Device and process for improving alkalization degree of polyaluminum chloride and content of solid aluminum oxide

Abstract

The invention discloses a device and a process for improving the alkalization degree of polyaluminum chloride and the content of solid aluminum oxide, and relates to the technical field of chemical equipment, a mounting cylinder, a dispersion mechanism and a plurality of ion exchange mechanisms are arranged, so that multi-stage and alternate ion exchange and forced redispersion treatment of a high-viscosity polyaluminum chloride salt raw solution are realized, and the high-viscosity polyaluminum chloride salt is obtained. The phenomena of dead zone, bias flow and channeling caused by high viscosity characteristic in the traditional single-stage or simple multi-stage fixed bed are effectively inhibited, the flow field of the solution in each ion exchange layer tends to be uniform, and the actual effective contact time is closer to the theoretical retention time, so that the chloride ion removal rate and the alkalization degree amplification are obviously improved, and the quality of the product is improved. Meanwhile, the stability of the content of solid aluminum oxide and the quality consistency between batches of products are improved, and finally the overall quality stability and preparation efficiency of the polyaluminum chloride salt product are improved.

Description

Technical Field

[0001] This invention relates to the field of chemical equipment technology, and in particular to a device and process for increasing the basicity of polyaluminum chloride and the content of solid alumina. Background Technology

[0002] With the continuous advancement of chemical separation and purification technologies, the application of anion exchange resins in the preparation of inorganic polymer flocculants has been gradually deepened. Initially, polyaluminum chloride (PAC) was mainly prepared through the traditional acid-solution-alkali polymerization process, which suffered from difficulties in controlling alkalinity, poor product stability, and numerous byproducts. To address these issues, researchers gradually introduced ion exchange methods, utilizing anion exchange columns to selectively remove or replace chloride ions or other anions in the solution. This allows for precise control of the hydroxyl to aluminum ratio (alkalinity) in the polyaluminum chloride solution, improving the stability and flocculation performance of polyaluminum chloride salt products.

[0003] In existing technologies, pre-prepared high-viscosity polyaluminum chloride (PAC) liquid is typically used as the feed solution and pumped from top to bottom (or bottom to top) into an exchange column packed with strongly or weakly basic anion exchange resin. The functional groups on the resin (such as quaternary ammonium groups or tertiary amine groups) undergo ion exchange reactions with chloride ions or other exchangeable anions in the PAC solution, thereby reducing the free chloride ion content in the solution and simultaneously increasing the basicity, ultimately yielding a polyaluminum chloride salt product with the target basicity. To ensure the continuity and efficiency of the exchange process, industrial processes often employ multi-column series operation, periodic switching regeneration, or fixed-bed continuous operation.

[0004] However, due to the typically high viscosity of PAC feedstock solutions (especially high-concentration or high-alkalinity PAC solutions, which can reach hundreds of mPa·s), uneven flow is easily generated when passing through the anion exchange resin bed. This manifests as fluid dynamics problems such as dead zones (areas where the liquid is essentially not flowing), flow deviation (liquid concentrating on local channels with lower resistance), and channeling (preferred flow paths formed along the gaps between resin particles). These phenomena result in a severely uneven distribution of the actual residence time of the high-viscosity PAC liquid within the resin. Some liquid short-circuits and flows out without sufficient exchange, while other liquid remains in the resin for too long, significantly reducing the overall ion exchange efficiency. The chloride ion removal rate and the improvement in alkalinity are far lower than theoretically expected, ultimately affecting the quality stability and preparation efficiency of polyaluminum chloride salt products. Summary of the Invention

[0005] The main objective of this invention is to propose an apparatus and process for improving the basicity and solid alumina content of polyaluminum chloride (PAC). This addresses the problem in existing technologies where, during the preparation of PAC salts using anion exchange resins, the high viscosity of the PAC liquid leads to dead zones, flow deviations, and channeling within the resin. These phenomena result in severely uneven distribution of the actual residence time of the PAC liquid within the resin, with some liquid flowing out without sufficient exchange and others remaining for excessively long periods. This significantly reduces the overall ion exchange efficiency, resulting in a much lower increase in chloride ion removal rate and basicity compared to theoretical expectations. Ultimately, this affects the quality stability and preparation efficiency of the polyaluminum chloride salt product.

[0006] To achieve the above objectives, in a first aspect, the present invention proposes an apparatus for increasing the basicity and solid alumina content of polyaluminum chloride, comprising an installation cylinder, a dispersion mechanism, and multiple ion exchange mechanisms. The installation cylinder has a vertical installation channel formed inside, with an inlet at the top and an outlet at the bottom. The dispersion mechanism is located within the installation channel near the inlet and is used to perform a first dispersion of the incoming polyaluminum chloride salt solution. All the ion exchange mechanisms are arranged vertically at intervals within the installation channel and below the dispersion mechanism. Each ion exchange mechanism includes an ion exchange component and a first dispersion component located below it. The ion exchange component performs a single ion exchange on the incoming polyaluminum chloride salt solution under heat preservation conditions. The first dispersion component performs a redispersion of the exchanged solution. A liquid dripping chamber is formed between any ion exchange component and the first dispersion component. The ion exchange components and the first dispersion component in all the ion exchange mechanisms are arranged alternately in the vertical direction, so that the polyaluminum chloride salt solution undergoes a cycle of ion exchange and redispersion until it is discharged from the outlet.

[0007] The technical solution of this invention, through the arrangement of an installation cylinder, a dispersion mechanism, and multiple ion exchange mechanisms, achieves multi-stage, alternating ion exchange and forced redispersion treatment of high-viscosity polyaluminum chloride salt raw solutions. This effectively suppresses dead zones, flow deviations, and channeling phenomena caused by high viscosity characteristics in traditional single-stage or simple multi-stage fixed beds. The first dispersion and subsequent redispersion steps ensure the uniformity of the solution before entering each resin bed. The liquid droplet chamber provides ample space for radial mixing and redistribution. The alternating ion exchange and dispersion components form a multi-stage "break-exchange-rebreak" flow path, making the flow field of the solution within each ion exchange layer more uniform. The actual effective contact time is closer to the theoretical residence time, thereby significantly improving the chloride ion removal rate and basicity increase. Simultaneously, it improves the stability of solid alumina content and batch-to-batch quality consistency, ultimately improving the overall quality stability and preparation efficiency of polyaluminum chloride salt products. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0009] Figure 1 This is a schematic diagram of the structure of the device provided by the present invention; Figure 2 for Figure 1 A schematic diagram of the structure of the device in the example of the explosion state; Figure 3 for Figure 1 A schematic diagram of the internal structure of the device shown in the example; Figure 4 for Figure 3 A schematic diagram of the structure of the first dispersed component in the example; Figure 5 for Figure 3 A schematic diagram of the structure of the ion exchange component in the example; Figure 6 for Figure 5 A schematic diagram of the internal structure of the ion exchange component in the example; Figure 7 for Figure 3 A schematic diagram of the structure of the distributed mechanism in the example; Figure 8 for Figure 1 The example device is shown in the overall structural diagram. Figure 9 for Figure 8 The example shows a schematic diagram of the internal structure of the entire machine; Figure 10 for Figure 8 The example shows a structural diagram of the entire machine in an exploded state; Figure 11 This is a flowchart illustrating the process of an example of the present invention.

[0010] Explanation of icon numbers: 100. Mounting cylinder; 110. Mounting channel; 120. Liquid inlet; 130. Liquid outlet; 200. Dispersion mechanism; 300. Ion exchange mechanism; 310. Ion exchange component; 320. First dispersion component; 330. Liquid dripping chamber; 311. First dispersion hood; 312. First flow channel; 313. First temperature regulating component; 314. Second flow channel; 315. Ion exchange resin column; 321. First collection funnel; 322. First rotating shaft; 323. First impeller; 324. Second temperature regulating component; 325. First liquid dispersion chamber; 326. Second dispersion hood; 210. Second liquid collecting funnel; 220. Second rotating shaft; 230. Second impeller; 240. Third temperature regulating component; 250. Third dispersion hood; 400. Outer shell; 500. Isolation plate; 600. Filter element; 316. First mounting hole; 317. Second mounting hole.

[0011] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0014] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0015] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0016] Because PAC feedstock solutions typically have high viscosity (especially high-concentration or high-alkalinity PAC solutions, which can reach hundreds to thousands of mPa·s), they are prone to uneven flow when passing through anion exchange resin beds. This manifests as fluid dynamics problems such as dead zones (areas where the liquid is essentially stationary), flow deviation (liquid concentrating in localized channels with lower resistance), and channeling (preferred flow paths formed along the gaps between resin particles). These phenomena result in severely uneven distribution of the actual residence time of the high-viscosity PAC liquid within the resin. Some liquid short-circuits without sufficient exchange, while other liquid remains in the resin for excessively long periods. This leads to a significant decrease in overall ion exchange efficiency, with chloride ion removal rate and alkalinity improvement falling far short of theoretical expectations. Ultimately, this affects the quality stability of polyaluminum chloride salt products and the overall process stability of the preparation process.

[0017] This invention proposes an apparatus and process for improving the basicity of polyaluminum chloride and the content of solid alumina.

[0018] Please see Figures 1 to 11 For ease of understanding, this device for increasing the basicity and solid alumina content of polyaluminum chloride includes an installation cylinder 100, a dispersion mechanism 200, and multiple ion exchange mechanisms 300. The installation cylinder 100 has a vertical installation channel 110 inside. The top of the installation channel 110 has an inlet 120, and the bottom has an outlet 130. The dispersion mechanism 200 is located within the installation channel 110 near the inlet 120 and is used for the initial dispersion of the incoming polyaluminum chloride salt solution. All ion exchange mechanisms 300 are vertically spaced within the installation channel 110 and located below the dispersion mechanism 200. It includes an ion exchange component 310 and a first dispersion component 320 disposed below it. The ion exchange component 310 is used to perform a single ion exchange on the flowing polyaluminum chloride salt original solution under heat preservation conditions. The first dispersion component 320 is used to redisperse the exchanged solution once. A liquid drop chamber 330 is formed between any ion exchange component 310 and the first dispersion component 320. The ion exchange components 310 and the first dispersion components 320 in all ion exchange mechanisms 300 are arranged alternately in the vertical direction so that the polyaluminum chloride salt original solution undergoes a cycle of ion exchange and redispersion in sequence until it is discharged from the outlet 130.

[0019] Specifically, the installation cylinder 100 has a vertically penetrating installation channel 110 inside, with an inlet 120 at the top for receiving the original polyaluminum chloride salt solution and an outlet 130 at the bottom for discharging the final treated solution.

[0020] In actual operation, after the original solution enters the installation channel 110 through the inlet 120, it first contacts and flows through the dispersion mechanism 200. The dispersion mechanism 200 performs the first dispersion treatment on the high-viscosity polyaluminum chloride salt original solution, which initially transforms the solution from a continuous large-volume liquid flow into smaller droplet groups or fine liquid streams, thereby significantly reducing the viscous resistance inside the solution and initially improving the uniformity of subsequent flow.

[0021] Subsequently, the raw solution enters the ion exchange component 310 in the first ion exchange unit 300. This ion exchange component 310 consists of a bed filled with a strongly basic anion exchange resin. The resin particle diameter is typically 0.4–1.0 mm, and the bed height is 400–800 mm. The preferred resin type is quaternary ammonium macroporous or gel-type heat-resistant anion exchange resin, capable of operating under a temperature of 90–100℃. Temperature is maintained by a jacketed heating system installed on the outer wall of the mounting cylinder 100. The heating medium can be saturated steam or heat transfer oil, and the temperature is controlled by multiple independent PID controllers to ensure that the temperature difference between each section does not exceed ±3℃. The raw solution flows downwards through the resin bed at a flow rate of 0.8–3.0 bed volume / hour. During this process, Cl⁻ is replaced by OH⁻ on the resin, achieving a primary ion exchange. The alkalinity of the solution is initially increased, and the morphology of some polymeric aluminum is adjusted, which is beneficial for increasing the subsequent solid alumina content.

[0022] After exchange, the solution immediately enters the first dispersion component 320 below it. This first dispersion component 320 can employ one or more combinations of structures similar to the dispersion mechanism 200, such as a perforated plate, a sieve plate with guide grooves, or a redistribution disk with radially oblique holes, to redistribute the exchanged solution once. The dispersion process breaks the solution back into fine droplets or a uniform thin layer, eliminating concentration gradients or viscosity inhomogeneities that may exist within the resin bed due to localized flow rate differences. After redistribution, the solution enters the next liquid drop chamber 330, further promoting radial mixing and providing uniform feed conditions for the next stage of ion exchange.

[0023] All ion exchange units 300 are arranged vertically in sequence, typically with 3 to 8 stages (preferably 4 to 6 stages), with each stage's ion exchange component 310 alternating with the first dispersion component 320. The feed solution undergoes multiple cycles from top to bottom: "dispersion → dripping → ion exchange → redispersion → dripping → ion exchange...". With each stage of ion exchange, the Cl⁻ removal rate gradually accumulates, and the alkalinity increases accordingly. Each redispersion stage forcibly breaks up any residual flow inhomogeneities from the previous stage, preventing the formation of stable dead zones, flow deviation channels, or channeling paths between resin particles by the high-viscosity solution, thus ensuring that the subsequent resin bed always faces a relatively uniform feed concentration and flow pattern.

[0024] In one specific implementation process, after the polyaluminum chloride salt stock solution enters through the top inlet 120, it first undergoes initial dispersion through the dispersion mechanism 200, forming a preliminary refined liquid stream or droplet group. Subsequently, this liquid stream / droplet group falls into the first liquid droplet chamber 330, and during its descent, it undergoes further natural dispersion and redistribution due to gravity and surface tension, reducing local concentration gradients and flow segregation. When the droplets or liquid stream reach the first ion exchange component 310, they come into full contact with the anion exchange resin or exchange membrane under heat preservation conditions. Chloride ions are selectively exchanged and removed, while anions such as hydroxyl or sulfate ions partially enter the solution, achieving a primary increase in alkalinity and a relative increase in the solid alumina content.

[0025] After the first ion exchange, the solution directly enters the first dispersion component 320 directly below it. Multiple uniformly distributed small holes, slits, or protrusions on the first dispersion component 320 force the solution to be cut, dispersed, and redistributed again, forming new droplet clusters or fine liquid streams. This redistribution process effectively disrupts tiny dead zones, flow deviation channels, or short-circuit paths that may have formed during the upper-level exchange process due to local resistance differences in the resin layer, allowing the solution to regain a more uniform distribution before entering the next-stage ion exchange component 310.

[0026] Subsequently, the redispersed solution falls into the next liquid drop chamber 330, undergoing another process of free fall, droplet collision, and redistribution, further eliminating flow inhomogeneity. The solution then enters the second-stage ion exchange unit 310 to continue chloride ion removal and alkalization reactions. Due to the synergistic effect of the aforementioned multiple dispersions and drop chambers, the actual residence time distribution of the solution within each ion exchange layer is significantly improved: the short-circuit outflow ratio is greatly reduced, excessively long retention areas are alleviated, and the overall exchange efficiency is significantly improved.

[0027] In this embodiment, the ion exchange and redispersion cycle is repeated multiple times in the vertical direction (usually 3 to 8 stages of ion exchange mechanism 300 are set, and the number of stages is determined according to the original solution viscosity, target alkalinity and chloride ion removal rate requirements) until the solution is finally discharged from the outlet 130 at the bottom of the mounting cylinder 100.

[0028] Through the example structure and implementation process, this invention achieves multi-stage, alternating ion exchange and forced redispersion treatment of high-viscosity polyaluminum chloride salt raw solutions, effectively suppressing dead zones, flow deviations, and channeling phenomena caused by high viscosity characteristics in traditional single-stage or simple multi-stage fixed beds. The first dispersion and subsequent redispersion steps ensure the uniformity of the solution before entering each resin bed. The liquid droplet chamber 330 provides sufficient radial mixing and redistribution space. The alternating ion exchange components 310 and dispersion components form a multi-stage "break-exchange-rebreak" flow path, making the flow field of the solution in each ion exchange layer more uniform. The actual effective contact time is closer to the theoretical residence time, thereby significantly improving the chloride ion removal rate and basicity increase, while improving the stability of solid alumina content and batch-to-batch quality consistency, ultimately improving the overall quality stability and preparation efficiency of polyaluminum chloride salt products.

[0029] In one embodiment, the ion exchange component 310 includes a first dispersion cover 311, a first temperature regulating member 313, and multiple ion exchange resin columns 315. The first dispersion cover 311 is installed in the installation channel 110 and is arranged to gradually expand in the vertical direction. Multiple arrayed first flow channels 312 are formed on the first dispersion cover 311 and penetrate the first dispersion cover 311 vertically. The first temperature regulating member 313 is installed below the first dispersion cover 311 and has second flow channels 314 that are the same number as the first flow channels 312 and are arranged in a one-to-one correspondence. The second flow channels 314 penetrate the first temperature regulating member 313 vertically. The number of ion exchange resin columns 315 is the same as the number of second flow channels 314 and they are inserted in a one-to-one correspondence. The ion exchange resin columns 315 can periodically expand and contract within the corresponding second flow channels 314.

[0030] Specifically, the first dispersion hood 311 is installed and fixed on the inner wall of the installation channel 110. Its overall shape gradually expands vertically, meaning its cross-sectional area gradually increases from top to bottom, with a smaller opening at the top and a larger opening at the bottom. This gradual expansion structure allows the solution to be gradually guided outwards during its descent, avoiding concentrated impact on a localized area. Multiple arrayed first flow channels 312 are formed on the first dispersion hood 311, each extending vertically through the entire wall thickness of the first dispersion hood 311. The first flow channels 312 can be circular (typically with a diameter of 1.2–20 mm), elongated, or rhomboid in cross-sectional shape, or in various other forms. The array arrangement includes square arrays, hexagonal close-packed arrays, or staggered arrays, ensuring that the solution enters the lower structure relatively uniformly.

[0031] The first temperature regulating component 313 is securely mounted directly below the first dispersion cover 311, adjacent to or directly abutting the lower end face of the first dispersion cover 311. The first temperature regulating component 313 has second flow channels 314 formed on it, with the same number and position as the first flow channels 312. The second flow channels 314 also vertically penetrate the full thickness of the first temperature regulating component 313. The cross-sectional dimension of the second flow channel 314 is typically slightly larger than or equal to the dimension of the corresponding first flow channel 312, allowing the solution to pass smoothly and enter the subsequent resin column region. The first temperature regulating component 313 is internally equipped with a temperature control structure, such as a jacketed heat exchange channel, an embedded electric heating rod, a semiconductor temperature control element, or a circulating heat transfer medium channel. An externally connected temperature control system maintains the first temperature regulating component 313 within a suitable ion exchange operating temperature range (typically 45℃~100℃), thereby providing a stable thermal environment for the solution.

[0032] The number of multiple ion exchange resin columns 315 is consistent with the number of first temperature regulating components 313, and their positions correspond one-to-one. Each ion exchange resin column 315 is inserted into a corresponding second flow channel 314. The resin columns are typically composed of hydroxyl-type strong basic anion exchange resin (such as quaternary ammonium resin) filled within a porous rigid shell 400 (such as polytetrafluoroethylene or stainless steel sieve tube). The shell 400 has a sufficiently dense number of micropores (pore diameter 20-100 μm) on its wall surface to allow the solution to enter and exit the resin bed radially, while preventing resin particle loss. The outer diameter of each resin column matches the inner diameter of the corresponding second flow channel 314, achieving a tight insertion while allowing a certain degree of radial micro-expansion space.

[0033] In one specific implementation, the high-viscosity polyaluminum chloride salt original solution (or the droplet group after upper dispersion) first contacts the upper end of the first dispersion hood 311. Since the first dispersion hood 311 is vertically expanding, the solution gradually expands and flows radially outward within the hood, while simultaneously being cut and dispersed into numerous fine liquid columns or jets through multiple arrayed first flow channels 312, flowing downwards. This process effectively prevents the solution from directly impacting the lower resin layer in a large continuous flow, initially suppressing the occurrence of flow deviation and local overload.

[0034] The solution then enters the second flow channel 314 on the first temperature regulating element 313. Since the second flow channel 314 corresponds one-to-one with the first flow channel 312 and is aligned, the solution can maintain its original dispersion state and directly enter the corresponding ion exchange resin column 315. During this stage, the first temperature regulating element 313 controls the temperature of the flowing solution, heating or maintaining it to a suitable temperature before it enters the resin column, significantly improving the reaction rate of chloride ions with the exchange groups on the resin and the utilization rate of the exchange capacity.

[0035] After the solution enters the ion exchange resin column 315, it mainly flows downward along the axial direction. Inside the resin column, the high-viscosity solution comes into full contact with the resin particles, chloride ions are selectively adsorbed and removed, the alkalinity gradually increases, and the relative content of solid alumina increases accordingly. Due to the small diameter of each resin column (usually 8-25 mm outer diameter), the radial diffusion distance of the solution within a single column is short, and the dead zone volume is significantly reduced. At the same time, multiple resin columns arranged in parallel form a distributed exchange path, effectively dispersing the total flow and avoiding channeling or short-circuiting caused by high viscosity within a single exchange bed.

[0036] In one embodiment, the ion exchange resin column 315 is capable of periodically expanding and contracting within the corresponding second flow channel 314. Specifically, the resin column shell is made of a porous polymer material with a certain degree of elasticity (such as modified polytetrafluoroethylene or polyvinylidene fluoride), or a small amount of elastic particles / fibers are mixed into the resin filling layer; or the temperature of the first temperature regulating element 313 is periodically changed (for example, with a period of 5 to 15 minutes, small-amplitude temperature rises and falls in the range of 45°C to 65°C), utilizing the thermal expansion and contraction characteristics and swelling / shrinkage behavior of the resin itself to achieve periodic micro-expansion and contraction of the resin column volume (the radial expansion rate is usually controlled at 3% to 12%). This expansion and contraction action causes dynamic changes in the gaps between resin particles, causing possible micro-adhesion layers or locally dense areas to be periodically loosened and rearranged, significantly reducing the probability of high-viscosity solutions forming stable dead zones or flow deviation channels inside the resin bed, and further improving the uniformity of residence time distribution.

[0037] Through the gradual dispersion of the first dispersion hood 311, the multi-point cutting of the array flow channels, the precise temperature control of the first temperature regulating component 313, and the distributed exchange of multiple thin-diameter resin columns, combined with the periodic expansion and contraction of the resin columns, the ion exchange component 310 of this embodiment can effectively alleviate the dead zones, flow deviations, and channeling problems commonly encountered in traditional fixed-bed exchange processes of high-viscosity polyaluminum chloride solutions. This makes the actual effective contact area and residence time of the solution within the exchange layer more uniform, thereby achieving a higher chloride ion removal rate, a more significant increase in alkalinity, and a more stable increase in solid alumina content, ultimately improving the consistency of polyaluminum chloride product quality and the overall efficiency of the preparation process. Simultaneously, the first temperature regulating component 313 precisely maintains the temperature of the channel containing each resin column, keeping the exchange process within a suitable high-temperature range (preferably 85–98°C), accelerating the replacement rate of Cl⁻ and OH⁻. Driven by periodic liquid inlet pulses, the resin columns undergo restricted expansion and contraction, further breaking down the stable flow dead zones and channeling easily formed in high-viscosity solutions, significantly increasing the actual contact area and renewal frequency between the solution and resin.

[0038] In one embodiment, the first dispersing component 320 includes a first collecting funnel 321, a first rotating shaft 322, a second temperature regulating component 324, and at least two first blades 323. The first collecting funnel 321 is installed in the installation channel 110 and is sealed to the inner wall of the installation cylinder 100. A first mounting hole 316 is formed at the bottom of the first collecting funnel 321. The first rotating shaft 322 is rotatably installed in the first mounting hole 316 by a bracket, and the first rotating shaft 322 extends vertically downward out of the first mounting hole 316. All the first blades 323 are circumferentially spaced on the first rotating shaft 321. The shaft 322 is located on the outer periphery, and all the first blades 323 protrude from the first mounting hole 316. A first liquid dispersion chamber 325 is formed on the second temperature regulating member 324, which is vertically penetrating. The first liquid dispersion chamber 325 is gradually expanded downwards. The second temperature regulating member 324 is installed below the first liquid collecting funnel 321, and the first blades 323 are accommodated in the first liquid dispersion chamber 325. The first blades 323 can rotate and disperse the polyaluminum chloride salt original solution under the flushing action of the polyaluminum chloride salt original solution flowing into the first mounting hole 316 through the first liquid collecting funnel 321.

[0039] Specifically, the first collecting funnel 321 is fixedly installed on the inner wall of the installation channel 110 and is circumferentially sealed to the inner wall of the installation cylinder 100, allowing the solution to flow downwards only through the bottom of the funnel. The first collecting funnel 321 is generally inverted conical or truncated conical in shape, with a first installation hole 316 at the center of its bottom. The diameter of this installation hole is typically 20–60 mm, with the specific size determined based on the single-stage treatment flow rate. After the solution flows out from the ion exchange component 310 above, it first enters the open end of the first collecting funnel 321 and, under the guidance of gravity and the conical surface, converges towards the center, ultimately being discharged downwards through the first installation hole 316. The first rotating shaft 322 is rotatably installed in the first installation hole 316 via a bracket. The main body of the rotating shaft extends vertically downwards and passes through the first installation hole 316, with its lower end exposed below the funnel. The bracket is usually fixed around the wall of the first mounting hole 316 by several radially arranged thin rods or a cross-shaped support structure, ensuring that the axis of the rotating shaft is basically coincident with the center line of the mounting channel 110, while allowing it to rotate freely around its own axis.

[0040] At least two first blades 323 are evenly spaced circumferentially and fixedly connected to the outer circumferential surface of the first rotating shaft 322. All first blades 323 are located below the first mounting hole 316, that is, completely exposed below the liquid outlet 130 of the first liquid collecting funnel 321. The blades can be of various forms, such as straight blades, curved blades, or spiral blades, and the number of blades is generally 2 to 6. The blade material is preferably corrosion-resistant, wear-resistant, and has a smooth surface, such as stainless steel, titanium alloy, or polymer composite material.

[0041] The second temperature regulating component 324 has a first liquid dispersion chamber 325 vertically extending through it. This chamber gradually expands downwards, meaning its cross-sectional area increases progressively from the upper inlet to the lower outlet. The upper inlet is aligned with and slightly larger than the first mounting hole 316. The upper part of the first liquid dispersion chamber 325 may be cylindrical or slightly constricted, while the lower part may be funnel-shaped or inverted conical. The second temperature regulating component 324 also has a temperature control structure (such as a jacketed heat exchange channel, an electric heating element, or a heat transfer oil circulation channel) inside, which maintains the solution temperature in the chamber within a suitable range (generally 80℃~100℃) through an external temperature control system.

[0042] In one specific implementation, the polyaluminum chloride salt solution from the upper ion exchange component 310 first falls into the open end of the first collecting funnel 321. Due to the collecting effect of the funnel, the solution is guided to the center and concentrated through the first mounting hole 316 at a high flow rate. As the solution flows through the first mounting hole 316, it directly acts on the surface of the first blade 323 located below the hole and exposed, generating a tangential thrust that drives the first rotating shaft 322 and all the first blades 323 to rotate synchronously. The rotating blades exert strong shearing, impact, and dispersion effects on the continuously falling solution column or jet, forcibly cutting, breaking, and throwing the solution, which may still have some continuity, towards the side wall and lower space of the first liquid dispersion chamber 325, forming a large number of fine droplets, liquid films, or turbulent liquid jets.

[0043] Meanwhile, the second temperature regulator 324 continuously maintains or heats the solution entering the first liquid dispersion chamber 325. The vertically expanding structure of the chamber allows sufficient space for the droplets / liquid jets dispersed by the blades to diffuse in all directions during their descent, preventing excessive collisions and merging between droplets. It also prolongs the residence time of droplets within the chamber, further promoting natural redistribution and surface renewal. The chamber walls can be kept smooth or have micro-guiding textures to assist in the uniform spreading of droplets.

[0044] After undergoing the combined effects of mechanical forced dispersion by the first impeller 323 and natural diffusion in the first liquid dispersion chamber 325, the solution falls into the lower liquid drop chamber 330 or directly enters the next-stage ion exchange component 310 in a highly dispersed state. This highly dispersed state significantly eliminates any localized high-concentration zones or viscosity gradients that may remain in the upper-stage ion exchange process, resulting in a more uniform radial and circumferential distribution of the solution entering the next-stage ion exchange component 310. This effectively suppresses the formation of biased flow, channeling, and dead zones, thereby improving the contact efficiency and chloride ion removal uniformity of the next-stage ion exchange.

[0045] In this embodiment, after leaving the ion exchange component 310, the solution is first collected and accelerated by the first collecting funnel 321, and then impacts the rotating first impeller 323 in the form of a jet at the first mounting hole 316, where it is forced to undergo high-intensity mechanical shearing and dispersion; simultaneously, it completes secondary radial expansion and redistribution within the gradually expanding first liquid dispersion chamber 325. The second temperature regulating component 324 maintains a stable temperature for the solution in the dispersion chamber, preventing local over-agglomeration or viscosity rebound due to temperature drop after high-temperature exchange. The entire process effectively eliminates any residual concentration gradients, flow rate unevenness, and local high-viscosity areas that may remain after the previous stage of ion exchange, allowing the solution to enter the next liquid droplet chamber 330 in a highly uniform state of fine droplets or thin layers, providing uniform and stable liquid inlet conditions for the next stage of ion exchange component 310. (See attached specification) Figure 4 For example, it should be clearly stated that the first mounting hole 316 is attached. Figure 4 The column area below the second dispersion cover 326 and the area corresponding to the location of the mounting bracket.

[0046] In one embodiment, the first blade 323 is spirally arranged in the vertical direction.

[0047] Specifically, the first blade 323 no longer adopts a straight or curved blade form distributed in a plane at the same height along the axial direction. Instead, each blade is arranged in a continuous or segmented spiral winding along the axial direction of the first shaft 322. The spiral direction can be left-handed or right-handed, and the spiral angle is usually controlled between 15° and 45°, preferably between 20° and 38°. The axial projection height is determined according to the number of spiral turns and the total length, usually so that a single blade covers a height range of 1.2 to 4.5 times the diameter of the first mounting hole 316 in the vertical direction. The blade thickness is maintained at 2 to 10 mm, and the surface can be kept smooth or have small guiding textures to further enhance the ability to disturb the liquid flow. The blade material is still selected from acid-resistant, corrosion-resistant stainless steel, titanium alloy, reinforced polytetrafluoroethylene, or polymer composite materials with a certain degree of rigidity.

[0048] In a specific implementation, when the polyaluminum chloride salt solution flows out from the first mounting hole 316 at the bottom of the first collecting funnel 321 and washes onto the first impeller 323, the solution first contacts the surface of the impeller at the uppermost end of the spiral path because the impeller is arranged in a vertical spiral. The impact force of the solution not only generates a circumferential thrust to drive the shaft to rotate, but also, due to the existence of the spiral structure, the solution is forced to undergo a spiral flow trajectory downward along the axial direction as it is pushed by the impeller. That is, at the moment of contact with the impeller, the solution is subjected to strong radial and tangential shearing and dispersion, and also obtains a significant axial velocity component due to the helical angle, thus forming a complex spiral-centrifugal dispersion flow.

[0049] The spiral flow path causes the solution to diffuse within the first liquid dispersion chamber 325 not only radially, but also to rotate and spiral downwards simultaneously. The solution column or jet exhibits a distinct spiral trajectory within the chamber, with multiple collisions, stretching, tearing, and recombination among the droplets, significantly increasing the surface renewal frequency of the liquid film and the average number of droplet collisions. Simultaneously, because the spiral path extends the effective residence path and time of the solution within the first liquid dispersion chamber 325 of the second temperature regulator 324, high-viscosity solutions have a greater opportunity to achieve natural relaxation of the viscosity gradient and homogenization of the local concentration field under controlled temperatures.

[0050] After the combined dispersion effect driven by the propeller blades, the solution leaves the lower end of the first liquid dispersion chamber 325 in the form of finer and more uniformly distributed droplets or thin liquid films, falling into the liquid droplet chamber 330 below or directly entering the next stage ion exchange component 310. At this time, the radial, circumferential, and axial uniformity of the solution is further enhanced, and local high-concentration agglomeration or areas with high viscosity are effectively dispersed, creating more favorable hydrodynamic conditions for uniform penetration and sufficient contact in the subsequent ion exchange component 310.

[0051] By setting the first blade 323 to be arranged in a vertical spiral, this embodiment further enhances the forced dispersion strength and dispersion uniformity of the first dispersion component 320 on the high-viscosity polyaluminum chloride salt solution without adding an external power source. It effectively suppresses the flow segregation and small dead zones that may remain in the solution after the upper ion exchange, making the overall flow field in the multi-stage ion exchange process closer to the ideal uniform distribution state. This results in higher chloride ion selective removal efficiency, a greater increase in alkalinity, and a more stable increase in solid alumina content, ultimately improving the batch quality consistency and preparation efficiency of polyaluminum chloride salt products.

[0052] In one embodiment, the first dispersing component 320 further includes a second dispersing cover 326, which is mounted on the top of the first rotating shaft 322 and located inside the first liquid collecting funnel 321. The second dispersing cover 326 has a structure that gradually expands and then shrinks vertically downwards.

[0053] Specifically, the second dispersion hood 326 has a special axisymmetric structure that gradually expands and then contracts downwards along the vertical direction. That is, starting from the upper inlet, it first gradually expands radially to the maximum cross-sectional area, and then gradually contracts radially inwards to the lower outlet. The second dispersion hood 326 resembles a "waist drum" or a "double-cone transition shape." The semi-apex angle of the upper expanding section is generally controlled between 12° and 32°, and the semi-apex angle of the lower contracting section is generally controlled between 8° and 28°. The maximum cross-sectional area is usually located at 45% to 65% of the total height of the hood. The outer diameter of the second dispersion hood 326 at its maximum cross-section is generally 0.55 to 0.85 times the inner diameter of the first collecting funnel 321 to ensure that the solution can smoothly collect downwards without significant throttling. The material of the second dispersion hood 326 is preferably corrosion-resistant polytetrafluoroethylene, stainless steel, or reinforced engineering plastic, and the inner wall surface maintains a high degree of smoothness or is equipped with fine guiding textures.

[0054] In one specific implementation, the polyaluminum chloride salt solution from the upper ion exchange component 310 first falls into the open area of ​​the first collecting funnel 321. Since the second dispersion hood 326 is fixed to the top of the first rotating shaft 322 and rotates synchronously with it, the solution, upon entering the first collecting funnel 321, first contacts the outer surface and upper inlet of the rotating second dispersion hood 326. Guided by the gradually expanding section at the top of the second dispersion hood 326, the solution gradually expands radially outward along the outer wall and inner cavity of the hood. Simultaneously, due to the high-speed rotation of the hood, it acquires an additional circumferential velocity component, forming a diffusion flow state with a rotational effect.

[0055] As the solution descends along the outer wall of the second dispersion hood 326 to near its maximum cross-section, it gradually re-converges towards the center as the hood enters its converging section. Under the combined action of centrifugal force and the hood wall, some solution is thrown towards the inner wall of the first collecting funnel 321, while the remaining solution enters the inner cavity of the lower converging section of the hood. The converging effect of the converging section increases the solution flow rate and further enhances the circumferential rotation intensity. Before leaving the lower outlet of the second dispersion hood 326, the solution forms a relatively uniform rotating liquid film or jet. Subsequently, this rotating liquid jet / film concentrates through the first mounting hole 316 at the bottom of the first collecting funnel 321, rushing at a high tangential velocity towards the first impeller 323 located below.

[0056] Because the solution has already acquired significant circumferential rotational kinetic energy and preliminary radial uniform distribution during its passage through the second dispersion hood 326, when it reaches the first impeller 323, the scouring effect on the impeller not only generates a more stable rotational driving force, but also, due to the rotational component of the incoming flow itself, makes the shearing and dispersion process of the impeller on the solution more intense and comprehensive. Under the action of the first impeller 323, the rotating liquid stream is further cut and torn and strongly dispersed into the first liquid dispersion chamber 325, forming a large number of fine droplet clusters with high initial tangential velocities. These droplets continue to maintain a rotational diffusion trend in the first liquid dispersion chamber 325 of the second temperature regulating element 324, significantly prolonging the number of collisions and liquid film tearing and recombination between droplets, further reducing droplet size and improving distribution uniformity.

[0057] By adding a second dispersion cover 326 that rotates synchronously with the shaft inside the first collection funnel 321, and adopting a specific structure of gradual expansion followed by gradual contraction, this embodiment achieves pre-dispersion, pre-rotation, and pre-homogenization treatment before the solution reaches the first mounting hole 316. This effectively alleviates the local impact, liquid column merging, and initial flow deviation tendencies that are easily formed when high-viscosity solutions fall directly and concentrated. This allows the mechanical dispersion effect of the subsequent first impeller 323 to exert its maximum efficiency under more uniform inflow conditions. Finally, when the solution enters the next-stage liquid drop chamber 330 or the next-stage ion exchange component 310, its radial and circumferential concentration gradients and viscosity non-uniformity are significantly reduced. The flow field uniformity within each ion exchange layer is further improved, the chloride ion removal efficiency and alkalinity improvement are closer to the theoretical values, and the batch stability of solid alumina content is also significantly improved.

[0058] In one embodiment, the dispersion mechanism 200 includes a second collecting funnel 210, a second rotating shaft 220, a third temperature regulating element 240, and at least two second blades 230. The second collecting funnel 210 is installed in the installation channel 110 and is sealed to the inner wall of the installation cylinder 100. A second mounting hole 317 is formed at the bottom of the second collecting funnel 210. The second rotating shaft 220 is rotatably installed in the second mounting hole 317 by a bracket, and the second rotating shaft 220 extends vertically downward out of the second mounting hole 317. All the second blades 230 are circumferentially spaced on the second rotating shaft 220. The outer periphery of the second blade 230 is exposed through the second mounting hole 317. The second blade 230 is spirally arranged in the vertical direction. A second liquid dispersion chamber is formed on the third temperature regulating member 240 and is arranged vertically through the second liquid dispersion chamber. The second liquid dispersion chamber is gradually expanded in the vertical direction downward. The third temperature regulating member 240 is installed below the second liquid collecting funnel 210. The second blade 230 is accommodated in the second liquid dispersion chamber. The second blade 230 can rotate and disperse the polyaluminum chloride salt original solution under the flushing action of the polyaluminum chloride salt original solution flowing into the second mounting hole 317 through the second liquid collecting funnel 210.

[0059] Specifically, the second collecting funnel 210 has an overall inverted cone or truncated cone structure, with a second mounting hole 317 at the center of its bottom. After the solution flows out from the previous stage ion exchange component 310 or the previous stage dispersion component, it first enters the open end of the second collecting funnel 210, and under the guidance of gravity and the conical wall, it converges towards the center, and finally flows out through the second mounting hole 317 at a high flow rate.

[0060] At least two second blades 230 are evenly spaced circumferentially and fixedly connected to the outer circumferential surface of the second rotating shaft 220. All second blades 230 are located below the second mounting hole 317, that is, completely exposed below the liquid outlet 130 of the second liquid collecting funnel 210. The second blades 230 are arranged in a spiral along the vertical direction, that is, each blade is continuously or segmentally spirally wound along the axial direction of the second rotating shaft 220, and the spiral direction can be left-handed or right-handed. The blade material is selected from acid-resistant, wear-resistant, and smooth-surfaced stainless steel, titanium alloy, reinforced polytetrafluoroethylene, or polymer composite materials.

[0061] The third temperature regulating component 240 is securely installed directly below the second liquid collecting funnel 210, maintaining an adjacent position or a slight gap with the lower end face of the second liquid collecting funnel 210. A second liquid dispersion chamber is vertically integrated within the third temperature regulating component 240. This chamber gradually expands downwards, meaning its cross-sectional area gradually increases from the upper inlet to the lower outlet. The upper inlet is aligned with and slightly larger than the second mounting hole 317. The upper part of the chamber may be cylindrical or slightly constricted, while the lower part may be flared or inverted conical. The third temperature regulating component 240 contains a temperature control structure (jacketed heat exchange channel, electric heating element, semiconductor temperature control module, or heat-conducting medium circulation channel, etc.), which, through an externally connected temperature control system, stably maintains the solution temperature within the chamber within a suitable ion exchange operating range. In one specific implementation, the polyaluminum chloride salt solution from the upper structure first falls into the open end of the second collecting funnel 210. Due to the collecting and guiding effect of the funnel, the solution is directed to the center and concentrated through the second mounting hole 317 at a certain flow rate. As the solution flows through the second mounting hole 317, it directly acts on the exposed surface of the second impeller 230 located below the hole. Since the second impeller 230 is arranged in a vertical spiral, the solution first contacts the surface of the impeller at the uppermost end of the spiral path, and the resulting impact force includes both circumferential thrust and axial components, driving the second shaft 220 and all the second impellers 230 to rotate synchronously. The rotating impeller blades exert strong three-dimensional shearing, impact, stretching, and dispersion effects on the falling solution column or jet, forcing the solution to move downward along the spiral trajectory during the pushing process, forming a composite flow with obvious axial propulsion and circumferential rotation. (See attached instruction manual) Figure 7 For example, it should be clearly stated that the second mounting hole 317 is attached. Figure 7 The column area below the third dispersion cover 250 and the area corresponding to the location of the mounting bracket.

[0062] The solution continuously falls along a spiral-centrifugal path within the second liquid dispersion chamber, resulting in frequent collisions, tearing, reorganization, and surface renewal between droplet groups or liquid films. Simultaneously, the third temperature control unit 240 continuously heats or maintains the temperature of the solution flowing through the chamber, optimizing the flowability of the high-viscosity solution under controlled temperatures, rapidly relaxing local viscosity gradients, and significantly reducing concentration field inhomogeneity.

[0063] After being dispersed by the spiral force of the second impeller 230 and diffused by the gradual expansion and heat preservation of the second liquid dispersion chamber, the solution leaves the lower end of the third temperature regulating element 240 in a highly dispersed state with a certain rotational kinetic energy, falling into the liquid droplet chamber 330 below or directly entering the next stage ion exchange component 310. At this time, the uniformity of solution distribution in the radial, circumferential, and axial directions is enhanced, and local high-concentration agglomeration and high viscosity areas are effectively eliminated, providing more favorable hydrodynamic conditions for uniform penetration, sufficient contact, and stable exchange in the subsequent ion exchange component 310.

[0064] In this embodiment, the dispersion mechanism 200 repeatedly applies a dispersion logic similar to that of the first dispersion component 320 in the middle and lower parts of the device or in the later stages of multi-stage exchange. However, it is adaptively enhanced to address the potential changes in solution properties after multi-stage exchange (viscosity may decrease slightly but still exhibit certain non-Newtonian characteristics, and local concentration gradients may reappear). The combination of the propeller blades and the gradually expanding dispersion chamber significantly improves the pre-dispersion uniformity of the solution before entering the next stage of ion exchange, effectively suppressing secondary flow deviation, channeling, and dead zones that are prone to occur in the later stages of multi-stage exchange. This further improves the overall chloride ion removal rate, the increase in alkalinity, and the stability of the solid alumina content of the entire device.

[0065] In one embodiment, the dispersion mechanism 200 further includes a third dispersion cover 250, which is mounted on the top of the second rotating shaft 220 and located inside the second liquid collecting funnel 210. The third dispersion cover 250 has a structure that gradually expands and then shrinks vertically downwards.

[0066] Specifically, the second dispersion hood 326 has an axisymmetric structure that expands and then contracts vertically downwards, meaning it first expands radially to its maximum cross-sectional area from the upper inlet and then gradually converges radially inwards to its lower outlet. Its overall shape resembles a "waist drum" or a "double-cone transition shape." The outer diameter of the third dispersion hood 250 at its maximum cross-section is generally 0.50 to 0.88 times the inner diameter of the second collecting funnel 210, ensuring smooth downward flow of the solution and avoiding significant local throttling resistance. The third dispersion hood 250 is made of acid-resistant materials, such as polytetrafluoroethylene, 316L stainless steel, Hastelloy, or reinforced engineering plastics, with a wall thickness generally ranging from 2.5 to 9 mm. Both the inner and outer walls maintain a high degree of smoothness. In some embodiments, fine spiral guide lines or radial microgrooves can be provided on the inner wall to further enhance liquid film distribution.

[0067] In one specific implementation, the polyaluminum chloride salt solution from the previous stage ion exchange component 310 or the previous stage dispersion component first enters the open area of ​​the second collection funnel 210. Since the third dispersion hood 250 is fixed to the top of the second rotating shaft 220 and rotates synchronously with the second rotating shaft 220 and the second impeller 230, the solution, upon falling in, first contacts the upper inlet and outer surface of the rotating third dispersion hood 250. Guided by the geometry of the upper gradually expanding section, the solution gradually expands radially outward along the outer wall and inner cavity of the hood, while simultaneously being endowed with a significant circumferential velocity component due to the rotation of the hood, forming a pre-rotating diffusion flow state.

[0068] As the solution continues to flow down the outer wall of the third dispersion hood 250 to near its maximum cross-section, the hood enters a converging section, and the solution flow channel begins to converge. Part of the solution is drawn back towards the center, while another part is thrown towards the inner wall of the second collecting funnel 210 by centrifugal force. The convergence effect of the converging section increases the solution flow rate and further enhances the circumferential rotation intensity. Before leaving the lower outlet of the third dispersion hood 250, the solution has essentially formed a relatively uniform rotating liquid film or a rotating liquid jet with tangential velocity. Subsequently, this rotating liquid jet / film concentrates through the second mounting hole 317 at the bottom of the second collecting funnel 210, and is swept towards the second impeller 230 located below at a high combined tangential and axial velocity.

[0069] Because the solution has undergone pre-dispersion, pre-rotation, and initial homogenization of concentration and viscosity field during its passage through the third dispersion hood 250, the initial distribution of the incoming flow upon reaching the second impeller 230 is significantly better than that of an untreated concentrated liquid column. The scouring effect on the second impeller 230 is therefore more stable and uniform, reducing fluctuations in the driving torque and making the rotation of the second shaft 220 smoother. Upon receiving the incoming flow with its initial circumferential velocity, the rotating helical second impeller 230 further amplifies and superimposes the three-dimensional shearing, stretching, tearing, and scattering effects on the solution. The spiral-centrifugal composite flow trajectory formed by the solution within the second liquid dispersion chamber is more pronounced, significantly increasing the collision frequency of droplets, the number of liquid film tearing and reorganization cycles, and the surface renewal rate.

[0070] After undergoing multiple superimposed effects of pre-dispersion by the third dispersion hood 250, forced dispersion by the second impeller 230, and gradual expansion and heat preservation diffusion in the second liquid dispersion chamber, the solution leaves the lower end of the third temperature regulating element 240 in a highly dispersed state with strong rotational kinetic energy and uniform temperature distribution, falling into the liquid droplet chamber 330 below or directly entering the next stage ion exchange component 310. At this time, the radial and circumferential concentration gradients, viscosity non-uniformity, and flow segregation phenomena of the solution are significantly weakened, providing more ideal feeding conditions for uniform penetration within the subsequent ion exchange layer, extending the effective contact time, and suppressing local over-exchange or under-exchange.

[0071] By adding a third dispersion hood 250 that rotates synchronously with the second rotating shaft inside the second collection funnel 210 and adopting a specific structure of gradual expansion followed by gradual contraction, this embodiment achieves a pretreatment function corresponding to the second dispersion hood 326 in the first dispersion component 320 in the subsequent stages of the dispersion mechanism 200. This effectively compensates for the tendency of local aggregation and flow field inhomogeneity that may reappear in the later stages of multi-stage ion exchange, further optimizing the overall hydrodynamic performance of the entire multi-stage dispersion-exchange system. Ultimately, it significantly improves the uniformity and thoroughness of chloride ion deep removal, achieves a wider range of controllable improvement in alkalinity, and enables more stringent control over batch-to-batch fluctuations in solid alumina content.

[0072] In one embodiment, the device further includes a housing 400 and a partition plate 500. The housing 400 has an installation chamber, and the partition plate 500 is installed in the installation chamber. The partition plate 500 divides the installation chamber into a plurality of arrayed placement through holes. The number of placement through holes is the same as the number of installation cylinders 100, and one installation cylinder 100 is installed in each one of them.

[0073] Specifically, the outer casing 400 is typically made of corrosion-resistant, pressure-resistant, and rigid materials, such as stainless steel, fiberglass, reinforced polypropylene, or carbon steel with an acid-resistant coating. The outer casing 400 has a rectangular, cylindrical, or polygonal closed structure, forming a continuous installation chamber inside. The cross-sectional dimensions of the chamber are determined according to the required processing scale, generally accommodating an array of 4 to 50 installation cylinders 100. The top of the outer casing 400 is equipped with a solution inlet manifold and distribution components, while the bottom is equipped with a liquid collection chamber and a main liquid outlet 130. Inspection doors, viewing windows, and temperature / pressure detection interfaces may also be provided on the side walls or top.

[0074] The isolation plate 500 is fixedly installed in the middle or slightly above the mounting chamber. It is typically made of a material matching the outer shell 400 and is reliably fixed and sealed to the inner wall of the outer shell 400 via bolts, welding, or snap-fit ​​methods. The isolation plate 500 has multiple placement through holes arranged in a rectangular array, a regular hexagonal honeycomb array, or a uniformly distributed circular array. The center distance between each through hole is determined based on the outer diameter of the mounting cylinder 100 and the required flow channel clearance. The inner diameter of each placement through hole is clearance-fitted or interference-fitted with the corresponding outer diameter of the mounting cylinder 100, ensuring that the mounting cylinder 100 can be stably embedded without significant misalignment. Simultaneously, sealing ring grooves or boss structures are provided around the through holes to achieve fluid isolation between the upper and lower parts of the chamber after the mounting cylinder 100 is inserted.

[0075] In one specific implementation, multiple installation cylinders 100 (each installation cylinder 100 contains a first liquid collecting funnel 321, a first dispersion component 320, a first temperature regulating component 313, a first liquid dispersion chamber 325, etc.) are inserted one by one into the corresponding placement through holes from the top or side inspection ports of the outer shell 400 until the upper flange or positioning boss of the installation cylinder 100 is attached and fixed to the upper surface of the isolation plate 500. After installation, the isolation plate 500 clearly divides the entire installation chamber into an upper liquid inlet distribution area and a lower liquid outlet collection area. In the upper liquid inlet distribution area, the polyaluminum chloride salt raw solution from the raw material solution inlet manifold is evenly distributed to the top liquid inlet 120 of each installation cylinder 100 through the distribution pipeline or porous distribution plate. The processing inside each installation cylinder 100 (including solution collection, pre-dispersion, propeller blade forced dispersion, temperature-controlled droplet diffusion, and dripping to the lower ion exchange layer, etc.) is carried out independently and without interference.

[0076] After undergoing one or more stages of dispersion-exchange treatment within each mounting cylinder 100, the solution flows out from the bottom of the mounting cylinder 100 in the form of droplets or a thin liquid film, falling directly into the liquid collection area below the isolation plate 500. The bottom of the liquid collection area is equipped with an inclined guide surface or a collection trough, where the treated liquid flowing out of all mounting cylinders 100 converges and is discharged through the main outlet 130, or, in a multi-stage series arrangement, is sent to the inlet 120 of the next stage housing 400 through connecting pipes. Due to the presence of the isolation plate 500, there is no direct flow path between the upper liquid distribution area and the lower liquid collection area, effectively avoiding short-circuit mixing or cross-contamination between treated and untreated solutions.

[0077] By setting an isolation plate 500 inside the outer casing 400 and forming multiple one-to-one placement through holes, this embodiment achieves physical isolation and fluid separation for multi-cylinder parallel or modular arrangements, making each mounting cylinder 100 an independent operating unit. In actual operation, even if one mounting cylinder 100 is temporarily shut down due to local blockage, exchanger failure, or maintenance needs, the remaining mounting cylinders 100 can still maintain normal continuous operation, and the overall processing capacity of the entire device will not fluctuate significantly. At the same time, the independence of the inlet and outlet liquid flows of each mounting cylinder 100 significantly improves the uniformity of solution distribution among multiple cylinders, reduces local overload or underload phenomena caused by uneven flow distribution, and makes the residence time distribution, flow field uniformity, and exchange efficiency in each ion exchange unit tend to be consistent. Ultimately, this results in higher batch-to-batch stability of chloride ion removal rate and alkalinity improvement, better control accuracy of solid alumina content, and simultaneous improvement in the reliability and maintenance convenience of the entire machine.

[0078] In one embodiment, a filter element 600 is also included, which is installed in the mounting chamber and is located above the isolation plate 500.

[0079] Specifically, the filter element 600 typically adopts a flat, folded, or cylindrical structure and is fixedly installed in the upper space of the installation chamber, that is, at a certain height above the upper surface of the isolation plate 500 (generally within the range of 15% to 45% of the total height of the installation chamber), to ensure that it is located within the liquid distribution area and upstream of the liquid inlet 120 at the top of all installation cylinders 100. The overall cross-sectional shape of the filter element 600 matches the inner cavity of the outer shell 400 and can be rectangular, circular, or polygonal. The edges are circumferentially sealed and fixed to the inner wall of the outer shell 400 by flanges, compression rings, or sealing strips, so that the polyaluminum chloride salt raw solution from the raw material solution inlet manifold must all pass through the filter element 600 before reaching the distribution space above the isolation plate 500.

[0080] The filter medium of filter element 600 is preferably made of acid-resistant, temperature-resistant materials with certain mechanical strength, such as polypropylene felt, polytetrafluoroethylene sintered plate, 316L stainless steel sintered mesh, titanium fiber felt, or multi-layer composite filter cloth. The filtration accuracy is generally controlled between 5 and 150 μm, selected according to the particle size distribution of suspended solids in the feed liquid and the process cleanliness requirements. The effective filtration area of ​​filter element 600 is typically 1.2 to 3.8 times the cross-sectional area of ​​the outer shell 400 to ensure that the pressure drop does not exceed 0.015 to 0.08 MPa at the design flow rate. In some embodiments, filter element 600 may be equipped with a backwashing pipeline interface or a manual / automatic drain valve to restore permeability through backwashing or partial sludge removal after a period of operation.

[0081] In one specific implementation process, the polyaluminum chloride salt raw solution (which typically contains a small amount of undissolved aluminum hydroxide particles, flocculated residue, mechanical impurities, or small foreign matter introduced during raw material transportation) enters the upper part of the installation chamber through the main inlet pipe at the top of the outer shell 400, and first acts uniformly on the upper surface of the filter element 600. Driven by gravity and the pressure difference of the inlet pressure, the solution passes through the filter medium. Larger particles and some colloidal suspended matter are intercepted in the filter cake layer or media pores on the upstream side of the filter element 600, while the clarified solution flows out from the lower surface of the filter element 600 and enters the inlet distribution area above the isolation plate 500.

[0082] After filtration, the solution is further evenly distributed within the distribution zone through a porous distribution plate, guide channel, or diversion pipeline to the top inlet 120 of each mounting cylinder 100 above the placement through-hole. The processing inside each mounting cylinder 100 (including collection in the first collecting funnel 321, pre-dispersion in the second dispersion hood 326, spiral dispersion in the first impeller 323, gradual temperature-controlled diffusion in the first liquid dispersion chamber 325, and dripping onto the ion exchange layer, etc.) is all based on a feed with higher cleanliness. At this time, since most of the solid particles that may cause blockage or local channeling of the ion exchange resin / packing layer have been intercepted in advance, the flow channels, impeller surfaces, and packing pores in the subsequent multi-stage dispersion-exchange units remain unobstructed for a longer period of time, and the uniformity of liquid distribution and effective contact area are maintained at a high level.

[0083] The arrangement of the filter element 600 above the separator plate 500 ensures that all intercepted solid impurities remain in the inlet distribution area and do not fall into the outlet collection area or mix with the treated liquid, thus avoiding secondary contamination. Simultaneously, this position facilitates cleaning or replacement of the filter cake through the inspection port on the top of the outer casing 400 or a dedicated slag discharge port without affecting the normal operation of the outlet system below the separator plate 500.

[0084] By adding a filter element 600 above the partition plate 500 in the upper part of the installation chamber, this embodiment achieves centralized pre-filtration of the raw material liquid in the liquid inlet of the multi-cylinder parallel device, effectively eliminating problems such as local blockage, sudden increase in flow resistance, expansion of dead zone in the exchange layer, and rapid decline in exchange efficiency caused by solid impurities in the raw material liquid. Actual operation shows that after the filter element 600 is put into use, the single-cylinder operating cycle can be extended by 1.8 to 4.2 times, the overall chloride ion removal rate of the whole device can be increased by 3% to 11% under the same alkalinity target, the batch fluctuation range of solid alumina content is further compressed to a narrower range, and the production interruption and maintenance costs caused by frequent shutdown for cleaning or replacement of packing are significantly reduced.

[0085] Based on the same technical concept, in a second aspect, the present invention also proposes a process for increasing the basicity and solid alumina content of polyaluminum chloride, using the apparatus of the first aspect, and the process includes the following steps: S100. The filtered polyaluminum chloride salt stock solution is delivered to the dispersion mechanism in a pulse supply manner and dispersed for the first time under the first temperature condition. S200, The solution after initial dispersion is introduced into the first ion exchange unit, and under a second temperature condition lower than the first temperature, it undergoes initial ion exchange through the ion exchange component of the unit and second dispersion through its first dispersion component. S300. The solution that has completed the second dispersion is introduced into the next ion exchange unit, and ion exchange and dispersion treatments are carried out sequentially under a third temperature condition that is lower than the second temperature. S400: The solution flows sequentially through each subsequent ion exchange unit, and the ion exchange and dispersion treatment is repeated in each unit. The treatment temperature decreases according to a preset gradient for each ion exchange unit. S500: The solution, after being processed by the final ion exchange unit, is discharged from the outlet to obtain the finished polyaluminum chloride salt.

[0086] Specifically, after most of the suspended solids in the polyaluminum chloride salt stock solution are removed by the aforementioned filter element 600, it is delivered to the second collection funnel 210 or the open end of the first collection funnel 321 of the uppermost dispersion mechanism 200 in a non-continuous pulse form (pulse period is usually 3-18s, duty cycle 25%-75%) via a pulse supply pump or intermittent metering valve. The first temperature is generally controlled in the range of 70℃-100℃ (preferably 90℃-100℃). At this temperature, the original solution has a lower viscosity and better fluidity, which is conducive to the rapid convergence of the subsequent pulse flow after entering the collection funnel and passing through the mounting hole at a higher instantaneous flow rate, impacting and driving the impeller in the first or second stage dispersion mechanism 200 to generate stable rotation, thereby achieving the initial dispersion. The pulse supply method allows the solution to act on the impeller in the form of a periodic high-velocity liquid jet, avoiding the problem of insufficient impeller speed and dispersion intensity that may occur under continuous low flow. At the same time, the pulse interval allows the impeller to maintain a certain speed by inertia when there is no incoming flow, providing initial shear conditions for the arrival of the next pulse.

[0087] After initial dispersion, the solution falls as fine droplets or thin films into the top inlet zone of the first ion exchange unit 300. It then slowly passes through the ion exchange component 310 (a strongly acidic cation exchange resin or a specially functionalized packing layer) at a second temperature (typically 2°C to 10°C lower than the first temperature, preferably 5°C to 10°C lower). The lower temperature enhances the resin's selective exchange capacity for chloride ions while mitigating the tendency for excessive conversion of hydroxyl complexes in polyaluminum chloride salts towards solid alumina. After the initial ion exchange within the packing layer, the basicity of the solution has improved to some extent, but local concentration gradients and viscosity inhomogeneities may still exist. The solution then falls directly into the first dispersion component 320 of the mechanism (including the second liquid dispersion chamber formed by the first liquid collecting funnel 321, the first rotating shaft 322, the first impeller 323, and the first temperature regulating component 313). Under the combined action of the spiral forced shearing and stretching of the first impeller 323 and the gradual expansion and heat preservation diffusion of the chamber, the second dispersion is completed. The average equivalent diameter of the droplets is usually further reduced to 0.5-2.8 mm, and the uniformity of the concentration field and temperature field is significantly restored.

[0088] The solution, having completed the second dispersion, falls to the top of the next-stage ion exchange unit 300 with a high degree of dispersion and a suitable temperature. The ion exchange and dispersion process is repeated at a third temperature (2℃ to 10℃ lower than the second temperature, preferably 5℃ to 10℃ lower). With each stage of the ion exchange unit 300, the processing temperature decreases according to a preset gradient (typically 4℃ to 12℃ / stage), resulting in a gradual temperature decrease throughout the multi-stage process. This temperature-decreasing strategy continuously enhances the deep exchange capacity of chloride ions on each stage of the resin, effectively suppressing the tendency for excessive solid alumina precipitation that increases with increasing basicity. Simultaneously, combined with efficient dispersion between stages, it maintains a good hydrodynamic state before the solution enters the next stage of the packing layer, avoiding problems such as localized overcooling, rapid viscosity increases, intensified channeling, and expansion of dead zones that easily occur in the later stages of traditional continuous cooling processes.

[0089] The solution flows sequentially through subsequent ion exchange units 300 (usually 3-8 stages, preferably 4-6 stages), with each stage performing a coupled operation of one ion exchange and one dispersion, until the final ion exchange unit 300 discharges the finished solution through its bottom outlet 130. The alkalinity of the finished solution (expressed as the [OH⁻] / [Al] molar ratio) can typically be stably controlled within the range of 2.4-2.75, the chloride ion content is reduced to 0.08%-0.35% (expressed as Cl⁻ mass fraction), and the solid alumina content (expressed as Al₂O₃) can reach 22.5%-26.8%, with significantly reduced batch-to-batch fluctuations.

[0090] In one specific embodiment, a five-stage tandem ion exchange mechanism 300 is configured, with the following temperatures: first temperature 95℃~100℃, second temperature 90℃~95℃, third temperature 80℃~90℃, fourth temperature 70℃~80℃, and fifth temperature 60℃~70℃. The temperature decrease gradient for each stage is controlled within 5℃~10℃, the pulse liquid supply cycle is 8s, and the duty cycle is 45%. After processing, the alkalinity of the finished solution is stabilized at 2.52~2.68, the chloride ion content is 0.12%~0.22%, the solid alumina content is 24.1%~25.6%, and the batch standard deviation is less than 0.8%.

[0091] In another specific embodiment, four stages are set in series, with temperature sequences of 100℃, 90℃, 80℃, and 70℃, a decreasing gradient of 5℃ to 10℃, a pulse period of 12s, a duty cycle of 60%, an alkalinity of 2.45 to 2.62, a chloride ion content of 0.18% to 0.31%, and a solid alumina content of 23.8% to 25.3%.

[0092] By employing a process path involving pulsed liquid supply, multi-stage temperature reduction, and tight coupling of ion exchange and dispersion at each stage, this embodiment effectively solves the technical problems of rapid decline in exchange efficiency, difficulty in accurately controlling alkalinity, excessive precipitation of solid alumina, and poor batch stability in the later stages of traditional polyaluminum chloride salt production. It achieves the unification of deep chloride ion removal and controllable improvement of alkalinity under high solid content conditions, ultimately obtaining polyaluminum chloride salt products with higher basicity, better solid alumina content, and smaller quality fluctuations.

[0093] The above are merely exemplary embodiments of the present invention and are not intended to limit the scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the protection scope of the present invention.

Claims

1. An apparatus for increasing the basicity and solid alumina content of polyaluminum chloride, characterized in that, The application relates to a polyaluminum chloride salt ion exchange device. The device comprises: a mounting cylinder, the inside of which is formed with a vertical mounting channel, the top of the mounting channel being provided with a liquid inlet, and the bottom being provided with a liquid outlet; a dispersion mechanism arranged in the mounting channel close to the liquid inlet, used for dispersing the flowing polyaluminum chloride salt original solution for the first time; a plurality of ion exchange mechanisms, all of which are arranged in the mounting channel in a vertical direction and below the dispersion mechanism, each of the ion exchange mechanisms comprising an ion exchange component and a first dispersion component arranged below the ion exchange component, the ion exchange component being used for ion exchange of the flowing polyaluminum chloride salt original solution under heat preservation, and the first dispersion component being used for re-dispersion of the exchanged solution, a liquid drop chamber being formed between any ion exchange component and the first dispersion component in a vertical direction; the ion exchange components and the first dispersion components in all the ion exchange mechanisms are arranged in a vertical direction in turn and alternately, so that the polyaluminum chloride salt original solution is subjected to a circulation process of ion exchange and re-dispersion in turn until the solution is discharged from the liquid outlet.

2. The apparatus of claim 1, wherein the apparatus is configured to increase the basicity of the polyaluminum chloride and the solid alumina content. The ion exchange component comprises: a first dispersion cover mounted in the mounting channel, the first dispersion cover being arranged in a vertical direction in a gradually expanding manner, a plurality of first flow channels being formed in the first dispersion cover in an array and penetrating the first dispersion cover in a vertical direction; a first temperature adjusting member mounted below the first dispersion cover, a plurality of second flow channels being formed in the first temperature adjusting member in a one-to-one correspondence with the first flow channels, the second flow channels penetrating the first temperature adjusting member in a vertical direction; and a plurality of ion exchange resin columns inserted in a one-to-one correspondence with the second flow channels, the ion exchange resin columns being capable of periodically expanding and shrinking in the corresponding second flow channels.

3. The apparatus of claim 2, wherein the apparatus is configured to increase the basicity of the polyaluminum chloride and the solid alumina content. The first dispersion component comprises: a first liquid collecting funnel mounted in the mounting channel and sealingly connected with the inner wall of the mounting cylinder, the bottom of the first liquid collecting funnel being formed with a first mounting hole; a first rotating shaft rod rotatably mounted in the first mounting hole through a support and extending downward out of the first mounting hole in a vertical direction; at least two first paddles distributed in a circumferential direction on the outer periphery of the first rotating shaft rod and exposed to the outside of the first mounting hole; and a second temperature adjusting member formed with a first liquid dispersion chamber penetrating in a vertical direction, the first liquid dispersion chamber being arranged in a gradually expanding manner downward in a vertical direction, the second temperature adjusting member being mounted below the first liquid collecting funnel, and the first paddles being accommodated in the first liquid dispersion chamber; the first paddles being capable of rotating and dispersing the polyaluminum chloride salt original solution under the washing action of the polyaluminum chloride salt original solution flowing into the first mounting hole through the first liquid collecting funnel.

4. The apparatus of claim 3, wherein the apparatus is configured to increase the basicity of the polyaluminum chloride and the solid alumina content. The first paddles are arranged in a spiral manner in a vertical direction.

5. The apparatus of claim 3, wherein the apparatus is configured to increase the basicity of the polyaluminum chloride and the solid alumina content. The first dispersing member further comprises a second dispersing cover, which is installed on the top of the first rotating shaft rod, is located in the first collecting funnel, and has a structure of gradually expanding first and then gradually shrinking in the vertical direction.

6. The apparatus for increasing the basicity and solid alumina content of the polyaluminum chloride of any one of claims 1 to 5, wherein, The dispersing mechanism comprises: a second collecting funnel, which is installed in the installation channel and is in sealing connection with the inner wall of the installation cylinder, and has a second installation hole formed at the bottom thereof; a second rotating shaft rod, which is rotatably installed in the second installation hole through a support and extends out of the second installation hole in the vertical direction; at least two second paddles, which are distributed on the outer periphery of the second rotating shaft rod in the circumferential direction and are exposed to the second installation hole, and are arranged in the vertical direction in a spiral manner; and a third temperature adjusting member, which has a second liquid dispersing chamber penetratingly formed therein in the vertical direction, is arranged in the vertical direction in a gradually expanding manner, is installed below the second collecting funnel, and accommodates the second paddles in the second liquid dispersing chamber. The second paddles can rotate and disperse the raw solution of the aluminum chloride salt under the washing action of the raw solution of the aluminum chloride salt flowing into the second installation hole through the second collecting funnel.

7. The apparatus of claim 6 wherein the apparatus is configured to increase the basicity of the polyaluminum chloride and the solid alumina content. The dispersing mechanism further comprises a third dispersing cover, which is installed on the top of the second rotating shaft rod, is located in the second collecting funnel, and has a structure of gradually expanding first and then gradually shrinking in the vertical direction.

8. The apparatus for increasing the basicity and solid alumina content of the polyaluminum chloride of any one of claims 1 to 5, wherein, Further comprising a housing and a separation plate, the housing has an installation cavity formed therein, the separation plate is installed in the installation cavity, and the separation plate divides the installation cavity into a plurality of placement through holes arranged in an array, the placement through holes are consistent in number with the installation cylinders and one-to-one correspondingly install one installation cylinder.

9. The apparatus of claim 8 wherein the apparatus is configured to increase the basicity of the polyaluminum chloride and the solid alumina content. Further comprising a filter, which is installed in the installation cavity and is located above the separation plate.

10. A process for increasing the basicity and solid alumina content of a polyaluminum chloride, characterized in that, The device according to any one of claims 1 to 9 is applied, and the process comprises the following steps: The filtered raw solution of the aluminum chloride salt is delivered to the dispersing mechanism in a pulse liquid supply mode, and is subjected to first dispersion under a first temperature condition; The solution after the first dispersion is introduced into the first ion exchange mechanism, is subjected to first ion exchange through the ion exchange members of the mechanism and second dispersion through the first dispersing members of the mechanism in sequence under a second temperature condition lower than the first temperature; The solution after the second dispersion is introduced into the next ion exchange mechanism, is subjected to ion exchange and dispersion treatment in sequence under a third temperature condition lower than the second temperature; The solution is sequentially introduced into the subsequent ion exchange mechanisms, and is subjected to ion exchange and dispersion treatment in sequence in each mechanism, wherein the treatment temperature is decreased by a preset gradient compared with the previous mechanism after each ion exchange mechanism; The solution after the treatment of the last ion exchange mechanism is discharged from the liquid outlet, and the finished product of the aluminum chloride salt is obtained.

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