A wastewater treatment system for ferric phosphate production

Abstract

This invention provides a wastewater treatment system for ferric phosphate production, comprising: a mother liquor wastewater collection tank, a first pH adjustment tank, a filter press, a second pH adjustment tank, a first sedimentation tank, a first membrane filtration device, a first multi-stage reverse osmosis device, an evaporation device, and a wash wastewater collection tank, a third pH adjustment tank, a second sedimentation tank, a second membrane filtration device, a second multi-stage reverse osmosis device, and a second-stage reverse osmosis device. This invention, by setting up the first and second pH adjustment tanks, can separately precipitate heavy metals and magnesium ammonium phosphate; through multi-stage membrane filtration and membrane concentration, it achieves wastewater reuse while concentrating the wastewater, reducing the investment and operating costs of the evaporation device; furthermore, by evaporating the wastewater through the evaporation device, it truly achieves zero wastewater discharge.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, and in particular relates to a wastewater treatment system for ferric phosphate production. Background Technology

[0002] Green lithium-ion power batteries, integrating energy saving, environmental protection, and recyclability, are currently the most compliant clean energy source in China. They are mainly used in electric vehicles, communications, homes, energy storage devices, instruments, and model aircraft. Lithium batteries account for a significant portion of the cost of new energy vehicles, approximately 40%. Iron phosphate is also an ideal precursor material for the cathode materials of in-vehicle lithium-ion power batteries, grid energy storage batteries, and power tool batteries.

[0003] The traditional method for synthesizing ferric phosphate involves reacting divalent ferric salts (such as ferrous sulfate) with ammonium hydrogen phosphate, phosphoric acid, ammonia, hydrogen peroxide, etc. This process generates two streams of acidic wastewater: wash water and mother liquor. Both streams contain high levels of ammonia nitrogen, heavy metals, and phosphorus, making wastewater treatment extremely difficult. Discharge of this wastewater can cause significant impacts and harm to the surrounding natural environment. Utility Model Content

[0004] The purpose of this invention is to provide a wastewater treatment system for ferric phosphate production.

[0005] Therefore, the above-mentioned objective of this utility model is achieved through the following technical solution:

[0006] A wastewater treatment system for ferric phosphate production includes:

[0007] The system includes a mother liquor wastewater collection tank, a first pH adjustment tank, a filter press, a second pH adjustment tank, a first sedimentation tank, a first membrane filtration unit, a first multi-stage reverse osmosis unit, an evaporation unit, and...

[0008] Washing wastewater collection tank, third pH adjustment tank, second sedimentation tank, second membrane filtration device, second multi-stage reverse osmosis device, and second-stage reverse osmosis device;

[0009] The outlet of the mother liquor wastewater collection tank is connected to the first pH adjustment tank, which is equipped with an ammonia dosing device. The outlet of the first pH adjustment tank is connected to the inlet of the filter press, and the inlet of the second pH adjustment tank is connected to the filtrate outlet of the filter press. The second pH adjustment tank is equipped with an ammonia dosing device and a magnesium dosing device. The outlet of the second pH adjustment tank is connected to the first sedimentation tank, the supernatant outlet of the first sedimentation tank is connected to the inlet of the first membrane filtration device, the product water outlet of the first membrane filtration device is connected to the inlet of the first multi-stage reverse osmosis device, and the concentrate outlet of the first multi-stage reverse osmosis device is connected to the inlet of the evaporation device.

[0010] The outlet of the wastewater collection tank is connected to the third pH adjustment tank, which is equipped with an ammonia dosing device. The outlet of the third pH adjustment tank is connected to the second sedimentation tank. The supernatant outlet of the second sedimentation tank is connected to the inlet of the second membrane filtration device. The product water outlet of the second membrane filtration device is connected to the inlet of the second multi-stage reverse osmosis device. The product water outlet of the second multi-stage reverse osmosis device is connected to the inlet of the secondary reverse osmosis device.

[0011] While adopting the above technical solutions, this utility model may also adopt or combine the following technical solutions:

[0012] As a preferred technical solution of this utility model: the product water pipeline of the first membrane filtration device is provided with an acid dosing port.

[0013] As a preferred technical solution of this utility model: the first membrane filtration device is one of a multi-media filter, an ultrafiltration device, a microfiltration device, or a ceramic membrane device.

[0014] As a preferred technical solution of this utility model: the product water pipeline of the second membrane filtration device is provided with an acid dosing port.

[0015] As a preferred technical solution of this utility model: the second membrane filtration device is one of a multi-media filter, an ultrafiltration device, a microfiltration device, or a ceramic membrane device.

[0016] As a preferred technical solution of this utility model: the concentrate outlet of the second multi-stage reverse osmosis device is connected to the inlet of the first membrane filtration device.

[0017] As a preferred technical solution of this utility model: the concentrate outlet of the secondary reverse osmosis device is connected to the inlet of the second multi-stage reverse osmosis device.

[0018] As a preferred technical solution of this utility model: the second multi-stage reverse osmosis device is one of brackish water reverse osmosis device, seawater desalination reverse osmosis device, ultra-high pressure reverse osmosis device, and disc tube reverse osmosis device.

[0019] As a preferred technical solution of this utility model: the first multi-stage reverse osmosis device is one of brackish water reverse osmosis device, seawater desalination reverse osmosis device, ultra-high pressure reverse osmosis device, and disc tube reverse osmosis device.

[0020] As a preferred technical solution of this utility model: the evaporation device is one of a mechanical vapor recompression evaporator, a falling film evaporator, a forced circulation evaporator, or a multi-effect evaporator.

[0021] This invention provides a wastewater treatment system for ferric phosphate production. By setting up a first pH adjustment tank and a second pH adjustment tank, heavy metals and magnesium ammonium phosphate can be precipitated separately. Through multi-stage membrane filtration and membrane concentration, wastewater can be reused while concentrating the wastewater, reducing the investment and operating costs of the evaporation device. In addition, the wastewater is evaporated through the evaporation device, truly achieving zero wastewater discharge. Attached Figure Description

[0022] Figure 1 This is a structural diagram of the ferric phosphate production wastewater treatment system provided by this utility model. Detailed Implementation

[0023] The present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

[0024] The water quality of the wash water and mother liquor is shown in Table 1 below.

[0025] Table 1

[0026]

[0027] A wastewater treatment system for ferric phosphate production includes:

[0028] The system includes a mother liquor wastewater collection tank 101, a first pH adjustment tank 102, a filter press 103, a second pH adjustment tank 104, a first sedimentation tank 105, a first membrane filtration device 106, a first multi-stage reverse osmosis device 107, an evaporator 108, and...

[0029] Washing wastewater collection tank 201, third pH adjustment tank 202, second sedimentation tank 203, second membrane filtration device 204, second multi-stage reverse osmosis device 205, and second-stage reverse osmosis device 206;

[0030] The outlet of the mother liquor wastewater collection tank 101 is connected to the first pH adjustment tank 102, which is equipped with an ammonia dosing device. The outlet of the first pH adjustment tank 102 is connected to the inlet of the filter press 103. The inlet of the second pH adjustment tank 104 is connected to the filtrate outlet of the filter press 103, which is equipped with an ammonia dosing device and a magnesium dosing device. The outlet of the second pH adjustment tank 104 is connected to the first sedimentation tank 105. The supernatant outlet of the first sedimentation tank 105 is connected to the inlet of the first membrane filtration device 106. The product water outlet of the first membrane filtration device 106 is connected to the inlet of the first multi-stage reverse osmosis device 107. The concentrate outlet of the first multi-stage reverse osmosis device 107 is connected to the inlet of the evaporator 108.

[0031] The outlet of the wastewater collection tank 201 is connected to the third pH adjustment tank 202, which is equipped with an ammonia dosing device. The outlet of the third pH adjustment tank 202 is connected to the second sedimentation tank 203. The supernatant outlet of the second sedimentation tank 203 is connected to the inlet of the second membrane filtration device 204. The product water outlet of the second membrane filtration device 204 is connected to the inlet of the second multi-stage reverse osmosis device 205. The product water outlet of the second multi-stage reverse osmosis device 205 is connected to the inlet of the second-stage reverse osmosis device 206.

[0032] In this embodiment, an acid dosing port is provided on the product water pipeline of the first membrane filtration device 106.

[0033] In this embodiment, the first membrane filtration device 106 is one of a multi-media filter, an ultrafiltration device, a microfiltration device, or a ceramic membrane device.

[0034] In this embodiment, an acid dosing port is provided on the product water pipeline of the second membrane filtration device 204.

[0035] In this embodiment, the second membrane filtration device 204 is one of a multi-media filter, an ultrafiltration device, a microfiltration device, or a ceramic membrane device.

[0036] In this embodiment: the concentrate outlet of the second multi-stage reverse osmosis device 205 is connected to the inlet of the first membrane filtration device 106.

[0037] In this embodiment, the concentrate outlet of the secondary reverse osmosis unit 206 is connected to the inlet of the second multi-stage reverse osmosis unit 205.

[0038] In this embodiment: the second multi-stage reverse osmosis device 205 is one of a brackish water reverse osmosis device, a seawater desalination reverse osmosis device, an ultra-high pressure reverse osmosis device, or a disc tube reverse osmosis device.

[0039] In this embodiment: the first multi-stage reverse osmosis device 107 is one of a brackish water reverse osmosis device, a seawater desalination reverse osmosis device, an ultra-high pressure reverse osmosis device, and a disc tube reverse osmosis device.

[0040] In this embodiment, the evaporation device 108 is one of a mechanical vapor recompression evaporator, a falling film evaporator, a forced circulation evaporator, or a multi-effect evaporator.

[0041] Specifically, the treatment process of the ferric phosphate production wastewater treatment system provided by this utility model is as follows:

[0042] It is divided into two treatment routes: wash water treatment and mother liquor treatment;

[0043] Washing treatment:

[0044] (1) After the wash water enters the wash wastewater collection tank for homogenization, it is then transported to the third pH adjustment tank. Ammonia water is evenly added to the third pH adjustment tank through the ammonia water dosing device. The pH is controlled at 6.5-9. After stirring and reacting for 30-60 minutes, it is transported to the second sedimentation tank for metal precipitation to remove heavy metal ions.

[0045] (2) The supernatant from the second sedimentation tank is filtered by the second membrane filtration device to remove suspended solids and colloids;

[0046] (3) An acid dosing port is provided on the product water pipeline of the second membrane filtration device. Acid is added to adjust the pH. After the pH of the product water of the second membrane filtration device is adjusted (pH is controlled at 3-7), it is then transported to the second multi-stage reverse osmosis device for concentration. When the concentration at the end of the concentration is the same as that of the mother liquor, the concentrated water is transported to the inlet of the first multi-stage reverse osmosis device of the mother liquor.

[0047] (4) The permeate from the second multi-stage reverse osmosis unit enters the second-stage reverse osmosis unit for further filtration. The permeate from the second-stage reverse osmosis unit is then reused as the final permeate. The concentrate from the second-stage reverse osmosis unit is then returned to the inlet of the second multi-stage reverse osmosis unit.

[0048] Mother liquor treatment:

[0049] (1) After the mother liquor enters the mother liquor wastewater collection tank for homogenization, it is then transported to the first pH adjustment tank. Ammonia water is evenly added to the first pH adjustment tank through the ammonia water dosing device. The pH is controlled at 3.5-6.5. After stirring and reacting for 30-60 minutes, it is transported to the filter press to remove heavy metal ions.

[0050] (2) The filter press filtrate is transported to the second pH adjustment tank. Ammonia and magnesium are added evenly to the second pH adjustment tank through the ammonia dosing device and the magnesium dosing device. The pH is controlled at 6.5-9. After stirring and reacting for 30-60 minutes, it is transported to the first sedimentation tank for ammonium magnesium phosphate precipitation to obtain the finished ammonium magnesium phosphate product.

[0051] (3) The supernatant from the first sedimentation tank is filtered through the first membrane filtration device to remove suspended solids and colloids;

[0052] (4) An acid dosing port is provided on the product water pipeline of the first membrane filtration device. Acid is added to adjust the pH. After the pH of the product water of the first membrane filtration device is adjusted (pH is controlled at 3-7), it is then sent to the first multi-stage reverse osmosis device for concentration. The mother liquor is finally concentrated to 12%-17% through the first multi-stage reverse osmosis device and then sent to the evaporation device for evaporation and crystallization to prepare ammonium sulfate crystals.

[0053] (5) The permeate from the first multi-stage reverse osmosis unit is mixed with the permeate from the second multi-stage reverse osmosis unit and then enters the second-stage reverse osmosis unit.

[0054] The above specific implementation examples are used to explain and illustrate this utility model, and are only preferred embodiments of this utility model, not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made to this utility model within the spirit and scope of the claims shall fall within the protection scope of this utility model.

Claims

1. A wastewater treatment system for ferric phosphate production, characterized in that: include: The system includes a mother liquor wastewater collection tank, a first pH adjustment tank, a filter press, a second pH adjustment tank, a first sedimentation tank, a first membrane filtration unit, a first multi-stage reverse osmosis unit, an evaporation unit, and... Washing wastewater collection tank, third pH adjustment tank, second sedimentation tank, second membrane filtration device, second multi-stage reverse osmosis device, and second-stage reverse osmosis device; The outlet of the mother liquor wastewater collection tank is connected to the first pH adjustment tank, which is equipped with an ammonia dosing device. The outlet of the first pH adjustment tank is connected to the inlet of the filter press, and the inlet of the second pH adjustment tank is connected to the filtrate outlet of the filter press. The second pH adjustment tank is equipped with an ammonia dosing device and a magnesium dosing device. The outlet of the second pH adjustment tank is connected to the first sedimentation tank, the supernatant outlet of the first sedimentation tank is connected to the inlet of the first membrane filtration device, the product water outlet of the first membrane filtration device is connected to the inlet of the first multi-stage reverse osmosis device, and the concentrate outlet of the first multi-stage reverse osmosis device is connected to the inlet of the evaporation device. The outlet of the wastewater collection tank is connected to the third pH adjustment tank, which is equipped with an ammonia dosing device. The outlet of the third pH adjustment tank is connected to the second sedimentation tank. The supernatant outlet of the second sedimentation tank is connected to the inlet of the second membrane filtration device. The product water outlet of the second membrane filtration device is connected to the inlet of the second multi-stage reverse osmosis device. The product water outlet of the second multi-stage reverse osmosis device is connected to the inlet of the secondary reverse osmosis device.

2. The ferric phosphate production wastewater treatment system according to claim 1, characterized in that: The first membrane filtration device has an acid dosing port on its product water pipeline.

3. The ferric phosphate production wastewater treatment system according to claim 1 or 2, characterized in that: The first membrane filtration device is one of a multi-media filter, an ultrafiltration device, a microfiltration device, or a ceramic membrane device.

4. The ferric phosphate production wastewater treatment system according to claim 1, characterized in that: The product water pipeline of the second membrane filtration device is equipped with an acid dosing port.

5. The ferric phosphate production wastewater treatment system according to claim 1 or 4, characterized in that: The second membrane filtration device is one of a multi-media filter, an ultrafiltration device, a microfiltration device, or a ceramic membrane device.

6. The ferric phosphate production wastewater treatment system according to claim 1, characterized in that: The concentrate outlet of the second multi-stage reverse osmosis unit is connected to the inlet of the first membrane filtration unit.

7. The ferric phosphate production wastewater treatment system according to claim 1, characterized in that: The concentrate outlet of the secondary reverse osmosis unit is connected to the inlet of the second multi-stage reverse osmosis unit.

8. The ferric phosphate production wastewater treatment system according to claim 1, 6, or 7, characterized in that: The second multi-stage reverse osmosis device is one of the following: brackish water reverse osmosis device, seawater desalination reverse osmosis device, ultra-high pressure reverse osmosis device, and disc tube reverse osmosis device.

9. The ferric phosphate production wastewater treatment system according to claim 1, characterized in that: The first multi-stage reverse osmosis device is one of the following: brackish water reverse osmosis device, seawater desalination reverse osmosis device, ultra-high pressure reverse osmosis device, and disc tube reverse osmosis device.

10. The ferric phosphate production wastewater treatment system according to claim 1, characterized in that: The evaporation device is one of a mechanical vapor recompression evaporator, a falling film evaporator, a forced circulation evaporator, or a multi-effect evaporator.

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