A system for treating nickel sulfate extraction raffinate

Abstract

The utility model provides a kind of nickel sulfate extraction after waste liquid treatment system, including sulphate waste liquid treatment device, chlorate waste liquid treatment device, copper chloride manganese liquid treatment device and mixed processing device, sulphate waste liquid treatment device includes sulphate wastewater tank, oxidation treatment unit, sulphate wastewater filter pressing unit, boron precipitation treatment unit and boron precipitation filter pressing unit;Chlorate waste liquid treatment device includes chlorate mixing unit and chlorate neutralization unit;Copper chloride manganese liquid treatment device includes replacement unit and filter pressing unit, and filter pressing unit is connected with replacement unit, and mixed processing device includes neutralization mixing unit and mixed filter pressing unit;In the utility model, sulphate waste liquid, chlorate waste liquid, copper chloride manganese liquid in nickel sulfate extraction after waste liquid are first separated and handled, then mixed processing is carried out, manganese and nickel-containing impurities in waste liquid can be recycled, the utilization rate of material is improved, and material waste is avoided.

Description

Technical Field

[0001] This utility model relates to the field of waste liquid treatment technology, and in particular to a waste liquid treatment system after nickel sulfate extraction. Background Technology

[0002] The waste liquid from nickel sulfate extraction contains large amounts of sulfates and chlorides. Untreated waste liquid will have a significant impact on the environment. Sulfates accelerate the formation of methylmercury in water bodies. Methylmercury is a highly toxic organometallic compound; its formation in water bodies poses a great threat to the surrounding ecosystem and the growth of flora and fauna. Sulfates alter the original ecological regulatory functions of water bodies, leading to the death and extinction of various organisms, and causing the water body to lose its ecological regulatory functions.

[0003] The existing treatment method generally involves first using chemical precipitation to add chemical reagents to cause heavy metal ions to form insoluble compounds and precipitate, thus initially reducing the content of heavy metal ions, and then using membrane technology to further purify the water.

[0004] The existing technologies have the following problems: they all involve mixing the waste liquid after nickel sulfate extraction together for treatment, resulting in low treatment efficiency. Utility Model Content

[0005] In view of this, it is necessary to provide a waste liquid treatment system after nickel sulfate extraction that can solve the above problems.

[0006] This utility model provides a waste liquid treatment system after nickel sulfate extraction, comprising: A sulfate wastewater treatment device includes a sulfate wastewater tank, an oxidation treatment unit, a sulfate wastewater pressure filtration unit, a boron precipitation treatment unit, and a boron precipitation pressure filtration unit. The oxidation treatment unit is connected to the sulfate wastewater tank and is used to oxidize the sulfate wastewater in the sulfate wastewater tank. The sulfate wastewater pressure filtration unit is connected to the oxidation treatment unit and is used to filter the oxidized sulfate wastewater. The boron precipitation treatment unit neutralizes the filtrate formed by pressure filtration. The boron precipitation pressure filtration unit is connected to the boron precipitation treatment unit and is used to filter the neutralized liquid. A chloride wastewater treatment device includes a chloride mixing unit and a chloride neutralization unit. The chloride mixing unit is used to mix chloride wastewater and nickel electrolytic wastewater. The chloride neutralization unit is connected to the chloride mixing unit and is used to neutralize the mixture in the chloride mixing unit. A copper-manganese chloride solution treatment device includes a displacement unit and a pressure filtration unit. The displacement unit is used to displace the copper-manganese chloride solution, and the pressure filtration unit is connected to the displacement unit and is used to filter the displaced solution. The system also includes a mixing and processing device, comprising a neutralization and mixing unit and a mixing and filtration unit. The neutralization and mixing unit is connected to the boron precipitation filtration unit, the chloride neutralization unit, and the filtration unit to mix and neutralize the liquid. The mixing and filtration unit is connected to the neutralization and mixing unit and is used to filter the mixed and neutralized solution.

[0007] In other embodiments, the oxidation treatment unit includes an oxidation tank, which has an inlet connected to the sulfate wastewater tank, an outlet connected to the sulfate wastewater pressure filtration unit, a first feed port for adding acid, a second feed port for adding hydrogen peroxide, and a third feed port for adding activated carbon.

[0008] In other embodiments, the boron precipitation treatment unit includes multiple boron precipitation tanks and stirring assemblies corresponding to each boron precipitation tank. The top of each boron precipitation tank is provided with an alkali inlet and a steam inlet, and the bottom of each boron precipitation tank is provided with a waste liquid outlet that communicates with the boron precipitation filter press unit.

[0009] In other embodiments, the chloride mixing unit includes a chloride mixing tank and a mixing and stirring assembly. The chloride mixing tank has a chloride inlet and an electrolytic nickel wastewater inlet. The mixing and stirring assembly is fixed on the chloride mixing tank and the stirring end of the mixing and stirring assembly extends into the chloride mixing tank. The chloride mixing tank has a mixed liquid outlet connected to the chloride neutralization unit.

[0010] In other embodiments, the chloride neutralization unit includes a neutralization tank and a pH detection device. The neutralization tank has a mixed liquid inlet communicating with the chloride mixing unit and a neutralization liquid addition port for adding neutralizing liquid. The pH detection device is embedded in the inner wall of the neutralization tank and is used to detect the pH value inside the neutralization tank.

[0011] In other embodiments, the replacement unit includes a copper-iron replacement tank and a replacement stirring assembly. The copper-iron replacement tank has a copper chloride inlet and an iron powder inlet. The replacement stirring assembly is fixed on the copper-iron replacement tank, and the stirring end of the replacement stirring assembly extends into the copper-iron replacement tank.

[0012] In other embodiments, the neutralization mixing unit includes a neutralization mixing tank and a neutralization stirring assembly. The neutralization mixing tank has a first waste liquid inlet communicating with the boron precipitation filter press unit, a second waste liquid inlet communicating with the chloride neutralization unit, a third waste liquid inlet communicating with the filter press unit, and an alkali addition port for adding alkali solution. The neutralization stirring assembly is fixed on the neutralization mixing tank, and the stirring end of the neutralization stirring assembly extends into the neutralization mixing tank. A pH meter is embedded in the inner wall of the neutralization mixing tank.

[0013] In other embodiments, the sulfate waste liquid treatment device further includes a sulfate wastewater heat exchanger, one end of which is connected to the sulfate wastewater tank and the other end of which is connected to the oxidation treatment unit. The sulfate wastewater heat exchanger is provided with a steam inlet.

[0014] In other embodiments, the sulfate wastewater pressure filtration unit includes a first filter press, the inlet of which is connected to the oxidation treatment unit, and the outlet of which is connected to the boron precipitation treatment unit.

[0015] In other embodiments, the boron precipitation filter press unit includes a second filter press, the inlet of which is connected to the boron precipitation treatment unit, and the outlet of which is connected to the boron precipitation treatment unit.

[0016] The beneficial effects of this utility model are as follows: This utility model includes a sulfate wastewater treatment device, a chloride wastewater treatment device, a copper-manganese chloride solution treatment device, and a mixing treatment device. The sulfate wastewater treatment device includes a sulfate wastewater tank, an oxidation treatment unit, a sulfate wastewater pressure filtration unit, a boron precipitation treatment unit, and a boron precipitation pressure filtration unit. The oxidation treatment unit is connected to the sulfate wastewater tank, the sulfate wastewater pressure filtration unit is connected to the oxidation treatment unit, and the boron precipitation pressure filtration unit is connected to the boron precipitation treatment unit. The chloride wastewater treatment device includes a chloride mixing unit and a chloride neutralization unit. The copper-manganese chloride solution treatment device includes a displacement unit and a pressure filtration unit. The filter press unit is connected to the replacement unit. The mixing treatment device includes a neutralization mixing unit and a mixing filter press unit. The neutralization mixing unit is connected to the boron precipitation filter press unit, the chloride neutralization unit, and the filter press unit. The mixing filter press unit is connected to the neutralization mixing unit. In this invention, the sulfate waste liquid, chloride waste liquid, and copper-manganese chloride liquid in the nickel sulfate extraction waste liquid are first treated separately, and then mixed. This can recover manganese and nickel-containing impurities in the waste liquid, and part of it can be recycled back to the nickel sulfate preparation process system for nickel sulfate preparation, thereby improving the utilization rate of materials and avoiding material waste. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the module of the nickel sulfate extraction waste liquid treatment system of this utility model; Figure 2 for Figure 1 Schematic diagram of the intermediate boron precipitation treatment unit; Among them: 1-sulfate waste liquid treatment device, 11-sulfate wastewater tank, 12-oxidation treatment unit, 13-sulfate wastewater pressure filter unit, 14-boron precipitation treatment unit, 141-boron precipitation tank, 142-stirring assembly, 15-boron precipitation pressure filter unit, 16-sulfate wastewater heat exchanger. 2-Chloride waste liquid treatment device, 21-chloride mixing unit, 211-chloride mixing tank, 212-mixing and stirring assembly, 22-chloride neutralization unit, 221-neutralization tank; 3-Copper chloride manganese solution treatment device, 31-displacement unit, 311-copper-iron displacement tank, 312-displacement stirring assembly, 32-filter press unit. 4-Mixing treatment device, 41-Neutralization mixing unit, 411-Mixing tank, 412-Neutralization stirring assembly, 42-Mixing and filtration unit. Detailed Implementation

[0019] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0020] like Figure 1-2As shown, an embodiment of this utility model provides a waste liquid treatment system for nickel sulfate extraction, comprising: a sulfate waste liquid treatment device 1, a chloride waste liquid treatment device 2, a copper-manganese chloride solution treatment device 3, and a mixing treatment device 4. The sulfate waste liquid treatment device 1 includes a sulfate wastewater tank 11, an oxidation treatment unit 12, a sulfate wastewater pressure filtration unit 13, a boron precipitation treatment unit 14, and a boron precipitation pressure filtration unit 15. The oxidation treatment unit 12 is connected to the sulfate wastewater tank 11 and is used to oxidize the sulfate waste liquid in the sulfate wastewater tank 11. The sulfate wastewater pressure filtration unit 13 is connected to the oxidation treatment unit 12 and is used to filter the oxidized sulfate wastewater. The boron precipitation treatment unit 14 neutralizes the filtrate formed by pressure filtration. The boron precipitation pressure filtration unit 15 is connected to the boron precipitation treatment unit 14 and is used to filter the neutralized liquid. The chloride waste liquid treatment device... The device 2 includes a chloride mixing unit 21 and a chloride neutralization unit 22. The chloride mixing unit 21 is used to mix chloride waste liquid and electrolytic nickel wastewater. The chloride neutralization unit 22 is connected to the chloride mixing unit 21 and is used to neutralize the mixture in the chloride mixing unit 21. The copper chloride manganese liquid treatment device 3 includes a displacement unit 31 and a pressure filter unit 32. The displacement unit 31 is used to displace the copper chloride manganese liquid. The pressure filter unit 32 is connected to the displacement unit 31 and is used to filter the displaced solution. The mixing treatment device 4 includes a neutralization mixing unit 41 and a mixing pressure filter unit 42. The neutralization mixing unit 41 is connected to the boron precipitation pressure filter unit 15, the chloride neutralization unit 22, and the pressure filter unit 32 to mix and neutralize the liquid. The mixing pressure filter unit 42 is connected to the neutralization mixing unit 41 and is used to filter the mixed and neutralized solution.

[0021] In this invention, the sulfate waste liquid, chloride waste liquid, and copper-manganese chloride solution in the nickel sulfate extraction waste liquid are first treated separately and then mixed. This process can recover manganese and nickel-containing impurities from the waste liquid, and part of it can be recycled back to the nickel sulfate preparation process system for nickel sulfate preparation, thereby improving the utilization rate of materials and avoiding material waste.

[0022] Furthermore, the sulfate wastewater tank 11 is used to collect sulfate wastewater, and the sulfate wastewater tank 11 is provided with an outlet pipe that is connected to the oxidation treatment unit 12.

[0023] Furthermore, the oxidation treatment unit 12 includes an oxidation tank, which has an inlet connected to the sulfate wastewater tank 11, an outlet connected to the sulfate wastewater pressure filtration unit 13, a first feed port for adding acid, a second feed port for adding hydrogen peroxide, and a third feed port for adding activated carbon. In use, the acid promotes the oxidation reaction of organic pollutants, converting them into substances more easily adsorbed by activated carbon. The added hydrogen peroxide acts as a catalyst, activating the adsorbed substances on the activated carbon.

[0024] Furthermore, the sulfate wastewater pressure filtration unit 13 includes a first filter press, the inlet of which is connected to the oxidation treatment unit 12, and the outlet of which is connected to the boron precipitation treatment unit 14. The wastewater after pressure filtration is discharged to the boron precipitation treatment unit 14, and the solid residue after pressure filtration mainly includes activated carbon adsorbed with oxidizing substances, which can be recycled.

[0025] The filter press is a conventional piece of equipment in the art and is well known to those skilled in the art, so it will not be described in detail here.

[0026] Furthermore, the boron precipitation treatment unit 14 includes multiple boron precipitation tanks 141 and stirring components 142 corresponding to each boron precipitation tank 141. Each boron precipitation tank 141 has an alkali inlet and a steam inlet at its top, and a waste liquid outlet at its bottom that communicates with the boron precipitation filter press unit 15. The boron precipitation tank 141 is filled with 32% alkali solution and 0.4 MPa steam through the alkali inlet and the steam inlet, respectively. After boron precipitation, the waste liquid is discharged to the boron precipitation filter press unit 15 through the waste liquid outlet.

[0027] Furthermore, the boron precipitation filter press unit 15 includes a second filter press, the inlet of which is connected to the boron precipitation treatment unit 14, and the outlet of which is connected to the boron precipitation treatment unit 14. The waste liquid after filtration is discharged to the mixing treatment device 4.

[0028] Specifically, the chloride mixing unit 21 includes a chloride mixing tank 211 and a mixing and stirring assembly 212. The chloride mixing tank 211 has a chloride inlet and a nickel electrolytic wastewater inlet. The mixing and stirring assembly 212 is fixed to the chloride mixing tank 211, and the stirring end of the mixing and stirring assembly 212 extends into the chloride mixing tank 211. The chloride mixing tank 211 has a mixed liquid outlet connected to the chloride neutralization unit 22. The chloride wastewater and nickel electrolytic wastewater are sent to the chloride mixing tank, mixed evenly, and then sent to the chloride neutralization unit 22.

[0029] Furthermore, the chloride neutralization unit 22 includes a neutralization tank 221 and a pH detection device. The neutralization tank 221 has a mixed liquid inlet communicating with the chloride mixing unit 21 and a neutralization liquid addition port for adding neutralizing liquid. The pH detection device is embedded in the inner wall of the neutralization tank 221 and is used to detect the pH value inside the neutralization tank 221.

[0030] Specifically, the replacement unit 31 includes a copper-iron replacement tank 311 and a replacement stirring assembly 312. The copper-iron replacement tank 311 has a copper chloride inlet and an iron powder inlet. The replacement stirring assembly 312 is fixed to the copper-iron replacement tank 311, and the stirring end of the replacement stirring assembly 312 extends into the copper-iron replacement tank 311. Copper-manganese liquid is sent into the copper-iron replacement tank 311, and iron powder is added through the iron powder inlet to replace the copper, forming ferrous chloride.

[0031] The most reasonable and simplest method for recovering copper from waste liquid is to use scrap iron for displacement precipitation, producing metallic copper deposits suitable for metallurgy. Based on standard electrode potentials: Cu 2+ +2e=CuE0=+0.34V(1) Fe 2+ +2e=FeE0=-0.44V(2) Copper ions are readily reduced on iron surfaces, simultaneously dissolving a relative amount of iron. Under standard conditions, the reaction is as follows: CuCl2 + Fe → FeCl2 + Cu (3) Spongy metallic copper can be recovered using the displacement precipitation method for refining pure copper. On the other hand, replacing heavy metals with a more positive potential than Fe in the wastewater with iron makes wastewater discharge safer. After neutralization and hydrolysis, the copper-removed wastewater yields a residue containing ferric hydroxide, which, after drying, can be used as a colorant in building materials. During the copper / iron displacement process, the iron powder and solution are vigorously stirred together to maximize contact between the wastewater and the iron powder surface, resulting in a good displacement effect.

[0032] Furthermore, the filter press unit 32 includes a third filter press, the inlet of which is connected to the replacement unit 31, and the outlet of which is connected to the mixing and treatment device 4. The third filter press filters the ferrous chloride solution, and the filtrate flows into the mixing and treatment device 4. The solid residue after filtration contains manganese and copper, which can be recycled.

[0033] Furthermore, the neutralization mixing unit 41 includes a neutralization mixing tank 411 and a neutralization stirring assembly 412. The neutralization mixing tank 411 has a first waste liquid inlet connected to the boron precipitation filter press unit 15, a second waste liquid inlet connected to the chloride neutralization unit 22, a third waste liquid inlet connected to the filter press unit 32, and an alkali inlet for adding alkali. The neutralization stirring assembly 412 is fixed to the neutralization mixing tank 411, and its stirring end extends into the neutralization mixing tank 411. A pH meter is embedded in the inner wall of the neutralization mixing tank 411. In use, alkali is added to the neutralization mixing tank 411 through the alkali inlet, and the neutralization stirring assembly 412 stirs the liquid in the neutralization mixing tank 411. When the pH in the neutralization mixing tank 411 reaches 11-12, it is sent to the mixing filter press unit 42 for filtration.

[0034] Specifically, the mixing and filtration unit 42 includes a fourth filter press, the inlet of which is connected to the neutralization and mixing unit 41. The fourth filter press filters the mixture formed by the neutralization and mixing unit 41, and the solid residue after filtration contains manganese, which can be recycled.

[0035] Furthermore, the sulfate wastewater treatment device 1 also includes a sulfate wastewater heat exchanger 16. One end of the sulfate wastewater heat exchanger is connected to the sulfate wastewater tank 11, and the other end is connected to the oxidation treatment unit 12. The sulfate wastewater heat exchanger is equipped with a steam inlet. In use, steam is introduced through the steam inlet, and after exchanging heat with the sulfate wastewater, the temperature of the sulfate wastewater is raised to about 35°C. Raising the temperature can accelerate the subsequent reaction rate of the sulfate wastewater.

[0036] The beneficial effects of this utility model are: This utility model includes a sulfate wastewater treatment device, a chloride wastewater treatment device, a copper-manganese chloride solution treatment device, and a mixing treatment device. The sulfate wastewater treatment device includes a sulfate wastewater tank, an oxidation treatment unit, a sulfate wastewater pressure filtration unit, a boron precipitation treatment unit, and a boron precipitation pressure filtration unit. The oxidation treatment unit is connected to the sulfate wastewater tank, the sulfate wastewater pressure filtration unit is connected to the oxidation treatment unit, and the boron precipitation pressure filtration unit is connected to the boron precipitation treatment unit. The chloride wastewater treatment device includes a chloride mixing unit and a chloride neutralization unit. The copper-manganese chloride solution treatment device includes a displacement unit and a pressure filtration unit. The filter press unit is connected to the replacement unit. The mixing treatment device includes a neutralization mixing unit and a mixing filter press unit. The neutralization mixing unit is connected to the boron precipitation filter press unit, the chloride neutralization unit, and the filter press unit. The mixing filter press unit is connected to the neutralization mixing unit. In this invention, the sulfate waste liquid, chloride waste liquid, and copper-manganese chloride liquid in the nickel sulfate extraction waste liquid are first treated separately, and then mixed. This can recover manganese and nickel-containing impurities in the waste liquid, and part of it can be recycled back to the nickel sulfate preparation process system for nickel sulfate preparation, thereby improving the utilization rate of materials and avoiding material waste.

[0037] In the description of this application, it should be noted that the terms "upper" and "lower," 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 module 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. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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 between two components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0038] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0039] The specific embodiments of this utility model described above do not constitute a limitation on the scope of protection of this utility model. Any other corresponding changes and modifications made based on the technical concept of this utility model should be included within the scope of protection of the claims of this utility model.

Claims

1. A waste liquid treatment system after nickel sulfate extraction, characterized in that, include: A sulfate wastewater treatment device includes a sulfate wastewater tank, an oxidation treatment unit, a sulfate wastewater pressure filtration unit, a boron precipitation treatment unit, and a boron precipitation pressure filtration unit. The oxidation treatment unit is connected to the sulfate wastewater tank and is used to oxidize the sulfate wastewater in the sulfate wastewater tank. The sulfate wastewater pressure filtration unit is connected to the oxidation treatment unit and is used to filter the oxidized sulfate wastewater. The boron precipitation treatment unit neutralizes the filtrate formed by pressure filtration. The boron precipitation pressure filtration unit is connected to the boron precipitation treatment unit and is used to filter the neutralized liquid. A chloride wastewater treatment device includes a chloride mixing unit and a chloride neutralization unit. The chloride mixing unit is used to mix chloride wastewater and nickel electrolytic wastewater. The chloride neutralization unit is connected to the chloride mixing unit and is used to neutralize the mixture in the chloride mixing unit. A copper-manganese chloride solution treatment device includes a displacement unit and a pressure filtration unit. The displacement unit is used to displace the copper-manganese chloride solution, and the pressure filtration unit is connected to the displacement unit and is used to filter the displaced solution. The system also includes a mixing and processing device, comprising a neutralization and mixing unit and a mixing and filtration unit. The neutralization and mixing unit is connected to the boron precipitation filtration unit, the chloride neutralization unit, and the filtration unit to mix and neutralize the liquid. The mixing and filtration unit is connected to the neutralization and mixing unit and is used to filter the mixed and neutralized solution.

2. The nickel sulfate extraction waste liquid treatment system as described in claim 1, characterized in that, The oxidation treatment unit includes an oxidation tank, which has an inlet connected to the sulfate wastewater tank, an outlet connected to the sulfate wastewater pressure filtration unit, a first feed port for adding acid, a second feed port for adding hydrogen peroxide, and a third feed port for adding activated carbon.

3. The nickel sulfate extraction waste liquid treatment system as described in claim 1, characterized in that, The boron precipitation treatment unit includes multiple boron precipitation tanks and stirring components corresponding to each boron precipitation tank. The top of each boron precipitation tank is provided with an alkali inlet and a steam inlet, and the bottom of each boron precipitation tank is provided with a waste liquid outlet that is connected to the boron precipitation filter press unit.

4. The nickel sulfate extraction waste liquid treatment system as described in claim 1, characterized in that, The chloride salt mixing unit includes a chloride salt mixing tank and a mixing and stirring assembly. The chloride salt mixing tank has a chloride salt inlet and an electrolytic nickel wastewater inlet. The mixing and stirring assembly is fixed on the chloride salt mixing tank and the stirring end of the mixing and stirring assembly extends into the chloride salt mixing tank. The chloride salt mixing tank has a mixed liquid outlet connected to the chloride salt neutralization unit.

5. The nickel sulfate extraction waste liquid treatment system as described in claim 1, characterized in that, The chloride neutralization unit includes a neutralization tank and a pH detection device. The neutralization tank has a mixed liquid inlet that communicates with the chloride mixing unit and a neutralization liquid addition port for adding neutralizing liquid. The pH detection device is embedded in the inner wall of the neutralization tank and is used to detect the pH value inside the neutralization tank.

6. The nickel sulfate extraction waste liquid treatment system as described in claim 4, characterized in that, The replacement unit includes a copper-iron replacement tank and a replacement stirring assembly. The copper-iron replacement tank has a copper chloride inlet and an iron powder inlet. The replacement stirring assembly is fixed on the copper-iron replacement tank, and the stirring end of the replacement stirring assembly extends into the copper-iron replacement tank.

7. The nickel sulfate extraction waste liquid treatment system as described in claim 1, characterized in that, The neutralization mixing unit includes a neutralization mixing tank and a neutralization stirring assembly. The neutralization mixing tank has a first waste liquid inlet connected to the boron precipitation filter press unit, a second waste liquid inlet connected to the chloride neutralization unit, a third waste liquid inlet connected to the filter press unit, and an alkali addition port for adding alkali solution. The neutralization stirring assembly is fixed on the neutralization mixing tank, and the stirring end of the neutralization stirring assembly extends into the neutralization mixing tank. A pH meter is embedded in the inner wall of the neutralization mixing tank.

8. The nickel sulfate extraction waste liquid treatment system as described in claim 1, characterized in that, The sulfate waste liquid treatment device also includes a sulfate wastewater heat exchanger, one end of which is connected to the sulfate wastewater tank and the other end is connected to the oxidation treatment unit. The sulfate wastewater heat exchanger is provided with a steam inlet.

9. The nickel sulfate extraction waste liquid treatment system as described in claim 8, characterized in that, The sulfate wastewater pressure filtration unit includes a first filter press, the inlet of which is connected to the oxidation treatment unit, and the outlet of which is connected to the boron precipitation treatment unit.

10. The nickel sulfate extraction waste liquid treatment system as described in claim 1, characterized in that, The boron precipitation filter press unit includes a second filter press, the inlet of which is connected to the boron precipitation treatment unit, and the outlet of which is connected to the boron precipitation treatment unit.

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