Electroplating cyanide-containing wastewater treatment system
A new electroplating wastewater treatment system for cyanide-containing wastewater utilizes steps such as precipitation, acidification, crystallization, flocculation, and oxidation to solve the problems of high cost and low recovery rate in cyanide-containing wastewater treatment. This system achieves green and economical treatment with low reagent consumption and low energy consumption, and improves the recovery rate of valuable metals and the reuse rate of water resources.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2026-04-03
AI Technical Summary
Existing technologies for treating cyanide-containing wastewater suffer from high treatment costs, low recovery rates of valuable metals, a high risk of secondary pollution, and excessive energy consumption, making it difficult to achieve wastewater treatment with low reagent dosage and a green and economical approach.
The system employs a series of interconnected cyanide precipitation, acidification, crystallization and aging, primary flocculation and sedimentation, solid-liquid separation, primary cyanide oxidation, secondary cyanide oxidation, and secondary flocculation and sedimentation systems. Through precipitation, acidification, crystallization, flocculation, and oxidation, cyanide and valuable metals are removed from wastewater, achieving the recovery of valuable metals and the resource utilization of wastewater.
It achieves wastewater treatment with low reagent consumption and low energy consumption, thorough cyanide removal, rapid oxidation reaction, and easy recovery of valuable metals from sludge. The treated wastewater can be recycled, reducing the use of chemical oxidants and improving the recovery rate of valuable metals and the reuse rate of water resources.
Smart Images
Figure CN224077187U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of wastewater treatment technology, and in particular to a system for treating cyanide-containing wastewater from electroplating. Background Technology
[0002] Although cyanide plating is being replaced in the market, due to the superior performance of cyanide plating products, their position in high-precision fields such as aviation, aerospace, and integrated circuits is becoming more prominent and difficult to replace in the short term.
[0003] Cyanide-containing wastewater mainly originates from processes such as gold plating, silver plating, and copper plating. Due to the high concentration and toxicity of cyanide, cyanide-containing wastewater is a major concern for those involved in the electroplating process and its treatment. Since cyanide-containing wastewater not only contains highly toxic cyanide but also valuable metals and additives, it is currently primarily treated using the oxychlorination method, which suffers from high treatment costs and low recovery rates of valuable metals. Theoretically, electrolysis is superior to oxidation for treating cyanide-containing wastewater. Its advantages include: First, the free radicals generated during electrolysis react directly and indiscriminately with pollutants in the wastewater, oxidizing and destroying them, while the cathode reduces some heavy metals to elemental form for recovery; second, electrolysis can be used alone or in combination with other treatment methods; third, the electrolysis process does not introduce toxic substances and does not produce secondary pollution; fourth, electrolysis equipment and its operation are relatively simple, and with proper design, the equipment manufacturing and production costs are not high.
[0004] However, considering the excessive energy consumption of electrolysis and the tendency to generate ammonia nitrogen, which not only affects the compliance of wastewater discharge but also easily breeds microorganisms, chemical deoxidation treatment of cyanide-containing wastewater is too resource-intensive and introduces large amounts of salt, further burdening the water body. Therefore, developing a more rational and simpler electroplating cyanide-containing wastewater treatment system based on water conditions and operational requirements, achieving low reagent dosage, green economy, and valuable metal recovery, is a pressing issue that needs to be addressed. Utility Model Content
[0005] The purpose of this invention is to provide a cyanide-containing wastewater treatment system for electroplating, which solves the problems existing in the above-mentioned related technologies. It can reduce the consumption of chemical oxidants during wastewater treatment and facilitate the recovery of valuable metals. The process is simple and easy to operate.
[0006] To achieve the above objectives, this utility model provides the following solution:
[0007] This utility model provides a cyanide-containing wastewater treatment system for electroplating, comprising a cyanide precipitation system, an acidification system, a crystallization and aging system, a primary flocculation and sedimentation system, and a solid-liquid separation system connected in sequence. The inlet of the cyanide precipitation system is used to introduce cyanide-containing wastewater, and the system can add a precipitant to the wastewater to induce precipitation. The acidification system can add a first acidic substance to the precipitated cyanide-containing wastewater to induce acidification. The crystallization and aging system can add a first alkaline substance to the acidified cyanide-containing wastewater to induce crystallization and aging. The primary flocculation and sedimentation system can add a first flocculant to the crystallized and aged cyanide-containing wastewater to induce flocculation and sedimentation. The solid-liquid separation system can separate the flocculated and sedimented cyanide-containing wastewater into solid and liquid phases. The liquid phase outlet of the solid-liquid separation system is used to discharge filtrate, and the solid phase outlet is used to discharge primary flocculation and sedimentation sludge.
[0008] It also includes a primary cyanide oxidation system, a secondary cyanide oxidation system, and a secondary flocculation and sedimentation system connected in sequence. The liquid phase outlet of the solid-liquid separation system is connected to the inlet of the primary cyanide oxidation system. The primary cyanide oxidation system can add a second alkaline substance and a first oxidant to the filtrate to remove cyanide and organic matter. The secondary cyanide oxidation system can add a second acidic substance and a second oxidant to the filtrate after primary cyanide oxidation to remove ammonia nitrogen and complexed ions. The secondary flocculation and sedimentation system can add a second flocculant to the filtrate after secondary cyanide oxidation to induce flocculation and sedimentation. The liquid phase outlet of the secondary flocculation and sedimentation system is used to discharge the supernatant, and the solid phase outlet of the secondary flocculation and sedimentation system is used to discharge the secondary flocculated and settled sludge.
[0009] Preferably, the precipitant is an iron-containing solution; the cyanide precipitation system includes an iron-containing solution preparation device, an iron-containing solution dosing device, an iron-containing solution reaction device, and a precipitation reaction device connected in sequence.
[0010] Preferably, the first acidic substance is one or more of sulfuric acid, hydrochloric acid, and nitric acid; the acidification system includes an acid preparation device, an acid dosing device, and a closed mixing device for acidification connected in sequence.
[0011] Preferably, the first alkaline substance is one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide; the crystallization aging system includes an alkali preparation device, an alkali addition device, a closed mixing device for crystallization aging, and a cyanide tail gas absorption device for crystallization aging, which are connected in sequence.
[0012] Preferably, the first flocculant is one or more of polyferric sulfate, polyaluminum chloride, and polyacrylamide; the primary flocculation and sedimentation system includes a first flocculant preparation device, a first flocculant dosing device, a closed mixing device for primary flocculation and sedimentation, and a cyanide tail gas absorption device for primary flocculation and sedimentation, which are connected in sequence.
[0013] Preferably, the solid-liquid separation system is a pressure filter, a sand filter, a vacuum filter, a sedimentation filter, or a ceramic membrane filter.
[0014] Preferably, the first oxidant is sodium hypochlorite, calcium hypochlorite, ozone, percarbonate, chlorine, or persulfate; the primary cyanide oxidation system includes a first oxidant preparation device, a first oxidant dosing device, a closed mixing device for primary cyanide oxidation, and a cyanide tail gas absorption device for primary cyanide oxidation, connected in sequence.
[0015] Preferably, the second oxidant is sodium hypochlorite, calcium hypochlorite, ozone, or chlorine; the secondary cyanide oxidation system includes a second oxidant preparation device, a second oxidant dosing device, a closed mixing device for secondary cyanide oxidation, and a cyanide tail gas absorption device for secondary cyanide oxidation, connected in sequence.
[0016] Preferably, the second flocculant is one or more of polyferric sulfate, polyaluminum chloride, and polyacrylamide; the secondary flocculation and sedimentation system includes a second flocculant preparation device, a second flocculant dosing device, a closed mixing device for secondary flocculation and sedimentation, and a cyanide tail gas absorption device for secondary flocculation and sedimentation connected in sequence.
[0017] Preferably, the acidification system can adjust the pH value of the cyanide-containing wastewater after precipitation to 2-4; the crystallization aging system can adjust the pH value of the acidified cyanide-containing wastewater to 3-6; the primary cyanide-breaking oxidation system can adjust the pH value of the filtrate to 10-12; and the secondary cyanide-breaking oxidation system can adjust the pH value of the filtrate after the primary cyanide-breaking oxidation to 7-9.
[0018] This utility model achieves the following technical advantages compared to related technologies:
[0019] The electroplating cyanide-containing wastewater treatment system provided by this utility model includes a cyanide precipitation system, an acidification system, a crystallization and aging system, a primary flocculation and sedimentation system, a solid-liquid separation system, a primary cyanide-breaking oxidation system, a secondary cyanide-breaking oxidation system, and a secondary flocculation and sedimentation system, connected sequentially in the treatment direction of the cyanide-containing wastewater. In use, the cyanide-containing wastewater is fed into the cyanide precipitation system, where a precipitant is added to the wastewater to induce precipitation. The acidification system adds a first acidic substance to the precipitated wastewater to acidify it and induce crystallization and precipitation, improving precipitation and filtration performance. The crystallization and aging system adds a first alkaline substance to the acidified wastewater to induce crystallization and aging, allowing the precipitate to grow further and increasing the precipitation rate. The primary flocculation and sedimentation system adds a first flocculant to the crystallized and aged wastewater to induce flocculation and sedimentation. The process involves several steps: First, a solid-liquid separation system is used to separate the cyanide-containing wastewater after flocculation and sedimentation. The separated primary flocculation and sedimentation sludge can be used for valuable metal recovery, while the separated filtrate enters a primary cyanide-breaking oxidation system for further treatment. In the primary cyanide-breaking oxidation system, a second alkaline substance is added to the filtrate to adjust the pH value, and a first oxidant is added for oxidation to remove cyanide and organic matter. Second, a second acidic substance is added to the filtrate after the primary cyanide-breaking oxidation to adjust the pH value, and a second oxidant is added for oxidation to remove ammonia nitrogen and complexed ions. Finally, a second flocculant is added to the filtrate after the secondary cyanide-breaking oxidation in a secondary flocculation and sedimentation system for flocculation and sedimentation. The resulting secondary flocculation and sedimentation sludge can be used for valuable metal recovery, and the supernatant can be used for SCR (Sequencing Controlled Reduction) treatment of electroplating wastewater to achieve salt and water recovery.
[0020] Compared with existing cyanide-containing wastewater treatment systems, this system offers advantages such as thorough cyanide removal, rapid oxidation reaction, low dosage of oxidizing agents, and low energy consumption. The sludge generated during the treatment process is easily integrated with valuable metal recovery processes to achieve a high recovery rate of valuable metals. Furthermore, the treated wastewater is easily integrated with SCR processes for electroplating wastewater to realize the resource utilization of cyanide-containing copper wastewater. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or related technologies, the drawings used in 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.
[0022] Figure 1 This is a schematic diagram of an electroplating cyanide-containing wastewater treatment system provided in an embodiment of the present invention. Detailed Implementation
[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0024] The purpose of this invention is to provide a cyanide-containing wastewater treatment system for electroplating, which solves the problems existing in related technologies. It can reduce the consumption of chemical oxidants during wastewater treatment and facilitate the recovery of valuable metals. The process is simple and easy to operate.
[0025] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0026] like Figure 1 As shown, this embodiment provides a cyanide-containing wastewater treatment system for electroplating, including a cyanide precipitation system, an acidification system, a crystallization aging system, a primary flocculation sedimentation system, and a solid-liquid separation system connected in sequence.
[0027] In this embodiment, the inlet of the cyanide precipitation system is used to introduce cyanide-containing wastewater. The cyanide precipitation system can add a precipitant to the cyanide-containing wastewater to induce precipitation. Specifically, the precipitant in this embodiment is an iron-containing solution. The cyanide precipitation system adds the iron-containing solution to the cyanide-containing wastewater to carry out the Prussian blue and Prussian blue-like reactions, fixing most of the valuable metals and cyanides into a solid. Further, the precipitant is preferably a ferrous solution. The cyanide precipitation system adds the ferrous solution to the cyanide-containing wastewater to carry out the Prussian blue-like reaction. The cyanide precipitation system includes an iron-containing solution preparation device, an iron-containing solution dosing device, an iron-containing solution reaction device, and a precipitation reaction device connected in sequence.
[0028] In this embodiment, the acidification system can add a first acidic substance to the precipitated cyanide-containing wastewater to acidify it. Specifically, the first acidic substance in this embodiment is one or more of sulfuric acid, hydrochloric acid, and nitric acid. The pH value is adjusted to 2-4 by adding the first acidic substance to the precipitated cyanide-containing wastewater through the acidification system, and the acidification time is 0.5h-1h. The acidification system includes an acid preparation device, an acid dosing device, and a closed mixing device for acidification connected in sequence.
[0029] In this embodiment, the crystallization aging system can add a first alkaline substance to the acidified cyanide-containing wastewater to induce crystallization aging. Specifically, the first alkaline substance in this embodiment is one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide (preferably sodium hydroxide). The first alkaline substance is added to the acidified cyanide-containing wastewater through the crystallization aging system to adjust the pH value to 3-6, thereby neutralizing and aging the wastewater. The crystallization aging system includes an alkali preparation device, an alkali addition device, a closed mixing device for crystallization aging, and a cyanide tail gas absorption device for crystallization aging, which are connected in sequence.
[0030] In this embodiment, the primary flocculation sedimentation system can add a first flocculant to the crystallized and aged cyanide-containing wastewater to induce flocculation and sedimentation. Specifically, the first flocculant in this embodiment is one or more of polyferric sulfate, polyaluminum chloride, and polyacrylamide (preferably polyacrylamide). The primary flocculation sedimentation system adds the first flocculant to the crystallized and aged cyanide-containing wastewater to induce flocculation and sedimentation. The primary flocculation sedimentation system includes a first flocculant preparation device, a first flocculant dosing device, a closed mixing device for primary flocculation and sedimentation, and a cyanide tail gas absorption device for primary flocculation and sedimentation, which are connected in sequence.
[0031] In this embodiment, the solid-liquid separation system can separate the cyanide-containing wastewater after flocculation and sedimentation. The liquid phase outlet of the solid-liquid separation system is used to discharge the filtrate, and the solid phase outlet of the solid-liquid separation system is used to discharge the primary flocculation and sedimentation sludge. Specifically, the solid-liquid separation system in this embodiment is a filter press, a sand filter, a vacuum filter, a sedimentation filter, or a ceramic membrane filter. Further, the solid-liquid separation system is preferably a filter press, which filters the cyanide-containing wastewater after flocculation and sedimentation. It has a high level of automation and low cost. The primary flocculation and sedimentation sludge obtained after filter press can be used for valuable metal recovery through a valuable metal recovery process, and the filtrate obtained after filter press enters the primary cyanide destruction and oxidation system for further treatment.
[0032] The electroplating cyanide-containing wastewater treatment system provided in this embodiment also includes a primary cyanide-breaking oxidation system, a secondary cyanide-breaking oxidation system, and a secondary flocculation and sedimentation system connected in sequence.
[0033] In this embodiment, the liquid phase outlet of the solid-liquid separation system is connected to the inlet of the primary cyanide oxidation system. The primary cyanide oxidation system can add a second alkaline substance and a first oxidant to the filtrate to remove cyanide and organic matter. Specifically, the first oxidant in this embodiment is sodium hypochlorite, calcium hypochlorite, ozone, percarbonate, chlorine, or persulfate (preferably ozone, followed by sodium hypochlorite). The primary cyanide oxidation system adjusts the pH value to 10-12 by adding a second alkaline substance to the filtrate and then adds the first oxidant to oxidize for 0.5-1 hour to deeply remove cyanide and organic matter, oxidizing the cyanide to cyanide oxycyanide (CNO), so that the cyanide content in the filtrate is less than 0.05 ppm. The primary cyanide oxidation system includes a first oxidant preparation device, a first oxidant dosing device, a closed mixing device for primary cyanide oxidation, and a cyanide tail gas absorption device for primary cyanide oxidation, connected in sequence.
[0034] In this embodiment, the secondary cyanide oxidation system can add a second acidic substance and a second oxidant to the filtrate after the primary cyanide oxidation to remove ammonia nitrogen and complexed ions. Specifically, the second oxidant in this embodiment is sodium hypochlorite, calcium hypochlorite, ozone, or chlorine (preferably sodium hypochlorite, followed by ozone). By adding the second acidic substance to the filtrate after the primary cyanide oxidation to adjust the pH value to 7-9, and adding the second oxidant to the filtrate after the primary cyanide oxidation, ammonia nitrogen and complexed ions are deeply removed, so that the ammonia nitrogen content in the filtrate after the primary cyanide oxidation is less than 5 ppm. The secondary cyanide oxidation system includes a second oxidant preparation device, a second oxidant dosing device, a closed mixing device for secondary cyanide oxidation, and a cyanide tail gas absorption device for secondary cyanide oxidation, connected in sequence.
[0035] In this embodiment, the secondary flocculation and sedimentation system can add a second flocculant to the filtrate after secondary cyanide oxidation to induce flocculation and sedimentation. The liquid phase outlet of the secondary flocculation and sedimentation system is used to discharge the supernatant, and the solid phase outlet is used to discharge the secondary flocculated and sedimented sludge. Specifically, the second flocculant in this embodiment is one or more of polyferric sulfate, polyaluminum chloride, and polyacrylamide. By adding the second flocculant to the filtrate after secondary cyanide oxidation through the secondary flocculation and sedimentation system, the resulting secondary flocculated and sedimented sludge can be used for valuable metal recovery through a valuable metal recovery process. The resulting supernatant (with a valuable metal content of less than 0.3 ppm) can be treated by the SCR process for electroplating wastewater, and then meet the wastewater discharge standards or be reused as reclaimed water. The secondary flocculation and sedimentation system includes a second flocculant preparation device, a second flocculant dosing device, a closed mixing device for secondary flocculation and sedimentation, and a cyanide tail gas absorption device for secondary flocculation and sedimentation, connected in sequence.
[0036] Application Example 1
[0037] A Prussian blue-like reaction is initiated by introducing a ferrous solution (ferrous molar concentration 0.5 times that of cyanide, cyanide concentration 2000 ppm) into cyanide-containing wastewater through a cyanide precipitation system. A first acidic substance is added to the cyanide-containing wastewater containing the ferrous solution to adjust the pH to 2.5 through an acidification system. A first alkaline substance is added to the acidified cyanide-containing wastewater through a crystallization and aging system to adjust the pH to 3.0 for further aging. A first flocculant is added to the crystallized and aged cyanide-containing wastewater (suspension) through a primary flocculation and sedimentation system for flocculation and sedimentation. Finally, the flocculated and sedimented cyanide-containing wastewater is pressurized through a solid-liquid separation system. The Prussian blue sludge obtained after filtration and pressure filtration can be used for copper recovery. The filtrate (containing 100 ppm cyanide) is passed through a primary cyanide-removing oxidation system, and an appropriate amount of a second alkaline substance is introduced to adjust the pH to 11. Ozone (3 times the amount of cyanide) is then added for 1 hour to deeply remove cyanide and organic matter. The filtrate after primary cyanide-removing oxidation is then adjusted to pH 8 through a secondary cyanide-removing oxidation system, and 10% sodium hypochlorite (60 times the concentration of ammonia nitrogen) is added to deeply remove ammonia nitrogen and complexed ions. A second flocculant is added to the ammonia nitrogen-removed filtrate through a secondary flocculation and sedimentation system for flocculation and sedimentation, allowing for copper recovery from the sludge. The supernatant is then treated using an SCR process for electroplating wastewater, achieving salt and water recovery.
[0038] Application Example 2
[0039] The difference between this application example and Application Example 1 is that stable control of experimental results can still be achieved even when the system influent fluctuates significantly. A Prussian blue-like reaction is initiated by introducing a ferrous solution (ferrous molar concentration 0.25 times that of cyanide, cyanide concentration 2500 ppm) into the cyanide-containing wastewater through a cyanide precipitation system. A first acidic substance is added to the cyanide-containing wastewater containing a certain amount of ferrous solution through an acidification system to adjust the pH to 3.5, thus acidifying it. A first alkaline substance is added to the acidified cyanide-containing wastewater through a crystallization and aging system for further aging. A first flocculant is added to the crystallized and aged cyanide-containing wastewater (suspension) through a primary flocculation and sedimentation system for flocculation and sedimentation. The flocculated and sedimented cyanide-containing wastewater is then filtered through a solid-liquid separation system. The Prussian blue mud can be used for copper recovery. The filtrate (containing 150 ppm cyanide) after pressure filtration is adjusted to pH 11 by introducing a suitable amount of a second alkaline substance through a primary cyanide-removal oxidation system. Sodium hypochlorite (40 times the amount of cyanide) is then added for oxidative treatment for 0.5-1 hours to deeply remove cyanide and organic matter. The pH of the liquid after primary cyanide-removal oxidation is adjusted to 8 through a secondary cyanide-removal oxidation system, and 10% sodium hypochlorite (60 times the concentration of ammonia nitrogen) is added for further cyanide removal. A second flocculant is added to the liquid after cyanide removal through a secondary flocculation and sedimentation system for flocculation and sedimentation. Copper is recovered from the sludge, and the supernatant is treated using an SCR process for electroplating wastewater, achieving salt and water recovery.
[0040] It should be noted that in the treatment process of electroplating cyanide-containing wastewater, this system selects chemical precipitation to remove a large number of cyanide ions in the wastewater. This method only requires a very small amount of oxidant to deeply break down the cyanide and produces ammonia nitrogen. After breaking down the cyanide, a small amount of hypochlorite ions are used to continue to completely oxidize the ammonia nitrogen into nitrogen gas, ultimately achieving the enrichment and recovery of water, salt, and valuable metals.
[0041] In summary, this system has the following advantages:
[0042] First, this system uses Prussian blue-like precipitation to first fix a large amount of CN and valuable metals in the cyanide-containing wastewater from electroplating, which greatly saves the consumption of oxidizing chemical agents and only requires a very small amount of ordinary agents.
[0043] Secondly, this system has high wastewater treatment efficiency, good environmental benefits, and a simple process flow. It can achieve linkage control through simple pH, pumps, and ORP. Except for the dosing, everything else can be automatically controlled, which simplifies equipment requirements, reduces energy consumption, and is suitable for large-scale industrial production. It not only reduces the environmental pressure on enterprises but also brings additional economic benefits.
[0044] Third, this system reduces the consumption of chlorine oxidizing agents and uses greener ozone, while achieving deep removal of cyanide and organic matter, reducing salt content, and also reducing the emission of cyanide-containing gases.
[0045] Fourth, because this system uses alkaline cyanide oxidation, its reaction time is shorter than that of Fenton and Fenton-like systems, which is beneficial for the miniaturization of the reaction tank.
[0046] Fifth, the supernatant after treatment by this system can be used for reclaimed water reuse after being treated by the SCR process for electroplating wastewater, with a water resource reuse rate of over 95%.
[0047] This utility model uses specific examples to illustrate its principles and implementation methods. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the idea of this utility model. In summary, the content of this specification should not be construed as a limitation of this utility model.
Claims
1. A system for treating cyanide-containing wastewater from electroplating, characterized in that: The system comprises, in sequence, a cyanide precipitation system, an acidification system, a crystallization and aging system, a primary flocculation and sedimentation system, and a solid-liquid separation system. The inlet of the cyanide precipitation system is used to introduce cyanide-containing wastewater, and the system can add a precipitant to the cyanide-containing wastewater to induce precipitation. The acidification system can add a first acidic substance to the precipitated cyanide-containing wastewater to acidify it. The crystallization and aging system can add a first alkaline substance to the acidified cyanide-containing wastewater to induce crystallization and aging. The primary flocculation and sedimentation system can add a first flocculant to the crystallized and aged cyanide-containing wastewater to induce flocculation and sedimentation. The solid-liquid separation system can separate the flocculated and sedimented cyanide-containing wastewater into solid and liquid phases. The liquid phase outlet of the solid-liquid separation system is used to discharge filtrate, and the solid phase outlet of the solid-liquid separation system is used to discharge primary flocculation and sedimentation sludge. It also includes a primary cyanide oxidation system, a secondary cyanide oxidation system, and a secondary flocculation and sedimentation system connected in sequence. The liquid phase outlet of the solid-liquid separation system is connected to the inlet of the primary cyanide oxidation system. The primary cyanide oxidation system can add a second alkaline substance and a first oxidant to the filtrate to remove cyanide and organic matter. The secondary cyanide oxidation system can add a second acidic substance and a second oxidant to the filtrate after primary cyanide oxidation to remove ammonia nitrogen and complexed ions. The secondary flocculation and sedimentation system can add a second flocculant to the filtrate after secondary cyanide oxidation to induce flocculation and sedimentation. The liquid phase outlet of the secondary flocculation and sedimentation system is used to discharge the supernatant, and the solid phase outlet of the secondary flocculation and sedimentation system is used to discharge the secondary flocculated and settled sludge.
2. The electroplating cyanide-containing wastewater treatment system according to claim 1, characterized in that: The precipitant is an iron-containing solution; the cyanide precipitation system includes an iron-containing solution preparation device, an iron-containing solution dosing device, an iron-containing solution reaction device, and a precipitation reaction device connected in sequence.
3. The electroplating cyanide-containing wastewater treatment system according to claim 1, characterized in that: The first acidic substance is one or more of sulfuric acid, hydrochloric acid, and nitric acid; the acidification system includes an acid preparation device, an acid dosing device, and a closed mixing device for acidification connected in sequence.
4. The electroplating cyanide-containing wastewater treatment system according to claim 1, characterized in that: The first alkaline substance is one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide; the crystallization aging system includes an alkali preparation device, an alkali addition device, a closed mixing device for crystallization aging, and a cyanide tail gas absorption device for crystallization aging, which are connected in sequence.
5. The electroplating cyanide-containing wastewater treatment system according to claim 1, characterized in that: The first flocculant is one or more of polyferric sulfate, polyaluminum chloride, and polyacrylamide; the primary flocculation and sedimentation system includes a first flocculant preparation device, a first flocculant dosing device, a closed mixing device for primary flocculation and sedimentation, and a cyanide tail gas absorption device for primary flocculation and sedimentation, which are connected in sequence.
6. The electroplating cyanide-containing wastewater treatment system according to claim 1, characterized in that: The solid-liquid separation system is a pressure filter, a sand filter, a vacuum filter, a sedimentation filter, or a ceramic membrane filter.
7. The electroplating cyanide-containing wastewater treatment system according to claim 1, characterized in that: The first oxidant is sodium hypochlorite, calcium hypochlorite, ozone, percarbonate, chlorine, or persulfate; the primary cyanide oxidation system includes a first oxidant preparation device, a first oxidant dosing device, a closed mixing device for primary cyanide oxidation, and a cyanide tail gas absorption device for primary cyanide oxidation, which are connected in sequence.
8. The electroplating cyanide-containing wastewater treatment system according to claim 1, characterized in that: The second oxidant is sodium hypochlorite, calcium hypochlorite, ozone, or chlorine; the secondary cyanide oxidation system includes a second oxidant preparation device, a second oxidant dosing device, a closed mixing device for secondary cyanide oxidation, and a cyanide tail gas absorption device for secondary cyanide oxidation, which are connected in sequence.
9. The electroplating cyanide-containing wastewater treatment system according to claim 1, characterized in that: The second flocculant is one or more of polyferric sulfate, polyaluminum chloride, and polyacrylamide; the secondary flocculation and sedimentation system includes a second flocculant preparation device, a second flocculant dosing device, a closed mixing device for secondary flocculation and sedimentation, and a cyanide tail gas absorption device for secondary flocculation and sedimentation connected in sequence.
10. The electroplating cyanide-containing wastewater treatment system according to any one of claims 1-9, characterized in that: The acidification system can adjust the pH value of the cyanide-containing wastewater after precipitation to 2-4; the crystallization and aging system can adjust the pH value of the acidified cyanide-containing wastewater to 3-6; the primary cyanide-breaking oxidation system can adjust the pH value of the filtrate to 10-12; and the secondary cyanide-breaking oxidation system can adjust the pH value of the filtrate after the primary cyanide-breaking oxidation to 7-9.