Cyanide-containing wastewater treatment method

Abstract

The invention relates to a cyanide-containing wastewater treatment method. The method comprises the following specific steps: physical filtration; filtering with a permeable membrane; adjusting the pH value; carrying out air stripping treatment; adjusting the pH value for the second time; coagulating and precipitating; biological activated carbon treatment; wherein a waste liquid spray head and a plurality of filler layers are arranged in the air stripping tower adopted in the step S4, and an air blower is outwards connected below the filler layer on the bottommost side; a plurality of liquid outlet branch pipes are arranged in a liquid collecting area at the bottom of the air stripping tower in a parallel communication manner, ultramicro bubble air outlet pipes are coaxially sleeved in the liquid outlet branch pipes, and the end parts, positioned in the air stripping tower, of the liquid outlet branch pipes are arranged in an open shape and are coaxially and fixedly provided with flow dividers; the flow divider is located at the open end of the liquid outlet branch pipe and is in a spherical surface shape, and the end, located on one side of the ultramicro bubble air outlet pipe, of the flow divider is in a conical shape. According to the invention, the absorption amount and efficiency of air stripping can be ensured by only performing air stripping treatment through the first-stage air stripping tower, so that the treatment quality of the cyanide-containing wastewater is improved, the environmental protection is ensured, and secondary pollution is effectively avoided.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, in particular to a method for treating cyanide-containing wastewater. Background Art

[0002] Gold cyaniding enterprises produce a large amount of cyanide-containing wastewater in the gold beneficiation process due to the use of cyanide gold extraction technology. This part of cyanide-containing wastewater not only contains a certain amount of highly toxic cyanide, but also contains thiocyanate and heavy metal ions such as copper, zinc, and lead. If it is not effectively treated, it will cause major environmental hazards. At present, the commonly used methods for treating cyanide-containing wastewater at home and abroad include acid recovery method, alkaline chlorine method, Inco method, sulfur dioxide method, etc. Among them, the treatment of cyanide-containing wastewater needs to be treated by multi-stage series acidification stripping equipment. By spraying the waste liquid onto the packing layer of the multi-layer distributed acid solution and then passing air, it needs to go through multi-stage series stripping equipment and rely on a long time of treatment to make the waste liquid fully contact with the acid, so the overall equipment structure is relatively large. However, as the amount of cyanide in the waste liquid decreases, the contact rate becomes lower and lower, and the absorption amount becomes less and less, resulting in large space occupied by the equipment and relatively wasteful equipment. In addition, when the amount of waste liquid is large, simply relying on extending the treatment time is not only inefficient, but more importantly, it is difficult to cope with production pressure and demand. However, simply reducing the number of stripping equipment will reduce the quality of the stripping treatment, and the treatment is not thorough, and there is still a lot of pollution.

[0003] Therefore, the research purpose of the present invention is to design a method for treating cyanide-containing wastewater which only needs to pass through a first-stage stripping tower to ensure the absorption amount and efficiency of the stripping, so as to improve the treatment quality of cyanide-containing wastewater, ensure environmental protection, and effectively avoid secondary pollution. Summary of the invention

[0004] In view of the technical problems existing in the above-mentioned prior art, the present invention provides a method for treating cyanide-containing wastewater, which can effectively solve the technical problems existing in the above-mentioned prior art.

[0005] The technical solution of the present invention is:

[0006] A method for treating cyanide-containing wastewater comprises the following steps:

[0007] S1, physical filtration: After the cyanide-containing wastewater is filtered through the screen, it is sent to the sand filtration treatment system to remove large solid pollutants in the wastewater;

[0008] S2, osmotic membrane filtration: the wastewater is introduced into the reverse osmosis treatment system for reverse osmosis membrane treatment to obtain reverse osmosis concentrate;

[0009] S3, pH value adjustment: add sulfuric acid to the reverse osmosis concentrate to adjust the pH to between 2-3, and control the temperature of the reverse osmosis concentrate at 30-40°C;

[0010] S4, stripping treatment, pumping the waste liquid with a temperature of 30-40° C. obtained in the above step S3 into a stripping tower, and introducing air for acidification stripping treatment, and absorbing the stripped gas with a sodium hydroxide solution;

[0011] S5, secondary pH value adjustment: the waste liquid after acid stripping is passed into the adjustment tank and the pH is adjusted to between 8-10 with alkali solution, and ozone is introduced;

[0012] S6, coagulation and sedimentation: the oxidized wastewater is passed into a sedimentation tank, and a coagulant is added during the stirring process for coagulation and sedimentation. After coagulation, the wastewater enters a sedimentation tank and is allowed to stand for 15-120 minutes;

[0013] S7, biological activated carbon treatment: the supernatant after precipitation enters the biological activated carbon treatment system, and is subjected to biological activated carbon treatment under the conditions of activated carbon filler, biofilm bacteria and air;

[0014] S8, the treated waste liquid enters the return pool for returning to the production process or being discharged in compliance with the standards;

[0015] Among them, a plurality of waste liquid nozzles are distributed on the top of the stripping tower used in the step S4, and a plurality of packing layers are arranged at intervals above and below the waste liquid nozzles in the stripping tower, and a corresponding blower is connected to the outside under the bottommost packing layer; a corresponding liquid collecting area is arranged at the bottom of the stripping tower, and a corresponding liquid outlet main pipe is arranged on one side of the liquid collecting area to the outside, and a plurality of liquid outlet branch pipes are arranged in parallel at the liquid inlet end of the liquid outlet main pipe, and the liquid outlet branch pipes are installed side by side at intervals on the left and right in the liquid collecting area of ​​the stripping tower, and a corresponding ultrafine bubble outlet pipe is coaxially sleeved at one end of the liquid outlet branch pipe not connected to the stripping tower, and the ultrafine bubble outlet pipe extends outward and is connected to the ultrafine bubble generator on the outside; the end of the liquid outlet branch pipe located in the stripping tower is open, and a corresponding flow divider is coaxially fixedly installed, and the open end of the flow divider located at the liquid outlet branch pipe is spherical, and the end located on one side of the ultrafine bubble outlet pipe is conical.

[0016] The alkali solution in step S5 is sodium hydroxide or lime milk, and the coagulant in step S6 is a polymeric inorganic salt coagulant or a high molecular inorganic salt solution with a mass fraction of 10%-30%.

[0017] The biological activated carbon treatment system of step S6 is an upflow or downflow reaction tank, with a water distribution device and an aeration device at the bottom of the tank, an activated carbon filler layer above the aeration device, and the carbon loading volume accounts for 1 / 5-4 / 5 of the reactor volume; the biofilm bacteria are nitrite bacteria and nitrifying bacteria or cyanide-reducing bacteria, the biofilm formation method is artificial addition of bacteria or dynamic cultivation of natural biofilm, the gas-liquid ratio is 1-15:1, and the biological activated carbon treatment time is 30min-120min.

[0018] The spherical end of the diverter in the stripping tower in step S4 is circumferentially provided with a plurality of radially arranged positioning rods, and both ends of the positioning rods are fixedly mounted on the inner side wall of the liquid outlet pipe and the spherical end of the diverter.

[0019] The waste liquid nozzle is connected to the waste liquid outlet of step S3 through a corresponding liquid extraction pump and a liquid guide valve. The corresponding liquid outlet valve and liquid outlet pump are installed on the liquid outlet main pipe. The liquid guide valve and liquid outlet valve are automatic valves and are electrically connected to the control system together with the liquid extraction pump, liquid outlet pump, blower and ultrafine bubble generator.

[0020] The upper part of the precipitation tank in step S6 is fixedly installed with a corresponding cover, on which a feed pipe and a liquid inlet pipe are arranged, and the middle side and bottom of the precipitation tank are respectively provided with corresponding supernatant liquid outlet pipe and discharge pipe; the lower side of the cover is rotatably installed with a corresponding stirring shaft, on which a plurality of staggered stirring rods are fixedly installed from top to bottom, and a V-shaped stirring piece is installed at the end of the stirring rod through a sleeved tubular flexible piece, and the V-shaped opening of the stirring piece can be adjusted; the stirring piece and the stirring rod are relatively inner Matching trigger members and micro switches are respectively arranged on the side surfaces. When the V-shaped opening of the stirring member is opened, the trigger member fixedly mounted on the stirring member moves toward the side of the stirring rod along with the end of the stirring member and touches the micro switch, thereby controlling the stirring shaft to rotate in the opposite direction through electrical connection. A corresponding pressure sensor is installed on the stirring rod and embedded in the tubular flexible member. The detection end of the pressure sensor abuts against the connection between the stirring member and the tubular flexible member. When the pressure value detected by the pressure sensor is greater than F1, the forward and reverse motors stop.

[0021] The liquid inlet pipe is connected to the waste liquid outlet in step S5 through a corresponding intermediate pump and an intermediate valve.

[0022] The stirring member comprises two plate blades whose ends are hinged to each other. The plate blades are respectively tangentially fixed to the tubular flexible member, and the tubular flexible member is made of deformable rubber material. When the two plate blades on the stirring member are opened, the tubular flexible member is stretched.

[0023] The stirring shaft is driven to rotate forward and reversely by a forward and reverse motor installed above the cover. When the micro switch is triggered, the forward and reverse motor rotates in the reverse direction.

[0024] The bottom side of the sealing cover is fixedly connected downwardly with a corresponding mounting tube at a position corresponding to the stirring shaft, and the stirring shaft is rotatably sleeved on the mounting tube through a corresponding bearing; the sedimentation tank is supported and installed by corresponding supporting legs, and a corresponding closing cover is installed on the feed pipe in an openable and closable manner, and corresponding liquid inlet valves, discharge valves and discharge valves are fixedly installed on the liquid inlet pipe, supernatant liquid outlet pipe and discharge pipe respectively.

[0025] Advantages of the present invention:

[0026] 1) The present invention treats the waste liquid of cyanide gold extraction through physical filtration, osmotic membrane filtration, pH value adjustment, air stripping treatment, secondary pH value adjustment, coagulation precipitation and biological activated carbon treatment to effectively reduce environmental pollution, and only one-stage air stripping tower is used during the air stripping treatment, and a blower is provided in the air stripping tower, and a plurality of ultrafine bubble generators arranged side by side are additionally provided, and the outlet pipe of the ultrafine bubble generator is coaxially sleeved in the corresponding liquid outlet branch pipe, and the pipe mouth of the liquid outlet branch pipe is open and coaxially fixed with a diverter with a spherical end and a conical other end. With the waste liquid flowing outward through the discharge pump, ultrafine bubbles are sprayed inward in the opposite direction, so that the air and the air-soluble impurities in the flowing waste liquid can be further fully contacted and dissolved, thereby effectively improving the effect and quality of the stripping and shortening the duration of the stripping. The waste liquid is treated by the relative setting of the water flow and the bubble spray direction, the charged adsorption on the bubble surface, and the high density of ultrafine bubbles. Not only can the pollutants that are soluble in air be blown out, but also some pollutants can be strongly oxidized and decomposed, thereby further improving the treatment effect of cyanide-containing wastewater.

[0027] 2) The open end of the diverter of the present invention is spherically arranged at the liquid outlet branch pipe, and the end on the side of the ultrafine bubble outlet pipe is conically arranged, and a plurality of radially arranged positioning rods are distributed along the circumference at the spherical end of the diverter for fixing and installing the diverter. The diverter can be used to evenly disperse and guide the waste liquid outward, and evenly disperse and guide the ultrafine bubbles inward, thereby ensuring the uniformity and stability of waste liquid treatment.

[0028] 3) The present invention further improves the sedimentation tank by installing a number of staggered stirring rods from top to bottom on a stirring shaft that can rotate forward and reverse, and installing a stirring piece that is V-shaped and has an adjustable V-shaped opening angle on the outside of the stirring rod through a sleeved tubular flexible piece. When the waste liquid and coagulant are just put into the sedimentation tank, the resistance is small. The forward rotation of the stirring shaft drives one side of the V-shaped opening of the stirring piece to rotate in the stirring direction, thereby driving the plate blades of the stirring piece to fully mix the waste liquid and coagulant, greatly improving the mixing efficiency and the coagulation and sedimentation effect; when the waste liquid slowly settles and the stirring resistance gradually increases, the angle of the V-shaped opening of the stirring piece will gradually increase, and the trigger piece fixed to the hinged end of the stirring piece will move toward the side of the tubular flexible piece as the hinged end moves to the side of the tubular flexible piece and touch the micro switch installed on the stirring rod, thereby electrically connecting the forward and reverse motor to drive the stirring shaft to rotate in the opposite direction, and driving the end of the V-shaped pointed cone of the stirring piece to face the rotation direction to reduce contact. The stirring is carried out in a manner of area to promote smooth stirring, and the inclined side of the stirring piece can guide the material and promote the mixing, thereby improving the mixing effect and efficiency in the precipitation stage on the basis of improving the practical effect; furthermore, when the stirring piece rotates in the opposite direction, its V-shaped opening will gradually shrink and press the tubular flexible piece under the action of resistance, and when the extruded pressure of the tubular flexible piece reaches the pressure value specified by the pressure sensor, the electric drive motor stops stirring and the waste liquid is precipitated, so that the stirring can be controlled according to the coagulation situation in the waste liquid, the treatment is more precise, the effect is better, energy saving and automation can be achieved, and it is more suitable for gold cyanide enterprises with large waste liquid treatment volume and short treatment time.

[0029] 4) The present invention comprises a stirring element through two plate blades which are hingedly arranged and connected in a V shape. When rotating in the forward direction, the stirring contact surface is ensured to be large enough to improve the stirring efficiency and the coagulation effect. When rotating in the reverse direction, the V-shaped pointed cone ensures the reduction of the contact surface and the diversion. A tubular flexible member made of rubber material is used to install the plate blades. The tubular flexible member made of rubber material has a stretchable and resettable deformation amount, which is sufficient to adapt to the increase in the angle of the V-shaped opening of the stirring element when the resistance increases and the decrease in the angle of the V-shaped opening when rotating in the reverse direction. Through the intervention of the elastic member of the tubular flexible member, the opening and compression of the stirring element are controlled to ensure the practical effect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the stripping tower, the regulating tank and the sedimentation tank in the present invention.

[0031] Figure 2 for Figure 1 Schematic cross-section diagram.

[0032] Figure 3 This is a cross-sectional view of the installation of the diverter and the liquid outlet pipe in the present invention.

[0033] Figure 4It is a cross-sectional schematic diagram of the sedimentation tank in the present invention (the driving motor rotates forward).

[0034] Figure 5 for Figure 4 Schematic diagram of the state of the drive motor when it is reversed.

[0035] Figure 6 It is a schematic diagram of the structure of the stirring element (the driving motor rotates forward).

[0036] Figure 7 for Figure 6 Schematic diagram of the state of the drive motor when it is reversed.

[0037] In the accompanying drawings: a stripping tower 1, a waste liquid nozzle 2, a packing layer 3, a blower 4, a liquid collecting area 5, a liquid outlet main pipe 6, a liquid outlet branch pipe 7, an ultrafine bubble outlet pipe 8, a diverter 9, a positioning rod 10, a liquid suction pump 11, a liquid guide valve 12, a liquid outlet valve 13, a liquid outlet pump 14, a sedimentation tank 15, a sealing cover 16, a feed pipe 17, a liquid inlet pipe 18, a discharge pipe 19, a stirring shaft 20, a stirring rod 21, a tubular flexible part 22, a stirring part 23, a plate blade 2301, a trigger part 24, a micro switch 25, a forward and reverse motor 26, a support leg 28, an ultrafine bubble generator 29, a supernatant outlet pipe 30, a pressure sensor 31, and a regulating tank 32. DETAILED DESCRIPTION

[0038] In order to facilitate understanding by those skilled in the art, the structure of the present invention is further described in detail with reference to the embodiments in conjunction with the accompanying drawings:

[0039] refer to Figure 1-7 , a method for treating cyanide-containing wastewater, comprising the following steps:

[0040] S1, physical filtration: After the cyanide-containing wastewater is filtered through the screen, it is sent to the sand filtration treatment system to remove large solid pollutants in the wastewater;

[0041] S2, osmotic membrane filtration: the wastewater is introduced into the reverse osmosis treatment system for reverse osmosis membrane treatment to obtain reverse osmosis concentrate;

[0042] S3, pH value adjustment: add sulfuric acid to the reverse osmosis concentrate to adjust the pH to between 2-3, and control the temperature of the reverse osmosis concentrate at 30-40°C;

[0043] S4, stripping treatment, pumping the waste liquid with a temperature of 30-40° C. obtained in the above step S3 into the stripping tower 1, and introducing air for acidification stripping treatment, and the stripped gas is absorbed by sodium hydroxide solution;

[0044] S5, secondary pH value adjustment: the waste liquid after acid stripping is passed into the adjustment tank 32 and the pH is adjusted to between 8 and 10 with alkali solution, and ozone is introduced;

[0045] S6, coagulation and sedimentation: the oxidized wastewater is passed into the sedimentation tank 15, and a coagulant is added during the stirring process for coagulation and sedimentation. After coagulation, the wastewater enters the sedimentation tank and is left to stand for 15-120 minutes;

[0046] S7, biological activated carbon treatment: the supernatant after precipitation enters the biological activated carbon treatment system, and is subjected to biological activated carbon treatment under the conditions of activated carbon filler, biofilm bacteria and air;

[0047] S8, the treated waste liquid enters the return pool for returning to the production process or being discharged in compliance with the standards;

[0048] Among them, the top of the stripping tower 1 used in the step S4 is distributed with a plurality of waste liquid nozzles 2, and a plurality of packing layers 3 are arranged at intervals above and below the waste liquid nozzles 2 in the stripping tower 1, and a corresponding blower 4 is connected to the outside under the bottom packing layer 3; a corresponding liquid collecting area 5 is arranged at the bottom of the stripping tower 1, and one side of the liquid collecting area 5 is connected to the outside with a corresponding liquid outlet main pipe 6, and the liquid inlet end of the liquid outlet main pipe 6 is connected in parallel with a plurality of liquid outlet branch pipes 7, and the left and right sides of the liquid outlet branch pipes 7 are connected to the liquid outlet main pipe 6. The liquid collecting area 5 of the stripping tower 1 is installed side by side at intervals, and the end of the liquid outlet branch pipe 7 not connected to the stripping tower 1 is coaxially sleeved with a corresponding ultrafine bubble outlet pipe 8, and the ultrafine bubble outlet pipe 8 extends outward and is connected to the ultrafine bubble generator 29 on the outside; the end of the liquid outlet branch pipe 7 located in the stripping tower 1 is open, and a corresponding diverter 9 is coaxially fixedly installed, and the diverter 9 is spherically arranged at the open end of the liquid outlet branch pipe 7 and is conically arranged at the end on one side of the ultrafine bubble outlet pipe 8.

[0049] The present invention treats the waste liquid of cyanide gold extraction through physical filtration, osmotic membrane filtration, pH value adjustment, stripping treatment, secondary pH value adjustment, coagulation precipitation and biological activated carbon treatment to effectively reduce environmental pollution. In addition, only one-stage stripping tower 1 is used during the stripping treatment. In addition to a blower 4 for stripping, a plurality of ultrafine bubble generators 29 arranged side by side are additionally provided. The outlet pipe of the ultrafine bubble generator 29 is coaxially sleeved in the corresponding liquid outlet branch pipe 7. The pipe mouth of the liquid outlet branch pipe 7 is open and coaxially fixed with a diverter 9 with a spherical end and a conical end. The waste liquid is coordinated to flow outward through the liquid outlet pump 14, and ultrafine bubbles are sprayed inward in the opposite direction, so that the air and the air-soluble impurities in the flowing waste liquid are further fully contacted and dissolved, thereby effectively improving the effect and quality of the stripping and shortening the duration of the stripping. The waste liquid is treated by the relative arrangement of the water flow and the bubble spraying direction, the charged adsorption on the bubble surface, and the high density of the ultrafine bubbles. Not only the pollutants soluble in the air are blown out, but also some pollutants can be strongly oxidized and decomposed, thereby further improving the treatment effect of the cyanide-containing wastewater.

[0050] The alkali solution in step S5 is sodium hydroxide or lime milk, and the coagulant in step S6 is a polymeric inorganic salt coagulant or a high molecular inorganic salt solution with a mass fraction of 10%-30%.

[0051] The biological activated carbon treatment system of step S6 is an upflow or downflow reaction tank, a water distribution device and an aeration device are provided at the bottom of the tank, an activated carbon filler layer 3 is provided above the aeration device, and the carbon loading volume accounts for 1 / 5-4 / 5 of the reactor volume; the biofilm forming bacteria are nitrite bacteria and nitrifying bacteria or cyanide-reducing bacteria, the biofilm forming method is artificial addition of bacteria to form biofilm or dynamic cultivation of natural biofilm, the gas-liquid ratio is 1-15:1, and the biological activated carbon treatment time is 30min-120min.

[0052] The spherical end of the diverter 9 in the stripping tower 1 of step S4 is circumferentially distributed with a plurality of radially arranged positioning rods 10 , and both ends of the positioning rods 10 are fixedly mounted on the inner wall of the liquid outlet pipe 7 and the spherical end of the diverter 9 .

[0053] The diverter 9 of the present invention is disposed in a spherical shape at the open end of the liquid outlet branch pipe 7 and in a conical shape at the end on one side of the ultrafine bubble outlet pipe 8, and a plurality of radially disposed positioning rods 10 are distributed along the circumferential direction at the spherical end of the diverter 9 for fixing and installing the diverter 9. The diverter 9 can be used to evenly disperse and guide the waste liquid outward, and evenly disperse and guide the ultrafine bubbles inward, thereby ensuring the uniformity and stability of the waste liquid treatment.

[0054] The waste liquid nozzle 2 is connected to the waste liquid outlet of step S3 through the corresponding liquid extraction pump 11 and the liquid guide valve 12. The corresponding liquid outlet valve 13 and the liquid outlet pump 14 are installed on the liquid outlet main pipe 6. The liquid guide valve 12 and the liquid outlet valve 13 are automatic valves and are electrically connected to the control system together with the liquid extraction pump 11, the liquid outlet pump 14, the blower 4 and the ultrafine bubble generator 29.

[0055] The upper part of the precipitation tank 15 of step S6 is fixedly installed with a corresponding cover 16, and the cover 16 is provided with a feed pipe 17 and a liquid inlet pipe 18, and the middle side and bottom of the precipitation tank 15 are respectively provided with corresponding supernatant liquid outlet pipe 30 and discharge pipe 19; the lower side of the cover 16 is provided with a corresponding stirring shaft 20 that can rotate forward and reverse, and the stirring shaft 20 is fixedly installed with a plurality of staggered stirring rods 21 at intervals from top to bottom, and the end of the stirring rod 21 is provided with a V-shaped stirring member 23 through a sleeved tubular flexible member 22, and the V-shaped opening of the stirring member 23 can be adjusted; the stirring member 23 and the stirring rod 21 are relatively The inner side surfaces are respectively provided with matching trigger members 24 and micro switches 25. When the V-shaped opening of the stirring member 23 is opened, the trigger member 24 fixedly mounted on the stirring member 23 moves toward the stirring rod 21 along with the end of the stirring member 23 and triggers the micro switch 25, thereby controlling the stirring shaft 20 to rotate in the opposite direction through electrical connection. A corresponding pressure sensor 31 is mounted on the stirring rod 21 and embedded in the tubular flexible member 22. The detection end of the pressure sensor 31 abuts against the connection between the stirring member 23 and the tubular flexible member 22. When the pressure sensor 31 detects a pressure value greater than F1, the forward and reverse motor 26 stops.

[0056] The present invention further improves the sedimentation tank 15 by installing a plurality of staggered stirring rods 21 from top to bottom on a stirring shaft 20 that can rotate forwards and backwards, and installing a stirring member 23 with a V-shaped opening angle adjustable on the outer side of the stirring rod 21 through a tubular flexible member 22. When the waste liquid and coagulant are just put into the sedimentation tank 15, the resistance is relatively small. The stirring shaft 20 is used to rotate forward to drive one side of the V-shaped opening of the stirring member 23 to rotate in the stirring direction, thereby driving the plate blades 2301 of the stirring member 23 to fully mix the waste liquid and the coagulant, thereby greatly improving the mixing efficiency and the coagulation and sedimentation effect; when the waste liquid slowly settles and the stirring resistance gradually increases, the angle of the V-shaped opening of the stirring member 23 will gradually increase, and the trigger member 24 fixed to the hinged end of the stirring member 23 will move toward the side of the tubular flexible member 22 as the hinged end moves, thereby triggering the microswitch 25 installed on the stirring rod 21, thereby electrically connecting the forward and reverse motor 26 to drive the stirring shaft 20 to rotate in the opposite direction, and drive the end of the V-shaped pointed cone of the stirring member 23 to face the rotation direction. The stirring direction is adjusted to reduce the contact area for stirring, which promotes smooth stirring, and the inclined side of the stirring member 23 can guide the material and promote mixing, thereby improving the mixing effect and efficiency of the precipitation stage on the basis of improving the practical effect; furthermore, when the stirring member 23 rotates in the opposite direction, its V-shaped opening will gradually shrink and press the tubular flexible member 22 under the action of resistance, and when the pressure of the tubular flexible member 22 is squeezed to reach the pressure value specified by the pressure sensor 31, the electric drive motor stops stirring and the waste liquid is precipitated, so that the stirring can be controlled according to the coagulation situation in the waste liquid, the treatment is more precise, the effect is better, energy saving and automation can be achieved, and it is more suitable for gold cyanide enterprises with a large amount of waste liquid treatment and a short treatment time.

[0057] The liquid inlet pipe 18 is connected to the waste liquid outlet in step S5 through a corresponding intermediate pump and an intermediate valve.

[0058] The stirring member 23 comprises two plate blades 2301 whose ends are hinged to each other. The plate blades 2301 are respectively tangentially fixed to the tubular flexible member 22. The tubular flexible member 22 is made of deformable rubber material. When the two plate blades 2301 on the stirring member 23 are opened, the tubular flexible member 22 is stretched.

[0059] The present invention comprises two plate blades 2301 which are hingedly arranged and connected in a V shape to form a stirring element 23. When rotating in the forward direction, the stirring contact surface is ensured to be large enough to improve the stirring efficiency and the coagulation effect. When rotating in the reverse direction, the V-shaped pointed cone ensures the reduction of the contact surface and the diversion. The plate blades 2301 are installed by using a tubular flexible member 22 of rubber material. The tubular flexible member 22 of rubber material has a stretchable and resettable deformation amount, which is sufficient to adapt to the increase in the angle of the V-shaped opening of the stirring element 23 when the resistance increases and the decrease in the angle of the V-shaped opening when rotating in the reverse direction. Through the intervention of the elastic member of the tubular flexible member 22, the opening and compression of the stirring element 23 are controlled to ensure the practical effect of the present invention.

[0060] The stirring shaft 20 is driven to rotate forward and reverse by a forward and reverse motor 26 installed above the cover 16. When the micro switch 25 is triggered, the forward and reverse motor 26 rotates in the reverse direction.

[0061] The bottom side of the sealing cover 16 is fixedly connected downwardly with a corresponding mounting tube 27 at a position corresponding to the stirring shaft 20, and the stirring shaft 20 is rotatably sleeved on the mounting tube 27 through a corresponding bearing; the sedimentation tank 15 is supported and installed by corresponding supporting legs 28, and a corresponding closing cover is installed on the feed pipe 17 in an openable and closable manner, and corresponding liquid inlet valves, discharge valves and discharge valves are fixedly installed on the liquid inlet pipe 18, the supernatant liquid outlet pipe 30 and the discharge pipe 19 respectively.

[0062] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for treating cyanide-containing wastewater, characterized in that: The steps include: S1, physical filtration: After the cyanide-containing wastewater is filtered through the screen, it is sent to the sand filtration treatment system to remove large solid pollutants in the wastewater; S2, osmotic membrane filtration: the wastewater is introduced into the reverse osmosis treatment system for reverse osmosis membrane treatment to obtain reverse osmosis concentrate; S3, pH value adjustment: add sulfuric acid to the reverse osmosis concentrate to adjust the pH to between 2-3, and control the temperature of the reverse osmosis concentrate at 30-40°C; S4, stripping treatment, pumping the waste liquid with a temperature of 30-40° C. obtained in the above step S3 into the stripping tower (1), and introducing air for acidification stripping treatment, and absorbing the stripped gas with a sodium hydroxide solution; S5, secondary pH value adjustment: the waste liquid after acid stripping is passed into the adjustment tank (32) and the pH is adjusted to between 8 and 10 with alkali solution, and ozone is introduced; S6, coagulation and sedimentation: the oxidized wastewater is passed into a sedimentation tank (15), and a coagulant is added during the stirring process for coagulation and sedimentation. After coagulation, the wastewater enters a sedimentation tank and is left to stand for 15-120 minutes; S7, biological activated carbon treatment: the supernatant after precipitation enters the biological activated carbon treatment system, and is subjected to biological activated carbon treatment under the conditions of activated carbon filler, biofilm bacteria and air; S8, the treated waste liquid enters the return pool for returning to the production process or being discharged in compliance with the standards; The stripping tower (1) used in step S4 is provided with a plurality of waste liquid nozzles (2) distributed on the top, a plurality of packing layers (3) are provided at intervals above and below the waste liquid nozzles (2) in the stripping tower (1), and a corresponding blower (4) is connected to the outside under the bottom packing layer (3); a corresponding liquid collecting area (5) is provided at the bottom of the stripping tower (1), one side of the liquid collecting area (5) is connected to the outside with a corresponding liquid outlet main pipe (6), the liquid inlet end of the liquid outlet main pipe (6) is connected in parallel with a plurality of liquid outlet branch pipes (7), and the left and right sides of the liquid outlet branch pipes (7) are connected to the liquid outlet main pipe (6). The liquid outlet branch pipe (7) is installed side by side at right intervals in the liquid collecting area (5) of the stripping tower (1); the end of the liquid outlet branch pipe (7) not connected to the stripping tower (1) is coaxially sleeved with a corresponding ultrafine bubble outlet pipe (8); the ultrafine bubble outlet pipe (8) extends outwardly and is connected to an ultrafine bubble generator (29) on the outside; the end of the liquid outlet branch pipe (7) located in the stripping tower (1) is open-ended, and a corresponding flow divider (9) is coaxially fixedly installed; the open end of the liquid outlet branch pipe (7) is spherically arranged, and the end of the flow divider (9) located on one side of the ultrafine bubble outlet pipe (8) is conically arranged.

2. A method for treating cyanide-containing wastewater according to claim 1, characterized in that: The alkali solution in step S5 is sodium hydroxide or lime milk, and the coagulant in step S6 is a polymeric inorganic salt coagulant or a high molecular inorganic salt solution with a mass fraction of 10%-30%.

3. A method for treating cyanide-containing wastewater according to claim 1, characterized in that: The biological activated carbon treatment system of step S6 is an upflow or downflow reaction tank, the bottom of the tank is provided with a water distribution device and an aeration device, above the aeration device is an activated carbon filler layer (3), and the carbon loading volume accounts for 1 / 5-4 / 5 of the reactor volume; the biofilm forming bacteria are nitrite bacteria and nitrifying bacteria or cyanide-reducing bacteria, the biofilm forming method adopts artificial addition of bacteria to form biofilm or dynamic cultivation of natural biofilm, the gas-liquid ratio is 1-15:1, and the biological activated carbon treatment time is 30min-120min.

4. A method for treating cyanide-containing wastewater according to claim 1, characterized in that: The spherical end of the diverter (9) in the stripping tower (1) of step S4 is provided with a plurality of radially arranged positioning rods (10) distributed along the circumferential direction, and the two ends of the positioning rods (10) are fixedly mounted on the inner side wall of the liquid outlet branch pipe (7) and the spherical end of the diverter (9).

5. A method for treating cyanide-containing wastewater according to claim 4, characterized in that: The waste liquid nozzle (2) is connected to the waste liquid outlet of step S3 through a corresponding liquid extraction pump (11) and a liquid guide valve (12). The corresponding liquid outlet valve (13) and a liquid outlet pump (14) are installed on the liquid outlet main pipe (6). The liquid guide valve (12) and the liquid outlet valve (13) are automatic valves and are electrically connected to the control system together with the liquid extraction pump (11), the liquid outlet pump (14), the blower (4) and the ultra-fine bubble generator (29).

6. A method for treating cyanide-containing wastewater according to claim 1, characterized in that: The upper part of the precipitation tank (15) of step S6 is fixedly mounted with a corresponding sealing cover (16), and a feed pipe (17) and a liquid inlet pipe (18) are arranged on the sealing cover (16), and the middle side and bottom of the precipitation tank (15) are respectively provided with corresponding supernatant liquid outlet pipe (30) and discharge pipe (19); the lower side of the sealing cover (16) is rotatably mounted with a corresponding stirring shaft (20), and a plurality of staggered stirring rods (21) are fixedly mounted on the stirring shaft (20) from top to bottom, and a V-shaped stirring member (23) is mounted on the end of the stirring rod (21) through a sleeved tubular flexible member (22), and the V-shaped opening of the stirring member (23) is adjustable; the stirring member (23) and the stirring rod (21) are relatively rotatable. The inner side surfaces of the stirring member (23) are respectively provided with a matching trigger member (24) and a micro switch (25); when the V-shaped opening of the stirring member (23) is opened, the trigger member (24) fixedly mounted on the stirring member (23) moves toward the stirring rod (21) along with the end of the stirring member (23) and triggers the micro switch (25), thereby controlling the stirring shaft (20) to rotate in the opposite direction through electrical connection; a corresponding pressure sensor (31) is mounted on the stirring member (23) and embedded in the tubular flexible member (22); the detection end of the pressure sensor (31) abuts against the connection between the stirring member (23) and the tubular flexible member (22); when the pressure value detected by the pressure sensor (31) is greater than F1, the forward and reverse motor (26) stops.

7. A method for treating cyanide-containing wastewater according to claim 6, characterized in that: The liquid inlet pipe (18) is connected to the waste liquid outlet in step S5 through a corresponding intermediate pump and an intermediate valve.

8. A method for treating cyanide-containing wastewater according to claim 6, characterized in that: The stirring member (23) comprises two plate blades (2301) whose ends are hinged to each other, and the plate blades (2301) are respectively tangentially fixed to the tubular flexible member (22), and the tubular flexible member (22) is made of a deformable rubber material; when the two plate blades (2301) on the stirring member (23) are opened, the tubular flexible member (22) is stretched.

9. A method for treating cyanide-containing wastewater according to claim 6, characterized in that: The stirring shaft (20) is driven to rotate forward and reverse by a forward and reverse motor (26) installed above the sealing cover (16); when the micro switch (25) is triggered, the forward and reverse motor (26) rotates in the reverse direction.

10. A method for treating cyanide-containing wastewater according to claim 6, characterized in that: A corresponding mounting tube (27) is fixedly connected downwardly to the bottom side of the sealing cover (16) at a position corresponding to the stirring shaft (20), and the stirring shaft (20) is rotatably sleeved on the mounting tube (27) through a corresponding bearing; the sedimentation tank (15) is supported and installed by corresponding supporting legs (28); a corresponding closing cover is installed on the feed pipe (17) in an openable and closable manner; and corresponding feed valves, discharge valves and discharge valves are fixedly installed on the liquid inlet pipe (18), the supernatant liquid outlet pipe (30) and the discharge pipe (19), respectively.

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