Polyaluminum chloride refining method and device
By recycling unreacted solid impurities and seamlessly integrating piston-type filter presses, the problems of resource waste and discontinuous production processes in polyaluminum chloride production have been solved, achieving efficient and stable product production.
Patent Information
- Application Number
- CN202511187384.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-25
- Publication Date
- 2025-11-14
AI Technical Summary
Traditional polyaluminum chloride production suffers from problems such as resource waste, low precision in basicity adjustment, poor product stability, and discontinuous production process.
A method for refining polyaluminum chloride is adopted, in which unreacted solid impurities are returned to the reactor to participate in the reaction again, the basicity is controlled at 40%-90%, and a piston-type filter press plate is used in conjunction with a translation drive mechanism to achieve seamless connection of filter press, liquid replenishment and slag discharge processes, avoiding downtime for cleaning filter residue.
It improves raw material utilization, reduces product performance fluctuations, shortens production cycles, enhances equipment space utilization and production efficiency, and extends the service life of filter media.
Smart Images
Figure CN120943283A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polyaluminum chloride production technology, specifically to a method and apparatus for refining polyaluminum chloride. Background Technology
[0002] Polyaluminum chloride (PAC) is an inorganic polymeric coagulant between AlCl3 and Al(OH)3. It is usually made from raw materials such as aluminum ash and bauxite through acid dissolution and polymerization reactions. Its structure is a polynuclear hydroxyl complex. It has the characteristics of wide pH range adaptability, strong coagulation effect and low dosage. It is widely used in the purification of drinking water, industrial wastewater and other water bodies. Through adsorption, bridging and other effects, it causes suspended particles and colloids in the water to coagulate and precipitate, thereby achieving the purpose of purifying water quality.
[0003] In traditional production processes, polyaluminum chloride is often prepared by reacting industrial aluminum hydroxide with hydrochloric acid and then directly discharging the product. This has the following problems: unreacted raw materials are directly discharged as filter residue, resulting in resource waste; the basicity adjustment accuracy is low, and the product stability is poor.
[0004] Furthermore, when using a traditional plate and frame filter press to filter and refine the reaction liquid, the production process is interrupted and the production cycle is extended because the machine needs to be stopped and the filter residue needs to be cleaned manually after filtration. This results in low operational continuity and consequently low production efficiency. Summary of the Invention
[0005] The purpose of this invention is to provide a method and apparatus for refining polyaluminum chloride to solve the technical problems mentioned in the background art.
[0006] To achieve the above objectives, the present invention provides the following technical solution.
[0007] A method for purifying polyaluminum chloride specifically includes the following steps: S1. Preparation of reaction solution: Add 100 parts by mass of industrial aluminum hydroxide to the reaction vessel, add 300-350 parts by mass of water and stir to disperse, then add 420-440 parts by mass of hydrochloric acid, pass steam to heat to 95±5℃, and react at normal pressure for 2±0.5 hours to obtain the primary reaction solution. S2, Pressure Filtration Purification: The primary reaction liquid is introduced into the purification device for pressure filtration to remove unreacted solid impurities and obtain a clear filtrate. The filter residue is returned to the reaction vessel to participate in the reaction again. S3. Adjusting basicity: Transfer the filtrate to the adjustment tank, add sodium aluminate solution, stir and react for 1-1.5 hours, and control the basicity at 40%-90% to obtain polyaluminum chloride liquid product. Among them, the purity of industrial aluminum hydroxide is ≥98%, the hydrochloric acid concentration is 30%-32%, and the aluminum oxide content in sodium aluminate solution is 10%-15%.
[0008] This invention also provides a polyaluminum chloride refining apparatus, applied in the above-mentioned polyaluminum chloride refining method. The refining apparatus includes a base, a side frame fixed above and behind the base, and a filter press cylinder fixed above the base by a support frame. A piston-type filter press disc is fitted inside the horizontally arranged filter press cylinder, which is open at both ends. A feed inlet is located near the center of the filter press cylinder. A guide rod is installed through the piston-type filter press disc, with both ends extending to the outside of the filter press cylinder. The side frame is equipped with a mechanism for driving the guide rod to move horizontally. The filter press cylinder has a translation drive mechanism; filter plates and collection hoods are movably mounted on both sides of the guide rod, and the filter plates and collection hoods on the same side form an end cap structure; the filter plates are fixed to the collection hoods on the same side, and a collection space is formed between them; the bottom of the collection hoods has a discharge port that communicates with the collection space; both filter plates are equipped with an opening and closing drive mechanism, and both sides of the filter press cylinder are equipped with a linkage mechanism. The opening and closing drive mechanism and the linkage mechanism on the same side cooperate with each other so that the linkage end cap structure can be adjusted to open and close during the translation drive mechanism drives the guide rod to translate.
[0009] Preferably, the feed inlet on the filter press cylinder is connected to a feed pipe, the end of which is connected to the discharge section of the reactor, and a feed valve is installed on the feed pipe; the discharge outlets on both sides of the material collection hood are connected to discharge pipes, the end of which is connected to the feed section of the regulating tank, and a discharge valve is installed on each discharge pipe.
[0010] Preferably, the translation drive mechanism includes a guide frame, a first threaded rod, a drive motor A, a first nut seat, and a traction arm; the guide frame is fixed to the side of the side frame and arranged parallel to the filter cylinder, and the drive motor A is fixed to one end of the guide frame; the first threaded rod is rotatably mounted on the guide frame, and one end is fixedly connected to the output shaft of the drive motor A; the first nut seat is threadedly fitted onto the first threaded rod, a limit rod is fixed on the guide frame, and the first nut seat is slidably fitted onto the limit rod; a fixed seat is fixed to the top of the first nut seat, and a traction arm is fixed to the side of the fixed seat, with the other end of the traction arm fixedly connected to one end of the guide rod.
[0011] Preferably, side seats are fixed on both sides of the collection hood, and first sliding rods are fixed on the side seats; first sleeves are fixed on the outer wall of the filter press near both ends, and the first sliding rods are slidably installed in the first sleeves one by one; the opening and closing drive mechanism includes a mounting seat, a second threaded rod, and a second nut seat; the top of both collection hoods is fixed with a second nut seat; mounting seats are fixed on both sides of the filter press, and second threaded rods are rotatably installed through the mounting seats; the second nut seat is threadedly fitted onto the second threaded rod on the corresponding side; the linkage mechanism is used to link the rotation of the second threaded rod when the first nut seat moves.
[0012] Preferably, the linkage mechanism includes a worm, a worm wheel, and a gear; brackets are fixed to both ends of the outer wall of the filter press cylinder, and the worm is rotatably mounted on the brackets; worm wheels are fixed to the ends of the two second threaded rods that are close to each other, and the worm wheels mesh with the worms on the same side; a gear is fixed to one end of each of the two worms; an L-shaped arm is fixed to the top of the fixed seat, and a rack is fixed to the end of the L-shaped arm, which meshes with the two gears respectively; wherein, when the filter plate and the end face of the filter press cylinder are tightly fitted to achieve a seal, the rack separates from the gear.
[0013] Preferably, sealing rings are fixed on the surfaces of the two filter plates that are close to each other; air inlets are provided on the top of the two collection hoods, and one-way valves are installed in the two air inlets.
[0014] Preferably, the guide rod is rotatably connected to the piston-type filter press disc; the guide rod is movably connected to the filter plate and the collection hood; a scraping drive mechanism is provided on the side of one side of the collection hood, which is used to drive the guide rod to rotate; a scraping mechanism is provided on both filter plates; when the guide rod rotates, it can drive the scraping mechanism to scrape off the filter residue adhering to the filter plate.
[0015] Preferably, the scraping mechanism includes a scraper plate; two limiting grooves are symmetrically provided on the guide rod; an annular sleeve is rotatably installed through the center of each of the two filter plates, and a limiting block is fixed on the inner edge wall of each annular sleeve, with the limiting block correspondingly limited and locked in the limiting groove on the same side; a scraper plate is fixed on the end of each of the two annular sleeves that is close to each other; the scraper plate is in movable contact with the surface of the filter plate on the same side.
[0016] Preferably, the scraping drive mechanism includes a drive motor B; a second seat is fixed on one of the side seats, and a second slide rod is slidably installed on the second seat; a frame plate is fixed to one end of the second slide rod, the drive motor B is fixed on the frame plate, and the output shaft of the drive motor B is fixedly connected to one end of the guide rod.
[0017] Compared with the prior art, the beneficial effects of the present invention are as follows.
[0018] This method involves returning the filter residue to the reactor for reuse, thereby enabling unreacted solid impurities to participate in the reaction in a cyclical manner. This improves raw material utilization, reduces resource waste, controls the basicity at 40%-90%, and reduces product performance fluctuations through controllable stoichiometry.
[0019] This device uses a translation drive mechanism to drive the guide rod, which in turn drives the piston-type filter press disc to move horizontally. In conjunction with the opening and closing drive mechanism and the linkage mechanism, the end cover structure opens and closes alternately, allowing for seamless connection of the filtration, liquid replenishment, and slag discharge processes. This eliminates the need for manual cleaning of filter slag during machine downtime, shortening the production cycle. At the same time, the piston-type filter press disc can move in both directions, completing two filtration operations in one reciprocating cycle. With the feed pipe feeding material in the middle of the filter press cylinder, uninterrupted material supply is achieved, improving the space utilization of the equipment and solving the problem of low efficiency in traditional filter presses operating in one direction.
[0020] This device uses an air intake module in a backflushing system consisting of an air inlet and a one-way valve. Combined with the negative pressure created by the movement of the piston-type filter press, external air is introduced into the collection space and backflushes the filter holes of the filter plate. This effectively removes solid impurities embedded in the filter holes, prevents clogging of the filter holes from causing an increase in filtration resistance, and extends the service life of the filter media. Furthermore, the scraper drive mechanism drives the guide rod to rotate, which in turn drives the scraper plate to rotate, thus scraping off the filter residue attached to the surface of the filter plate and helping to completely remove waste residue. Attached Figure Description
[0021] Figure 1 This is a schematic flowchart of the polyaluminum chloride refining method in this invention; Figure 2 This is a schematic diagram of the overall structure of the polyaluminum chloride refining apparatus provided by the present invention; Figure 3 This is a schematic diagram of a partial external structure of the filter press cylinder in this invention; Figure 4 for Figure 3 A partial cross-sectional schematic diagram of the structure shown; Figure 5 This is a schematic diagram of the end structure of the filter press cylinder in this invention; Figure 6 for Figure 5 The diagram shows a structure with an added filter plate. Figure 7 This is a schematic diagram showing the structural cooperation between the filter plate and the material collection hood in this invention; Figure 8 for Figure 7 The diagram shows a cross-sectional view of the structure. Figure 9 for Figure 8 Enlarged schematic diagram of the structure at point A in the diagram; Figure 10 This is a schematic diagram of the translation drive mechanism in this invention; Figure 11 This is a structural diagram of the opening and closing drive mechanism and the linkage mechanism; Figure 12 This is a schematic diagram of the overall structure of the polyaluminum chloride refining apparatus in Example 6; Figure 13 This is a schematic diagram of the scraping drive mechanism in the present invention; Figure 14 This is a schematic diagram of the scraping mechanism in this invention.
[0022] In the diagram: 1. Base; 11. Side frame; 12. Support frame; 2. Filter press cylinder; 21. Feed pipe; 211. Feed valve; 22. Piston-type filter press disc; 23. Guide rod; 231. Limiting groove; 3. Filter plate; 301. Side seat; 302. First sleeve; 303. First slide rod; 31. Collection hood; 32. Collection space; 33. Discharge pipe; 331. Discharge valve; 34. Sealing ring; 35. Air inlet; 36. One-way valve; 4. Translation drive mechanism; 41. Guide frame; 411. Limiting rod; 42. First threaded rod; 43. Drive motor A; 44. First nut seat; 45. Fixed seat; 46. Traction arm; 5. Opening and closing drive mechanism; 51. Mounting seat; 52. Second threaded rod; 53. Second nut seat; 6. Linkage mechanism; 61. Bracket; 62. Worm gear; 63. Worm wheel; 64. Gear; 65. L-shaped arm; 66. Rack; 7. Scraper drive mechanism; 71. Second sleeve; 72. Second slide bar; 73. Frame plate; 74. Drive motor B; 8. Scraper mechanism; 81. Annular sleeve; 82. Limiting block; 83. Scraper plate. Detailed Implementation
[0023] The embodiments of the present invention will now be described with reference to the accompanying drawings.
[0024] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection" and "installation" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, "connection" can be a direct connection or an indirect connection through an intermediate medium. "Fixed" means that the devices are connected to each other and their relative positional relationship remains unchanged after the connection. The directional terms mentioned in the embodiments of the present invention, such as "inner," "outer," "top," and "bottom," are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.
[0025] In this embodiment of the invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.
[0026] In this embodiment of the invention, "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0027] References to "one embodiment" or "some embodiments" as used in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the invention. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless otherwise specifically emphasized. Example 1
[0028] Please see Figure 1 This invention provides a method for purifying polyaluminum chloride, specifically including the following steps: S1. Weigh 100 kg of industrial aluminum hydroxide (purity 98%) according to the mass fraction, add 320 kg of water, stir and disperse, then add 430 kg of hydrochloric acid (concentration 31%), pass steam and heat to 95°C, react at normal pressure for 2 hours to obtain the primary reaction solution; S2. The primary reaction liquid is subjected to pressure filtration in the purification device to remove unreacted solid impurities, resulting in a clear filtrate. The filter residue is returned to the reactor to participate in the reaction again. S3. Transfer the clarified filtrate into the conditioning tank, add sodium aluminate solution (alumina content of 15%), stir for 1.2 hours, and control the basicity to 65% to obtain polyaluminum chloride liquid product.
[0029] It is worth noting that the polyaluminum chloride obtained above is a liquid. If a solid product is required, the liquid polyaluminum chloride is dried at 180°C to a moisture content of 8%, and then crushed to obtain the solid product. Example 2
[0030] Please see Figures 2-14 The present invention provides a polyaluminum chloride refining apparatus, which is applied in the polyaluminum chloride refining method in the above-mentioned Example 1, specifically in step two of the refining method, for pressure filtration of the primary reaction liquid to remove unreacted solid impurities in order to obtain a clear filtrate.
[0031] The refining device includes a base 1, a side frame 11, a support frame 12, and a filter press 2. The side frame 11 is fixed on the rear side above the base 1. The filter press 2 is arranged horizontally, and several support frames 12 are fixed on the outer wall of the filter press 2. The bottom end of each support frame 12 is fixed on the base 1.
[0032] The filter cylinder 2 is open at both ends, and a piston-type filter disc 22 is installed inside the filter cylinder 2. The outer edge of the piston-type filter disc 22 is tightly slidably fitted with the inner wall of the filter cylinder 2 to prevent liquid leakage. In addition, there is a feed port near the middle position on the filter cylinder 2. The feed port is connected to a feed pipe 21. The end of the feed pipe 21 is connected to the discharge part of the reactor, which is used to introduce the primary reaction liquid in the reactor into the filter cylinder 2 from the middle position. A feed valve 211 is installed on the feed pipe 21 to control the addition of the primary reaction liquid.
[0033] A guide rod 23 is installed through the piston filter press 22. Both ends of the guide rod 23 extend to the outside of the filter press cylinder 2. The side frame 11 is provided with a translation drive mechanism 4 for driving the guide rod 23 to move horizontally. The translation drive mechanism 4 can drive the guide rod 23 to move horizontally left and right, thereby driving the piston filter press 22 to move horizontally synchronously.
[0034] Filter plates 3 and collection hoods 31 are movably mounted on both sides of the guide rod 23, located on the filter cylinder 2. The filter plates 3 and collection hoods 31 on the same side form an end cap structure. The filter plates 3 and collection hoods 31 on the same side are fixed, and a collection space 32 is formed between them. The bottom of the collection hoods 31 has a discharge port that communicates with the collection space 32. The discharge ports are all connected to discharge pipes 33. The end of the discharge pipes 33 is connected to the feed section of the regulating tank, which is used to guide the clarified filtrate in the collection space 32 into the regulating tank. In addition, a discharge valve 331 is installed on the discharge pipes 33 to control the discharge of the clarified filtrate.
[0035] In addition, both filter plates 3 are equipped with opening and closing drive mechanisms 5, and both sides of the filter cylinder 2 are equipped with linkage mechanisms 6. The opening and closing drive mechanisms 5 and the linkage mechanisms 6 on the same side cooperate to adjust the opening and closing of the linkage end cover structure during the translation drive mechanism 4 drives the guide rod 23 to translate. Specifically, when the translation drive mechanism 4 drives the guide rod 23 to translate, driving the piston filter disc 22 to move from the side end of the filter cylinder 2 to the middle, the linkage end cover structure can move closer to the side end of the filter cylinder 2 under the cooperation of the opening and closing drive mechanism 5 and the linkage mechanism 6, until the end cover structure is tightly pressed against the side end of the filter cylinder 2, thus closing and sealing the side end of the filter cylinder 2. When the translation drive mechanism 4 drives the guide rod 23 to translate, driving the piston filter disc 22 to move towards the side end of the filter cylinder 2, the linkage end cover structure can move away from the side end of the filter cylinder 2 under the cooperation of the opening and closing drive mechanism 5 and the linkage mechanism 6, thus canceling the sealing of the side end opening of the filter cylinder 2, so that the filter residue can be discharged.
[0036] The specific principle of using this purification device to purify the primary reaction solution by pressure filtration is as follows: When the translation drive mechanism 4 drives the guide rod 23 and drives the piston filter plate 22 to move to the left to complete the left-side filter pressing action, and both the filtrate and the filter residue are discharged, the primary reaction liquid in the reactor has been introduced into the filter cylinder 2 located on the right side of the piston filter plate 22 through the feed pipe 21 to replenish the reaction liquid for the right-side filter pressing action. After that, the translation drive mechanism 4 drives the guide rod 23 and drives the piston filter plate 22 to move to the right to perform the right-side filter pressing action. When performing the right-side filter pressing action, the translation drive mechanism 4 drives the guide rod 23 and drives the piston filter press disc 22 to move to the right side of the filter press cylinder 2. First, it will work in conjunction with the left-side opening and closing drive mechanism 5 and linkage mechanism 6 to drive the left end cover structure to approach the left end of the filter press cylinder 2 until the filter plate 3 is tightly attached to the left end face of the filter press cylinder 2, thereby sealing the left end of the filter press cylinder 2. At the same time, the right end cover structure is in the closed state. As the translation drive mechanism 4 drives the piston filter press 22 to move continuously to the right, the piston filter press 22 applies pressure to the primary reaction liquid on the right side. The reaction liquid is filtered through the filter plate 3 on the right side, and the obtained clarified filtrate enters the collection space 32 and can be discharged into the regulating tank through the discharge pipe 33. Unreacted solid impurities are trapped between the filter plate 3 on the right side and the piston filter press 22, thus completing the right-side filtration. Subsequently, as the piston-type filter press 22 continues to move to the right until its limit position, the right-side opening and closing drive mechanism 5 and the linkage mechanism 6 work together to move the right-side end cover structure away from the filter press cylinder 2, thereby removing the blockage on the right-side port of the filter press cylinder 2 and allowing the filter residue after right-side filtration to be discharged. During this process, the piston-type filter press 22 is located on the right side of the feed pipe 21. Therefore, the primary reaction liquid can be fed into the filter press cylinder 2 through the feed pipe 21 to the position between the piston-type filter press 22 and the left-side end cover structure to replenish the primary reaction liquid for the next left-side filtration operation.
[0037] When the piston-type filter press 22 moves to the left to perform the left-side filter pressing action, its principle is the same as the right-side filter pressing action, except that the direction of movement is opposite. The two filter pressing actions are completed during the movement of the piston-type filter press 22 to the right and left, respectively. Under the combined action of the opening and closing drive mechanism 5 and the linkage mechanism 6, the end cap structures on both sides are alternately closed to achieve sealing and pressurization and opening for slag discharge. This timing coordination allows the piston-type filter press 22 to perform two filter pressing actions in one reciprocating cycle. The feed pipe 21 is located in the middle of the piston-type filter press 22 to replenish the primary reaction liquid for the next filter pressing process. This makes the filter pressing, liquid replenishment and slag discharge processes continuous and does not require manual cleaning, which significantly improves the continuity of operation and production efficiency.
[0038] Additionally, it is worth noting that a filter residue conveying device (not shown in the figure), such as a conveyor belt, can be installed on the base 1 at the corresponding positions below both ends of the filter cylinder 2. This device can collect the filter residue discharged from both ends of the filter cylinder 2 and transport it to the reactor so that the filter residue can participate in the reaction again. The filter residue conveying device adopts existing technology, and its specific structure and principle will not be described in detail. Example 3
[0039] Please see Figure 2 and Figure 10 Based on Embodiment 2, this embodiment provides a detailed description of the translation drive mechanism 4 in Embodiment 2, as follows: The translation drive mechanism 4 includes a guide frame 41, a first threaded rod 42, a drive motor A43, a first nut seat 44, and a traction arm 46. The guide frame 41 is fixed to the side of the side frame 11 and arranged parallel to the filter cylinder 2. The drive motor A43 is fixed to one end of the guide frame 41. The first threaded rod 42 is rotatably mounted on the guide frame 41, and one end is fixedly connected to the output shaft of the drive motor A43. The first nut seat 44 is threadedly fitted onto the first threaded rod 42. A limit rod 411 is fixed on the guide frame 41. The first nut seat 44 is slidably fitted onto the limit rod 411. A fixed seat 45 is fixed to the top of the first nut seat 44. A traction arm 46 is fixed to the side of the fixed seat 45. The other end of the traction arm 46 is fixedly connected to one end of the guide rod 23.
[0040] When the drive motor A43 drives the first threaded rod 42 to rotate, the first threaded rod 42 drives the first nut seat 44 to translate along the limit rod 411. Under the fixed connection of the fixed seat 45 and the traction arm 46, it can drive the guide rod 23 to translate axially, thereby driving the piston filter press 22 to move synchronously. Moreover, the drive motor A43 rotates in both directions, which can drive the piston filter press 22 to translate left and right respectively, providing a stable drive for the bidirectional filtration of the piston filter press 22. Example 4
[0041] Please see Figure 3 , Figure 4 , Figure 10 and Figure 11 Based on Example 3, this example provides a detailed description of the opening and closing drive mechanism 5 and the linkage mechanism 6 in Example 2, as follows: Both sides of the material collection hood 31 are fixed with side seats 301, and each side seat 301 is fixed with a first sliding rod 303. The outer wall of the filter cylinder 2 is fixed with a first sleeve 302 near both ends. The first sliding rods 303 are slidably installed in the first sleeves 302. The sliding cooperation between the first sliding rods 303 and the first sleeves 302 provides a limiting and guiding effect for the filter plate 3 and the material collection hood 31 as a whole, ensuring that the end cover structure composed of the filter plate 3 and the material collection hood 31 can only be translated along the axial direction of the filter cylinder 2, avoiding skew during the movement, and thus ensuring the sealing performance when the end cover structure is in contact with the end of the filter cylinder 2.
[0042] The opening and closing drive mechanism 5 includes a mounting base 51, a second threaded rod 52, and a second nut seat 53. The top of the material collection hoods 31 on both sides is fixed with a second nut seat 53. The mounting base 51 is fixed on both sides of the filter press cylinder 2. The second threaded rod 52 is rotatably mounted through the mounting base 51. The second nut seat 53 is threadedly fitted onto the second threaded rod 52 on the corresponding side. The linkage mechanism 6 is used to link the rotation of the second threaded rod 52 when the first nut seat 44 moves.
[0043] The linkage mechanism 6 includes a worm 62, a worm wheel 63, and a gear 64. A bracket 61 is fixed on the outer wall of the filter cylinder 2 near both ends. The worm 62 is rotatably mounted on the bracket 61. A worm wheel 63 is fixed on the ends of the two second threaded rods 52 that are close to each other. The worm wheel 63 meshes with the worm 62 on the same side. A gear 64 is fixed on one end of each of the two worms 62. An L-shaped arm 65 is fixed on the top of the fixed seat 45. A rack 66 is fixed on the end of the L-shaped arm 65. The rack 66 meshes with the two gears 64 respectively. When the filter plate 3 and the end face of the filter cylinder 2 are tightly fitted to achieve a seal, the rack 66 separates from the gear 64.
[0044] When the translation drive mechanism 4 drives the guide rod 23 and the piston filter press 22 to move from the left to the right, after completing the filter press, until the rack 66 meshes with the right gear 64, as the translation drive mechanism 4 continues to drive the guide rod 23 to move to the right, the L-shaped arm 65 drives the rack 66 to move to the right in sync. The rack 66 meshes with the drive gear 64 to rotate, which in turn drives the worm 62 to rotate. The rotating worm 62 meshes with the drive worm wheel 63 and drives the second threaded rod 52 to rotate. The rotating second threaded rod 52 drives the second nut seat 53, the filter plate 3 and the collection cover 31 to move to the right as a whole, so that the right end cover structure is away from the right end of the filter press cylinder 2, and the cover on the right port of the filter press cylinder 2 is removed so that the filter residue can be discharged. When the translation drive mechanism 4 drives the guide rod 23 and the piston filter press disc 22 to move to the left, it can synchronously drive the right rack 66 to move to the left. The right rack 66 meshes with the same side gear 64 to rotate in the opposite direction, which in turn drives the right end cover structure to move closer to the right end of the filter press cylinder 2 until the right end cover is tightly fitted with the right end face of the filter press cylinder 2. When the right end cover is sealed to the right end of the filter press cylinder 2, the right rack 66 separates from the gear 64.
[0045] When the translation drive mechanism 4 drives the guide rod 23 and the piston filter press 22 to move from right to left for filter pressing, the working principle is the same as described above. The difference is that the direction of movement is opposite, thereby realizing the linkage opening and closing of the end cover structure on both sides to facilitate the discharge of filter residue.
[0046] The unidirectional transmission between the worm 62 and the worm wheel 63 achieves a self-locking effect. After the gear 64 and the rack 66 separate, on the one hand, it prevents the second threaded rod 52 from rotating arbitrarily, causing the end cover structure to shift and resulting in sealing failure; on the other hand, it ensures that the rack 66 can accurately mesh with the gear 64 next time. Example 5
[0047] Please see Figure 7 , Figure 8 and Figure 9 The difference between this embodiment and embodiment 4 is that: A sealing ring 34 is fixed on the surfaces of the two filter plates 3 that are close to each other. When the filter plate 3 and the end face of the filter cylinder 2 are in close contact, the sealing ring 34 made of rubber material is pressed between the end face of the filter plate 3 and the end face of the filter cylinder 2, which effectively seals and prevents liquid leakage.
[0048] Furthermore, due to pressure, some solids may penetrate into the filter holes on the filter plate 3 from the direction of the filter cylinder 2 to the collection hood 31, which will cause excessive clogging over time and affect the passage of liquid during filter pressing. In order to solve the above problems, the present invention makes the following improvements: Both collection hoods 31 are equipped with air inlets 35 at their tops, and both air inlets 35 are equipped with one-way valves 36. The flow direction of the one-way valves 36 is from the outside to the inside of the collection space 32.
[0049] When the piston-type filter press 22 moves to perform filter pressing, the one-way valve 36 prevents the liquid from being discharged from the air inlet 35 due to its one-way flow guiding effect. When the end cap structure seals the side of the filter press cylinder 2 and the piston-type filter press 22 moves to the other side to perform filter pressing (the discharge valve 331 is closed), the piston-type filter press 22 fits tightly against the inner wall of the filter press cylinder 2, forming a negative pressure suction effect. External air is drawn into the collection space 32 through the air inlet 35 and finally flows into the filter press cylinder 2 through the filter holes on the filter plate 3. This reverse airflow can flush the solids accumulated in the filter holes on the filter plate 3 back into the filter press cylinder 2, achieving back-blowing cleaning of the filter holes on the filter plate 3. It can be seen that the piston-type filter press 22 serves as both a filter pressing component and a cleaning and air extraction component, achieving two goals at once. Example 6
[0050] Please see Figures 12-14 The difference between this embodiment and embodiment 5 is that: Specifically, the guide rod 23 is rotatably connected to the piston-type filter press 22, meaning that the guide rod 23 can only rotate relative to the piston-type filter press 22. The guide rod 23 is movably connected to the filter plate 3 and the collection hood 31, meaning that the guide rod 23 can both slide axially with the filter plate 3 and the collection hood 31 and rotate relative to the filter plate 3 and the collection hood 31. A scraping drive mechanism 7 is provided on the side of one side of the collection hood 31. The scraping drive mechanism 7 is used to drive the guide rod 23 to rotate. Both filter plates 3 are provided with scraping mechanisms 8. When the guide rod 23 rotates, it can drive the scraping mechanism 8 to scrape off the filter residue adhering to the filter plate 3.
[0051] Specifically, the scraping mechanism 8 includes a scraper 83, and two limiting grooves 231 are symmetrically provided on the guide rod 23. An annular sleeve 81 is rotatably installed through the center of each of the two filter plates 3. A limiting block 82 is fixed on the inner wall of the annular sleeve 81. The limiting block 82 is correspondingly limited and locked in the limiting groove 231 on the same side. A scraper 83 is fixed on the end of the two annular sleeves 81 that is close to each other. The scraper 83 is in movable contact with the surface of the filter plate 3 on the same side. The limiting block 82 is tightly fitted with the inner wall of the limiting groove 231 to prevent leakage of liquid and filter residue.
[0052] Specifically, the scraping drive mechanism 7 includes a drive motor B74, a second sleeve 71 fixed on one of the side seats 301, a second slide rod 72 slidably mounted on the second sleeve 71, a frame plate 73 fixed to one end of the second slide rod 72, the drive motor B74 fixed on the frame plate 73, and the output shaft of the drive motor B74 fixedly connected to one end of the guide rod 23. The sliding cooperation between the second sleeve 71 and the second slide rod 72 provides a limiting and guiding function for the movement of the frame plate 73 and the drive motor B74, ensuring the stability of the drive motor B74 during its movement.
[0053] When the filter cake is discharged from the end cap away from the filter cylinder 2, some filter cake will adhere to the filter plate 3 and be difficult to fall off. The drive motor B74 works, and its output shaft drives the guide rod 23 to rotate. Under the limiting action of the limiting block 82 being inserted into the limiting groove 231, the rotating guide rod 23 can drive the annular sleeve 81 and the scraper 83 to rotate synchronously. The rotating scraper 83 can scrape off the filter cake accumulated on the filter plate 3 so that the filter cake can be discharged completely.
[0054] The control method of the present invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the art. Therefore, the present invention will not explain the control method and circuit connection in detail.
[0055] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.
Claims
1. A method for purifying polyaluminum chloride, characterized in that, Specifically, the following steps are included: S1. Preparation of reaction solution: Add 100 parts by mass of industrial aluminum hydroxide to the reaction vessel, add 300-350 parts by mass of water and stir to disperse, then add 420-440 parts by mass of hydrochloric acid, pass steam to heat to 95±5℃, and react at normal pressure for 2±0.5 hours to obtain the primary reaction solution. S2, Pressure Filtration Purification: The primary reaction liquid is introduced into the purification device for pressure filtration to remove unreacted solid impurities and obtain a clear filtrate. The filter residue is returned to the reaction vessel to participate in the reaction again. S3. Adjusting basicity: Transfer the filtrate to the adjustment tank, add sodium aluminate solution, stir and react for 1-1.5 hours, and control the basicity at 40%-90% to obtain polyaluminum chloride liquid product. Among them, the purity of industrial aluminum hydroxide is ≥98%, the hydrochloric acid concentration is 30%-32%, and the aluminum oxide content in sodium aluminate solution is 10%-15%.
2. A polyaluminum chloride refining apparatus, applied to the polyaluminum chloride refining method of claim 1 above, comprising a base (1), a side frame (11) fixed above the rear side of the base (1), and a filter press (2) fixed above the base (1) by a support frame (12), characterized in that: The filter cylinder (2) is horizontally arranged and has open ends. A piston-type filter disc (22) is installed inside the filter cylinder (2), and there is a feed inlet near the middle position on the filter cylinder (2). A guide rod (23) is installed through the piston-type filter press disc (22), and both ends of the guide rod (23) extend to the outside of the filter press cylinder (2); The side frame (11) is provided with a translation drive mechanism (4) for driving the guide rod (23) to translate and adjust. The guide rod (23) is movably fitted with filter plates (3) and collection hoods (31) on both sides of the filter cylinder (2), and the filter plates (3) and collection hoods (31) on the same side form an end cap structure; The filter plate (3) is fixed to the same side collection hood (31), and a collection space (32) is formed between the two. The bottom of the collection hood (31) has a discharge port that communicates with the collection space (32). Both filter plates (3) are provided with opening and closing drive mechanisms (5), and both sides of the filter press cylinder (2) are provided with linkage mechanisms (6). The opening and closing drive mechanisms (5) and the linkage mechanisms (6) on the same side cooperate to adjust the opening and closing of the linkage end cover structure during the translation drive mechanism (4) drives the guide rod (23) to translate.
3. The polyaluminum chloride refining apparatus according to claim 2, characterized in that: The feed inlet of the filter press (2) is connected to the feed pipe (21), the end of the feed pipe (21) is connected to the discharge part of the reactor, and the feed valve (211) is installed on the feed pipe (21). The discharge ports on both sides of the material collection hood (31) are connected to discharge pipes (33), and the ends of the discharge pipes (33) are connected to the feed section of the regulating trough. Discharge valves (331) are installed on the discharge pipes (33).
4. The polyaluminum chloride refining apparatus according to claim 2, characterized in that: The translation drive mechanism (4) includes a guide frame (41), a first threaded rod (42), a drive motor A (43), a first nut seat (44), and a traction arm (46). The guide frame (41) is fixed to the side of the side frame (11) and arranged parallel to the filter cylinder (2). The drive motor A (43) is fixed to one end of the guide frame (41). The first threaded rod (42) is rotatably mounted on the guide frame (41), and one end is fixedly connected to the output shaft of the drive motor A (43); The first nut seat (44) is threadedly fitted onto the first threaded rod (42), and a limit rod (411) is fixed on the guide frame (41). The first nut seat (44) is slidably fitted onto the limit rod (411). The first nut seat (44) has a fixed seat (45) fixed on its top, and a traction arm (46) is fixed on the side of the fixed seat (45). The other end of the traction arm (46) is fixedly connected to one end of the guide rod (23).
5. The polyaluminum chloride refining apparatus according to claim 4, characterized in that: The material collection hood (31) has side seats (301) fixed on both sides, and a first slide rod (303) is fixed on each side seat (301). The filter press cylinder (2) has a first sleeve (302) fixed on its outer wall near both ends, and the first slide rod (303) is slidably installed in the first sleeve (302) in a corresponding manner. The opening and closing drive mechanism (5) includes a mounting base (51), a second threaded rod (52), and a second nut seat (53); The top of the material collection hoods (31) on both sides is fixed with the second nut seat (53); Both sides of the filter press cylinder (2) are fixed with mounting bases (51), and the second threaded rod (52) is rotatably mounted through the mounting bases (51). The second nut seat (53) is threadedly fitted onto the second threaded rod (52) on the corresponding side; The linkage mechanism (6) is used to rotate the second threaded rod (52) when the first nut seat (44) is translated.
6. The polyaluminum chloride refining apparatus according to claim 5, characterized in that: The linkage mechanism (6) includes a worm (62), a worm wheel (63), and a gear (64). The filter press cylinder (2) has brackets (61) fixed on its outer wall near both ends, and the worm gear (62) is rotatably mounted on the brackets (61). The worm gear (63) is fixed on the ends of the two second threaded rods (52) that are close to each other, and the worm gear (63) meshes with the worm (62) on the same side. The gear (64) is fixed to one end of each of the two worm gears (62); An L-shaped arm (65) is fixed to the top of the fixed base (45), and a rack (66) is fixed to the end of the L-shaped arm (65). The rack (66) meshes with the two gears (64) respectively. When the filter plate (3) and the filter cylinder (2) are tightly fitted together to achieve a seal, the rack (66) and the gear (64) are separated.
7. The polyaluminum chloride refining apparatus according to claim 2, characterized in that: A sealing ring (34) is fixed on the surfaces of the two filter plates (3) that are close to each other; Both of the material collection hoods (31) are provided with air inlets (35) at the top, and both air inlets (35) are equipped with one-way valves (36).
8. The polyaluminum chloride refining apparatus according to claim 5, characterized in that: The guide rod (23) is rotatably connected to the piston-type filter press (22); The guide rod (23) is movably connected to the filter plate (3) and the collection hood (31); A scraping drive mechanism (7) is provided on the side of the material collection hood (31) on one side, and the scraping drive mechanism (7) is used to drive the guide rod (23) to rotate; Both filter plates (3) are equipped with scraping mechanisms (8); When the guide rod (23) rotates, it can drive the scraping mechanism (8) to scrape off the filter residue adhering to the filter plate (3).
9. The polyaluminum chloride refining apparatus according to claim 8, characterized in that: The scraping mechanism (8) includes a scraper (83); The guide rod (23) is provided with two symmetrical limiting grooves (231); Both filter plates (3) are rotatably mounted with annular sleeves (81) through the center. Limiting blocks (82) are fixed on the inner edge wall of the annular sleeves (81). The limiting blocks (82) are correspondingly limited and locked in the limiting grooves (231) on the same side. The scraper (83) is fixed on one end of each of the two annular sleeves (81) that are close to each other. The scraper (83) is in contact with the surface of the filter plate (3) on the same side.
10. The polyaluminum chloride refining apparatus according to claim 8, characterized in that: The scraping drive mechanism (7) includes a drive motor B (74); A second sleeve (71) is fixed on one of the side seats (301), and a second slide rod (72) is slidably installed on the second sleeve (71). The second slide bar (72) has a frame plate (73) fixed at one end, the drive motor B (74) is fixed on the frame plate (73), and the output shaft of the drive motor B (74) is fixedly connected to one end of the guide rod (23).