Yellow phosphorus production sewage closed cycle treatment and recycling system

Abstract

The utility model provides a closed circulation treatment and recycling system for yellow phosphorus production sewage, which relates to the technical field of yellow phosphorus production equipment and comprises a sewage collecting mechanism, a composite gravity settling mechanism, a composite flocculation settling mechanism and a cooling mechanism, the device is characterized in that the composite gravity settling mechanism and the composite flocculation settling mechanism are both in a closed state, and the top of each mechanism is provided with an independent air exhaust cooling pipeline (1) and an air inlet pipe (2) which is ventilated in a one-way mode from outside to inside; a two-stage autonomous settling structure is arranged, so that the flowing path of sewage is effectively increased within a limited distance and space, and the autonomous settling time is prolonged; by utilizing the height difference between the filter (21) and the cooling water tank (27) and the negative pressure generated by the suction pipeline when the supplemented cooling water falls, the sewage is pumped out of the filter (21), and meanwhile, the closed spaces of the mechanisms are promoted to carry out gas flow and gas exchange, so that the interior of the closed structure is cooled.

Description

Technical Field

[0001] The utility model relates to the technical field of yellow phosphorus production equipment, in particular to a yellow phosphorus sewage treatment system. Background Art

[0002] The process of producing yellow phosphorus is to mix phosphate rock, silica and coke in a certain proportion, and then add them into the yellow phosphorus ore thermoelectric furnace. The mixed materials undergo oxidation-reduction reaction in the high-temperature electric furnace to form vapor-like elemental phosphorus; the elemental phosphorus and yellow phosphorus tail gas undergo a series of cleaning and impurity removal in the tail gas treatment equipment, and then transform into liquid phosphorus, and then go through a refining process to finally obtain the finished yellow phosphorus. In this process, a large amount of water is needed to cool the vapor-like phosphorus, remove particulate impurities in the tail gas, remove harmful components, isolate the air and cool down, so a large amount of sewage will inevitably be generated. The sewage contains many harmful components, such as phosphorus, sulfide, etc., which cannot be directly discharged and used, and must be purified first.

[0003] Since the above-mentioned sewage is produced after high-temperature yellow phosphorus tail gas is treated with water, its own temperature is relatively high, usually reaching about 60°C. It was originally cooled naturally after reaching the sedimentation tank during the purification process, or cooled with the aid of a cooling tower, and then recycled after reaching room temperature; but with the improvement of social requirements for environmental protection, companies have also realized that during the storage and cooling of high-temperature phosphorus-containing sewage in open-air sedimentation tanks, phosphorus, sulfur and other environmentally harmful substances will be emitted into the air with water vapor, causing air pollution; therefore, some phosphorus chemical companies will include reaction tanks, sedimentation tanks, and even slag tanks. The device or structure involving water is closed, such as the scheme recorded in 2019200886491, to prevent air pollution, but this also leads to slow cooling of the water, requiring extended working hours and the volume of related equipment, or the need to install additional heat exchange cooling devices, such as the scheme recorded in 2020218929742, which increases energy consumption and sewage treatment costs. Summary of the invention

[0004] In order to solve the above problems, the utility model provides a closed-loop treatment and recycling system for yellow phosphorus production wastewater.

[0005] The utility model adopts the following technical scheme: a closed-loop treatment and recycling system for yellow phosphorus production wastewater, comprising the following components: a wastewater collection mechanism, a composite gravity sedimentation mechanism, a composite flocculation sedimentation mechanism, and a cooling mechanism, characterized in that: the composite gravity sedimentation mechanism and the composite flocculation sedimentation mechanism are both in a closed state, and the top of each mechanism is provided with an independent air extraction cooling pipeline 1 and an air inlet pipe 2 for one-way ventilation from outside to inside;

[0006] The sewage collection mechanism includes a water diversion sealed pipe 3 and a corresponding sewage pump 4. The water diversion sealed pipe 3 is respectively connected to the sewage outlets of the scrubber 5, the phosphorus receiving tank 6, the mud phosphorus recovery unit 7, and the yellow phosphorus refining unit 8. The water diversion sealed pipe 3 is connected to the grid pool 9 after being collected. The grid pool 9 is provided with an inclined impurity removal grid 10, and the pool body is divided into two parts. The phosphorus-containing sewage with large volume of suspended impurities removed is temporarily stored in the right pool body of the grid pool 9. The bottom and side walls of the grid pool 9 are equipped with stirring devices to keep the sewage flowing and avoid sedimentation. The impurity removal grid 10 is provided with a rotary cleaning device to collect the separated suspended impurities.

[0007] In addition, the sewage collection mechanism also includes a water volume regulating pool 11 arranged behind the grid pool 9, which is capable of accommodating the uneven inflow of sewage and balancing the uniform outflow of sewage. At the same time, a fan 12 is arranged above the water volume regulating pool 11, and the air outlet of the fan 12 extends into the bottom of the water volume regulating pool 11, and the air outlets are evenly distributed to transfer oxygen in the air to the sewage in the pool to supply the oxygen required for aerobic biological metabolism, and at the same time, the sewage in the pool is fully and evenly mixed;

[0008] The composite gravity sedimentation mechanism is arranged behind the water regulating tank 11, which is a hollow container with a rectangular shape as a whole, and is divided into an impurity sedimentation area 13, a sewage inlet area 14, a slow sedimentation area 15, and a clean water overflow area 16 from bottom to top;

[0009] The impurity settling area 13 is provided with a plurality of sludge hoppers 13-1 arranged in sequence, the lower end of which is connected to a sewage pipe and a sludge pump and extends to a sludge phosphorus storage tank; a sewage inlet 14-1 is provided on the side wall above the impurity settling area 13, and the area directly opposite to the sewage inlet 14-1 is the sewage inlet area 14, in which a plurality of baffles 14-2 are vertically provided to slow down the flow rate of sewage and help particle settling, and the two ends of the baffles 14-2 are fixed on the corresponding side walls, and the plate body is fixed to the bottom of the container through a bracket;

[0010] Above the sewage inlet area 14, a slow settling area 15 is provided, and a fixed number of slow flow plates 15-1 which are parallel to and inclined with each other and are consistent with the baffles 14-2 are provided on the side wall of the container. A gap is left between the lower end of the first inclined slow flow plate 15-1 close to the sewage inlet 14-1 and the corresponding baffle 14-2, and the lower end of the second slow flow plate 15-1 is connected to the corresponding baffle 14-2. The installation structure of the third slow flow plate 15-1 is the same as that of the first, and the installation structure of the fourth slow flow plate 15-1 is the same as that of the first. The second block is the same, and so on, forming a structure in which the slow flow plate 15-1 and the baffle plate 14-2 are connected at intervals; the sewage enters from the bottom of the slow flow plate 15-1, and slowly flows obliquely upward through the channel between the slow flow plates 15-1. Under the combined effect of the slower flow rate and the longer flow channel, the impurities in the sewage settle on the surface of the slow flow plate 15-1 and accumulate. When the gravity accumulates to a level greater than the resistance of the slow flow plate 15-1 and the upward lifting force of the sewage, the impurities slide into the sludge hopper 13-1;

[0011] Above the slow settling area 15 is a clean water overflow area 16. A plurality of parallel water chutes 16-1 are arranged on the water surface of the clean water overflow area 16. A screen is arranged on the outer edge of the water chutes 16-1. The water below the water chutes 16-1 is collected into a water delivery pipe, which is connected to a composite flocculation settling mechanism.

[0012] The composite flocculation and sedimentation mechanism includes a dosing device 17, a coagulation tank 18, a flocculation tank 19, a filter press, and an air flotation tank 20, and the rear of the air flotation tank 20 is connected to a cooling mechanism;

[0013] The cooling mechanism includes a filter 21, a water extraction pipe 22, an air extraction pipe 23, a temporary water tank 24, a downpipe 25, a cold water supply pipe 26, a cooling water tank 27, a radiator 28, and a water supply pump 29; the height of the filter 21 is higher than the cooling water tank 27, the water extraction pipe 22 is connected to the water outlet pipe of the filter 21, and the air extraction pipe 23 is connected to the independent air extraction cooling pipelines 1 on the composite gravity sedimentation mechanism and the composite flocculation sedimentation mechanism; the other end of the water extraction pipe 22 is located inside the temporary water tank 24, and its port extends into the downpipe 25 connected to the bottom of the temporary water tank 24, and the port of the water extraction pipe 22 is set to be straight The end of the suction pipe 23 also extends into the downpipe 25; cooling water is pre-set in the temporary water tank 24, the water level exceeds the center line of the temporary water tank 24, and the downpipe 25 connected thereto is also filled with cooling water, so that the ports of the suction pipe 22 and the suction pipe 23 are kept immersed in water at any time and isolated from the outside world; the cold water replenishment pipe 26 is connected from the top of the temporary water tank 24, and its water intake under normal working conditions needs to keep the water level in the temporary water tank 24 balanced; the cooling water tank 27 is set in an open form to facilitate heat dissipation, and the radiator 28 is set in the cooling water tank 27 to assist in accelerating the cooling of the treated sewage.

[0014] Preferably, the front side of the slow flow plate 15 - 1 of the slow settling area 15 in the composite gravity settling mechanism faces away from the sewage inlet 14 - 1 , so as to reduce the impact of sewage on the impurities deposited on the slow flow plate 15 - 1 .

[0015] Preferably, the inclination angle of the slow flow plate 15-1 is 45°-60° with respect to the horizontal plane of the entire mechanism, the length of the slow flow plate 15-1 is greater than or equal to 100 cm, and the distance between any two slow flow plates 15-1 is 6-10 cm.

[0016] Preferably, the height of the clean water overflow area 16 is 70-80 cm; the height of the slow settling area 15 is 70-80 cm; and the height of the impurity settling area 13 is 90-100 cm.

[0017] Preferably, the inner diameter of the downpipe 25 is 3 times or more of the inner diameter of the water pumping pipe 22 .

[0018] Preferably, the installation height difference between the filter 21 and the cooling water tank 27 needs to ensure that the energy consumed by the sewage to pass through the filter 21 is less than or equal to the difference in potential energy of the sewage due to the height difference between the filter 21 and the cooling water tank 27, that is, the potential energy of the sewage due to the height difference must at least ensure that it can pass through the filter 21. Beneficial Effects

[0019] ① The utility model improves the purification efficiency and purification effect of yellow phosphorus sewage by optimizing the design of the key gravity sedimentation and filtration cooling mechanism in the treatment of yellow phosphorus sewage, accelerates the cooling of sewage, and reduces the cost of sewage treatment.

[0020] ② The present application sets up a two-level autonomous sedimentation structure in the gravity sedimentation mechanism, namely the impurity sedimentation area 13 structure at the bottom and the slow sedimentation area 15 structure in the middle, which effectively increases the flow distance of the sewage within a limited distance and space, increases its autonomous sedimentation time, and removes the impurity particles in the sewage to the greatest extent.

[0021] ③ In response to the problem of rising sewage temperature caused by the existing yellow phosphorus sewage purification system that must remain closed, the present application utilizes the height difference between the filter 21 and the cooling water pool 27 and the negative pressure generated by the suction pipe when the supplementary cooling water falls. While extracting the sewage from the filter 21, it can also promote a certain degree of gas flow in the closed space of each mechanism and gas exchange with the outside world, thereby cooling the interior of the closed structure without adding additional exhaust equipment, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the closed-loop treatment and recycling system for yellow phosphorus production wastewater described in this application.

[0023] Figure 2 It is a structural schematic diagram of the composite gravity sedimentation mechanism.

[0024] Figure 3 It is a structural schematic diagram of the cooling mechanism.

[0025] In the figure: exhaust cooling pipeline 1, air inlet pipe 2, water diversion sealing pipeline 3, sewage pump 4, scrubber 5, phosphorus receiving tank 6, sludge phosphorus recovery unit 7, yellow phosphorus refining unit 8, grid pool 9, impurity removal grid 10, water volume regulating tank 11, fan 12, impurity settling area 13, sludge hopper 13-1, sewage inlet area 14, sewage inlet 14-1, baffle 14-2, slow settling area 15, slow flow plate 15-1, clean water overflow area 16, downspout 16-1, dosing device 17, coagulation tank 18, flocculation tank 19, flotation tank 20, filter 21, water extraction pipe 22, exhaust pipe 23, temporary water tank 24, downspout 25, cold water make-up pipe 26, cooling water tank 27, radiator 28, make-up pump 29. DETAILED DESCRIPTION

[0026] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0027] refer to Figure 1 This embodiment describes a closed-loop treatment and recycling system for yellow phosphorus production wastewater, which includes the following components: a wastewater collection mechanism, a composite gravity sedimentation mechanism, a composite flocculation sedimentation mechanism, and a cooling mechanism; the composite gravity sedimentation mechanism and the composite flocculation sedimentation mechanism are both in a closed state, and each mechanism is provided with an independent exhaust cooling pipeline 1 and an air inlet pipe 2 for one-way ventilation from outside to inside on the top.

[0028] The sewage collection mechanism includes a water diversion sealed pipe 3 and a corresponding sewage pump 4. The water diversion sealed pipe 3 is respectively connected to the sewage outlets of the scrubbing tower 5, the phosphorus receiving tank 6, the mud phosphorus recovery unit 7, and the yellow phosphorus refining unit 8. The water diversion sealed pipe 3 is connected to the grid pool 9 after being collected. An inclined impurity removal grid 10 is arranged in the grid pool 9, and the pool body is divided into two parts. The phosphorus-containing sewage with large volume suspended impurities removed is temporarily stored in the right pool body of the grid pool 9. A stirring device is installed on the bottom and side wall to keep the sewage flowing and avoid sedimentation. A rotary cleaning device is arranged on the impurity removal grid 10 to collect the separated suspended impurities.

[0029] In addition, the sewage collection mechanism also includes a water regulating tank 11 arranged behind the grid tank 9, which has the function of accommodating the uneven inflow of sewage and balancing the uniform outflow of sewage. At the same time, a fan 12 is arranged above the water regulating tank 11, and the air outlet of the fan 12 extends into the bottom of the water regulating tank 11, and the air outlets are evenly distributed to transfer oxygen in the air to the sewage in the tank to supply the oxygen required for aerobic biological metabolism, and at the same time, the sewage in the tank is fully and evenly mixed.

[0030] The composite gravity sedimentation mechanism is arranged behind the water regulating tank 11, which is a hollow container with a rectangular shape as a whole, and is divided into an impurity sedimentation area 13, a sewage inlet area 14, a slow sedimentation area 15, and a clean water overflow area 16 from bottom to top; the impurity sedimentation area 13 is provided with a plurality of sludge hoppers 13-1 arranged in sequence, the lower end of which is connected to the sewage pipe and the sludge pump, and extends to the sludge phosphorus storage tank; a sewage inlet 14-1 is arranged on the side wall above the impurity sedimentation area 13, and the area directly facing the sewage inlet 14-1 is The sewage inlet area 14 has a plurality of baffles 14-2 arranged vertically in this area to slow down the flow rate of sewage and help particle sedimentation. The two ends of the baffles 14-2 are fixed on the corresponding side walls, and the plate body is fixed to the bottom of the container through a bracket. Above the sewage inlet area 14, a slow sedimentation area 15 is arranged. The same number of slow flow plates 15-1 as the baffles 14-2, which are parallel and inclined to each other, are fixed on the side wall of the container. The first inclined slow flow plate 15-1 near the sewage inlet 14-1 is arranged at the bottom of the container. There is a gap between the lower end of the second slow flow plate 15-1 and the corresponding baffle 14-2, the lower end of the second slow flow plate 15-1 is connected to the corresponding baffle 14-2, the installation structure of the third block is the same as the first block, the installation structure of the fourth block is the same as the second block, and so on, forming a structure in which the slow flow plate 15-1 and the baffle 14-2 are connected at intervals; the sewage enters from the bottom of the slow flow plate 15-1, and slowly flows obliquely upward through the channel between the slow flow plates 15-1, and the slower flow rate and the longer flow channel are used together. Under the action, impurities in the sewage settle on the surface of the slow flow plate 15-1 and accumulate. When the gravity accumulates to be greater than the resistance of the slow flow plate 15-1 and the upward lifting force of the sewage, the impurities slide into the sludge hopper 13-1; above the slow settling area 15 belongs to the clean water overflow area 16, and a plurality of parallel arranged downspouts 16-1 are arranged on the water surface of the clean water overflow area 16, and a screen is arranged on the outer edge of the downspout 16-1, and the water below the downspout 16-1 is collected to the water pipe, and the water pipe is connected to the composite flocculation sedimentation mechanism.

[0031] The composite flocculation and sedimentation mechanism comprises a dosing device 17, a coagulation tank 18, a flocculation tank 19, a filter press and an air flotation tank 20, and the rear of the air flotation tank 20 is connected to a cooling mechanism.

[0032] refer to Figure 3The cooling mechanism includes a filter 21, a water extraction pipe 22, an air extraction pipe 23, a temporary water tank 24, a downpipe 25, a cold water supply pipe 26, a cooling water tank 27, a radiator 28, and a water supply pump 29; the height of the filter 21 is higher than the cooling water tank 27, the water extraction pipe 22 is connected to the water outlet pipe of the filter 21, and the air extraction pipe 23 is connected to the independent air extraction cooling pipelines 1 on the composite gravity sedimentation mechanism and the composite flocculation sedimentation mechanism; the other end of the water extraction pipe 22 is located inside the temporary water tank 24, and its port extends into the downpipe 25 connected to the bottom of the temporary water tank 24, and the port of the water extraction pipe 22 is set to be straight The end of the suction pipe 23 also extends into the downpipe 25; cooling water is pre-set in the temporary water tank 24, the water level exceeds the center line of the temporary water tank 24, and the downpipe 25 connected thereto is also filled with cooling water, so that the ports of the suction pipe 22 and the suction pipe 23 are kept immersed in water at any time and isolated from the outside world; the cold water replenishment pipe 26 is connected from the top of the temporary water tank 24, and its water intake under normal working conditions needs to keep the water level in the temporary water tank 24 balanced; the cooling water tank 27 is set in an open form to facilitate heat dissipation, and the radiator 28 is set in the cooling water tank 27 to assist in accelerating the cooling of the treated sewage.

[0033] When working, first close the bottom of the downpipe 25, and inject the cooling water in the cooling water pool 27 into the temporary water tank 24 and the downpipe 25 through the cold water replenishment pipe 26 via the water replenishment pump 29. After the water level in the temporary water tank 24 reaches the center line and the ports of the water pumping pipe 22 and the air extraction pipe 23 are immersed and closed, open the bottom of the downpipe 25, and the water replenishment pump 29 continues to work to replenish water. The water in the temporary water tank 24 flows downward through the downpipe 25 into the cooling water pool 27. In the process of water falling, the water pumping pipe 22 and the air extraction pipe 23 are sucked, so that the water in the pipes is The negative pressure is generated, firstly, to force the sewage to pass through the filter 21 and enter the water extraction pipe 22, and finally flow into the cooling water pool 27 for cooling; secondly, the negative pressure generated by the air extraction pipe 23 will also act on the air extraction cooling pipeline 1 and the air inlet pipe 2 connected thereto and arranged on the composite gravity sedimentation mechanism and the composite flocculation sedimentation mechanism, thereby forcing each mechanism to carry out a certain degree of gas flow and gas exchange with the outside world, thereby cooling the closed structure inside the composite gravity sedimentation mechanism and the composite flocculation sedimentation mechanism, accelerating the cooling of the sewage and reducing the sewage treatment cost.

[0034] In addition, refer to Figure 2The front of the slow flow plate 15-1 of the slow settling area 15 in the composite gravity sedimentation mechanism is facing away from the sewage inlet 14-1, reducing the impact of sewage on impurities deposited on the slow flow plate 15-1; the inclination angle of the slow flow plate 15-1 is 45° with the horizontal plane of the entire mechanism, the length of the slow flow plate 15-1 is greater than or equal to 100 cm, and the distance between any two slow flow plates 15-1 is 10 cm; the height of the clean water overflow area 16 is 80 cm; the height of the slow settling area 15 is 80 cm; the height of the impurity sedimentation area 13 is 100 cm; the inner diameter of the downpipe 25 is 3 times the inner diameter of the suction pipe 22.

Claims

1. A closed-loop treatment and recycling system for yellow phosphorus production wastewater, comprising the following components: a wastewater collection mechanism, a composite gravity sedimentation mechanism, a composite flocculation sedimentation mechanism, and a cooling mechanism, characterized in that: The composite gravity sedimentation mechanism and the composite flocculation sedimentation mechanism are both in a closed state, and each mechanism is provided with an independent air extraction cooling pipeline (1) and an air inlet pipe (2) for one-way ventilation from outside to inside on the top; The sewage collection mechanism comprises a water diversion sealed pipe (3) and a corresponding sewage pump (4). The water diversion sealed pipe (3) is respectively connected to the sewage outlets of the scrubber (5), the phosphorus receiving tank (6), the sludge phosphorus recovery unit (7), and the yellow phosphorus refining unit (8). The water diversion sealed pipe (3) is connected to the grid pool (9) after being collected. An inclined impurity removal grid (10) is arranged in the grid pool (9) to divide the pool into two parts. The phosphorus-containing sewage from which large-volume suspended impurities are removed is temporarily stored in the right pool of the grid pool (9). A stirring device is installed on the bottom and side wall of the grid pool to keep the sewage flowing and avoid sedimentation. A rotary cleaning device is arranged on the impurity removal grid (10); In addition, the sewage collection mechanism further comprises a water volume regulating pool (11) arranged behind the grid pool (9), which is capable of accommodating uneven inflow of sewage and balancing uniform outflow of sewage. At the same time, a fan (12) is arranged above the water volume regulating pool (11), and the air outlet of the fan (12) extends into the bottom of the water volume regulating pool (11), and the air outlet holes are evenly distributed; The composite gravity sedimentation mechanism is arranged behind the water volume regulating tank (11), which is a hollow container with an overall rectangular shape and is divided into an impurity sedimentation area (13), a sewage inlet area (14), a slow sedimentation area (15), and a clean water overflow area (16) from bottom to top; The impurity settling area (13) is provided with a plurality of sludge hoppers (13-1) arranged in sequence, the lower ends of which are connected to a sewage pipe and a sludge pump and extend to a sludge phosphorus storage tank; a sewage inlet (14-1) is provided on the side wall above the impurity settling area (13); the area directly opposite the sewage inlet (14-1) is the sewage inlet area (14); a plurality of baffles (14-2) are vertically provided in this area to slow down the flow rate of sewage and facilitate particle settling; the two ends of the baffles (14-2) are fixed on the corresponding side walls, and the baffle body is fixed to the bottom of the container through a bracket; A slow settling area (15) is provided above the sewage inlet area (14), and a number of slow flow plates (15-1) which are the same as the baffles (14-2) and are arranged parallel to each other and inclined are fixed on the side wall of the container; a gap is left between the lower end of the first inclined slow flow plate (15-1) close to the sewage inlet (14-1) and the corresponding baffle (14-2); the lower end of the second slow flow plate (15-1) is connected to the corresponding baffle (14-2); the installation structure of the third slow flow plate is the same as the first; the installation structure of the fourth slow flow plate is the same as the second; and so on, thereby forming a structure in which the slow flow plates (15-1) and the baffles (14-2) are connected at intervals; Above the slow settling area (15) is a clean water overflow area (16), a plurality of parallel-arranged water troughs (16-1) are arranged on the water surface of the clean water overflow area (16), a screen is arranged on the outer edge of the water trough (16-1), and water below the water trough (16-1) is collected into a water delivery pipe, which is connected to a composite flocculation settling mechanism; The composite flocculation and sedimentation mechanism comprises a dosing device (17), a coagulation tank (18), a flocculation tank (19), a filter press and an air flotation tank (20), and the rear of the air flotation tank (20) is connected to a cooling mechanism; The cooling mechanism comprises a filter (21), a water extraction pipe (22), an air extraction pipe (23), a temporary water tank (24), a downpipe (25), a cold water supply pipe (26), a cooling water pool (27), a radiator (28), and a water supply pump (29); the height of the filter (21) is higher than the cooling water pool (27); the water extraction pipe (22) is connected to the water outlet pipe of the filter (21); the air extraction pipe (23) is connected to the independent air extraction cooling pipes (26) on the composite gravity sedimentation mechanism and the composite flocculation sedimentation mechanism. 1) are connected; the other end of the water extraction pipe (22) is located inside the temporary water tank (24), and its end extends into a downpipe (25) connected to the bottom of the temporary water tank (24), and the end of the water extraction pipe (22) is configured to be a trumpet shape with a gradually increasing diameter, and the end of the air extraction pipe (23) also extends into the downpipe (25); the cold water replenishment pipe (26) is connected from the top of the temporary water tank (24), the cooling water pool (27) is configured to be open, and the radiator (28) is arranged in the cooling water pool (27).

2. The closed-loop treatment and recycling system for yellow phosphorus production wastewater according to claim 1 is characterized in that: The front side of the slow flow plate (15-1) of the slow settling area (15) in the composite gravity settling mechanism faces away from the sewage inlet (14-1).

3. The closed-loop treatment and recycling system for yellow phosphorus production wastewater according to claim 1 is characterized in that: The inclination angle of the slow flow plate (15-1) is 45°-60° with respect to the horizontal plane of the entire mechanism, the length of the slow flow plate (15-1) is greater than or equal to 100 cm, and the distance between any two slow flow plates (15-1) is 6-10 cm.

4. The closed-loop treatment and recycling system for yellow phosphorus production wastewater according to claim 1 is characterized in that: The height of the clean water overflow zone (16) is 70-80 cm; the height of the slow settling zone (15) is 70-80 cm; and the height of the impurity settling zone (13) is 90-100 cm.

5. The closed-loop treatment and recycling system for yellow phosphorus production wastewater according to claim 1 is characterized in that: The inner diameter of the downpipe (25) is 3 times or more the inner diameter of the water pumping pipe (22).

6. The closed-loop treatment and recycling system for yellow phosphorus production wastewater according to claim 1 is characterized in that: There is an installation height difference between the filter (21) and the cooling water pool (27), and the energy consumed by the sewage passing through the filter (21) is less than or equal to the difference in potential energy of the sewage due to the height difference between the filter (21) and the cooling water pool (27).

Images