Complete cloth and washing equipment for wet-process phosphoric acid process

Abstract

The invention relates to cloth and washing complete equipment for a wet-process phosphoric acid process, and belongs to the technical field of wet-process phosphoric acid process.The cloth and washing complete equipment for the wet-process phosphoric acid process comprises a cloth device and a washing water distribution device, and the washing water distribution device comprises a first-stage washing mechanism, a second-stage washing mechanism and a third-stage washing mechanism; each of the first-stage washing mechanism and the material distribution device comprises a distribution groove, a material distribution box and a feeding pipe, the distribution groove is provided with a material distribution hole for corresponding materials to flow out, an opening is formed in the bottom wall of the material distribution box, the opening is aligned to the middle of the corresponding distribution groove, the bottom wall of the material distribution box is in an inclined state, and the feeding pipe is connected with the material distribution box. The distance from the bottom wall of the material distribution box to the bottom wall of the distribution groove is gradually increased in the direction away from the material distribution holes, and the feeding pipe communicates with the material distribution box and is located on the side, away from the material distribution holes, of the opening. The device has the advantages that the scaling condition of materials prone to scaling in the distribution process is relieved, uniform distribution of slurry and process washing water is facilitated, and the filtering performance and the process quality of the materials are guaranteed.

Description

Technical Field

[0001] This application relates to the field of wet phosphoric acid process technology, and in particular to a complete set of equipment for fabric and washing in the wet phosphoric acid process. Background Technology

[0002] The wet process for producing phosphoric acid is the main method for industrial production of phosphoric acid. Its main steps include grinding, reaction, filtration, and washing. The filtration step involves distributing the reacted slurry onto the filter cloth of a vacuum belt filter using a cloth distribution device. The mother liquor is then drawn away through the filter cloth using vacuum suction to achieve filtration and separation. The washing step involves distributing the process wash water onto the filter cake of the vacuum belt filter through a wash water distribution device for multiple countercurrent washings to recover the phosphoric acid entrained in the filter cake.

[0003] Currently, the structure of most washing and water distribution devices is the same as that of material distribution devices, mainly in two ways: one is to use a single-hole central feed followed by distribution through baffles, and the other is to allow material to enter from one side and then distribute it through multiple holes. Regardless of the method, the slurry or process wash water after the reaction in the wet-process phosphoric acid process is extremely prone to scaling, and uneven distribution is likely to occur when distributing such scaling liquids, which affects the filtration performance of the material and the quality of the process. Summary of the Invention

[0004] To help mitigate scaling of easily scaled materials during the distribution process, facilitate the uniform distribution of slurry and process washing water, and ensure the filtration performance and process quality of the materials, this application provides a complete set of equipment for cloth and washing in wet phosphoric acid process.

[0005] The technical solution provided in this application for a complete set of equipment for washing and cleaning fabrics used in a wet-process phosphoric acid phosphate production is as follows: A complete set of equipment for fabric washing in a wet-process phosphoric acid process includes: A cloth-spreading device is installed on the frame of a vacuum belt filter and is used to distribute the reacted slurry onto the filter cloth of the vacuum belt filter. A washing and water distribution device, comprising a primary washing mechanism, which is mounted on the frame of a vacuum belt filter and is used to distribute process water onto the filter cake of the vacuum belt filter. The primary washing mechanism and the fabric feeding device both include a distribution trough, a fabric feeding box, and a feed pipe. The distribution trough is mounted on the frame of the vacuum belt filter, and its length direction is parallel to the width direction of the vacuum belt filter. The distribution trough has a fabric feeding hole for the corresponding material to flow out. The fabric feeding box is set on the corresponding distribution trough, and the bottom wall of the fabric feeding box has an opening aligned with the center of the corresponding distribution trough. The bottom wall of the fabric feeding box is inclined, and the distance from the bottom wall of the fabric feeding box to the bottom wall of the distribution trough increases in the direction away from the fabric feeding hole. The feed pipe is connected to the fabric feeding box and is located on the side of the opening away from the fabric feeding hole.

[0006] Preferably, in the fabric distribution device, multiple fabric holes are spaced apart along the length of the distribution groove. The lower inner wall of each fabric hole is flush with the inner bottom wall of the corresponding distribution groove. The cross-sectional area of ​​the fabric hole located in the middle of the distribution groove is larger than the cross-sectional area of ​​the fabric holes located on both sides of the distribution groove.

[0007] Preferably, during equipment operation, the liquid level in the distribution tank of the fabric distribution device is higher than that in multiple fabric distribution holes.

[0008] Preferably, in the primary washing mechanism, the fabric hole on the distribution tank is opened along the length direction of the corresponding distribution tank, the lower inner wall of the fabric hole is higher than the inner bottom wall of the corresponding distribution tank, and the lower inner wall of the fabric hole is designed with serrations to form a serrated overflow weir.

[0009] Preferably, the inner diameter of the feed pipe increases in the direction close to the corresponding fabric box.

[0010] Preferably, the feed pipe is arranged vertically, and the angle between the bottom wall of the fabric box and the horizontal plane is 45°.

[0011] Preferably, the washing and water distribution device further includes a tail-stage washing mechanism, which is located on the side of the first-stage washing mechanism away from the cloth-distributing device. The sequential arrangement direction of the tail-stage washing mechanism, the first-stage washing mechanism, and the cloth-distributing device is opposite to the conveying direction of the vacuum belt filter. The tail-stage washing mechanism includes two water distribution pipes, which are respectively mounted on the frame of the vacuum belt filter. The water distribution pipes are provided with a group of eyelets for the washing water to flow out. Either end of the water distribution pipe is used to communicate with external process washing water. The water flow directions of the two water distribution pipes are opposite.

[0012] Preferably, each of the water distribution pipes has two sets of eye holes, and the arrangement direction of the two sets of eye holes on the water distribution pipes is perpendicular to the length direction of the water distribution pipes. Each set of eye holes includes multiple water outlet holes, and the multiple water outlet holes in each set of eye holes are arranged sequentially along the length direction of the water distribution pipes. The opening directions of the water outlet holes in the two sets of eye holes are perpendicular to each other.

[0013] Preferably, the size of the water outlet in each group of eye holes increases along the water flow direction of the corresponding water distribution pipe.

[0014] Preferably, the washing and water distribution device further includes an intermediate washing mechanism, which is located between the primary washing mechanism and the secondary washing mechanism. The intermediate washing mechanism has the same structural design as the primary washing mechanism. The process washing water of the intermediate washing mechanism is the filtered water recovered from the secondary washing mechanism, and the process washing water of the primary washing mechanism is the filtered water recovered from the intermediate washing mechanism.

[0015] In summary, this application includes the following beneficial technical effects: During operation, the slurry after the reaction process enters the distribution box of the distribution device through the feed pipe, while the process washing water enters the corresponding distribution box through the feed pipe of the primary washing mechanism. The reacted liquid and process washing water quickly enter the corresponding distribution tank along the inclined bottom wall of the corresponding distribution box. Then, the reacted liquid is distributed onto the filter cloth of the vacuum belt filter through the distribution holes of the corresponding distribution tank. The vacuum suction at the distribution device forms a filter cake on the filter cloth of the vacuum belt filter. The washing water is distributed onto the filter cake of the vacuum belt filter through the distribution holes of the corresponding distribution tank to wash the filter cake and further recover the entrained substances in the filter cake. Phosphoric acid; In this application, since the feed pipe, distribution tank and feed hole in the feeding device and the first washing mechanism are arranged sequentially, the flow of the liquid is avoided by the guide of the bottom wall of the feeding box. For liquids that are prone to scaling, the scaling caused by the deceleration process of the flow deflection can be reduced. In addition, the feed pipe directly guides the liquid to the bottom wall of the feeding box, which can accelerate the flow of the liquid and slow down the scaling of the liquid on the bottom wall of the feeding box. This makes it less likely that there will be more liquid in non-scaling areas and less liquid in scaling areas. This is conducive to the uniform distribution of materials that are prone to scaling, reduces the thickness difference of the filter cake on the filter cloth of the vacuum belt filter, and ensures the filtration performance and process quality of the material. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.

[0017] Figure 2 This is a schematic diagram of the overall structure of the fabric-laying device in the embodiments of this application.

[0018] Figure 3 This is a cross-sectional view of the overall structure of the fabric-laying device in the embodiments of this application.

[0019] Figure 4 This is a schematic diagram of the overall structure of the primary or intermediate washing mechanism in the embodiments of this application.

[0020] Figure 5This is a schematic diagram of the overall structure of the tail-stage washing mechanism in the embodiments of this application, wherein the arrows indicate the water flow direction of the corresponding water distribution pipes.

[0021] Figure 6 This is a cross-sectional view of the overall structure of the water distribution pipe in the embodiment of this application.

[0022] Explanation of reference numerals in the attached drawings: 1. Fabric distribution device; 2. Vacuum belt filter; 3. Washing water distribution device; 31. First-stage washing mechanism; 32. Tail-stage washing mechanism; 321. Water distribution pipe; 33. Intermediate-stage washing mechanism; 4. Distribution trough; 5. Fabric box; 6. Feed pipe; 7. Fabric hole; 8. Opening; 9. Serrated edge; 10. Eyelet group; 101. Water outlet. Detailed Implementation

[0023] In the wet-process phosphoric acid production, the uniformity of material distribution on the filter cloth of a vacuum belt filter directly affects the filtration performance. The greater the difference in filter cake thickness on the filter cloth, the worse the filtration performance. For example, an excessively thick filter cake can lead to insufficient vacuum suction, excessive liquid content in the filter cake, and low yield of the liquid phase product; while an excessively thin filter cake can cause vacuum leakage, wasting energy. Furthermore, significant differences in filter cake thickness also affect the effectiveness of the subsequent washing process. Therefore, there is an urgent need for a complete set of cloth and washing equipment capable of uniformly distributing easily fouling materials.

[0024] The following combination Figures 1-6 This application will be described in further detail.

[0025] This application discloses a complete set of equipment for fabric washing in a wet-process phosphoric acid process. (Refer to...) Figure 1 The wet-process phosphoric acid process uses a complete set of cloth and washing equipment, including a cloth distribution device 1 and a washing and water distribution device 3. The cloth distribution device 1 is mounted on the frame of a vacuum belt filter 2 and is used to distribute the reacted slurry onto the filter cloth of the vacuum belt filter 2. The washing and water distribution device 3 includes a primary washing mechanism 31, which is also mounted on the frame of the vacuum belt filter 2 and is used to distribute the process washing water onto the filter cake of the vacuum belt filter 2. Specifically, the primary washing mechanism 31 is located on the side of the cloth distribution device 1 near the output of the vacuum belt filter 2. The vacuum belt filter 2 is existing technology, and its structure and principle will not be described in detail here.

[0026] Reference Figure 1 and Figure 2To improve the uniformity of the fabric and water distribution, both the primary washing mechanism 31 and the fabric device 1 include a distribution trough 4, a fabric box 5, and a feed pipe 6. The distribution trough 4 is a rectangular trough, and supports (not shown in the figure) are fixedly installed on opposite sides of the distribution trough 4. The distribution trough 4 is fixedly mounted on the frame of the vacuum belt filter 2 by the supports on opposite sides. The length direction of the distribution trough 4 is parallel to the width direction of the vacuum belt filter 2. The length of the distribution trough 4 is adapted to the width of the filter cloth on the vacuum belt filter 2. The distribution trough 4 has a fabric hole 7 for supplying liquid. The fabric hole 7 is located on the side of the corresponding distribution trough 4 away from the output of the vacuum belt filter 2, so as to facilitate the distribution of liquid to the filter cloth of the vacuum belt filter 2.

[0027] Reference Figure 2 and Figure 3 The fabric box 5 is fixedly connected to the upper end of the corresponding distribution groove 4 by screws. Specifically, the fabric box 5 is located in the middle of the corresponding distribution groove 4, and the length of the fabric box 5 is less than one-quarter of the length of the distribution groove 4. An opening 8 is provided on the bottom wall of the fabric box 5, and the opening 8 is aligned with the middle bottom wall of the corresponding distribution groove 4. The bottom wall of the fabric box 5 is inclined, and the distance from the bottom wall of the fabric box 5 to the bottom wall of the corresponding distribution groove 4 increases in the direction away from the fabric hole 7. The feed pipe 6 is connected to the corresponding fabric box 5, and the feed pipe 6 is located on the side of the corresponding opening 8 away from the fabric hole 7.

[0028] During operation, the slurry after the reaction process enters the slurry box 5 of the slurry distribution device 1 through the feed pipe 6, while the process washing water enters the corresponding slurry box 5 through the feed pipe 6 of the primary washing mechanism 31. The reacted liquid and process washing water quickly enter the corresponding distribution tank 4 along the inclined bottom wall of the corresponding slurry box 5. Then, the reacted liquid is distributed onto the filter cloth of the vacuum belt filter 2 through the slurry holes 7 of the corresponding distribution tank 4. Then, the vacuum suction at the slurry distribution device 1 forms a filter cake on the filter cloth of the vacuum belt filter 2, while the process washing water is distributed onto the filter cake of the vacuum belt filter 2 through the slurry holes 7 of the corresponding distribution tank 4 to wash the filter cake. To further recover phosphoric acid entrained in the filter cake, in this application, since the feed pipe 6, distribution tank 4, and feed hole 7 in the feeding device 1 and the primary washing mechanism 31 are arranged sequentially, the liquid is guided by the bottom wall of the feeding box 5, avoiding flow obstruction. For liquids prone to scaling, this reduces scaling caused by the deceleration process of flow obstruction. Furthermore, the feed pipe 6 directly guides the liquid to the bottom wall of the feeding box 5, which can accelerate the flow of the liquid and slow down scaling on the bottom wall of the feeding box 5. This makes it less likely that there will be more liquid in non-scalded areas and less liquid in scalded areas, which is conducive to the uniform distribution of materials prone to scaling, reduces the difference in filter cake thickness, and ensures the filtration performance and process quality of the material.

[0029] Reference Figure 2 and Figure 3The feed pipe 6 is set vertically, and the angle between the bottom wall of the distribution box 5 and the horizontal plane is 45°, so that the angle between the feed pipe 6 and the side of the bottom wall of the distribution box 5 near the distribution tank 4 is 135°. This allows the liquid to flow quickly along the bottom wall of the distribution box 5, which not only avoids the liquid from being blocked, but also accelerates the flow rate of the liquid on the bottom wall of the distribution box 5. This helps to reduce the scaling of the liquid on the bottom wall of the distribution box 5 and is more conducive to the uniform distribution of the liquid on the bottom wall of the distribution box 5.

[0030] Reference Figure 3 The inner diameter of the feed pipe 6 increases gradually in the direction close to the corresponding distribution box 5. Specifically, the inner diameter of the feed pipe 6 is set as needed. As the liquid enters the feed pipe 6, the inner diameter gradually increases, which can slightly reduce the flow velocity of the liquid to the bottom wall of the distribution box 5. Optimally, the flow velocity is reduced by 20%, reducing the liquid flow velocity to 2-3 m / s, reducing the impact on the bottom wall of the distribution box 5 caused by excessive flow velocity, reducing liquid splashing, and making it more conducive to the uniform distribution of the liquid in the distribution box 5.

[0031] Reference Figure 1 and Figure 2 To facilitate uniform distribution of the feed liquid from the distribution tank 4, multiple distribution holes 7 are spaced apart along the length of the distribution tank 4 in the distribution device 1. The spacing between adjacent distribution holes 7 can be set as needed to ensure that the feed liquid flowing out from the multiple distribution holes 7 forms a uniform water curtain. During equipment operation, the liquid level in the distribution tank 4 of the distribution device 1 is higher than the multiple distribution holes 7, thus facilitating the uniform flow of the feed liquid from the multiple distribution holes 7. Furthermore, since the slurry after reaction in the wet-process phosphoric acid process easily forms gypsum crystals, by flushing the lower inner wall of the distribution hole 7 with the inner bottom wall of the distribution tank 4, the feed liquid can flow out of the distribution tank 4 in a timely manner, effectively preventing the slurry after reaction from settling in the distribution tank 4 and reducing scaling on the bottom wall of the distribution tank 4.

[0032] Reference Figure 1 and Figure 2 The width of the multiple fabric holes 7 in the fabric feeding device 1 is the same. The cross-sectional area of ​​the fabric hole 7 located in the middle of the distribution groove 4 is greater than that of the fabric holes 7 located on both sides of the distribution groove 4, and the length of the fabric hole 7 located in the middle of the distribution groove 4 is greater than that of the fabric holes 7 located on both sides of the distribution groove 4. Specifically, the length of the fabric holes 7 in the fabric feeding device 1 decreases from the middle to both sides.

[0033] During equipment operation, the liquid level in the distribution tank 4 of the material distribution device 1 is higher than that in the multiple material distribution holes 7. Under the fluid boundary layer separation effect, a boundary layer is generated when the material impacts the surface. The boundary layer is thinnest near the direct impact point. As the thickness of the boundary layer increases towards both sides, the fluid viscous resistance is enhanced, resulting in more material being retained in the two sides. That is, when the multiple material distribution holes 7 in the material distribution device 1 are of uniform size, less liquid flows out of the material distribution holes 7 located in the middle. Therefore, by designing the material distribution holes 7 in the middle area to be larger, the problem of less liquid distribution in the middle can be effectively reduced.

[0034] Reference Figure 1 , Figure 2 and Figure 4 Since the liquid entering the feeding device 1 is a uniform slurry with little particle size difference after reaction, and the temperature is high, it has not undergone sedimentation and therefore there is no flaky gypsum. When the liquid in the corresponding distribution tank 4 is distributed, there is no flaky gypsum blocking the corresponding feeding hole 7. However, the washing water of the first-stage washing mechanism 31 is the recycled filtered water from the subsequent washing. The recycled filtered water from the subsequent washing is prone to flaky scaling when stored in the corresponding collection chamber. Directly pumping the filtered water from the subsequent washing to the feed pipe 6 of the first-stage washing mechanism 31 makes the process washing water at the first-stage washing mechanism 31 extremely prone to blocking the feeding hole 7 in the distribution tank 4, just like in the feeding device 1. Moreover, the way the feeding hole 7 in the feeding device 1 is opened makes it impossible to observe the internal situation. To solve this problem, the fabric distribution hole 7 in the distribution tank 4 of the primary washing mechanism 31 is opened along the length direction of the corresponding distribution tank 4. That is, the fabric distribution hole 7 in the primary washing mechanism 31 is an integral notch opened along the length direction of the corresponding distribution tank 4. The lower inner wall of the fabric distribution hole 7 is higher than the inner bottom wall of the corresponding distribution tank 4, and the lower inner wall of the fabric distribution hole 7 is designed with serrations 9 along its own length direction to form a serrated overflow weir. In the primary washing mechanism 31, the fabric distribution hole 7 is designed as a serrated overflow weir. On the one hand, it is convenient to observe the situation inside the corresponding distribution tank 4. On the other hand, it makes it less likely for the process washing water entering the distribution tank 4 to clog the fabric distribution hole 7.

[0035] Reference Figure 1To further improve the washing effect, the washing water distribution device 3 also includes a tail-stage washing mechanism 32 and an intermediate-stage washing mechanism 33. The tail-stage washing mechanism 32 is located on the side of the first-stage washing mechanism 31 away from the cloth-laying device 1, and the intermediate-stage washing mechanism 33 is located between the tail-stage washing mechanism 32 and the first-stage washing mechanism 31. Specifically, the cloth-laying device 1, the first-stage washing mechanism 31, the intermediate-stage washing mechanism 33, and the tail-stage washing mechanism 32 are arranged sequentially and at intervals along the conveying direction of the vacuum belt filter 2, that is, the direction in which the tail-stage washing mechanism 32, the intermediate-stage washing mechanism 33, the first-stage washing mechanism 31, and the cloth-laying device 1 are arranged sequentially is opposite to the conveying direction of the vacuum belt filter 2. Through the arrangement of the first-stage washing mechanism 31, the intermediate-stage washing mechanism 33, and the tail-stage washing mechanism 32, the washing water distribution device 3 forms a three-stage countercurrent washing.

[0036] Reference Figure 1 In this system, the process washing water of the tail-stage washing mechanism 32 is clean water or process water with extremely low solids content that is not prone to scaling. The process washing water of the intermediate-stage washing mechanism 33 is filtered water recovered from the vacuum at the tail-stage washing mechanism 32, and the process washing water of the first-stage washing mechanism 31 is filtered water recovered from the vacuum at the intermediate-stage washing mechanism 33. This helps to reduce water consumption while improving the washing effect. In other embodiments, the washing water distribution device 3 can also be designed as a four-stage countercurrent washing system, a five-stage countercurrent washing system, etc., as needed.

[0037] Reference Figure 1 and Figure 5 Specifically, to facilitate the uniform distribution of cleaning washing water in the tail-stage washing mechanism 32, the tail-stage washing mechanism 32 includes two water distribution pipes 321. The two water distribution pipes 321 are arranged at intervals along the conveying direction of the vacuum belt filter 2. Each water distribution pipe 321 has a support frame (not shown in the figure) fixed on both sides. Each water distribution pipe 321 is fixed on the frame of the vacuum belt filter 2 by the support frames at both ends. The length direction of the water distribution pipe 321 is parallel to the width direction of the vacuum belt filter 2. The length of the water distribution pipe 321 is adapted to the width of the filter cloth of the vacuum belt filter 2. An eyelet group 10 for the washing water to flow out is opened on the side of the water distribution pipe 321 facing the filter cloth of the vacuum belt filter 2. Either end of the water distribution pipe 321 is used to communicate with external process washing water. The water flow directions of the two water distribution pipes 321 are opposite.

[0038] During operation, the external cleaning process washing water is simultaneously introduced into two water distribution pipes 321. The two water distribution pipes 321 have opposite water flow directions in the width direction of the vacuum belt filter 2. This forward and reverse water flow through the two water distribution pipes 321 helps to reduce uneven water distribution caused by unidirectional water flow, ensuring washing effect and process quality.

[0039] Reference Figure 5 and Figure 6To further improve the washing effect of the tail-stage washing mechanism 32, two sets of eye holes 10 are provided on each water distribution pipe 321. The arrangement direction of the two sets of eye holes 10 on the water distribution pipe 321 is perpendicular to the length direction of the water distribution pipe 321. Each set of eye holes 10 includes multiple water outlet holes 101. The multiple water outlet holes 101 in each set of eye holes 10 are arranged sequentially at intervals along the length direction of the corresponding water distribution pipe 321. The opening direction of the water outlet holes 101 in the two sets of eye holes 10 is perpendicular to each other. Specifically, the two sets of eye holes 10 are symmetrically arranged along the vertical axis.

[0040] Two drain holes 101 are made at 45° on the corresponding water distribution pipe 321, so that the water outlet directions of the two drain holes 101 are 90°. During operation, the clean washing water will wash the filter cake in two directions, which will greatly help to improve the washing rate.

[0041] Reference Figure 6 Because the pressure is higher near the water inlet side in the water distribution pipe 321, in order to further improve the water distribution uniformity of the tail washing mechanism 32, the size of multiple water outlet holes 101 in each group of eye holes 10 increases along the water flow direction of the corresponding water distribution pipe 321, thereby further ensuring the washing effect.

[0042] Reference Figure 1 The intermediate washing mechanism 33 has the same structural design as the first washing mechanism 31. The filtered water extracted by the tail washing mechanism 32 is used as the washing water of the intermediate washing mechanism 33. Then, it flows through the feed pipe 6 of the intermediate washing mechanism 33 to the bottom wall of the fabric box 5 for the first distribution. Then, it is distributed for the second time through the sawtooth overflow weir of the corresponding distribution groove 4 to achieve uniform water distribution and ensure washing effect while reducing water volume.

[0043] The implementation principle of this application embodiment is as follows: During operation, the slurry after the reaction process enters the slurry box 5 of the slurry distribution device 1 through the feed pipe 6 of the slurry distribution device 1. Clean process washing water is input through different ends of two water distribution pipes 321. Then, the slurry after the reaction process is distributed to the corresponding distribution tank 4 along the inclined bottom wall of the slurry box 5 in the slurry distribution device 1. The liquid level in the distribution tank 4 quickly rises above the multiple slurry holes 7. Then, the speed at which the slurry enters the slurry distribution device 1 is adjusted to the required flow rate. The slurry is distributed onto the filter cloth of the vacuum belt filter 2 through the multiple slurry holes 7. The vacuum belt filter 2 at the location of the slurry distribution device 1 forms a filter cake on the filter cloth of the vacuum belt filter 2 by vacuum suction of the mother liquor.

[0044] The cleaning water entering the two water distribution pipes 321 is evenly distributed onto the filter cake of the vacuum belt filter 2 through two rows of mutually perpendicular water outlets 101 on the corresponding water distribution pipes 321. The filtrate from the tail-stage washing mechanism 32 is vacuum-extracted from the vacuum chamber of the vacuum belt filter 2 and pumped to the feed pipe 6 of the intermediate-stage washing mechanism 33. It then flows to the bottom wall of the corresponding material distribution box 5 for initial distribution, followed by secondary distribution through the sawtooth overflow weir of the corresponding distribution trough 4, thus achieving a thorough cleaning of the vacuum belt filter cake. The filter cake on filter 2 is rinsed, and then the filtrate from intermediate washing mechanism 33 is extracted through the vacuum chamber of vacuum belt filter 2 and pumped to feed pipe 6 of primary washing mechanism 31. Then the washing water enters the corresponding cloth box 5 and quickly enters the corresponding distribution tank 4 along the inclined bottom wall of the corresponding cloth box 5. Then it is distributed on the filter cake of vacuum belt filter 2 from the sawtooth overflow weir of the corresponding distribution tank 4, forming a three-stage countercurrent washing, which can reduce water volume, ensure washing effect, and further recover phosphoric acid entrained in the filter cake.

[0045] In this application, since the feed pipe 6, distribution tank 4, and feed hole 7 in the feeding device 1, the primary washing mechanism 31, and the intermediate washing mechanism 33 are arranged sequentially, the guide wall of the feeding box 5 prevents the liquid from being obstructed. For liquids prone to scaling, this reduces scaling caused by the deceleration process due to obstruction. Furthermore, the feed pipe 6 directly guides the liquid to the bottom wall of the feeding box 5, which accelerates the flow of the liquid and reduces scaling on the bottom wall of the feeding box 5, preventing the situation where more liquid is distributed in areas without scaling and less in areas with scaling. At the same time, the liquid in the distribution tank 4 of the feeding device 1 is distributed through the multiple feed holes 7, which are designed with a specific structure and size relationship. The design of the sawtooth overflow weirs at the first-stage washing mechanism 31 and the intermediate-stage washing mechanism 33 helps to prevent scale in the washing water from clogging the cloth holes 7, ensuring uniform distribution while facilitating observation by operators. The design of the clean washing water at the tail-stage washing mechanism 32 through two water distribution pipes 321 and water outlet 101 facilitates uniform water distribution, ensuring washing effect, and thus promoting the uniform distribution of materials prone to scaling. This reduces the difference in filter cake thickness on the vacuum belt filter 2, greatly balancing the stability and uniformity of filter cake liquid content, and to a certain extent ensuring the filtration performance and process quality of the material.

[0046] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A complete wet-process phosphoric acid plant for feeding and washing, characterized in that, The utility model relates to a kind of primary washing mechanism and distribution device for vacuum belt filter, including: Distribution device (1) is arranged on the rack of vacuum belt filter (2), for the slurry after reaction is distributed on the filter cloth of vacuum belt filter (2); Washing water distribution device (3) includes first-stage washing mechanism (31), and the first-stage washing mechanism (31) is arranged on the rack of vacuum belt filter (2), for process water is distributed on the filter cake of vacuum belt filter (2); The first-stage washing mechanism (31) and distribution device (1) both include distribution tank (4), distribution box (5) and feed pipe (6), the distribution tank (4) is used to be erected on the rack of vacuum belt filter (2), the length direction of the distribution tank (4) is parallel to the width direction of vacuum belt filter (2), the distribution tank (4) has distribution hole (7) for corresponding material flow on it, the distribution box (5) is arranged on corresponding distribution tank (4), the bottom wall of the distribution box (5) is provided with opening (8), the opening (8) is aligned with the middle part of corresponding distribution tank (4), the bottom wall of the distribution box (5) is in inclined state, the distance from the bottom wall of the distribution box (5) to the bottom wall of distribution tank (4) increases towards the direction away from distribution hole (7), the feed pipe (6) is connected on corresponding distribution box (5), and the feed pipe (6) is located on the side away from distribution hole (7) of opening (8).

2. A complete equipment for cloth and washing of wet-process phosphoric acid according to claim 1 characterized in that: The distribution hole (7) on the distribution tank (4) in the distribution device (1) is spaced apart and provided with multiple along the length direction of the distribution tank (4), the lower inner wall of the distribution hole (7) is flush with the inner bottom wall of corresponding distribution tank (4), and the cross-sectional area of the distribution hole (7) located at the middle position of the distribution tank (4) is greater than that of the distribution hole (7) located at both sides of the distribution tank (4).

3. A complete equipment for cloth and washing of wet-process phosphoric acid according to claim 2, characterized in that: When the equipment is running, the liquid level in the distribution tank (4) in the distribution device (1) is higher than multiple distribution holes (7).

4. A complete equipment for cloth and washing of wet-process phosphoric acid according to claim 2, characterized in that: The distribution hole (7) on the distribution tank (4) in the first-stage washing mechanism (31) is provided along the length direction of corresponding distribution tank (4), the lower inner wall of the distribution hole (7) is higher than the inner bottom wall of corresponding distribution tank (4), and the lower inner wall of the distribution hole (7) is designed with sawtooth (9) to form sawtooth overflow weir.

5. A complete equipment for cloth and washing of wet-process phosphoric acid according to claim 1 characterized in that: The inner diameter of the feed pipe (6) increases along the direction close to corresponding distribution box (5).

6. A complete equipment for cloth and washing of wet-process phosphoric acid according to claim 1 characterized in that: The feed pipe (6) is arranged along the vertical direction, and the angle between the bottom wall of the distribution box (5) and the horizontal plane is 45°.

7. A complete equipment for wet-process phosphoric acid according to any one of claims 1-6, characterized in that it comprises: The washing water distribution device (3) further comprises a tail-stage washing mechanism (32) located on the side of the head-stage washing mechanism (31) away from the material distribution device (1), the tail-stage washing mechanism (32), the head-stage washing mechanism (31) and the material distribution device (1) are arranged in sequence in a direction opposite to the conveying direction of the vacuum belt filter (2), the tail-stage washing mechanism (32) comprises two water distribution pipes (321) arranged on the frame of the vacuum belt filter (2) respectively, a group of eye holes (10) for washing water outflow are arranged on the water distribution pipe (321), and any end of the water distribution pipe (321) is connected with an external process washing water; the water distribution directions of the two water distribution pipes (321) are opposite.

8. A complete equipment for cloth and washing of wet-process phosphoric acid according to claim 7, characterized in that: Each water distribution pipe (321) is provided with two groups of eye hole groups (10), the arrangement directions of the two groups of eye hole groups (10) on the water distribution pipe (321) are perpendicular to the length direction of the water distribution pipe (321), each group of eye hole groups (10) comprises a plurality of water outlet holes (101), and the plurality of water outlet holes (101) in each group of eye hole groups (10) are arranged in sequence along the length direction of the water distribution pipe (321); the opening directions of the water outlet holes (101) in the two groups of eye hole groups (10) are perpendicular to each other.

9. A complete equipment for cloth and washing of wet-process phosphoric acid according to claim 8, characterized in that: The size of the water outlet hole (101) in each group of eye hole groups (10) increases along the water distribution direction of the corresponding water distribution pipe (321).

10. A complete equipment for cloth and washing of wet-process phosphoric acid according to claim 7, characterized in that: The washing water distribution device (3) further comprises an intermediate-stage washing mechanism (33) located between the head-stage washing mechanism (31) and the tail-stage washing mechanism (32), the intermediate-stage washing mechanism (33) has the same structure design as the head-stage washing mechanism (31), the process washing water of the intermediate-stage washing mechanism (33) is the filtered water recovered at the tail-stage washing mechanism (32), and the process washing water of the head-stage washing mechanism (31) is the filtered water recovered at the intermediate-stage washing mechanism (33).

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