System for treating middle-low concentration cyanide-containing wastewater difficult to treat

Abstract

The utility model belongs to the technical field of environmental protection technology and gold mine cyanide-containing wastewater treatment, and particularly relates to a system for treating middle-low concentration cyanide-containing wastewater difficult to treat. Wherein the tops of the first-stage oxidation stirring tank, the second-stage oxidation stirring tank, the acid-base adjusting tank, the reduction precipitation tank, the first-stage mixed liquid buffer tank and the first-stage filtrate buffer tank are provided with reaction gas collecting pipes, the tops of the first-stage oxidation stirring tank and the second-stage oxidation stirring tank are respectively provided with an oxidation agent feeding pipe, and the top of the acid-base adjusting tank is provided with an acid-base agent feeding pipe; a reduction precipitant feeding pipe is arranged at the top of the reduction precipitation tank, and a neutralizing agent feeding pipe is arranged at the top of the neutralizing tank; every two adjacent stages of the first-stage oxidation stirring tank, the second-stage oxidation stirring tank, the acid-base adjusting tank, the reduction precipitation tank and the first-stage mixed liquid buffer tank are communicated with each other, the first-stage mixed liquid buffer tank is communicated with the first-stage filtering device, and the first-stage filtering device is communicated with the first-stage filtrate buffer tank; every two adjacent stages of the first-stage filtrate buffer tank, the neutralizing tank and the neutralizing mixed liquor buffer tank are communicated with each other, the neutralizing mixed liquor buffer tank is communicated with the mixed liquor filtering device, and the mixed liquor filtering device is communicated with the second-stage filtrate buffer tank; the device is simple in process flow, stable in operation and good in treatment effect.

Description

Technical Field

[0001] The utility model belongs to the technical fields of environmental protection technology and cyanide-containing wastewater treatment technology in gold mines, and particularly relates to a treatment system for medium and low concentration cyanide-containing wastewater which is difficult to treat. Background Art

[0002] With the continuous reduction of easily treatable gold ore resources, refractory gold ore resources have become the main raw material source for gold industry production. To improve the recovery rate of gold in refractory gold ore, generally, the original ore is subjected to biological oxidation, autoclave oxidation, roasting pretreatment. After removing some impurities, the gold grade of the gold concentrate is generally relatively high. When cyanidation gold extraction is carried out, the dosage of sodium cyanide increases, and the contents of cyanide and other heavy metal pollutants in the cyanide tailings slurry and gold extraction wastewater produced are also higher than those in the direct cyanidation of the original ore, and the treatment of the corresponding tailings slurry and cyanide-containing wastewater is more difficult.

[0003] At present, most of the tailings slurry after gold extraction from gold concentrate is treated by pressure filtration and slurry adjustment for harmless treatment, and the adjusted slurry is recycled. Due to the continuous internal circulation of the adjusted slurry, impurities accumulate continuously, affecting the process effect. For this part of cyanide-containing wastewater, its cyanide concentration is higher than that of general cyanide-containing wastewater, and there are also difficult-to-treat pollutants such as heavy metals such as copper, lead, zinc, arsenic and their complexes with cyanide, which is more difficult to treat than general cyanide-containing wastewater.

[0004] To sum up, medium and low concentration cyanide-containing wastewater and tailings pond leachate are generated in the treatment process of cyanide tailings slurry produced by the cyanidation process of gold concentrate. The content of difficult-to-treat cyanide in these waste liquids is high, and heavy metals and their complexes coexist. However, there is currently no applicable device that can achieve the standard purification treatment of cyanide-containing wastewater. Summary of the Invention

[0005] In order to overcome the above problems, the utility model provides a treatment system for medium and low concentration cyanide-containing wastewater which is difficult to treat. Aiming at the complex cyanide and heavy metals that are difficult to treat in the cyanide-containing wastewater, acidification reduction coprecipitation is realized through a multi-stage tank body to remove cyanide that is difficult to oxidize and decompose. The mixed liquid after precipitation is filtered by a pressure filtration device, and the tail liquid can reach the purpose of wastewater purification after neutralization; the process flow of the utility model is simple, the operation is stable, and the treatment effect is good.

[0006] A treatment system for difficult-to-treat cyanide-containing wastewater with medium and low concentrations, comprising a first-stage oxidation stirring tank 1, a second-stage oxidation stirring tank 2, an acid-base adjustment tank 3, a reduction precipitation tank 4, a first-stage mixed liquid buffer tank 5, a first-stage filtration device 7, a first-stage filtrate buffer tank 8, a neutralization tank 9, a neutralization mixed liquid buffer tank 10, a neutralization mixed liquid filtration device 12 and a second-stage filtrate buffer tank 13; wherein the first-stage oxidation stirring tank 1, the second-stage oxidation stirring tank 2, the acid-base adjustment tank 3, the reduction precipitation tank 4, the first-stage mixed liquid buffer tank 5, the first-stage filtrate buffer tank 8, the neutralization tank 9, the neutralization mixed liquid buffer tank 10 and the second-stage filtrate buffer tank 13 are all cylindrical closed tanks with mechanical stirring devices, and reaction gas collection pipes 14 are provided at the tops of the first-stage oxidation stirring tank 1, the second-stage oxidation stirring tank 2, the acid-base adjustment tank 3, the reduction precipitation tank 4, the first-stage mixed liquid buffer tank 5 and the first-stage filtrate buffer tank 8, oxidation chemical dosing pipes 15 are provided at the tops of the first-stage oxidation stirring tank 1 and the second-stage oxidation stirring tank 2, an acid-base chemical dosing pipe 16 is provided at the top of the acid-base adjustment tank 3, a reduction precipitant dosing pipe 17 is provided at the top of the reduction precipitation tank 4, and a neutralization chemical dosing pipe 18 is provided at the top of the neutralization tank 9;

[0007] Among the first-stage oxidation stirring tank 1, the second-stage oxidation stirring tank 2, the acid-base adjustment tank 3, the reduction precipitation tank 4 and the first-stage mixed liquid buffer tank 5, every two adjacent tanks are interconnected. The outlet of the first-stage mixed liquid buffer tank 5 is connected to the inlet of the first-stage filtration device 7 through a first centrifugal pump 6, the outlet of the first-stage filtration device 7 is connected to the inlet of the first-stage filtrate buffer tank 8, among the first-stage filtrate buffer tank 8, the neutralization tank 9 and the neutralization mixed liquid buffer tank 10, every two adjacent tanks are interconnected. The outlet of the neutralization mixed liquid buffer tank 10 is connected to the inlet of the mixed liquid filtration device 12 through a second centrifugal pump 11, and the outlet of the mixed liquid filtration device 12 is connected to the inlet of the second-stage filtrate buffer tank 13.

[0008] The overflow port of the first-stage oxidation stirring tank 1 is connected to the liquid inlet of the second-stage oxidation stirring tank 2, the overflow port of the second-stage oxidation stirring tank 2 is connected to the liquid inlet of the acid-base adjustment tank 3, the overflow port of the acid-base adjustment tank 3 is connected to the liquid inlet of the reduction precipitation tank 4, and the overflow port of the reduction precipitation tank 4 is connected to the liquid inlet of the first-stage mixed liquid buffer tank 5.

[0009] The overflow port of the first-stage filtrate buffer tank 8 is connected to the liquid inlet of the neutralization tank 9, and the overflow port of the neutralization tank 9 is connected to the liquid inlet of the neutralization mixed liquid buffer tank 10.

[0010] The first-stage filtration device 7 and the neutralization mixed liquid filtration device 12 are plate and frame filter presses, ceramic filter presses, centrifugal filters or pipeline filters.

[0011] The reaction gases generated in the primary oxidation stirring tank 1, secondary oxidation stirring tank 2, acid-base adjustment tank 3, reduction precipitation tank 4, primary mixed liquid buffer tank 5, and primary filtrate buffer tank 8 are uniformly collected through the gas collection pipes 14 at the tops of their respective tank bodies and then introduced into an alkali solution for absorption treatment.

[0012] Advantages of the present utility model:

[0013] The present utility model realizes comprehensive treatment of first chemically oxidizing to break cyanide, then acidifying for reduction precipitation, and further neutralizing and purifying through multiple-stage tank bodies. Through the setting of tank bodies with various different functions, medium and low-concentration cyanide-containing wastewater containing cyanide, heavy metals and their complexes, especially copper cyanide complexes that are difficult to remove, can be effectively purified; it solves the problems of continuous accumulation of refractory pollutants, affecting production process indicators, and affecting the treatment effect of tailings slurry during the enterprise's circulating water reuse process.

[0014] The present utility model has a simple process flow, stable system operation, good treatment effect, is easy to realize industrial application, and has broad application prospects. Description of the drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings to be used in the description of the embodiments of the present utility model. Obviously, the following-described drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the content of the embodiments of the present utility model and these drawings.

[0016] Figure 1 It is a structural schematic diagram of the present utility model.

[0017] Among them: primary oxidation stirring tank 1, secondary oxidation stirring tank 2, acid-base adjustment tank 3, reduction precipitation tank 4, primary mixed liquid buffer tank 5, first centrifugal pump 6, primary filtration device 7, primary filtrate buffer tank 8, neutralization tank 9, neutralization mixed liquid buffer tank 10, second centrifugal pump 11, neutralization mixed liquid filtration device 12, secondary filtrate buffer tank 13, reaction gas collection pipe 14, oxidation reagent dosing pipe 15, acid-base reagent dosing pipe 16, reduction precipitant dosing pipe 17, neutralization reagent dosing pipe 18, liquid inlet pump 19. Specific implementation manners

[0018] The following will further elaborate on the present utility model in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present utility model, rather than limiting the present utility model. Additionally, it should be noted that for the sake of description, only parts related to the present utility model rather than all structures are shown in the drawings.

[0019] Embodiment 1

[0020] A treatment system for difficult-to-treat cyanide-containing wastewater with medium and low concentrations, comprising a first-stage oxidation stirring tank 1, a second-stage oxidation stirring tank 2, an acid-base adjustment tank 3, a reduction precipitation tank 4, a first-stage mixed liquid buffer tank 5, a first-stage filtration device 7, a first-stage filtrate buffer tank 8, a neutralization tank 9, a neutralization mixed liquid buffer tank 10, a neutralization mixed liquid filtration device 12 and a second-stage filtrate buffer tank 13; wherein the first-stage oxidation stirring tank 1, the second-stage oxidation stirring tank 2, the acid-base adjustment tank 3, the reduction precipitation tank 4, the first-stage mixed liquid buffer tank 5, the first-stage filtrate buffer tank 8, the neutralization tank 9, the neutralization mixed liquid buffer tank 10 and the second-stage filtrate buffer tank 13 are all cylindrical closed tanks with mechanical stirring devices, and reaction gas collection pipes 14 are provided at the tops of the first-stage oxidation stirring tank 1, the second-stage oxidation stirring tank 2, the acid-base adjustment tank 3, the reduction precipitation tank 4, the first-stage mixed liquid buffer tank 5 and the first-stage filtrate buffer tank 8. Oxidation agent dosing pipes 15 are provided at the tops of the first-stage oxidation stirring tank 1 and the second-stage oxidation stirring tank 2, an acid-base agent dosing pipe 16 is provided at the top of the acid-base adjustment tank 3, a reduction precipitant dosing pipe 17 is provided at the top of the reduction precipitation tank 4, and a neutralization agent dosing pipe 18 is provided at the top of the neutralization tank 9;

[0021] Among the first-stage oxidation stirring tank 1, the second-stage oxidation stirring tank 2, the acid-base adjustment tank 3, the reduction precipitation tank 4 and the first-stage mixed liquid buffer tank 5, every two adjacent tanks are interconnected. The outlet of the first-stage mixed liquid buffer tank 5 is connected to the inlet of the first-stage filtration device 7 through a first centrifugal pump 6, the outlet of the first-stage filtration device 7 is connected to the inlet of the first-stage filtrate buffer tank 8, and every two adjacent tanks among the first-stage filtrate buffer tank 8, the neutralization tank 9 and the neutralization mixed liquid buffer tank 10 are interconnected. The outlet of the neutralization mixed liquid buffer tank 10 is connected to the inlet of the mixed liquid filtration device 12 through a second centrifugal pump 11, and the outlet of the mixed liquid filtration device 12 is connected to the inlet of the second-stage filtrate buffer tank 13.

[0022] The overflow port of the first-stage oxidation stirring tank 1 is connected to the liquid inlet of the second-stage oxidation stirring tank 2, the overflow port of the second-stage oxidation stirring tank 2 is connected to the liquid inlet of the acid-base adjustment tank 3, the overflow port of the acid-base adjustment tank 3 is connected to the liquid inlet of the reduction precipitation tank 4, and the overflow port of the reduction precipitation tank 4 is connected to the liquid inlet of the first-stage mixed liquid buffer tank 5.

[0023] The overflow port of the first-stage filtrate buffer tank 8 is connected to the liquid inlet of the neutralization tank 9, and the overflow port of the neutralization tank 9 is connected to the liquid inlet of the neutralization mixed liquid buffer tank 10.

[0024] The first-stage filtration device 7 and the neutralization mixed liquid filtration device 12 are plate-and-frame filter presses, ceramic filter presses, centrifugal filters or pipeline filters.

[0025] The reaction gases generated in the first-stage oxidation stirring tank 1, the second-stage oxidation stirring tank 2, the acid-base adjustment tank 3, the reduction precipitation tank 4, the first-stage mixed liquid buffer tank 5, and the first-stage filtrate buffer tank 8 are uniformly collected through the gas collection pipes 14 at the tops of their respective tank bodies and then introduced into an alkali solution for absorption treatment.

[0026] The mechanical stirring devices on each tank body include a motor, a stirring shaft, and blades. The motor is fixed on the top of the corresponding tank body through a bracket, and its transmission shaft is connected to the stirring shaft and can drive the stirring shaft to rotate. The stirring shaft extends into the corresponding tank body, and multiple blades are provided at the bottom.

[0027] The usage process is as follows:

[0028] The cyanide tailings slurry, the leachate of the difficult-to-treat tailings pond, or other medium- and low-concentration cyanide-containing wastewater to be treated is added to the first-stage oxidation stirring tank 1 through the feed pump 19, and an oxidation agent is added to the first-stage oxidation stirring tank 1 through the oxidation agent dosing pipe 15. The mechanical stirring device is started for stirring. After the first-stage oxidation stirring tank 1 is filled, the liquid therein overflows into the second-stage oxidation stirring tank 2 through its overflow port. An oxidation agent is added to the second-stage oxidation stirring tank 2 through the oxidation agent dosing pipe 15. The mechanical stirring device is started for stirring. After the second-stage oxidation stirring tank 2 is filled, the liquid therein overflows into the acid-base adjustment tank 3 through its overflow port. Sulfuric acid is added to the acid-base adjustment tank 3 through the acid-base agent dosing pipe 16. The mechanical stirring device is started to stir and mix the liquid in the acid-base adjustment tank 3, and then the pH of the liquid in the acid-base adjustment tank 3 is adjusted to the required level. After the acid-base adjustment tank 3 is filled, it overflows into the reduction precipitation tank 4 through its overflow port. A reduction precipitant is added to the reduction precipitation tank 4 through the reduction precipitant dosing pipe 17. The mechanical stirring device is started for stirring. After the reduction precipitation tank 4 is filled, the liquid therein overflows into the first-stage mixed liquid buffer tank 5 through its overflow port. After buffering for the required time in the first-stage mixed liquid buffer tank 5, the first centrifugal pump 6 is started to pump the mixed liquid generated in the oxidation process and the acidification reduction precipitation process to the first-stage filtration device 7. The filtrate after being filtered by the first-stage filtration device 7 overflows into the first-stage filtrate buffer tank 8 and buffers in the first-stage filtrate buffer tank 8. When the liquid in the first-stage filtrate buffer tank 8 is full, it overflows into the neutralization tank 9. The required agent is added to the neutralization tank 9 through the neutralization agent dosing pipe 18. The mechanical stirring device is started for stirring. When the liquid in the neutralization tank 9 is full, the liquid overflows into the neutralization mixed liquid buffer tank 10 through the overflow port of the neutralization tank 9. After buffering for the required time in the neutralization mixed liquid buffer tank 10, the second centrifugal pump 11 is started to pump the mixed liquid generated in the neutralization process to the neutralization mixed liquid filtration device 12 for filtration. The filtrate overflows into the second-stage filtrate buffer tank 13 for buffering, and the treated and purified wastewater is obtained.

[0029] Among them, the reaction gases generated in the first-stage oxidation stirring tank 1, the second-stage oxidation stirring tank 2, the acid-base adjustment tank 3, the reduction precipitation tank 4, the first-stage mixed liquid buffer tank 5, and the first-stage filtrate buffer tank 8 are uniformly collected by the gas collection pipes 14 at the tops of the corresponding tank bodies and then treated by alkali solution absorption.

[0030] In summary, for refractory complex cyanides and heavy metals, the acidification reduction coprecipitation method is further used to remove cyanides that are difficult to oxidize and decompose. The mixed liquid after precipitation is pressure-filtered, and the tail liquid can reach the purpose of wastewater purification after neutralization, promoting the virtuous cycle of the system.

[0031] Example 2

[0032] Please refer to Figure 1 As shown, it is composed of a first-stage oxidation stirring tank 1, a second-stage oxidation stirring tank 2, an acid-base adjustment tank 3, a reduction precipitation tank 4, a first-stage mixed liquid buffer tank 5, a first-stage filtration device 7, a first-stage filtrate buffer tank 8, a neutralization tank 9, a neutralization mixed liquid buffer tank 10, a neutralization mixed liquid filtration device 12, a second-stage filtrate buffer tank 13, pumps and pipelines.

[0033] Among them, the first-stage oxidation stirring tank 1, the second-stage oxidation stirring tank 2, the acid-base adjustment tank 3, the reduction precipitation tank 4, and the first-stage mixed liquid buffer tank 5 are all cylindrical closed tank bodies with mechanical stirring devices. Reaction gas collection pipes 14 are provided at the tops of each tank body. Oxidation agent dosing pipes 15 are provided at the tops of the first-stage oxidation stirring tank 1 and the second-stage oxidation stirring tank 2. An acid-base agent dosing pipe 16 is provided at the top of the acid-base adjustment tank 3. A reduction precipitation agent dosing pipe 17 is provided at the top of the reduction precipitation tank 4; the wastewater between each tank body overflows from the upper stage to the lower stage through the height difference, and the pipelines are connected from the overflow port of the upper stage to the liquid inlet of the lower stage; a first centrifugal pump 6 is provided between the first-stage mixed liquid buffer tank 5 and the first-stage filtration device 7 to pump the mixed liquid generated in the oxidation process and the acidification reduction precipitation process to the first-stage filtration device 7, and the filtrate overflows into the first-stage filtrate buffer tank 8. The first-stage filtrate buffer tank 8 is a cylindrical closed tank body with a mechanical stirring device, and a reaction gas collection pipe 14 is provided at the top; the mixed liquid between the first-stage filtrate buffer tank 8, the neutralization tank 9, and the neutralization mixed liquid buffer tank 10 all overflows from the upper stage to the lower stage through the height difference, and the pipelines are connected from the overflow port of the upper stage to the liquid inlet of the lower stage; a second centrifugal pump 11 is provided between the neutralization mixed liquid buffer tank 10 and the neutralization mixed liquid filtration device 12 to pump the mixed liquid generated in the neutralization process to the neutralization mixed liquid filtration device 12, and the filtrate overflows into the second-stage filtrate buffer tank 13; the neutralization tank 9, the neutralization mixed liquid buffer tank 10, and the second-stage filtrate buffer tank 13 are all cylindrical tank bodies with mechanical stirring devices, and a neutralization agent dosing pipe 18 is provided at the top of the neutralization tank 9.

[0034] The oxidation agents added into the oxidation agent dosing pipes 15 at the tops of the first-stage oxidation stirring tank 1 and the second-stage oxidation stirring tank 2 are hydrogen peroxide, sodium metabisulfite, and sodium sulfite agents;

[0035] The chemical agent added into the chemical agent dosing pipe 16 at the top of the acid-base regulation tank 3 is sulfuric acid;

[0036] The chemical agents added into the reduction precipitation agent dosing pipe 17 at the top of the reduction precipitation tank 4 are sodium sulfite, sodium metabisulfite, ascorbic acid, and heavy metal capturer reduction precipitation agents;

[0037] The chemical agents added into the neutralization agent dosing pipe 18 at the top of the neutralization tank 9 are lime, sodium hydroxide, PAM, PAC, and calcium hydroxide neutralization and flocculation agents;

[0038] The primary filtration device 7 and the neutralization mixed liquid filtration device 12 are plate and frame filter presses, ceramic filter presses, centrifugal filters, pipeline filters, or other forms of filtration devices;

[0039] The reaction gases of the primary oxidation stirring tank 1, the secondary oxidation stirring tank 2, the acid-base regulation tank 3, the reduction precipitation tank 4, the primary mixed liquid buffer tank 5, and the primary filtrate buffer tank 8 are uniformly collected by the gas collection pipe 14 at the top of the tank body and then treated by alkali solution absorption;

[0040] The chemical agent dosing pipes at the top of the tank body, the tank body, the stirring device, the connecting pipes, pipe fittings, and pumps between the devices are all made of acid and alkali corrosion-resistant materials.

[0041] The preferred embodiments of the present utility model have been described in detail above in conjunction with the accompanying drawings. However, the protection scope of the present utility model is not limited to the specific details in the above embodiments. Within the technical concept of the present utility model, any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution and the technical concept of the present utility model, makes equivalent substitutions or changes, and these simple modifications all belong to the protection scope of the present utility model.

[0042] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without conflict. To avoid unnecessary repetition, the present utility model will not separately describe various possible combination methods.

[0043] In addition, any combination can be made between various different embodiments of the present utility model, as long as it does not violate the idea of the present utility model, and it should also be regarded as the content disclosed by the present utility model.

Claims

1. A system for treating medium and low concentration difficult-to-treat cyanide-containing wastewater, characterized in that: The invention comprises a primary oxidation stirring tank (1), a secondary oxidation stirring tank (2), an acid-base regulating tank (3), a reduction precipitation tank (4), a primary mixed liquid buffer tank (5), a primary filtering device (7), a primary filtrate buffer tank (8), a neutralization tank (9), a neutralization mixed liquid buffer tank (10), a neutralization mixed liquid filtering device (12) and a secondary filtrate buffer tank (13); wherein the primary oxidation stirring tank (1), the secondary oxidation stirring tank (2), the acid-base regulating tank (3), the reduction precipitation tank (4), the primary mixed liquid buffer tank (5), the primary filtrate buffer tank (8), the neutralization tank (9), the neutralization mixed liquid buffer tank (10) and the secondary filtrate buffer tank (13) are cylindrical tank bodies with mechanical stirring devices, and the tops of the primary oxidation stirring tank (1), the secondary oxidation stirring tank (2), the acid-base regulating tank (3), the reduction precipitation tank (4), the primary mixed liquid buffer tank (5) and the primary filtrate buffer tank (8) are all provided with reaction gas collection pipes (14), the tops of the primary oxidation stirring tank (1) and the secondary oxidation stirring tank (2) are all provided with oxidizing agent dosing pipes (15), the tops of the acid-base regulating tank (3) are provided with acid-base agent dosing pipes (16), the tops of the reduction precipitation tank (4) are provided with reducing precipitant dosing pipes (17), and the tops of the neutralization tank (9) are provided with neutralizing agent dosing pipes (18); In the primary oxidation stirring tank (1), the secondary oxidation stirring tank (2), the acid-base adjustment tank (3), the reduction precipitation tank (4), and the primary mixed liquid buffer tank (5), each two adjacent tank bodies are connected to each other, the outlet of the primary mixed liquid buffer tank (5) is connected to the inlet of the primary filtering device (7) through a first centrifugal pump (6), the outlet of the primary filtering device (7) is connected to the inlet of the primary filtrate buffer tank (8), the primary filtrate buffer tank (8), the neutralization tank (9), and the neutralization mixed liquid buffer tank (10), each two adjacent tank bodies are connected to each other, the outlet of the neutralization mixed liquid buffer tank (10) is connected to the inlet of the mixed liquid filtering device (12) through a second centrifugal pump (11), and the outlet of the mixed liquid filtering device (12) is connected to the inlet of the secondary filtrate buffer tank (13).

2. A medium- and low-concentration difficult-to-treat cyanide-containing wastewater treatment system according to claim 1, characterized in that: The overflow port of the primary oxidation stirring tank (1) is connected to the liquid inlet of the secondary oxidation stirring tank (2), the overflow port of the secondary oxidation stirring tank (2) is connected to the liquid inlet of the acid-base adjustment tank (3), the overflow port of the acid-base adjustment tank (3) is connected to the liquid inlet of the reduction precipitation tank (4), and the overflow port of the reduction precipitation tank (4) is connected to the liquid inlet of the primary mixed liquid buffer tank (5).

3. A medium-low concentration difficult-to-treat cyanide-containing wastewater treatment system according to claim 1, characterized in that: The overflow port of the primary filtrate buffer tank (8) is communicated with the liquid inlet of the neutralization tank (9), and the overflow port of the neutralization tank (9) is communicated with the liquid inlet of the neutralization mixed liquid buffer tank (10).

4. A medium-low concentration difficult-to-treat cyanide-containing wastewater treatment system according to claim 1, characterized in that: The primary filtering device (7) and the neutralized mixed liquid filtering device (12) are plate-and-frame filter presses, ceramic filter presses, centrifugal filters, and pipeline filters.

5. A medium-low concentration difficult-to-treat cyanide-containing wastewater treatment system according to claim 1, characterized in that: The reaction gases generated in the primary oxidation stirring tank (1), the secondary oxidation stirring tank (2), the acid-base adjustment tank (3), the reduction precipitation tank (4), the primary mixed liquid buffer tank (5), and the primary filtrate buffer tank (8) are all collected through the gas collection pipes (14) at the top of the respective tank bodies and then passed into the alkaline solution for absorption treatment.

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