A lithium sulfate solution oil removal separator

Abstract

The utility model discloses a lithium sulfate solution oil removal separator, aims at solving the problem of low efficiency of existing lithium sulfate solution oil removal method, cannot continuously operate. The utility model main body is a separation tank body, and the inside of jar is provided with purification liquid layer, coalescence layer, inclined plate layer from bottom to top. The top center of tank body is equipped with an oil collection cavity, is used for collecting and temporarily storing the separated floating oil. The sidewall of oil collection cavity is equipped with visual oil window and liquid level sensor, and automatic oil drain valve is connected to oil drain. Oil-containing solution enters the inside of jar through import, first through coalescence layer and makes small oil drop coalescence and become big, and then utilizes inclined plate layer and accelerates oil drop to float to liquid surface. The purified liquid after separation is discharged from lower outlet, and the floating oil overflows to the top oil collection cavity and then concentrates and discharges. The utility model can realize the continuous efficient oil removal of lithium sulfate solution, and is especially suitable for lithium battery material preparation process.

Description

Technical Field

[0001] This utility model belongs to the field of hydrometallurgy and lithium-ion battery cathode material recycling, specifically involving a separation and purification device for efficiently removing organic oil from lithium sulfate solution produced by lithium iron phosphate or ternary material leaching process. Background Technology

[0002] In the production of lithium-ion battery cathode materials (such as ternary materials and lithium iron phosphate), high-purity lithium sulfate solutions are typically prepared using processes such as extraction and crystallization. During these upstream processes, trace amounts of organic phases (such as extractants, kerosene, etc.) or lubricating greases may be introduced, forming oil floats on the surface of the lithium sulfate solution. If these oily impurities are not removed, they will severely affect the subsequent precipitation process of lithium salts (such as lithium carbonate and lithium hydroxide), leading to problems such as decreased product purity, deteriorated crystal morphology, and difficulty in filtration.

[0003] Currently, common methods for removing floating oil from solution surfaces include oil skimmers, adsorption, or simple settling. Oil skimmers can only remove most of the surface oil and are not effective against dispersed, tiny oil droplets. Adsorption methods (such as using oleophilic filter cartridges) are effective, but the adsorption material needs to be replaced frequently, resulting in high operating costs and the risk of becoming a secondary source of pollution. Settling methods are too time-consuming and inefficient, failing to meet the needs of continuous industrial production.

[0004] Therefore, there is an urgent need to develop a dedicated separation device that can efficiently, continuously, and with low consumption remove floating oil from lithium sulfate solutions and facilitate oil phase recovery. Summary of the Invention

[0005] The purpose of this invention is to provide a lithium sulfate solution oil separator to solve the problems mentioned in the background art, such as low separation efficiency, inability to operate continuously and automatically, and high operation and maintenance costs of existing oil removal methods.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a lithium sulfate solution oil separator, comprising a separation tank; the separation tank is a closed structure, with a solution inlet at the top, a purified liquid outlet at the bottom, and a drain outlet at the bottom;

[0007] An oil collection chamber is provided at the center of the top of the tank to collect and temporarily store the separated floating oil; the lower part of the oil collection chamber is connected to the main cavity of the tank through a constricted neck; an oil discharge port is provided on the oil collection chamber;

[0008] The separation tank contains, from bottom to top, the following components:

[0009] The purification liquid layer is the purification liquid area after oil-water separation, and is used for the external discharge of the purification liquid.

[0010] The coalescing layer, including a filter membrane made of a hydrophobic and oleophilic coalescing material with high chemical stability and resistance to acid and alkali corrosion, is used to capture and coalesce the tiny oil droplets dispersed in the solution, causing them to merge into larger oil droplets that are easier to float.

[0011] The inclined plate layer, composed of multiple parallel inclined plates, is used to accelerate the upward separation of oil droplets.

[0012] The thickness of the purification liquid layer is 20%-25% of the height of the main cavity of the separation tank; the thickness of the coalescing layer is 25%-30% of the height of the main cavity of the separation tank; and the thickness of the inclined plate layer is 20%-30% of the height of the main cavity of the separation tank.

[0013] The hydrophobic and oleophilic coalescing material is polypropylene fiber, glass fiber, polytetrafluoroethylene, or a composite coalescing material.

[0014] The composite coalescing material may be the composite coalescing material for water degreasing provided by Chinese Patent CN106823470B.

[0015] The coalescing material can maintain its physical structure and surface properties for a long time under the working environment of lithium sulfate solution, and is not easily swollen, embrittled or degraded.

[0016] The bottom of the coalescing layer has a support mesh plate for supporting the filter membrane.

[0017] The inclined plate is fixed to the tank wall of the separation tank; the inclination angle of the inclined plate is 45°~60°.

[0018] The inclined plates are made of rigid, smooth, and corrosion-resistant materials, such as stainless steel (e.g., SS304 / 316L), engineering plastics (e.g., PVC, PP), or composite materials. The plate surface is smooth and has a low coefficient of friction, which not only facilitates the sliding of oil droplets but also prevents the adhesion of dirt and crystals, reduces maintenance requirements, and ensures long-term separation efficiency.

[0019] A visible oil window and a liquid level sensor are provided on the side wall of the oil collecting chamber.

[0020] The oil drain port is connected to an automatic oil drain valve, which is connected to the liquid level sensor to form an automatic oil drain system. When the oil level in the oil collection chamber reaches a set height, the system automatically opens the oil drain valve to drain the oil, achieving unattended operation.

[0021] The separation tank is also equipped with a level gauge for monitoring and controlling the liquid level inside the tank, which is used to monitor and control the liquid level in real time to ensure that the oil-water separation interface is stable in the optimal working area.

[0022] The solution inlet is a tangential inlet, which generates a gentle vortex when the liquid enters the separation tank, using centrifugal force to achieve primary oil-water separation and reduce the load on the subsequent coalescence unit.

[0023] The solution inlet is located above the upper edge of the coalescing layer and below the lower edge of the inclined plate layer.

[0024] The purified liquid outlet is located below the coalescing layer, at the bottom of the purified liquid layer, to ensure that the discharged solution is a pure solution that has been fully separated.

[0025] The separation tank is a vertical cylindrical structure or a horizontal tank structure.

[0026] The oil-containing solution enters through the inlet, first passing through a coalescence layer to agglomerate and enlarge the tiny oil droplets, and then using an inclined plate layer to accelerate the oil droplets to float to the liquid surface. The separated purified liquid is discharged from the lower outlet, while the floating oil overflows to the top oil collection chamber for centralized discharge. This invention integrates coalescence and inclined plate separation, significantly improving oil-water separation efficiency and automation, enabling continuous and efficient oil removal from lithium sulfate solutions, and is particularly suitable for lithium battery material preparation processes.

[0027] Compared with existing technologies, the advantages of this invention are: 1) High separation efficiency: This invention innovatively integrates three mechanisms—cyclone pre-separation, coalescence, and inclined plate separation—into one, forming a synergistic effect. It achieves extremely high removal rates for oil droplets of micron size and above, significantly improving the quality of lithium sulfate solutions. 2) Continuous automated operation: The device can achieve fully continuous automated operation of feeding, separation, liquid discharge, and oil discharge, perfectly adapting to modern industrial continuous production processes, resulting in high production efficiency. 3) Low operating and maintenance costs: The core separation elements (coalescing layer filter membrane, inclined plate layer inclined plates) do not require frequent replacement, maintenance is simple, energy consumption is low, and the overall operating cost is far lower than existing technologies such as adsorption methods. 4) Automation and visualization: Integrated automatic liquid level control and automatic oil discharge functions reduce the intensity and error of manual operation; the visible oil window facilitates on-site observation of the operating status. 5) Compact structure and wide adaptability: The device has a reasonable layout, small footprint, and is easy to install and modify in existing production lines. Besides lithium sulfate solutions, it is also suitable for other chemical processes requiring oil-water separation. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of this utility model.

[0029] The following are the labels in the diagram: 1. Separation tank; 2. Solution inlet; 3. Purified liquid outlet; 4. Drain outlet; 5. Oil collection chamber; 6. Neck; 7. Coalescing layer; 8. Inclined plate layer; 9. Visual oil window; 10. Liquid level sensor; 11. Oil drain outlet; 12. Automatic oil drain valve; 13. Liquid level gauge; 14. Purified liquid layer; 15. Support mesh plate. Detailed Implementation

[0030] The following is in conjunction with the appendix Figure 1 The present invention will be described in detail with reference to specific embodiments.

[0031] like Figure 1 As shown, the oil separator device of this utility model has a cylindrical vertical separation tank 1 as its main body. The separation tank 1 is provided with a solution inlet 2 at the top, a purified liquid outlet 3 at the bottom, and a drain outlet 4 at the bottom. An oil collecting chamber 5 is provided at the center of the top of the separation tank 1; the lower part of the oil collecting chamber 5 is connected to the main cavity of the tank through a neck 6; an oil drain outlet 11 is provided on the oil collecting chamber 5.

[0032] The separation tank 1 is arranged from bottom to top as follows: purification liquid layer 14, coalescence layer 7, inlet liquid layer, and inclined plate layer 8.

[0033] The purification liquid layer 14 is located at the bottom of the main cavity of the tank, and the thickness of the purification liquid layer 14 is 25% of the height of the main cavity of the separation tank 1.

[0034] The coalescing layer 7 is located above the purification liquid layer 14, and its thickness is 25% of the height of the main cavity of the separation tank 1. The coalescing layer 7 includes a filter membrane and a support mesh plate 15 for supporting the filter membrane.

[0035] The liquid inlet layer is located above the coalescing layer 7, and the thickness of the liquid inlet layer is 30% of the height of the main cavity of the separation tank 1.

[0036] The inclined plate layer 8 is located at the upper part of the main cavity of the tank, and the thickness of the inclined plate layer 8 is 20% of the height of the main cavity of the separation tank 1.

[0037] Solution inlet 2 is located at the top of the inlet layer. The position of solution inlet 2 is higher than the upper edge of the coalescing layer and lower than the lower edge of the inclined plate layer. Purified liquid outlet 3 is located below the coalescing layer, at the bottom of the purified liquid layer, to ensure that the discharged solution is a fully separated, pure solution.

[0038] The oil-containing lithium sulfate solution enters from the tangential solution inlet 2 located at the top of the separation tank 1, generating a gentle centrifugal force inside the tank to achieve preliminary separation.

[0039] The solution flows downwards, passing through the coalescing layer 7 located at the bottom of the tank. The coalescing layer 7 comprises a filter membrane made of a hydrophobic and oleophilic coalescing material with high chemical stability and resistance to acid and alkali corrosion, effectively capturing and coalescing micron-sized oil droplets. The larger oil droplets, after coalescing, move upwards under buoyancy.

[0040] Above the coalescing layer 7, an inclined plate layer 8 is provided, consisting of multiple parallel inclined plates. The inclination angle (angle with the horizontal plane) of the inclined plates is 60°. The function of the inclined plate layer is to significantly increase the effective separation area, greatly shortening the path and time for oil droplets to rise to the liquid surface according to the "shallow pool theory," thereby improving the overall separation efficiency. After the rising oil droplets impact the bottom surface of the inclined plates, they quickly slide up the plate surface to the liquid surface, greatly accelerating the separation process. The purified lithium sulfate solution is continuously discharged from the purified liquid outlet 3 located below the coalescing layer 7. A drain valve is provided at the purified liquid outlet 3.

[0041] The separated floating oil accumulates on the liquid surface and overflows through a constricted neck 6 to the top oil collection chamber 5. A visual oil window 9 and a level sensor 10 are installed on the side wall of the oil collection chamber 5. When the oil layer accumulates to a certain thickness, the level sensor 10 sends a signal to open the automatic oil drain valve 12 at the top, discharging the waste oil through the drain port 11. The drain port 4 at the bottom of the tank is used for periodic cleaning and removal of any small amounts of solid impurities that may accumulate. The level gauge 13 on the tank is used to monitor and maintain the stability of the total liquid level inside the tank.

[0042] The working principle of this invention is as follows: An oil-containing lithium sulfate solution enters the separation tank through a tangential solution inlet, where a swirling flow is generated for initial separation. The solution then flows downwards through a coalescing layer, where micron-sized oil droplets are efficiently coalesced into larger droplets. These larger droplets rise under buoyancy and are rapidly guided to the liquid surface as they pass through the inclined plate layer. The purified solution is then discharged from the purified liquid outlet. The floating oil accumulated on the liquid surface overflows through the neck to the top oil collection chamber. When the oil layer reaches a certain thickness, a level sensor triggers an automatic oil drain valve, discharging the waste oil. A drain outlet at the bottom of the tank is used for regular maintenance and cleaning.

[0043] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the protection scope of this utility model.

Claims

1. A lithium sulfate solution oil separator, characterized in that, It includes a separation tank (1); the separation tank (1) is provided with a solution inlet (2) at the top, a purified liquid outlet (3) at the bottom, and a drain outlet (4) at the bottom; The top of the separation tank (1) is provided with an oil collection chamber (5); the lower part of the oil collection chamber (5) is connected to the main cavity of the tank through a neck (6); an oil discharge port (11) is provided on the oil collection chamber (5). The separation tank (1) is equipped with the following components from bottom to top: The purification liquid layer (14) is the purification liquid zone after oil-water separation, used for the external discharge of purification liquid; The coalescing layer (7) includes a filter membrane made of a hydrophobic and oleophilic coalescing material for coalescing tiny oil droplets in the solution; The inclined plate layer (8) consists of multiple parallel inclined plates, which are used to accelerate the separation of oil droplets.

2. The lithium sulfate solution oil separator according to claim 1, characterized in that: The thickness of the purification liquid layer (14) is 20%-25% of the height of the main cavity of the separation tank (1); the thickness of the coalescing layer (7) is 25%-30% of the height of the main cavity of the separation tank (1); and the thickness of the inclined plate layer (8) is 20%-30% of the height of the main cavity of the separation tank (1).

3. The lithium sulfate solution oil separator according to claim 1, characterized in that: The hydrophobic and oleophilic coalescing material is polypropylene fiber, glass fiber, polytetrafluoroethylene, or a composite coalescing material.

4. The lithium sulfate solution oil separator according to claim 1, characterized in that: The bottom of the coalescing layer (7) has a support mesh plate (15) for supporting the filter membrane.

5. The lithium sulfate solution oil separator according to claim 1, characterized in that: The inclined plate is fixed on the tank wall of the separation tank (1); the inclination angle of the inclined plate is 45°~60°.

6. The lithium sulfate solution oil separator according to claim 1, characterized in that: The oil collecting chamber (5) is provided with a visible oil window (9) and a liquid level sensor (10) on its side wall.

7. The lithium sulfate solution oil separator according to claim 6, characterized in that: The oil drain port (11) is connected to an automatic oil drain valve (12), and the automatic oil drain valve (12) is connected to the liquid level sensor (10).

8. The lithium sulfate solution oil separator according to claim 1, characterized in that: The separation tank (1) is also equipped with a level gauge (13) for monitoring and controlling the liquid level inside the tank.

9. The lithium sulfate solution oil separator according to claim 1, characterized in that: The solution inlet (2) is a tangential inlet, which causes the liquid to swirl when it enters the separation tank (1); the position of the solution inlet (2) is higher than the upper edge of the coalescing layer (7) and lower than the lower edge of the inclined plate layer (8); the purified liquid outlet (3) is located at the lower part of the purified liquid layer (14).

10. A lithium sulfate solution oil separator according to claim 1, characterized in that: The separation tank (1) is a vertical cylindrical structure or a horizontal tank structure.

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