A wet-process phosphoric acid concentration absorption circulation system

Abstract

This utility model relates to the field of wet-process phosphoric acid production technology, specifically a wet-process phosphoric acid concentration and absorption circulation system, including a tower body and a circulation tank assembly. The tower body comprises a monofluorinated absorption tower and a difluorinated absorption tower arranged in series. The circulation tank assembly includes a monofluorinated absorption circulation tank, a difluorinated absorption circulation tank, a fluorosilicic acid intermediate tank, connecting pipes, an overflow pipe, and level gauges, with the level gauges installed on the monofluorinated and difluorinated absorption circulation tanks. In terms of production continuity, this wet-process phosphoric acid concentration and absorption circulation system, through its innovative structural design, changes the traditional intermittent acid output mode. The overflow pipe continuously introduces qualified fluorosilicic acid from the monofluorinated absorption circulation tank into the fluorosilicic acid intermediate tank, and then the axial flow pump transports it to the finished product tank, achieving continuous production of fluorosilicic acid products. This avoids production interruptions caused by manual inspection and control of emissions, making the entire production process smoother and more efficient.

Description

Technical Field

[0001] This utility model relates to the field of wet-process phosphoric acid production technology, and more specifically, to a wet-process phosphoric acid concentration absorption and circulation system. Background Technology

[0002] In the field of wet-process phosphoric acid production technology, the treatment of waste gas from the phosphoric acid concentration stage has always been a key factor restricting the industry's green and efficient development. During the concentration process, about 80% of the fluorine will enter the waste gas in the form of SiF4, HF, etc. (the average fluorine content of phosphate rock is 3%-4%). ​​If not properly recovered, not only will more than one million tons of fluorine resources be lost annually, but it will also cause the dual problems of equipment corrosion and environmental pollution.

[0003] Currently, most industrial methods for absorbing fluorine-containing waste gas under vacuum conditions using a cascade countercurrent spraying method to produce low-concentration fluorosilicic acid products. This method employs a two-stage absorption structure of a "first fluorine absorption tower + second fluorine absorption tower," with the fluorine-containing waste gas being treated in stages through the first and second fluorine absorption circulation tanks. While this device has made some progress in fluorine resource recovery, its core drawback lies in the fact that the first fluorine absorption circulation tank uses an intermittent acid discharge mode, requiring manual monitoring of concentration and control of emissions, resulting in frequent interruptions in the production of fluorosilicic acid products (16wt%). Actual operation data shows that the device needs to be shut down for inspection 1-2 times every 8 hours, with each operation taking 20-30 minutes, reducing the annual effective operating time by about 9%. More importantly, the liquid level in the circulation tank fluctuates by 30%-40% during intermittent discharge. When the liquid level is below the critical value, it is very easy to cause the system to break the vacuum (the vacuum level rises sharply from -0.09MPa to below -0.03MPa), forcing the concentration process to stop. A single failure can result in a production capacity loss of more than 50 tons per day.

[0004] Furthermore, the two-stage absorption circulation tanks of this device employ independent water replenishment systems and lack a liquid level linkage adjustment mechanism. The liquid level in the first fluoride absorption circulation tank mainly relies on the natural overflow replenishment from the second fluoride absorption circulation tank, with the replenishment volume fluctuating within a range of ±2m. 3 The low concentration of fluorosilicic acid (fluorosilicic acid) caused a deviation of over 2wt% in the concentration, resulting in a product qualification rate of only 82%-85%. Furthermore, the lack of a dedicated intermediate buffer structure in the circulation tank meant that fluorosilicic acid remained in the tank for up to 4 hours, with a foam layer thickness of 50-80mm. This severely interfered with the accuracy of the level gauge (error ±150mm), further exacerbating operational risks. Utility Model Content

[0005] The purpose of this invention is to provide a wet-process phosphoric acid concentration absorption and circulation system to solve the problem mentioned in the background art that the first fluorine absorption circulation tank adopts an intermittent acid discharge mode, which requires manual monitoring of concentration and manual control of discharge, resulting in frequent interruptions in the production of fluorosilicic acid product (16wt%).

[0006] To achieve the above objectives, this utility model provides a wet-process phosphoric acid concentration absorption and circulation system, including a tower body and a circulation tank assembly; the tower body includes a monofluoride absorption tower and a difluoride absorption tower arranged in series, and the circulation tank assembly includes a monofluoride absorption circulation tank, a difluoride absorption circulation tank, a fluorosilicic acid intermediate tank, a connecting pipe, an overflow pipe, and a level gauge, wherein the level gauge is installed on the monofluoride absorption circulation tank and the difluoride absorption circulation tank;

[0007] The monofluorine absorption circulation tank and the difluorine absorption circulation tank are connected by a connecting pipe. The two ends of the connecting pipe are located in the upper region of the monofluorine absorption circulation tank and the difluorine absorption circulation tank, and the end closer to the difluorine absorption circulation tank is higher than the end closer to the monofluorine absorption circulation tank.

[0008] One end of the overflow pipe is connected to the upper part of the fluorine absorption circulation tank, and the other end is connected to the fluorosilicic acid intermediate tank, with the end closer to the fluorine absorption circulation tank being higher than the end closer to the fluorosilicic acid intermediate tank.

[0009] This setup, by installing level gauges on both the monofluoride absorption circulation tank and the difluoride absorption circulation tank, allows for simultaneous monitoring of the liquid levels in both tanks, facilitating precise control of the liquid level balance. The height difference design at both ends of the connecting pipe utilizes gravity to allow the liquid in the difluoride absorption circulation tank to flow naturally into the monofluoride absorption circulation tank, achieving automatic replenishment; the height difference design of the overflow pipe, on the other hand, uses gravity to allow the qualified liquid in the monofluoride absorption circulation tank to automatically flow into the fluorosilicic acid intermediate tank.

[0010] Preferably, the absorbent in the monofluoride absorption circulation tank and the difluoride absorption circulation tank is fluorosilicic acid, and the fluorosilicic acid product is produced from the monofluoride absorption circulation tank.

[0011] This setting clearly defines that the absorbent in the monofluoride absorption circulation tank and the difluoride absorption circulation tank is fluorosilicic acid, and that the fluorosilicic acid product is only produced from the monofluoride absorption circulation tank, thus determining the source of the product and the properties of the absorbent.

[0012] Preferably, the fluorine absorption circulation tank has an overflow port and a connection port on both sides, the fluorosilicic acid intermediate tank has an overflow port on one side, and the difluorine absorption circulation tank has a connection port on one side. The two ends of the connecting pipe are respectively connected to the overflow port and the connection port of the fluorine absorption circulation tank, and the two ends of the overflow pipe are respectively connected to the overflow port of the fluorine absorption circulation tank and the overflow port of the fluorosilicic acid intermediate tank.

[0013] This setup standardizes the connection method of each component by setting specific interfaces and connecting the connecting pipes and overflow pipes to the corresponding interfaces, ensuring that the liquid flows between the tanks along a predetermined path.

[0014] Preferably, the top height of the fluorosilicic acid intermediate tank is higher than the top height of the fluorine absorption circulation tank, and an axial flow pump is connected to the bottom of the fluorosilicic acid intermediate tank. The fluorine absorption circulation tank introduces qualified fluorosilicic acid into the fluorosilicic acid intermediate tank through an overflow pipe. The axial flow pump is used to transport the fluorosilicic acid in the fluorosilicic acid intermediate tank to the finished product tank.

[0015] This feature is designed so that the top of the intermediate fluorosilicic acid tank is higher than that of the primary fluorine absorption and circulation tank, using the height difference to prevent backflow of liquid in the intermediate tank; the axial flow pump provides power for transporting fluorosilicic acid from the intermediate tank to the finished product tank.

[0016] Preferably, the difluoride absorption circulation tank is externally connected to a water supply device, and a flow meter is installed on the water supply pipe of the water supply device. The flow rate of the water supply device is controlled by the flow meter to be between 3-10 m³ / h. 3 / h.

[0017] This device is designed to replenish the liquid in the difluoride absorption circulation tank. The flow meter can precisely control the amount of water replenished, ensuring that the amount of water replenished matches the system consumption.

[0018] Preferably, the installation position of the connecting pipe on the monofluoride absorption circulation tank and the difluoride absorption circulation tank is located in the range of 5 / 10 to 9 / 10 of the tank height, the vertical height difference between the connection port of the monofluoride absorption circulation tank and the connection port of the difluoride absorption circulation tank is 5cm-30cm, and the vertical height difference between the overflow port of the monofluoride absorption circulation tank and the connection port of the difluoride absorption circulation tank is 10cm-50cm.

[0019] This setting, with the connecting pipe installed in a specific section at the top of the circulation tank and the vertical height difference of each interface, further optimizes the natural flow conditions of the liquid, ensuring smooth liquid replenishment and overflow.

[0020] Preferably, the overflow pipe is equipped with a regulating valve, which is selected from gate valve, globe valve, check valve, butterfly valve, ball valve, plug valve, control valve or diaphragm valve. The inner diameter of the overflow pipe is φ10cm-φ30cm, and the material is selected from polyethylene, polyvinyl chloride, polypropylene, ABS plastic, polytetrafluoroethylene or polyphenylene sulfide. The fluorosilicic acid intermediate tank has a built-in agitator with a working speed of 30-100r / min. The fluorosilicic acid intermediate tank is made of PP material with an inner diameter of φ3000mm and a height of 2500mm.

[0021] This setting includes a regulating valve to control the flow rate and velocity of the liquid in the overflow pipe; the overflow pipe with a specific inner diameter and material ensures smooth liquid flow and is corrosion-resistant and durable; the stirrer can agitate the liquid in the fluorosilicic acid intermediate tank to prevent sedimentation; the fluorosilicic acid intermediate tank with specific materials and dimensions is adapted to its working environment and capacity requirements.

[0022] Preferably, both the monofluorine absorption tower and the difluorine absorption circulation tank are equipped with spray devices. The monofluorine absorption tower is connected to the monofluorine absorption circulation tank through a circulation pipeline, and a liquid pump and valves are installed on the pipeline. The top of the monofluorine absorption tower is connected to the difluorine absorption tower through a pipeline. The difluorine absorption tower is connected to the difluorine absorption circulation tank through a circulation pipeline, and a liquid pump and valves are installed on the pipeline. A vacuum pipe is connected to the top of the difluorine absorption tower.

[0023] The spray devices inside the monofluorinated and difluorinated absorption towers can evenly spray the liquid in the circulation tank, enhancing the contact with the waste gas; the circulation pipeline and related equipment enable the liquid to circulate between the tower body and the circulation tank, improving absorption efficiency; the vacuum pipe creates a vacuum environment for the difluorinated absorption tower, which is beneficial for waste gas treatment.

[0024] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0025] In terms of production continuity, this wet-process phosphoric acid concentration and absorption circulation system has changed the traditional intermittent acid output mode through innovative structural design. By using an overflow pipe to continuously introduce qualified fluorosilicic acid from the monofluorinated absorption circulation tank into the intermediate fluorosilicic acid tank, and then transporting it to the finished product tank by an axial flow pump, continuous production of fluorosilicic acid is achieved. This avoids production interruptions caused by manual inspection and control of emissions, making the entire production process smoother and more efficient.

[0026] Regarding system stability, the height difference between the connecting pipe and the overflow pipe, along with the external water supply device with a flow meter connected to the difluoropolymer absorption circulation tank, forms an effective liquid level linkage regulation mechanism. This ensures a stable liquid level in the monofluoropolymer absorption circulation tank, significantly reducing the risk of vacuum breakage caused by liquid level fluctuations, guaranteeing the stable operation of the concentration process, and minimizing losses due to shutdowns caused by malfunctions. Simultaneously, a stable liquid level environment also facilitates the control of fluorosilicic acid concentration, improving the product qualification rate.

[0027] In terms of ease of operation and safety, the fluorosilicic acid intermediate tank provides a good buffer, reducing the interference of the foam layer on the accuracy of the level gauge and making level monitoring more accurate and reliable. Furthermore, the rational configuration of valves, pumps, and other components on various pipelines and devices simplifies system operation, reduces the difficulty and error of manual operation, and improves the safety of the production process.

[0028] From the perspective of resource recycling, this system optimizes the absorption process of fluorine-containing waste gas. The coordinated operation of the two-stage absorption tower and the circulation tank improves the absorption efficiency of fluorine, enabling more fluorine resources to be converted into valuable fluorosilicic acid products, achieving effective resource recovery, and meeting the requirements of green chemical industry and sustainable development. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0030] Figure 2 This is one of the partial structural schematic diagrams of this utility model;

[0031] Figure 3 This is the second partial structural schematic diagram of the present utility model;

[0032] The meanings of the labels in the diagram are as follows:

[0033] 1. Fluorine absorption tower; 2. Spraying device; 3. Agitator; 4. Fluorosilicic acid intermediate tank; 5. Axial flow pump; 6. Fluorosilicic acid intermediate tank overflow port; 7. Overflow pipe; 8. Regulating valve; 9. Fluorine absorption circulation tank overflow port; 10. Fluorine absorption circulation tank; 11. Level gauge; 12. Fluorine absorption circulation tank connection port; 13. Connecting pipe; 14. Difluorine absorption circulation tank connection port; 15. Difluorine absorption tower; 16. Difluorine absorption circulation tank; 17. Valve; 18. Flow meter; 19. Water replenishment device. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0035] This invention provides a wet-process phosphoric acid concentration and absorption recycling system, such as... Figure 1 , Figure 2 , Figure 3 As shown, it includes a tower body and a circulation tank assembly; the tower body includes a monofluoride absorption tower 1 and a difluoride absorption tower 15 arranged in series, and the circulation tank assembly includes a monofluoride absorption circulation tank 10, a difluoride absorption circulation tank 16, a fluorosilicic acid intermediate tank 4, a connecting pipe 13, an overflow pipe 7, and a level gauge 11, which is installed on the monofluoride absorption circulation tank 10 and the difluoride absorption circulation tank 16.

[0036] The monofluorine absorption circulation tank 10 and the difluorine absorption circulation tank 16 are connected by a connecting pipe 13. The two ends of the connecting pipe 13 are located in the upper region of the monofluorine absorption circulation tank 10 and the difluorine absorption circulation tank 16, and the end closer to the difluorine absorption circulation tank 16 is higher than the end closer to the monofluorine absorption circulation tank 10.

[0037] One end of the overflow pipe 7 is connected to the upper part of the fluorine absorption circulation tank 10, and the other end is connected to the fluorosilicic acid intermediate tank 4, with the end closer to the fluorine absorption circulation tank 10 being higher than the end closer to the fluorosilicic acid intermediate tank 4.

[0038] By installing level gauges 11 on both the monofluoride absorption circulation tank 10 and the difluoride absorption circulation tank 16, the liquid levels of the two tanks can be monitored simultaneously, facilitating precise control of liquid level balance. The height difference design at both ends of the connecting pipe 13 utilizes gravity to allow the liquid in the difluoride absorption circulation tank 16 to flow naturally to the monofluoride absorption circulation tank 10, achieving automatic replenishment; the height difference design of the overflow pipe 7 utilizes gravity to allow the qualified liquid in the monofluoride absorption circulation tank 10 to automatically flow into the fluorosilicic acid intermediate tank 4. The dual level gauges 11 monitoring improve the comprehensiveness and accuracy of liquid level monitoring, ensuring stable liquid levels in both tanks. The height difference design of the connecting pipe 13 and the overflow pipe 7 enables automatic liquid flow, reducing the use of power equipment, lowering energy consumption, and laying the foundation for subsequent continuous production.

[0039] In this embodiment, as Figure 1 As shown, the absorbent in the monofluoride absorption circulation tank 10 and the difluoride absorption circulation tank 16 is fluorosilicic acid, and the fluorosilicic acid product is produced by the monofluoride absorption circulation tank 10.

[0040] It is clearly defined that the absorbent in the monofluoride absorption circulation tank 10 and the difluoride absorption circulation tank 16 is fluorosilicic acid, and that the fluorosilicic acid product is only produced by the monofluoride absorption circulation tank 10, thus determining the source of the product and the properties of the absorbent. The product output location is clearly defined as the monofluoride absorption circulation tank 10, facilitating quality control and traceability during production and ensuring the targeted production and collection of fluorosilicic acid products.

[0041] Specifically, such as Figure 1 , Figure 2 As shown, a fluorine absorption circulation tank 10 has an overflow port 9 and a connection port 12 on both sides, respectively. A fluorosilicic acid intermediate tank 4 has an overflow port 6 on one side, and a difluorine absorption circulation tank 16 has a connection port 14 on one side. The two ends of the connecting pipe 13 are connected to the overflow port 9 and the connection port 12 of the fluorine absorption circulation tank, respectively. The two ends of the overflow pipe 7 are connected to the overflow port 9 and the overflow port 6 of the fluorosilicic acid intermediate tank, respectively.

[0042] By setting specific interfaces such as the overflow port 9 of the monofluorine absorption circulation tank, the connection port 12 of the monofluorine absorption circulation tank, the overflow port 6 of the fluorosilicic acid intermediate tank, and the connection port 14 of the difluorine absorption circulation tank, and by connecting the connecting pipe 13 and the overflow pipe 7 to the corresponding interfaces, the connection method of each component is standardized, ensuring that the liquid flows between the tanks along a predetermined path. This makes the connection of the monofluorine absorption circulation tank 10, the difluorine absorption circulation tank 16, and the fluorosilicic acid intermediate tank 4 in the system more reasonable and orderly through the connecting pipe 13, the overflow pipe 7, and the interfaces, reducing leakage and chaos during liquid flow, improving the stability and reliability of system operation, and facilitating installation and maintenance.

[0043] Furthermore, such as Figure 1 As shown, the top height of the fluorosilicic acid intermediate tank 4 is higher than the top height of the fluorine absorption circulation tank 10, and the bottom of the fluorosilicic acid intermediate tank 4 is connected to an axial flow pump 5. The fluorine absorption circulation tank 10 introduces qualified fluorosilicic acid into the fluorosilicic acid intermediate tank 4 through the overflow pipe 7. The axial flow pump 5 is used to transport the fluorosilicic acid in the fluorosilicic acid intermediate tank 4 to the finished product tank.

[0044] The top of the fluorosilicic acid intermediate tank 4 is higher than that of the monofluorinated absorption and circulation tank 10, using the height difference to prevent backflow of liquid in the intermediate tank. The axial flow pump 5 provides power for transporting fluorosilicic acid from the intermediate tank 4 to the finished product tank. The monofluorinated absorption and circulation tank 10 introduces qualified fluorosilicic acid into the fluorosilicic acid intermediate tank 4 through the overflow pipe 7. This avoids the backflow of liquid from the fluorosilicic acid intermediate tank 4 into the monofluorinated absorption and circulation tank 10, which would affect production. The axial flow pump 5 enables efficient transport of fluorosilicic acid from the intermediate tank 4 to the finished product tank, ensuring the continuity of product collection.

[0045] Furthermore, such as Figure 1 As shown, the difluoride absorption circulation tank 16 is externally connected to a water supply device 19. A flow meter 18 is installed on the water supply pipe of the water supply device 19, and the flow rate of the water supply device 19 is controlled at 3-10 m³ / h by the flow meter 18. 3 / h.

[0046] The water replenishment device 19 replenishes the liquid in the difluoride absorption circulation tank 16, and the flow meter 18 can precisely control the water replenishment volume, so that the water replenishment volume matches the system consumption, and the water replenishment volume is controlled between 3-10m³. 3 / h. Precise water replenishment control ensures a stable liquid volume in the difluoride absorption circulation tank 16, providing a reliable guarantee for the liquid replenishment of the monofluoride absorption circulation tank 10, maintaining the liquid balance within the system, and ensuring the continuous and efficient progress of the absorption reaction.

[0047] Furthermore, such as Figure 1 , Figure 2As shown, the installation position of the connecting pipe 13 on the monofluorine absorption circulation tank 10 and the difluorine absorption circulation tank 16 is located in the range of 5 / 10 to 9 / 10 of the tank height. The vertical height difference between the monofluorine absorption circulation tank connection port 12 and the difluorine absorption circulation tank connection port 14 is 5cm-30cm, and the vertical height difference between the monofluorine absorption circulation tank overflow port 9 and the difluorine absorption circulation tank connection port 14 is 10cm-50cm.

[0048] The installation position of the connecting pipe 13 on the monofluorine absorption circulation tank 10 and the difluorine absorption circulation tank 16 is located in the range of 5 / 10 to 9 / 10 of the tank height. The vertical height difference between the monofluorine absorption circulation tank connection port 12 and the difluorine absorption circulation tank connection port 14 is 5cm-30cm, and the vertical height difference between the monofluorine absorption circulation tank overflow port 9 and the difluorine absorption circulation tank connection port 14 is 10cm-50cm. This further optimizes the natural flow conditions of the liquid and ensures smooth liquid replenishment and overflow. This makes the flow of liquid between the monofluorine absorption circulation tank 10 and the difluorine absorption circulation tank 16 through the connecting pipe 13, and the flow from the monofluorine absorption circulation tank 10 to the fluorosilicic acid intermediate tank 4 through the overflow pipe 7, more stable and efficient, reducing flow resistance, avoiding liquid stagnation or poor flow, and ensuring the continuous and stable operation of the system.

[0049] Furthermore, such as Figure 1 As shown, the overflow pipe 7 is equipped with a regulating valve 8, which is selected from gate valve, globe valve, check valve, butterfly valve, ball valve, plug valve, control valve or diaphragm valve. The inner diameter of the overflow pipe 7 is φ10cm-φ30cm, and the material is selected from polyethylene, polyvinyl chloride, polypropylene, ABS plastic, polytetrafluoroethylene or polyphenylene sulfide. The fluorosilicic acid intermediate tank 4 has a built-in stirrer 3, and the working speed of the stirrer 3 is 30-100r / min. The fluorosilicic acid intermediate tank 4 is made of PP material, with an inner diameter of φ3000mm and a height of 2500mm.

[0050] The regulating valve 8 on the overflow pipe 7 controls the flow rate and velocity of the liquid inside the pipe. Various types of regulating valves are available. The inner diameter of the overflow pipe 7 is φ10cm-φ30cm, and the material is selected from various corrosion-resistant materials to ensure smooth liquid flow and durability. The agitator 3 built into the fluorosilicic acid intermediate tank 4 agitates the liquid inside the tank to prevent sedimentation, with a rotation speed of 30-100 r / min. The fluorosilicic acid intermediate tank 4 is made of PP material, with an inner diameter of φ3000mm and a height of 2500mm, adapting to its working environment and capacity requirements. The regulating valve 8 enables precise control of the overflow process within the overflow pipe 7. Suitable overflow pipe 7 parameters extend its service life and reduce maintenance costs. The agitator 3 ensures the uniformity of the liquid within the fluorosilicic acid intermediate tank 4. The material and dimensions of the fluorosilicic acid intermediate tank 4 enable it to reliably and stably perform its buffering and temporary storage functions.

[0051] Furthermore, such as Figure 1 , Figure 3 As shown, both the monofluoride absorption tower 1 and the difluoride absorption circulation tank 16 are equipped with spray devices 2. The monofluoride absorption tower 1 is connected to the monofluoride absorption circulation tank 10 through a circulation pipeline, and a liquid pump and valve 17 are installed on the pipeline. The top of the monofluoride absorption tower 1 is connected to the difluoride absorption tower 15 through a pipeline. The difluoride absorption tower 15 is connected to the difluoride absorption circulation tank 16 through a circulation pipeline, and a liquid pump and valve 17 are installed on the pipeline. A vacuum pipe is connected to the top of the difluoride absorption tower 15.

[0052] Both the monofluorinated absorption tower 1 and the difluorinated absorption circulation tank 16 are equipped with spray devices 2, which can evenly spray the liquid in the circulation tank to enhance the contact with the waste gas. The monofluorinated absorption tower 1 is connected to the monofluorinated absorption circulation tank 10 through a circulation pipeline, which is equipped with a liquid pump and valve 17. The difluorinated absorption tower 15 is connected to the difluorinated absorption circulation tank 16 through a circulation pipeline, which is equipped with a liquid pump and valve 17, so that the liquid circulates between the tower body and the circulation tank, improving the absorption efficiency. The top of the difluorinated absorption tower 15 is connected to a vacuum pipe to create a vacuum environment for the difluorinated absorption tower 15, which is beneficial for waste gas treatment. The spray device 2 increases the contact area between the liquid and the waste gas and the absorption effect; the circulation pipeline realizes the recycling of liquid between the monofluorinated absorption tower 1 and the monofluorinated absorption circulation tank 10, and between the difluorinated absorption tower 15 and the difluorinated absorption circulation tank 16, improving resource utilization; the vacuum pipe ensures the waste gas treatment effect of the difluorinated absorption tower 15, making the entire waste gas absorption process more efficient.

[0053] The wet-process phosphoric acid concentration absorption and circulation system of this invention, based on the principle of multi-stage absorption and liquid level balance, treats fluorine-containing waste gas in stages through a series of monofluorine absorption tower 1 and difluorine absorption tower 15. The system utilizes the liquid level difference of the circulation tank components and the pipeline design to achieve automatic liquid flow and continuous production. Specifically, the monofluorine absorption tower 1 first performs preliminary absorption of the fluorine-containing waste gas; the waste gas that is not completely absorbed enters the difluorine absorption tower 15 for further treatment. The monofluorine absorption circulation tank 10 and the difluorine absorption circulation tank 16 are automatically replenished by the height difference of the connecting pipe 13. The qualified fluorosilicic acid in the monofluorine absorption circulation tank 10 flows into the fluorosilicic acid intermediate tank 4 through the height difference of the overflow pipe 7, and is then transported to the finished product tank by the axial flow pump 5. Simultaneously, the water replenishment device 19 replenishes water to the difluorine absorption circulation tank 16 to maintain system balance.

[0054] When the system starts up, first check whether the connections of each device are normal and ensure that valve 17 is in the closed position. Then, inject an appropriate amount of liquid into the difluorine absorption circulation tank 16. The amount of water replenishment is controlled by the water replenishment device 19 and the flow meter 18, so that the liquid level in the difluorine absorption circulation tank 16 gradually reaches the appropriate level. Under the action of the liquid level difference, the liquid in the difluorine absorption circulation tank 16 flows into the primary fluorine absorption circulation tank 10 through the connecting pipe 13 until the liquid levels of the two tanks reach equilibrium. The level gauge 11 monitors and displays the liquid levels of the two tanks in real time.

[0055] After the fluorinated waste gas enters the monofluorinated absorption tower 1, the pump and valve 17 on the pipeline connecting the monofluorinated absorption tower 1 and the monofluorinated absorption circulation tank 10 are turned on. The fluorosilicic acid in the monofluorinated absorption circulation tank 10 is pumped to the spray device 2 inside the monofluorinated absorption tower 1. After being evenly sprayed by the spray device 2, it fully contacts the fluorinated waste gas and absorbs most of the fluorides. The absorbed liquid is returned to the monofluorinated absorption circulation tank 10. As the absorption process proceeds, the concentration of fluorosilicic acid in the monofluorinated absorption circulation tank 10 gradually increases.

[0056] A small amount of fluorine-containing waste gas that is not completely absorbed by the monofluorine absorption tower 1 enters the difluorine absorption tower 15 through a pipeline. The liquid pump and valve 17 on the pipeline connecting the difluorine absorption tower 15 and the difluorine absorption circulation tank 16 are turned on. The liquid in the difluorine absorption circulation tank 16 is pumped to the spray device 2 inside the difluorine absorption tower 15 for further absorption of the waste gas. The absorbed liquid then flows back to the difluorine absorption circulation tank 16. Simultaneously, the vacuum pipe at the top of the difluorine absorption tower 15 operates, creating a vacuum environment inside the tower and improving absorption efficiency.

[0057] Once the concentration of fluorosilicic acid in the fluorine absorption circulation tank 10 reaches the standard, the regulating valve 8 on the overflow pipe 7 is opened. Under the action of the height difference, the qualified fluorosilicic acid flows into the intermediate fluorosilicic acid tank 4 through the overflow pipe 7. The stirrer 3 in the intermediate fluorosilicic acid tank 4 is started (speed 30-100 r / min) to stir the fluorosilicic acid to maintain its uniformity. The axial flow pump 5 is turned on to transport the fluorosilicic acid in the intermediate fluorosilicic acid tank 4 to the finished product tank, realizing the continuous production of fluorosilicic acid.

[0058] Throughout the operation, the flow meter 18 continuously monitors the water supply from the water supply device 19 to ensure that the water supply remains stable at 3-10 m³ / h. 3 / h, maintaining the liquid level balance in the difluoride absorption circulation tank 16 and the monofluoride absorption circulation tank 10, ensuring continuous, stable and efficient operation of the system.

[0059] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A wet-process phosphoric acid concentration and absorption circulation system, comprising a tower body and a circulation tank assembly; characterized in that: The tower body includes a monofluoride absorption tower (1) and a difluoride absorption tower (15) arranged in series. The circulation tank assembly includes a monofluoride absorption circulation tank (10), a difluoride absorption circulation tank (16), a fluorosilicic acid intermediate tank (4), a connecting pipe (13), an overflow pipe (7), and a level gauge (11). The level gauge (11) is installed on the monofluoride absorption circulation tank (10) and the difluoride absorption circulation tank (16). The monofluorine absorption circulation tank (10) and the difluorine absorption circulation tank (16) are connected by a connecting pipe (13). The two ends of the connecting pipe (13) are located in the upper region of the monofluorine absorption circulation tank (10) and the difluorine absorption circulation tank (16), and the end closer to the difluorine absorption circulation tank (16) is higher than the end closer to the monofluorine absorption circulation tank (10). One end of the overflow pipe (7) is connected to the upper part of the fluorine absorption circulation tank (10), and the other end is connected to the fluorosilicic acid intermediate tank (4). The end closer to the fluorine absorption circulation tank (10) is higher than the end closer to the fluorosilicic acid intermediate tank (4).

2. The wet-process phosphoric acid concentration and absorption circulation system according to claim 1, characterized in that: The absorbent in the monofluorine absorption circulation tank (10) and the difluorine absorption circulation tank (16) is fluorosilicic acid, and the fluorosilicic acid product is produced by the monofluorine absorption circulation tank (10).

3. The wet-process phosphoric acid concentration and absorption circulation system according to claim 1, characterized in that: The fluorine absorption circulation tank (10) is provided with an overflow port (9) and a connection port (12) on both sides. The fluorosilicic acid intermediate tank (4) is provided with an overflow port (6) on one side. The difluorine absorption circulation tank (16) is provided with a connection port (14) on one side. The two ends of the connecting pipe (13) are connected to the overflow port (9) and the connection port (12) of the fluorine absorption circulation tank, respectively. The two ends of the overflow pipe (7) are connected to the overflow port (9) of the fluorine absorption circulation tank and the overflow port (6) of the fluorosilicic acid intermediate tank, respectively.

4. The wet-process phosphoric acid concentration and absorption circulation system according to claim 1, characterized in that: The top height of the fluorosilicic acid intermediate tank (4) is higher than the top height of the fluorine absorption circulation tank (10), and the bottom of the fluorosilicic acid intermediate tank (4) is connected to an axial flow pump (5). The fluorine absorption circulation tank (10) introduces qualified fluorosilicic acid into the fluorosilicic acid intermediate tank (4) through an overflow pipe (7). The axial flow pump (5) is used to transport the fluorosilicic acid in the fluorosilicic acid intermediate tank (4) to the finished product tank.

5. The wet-process phosphoric acid concentration and absorption circulation system according to claim 1, characterized in that: The difluorine absorption circulation tank (16) is externally connected with a water supplement device (19), a flow meter (18) is installed on the water delivery pipeline of the water supplement device (19), and the flow of the water supplement device (19) is controlled at 3-10 m 3 / h through the flow meter (18).

6. The wet-process phosphoric acid concentration and absorption circulation system according to claim 3, characterized in that: The installation position of the connecting pipe (13) on the monofluorine absorption circulation tank (10) and the difluorine absorption circulation tank (16) is located in the range of 5 / 10 to 9 / 10 of the tank height. The vertical height difference between the monofluorine absorption circulation tank connection port (12) and the difluorine absorption circulation tank connection port (14) is 5cm-30cm. The vertical height difference between the monofluorine absorption circulation tank overflow port (9) and the difluorine absorption circulation tank connection port (14) is 10cm-50cm.

7. The wet-process phosphoric acid concentration and absorption circulation system according to claim 1, characterized in that: The overflow pipe (7) is equipped with a regulating valve (8), which is selected from gate valve, stop valve, check valve, butterfly valve, ball valve, plug valve, control valve or diaphragm valve. The inner diameter of the overflow pipe (7) is φ10cm-φ30cm. The fluorosilicic acid intermediate tank (4) has a built-in stirrer (3), which operates at a speed of 30-100r / min. The fluorosilicic acid intermediate tank (4) is made of PP material.

8. The wet-process phosphoric acid concentration and absorption circulation system according to claim 1, characterized in that: Both the monofluorine absorption tower (1) and the difluorine absorption circulation tank (16) are equipped with spray devices (2). The monofluorine absorption tower (1) is connected to the monofluorine absorption circulation tank (10) through a circulation pipeline, and a liquid pump and valve (17) are installed on the pipeline. The top of the monofluorine absorption tower (1) is connected to the difluorine absorption tower (15) through a pipeline. The difluorine absorption tower (15) is connected to the difluorine absorption circulation tank (16) through a circulation pipeline, and a liquid pump and valve (17) are installed on the pipeline. A vacuum pipe is connected to the top of the difluorine absorption tower (15).

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