Process for resource utilization of lithium iron phosphate production wastewater

Abstract

The application discloses a novel lithium iron phosphate production wastewater resource utilization process and relates to the technical field of lithium iron phosphate production.The process is characterized in that the wastewater is converted into clean steam by an evaporator, the steam is then transported into the interior of a double-screw compressor, the steam is made to be warmed by work of the double-screw compressor, the temperature of the steam reaches the temperature required in the lithium iron phosphate production process, the warmed steam is transported into a reaction kettle used for producing lithium iron phosphate, the steam serves as a heat source of the reaction kettle and provides heat for the reaction kettle, mother liquor concentrated in the evaporator due to evaporation of water is recovered into a crude product storage bin, lithium iron phosphate is produced after purification and cleaning, the lithium iron phosphate production wastewater is fully treated, the wastewater becomes steam used in the production process and product mother liquor, the use amount of the steam and pure water in the production process is reduced, the total loss of the product is reduced, the whole process is nearly zero emission, and the effect of energy saving, emission reduction, cost reduction and benefit increase is achieved.

Description

Technical Field

[0001] This invention relates to the field of lithium iron phosphate production technology, specifically a process for the resource utilization of wastewater from lithium iron phosphate production. Background Technology

[0002] Current lithium iron phosphate production generally employs the carbothermal reduction method, which mainly includes: drying and dehydrating lithium iron phosphate, grinding and mixing lithium carbonate and lithium iron phosphate, dispersing materials in a disperser, spray drying, briquetting and loading materials in a hydraulic press, sintering in a pusher furnace, ultrafine grinding by roller pressing, sieving, and packaging. In the three main processes of grinding and mixing lithium carbonate and lithium iron phosphate, dispersing materials in a disperser, and spray drying, a large amount of pure water is required as a medium. This results in the carbothermal reduction method using a significant amount of pure water during processing, which is ultimately produced as wastewater. The volume of wastewater is enormous, including drying condensate and flash condensate, requiring substantial investment in wastewater treatment and increasing production costs.

[0003] To address the aforementioned issues, an improved process for the resource utilization of wastewater from lithium iron phosphate production is now designed. Summary of the Invention

[0004] The purpose of this invention is to provide a process for the resource utilization of wastewater from lithium iron phosphate production, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A process for the resource utilization of wastewater from lithium iron phosphate production includes the following steps:

[0007] Step 1: Add the lithium iron phosphate production wastewater into the evaporator, and the evaporator will convert the wastewater into clean steam.

[0008] Step 2: The steam from Step 1 is transported to the interior of the twin-screw compressor through a gas pipeline. The twin-screw compressor performs work on the steam to raise its temperature, thereby reaching the temperature required in the lithium iron phosphate production process.

[0009] Step 3: The steam heated in Step 2 is transported through the steam outlet pipe to the reactor used for producing lithium iron phosphate, so that the high-temperature steam can serve as a heat source for the reactor.

[0010] Step 4: The mother liquor concentrated due to water evaporation inside the evaporator is recovered into the crude product storage tank, and after purification and cleaning, lithium iron phosphate is produced.

[0011] As a further aspect of the present invention: a feed pipe is installed at the upper end of the side wall of the evaporator, a discharge pipe is installed at the lower end of the side wall of the evaporator, a support frame is installed at the lower end of the evaporator, a heater for heating and evaporating lithium iron phosphate production wastewater is installed at the lower end of the inner wall of the evaporator, the input end of the gas supply pipe is installed at the upper end of the side wall of the evaporator, a stirring mechanism for stirring the lithium iron phosphate production wastewater is provided at the bottom of the evaporator, a lifting and spraying mechanism for accelerating the evaporation of lithium iron phosphate production wastewater is provided inside the evaporator, and a drive mechanism for simultaneously providing power to the stirring mechanism and the lifting and spraying mechanism is provided inside the support frame.

[0012] As a further embodiment of the present invention: the stirring mechanism includes a limiting cylinder, which is vertically installed at the center of the bottom of the evaporator. The upper end of the limiting cylinder is located inside the evaporator, and the lower end of the limiting cylinder passes through the evaporator and is located inside the support frame. A rotating cylinder is rotatably connected to the inner wall of the limiting cylinder. Several stirring blades for stirring the lithium iron phosphate production wastewater at the bottom of the evaporator are horizontally installed at the upper end of the side wall of the rotating cylinder, passing through the limiting cylinder. A toothed ring for driving the rotating cylinder to rotate is installed at the lower end of the side wall of the rotating cylinder, passing through the limiting cylinder.

[0013] As a further embodiment of the present invention: the lifting and spraying mechanism includes a movable rod, which is vertically slidably connected to the inner wall of the rotating cylinder. The lower end of the movable rod passes through the rotating cylinder and is fitted with a fixed plate. The side wall of the fixed plate is fitted with an installation frame for driving the fixed plate and the movable rod to move up and down. The upper end of the movable rod passes through the rotating cylinder and is fitted with an elastic telescopic rod. The spring inside the elastic telescopic rod is kept in a stretched state, causing the output end of the elastic telescopic rod to retract. The output end of the elastic telescopic rod is fitted with a bracket. An installation ring is fitted on the side of the bracket away from the elastic telescopic rod. Several fixed frames for filling wastewater are fitted on the upper end of the installation ring. Several drainage holes for spraying wastewater are opened on the side wall of the fixed frame near the elastic telescopic rod. The interior of the installation frame is provided with a detection component for detecting the evaporation of lithium iron phosphate production wastewater.

[0014] As a further embodiment of the present invention: the detection component includes a controller, the controller is installed at the bottom of the support frame, and a pressure sensor for measuring the resistance to downward movement of the bracket is installed at the bottom of the mounting frame, the detection end of the pressure sensor being in close contact with the upper end of the fixing plate.

[0015] As a further embodiment of the present invention: the driving mechanism includes a motor, which is installed at the lower end of the evaporator. A rotating rod is vertically installed at the output end of the motor. The lower end of the rotating rod is rotatably connected to the bottom of the support frame. A gear that meshes with a gear ring is installed on the upper side wall of the rotating rod. A reciprocating screw is installed on the side wall of the rotating rod below the gear. A moving block is rotatably connected to the side wall of the reciprocating screw by a thread. The end of the moving block near the mounting frame is installed on the side wall of the mounting frame.

[0016] As a further embodiment of the present invention: a rib for supporting the bracket is installed on the side of the lower end of the bracket away from the elastic telescopic rod, and the end of the rib near the elastic telescopic rod is installed at an angle downward at the output end of the elastic telescopic rod.

[0017] As a further aspect of the present invention, sealing rings for preventing wastewater leakage are installed on the inner walls of both the limiting cylinder and the rotating cylinder.

[0018] As a further aspect of the present invention, the side walls of the evaporator and the gas pipeline are provided with a heat insulation layer for heat preservation.

[0019] As a further embodiment of the present invention: a cleaning rod for cleaning the heater is vertically provided at the end of the stirring fan blade away from the rotating cylinder, and the side wall of the cleaning rod is in close contact with the side wall of the heater.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This invention effectively treats wastewater from lithium iron phosphate production, turning it into steam and mother liquor used in the production process. This reduces the amount of steam and pure water used in the production process, minimizes the loss of total product, and achieves near-zero emissions throughout the entire process, thus realizing energy conservation, emission reduction, cost reduction, and efficiency improvement.

[0022] This invention disperses and stirs lithium iron phosphate production wastewater using stirring fan blades, ensuring uniform heating and easy evaporation. Simultaneously, a moving fixed frame supports and lifts the wastewater, which is then sprayed out through a drain hole, increasing the evaporation area and improving the evaporation efficiency of the lithium iron phosphate production wastewater.

[0023] As the lithium iron phosphate production wastewater becomes thicker, the support frame no longer enters the wastewater. During movement, the elastic telescopic rod is stretched to prevent the fixed frame from bearing the thick lithium iron phosphate production wastewater.

[0024] As the wastewater from lithium iron phosphate production becomes thicker, the resistance on the support structure also increases. By using a pressure sensor to detect the resistance on the support structure in real time, it can be determined whether the wastewater from lithium iron phosphate production has reached the concentration standard, thereby controlling the evaporation of the wastewater. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the present invention.

[0026] Figure 2 This is a schematic diagram of the structure of the present invention.

[0027] Figure 3 This is a cross-sectional view of the present invention.

[0028] Figure 4 This is a schematic diagram of the drive mechanism in this invention.

[0029] Figure 5 This is a schematic diagram of the detection component in this invention.

[0030] Figure 6 This is a schematic diagram of the lifting and spraying mechanism in this invention.

[0031] The components are as follows: 1. Evaporator; 2. Feed pipe; 3. Elastic telescopic rod; 4. Heater; 5. Stirring blade; 6. Discharge pipe; 7. Limiting cylinder; 8. Gear ring; 9. Support frame; 10. Controller; 11. Rotating cylinder; 12. Mounting frame; 13. Rotating rod; 14. Reciprocating screw; 15. Moving block; 16. Twin-screw compressor; 17. Gas outlet pipe; 18. Gear; 19. Motor; 20. Moving rod; 21. Gas delivery pipe; 22. Fixing frame; 23. Drain hole; 24. Bracket; 25. Mounting ring; 26. Fixing plate; 27. Pressure sensor. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figures 1-6 In this embodiment of the invention, a process for the resource utilization of lithium iron phosphate production wastewater includes the following steps:

[0034] Step 1: Add the lithium iron phosphate production wastewater into the evaporator 1, and the evaporator 1 will convert the wastewater into clean steam.

[0035] Step 2: The steam from Step 1 is transported to the interior of the twin-screw compressor 16 through the gas delivery pipe 21. The twin-screw compressor 16 performs work on the steam to raise its temperature to the temperature required in the lithium iron phosphate production process.

[0036] Step 3: The steam heated in Step 2 is transported through the steam outlet pipe 17 to the reactor used for producing lithium iron phosphate, so that the high-temperature steam serves as the heat source for the reactor.

[0037] Step 4: The concentrated mother liquor inside evaporator 1 due to water evaporation is recovered into the crude product storage tank, and lithium iron phosphate is produced after purification and cleaning.

[0038] A feed pipe 2 is installed on the upper side wall of the evaporator 1, a discharge pipe 6 is installed on the lower side wall of the evaporator 1, a support frame 9 is installed on the lower end of the evaporator 1, a heater 4 for heating and evaporating lithium iron phosphate production wastewater is installed on the lower inner wall of the evaporator 1, the input end of the gas supply pipe 21 is installed on the upper side wall of the evaporator 1, a stirring mechanism for stirring the lithium iron phosphate production wastewater is provided at the bottom of the evaporator 1, a lifting and spraying mechanism for accelerating the evaporation of lithium iron phosphate production wastewater is provided inside the evaporator 1, and a drive mechanism for simultaneously powering the stirring mechanism and the lifting and spraying mechanism is provided inside the support frame 9.

[0039] The stirring mechanism includes a limiting cylinder 7, which is vertically installed at the center of the bottom of the evaporator 1. The upper end of the limiting cylinder 7 is located inside the evaporator 1, and the lower end of the limiting cylinder 7 passes through the evaporator 1 and is located inside the support frame 9. A rotating cylinder 11 is rotatably connected to the inner wall of the limiting cylinder 7. Several stirring blades 5 for stirring the lithium iron phosphate production wastewater at the bottom of the evaporator 1 are horizontally installed through the limiting cylinder 7 at the upper end of the side wall of the rotating cylinder 11. A toothed ring 8 for driving the rotating cylinder 11 to rotate is installed through the limiting cylinder 7 at the lower end of the side wall of the rotating cylinder 11.

[0040] The lifting and spraying mechanism includes a movable rod 20, which is vertically slidably connected to the inner wall of the rotating cylinder 11. The lower end of the movable rod 20 passes through the rotating cylinder 11 and is fitted with a fixed plate 26. The side wall of the fixed plate 26 is fitted with an installation frame 12 for driving the fixed plate 26 and the movable rod 20 to move up and down. The upper end of the movable rod 20 passes through the rotating cylinder 11 and is fitted with an elastic telescopic rod 3. The spring inside the elastic telescopic rod 3 is kept in a stretched state, causing the output end of the elastic telescopic rod 3 to retract. The output end of the elastic telescopic rod 3 is fitted with a bracket 24. The side of the bracket 24 away from the elastic telescopic rod 3 is fitted with an installation ring 25. Several fixed frames 22 for filling wastewater are installed on the upper end of the installation ring 25. Several drainage holes 23 for spraying wastewater are opened on the side wall of the fixed frame 22 near the elastic telescopic rod 3. The installation frame 12 is equipped with a detection component for detecting the evaporation of lithium iron phosphate production wastewater.

[0041] The detection component includes a controller 10, which is installed at the bottom of the support frame 9. A pressure sensor 27 for measuring the resistance of the bracket 24 to move downward is installed at the bottom of the mounting frame 12. The detection end of the pressure sensor 27 is in close contact with the upper end of the fixing plate 26.

[0042] As the water in the lithium iron phosphate production wastewater evaporates, the wastewater becomes more viscous. When the support 24 moves downward, the resistance from the wastewater increases, and the measurement value of the pressure sensor 27 also increases. The pressure sensor 27 sends the measurement value to the controller 10 in real time. When the measurement value of the pressure sensor 27 is greater than the set value, it indicates that the lithium iron phosphate production wastewater has reached the concentration standard. The controller 10 sends a signal to the motor 19 and the heater 4 to stop them and trigger an alarm, reminding the staff to output the concentrated lithium iron phosphate production wastewater from the evaporator 1.

[0043] Meanwhile, as the lithium iron phosphate production wastewater becomes thicker, the support 24 no longer enters the lithium iron phosphate production wastewater. When moving, the elastic telescopic rod 3 is stretched to prevent the fixed frame 22 from bearing the thick lithium iron phosphate production wastewater.

[0044] The driving mechanism includes a motor 19, which is installed at the lower end of the evaporator 1. A rotating rod 13 is vertically installed at the output end of the motor 19. The lower end of the rotating rod 13 is rotatably connected to the bottom of the support frame 9. A gear 18 that meshes with a gear ring 8 is installed on the upper side wall of the rotating rod 13. A reciprocating screw 14 is installed on the side wall of the rotating rod 13 below the gear 18. A moving block 15 is rotatably connected to the side wall of the reciprocating screw 14 by a thread. The end of the moving block 15 near the mounting frame 12 is installed on the side wall of the mounting frame 12.

[0045] When in use, the motor 19 is started. The output end of the motor 19 drives the rotating rod 13 to rotate. The rotating rod 13 drives the gear 18 and the reciprocating screw 14 to rotate. The gear 18 drives the gear ring 8 to rotate. The gear ring 8 drives the rotating cylinder 11 to rotate. The rotating cylinder 11 drives the stirring fan blade 5 to rotate, thereby stirring the lithium iron phosphate production wastewater at the bottom of the evaporator 1, making the lithium iron phosphate production wastewater heat evenly and easier to evaporate.

[0046] Under the action of the screw thread, the reciprocating screw 14 drives the moving block 15 to move up and down reciprocally. The moving block 15 drives the mounting frame 12 to move up and down reciprocally. The mounting frame 12 drives the fixing plate 26 to move. The fixing plate 26 drives the moving rod 20 to move up and down reciprocally along the inner wall of the rotating cylinder 11. The moving rod 20 drives the elastic telescopic rod 3 to move. The elastic telescopic rod 3 drives the bracket 24 to move. The bracket 24 drives the mounting ring 25 to move. The mounting ring 25 drives the fixing frame 22 to move. When moving downward, the fixing frame 22 is immersed in the lithium iron phosphate production wastewater. When moving upward, the fixing frame 22 supports the lithium iron phosphate production wastewater to move upward. During the movement, the lithium iron phosphate production wastewater is splashed downward through the drain hole 23 to accelerate the evaporation of the lithium iron phosphate production wastewater.

[0047] As the mounting frame 12 moves downward, the top of the mounting frame 12 and the upper end of the fixing plate 26 will squeeze the pressure sensor 27, causing the pressure sensor 27 to measure the resistance value of the bracket 24. As the water in the lithium iron phosphate production wastewater evaporates, the lithium iron phosphate production wastewater will become more viscous. When the bracket 24 moves downward, the resistance from the lithium iron phosphate production wastewater will increase, and the measurement value of the pressure sensor 27 will also increase. The pressure sensor 27 sends the measurement value to the controller 10 in real time. When the measurement value of the pressure sensor 27 is greater than the set value, it indicates that the lithium iron phosphate production wastewater has reached the concentration standard. The controller 10 sends a signal to the motor 19 and the heater 4 to stop the motor 19 and the heater 4 and alarm, reminding the staff to output the concentrated lithium iron phosphate production wastewater from the evaporator 1.

[0048] Meanwhile, as the lithium iron phosphate production wastewater becomes thicker, the support 24 no longer enters the lithium iron phosphate production wastewater. When moving, the elastic telescopic rod 3 is stretched to prevent the fixed frame 22 from bearing the thick lithium iron phosphate production wastewater.

[0049] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

Claims

1. A process for the resource utilization of wastewater from lithium iron phosphate production, characterized in that, Includes the following steps: Step 1: Add the lithium iron phosphate production wastewater into the evaporator (1) and convert the wastewater into clean steam through the evaporator (1); Step 2: The steam from Step 1 is transported to the interior of the twin-screw compressor (16) through the gas transmission pipe (21). The twin-screw compressor (16) performs work on the steam to raise its temperature to reach the temperature required in the lithium iron phosphate production process. Step 3: The steam heated in Step 2 is transported through the steam outlet pipe (17) to the reactor used for producing lithium iron phosphate, so that the high-temperature steam can serve as the heat source for the reactor and provide heat to the reactor. Step 4: The mother liquor concentrated due to water evaporation inside the evaporator (1) is recovered into the crude product storage tank, and lithium iron phosphate is produced after purification and cleaning. The evaporator (1) has a feed pipe (2) installed on the upper side wall, a discharge pipe (6) installed on the lower side wall, a support frame (9) installed on the lower end of the evaporator (1), a heater (4) for heating and evaporating lithium iron phosphate production wastewater installed on the lower inner wall of the evaporator (1), the input end of the gas transmission pipe (21) is installed on the upper side wall of the evaporator (1), a stirring mechanism for stirring lithium iron phosphate production wastewater is provided at the bottom of the evaporator (1), a lifting and spraying mechanism for accelerating the evaporation of lithium iron phosphate production wastewater is provided inside the evaporator (1), and a drive mechanism for providing power to both the stirring mechanism and the lifting and spraying mechanism is provided inside the support frame (9). The stirring mechanism includes a limiting cylinder (7), which is vertically installed at the center of the bottom of the evaporator (1). The upper end of the limiting cylinder (7) is located inside the evaporator (1), and the lower end of the limiting cylinder (7) passes through the evaporator (1) and is located inside the support frame (9). A rotating cylinder (11) is rotatably connected to the inner wall of the limiting cylinder (7). Several stirring blades (5) for stirring the lithium iron phosphate production wastewater at the bottom of the evaporator (1) are horizontally installed through the limiting cylinder (7) at the upper end of the side wall of the rotating cylinder (11). A toothed ring (8) for driving the rotating cylinder (11) to rotate is installed through the limiting cylinder (7) at the lower end of the side wall of the rotating cylinder (11). The lifting and spraying mechanism includes a movable rod (20), which is vertically slidably connected to the inner wall of the rotating cylinder (11). The lower end of the movable rod (20) passes through the rotating cylinder (11) and is fitted with a fixed plate (26). The side wall of the fixed plate (26) is fitted with a mounting frame (12) for driving the fixed plate (26) and the movable rod (20) to move up and down. The upper end of the movable rod (20) passes through the rotating cylinder (11) and is fitted with an elastic telescopic rod (3). The spring inside the elastic telescopic rod (3) is kept in a stretched state, so that the elastic... The output end of the telescopic rod (3) retracts, and a bracket (24) is installed at the output end of the elastic telescopic rod (3). An installation ring (25) is installed on the side of the bracket (24) away from the elastic telescopic rod (3). Several fixed frames (22) for injecting wastewater are installed on the upper end of the installation ring (25). Several drainage holes (23) for splashing wastewater are opened on the side wall of the fixed frame (22) near the elastic telescopic rod (3). A detection component for detecting the evaporation of lithium iron phosphate production wastewater is set inside the installation frame (12).

2. The process for resource utilization of lithium iron phosphate production wastewater according to claim 1, characterized in that, The detection component includes a controller (10) which is installed at the bottom of the support frame (9). A pressure sensor (27) for measuring the resistance of the bracket (24) to move downward is installed at the bottom of the mounting frame (12). The detection end of the pressure sensor (27) is in close contact with the upper end of the fixing plate (26).

3. The process for resource utilization of lithium iron phosphate production wastewater according to claim 1, characterized in that, The driving mechanism includes a motor (19), which is installed at the lower end of the evaporator (1). A rotating rod (13) is vertically installed at the output end of the motor (19). The lower end of the rotating rod (13) is rotatably connected to the bottom of the support frame (9). A gear (18) that meshes with a gear ring (8) is installed on the upper side wall of the rotating rod (13). A reciprocating screw (14) is installed on the side wall of the rotating rod (13) below the gear (18). A moving block (15) is rotatably connected to the side wall of the reciprocating screw (14) by a thread. The end of the moving block (15) near the mounting frame (12) is installed on the side wall of the mounting frame (12).

4. The process for resource utilization of lithium iron phosphate production wastewater according to claim 1, characterized in that, The bracket (24) has a rib installed on the side away from the elastic telescopic rod (3) at the lower end for supporting the bracket (24). The end of the rib close to the elastic telescopic rod (3) is installed at an angle downward at the output end of the elastic telescopic rod (3).

5. The process for resource utilization of lithium iron phosphate production wastewater according to claim 1, characterized in that, Both the inner wall of the limiting cylinder (7) and the inner wall of the rotating cylinder (11) are equipped with sealing rings to prevent wastewater leakage.

6. The process for resource utilization of lithium iron phosphate production wastewater according to claim 1, characterized in that, Both the evaporator (1) and the gas pipeline (21) are provided with heat insulation layers for heat preservation.

7. The process for resource utilization of lithium iron phosphate production wastewater according to claim 1, characterized in that, The stirring blade (5) is vertically provided with a cleaning rod for cleaning the heater (4) at the end away from the rotating cylinder (11), and the side wall of the cleaning rod is in close contact with the side wall of the heater (4).

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