Iron phosphate particle size control device

Abstract

The utility model discloses an iron phosphate particle size control device, which belongs to the field of iron phosphate preparation and comprises a pulping kettle, a metering tank and an aging kettle. The pulping kettle, the metering tank and the aging kettle are sequentially connected through pipelines; a liquid level control device is arranged on the metering tank; a flow control device and a temperature control device are arranged outside the aging kettle; a first control valve is arranged on a pipeline for connecting the aging kettle and the metering tank; a second control valve is arranged on the pipeline between the aging kettle and the flow control device; the aging kettle is connected with a third control valve; the liquid level control device is electrically connected with the first control valve, and when the first control valve receives the release signal, the first control valve is opened; when the liquid level control device recognizes that the liquid level in the metering tank reaches a liquid level set value, the first control valve is controlled to be closed. The particle size control device is simple in structure, the control device is added on the basis of an original preparation device, the purpose of controlling the particle size is achieved, and the use requirements of various manufacturers are met.

Description

Technical Field

[0001] The utility model belongs to the field of iron phosphate preparation, and particularly relates to an iron phosphate particle size control device. Background Art

[0002] The compaction density of lithium iron phosphate products is a key factor in determining the energy density of a battery cell and has a significant impact on the battery's ultimate performance. Simply put, compaction density refers to the degree to which the active material is packed within a unit volume, typically expressed in grams per cubic centimeter (g / cm³). The physical properties of lithium iron phosphate itself have a fundamental influence on its compaction density. Particle size distribution, shape, and crystallinity are all directly related to compaction density. For example, a smaller particle size promotes closer contact between particles, thereby increasing compaction density. However, excessively small particle size may cause significant agglomeration, reducing compaction efficiency. Therefore, the appropriate particle size of lithium iron phosphate has a substantial impact on its performance.

[0003] The current mainstream process for preparing ferric phosphate generally utilizes a liquid-phase oxidation co-precipitation method. The specific method is as follows: ferrous sulfate is used as the iron source, a phosphorus-containing material such as phosphoric acid or ammonium dihydrogen phosphate is used as the phosphorus source, and hydrogen peroxide is used as the oxidant. In a reactor, a phosphorus source solution and hydrogen peroxide are mixed in a predetermined ratio. An iron source solution is then added to react. Finally, sodium hydroxide is added as a precipitant to adjust the pH of the solution, causing the precipitation of ferric phosphate (referred to herein as crude ferric phosphate). The crude product is heated and aged for a period of time to produce ferric phosphate dihydrate. The precipitate is then filtered, washed, and calcined to obtain the final ferric phosphate product.

[0004] 2H + +2Fe 2+ +H2O2→2Fe 3+ +2H2O

[0005] 6FeSO4+3H2O2→2Fe(SO4)3+2Fe(OH)3

[0006] 2Fe 3+ +2(HPO4) 2- →2FePO4↓+2H +

[0007] Generally speaking, qualified ferric phosphate products can be produced according to the above process, but the product acceptance area is small. This is also the problem that the present invention attempts to solve, that is, to achieve the purpose of controlling the particle size of the ferric phosphate product.

[0008] In the prior art, Chinese patent publication number: CN112441626A, publication date: March 5, 2021, discloses a method and equipment for the graded preparation of lithium battery positive electrode material precursors, including a water flow grading trough, the water flow grading trough is a long trough, one end of the long trough is used to pass the secondary slurry coarse product, and the other end is used to discharge the micropowder slurry. A number of vertical plates are also arranged inside the long trough, and the height of the vertical plates increases successively to perform multi-stage separation of the secondary slurry coarse product to obtain precursor particle slurry of various particle sizes.

[0009] However, the above existing technologies have obvious deficiencies:

[0010] 1. Raw materials with various particle sizes need to be separated and circulated step by step, and the particle size of the raw materials cannot be uniformly controlled.

[0011] 2. The preparation process requires multiple cycles, which reduces the preparation efficiency. Summary of the Invention

[0012] The purpose of the utility model is to overcome the problem that the iron phosphate produced by the existing technology can only obtain a particle size range of 2 to 4 microns, which cannot meet the production needs of different manufacturers. At the same time, the raw materials cannot be prepared in one go and need to be separated step by step, and the preparation process is cumbersome. An iron phosphate particle size control device is provided to solve the problem that the iron phosphate particle size cannot be changed in the production process of the existing technology and the preparation process is complicated and the production efficiency is low, thereby meeting the production needs of various manufacturers.

[0013] In order to achieve the above purpose, the technical solution adopted by the present utility model is as follows:

[0014] A device for controlling the particle size of ferric phosphate, characterized in that: it includes a beating kettle, a metering tank and an aging kettle; the beating kettle, metering tank and aging kettle are connected in sequence by pipelines; a liquid level control device is provided on the metering tank; a flow control device and a temperature control device are provided outside the aging kettle; a first control valve is provided on the pipeline connecting the aging kettle and the metering tank; a second control valve is provided on the pipeline between the aging kettle and the flow control device; a third control valve is connected to the aging kettle; the liquid level control device is electrically connected to the first control valve, and when the first control valve receives a release signal, the first control valve is opened; when the liquid level control device identifies that the liquid level in the metering tank has reached the liquid level set value, the first control valve is controlled to be closed.

[0015] The flow control device is electrically connected to the second control valve. When the second control valve receives a release signal, the second control valve is opened. When the flow control device identifies that the flow reaches a preset release flow, the second control valve is controlled to close.

[0016] The temperature control device is electrically connected to the third control valve. When the third control valve receives a temperature increase signal, the third control valve is opened. When the temperature control device recognizes that the temperature reaches the set temperature, the third control valve is controlled to close.

[0017] The beating kettle, the metering tank and the aging kettle are all provided with stirring devices.

[0018] A pressure valve and a pressure pump are provided between the beating kettle and the metering tank.

[0019] The discharge port of the aging kettle is provided with a pressure valve and a pressure pump.

[0020] The first control valve, the second control valve and the third control valve are all solenoid valves.

[0021] A heat preservation device is provided outside the aging kettle.

[0022] The temperature control device sets the temperature to 90°C.

[0023] The advantages of adopting the utility model are:

[0024] 1. Compared with the prior art which requires step-by-step separation, the present invention increases the control of the liquid level during the release of ferric phosphate and the flow rate during the release of phosphoric acid, effectively controls the reaction process, and accurately controls the particle size of ferric phosphate.

[0025] Second, the preparation process of the utility model is simple, and the required iron phosphates of various particle sizes can be prepared separately, thereby improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the iron phosphate particle size control device of the present invention.

[0027] The following are marked in the figure: 1. beating kettle, 2. metering tank, 3. aging kettle, 4. liquid level control device, 5. flow control device, 6. first control valve, 7. second control valve, 8. pressure valve, 9. pressure pump, 10. stirring device, 11. insulation device, 12. temperature controller, 13. third control valve. DETAILED DESCRIPTION

[0028] Example 1

[0029] This embodiment further illustrates the structure and principle of the present invention with reference to the accompanying drawings:

[0030] A device for controlling the particle size of ferric phosphate comprises a beating kettle 1, a metering tank 2 and an aging kettle 3; the beating kettle 1, metering tank 2 and aging kettle 3 are connected in sequence by pipelines; a liquid level control device 4 is provided on the metering tank 2; a flow control device 5 and a temperature control device 6 are provided outside the aging kettle 1; a first control valve 6 is provided on the pipeline connecting the aging kettle 3 and the metering tank 2; a second control valve 7 is provided on the pipeline between the aging kettle 3 and the flow control device 5; a third control valve 13 is connected to the aging kettle 3; the liquid level control device 4 is electrically connected to the first control valve 6, and when the first control valve 6 receives a release signal, the first control valve 6 is opened; when the liquid level control device 4 identifies that the liquid level in the metering tank 2 has reached the liquid level set value, the first control valve 6 is controlled to be closed.

[0031] The flow control device 5 is electrically connected to the second control valve 7. When the second control valve 7 receives a release signal, the second control valve 7 is opened. When the flow control device 5 identifies that the flow reaches a preset release flow, the second control valve 5 is controlled to close.

[0032] The temperature control device 12 is electrically connected to the third control valve 13. When the third control valve 13 receives a temperature increase signal, the third control valve 13 is opened. When the temperature control device 12 recognizes that the temperature reaches the set temperature, the third control valve 13 is controlled to be closed.

[0033] A stirring device 10 is provided inside the beating kettle 1 , the metering tank 2 and the aging kettle 3 .

[0034] A pressure valve 8 and a pressure pump 9 are provided between the beating kettle 1 and the metering tank 2 .

[0035] The discharge port of the aging kettle 3 is provided with a pressure valve 8 and a pressure pump 9.

[0036] The first control valve 6 , the second control valve 7 and the third control valve 13 are all solenoid valves.

[0037] A heat preservation device 11 is provided outside the aging kettle 3 .

[0038] The temperature control device 12 sets the temperature to 90°C.

[0039] Example 2

[0040] like Figure 1As shown, a device for controlling the particle size of iron phosphate is shown. The crude iron phosphate solid and water are poured into a beating kettle 1, stirred evenly by a stirring device, and then pressed into a metering tank 2. The stirring device in the metering tank 2 maintains a stirring state to prevent the iron phosphate from depositing. When the first control valve 6 receives a release signal, the first control valve 6 opens, and the liquid level control device 4 monitors the liquid level. At the same time, the second control valve 7 receives a release signal, the second control valve 7 opens, and the flow control device 5 monitors the phosphoric acid flow. When the iron phosphate slurry in the metering tank reaches a preset release amount, the liquid level control device 4 starts to control the Close the first control valve 6; at the same time, when the phosphoric acid flow reaches a preset amount, the flow control switch 5 is started and the second control valve 7 is closed; the slurry entering the aging kettle 3 is released and stirred evenly, and the third control valve 13 is opened to release water vapor and heat it to 90°C. When heated to 90°C, the temperature control device 12 controls the closure of the third control valve 13, and the aging kettle is continuously stirred and kept warm at 90°C until the material turns white. The remaining crude slurry is then added to continue the reaction. After all the materials turn white, the temperature is kept warm for 3 hours. After the insulation is completed, the temperature is cooled to room temperature, the product is filtered, and then dried and calcined before being sent for inspection.

[0041] The particle size of ferric phosphate is controlled to obtain a smaller particle size of the product.

[0042] Crude product aging process: Add 5 times its weight of water to the crude ferric phosphate obtained in the previous process to disperse it, then transfer it to the aging kettle 3, add 0.2 equivalents of 85% phosphoric acid (the molar number of ferrous sulfate added is 1 equivalent), and heat it to 90°C until the material turns white, and then keep it warm for 3 hours; after the insulation is completed, cool it to room temperature, filter the product, and then dry and calcine it before sending it for inspection.

[0043] Table 1

[0044]

[0045] Reaction mode with larger product particle size

[0046] Crude product aging process: Add 5 times its weight of water to the crude ferric phosphate obtained in the previous process to disperse it. After stirring evenly, transfer a portion of the slurry into the aging kettle 3, add 0.2 equivalents of 85% phosphoric acid (the molar number of ferrous sulfate fed is 1 equivalent), and heat it to 90°C until the material turns white. Then add the remaining crude product slurry to continue the reaction. After all the materials turn white, keep the temperature for 3 hours; after the insulation is completed, cool to room temperature, filter the product, dry and calcine it, and then send it for inspection.

[0047] Table 2

[0048]

[0049] It can be seen that in the crude product aging process, by controlling the amount of crude ferric phosphate slurry added, ferric phosphate products with different particle sizes can be obtained, thereby achieving the purpose of controlling the product particle size.

[0050] The liquid level control device, flow control device, stirring device and heat preservation device are conventional control devices in this field.

Claims

1. A device for controlling the particle size of iron phosphate, characterized in that: The invention comprises a beating kettle (1), a metering tank (2) and an aging kettle (3); the beating kettle (1), the metering tank (2) and the aging kettle (3) are connected in sequence by pipelines; a liquid level control device (4) is provided on the metering tank (2); a flow control device (5) and a temperature control device (12) are provided outside the aging kettle (3); a first control valve (6) is provided on the pipeline connecting the aging kettle (3) and the metering tank (2); a second control valve (7) is provided on the pipeline between the aging kettle (3) and the flow control device (5); a third control valve (13) is connected to the aging kettle (3); the liquid level control device (4) is electrically connected to the first control valve (6) and is used to control the opening and closing of the first control valve (6).

2. The device for controlling the particle size of iron phosphate according to claim 1, wherein: The flow control device (5) is electrically connected to the second control valve (7) and is used to control the opening and closing of the second control valve (7).

3. The device for controlling the particle size of iron phosphate according to claim 1, wherein: The temperature control device (12) is electrically connected to the third control valve (13) and is used to control the opening and closing of the third control valve.

4. The device for controlling the particle size of iron phosphate according to claim 1, wherein: A stirring device (10) is provided inside the beating kettle (1), the metering tank (2) and the aging kettle (3).

5. The device for controlling the particle size of iron phosphate according to claim 1, wherein: A pressure valve (8) and a pressure pump (9) are provided between the beating kettle (1) and the metering tank (2).

6. The device for controlling particle size of iron phosphate according to claim 1, wherein: The discharge port of the aging kettle (3) is provided with a pressure valve (8) and a pressure pump (9).

7. The device for controlling the particle size of iron phosphate according to claim 1, wherein: The first control valve (6), the second control valve (7) and the third control valve (13) are all solenoid valves.

8. The device for controlling particle size of iron phosphate according to claim 1, wherein: A heat preservation device (11) is provided outside the aging kettle (3).

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