Flash evaporation treatment equipment and ternary positive electrode powder selective lithium extraction and recovery method

Abstract

The invention discloses flash evaporation treatment equipment and a ternary positive electrode powder selective lithium extraction recovery method.The flash evaporation treatment equipment comprises a tank body, a liquid inlet unit and a pressure control unit, a steam pipe is arranged at the top end of the tank body, a liquid outlet is formed in the bottom end of the tank body, one end of the liquid inlet unit extends into the tank body and is provided with a limiting plate, and the other end of the liquid inlet unit extends into the tank body; an air inlet is formed in the side face of the liquid inlet unit, and the pressure control unit is installed outside the end, located in the tank body, of the liquid inlet unit. The pressure control unit comprises a plugging piece arranged outside the liquid inlet unit in a sleeving mode, a first elastic piece arranged below the plugging piece and a second elastic piece arranged above the plugging piece, the bottom end of the plugging piece abuts against the first elastic piece, and the top end of the plugging piece is rotationally connected with the second elastic piece. The flash evaporation treatment equipment and the ternary positive electrode powder selective lithium extraction and recovery method are high in flash evaporation efficiency, and the concentration of lithium in the leachate can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and in particular to a flash evaporation treatment device and a method for selectively extracting and recovering lithium from ternary positive electrode powder. Background Art

[0002] Lithium-ion batteries have excellent properties such as high voltage, high cycle, high capacity and good thermal stability, and have been widely used. However, after multiple charge and discharge cycles, the active materials in lithium-ion batteries become inactivated and scrapped due to structural changes, so the number of retired and scrapped lithium-ion batteries is huge.

[0003] At present, the recycling methods of waste lithium-ion batteries are mainly divided into two types: wet process and pyroprocess, and the main method is to recover valuable metal elements. Among them, pyroprocess recovery has high energy consumption, serious pollution, and poor separation effect; wet process has the advantages of mild conditions and low energy consumption. Wet process for recycling lithium metal in lithium-ion batteries has been industrialized. At present, the main technical problems encountered in preparing lithium sulfate solution by wet process for recycling ternary positive electrode waste are: during the flash evaporation process, the flash evaporation efficiency is poor, it is impossible to prepare high-concentration lithium sulfate solution, and the stability is poor. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, one of the purposes of the present invention is to invent a flash evaporation treatment device with high flash evaporation efficiency.

[0005] The second object of the present invention is to invent a method for selectively extracting and recovering lithium from ternary positive electrode powder using the above-mentioned flash evaporation treatment equipment.

[0006] One of the purposes of the present invention adopts the following technical solution: A flash evaporation treatment equipment comprises a tank body, a liquid inlet unit and a pressure control unit, the top of the tank body is provided with a steam pipe, the bottom of the tank body is provided with a liquid discharge port, one end of the liquid inlet unit extends into the tank body and is installed with a limit plate, an air inlet is opened on the side of the liquid inlet unit, and the pressure control unit is installed on the outside of the liquid inlet unit at one end of the tank body, the pressure control unit comprises a sealing member sleeved on the outside of the liquid inlet unit, a first elastic member arranged below the sealing member and a second elastic member arranged above the sealing member, the bottom end of the sealing member abuts against the first elastic member, the top end of the sealing member is rotatably connected with the second elastic member, the end of the first elastic member away from the sealing member is fixedly connected to the limit plate, and the second elastic member is suitable for expanding and contracting under the action of air pressure in the tank body to drive the sealing member to slide along the length of the liquid inlet unit to block or open the air inlet.

[0007] Furthermore, the second elastic member includes a cylinder with a lower opening and a sealing plate. The sealing plate is slidably and sealingly arranged in the cylinder, and the top end of the blocking member is rotatably connected to the sealing plate.

[0008] Furthermore, the second elastic member further comprises a spring, the spring is arranged in the cylinder and two ends of the spring are respectively in contact with the sealing plate and the inner wall of the cylinder.

[0009] Furthermore, the second elastic member is composed of at least two air springs distributed in a circular array with the liquid inlet unit as the center.

[0010] Furthermore, a first mounting groove is provided at the top of the blocking member, a second mounting groove is opened at a position of the sealing plate corresponding to the first mounting groove, the first mounting groove cooperates with the second mounting groove to form a receiving space, and a plurality of balls are evenly arranged in the receiving space.

[0011] Furthermore, it also includes a cleaning unit, which includes a connecting rod and a cleaning rod arranged in the tank body, and a driving assembly arranged outside the tank body and transmission connected to the liquid inlet unit, the liquid inlet unit is suitable for rotating relative to the tank body under the drive of the driving assembly, the side wall of the liquid inlet unit is provided with a slide groove, the slide groove extends along the length direction of the liquid inlet unit, a slider slidably matched with the slide groove is provided on the inner side of the blocking member, one end of the connecting rod is connected to the blocking member, and the other end is connected to the cleaning rod.

[0012] Furthermore, the liquid inlet unit includes a liquid inlet pipe and a rotating sleeve mounted on the outside of the liquid inlet pipe, the air inlet is opened on the side wall of the rotating sleeve and is connected to the liquid inlet pipe, the top end of the rotating sleeve passes through the tank body and is transmission-connected to the driving assembly, the limit plate is installed at the bottom end of the rotating sleeve, the slide groove is opened on the side of the rotating sleeve, and a slider adapted to the slide groove is arranged on the inner side of the sealing member.

[0013] Furthermore, it also includes a reactor, wherein the end of the liquid inlet unit away from the tank body is connected to the reactor, a stirring blade is rotatably installed in the reactor, a stirring motor transmission-connected to the stirring blade is installed at the top of the reactor, and a heating resistance wire is arranged outside the reactor.

[0014] Furthermore, it also includes a steam condensation tower, which is connected to the tank body through a steam pipe.

[0015] The second object of the present invention adopts the following technical solution: A method for selectively extracting and recovering lithium from ternary positive electrode powder comprises the above-mentioned flash evaporation treatment equipment, and further comprises the following steps: Blending step: Mix the ternary cathode powder with water at a solid-liquid ratio of 1: (2.0-5.5) to obtain a ternary cathode solution; Pretreatment step: putting the ternary cathode solution, additives and dilute sulfuric acid into a pretreatment container for mixed reaction to obtain a pretreatment slurry, the reaction time is 3-5 hours; Lithium extraction step: adding the pretreated slurry after the reaction into a reactor to carry out a selective lithium extraction reaction to obtain a lithium-rich leaching slurry; Flash discharging step: transferring the leached slurry from the reactor into the flash treatment equipment, and completing the discharging by positive pressure; Filter pressing and oil removal step: filtering the leached slurry in the flash treatment equipment through a filter press to obtain a leachate, and then the leachate enters the filter press oil removal device for filter pressing and oil removal and impurity removal to obtain a high-concentration and high-purity lithium sulfate solution after impurity removal; Preparation steps of sodium carbonate solution: add pure water into the preparation tank and heat it to 60°C~70°C, then add sodium carbonate solid and stir, and filter after stirring evenly to obtain sodium carbonate solution; Lithium carbonate preparation step: adding sodium carbonate solution into a reaction vessel, and slowly spraying the lithium sulfate solution obtained in the pressure deoiling step into the reaction vessel in the form of a spray to prepare lithium carbonate, the reaction temperature is 85°C-95°C, the stirring rate is 80rpm-120rpm, and the reaction time is 60min-80min; Filtration and drying step: the lithium carbonate reaction slurry is passed through a centrifuge to obtain wet lithium carbonate, which is washed 2-3 times at a temperature of 90°C and transferred to a drying device for drying. The washing water is returned for use. The dried lithium carbonate is subjected to air flow milling, demagnetization, screening and packaging to obtain lithium carbonate that meets battery grade standards.

[0016] Beneficial effects: By extending the liquid inlet unit into the tank body, opening the air inlet on the side wall of the liquid inlet unit, and sleeved a plugging member on the outside of the liquid inlet unit, and arranging the first elastic member and the second elastic member at both ends of the plugging member, the plugging member can dynamically adjust the fluid flow entering the flash evaporation treatment equipment according to the air pressure in the tank body, so that the air pressure in the tank body is maintained at a certain level and a certain pressure difference is maintained with the input fluid, thereby ensuring the flash evaporation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a flash evaporation treatment equipment of the present invention; Figure 2 A cross-sectional view of a flash evaporation treatment device according to the present invention; Figure 3 A cross-sectional view of a flash tank of a flash treatment equipment according to the present invention; Figure 4 for Figure 3 Magnified view at A in the middle; Figure 5It is a structural schematic diagram of a cleaning unit of a flash treatment equipment of the present invention; Figure 6 The present invention is a flow chart of a method for selectively extracting and recovering lithium from a ternary positive electrode powder.

[0018] Reference numerals 10. Tank body; 101. Steam pipe; 102. Liquid discharge port; 20. Liquid inlet unit; 201. Liquid inlet pipe; 202. Rotating sleeve; 2021. Air inlet; 2022. Slide; 2023. Limiting plate; 30. Pressure control unit; 301. Blocking member; 3011. Sliding block; 302. First elastic member; 303. Second elastic member; 3031. Cylinder body; 3032. Sealing plate; 3033. Spring; 40. Cleaning unit; 401. Connecting rod; 402. Cleaning rod; 403. Reinforcement frame; 404. Driving assembly; 50. Steam condensation tower; 60. Reactor. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0020] In the description of the present invention, it should be understood that the terms "center", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] like Figure 1-5 As shown, a flash treatment device includes a tank body 10, a liquid inlet unit 20 and a pressure control unit 30. The top of the tank body 10 is provided with a steam pipe 101, the bottom of the tank body 10 is provided with a liquid discharge port 102, one end of the liquid inlet unit 20 extends into the tank body 10 and is installed with a limit plate 2023, the side of the liquid inlet unit 20 is provided with an air inlet 2021, the pressure control unit 30 is installed on the outside of the liquid inlet unit 20 located at one end of the tank body 10, and the pressure control unit 30 includes a plugging member 301 sleeved on the outside of the liquid inlet unit 20, and a pressure control unit 302 is provided. The first elastic member 302 is provided below the blocking member 301, and the second elastic member 303 is provided above the blocking member 301. The bottom end of the blocking member 301 abuts against the first elastic member 302, and the top end of the blocking member 301 is rotatably connected to the second elastic member 303. The end of the first elastic member 302 away from the blocking member 301 is fixedly connected to the limiting plate 2023, and the second elastic member 303 is suitable for expanding and contracting under the action of the air pressure in the tank body 10 to drive the blocking member 301 to slide along the length of the liquid inlet unit 20 to block or open the air inlet 2021.

[0024] In the present invention, the blocking member 301 may be composed of two upper and lower blocking units spaced apart from each other. When performing the blocking work, the blocking unit located at the lower part will move upward driven by the elastic force of the first elastic member 302 and the second elastic member 303, thereby blocking the air inlet 2021; of course, the blocking member 301 in the present invention may also be a long tube body, with an opening portion connected to the air inlet 2021 provided on the side of the tube body. When performing the blocking work, the blocking member 301 moves upward to stagger the opening portion and the air inlet 2021 to block the air inlet 2021, and when working normally, the blocking member 301 moves downward to align and connect the opening portion and the air inlet 2021.

[0025] In the present embodiment, a reactor 60 and a steam condensation tower 50 are also included. The end of the liquid inlet unit 20 away from the tank body 10 is connected to the reactor 60. A stirring blade is rotatably installed in the reactor 60. A stirring motor connected to the stirring blade is installed at the top of the reactor 60. A heating resistance wire is arranged outside the reactor 60. The steam condensation tower 50 is connected to the tank body through a steam pipe.

[0026] During operation, the prefabricated slurry enters the reactor, and the stirring motor drives the stirring blades to stir the prefabricated slurry. At the same time, the heating resistance wire heats the reactor. The prefabricated slurry in the reactor reacts under the heat to increase the lithium content in the prefabricated slurry. At the same time, the pressure in the reactor increases after heating. The prefabricated slurry in the reactor will be squeezed into the flash evaporation treatment equipment through the liquid inlet unit 20 under the action of the pressure in the reactor. At this time, the tank body 10 is in a non-working state, and the first elastic member 302 and the second elastic member 303 are both in a compressed state. The lithium sulfate fluid to be flash evaporated enters the tank body 10 through the air inlet 2021. Since the pressure in the tank body 10 is lower than the pressure in the reactor, after the prefabricated slurry enters the tank body 10, its pressure is reduced, so that the boiling point of the high-pressure and high-temperature fluid flowing out of the air inlet 2021 is reduced. After entering the tank body, the moisture in the fluid will be quickly vaporized, thereby increasing the sulfuric acid in the fluid. lithium concentration; during the water vaporization process, the pressure in the tank body 10 continues to increase, thereby squeezing the second elastic member 303 to compress the second elastic member 303, and at the same time the first elastic member 302 stretches to drive the blocking member 301 to slide upward along the length direction of the liquid inlet unit 20 to block the air inlet 2021. In the process of the blocking member 301 blocking the air inlet 2021, the fluid flow rate entering the tank body 10 continues to decrease, thereby reducing the pressure rising speed in the tank body 10, until the blocking member 301 completely blocks the air inlet 2021, and the air pressure in the tank body 10 reaches a maximum value; then, the air pressure in the tank body 10 decreases as the steam and the high-concentration lithium sulfate fluid obtained after flash evaporation are discharged, the second elastic member 303 stretches, the first elastic member 302 is compressed, the blocking member 301 opens the air inlet 2021, and the fluid re-enters the tank body 10 for flash evaporation.

[0027] In addition, since a small amount of lithium is also evaporated during the evaporation of the slurry, the steam needs to enter the steam condensation tower 50 after being discharged from the tank body 10, and will be injected into the pre-reaction container again after condensation treatment, that is, in the pretreatment step for full utilization.

[0028] Since the evaporation effect of flash evaporation is related to the pressure and temperature in the flash evaporation treatment equipment, in the present invention, the liquid inlet unit 20 is extended into the tank body 10, and the air inlet 2021 is opened on the side wall of the liquid inlet unit 20, and a sealing member 301 is sleeved on the outside of the liquid inlet unit 20, and the first elastic member 302 and the second elastic member 303 are used to enable the sealing member 301 to dynamically adjust the fluid flow entering the flash evaporation treatment equipment according to the air pressure in the tank body 10, so that the air pressure in the tank body 10 is maintained at a certain level and a certain pressure difference is maintained with the input fluid, thereby ensuring the flash evaporation effect.

[0029] Specifically, in this embodiment, the second elastic member 303 includes a cylinder 3031 with a lower opening and a sealing plate 3032 . The sealing plate 3032 is slidingly sealed and disposed in the cylinder 3031 . The top end of the blocking member 301 is rotatably connected to the sealing plate 3032 .

[0030] Since the sealing plate 3032 is slidably sealed and arranged in the cylinder 3031, a closed space isolated from the outside is formed in the cylinder 3031, and the closed space is filled with gas, so that when the air pressure in the tank 10 rises, there is a pressure difference between the air pressure in the tank 10 and the air pressure in the closed space, and the gas in the tank 10 can press the sealing plate 3032, so that the sealing plate slides axially along the cylinder 3031 to shrink, so that the blocking member 301 can move upward to block the air inlet 2021; When the air pressure in the tank body 10 drops, the compressed gas in the enclosed space can expand to push the sealing plate to slide axially along the cylinder body 3031 to stretch, so that the blocking member 301 can move downward to open the air inlet 2021.

[0031] In addition, by adopting this arrangement, the blocking member 301 can be automatically controlled to block the air inlet 2021 after a problem occurs with the second elastic member 303. Specifically, when a problem occurs with the second elastic member 303, such as air leakage, the space inside the second elastic member 303 is directly connected to the tank body 10. At this time, only the spring 3033 of the second elastic member 303 is working. When the second elastic member 303 is in a normal state, the elastic force generated by the spring 3033 and the deformation of the second elastic member 303 body are generated. The elastic force of the first elastic member 302 is equal to the elastic force of the second elastic member 303. Therefore, due to the lack of the elastic force generated by the deformation of the second elastic member 303, the elastic force of the first elastic member 302 is greater than the elastic force of the second elastic member 303, so that the first elastic member 302 is stretched and the second elastic member 303 is contracted, so that the blocking member 301 moves upward, thereby blocking the air inlet 2021, so as to prevent the air inlet 2021 from continuously entering the liquid, causing the pressure in the tank body 10 to be too high and burst; In addition, since the top of the sealing member 301 is rotatably connected to the top of the second elastic member 303, after the first elastic member 302 fails, the second elastic member 303 is deformed under the action of the air pressure in the tank body 10 and can drive the sealing member 301 to move upward to block the air inlet 2021, so as to prevent the air inlet 2021 from continuously entering the liquid, causing the pressure in the tank body 10 to be too high and burst.

[0032] In addition, to ensure the telescopic effect of the second elastic member 303, in this embodiment, the second elastic member 303 also includes a spring 3033, which is arranged in the cylinder 3031 and the two ends of the spring 3033 are respectively in contact with the sealing plate 3032 and the inner wall of the cylinder 3031.

[0033] In order to reduce the friction of the sealing member 301 on the second elastic member 303, in the present embodiment, a first mounting groove is provided at the top of the sealing member 301, and a second mounting groove is provided at a position corresponding to the first mounting groove of the sealing plate 3032. The first mounting groove cooperates with the second mounting groove to form a accommodating space, and a plurality of balls are evenly arranged in the accommodating space.

[0034] Of course, in the present invention, in order to avoid insufficient sealing between the sealing plate 3032 and the cylinder 3031, the gas in the tank body 10 directly enters the cylinder 3031 and the second elastic member 303 fails. Therefore, in this embodiment, the second elastic member 303 can be replaced by an air spring group with better air tightness from the combination of the cylinder 3031 and the sealing plate 3032. The air spring group is composed of at least two air springs distributed in a circular array with the liquid inlet unit 20 as the center.

[0035] In addition, a detection pipe can also be added to the tank body 10, the end of the detection pipe is connected to an external recovery device, and a bursting piece is arranged on the detection pipe. When the air pressure in the tank body 10 exceeds the specified upper limit, the bursting piece will rupture under the air pressure in the tank body 10 to release the pressure, thereby avoiding the explosion caused by excessive pressure in the tank body 10.

[0036] In addition, in order to prevent the crystals formed after flash evaporation from adhering to the inner wall of the tank body 10, in the present embodiment, a cleaning unit 40 is further provided in the tank body 10, and the cleaning unit 40 includes a connecting rod 401 and a cleaning rod 402 arranged in the tank body 10, and a driving assembly 404 arranged outside the tank body 10 and transmission connected to the liquid inlet unit 20, and the liquid inlet unit 20 is suitable for rotating relative to the tank body 10 under the drive of the driving assembly 404, and the side wall of the liquid inlet unit 20 is provided with a slide groove 2022, and the slide groove 2022 extends along the length direction of the liquid inlet unit 20, and the inner side of the blocking member 301 is provided with a slider 3011 that slidably cooperates with the slide groove 2022, and one end of the connecting rod 401 is connected to the blocking member 301, and the other end is connected to the cleaning rod 402.

[0037] During operation, the driving component 404 drives the liquid inlet unit 20 to rotate, so as to drive the sealing member 301 slidably set on the liquid inlet unit 20 to rotate, thereby linking the cleaning rod 402 to rotate through the connecting rod 401, and cleaning the inner wall of the tank body 10 to scrape off the crystals on the inner wall of the tank body 10, and because the connecting rod 401 is connected to the sealing member 301, when the sealing member 301 drives the connecting rod 401 to rotate, the sealing member 301 will also drive the connecting rod 401 to move up and down, so that the cleaning rod 402 can move up and down during the rotation process to stir the incoming fluid to improve the flash evaporation effect.

[0038] Specifically, in this embodiment, the liquid inlet unit 20 includes a liquid inlet pipe 201 and a rotating sleeve 202 mounted on the outside of the liquid inlet pipe 201. The air inlet 2021 is provided on the side wall of the rotating sleeve 202 and is connected to the liquid inlet pipe 201. The top end of the rotating sleeve 202 passes through the tank body 10 and is transmission-connected to the driving assembly 404. The limiting plate 2023 is installed at the bottom end of the rotating sleeve 202. The slide groove 2022 is provided on the side of the rotating sleeve 202. The inner side of the blocking member 301 is provided with a slider 3011 adapted to the slide groove 2022.

[0039] In this embodiment, the driving assembly 404 is composed of a driving motor and a transmission gear group installed on the top of the tank body 10, a driving gear installed on the motor shaft of the driving motor, and a driven gear installed on the top of the rotating sleeve 202. The driving gear is connected to the driven gear through the transmission gear group, so that when the driving motor is working, it can drive the driven gear to rotate through the transmission gear group to drive the rotating sleeve 202 to rotate, and then the cleaning rod 402 is rotated through the sealing member 301 to clean the inner wall of the tank body 10.

[0040] In order to facilitate the movement of the blocking member 301 along the length direction of the rotating sleeve 202, in this embodiment, a bearing can be arranged on the inner side of the blocking member 301, and the rotating sleeve 202 is sleeved in the bearing to convert the friction between the blocking member 301 and the rotating sleeve 202 from sliding friction to rolling friction, thereby reducing the wear of the rotating sleeve 202 during the movement of the blocking member 301.

[0041] In addition, in order to extend the service life of the first elastic member 302 and the sealing member 301, in this embodiment, the connecting rod 401 and the cleaning rod 402 are made of titanium alloy material, thereby reducing the overall weight of the cleaning unit 40, thereby reducing the impact of the cleaning unit 40 on the first elastic member 302 and the sealing member 301.

[0042] In order to improve the cleaning effect, in the present embodiment, a plurality of cleaning rods 402 and connecting rods 401 are provided, and the connecting rods 401 are provided one-to-one with the cleaning rods 402. The cleaning unit 40 includes a reinforcing frame 403, and the reinforcing frame 403 is suitable for connecting the plurality of cleaning rods 402 into one.

[0043] like Figure 6 As shown, a method for selectively extracting lithium from ternary positive electrode powder includes the above-mentioned flash evaporation treatment equipment and further includes the following steps: Blending step: Mix the ternary cathode powder with water at a solid-liquid ratio of 1: (2.0-5.5) to obtain a ternary cathode solution; Pretreatment step: putting the ternary cathode solution, additives and dilute sulfuric acid into a pretreatment container for mixed reaction to obtain a pretreatment slurry, the reaction time is 3-5 hours; Lithium extraction step: adding the pretreated slurry after the reaction into a reactor to carry out a selective lithium extraction reaction to obtain a lithium-rich leaching slurry; Flash discharging step: transferring the leached slurry from the reactor into the flash treatment equipment, and completing the discharging by positive pressure; Filter pressing and oil removal step: filtering the leached slurry in the flash treatment equipment through a filter press to obtain a leachate, and then the leachate enters the filter press oil removal device for filter pressing and oil removal and impurity removal to obtain a high-concentration and high-purity lithium sulfate solution after impurity removal; Preparation steps of sodium carbonate solution: add pure water into the preparation tank and heat it to 60°C~70°C, then add sodium carbonate solid and stir, and filter after stirring evenly to obtain sodium carbonate solution; Lithium carbonate preparation step: adding sodium carbonate solution into a reaction vessel, and slowly spraying the lithium sulfate solution obtained in the pressure deoiling step into the reaction vessel in the form of a spray to prepare lithium carbonate, the reaction temperature is 85°C-95°C, the stirring rate is 80rpm-120rpm, and the reaction time is 60min-80min; Filtration and drying step: The lithium carbonate reaction slurry is passed through a centrifuge to obtain wet lithium carbonate, which is then washed 2-3 times at 90°C and transferred to a drying device for drying, and the washing water is returned for use. The dried lithium carbonate is subjected to jet milling, demagnetization, screening, and packaging to obtain lithium carbonate that meets battery grade standards.

[0044] The above content is a further detailed description of the present invention in combination with specific implementation methods. It cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the scope of protection determined by the claims submitted for the present invention.

Claims

1. A flash evaporation treatment equipment, characterized in that: The jar is provided with a cap, a cap, and a closure. The jar has a bottom, and a bottom. The jar has a bottom, and a bottom. The jar has a bottom. The jar has a bottom. The jar has a bottom. The jar has a bottom. The jar has a bottom. The jar has a bottom. The jar has a bottom. The jar has a bottom. The jar has a bottom. The jar has a bottom.

2. The flash treatment equipment according to claim 1, characterized in that: The second elastic member comprises a cylinder with a lower opening and a sealing plate. The sealing plate is slidably and sealingly disposed in the cylinder. The top end of the blocking member is rotatably connected to the sealing plate.

3. The flash treatment equipment according to claim 2, characterized in that: The second elastic member further comprises a spring, which is disposed in the cylinder and has two ends which respectively abut against the sealing plate and the inner wall of the cylinder.

4. The flash evaporation treatment equipment according to claim 1, characterized in that: The second elastic member is composed of at least two air springs distributed in a circular array with the liquid inlet unit as the center.

5. The flash treatment equipment according to claim 2, characterized in that: A first mounting groove is arranged at the top of the blocking member, a second mounting groove is opened at a position of the sealing plate corresponding to the first mounting groove, the first mounting groove cooperates with the second mounting groove to form a receiving space, and a plurality of balls are evenly arranged in the receiving space.

6. The flash evaporation treatment equipment according to claim 1, characterized in that: It also includes a cleaning unit, which includes a connecting rod and a cleaning rod arranged in the tank body, and a driving assembly arranged outside the tank body and transmission-connected to the liquid inlet unit, the liquid inlet unit is suitable for rotating relative to the tank body under the drive of the driving assembly, the side wall of the liquid inlet unit is provided with a slide groove, the slide groove extends along the length direction of the liquid inlet unit, a slider slidably matched with the slide groove is provided on the inner side of the blocking member, one end of the connecting rod is connected to the blocking member, and the other end is connected to the cleaning rod.

7. The flash treatment equipment according to claim 6, characterized in that: The liquid inlet unit includes a liquid inlet pipe and a rotating sleeve sleeved on the outside of the liquid inlet pipe, the air inlet is opened on the side wall of the rotating sleeve and is connected to the liquid inlet pipe, the top end of the rotating sleeve passes through the tank body and is transmission-connected to the driving assembly, the bottom end of the rotating sleeve is installed with the limiting plate, the side of the rotating sleeve is opened with the sliding groove, and the inner side of the blocking member is provided with a sliding block adapted to the sliding groove.

8. The flash treatment equipment according to claim 1, characterized in that: It also includes a reactor, wherein one end of the liquid inlet unit away from the tank body is connected to the reactor, a stirring blade is rotatably installed in the reactor, a stirring motor drivingly connected to the stirring blade is installed at the top of the reactor, and a heating resistance wire is arranged outside the reactor.

9. The flash evaporation treatment equipment according to claim 1, characterized in that: It also includes a steam condensation tower, which is connected to the tank body through a steam pipe.

10. A method for selectively extracting lithium from ternary positive electrode powder, characterized in that The flash treatment equipment according to any one of claims 1 to 9 further comprises the following steps: Blending step: Mix the ternary cathode powder with water at a solid-liquid ratio of 1: (2.0-5.5) to obtain a ternary cathode solution; Pretreatment step: putting the ternary cathode solution, additives and dilute sulfuric acid into a pretreatment container for mixed reaction to obtain a pretreatment slurry, the reaction time is 3-5 hours; Lithium extraction step: adding the pretreated slurry after the reaction into a reactor to carry out a selective lithium extraction reaction to obtain a lithium-rich leaching slurry; Flash discharging step: transferring the leached slurry from the reactor into the flash treatment equipment, and completing the discharging by positive pressure; Filter pressing and oil removal step: filtering the leached slurry in the flash treatment equipment through a filter press to obtain a leachate, and then the leachate enters the filter press oil removal device for filter pressing and oil removal and impurity removal to obtain a high-concentration and high-purity lithium sulfate solution after impurity removal; Preparation steps of sodium carbonate solution: add pure water into the preparation tank and heat it to 60°C~70°C, then add sodium carbonate solid and stir, and filter after stirring evenly to obtain sodium carbonate solution; Lithium carbonate preparation step: adding sodium carbonate solution into a reaction vessel, and slowly spraying the lithium sulfate solution obtained in the pressure deoiling step into the reaction vessel in the form of a spray to prepare lithium carbonate, the reaction temperature is 85°C-95°C, the stirring rate is 80rpm-120rpm, and the reaction time is 60min-80min; Filtration and drying step: the lithium carbonate reaction slurry is passed through a centrifuge to obtain wet lithium carbonate, which is washed 2-3 times at a temperature of 90°C and transferred to a drying device for drying. The washing water is returned for use. The dried lithium carbonate is subjected to air flow milling, demagnetization, screening and packaging to obtain lithium carbonate that meets battery grade standards.

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