Method for treating high-concentration cyanide-containing wastewater at low cost

Abstract

The invention discloses a low-cost method for treating high-concentration cyanide-containing wastewater, which comprises the following steps: (1) feeding neutral high-concentration cyanide-containing wastewater on a production line into a primary reaction tank through a first wastewater delivery pump, and preparing and quantitatively adding an oxidant on line by adopting a special cyanide breaking device; (2) overflowing the reacted wastewater into a secondary reaction tank, and continuing the reaction; (3) overflowing the wastewater which completely reaches the standard after the cyanogen breaking reaction into the regulating tank, and adding NaOH; and (4) conveying the wastewater to a wastewater comprehensive treatment plant through the second wastewater conveying pump. According to the method disclosed by the invention, the oxidizing agent is prepared by adopting a special cyanide breaking device, the strong oxidizing property of the oxidizing agent is utilized, the cyanide breaking reaction is performed on a high-concentration cyanide-containing wastewater treatment device, and the wastewater can stably reach the standard without adjusting the pH value of the wastewater on the basis of not changing the original treatment device.

Description

Technical Field

[0001] The invention relates to the field of sewage treatment, and in particular to a method for treating high-concentration cyanide-containing wastewater at a low cost. Background Art

[0002] In the national economic construction, cyanide wastewater mainly comes from many industrial productions. Since cyanide wastewater is a highly toxic inorganic wastewater, it has a strong toxic effect on both organisms and the environment. It is a wastewater that the state must treat and must not be discharged arbitrarily or in violation of standards. Therefore, it is of great practical and social significance to treat cyanide wastewater and discharge it in compliance with standards.

[0003] With the development of the economy, the amount of wastewater has been increasing, and the cyanide content has been increasing. People have been conducting research on the treatment of cyanide-containing wastewater. So far, the most widely used and common method is the hypochlorite oxidation method, which is relatively mature, stable and easy to control. However, hypochlorite has low effective chlorine content, short validity period, is not easy to store, has a large dosage, a large amount of slag, a large transportation volume, a slightly low cyanide breaking ability, poor impact resistance, and a high treatment cost; especially for the treatment of high-concentration cyanide-containing wastewater with a cyanide content of 1000-3000 mg / L, the wastewater treatment has always been unstable, and the treatment cost is as high as 1,000 yuan / t, which is a headache for users. Nowadays, the treatment of this high-concentration cyanide-containing wastewater only uses this simple treatment technology method, which is difficult to meet the stable standard and low-cost operation of the wastewater treatment. However, there is no better treatment method to replace it, so we have been looking for a better treatment process technology. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for treating high-concentration cyanide-containing wastewater with low cost and simple operation. The method adopts a special device for breaking cyanide to prepare an oxidant, and uses its strong oxidizing property to carry out a cyanide breaking reaction on a high-concentration cyanide-containing wastewater treatment device. The method can be carried out without changing the original treatment device, and finally the wastewater can be stably up to standard.

[0005] The method for treating high-concentration cyanide-containing wastewater at low cost of the present invention comprises the following steps:

[0006] (1) The neutral high-concentration cyanide-containing wastewater on the production line is delivered to the primary reaction tank through the first wastewater delivery pump, and an oxidant is prepared online and quantitatively added using a special device for breaking cyanide. Since the oxidant solution produced by the reaction of the special device for breaking cyanide contains very little acid, it is not necessary to add NaOH to adjust the pH value, and the cyanide breaking reaction can be well guaranteed;

[0007] (2) overflowing the wastewater after the reaction in step (1) to a secondary reaction tank, and continuing the reaction, so that the cyanide breaking of the wastewater is completely stable and meets the standard;

[0008] (3) overflowing the wastewater that has completely met the standards after the cyanide destruction reaction in step (2) to the regulating tank, adding NaOH to increase the pH value, thereby laying a foundation for subsequent heavy metal treatment;

[0009] (4) The wastewater obtained from the cyanide destruction reaction in step (3) that completely meets the standards is then pumped to a comprehensive wastewater treatment plant via the second wastewater delivery pump.

[0010] The low-cost method for treating high-concentration cyanide-containing wastewater of the present invention comprises the following steps: the cyanide content in the neutral high-concentration cyanide-containing wastewater in step (1) is 1000-3000 mg / L; the preparation capacity of the special cyanide-breaking device is 20000 g / h (i.e., 20000 g of oxidant can be prepared per hour), and a high-purity and high-concentration chlorine dioxide oxidant is prepared.

[0011] The low-cost method for treating high-concentration cyanide-containing wastewater of the present invention comprises the following steps: in the process of preparing an oxidant by the special cyanide-breaking device, the raw material is prepared by a mixed solution of sulfuric acid with a concentration of 68-72% and a cyanide-breaking agent with a concentration of 43-46%, and the feed volume ratio is solid solution: acid=1:0.50-0.54, wherein the solid solution is the mixed solution of the cyanide-breaking agent.

[0012] The low-cost method for treating high-concentration cyanide-containing wastewater of the present invention comprises the following reaction conditions during the preparation of the oxidant: temperature: 68-73° C., negative pressure: -6-6.6 KPa.

[0013] The low-cost method for treating high-concentration cyanide-containing wastewater of the present invention comprises the following steps: according to the cyanide content in the wastewater analyzed by chemical analysis, the operation time of the cyanide-breaking device is controlled to be 0.5 to 1.5 hours, so as to quantitatively control the addition of oxidant.

[0014] The low-cost method for treating high-concentration cyanide-containing wastewater of the present invention comprises the following steps: in step (3), after the cyanide-breaking reaction of the neutral wastewater reaches the standard, the pH value decreases, and the pH value of the wastewater is increased to 5 to control the dosage of NaOH, wherein the NaOH is a 5% NaOH solution.

[0015] The low-cost method for treating high-concentration cyanide-containing wastewater of the present invention comprises the following steps: the reaction time of the primary reaction tank and the secondary reaction tank are both 30 minutes; and the primary reaction tank, the secondary reaction tank and the regulating tank all use mechanical agitators.

[0016] A special device used in the method for treating high-concentration cyanide-containing wastewater at low cost according to the present invention comprises a first wastewater delivery pump, a primary reaction tank, a secondary reaction tank, a regulating tank and a second wastewater delivery pump which are connected in sequence, wherein the primary reaction tank is connected to a special device for breaking cyanide through a pipeline, and the regulating tank is connected to a NaOH solution storage tank through a pipeline.

[0017] The special device of the present invention, wherein:

[0018] The primary reaction tank is provided with a high-concentration cyanide-containing wastewater inlet, an oxidant addition port, and a wastewater overflow port; the high-concentration cyanide-containing wastewater inlet is connected to the first wastewater delivery pump through a pipeline, the oxidant addition port is connected to the cyanide-breaking device through a pipeline, and the wastewater overflow port is connected to the primary reaction tank and the secondary reaction tank;

[0019] The regulating tank is provided with a wastewater inlet, a NaOH solution addition port, and a wastewater outlet; the secondary reaction tank is provided with a wastewater outlet connected to the wastewater inlet of the regulating tank; the NaOH solution addition port is connected to the NaOH solution storage tank through a pipeline; the wastewater outlet is connected to the second wastewater delivery pump through a pipeline.

[0020] The special device described in the present invention is characterized in that mechanical stirrers are provided in the primary reaction tank, the secondary reaction tank and the regulating tank.

[0021] The low-cost method for treating high-concentration cyanide-containing wastewater of the present invention is different from the prior art in that:

[0022] The present invention is a new method for treating high-concentration cyanide-containing wastewater at low cost, which makes up for the blank of the current high-concentration cyanide-containing wastewater treatment method and changes the idea and method of the original oxidation method. Since the cyanide content of the wastewater can be as high as about 3000 mg / L, in the original oxidation method, the oxidizing property of hypochlorite itself is not very strong and the impact resistance is poor. It is difficult to treat the wastewater to meet the standard. In addition, the cyanide content of the wastewater fluctuates between 1000 and 3000 mg / L, which makes it more difficult to achieve the purpose of stable standard. If the oxidant is added excessively in order to stably meet the standard, the treatment cost of the wastewater will inevitably increase, which can be as high as about 1000 yuan / t. In view of this problem, enterprises have been seeking a more ideal treatment technology method, but have never found it. The research of the present invention is key to adopt a new type of special device method for breaking cyanide, prepare an oxidant, and use its strong oxidizing property to completely break the cyanide in the wastewater. At the same time, according to the fluctuation of cyanide content in wastewater, the cyanide content in wastewater is analyzed based on chemical analysis. Under the premise of ensuring sufficient dosage, the operation time of the special cyanide breaking device is controlled to vary from 0.5 to 1.5 hours, and oxidant is added quantitatively, which provides a fundamental guarantee for the treatment of high-concentration cyanide wastewater to meet the standards and ensures that the wastewater treatment meets the standards stably.

[0023] The most important thing about the innovative method for treating high-concentration cyanide-containing wastewater at low cost of the present invention is that a special device for breaking cyanide is used, which changes the conventional ideas and methods for oxidation treatment of cyanide-containing wastewater. Before the special device for breaking cyanide was developed, a high-purity generator was used to break cyanide. Since the oxidant solution is strongly acidic and in large quantity, and the breaking of cyanide is required to be carried out under alkaline conditions for the best effect, a large amount of NaOH needs to be added before breaking cyanide to adjust the pH value of the neutral wastewater to alkaline to ensure that the acidic solution brought by the oxidant can be neutralized. In this way, it is bound to increase a certain cost for the treatment of cyanide-containing wastewater, making the treatment cost very high, which is a very troublesome problem for users. The special cyanide breaking device adopted by the present invention uses a cyanide breaking agent mixed solution, uses less acid, and the prepared oxidant solution has less acid content. This is an oxidant preparation technology currently not available in China. Therefore, it is not necessary to add NaOH to adjust the pH value of cyanide-containing wastewater, and the oxidant solution can directly break the cyanide in neutral wastewater until it is completely stable and meets the standard. In this way, the comprehensive treatment cost of wastewater can be reduced from the original 1,000 yuan / t to <760 yuan / t, and then to <500 yuan / t. This is a very obvious and considerable effect, creating a precedent, which can only be achieved by the special cyanide breaking device.

[0024] The invention utilizes a new treatment process technology and adopts a special cyanide-breaking device to treat high-concentration cyanide-containing wastewater at a low cost, which not only reduces manpower and material resources, has a simple process and convenient operation, but also can utilize the original wastewater treatment device, effectively saving construction investment, and finding a new technical method for enterprises, actively promoting the low-cost and stable treatment of high-concentration cyanide-containing wastewater in enterprises that meets the standards, and plays a positive role in the in-depth implementation of environmental protection.

[0025] The low-cost method for treating high-concentration cyanide-containing wastewater of the present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a schematic diagram of the structure of a special device for the method of treating high-concentration cyanide-containing wastewater at low cost according to the present invention. DETAILED DESCRIPTION

[0027] Example 1

[0028] A method for treating high-concentration cyanide-containing wastewater at low cost, comprising online preparation of an oxidant using a special cyanide-breaking device, wherein the raw material is prepared from a mixed solution of sulfuric acid with a concentration of 68-72% and a cyanide-breaking agent with a concentration of 43-46%, and the feed volume ratio is solid solution: acid = 1: 0.50-0.54, wherein the solid solution is a cyanide-breaking agent mixed solution. The reaction conditions during the preparation of the oxidant are: temperature: 68-73°C, negative pressure: -6-6.6KPa.

[0029] The cyanide-breaking device and cyanide-breaking agent used in the present invention are both commercially available products purchased from Shenzhen Zhongke Outaihua Environmental Protection Technology Co., Ltd., the company website: http: / / www.zkoth.com.

[0030] Example 2

[0031] like Figure 1 As shown, a special device for treating high-concentration cyanide-containing wastewater at a low cost comprises a first wastewater delivery pump 1, a primary reaction tank 4, a secondary reaction tank 6, an adjusting tank 7 and a second wastewater delivery pump 8 connected in sequence, wherein the primary reaction tank 4 is connected to the special device for breaking cyanide 2 through a pipeline, and the adjusting tank 7 is connected to the NaOH solution storage tank 3 through a pipeline.

[0032] The primary reaction tank 4 is provided with a high-concentration cyanide-containing wastewater inlet 401, an oxidant addition port 402, and a wastewater overflow port 403; the high-concentration cyanide-containing wastewater inlet 401 is connected to the first wastewater delivery pump 1 through a pipeline, the oxidant addition port 402 is connected to the cyanide-breaking device 2 through a pipeline, and the wastewater overflow port 403 connects the primary reaction tank 4 and the secondary reaction tank 6;

[0033] The regulating tank 7 is provided with a wastewater inlet 701, a NaOH solution addition port 702, and a wastewater outlet 703; the secondary reaction tank 6 is provided with a wastewater outlet 601 connected to the wastewater inlet 701; the NaOH solution addition port 702 is connected to the NaOH solution storage tank 3 through a pipeline; the wastewater outlet 703 is connected to the second wastewater delivery pump 8 through a pipeline. Mechanical stirrers 5 are provided in the primary reaction tank 4, the secondary reaction tank 6, and the regulating tank 7.

[0034] Example 3

[0035] A method for treating high-concentration cyanide-containing wastewater at low cost, using the device of Example 2 for treatment, specifically comprising the following steps:

[0036] (1) The wastewater with a cyanide content of 1060 mg / L on the production line is fed into a primary reaction tank 4 through a wastewater delivery pump 1, and an oxidant is prepared using a 20000 g / h cyanide breaking device 2 (the oxidant preparation method adopts the scheme of Example 1, and 20000 g / h refers to the production capacity of the equipment, that is, 20000 grams per hour). According to the cyanide content in the wastewater, the operation time of the cyanide breaking device 2 is controlled to be 0.55 h, and the oxidant is quantitatively added. It is not necessary to add NaOH to the wastewater to adjust the pH value, and the cyanide breaking reaction is directly carried out, and the cyanide breaking reaction is stirred under a stirrer 5 for 30 min.

[0037] (2) The wastewater after the reaction in step (1) overflows into the secondary reaction tank 6, is stirred under the stirrer 5, and continues to break the cyanide, and the reaction time is 30 minutes, so that the cyanide breaking of the wastewater is completely stable and meets the standards.

[0038] (3) The wastewater that has completely met the standards after the cyanide breaking reaction in step (2) overflows into the regulating tank 7, and under the stirring of the stirrer 5, a 5% NaOH solution is added to adjust the pH value of the wastewater. The pH value of the wastewater after the cyanide breaking reaction is 3.1, and then increased to a pH value of 5.1 to control the dosage of the 5% NaOH solution, thereby laying a foundation for the subsequent heavy metal treatment.

[0039] (4) The wastewater from the cyanide destruction reaction in step (3) that has completely met the standards is delivered to a comprehensive wastewater treatment plant via a wastewater delivery pump 8.

[0040] In the present invention, the oxidant is prepared online and quantitatively added, and the preparation and addition process is carried out together with the wastewater treatment process.

[0041] The high-concentration cyanide-containing wastewater after the above treatment was sampled and statistically analyzed: cyanide content: 0.39ppm, cyanide removal rate: 100%, and comprehensive treatment cost: 486 yuan / t.

[0042] Example 4

[0043] The difference from Example 3 is that: in step (1), the cyanide content on the production line is 2040 mg / L of wastewater, and the operation time of the cyanide-breaking device is controlled to be 1.0 h to quantitatively add the oxidant. In step (3), the pH value of the wastewater after the cyanide-breaking reaction is 3.3, and then increased to pH 5.2 to control the dosage of 5% NaOH solution. The rest is the same as in Example 3.

[0044] The high-concentration cyanide-containing wastewater after the above treatment was sampled and statistically analyzed: cyanide content: 0.44ppm, cyanide removal rate: 100%, and comprehensive treatment cost: 488 yuan / t.

[0045] Example 5

[0046] The difference from Example 3 is that in step (1), the cyanide content on the production line is 2620 mg / L of wastewater, and the operation time of the cyanide-breaking device is controlled to be 1.3 h to quantitatively add the oxidant. In step (3), the pH value of the wastewater after the cyanide-breaking reaction is 3.0, and then increased to pH 5.1 to control the dosage of 5% NaOH solution. The rest is the same as in Example 3.

[0047] The high-concentration cyanide-containing wastewater after the above treatment was sampled and statistically analyzed: cyanide content: 0.45ppm, cyanide removal rate: 100%, and comprehensive treatment cost: 491 yuan / t.

[0048] Example 6

[0049] The difference from Example 3 is that in step (1), the cyanide content on the production line is 2850 mg / L of wastewater, and the operation time of the cyanide-breaking device is controlled to be 1.4 hours to quantitatively add the oxidant. In step (3), the pH value of the wastewater after the cyanide-breaking reaction is 3.1, and then increased to pH 5.3 to control the dosage of 5% NaOH solution. The rest is the same as in Example 3.

[0050] The high-concentration cyanide-containing wastewater after the above treatment was sampled and statistically analyzed: cyanide content: 0.47ppm, cyanide removal rate: 100%, and comprehensive treatment cost: 494 yuan / t.

[0051] Example 7

[0052] The difference from Example 3 is that: in step (1), the cyanide content on the production line is 2980 mg / L of wastewater, and the operation time of the cyanide-breaking device is controlled to be 1.5 hours to quantitatively add the oxidant. In step (3), the pH value of the wastewater after the cyanide-breaking reaction is 2.9, and then increased to pH 5.2 to control the dosage of 5% NaOH solution. The rest is the same as in Example 3.

[0053] The high-concentration cyanide-containing wastewater after the above treatment was sampled and statistically analyzed: cyanide content: 0.48ppm, cyanide removal rate: 100%, and comprehensive treatment cost: 495 yuan / t.

[0054] Oxidant comparison ratio:

[0055] 1. The oxidant uses traditional sodium hypochlorite:

[0056] In the method of the present invention, other conditions remain unchanged, and the oxidant is replaced with sodium hypochlorite. Due to the low content of sodium hypochlorite solution, for high-concentration cyanide-containing wastewater, a large amount of sodium hypochlorite solution needs to be added to the primary reaction tank for cyanide breaking reaction. In addition, sodium hypochlorite has low oxidizability and is unstable, so it needs to be added in excess, and the reaction time will be increased to about 40 minutes, so the wastewater treatment cost will be greatly increased to about 1,000 yuan / t.

[0057] In addition, the cyanide content of high-concentration cyanide wastewater fluctuates between 1000 and 3000 mg / L. Since sodium hypochlorite has poor impact resistance when its oxidizing property is not strong, the cyanide content of the wastewater is very unstable.

[0058] After the above treatment, the high-concentration cyanide-containing wastewater was sampled and statistically tested, with the cyanide content ranging from 0.35 to 0.82 ppm, and the cyanide removal rate reaching the standard of 96% to 100%. The treatment effect was very unstable, and the comprehensive treatment cost ranged from 1,000 to 1,035 yuan / t.

[0059] 2. Oxidant: A high-purity generator in the prior art is used to prepare a high-purity chlorine dioxide oxidant. The differences between the preparation process and the present invention are as follows:

[0060]

[0061] Other unexplained conditions are the same, and the unexplained parameters and methods used in the wastewater treatment process are also the same. When a cyanide-breaking device is used, the solid solution here is a cyanide-breaking agent mixed solution.

[0062] The cyanide-breaking agent is a product exclusively sold for the supporting cyanide-breaking device. The components of the solid solution of the high-purity generator are different, which is the most critical. Only when the components are different, the different effects of the present invention will be produced. At the same time, the acid dosage of the cyanide-breaking device is reduced by more than 60%, the water is also reduced accordingly, the concentration of the solid mixed solution is also increased, and the water is also reduced by 40%, so the product oxidant is a high-concentration solution, and the negative pressure requirement is high.

[0063] From the perspective of the preparation process of the oxidant only, the present invention has the following advantages:

[0064] 1. Oxidant preparation cost:

[0065] The dosage of acid in the cyanide-breaking device was reduced by more than 60%, so the preparation cost of the oxidant was reduced by 32.83%.

[0066] 2. Raw material conversion rate:

[0067] The solid mixed solution increased the concentration, reduced 40% of water, and after reacting with the acid, the raw material conversion rate increased by 3.16%.

[0068] 3. Residual acid in waste liquid:

[0069] The residual acid content in the waste liquid after the reaction decreased by 66.4%, greatly saving the cost of acid-base neutralization.

[0070] Comparison of the application of two oxidants:

[0071] Comparison of the method and effect of using the oxidant prepared by the high-purity generator and the oxidant prepared by the present invention for wastewater treatment:

[0072] When using oxidants prepared by high-purity generators to treat wastewater with a cyanide content of 1000-3000 mg / L, in addition to the differences in oxidant preparation, there are also the following differences in application:

[0073] When using the oxidant prepared by a high-purity generator, 5% NaOH solution needs to be added to the primary reaction tank and the secondary reaction tank respectively. The dosage is controlled according to the wastewater pH value of 5 to 7, and the reaction time is 30 to 40 minutes.

[0074] The high-concentration cyanide-containing wastewater treated with the oxidant prepared by the above high-purity generator has been sampled and statistically analyzed: cyanide content: <0.5ppm, cyanide removal rate: 100%, and comprehensive treatment cost: 690-760 yuan / t.

[0075] When the oxidant of the present invention is used for wastewater treatment, no alkali needs to be added to the reaction tank, which greatly reduces the treatment cost. The high-concentration cyanide-containing wastewater treated by the oxidant of the present invention is sampled and statistically analyzed: the results are shown in Examples 3 to 7.

[0076] The embodiments described above are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for treating high-concentration cyanide-containing wastewater at low cost, characterized in that: The steps include: (1) The neutral high-concentration cyanide-containing wastewater on the production line is sent to the primary reaction tank through the first wastewater delivery pump, and an oxidant is prepared online using a special cyanide-breaking device and quantitatively added, without the need to add NaOH to adjust the pH value; (2) overflowing the wastewater after the reaction in step (1) to a secondary reaction tank, and continuing the reaction to ensure that the cyanide destruction of the wastewater is completely stable and meets the standard; (3) overflowing the wastewater that has completely met the standards after the cyanide destruction reaction in step (2) to the regulating tank, adding NaOH to increase the pH value, thereby laying a foundation for subsequent heavy metal treatment; (4) The wastewater obtained from the cyanide destruction reaction in step (3) and completely meeting the standards is then pumped to a comprehensive wastewater treatment plant via the second wastewater delivery pump.

2. The method for treating high-concentration cyanide-containing wastewater at low cost according to claim 1, characterized in that: The cyanide content in the neutral high-concentration cyanide-containing wastewater in step (1) is 1000-3000 mg / L; the preparation capacity of the special cyanide-breaking device is 20000 g / h, and a high-purity and high-concentration chlorine dioxide oxidant is prepared.

3. The method for treating high-concentration cyanide-containing wastewater at low cost according to claim 2, characterized in that: In the process of preparing the oxidant by the special device for breaking cyanide, the raw material is prepared from a mixed solution of sulfuric acid with a concentration of 68-72% and a cyanide-breaking agent with a concentration of 43-46%, and the feed volume ratio is solid solution: acid = 1: 0.50-0.54, wherein the solid solution is the mixed solution of the cyanide-breaking agent.

4. The method for treating high-concentration cyanide-containing wastewater at low cost according to claim 2, characterized in that: The reaction conditions during the preparation of the oxidant are: temperature: 68-73° C., negative pressure: -6-6.6 KPa.

5. The method for treating high-concentration cyanide-containing wastewater at low cost according to claim 1, characterized in that: According to the cyanide content in the wastewater, the operation time of the cyanide-breaking device is controlled to be 0.5 to 1.5 hours to quantitatively control the addition of the oxidant.

6. The method for treating high-concentration cyanide-containing wastewater at low cost according to claim 1, characterized in that: In step (3), after the cyanide destruction reaction of the neutral wastewater reaches the standard, the pH value decreases, and the pH value of the wastewater needs to be increased to 5 to control the dosage of NaOH, wherein the NaOH is a 5% NaOH solution.

7. The method for treating high-concentration cyanide-containing wastewater at low cost according to claim 6, characterized in that: The reaction time of the primary reaction tank and the secondary reaction tank is 30 minutes; the primary reaction tank, the secondary reaction tank and the regulating tank all use mechanical stirrers.

8. A special device used in the method for treating high-concentration cyanide-containing wastewater at low cost according to claim 1, characterized in that: The invention comprises a first wastewater delivery pump (1), a primary reaction tank (4), a secondary reaction tank (6), an adjusting tank (7) and a second wastewater delivery pump (8) which are connected in sequence, wherein the primary reaction tank (4) is connected to a cyanide-destroying device (2) via a pipeline, and the adjusting tank (7) is connected to a NaOH solution storage tank (3) via a pipeline.

9. The special device according to claim 8, characterized in that: The primary reaction tank (4) is provided with a high-concentration cyanide-containing wastewater inlet (401), an oxidant addition port (402), and a wastewater overflow port (403); the high-concentration cyanide-containing wastewater inlet (401) is connected to the first wastewater delivery pump (1) through a pipeline, the oxidant addition port (402) is connected to the cyanide-destroying device (2) through a pipeline, and the wastewater overflow port (403) enables the primary reaction tank (4) and the secondary reaction tank (6) to communicate with each other; The regulating tank (7) is provided with a wastewater inlet (701), a NaOH solution addition port (702), and a wastewater outlet (703); the secondary reaction tank (6) is provided with a wastewater outlet (601) connected to the wastewater inlet (701); the NaOH solution addition port (702) is connected to the NaOH solution storage tank (3) via a pipeline; and the wastewater outlet (703) is connected to the second wastewater delivery pump (8) via a pipeline.

10. The special device according to claim 9, characterized in that: A mechanical stirrer (5) is provided in the primary reaction tank (4), the secondary reaction tank (6) and the regulating tank (7).

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