Cyanide-containing wastewater treatment system

Abstract

The utility model discloses a cyanide-containing wastewater treatment system, which relates to the technical field of wastewater treatment equipment, and comprises a precipitation system, an oxidation system and an ammonia breaking system which can be sequentially communicated, the oxidation system can be used for carrying out oxidation reaction on cyanide in supernate discharged from the precipitation system; and the ammonia breaking system is used for removing ammonia nitrogen and complex ions in the wastewater treated by the oxidation system. The wastewater treatment device can reduce the dosage of chemicals, reduce the wastewater treatment cost and improve the wastewater treatment effect.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment equipment technology, and in particular to a cyanide-containing wastewater treatment system. Background Technology

[0002] Cyanide electroplating products are increasingly widely used in high-precision fields such as aviation, aerospace, and integrated circuits due to their superior coating quality and strong corrosion resistance, and are difficult to replace in the short term. Cyanide-containing wastewater mainly originates from the electroplating and smelting processes of gold, silver, and copper. This wastewater contains high levels and concentrations of cyanide, making it highly toxic. In addition to highly toxic cyanide, it also contains valuable heavy metals and additives.

[0003] Currently, cyanide-containing wastewater is mostly treated using the chlorine-oxygen oxidation method. This method utilizes chlorine-based oxidants to oxidize and decompose cyanide in the wastewater into non-toxic or low-toxic substances. The treatment methods include: First, adding alkaline substances such as sodium hydroxide to the wastewater to adjust the pH to 10-11, and then using chlorine-based oxidants (such as liquid chlorine, sodium hypochlorite, bleaching powder, etc.) to oxidize and decompose the wastewater; Second, adding acidic substances such as sulfuric acid to the wastewater to adjust the pH to 7-8, and then adding chlorine-based oxides to oxidize and decompose the wastewater into CO2 and H2O. This method requires a large amount of oxidants, necessitates repeated pH adjustments, and results in high treatment costs.

[0004] Another existing method for treating cyanide-containing wastewater is electrolysis. During the electrolysis reaction, free radicals are generated that can react directly and non-selectively with pollutants in the wastewater, oxidizing and destroying them. Meanwhile, the cathode reduces some heavy metals to elemental forms for recovery. However, electrolysis consumes excessive energy, the electrolysis equipment is expensive, the processing capacity is small, and the labor intensity is high, resulting in high wastewater treatment costs. Utility Model Content

[0005] The purpose of this invention is to provide a cyanide-containing wastewater treatment system to solve the problems existing in the prior art, thereby reducing the amount of reagents used, reducing wastewater treatment costs, and improving wastewater treatment efficiency.

[0006] To achieve the above objectives, this utility model provides the following solution:

[0007] This utility model provides a cyanide-containing wastewater treatment system, comprising a sedimentation system, an oxidation system, and an ammonia destruction system that are connected in sequence, wherein:

[0008] The precipitation system is used to precipitate cyanide in the cyanide-containing wastewater to be treated;

[0009] The oxidation system enables the cyanide in the supernatant discharged from the precipitation system to undergo an oxidation reaction.

[0010] The ammonia-removing system is used to remove ammonia nitrogen and complexed ions from wastewater treated by the oxidation system.

[0011] Preferably, the oxidation system is an autocatalytic oxidation system.

[0012] Preferably, the system further includes a pH adjustment system and a solid-liquid separation system. The inlet and outlet of the pH adjustment system are connected to the outlet of the sedimentation system and the inlet of the solid-liquid separation system, respectively. The outlet of the solid-liquid separation system is connected to the inlet of the oxidation system. The pH adjustment system can adjust the pH of the wastewater treated by the sedimentation system. The solid-liquid separation system can separate the solids and liquids in the wastewater treated by the pH adjustment system. The oxidation system can oxidize the cyanide in the filtrate separated by the solid-liquid separation system.

[0013] Preferably, the pH adjustment system includes an acidification unit and a crystallization and aging unit. The inlet and outlet of the acidification unit are connected to the outlet of the precipitation system and the inlet of the crystallization and aging unit, respectively. The outlet of the crystallization and aging unit is connected to the inlet of the solid-liquid separation system. The acidification unit can acidify the wastewater treated by the precipitation system and precipitate the cyanide in the wastewater. The crystallization and aging unit can adjust the pH of the wastewater treated by the acidification unit and crystallize, grow, and age the cyanide in the wastewater. The solid-liquid separation system can separate the solid and liquid components of the wastewater treated by the crystallization and aging unit.

[0014] Preferably, it further includes a first flocculation sedimentation system, the inlet and outlet of which are connected to the outlet of the crystallization aging unit and the inlet of the solid-liquid separation system, respectively; the first flocculation sedimentation system enables particles in the wastewater treated by the crystallization aging unit to form flocculent precipitates; the solid-liquid separation system enables solid-liquid separation of the wastewater treated by the first flocculation sedimentation system and the flocculent precipitates.

[0015] Preferably, it also includes a second flocculation sedimentation system, the inlet of which is connected to the outlet of the ammonia breaking system, and the second flocculation sedimentation system can cause particles in the wastewater treated by the ammonia breaking system to form flocculent precipitates.

[0016] Preferably, it also includes an SCR system, the inlet of which is connected to the outlet of the second flocculation sedimentation system, and the SCR system is capable of recovering salt and water from the supernatant discharged from the second flocculation sedimentation system.

[0017] Preferably, it also includes a metal recovery system, which is capable of recovering metals from the solids separated in the solid-liquid separation system, and the metal recovery system is capable of recovering metals from the flocculent precipitates separated in the second flocculation sedimentation system.

[0018] Preferably, the precipitation system, the acidification unit, the crystallization and aging unit, the first flocculation and sedimentation system, the oxidation system, the ammonia breaking system, and the second flocculation and sedimentation system all include a dosing unit, an automatic dosing unit, and a reaction unit. The automatic dosing unit of the precipitation system can add the reagent prepared by the dosing unit of the precipitation system to the reaction unit of the precipitation system; the automatic dosing unit of the acidification unit can add the reagent prepared by the dosing unit of the acidification unit to the reaction unit of the acidification unit; and the automatic dosing unit of the crystallization and aging unit can add the reagent prepared by the dosing unit of the crystallization and aging unit to the reaction unit of the crystallization and aging unit. The reaction unit described above; the automatic dosing unit of the first flocculation sedimentation system can add the reagent configured by the dosing unit of the first flocculation sedimentation system to the reaction unit of the first flocculation sedimentation system; the automatic dosing unit of the oxidation system can add the reagent configured by the dosing unit of the oxidation system to the reaction unit of the oxidation system; the automatic dosing unit of the ammonia breaking system can add the reagent configured by the dosing unit of the ammonia breaking system to the reaction unit of the ammonia breaking system; the automatic dosing unit of the second flocculation sedimentation system can add the reagent configured by the dosing unit of the second flocculation sedimentation system to the reaction unit of the second flocculation sedimentation system.

[0019] Preferably, the crystallization aging unit, the first flocculation sedimentation system, the oxidation system, the ammonia breaking system, and the second flocculation sedimentation system all further include an exhaust gas treatment unit for exhaust gas treatment.

[0020] The present invention achieves the following technical advantages over the prior art:

[0021] This invention provides a cyanide-containing wastewater treatment system, comprising a sedimentation system, an oxidation system, and an ammonia-removal system connected in sequence. The sedimentation system precipitates cyanide in the wastewater; the oxidation system oxidizes the cyanide in the supernatant discharged from the sedimentation system; and the ammonia-removal system removes ammonia nitrogen and complex ions from the wastewater after oxidation. This invention first precipitates cyanide in the wastewater through the sedimentation system, reducing the amount of cyanide to be oxidized and decomposed in subsequent processes, thereby reducing reagent usage and treatment costs. Simultaneously, this invention removes ammonia nitrogen and complex ions from the wastewater, improving the wastewater treatment efficiency. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, 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.

[0023] Figure 1 A schematic diagram of the cyanide-containing wastewater treatment system provided by this utility model;

[0024] In the diagram: 100, Cyanide-containing wastewater treatment system; 1, Sedimentation system; 2, Acidification unit; 3, Crystallization and aging unit; 4, First flocculation and sedimentation system; 5, Solid-liquid separation system; 6, Oxidation system; 7, Ammonia destruction system; 8, Second flocculation and sedimentation system; 9, SCR system; 10, Metal recovery system. Detailed Implementation

[0025] 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.

[0026] The purpose of this invention is to provide a cyanide-containing wastewater treatment system to solve the problems existing in the prior art, thereby reducing the amount of reagents used, reducing wastewater treatment costs, and improving wastewater treatment efficiency.

[0027] 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.

[0028] Example 1

[0029] like Figure 1As shown, this embodiment provides a cyanide-containing wastewater treatment system 100, including a precipitation system 1, an oxidation system 6, and an ammonia-breaking system 7 connected in sequence. The precipitation system 1 precipitates cyanide in the cyanide-containing wastewater; the oxidation system 6 oxidizes the cyanide in the supernatant discharged from the precipitation system 1, achieving cyanide oxidative decomposition; and the ammonia-breaking system 7 removes ammonia nitrogen and complex ions from the wastewater treated by the oxidation system 6. This embodiment first precipitates cyanide in the wastewater through the precipitation system 1 before proceeding to the oxidation system 6 and the ammonia-breaking system 7 for further treatment. This reduces the amount of cyanide to be oxidized and decomposed in subsequent processes, thereby reducing reagent usage and lowering treatment costs. Simultaneously, this embodiment effectively removes ammonia nitrogen and complex ions from the wastewater, improving wastewater treatment efficiency.

[0030] Furthermore, the precipitation system 1 can introduce an iron-containing solution into the wastewater to carry out Prussian blue and Prussian blue-like reactions, effectively fixing copper and cyanide (CN) in the wastewater and converting them into solid precipitates for removal. This solid precipitate can be directly recovered from copper via pyrometallurgical processes and the cyanide completely decomposed, significantly reducing the consumption of oxidizing chemicals. The ammonia-removing system 7 can adjust the pH of the post-oxidation liquid from the oxidation system 6 to 7-10, and then add chlorine-containing oxidizing agents for deep removal of ammonia nitrogen and complexed ions. The chlorine-containing oxidizing agents mainly include strong oxidizing agents such as calcium hypochlorite and sodium hypochlorite. Preferably, the ammonia-removing system 7 can adjust the pH of the post-oxidation liquid from the oxidation system 6 to 8-9, and sodium hypochlorite is selected as the chlorine-containing oxidizing agent, resulting in an ammonia nitrogen concentration of less than 5 ppm after treatment.

[0031] Furthermore, oxidation system 6 is a self-catalytic oxidation system. In this system, cyanide is oxidized to cyanide (CNO) by adding an oxidizing agent to the waste liquid, which is then hydrolyzed into ammonium ions and carbon dioxide. The metal ions generated during the reaction (such as Fe2+ and Cu2+) catalyze the oxidation reaction, accelerating the decomposition of cyanide, reducing the consumption of chlorine oxidizing agents, and improving treatment efficiency. The oxidizing agents mainly include strong oxidizing agents such as hydrogen peroxide, persulfate, and percarbonate.

[0032] Preferably, hydrogen peroxide is used as the oxidizing agent, which is more environmentally friendly and can also deeply remove cyanide and organic matter from wastewater.

[0033] Furthermore, this embodiment also includes a pH adjustment system and a solid-liquid separation system 5. The inlet and outlet of the pH adjustment system are connected to the outlet of the sedimentation system 1 and the inlet of the solid-liquid separation system 5, respectively. The outlet of the solid-liquid separation system 5 is connected to the inlet of the oxidation system 6. The pH adjustment system can adjust the pH of the wastewater treated by the sedimentation system 1. The solid-liquid separation system 5 can separate the solid and liquid components of the wastewater treated by the pH adjustment system. The oxidation system 6 can oxidize the cyanide in the filtrate separated by the solid-liquid separation system 5.

[0034] Furthermore, the pH adjustment system includes an acidification unit 2 and a crystallization and aging unit 3. The inlet and outlet of the acidification unit 2 are connected to the outlet of the sedimentation system 1 and the inlet of the crystallization and aging unit 3, respectively. The outlet of the crystallization and aging unit 3 is connected to the inlet of the solid-liquid separation system 5. The acidification unit 2 can acidify the wastewater treated by the sedimentation system 1 and precipitate the cyanide in the wastewater. The crystallization and aging unit 3 can adjust the pH of the wastewater treated by the acidification unit 2 and cause the cyanide in the wastewater to crystallize, grow, and age. The solid-liquid separation system 5 can separate the solid and liquid components of the wastewater treated by the crystallization and aging unit 3. The acidification unit 2 and the crystallization and aging unit 3 achieve further precipitation of cyanide, improve the precipitation rate, and help to further reduce the amount of oxidant used in the subsequent process.

[0035] Furthermore, the acidification unit 2 acidifies the wastewater with acidic substances, including but not limited to one or a combination of sulfuric acid, hydrochloric acid, and nitric acid. The acidification unit 2 preferably adjusts the pH to 2-6.5, more preferably to 2-3, and the acidification time is 0.5-1h.

[0036] Furthermore, the crystallization aging unit 3 adjusts the pH of the acidified cyanide-containing wastewater to a suitable level by adding an alkaline substance, thereby neutralizing and aging the cyanide in the wastewater. Preferably, the pH of the crystallization aging unit 3 is adjusted to 3-6. The added alkaline substance is one or a combination of sodium hydroxide, potassium hydroxide, and calcium hydroxide. More preferably, the pH is adjusted to 4.5-5.5, and the alkaline substance is sodium hydroxide.

[0037] Furthermore, this embodiment also includes a first flocculation sedimentation system 4, the inlet and outlet of which are connected to the outlet of the crystallization aging unit 3 and the inlet of the solid-liquid separation system 5, respectively. The first flocculation sedimentation system 4 enables particles in the wastewater treated by the crystallization aging unit 3 to form flocculent precipitates, thereby improving the effect of subsequent solid-liquid separation. The solid-liquid separation system 5 can perform solid-liquid separation on the wastewater and flocculent precipitates treated by the first flocculation sedimentation system 4, so as to facilitate the separate treatment and utilization of the separated solids and liquids.

[0038] It should be noted that the solid-liquid separation steps of the solid-liquid separation system 5 include one or more steps such as pressure filtration, sand filtration, vacuum filtration, sedimentation, and ceramic membrane filtration. Preferably, the solution after flocculation and sedimentation is subjected to pressure filtration, which has a high level of automation and low cost. The solid-liquid separation system 5 can use products from existing technologies, which will not be elaborated here.

[0039] Furthermore, the cyanide concentration of the filtrate entering the autocatalytic oxidation system from the solid-liquid separation system 5 is less than 200 ppm, the pH of the filtrate is 4.5-5.5, and after adding an appropriate amount of hydrogen peroxide for autocatalytic oxidation for 2 hours, the cyanide concentration is less than 0.05 ppm, thus achieving deep removal of cyanide.

[0040] Furthermore, the first flocculation and sedimentation system 4 adds a flocculant to the neutralized and aged wastewater suspension to cause the particles in the wastewater to flocculate and settle; the added flocculant is one or a combination of polyferric sulfate, polyaluminum chloride, and polyacrylamide. More preferably, the flocculant is polyacrylamide.

[0041] Furthermore, this embodiment also includes a second flocculation sedimentation system 8, whose inlet is connected to the outlet of the ammonia-breaking system 7. The second flocculation sedimentation system 8 enables particles in the wastewater treated by the ammonia-breaking system 7 to form flocculent precipitates. The second flocculation sedimentation system 8 separates the flocculent precipitate and the supernatant into layers, facilitating separate treatment and utilization of the flocculent precipitate and the supernatant. The flocculent precipitate is a metal sludge rich in metals such as copper, facilitating subsequent recovery of the metals from the metal sludge. The flocculant used in the flocculation reaction in the second flocculation sedimentation system 8 is one or a combination of several of polyferric sulfate, polyaluminum chloride, and polyacrylamide. After the above reaction, the copper concentration in the supernatant discharged from the second flocculation sedimentation system 8 can be less than 0.3 ppm.

[0042] Furthermore, this embodiment also includes an SCR system 9, the inlet of which is connected to the outlet of the second flocculation and sedimentation system 8. The SCR system 9 can recover salt and water from the supernatant discharged from the second flocculation and sedimentation system 8. The SCR system 9 enables wastewater to meet discharge standards and recovers and reuses the salt and water therein, reducing resource waste.

[0043] Furthermore, this embodiment also includes a metal recovery system 10, which can recover metals from the solids separated in the solid-liquid separation system 5, and can also recover metals from the flocculent precipitates separated in the second flocculation sedimentation system 8. Specifically, the solids separated in the solid-liquid separation system 5 are Prussian blue mud and Prussian blue-like mud.

[0044] Furthermore, the precipitation system 1, acidification unit 2, crystallization and aging unit 3, first flocculation and sedimentation system 4, oxidation system 6, ammonia breaking system 7, and second flocculation and sedimentation system 8 all include a dosing unit, an automatic dosing unit, and a reaction unit. The automatic dosing unit of the precipitation system 1 can add the reagent prepared by the dosing unit of the precipitation system 1 to the reaction unit of the precipitation system 1; the automatic dosing unit of the acidification unit 2 can add the reagent prepared by the dosing unit of the acidification unit 2 to the reaction unit of the acidification unit 2; and the automatic dosing unit of the crystallization and aging unit 3 can add the reagent prepared by the dosing unit of the crystallization and aging unit 3 to the crystallization and aging unit. The reaction unit of the first flocculation sedimentation system 4; the automatic dosing unit of the first flocculation sedimentation system 4 can add the reagent prepared by the dosing unit of the first flocculation sedimentation system 4 to the reaction unit of the first flocculation sedimentation system 4; the automatic dosing unit of the oxidation system 6 can add the reagent prepared by the dosing unit of the oxidation system 6 to the reaction unit of the oxidation system 6; the automatic dosing unit of the ammonia breaking system 7 can add the reagent prepared by the dosing unit of the ammonia breaking system 7 to the reaction unit of the ammonia breaking system 7; the automatic dosing unit of the second flocculation sedimentation system 8 can add the reagent prepared by the dosing unit of the second flocculation sedimentation system 8 to the reaction unit of the second flocculation sedimentation system 8.

[0045] Furthermore, the dosing unit of precipitation system 1 is used to prepare ferrous solution. The reaction device of precipitation system 1 is divided into a ferrous reaction device and a precipitation reaction device. The ferrous reaction device is used to react wastewater with ferrous solution, and the precipitation reaction device is used to precipitate the wastewater after the reaction. The ferrous reaction device and the precipitation reaction device can process simultaneously, which is beneficial to improving treatment efficiency. The reaction units of acidification unit 2, crystallization aging unit 3, first flocculation sedimentation system 4, oxidation system 6, ammonia destruction system 7, and second flocculation sedimentation system 8 are all closed reaction units.

[0046] Furthermore, the sedimentation system 1, acidification unit 2, crystallization and aging unit 3, first flocculation and sedimentation system 4, solid-liquid separation system 5, oxidation system 6, ammonia destruction system 7, second flocculation and sedimentation system 8, and SCR system 9 are all connected by pumps. pH detection devices are installed in each system or unit involving pH adjustment. All automatic dosing units, pumps, and pH detection devices are connected to the control system to achieve automatic dosing and pumping of wastewater between adjacent units or systems. The dosage of acid and alkali reagents in the corresponding automatic dosing unit is adjusted based on the pH value feedback from the pH detection device. ORP water quality analysis and measurement devices are installed in systems and units such as SCR system 9 to continuously monitor the ORP value of the wastewater. When the monitored ORP value is less than or equal to the minimum value of the set ORP value range, precipitating and oxidizing agents are added. When the monitored ORP value is greater than the maximum value of the set ORP value range, the reaction of the corresponding unit or system is determined to be up to standard, and the addition of precipitating and oxidizing agents is stopped to proceed to the next reaction step. The above settings can improve the automation level of wastewater treatment, thereby increasing production efficiency, meeting the needs of large-scale industrial production, and yielding high economic benefits.

[0047] Furthermore, the crystallization aging unit 3, the first flocculation sedimentation system 4, the oxidation system 6, the ammonia breaking system 7, and the second flocculation sedimentation system 8 all include an exhaust gas treatment unit for treating the exhaust gas, thereby reducing the pollution of the exhaust gas to the environment. Specifically, the exhaust gas treatment units of the crystallization aging unit 3, the first flocculation sedimentation system 4, the oxidation system 6, the ammonia breaking system 7, and the second flocculation sedimentation system 8 are respectively capable of treating the exhaust gas generated after the reaction in the crystallization aging unit 3, the first flocculation sedimentation system 4, the oxidation system 6, the ammonia breaking system 7, and the second flocculation sedimentation system 8.

[0048] The cyanide-containing wastewater treatment system of this embodiment can be used to treat cyanide-containing wastewater containing at least one metal such as copper or iron. In this embodiment, chemical precipitation is used to remove the large amount of cyanide ions in the wastewater. Only a very small amount of oxidant is needed for further cyanide removal. After cyanide removal, a small amount of hypochlorite ions is used to completely oxidize the ammonia nitrogen produced in the cyanide removal reaction into nitrogen gas, ultimately achieving the enrichment and recovery of water, salt, and copper, with a water resource reuse rate of over 95%. This embodiment is highly efficient, environmentally friendly, and suitable for large-scale industrial production, reducing the environmental burden on enterprises while bringing good economic benefits. Because the amount of subsequent chemical reagents used is relatively small, the treatment difficulty of subsequent processes after precipitation is reduced. Even with large fluctuations in the wastewater influent volume, the subsequent processes can still be well controlled stably.

[0049] Example 2

[0050] This embodiment provides a treatment system for electroplating wastewater containing cyanide copper, including a precipitation system 1, an acidification unit 2, a crystallization and aging unit 3, a first flocculation and sedimentation system 4, a solid-liquid separation system 5, an autocatalytic oxidation system, an ammonia breaking system 7, a second flocculation and sedimentation system 8, and an SCR system 9. The precipitation system 1, acidification unit 2, crystallization and aging unit 3, first flocculation and sedimentation system 4, solid-liquid separation system 5, autocatalytic oxidation system, ammonia breaking system 7, second flocculation and sedimentation system 8, and SCR system 9 are connected in sequence according to the treatment direction of cyanide copper wastewater. Precipitation system 1 introduces a ferrous solution of a certain concentration into the electroplating wastewater containing cyanide. The ferrous molar concentration is 0.5 times that of cyanide, and the cyanide concentration is 2000 ppm. Acidification unit 2 adds an acidic substance to the electroplating wastewater containing cyanide after a certain amount of ferric solution has been introduced to adjust the pH of the wastewater to 2.5, thus acidifying it. Crystallization and aging unit 3 adds an alkaline substance to the acidified electroplating wastewater containing cyanide to adjust the pH to 3.0, further aging it. First flocculation and sedimentation system 4 adds a flocculant to the neutralized and aged suspension of electroplating wastewater containing cyanide, allowing for flocculation and sedimentation. Solid-liquid separation system 5 performs pressure filtration on the flocculated and sedimented solution, and the filtered solution is then filtered to obtain a liquid similar to... Lhasa blue mud can be used for copper recovery; the wastewater filtrate after pressure filtration, containing 100 ppm of cyanide, enters the autocatalytic oxidation system. The autocatalytic oxidation system introduces an appropriate amount of acidic substance into the filtrate to adjust the pH to 2.8, and adds hydrogen peroxide at twice the COD level, and carries out the autocatalytic oxidation reaction for 2-4 hours to deeply remove organic matter and cyanide; the ammonia removal system 7 adjusts the pH of the oxidized liquid to 9, adds 10% sodium hypochlorite (concentration 60 times that of ammonia nitrogen), and deeply removes ammonia nitrogen; the second flocculation and sedimentation system 8 causes the liquid after ammonia nitrogen removal to flocculate and settle, and the obtained sludge is used for copper recovery. The obtained supernatant enters the SCR system 9 for salt and water recovery.

[0051] Example 3

[0052] This embodiment provides a treatment system for electroplating wastewater containing cyanide copper, and the specific treatment method is as follows:

[0053] Precipitation system 1 introduces a ferrous solution of a certain concentration into the electroplating wastewater containing cyanide. The ferrous molar concentration is 0.25 times that of cyanide, and the cyanide concentration is 2500 ppm. Acidification unit 2 adds an acidic substance to the electroplating wastewater containing cyanide after a certain amount of ferric solution has been introduced, adjusting the pH to 3.5 to acidify it. Crystallization and aging unit 3 maintains the pH of the acidified electroplating wastewater containing cyanide at 3.5 for further aging. First flocculation and sedimentation system 4 adds a flocculant to the aged suspension of electroplating wastewater containing cyanide for flocculation and sedimentation. Solid-liquid separation system 5 filters the flocculated and sedimented solution using a pressure filter. Blue mud can be used for copper recovery; the autocatalytic oxidation system introduces an appropriate amount of acidic substance into the cyanide-containing wastewater filtrate after pressure filtration (containing 150 ppm cyanide) to adjust the pH to 3, and adds hydrogen peroxide (twice the amount of COD) for autocatalytic oxidation for 2-4 hours to deeply remove organic matter and cyanide; the ammonia-removing system 7 adjusts the pH of the oxidized liquid to 9.5, adds 10% sodium hypochlorite (75 times the concentration of ammonia nitrogen), and deeply removes ammonia nitrogen; the second flocculation and sedimentation system 8 causes the liquid after ammonia nitrogen removal to undergo flocculation and sedimentation, and the obtained sludge is used for copper recovery, while the obtained supernatant enters the SCR system 9 for salt and water recovery.

[0054] 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 cyanide-containing wastewater treatment system, characterized in that: This includes a precipitation system, an oxidation system, and an ammonia destruction system that can be connected in sequence, wherein: The precipitation system is used to precipitate cyanide in the cyanide-containing wastewater to be treated; The oxidation system includes an oxidation dosing unit, an automatic oxidation dosing unit, and an oxidation reaction unit. The automatic oxidation dosing unit can add the reagent prepared by the oxidation dosing unit to the oxidation reaction unit. The oxidation system oxidizes the cyanide in the supernatant discharged from the precipitation system by adding acidic substances and oxidizing agents to the supernatant discharged from the precipitation system. The ammonia reduction system includes an ammonia reduction dosing unit, an automatic ammonia reduction dosing unit, and an ammonia reduction reaction unit. The automatic ammonia reduction dosing unit can add the reagent prepared by the ammonia reduction dosing unit to the ammonia reduction reaction unit. The ammonia reduction system is used to adjust the pH of the wastewater treated by the oxidation system to 7-10. The ammonia reduction system removes ammonia nitrogen and complexed ions from the wastewater treated by the oxidation system by adding chlorine-containing oxidizing agents.

2. The process for treating cyanide-containing wastewater according to claim 1, characterized by: The oxidation system is an autocatalytic oxidation system.

3. The system for treating cyanide-containing wastewater according to claim 1, wherein: It also includes a pH adjustment system and a solid-liquid separation system. The inlet and outlet of the pH adjustment system are connected to the outlet of the sedimentation system and the inlet of the solid-liquid separation system, respectively. The outlet of the solid-liquid separation system is connected to the inlet of the oxidation system. The pH adjustment system can adjust the pH of the wastewater after it has been treated by the sedimentation system. The solid-liquid separation system can separate solids and liquids in wastewater treated by the pH adjustment system; the oxidation system can oxidize the cyanide in the filtrate separated by the solid-liquid separation system.

4. The process for treating cyanide-containing wastewater according to claim 3, characterized by: The pH adjustment system includes an acidification unit and a crystallization and aging unit. The inlet and outlet of the acidification unit are connected to the outlet of the precipitation system and the inlet of the crystallization and aging unit, respectively. The outlet of the crystallization and aging unit is connected to the inlet of the solid-liquid separation system. The acidification unit can acidify the wastewater treated by the precipitation system and precipitate the cyanide in the wastewater. The crystallization and aging unit can adjust the pH of the wastewater treated by the acidification unit and cause the cyanide in the wastewater to crystallize, grow, and age. The solid-liquid separation system can perform solid-liquid separation on the wastewater after it has been treated by the crystallization and aging unit.

5. The process for treating cyanide-containing wastewater according to claim 4, characterized by: It also includes a first flocculation sedimentation system, the inlet and outlet of which are connected to the outlet of the crystallization aging unit and the inlet of the solid-liquid separation system, respectively; the first flocculation sedimentation system enables particles in the wastewater treated by the crystallization aging unit to form flocculent precipitates; the solid-liquid separation system enables solid-liquid separation of the wastewater and flocculent precipitates from the first flocculation sedimentation system.

6. The process for treating cyanide-containing wastewater according to claim 5, characterized by: It also includes a second flocculation sedimentation system, the inlet of which is connected to the outlet of the ammonia breaking system. The second flocculation sedimentation system can cause particles in the wastewater treated by the ammonia breaking system to form flocculent precipitates.

7. The process for treating cyanide-containing wastewater according to claim 6, characterized by: It also includes an SCR system, the inlet of which is connected to the outlet of the second flocculation sedimentation system, and the SCR system is capable of recovering salt and water from the supernatant discharged from the second flocculation sedimentation system.

8. The process for treating cyanide-containing wastewater according to claim 6, characterized by: It also includes a metal recovery system, which is capable of recovering metals from the solids separated in the solid-liquid separation system, and the metal recovery system is capable of recovering metals from the flocculent precipitates separated in the second flocculation sedimentation system.

9. The process for treating cyanide-containing wastewater according to claim 6, characterized by: The precipitation system, the acidification unit, the crystallization and aging unit, the first flocculation sedimentation system, and the second flocculation sedimentation system all include a dosing unit, an automatic dosing unit, and a reaction unit. The automatic dosing unit of the precipitation system can add the reagent prepared by the dosing unit of the precipitation system to the reaction unit of the precipitation system; the automatic dosing unit of the acidification unit can add the reagent prepared by the dosing unit of the acidification unit to the reaction unit of the acidification unit; the automatic dosing unit of the crystallization and aging unit can add the reagent prepared by the dosing unit of the crystallization and aging unit to the reaction unit of the crystallization and aging unit; the automatic dosing unit of the first flocculation sedimentation system can add the reagent prepared by the dosing unit of the first flocculation sedimentation system to the reaction unit of the first flocculation sedimentation system; and the automatic dosing unit of the second flocculation sedimentation system can add the reagent prepared by the dosing unit of the second flocculation sedimentation system to the reaction unit of the second flocculation sedimentation system.

10. The process for treating cyanide-containing wastewater according to claim 6, wherein: The crystallization aging unit, the first flocculation sedimentation system, the oxidation system, the ammonia breaking system, and the second flocculation sedimentation system all further include an exhaust gas treatment unit for exhaust gas treatment.

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