Magnesium sulfate wastewater treatment system

Abstract

The application discloses a magnesium sulfate wastewater treatment system, which comprises a raw water tank, a heavy metal removal device, an alkaline precipitation mechanism, a first sedimentation filter press and an acid precipitation device arranged in sequence. The heavy metal removal device is used for removing metal impurities in the wastewater; the alkaline precipitation mechanism is connected with a liquid phase outlet of the heavy metal removal device and used for alkaline precipitation of the wastewater; and the acid precipitation device is used for acid precipitation of the wastewater. The magnesium sulfate wastewater treatment system further comprises a separation mechanism, an input end of the separation mechanism is connected with a liquid phase outlet of the first sedimentation filter press, an output end of the separation mechanism is divided into a first branch and a second branch, the first branch is connected with the alkaline precipitation mechanism, the second branch is connected with the acid precipitation device, and a flow rate of the first branch is greater than that of the second branch. The magnesium sulfate wastewater treatment system can realize magnesium sulfate wastewater treatment, ensure stable treatment effect, and effectively improve the removal effect of metal ions by arranging the separation mechanism.

Description

Technical Field

[0001] This application belongs to the field of wastewater treatment technology, specifically relating to a magnesium sulfate wastewater treatment system. Background Technology

[0002] Magnesium sulfate wastewater generated during rare earth smelting is specifically as follows: In rare earth hydrometallurgy, magnesium salt saponification P507 is used as the initial organic phase for the first stage extraction, and a calcium-magnesium sulfate rare earth solution is used as the initial aqueous phase for the final stage extraction. After multiple stages of extraction, the aqueous phase after the first stage extraction is magnesium sulfate wastewater.

[0003] Existing methods for treating magnesium sulfate wastewater involve membrane separation, which utilizes the selective permeability of membranes to separate magnesium sulfate from other components in the wastewater. For example, microfiltration is first used to remove fine particulate impurities, followed by nanofiltration to obtain a permeate with low magnesium sulfate content and a concentrate with high magnesium sulfate content. However, for wastewater with complex compositions, such as wastewater containing a large amount of metal ions, the membrane system cannot effectively separate magnesium sulfate from heavy metals, affecting the treatment efficiency. Utility Model Content

[0004] Therefore, it is necessary to provide a magnesium sulfate wastewater treatment system that can treat magnesium sulfate wastewater and ensure stable treatment results.

[0005] The technical solution proposed in this application is as follows: A magnesium sulfate wastewater treatment system, comprising: Raw water tank; A gravimetric device is installed downstream of the raw water tank to remove metal impurities from the wastewater. An alkaline precipitation mechanism is located downstream of the gravimetric dewatering device and connected to the liquid phase outlet of the gravimetric dewatering device, and is used for alkaline precipitation of wastewater. The first precipitation filter press is located downstream of the alkaline precipitation mechanism; An acid precipitation device is installed downstream of the first precipitation filter press and is used to perform acid precipitation on wastewater. The flow splitting mechanism has an input end connected to the liquid phase outlet of the first precipitation filter press, and an output end divided into a first branch and a second branch. The first branch is connected to the alkaline precipitation reaction mechanism, and the second branch is connected to the acidic precipitation device. The flow rate of the first branch is greater than that of the second branch.

[0006] The aforementioned magnesium sulfate wastewater treatment system removes most metal impurities through a gravimetric analyzer, followed by sequential removal of metal impurities from the wastewater through an alkaline precipitation unit and an acidic precipitation unit. In the alkaline precipitation unit, ammonia is added to form ammonium sulfate. After separating the precipitate and liquid, the system ensures that the liquid contains a large amount of ammonium sulfate with extremely low metal ion content, thus achieving stable treatment results while treating magnesium sulfate wastewater. Furthermore, the diversion mechanism effectively enhances the removal of metal ions.

[0007] Furthermore, the degravation device includes a degravation reaction mechanism and a degravation filter press arranged sequentially downstream of the raw water tank. The degravation reaction mechanism is used to precipitate metal impurities in the wastewater, and the alkaline precipitation mechanism is connected to the liquid phase outlet of the degravation filter press.

[0008] Furthermore, the degravation device also includes a degravation transfer pump, which is disposed between the degravation reaction mechanism and the degravation filter press.

[0009] Furthermore, the alkaline precipitation mechanism includes an alkaline reaction vessel and an alkali supply module. The alkaline reaction vessel is connected to the liquid phase outlet of the degravation device, and the alkali supply module is connected to the alkaline reaction vessel for feeding ammonia water into the alkaline reaction vessel. The first branch is connected to the alkaline reaction vessel.

[0010] Furthermore, the acid precipitation device includes a pH adjustment mechanism and an acid precipitation mechanism sequentially disposed downstream of the diversion mechanism. The pH adjustment mechanism is connected to the second branch and is used to adjust the pH of the wastewater. The acid precipitation mechanism is used to perform acid precipitation on the pH-adjusted wastewater.

[0011] Furthermore, the pH adjustment mechanism includes a pH adjustment tank and a first acid supply module. The second branch and the first acid supply module are both connected to the pH adjustment tank. The first acid supply module is used to input dilute sulfuric acid into the pH adjustment tank. The acid precipitation mechanism is connected to the pH adjustment tank.

[0012] Furthermore, the acid precipitation mechanism includes an acid reaction vessel and a second acid supply module. Both the pH adjustment mechanism and the second acid supply module are connected to the acid reaction vessel. The second acid supply module is used to input oxalic acid into the acid reaction vessel.

[0013] Furthermore, the acid precipitation apparatus also includes a second precipitation filter press, which is located downstream of the acid precipitation mechanism.

[0014] Furthermore, it also includes an evaporator crystallizer, which is connected to the liquid phase outlet of the second precipitation filter press.

[0015] Furthermore, the flow rate of the first branch accounts for 60% to 80% of the output flow rate of the first sedimentation filter press. Attached Figure Description

[0016] The accompanying drawings are provided to further understand this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0017] Figure 1 This is a schematic diagram of the structure of a magnesium sulfate wastewater treatment system provided in one embodiment of this application.

[0018] Label Explanation: 10. Raw water tank; 11. First working pump; 20. Degravimetric device; 21. Degravimetric reaction mechanism; 22. Degravimetric filter press; 23. Degravimetric transfer pump; 31. Alkaline precipitation mechanism; 32. First precipitation filter press; 33. Second working pump; 40. Acidic precipitation device; 41. pH adjustment mechanism; 42. Acidic precipitation mechanism; 43. Second precipitation filter press; 44. Third working pump; 45. Fourth working pump; 51. First branch; 52. Second branch. Detailed Implementation

[0019] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0020] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0022] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0024] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0025] like Figure 1As shown, one embodiment of this application provides a magnesium sulfate wastewater treatment system, including a raw water tank 10, a gravimetric dewatering device 20, an alkaline precipitation mechanism 31, a first precipitation filter press 32, and an acidic precipitation device 40 arranged sequentially. The raw water tank 10 stores magnesium sulfate wastewater, which originates from the rare earth smelting process and contains metallic impurities such as calcium, nickel, iron, and cobalt. The gravimetric dewatering device 20 is used to degraviate the magnesium sulfate wastewater to remove metallic impurities such as calcium, nickel, iron, and cobalt. Of course, the gravimetric dewatering device 20 typically cannot completely remove metallic impurities; it only reduces the content of metallic impurities in the wastewater to avoid affecting the subsequent wastewater treatment effect, thus ensuring a more stable subsequent wastewater treatment effect.

[0026] The alkaline precipitation unit 31 is connected to the liquid phase outlet of the gravimetric dewatering device 20 and is used to perform alkaline precipitation on the wastewater after gravimetric dewatering. This involves adding ammonia to the wastewater to react with magnesium sulfate and form magnesium hydroxide precipitate. Simultaneously, residual metal impurities in the wastewater are further precipitated and removed. The first precipitation filter press 32 filters out the precipitate, and the filtered wastewater can then enter the acidic precipitation unit 40. The acidic precipitation unit 40 performs acidic precipitation on the wastewater by adding oxalic acid to form magnesium oxalate precipitate, further removing magnesium and other metal impurities from the wastewater. The acidic precipitation unit 40 can also separate the precipitate from the liquid. The separated liquid contains a large amount of ammonium sulfate, which can be used in agricultural compound fertilizers.

[0027] It should be explained that for existing membrane separation methods, the product is magnesium sulfate concentrate, so its treatment effect is related to the metal impurity content in the magnesium sulfate concentrate. For wastewater containing a large amount of other metal ions (such as calcium, nickel, iron, and cobalt mentioned above), these metal ions will enter the magnesium sulfate concentrate, resulting in poor treatment effect for the magnesium sulfate wastewater. The magnesium sulfate wastewater treatment system in the above embodiments uses a different treatment method to treat magnesium sulfate wastewater, and the product is ammonium sulfate (other precipitates can also be used for other purposes depending on the situation). Therefore, the treatment effect of this application is related to the metal content in the ammonium sulfate.

[0028] It should be noted that the aforementioned magnesium sulfate wastewater treatment system removes most of the metal impurities through the gravimetric analyzer 20, and then sequentially removes the metal impurities from the wastewater through the alkaline precipitation unit 31 and the acidic precipitation unit 40. In the alkaline precipitation unit 31, ammonia is added to form ammonium sulfate. After separating the precipitate and the liquid, it is ensured that the liquid contains a large amount of ammonium sulfate with extremely low metal ion content. Furthermore, this magnesium sulfate treatment system removes metal ions through reaction precipitation, which, compared to membrane separation, eliminates the need to consider the mixing of magnesium ions with other metal ions, thus ensuring that the metal ion content in the ammonium sulfate product is within the acceptable error range. Therefore, it can be concluded that this magnesium sulfate wastewater treatment system can treat magnesium sulfate wastewater and guarantee stable treatment results.

[0029] Furthermore, the magnesium sulfate wastewater treatment system also includes a diversion mechanism. The input end of the diversion mechanism is connected to the liquid phase outlet of the first sedimentation filter press 32, and the output end of the diversion mechanism is divided into a first branch 51 and a second branch 52. The first branch 51 is connected to the alkaline precipitation reaction mechanism to transport the filtered wastewater back to the alkaline precipitation mechanism 31 to improve the removal efficiency of metal ions.

[0030] The magnesium sulfate wastewater treatment system described above removes most of the metal impurities through the gravimetric analyzer 20. Then, the wastewater is sequentially treated by an alkaline precipitation unit 31 and an acidic precipitation unit 40 to further remove metal impurities. In the alkaline precipitation unit 31, ammonia is added to form ammonium sulfate. After separating the precipitate and liquid, the system ensures that the liquid contains a large amount of ammonium sulfate with extremely low metal ion content, thus achieving stable treatment results while treating the magnesium sulfate wastewater. Furthermore, the diversion mechanism effectively improves the removal efficiency of metal ions.

[0031] In one embodiment, the magnesium sulfate wastewater treatment system further includes a first working pump 11, which is disposed between the raw water tank 10 and the decay device 20, for transporting the wastewater in the raw water tank 10 to the decay device 20.

[0032] In one embodiment, the degravation device 20 includes a degravation reaction mechanism 21 and a degravation filter press 22 sequentially disposed downstream of the raw water tank 10. The degravation reaction mechanism 21 is used to precipitate metal impurities in the wastewater to form metal precipitates in the wastewater, and the degravation filter press 22 is used to filter out the metal precipitates. An alkaline precipitation mechanism 31 is connected to the liquid phase outlet of the degravation filter press 22. Specifically, in the degravation reaction mechanism 21, a magnesium oxide suspension is added to the wastewater, and the pH is adjusted to 6.5 by continuous stirring to precipitate calcium, nickel, iron, and cobalt in the wastewater. The reaction liquid is then transported to the degravation filter press 22 to remove the precipitates, and the filtered wastewater is then transported to the alkaline precipitation mechanism 31. It should be noted that the metal precipitates filtered by the degravation filter press 22 can also be collected and further refined to separate metals such as nickel and cobalt, which is not limited here.

[0033] In practical applications, the degravation reaction mechanism 21 includes a degravation reaction vessel and a reactant supply module. Both the first working pump 11 and the reactant supply module are connected to the degravation reaction vessel. The first working pump 11 pumps wastewater from the raw water tank 10 into the degravation reaction vessel. The reactant supply module adds the aforementioned magnesium oxide suspension to the degravation reaction vessel. The concentration of the magnesium oxide suspension is 5%-10%. In the degravation reaction mechanism 21, the stirring speed is 300-400 rpm, the reaction time is 60-120 minutes, and the pH of the wastewater needs to be adjusted to 6.5-7.

[0034] In one embodiment, the degravation device 20 further includes a degravation transfer pump 23, which is disposed between the degravation reactor and the degravation filter press 22 to transfer the reacted liquid in the degravation reactor to the degravation filter press 22.

[0035] In one embodiment, the alkaline precipitation mechanism 31 includes an alkaline reaction vessel and an alkali supply module. The alkaline reaction vessel is connected to the liquid phase outlet of the gravimetric dewatering device 20, i.e., to the liquid phase outlet of the gravimetric filter press 22, to receive the filtered wastewater. The alkali supply module is connected to the alkaline reaction vessel and is used to input ammonia water into the alkaline reaction vessel for alkaline precipitation of the wastewater within the vessel. Simultaneously, it is determined that the first branch 51 is connected to the alkaline reaction vessel to return the wastewater to the vessel for further reaction, thereby improving the metal removal rate. The concentration of ammonia water is 20%-25%, the stirring speed within the alkaline reaction vessel is 200-300 rpm, the reaction time is 30-60 min, and the pH is 9-10. It should be explained that after the ammonia is added, magnesium hydroxide precipitate will form in the wastewater, and residual metal impurities can also precipitate, thereby further removing the metal impurities. At the same time, it can be determined that the magnesium hydroxide solid filtered out by the first sedimentation filter press 32 is crude.

[0036] In one embodiment, the magnesium sulfate wastewater treatment system further includes a second working pump 33, which is disposed between the alkaline precipitation mechanism 31 and the first precipitation filter press 32, and is used to pump the wastewater in the alkaline precipitation mechanism 31 to the first precipitation filter press 32. Specifically, the second working pump 33 is connected to the alkaline reaction vessel.

[0037] In one embodiment, in the flow distribution mechanism, the flow rate of the first branch 51 accounts for 60%-80% of the output flow rate of the first sedimentation filter press 32, and the corresponding flow rate of the second branch 52 accounts for 20%-40% of the output flow rate of the first sedimentation filter press 32. For example, the flow rate of the first branch 51 can account for 60% and the flow rate of the second branch 52 can account for 40%; the flow rate of the first branch 51 can account for 70% and the flow rate of the second branch 52 can account for 30%; the flow rate of the first branch 51 can account for 80% and the flow rate of the second branch 52 can account for 20%.

[0038] In one embodiment, the acid precipitation device 40 includes a pH adjustment mechanism 41 and an acid precipitation mechanism 42 sequentially disposed downstream of the diversion mechanism. The pH adjustment mechanism 41 is connected to the second branch 52 and is used to adjust the pH of the wastewater. After the pH is adjusted, the wastewater enters the acid precipitation mechanism 42, and then the acid precipitation mechanism 42 performs acid precipitation on the pH-adjusted wastewater to further remove metals from the wastewater and form ammonium sulfate product.

[0039] The pH adjustment mechanism 41 includes a pH adjustment tank and a first acid supply module. Both the second branch 52 and the first acid supply module are connected to the pH adjustment tank. The first acid supply module is used to input dilute sulfuric acid into the pH adjustment tank to adjust the pH of the wastewater to 7-8. Specifically, the concentration of the dilute sulfuric acid input into the pH adjustment tank by the first acid supply module is 5%-20%.

[0040] The acid precipitation mechanism 42 includes an acidic reactor and a second acid supply module. Both the pH adjustment mechanism 41 and the second acid supply module are connected to the acidic reactor. The second acid supply module is used to introduce oxalic acid into the acidic reactor to remove metals from the wastewater as much as possible. The concentration of oxalic acid is 10%, and the amount added is 1.1-1.2 times the magnesium content in the wastewater, calculated by molar ratio. It should be noted that the metal content in the wastewater can be obtained through sampling and testing. Oxalic acid is added based on the test results to ensure that metals, such as magnesium, are removed as much as possible, thereby improving the purity of the ammonium sulfate product.

[0041] In one embodiment, the acid precipitation device 40 further includes a second precipitation filter press 43, which is located downstream of the acid precipitation device 42 and is used to filter out the precipitate. The filtrate is a solution containing ammonium sulfate, and the metal content in the filtrate is extremely low. Further, the magnesium sulfate wastewater treatment system also includes an evaporator crystallizer connected to the liquid phase outlet of the second precipitation filter press 43, used to evaporate and crystallize the filtrate to generate ammonium sulfate product, which can be used in agricultural compound fertilizers.

[0042] In one embodiment, the acid precipitation apparatus 40 further includes a third working pump 44 and a fourth working pump 45. The third working pump 44 is disposed between the pH adjustment mechanism 41 and the acid precipitation mechanism 42, and is used to transport the pH-adjusted wastewater to the acid precipitation mechanism 42; the fourth working pump 45 is disposed between the acid precipitation mechanism 42 and the second precipitation filter press 43, and is used to transport the wastewater in the acid precipitation mechanism 42 to the second precipitation filter press 43. Specifically, the third working pump 44 is connected to the pH adjustment tank and the acid reaction vessel, and the fourth working pump 45 is connected to the acid reaction vessel and the second precipitation filter press 43.

[0043] To facilitate understanding of the technical solution of this application, the process flow of the above-mentioned magnesium sulfate wastewater treatment system is described herein with reference to a specific embodiment: The first working pump 11 pumps the wastewater (raw water) from the raw water tank 10 into the degravation reactor. A 5% magnesium oxide suspension is added to the reactor to adjust the pH to 6.5, while the mixture is stirred at 350 rpm for 120 minutes. Next, the degravation transfer pump 23 transports the wastewater from the reactor to the degravation filter press 22. The filter press separates the precipitate from the first filtrate, which is a refined magnesium sulfate solution. This first filtrate then enters the downstream alkaline reactor.

[0044] In the alkaline reaction vessel, the pH is adjusted to 9.5 by adding 20%-25% ammonia solution, and then stirred at 200 rpm for 60 minutes. Next, the second working pump 33 transports the wastewater from the alkaline reaction vessel to the first sedimentation filter press 32, where the precipitate and the second filtrate are separated. The precipitate is mainly magnesium hydroxide, and the second filtrate contains ammonium sulfate, magnesium sulfate, and ammonia solution.

[0045] The second filtrate is split by a diversion mechanism. 80% of the second filtrate is returned to the alkaline reactor for further reaction, while 20% enters the pH adjustment tank. The pH is adjusted to 7-8 by adding 10% dilute sulfuric acid. Next, the third working pump 44 transports the pH-adjusted second filtrate to the acidic reactor. In the acidic reactor, 10% oxalic acid is added at a molar ratio of 1.1 times the magnesium content, and the mixture is continuously stirred to precipitate magnesium oxalate. Next, the wastewater from the alkaline reactor is transported to the second precipitation filter press 43 by the fourth working pump 45. The second precipitation filter press 43 separates the precipitate from the third filtrate, which is a purified ammonium sulfate solution. Finally, the purified ammonium sulfate solution can be transported to an evaporator crystallizer to prepare high-purity ammonium sulfate.

[0046] It should be noted that the filter press mentioned above can be a plate and frame filter press or a diaphragm filter press. A plate and frame filter press is preferred, and the filtration pore size is 0.1 μm. Furthermore, referring to Table 1, it can be confirmed that the above-mentioned magnesium sulfate wastewater treatment system can effectively remove metals from the wastewater.

[0047] Table 1. Water quality of raw water and various filtrates In summary, the magnesium sulfate wastewater treatment system provided in this application has at least the following advantages: 1. It can treat magnesium sulfate wastewater and produce magnesium hydroxide and ammonium sulfate. Magnesium hydroxide can be used as an inorganic flame retardant, and ammonium sulfate can be used as an agricultural compound fertilizer. 2. In the heavy removal device 20, the pH of magnesium sulfate wastewater is adjusted by adding magnesium oxide. Then, based on the difference in solubility product, the metal impurities in the wastewater are precipitated as hydroxides, thereby achieving the removal and purification of wastewater without introducing other metal impurities. 3. In the acid precipitation device 40, oxalic acid is added to generate magnesium oxalate precipitate. At the same time, it can react with metals such as calcium in the wastewater to generate calcium oxalate precipitate, which further improves the metal removal rate and thus improves the purity of the ammonium sulfate product.

[0048] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A magnesium sulfate wastewater treatment system, characterized in that, include: Raw water tank; A gravimetric device is installed downstream of the raw water tank to remove metal impurities from the wastewater. An alkaline precipitation mechanism is located downstream of the gravimetric dewatering device and connected to the liquid phase outlet of the gravimetric dewatering device, and is used for alkaline precipitation of wastewater. The first precipitation filter press is located downstream of the alkaline precipitation mechanism; An acid precipitation device is installed downstream of the first precipitation filter press and is used to perform acid precipitation on wastewater. The flow splitting mechanism has an input end connected to the liquid phase outlet of the first precipitation filter press, and an output end divided into a first branch and a second branch. The first branch is connected to the alkaline precipitation reaction mechanism, and the second branch is connected to the acidic precipitation device. The flow rate of the first branch is greater than that of the second branch.

2. The magnesium sulfate wastewater treatment system according to claim 1, characterized in that, The degravity removal device includes a degravity removal reaction mechanism and a degravity removal filter press arranged sequentially downstream of the raw water tank. The degravity removal reaction mechanism is used to precipitate metal impurities in the wastewater, and the alkaline precipitation mechanism is connected to the liquid phase outlet of the degravity removal filter press.

3. The magnesium sulfate wastewater treatment system according to claim 2, characterized in that, The degravity removal device also includes a degravity removal conveying pump, which is located between the degravity removal reaction mechanism and the degravity removal filter press.

4. The magnesium sulfate wastewater treatment system according to claim 1, characterized in that, The alkaline precipitation mechanism includes an alkaline reaction vessel and an alkali supply module. The alkaline reaction vessel is connected to the liquid phase outlet of the degravation device, and the alkali supply module is connected to the alkaline reaction vessel for feeding ammonia water into the alkaline reaction vessel. The first branch is connected to the alkaline reaction vessel.

5. The magnesium sulfate wastewater treatment system according to claim 1, characterized in that, The acid precipitation device includes a pH adjustment mechanism and an acid precipitation mechanism sequentially disposed downstream of the diversion mechanism. The pH adjustment mechanism is connected to the second branch and is used to adjust the pH of the wastewater. The acid precipitation mechanism is used to perform acid precipitation on the pH-adjusted wastewater.

6. The magnesium sulfate wastewater treatment system according to claim 5, characterized in that, The pH adjustment mechanism includes a pH adjustment tank and a first acid supply module. The second branch and the first acid supply module are both connected to the pH adjustment tank. The first acid supply module is used to input dilute sulfuric acid into the pH adjustment tank. The acid precipitation mechanism is connected to the pH adjustment tank.

7. The magnesium sulfate wastewater treatment system according to claim 5, characterized in that, The acid precipitation mechanism includes an acid reaction vessel and a second acid supply module. Both the pH adjustment mechanism and the second acid supply module are connected to the acid reaction vessel. The second acid supply module is used to input oxalic acid into the acid reaction vessel.

8. The magnesium sulfate wastewater treatment system according to claim 5, characterized in that, The acid precipitation apparatus further includes a second precipitation filter press, which is located downstream of the acid precipitation mechanism.

9. The magnesium sulfate wastewater treatment system according to claim 8, characterized in that, It also includes an evaporator crystallizer, which is connected to the liquid phase outlet of the second precipitation filter press.

10. The magnesium sulfate wastewater treatment system according to claim 1, characterized in that, The flow rate of the first branch accounts for 60% to 80% of the output flow rate of the first sedimentation filter press.

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