Phosphogypsum filtering and separating device for wet-process phosphoric acid production

Abstract

The utility model discloses a phosphogypsum filtering and separating device for wet-process phosphoric acid production, which comprises a disc filter, a processing mechanism, a vacuum tank, a feeding pipe and a refiltering mechanism, the vacuum tank is connected to the right side of a liquid outlet pipe below the disc filter, the feeding pipe is arranged above the processing mechanism, the refiltering mechanism is arranged on the front side of the disc filter, and the processing mechanism is arranged on the right side of the liquid outlet pipe. The processing mechanism and the refiltering mechanism are in telecommunication connection with a controller of the disc filter; the refiltering mechanism further comprises a stirring mechanism and a filter pressing mechanism, the stirring mechanism for stirring and mixing phosphogypsum and flushing fluid is arranged above the material receiving box, and the filter pressing mechanism for secondary separation and filtration is arranged on the front side of the disc filter. The device has the function of improving the extraction efficiency of secondary soaking; phosphogypsum generated after filtration is filtered for multiple times, so that the resource utilization rate is increased, and the applicability of the device is improved; the filtered phosphogypsum is flushed out of the material collecting box, and flushing water can be recycled, so that water resources are saved while residues of the phosphogypsum are cleaned.

Description

Technical Field

[0001] This utility model belongs to the technical field of filtration and separation devices, and particularly relates to a phosphogypsum filtration and separation device for wet-process phosphoric acid production. Background Technology

[0002] The wet process for producing phosphoric acid is a commonly used method. Its main steps include crushing, acid leaching, filtration, concentration, and crystallization of phosphate rock. This process is highly efficient and environmentally friendly, and is widely used in agricultural fertilizers, food additives, pharmaceuticals, and chemicals. In the filtration stage, the slurry after acid leaching of phosphoric acid is separated into phosphate solution and phosphogypsum solids through filtration, typically using a pressure filter or vacuum filter.

[0003] A prior art example is the vacuum filter disclosed in Chinese Patent (CN217490017U). The vacuum filter includes a flat plate, a rotating shaft, a filter cloth, a discharge device, and a first washing device. The flat plate includes through holes, and the rotating shaft is connected to the flat plate. The filter cloth covers the through holes and is used to filter materials. The discharge device is used to remove material from the filter cloth. The first washing device is arranged adjacent to the discharge device along the rotation direction of the flat plate, and is used to separate at least a portion of the residual material from the filter cloth.

[0004] This method has the following drawbacks: First, during the filtration and separation of the slurry after acid leaching, the resulting phosphogypsum product usually contains some recyclable residues such as soluble phosphorus and soluble fluorine. Multiple soaking and filtration processes are required to extract these residues and improve resource utilization. However, a single vacuum filter needs to be linked with other equipment to achieve the secondary extraction and separation function, reducing the applicability of the device. Second, the phosphogypsum blocks produced after vacuum filtration are in block form. These blocky gypsum blocks have a small contact area with the reagent during secondary soaking, resulting in low extraction efficiency. Third, the extracted phosphogypsum blocks are directly recycled into the recycling bin, where they collide and generate debris. This debris is difficult to clean thoroughly during subsequent handling and transportation. Using water for cleaning also consumes a large amount of water resources, which often need to be filtered again to remove impurities before being recycled, increasing the number of production steps.

[0005] Therefore, this paper provides a phosphogypsum filtration and separation device for wet-process phosphoric acid production. Utility Model Content

[0006] To address the aforementioned technical problems, this utility model discloses a phosphogypsum filtration and separation device for wet-process phosphoric acid production, which improves the extraction efficiency of secondary soaking; the phosphogypsum produced after filtration is filtered multiple times to improve resource utilization and enhance the applicability of the device; the filtered phosphogypsum is washed out of the collection box by rinsing water, and the rinsing water can be recycled and reused, thus cleaning up phosphogypsum residue while saving water resources.

[0007] To achieve the above-mentioned technical effects, this utility model provides a phosphogypsum filtration and separation device for wet-process phosphoric acid production, including a disc filter, a processing mechanism, a vacuum tank, a feed pipe, and a re-filtration mechanism. The vacuum tank is connected to the right side of the lower outlet pipe of the disc filter, the feed pipe is located above the processing mechanism, and the re-filtration mechanism is located in front of the disc filter. The processing mechanism, the re-filtration mechanism, and the controller of the disc filter are electrically connected. The re-filtration mechanism also includes a stirring mechanism and a filter press mechanism. The stirring mechanism for mixing phosphogypsum and rinsing liquid is located above the receiving box, and the filter press mechanism for secondary separation and filtration of phosphogypsum is located in front of the disc filter.

[0008] Preferably, the processing mechanism further includes a cloth-laying mechanism, a rinsing mechanism, a water washing mechanism, a screw unloading mechanism, and a receiving box. The cloth-laying mechanism is located above and in front of the disc filter, the rinsing mechanism is located to the right of the cloth-laying mechanism, the water washing mechanism is located to the right and rear of the rinsing mechanism, the screw unloading mechanism is located to the left of the disc filter, and the receiving box is located between the screw unloading mechanism and the disc filter.

[0009] Preferably, the stirring mechanism further includes bevel gear a, bevel gear b, transmission rod, gear a, gear b, and stirring rod. Bevel gear a is located at the front end of the output rod of the drive motor of the screw unloading mechanism. Bevel gear b is meshed below bevel gear a. The transmission rod is located below bevel gear b. Gear a is located below the transmission rod a. Gear b is meshed to the right of gear a. The stirring rod is located above gear b.

[0010] Preferably, the filter press mechanism further includes a flushing water pipeline, a filter press pipeline, a filter press device, a circulation pipeline, an electric three-way valve, and a return water pipeline. The flushing water pipeline is located above and behind the receiving box. The filter press pipeline is located in front of the receiving box and connects to the inlet pipe above the filter press device located in front of the receiving box. The electric three-way valve is located on the filter press pipeline. The circulation pipeline is located above the electric three-way valve and its end is connected to the top of the fabric distribution mechanism. The return water pipeline is located below the filter press device and its end is connected to the top of the receiving box.

[0011] Preferably, a water pump a is provided on the front side of the electric three-way valve, and a flexible connection a is provided on the front side of the electric three-way valve.

[0012] Preferably, a water pump b is installed on the return water pipeline, and a flexible connection b is installed on the rear side of the water pump b.

[0013] Preferably, the filter press further includes a vibrating base, hydraulic push rod a, hydraulic push rod b, filter plate, pressure plate, filter cylinder, cake outlet, and recovery box. The filter cylinder is inclined above the vibrating base, hydraulic push rod a is located at the bottom of the filter cylinder with its front end passing through the bottom of the filter cylinder, filter plate is located at the front end of hydraulic push rod a, hydraulic push rod b is located at the top of the filter cylinder with its front end passing through the top of the filter cylinder, pressure plate is located at the top of hydraulic push rod b, cake outlet is located below the upper part of the filter cylinder, and recovery box is located below the cake outlet.

[0014] Preferably, the vibration base further includes a mounting plate, an elastic pad, and a vibration motor. The mounting plate is positioned below the hydraulic push rod a, the elastic pad is positioned between the mounting plates, and the vibration motor is positioned above the mounting plate.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] The device is equipped with a stirring mechanism that can be linked with a screw unloading mechanism to thoroughly mix the filtered phosphogypsum blocks with the soaking solution, thereby improving the extraction efficiency of secondary soaking. It also features a stirring mechanism and a filter press mechanism, which can filter the phosphogypsum produced after the disc filter multiple times, improving resource utilization and the applicability of the device. The filter press device uses flushing water to wash the filtered phosphogypsum out of the collection box, and the flushing water can be recycled and reused, thus cleaning up phosphogypsum residue while saving water resources. Attached Figure Description

[0017] Figure 1 This is a front view of the present invention;

[0018] Figure 2 This is a top view of the present invention;

[0019] Figure 3 This is a left view of the present invention;

[0020] Figure 4 yes Figure 3 A sectional view of section a.

[0021] Figure 5 yes Figure 3 A sectional view of section b in the middle;

[0022] The attached diagram lists the components represented by each number as follows:

[0023] 1. Disc filter; 2. Fabric feeding mechanism; 3. Washing mechanism; 4. Water washing mechanism; 5. Screw unloading mechanism; 6. Collection box; 7. Vacuum tank; 8. Feed pipe; 9. Stirring mechanism; 10. Filter press mechanism; 11. Bevel gear a; 12. Bevel gear b; 13. Transmission rod; 14. Gear a; 15. Gear b; 16. Stirring rod; 17. Washing water pipeline; 18. Filter press pipeline; 19. Filter press device; 20. Circulation pipeline; 21. Electric three-way valve; 22. Return water pipeline; 23. Water pump a; 24. Flexible connection a; 25. Water pump b; 26. Flexible connection b; 27. Vibrating base; 28. Hydraulic push rod a; 29. ​​Hydraulic push rod b; 30. Filter plate; 31. Pressure plate; 32. Filter cylinder; 33. Cake outlet; 34. Recovery box; 35. Mounting plate; 36. Elastic pad; 37. Vibrating motor. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0025] The prior art in this embodiment has the following problems: The inventors have found the following defects in the prior art: First, when filtering and separating the slurry after acid leaching, the resulting phosphogypsum product usually contains some recyclable residues such as soluble phosphorus and soluble fluorine. It is necessary to soak and filter the phosphogypsum multiple times to extract these residues to improve resource utilization. However, a single vacuum filter needs to be linked with other equipment to achieve the function of secondary extraction and separation, which reduces the applicability of the device; Second, the phosphogypsum blocks produced after vacuum filtration are in block shape. These blocky gypsum blocks have a small contact area with the reagent during secondary soaking, resulting in low soaking extraction efficiency; Third, the extracted phosphogypsum blocks are directly recycled into the recycling box. Collision in the recycling box generates debris. These debris are not easy to clean up during subsequent cleaning and transportation. Using water cleaning will also consume a lot of water resources. These water resources also need to be filtered again to remove impurities before they can be recycled, which increases the production process; Example 1

[0026] like Figures 1 to 5 As shown:

[0027] Therefore, the inventor provides a phosphogypsum filtration and separation device for wet-process phosphoric acid production, including a disc filter 1, a processing mechanism, a vacuum tank 7, a feed pipe 8, and a re-filtration mechanism. The vacuum tank 7 is connected to the right side of the lower outlet pipe of the disc filter 1. The feed pipe 8 is located above the processing mechanism. The re-filtration mechanism is located in front of the disc filter 1. The processing mechanism, the re-filtration mechanism, and the controller (not shown in the figure) of the disc filter 1 are electrically connected. The re-filtration mechanism also includes a stirring mechanism 9 and a filter press mechanism 10. The stirring mechanism 9, which mixes the phosphogypsum and the rinsing liquid, is located above the receiving box 6. The filter press mechanism 10, which performs secondary separation and filtration of the phosphogypsum, is located in front of the disc filter 1.

[0028] Furthermore, the processing mechanism also includes a cloth-laying mechanism 2, a rinsing mechanism 3, a water washing mechanism 4, a screw unloading mechanism 5, and a receiving box 6. The cloth-laying mechanism 2 is located above and in front of the disc filter 1, the rinsing mechanism 3 is located to the right of the cloth-laying mechanism 2, the water washing mechanism 4 is located to the right and rear of the rinsing mechanism 3 respectively, the screw unloading mechanism 5 is located to the left of the disc filter 1, and the receiving box 6 is located between the screw unloading mechanism 5 and the disc filter 1.

[0029] The acid-leached slurry enters the cloth-spreading mechanism 2 through the feed pipe 8 and is evenly distributed onto the filter disc of the disc filter 1. As the disc rotates, the slurry is rinsed by the rinsing mechanism 3, which dispenses rinsing agent. Then, it is rinsed by the water washing mechanism 4, which sprays out cleaning water. The pipe at the top of the vacuum tank is connected to the vacuum generator (not shown in the figure). The phosphate solution filtered from the disc filter 1 is drawn into the vacuum tank 7 from below through the vacuum tank 7 under negative pressure. The remaining phosphogypsum is rolled into the receiving box 6 by the spiral unloading mechanism 5 through the spiral blades. After being stirred by the stirring mechanism 9 in the receiving box 6, the phosphogypsum can be recirculated through the pipeline to the cloth-spreading mechanism 2 for soaking, rinsing, and water washing to separate and extract the remaining phosphate substances. The extracted phosphogypsum is recycled back to the receiving box 6. After rinsing, the phosphogypsum is pressed into phosphogypsum cake by the filter press mechanism 10 and discharged. The rinsing water can be recycled. Example 2

[0030] like Figures 1 to 5 As shown:

[0031] Furthermore, the stirring mechanism 9 also includes a bevel gear a11, a bevel gear b12, a transmission rod 13, a gear a14, a gear b15, and a stirring rod 16. The bevel gear a11 is located at the front end of the output rod of the drive motor of the screw unloading mechanism 5. The bevel gear b12 is meshed below the bevel gear a11. The transmission rod 13 is located below the bevel gear b12. The gear a14 is located below the transmission rod 13a. The gear b15 is meshed to the right of the gear a14. The stirring rod 16 is located above the gear b15.

[0032] During the unloading process of the spiral unloading mechanism 5, the drive motor drives the spiral blades to rotate through the output end, rolling up the phosphogypsum above the disc filter 1 and dropping it into the receiving box 6. During this process, the bevel gear a11 rotates with the spiral blades, and through the bevel gear b12, drives the gear a14 below the transmission rod 13 to rotate, which in turn drives the stirring rod 16 above the gear b15 to rotate, stirring the material falling into the receiving box 6, breaking up the material, increasing the mixing efficiency of the phosphogypsum and the soaking solution, increasing the soaking efficiency, and soaking out the remaining phosphate substances in the phosphogypsum. Furthermore, the phosphogypsum in the receiving box 6 can be easily rinsed and drained through soaking and rinsing. In this way, the spiral unloading mechanism 5 can be linked to thoroughly mix the filtered phosphogypsum blocks with the soaking solution, improving the extraction efficiency of the secondary soaking. Example 3

[0033] like Figures 1 to 5 As shown:

[0034] Furthermore, the filter press mechanism 10 also includes a flushing water pipe 17, a filter press pipe 18, a filter press device 19, a circulation pipe 20, an electric three-way valve 21, and a return water pipe 22. The flushing water pipe 17 is located above the rear side of the receiving box 6. The filter press pipe 18 is located in front of the receiving box 6 and is connected to the inlet pipe above the filter press device 19 located in front of the receiving box 6. The electric three-way valve 21 is located on the filter press pipe 18. The circulation pipe 20 is located above the electric three-way valve 21 and its end is connected to the top of the material distribution mechanism 2. The return water pipe 22 is located below the filter press device 19 and its end is connected to the top of the receiving box 6.

[0035] Furthermore, a water pump a23 is provided on the front side of the electric three-way valve 21, and a flexible connection a24 is provided on the front side of the electric three-way valve 21.

[0036] Furthermore, a water pump b25 is installed on the return water pipe 22, and a flexible connection b26 is installed on the rear side of the water pump b25;

[0037] In this process, after the phosphogypsum is initially filtered, it is rolled into the receiving box 6 by the screw unloading mechanism 5. The controller then introduces soaking agent through the flushing water pipe 17 to break up the phosphogypsum that has clumped due to the negative pressure filtration. Under the stirring of the stirring mechanism 9, the phosphogypsum is mixed with the soaking agent and then pumped out by the water pump through the electric three-way valve 21. The electric three-way valve 21 opens the passage between the filter press pipe 18 and the circulation pipe 20, and the mixture is pumped back to the cloth feeding mechanism 2 and then back into the disc filter 1 to extract and filter out the phosphates. After the second flush, the phosphogypsum is rolled back into the receiving box 6 by the screw unloading mechanism 5, and the clean water is discharged through the flushing water pipe 17. After the mixing mechanism 9 washes all the materials in the receiving box 6, the electric three-way valve 21 switches to close the circulation pipeline 20. The water pump a23 draws the mixture into the filter press 19, presses the phosphogypsum into a mud cake and discharges it. The filtered clean water is pumped by the water pump b25 through the return water pipeline 22 to the top of the receiving box 6 to wash the receiving box 6 again. Alternatively, the electric three-way valve 21 can be controlled to discharge the reused clean water through the circulation pipeline 20 into the cloth spreading mechanism 2 to wash the disc filter 1. In this way, the phosphogypsum produced after the disc filter 1 is filtered multiple times, improving resource utilization and the applicability of the device. Example 4

[0038] like Figures 1 to 5 As shown:

[0039] Furthermore, the filter press device 19 also includes a vibrating base 27, a hydraulic push rod a28, a hydraulic push rod b29, a filter plate 30, a pressure plate 31, a filter cylinder 32, a cake outlet 33, and a recovery box 34. The filter cylinder 32 is inclinedly arranged above the vibrating base 27. The hydraulic push rod a28 is arranged at the bottom of the filter cylinder 32, and the front end of the hydraulic push rod a28 passes through the bottom of the filter cylinder 32. The filter plate 30 is arranged at the front end of the hydraulic push rod a28. The hydraulic push rod b29 is arranged at the top of the filter cylinder 32, and the front end of the hydraulic push rod b29 passes through the top of the filter cylinder 32. The pressure plate 31 is arranged at the top of the hydraulic push rod b29. The cake outlet 33 is arranged below the upper part of the filter cylinder 32, and the recovery box 34 is arranged below the cake outlet 33.

[0040] Furthermore, the vibration base 27 also includes a mounting plate 35, an elastic pad 36, and a vibration motor 37. The mounting plate 35 is located below the hydraulic push rod a28, the elastic pad 36 is located between the mounting plates 35, and the vibration motor 37 is located above the mounting plate 35.

[0041] The mixture carried out by the rinsing water flows into the filter cylinder 32 from the top, existing between the filter plate 30 and the pressure plate 31. At this time, hydraulic push rod a28 retracts and hydraulic push rod b29 extends. Then, hydraulic push rod a28 extends and hydraulic push rod b29 retracts, pushing the mixture between the filter plate 30 and the pressure plate 31 upwards within the filter cylinder 32. During this process, the gap between the filter plate 30 and the pressure plate 31 narrows, allowing the rinsing water to filter downwards through the filter plate 30. The filtered rinsing water collects downwards at the bottom of the filter cylinder 32. The phosphogypsum between the filter plate 30 and the pressure plate 31 is pressed into a sludge cake. Then, hydraulic push rods a28 and b29 retract, closing the gap between the filter plate 30 and the pressure plate 31. The mud cake between plates 31 is released, the vibration motor 37 is started, driving the device above the mounting plate 35 to vibrate, causing the elastic pad 36 between the mounting plates 35 to deform and vibrate. The elastic pad 36 can be a hollow rubber cylinder structure, shaking the mud cake into the recycling box 34 to complete the recycling. The flexible connection a24 and flexible connection b26 provide buffering between the filter cylinder 32 and the connected pipe when it vibrates. The rinsing water remaining at the bottom of the filter cylinder 32 can be pumped by the water pump b25 through the return water pipe 22 to the collection box 6 for reuse as rinsing water. In this way, the filtered phosphogypsum can be rinsed out of the collection box 6 by the rinsing water, and then pressed into mud cake for recycling. The rinsing water can also be recycled and reused, cleaning up the phosphogypsum residue while saving water resources.

[0042] In summary, the device is equipped with a stirring mechanism 9 that can be linked with the screw unloading mechanism 5 to thoroughly mix the filtered phosphogypsum blocks with the soaking solution, thereby improving the extraction efficiency of the secondary soaking. The stirring mechanism 9 and the filter press mechanism 10 can filter the phosphogypsum produced after the disc filter 1 multiple times, improving resource utilization and the applicability of the device. The filter press device 19 uses rinsing water to wash the filtered phosphogypsum out of the collection box 6, and the rinsing water can be recycled and reused, cleaning up phosphogypsum residue while saving water resources.

[0043] The working principle of this utility model:

[0044] After acid leaching, the slurry enters the feeding mechanism 2 through the feed pipe 8 and is evenly distributed onto the filter disc of the disc filter 1. As the disc rotates, the slurry is rinsed by the rinsing mechanism 3, which dispenses rinsing agent. Then, it is rinsed with cleaning water by the washing mechanism 4. Finally, it passes through the vacuum tank 7 from below, where the filtered phosphate solution is drawn into the vacuum tank 7 under negative pressure. During the unloading process of the screw unloading mechanism 5, the drive motor drives the screw blades through its output end to roll up the phosphogypsum above the disc filter 1, which then falls into the collection box 6. During this process, the bevel gear a1... 1. As the spiral blades rotate, the bevel gear b12 drives the gear a14 below the transmission rod 13 to rotate, which in turn drives the stirring rod 16 above the gear b15 to rotate, stirring the material falling into the receiving box 6, breaking up the material, increasing the mixing efficiency of phosphogypsum and soaking solution, increasing soaking efficiency, and soaking out the remaining phosphate substances in the phosphogypsum. Furthermore, the phosphogypsum in the receiving box 6 can be easily rinsed and drained through soaking and rinsing. This can be linked with the spiral unloading mechanism 5 to fully mix the filtered phosphogypsum blocks with the soaking solution, thereby improving the extraction efficiency of the secondary soaking.

[0045] After the phosphogypsum after preliminary filtration is rolled into the receiving box 6 by the screw unloading mechanism 5, the controller introduces soaking agent through the flushing water pipe 17 to disperse the phosphogypsum that has clumped due to negative pressure filtration. Under the stirring of the stirring mechanism 9, it is mixed with the soaking agent and then pumped out by the water pump through the electric three-way valve 21. The electric three-way valve 21 opens the passage between the filter press pipe 18 and the circulation pipe 20, and pumps the mixture back into the cloth feeding mechanism 2, and then back into the disc filter 1 to extract and filter out the phosphate. After the second rinsing, the phosphogypsum is rolled into the receiving box 6 again by the screw unloading mechanism 5. Clean water is discharged through the flushing water pipe 17. After the stirring mechanism 9 rinses all the material in the receiving box 6, the electric three-way valve 21 switches to close the passage of the circulation pipe 20, and the water pump a23 pumps the mixture into the filter press 19.

[0046] The mixture carried out by the rinsing water flows into the filter cylinder 32 from the top. The mixture exists between the filter plate 30 and the pressure plate 31. At this time, hydraulic push rod a28 retracts and hydraulic push rod b29 extends. Then, hydraulic push rod a28 extends and hydraulic push rod b29 retracts, pushing the mixture between the filter plate 30 and the pressure plate 31 upwards within the filter cylinder 32. During this process, the gap between the filter plate 30 and the pressure plate 31 narrows, allowing the rinsing water to filter downwards through the filter plate 30. The filtered rinsing water collects downwards at the bottom of the filter cylinder 32. After the phosphogypsum between the filter plate 30 and the pressure plate 31 is pressed into a sludge cake, hydraulic push rods a28 and b29 retract, closing the gap between the filter plate 30 and the pressure plate 31. When the mud cake is released, the vibration motor 37 starts, driving the device above the mounting plate 35 to vibrate, causing the elastic pad 36 between the mounting plates 35 to deform and vibrate. The elastic pad 36 can be a hollow rubber cylinder structure, shaking the mud cake into the recycling box 34 for recycling. The flexible connection a24 and flexible connection b26 provide buffering between the filter cylinder 32 and the connected pipe when it vibrates. The rinsing water remaining at the bottom of the filter cylinder 32 can be pumped by the water pump b25 through the return water pipe 22 into the collection box 6 for reuse as rinsing water. In this way, the filtered phosphogypsum can be rinsed out of the collection box 6 by the rinsing water, and then pressed into mud cake for recycling. The rinsing water can also be recycled and reused, cleaning up the phosphogypsum residue while saving water resources.

[0047] This allows for multiple filtrations of the phosphogypsum produced after filtration by disc filter 1, improving resource utilization and equipment efficiency.

[0048] This concludes the description of the working principle of the device.

[0049] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0050] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A phosphogypsum filtration and separation device for wet-process phosphoric acid production, comprising a disc filter, a processing mechanism, a vacuum tank, a feed pipe, and a re-filtration mechanism, wherein the vacuum tank is connected to the right side of the lower outlet pipe of the disc filter, the feed pipe is positioned above the processing mechanism, and the re-filtration mechanism is positioned in front of the disc filter; the processing mechanism and the re-filtration mechanism are electrically connected to the controller of the disc filter, characterized in that: The re-filtration mechanism also includes a stirring mechanism and a filter press mechanism. The stirring mechanism for mixing phosphogypsum and rinsing liquid is located above the receiving box, and the filter press mechanism for secondary separation and filtration of phosphogypsum is located on the front side of the disc filter.

2. The phosphogypsum filtration and separation device for wet-process phosphoric acid production according to claim 1, characterized in that: The processing mechanism also includes a cloth-laying mechanism, a rinsing mechanism, a water washing mechanism, a screw unloading mechanism, and a receiving box. The cloth-laying mechanism is located above and in front of the disc filter, the rinsing mechanism is located to the right of the cloth-laying mechanism, the water washing mechanism is located to the right and rear of the rinsing mechanism, the screw unloading mechanism is located to the left of the disc filter, and the receiving box is located between the screw unloading mechanism and the disc filter.

3. The phosphogypsum filtration and separation device for wet-process phosphoric acid production according to claim 1, characterized in that: The stirring mechanism further includes bevel gear a, bevel gear b, transmission rod, gear a, gear b, and stirring rod. Bevel gear a is located at the front end of the output rod of the drive motor of the screw unloading mechanism. Bevel gear b is meshed below bevel gear a. The transmission rod is located below bevel gear b. Gear a is located below the transmission rod a. Gear b is meshed to the right of gear a. The stirring rod is located above gear b.

4. The phosphogypsum filtration and separation device for wet-process phosphoric acid production according to claim 1, characterized in that: The filter press mechanism also includes a flushing water pipeline, a filter press pipeline, a filter press device, a circulation pipeline, an electric three-way valve, and a return water pipeline. The flushing water pipeline is located above and behind the receiving box. The filter press pipeline is located in front of the receiving box and connects to the inlet pipe above the filter press device located in front of the receiving box. The electric three-way valve is located on the filter press pipeline. The circulation pipeline is located above the electric three-way valve and its end is connected to the top of the material distribution mechanism. The return water pipeline is located below the filter press device and its end is connected to the top of the receiving box.

5. The phosphogypsum filtration and separation device for wet-process phosphoric acid production according to claim 4, characterized in that: A water pump a is provided on the front side of the electric three-way valve, and a flexible connection a is provided on the front side of the electric three-way valve.

6. The phosphogypsum filtration and separation device for wet-process phosphoric acid production according to claim 4, characterized in that: A water pump b is installed on the return water pipeline, and a flexible connection b is installed on the rear side of the water pump b.

7. The phosphogypsum filtration and separation device for wet-process phosphoric acid production according to claim 4, characterized in that: The filter press device further includes a vibrating base, hydraulic push rod a, hydraulic push rod b, filter plate, pressure plate, filter cylinder, cake outlet, and recovery box. The filter cylinder is inclinedly arranged above the vibrating base. Hydraulic push rod a is arranged at the bottom of the filter cylinder, with its front end passing through the bottom of the filter cylinder. The filter plate is arranged at the front end of hydraulic push rod a. Hydraulic push rod b is arranged at the top of the filter cylinder, with its front end passing through the top of the filter cylinder. The pressure plate is arranged at the top of hydraulic push rod b. The cake outlet is arranged below the upper part of the filter cylinder, and the recovery box is arranged below the cake outlet.

8. The phosphogypsum filtration and separation device for wet-process phosphoric acid production according to claim 7, characterized in that: The vibration base also includes a mounting plate, an elastic pad, and a vibration motor. The mounting plate is located below the hydraulic push rod a, the elastic pad is located between the mounting plates, and the vibration motor is located above the mounting plate.

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