Fluorine-containing wastewater resource recovery treatment equipment for photovoltaic industry

Abstract

The invention relates to the technical field of wastewater resource recovery and treatment, and discloses photovoltaic industry fluorine-containing wastewater resource recovery and treatment equipment which comprises a quality-divided pretreatment module, an acid-base coupling reaction module and a deep purification and recovery module which are communicated in sequence, the quality-divided pretreatment module comprises a concentrated acid wastewater pretreatment unit and a concentrated alkali wastewater pretreatment unit which are arranged in parallel and are respectively used for pretreating concentrated acid fluorine-containing wastewater and concentrated alkali silicon-containing wastewater generated in the photovoltaic industry; according to the photovoltaic industry fluorine-containing wastewater resource recovery treatment equipment, fluorine ions in wastewater and a calcium source are directionally combined to form calcium fluoride crystal particles through an induced crystallization technology of an acid-base coupling reaction module, and the influence of interference ions such as silicon and calcium is effectively avoided by combining with precise removal of impurities through quality-divided pretreatment, so that the purity of recovered calcium fluoride is greatly improved; and the alkali liquor recycling unit is used for refining alkali resources in the treated liquid through gravity settling, layered drainage and accurate concentration regulation and control.

Description

Technical Field

[0001] This invention relates to the field of wastewater resource recycling and treatment technology, specifically to a device for recycling and treating fluoride-containing wastewater from the photovoltaic industry. Background Technology

[0002] In the global energy transition towards clean energy, the photovoltaic industry, as a core pillar of renewable energy, has witnessed large-scale expansion and technological upgrades. However, the photovoltaic module production process (especially key processes such as silicon wafer etching, texturing, and cleaning) generates a large amount of fluoride-containing and silicon-containing wastewater. This type of wastewater is characterized by complex composition, high pollutant concentration, and strong acid and alkali corrosivity. Concentrated acidic fluoride-containing wastewater has a fluoride ion concentration of 1000-5000 mg / L, a pH value ≤2, and contains solid impurities such as silicon powder and metal oxides; concentrated alkaline silicon-containing wastewater has a silicon concentration of 500-1500 mg / L, a pH value ≥12, and is accompanied by interfering ions such as calcium ions. Direct discharge of these wastewaters would not only cause serious water pollution and soil fluoride accumulation, but also lead to the waste of valuable resources such as fluoride and alkali, which contradicts the "green and low-carbon" development concept of the photovoltaic industry.

[0003] Currently, the photovoltaic industry faces numerous technical bottlenecks in the treatment of fluoride-containing wastewater, which restrict resource recovery efficiency and environmental compliance levels. Low purity of fluorine resource recovery: Traditional treatment processes mostly use direct chemical precipitation, which involves adding calcium salts to generate calcium fluoride precipitate from fluoride ions. However, interfering ions such as silicon and calcium in the wastewater are prone to forming complex impurities with fluoride ions, resulting in the purity of calcium fluoride products reaching only 70%-85%, which cannot meet the requirements for industrial raw material reuse and can only be disposed of as solid waste, wasting resources and increasing environmental pressure. Serious waste of alkali resources: Most of the alkali in concentrated alkali silicon wastewater is neutralized and consumed during the treatment process or discharged with the wastewater. Existing technologies lack targeted alkali resource refining and recovery systems, resulting in huge consumption of fresh alkali reagents during photovoltaic production, which significantly increases the operating costs of enterprises. Insufficient control of impurities: Existing pretreatment processes mostly use single filtration or simple neutralization, which makes it difficult to accurately remove solid impurities, soluble silicon, calcium ions and other interfering components from wastewater. After these impurities enter the subsequent reaction system, they can easily cause problems such as equipment blockage, seed contamination and reduced reaction efficiency, affecting the stability of the overall treatment effect. Low level of automation and integration: Existing treatment equipment is mostly distributed, with a lack of coordination between units. Adsorption resin needs to be replaced and regenerated after shutdown. Acid and alkali addition and adsorption mode switching rely on manual operation. This not only occupies a lot of space and consumes a lot of energy, but also poses a risk of fluctuation in effluent water quality due to human operation errors. It is difficult to adapt to the needs of large-scale and continuous production in the photovoltaic industry.

[0004] Therefore, developing a fluoride-containing wastewater treatment device that can achieve efficient recovery of fluoride and alkali resources, precise removal of impurities and interference, and a high degree of automation has become a key technical problem that urgently needs to be solved in the process of green and sustainable development of the photovoltaic industry. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a fluoride-containing wastewater recycling and treatment device for the photovoltaic industry, thereby solving the problems of low fluoride recovery purity, waste of alkali resources, serious impurity interference, and low automation in the prior art.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a photovoltaic industry fluoride-containing wastewater resource recovery and treatment device, comprising: The components are sequentially connected: a pretreatment module, an acid-base coupling reaction module, and a deep purification and recovery module. The pretreatment module includes a concentrated acid wastewater pretreatment unit and a concentrated alkali wastewater pretreatment unit arranged in parallel, which are used to pretreat concentrated acid fluoride wastewater and concentrated alkali silicon wastewater generated in the photovoltaic industry, respectively. The acid-base coupling reaction module is an induced crystallization fluidized bed reactor, used to receive the pretreated wastewater output from the fractional pretreatment module, and realize the particle-based recovery of fluoride ions and the synergistic treatment of acid and base. The deep purification and recovery module includes a treatment tower and a resin adsorption unit and an alkali reuse unit disposed inside the treatment tower. The resin adsorption unit and the alkali reuse unit are connected in sequence from top to bottom. The resin adsorption unit is used to adsorb and remove residual fluoride ions from the liquid output by the acid-base coupling reaction module. The alkali reuse unit is used to classify, store and reuse the liquid after the removal of residual fluoride ions.

[0007] Preferably, the concentrated acid wastewater pretreatment unit includes a first filtration chamber and an acid buffer chamber connected in sequence; The first filtration chamber is equipped with a detachable ceramic filter plate for removing solid impurities from wastewater. The bottom of the acid buffer chamber is equipped with a pH sensor and a temperature sensor for real-time monitoring of water quality parameters. The acid buffer chamber is electrically connected to the intelligent control unit, which regulates the pH value of the acid entering the subsequent units.

[0008] Preferably, the concentrated alkaline wastewater pretreatment unit includes a second filtration chamber, a silicon removal reaction chamber, and a calcium removal adsorption chamber connected in sequence; The second filtration chamber is equipped with a stainless steel filter screen for removing large particulate impurities; The silicon removal reaction chamber is equipped with a stirring assembly and a calcium hydroxide dosing port, and the inner wall of the chamber is equipped with a heating jacket for regulating the reaction temperature. The calcium removal adsorption chamber is filled with a highly selective chelating resin layer for selectively adsorbing calcium ions, and filter support structures are provided at both ends of the resin layer. The calcium removal adsorption chamber is provided with a regenerant injection port.

[0009] Preferably, the reactor body of the acid-base coupling reaction module is provided with a clear water zone, a separation zone, a granulation zone, a sedimentation zone and a neutralization reaction precipitation zone from top to bottom; The granulation zone is provided with a seed inlet and an internal reflux channel on its sidewall. The internal reflux channel is connected to the neutralization reaction precipitation zone at the bottom of the reactor body. The neutralization reaction precipitation zone is connected to the outlet of the acid buffer chamber of the concentrated acid wastewater pretreatment unit and the calcium removal adsorption chamber of the concentrated alkali wastewater pretreatment unit through pipelines, and the pipelines are equipped with flow control valves. The bottom of the settling zone is provided with a conical discharge port for discharging calcium fluoride particles, and the separation zone is provided with an overflow port for discharging clean water.

[0010] Preferably, the resin adsorption unit includes an adsorption cylinder, several auxiliary cylinders, a diversion pipe, a backwashing assembly, and a rotary motor assembly; The adsorption cylinder and several auxiliary cylinders are all located inside the treatment tower and are all filled with defluorination resin. The adsorption cylinder is located between several auxiliary cylinders. The diversion pipe is used to selectively connect the adsorption cylinder to one or two auxiliary cylinders to form single-cylinder adsorption or multi-cylinder adsorption. The rotary motor assembly is connected to several auxiliary cylinders for driving the auxiliary cylinders to move in a circular motion around the adsorption cylinder as the axis, thereby switching the position of the standby auxiliary cylinder. The backwashing assembly is used to restore the defluorination resin inside the spare auxiliary cylinder.

[0011] Preferably, the bottom of the auxiliary cylinder is provided with a water filtration area, the inside of the auxiliary cylinder is equipped with a discharge pipe, the outer surface of the discharge pipe is provided with a discharge port, and the discharge port is provided with a filter membrane. The outlet end of the diversion pipe is connected to the bottom end of the outlet pipe, which is used to selectively discharge the liquid treated inside the adsorption cylinder into the outlet pipe, and then discharge it through the outlet port on the outlet pipe to achieve secondary fluoride ion adsorption.

[0012] Preferably, the diversion fitting includes a diversion pipe, an annular sealing plate, and a pressure blocking structure; The diversion pipe is located inside the treatment tower and can be connected to one or two outlet pipes. The diversion pipe is connected to the outlet end of the adsorption cylinder. The outlet end of the adsorption cylinder is provided with several horizontally arranged filter ports. The annular sealing plate and the pressure blocking structure are located inside the outlet end and are fixed together by a connecting rod. When the pressure of the liquid discharged from the adsorption cylinder exceeds the preset threshold, the blocking end of the pressure blocking structure opens, and the connecting rod drives the annular sealing plate to move down to seal and block the filter outlet, so that the liquid discharged from the adsorption cylinder enters the auxiliary cylinder through the diversion pipe for secondary adsorption.

[0013] Preferably, the backwash assembly includes a backwash pipe and a discharge pipe rack; The water injection end of the backwash pipe is connected to the bottom end of one or two outlet pipes, which is used to inject the backwash medium into the outlet pipe to restore the defluorination resin inside the auxiliary cylinder. One or two sludge collection hoods are fixedly connected to the discharge pipe rack. The sludge collection hoods are located directly below the spare auxiliary cylinder and are used to receive backwash wastewater from inside the spare auxiliary cylinder. The outlet tube is installed inside the auxiliary cylinder by rotation. The outlet tube has several groups of outlets, which are equidistantly arranged along the axis of the outlet tube. The uppermost outlet is the adsorption outlet, and the rest are rinsing outlets. The inner top of the auxiliary cylinder is fixed with a fixed shaft, and a number of baffles for sealing and blocking the flushing inlet are fixedly connected to the outer surface of the fixed shaft. A gear is fixed to the outer surface of the bottom end of the outlet tube, and an arc-shaped gear frame is fixedly connected to the inner surface of the processing tower. The arc-shaped gear frame meshes with the gear and is used to drive the outlet tube, which is in ring motion, to rotate.

[0014] Preferably, the alkali recycling unit includes a processing buffer zone and a refined product zone; The processing buffer zone is cone-shaped, with a sedimentation area at the bottom and a slag discharge pipe installed at the bottom to remove residual resin debris and suspended matter from the alkaline solution by gravity sedimentation. An automatic slag discharge valve is installed on the slag discharge pipe. A drainage unit is installed on the processing buffer. The drainage unit includes a conical ring plate and a waterproof drive component for rotating the conical ring plate. A drainage port A is provided on the processing buffer. The conical ring plate is tightly fitted to the top of the processing buffer, and a connecting port B is provided on the side of the conical ring plate. The connecting port B and the drainage port A partially overlap to form an overlapping port C. The liquid that has settled inside the processing buffer is drained to the premium area through the overlapping port C. The bottom of the premium area is fixedly connected to an alkali recovery pipe, which is equipped with an online alkali concentration detector and a mixing tube. The online alkali concentration detector is used to detect the alkali concentration, and an appropriate amount of clean water or concentrated alkali is added through the mixing tube to adjust the alkali concentration to the standard range suitable for the photovoltaic etching process.

[0015] Preferably, the drain port A is vortex-shaped, and a filter membrane for isolating resin debris and suspended matter is provided inside the drain port A; the overlapping port B is a cone-shaped structure that is wider at the top and narrower at the bottom.

[0016] (III) Beneficial Effects Compared with the prior art, the present invention provides a fluoride-containing wastewater resource recovery and treatment device for the photovoltaic industry, which has the following beneficial effects: This invention enables highly efficient fluorine resource recovery with superior purity and utilization rate: through the induced crystallization technology of the acid-base coupling reaction module, fluoride ions in wastewater are directionally combined with calcium sources to form calcium fluoride crystal particles. Combined with the precise removal of impurities by fractional pretreatment, the influence of interfering ions such as silicon and calcium is effectively avoided. The recovered calcium fluoride can reach a purity of over 95% and can be directly reused as an industrial raw material. This realizes the transformation of fluorine resources from "wastewater pollutants" to "usable resources" and greatly enhances the resource recovery value.

[0017] This invention enables the recycling of alkali resources, reducing production costs: The alkali reuse unit of the deep purification and recovery module refines the alkali resources in the treated liquid through gravity sedimentation, stratified diversion, and precise concentration control. This not only removes impurities such as residual resin debris and suspended solids, but also adjusts the alkali concentration to a standard range suitable for photovoltaic etching processes through an online concentration detection and blending system. This achieves the recycling of alkali resources, significantly reducing the consumption of fresh alkali reagents in photovoltaic production, and lowering enterprise operating costs and raw material losses.

[0018] This invention features a compact structure and optimized space and energy consumption: the deep purification and recovery module adopts an integrated layout within the tower, with the resin adsorption unit and alkali reuse unit arranged in layers from top to bottom, and auxiliary cylinders arranged around the adsorption cylinder to form a compact spatial structure, significantly improving space utilization; the acid-base coupling reaction module realizes the recycling of reaction liquid through an internal reflux channel, reducing reagent consumption and energy consumption; the backwashing component realizes online resin regeneration, avoiding resource waste and increased energy consumption caused by frequent resin replacement, and the overall process is both highly efficient and economical. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment of the present invention; Figure 2 This is a rear view of the structure of the photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment of the present invention; Figure 3 (a) is an external view of the deep purification and recycling module of the present invention; Figure 3 (b) is an internal diagram of the deep purification and recycling module of the present invention; Figure 4 For the present invention Figure 3 A magnified view of a portion of point Q; Figure 5 (a) is a combination diagram of the processing buffer of the present invention; Figure 5 (b) is a combined top view of the processing buffer of the present invention; Figure 5 (c) is a breakdown diagram of the processing buffer of this invention; Figure 6 This is a schematic diagram of the structure of the resin adsorption unit of the present invention; Figure 7 This is a cross-sectional schematic diagram of the resin adsorption unit of the present invention; Figure 8 This is a schematic diagram illustrating the rotation principle of the auxiliary cylinder of the present invention.

[0020] In the diagram: 100, pretreatment module for different types of wastewater; 110, pretreatment unit for concentrated acid wastewater; 120, pretreatment unit for concentrated alkali wastewater. 200. Acid-base coupling reaction module; 300. Deep purification and recovery module; 310. Resin adsorption unit; 311. Adsorption cylinder; 312, Auxiliary cylinder; 3121, Outlet tube; 3122, Outlet port; 3123, Baffle frame; 313. Diversion fitting; 3131. Diversion pipe; 3132. Annular sealing plate; 3133. Pressure plugging structure; 314. Backwash assembly; 3141. Backwash pipe; 3142. Discharge pipe rack; 3143. Gear; 3144. Arc-shaped gear rack; 315. Rotary motor assembly; 320. Alkali reuse unit; 321. Processing buffer zone; 3211. Conical ring plate; 3212. Waterproof drive unit; 322. Premium area; 3221. Alkali recovery pipe; 3222. Online alkali concentration detector. Detailed Implementation

[0021] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: See attached document Figures 1 to 8A photovoltaic industry fluoride-containing wastewater resource recovery and treatment device includes: a fractional pretreatment module 100, an acid-base coupling reaction module 200, and a deep purification and recovery module 300 connected in sequence; the fractional pretreatment module 100 includes a concentrated acid wastewater pretreatment unit 110 and a concentrated alkali wastewater pretreatment unit 120 arranged in parallel, which are used to pretreat concentrated acid fluoride-containing wastewater and concentrated alkali silicon-containing wastewater generated in the photovoltaic industry, respectively; the acid-base coupling reaction module 200 is an induced crystallization fluidized bed reactor, which is used to receive the pretreated wastewater output from the fractional pretreatment module 100 to realize the particulate recovery of fluoride ions and the synergistic treatment of acid and alkali; The equipment adopts a three-stage series process architecture of "pretreatment-coupling reaction-deep purification and recovery", which meets the core requirements of the photovoltaic industry for "differentiated treatment, resource recovery, and compliant reuse" of fluoride-containing wastewater. The differentiated pretreatment module 100 adopts a parallel dual-unit design to achieve targeted pretreatment for the water quality differences between concentrated acidic fluoride-containing wastewater (mostly from silicon wafer etching and cleaning processes, with fluoride concentration of 1000-5000 mg / L and pH≤2) and concentrated alkaline silicon-containing wastewater (originating from silicon material cleaning and texturing processes, with silicon concentration of 500-1500 mg / L and pH≥12) in photovoltaic production. This avoids reaction disorder and impurity accumulation caused by direct mixing of wastewater with different properties. The acid-base coupling reaction module 200 uses an induced crystallization fluidized bed reactor. Its core principle is to use induced crystallization technology to combine fluoride ions with calcium source to form calcium fluoride crystal particles under specific reaction conditions. At the same time, through the synergistic neutralization reaction of acid and alkali wastewater, the consumption of acid and alkali reagents in the system is reduced, and the granular recovery of fluoride resources is realized (the purity of calcium fluoride can reach more than 95%, which can be reused as an industrial raw material).

[0023] The deep purification and recovery module 300 includes a treatment tower and a resin adsorption unit 310 and an alkali reuse unit 320 disposed inside the treatment tower. The resin adsorption unit 310 and the alkali reuse unit 320 are connected sequentially from top to bottom. The resin adsorption unit 310 is used to adsorb and remove residual fluoride ions from the liquid output by the acid-base coupling reaction module 200. The alkali reuse unit 320 is used to classify, store and reuse the liquid after the removal of residual fluoride ions.

[0024] The deep purification and recovery module 300 adopts an integrated dual-unit design within the tower. The resin adsorption unit 310 and the alkali reuse unit 320 are arranged in layers from top to bottom, forming a continuous process of "residual fluoride removal - alkali purification and reuse". The resin adsorption unit 310 deeply removes trace fluoride ions from the water through the physicochemical adsorption of specific defluorinating resin (the fluoride concentration after treatment is ≤1mg / L, which meets the Class A standard of "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" GB18918-2002). The alkali reuse unit 320, through water purification and concentration control, enables the recovered alkali to meet the reuse requirements of the photovoltaic etching process, realizing the recycling of alkali resources and reducing production costs.

[0025] See attached document Figures 1 to 2 The concentrated acid wastewater pretreatment unit 110 includes a first filtration chamber and an acid buffer chamber connected in sequence. The first filtration chamber is equipped with a detachable ceramic filter plate for removing solid impurities from the wastewater. The bottom of the acid buffer chamber is equipped with a pH sensor and a temperature sensor for real-time monitoring of water quality parameters. The acid buffer chamber is electrically connected to an intelligent control unit, which regulates the pH value of the acid entering the subsequent units.

[0026] The concentrated acid wastewater pretreatment unit 110 adopts a two-stage treatment structure of "filtration-buffering and regulation". Its core design is to ensure the stability of the feed water quality for subsequent acid-base coupling reactions.

[0027] The first filtration chamber serves as the pretreatment head and is equipped with a removable ceramic filter plate. The ceramic filter plate is made of porous ceramic material with a pore size of 5-10μm. It has the characteristics of high temperature resistance, strong acid corrosion resistance, and high mechanical strength. Its working principle is to remove suspended solid impurities (such as silicon powder, metal oxide particles, etc. with a particle size ≥5μm) in concentrated acid wastewater through physical interception effect, so as to avoid impurities entering the subsequent reaction system and causing problems such as equipment blockage and seed contamination.

[0028] The detachable design facilitates the cleaning and replacement of the filter plates, ensuring long-term stability of filtration efficiency. The acid buffer chamber, as a water quality control unit, has the core function of precisely pre-adjusting the pH value of the acid solution and real-time monitoring of water quality parameters.

[0029] The pH sensor (measurement range 0-14, accuracy ±0.01pH) and temperature sensor (measurement range 0-100℃, accuracy ±0.1℃) installed inside the chamber can collect the pH value and temperature data of the acid solution in real time and transmit them to the intelligent control unit (PLC-based automatic control system).

[0030] The intelligent control unit adjusts the discharge flow rate of the acid buffer chamber or adds an appropriate amount of neutralizing agent by preset process parameter thresholds to adjust the pH value of the acid solution to a suitable range of 3-4, providing stable feeding conditions for the subsequent acid-base coupling reaction and avoiding the decrease in calcium fluoride crystallization efficiency or incomplete reaction due to excessive fluctuations in the pH value of the acid solution.

[0031] See attached document Figures 1 to 2 The concentrated alkaline wastewater pretreatment unit 120 includes a second filtration chamber, a silicon removal reaction chamber, and a calcium removal adsorption chamber connected in sequence. The second filtration chamber is equipped with a stainless steel filter screen for removing large particulate impurities. The silicon removal reaction chamber is equipped with a stirring assembly and a calcium hydroxide dosing port. The inner wall of the chamber is equipped with a heating jacket for regulating the reaction temperature. The calcium removal adsorption chamber is filled with a highly selective chelating resin layer for selectively adsorbing calcium ions. The resin layer is equipped with filter screen support structures at both ends. The calcium removal adsorption chamber is equipped with a regenerant dosing port.

[0032] The concentrated alkaline wastewater pretreatment unit 120 adopts a "three-stage progressive" treatment structure to remove the core pollutants (large particulate impurities, soluble silicon, and calcium ions) of the concentrated alkaline silicon-containing wastewater in stages, ensuring the efficient execution of subsequent coupling reactions.

[0033] The second filtration chamber has a built-in stainless steel filter screen (made of 316L stainless steel, with a pore size of 10-20μm). Its working principle is to remove large particulate impurities (such as silicon material debris, equipment corrosion products, etc.) from the wastewater through mechanical sieving effect, so as to prevent impurities from entering the subsequent chambers and causing pipeline blockage or reduced reaction efficiency.

[0034] The silicon removal reaction chamber is the core unit of the pretreatment. Its working principle is to add calcium hydroxide (as a silicon removal agent) to the concentrated alkaline wastewater. Under heating and stirring conditions, the calcium hydroxide reacts chemically with the soluble silicon in the wastewater (mainly in the form of silicate ions) to generate insoluble calcium silicate precipitate (reaction equation: Ca(OH)2+Na2SiO3=CaSiO3↓+2NaOH).

[0035] The stirring components inside the chamber (using a paddle stirrer with a stirring speed of 50-100 r / min) can ensure uniform mixing of the reaction system and improve the reaction rate; the heating jacket (using electric heating with a temperature control range of 40-60℃) optimizes the formation conditions of calcium silicate precipitate by regulating the reaction temperature, thereby improving the silicon removal efficiency (the silicon removal rate can reach over 90%).

[0036] The core function of the calcium removal adsorption chamber is to remove calcium ions from wastewater, preventing them from reacting prematurely with fluoride ions in the acid-base coupling reaction module 200 to form fine calcium fluoride precipitates, which would affect the granular recovery effect. The chamber is filled with a highly selective chelating resin (such as aminophosphonic acid chelating resin), which works by using specific functional groups (such as phosphonic acid groups) on the resin molecular chain to specifically chelate with calcium ions, achieving selective adsorption of calcium ions (adsorption capacity can reach 0.5-1.0 mmol / g).

[0037] The filter support structures (made of polypropylene, 5μm pore size) at both ends of the resin layer prevent resin particle loss and ensure uniform wastewater flow through the resin layer. The regenerant inlet is used to periodically inject regenerant (such as hydrochloric acid solution) into the chamber, restoring the adsorption performance of the chelating resin through ion exchange reaction, thus enabling the resin to be recycled. See attached document Figures 1 to 2The reactor body of the acid-base coupling reaction module 200 is provided with a clear water zone, a separation zone, a granulation zone, a sedimentation zone, and a neutralization reaction sedimentation zone from top to bottom. The side wall of the granulation zone is provided with a seed crystal addition port and an internal reflux channel, which is connected to the neutralization reaction sedimentation zone at the bottom of the reactor body. The neutralization reaction sedimentation zone is connected to the outlet of the acid buffer chamber of the concentrated acid wastewater pretreatment unit 110 and the calcium removal adsorption chamber of the concentrated alkali wastewater pretreatment unit 120 through pipelines, and the pipelines are provided with flow control valves. The bottom of the sedimentation zone is provided with a conical discharge port for discharging calcium fluoride particles, and the separation zone is provided with an overflow port for discharging clear water.

[0038] The reactor body of the acid-base coupling reaction module 200 adopts a layered structure design, with each area having a clearly defined function and working in synergy. Its core principle is to combine induced crystallization technology with acid-base neutralization reaction to achieve efficient recovery of fluoride ions and preliminary purification of wastewater. From top to bottom, the clear water zone, separation zone, granulation zone, sedimentation zone, and neutralization reaction sedimentation zone form a continuous process of "reaction-crystallization-separation".

[0039] The neutralization reaction precipitation zone serves as the initial reaction area, receiving pretreated concentrated acid wastewater and concentrated alkali wastewater through pipelines. The flow control valves on the pipelines (using electromagnetic flow control valves with a control accuracy of ±1%) can adjust the feed ratio of the two types of wastewater according to the instructions of the intelligent control unit, so that the acid and alkali wastewater undergo a neutralization reaction in this zone, and adjust the pH value of the system to the suitable range for calcium fluoride crystallization (pH=6-8).

[0040] The granulation zone is the core area for calcium fluoride crystallization. The seed inlet on the side wall is used to add calcium fluoride seed crystals (50-100μm in diameter) into the cavity. Through seed induction, fluoride ions and calcium ions in the solution grow directionally on the seed surface to form large calcium fluoride crystals (avoiding the formation of small precipitates that are difficult to separate). The internal reflux channel returns part of the mixed liquid from the neutralization reaction precipitation zone to the granulation zone. On the one hand, this increases the liquid turbulence in the granulation zone, promotes full contact between the seed crystals and ions, and on the other hand, it maintains the stability of the liquid level in the granulation zone, optimizing the crystallization environment.

[0041] The settling zone utilizes the principle of gravity settling, causing the generated calcium fluoride particles (density 3.18 g / cm³) to settle. 3 The particles settle rapidly in this area, and the conical discharge port at the bottom (cone angle 60°) facilitates the concentrated discharge of the particles. The discharged calcium fluoride particles can be washed and dried and reused as industrial raw materials.

[0042] The separation zone achieves solid-liquid separation through overflow. The supernatant after sedimentation (fluoride concentration reduced to 50-100 mg / L) is discharged from the overflow port and enters the subsequent deep purification and recovery module 300. The clear water zone is located at the top of the reactor and plays a role in buffering and stabilizing the overflow, avoiding a decrease in separation effect due to liquid level fluctuations.

[0043] See attached document Figure 3 (a, b) Figure 4 and Figures 6 to 8 The resin adsorption unit 310 includes an adsorption cylinder 311, several auxiliary cylinders 312, a diversion pipe 313, a backwashing assembly 314, and a rotary motor assembly 315. The resin adsorption unit 310 adopts a modular design of "main cylinder + multiple auxiliary cylinders 312". Its core function is to deeply remove residual fluoride ions from wastewater after acid-base coupling reaction, ensuring that the fluoride concentration of the effluent meets the standards.

[0044] The adsorption cylinder 311 and several auxiliary cylinders 312 are all located inside the treatment tower and are all filled with defluorination resin. The adsorption cylinder 311 is located between the auxiliary cylinders 312. The adsorption cylinder 311 serves as the main adsorption unit, and the auxiliary cylinders 312 serve as backup / secondary adsorption units. Both are filled with high-efficiency defluorination resin (such as hydroxyapatite-type defluorination resin, alumina-modified resin, etc., with an adsorption capacity of ≥1.5mg / g for fluoride ions and an adsorption accuracy of less than 0.1mg / L). The adsorption cylinder 311 is located in the center, and the auxiliary cylinders 312 are arranged around it to form a compact spatial layout, thereby improving the space utilization of the treatment tower.

[0045] The diversion fitting 313 is used to selectively connect the adsorption cylinder 311 to one or two auxiliary cylinders 312 to form single-cylinder adsorption or multi-cylinder adsorption. As the core component for fluid distribution, the diversion fitting 313 is designed to selectively connect the adsorption cylinder 311 and the auxiliary cylinders 312 through valve switching. It can flexibly switch between single-cylinder adsorption or multi-cylinder adsorption modes according to the influent fluoride concentration and treatment volume: when the influent fluoride concentration is low (50-100mg / L), the single-cylinder adsorption mode (only the adsorption cylinder 311 works) can meet the treatment requirements; when the influent fluoride concentration is high or the treatment volume is large, it switches to multi-cylinder adsorption mode (the adsorption cylinder 311 works in series or parallel with 1-2 auxiliary cylinders 312) to improve adsorption treatment efficiency and ensure stable effluent quality.

[0046] The rotary motor assembly 315 is connected to several auxiliary cylinders 312 for driving them to move in a circular motion around the adsorption cylinder 311, thus switching the position of the standby auxiliary cylinder 312. The rotary motor assembly 315 (using a stepper motor with a positioning accuracy of ±0.5°) drives the auxiliary cylinders 312 to move in a circular motion around the adsorption cylinder 311 via gear 3143, enabling rapid switching between the standby and working auxiliary cylinders 312, avoiding equipment downtime due to resin regeneration, and ensuring the continuity of the processing. The backwash assembly 314 is used to restore the defluorination resin inside the spare auxiliary cylinder 312. The core function of the backwash assembly 314 is to realize the online regeneration of the defluorination resin. Its principle is to reverse the flow of a regeneration medium (such as dilute hydrochloric acid or sodium hydroxide solution) to cause the saturated defluorination resin to undergo a desorption reaction, release the adsorbed fluoride ions, and restore the adsorption performance of the resin. This assembly works in conjunction with the rotary motor unit 315. When the resin adsorption of a certain auxiliary cylinder 312 is saturated, the rotary motor unit 315 switches it to the standby position, and then the backwash assembly 314 performs regeneration treatment to realize the recycling of resin and reduce operating costs.

[0047] See attached document Figure 7 and Figure 8 The bottom of the auxiliary cylinder 312 is provided with a water filtration area for exporting the liquid that has undergone secondary adsorption into the processing buffer 321. An export pipe 3121 is installed inside the auxiliary cylinder 312, and an export port 3122 is opened on the outer surface of the export pipe 3121. A filter membrane is provided inside the export port 3122. As a key component of the resin adsorption unit 310, the auxiliary cylinder 312 combines secondary adsorption and fluid discharge functions. Its structural design revolves around "enhancing adsorption effect and ensuring fluid uniformity." The bottom filtration zone adopts a porous filter plate structure (pore size 1-2μm), which performs preliminary filtration on the liquid after secondary adsorption, removing any resin particles that may be entrained, and preventing them from entering the treatment buffer zone 321 and causing pipeline blockage or affecting subsequent alkaline purification. The internally installed discharge pipe 3121 is the core component for fluid guidance. The discharge ports 3122 (uniformly arranged along the axis of the discharge pipe 3121, 4-6 sets) on its outer surface are used to uniformly discharge the liquid discharged from the adsorption cylinder 311 into the resin layer of the auxiliary cylinder 312. The filter membrane (made of polytetrafluoroethylene, pore size 0.45μm) installed inside the discharge port 3122 can further trap tiny impurities in the liquid, while preventing defluorination resin particles in the auxiliary cylinder 312 from entering the discharge pipe 3121 and causing blockage.

[0048] The outlet end of the diversion fitting 313 is connected to the bottom end of the outlet pipe 3121, which is used to selectively discharge the liquid treated inside the adsorption cylinder 311 into the outlet pipe 3121, and then discharge it through the outlet port 3122 on the outlet pipe 3121 to achieve secondary fluoride ion adsorption.

[0049] The outlet end of the diversion fitting 313 and the bottom end of the outlet pipe 3121 are connected by a sealed contact (the sealing method is O-ring sealing, resistant to acid and alkali corrosion). Through the overlapping contact of the diversion fitting 313 and the outlet pipe 3121, and the compression of the O-ring during the contact process, a sealed connection is formed. The outlet pipe 3121 and the backwash pipe 3141 are connected in the same way. The liquid (fluoride concentration 50-100 mg / L) treated by the adsorption cartridge 311 can be selectively introduced into the outlet pipes 3121 of 1-2 auxiliary cartridges 312. The liquid is evenly dispersed into the defluorination resin layer of the auxiliary cartridge 312 through the outlet port 3122 for secondary adsorption treatment. The principle of secondary adsorption is to use the specific adsorption effect of the defluorination resin on fluoride ions to further remove residual fluoride ions in the liquid, so that the fluoride concentration of the treated liquid is reduced to below 1 mg / L, which meets the requirements of deep purification. At the same time, the design of multiple outlets 3122 ensures sufficient contact between the liquid and the resin layer, improves the adsorption efficiency and adsorption uniformity, and avoids local adsorption saturation.

[0050] See attached document Figure 3 (a, b) Figure 4 , Figure 6 and Figure 7 The diversion fitting 313 includes a diversion pipe 3131, an annular sealing plate 3132, and a pressure blocking structure 3133. The diversion pipe 3131 is located inside the treatment tower and can be connected to one or two outlet pipes 3121. The diversion pipe 3131 is connected to the outlet end of the adsorption cylinder 311. The diversion fitting 313 is the core component for realizing the switching of adsorption modes. Its design integrates pressure sensing control and sealing isolation technology, and can automatically adjust the fluid flow direction according to the operating status of the adsorption cylinder 311. The diversion pipe 3131 is made of corrosion-resistant material (such as PVDF, 316L stainless steel). The inner diameter of the pipe is designed according to the treatment flow rate (usually 20-50mm). One end of the pipe is sealed to the outlet end of the adsorption cylinder 311, and the other end is connected to the outlet pipe 3121 of the auxiliary cylinder 312 through a quick connector. It can achieve selective communication with 1-2 auxiliary cylinders 312, providing structural support for single-cylinder / multi-cylinder adsorption modes.

[0051] The outlet end of the adsorption cylinder 311 has several horizontally arranged filter ports. The annular sealing plate 3132 and the pressure blocking structure 3133 are located inside the outlet end and are fixed together by a connecting rod. When the pressure of the liquid discharged from the adsorption cylinder 311 exceeds the preset threshold, the blocking end of the pressure blocking structure 3133 opens and moves the annular sealing plate 3132 down through the connecting rod to seal and block the filter outlet, so that the liquid discharged from the adsorption cylinder 311 enters the auxiliary cylinder 312 through the diversion pipe 3131 for secondary adsorption.

[0052] The horizontal annular filter ports (8-12 in number, evenly distributed on the sidewall of the outlet end) at the outlet end of the adsorption cylinder 311 allow the liquid treated by the adsorption cylinder 311 to be directly discharged into the treatment buffer zone 321 through the filter ports in single-cylinder adsorption mode. The filter membrane (0.45μm pore size) built into the filter ports can trap tiny resin particles. The annular sealing plate 3132 (made of polytetrafluoroethylene, 5-8mm thick) and the pressure blocking structure 3133 are rigidly connected by a connecting rod to form a linkage control mechanism. The core components of the pressure blocking structure 3133 are a pressure sensor and an elastic blocking head, and the preset pressure threshold is usually 0.3-0.5MPa. Its working principle is as follows: When the defluorination resin in the adsorption cylinder 311 approaches saturation, the permeability of the resin layer decreases, leading to an increase in liquid pressure at the outlet. When the pressure exceeds a preset threshold, the pressure sensor triggers the elastic plug head to open, and simultaneously, the connecting rod drives the annular sealing plate 3132 to move downwards along the inner wall of the outlet, completely sealing and blocking the filter port. This prevents the liquid exiting the adsorption cylinder 311 from being discharged through the filter port and instead guides it through the diversion pipe 3131 into the auxiliary cylinder 312 for secondary adsorption. This design achieves automatic switching of adsorption modes without manual intervention, improving the automation level and operational stability of the equipment and preventing the effluent water quality from exceeding standards due to resin adsorption saturation.

[0053] See attached document Figure 3 (a, b) Figures 6 to 8The backwash assembly 314 includes a backwash pipe 3141 and a discharge pipe rack 3142. The water injection end of the backwash pipe 3141 is connected to the bottom end of one or two discharge pipes 3121, used to inject backwash medium into the discharge pipes 3121 to restore the defluorinating resin inside the auxiliary cylinder 312. One or two sludge collection hoods are fixedly connected to the discharge pipe rack 3142, located directly below the spare auxiliary cylinder 312, used to receive backwash wastewater inside the spare auxiliary cylinder 312. The discharge pipes 3121 are rotatably installed inside the auxiliary cylinder 312. Several sets of discharge ports 3122 are arranged equidistantly along the axis of the discharge pipes 3121, with the uppermost discharge port 3122 being an adsorption port and the others being flushing ports. A fixed shaft is fixedly attached to the inner top of the auxiliary cylinder 312, and a fixed connection is fixedly attached to the outer surface of the fixed shaft. Several baffles 3123 are used to seal and block the flushing inlets; a gear 3143 is fixed on the outer surface of the bottom end of the outlet pipe 3121, and an arc-shaped gear 3144 is fixedly connected to the inner surface of the treatment tower. The arc-shaped gear 3144 meshes with the gear 3143 to drive the circular motion of the outlet pipe 3121 to rotate; the flushing inlets on the outlet pipe 3121 in the adsorption cylinder 311 in the backwashing zone are open, allowing the backwashing medium to be sprayed out through all the outlets 3122, forming the restoration of the defluorination resin in different layers; the flushing inlets on the outlet pipe 3121 in the adsorption cylinder 311 in the area to be used are closed, so that when the liquid after one round of treatment passes through the outlet pipe 3121, it can only be discharged through the uppermost outlet 3122, forming a complete flow path from top to bottom, realizing a complete secondary defluorination operation.

[0054] The backwash assembly 314 is a key system for ensuring the regeneration efficiency of the defluorination resin and the continuous operation of the equipment. Its core design is to achieve online backwashing regeneration of the resin, while automatically switching between adsorption and flushing modes through structural linkage. The water injection end of the backwash pipe 3141 (made of PVDF, resistant to acid and alkali corrosion) is connected to the bottom end of the outlet pipe 3121 via a three-way valve, allowing selective injection of backwash medium (selected according to the resin type, such as 5-10% hydrochloric acid solution or 3-5% sodium hydroxide solution) into the outlet pipes 3121 of 1-2 spare auxiliary cylinders 312. The backwash medium permeates back into the defluorination resin layer through the outlet port 3122 on the outlet pipe 3121. Its working principle is to remove the fluoride ions adsorbed by the resin from the resin functional groups through chemical desorption, while simultaneously flushing away impurities trapped in the resin layer, thereby restoring the resin's adsorption performance.

[0055] The sludge collection hood (made of polypropylene and funnel-shaped) on the discharge pipe rack 3142 is located directly below the spare auxiliary cylinder 312. It is used to collect the sewage (containing fluoride ions, impurities and a small amount of resin debris) generated during the backwashing process. The sewage is discharged through the discharge pipe rack 3142 to the sewage treatment system for further treatment to avoid environmental pollution.

[0056] The outlet pipe 3121 is installed in a rotating manner (with bearing seal to ensure rotational flexibility and sealing). Its outlet 3122 is divided into adsorption outlet and flushing outlet, which are equidistantly arranged along the axis (5-10cm spacing). The uppermost adsorption outlet is used for fluid discharge during secondary adsorption, and the remaining flushing outlets are used for spraying backwashing media.

[0057] The fixed shaft at the top of the auxiliary cylinder 312 and the baffle frame 3123 form a sealing mechanism. The number of baffle frames 3123 is the same as the number of flushing inlets. Their function is to seal and block the flushing inlets through the baffle frames 3123 when the auxiliary cylinder 312 is in the working state (secondary adsorption) to prevent liquid from leaking from the flushing inlets and ensure the fluid discharge efficiency of the adsorption inlets. When the auxiliary cylinder 312 is switched to the standby state (backwashing), the discharge pipe 3121 rotates (rotation angle 30-60°) through the meshing action of the gear 3143 and the arc-shaped gear frame 3144, causing the baffle frame 3123 to be misaligned with the flushing inlets, the flushing inlets open, and the backwashing medium can be evenly sprayed into the resin layer through the flushing inlets.

[0058] The meshing transmission design of gear 3143 and arc-shaped gear frame 3144 realizes the linkage control of the ring motion of auxiliary cylinder 312 and the rotation of outlet pipe 3121. When the rotary motor group 315 drives the auxiliary cylinder 312 to switch positions, the outlet pipe 3121 rotates synchronously, automatically completing the switching of adsorption / rinsing inlet. No additional power source is required, which simplifies the equipment structure and improves the reliability of operation.

[0059] Refer to the attached diagram. Figure 3 (a, b) and Figure 5 (a, b, c) The alkali recycling unit 320 includes a processing buffer zone 321 and a high-quality zone 322; The processing buffer zone 321 is cone-shaped, with a sedimentation area at its bottom. A slag discharge pipe is installed at the bottom to remove residual resin debris and suspended solids from the alkali solution using gravity settling. An automatic slag discharge valve is installed on the slag discharge pipe. A flow diversion unit is installed on the processing buffer zone 321, comprising a conical ring plate 3211 and a waterproof drive component 3212 for rotating the conical ring plate 3211. A flow diversion port A is provided on the processing buffer zone 321. The conical ring plate 3211 is tightly fitted to the top of the processing buffer zone 321. A connecting port B is provided on the side, which partially overlaps with the drainage port A to form a merging port C. The liquid that has settled inside the processing buffer 321 is drained to the refinement area 322 through the merging port C. The bottom of the refinement area 322 is fixedly connected to an alkali recovery pipe 3221. An online alkali concentration detector 3222 and a mixing pipe are installed on the alkali recovery pipe 3221. The online alkali concentration detector 3222 is used to detect the alkali concentration. An appropriate amount of clean water or concentrated alkali is added through the mixing pipe to adjust the alkali concentration to the standard range suitable for the photovoltaic etching process.

[0060] The alkali recycling unit 320 adopts a process design of "buffer sedimentation-layered diversion-concentration control". Its core objective is to achieve the purification and recycling of alkali and reduce the consumption of alkali reagents in photovoltaic production.

[0061] The processing buffer zone 321 adopts a conical structure (cone angle 90°). Its design principle is to use the gravity sedimentation effect to accelerate the sedimentation of residual resin debris (particle size ≥1μm) and suspended matter in the alkaline solution. The sedimentation area at the bottom is used to collect sedimented impurities. The slag discharge pipe (made of 316L stainless steel) is installed at the lowest point of the sedimentation area. With the help of the automatic slag discharge valve (using an electric ball valve with a control accuracy of ±1%), the slag can be automatically discharged at timed intervals according to the amount of sediment, so as to avoid the accumulation of impurities and affect the treatment effect.

[0062] The drainage unit is the core component for realizing the stratified export of alkali solution. The drainage port A on the processing buffer 321 is the fluid export channel. The conical ring plate 3211 is tightly fitted to the top of the processing buffer 321 (sealed with a PTFE gasket to prevent leakage). The connecting port B on its side partially overlaps with the drainage port A to form the overlapping port C. The conical ring plate 3211 is driven to rotate by a waterproof drive component 3212 (using a waterproof stepper motor, protection level IP65, speed 5-10r / min), which can adjust the position and size of the overlapping port C.

[0063] Its working principle is as follows: after sedimentation, the liquid in the processing buffer 321 forms layers, with the upper layer being a clear alkaline solution (containing a small amount of impurities) and the lower layer being a turbid liquid containing impurities; by rotating the conical ring plate 3211, the overlapping port C is always located in the upper clear alkaline solution area, realizing the separate diversion of the clear alkaline solution, preventing the lower turbid liquid from entering the refined area 322, and ensuring the alkaline solution refining effect.

[0064] The refined alkali solution unit 322, serving as the alkali concentration control unit, has the core function of adjusting the concentration of the refined alkali solution to the suitable range for the photovoltaic etching process (typically 5-10% NaOH). An online alkali concentration detector 3222 (using an ultrasonic concentration sensor, measurement range 0-20%, accuracy ±0.1%) is installed on the alkali recovery pipe 3221 at the bottom, which can detect the alkali concentration in real time and transmit the data to the intelligent control unit. The mixing pipe is divided into a clean water mixing pipe and a concentrated alkali mixing pipe. Based on the concentration detection results, the intelligent control unit automatically controls the valve opening of the mixing pipe, adding an appropriate amount of clean water (to dilute excessively concentrated alkali solution) or concentrated alkali (to increase excessively low concentration alkali solution), achieving precise control of the alkali concentration. The regulated alkali solution is then transported through the alkali recovery pipe 3221 to the storage tank of the photovoltaic etching process for reuse, realizing the recycling of alkali resources, reducing production costs, and simultaneously reducing wastewater discharge.

[0065] See attached document Figure 5 (a, b, c) Drainage port A is vortex-shaped, less than one turn, used to gradually move downwards in a vortex shape from the high side position of the processing buffer 321 when the conical ring plate 3211 rotates. This changes the height of the overlapping port B (moving from high to low), thereby enabling the separate extraction of the upper layer liquid (high-quality alkali solution) after the alkali solution is separated. Drainage port A is equipped with a filter membrane to isolate resin debris and suspended matter. The overlapping port B is a cone shape that is wider at the top and narrower at the bottom. When the conical ring plate 3211 rotates, the diameter of the overlapping port C (moving from high to low) decreases as it moves downwards. This prevents the overlapping port C from interfering with the resin debris and suspended matter located below when it moves close to the space between the upper and lower layers due to an excessively large opening, thus affecting the extraction of the high-quality alkali solution.

[0066] The structural design of the inlet A and the connecting port B revolves around "precise stratified inlet drainage and ensuring the purity of the alkali solution," and is a key structure for alkali solution refining. The inlet A is designed in the shape of a vortex (arc length less than 360°, usually 270°), and its core function is to cooperate with the rotation of the conical ring plate 3211 to achieve continuous and adjustable height of the overlapping port C.

[0067] When the conical ring plate 3211 rotates, the overlapping position of the connecting port B and the vortex drain port A gradually moves from high to low along the vortex trajectory, so that the overlapping port C is always aligned with the upper clear alkaline solution area in the processing buffer 321, avoiding the extraction of the lower layer of turbid liquid containing impurities.

[0068] The filter membrane (made of polyethersulfone, pore size 0.22μm) installed in the inlet A works by using physical retention to further remove residual tiny resin debris (particle size ≥0.22μm) and suspended solids from the upper clarified alkaline solution, ensuring the purity of the alkaline solution entering the refinement zone 322 (suspended solids content ≤10mg / L). The connecting port B is designed as a cone shape (wider at the top and narrower at the bottom, cone angle 30-45°). Its structural advantage is that as the overlapping port C rotates from high to low with the conical ring plate 3211, the actual flow diameter of the overlapping port C gradually decreases. The core function of this design is to prevent the overlapping port C from having an excessively large opening near the upper and lower liquid separation interface, causing the liquid flow rate to be too fast and flushing away the resin debris and suspended solids settled in the lower layer, thus preventing them from being resuspended and entering the refinement zone 322. By using a gradually decreasing diameter design, the upper clarified alkaline solution can be successfully extracted while minimizing interference with the layering interface, ensuring the purity of the extracted alkaline solution and providing high-quality raw materials for subsequent concentration control and reuse.

[0069] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for recycling and treating fluoride-containing wastewater from the photovoltaic industry, characterized in that, include: The pretreatment module (100), acid-base coupling reaction module (200), and deep purification and recovery module (300) are connected in sequence. The pretreatment module (100) includes a concentrated acid wastewater pretreatment unit (110) and a concentrated alkali wastewater pretreatment unit (120) arranged in parallel, which are used to pretreat concentrated acid fluoride wastewater and concentrated alkali silicon wastewater generated by the photovoltaic industry, respectively. The acid-base coupling reaction module (200) is an induced crystallization fluidized bed reactor, used to receive the pretreated wastewater output from the fractional pretreatment module (100) to realize the granular recovery of fluoride ions and the synergistic treatment of acid and base. The deep purification and recovery module (300) includes a treatment tower and a resin adsorption unit (310) and an alkali recycling unit (320) disposed inside the treatment tower. The resin adsorption unit (310) and the alkali recycling unit (320) are connected sequentially from top to bottom. The resin adsorption unit (310) is used to adsorb and remove residual fluoride ions from the liquid output by the acid-base coupling reaction module (200). The alkali recycling unit (320) is used to classify, store and recycle the liquid after removing residual fluoride ions.

2. The photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment according to claim 1, characterized in that: The concentrated acid wastewater pretreatment unit (110) includes a first filtration chamber and an acid buffer chamber connected in sequence; The first filtration chamber is equipped with a detachable ceramic filter plate for removing solid impurities from wastewater. The bottom of the acid buffer chamber is equipped with a pH sensor and a temperature sensor for real-time monitoring of water quality parameters. The acid buffer chamber is electrically connected to the intelligent control unit, which regulates the pH value of the acid entering the subsequent units.

3. The photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment according to claim 1, characterized in that: The concentrated alkaline wastewater pretreatment unit (120) includes a second filtration chamber, a silicon removal reaction chamber, and a calcium removal adsorption chamber connected in sequence. The second filtration chamber is equipped with a stainless steel filter screen for removing large particulate impurities; The silicon removal reaction chamber is equipped with a stirring assembly and a calcium hydroxide dosing port, and the inner wall of the chamber is equipped with a heating jacket for regulating the reaction temperature. The calcium removal adsorption chamber is filled with a highly selective chelating resin layer for selectively adsorbing calcium ions, and filter support structures are provided at both ends of the resin layer. The calcium removal adsorption chamber is provided with a regenerant injection port.

4. The photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment according to claim 3, characterized in that: The reactor body of the acid-base coupling reaction module (200) is provided with a clear water zone, a separation zone, a granulation zone, a sedimentation zone and a neutralization reaction sedimentation zone from top to bottom; The granulation zone is provided with a seed inlet and an internal reflux channel on its sidewall. The internal reflux channel is connected to the neutralization reaction precipitation zone at the bottom of the reactor body. The neutralization reaction precipitation zone is connected to the acid buffer chamber of the concentrated acid wastewater pretreatment unit (110) and the outlet of the calcium removal adsorption chamber of the concentrated alkali wastewater pretreatment unit (120) through pipelines, and the pipelines are equipped with flow control valves. The bottom of the settling zone is provided with a conical discharge port for discharging calcium fluoride particles, and the separation zone is provided with an overflow port for discharging clean water.

5. The photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment according to claim 1, characterized in that: The resin adsorption unit (310) includes an adsorption cylinder (311), several auxiliary cylinders (312), a diversion pipe (313), a backwashing assembly (314), and a rotary motor assembly (315). The adsorption cylinder (311) and several auxiliary cylinders (312) are all located inside the treatment tower and are all filled with defluorination resin. The adsorption cylinder (311) is located between several auxiliary cylinders (312). The diversion fitting (313) is used to selectively connect the adsorption cylinder (311) to one or two auxiliary cylinders (312) to form single-cylinder adsorption or multi-cylinder adsorption. The rotary motor assembly (315) is connected to several auxiliary cylinders (312) for driving several auxiliary cylinders (312) to move in a ring around the adsorption cylinder (311) as the axis, thereby realizing the switching of the position of the standby auxiliary cylinder (312); The backwashing assembly (314) is used to restore the defluorination resin inside the spare auxiliary cylinder (312).

6. The photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment according to claim 5, characterized in that: The bottom of the auxiliary cylinder (312) is provided with a water filtration area. An outlet pipe (3121) is installed inside the auxiliary cylinder (312). An outlet port (3122) is opened on the outer surface of the outlet pipe (3121). A filter membrane is provided inside the outlet port (3122). The outlet end of the diversion pipe (313) is connected to the bottom end of the outlet pipe (3121) to selectively discharge the liquid treated inside the adsorption cylinder (311) into the outlet pipe (3121), and then discharge it through the outlet port (3122) on the outlet pipe (3121) to achieve secondary fluoride ion adsorption.

7. The photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment according to claim 5, characterized in that: The diversion fitting (313) includes a diversion pipe (3131), an annular sealing plate (3132), and a pressure blocking structure (3133). The diversion pipe (3131) is located inside the treatment tower and can be connected to one or two outlet pipes (3121). The diversion pipe (3131) is connected to the outlet end of the adsorption cylinder (311). The adsorption cylinder (311) has several horizontally arranged filter ports at its outlet end. The annular sealing plate (3132) and the pressure blocking structure (3133) are located inside the outlet end and are fixed together by a connecting rod. When the liquid pressure discharged from the adsorption cylinder (311) exceeds the preset threshold, the blocking end of the pressure blocking structure (3133) opens, and the annular sealing plate (3132) moves down through the connecting rod to seal and block the filter outlet, so that the liquid discharged from the adsorption cylinder (311) enters the auxiliary cylinder (312) through the diversion pipe (3131) for secondary adsorption.

8. The photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment according to claim 5, characterized in that: The backwash assembly (314) includes a backwash pipe (3141) and a discharge pipe rack (3142). The water injection end of the backwash pipe (3141) is connected to the bottom end of one or two outlet pipes (3121) to inject the backwash medium into the outlet pipe (3121) to restore the defluorination resin inside the auxiliary cylinder (312). One or two sludge collection hoods are fixedly connected to the discharge pipe rack (3142). The sludge collection hoods are located directly below the spare auxiliary cylinder (312) and are used to receive backwash wastewater inside the spare auxiliary cylinder (312). The outlet tube (3121) is installed inside the auxiliary cylinder (312) by rotation. The outlet ports (3122) on the outlet tube (3121) are in several groups, which are equidistantly arranged along the axis of the outlet tube (3121). The uppermost outlet port (3122) is an adsorption port, and the rest are rinsing ports. The inner top of the auxiliary cylinder (312) is fixed with a fixed shaft, and a number of baffles (3123) for sealing and blocking the flushing inlet are fixedly connected to the outer surface of the fixed shaft. A gear (3143) is fixed on the outer surface of the bottom end of the outlet pipe (3121), and an arc-shaped gear frame (3144) is fixedly connected to the inner surface of the processing tower. The arc-shaped gear frame (3144) meshes with the gear (3143) to drive the outlet pipe (3121) in ring motion to rotate.

9. The photovoltaic industry fluoride-containing wastewater resource recovery and treatment equipment according to claim 1, characterized in that: The alkali recycling unit (320) includes a processing buffer zone (321) and a high-quality zone (322); The processing buffer (321) is cone-shaped, with a sedimentation area at the bottom and a slag discharge pipe installed at the bottom to remove residual resin debris and suspended matter in the alkali solution by gravity sedimentation. An automatic slag discharge valve is installed on the slag discharge pipe. The processing buffer (321) is equipped with a drainage unit, which includes a conical ring plate (3211) and a waterproof drive component (3212) for rotating the conical ring plate (3211). The processing buffer (321) has a drainage port A. The conical ring plate (3211) is tightly attached to the top of the processing buffer (321), and a connecting port B is opened on the side of the conical ring plate (3211). The connecting port B and the drainage port A partially overlap to form a coinciding port C. The liquid that has settled inside the processing buffer (321) is drained to the premium area (322) through the coinciding port C. The bottom of the premium area (322) is fixedly connected to an alkali recovery pipe (3221). The alkali recovery pipe (3221) is equipped with an online alkali concentration detector (3222) and a mixing pipe. The online alkali concentration detector (3222) is used to detect the alkali concentration. By adding an appropriate amount of clean water or concentrated alkali through the mixing pipe, the alkali concentration is adjusted to the standard range suitable for the photovoltaic etching process.

10. A photovoltaic industry fluoride-containing wastewater resource recovery and treatment device according to claim 9, characterized in that: The drain port A is vortex-shaped, and a filter membrane for isolating resin debris and suspended matter is provided inside the drain port A; the overlapping port B is a cone-shaped structure that is wider at the top and narrower at the bottom.

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