A corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate

Abstract

The present invention relates to a corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate, and belongs to the technical field of electrolyte production. The sedimentation centrifugal production device of the present invention comprises a production box, wherein a sedimentation section is arranged inside the production box, a bearing seat 1 is arranged on the left side of the production box, a differential is installed on the left side of the bearing seat 1, the output end of the differential passes through the left side of the production box and is installed with a drum, a spiral pusher is installed inside the drum, a centrifugal filter shell is installed on the right side of the drum, a feed pipe is connected to the right side of the centrifugal filter shell, and the right end of the feed pipe passes through the inner wall of the production box and is installed with a bearing seat 2. In the present invention, solid-liquid separation is achieved by a drum, a screw conveyor, a feed pipe, a differential and a centrifugal filter shell, and the whole device has the advantages of compact structure, simple operation and high separation efficiency, which can meet the needs of large-scale production and improve production efficiency and product quality.

Description

Technical Field

[0001] The invention relates to the technical field of electrolyte production, in particular to a corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate. Background Art

[0002] With the rapid development of the battery industry, the demand for lithium hexafluorophosphate, as an important component of electrolyte, is increasing. The rapid development of the battery industry has brought about an increase in demand for lithium hexafluorophosphate. As an important component of electrolyte, lithium hexafluorophosphate plays a key role in battery manufacturing.

[0003] In the fine production process of lithium hexafluorophosphate, the sedimentation centrifugal production device will inject the lithium hexafluorophosphate suspension containing solid particles into the drum of the centrifugal filter shell. The high-speed rotating drum generates a strong centrifugal force, which causes the solid particles in the suspension to quickly settle to the drum wall under the action of centrifugal force, forming a dense sediment layer. At the same time, the clarified liquid is discharged through the overflow port or suction tube of the drum, realizing effective separation of solid and liquid.

[0004] In the production process of lithium hexafluorophosphate, the sedimentation separation of the product is a key step, which directly affects the quality and production efficiency of the product. The traditional sedimentation separation device has the problems of complex operation and low separation efficiency. The operating conditions of lithium hexafluorophosphate sedimentation separation are very bad. It is corroded by substances such as fluoride ions, which can easily lead to the thinning of the wall thickness of the centrifugal filter shell and eventually rupture. The sedimentation centrifuge has a high failure rate, which seriously restricts the stable production of the sedimentation centrifuge process. At the same time, frequent maintenance also increases production costs. It is difficult to meet the needs of large-scale production. Therefore, a corrosion-resistant sedimentation centrifuge production device for lithium hexafluorophosphate is proposed to solve the above problems. Summary of the invention

[0005] In order to make up for the above shortcomings, the present invention provides a corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate, aiming to improve the problems of complex operation and low separation efficiency of traditional sedimentation separation devices in the prior art.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: the present invention provides a corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate, including a production box, a sedimentation section is arranged inside the production box, a bearing seat 1 is arranged on the left side of the production box, a differential is installed on the left side of the bearing seat 1, the output end of the differential passes through the left side of the production box and is installed with a drum, a spiral pusher is installed inside the drum, a centrifugal filter shell is installed on the right side of the drum, a feed pipe is connected to the right side of the centrifugal filter shell, and the right end of the feed pipe passes through the inner wall of the production box and is installed with a bearing seat 2.

[0007] As a further description of the above technical solution: the left side of the bottom of the production box is connected to a liquid outlet pipe 1, and the right side of the bottom of the production box is connected to a liquid outlet pipe 2.

[0008] As a further description of the above technical solution: a discharge port is provided on the right side of the bottom of the production box.

[0009] As a further description of the above technical solution: the left end of the feed pipe is connected to the right side of the drum.

[0010] As a further description of the above technical solution: the bottoms of the bearing seat 1 and the bearing seat 2 are both fixedly connected with a fixing seat.

[0011] As a further description of the above technical solution: the surface of the centrifugal filter shell (8) is cured to form a hydrofluoric acid resistant composite coating, comprising the following steps:

[0012] T1: Add 2-6 parts of γ-glycidyloxypropyltrimethoxysilane and 100-150 parts of ultrafine molybdenum disulfide to 600-1000 parts of water, stir the reaction mixture at room temperature for 1-3 hours, filter, and dry to obtain γ-glycidyl molybdenum disulfide;

[0013] T2: Add 5-12 parts of γ-glycidyl ether-containing molybdenum disulfide, 20-40 parts of 4,4'-dimercaptodiphenyl ether, 5-10 parts of hexafluoropropylene dimer, 70-100 parts of water, and 2-5 parts of sodium hydroxide, and continue to stir the reaction mixture at 60-70°C for 30-50 minutes; then add 0.8-2.4 parts of potassium peroxide, and continue to stir at 60-70°C for 50-100 minutes to obtain a spray liquid;

[0014] T3: Then the first spraying is carried out. The process of the first spraying is as follows: spray the molybdenum disulfide slurry onto the inner surface of the centrifugal filter shell with a high-pressure spray gun, dry it naturally, and then dry it with 120-140°C hot air for 15-20 hours; then repeat the second and third spraying to form a hydrofluoric acid resistant composite coating.

[0015] As a further description of the above technical solution: the thickness of the hydrofluoric acid resistant composite coating is 10-20 microns.

[0016] Reaction mechanism

[0017] 1. The mechanism of the mercapto-epoxy reaction between γ-glycidyl molybdenum disulfide and 4,4'-dimercaptodiphenyl ether:

[0018] The epoxy group in γ-glycidyl molybdenum disulfide is easy to open due to the large ring strain. In the presence of nucleophiles such as thiol (-SH), the epoxy ring is opened to form a hydroxyl group and generate a new thioether bond.

[0019] 2. Mechanism of the thiol-ene addition reaction of hexafluoropropylene dimer and 4,4'-dimercaptodiphenyl ether:

[0020] The thiol-ene addition reaction proceeds via a free radical or ionic mechanism. In this reaction, the thiol acts as a nucleophile to attack the unsaturated carbon-carbon double bond on hexafluoropropylene. This reaction can be initiated by a photoinitiator to generate a free radical intermediate, which is then rapidly followed by a chain extension reaction.

[0021] Technical Effects

[0022] The corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate of the present invention has the following significant effects compared with the prior art:

[0023] 1. Improve corrosion resistance:

[0024] The introduced molybdenum disulfide has good chemical stability and low surface energy, which can effectively block the erosion of corrosive media such as hydrofluoric acid. The hexafluoroalkyl group provides additional water and oil resistance, further enhancing the corrosion resistance of the centrifuge material.

[0025] 2. Enhance mechanical properties:

[0026] The layered structure of molybdenum disulfide can form a lubricating layer in the centrifuge coating, reduce internal stress, and improve the flexibility and crack resistance of the coating. The added polymer components such as diphenyl ether can provide good adhesion and mechanical strength, ensuring the durability and stability of the centrifuge coating in daily use.

[0027] 3. The decanter centrifuge of the present invention reduces the failure rate, realizes continuous production, ensures stable production of the decanter centrifuge process, and reduces maintenance and production costs. It can meet the needs of large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of a corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate proposed by the present invention.

[0029] Legend: 1. Production box; 2. Sedimentation section; 3. Bearing seat 1; 4. Bearing seat 2; 5. Differential; 6. Drum; 7. Screw pusher; 8. Centrifugal filter shell; 9. Feed pipe; 10. Liquid outlet pipe 1; 11. Liquid outlet pipe 2; 12. Discharge port; 13. Fixed seat. DETAILED DESCRIPTION

[0030] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0031] Example 1

[0032] A corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate, comprising a production box 1, a sedimentation section 2 is arranged inside the production box 1, a bearing seat 3 is arranged on the left side of the production box 1, a differential 5 is installed on the left side of the bearing seat 3, the output end of the differential 5 passes through the left side of the production box 1 and is installed with a drum 6, a spiral pusher 7 is installed inside the drum 6, a centrifugal filter shell 8 is installed on the right side of the drum 6, a feed pipe 9 is connected to the right side of the centrifugal filter shell 8, and the right end of the feed pipe 9 passes through the inner wall of the production box 1 and is installed with a bearing seat 2 4;

[0033] Specifically, a sedimentation section 2 is provided inside the production box 1 to facilitate the sedimentation and separation of materials. A bearing seat 3 is provided on the left side of the production box 1, and its function is to support and fix the differential 5. The output end of the differential 5 extends to the left side of the production box 1 and is connected to a drum 6. The differential 5 controls the rotation speed of the drum 6 to achieve material separation. Screw pushers 7 are evenly installed inside the drum 6. The function of the screw pushers 7 is to push the material axially during the rotation of the drum 6 to further promote the sedimentation and separation of the material. A centrifugal filter shell 8 is installed on the right side of the drum 6. The centrifugal filter shell 8 is used for centrifugal filtration of the material to achieve solid-liquid separation. The right side of the centrifugal filter shell 8 is connected to a feed pipe 9. The function of the feed pipe 9 is to introduce the material into the device for processing. The right end of the feed pipe 9 passes through the inner wall of the production box 1, and a bearing seat 2 4 is installed outside the production box 1. The bearing seat 2 4 is mainly used to support and fix the feed pipe 9 to ensure its stable operation.

[0034] Reference Figure 1 The left side of the bottom of the production box 1 is connected to a liquid outlet pipe 10, the right side of the bottom of the production box 1 is connected to a liquid outlet pipe 2 11, and a discharge port 12 is opened on the right side of the bottom of the production box 1;

[0035] Specifically, a liquid outlet pipe 10 is connected to the bottom of the production box 1 to form a smooth liquid output channel, and the liquid outlet pipe 10 is responsible for effectively discharging the liquid substances generated in the production process, ensuring the smooth progress of the production process. A liquid outlet pipe 2 11 is also provided on the right side of the bottom of the production box 1, and works together with the liquid outlet pipe 10 to form a two-pronged liquid discharge. A discharge port 12 is opened on the right side of the bottom of the production box 1, and the discharge port 12 is mainly used to discharge lithium hexafluorophosphate solids generated in the production process.

[0036] Reference Figure 1 The left end of the feed pipe 9 is connected to the right side of the drum 6, and the bottoms of the bearing seat 1 3 and the bearing seat 2 4 are fixedly connected with a fixing seat 13;

[0037] Specifically, the left end of the feed pipe 9 is connected to the right side of the drum 6 to form a smooth material transmission channel, and is connected to the fixing seat 13 at the bottom of the bearing seat 1 3 and the bearing seat 2 4, ensuring the stability and durability of the entire device.

[0038] Working principle: the material enters the production box 1 through the feed pipe 9, settles in the sedimentation section 2, and then is further settled and separated in the drum 6 through the spiral pusher 7. The separated solid-liquid mixture is centrifugally filtered through the centrifugal filter shell 8 to achieve solid-liquid separation. The separated liquid is discharged through the liquid outlet pipe 10 and the liquid outlet pipe 2 11 for recycling, and the separated solid material is discharged through the discharge port 12. The whole device has the advantages of compact structure, simple operation and high separation efficiency, which can meet the needs of large-scale production and improve production efficiency and product quality.

[0039] The surface of the centrifugal filter shell (8) is cured to form a hydrofluoric acid resistant composite coating, comprising the following steps:

[0040] T1: Add 2 kg of γ-glycidyloxypropyltrimethoxysilane and 100 kg of ultrafine molybdenum disulfide to 600 kg of water, stir the reaction mixture at room temperature for 1 hour, filter, and dry to obtain γ-glycidyl molybdenum disulfide;

[0041] T2: Add 5kg of γ-glycidyl molybdenum disulfide, 20kg of 4,4'-dimercaptodiphenyl ether, 5kg of hexafluoropropylene dimer, 70kg of water, and 2kg of sodium hydroxide, and continue to stir the reaction mixture at 60°C for 30 minutes; then add 0.8kg of potassium peroxide, and continue to stir at 60°C for 50 minutes to obtain a spray liquid;

[0042] T3: Then the first spraying is carried out. The process of the first spraying is as follows: the molybdenum disulfide slurry is sprayed onto the inner surface of the centrifugal filter shell with a high-pressure spray gun, dried naturally, and then dried with 120°C hot air for 15 hours; then the second and third spraying are repeated to form a hydrofluoric acid-resistant composite coating.

[0043] The thickness of the hydrofluoric acid resistant composite coating is 10 microns.

[0044] Example 2

[0045] In this embodiment, except for the following technical solutions, other parts are the same as those in Embodiment 1:

[0046] The centrifugal filter shell (8) is cured to form a hydrofluoric acid resistant composite coating, comprising the following steps:

[0047] T1: Add 4 kg of γ-glycidyloxypropyltrimethoxysilane and 125 kg of ultrafine molybdenum disulfide to 800 kg of water, stir the reaction mixture at room temperature for 2 hours, filter, and dry to obtain γ-glycidyl molybdenum disulfide;

[0048] T2: Add 9kg of γ-glycidyl molybdenum disulfide, 30kg of 4,4'-dimercaptodiphenyl ether, 7.5kg of hexafluoropropylene dimer, 85kg of water, and 3.5kg of sodium hydroxide, and continue to stir the reaction mixture at 65°C for 40 minutes; then add 1.5kg of potassium peroxide and continue to stir at 65°C for 75 minutes to obtain a spraying liquid;

[0049] T3: Then the first spraying is carried out. The process of the first spraying is as follows: spray the molybdenum disulfide slurry onto the inner surface of the centrifugal filter shell with a high-pressure spray gun, dry it naturally, and then dry it with 130°C hot air for 17.5 hours; then repeat the second and third spraying to form a hydrofluoric acid-resistant composite coating.

[0050] The thickness of the hydrofluoric acid resistant composite coating is 15 microns.

[0051] Example 3

[0052] In this embodiment, except for the following technical solutions, other parts are the same as those in Embodiment 1:

[0053] The centrifugal filter shell (8) is cured to form a hydrofluoric acid resistant composite coating, comprising the following steps:

[0054] T1: Add 6 kg of γ-glycidyloxypropyltrimethoxysilane and 150 kg of ultrafine molybdenum disulfide to 1000 kg of water, stir the reaction mixture at room temperature for 3 hours, filter, and dry to obtain γ-glycidyl molybdenum disulfide;

[0055] T2: Add 12kg of γ-glycidyl molybdenum disulfide, 40kg of 4,4'-dimercaptodiphenyl ether, 10kg of hexafluoropropylene dimer, 100kg of water, and 5kg of sodium hydroxide, and continue to stir the reaction mixture at 70°C for 50 minutes; then add 2.4kg of potassium peroxide, and continue to stir at 70°C for 100 minutes to obtain a spraying liquid;

[0056] T3: Then the first spraying is carried out. The process of the first spraying is as follows: spray the molybdenum disulfide slurry onto the inner surface of the centrifugal filter shell with a high-pressure spray gun, dry it naturally, and then dry it with 140°C hot air for 20 hours; then repeat the second and third spraying to form a hydrofluoric acid-resistant composite coating.

[0057] The thickness of the hydrofluoric acid resistant composite coating is 20 microns.

[0058] Comparative Example 1

[0059] The centrifugal filter shell (8) is not subjected to curing treatment to form a hydrofluoric acid-resistant composite coating, and the rest is the same as in Example 1.

[0060] Comparative Example 2

[0061] No γ-glycidyl molybdenum disulfide was added, and the other steps were the same as in Example 1.

[0062] Detection Methods

[0063] The full immersion corrosion test was carried out in accordance with ASTM KG31-12A. The test temperatures were 27°C, 35°C and 40°C. The solutions selected were 3.5% NaCl solution and 3.5% NaCl+0.25% Na2S2O8 solution. The test time was 30 days. The results of the full immersion corrosion test are shown in the table below.

[0064] Data Sheet

[0065] sample Corrosion rate kg / m2.h Local corrosion depth μm Example 1 0.0045 7 Example 2 0.0042 7 Example 3 0.0038 5 Comparative Example 1 0.6552 34 Comparative Example 2 0.0322 12

[0066] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. 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 corrosion-resistant centrifugal sedimentation production device for lithium hexafluorophosphate, comprising a production box (1), characterized in that: The production box (1) is provided with a sedimentation section (2) inside, the left side of the production box (1) is provided with a bearing seat 1 (3), the left side of the bearing seat 1 (3) is installed with a differential (5), the output end of the differential (5) passes through the left side of the production box (1) and is installed with a drum (6), the inside of the drum (6) is installed with a spiral pusher (7), the right side of the drum (6) is installed with a centrifugal filter shell (8), the right side of the centrifugal filter shell (8) is connected with a feed pipe (9), the right end of the feed pipe (9) passes through the inner wall of the production box (1) and is installed with a bearing seat 2 (4); The surface of the centrifugal filter shell (8) is cured to form a hydrofluoric acid-resistant composite coating; The preparation of the hydrofluoric acid resistant composite coating comprises the following steps: T1: Add 2-6 parts of γ-glycidyloxypropyltrimethoxysilane and 100-150 parts of ultrafine molybdenum disulfide to 600-1000 parts of water, stir the reaction mixture at room temperature for 1-3 hours, filter, and dry to obtain γ-glycidyl molybdenum disulfide; T2: Add 5-12 parts of γ-glycidyl ether-containing molybdenum disulfide, 20-40 parts of 4,4'-dimercaptodiphenyl ether, 5-10 parts of hexafluoropropylene dimer, 70-100 parts of water, and 2-5 parts of sodium hydroxide, and continue to stir the reaction mixture at 60-70°C for 30-50 minutes; then add 0.8-2.4 parts of potassium peroxide, and continue to stir at 60-70°C for 50-100 minutes to obtain a spray liquid; T3: Then the first spraying is carried out. The process of the first spraying is as follows: spray the molybdenum disulfide slurry onto the inner surface of the centrifugal filter shell with a high-pressure spray gun, dry it naturally, and then dry it with 120-140°C hot air for 15-20 hours; then repeat the second and third spraying to form a hydrofluoric acid resistant composite coating.

2. A corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate according to claim 1, characterized in that: The left side of the bottom of the production box (1) is connected to a liquid outlet pipe 1 (10), and the right side of the bottom of the production box (1) is connected to a liquid outlet pipe 2 (11).

3. A corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate according to claim 1, characterized in that: A discharge port (12) is provided on the right side of the bottom of the production box (1).

4. A corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate according to claim 1, characterized in that: The left end of the feed pipe (9) is connected to the right side of the drum (6).

5. A corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate according to claim 1, characterized in that: The bottoms of the bearing seat 1 (3) and the bearing seat 2 (4) are both fixedly connected with a fixing seat (13).

6. A corrosion-resistant sedimentation centrifugal production device for lithium hexafluorophosphate according to claim 1, characterized in that: The thickness of the hydrofluoric acid resistant composite coating is 10-20 microns.

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