A drying device for lithium tetrafluoroborate

Abstract

The utility model belongs to compound drying equipment technical field, concretely is a kind of lithium tetrafluoroborate drying device, including the neutralization reaction kettle, centrifugal filter and vacuum rake dryer that are sequentially communicated, the inside of neutralization reaction kettle is provided with stirrer, and the bottom of neutralization reaction kettle is equipped with material flow pipe;Centrifugal filter is communicated with neutralization reaction kettle by material flow pipe, and detachably connected with filter core in centrifugal filter, and the bottom of centrifugal filter is equipped with discharge pipe;Vacuum rake dryer is communicated with centrifugal filter by discharge pipe, and the inside of vacuum rake dryer is equipped with stirring shaft, and it is provided with advancing type stirring paddle and arc stirring paddle on stirring shaft, and the bottom of vacuum rake dryer is equipped with discharge port.The common effect of centrifugal filter and vacuum rake dryer not only effectively solves the corrosion problem of fluorine-containing compound to equipment in drying process, but also avoids the thermal decomposition risk of lithium tetrafluoroborate under high temperature, provides reliable path for high-quality large-scale production of lithium tetrafluoroborate.

Description

Technical Field

[0001] This utility model belongs to the technical field of compound drying equipment, specifically a drying device for lithium tetrafluoroborate. Background Technology

[0002] As a lithium-ion battery electrolyte, lithium tetrafluoroborate (LiBF4) requires extremely high purity, especially with strict limitations on moisture content, to ensure the electrochemical stability and safety of the battery system. Currently, the synthesis of LiBF4 mainly employs two process routes: the aqueous solution method and the gas-solid reaction method. The aqueous solution method uses hydrofluoric acid, boric acid, and lithium carbonate as raw materials. The reaction process is complex, involving multiple steps, and carries a high degree of risk. Furthermore, solid melting easily occurs during the subsequent drying process, severely affecting the dehydration effect and resulting in a final product purity that fails to meet the requirements of high-end applications. The gas-solid reaction method relies on high-temperature conditions, placing high demands on equipment materials and process control. It also suffers from low reaction efficiency and difficulty in large-scale continuous production. It is worth noting that both synthesis routes face a common process bottleneck—difficulty in drying. When LiBF4 is heated or exposed to air and moisture, it easily undergoes a decomposition reaction, generating corrosive gases such as boron trifluoride (BF3) and hydrogen fluoride (HF). This not only damages drying equipment but also significantly increases production and maintenance costs, hindering the realization of continuous production capabilities. Summary of the Invention

[0003] To address the problems mentioned above, this invention provides a drying device for lithium tetrafluoroborate, which solves the problem of easy decomposition during the industrial drying process of lithium tetrafluoroborate.

[0004] The present invention adopts the following technical solution:

[0005] A drying apparatus for lithium tetrafluoroborate includes a neutralization reactor, a centrifugal filter, and a vacuum rake dryer connected in sequence, wherein:

[0006] The neutralization reactor is equipped with a material inlet pipe and a solid feeder at the top, an agitator inside, and a material flow pipe at the bottom.

[0007] The centrifugal filter is connected to the neutralization reactor through a material flow pipe. The centrifugal filter has a detachable filter element inside and a discharge pipe at the bottom.

[0008] The vacuum rake dryer is connected to the centrifugal filter through the discharge pipe. The vacuum rake dryer is equipped with a stirring shaft inside, which is driven to rotate by a power unit. The stirring shaft is equipped with a propulsion stirring paddle and an arc-shaped stirring paddle. The bottom of the vacuum rake dryer is equipped with a discharge port.

[0009] Furthermore, the arc-shaped impeller is located on the periphery of the propulsion impeller.

[0010] Furthermore, the arc-shaped impeller includes stirring rods spaced apart along the stirring shaft and perpendicular to the stirring shaft, and two arc-shaped stirring blades are arranged between two adjacent stirring rods. The two arc-shaped stirring blades are located on opposite sides of the stirring shaft, and the arc-shaped stirring blades surround the propulsion impeller.

[0011] Furthermore, the gap between the arc-shaped stirring blades and the inner wall of the vacuum rake dryer is 1~2cm.

[0012] Furthermore, the propulsion impeller includes helical blades wound axially around an agitator shaft, the helical blades being used to propel the fluid axially.

[0013] Furthermore, the vacuum rake dryer is equipped with a vacuum port and a vacuum gauge.

[0014] Furthermore, the vacuum rake dryer has a heating medium inlet on its side wall.

[0015] Furthermore, a material outlet valve is installed at the bottom of the neutralization reactor, and the material outlet valve is connected to the material flow pipe.

[0016] Furthermore, a discharge valve is provided at the bottom of the centrifugal filter, and the discharge valve is connected to the discharge pipe.

[0017] Furthermore, the filtration accuracy of the filter element is 0.3µm-0.5µm.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] (1) This application constructs a highly efficient integrated closed continuous operation system by sequentially connecting a neutralization reactor, a centrifugal filter, and a vacuum rake dryer. The neutralization reactor achieves sealed, uniform mixing, and efficient reaction of raw materials through the cooperation of a top solid feeder and an internal agitator. The centrifugal filter is equipped with a removable filter element, which realizes efficient connection between solid-liquid separation and purification, and prepares high-quality wet materials for the subsequent drying process. The vacuum rake dryer connected to the centrifugal filter provides a vacuum environment, enabling low-temperature drying in a vacuum environment, completely avoiding the problem of material melting due to heat. Moreover, its internal structure adopts a combination of propulsion agitator and arc-shaped agitator, which simultaneously realizes the functions of stirring, propulsion, and tumbling of materials, forming a strong internal circulation within the tank, effectively avoiding the problem of easy clumping during drying.

[0020] (2) By combining a propeller-type agitator and an arc-shaped agitator on the stirring shaft, the system forms a strong axial and radial composite flow field during the drying process, effectively breaking up material agglomeration and preventing lithium tetrafluoroborate from clumping during drying. The resulting product is a uniform and loose solid powder that can meet subsequent usage requirements without mechanical crushing, further simplifying the process. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 An overall structural diagram of a lithium tetrafluoroborate drying apparatus provided in an embodiment of this application;

[0023] Figure 2 A structural diagram of a vacuum rake dryer for a lithium tetrafluoroborate drying apparatus provided in an embodiment of this application;

[0024] Wherein: 1-Neutralization reactor, 11-Material inlet pipe, 12-Solid feeder, 13-Agitator, 14-Material flow pipe, 15-Material outlet valve, 2-Centrifugal filter, 21-Filter element, 22-Discharge pipe, 23-Discharge valve, 3-Vacuum rake dryer, 31-Agitator shaft, 32-Power unit, 33-Propeller agitator, 331-Helical blade, 34-Arc-shaped agitator, 341-Agitator rod, 342-Arc-shaped agitator blade, 35-Discharge port, 36-Vacuum extraction port, 37-Vacuum gauge, 38-Heating medium inlet. Detailed Implementation

[0025] The technical solutions in 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 protection scope of the present invention.

[0026] The following is in conjunction with the appendix Figure 1 To be continued Figure 2 The present invention will be described in detail with specific embodiments.

[0027] See Figures 1 to 2This utility model provides a drying device for lithium tetrafluoroborate, comprising a neutralization reactor 1, a centrifugal filter 2, and a vacuum rake dryer 3 connected in sequence. The neutralization reactor 1 has a material inlet pipe 11 and a solid feeder 12 at its top, a stirrer 13 inside, and a material flow pipe 14 at its bottom. The centrifugal filter 2 is connected to the neutralization reactor 1 via the material flow pipe 14, and a filter element 21 is detachably connected inside the centrifugal filter 2. A discharge pipe 22 is located at the bottom of the centrifugal filter 2. The vacuum rake dryer 3 is connected to the centrifugal filter 2 via the discharge pipe 22. A stirring shaft 31 is located inside the vacuum rake dryer 3, driven to rotate by a power device 32. A propeller-type stirring paddle 33 and an arc-shaped stirring paddle 34 are mounted on the stirring shaft 31. A discharge port 35 is located at the bottom of the vacuum rake dryer 3. This application constructs a highly efficient, integrated, closed-loop continuous operation system by sequentially connecting the neutralization reactor 1, the centrifugal filter 2, and the vacuum rake dryer 3. This design fundamentally solves the problem of lithium tetrafluoroborate hydrolysis caused by exposure to air in traditional preparation processes, effectively suppresses the generation of corrosive gases BF3 and HF, significantly improves product purity, greatly reduces equipment corrosion, extends equipment life, and lays a solid foundation for large-scale continuous production.

[0028] Specifically, see Figure 1 The neutralization reactor 1, through the solid feeder 12 at the top and the internal agitator 13, achieves closed-loop feeding, uniform mixing, and efficient reaction of raw materials. The centrifugal filter 2 is equipped with a removable filter element 21, which efficiently connects solid-liquid separation and purification, and prepares high-quality wet material for the subsequent drying stage. The vacuum rake dryer 3, connected to the centrifugal filter 2, provides a vacuum environment, enabling low-temperature drying and completely avoiding the problem of material melting due to heat. Furthermore, the vacuum rake dryer 3 employs a combination of a propeller-type agitator 33 and an arc-shaped agitator 34, simultaneously achieving stirring, propulsion, and tumbling of the material, forming a strong internal circulation within the tank and effectively preventing clumping during drying.

[0029] Furthermore, the arc-shaped agitator 34 is located around the propeller agitator 33. Specifically, the propeller agitator 33 is located at the center and is mainly responsible for generating strong axial thrust to ensure continuous axial movement of the material, while the arc-shaped agitator 34 is arranged around it, which can generate radial and axial flows. The radial flow is mainly responsible for generating shear force to break bubbles and droplets, while the axial flow is mainly responsible for promoting continuous up-and-down circulation of the material in the tank to achieve thorough mixing of the material. The above structure not only ensures stable material conveying but also ensures that all materials are uniformly stirred, effectively eliminating drying dead zones.

[0030] For further details, please refer to [link / reference]. Figure 2The arc-shaped stirring paddle 34 includes stirring rods 341 spaced apart along the stirring shaft 31 and perpendicular to the stirring shaft 31. Two arc-shaped stirring blades 342 are arranged between two adjacent stirring rods 341. The two arc-shaped stirring blades 342 are located on opposite sides of the stirring shaft 31 and surround the propeller-type stirring paddle 33. The arc-shaped stirring blades 342 distributed on both sides of the stirring shaft 31 and surrounding the propeller-type stirring paddle 33 enable the stirring range to cover most of the area except for the central conveying channel. This structure can fully cut, tumble, and mix the material, continuously renew the material layer in contact with heat, greatly improve heat transfer efficiency and drying uniformity, and effectively prevent local overheating or agglomeration. Specifically, the arc-shaped stirring blades 342 of the arc-shaped stirring paddle 34 form a smooth curved surface, and the cross-section of the arc-shaped stirring blades 342 fits the tank body. This allows the arc-shaped stirring blades 342 to generate a composite flow pattern combining radial and axial flow when rotating. The radial flow component provides the necessary shear force, effectively breaking up and crushing the initially formed material aggregates and droplets; while the axial flow component promotes the vertical circulation of materials within the tank. Simultaneously, the main function of the centrally located propeller-type stirring paddle 33 is to generate a strong, unidirectional axial mainstream, forcibly pushing the material from one end to the other, forming a large circulation throughout the entire tank. This application, through the combined action of the arc-shaped stirring paddle 34 and the propeller-type stirring paddle 33, forms a strong internal circulation within the tank, creating a vigorous and dead-angle-free turbulent field. Energy is efficiently used for full-tank circulation and mixing, resulting in extremely high mixing efficiency. This avoids product purity reduction caused by incomplete drying or localized overheating decomposition, ensuring the high purity and high quality of the final lithium tetrafluoroborate product.

[0031] Furthermore, the gap between the arc-shaped stirring blade 342 and the inner wall of the vacuum rake dryer 3 is 1-2 cm. This gap is sufficient to effectively scrape off viscous or semi-molten materials adhering to the inner wall, preventing thermal decomposition, coking, or scaling caused by long-term retention, and ensuring continuous and efficient heat transfer. At the same time, this gap also avoids direct contact and friction between the arc-shaped stirring blade 342 and the inner wall, ensuring operational safety and reducing power loss and equipment wear. This is an important design feature for achieving stable, low-energy-consumption, long-term operation.

[0032] For further details, please refer to [link / reference]. Figure 2 The propulsion impeller 33 includes helical blades 331 wound axially around the stirring shaft 31. The helical blades 331 are used to axially propel the fluid. The helical blades 331 are one of the most effective structures for achieving axial propulsion. When the continuous swirling inclined surface rotates, it can apply a stable and continuous unidirectional thrust to the material, conveying the material evenly like a screw. At the same time, the helical blades also perform preliminary mixing of the material during propulsion, and together with the outer arc-shaped stirring blades 342, they create an efficient and uniform drying environment.

[0033] This application employs an integrated solution combining a centrifugal filter and a vacuum rake dryer, significantly improving the synthesis and drying efficiency of lithium tetrafluoroborate. The centrifugal filtration process after neutralization initially removes moisture from the product, providing a higher-purity intermediate for subsequent processes. The vacuum rake dryer, by providing a high-vacuum and controllable heating stirring environment, achieves efficient dehydration of lithium tetrafluoroborate aqueous solution under low-temperature conditions. This drying process can be sustained at 80°C for 8 hours, ultimately resulting in a product moisture content below 50 ppm, successfully avoiding the decomposition problem of lithium tetrafluoroborate caused by high temperatures. Furthermore, by combining a propeller-type stirring paddle and an arc-shaped stirring paddle on the stirring shaft, the system generates a strong axial and radial composite flow field during the drying process, effectively breaking up material agglomeration and preventing lithium tetrafluoroborate from clumping during drying. The resulting product is a uniform, loose solid powder that meets subsequent usage requirements without the need for mechanical crushing, further simplifying the process flow.

[0034] For further details, please refer to [link / reference]. Figure 2 The vacuum rake dryer 3 is equipped with a vacuum extraction port 36 and a vacuum gauge 37. The vacuum extraction port 36 is responsible for establishing and maintaining the required low-pressure environment, thereby significantly reducing the boiling point of the material and achieving low-temperature, high-efficiency drying. This fundamentally prevents lithium tetrafluoroborate from melting or decomposing at high temperatures. The vacuum gauge 37 is used to monitor the vacuum level in the drying chamber in real time and accurately, providing key data for process control, ensuring the stability and reproducibility of the drying process conditions, and directly guaranteeing that the purity and moisture content of the final product meet the standards.

[0035] Furthermore, the side wall of the vacuum rake dryer 3 is equipped with a heating medium inlet 38 to provide a stable and controllable heat source for the drying process, effectively preventing the material from deteriorating due to local overheating, while improving the thermal energy utilization efficiency and operational safety of the entire system.

[0036] Furthermore, a material outlet valve 15 is provided at the bottom of the neutralization reactor 1, which is connected to the material flow pipe 14. A discharge valve 23 is provided at the bottom of the centrifugal filter 2, which is connected to the discharge pipe 22. To ensure smooth material transfer in the closed system, material outlet valves 15 and 23 are respectively provided at the bottom of the neutralization reactor 1 and the centrifugal filter 2. The design of these valves realizes physical isolation and controllable connection between the units, enabling the three core processes of front-end reaction, mid-stage filtration, and rear-stage drying to operate independently and seamlessly connect. This not only completely eliminates the risk of material contact with air during transfer but also lays a solid foundation for achieving fully automated and continuous operation.

[0037] Furthermore, the filter element 21 has a filtration accuracy of 0.3µm-0.5µm. This accuracy is sufficient to effectively trap fine solid particles and potential crystal nuclei impurities, ensuring that the intermediate product entering the drying process has extremely high solid phase purity.

[0038] This application, through the synergistic effect of neutralization centrifugal filtration and high-vacuum rake drying system, not only effectively solves the problem of corrosion of equipment by fluorinated compounds during the drying process, but also avoids the risk of thermal decomposition of lithium tetrafluoroborate at high temperatures. Thus, while improving product purity and process stability, it significantly improves industrial production efficiency and reduces operating costs, providing a reliable path for the high-quality, large-scale production of lithium tetrafluoroborate.

[0039] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A drying apparatus for lithium tetrafluoroborate, characterized in that, It includes a neutralization reactor, a centrifugal filter, and a vacuum rake dryer connected in sequence, wherein: The neutralization reactor is equipped with a material inlet pipe and a solid feeder at the top, a stirrer inside, and a material flow pipe at the bottom. The centrifugal filter is connected to the neutralization reactor through the material flow pipe. The centrifugal filter has a filter element that can be detachably connected inside. The centrifugal filter has a discharge pipe at the bottom. The vacuum rake dryer is connected to the centrifugal filter through the discharge pipe. The vacuum rake dryer is equipped with a stirring shaft inside, which is driven to rotate by a power device. The stirring shaft is equipped with a propulsion stirring paddle and an arc-shaped stirring paddle. The bottom of the vacuum rake dryer is equipped with a discharge port.

2. The drying apparatus for lithium tetrafluoroborate according to claim 1, characterized in that, The arc-shaped agitator is located on the periphery of the propulsion agitator.

3. The drying apparatus for lithium tetrafluoroborate according to claim 2, characterized in that, The arc-shaped stirring paddle includes stirring rods spaced apart along the stirring shaft and perpendicular to the stirring shaft. Two arc-shaped stirring blades are arranged between two adjacent stirring rods. The two arc-shaped stirring blades are located on opposite sides of the stirring shaft and surround the propulsion stirring paddle.

4. The drying apparatus for lithium tetrafluoroborate according to claim 3, characterized in that, The gap between the arc-shaped stirring blade and the inner wall of the vacuum rake dryer is 1~2cm.

5. The drying apparatus for lithium tetrafluoroborate according to claim 1, characterized in that, The propulsion impeller includes helical blades wound axially around the stirring shaft, the helical blades being used to propel fluid axially.

6. The drying apparatus for lithium tetrafluoroborate according to claim 1, characterized in that, The vacuum rake dryer is equipped with a vacuum port and a vacuum gauge.

7. The drying apparatus for lithium tetrafluoroborate according to claim 1, characterized in that, The vacuum rake dryer has a heating medium inlet on its side wall.

8. The drying apparatus for lithium tetrafluoroborate according to claim 1, characterized in that, The bottom of the neutralization reactor is equipped with a material outlet valve, which is connected to the material flow pipe.

9. The drying apparatus for lithium tetrafluoroborate according to claim 1, characterized in that, The centrifugal filter is equipped with a discharge valve at the bottom, and the discharge valve is connected to the discharge pipe.

10. The drying apparatus for lithium tetrafluoroborate according to claim 1, characterized in that, The filter element has a filtration accuracy of 0.3µm to 0.5µm.

Images