Heat treatment device and treatment method for synthesizing polyaluminum chloride from aluminum trichloride wastewater

Abstract

The invention relates to the technical field of chemical wastewater treatment, in particular to a heat treatment device and a treatment method for synthesizing polyaluminum chloride from aluminum trichloride wastewater. The heat treatment device for synthesizing the polyaluminum chloride from the aluminum trichloride wastewater comprises a main body, a reaction cavity is formed in the main body, and a feeding pipe and an exhaust pipe are arranged at the top of the reaction cavity; the four-shaft stirring mechanism is arranged at the top of the main body and comprises a stirring motor, a transmission assembly and four stirring paddle groups, the stirring motor is in driving connection with the stirring paddle groups through the transmission assembly, and the stirring motor enables the adjacent stirring paddle groups to rotate in opposite directions; the heating ring sleeve is arranged outside the main body; the rotary heat exchange mechanism extends upwards from the bottom of the main body, is positioned in the center of the reaction cavity, and is embedded in the middle of the four-shaft stirring mechanism. According to the heat treatment device provided by the invention, the controllable dynamic curing effect can be achieved in the process of synthesizing aluminum trichloride wastewater into polyaluminum chloride, and the treatment effect and efficiency are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical wastewater treatment, in particular to a heat treatment device and a treatment method for synthesizing polyaluminium chloride from aluminium trichloride wastewater. Background Art

[0002] Since the production wastewater of chemical companies contains a large amount of acid, alkali or other compounds, different types of wastewater need to be transported to treatment plants with corresponding qualifications for treatment. As a result, the wastewater treatment process is not only costly, but also requires chemical companies to store the wastewater, which incurs storage costs. Moreover, untimely transportation during large-scale production may lead to limited production continuity.

[0003] Therefore, companies have begun to recycle chemical wastewater internally, recycling various elements in the wastewater or producing by-products. Aluminum chloride wastewater, a common wastewater in chemical companies, is characterized by high oil, acid, and organic matter content. The converted Al2O3 content is usually 7% to 11%. To utilize the aluminum element in aluminum chloride wastewater, some companies have begun using aluminum ash or bauxite as raw materials to neutralize aluminum chloride wastewater and then produce polyaluminum chloride.

[0004] However, if this treatment process is carried out in a static aging process, it will require a long aging time, resulting in low treatment efficiency; and if a dynamic aging process is carried out, the current wastewater treatment equipment can only perform simple heating and stirring on the aluminum chloride wastewater. It is difficult to control the stirring rate during the aging process. Too fast a stirring rate or stirring over a large range will break up the polyaluminum chloride in the flocculation, affecting the formation of polyaluminum chloride, resulting in poor aging effect, which is difficult to meet the production needs of enterprises. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a heat treatment device and a treatment method for synthesizing polyaluminium chloride from aluminium trichloride wastewater, so as to solve the problems that existing wastewater treatment equipment cannot accelerate the maturation process of aluminium trichloride wastewater, has low treatment efficiency and poor treatment effect of aluminium trichloride wastewater.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a heat treatment device for synthesizing polyaluminum chloride from aluminum trichloride wastewater, comprising: The main body has a reaction cavity inside, a feed pipe and an exhaust pipe are provided at the top of the reaction cavity, and a discharge pipe is provided at the bottom of the reaction cavity; A four-axis stirring mechanism is provided on the top of the main body and includes a stirring motor, a transmission assembly, and four stirring paddle groups. The stirring motor is connected to the stirring paddle groups through the transmission assembly, and the stirring motor causes adjacent stirring paddle groups to rotate synchronously in opposite directions. In the vertical direction, the projected area of ​​the stirring range of the blades of the stirring paddle group partially overlaps with the projected area of ​​the stirring range of the blades of the adjacent stirring paddle group. A heating ring sleeve is arranged outside the main body and is used to heat the main body; The rotating heat exchange mechanism extends upward from the bottom of the main body and is located in the center of the reaction cavity. The rotating heat exchange mechanism is embedded in the middle of the four-axis stirring mechanism. The rotating heat exchange mechanism rotates around its own axis to guide and heat the liquid in the reaction cavity. In the vertical direction, the projected area of ​​the rotating heat exchange mechanism does not overlap with the projected area of ​​the stirring range of the blades of the stirring paddle group.

[0007] In this embodiment, the transmission assembly includes a driving bevel gear, a driven bevel gear group, a first reverse conduction assembly, and a second reverse conduction assembly; the driving bevel gear is drive-connected to the output end of the stirring motor, the driven bevel gear group includes a first driven bevel gear and a second driven bevel gear, the first driven bevel gear and the second driven bevel gear are respectively engaged with both sides of the driving bevel gear, the first driven bevel gear is drive-connected to the first reverse conduction assembly, and the second driven bevel gear is drive-connected to the second reverse conduction assembly; the first reverse conduction assembly and the second reverse conduction assembly respectively drive two stirring paddle groups, and the two stirring paddle groups driven by the first reverse conduction assembly and the second reverse conduction assembly rotate in opposite directions to each other.

[0008] In this embodiment, the first reverse conduction assembly includes two sets of first conduction bevel gears and a first conduction screw. The first conduction bevel gears are arranged on both sides of the first driven bevel gear and are drivingly connected to the first conduction screw. The first conduction screw is connected to a stirring paddle group through a first conduction worm gear. The second reverse conduction assembly includes two sets of second conduction bevel gears and a second conduction screw. The second conduction bevel gears are arranged on both sides of the second driven bevel gear and are drivingly connected to the second conduction screw. The second conduction screw is drivingly connected to a stirring paddle group through a second conduction worm gear. The thread directions of the first conductive screw and the second conductive screw are opposite to each other.

[0009] In this embodiment, the stirring paddle assembly includes a stirring shaft and a plurality of stirring blade layers, and each stirring blade layer is provided with at least four stirring blades.

[0010] In this embodiment, the stirring blade portion of the stirring blade group extends into the stirring blade layer of the adjacent stirring blade group.

[0011] In this embodiment, the stirring blade layer of a stirring paddle group and the stirring blade layer of an adjacent stirring paddle group are not at the same height.

[0012] In this embodiment, the rotary heat exchange mechanism includes a rotary motor, a rotary base, and a heat exchange plate group. The output end of the rotary motor passes through the rotary base and is drivingly connected to the heat exchange plate group. The heat exchange plate group is embedded in the rotary base and rotatably connected to the rotary base. The rotating base has an annular medium output cavity and a medium input cavity from the outside to the inside. The heat-conducting medium is input into the medium input cavity or output from the medium output cavity through a conveying pipe. A medium flow channel is provided in the heat exchange plate group. The medium outlet and medium inlet of the medium flow channel are respectively connected to the annular openings of the medium output cavity and the medium input cavity.

[0013] In this embodiment, the heat exchange plate group includes a rotating base and four heat spreaders that intersect in a cross shape as a whole. Four groups of medium flow channels are provided corresponding to the heat spreaders. Each group of medium flow channels extends upward from the outer bottom of the rotating base and reciprocates horizontally. After extending to the top of the medium flow channel, the medium flow channel extends horizontally to the center of the heat spreader, and extends vertically downward from the center of the heat spreader to the bottom of the rotating base.

[0014] In this embodiment, the heat spreader is provided with a circulation through hole, and the circulation through hole is arranged away from the medium flow channel.

[0015] The present invention also provides a heat treatment method for synthesizing polyaluminium chloride from aluminium trichloride wastewater, which adopts any of the above-described heat treatment devices for synthesizing polyaluminium chloride from aluminium trichloride wastewater, and the steps are as follows: S1. After simple filtration, the wastewater to be treated is input into a heat treatment device for synthesizing polyaluminium chloride from aluminium trichloride wastewater. The four-axis stirring mechanism is turned on and the wastewater to be treated is heated to 50°C to 60°C through a heating ring and a rotary heat exchange mechanism. S2. The four-axis stirring mechanism and the rotary heat exchange mechanism enter a high-speed stirring state, and calcium aluminate powder is added. The mass ratio of the wastewater to be treated to the calcium aluminate powder is 9 to 12:1. The high-speed stirring state is continued for 25 to 40 minutes at a high-speed stirring rate of 100 to 300 rpm. S3. After the stirring is completed, the heating ring and the rotary heat exchange mechanism heat the mixed wastewater at 90°C to 95°C for 2 to 3 hours; during the aging process, the rotary heat exchange mechanism continuously enters a low-speed stirring state with a rotation rate of 15 to 50 rpm, and the four-axis stirring mechanism stirs at a low speed for 5 minutes every 25 minutes, and the ratio of the rotation rate of the four-axis stirring mechanism to the rotation rate of the rotary heat exchange mechanism is 0.2 to 1:1; S4. After the aging is completed, the reaction mixture is output from the heat treatment device for synthesizing polyaluminum chloride from aluminum trichloride wastewater and filtered to obtain the target PAC (polyaluminum chloride solution) product.

[0016] The beneficial effects of the present invention are: In the current aluminum chloride wastewater treatment process, aluminum ash or bauxite is usually used as a neutralizing material, which is added to the aluminum chloride wastewater for a static aging reaction to obtain polyaluminum chloride. However, the static aging process requires a long aging time, which not only has low treatment efficiency, but also because the aluminum chloride wastewater contains organic impurities and has a high overall viscosity, and conventional treatment equipment is difficult to fully mix the aluminum chloride wastewater with aluminum ash or bauxite, which may cause uneven distribution of the aluminum ash or bauxite. After the aluminum ash or bauxite is replaced with calcium aluminate powder, the uneven distribution phenomenon may further lead to excessive local temperature fluctuations, causing some polyaluminum chloride to decompose, affecting the treatment efficiency and treatment effect of the aluminum chloride wastewater, resulting in insufficient wastewater treatment effect of the final polyaluminum chloride product.

[0017] Therefore, the present invention sets a four-axis stirring mechanism in the reaction cavity, adopts a drive motor to drive four groups of stirring paddle groups, realizes the synchronous rotation of the four groups of stirring paddle groups through the transmission assembly, and the adjacent stirring paddle groups rotate in opposite directions, so that the liquid in the reaction cavity forms turbulence as a whole, effectively eliminates the stirring dead angle at the edge of the reaction cavity, and prevents the occurrence of laminar flow and the agglomeration of calcium aluminate powder, thereby making the aluminum chloride wastewater and calcium aluminate powder fully mixed, ensuring the treatment effect. In addition, the turbulent state enables the liquid in the reaction cavity to better exchange heat and ensure the accuracy of temperature control.

[0018] If only a four-axis stirring mechanism is used, during the stirring process, the rotation of the four groups of stirring paddles causes the liquid to collide and intersect at the center of the four-axis stirring mechanism, which may form a vortex, causing calcium aluminate powder to accumulate in the center, or making it difficult for the liquid in the center to flow to the outside of the reaction cavity, resulting in a central dead zone in the overall flow of the reaction liquid, affecting the mixing and temperature control effects. At the same time, during the aging process, the excessive stirring effect of the four-axis stirring mechanism will break up the molecular chains of polyaluminum chloride. Even at low speeds, the four groups of stirring paddles cause the reaction liquid to intersect and collide from the edges when flowing to the center area, resulting in excessive agglomeration. Not only will the dynamic aging effect fail to be achieved, but the quality of the final product will also be affected.

[0019] Therefore, the present invention sets a rotary heat exchange mechanism in the center of the reaction cavity, and the rotary heat exchange mechanism extends upward from the bottom of the main body into the middle of the four-axis stirring mechanism, that is, the rotary heat exchange mechanism is set in the dead corner of the stirring area of ​​the four groups of stirring paddle groups. Through the self-rotation of the rotary heat exchange mechanism, the liquid in the central area is guided to the outside of the reaction cavity by centrifugal force, which not only eliminates the vortex that may appear in the central position, but also can rotate at a low speed when entering the aging process, forming a laminar flow as a whole, so that the liquid in the reaction cavity can be prevented from being broken up while flowing slowly, thereby improving the aging efficiency and lengthening the molecular chain of the finally obtained polyaluminum chloride.

[0020] In addition, the rotary heat exchange mechanism can cooperate with the heating jacket to heat the reaction liquid simultaneously from the center and periphery of the reaction cavity, thereby accelerating the heat conduction rate, which not only ensures the uniformity and accuracy of heating, but also effectively reduces energy costs.

[0021] Moreover, the processing method of synthesizing polyaluminium chloride from aluminium chloride wastewater provided by the present invention, after preliminary filtration of aluminium chloride wastewater, is passed into the heat treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater, and aluminium chloride wastewater and calcium aluminate powder are fully stirred at a set temperature by a four-axis stirring mechanism in conjunction with a rotary heat exchange mechanism, and after entering the slaking stage, the reaction solution is guided to rotate slowly as a whole by a rotary heat exchange mechanism capable of rotating and heating, forming a laminar flow, accelerating the generation of polyaluminium chloride and extending the molecular weight of polyaluminium chloride, and then the reaction solution is slowly mixed as a whole within a set time by an intermittently rotating four-axis stirring mechanism, avoiding side sedimentation and agglomeration. At the same time, the four-axis stirring mechanism causes the reaction solution to be led to the central area by the side of the reaction cavity and fully exchange heat with the four-axis stirring mechanism, ensuring that the temperature control in the reaction cavity is accurate and sensitive, and uniform and stable, not only having high processing efficiency, but also significantly reducing the slaking time, and ensuring that the obtained polyaluminium chloride solution has a high effective component content, and has a good sewage treatment effect.

[0022] Other features and beneficial effects of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other beneficial effects of the present invention can be achieved and obtained by the structures and / or components specified in the description and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a three-dimensional schematic diagram of an embodiment of the present invention; Figure 2 for Figure 1 A top view of Figure 3 for Figure 2 Cross-section at AA; Figure 4 for Figure 3 A partial enlarged view of point B in the middle; Figure 5 for Figure 3 A partial enlarged view of point E in the middle; Figure 6 This is a three-dimensional schematic diagram of a four-axis stirring mechanism in one embodiment of the present invention; Figure 7 for Figure 6 A partial enlarged view of point D in the middle; Figure 8 for Figure 6 A top view of Figure 9A three-dimensional schematic diagram of a rotary heat exchange mechanism in one embodiment of the present invention; Figure 10 This is an exploded view of a rotary heat exchange mechanism according to an embodiment of the present invention; Figure 11 for Figure 10 The main view; Figure 12 for Figure 11 Cross-section at CC; Figure 13 FIG. 1 is a perspective schematic diagram of a rotating base in one embodiment of the present invention.

[0024] Description of labels: 1. Main body; 11. Reaction cavity; 12. Feed pipe; 13. Exhaust pipe; 14. Discharge pipe; 15. Rubber layer; 2. Four-axis stirring mechanism; 21. Stirring motor; 22. Transmission assembly; 221. Active bevel gear; 222. Driven bevel gear group; 2221. First driven bevel gear; 2222. Second driven bevel gear; 223. First reverse conduction assembly; 2231. First conduction bevel gear; 2232. First conduction screw; 2233. First conduction worm gear; 224. Second reverse conduction assembly; 2241. Second conduction bevel gear; 2242. Second conduction screw; 2243, second conduction worm gear; 23, stirring paddle group; 231, stirring shaft; 232, stirring blade layer; 24, protective shell; 241, connecting bolt; 242, extension part; 243, interlocking protrusion; 244, sealing ring plate; 3, heating ring sleeve; 4, rotating heat exchange mechanism; 41, rotating motor; 42, rotating base; 421, medium output cavity; 422, medium input cavity; 423, delivery pipe; 424, annular opening; 43, heat exchange plate group; 431, rotating base; 432, heat spreader; 433, medium flow channel. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments; the technical features designed in different implementation modes of the present invention described below can be combined with each other as long as they do not conflict with each other; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meanings as those generally understood by ordinary technicians in the field to which the present invention belongs, and should not be understood as limiting the present invention; it should be further understood that the terms used in the present invention should be understood to have the same meanings as these terms in the context of this specification and the relevant field, and should not be understood in an idealized or overly formal sense, unless explicitly defined as such in the present invention.

[0027] To illustrate the technical content, achieved objectives and effects of the present invention in detail, the following description is given in conjunction with the embodiments and accompanying drawings.

[0028] Please refer to Figures 1 to 12 A heat treatment device for synthesizing polyaluminium chloride from aluminium trichloride wastewater, comprising: The main body 1 has a reaction cavity 11 inside. A feed pipe 12 and an exhaust pipe 13 are provided at the top of the reaction cavity 11, and a discharge pipe 14 is provided at the bottom of the reaction cavity 11. The four-axis stirring mechanism 2 is arranged on the top of the main body 1 and includes a stirring motor 21, a transmission assembly 22 and four stirring paddle groups 23. The stirring motor 21 is driven and connected to the stirring paddle groups 23 through the transmission assembly 22. The stirring motor 21 causes adjacent stirring paddle groups 23 to rotate synchronously in opposite directions. In the vertical direction, the projected area of ​​the stirring range of the blades of the stirring paddle group 23 partially overlaps with the projected area of ​​the stirring range of the blades of the adjacent stirring paddle group 23. The heating ring 3 is arranged outside the main body 1 and is used to heat the main body 1.

[0029] The rotating heat exchange mechanism 4 extends upward from the bottom of the main body 1 and is located in the center of the reaction cavity 11. The rotating heat exchange mechanism 4 is embedded in the middle of the four-axis stirring mechanism 2. The rotating heat exchange mechanism 4 rotates around its own axis to guide and heat the liquid in the reaction cavity 11; in the vertical direction, the projected area of ​​the rotating heat exchange mechanism 4 does not overlap with the projected area of ​​the stirring range of the blades of the stirring paddle group 23.

[0030] Specifically, in the vertical direction, the axes of the four stirring paddle groups 23 are distributed in a rectangular shape as a whole, and the stirring ranges of the four stirring paddle groups 23 partially overlap with each other. Moreover, since the adjacent stirring paddle groups 23 rotate synchronously in opposite directions, the stirring paddle groups 23 in the overlapping areas will not interfere with the operation of other stirring paddle groups 23, thereby ensuring the stirring effect while avoiding damage to the four-axis stirring mechanism 2.

[0031] Specifically, the rotary heat exchange mechanism 4 is disposed at the intersection center of the four stirring paddle groups 23 and does not touch the stirring paddle groups 23 , further ensuring that the four-axis stirring mechanism 2 and the rotary heat exchange mechanism 4 can operate normally.

[0032] Specifically, the heating ring 3 is provided with a heating medium inlet pipe and a heating medium outlet pipe. Those skilled in the art can adjust the temperature of the heating ring 3 by inputting heating media of different temperatures, thereby adjusting the temperature of the liquid in the reaction cavity 11. Furthermore, an electric heating pipe is provided inside the heating ring 3.

[0033] Since there are overlapping stirring areas between the stirring paddle groups 23 , in order to ensure that the stirring paddle groups 23 do not collide during rotation, the transmission assembly 22 needs to keep the rotation speed of each stirring paddle group 23 consistent. Therefore, in this embodiment, the transmission assembly 22 includes a driving bevel gear 221, a driven bevel gear group 222, a first reverse conduction assembly 223, and a second reverse conduction assembly 224; the driving bevel gear 221 is drivingly connected to the output end of the stirring motor 21, and the driven bevel gear group 222 includes a first driven bevel gear 2221 and a second driven bevel gear 2222, which are respectively engaged with both sides of the driving bevel gear 221, the first driven bevel gear 2221 is drivingly connected to the first reverse conduction assembly 223, and the second driven bevel gear 2222 is drivingly connected to the second reverse conduction assembly 224; the first reverse conduction assembly 223 and the second reverse conduction assembly 224 respectively drive two stirring paddle groups 23, and the two stirring paddle groups 23 driven by the first reverse conduction assembly 223 and the second reverse conduction assembly 224 rotate in opposite directions. With this arrangement, the first and second driven bevel teeth 2221 and 2222 meshing on either side of the driving bevel teeth 221 cause the first and second reverse transmission components 223 and 224 to rotate in opposite directions. The first and second reverse transmission components 223 and 224 can further drive the agitator assembly 23 using a worm gear and worm combination or gear set with the same transmission ratio, ensuring synchronous reverse rotation.

[0034] To ensure sufficient stirring space between the four stirring paddle groups 23 and prevent the stirring paddle groups 23 from contacting the axes of other stirring paddle groups 23 during rotation, the first reverse conduction component 223 includes two sets of first conduction bevel teeth 2231 and a first conduction screw 2232. The first conduction bevel teeth 2231 are arranged on both sides of the first driven bevel teeth 2221 and are drivingly connected to the first conduction screw 2232. The first conduction screw 2232 is drivingly connected to one stirring paddle group 23 through a first conduction worm gear 2233. The second reverse conduction assembly 224 includes two sets of second conduction bevel gears 2241 and a second conduction screw 2242. The second conduction bevel gears 2241 are arranged on both sides of the second driven bevel gear 2222 and are drivingly connected to the second conduction screw 2242. The second conduction screw 2242 is drivingly connected to a stirring paddle assembly 23 via a second conduction worm gear 2243. The thread directions of the first conduction screw 2232 and the second conduction screw 2242 are opposite.

[0035] Specifically, transmission bevel teeth are provided on the backs of the first driven bevel gear 2221 and the second driven bevel gear 2222 , and the first conductive bevel gear 2231 and the second conductive bevel gear 2241 are respectively engaged with the transmission bevel teeth on the backs of the first driven bevel gear 2221 or the second driven bevel gear 2222 .

[0036] Specifically, the first conduction screw 2232 can be a right-handed screw, and the second conduction screw 2242 can be a left-handed screw. The first conduction worm gear 2233 and the second conduction worm gear 2243 are arranged corresponding to the first conduction screw 2232 and the second conduction screw 2242.

[0037] To ensure that the reaction liquid in the reaction cavity 11 can be fully stirred from top to bottom, in this embodiment, the stirring paddle group 23 includes a stirring shaft 231 and a plurality of stirring blade layers 232 , and each stirring blade layer 232 is provided with at least four stirring blades.

[0038] Preferably, each stirring blade layer 232 is provided with six stirring blades, and each stirring blade group 23 is provided with six to eight stirring blade layers 232. Furthermore, the liquid in the reaction cavity 11 can circulate from bottom to top or from top to bottom under the action of the stirring blade groups 23 with different rotation directions. Specifically, those skilled in the art can adjust the angles of the stirring blades at different positions in each stirring blade layer 232 as needed, without specific limitation.

[0039] In this embodiment, the stirring blades of the stirring paddle group 23 partially extend into the stirring blade layer 232 of the adjacent stirring paddle group 23. Preferably, the angle between the stirring blades and the stirring blades of other adjacent stirring paddle groups 23 is 15° to 60°.

[0040] In order to further ensure that the four-axis stirring mechanism 2 does not hit each other and cause damage during stirring, in this embodiment, the stirring blade layer 232 of the stirring paddle group 23 and the stirring blade layer 232 of the adjacent stirring paddle group 23 are not at the same height. In addition, this arrangement can further avoid excessive collision of the reaction liquid at the center position during the intermittent rotation of the four-axis stirring mechanism 2 when entering the maturation stage, reduce the fragmentation of polyaluminum chloride, extend the molecular chain of polyaluminum chloride, and thus improve the flocculation and purification effect of the product.

[0041] To prevent external dust, moisture, and other substances from affecting the operation of the transmission assembly, in this embodiment, the four-axis stirring mechanism 2 also includes a protective housing 24. The protective housing 24 is disposed on the top of the main body 1. The protective housing 24 and the main body 1 form a protective cavity. The transmission assembly 22 is disposed within the protective cavity. The stirring motor 21 is disposed on the top of the protective housing 24. The output end of the protective housing 24 extends through the protective housing 24 into the protective cavity and is drivingly connected to the transmission assembly 22. The protective housing 24 is fixedly connected to the top of the main body 1 by connecting bolts 241.

[0042] Since the stirring motor 21 is arranged at the top of the protective shell 24, the stirring motor 21 needs to drive the transmission assembly 22 and the four stirring paddle groups. The required power is relatively large, resulting in a large overall weight of the stirring motor 21, making the entire four-axis stirring mechanism 2 top-heavy. During operation, the stirring motor 21 may cause a slight shift in the center of gravity after the action, causing the protective shell 24 to be subjected to forces tilted in different directions, resulting in excessive axial force on the local connecting bolts 241, causing the connecting bolts 241 to loosen after long-term use. An extension portion 242 extending along the top outer surface of the main body 1 is provided at the bottom of the protective shell 24, and the connecting bolts 241 are provided on the extension portion 242. After installation, the extension portion 242 abuts against the top of the main body 1, greatly increasing the support surface and contact surface between the protective shell 24 and the main body 1, thereby evenly transmitting the force of the stirring motor 21 to the main body 1, thereby improving the overall service life.

[0043] After the protective shell 24 is set, the reaction force of the torque received by the stirring motor 21 when driving the transmission assembly 22 will be directly transmitted to the protective shell 24, causing the connecting bolt 241 to be subjected to a lateral shear force. In the aging stage, the stirring motor 21 needs to be started intermittently. The frequent starting brings about an instantaneous shear force, which increases the load of the connecting bolt 241. Long-term use may cause the connecting bolt 241 to break, causing the protective shell 24 to twist, thereby causing the stirring motor 21 and the transmission assembly 22 to be misaligned. Therefore, a plurality of interlocking protrusions 243 are provided at intervals below the extension 242. The main body 1 is provided with an opening corresponding to the interlocking protrusion 243. The inner surface of the opening is provided with a rubber layer 15. The interlocking protrusion 243 passes through the opening and enters the reaction cavity 11. At the same time, a sealing ring plate 244 is provided at the top of the reaction cavity 11 corresponding to the extension 242. The interlocking protrusion 243 is fixedly connected to the sealing ring plate 244. After the sealing ring plate 244 is provided, it is not only possible to avoid the liquid in the reaction cavity 11 from corroding the interlocking protrusion 243.

[0044] Specifically, the sealing ring plate 244 is welded to the interlocking protrusion 243 and the top of the reaction chamber 11, thereby ensuring the airtightness of the reaction chamber 11. The sealing ring plate 244, the connecting bolts 241, and the connecting structure of the extension 242 cooperate to form a clamping structure between the protective housing 24 and the main body 1. The protective housing 24 is fixed and supported on both the upper and lower sides of the main body 1, further ensuring the stability and safety of the connection of the entire device and effectively preventing the stirring motor 21 from deviating and causing damage to the device.

[0045] The rotating heat exchange mechanism 4 needs to perform heat exchange while being able to rotate itself. To ensure that the heat exchange process can adapt to the rotation process, in this embodiment, the rotating heat exchange mechanism 4 includes a rotating motor 41, a rotating base 42, and a heat exchange plate group 43. The output end of the rotating motor 41 passes through the rotating base 42 and is drivingly connected to the heat exchange plate group 43. The heat exchange plate group 43 is embedded in the rotating base 42 and is rotatably connected to the rotating base 42. The rotating base 42 has an annular medium output chamber 421 and a medium input chamber 422 from the outside to the inside. The heat-conducting medium is input into the medium input chamber 422 or output from the medium output chamber 421 through a delivery pipe 423. A medium flow channel 433 is provided in the heat exchange plate group 43. The medium outlet and medium inlet of the medium flow channel 433 are respectively connected to the annular openings 424 of the medium output chamber 421 and the medium input chamber 422. Specifically, because the heat exchange plate group 43 is a vertical plate-like structure, when the heat exchange plate group 43 rotates, it can disturb the reaction liquid in the reaction cavity 11 to a large extent compared to the stirring paddle. At the same time, the plate-like structure has a small shearing effect on the reaction liquid, which can effectively prevent the rotation during the aging process from interrupting the molecular chains of the polyaluminum chloride, thereby improving the quality of the produced polyaluminum chloride while ensuring dynamic stirring.

[0046] In this embodiment, the heat exchange plate group 43 includes a rotating base 431 and four heat spreaders 432 that intersect in a cross shape. Four groups of medium flow channels 433 are provided corresponding to the heat spreaders 432. Each group of medium flow channels 433 extends upward and reciprocatingly in the horizontal direction from the outer bottom of the rotating base 431. After extending to the top of the medium flow channel 433, the medium flow channel 433 extends horizontally to the center of the heat spreader 432, and extends vertically downward from the center of the heat spreader 432 to the bottom of the rotating base 431.

[0047] Preferably, vapor chamber 432 is provided with flow holes (not shown), which are arranged away from medium flow channel 433. The provision of these flow holes can reduce the blockage of the reaction liquid during low-speed rotation in a portion of vapor chamber 432. The reaction liquid in the corresponding region can pass through vapor chamber 432 via the flow holes, creating a flow velocity difference in the local area, thereby forming a localized laminar flow and further enhancing the pulling effect on the polyaluminum chloride. Furthermore, the provision of these flow holes can increase the heat exchange area, improving the heat exchange rate and heat exchange effect.

[0048] The present invention also provides a heat treatment method for synthesizing polyaluminium chloride from aluminium trichloride wastewater, which adopts any of the above-described heat treatment devices for synthesizing polyaluminium chloride from aluminium trichloride wastewater, and the steps are as follows: S1, after simply filtering the wastewater to be treated, input it into the heat treatment device for synthesizing polyaluminium chloride from aluminium trichloride wastewater, turn on the four-axis stirring mechanism 2 and heat the wastewater to be treated to 50°C to 60°C through the heating ring 3 and the rotary heat exchange mechanism 4; S2, the four-axis stirring mechanism 2 and the rotary heat exchange mechanism 4 enter a high-speed stirring state, calcium aluminate powder is added, the mass ratio of the wastewater to be treated to the calcium aluminate powder is 9-12:1, the high-speed stirring state is continued for 25-40 minutes, and the high-speed stirring rate is 100-300 rpm; S3. After the stirring is completed, the heating ring 3 and the rotary heat exchange mechanism 4 heat the mixed wastewater at 90°C to 95°C for 2 to 3 hours; during the aging process, the rotary heat exchange mechanism 4 continuously enters a low-speed stirring state with a rotation rate of 15 to 50 rpm, and the four-axis stirring mechanism 2 stirs at a low speed for 5 minutes every 25 minutes, and the ratio of the rotation rate of the four-axis stirring mechanism 2 to the rotation rate of the rotary heat exchange mechanism 4 is 0.2 to 1:1; S4. After the aging is completed, the reaction mixture is output from the heat treatment device for synthesizing polyaluminum chloride from aluminum chloride wastewater and filtered to obtain the target PAC product.

[0049] Example 1 Raw materials: aluminum chloride wastewater (Al2O3 content 7.5%, acidity 6%), calcium aluminate powder (industrial grade).

[0050] Processing steps: S1. After simple filtration, the wastewater to be treated is fed into a heat treatment device for synthesizing polyaluminium chloride from aluminium trichloride wastewater. The four-axis stirring mechanism 2 is turned on and the wastewater to be treated is heated to 55±2°C through the heating ring 3 and the rotary heat exchange mechanism 4. S2, the four-axis stirring mechanism 2 and the rotary heat exchange mechanism 4 enter a high-speed stirring state, and calcium aluminate powder is added. The mass ratio of the wastewater to be treated to the calcium aluminate powder is 10:1. The high-speed stirring state is continued for 30 minutes at a high-speed stirring rate of 200 rpm; S3. After the stirring is completed, the heating ring 3 and the rotary heat exchange mechanism 4 heat the mixed wastewater at 92±1°C for aging for 2 hours. During the aging process, the rotary heat exchange mechanism 4 continuously enters a low-speed stirring state with a rotation rate of 20 rpm, and the four-axis stirring mechanism 2 stirs at a low speed of 10 rpm for 5 minutes every 25 minutes. S4. After the aging is completed, the reaction mixture is discharged from the heat treatment device for synthesizing polyaluminium chloride from aluminium trichloride wastewater and filtered to obtain the target PAC product (Al2O3 content 9.8%).

[0051] The prepared PAC product was subjected to sewage treatment experiments: Wastewater properties: turbidity 238 NTU, COD 14670 mg / L, suspended solids 267 mg / L, pH 4. PAC dosage: 1 L / ton of raw water. The treatment results are shown in Table 1.

[0052] Table 1 Sewage treatment results

[0053] Example 2 Raw material: aluminum chloride wastewater (Al2O3 content 8%, acidity 5%).

[0054] Processing steps: Same as Example 1, except that the aging temperature was adjusted to 95±1°C, the aging time was 3 hours, the high-speed stirring rate of the four-axis stirring mechanism and the rotary heat exchange mechanism was 260 rpm, the low-speed stirring rate of the rotary heat exchange mechanism was 25 rpm, and the low-speed stirring rate of the four-axis stirring mechanism was 20. Finally, a PAC product (Al2O3 content: 10.5%) was obtained.

[0055] The prepared PAC product was subjected to sewage treatment experiments: Sewage properties: turbidity 369 NTU, COD 17640 mg / L, suspended solids 423 mg / L, pH 3, PAC dosage: 1.5 L / ton of raw water. The treatment effect is shown in Table 2.

[0056] Table 2 Treatment effects

[0057] In addition, those skilled in the art should understand that, although there are many problems in the prior art, each embodiment or technical solution of the present invention may be improved in only one or several aspects, without having to simultaneously solve all the technical problems listed in the prior art or background art. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as limiting the claim.

[0058] Although terms such as "body" and "reaction cavity" are frequently used herein, the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations is contrary to the spirit of the present invention. The terms "first" and "second" (if any) in the description and claims of the embodiments of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater, characterized in that: include: A main body (1) has a reaction cavity (11) therein, a feed pipe (12) and an exhaust pipe (13) are provided at the top of the reaction cavity (11), and a discharge pipe (14) is provided at the bottom of the reaction cavity (11); A four-axis stirring mechanism (2) is arranged on the top of the main body (1), comprising a stirring motor (21), a transmission assembly (22) and four stirring paddle groups (23), wherein the stirring motor (21) is connected to the stirring paddle groups (23) through the transmission assembly (22), and the stirring motor (21) causes adjacent stirring paddle groups (23) to rotate synchronously in opposite directions; in the vertical direction, the projected area of ​​the stirring range of the blades of the stirring paddle groups (23) partially overlaps with the projected area of ​​the stirring range of the blades of the adjacent stirring paddle groups (23); A heating ring (3) is arranged outside the main body (1) and is used to heat the main body (1); A rotating heat exchange mechanism (4) extends upward from the bottom of the main body (1) and is located in the center of the reaction cavity (11). The rotating heat exchange mechanism (4) is embedded in the middle of the four-axis stirring mechanism (2). The rotating heat exchange mechanism (4) rotates around its own axis to guide and heat the liquid in the reaction cavity (11); in the vertical direction, the projected area of ​​the rotating heat exchange mechanism (4) does not overlap with the projected area of ​​the stirring range of the blades of the stirring paddle group (23).

2. The thermal treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater according to claim 1, wherein: The transmission assembly (22) comprises an active bevel gear (221), a driven bevel gear group (222), a first reverse transmission assembly (223) and a second reverse transmission assembly (224); the active bevel gear (221) is drivingly connected to the output end of the stirring motor (21); the driven bevel gear group (222) comprises a first driven bevel gear (2221) and a second driven bevel gear (2222); the first driven bevel gear (2221) and the second driven bevel gear (2222) are respectively engaged with the active bevel gear (221) and the second driven bevel gear (2222) ), the first driven bevel gear (2221) is drivingly connected to the first reverse conduction component (223), and the second driven bevel gear (2222) is drivingly connected to the second reverse conduction component (224); the first reverse conduction component (223) and the second reverse conduction component (224) respectively drive the two stirring paddle groups (23), and the two stirring paddle groups (23) driven by the first reverse conduction component (223) and the second reverse conduction component (224) rotate in opposite directions.

3. The thermal treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater according to claim 2, wherein: The first reverse conduction component (223) comprises two groups of first conduction bevel teeth (2231) and a first conduction screw (2232), wherein the first conduction bevel teeth (2231) are arranged on both sides of the first driven bevel teeth (2221) and are drivingly connected to the first conduction screw (2232), and the first conduction screw (2232) is drivingly connected to one of the stirring paddle groups (23) via a first conduction worm gear (2233); The second reverse conduction component (224) comprises two groups of second conduction bevel teeth (2241) and a second conduction screw (2242), wherein the second conduction bevel teeth (2241) are arranged on both sides of the second driven bevel teeth (2222) and are drivingly connected to the second conduction screw (2242), and the second conduction screw (2242) is drivingly connected to one of the stirring paddle groups (23) via a second conduction worm gear (2243); The thread directions of the first conduction screw (2232) and the second conduction screw (2242) are opposite.

4. The thermal treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater according to claim 1, wherein: The stirring paddle group (23) comprises a stirring shaft (231) and a plurality of stirring blade layers (232), and each stirring blade layer (232) is provided with at least four stirring blades.

5. The thermal treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater according to claim 4, wherein: The stirring blade portion of the stirring blade group (23) extends into the stirring blade layer (232) of the adjacent stirring blade group (23).

6. The thermal treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater according to claim 4, characterized in that: The stirring blade layer (232) of the stirring blade group (23) and the stirring blade layer (232) of the adjacent stirring blade group (23) are not at the same height.

7. The thermal treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater according to claim 1, characterized in that: The rotary heat exchange mechanism (4) comprises a rotary motor (41), a rotary base (42) and a heat exchange plate group (43); the output end of the rotary motor (41) passes through the rotary base (42) and is drivingly connected to the heat exchange plate group (43); the heat exchange plate group (43) is embedded in the rotary base (42) and is rotatably connected to the rotary base (42); The rotating base (42) has an annular medium output cavity (421) and a medium input cavity (422) from the outside to the inside, and the heat-conducting medium is input into the medium input cavity (422) or output from the medium output cavity (421) through a delivery pipe (423); a medium flow channel (433) is provided in the heat exchange plate group (43), and the medium outlet and the medium inlet of the medium flow channel (433) are respectively connected to the annular openings (424) of the medium output cavity (421) and the medium input cavity (422).

8. The thermal treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater according to claim 7, characterized in that: The heat exchange plate group (43) includes a rotating base (431) and four heat spreaders (432) that intersect in a cross shape. Four groups of medium flow channels (433) are provided corresponding to the heat spreaders (432). Each group of medium flow channels (433) extends upward and reciprocatingly in the horizontal direction from the outer bottom of the rotating base (431). After extending to the top of the medium flow channel (433), the medium flow channel (433) extends horizontally to the center of the heat spreader (432), and extends vertically downward from the center of the heat spreader (432) to the bottom of the rotating base (431).

9. The thermal treatment device for synthesizing polyaluminium chloride from aluminium chloride wastewater according to claim 8, characterized in that: The heat spreader (432) is provided with a circulation through hole, and the circulation through hole is arranged to avoid the medium flow channel (433).

10. A method for synthesizing polyaluminium chloride from aluminium trichloride wastewater, characterized in that: The heat treatment device for synthesizing polyaluminium chloride from aluminium trichloride wastewater as claimed in any one of claims 1 to 9 is used, and the steps are as follows: S1, after simply filtering the wastewater to be treated, input it into the heat treatment device for synthesizing polyaluminium chloride from aluminium trichloride wastewater, turn on the four-axis stirring mechanism (2), and heat the wastewater to be treated to 50°C to 60°C through the heating ring (3) and the rotary heat exchange mechanism (4); S2, the four-axis stirring mechanism (2) and the rotary heat exchange mechanism (4) enter a high-speed stirring state, calcium aluminate powder is added, the mass ratio of the wastewater to be treated to the calcium aluminate powder is 9 to 12:1, the high-speed stirring state is continued for 25 to 40 minutes, and the high-speed stirring rate is 100 to 300 rpm; S3. After the stirring is completed, the heating ring (3) and the rotary heat exchange mechanism (4) heat the mixed wastewater at 90°C to 95°C and mature for 2 to 3 hours; during the maturation process, the rotary heat exchange mechanism (4) continuously enters a low-speed stirring state with a rotation rate of 15 to 50 rpm, and the four-axis stirring mechanism (2) stirs at a low speed for 5 minutes every 25 minutes, and the ratio of the rotation rate of the four-axis stirring mechanism (2) to the rotation rate of the rotary heat exchange mechanism (4) is 0.2 to 1:1; S4. After the aging is completed, the reaction mixture is output from the heat treatment device for synthesizing polyaluminum chloride from aluminum trichloride wastewater and filtered to obtain the target polyaluminum chloride solution.

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