Solute separation device for recovering lithium hydroxide and sodium sulfate

Abstract

The utility model discloses a solute separation device for recycling lithium hydroxide and sodium sulfate. Comprising a chilled water tank for carrying out freezing treatment on feed liquid, an evaporator for carrying out evaporation treatment on the feed liquid treated by the chilled water tank, a condenser for treating steam generated after treatment by the evaporator, and a filtering container for filtering concentrated liquid treated by the evaporator, the evaporator comprises an evaporator cavity and an evaporator heat exchange pipe, and a steam delivery pipe is arranged on the evaporator cavity; the condenser comprises a condenser cavity and a condenser heat exchange pipe; the condenser cavity is communicated with the steam delivery pipe; the chilled water tank comprises a tank body and a water tank heat exchange pipe; the inlet end of the evaporator heat exchange pipe is respectively communicated with the outlet ends of the water tank heat exchange pipe and the condenser heat exchange pipe; the outlet end of the evaporator heat exchange pipe is respectively communicated with the inlet ends of the water tank heat exchange pipe and the condenser heat exchange pipe; therefore, the separation efficiency is improved, and the separation purity can also be improved.

Description

Technical Field

[0001] This utility model relates to a solute separation device, and more particularly to a solute separation device suitable for ultra-small separation operations of mixed solutions containing lithium hydroxide and sodium sulfate. Background Technology

[0002] In a mixed solution containing lithium hydroxide and sodium sulfate, MVR (forced recirculation evaporation) and MED (multi-effect evaporation) systems are commonly used as evaporation separation processes to achieve their separation.

[0003] Although MVR (forced circulation evaporation) and MED (multi-effect evaporation) evaporation systems can separate mixed solutions containing lithium hydroxide and sodium sulfate, they suffer from relatively low separation purity, mediocre separation effect, and high operating costs, especially in experiments with small amounts of mixed solution.

[0004] Therefore, there is an urgent need for a solute separation device for recovering lithium hydroxide and sodium sulfate that can improve separation efficiency and achieve high separation purity, in order to overcome one or more of the above-mentioned defects. Utility Model Content

[0005] The purpose of this invention is to provide a solute separation device for recovering lithium hydroxide and sodium sulfate with improved separation efficiency and high separation purity.

[0006] To achieve the above objectives, the solute separation device for recovering lithium hydroxide and sodium sulfate of this utility model includes a chilled water tank for freezing the feed solution, an evaporator for evaporating the feed solution after treatment in the chilled water tank, a condenser for treating the steam generated after treatment in the evaporator, and a filter container for filtering the concentrated liquid after treatment in the evaporator. The evaporator includes an evaporator cavity and evaporator heat exchange tubes located within the evaporator cavity, and a steam delivery pipe communicating with the evaporator cavity is provided on the evaporator cavity. The condenser includes a condenser cavity and condenser heat exchange tubes located within the condenser cavity, and the condenser cavity is connected to the steam delivery pipe. The chilled water tank includes a tank body and a water tank heat exchange tube located within the tank body. The inlet end of the evaporator heat exchange tube is connected to the outlet ends of both the water tank heat exchange tube and the condenser heat exchange tube, respectively, and the outlet end of the evaporator heat exchange tube is connected to the inlet ends of both the water tank heat exchange tube and the condenser heat exchange tube, respectively.

[0007] Compared with existing technologies, by using a combination of a chilled water tank, evaporator, condenser and filter container, the solute separation device of this invention uses a combination of freezing and evaporation to process the liquid, thus improving the separation efficiency and high separation purity of the liquid, and reducing the process operating cost.

[0008] Preferably, the solute separation device of this utility model further includes an outlet pipe and an inlet pipe. The outlet end of the evaporator heat exchange tube is connected to the inlet ends of both the water tank heat exchange tube and the condenser heat exchange tube through the outlet pipe. The inlet end of the evaporator heat exchange tube is connected to the outlet ends of both the water tank heat exchange tube and the condenser heat exchange tube through the inlet pipe.

[0009] Preferably, there are multiple chilled water tanks that are spaced apart from each other, and the inlet end of the heat exchange pipe of each chilled water tank is connected to the outlet pipe, and the outlet end of the heat exchange pipe of each chilled water tank is connected to the inlet pipe.

[0010] Preferably, the solute separation device of this utility model further includes a cooling fan and an expansion valve mounted on the outlet pipe. The inlet pipe is provided with a first branch pipe at an external position near the evaporator, and the outlet pipe is provided with a second branch pipe at an external position near the condenser. The cooling fan is arranged opposite to the first branch pipe and the second branch pipe respectively.

[0011] Preferably, the solute separation device of this utility model further includes a gas-liquid separator, a compressor, and an oil separator, which are sequentially assembled on the outlet pipe along the medium flow direction within the outlet pipe.

[0012] Preferably, the evaporator cavity is further provided with a liquid delivery pipe communicating with the evaporator cavity, and the filter container is communicating with the liquid delivery pipe.

[0013] Preferably, the steam delivery pipe is located at the top of the evaporator cavity, and the liquid delivery pipe is located at the bottom of the evaporator cavity.

[0014] Preferably, the solute separation device of this invention further includes a vacuum system connected to the condenser cavity.

[0015] Preferably, the evaporator heat exchange tube, condenser heat exchange tube, water tank heat exchange tube, outlet pipe and inlet pipe together form a loop for the refrigerant to circulate and be transported, and the refrigerant circulates and is transported in this loop.

[0016] Preferably, the refrigerant in the evaporator heat exchange tube is in a high-temperature gaseous state, the refrigerant in the water tank heat exchange tube is in a low-temperature liquid state, and the refrigerant in the condenser heat exchange tube is in a low-temperature liquid state. Attached Figure Description

[0017] Figure 1 This is a plan view of the solute separation device of this utility model.

[0018] Figure 2 yes Figure 1A plan view of the chilled water tank in the solute separation device shown.

[0019] Figure 3 yes Figure 1 A plan view of the evaporator in the solute separation device shown.

[0020] Figure 4 yes Figure 1 A plan view of the condenser in the solute separation device shown. Detailed Implementation

[0021] To explain the technical content and structural features of this utility model in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0022] Please combine Figure 1 The solute separation device 100 of this invention is suitable for separating mixed solutions containing lithium hydroxide and sodium sulfate to achieve the recovery of lithium hydroxide and sodium sulfate. The solute separation device 100 includes a chilled water tank 10 for freezing the feed solution, an evaporator 20 for evaporating the feed solution after processing in the chilled water tank 10, a condenser 30 for processing the steam generated after processing in the evaporator 20, and a filter container 40 for filtering the concentrated liquid after processing in the evaporator 20.

[0023] Combined Figure 2 The chilled water tank 10 includes a tank body 11 and a water tank heat exchange pipe 12 disposed on the tank body 11. Optionally, in Figure 1 and Figure 2 In this example, the water tank heat exchange tube 12 is arranged in an "S" shape to effectively increase the heat exchange area between the water tank heat exchange tube 12 and the liquid entering the tank 11, thereby improving the heat exchange effect between the refrigerant in the water tank heat exchange tube 12 and the liquid entering the tank 11. Obviously, depending on actual needs, the water tank heat exchange tube 12 can also be arranged in other shapes, so it is not limited to this. Figure 1 and Figure 2 The above is the limit.

[0024] And combined Figure 4 The condenser 30 includes a condenser cavity 31 and a condenser heat exchange tube 32 disposed in the condenser cavity 31. Optionally, it is located in... Figure 1 and Figure 4In this example, the condenser heat exchange tube 32 is arranged in an "S" shape to effectively increase the heat exchange area between the condenser heat exchange tube 32 and the steam entering the condenser cavity 31, thereby improving the heat exchange effect between the refrigerant in the condenser heat exchange tube 32 and the steam entering the condenser cavity 31. Obviously, the condenser heat exchange tube 32 can also be arranged in other shapes according to actual needs. In addition, the condenser cavity 31 is connected to the steam delivery pipe 23 to meet the requirement that the steam generated by the liquid during the evaporation process of the evaporator 20 enters the condenser cavity 31 along the steam delivery pipe 23, and then the condenser 30 condenses the steam.

[0025] And combined Figure 3 The evaporator 20 includes an evaporator cavity 21 and an evaporator heat exchange tube 22 disposed in the evaporator cavity 21. Optionally, as an example, the evaporator heat exchange tube 22 is arranged in an "S"-shaped coil to effectively increase the heat exchange area between the evaporator heat exchange tube 22 and the liquid contained in the evaporator cavity 21, thereby improving the heat exchange effect between the refrigerant in the evaporator heat exchange tube 22 and the liquid contained in the evaporator cavity 21. Obviously, depending on actual needs, the evaporator heat exchange tube 22 can also be coiled in other shapes. Furthermore, the evaporator cavity 21 is provided with a steam delivery pipe 23 and a liquid delivery pipe 24 communicating with the evaporator cavity 21. The filter container 40 is connected to the liquid delivery pipe 24. Optionally, in... Figure 1 In this example, the steam delivery pipe 23 is located at the top of the evaporator cavity 21, which facilitates the delivery of steam generated in the evaporator cavity 21 to the condenser 30. The liquid delivery pipe 24 is located at the bottom of the evaporator cavity 21, which facilitates the gravity flow of the concentrated salt solution after evaporation and separation to the filter container 40 for filtration and separation. Obviously, depending on actual needs, the steam delivery pipe 23 and the liquid delivery pipe 24 can also be arranged in other suitable positions in the evaporator cavity 21. The liquid delivery pipe 24 can also be replaced by placing the filter container 40 below the liquid outlet of the evaporator cavity 21. Figure 1 As shown, the inlet end 221 of the evaporator heat exchange tube 22 is connected to the outlet end 122 of the water tank heat exchange tube 12 and the outlet end 322 of the condenser heat exchange tube 32, respectively. The outlet end 222 of the evaporator heat exchange tube 22 is connected to the inlet end 121 of the water tank heat exchange tube 12 and the inlet end 321 of the condenser heat exchange tube 32, respectively, to achieve the purpose of circulating refrigerant among the evaporator heat exchange tube 22, the water tank heat exchange tube 12, and the condenser heat exchange tube 32. More specifically, as follows:

[0026] like Figure 1As shown, as an example, the solute separation device 100 of this utility model also includes an outlet pipe 50 and an inlet pipe 60. In this case, the outlet end 222 of the evaporator heat exchange tube 22 is connected to the inlet end 121 of the water tank heat exchange tube 12 and the inlet end 321 of the condenser heat exchange tube 32 through the outlet pipe 50. The inlet end 221 of the evaporator heat exchange tube 22 is connected to the outlet end 122 of the water tank heat exchange tube 12 and the outlet end 322 of the condenser heat exchange tube 32 through the inlet pipe 60, so as to realize that the evaporator heat exchange tube 22, the condenser heat exchange tube 32, the water tank heat exchange tube 11, the outlet pipe 50 and the inlet pipe 60 together form a loop for refrigerant circulation, so as to achieve the purpose of refrigerant circulation in the loop. In the evaporator 20, the refrigerant in the evaporator heat exchange tube 22 is in a high-temperature gaseous state to meet the heat requirements of the evaporator 20 for evaporating the liquid treated by the chilled water tank 10; in the chilled water tank 10, the refrigerant in the tank heat exchange tube 12 is in a low-temperature liquid state to meet the requirement that the refrigerant in the tank heat exchange tube 12 absorbs a large amount of heat from the liquid in the tank 11, causing the refrigerant to change from a low-temperature liquid state to a high-temperature gaseous state, and raising the temperature of the liquid to the salt precipitation temperature to precipitate salt solids; in the condenser 30, the refrigerant in the condenser heat exchange tube 32 is in a low-temperature liquid state to meet the requirement that the refrigerant in the condenser heat exchange tube 32 absorbs a large amount of heat from the steam in the condenser cavity 31.

[0027] Additionally, in order to exchange heat between the excess high-temperature gaseous refrigerant and the air, a small portion of the low-temperature liquid refrigerant will also exchange heat with the air, and the refrigerant will be converted from a high-temperature gaseous state to a low-temperature liquid state. Figure 1 As an example, the solute separation device 100 of this invention also includes a cooling fan 70 and an expansion valve 80 mounted on the outlet pipe 50. The inlet pipe 60 has a first branch pipe 61 located near the exterior of the evaporator 20, and the outlet pipe 50 has a second branch pipe 51 located near the exterior of the condenser 30. The cooling fan 70 is arranged opposite to the first branch pipe 61 and the second branch pipe 51, respectively. Therefore, excess high-temperature gaseous refrigerant can exchange heat with the air via the cooling fan 70 through the first branch pipe 61, while a small portion of low-temperature liquid refrigerant can exchange heat with the air via the cooling fan 70 through the second branch pipe 51. Furthermore, to control the boiling temperature, the solute separation device 100 of this invention also includes a vacuum system 91 connected to the condenser cavity 31, to meet the requirement that steam entering the condenser cavity 31 via the steam delivery pipe 23 re-enter the vacuum system 91. Thus, the vacuum system 91 controls the main pressure by controlling the vacuum level within the control system, thereby controlling the boiling temperature.

[0028] like Figure 1As shown in the example, there are two chilled water tanks 10 separated from each other. The inlet end 121 of the heat exchange pipe 12 of each chilled water tank 10 is connected to the outlet pipe 50, and the outlet end 122 of the heat exchange pipe 12 of each chilled water tank 10 is connected to the inlet pipe 60. This design can realize the staged recovery of lithium hydroxide and sodium sulfate, that is, after the feed liquid is frozen by one chilled water tank 10, the feed liquid treated by the other chilled water tank 10 is treated, thus realizing continuous freezing crystallization. Obviously, depending on the actual needs, the number of chilled water tanks 10 can also be three or four, so it is not limited to one. Figure 1 As shown, when there are two chilled water tanks 10, there are two expansion valves 80. That is to say, the number of chilled water tanks 10 and expansion valves 80 is the same, so that one expansion valve 80 corresponds to one chilled water tank 10.

[0029] For example Figure 1 As shown, the solute separation device 100 of this utility model also includes a gas-liquid separator 92, a compressor 93 and an oil separator 94, which are sequentially assembled on the inlet pipe 60 along the flow direction of the medium (i.e., refrigerant) in the inlet pipe 60. Optionally, the compressor 93 is a turbo compressor, which provides power for the circulation of the refrigerant.

[0030] The working principle of the solute separation device of this utility model will be explained with reference to the accompanying drawings:

[0031] Add the feed solution (a mixed solution containing lithium hydroxide and sodium sulfate) to Figure 1 In the left chilled water tank 10, heat is exchanged with the low-temperature liquid refrigerant in the heat exchange tube 12 of the water tank. As the refrigerant absorbs the heat in the liquid, it changes from a low-temperature liquid to a high-temperature gas, and raises the temperature of the liquid to the salt precipitation temperature, precipitating salt solids.

[0032] through Figure 1 The filtered clear liquid from the treated saline solution in the left-hand chilled water tank 10 then enters... Figure 1 In the right-hand chilled water tank 10, heat is exchanged with the low-temperature liquid refrigerant in the heat exchange tube 12 of the water tank. The refrigerant absorbs a large amount of heat from the filtered clear liquid, causing the refrigerant to change from a low-temperature liquid state to a high-temperature gas state, and raising the temperature of the filtered clear liquid to the salt precipitation temperature, so that salt solids are precipitated.

[0033] go through Figure 1The filtered clear liquid from the salt-containing liquid processed by the right-side chilled water tank 10 enters the evaporator cavity 21 of the evaporator 20, where it exchanges heat with the high-temperature gaseous refrigerant in the evaporator heat exchange tube 22. The filtered clear liquid absorbs a large amount of heat from the refrigerant, causing the refrigerant to change from a high-temperature gaseous state to a low-temperature liquid state, and raising the temperature of the filtered clear liquid to the salt precipitation temperature. At the same time, steam (secondary steam) is generated, and the filtered clear liquid is also concentrated. In this process, the concentrated salt solution flows by gravity along the liquid delivery pipe 24 into the filter container 40 for filtration and separation, separating out salt crystals. The excess high-temperature gaseous refrigerant exchanges heat with the air through the cooling fan 70. The steam (secondary steam) undergoes gas-liquid separation through the high-efficiency demisting system and then enters the condenser cavity 31 of the condenser 30 through the steam delivery pipe 23, where it exchanges heat with the low-temperature liquid refrigerant in the condenser heat exchange pipe 32. The refrigerant absorbs a large amount of heat from the steam in the condenser cavity 31, causing the refrigerant to change from a low-temperature liquid state to a high-temperature gaseous state. A small portion of the low-temperature liquid refrigerant exchanges heat with the air through the cooling fan 70, thus completing one cycle of the liquid treatment.

[0034] Compared with the prior art, by using the combination of chilled water tank 10, evaporator 20, condenser 30 and filter container 40, the solute separation device 100 of this utility model adopts a combination of freezing and evaporation to process the liquid, thereby improving the separation efficiency and high separation purity of the liquid, and reducing the process operating cost.

[0035] It should be further explained that lithium hydroxide can be separated by evaporation at 40℃ in evaporator 20, reducing the corrosion of evaporator 20 by alkaline solution at high temperatures. Additionally, when there are two chilled water tanks 10, a two-stage refrigeration system can be established to achieve continuous freeze-crystallization. In this two-stage refrigeration system, the first-stage freeze-crystallization temperature is 10℃, precipitating sodium sulfate decahydrate crystals. The liquid after filtration and separation enters the second-stage freeze-crystallization stage, where it continues to cool and crystallize, further reducing the sodium sulfate content in the solution. The second-stage freeze-crystallization temperature is -10℃, precipitating sodium sulfate decahydrate crystals. If the crystalline salt contains impurities, it returns to the first-stage refrigeration system. The liquid after the second-stage refrigeration system enters evaporator 20 for evaporation, concentration, and crystallization at 40℃ to precipitate lithium hydroxide. The concentrated liquid from evaporator 20 flows to filter container 40, where the filtered liquid is discharged. Since sodium sulfate decahydrate precipitates entirely in the first-stage freeze-crystallization stage, the higher temperature and lower viscosity of the liquid result in a lower lithium ion concentration compared to the second stage, leading to less crystal adsorption and a lower lithium ion loss rate.

[0036] It is worth noting that, Figure 1 In the middle, it can be manually or automatically moved to Figure 1 The left-hand chilled water tank 10 is filled with liquid, and then... Figure 1The treated liquid from the chilled water tank 10 on the left can enter through the external central pipe. Figure 1 The chilled water is added to the right-hand side of the tank 10, either manually or automatically. Figure 1 Inside the chilled water tank 10 on the right side; and Figure 1 The liquid material processed by the chilled water tank 10 on the right can enter the evaporator cavity 21 of the evaporator 20 through the external connecting pipe, or be added to the evaporator cavity 21 of the evaporator 20 manually or automatically.

[0037] The above-disclosed examples are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall fall within the scope of the present utility model.

Claims

1. A solute separation device for recovering lithium hydroxide and sodium sulfate, characterized in that, The system comprises a freezing water tank for freezing treatment of the feed liquid, an evaporator for evaporation treatment of the feed liquid treated by the freezing water tank, a condenser for treatment of steam generated by the evaporator, and a filter container for filtering of concentrated liquid treated by the evaporator; the evaporator comprises an evaporator cavity and an evaporator heat exchange pipe arranged at the evaporator cavity, and a steam delivery pipe arranged at the evaporator cavity and communicating with the evaporator cavity; the condenser comprises a condenser cavity and a condenser heat exchange pipe arranged at the condenser cavity, and the condenser cavity communicates with the steam delivery pipe; the freezing water tank comprises a tank body and a water tank heat exchange pipe arranged at the tank body; the inlet end of the evaporator heat exchange pipe communicates with the outlet end of both the water tank heat exchange pipe and the condenser heat exchange pipe, and the outlet end of the evaporator heat exchange pipe communicates with the inlet end of both the water tank heat exchange pipe and the condenser heat exchange pipe.

2. The solute separation device of claim 1, wherein, The system further comprises outlet and inlet pipelines, the outlet end of the evaporator heat exchange pipe communicates with the inlet end of both the water tank heat exchange pipe and the condenser heat exchange pipe through the outlet pipeline, and the inlet end of the evaporator heat exchange pipe communicates with the outlet end of both the water tank heat exchange pipe and the condenser heat exchange pipe through the inlet pipeline.

3. The solute separation device of claim 2, wherein, The freezing water tank is a plurality of tanks separated from each other, the inlet end of the water tank heat exchange pipe of each freezing water tank communicates with the outlet pipeline, and the outlet end of the water tank heat exchange pipe of each freezing water tank communicates with the inlet pipeline.

4. The solute separation device of claim 2 or 3, wherein, The system further comprises a cooling fan and an expansion valve arranged on the outlet pipeline, the inlet pipeline is provided with a first branch pipe at a position outside the evaporator, the outlet pipeline is provided with a second branch pipe at a position outside the condenser, and the cooling fan is arranged opposite to the first branch pipe and the second branch pipe, respectively.

5. The solute separation device of claim 2 or 3, wherein, The system further comprises a gas-liquid separator, a compressor and an oil separator arranged on the inlet pipeline in sequence along the flow direction of the medium in the inlet pipeline.

6. The solute separation device of claim 1, wherein, The evaporator cavity is further provided with a liquid delivery pipe communicating with the evaporator cavity, and the filter container communicates with the liquid delivery pipe.

7. The solute separation device of claim 6, wherein, The steam delivery pipe is located at the top of the evaporator cavity, and the liquid delivery pipe is located at the bottom of the evaporator cavity.

8. The solute separation device of claim 1, wherein, The system further comprises a vacuum system communicating with the condenser cavity.

9. The solute separation device of claim 2, wherein, The evaporator heat exchange pipe, the condenser heat exchange pipe, the water tank heat exchange pipe, the outlet pipeline and the inlet pipeline jointly form a loop for circulating delivery of refrigerant, and the refrigerant circulates in the loop.

10. The solute separation device of claim 9, wherein, The refrigerant in the evaporator heat exchange pipe is in a high-temperature gaseous state, the refrigerant in the water tank heat exchange pipe is in a low-temperature liquid state, and the refrigerant in the condenser heat exchange pipe is in a low-temperature liquid state.

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