A method for treating high-cyanide coking wastewater

Abstract

The application provides a method for treating high-cyanide coking wastewater, and belongs to the technical field of wastewater treatment. The method is that the high-cyanide coking wastewater is sequentially subjected to pretreatment, oxidation and photolysis treatment, physical and chemical treatment, biochemical treatment, resin treatment and electrolysis treatment, so that the cyanide content of the treated water is below 0.2 mg / L. The method of the application sequentially passes through six treatment procedures to treat the cyanide in the wastewater, and the cyanide content in the treated wastewater can be below 0.2 mg / L, so that the cyanide removal effect is good.

Description

Technical Field

[0001] This invention relates to the treatment of cyanide, and more particularly to a method for treating high cyanide levels in coking wastewater, belonging to the field of wastewater treatment technology. Background Technology

[0002] Cyanides specifically refer to compounds containing a cyano group (CN), where the carbon and nitrogen atoms are linked by a triple bond. This triple bond gives the cyano group considerable stability, allowing it to exist as a single unit in normal chemical reactions. Because this group exhibits chemical properties similar to halogens, it is often called a pseudohalogen. Most commonly known cyanides are inorganic cyanides, referring to inorganic salts containing a cyanide ion (CN-), which can be considered salts of hydrogen cyanide (HCN). Common examples include potassium cyanide and sodium cyanide. These are often highly toxic. There are also organic cyanides, formed by a cyano group bonded to another carbon atom via a single bond. Depending on the bonding method, organic cyanides can be classified as nitrile (C-CN) and isonitrile (C-NC), and correspondingly, the cyano group can be called a nitrile group (-CN) or an isonitrile group (-NC). Many cyanides that release hydrogen cyanide or cyanide ions upon heating, reaction with acids, or exposure to air and tissues have the same highly toxic effects as hydrogen cyanide.

[0003] Cyanide in coking wastewater is produced during the coke production process due to a series of chemical reactions. The form of cyanide in coking wastewater varies during treatment. Hydrogen cyanide, alkali metal cyanides, and metal cyanide complexes with weak complexing abilities are relatively easy to remove. After biological treatment, the residual cyanide in coking wastewater is mainly composed of highly stable ferricyanide, which is poorly treated by common oxidants. With increasingly stringent environmental requirements and the operation of wastewater reuse and zero-discharge systems, fluctuations in raw water cyanide levels can easily affect the concentrated cyanide levels in the wastewater. Currently, physicochemical processes have limited capacity to reduce cyanide, resulting in effluent cyanide levels approaching or exceeding standards, creating significant environmental pressure. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for treating high-cyanide coking wastewater, solving the technical problem of high cyanide content in effluent and significant environmental pressure caused by the difficulty in treating high-cyanide coking wastewater in existing technologies.

[0005] To achieve the above objectives, the technical solution of a method for treating high-cyanide coking wastewater according to the present invention is as follows: the method involves sequentially subjecting the high-cyanide coking wastewater to pretreatment, biochemical treatment, oxidation and photolysis treatment, physicochemical treatment, resin treatment and electrolysis treatment, thereby obtaining treated water with a cyanide content of less than 0.2 mg / L.

[0006] Furthermore, the pretreatment involves adding cyanide removal agent A to the high-cyanide coking wastewater and stirring, then adding anionic polyacrylamide, stirring, and allowing it to settle before effluent discharge.

[0007] The oxidation and photolysis treatment involves introducing ozone into the pretreated effluent for aeration and stirring, then adding a catalyst, and finally irradiating the effluent with sunlight or ultraviolet light for a predetermined time before effluent is discharged.

[0008] The physical and chemical treatment involves adding cyanide removal agent B to the effluent after oxidation and photolysis treatment, stirring, adding polyacrylamide anion, and then effluent after a predetermined treatment time.

[0009] The biochemical treatment involves first inoculating the water tank with acclimatized cyanide-removing bacteria and adding a carbon source. When the COD in the water tank is degraded to below 500, the effluent after physical and chemical treatment is introduced. After the predetermined treatment time, the water is stirred and allowed to stand. The supernatant is then taken for later use.

[0010] The resin treatment involves transferring the supernatant after biochemical treatment into an ion exchange resin or an adsorption resin for further treatment.

[0011] The electrolysis process involves treating the resin effluent using a carbon rod.

[0012] Furthermore, in the pretreatment, cyanide removal agent A is composed of ferrous sulfate, polyaluminum chloride, and zinc salt. The ferrous sulfate is either ferrous sulfate or ferrous chloride, and the zinc salt is any one of zinc sulfate, zinc chloride, or zinc nitrate. The molar ratio of ferrous sulfate to polyaluminum chloride to zinc salt is 5:3:2. The mass ratio of cyanide to cyanide removal agent A in the high-cyanide coking wastewater is 1:30-40, and the amount of polyacrylamide anion added is 5-10 ppm. In the oxidation and photolysis treatment, the catalyst is prepared according to a titanium dioxide to silicon dioxide mass ratio of 1:1-1.5. The effluent is irradiated with sunlight ≥90,000 lx and ultraviolet light ≥20,000 lx for ≥3.5 hours.

[0013] Furthermore, in the physicochemical treatment, cyanide removal agent B is composed of activated carbon, polyferric sulfate, copper sulfate, cerium oxide, ethylene glycol, and dicyandiamide-formaldehyde condensate in a mass ratio of 2-3:2-3:1-2:1-2:0.2-0.5:1-1.5; after oxidation and photolysis treatment, the mass ratio of cyanide in the effluent to cyanide removal agent B is 1:30-50; the amount of polyacrylamide anion added is 4-7 ppm.

[0014] Furthermore, in the biochemical treatment, the inoculation amount of cyanide-removing bacteria is 10-20% of the wastewater volume in the pool; the carbon source is glucose, and the addition amount is 1000ppm; the environmental conditions of the pool are: temperature 32℃, pH=9, aeration rate ≥2.5L / min; when the effluent after physicochemical treatment is introduced into the biochemical treatment pool, on the first day, a volume less than or equal to 20% of the total volume of cyanide-removing bacteria is introduced, and from the second day onwards, the daily increase in water volume is no more than 1.1 times the previous day's water volume, until the normal influent volume is reached; the biochemical treatment time is ≥30h, and the water is allowed to stand for more than 3 hours.

[0015] Furthermore, in the resin treatment, the resin particle size is 0.4-0.7 mm, and the flow rate is controlled at 2-3 Bv / h.

[0016] Furthermore, in the electrolysis process, multiple sets of carbon rods are selected as the anode and cathode, with a distance of 20-30cm between the carbon rods, a current of 0.3-0.5A, a voltage control of 8-10V, and water is discharged after the electrolysis time exceeds 50 minutes.

[0017] Furthermore, the cyanide content in the high-cyanide coking wastewater is ≥1000 mg / L.

[0018] The beneficial effects of the method for treating high-cyanide coking wastewater according to the present invention are as follows:

[0019] The method of this invention treats cyanide in wastewater through six sequential processing steps: pretreatment, biochemical treatment, oxidation + photolysis treatment, physicochemical treatment, resin treatment, and electrolysis treatment. After treatment, the cyanide content in the wastewater can be reduced to below 0.2 mg / L. This provides more process options and combinations for traditional mainstream physicochemical cyanide removal. It solves the technical problem of high cyanide content in effluent and significant environmental pressure caused by the difficulty in treating high cyanide levels in coking wastewater using existing technologies.

[0020] The basic principles of each step of the treatment process—pretreatment, oxidation and photolysis, physicochemical treatment, biochemical treatment, resin treatment, and electrolytic treatment—are as follows:

[0021] Pretreatment: Ferrous ions in cyanide scavenger A react with free cyanide to form ferrous cyanide. Some ferrous ions react with oxygen to become ferric ions, which then react with the ferrous cyanide to form an insoluble precipitate, Fe4[Fe(CN)6]3, i.e., Prussian blue. The reaction equation is shown below:

[0022] Fe 2+ +6CN － →[Fe(CN)6] 4-

[0023] 12Fe 2+ +3O₂ + 6H₂O → 8Fe 3+ +4Fe(OH)3↓

[0024] 3[Fe(CN)6] 4- +4Fe 3+ =Fe4[Fe(CN)6]3↓

[0025] Oxidation plus photolysis treatment: Ozone treatment utilizes the strong oxidizing properties of ozone to oxidize pollutants in wastewater.

[0026] Photolysis involves using ultraviolet light or natural light as a catalyst, with TiO2 as the catalyst. The light source activates the catalyst, forming electron-hole pairs. The resulting holes are then used to generate hydroxyl radicals. These hydroxyl radicals participate in oxidation reactions, reacting with organic pollutants to convert them into CO2, water, and inorganic salts.

[0027] Physicochemical treatment: Cyanide-containing substances are adsorbed by activated carbon or react with iron ions, copper ions, and cerium ions to form stable complexes, which then rapidly flocculate and precipitate.

[0028] Biochemical treatment: Microorganisms use various related enzymes such as cyanide hydratase and nitrile hydratase in their bodies to catalyze the degradation of cyanide, or to carry out oxidation reactions to react cyanide into ammonia and carbon dioxide, or to form methane and ammonia through reduction reactions, or to generate ammonia and acid through displacement reactions.

[0029] Resin treatment: This method utilizes the active exchange groups of the resin to undergo ion exchange with cyanide, thereby removing organic matter from the water. The exchange groups can be regenerated after use and can be reused. The reaction equation is shown below:

[0030] R-OH+CN - →RCN+OH -

[0031] 2R-OH+Zn(CN - )4 2- →R2Zn(CN)4+2OH -

[0032] 2R-OH+Cu(CN - )4 2- →R2Cu(CN)4+2OH -

[0033] 4R-OH+Fe(CN - )6 2- →R4Cu(CN)6+4OH -

[0034] Electrolysis treatment: Add a small amount of salt before electrolysis and adjust the pH to >7.0. During electrolysis, CN... -CNO is generated at the anode. - CO2, N2, and sodium chloride in the solution provide a large amount of Cl-. - It is oxidized to Cl2, and after Cl2 enters the solution, it hydrolyzes to generate HClO, which enhances the oxidation of cyanide; the metal ions in the solution gain electrons at the cathode and are deposited as metal. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] A method for treating coking wastewater with high cyanide content involves removing cyanide through a series of six treatments: pretreatment, oxidation + photolysis, physicochemical treatment, biochemical treatment, resin treatment, and electrolysis.

[0037] The pretreatment process involves adding cyanide removal agent A to the aerated wastewater, with a cyanide to cyanide removal agent A mass ratio of 1:(30-40). After stirring for at least 30 minutes, 5-10 ppm of polyacrylamide anion is added, followed by stirring for at least 10 minutes. The wastewater is then allowed to settle for at least 3 hours before being discharged to an oxidation + photolysis treatment facility. Preferably, cyanide removal agent A is composed of ferrous sulfate, polyaluminum chloride, and zinc salt. The ferrous sulfate is composed of either ferrous sulfate or ferrous chloride, and the zinc salt is composed of either zinc sulfate, zinc chloride, or zinc nitrate. The proportions of each component are calculated according to a molar ratio of ferrous:aluminum:zinc of 5:3:2.

[0038] The effluent after pretreatment needs to undergo oxidation and photolysis treatment. Ozone is introduced into the wastewater for aeration and stirring. Then, a catalyst is prepared according to the mass ratio of titanium dioxide to silicon dioxide = 1:(1-1.5) and added to the wastewater. At the same time, ≥90,000 lx of sunlight or ≥20,000 lx of ultraviolet radiation is added. After ≥3.5 hours of irradiation, the effluent is discharged.

[0039] The physicochemical treatment involves adding cyanide removal agent B to the wastewater at a ratio of cyanide to cyanide removal agent B of 1:(30-50). After stirring for at least 40 minutes, 4-7 ppm of polyacrylamide anion is added, and after stirring for 10 minutes, the effluent flows to the biological treatment. Preferably, cyanide removal agent B is composed of activated carbon, polyferric sulfate, copper sulfate, cerium oxide, ethylene glycol, and dicyandiamide-formaldehyde condensate. The mass ratio of the six substances is activated carbon: polyferric sulfate: copper sulfate: cerium oxide: ethylene glycol: dicyandiamide-formaldehyde condensate = (2-3):(2-3):(1-2):(1-2):(0.2-0.5):(1-1.5).

[0040] The biological treatment involves first inoculating the water tank with acclimatized cyanide-removing bacteria (commercially available bacterial agents are acceptable; after activation using existing technology, they can be used in the system) at a rate of 10-20%, followed by the addition of 1000 ppm of glucose. The optimal survival conditions for the cyanide-removing bacteria are controlled as follows: temperature 32℃, pH = 9, aeration rate ≥ 2.5 L / min, and biological treatment time ≥ 30 h. After biological treatment, the mixture is stirred and allowed to stand for at least 3 hours. The supernatant is then used for subsequent resin treatment. Once the COD in the tank has decreased to below 500, wastewater can be slowly introduced. The amount of wastewater introduced on the first day should be ≤ 20% of the total volume of the cyanide-removing bacteria, and the daily increase in wastewater volume should not exceed 1.1 times the previous day's volume until the normal influent flow rate is reached.

[0041] The resin used in the treatment is either an ion exchange resin or an adsorption resin, with a particle size of 0.4-0.7 mm and a flow rate controlled at 2-3 Bv / h.

[0042] In the electrolysis process, multiple sets of carbon rods are used as the anode and cathode, with a distance of 20-30cm between the carbon rods, a current of 0.3-0.5A, a voltage control of 8-10V, and water is discharged after electrolysis time of more than 50 minutes.

[0043] Example 1

[0044] The cyanide content in the wastewater of a coking plant in Huai'an, Anhui Province was 1058 mg / L. After pretreatment with 2500 ppm of cyanide removal agent A, the cyanide content in the effluent reached 765 mg / L. After 4 hours of oxidation and photolysis treatment, the cyanide content in the effluent reached 631 mg / L. After physicochemical treatment with 15000 ppm of cyanide removal agent B, the cyanide content in the effluent decreased to 55 mg / L. After 40 hours of biological treatment, the cyanide content in the effluent decreased to 15 mg / L. After resin treatment at a flow rate of 2 BV / h, the cyanide content decreased to 3.5 mg / L. After 1 hour of electrolysis at 10 V and 0.4 A, the cyanide content in the effluent reached 0.11 mg / L.

[0045] In this embodiment, the cyanide removal agent A added during pretreatment is composed of ferrous sulfate, polyaluminum sulfate and zinc sulfate, and the ratio between the components is calculated according to the molar ratio of ferrous sulfate:aluminum:zinc = 5:3:2. After adding the cyanide removal agent, the mixture is stirred for 30 minutes, 5 ppm of polyacrylamide anion is added, and the mixture is stirred for another 15 minutes. After standing and settling for 3 hours, the water is discharged.

[0046] In the oxidation + photolysis step, the catalyst is prepared by titanium dioxide and silicon dioxide in a mass ratio of 1:1, the amount of catalyst added is 2000 mg / L, and the sunlight is irradiated at 100,000 lx.

[0047] In the physicochemical treatment, cyanide removal agent B is composed of activated carbon, polyferric sulfate, copper sulfate, cerium oxide, ethylene glycol, and dicyandiamide-formaldehyde condensate. The mass ratio of the six substances is activated carbon: polyferric sulfate: copper sulfate: cerium oxide: ethylene glycol: dicyandiamide-formaldehyde condensate = 2:3:1:2:0.2:1.5; 7 ppm of polyacrylamide anion is added.

[0048] Example 2

[0049] The cyanide content in the wastewater of a coking plant in Lüliang, Shanxi Province was 1200 mg / L. After pretreatment with 3500 ppm of cyanide removal agent A, the cyanide content in the effluent reached 701 mg / L. After 4 hours of oxidation and photolysis treatment, the cyanide content in the effluent reached 521 mg / L. After physicochemical treatment with 14000 ppm of cyanide removal agent B, the cyanide content in the effluent decreased to 55 mg / L. After 40 hours of biological treatment, the cyanide content in the effluent decreased to 12 mg / L. After resin treatment at a flow rate of 2 BV / h, the cyanide content decreased to 4.3 mg / L. After 1 hour of electrolysis at 10 V and 0.4 A, the cyanide content in the effluent reached 0.14 mg / L.

[0050] In this embodiment, the cyanide removal agent A added during pretreatment is composed of ferrous chloride, polyaluminum chloride and zinc chloride, and the ratio between each component is calculated according to the molar ratio of ferrous:aluminum:zinc = 5:3:2. After adding the cyanide removal agent, the mixture is stirred for 40 minutes, 10 ppm of polyacrylamide anion is added, and the mixture is stirred for another 15 minutes. After 4 hours of settling, the water is discharged.

[0051] The oxidation + photolysis steps involve a catalyst prepared with a titanium dioxide to silicon dioxide mass ratio of 1:1.5, with an addition amount of 2000 mg / L, and irradiation with 20,000 lx ultraviolet light.

[0052] In the physicochemical treatment, cyanide removal agent B is composed of activated carbon, polyferric sulfate, copper sulfate, cerium oxide, ethylene glycol, and dicyandiamide-formaldehyde condensate. The mass ratio of the six substances is activated carbon: polyferric sulfate: copper sulfate: cerium oxide: ethylene glycol: dicyandiamide-formaldehyde condensate = 3:2:2:1:0.5:1; 4 ppm of polyacrylamide anion is added.

[0053] Example 3

[0054] In another coking plant in Lüliang, Shanxi, the cyanide content in the wastewater was 1150 mg / L. After pretreatment with 3000 ppm of cyanide removal agent A, the cyanide content in the effluent reached 690 mg / L. After 4 hours of oxidation and photolysis treatment, the cyanide content in the effluent reached 510 mg / L. After physicochemical treatment with 14500 ppm of cyanide removal agent B, the cyanide content in the effluent decreased to 60 mg / L. After 40 hours of biological treatment, the cyanide content in the effluent decreased to 13 mg / L. After resin treatment at a flow rate of 2 BV / h, the cyanide content decreased to 4.1 mg / L. After 1 hour of electrolysis at 10 V and 0.4 A, the cyanide content in the effluent reached 0.15 mg / L.

[0055] In this embodiment, the cyanide removal agent A added during pretreatment consists of ferrous chloride, polyaluminum chloride and zinc nitrate, and the ratio between the components is calculated according to the molar ratio of ferrous chloride:aluminum:zinc = 5:3:2. After adding the cyanide removal agent, the mixture is stirred for 40 minutes, 8 ppm of polyacrylamide anion is added, and the mixture is stirred for another 15 minutes. After 4 hours of settling, the water is discharged.

[0056] The oxidation + photolysis steps involved a catalyst prepared with a titanium dioxide to silicon dioxide mass ratio of 1:1.5, with an addition amount of 2000 mg / L, and irradiation with 30,000 lx ultraviolet light.

[0057] In the physicochemical treatment, cyanide removal agent B is composed of activated carbon, polyferric sulfate, copper sulfate, cerium oxide, ethylene glycol, and dicyandiamide-formaldehyde condensate. The mass ratio of the six substances is activated carbon: polyferric sulfate: copper sulfate: cerium oxide: ethylene glycol: dicyandiamide-formaldehyde condensate = 2.5:2:2:1:0.5:1; 5 ppm of polyacrylamide anion is added.

[0058] Comparative Example 1

[0059] Comparative Example 1 is a comparative experiment of Example 1. The difference is that the treatment steps in Comparative Example 1 are pretreatment, biochemical treatment, oxidation plus photolysis treatment, physicochemical and physical treatment, resin treatment and electrolysis treatment, that is, the biochemical treatment is brought forward. Other specific parameters are the same as in Example 1. The results show that the coking wastewater in Comparative Example 1 after only pretreatment has a high cyanide content, which exceeds the load limit of cyanide removal bacteria in the biochemical treatment. The biochemical treatment stage cannot proceed smoothly, resulting in a very small reduction in the cyanide content of the coking wastewater during the biochemical treatment process. The final effluent cyanide content is 6.5 mg / L, which is still relatively high.

[0060] In summary, the high-cyanide coking wastewater treatment steps of this invention are specifically defined by combining the characteristics of each treatment step and the physicochemical properties of the coking wastewater. Only by treating the wastewater according to the steps of this invention can a significant reduction in cyanide be achieved while ensuring the normal operation of each treatment system, and the functions of each treatment system can be maximized.

[0061] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for treating high-cyanide coking wastewater, characterized in that, The method involves sequentially treating high-cyanide coking wastewater through pretreatment, oxidation and photolysis, physicochemical treatment, biochemical treatment, resin treatment, and electrolysis to obtain treated water with a cyanide content of less than 0.2 mg / L. The pretreatment involves adding cyanide removal agent A to the high-cyanide coking wastewater and stirring, then adding anionic polyacrylamide, stirring, and allowing it to settle before effluent discharge. The oxidation and photolysis treatment involves introducing ozone into the pretreated effluent for aeration and stirring, then adding a catalyst, and finally irradiating the effluent with sunlight or ultraviolet light for a predetermined time before effluent is discharged. The physical and chemical treatment involves adding cyanide removal agent B to the effluent after oxidation and photolysis treatment, stirring, adding polyacrylamide anion, and then effluent after a predetermined treatment time. The biochemical treatment involves first inoculating the water tank with acclimatized cyanide-removing bacteria and adding a carbon source. When the COD in the water tank is degraded to below 500, the effluent after physical and chemical treatment is introduced. After the predetermined treatment time, the water is stirred and allowed to stand. The supernatant is then taken for later use. The resin treatment involves transferring the supernatant after biochemical treatment into an ion-exchange resin or an adsorption resin for further treatment. The electrolysis process involves treating the resin effluent using a carbon rod. In the pretreatment, cyanide removal agent A is composed of ferrous sulfate, polyaluminum chloride, and zinc salt. The ferrous sulfate is either ferrous sulfate or ferrous chloride, and the zinc salt is any one of zinc sulfate, zinc chloride, or zinc nitrate. The molar ratio of ferrous sulfate to polyaluminum chloride to zinc salt is 5:3:

2. The mass ratio of cyanide in the high-cyanide coking wastewater to cyanide removal agent A is 1:30-40, and the amount of polyacrylamide anion added is 5-10 ppm. In the physicochemical treatment, cyanide removal agent B is composed of activated carbon, polyferric sulfate, copper sulfate, cerium oxide, ethylene glycol, and dicyandiamide-formaldehyde condensate in a mass ratio of 2-3:2-3:1-2:1-2:0.2-0.5:1-1.5; after oxidation and photolysis treatment, the mass ratio of cyanide in the effluent to cyanide removal agent B is 1:30-50; the amount of polyacrylamide anion added is 4-7 ppm.

2. The method for treating high-cyanide coking wastewater according to claim 1, characterized in that, In the oxidation and photolysis treatment, the catalyst is prepared according to the mass ratio of titanium dioxide to silicon dioxide of 1:1-1.

5. The water is irradiated with sunlight ≥90,000 lx and ultraviolet light ≥20,000 lx for ≥3.5 hours.

3. The method for treating high-cyanide coking wastewater according to claim 1, characterized in that, In the biological treatment, the inoculation amount of cyanide-removing bacteria is 10-20% of the wastewater volume in the pool; the carbon source is glucose, and the addition amount is 1000ppm; the environmental conditions of the pool are: temperature 32℃, pH=9, aeration rate ≥2.5L / min; when the effluent after physicochemical treatment is introduced into the biological treatment pool, on the first day, a volume less than or equal to 20% of the total volume of cyanide-removing bacteria is introduced, and from the second day onwards, the daily increase in water volume is no more than 1.1 times the previous day's water volume, until the normal influent volume is reached; the biological treatment time is ≥30h, and the water is allowed to stand for more than 3 hours.

4. The method for treating high-cyanide coking wastewater according to claim 1, characterized in that, During resin processing, the resin particle size is 0.4-0.7 mm, and the flow rate is controlled at 2-3 Bv / h.

5. The method for treating high-cyanide coking wastewater according to claim 1, characterized in that, In the electrolysis process, multiple sets of carbon rods are selected as the anode and cathode, with a distance of 20-30 cm between the carbon rods, a current of 0.3-0.5A, a voltage control of 8-10V, and water is discharged after the electrolysis time exceeds 50 minutes.

6. A method for treating high-cyanide coking wastewater according to any one of claims 1-5, characterized in that, The cyanide content in high-cyanide coking wastewater is ≥1000 mg / L.