial effects:

[0014] The reaction device for preparing lithium hexafluorophosphate by the gas-solid method of the present invention can realize the continuous introduction of lithium fluoride into the reaction tube, and avoids the leakage of phosphorus pentafluoride gas in the reaction tube. The lithium fluoride continuously entering the reaction tube can fully contact and react with the phosphorus pentafluoride gas. The stirring blade on the central axis stirs the material in the reaction tube, and the screw conveyor conveys the material at the bottom of the reaction tube upward, further allowing the reaction to proceed fully. After a period of reaction, the pressure in the reaction tube becomes lower because the phosphorus pentafluoride gas in the reaction tube is consumed, which will affect the reaction effect and reaction rate to a certain extent. By making the partition assembly go downward, the reaction tube space on the lower side of the partition assembly is reduced, and the pressure is increased, which helps to improve the reaction rate and reaction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The structure of the reaction device for preparing lithium hexafluorophosphate by gas-solid method of the present invention is shown in FIG. Figure 1 ;

[0016] Figure 2 The structure of the reaction device for preparing lithium hexafluorophosphate by gas-solid method of the present invention is shown in FIG. Figure 2 ;

[0017] Figure 3It is a cross-sectional view of a reaction device for preparing lithium hexafluorophosphate by a gas-solid method of the present invention;

[0018] Figure 4 yes Figure 3 The enlarged view of point A in the middle;

[0019] Figure 5 It is a partial structural schematic diagram of a reaction device for preparing lithium hexafluorophosphate by a gas-solid method of the present invention;

[0020] Figure 6 It is a schematic structural diagram of a separator assembly in a reaction device for preparing lithium hexafluorophosphate by a gas-solid method of the present invention;

[0021] In the figure: 1, reaction cylinder; 2, cylinder cover; 3, support leg; 4, phosphorus pentafluoride air inlet pipe; 5, stop valve; 6, discharge pipe; 7, discharge valve; 8, central axis; 9, stirring blade; 10, vertical groove; 11, screw rod; 12, outer plate; 13, sealed bearing; 14, inner plate; 15, shell; 16, feed port; 17, discharge port; 18, rotating shaft; 19, motor fixing seat; 20, first drive motor; 21, driving pulley; 22, driven pulley; 23, synchronous belt; 24, sealing plug; 25, guide sleeve; 26, lithium fluoride feed pipe; 27, fixing plate; 28, insert; 29, flange; 30, reset spring; 31, contact plate; 32, second drive motor; 33, gear steering gear; 34, transmission shaft; 35, cam. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0023] The specific embodiment of the reaction device for preparing lithium hexafluorophosphate by gas-solid method of the present invention is as follows: Figures 1 to 6 As shown, it includes a reaction cylinder 1, which is cylindrical, and the upper end of the reaction cylinder 1 is fixedly connected to a cylinder cover 2 by bolts. The lower end of the reaction cylinder 1 is fixedly connected to a plurality of support legs 3, and the plurality of support legs 3 are evenly spaced along the circumference of the reaction cylinder 1. The lower end of the reaction cylinder 1 is fixedly connected to a discharge pipe 6, and a discharge valve 7 is installed on the discharge pipe 6.

[0024] The reaction tube 1 has a central axis 8 inside, and the lower end of the central axis 8 has a small diameter section, which is rotatably mounted at the center of the bottom wall of the reaction tube 1 through a bearing, and the lower end of the small diameter section extends out from the lower side of the reaction tube 1. The upper end of the central axis 8 is a hollow structure, and the outer wall of the central axis 8 has a plurality of vertical grooves 10 extending vertically, and the plurality of vertical grooves 10 are evenly spaced along the circumference of the central axis 8. A screw rod 11 is rotatably mounted inside the central axis 8 through a bearing, and a partition assembly is provided on the screw rod 11. The partition assembly includes an inner plate 14, a sealed bearing 13, and an outer plate 12, the outer wall of the inner plate 14 is fixedly connected to the inner ring of the sealed bearing 13, the inner wall of the outer plate 12 is fixedly connected to the outer ring of the sealed bearing 13, a threaded hole matching the screw rod 11 is provided on the inner plate 14, and a through hole matching the central axis 8 between the two vertical grooves 10 is provided on the inner plate 14. A plurality of stirring blades 9 are fixedly connected to the central shaft 8 , and the uppermost stirring blade 9 is located on the central shaft 8 at the lower side of the vertical groove 10 .

[0025] Four screw conveyors are fixedly connected to the interior of the reaction barrel 1. The four screw conveyors are arranged vertically and evenly spaced along the circumference of the reaction barrel 1. The screw conveyor includes a shell 15 and an auger rotatably installed in the shell 15. The lower end of the shell 15 is open and the upper end is sealed. The lower end of the shell 15 is fixedly connected to the bottom wall of the reaction barrel 1. A feed port 16 is provided on the lower side of the outer wall of the shell 15, and the feed port 16 is arranged toward the central axis 8. A discharge port 17 is provided on the upper side of the outer wall of the shell 15, and the discharge port 17 is also arranged toward the central axis 8. The lower end of the auger extends out of the lower side of the reaction barrel 1, and the auger is rotatably connected to the bottom wall of the reaction barrel 1 through a sealed bearing 13.

[0026] The bottom wall of the reaction tube 1 is provided with a first driving mechanism for driving the central shaft 8 and the augers of the four screw conveyors to rotate. Preferably, the first driving mechanism includes a first driving motor 20, a driving pulley 21, four driven pulleys 22 and four synchronous belts 23. The first driving motor 20 is fixedly connected to the lower side of the reaction tube 1 through a motor fixing seat 19, and the output shaft of the first driving motor 20 extends into the motor fixing seat 19. The output shaft of the first driving motor 20 is fixedly connected to the small diameter section of the central shaft 8 through a coupling. The driving pulley 21 is coaxially fixedly connected to the small diameter section of the central shaft 8, and the driving pulley 21 has four belt grooves. The four driven pulleys 22 are fixedly connected to the lower ends of the rotating shafts 18 of the four augers one by one, and the four synchronous belts 23 are surrounded by the four driven pulleys 22 and the four belt grooves of the driving pulley 21. After the first driving motor 20 is started, it can drive the central shaft 8 and the augers of the four screw conveyors to rotate.

[0027] The guide assembly on the cylinder cover 2 is equipped with four sleeves. In order to make the sleeves move more smoothly in the up and down directions, four guide sleeves 25 that match the sleeves are fixedly connected to the cylinder cover 2. The outer plate 12 of the partition has four perforations that match the four sleeves respectively, and the lower end of the sleeve extends into the lower side of the outer plate 12. The sleeve located on the upper side of the cylinder cover 2 is fixedly connected with an inclined lithium fluoride feed pipe 26, and the lithium fluoride feed pipe 26 extends upwardly. The rotating shaft 18 of the screw conveyor extends upward from the upper side of the housing 15, and the upper end of the rotating shaft 18 of the screw conveyor enters the interior of the sleeve, and the end of the rotating shaft 18 is fixedly connected with a sealing plug 24 that seals with the sleeve. A flange 29 is fixedly connected to the outer wall of the upper end of the sleeve, and four plugs 28 are fixedly connected to the cylinder cover 2 through four fixed plates 27. The fixed plate 27 includes a horizontally arranged circular plate and a vertical plate extending vertically at the lower side of the circular plate, and the lower end of the vertical plate is fixedly connected to the cylinder cover 2 by bolts. Four inserting tubes 28 are inserted into the upper end of the sleeve in a one-to-one correspondence, and the inserting tubes 28 are coaxially arranged with the circular plate. A return spring 30 is sleeved on the inserting tube 28, and the two ends of the return spring 30 are fixedly connected to the circular plate and the flange 29 respectively.

[0028] The barrel cover 2 is provided with a second driving mechanism for driving the screw rod 11 to rotate and the sleeve to move upward. Preferably, the second driving mechanism includes a second driving motor 32, a gear steering gear 33, four transmission shafts 34 and four cams 35. The gear steering gear 33 is in a hexagonal shape. The upper side of the gear steering gear 33 has an input hole matching the output shaft of the second driving motor 32, and the other five sides have output shafts. The output shaft arranged in the direction of the gear steering gear 33 is connected to the screw rod 11 through a split electromagnetic coupling. The split electromagnetic coupling includes an output member and an input member. The input member is fixedly connected to the lower end of the output shaft arranged downward of the gear steering gear 33, and the output member is fixedly connected to the upper end of the screw rod 11. The four transmission shafts 34 are respectively fixedly connected to the ends of the four horizontally arranged output shafts of the gear steering gear 33 through couplings, and the four cams 35 are respectively fixedly connected to the ends of the transmission shaft 34. The outer wall of the sleeve is fixedly connected with a contact plate 31 matching the cam 35.

[0029] When the reaction device for preparing lithium hexafluorophosphate by gas-solid method of the present invention is used, the external lithium fluoride material pipe is connected to the four lithium fluoride feed pipes 26 on the reaction tube 1, and the external phosphorus pentafluoride feed pipe is connected to the phosphorus pentafluoride air inlet pipe 4 on the reaction tube 1. The phosphorus pentafluoride air inlet pipe 4 passes all the phosphorus pentafluoride required for the reaction into the reaction tube 1, and the stop valve 5 on the phosphorus pentafluoride air inlet pipe 4 is closed. The second drive motor 32 is started, at which time, the split electromagnetic coupling is in a power-off state, and the output and input parts of the split electromagnetic coupling are in a separated state. The second drive motor 32 drives the four transmission shafts 34 to rotate, and the four transmission shafts 34 drive the four cams 35 to rotate. When the cam 35 is in the push stroke, the cam 35 pushes the sleeve to move upward. When the sleeve is upward to release the seal with the sealing plug 24, the lithium fluoride feed pipe 26 on the sleeve is sealed with the insert 28, and the lithium fluoride in the sleeve enters the reaction tube 1 from the lower end of the sleeve. When the cam 35 is in the return stroke, the sleeve moves downward under the action of the reset spring 30, and when the sleeve moves to the sealing plug 24, the cannula 28 and the lithium fluoride feed pipe 26 are unsealed, and the lithium fluoride in the lithium fluoride feed pipe 26 enters the sleeve. In this way, the lithium fluoride is continuously introduced into the reaction tube 1, and the leakage of the phosphorus pentafluoride gas in the reaction tube 1 is avoided. The lithium fluoride continuously entering the reaction tube 1 can fully contact and react with the phosphorus pentafluoride gas. In this process, the first drive motor 20 keeps the starting state, and the first drive motor 20 drives the central shaft 8 and four screw conveyors to rotate. The stirring blade 9 on the central shaft 8 stirs the material in the reaction tube 1, and the screw conveyor transports the material at the bottom of the reaction tube 1 upward, further allowing the reaction to be fully carried out. After a period of reaction, because the phosphorus pentafluoride gas in the reaction tube 1 is consumed, the pressure in the reaction tube 1 becomes low, which will affect the reaction effect and reaction rate to a certain extent. In order to increase the pressure in the reaction tube 1, the first drive motor 20 is disconnected, the split electromagnetic coupling is energized, the second drive motor 32 drives the screw 11 to rotate, and the screw 11 drives the partition assembly downward. After the partition assembly descends to a certain height, the split electromagnetic coupling is disconnected and the first drive motor 20 is started. After the partition assembly descends, the space of the reaction tube 1 below the partition assembly is reduced, and the pressure is increased, which helps to improve the reaction rate and reaction effect.

[0030] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A reaction device for preparing lithium hexafluorophosphate by gas-solid method, characterized in that: The invention comprises a reaction cylinder, wherein a central axis is rotatably installed in the reaction cylinder, a stirring blade is arranged on the central axis, a plurality of screw conveyors arranged around the central axis are arranged in the reaction cylinder, the screw conveyor comprises a shell and an auger rotatably installed in the shell, a discharge port and a feed port are respectively arranged at the upper and lower ends of the shell, a first driving mechanism for driving the central axis and the auger to rotate is arranged on the reaction cylinder, a phosphorus pentafluoride air inlet pipe is arranged on the reaction cylinder, a plurality of sleeves are installed on the upper guide of the reaction cylinder, a lithium fluoride feed pipe is arranged on the sleeve, if The sleeves are arranged one by one directly above a number of screw conveyors, the rotating shaft of the auger extends out of the upper side of the shell and the upper end extends into the sleeve, the upper end of the rotating shaft of the auger is provided with a sealing plug matching the sleeve, the upper end of the reaction cylinder is fixedly connected with a number of insert tubes inserted into the sleeve one by one, the reaction cylinder is provided with a second driving mechanism for driving the sleeve to move upward so that the sealing plug unseals the sleeve and the insert tube seals the lithium fluoride inlet tube, and the insert tube is provided with a reset spring for pushing the sleeve to move downward so that the sealing plug seals the sleeve and the insert tube unseals the lithium fluoride inlet tube.

2. The reaction device for preparing lithium hexafluorophosphate by gas-solid method according to claim 1, characterized in that: The upper side of the central shaft is a hollow structure, and the outer wall of the central shaft is provided with a plurality of vertical grooves connected with the hollow structure. A screw is rotatably installed in the central shaft, and the upper end of the screw is transmission-connected to the second driving mechanism through a split electromagnetic coupling. A partition assembly is provided on the screw, and the outer wall of the partition assembly is slidingly sealed with the inner wall of the reaction cylinder.

3. The reaction device for preparing lithium hexafluorophosphate by gas-solid method according to claim 2, characterized in that: The partition assembly includes an inner plate, a sealed bearing and an outer plate. The outer wall of the inner plate is fixedly connected to the inner ring of the sealed bearing, the inner wall of the outer plate is fixedly connected to the outer ring of the sealed bearing, the inner plate is provided with a threaded hole matching the screw rod, and the inner plate is provided with a through hole matching the center axis.

4. The reaction device for preparing lithium hexafluorophosphate by gas-solid method according to claim 1, characterized in that: The first driving mechanism includes a first driving motor, a driving pulley, a plurality of driven pulleys and a synchronous belt. The first driving motor is fixedly connected to the lower side of the reaction cylinder through a motor fixing seat. The rotating shaft of the auger extends downward from the lower side of the reaction cylinder. The plurality of driven pulleys are fixedly connected to the lower end of the rotating shaft of the auger one by one. The plurality of synchronous belts are wrapped around the plurality of driven pulleys and the driving pulleys.

5. The reaction device for preparing lithium hexafluorophosphate by gas-solid method according to claim 2, characterized in that: The second driving mechanism includes a second driving motor, a gear steering gear, a plurality of transmission shafts and a cam. The output shaft of the second driving motor is fixedly connected to the input end of the gear steering gear. The gear steering gear is fixedly connected to the upper side of the reaction cylinder. The gear steering gear has an output shaft extending downward and a plurality of horizontally extending output shafts. The output shaft extending upward of the gear steering gear is fixedly connected to the input piece of the split electromagnetic coupling. The upper end of the screw rod is fixedly connected to the output piece of the split electromagnetic coupling. The number of horizontally extending output shafts of the gear steering gear is equal to the number of transmission shafts and sleeves. The plurality of transmission shafts are fixedly connected one by one to the horizontally extending output shafts of the gear steering gear. The plurality of cams are fixedly connected one by one to the ends of the plurality of transmission shafts. The outer walls of the plurality of sleeves are provided with contact plates matching the cams.

6. The reaction device for preparing lithium hexafluorophosphate by gas-solid method according to claim 5, characterized in that: The upper end of the sleeve is provided with a flange, the insert is fixedly connected to the reaction tube through a fixing plate, and the two ends of the reset spring are fixedly connected to the flange and the fixing plate respectively.

7. The reaction device for preparing lithium hexafluorophosphate by gas-solid method according to claim 1, characterized in that: The phosphorus pentafluoride air inlet pipe is located at the lower side of the outer wall of the reaction cylinder. A discharge pipe is provided at the lower end of the reaction cylinder. A discharge valve is provided on the discharge pipe. A plurality of supporting legs are provided at the lower end of the reaction cylinder.

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