A device and method for recycling wastewater from lithium battery positive electrode processing

Abstract

The present application relates to the technical field of recycling and treating wastewater from the processing of positive electrodes of lithium batteries, and discloses a recycling and treating device and method for wastewater from the processing of positive electrodes of lithium batteries, comprising: a collection unit, which comprises a first storage tank and a second storage tank, the first storage tank being used to store phosphorus-containing wastewater, and the second storage tank being used to store lithium-containing wastewater; a reaction unit, which comprises a cell body and a filter press module; the cell body comprises a connected reaction chamber and a sedimentation chamber, a stirring module being installed in the reaction chamber, a horizontally arranged packing layer and a vertically arranged partition being installed in the sedimentation chamber, one side of the packing layer being connected to the partition, and the partition and the packing layer dividing the sedimentation chamber into an upper area and a lower area; the filter press module comprises a diaphragm pump and a filter press, and the lower area is connected to the filter press through the diaphragm pump; a detection unit, which comprises a pH meter, a flow meter and a turbidity meter. The recycling and treating device and method of the present application can make more effective use of residual substances in wastewater and reduce the cost of wastewater recycling.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery positive electrode processing wastewater recovery, and in particular to a device and method for recovering and treating lithium battery positive electrode processing wastewater. Background Art

[0002] On the one hand, the production of lithium battery positive electrodes requires the preparation of iron phosphate. Iron phosphate is typically synthesized through a liquid-phase reaction of ferrous sulfate, hydrogen peroxide, and phosphoric acid under certain conditions. This reaction produces wastewater with a high phosphorus content, which must be treated in a sewage treatment plant before discharge. On the other hand, the production of lithium battery positive electrodes also produces lithium-washing wastewater, which requires pH adjustment and then treatment in an MVR evaporator to recover lithium resources. Therefore, current methods for treating wastewater from lithium battery positive electrode processing fail to effectively utilize phosphorus-containing wastewater, resulting in high recycling costs. Summary of the Invention

[0003] The purpose of this application is to provide a recycling and treatment device and method for lithium battery positive electrode processing wastewater, which can more fully utilize the residual substances in the wastewater and reduce the wastewater recycling cost.

[0004] In order to achieve the above objectives, the present application provides a recycling and treatment device for lithium battery positive electrode processing wastewater, comprising:

[0005] A collection unit comprising a first storage tank and a second storage tank, wherein the first storage tank is used to store phosphorus-containing wastewater, and the second storage tank is used to store lithium-containing wastewater;

[0006] A reaction unit comprising a tank body and a filter press module; the tank body comprises a connected reaction chamber and a sedimentation chamber, the reaction chamber is provided with a stirring module, the sedimentation chamber is provided with a horizontally arranged packing layer and a vertically arranged partition, one side of the packing layer is connected to the partition, the partition and the packing layer separate the sedimentation chamber into an upper area and a lower area, when wastewater is input into the sedimentation chamber, the wastewater passes through the packing layer from the lower area, enters the upper area and is then discharged; the filter press module comprises a diaphragm pump and a filter press, the lower area is connected to the filter press via the diaphragm pump; the reaction unit is provided with two groups, respectively referred to as a first reaction unit and a second reaction unit, the reaction chamber of the first reaction unit is respectively connected to the first storage tank and the second storage tank, and the sedimentation chamber of the first reaction unit is connected to the reaction chamber of the second reaction unit;

[0007] The detection unit includes a pH meter, a flow meter and a turbidity meter. The pH meter is installed in the reaction chamber. Two flow meters are provided and are installed at the outlet of the first storage tank and the outlet of the second storage tank respectively. The turbidity meter is installed in the precipitation chamber.

[0008] In some embodiments, the collection unit further includes a first centrifugal pump and a second centrifugal pump, the first storage tank is connected to the reaction chamber through the first centrifugal pump, and the second storage tank is connected to the reaction chamber through the second centrifugal pump.

[0009] In some embodiments, the cell body further includes a first end cap and a second end cap, wherein the first end cap is sealed on the reaction chamber, and the second end cap is sealed on the precipitation chamber.

[0010] In some embodiments, the stirring module includes a motor, a helical gear reducer and a stirring paddle connected in sequence, the helical gear reducer is installed on the upper part of the first end cover, and the stirring paddle is provided at the lower part of the first end cover.

[0011] In some embodiments, a baffle is installed on the inner wall of the reaction chamber, and the baffle is arranged around the outer periphery of the stirring paddle.

[0012] In some embodiments, the tank body further includes a sludge scraper and suction machine, and the sludge scraper and suction machine is provided on the second end cover.

[0013] In some embodiments, the packing layer is a honeycomb inclined tube packing layer.

[0014] In some embodiments, the tank body further includes a drainage chamber, which is connected to the upper area of ​​the sedimentation chamber. The detection unit further includes a liquid level gauge, which is disposed in the drainage chamber.

[0015] On the other hand, the present application provides a method for recycling and treating lithium battery positive electrode processing wastewater, comprising:

[0016] collecting phosphorus-containing wastewater through a first storage tank and collecting lithium-containing wastewater through a second storage tank;

[0017] The first storage tank and the second storage tank are opened to transport the phosphorus-containing wastewater and the lithium-containing wastewater into the reaction chamber of the first reaction unit, and the stirring module is started to obtain mixed wastewater. The pH value of the mixed wastewater is adjusted to 8 to 10, and then the mixed wastewater flows into the sedimentation chamber of the first reaction unit. After filtering through the packing layer in the sedimentation chamber, magnesium phosphate is precipitated in the lower area of ​​the sedimentation chamber, and filtered wastewater is formed in the upper area of ​​the sedimentation chamber.

[0018] The upper area of ​​the sedimentation chamber of the first reaction unit is opened to transport the filtered wastewater into the reaction chamber of the second reaction unit. The stirring module is started to adjust the pH value of the filtered wastewater to 11-13, and then the filtered wastewater flows into the sedimentation chamber of the second reaction unit. After filtering through the packing layer in the sedimentation chamber, lithium phosphate is precipitated in the lower area of ​​the sedimentation chamber and discharged as clear water in the upper area of ​​the sedimentation chamber.

[0019] The diaphragm pumps of the first reaction unit and the second reaction unit are started to transport magnesium phosphate and lithium phosphate into the filter press respectively, and the magnesium phosphate filter cake and the lithium phosphate filter cake are obtained by squeezing.

[0020] In some embodiments, the pH value of the mixed wastewater and the filtered wastewater is adjusted by injecting liquid alkali.

[0021] The present application provides a device for recycling and treating wastewater from lithium battery positive electrode processing. Compared with the prior art, its beneficial effects are:

[0022] The first storage tank is used to store phosphorus-containing wastewater, and the second storage tank is used to store lithium-containing wastewater. Both wastewaters are generated during the processing of lithium battery positive electrodes; the reaction unit includes a tank body and a filter press module. The two wastewaters are mixed in the tank body to react and form a precipitate, which is then squeezed through the filter press module to obtain magnesium phosphate filter cake and lithium phosphate filter cake, so that the materials in the wastewater can be effectively recovered, the residual substances in the wastewater can be more fully utilized, and the wastewater recovery cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the overall structure of the lithium battery positive electrode processing wastewater recovery and treatment device provided in an embodiment of the present application.

[0024] Figure 2 This is a schematic diagram of the enlarged structure of the cell body of the first reaction unit of the lithium battery positive electrode processing wastewater recovery and treatment device provided in an embodiment of the present application.

[0025] Figure 3 This is an enlarged structural schematic diagram of the filter press module of the lithium battery positive electrode processing wastewater recovery and treatment device provided in an embodiment of the present application.

[0026] Figure 4 This is a schematic diagram of the enlarged structure of the stirring module of the lithium battery positive electrode processing wastewater recovery and treatment device provided in an embodiment of the present application.

[0027] Figure 5 It is the molar concentration of lithium ions, magnesium ions and phosphate ions in the solution at different pH values.

[0028] In the figure: 100, recycling and processing device; 1, collecting unit; 11, first storage tank; 12, second storage tank; 2, reaction unit; 21, tank body; 210, drainage chamber; 211, reaction chamber; 212, sedimentation chamber; 212a, upper area; 212b, lower area; 213, stirring module; 2131, motor; 2132, helical gear reducer; 2133, stirring paddle; 214, packing layer; 215, partition; 216, first end cover; 217, second end cover; 218, baffle; 219, scraper and suction machine; 23, filter press module; 231, diaphragm pump; 232, filter press; 3, detection unit; 31, pH meter; 32, flow meter; 33, turbidity meter; 34, liquid level meter. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0030] It should be understood that in the description of this application, the terms "upper", "lower", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated, that is, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In addition, unless otherwise specified, "multiple" means two or more.

[0031] like Figure 1-4As shown, a recycling and treatment device 100 for lithium battery positive electrode processing wastewater provided by an embodiment of the present application includes: a collection unit 1, including a first storage tank 11 and a second storage tank 12, the first storage tank 11 is used to store phosphorus-containing wastewater, and the second storage tank 12 is used to store lithium-containing wastewater; a reaction unit 2, which includes a cell body 21 and a filter press module 23; the cell body 21 includes a reaction chamber 211 and a sedimentation chamber 212 connected to each other, a stirring module 213 is installed in the reaction chamber 211, and a horizontally arranged packing layer 214 and a vertically arranged partition 215 are installed in the sedimentation chamber 212, one side of the packing layer 214 is connected to the partition 215, and the partition 215 is connected to the packing layer 214. The sedimentation chamber 212 is divided into an upper area 212a and a lower area 212b. When wastewater is input into the sedimentation chamber 212, the wastewater passes through the packing layer 214 from the lower area 212b, enters the upper area 212a, and is discharged. The filter press module 23 includes a diaphragm pump 231 and a filter press 232. The lower area 212b is connected to the filter press 232 via the diaphragm pump 231. The reaction unit 2 has two groups, respectively designated as a first reaction unit and a second reaction unit. The reaction chamber 211 of the first reaction unit is connected to the first storage tank 11 and the second storage tank 12, respectively. The sedimentation chamber 212 of the first reaction unit is connected to the reaction chamber 211 of the second reaction unit.

[0032] The detection unit 3 includes a pH meter 31, a flow meter 32 and a turbidity meter 33. The pH meter 31 is installed in the reaction chamber 211. Two flow meters 32 are provided and are installed at the outlet of the first storage tank 11 and the outlet of the second storage tank 12 respectively. The turbidity meter 33 is installed in the sedimentation chamber.

[0033] Based on the above-mentioned setting, the first storage tank 11 is used to store phosphorus-containing wastewater, and the second storage tank 12 is used to store lithium-containing wastewater. Both wastewaters are wastewater generated during the processing of lithium battery positive electrodes; the reaction unit 2 includes a cell body 21 and a filter press module 23. The two wastewaters are mixed in the cell body 21 for reaction, and the filter press module 23 is used to press to obtain magnesium phosphate filter cake and lithium phosphate filter cake, so that the materials in the wastewater can be effectively recovered, the residual substances in the wastewater can be more fully utilized, and the wastewater recovery cost can be reduced.

[0034] In one embodiment, the collection unit 1 further includes a first centrifugal pump and a second centrifugal pump. The first storage tank 11 is connected to the reaction chamber 211 via the first centrifugal pump, and the second storage tank 12 is connected to the reaction chamber 211 via the second centrifugal pump. The first centrifugal pump and the second centrifugal pump can stably transport the wastewater in the first storage tank 11 and the second storage tank 12 to the reaction chamber 211 of the first reaction unit.

[0035] like Figure 2As shown, the cell body 21 further includes a first end cap 216 and a second end cap 217. The first end cap 216 is sealed on the reaction chamber 211, and the second end cap 217 is sealed on the sedimentation chamber 212. The first end cap 216 and the second end cap 217 are provided to prevent the wastewater in the reaction chamber 211 and the sedimentation chamber 212 from leaking out during the reaction process.

[0036] Specifically, such as Figure 4 As shown, the stirring module 213 includes a motor 2131, a helical gear reducer 2132 and a stirring paddle 2133 connected in sequence. The helical gear reducer 2132 is installed on the upper part of the first end cover 216, and the stirring paddle 2133 is arranged at the lower part of the first end cover 216, so that the installation structure of the stirring module 213 is stable; when working, the starting motor 2131 is adjusted through the helical gear reducer 2132 to increase the available output torque without increasing the power consumption of the motor 2131, so that the stirring paddle 2133 can stir and mix the wastewater in the reaction chamber 211.

[0037] Optionally, a baffle 218 is installed on the inner wall of the reaction chamber 211, and the baffle 218 is arranged around the outer periphery of the stirring paddle 2133. The baffle 218 has an anti-swirl effect, making the mixing of the wastewater more uniform.

[0038] In one embodiment, the tank body 21 further includes a sludge scraper 219, which is provided on the second end cover 217. The sludge scraper 219 is used to maintain and clean the tank body 21 when the tank body 21 is not in use.

[0039] Specifically, the packing layer 214 is a honeycomb inclined tube packing layer. When the wastewater passes through the honeycomb inclined tube packing layer, it forms a swirling flow, which creates a large contact area between the sediment and the liquid, thereby accelerating the sedimentation.

[0040] In one embodiment, the pool body 21 also includes a drainage chamber 210, which is connected to the upper area 212a of the sedimentation chamber 212, wherein the liquid in the drainage chamber 210 of the first reaction unit flows into the reaction chamber 211 of the second reaction unit, and the detection unit 3 also includes a liquid level gauge 34, which is arranged in the drainage chamber 210, and the liquid level gauge 34 is used to detect the liquid level height of the drainage chamber 210; according to actual needs, the liquid level gauge 34 can also be installed in the first storage tank 11, the second storage tank 12 and the reaction chamber 211 to measure the liquid level height.

[0041] Another embodiment of the application provides a method for recycling and treating lithium battery positive electrode processing wastewater, comprising:

[0042] Phosphorus-containing wastewater is collected by the first storage tank 11, and lithium-containing wastewater is collected by the second storage tank 12. It should be noted that phosphorus-containing wastewater is generated during the preparation of ferric phosphate, which is typically synthesized by a liquid-phase reaction of ferrous sulfate, hydrogen peroxide, and phosphoric acid under certain conditions. This reaction produces wastewater with a high phosphorus content. Lithium-containing wastewater is generated during the lithium washing process and also contains magnesium ions.

[0043] The first storage tank 11 and the second storage tank 12 are opened to transport the phosphorus-containing wastewater and the lithium-containing wastewater into the reaction chamber 211 of the first reaction unit, and the stirring module 213 is started to obtain mixed wastewater. The pH value of the mixed wastewater is adjusted to 8-10 and then flows into the sedimentation chamber 212 of the first reaction unit. After being filtered through the filler layer 214 in the sedimentation chamber 212, magnesium phosphate is precipitated in the lower area 212b of the sedimentation chamber 212, and filtered wastewater is formed in the upper area 212a of the sedimentation chamber 212.

[0044] The upper area 212a of the sedimentation chamber 212 of the first reaction unit is opened to transport the filtered wastewater to the reaction chamber 211 of the second reaction unit, and the stirring module 213 is started to adjust the pH value of the filtered wastewater to 11-13 and then flow into the sedimentation chamber 212 of the second reaction unit. After being filtered through the filler layer 214 in the sedimentation chamber 212, lithium phosphate is precipitated in the lower area 212b of the sedimentation chamber 212, and clean water is formed and discharged in the upper area 212a of the sedimentation chamber 212. After the clean water is discharged into the drainage chamber 210, the pH value of the clean water is adjusted to 6-9 (optionally 7) by injecting acidic substances before being discharged.

[0045] according to Figure 5 As shown, by comparing the molar concentrations of lithium ions, magnesium ions, and phosphate ions in the solution at different pH values ​​(the lower the molar concentration, the more precipitate in the solution), it can be seen that when magnesium phosphate is precipitated, the pH value can be optionally adjusted to 9; when lithium phosphate is precipitated, the pH value can be optionally adjusted to 12. Through the above steps, magnesium phosphate and lithium phosphate are precipitated in the precipitation chambers 212 of the first reaction unit and the second reaction unit, respectively.

[0046] In another embodiment, the diaphragm pumps 231 of the first and second reaction units are activated to transport magnesium phosphate and lithium phosphate to filter presses 232, respectively, for compression to produce magnesium phosphate and lithium phosphate filter cakes. Diaphragm pumps 231 are pneumatic diaphragm pumps, and filter presses 232 are membrane filter presses. Wastewater generated after the filtration operation in the membrane filter presses of the first and second reaction units is transported to the sedimentation chambers 212 of the first and second reaction units for reuse.

[0047] In another embodiment, the pH value of the mixed wastewater and the filtered wastewater is adjusted by injecting liquid alkali.

[0048] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and replacements can be made without departing from the technical principles of the present application. These improvements and replacements should also be regarded as the scope of protection of the present application.

Claims

1. A method for recycling and treating lithium battery positive electrode processing wastewater, characterized in that: include: collecting phosphorus-containing wastewater through a first storage tank and collecting lithium-containing wastewater through a second storage tank; The lithium-containing wastewater also contains magnesium ions; Opening the first storage tank and the second storage tank to transport the phosphorus-containing wastewater and the lithium-containing wastewater into the reaction chamber of the first reaction unit, starting the stirring module of the first reaction unit to obtain mixed wastewater, adjusting the pH value of the mixed wastewater to 8-10, and then flowing the mixed wastewater into the precipitation chamber of the first reaction unit. After filtering through the packing layer in the precipitation chamber of the first reaction unit, magnesium phosphate is precipitated in the lower area of ​​the precipitation chamber of the first reaction unit, and filtered wastewater is formed in the upper area of ​​the precipitation chamber of the first reaction unit; The upper region of the sedimentation chamber of the first reaction unit is opened to transport the filtered wastewater into the reaction chamber of the second reaction unit, the stirring module of the second reaction unit is started to adjust the pH value of the filtered wastewater to 11-13, and then the filtered wastewater flows into the sedimentation chamber of the second reaction unit. After filtering through the packing layer in the sedimentation chamber of the second reaction unit, lithium phosphate is precipitated in the lower region of the sedimentation chamber of the second reaction unit, and clear water is discharged from the upper region of the sedimentation chamber of the second reaction unit; The diaphragm pumps of the first reaction unit and the second reaction unit are started to transport magnesium phosphate and lithium phosphate to the filter presses corresponding to the first reaction unit and the second reaction unit respectively, and the magnesium phosphate filter cake and the lithium phosphate filter cake are obtained by squeezing.

2. The method for recycling lithium battery positive electrode processing wastewater according to claim 1, characterized in that: When adjusting the pH value of the mixed wastewater and the filtered wastewater, it is done by injecting liquid alkali.

3. The method for recycling lithium battery positive electrode processing wastewater according to claim 1 or 2, characterized in that: A lithium battery positive electrode processing wastewater recovery and treatment device is used to recover and treat the lithium battery positive electrode processing wastewater, and the lithium battery positive electrode processing wastewater recovery and treatment device includes: A collection unit comprising a first storage tank and a second storage tank, wherein the first storage tank is used to store phosphorus-containing wastewater and the second storage tank is used to store lithium-containing wastewater; A reaction unit comprising a tank body and a filter press module; the tank body comprises a connected reaction chamber and a sedimentation chamber, the reaction chamber is provided with a stirring module, the sedimentation chamber is provided with a horizontally arranged packing layer and a vertically arranged partition, one side of the packing layer is connected to the partition, the partition and the packing layer separate the sedimentation chamber into an upper area and a lower area, when wastewater is input into the sedimentation chamber, the wastewater passes through the packing layer from the lower area, enters the upper area and is then discharged; the filter press module comprises a diaphragm pump and a filter press, the lower area is connected to the filter press via the diaphragm pump; the reaction unit is provided with two groups, respectively referred to as a first reaction unit and a second reaction unit, the reaction chamber of the first reaction unit is respectively connected to the first storage tank and the second storage tank, and the sedimentation chamber of the first reaction unit is connected to the reaction chamber of the second reaction unit; The detection unit includes a pH meter, a flow meter and a turbidity meter. The pH meter is installed in the reaction chamber. Two flow meters are provided and are installed at the outlet of the first storage tank and the outlet of the second storage tank respectively. The turbidity meter is installed in the precipitation chamber.

4. The method for recycling lithium battery cathode processing wastewater according to claim 3, characterized in that: The collection unit further includes a first centrifugal pump and a second centrifugal pump. The first storage tank is connected to the reaction chamber of the first reaction unit through the first centrifugal pump, and the second storage tank is connected to the reaction chamber of the first reaction unit through the second centrifugal pump.

5. The method for recycling lithium battery cathode processing wastewater according to claim 3, characterized in that: The cell body further includes a first end cover and a second end cover, wherein the first end cover is sealed on the reaction chamber, and the second end cover is sealed on the precipitation chamber.

6. The method for recycling lithium battery cathode processing wastewater according to claim 5, characterized in that: The stirring module includes a motor, a helical gear reducer and a stirring paddle which are connected in sequence. The helical gear reducer is installed on the upper part of the first end cover, and the stirring paddle is arranged on the lower part of the first end cover.

7. The method for recycling lithium battery cathode processing wastewater according to claim 6, characterized in that: A baffle is installed on the inner wall of the reaction chamber, and the baffle is arranged around the outer periphery of the stirring paddle.

8. The method for recycling lithium battery cathode processing wastewater according to claim 5, characterized in that: The pool body further comprises a sludge scraper and suction machine, which is arranged on the second end cover.

9. The method for recycling lithium battery cathode processing wastewater according to claim 3, characterized in that: The packing layer is a honeycomb inclined tube packing layer.

10. The method for recycling lithium battery cathode processing wastewater according to claim 3, characterized in that: The tank body further includes a drainage chamber, which is communicated with the upper area of ​​the sedimentation chamber. The detection unit further includes a liquid level gauge, which is arranged in the drainage chamber.

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