Lithium hexafluorophosphate synthetic liquid filter

Abstract

The utility model relates to the technical field of lithium hexafluorophosphate production equipment, and particularly discloses a lithium hexafluorophosphate synthetic liquid filter. The device structurally comprises a tank body, the tank body sequentially comprises an upper cover, a filtering tank and an outlet tank from top to bottom, a feeding pipe is arranged on the filtering tank, a discharging pipe is arranged on the outlet tank, and an upper fixing plate for dividing the filtering tank and the upper cover into two cavities is arranged at the end, close to the upper cover, of the filtering tank; a lower fixing plate for dividing the filtering tank and the outlet tank into two cavities is arranged at one end, close to the outlet tank, of the filtering tank, a plurality of cylindrical filter elements are arranged between the upper fixing plate and the lower fixing plate, and filter element openings for communicating the interiors of the cylindrical filter elements with the outlet tank are formed in the lower ends of the cylindrical filter elements; the technical problems that no independent lithium hexafluorophosphate synthetic liquid filtering equipment exists in the prior art, the filtering area of an existing filtering plate is small, filtering is not thorough, and the requirement for large-yield production cannot be met are solved through the multiple cylindrical filter elements.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium hexafluorophosphate production equipment, in particular to a lithium hexafluorophosphate synthetic liquid filter. Background Art

[0002] Lithium hexafluorophosphate, as a key material for the preparation of lithium-ion battery electrolytes, has been favored by the market due to the development of new energy vehicles in recent years, and the market demand is growing.

[0003] Currently, the industrial production methods for lithium hexafluorophosphate (LFP) are mainly divided into the gas-solid reaction method, the hydrogen fluoride solvent method, and the organic solvent method. The hydrogen fluoride solvent method is the most widely used method for preparing LFP. The process involves adding phosphorus pentafluoride, lithium fluoride, and other materials to hydrogen fluoride to form a solution. After reaction in the solution, a synthetic solution containing LFP as the main component is obtained. The synthetic solution is then subjected to low-temperature crystallization, solidification separation, drying, pulverization, and packaging to obtain the LFP product. However, due to the introduction of insoluble impurities during the initial production process, direct low-temperature crystallization of the synthetic solution will cause these impurities to become crystal nuclei. The lithium hexafluorophosphate precipitated in the synthetic solution will then encapsulate these impurities, reducing the purity of the LFP. To remove these insoluble impurities, the synthetic solution must be purified. In the prior art, a filter plate is provided before crystallization to filter impurities, and crystallization is directly performed after filtration using the filter plate. For example, patent application number CN202221973862.9 discloses a continuous solid-liquid separator for preparing lithium hexafluorophosphate, which simply filters impurities and directly crystallizes after filtration. This filtration method is too simple, resulting in incomplete filtration and a small filtration area. Moreover, if the impurity filter plate is clogged, the entire crystallization device must be stopped, which is not convenient for large-scale production. Existing filtration equipment in the chemical industry includes plate and frame filtration, filter bags, and other filtration equipment. However, lithium hexafluorophosphate synthesis liquid contains volatile harmful gases such as hydrofluoric acid, which are harmful to the human body when inhaled. Therefore, a closed space is required, and plate and frame filtration equipment and filter bags cannot meet this requirement. Simple filter plates cannot complete continuous and large-volume filtration and cannot meet large-scale production requirements.

[0004] Therefore, it is necessary to design a filtering device for lithium hexafluorophosphate synthetic solution to filter the lithium hexafluorophosphate synthetic solution during large-scale production. Utility Model Content

[0005] The purpose of the utility model is to provide a lithium hexafluorophosphate synthetic liquid filter to solve the technical problems that there is no separate lithium hexafluorophosphate synthetic liquid filtering equipment in the prior art, the existing filter plate has a small filtering area, the filtering is not clean, and it cannot meet the requirements of large-scale production.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is as follows: a lithium hexafluorophosphate synthetic liquid filter includes a tank body, which includes an upper cover, a filter tank and an outlet tank from top to bottom. The end of the filter tank close to the upper cover is provided with an upper fixed plate that divides the filter tank and the upper cover into two cavities, and the end of the filter tank close to the outlet tank is provided with a lower fixed plate that divides the filter tank and the outlet tank into two cavities. Several cylindrical filter elements are provided between the upper fixed plate and the lower fixed plate, and the lower end of the cylindrical filter element is provided with a filter element opening that connects the interior of the cylindrical filter element with the outlet tank.

[0007] The beneficial effects of this embodiment are:

[0008] 1. In the prior art, the filtration of lithium hexafluorophosphate synthesis liquid is mostly performed by using a simple filter plate in a crystallization device and then directly crystallizing it. However, as the output increases, this simple filter plate becomes clogged, causing the entire crystallization device to shut down, disrupting its production continuity. Therefore, it is necessary to design a separate filtration device to complete the filtration process of the lithium hexafluorophosphate synthesis liquid. However, most filtration devices are plate-and-frame filtration for intermittent production, or the filter bags are mostly open filtration devices. However, the production volume of lithium hexafluorophosphate synthesis liquid is large, and the solution contains harmful volatile gases such as hydrofluoric acid, making this type of filtration device unsuitable. The tank body is designed in this application to ensure its sealing, so that harmful gases such as hydrofluoric acid in the synthetic liquid cannot evaporate, and the tank body is divided into three parts. A cylindrical filter element is set in the middle filter tank. After the synthetic liquid enters the filter tank, it passes through the cylindrical filter element for filtration and flows from the cylindrical filter element to the outlet tank. The filtered synthetic liquid can be discharged quickly, and the filtration efficiency is high. In addition, multiple cylindrical filter elements can be set in the filter tank to increase its filtration area and further improve the filtration efficiency, which meets the requirements for filtration of lithium hexafluorophosphate synthetic liquid.

[0009] Furthermore, the cylindrical filter element is provided with fixing rings on the upper and lower sides to enhance the rigidity of the cylindrical filter element.

[0010] Furthermore, the fixing ring is provided with a threaded head, and both the upper fixing plate and the lower fixing plate are provided with fixing holes for fixing the cylindrical filter element, and the fixing holes are threaded holes that match the threaded head.

[0011] Furthermore, an exhaust pipe is provided on the upper cover.

[0012] Furthermore, a sewage pipe is provided at the lower end of the filter tank.

[0013] Furthermore, the filter tank is provided with a connecting plate with through holes, the upper cover is provided with a mounting plate with through holes, and the filter tank and the upper cover are fixed with bolts using the through holes on the connecting plate and the mounting plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of an embodiment of the utility model.

[0015] Figure 2 This is a schematic diagram of the structure of the filter element according to an embodiment of the utility model.

[0016] Figure 3 This is a schematic diagram of the fixing ring structure of an embodiment of the utility model.

[0017] Figure 4 It is a cross-sectional view of an embodiment of the present utility model. DETAILED DESCRIPTION

[0018] The following is further described in detail through specific implementation methods:

[0019] The figure marks in the drawings of the specification include: filter tank 1, connecting plate 11, feed pipe 12, drain pipe 13, upper cover 2, mounting plate 21, exhaust pipe 22, spare pipe 23, outlet tank 3, discharge pipe 31, filter element 4, upper fixing plate 41, lower fixing plate 42, cylindrical filter element 43, fixing ring 431, and threaded head 432.

[0020] Implementation example Figures 1 to 4 The figure shows a lithium hexafluorophosphate synthetic liquid filter comprising a tank body, which comprises, from top to bottom, an upper cover 2, a filter tank 1, and an outlet tank 3. The upper cover is a semi-sealed shell formed by welding a cylindrical structure to a hemispherical structure. An exhaust pipe 22 is welded to the upper cover 2 and communicates with the inner cavity of the upper cover. Therefore, the air inside the tank can be evacuated using the exhaust pipe 22 before opening the tank body. A backup pipe 23 is also provided on the upper cover 2, which can be used directly to evacuate the air if the exhaust pipe 22 is damaged. A mounting plate 21 is also welded to the circumference of the upper cover 2, with a through hole formed in the mounting plate 21.

[0021] A filter tank 1 is provided below the upper cover 2. The filter tank 1 is a cylindrical barrel structure. A connecting plate 11 is welded to the upper end of the outer periphery of the filter tank 1. The connecting plate 11 also has through holes. Therefore, the mounting plate 21 of the upper cover 2 can be aligned with the connecting plate 11 and bolted together to form a whole. The upper cover 2 and the filter tank 1 are installed as a whole. A feed pipe 12 is provided at the upper end of the filter tank 1 and below the connecting plate 11. The feed pipe 12 is connected to the inner cavity of the filter tank 11. Therefore, the lithium hexafluorophosphate synthetic liquid can be passed into the inner cavity of the filter tank 1. A drain pipe 13 is provided at the lower end of the filter tank 1. The drain pipe 13 is also connected to the inner cavity of the filter tank 1. Therefore, the filtered insoluble impurities in the filter tank 1 can be discharged to ensure continuous filtration.

[0022] At the lower end of the filter tank 1 is an outlet tank 3. This integral part of the filter tank 1 bears a similar structure to the upper cover 2, consisting of a semi-enclosed shell connected to a cylindrical section and a hemisphere. However, a discharge pipe 31 is located at the center of the lowermost end of the spherical shell of the outlet tank 3. This pipe connects to the internal cavity of the outlet tank 3, allowing the filtered lithium hexafluorophosphate to be discharged through the discharge pipe 31.

[0023] A filter element 4 is provided within the filter tank 1. The filter element 4 comprises an upper fixing plate 41, a lower fixing plate 42, and a cylindrical filter element 43. The lower fixing plate 42 is welded to the inner wall of the filter tank 1, dividing the filter tank 1 and the outlet tank into two closed cavities. Therefore, the lithium hexafluorophosphate synthetic liquid entering the filter tank 1 from the feed pipe 12 cannot pass through the lower fixing plate 42 and enter the outlet tank 3. The upper fixing plate 41 is fixed to the interior of the filter tank 1 with bolts. A ring-shaped protrusion is provided on the inner wall of the filter tank 1. The protrusion reduces the inner diameter of the filter tank 1. The diameter of the upper fixing plate 41 is larger than the reduced inner diameter, so the upper fixing plate 41 can rest on the ring-shaped protrusion. Seven cylindrical filter elements 43 are provided between the upper fixing plate 41 and the lower fixing plate 42. Therefore, both the upper fixing plate 41 and the lower fixing plate 42 are provided with fixing holes for the cylindrical filter elements, and the fixing holes are threaded holes. A fixing ring 431 is provided at both the upper and lower ends of the cylindrical filter element 43. The fixing ring 431 can improve the rigidity of the cylindrical filter element. Between the upper and lower fixing rings 431 is a cylindrical shell made of curled sheet metal. A plurality of filter holes are provided on the cylindrical shell. A threaded head 432 is welded to the lower end of the fixing ring 431, but the threaded head 432 at the end connected to the upper fixing plate 41 is solid, which can close the upper end of the cylindrical filter element 43, and a filter element opening is provided in the middle of the threaded head 432 connected to the lower fixing plate 42. The filter element opening is connected to the inner cavity of the cylindrical filter element 43, so that the lithium hexafluorophosphate synthetic liquid can pass through the filter holes on the cylindrical filter element 43 to reach the inner cavity of the cylindrical filter element, and then enter the outlet tank 3 through the filter element opening.

[0024] When installing the cylindrical filter element 43, first tighten the threaded head 432 at the lower end of the cylindrical filter element 43 with the fixing hole on the lower fixing plate 42, and put a fluororubber gasket on the threaded head for sealing. When the cylindrical filter element 43 is connected to the lower fixing plate 42, align the upper fixing plate 41 with the threaded head 432 at the upper end of the cylindrical filter element 43, pass the upper fixing plate 41 through the threaded head 432 at the upper end of the cylindrical filter element and place it on the annular protrusion, then use a nut to tighten the threaded head 432 at the upper end of the cylindrical filter element 43, press the upper fixing plate 41 onto the annular protrusion, and fluororubber gaskets are also needed to be sealed between the upper fixing plate 41 and the annular protrusion, and between the upper fixing plate 41 and the threaded head 432 at the upper end of the cylindrical filter element 43.

[0025] The above is only an embodiment of the present invention, and the commonly known specific structures and characteristics of the scheme are not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, and these should also be regarded as the scope of protection of the present invention. These will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection claimed by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A lithium hexafluorophosphate synthetic liquid filter, comprising a tank body, characterized in that: The tank body includes an upper cover, a filter tank and an outlet tank from top to bottom. The filter tank is provided with a feed pipe, and the outlet tank is provided with a discharge pipe. An upper fixing plate is provided at one end of the filter tank close to the upper cover, which divides the filter tank and the upper cover into two cavities. An lower fixing plate is provided at one end of the filter tank close to the outlet tank, which divides the filter tank and the outlet tank into two cavities. Several cylindrical filter elements are provided between the upper fixing plate and the lower fixing plate. The lower end of the cylindrical filter element is provided with a filter element opening that connects the interior of the cylindrical filter element with the outlet tank.

2. The lithium hexafluorophosphate synthetic liquid filter according to claim 1, characterized in that: The cylindrical filter element is provided with fixing rings on the upper and lower sides for reinforcing the rigidity of the cylindrical filter element.

3. The lithium hexafluorophosphate synthetic liquid filter according to claim 2, characterized in that: The fixing ring is provided with a threaded head, and both the upper fixing plate and the lower fixing plate are provided with fixing holes for fixing the cylindrical filter element, and the fixing holes are threaded holes that match the threaded head.

4. The lithium hexafluorophosphate synthetic liquid filter according to claim 1, characterized in that: An exhaust pipe is provided on the upper cover.

5. The lithium hexafluorophosphate synthetic liquid filter according to claim 1, characterized in that: A sewage pipe is provided at the lower end of the filter tank.

6. The lithium hexafluorophosphate synthetic liquid filter according to claim 1, characterized in that: The filter tank is provided with a connecting plate with a through hole, the upper cover is provided with a mounting plate with a through hole, and the filter tank and the upper cover are fixed with bolts using the through holes on the connecting plate and the mounting plate.

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