Hydrofluoric acid wastewater recovery system that can extract industrial raw materials

Abstract

To provide a recovery system for extracting industrial raw materials from wastewater containing hydrofluoric acid.SOLUTION: There is provided a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials, including: a wastewater collection tank 90, an activated carbon filter 91, a capacitive deionizer 92, a low-concentration collection tank 60, at least one filter 80, a high-concentration collection tank 30, a reactor 10, and a dehydrator 50. The wastewater collection tank contains hydrofluoric acid wastewater. The activated carbon filter is connected to the wastewater collection tank. The capacitive deionizer is connected to the activated carbon filter. The low concentration collection tank is connected to the capacitive deionizer and receives low concentration fluoride wastewater. The filter is connected to the low-concentration collection tank and filters the low-concentration fluoride wastewater to form recovered water. The high-concentration collection tank is connected to the capacitive deionizer and receives the high-concentration fluorine wastewater. The reactor is connected to the high-concentration collection tank. The dehydrator is connected to the reactor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wastewater recovery system, and more particularly to a recovery system for extracting industrial raw materials from wastewater containing hydrofluoric acid. [Background technology]

[0002] Taiwan has a developed high-tech industry and is a major R&D and manufacturing base for semiconductors, displays, and other high-tech industries around the world. In the manufacturing processes of integrated circuit semiconductors, liquid crystal display panels, and solar energy, large amounts of solutions containing hydrofluoric acid are used for etching and surface cleaning. After etching or cleaning, hydrofluoric acid wastewater is generated. The fluoride ion concentration in this wastewater ranges from approximately 1,000 to 3,500 mg / L, sometimes exceeding 10,000 mg / L. However, this hydrofluoric acid wastewater containing high-purity fluoride ions cannot be directly excreted because fluoride is ingested through water or food and accumulates in the body. Ingestion of large amounts of fluoride can disrupt the calcium-phosphorus metabolic balance, leading to tooth brittleness, skin rashes, and skeletal and joint deformations, resulting in skeletal fluorosis. This hydrofluoric acid wastewater containing high-purity fluoride ions sometimes enters wastewater treatment systems. In conventional technology, calcium fluoride sludge is produced by chemical coagulation to reduce the fluoride ion concentration in hydrofluoric acid wastewater and meet wastewater standards, but the large amount of sludge generated must be buried or otherwise treated, which is costly. Therefore, there has been a demand for technology that can reuse this hydrofluoric acid wastewater as a resource.

[0003] The "method for producing calcium fluoride from wastewater containing hydrofluoric acid, hexafluorosilicic acid, and hexafluoroaluminic acid" in Patent Document 1 involves adding potassium fluoride to wastewater containing hydrofluoric acid, hexafluorosilicic acid, and hexafluoroaluminic acid, and then allowing the mixture to settle with the aid of chemicals such as ammonia, calcium hydroxide, and a flocculant, followed by filtration to obtain calcium fluoride. However, the steps in the treatment method in Patent Document 1 are complicated, and in order to produce calcium fluoride through the precipitation and filtration process, it was necessary to constantly mix the chemicals and wastewater in different weight ratios to produce a mixed solution and adjust the pH value.

[0004] The "fluorine-containing wastewater treatment method and treatment agent therefor" of Patent Document 2 involves adding a mixed chemical agent consisting of aluminum-containing or sodium-containing compounds or combinations thereof to the fluorine-containing wastewater after it has been allowed to stand, adjusting the pH of the fluorine-containing wastewater, removing cations from the fluorine-containing wastewater, and then adding a treatment agent consisting of aluminum-containing, sodium-containing, or chlorine-containing compounds to chemically coagulate the fluoride ions and the chemical agent in the fluorine-containing wastewater, forming cryolite precipitates, and achieving other uses. However, the treatment method of Patent Document 2 involves complex steps, such as separately adding a mixed chemical agent to adjust the pH to a suitable value and help remove cation interferences. This step also requires the formation of various metal hydroxides in the fluorine-containing wastewater, which are then removed to prevent subsequent interferences. Furthermore, the addition of an aluminum compound to form the cryolite precipitate and the additional chemical agent increases costs and also increases waste generation due to the need to remove the various metal hydroxides that form.

[0005] The "method for recovering fluorine from hydrofluoric acid waste liquid and producing fluorosilicate" described in Patent Document 3 involves reacting a hydrofluoric acid-containing waste liquid with a silicon-containing compound to produce a hexafluorosilicic acid-containing waste liquid (HSiF), adjusting the concentration of the hexafluorosilicic acid-containing waste liquid and adding an alkali or alkali metal salt containing sodium or potassium to produce a fluorosilicate precipitate. The sodium fluorosilicate or potassium fluorosilicate is then separated from the waste liquid and dried, resulting in recoverable sodium fluorosilicate and potassium fluorosilicate products. However, the treatment method described in Patent Document 3 is subject to operational restrictions requiring the hydrofluoric acid-containing waste liquid and the hydrosilicic acid-containing waste liquid to be maintained at 5 to 15 wt %. If the concentration is too low or too high, economical fluorosilicate cannot be produced, resulting in increased operating costs.

[0006] With the growing awareness of environmental protection, the concepts of energy conservation and carbon dioxide emission reduction are becoming increasingly important. However, with the technologies disclosed to date, it is not possible to recover and reuse fluorine-containing wastewater without adding various solvents and chemical aids to adjust the pH value, etc., which increases the overall treatment cost. In addition, the addition of separate solvents and chemicals is inconsistent with the concepts of environmental protection, energy conservation, and carbon dioxide emission reduction, and also generates related waste liquids or waste materials.

[0007] In view of the current situation, the present inventor has made various efforts based on his many years of experience and knowledge in manufacturing and design in the related fields, and has completed the present invention. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Taiwan Patent No. I574923 [Patent Document 2] Taiwan Patent No. I233428 Publication [Patent Document 3] Taiwan Patent No. I353343 Summary of the Invention [Problem to be solved by the invention]

[0009] The main object of the present invention is to provide a hydrofluoric acid wastewater recovery system in which the liquid flow pattern and flow rate during the contact reaction between the sodium aluminum compound and the high-concentration fluoride wastewater are controlled by a distributor and a control panel in the system reaction tank, and the pH value and fluoride ion concentration of the mixed water sample of the high-concentration fluoride wastewater and the sodium aluminum compound are monitored by a pH value / fluoride ion detection section in a loop configuration and connected to the system reaction tank, thereby effectively controlling factors affecting the purity of cryolite crystals during the operation of the system, allowing the system to stably form crystals of high purity, recover and reuse cryolite, increase the recovery rate of fluoride ions, and obtain economical cryolite crystals, which can be used to extract industrial raw materials. [Means for solving the problem]

[0010] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized as the following application examples (1) to (11). Application example (1) A hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials, comprising a wastewater collection tank, an activated carbon filtration device, a capacitive deionization device, a low-concentration collection tank, at least one filtration device, a high-concentration collection tank, a reactor, and a dehydration device, the wastewater collection tank contains hydrofluoric acid wastewater; the activated carbon filtration device is connected to the wastewater collection tank and filters the hydrofluoric acid wastewater to generate a first wastewater; the capacitive deionizer is connected to the activated carbon filter and has a plurality of oppositely charged electrodes; causing ions in the first wastewater to migrate toward a plurality of corresponding electrodes of opposite charge to form a low-fluoride wastewater; By desorbing and releasing ions from multiple electrodes, high-concentration fluoride wastewater is formed. the low-concentration collection tank is connected to the capacitive deionization device and stores low-concentration fluoride wastewater; the filtration device is connected to the low-concentration collection tank and filters the low-concentration fluoride wastewater to form recovered water, which is returned to the factory for internal reuse; the high-concentration collection tank is connected to the capacitive deionization device and stores the high-concentration fluoride wastewater; the reactor is connected to the high-concentration collection tank, and generates cryolite and a third wastewater by reacting the added aluminum sodium-containing compound with the high-concentration fluoride wastewater; The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials is characterized in that the dehydration device is connected to the reaction device and separates the cryolite and the third wastewater. Application example (2) The capacitive deionization device is a CDI (Capacitive De-Ionization) or a thin film capacitive deionization device; The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to the above-mentioned Application Example (1), wherein the aluminum sodium-containing compound is sodium aluminate. Application example (3) the ions in the first wastewater include fluoride ions and hydrogen ions; the fluoride ion concentration in the high-fluoride concentration wastewater is higher than the fluoride ion concentration in the low-fluoride concentration wastewater, The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to the above-mentioned Application Example (1), wherein the fluoride ion concentration in the high-concentration fluoride wastewater is higher than the fluoride ion concentration in the hydrofluoric acid wastewater. Application example (4) The filtration device is connected to the wastewater collection tank, the low-concentration collection tank, or both the low-concentration collection tank and the wastewater collection tank; The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to the above-mentioned application example (1), wherein the filtration device is a reverse osmosis (RO) device or a thin-film capacitive deionization device. Application example (5) further comprising a control processor; The reactor has a top vessel inlet and a bottom outlet corresponding to each other, The reactor is provided with a distributor having a plurality of liquid holes therein, and a control panel located on the distributor and having a plurality of through-holes therein, The distributor and the control panel are installed at an interval inside the reactor, forming an upper dosing space and a lower reaction space; the upper dosage space has a sodium aluminate level indicator; The lower reaction space communicates with the discharge control section through the bottom outlet, and discharges a mixed water sample formed by the aluminum sodium-containing compound and the high-concentration fluoride wastewater; reacting the mixed water sample to produce the cryolite and the third wastewater; the sodium aluminate level meter and the discharge control section are electrically controlled by the control processor; the discharge control section is connected to the dehydration device and the waste liquid tank to separate the cryolite and the third waste water; the dehydration device and the waste liquid tank are electrically controlled by the control processor; the dehydration device is in communication with the discharge control section of the reactor; The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to the above-mentioned application example (1), wherein the waste liquid tank collects the third wastewater discharged by the dehydration device. Application example (6) the lower reaction space of the reactor has a hydrofluoric acid level gauge electrically controlled by the control processor; the discharge control section of the reactor includes a flow control valve and a ball valve; a discharge passage between the flow control valve and the bottom outlet of the reactor; the discharge flow path is controlled by the ball valve; the flow control valve and the ball valve of the discharge control section and the ball valve of the discharge flow path are electrically controlled by the control processor; Further provided with a sodium aluminate chemical tank and a pH value / fluoride ion detection section, The sodium aluminate chemical tank is electrically controlled by the control processor through a batch quantity control section, and the sodium aluminum compound is added into the upper dosage space of the reactor; the pH value / fluoride ion detection section has a pH meter and a fluorometer that are electrically controlled by the control processor and communicate with each other, supplies the mixed water sample to the pH meter and the fluorometer, and detects the pH value and fluoride content of the mixed water sample discharged by the discharge control section; the pH meter has a first flow path communicating with the bottom of the lower reaction space of the reactor; The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to Application Example (5) is characterized in that the fluorometer has a second flow path communicating with the top of the lower reaction space, and the mixed water sample is returned to the reaction device or discharged. Application example (7) The plurality of liquid holes of the distributor are formed in a U-shaped radial pattern from the center of a circle, the plurality of through holes of the control panel are composed of a first through hole group, a second through hole group, and a third through hole group, the first through hole group, the second through hole group, and the third through hole group are formed in a U-shaped radial pattern from the center of the control panel, and an angle is formed between adjacent radial directions, the first through-hole group has the same number of through-holes as the number of liquid holes of the distributor, The second through-hole group and the third through-hole group have a different number of through-holes than the number of the liquid holes of the distributor, The distributor has a plurality of positioning holes, The control panel has three sets of position restraint holes corresponding to the positions and number of the positioning holes of the distribution panel, and an angle is formed between the position restraint holes of each set, The pair of position restraint holes of the control panel and the positioning holes of the distribution panel can be aligned, The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to the above-mentioned application example (5), wherein the distributor and the control panel are fixed by inserting a plurality of positioning pins, the number of which corresponds to the number of the positioning holes. Application example (8) the high-concentration collection tank has a level gauge and a discharge valve; the batch quantity control section of the high concentration collection tank has a transfer pump; two ball valves are provided between the transfer pump and the high-concentration collection tank and ... the batch quantitative control section of the high-concentration collection tank is provided with a hydrofluoric acid flow meter adjacent to the reactor; In the high-concentration collection tank, the level meter, the transfer pump, the two ball valves, the hydrofluoric acid flow meter, and the discharge valve are electrically controlled by the control processor; The sodium aluminate chemical tank has a level gauge and a discharge valve, the batch quantity control section of the sodium aluminate chemical tank has a transfer pump; Two ball valves are provided between the transfer pump and the sodium aluminate chemical tank and between the transfer pump and the reactor, respectively; The batch quantitative control section of the sodium aluminate chemical tank is provided with a sodium aluminate flow meter adjacent to the reactor, In the sodium aluminate chemical tank, the level meter, the transfer pump, the two ball valves, the sodium aluminate flow meter, and the discharge valve are electrically controlled by the control processor; the first flow path of the pH value / fluoride ion detection section has a measurement pump; a flow control valve and a ball valve are provided between the reaction device and the measuring pump; a ball valve and a clean water input section are provided between the measuring pump and the pH meter; the clean water input section has a flow control valve for controlling the amount of clean water input; the second flow path has a reflux control valve; the fluorometer has a third flow path; the third flow path has a discharge control valve and a ball valve to control the discharge of waste liquid; In the pH value / fluoride ion detection section, the measuring pump, the two flow control valves, the three ball valves, and the discharge control valve are electrically controlled by the control processor; an end opening of the second flow path communicating with the interior of the reaction device is provided from an upper tank wall of a lower reaction space of the reaction device to a center of the upper tank of the lower reaction space; the waste liquid tank has a level gauge, a discharge valve, and a low-concentration fluorine wastewater output section; a ball valve for controlling the flow rate of the third wastewater is provided between the waste liquid tank and the dehydration device; the low-concentration fluorine wastewater output section has a transfer pump and two ball valves, one of which is provided between the transfer pump and the waste liquid tank and the other of which is provided at the discharge end of the transfer pump connected to the wastewater output section; The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to (6) above, wherein in the waste liquid tank, the level meter, the discharge valve, the transport pump, and the three ball valves are electrically controlled by the control processor. Application example (9) The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to the above-mentioned application example (6) is installed on an overflow prevention base, An overflow prevention body is provided around the periphery of the overflow prevention base, and the overflow prevention body has a leak detection device electrically controlled by the control processor and a drain valve provided at the bottom of the overflow prevention base, Further comprising a seed crystal reservoir; the seed crystal storage tank stores seed crystals therein and is installed in the fourth flow path; the fourth flow path communicates with the reactor and the discharge control section thereof; a transfer pump is installed between the seed crystal storage tank and the discharge control section; The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to the above-mentioned application example (6) is characterized in that the fourth flow path guides the mixed water sample discharged from the discharge control section to the seed crystal storage tank and then returns it to the reactor, and introduces the seed crystals into the reactor. Application example (10) the control processor executes a control method including a parameter setting step, a high-concentration fluoride wastewater injection step, an aluminum sodium-containing compound addition step, a step of allowing the mixed water sample to stand, a step of supplying the mixed water sample to the pH value / fluoride ion detection section, a reaction end point determination step, and a solid-liquid separation step; In the parameter setting step, the control processor sets parameter items and numerical ranges of the parameter items, and installs the distributor and the control panel based on the flow rate needs of the aluminum-sodium-containing compound to control the flow rate of the aluminum-sodium-containing compound falling into the lower reaction space; In the high-concentration fluorine wastewater injection step, the batch quantitative control section of the high-concentration collection tank is activated, and the high-concentration fluorine wastewater is injected into the lower reaction space of the reactor according to the set values ​​in the parameter setting step; In the aluminum sodium-containing compound adding step, after the high-concentration fluoride wastewater is completely injected into the reactor, the batch quantity control section of the sodium aluminate chemical tank is started, and the aluminum sodium-containing compound is added into the upper dosing space of the reactor according to the set value in the parameter setting step, to form the mixed water sample; In the step of allowing the mixed water sample to stand, calculation of a reaction standing time is started based on the set values ​​in the parameter setting step; In the step of supplying the mixed water sample to the pH value / fluoride ion detection section, when the reaction static time measurement is completed, the pH value / fluoride ion detection section is started, the mixed water sample in the reaction device is supplied to the pH value / fluoride ion detection section, the pH value and the fluoride ion concentration of the mixed water sample are read, and the mixed water sample is returned to the reaction device; In the reaction end point determination step, the control processor determines the reaction end point based on the read pH value and fluoride ion concentration of the mixed water sample, and when the reaction has not reached the reaction end point, performs a pH value / fluoride ion detection section closing step and an aluminum sodium-containing compound fine adjustment step, and adds a trace amount of aluminum sodium-containing compound to the reaction device based on the parameters set in the parameter setting step and the read pH value, and repeats the step of adding aluminum sodium-containing compound, the step of leaving the mixed water sample to stand, the step of supplying the mixed water sample to the pH value / fluoride ion detection section, and the reaction end point determination step until the reaction reaches the reaction end point, The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to Application Example (9), wherein in the solid-liquid separation step, when the reaction reaches the reaction end point, the discharge control section of the reactor is started, followed by a crystallization dehydration and collection step and a third wastewater discharge step, and after these steps are completed, a discharge control section closing step of the reactor is performed. Application example (11) The control method further includes an automatic mode determination step; said control processor pre-setting the current operation to either an automatic mode or a manual mode; If in automatic mode, automatically control the control processor, starting from the step of injecting high-concentration fluoride wastewater, and repeat the steps described above; The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to Application Example (10), wherein, when the system is in the manual mode, the control processor stops the automatic control, returns to the parameter setting step, and starts the automatic control after the parameter setting is completed. [Effects of the Invention]

[0011] The hydrofluoric acid wastewater recovery system of the present invention, which is capable of extracting industrial raw materials, uses a distributor and control panel in the system's reaction tank to control the liquid flow pattern and flow rate during the contact reaction between the sodium aluminum compound and the high-concentration fluoride wastewater, and a pH / fluoride ion detection section in a loop configuration and connected to the system's reaction tank monitors the pH and fluoride ion concentration of the mixed water sample of the high-concentration fluoride wastewater and the sodium aluminum compound. This effectively controls factors affecting the purity of cryolite crystals during system operation, allowing the system to stably form crystals of high purity, allowing the cryolite to be recovered and reused, increasing the fluoride ion recovery rate and producing cost-effective cryolite crystals. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a system flow diagram showing a portion of a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to an embodiment of the present invention. [Figure 2] 1 is a flow chart showing the process of a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention. [Figure 3] 1 is a block diagram showing a part of a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention. [Figure 4] 1 is a side view showing a structure of a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to an embodiment of the present invention, which is mounted on an overflow prevention base. FIG. [Figure 5] FIG. 2 is an explanatory diagram showing the distribution of liquid holes on the control panel of the hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention. [Figure 6] FIG. 2 is an explanatory diagram showing the distribution of through-holes in a distribution plate of a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention. [Figure 7] FIG. 10 is an explanatory diagram illustrating a state in which the liquid holes of the control panel and the second group of through holes of the distribution panel are combined in the hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention. [Figure 8] FIG. 1 is an explanatory diagram illustrating a state in which the liquid holes of the control panel and the first through-hole group of the distribution panel are combined in a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention. [Figure 9] FIG. 10 is an explanatory diagram illustrating a state in which the liquid holes of the control panel and the third through-hole group of the distribution panel are combined in the hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention. [Figure 10] 1 is a flow chart showing a crystal operation control method of the equipment of the present invention. [Figure 11] 1 is a configuration diagram showing a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] In order to more completely and clearly disclose the technical means of the present invention and the effects that can be achieved thereby, the present invention will be described in detail below in conjunction with the accompanying drawings and symbols disclosed.

[0014] Please refer to Fig. 11. As shown in Fig. 11, a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention includes a wastewater collection tank 90, an activated carbon filtration device 91, a capacitive deionization device 92, a low-concentration collection tank 60, at least one filtration device 80, a high-concentration collection tank 30, a reaction device 10, a dehydration device 50, a pH value / fluoride ion detection section 40, a sodium aluminate chemical tank 20, a waste liquid tank 81, and a control processor A (see Fig. 4) that electrically controls the above-mentioned device mechanisms.

[0015] Please refer to Figure 3. As shown in Figure 3, a hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to one embodiment of the present invention is installed entirely on an overflow prevention base 70. An overflow prevention body 71 that prevents the liquid from leaking and spreading is provided around the periphery of the overflow prevention base 70, and the system also has a leak detection device 72 electrically controlled by control processor A and a drain valve 73 provided at the bottom of the overflow prevention base 70. The leak detection device 72 detects whether or not there is a liquid leak, and when a liquid leak occurs, the drain valve 73 is electrically activated to discharge the liquid from the overflow prevention base 70.

[0016] 1 and 2, as shown in Fig. 1 and 2, a wastewater collection tank 90 receives and purifies hydrofluoric acid wastewater 901. In this embodiment, the wastewater collection tank 90 is connected to an activated carbon filtration device 91.

[0017] Referring to FIGS. 1 and 2, an activated carbon filter 91 is connected to a wastewater collection tank 90. ​​The activated carbon filter 91 filters hydrofluoric acid wastewater 901 from the wastewater collection tank 90. ​​The activated carbon filter 91 has a porous structure, which is a stack of hexacyclic compounds formed by carbon. This structure provides a large micropore volume and a high specific surface area, enabling the activated carbon filter 91 to deodorize, adsorb color, and adsorb chlorine. In the present invention, no chemicals need to be added to the hydrofluoric acid wastewater 901 during its passage from the wastewater collection tank 90 to the activated carbon filter 91. Organic constituents in the hydrofluoric acid wastewater 901 are removed by the adsorption properties of the activated carbon filter 91. This adsorption includes physical adsorption, such as adsorption by van der Waals force, chemical bonding, or surface electrostatic charge attraction. Residual oxidizing disinfectants in the hydrofluoric acid wastewater 901 are removed by catalysis with activated carbon to produce first wastewater 911 .

[0018] 1 and 2 , a capacitive deionization device 92 communicates with an activated carbon filter 91. The capacitive deionization device 92 filters a first wastewater 911 to form a high-concentration fluoride wastewater 922 and a low-concentration fluoride wastewater 921. The capacitive deionization device 92 is connected to a low-concentration collection tank 60 and a high-concentration collection tank 30, respectively. The capacitive deionization device 92 may be a CDI (Capacitive Deionization) or a Membrane Capacitive Deionization (MCDI) device. This embodiment is a thin-film capacitive deionization device, but is not limited to this. The capacitive deionization device 92 has multiple electrodes. When an external voltage is applied between the multiple electrodes, an electrostatic field is formed. When the first wastewater 911 enters the electrostatic field, charged ions in the first wastewater 911 are affected by Coulomb force and move toward corresponding electrodes of opposite charge. That is, anions in the first wastewater 911 migrate toward the positively charged electrode, and cations in the first wastewater 911 migrate toward the negatively charged electrode, thereby removing most of the charged ions in the first wastewater 911 and desalination the first wastewater 911. After adsorption is complete, desorption is performed by directly applying an external voltage, and the anions and cations previously adsorbed by the electrostatic field are released back into the first wastewater 911. The capacitive deionization device 92 further includes an exchange membrane attached to the electrodes. This exchange membrane is an anion-cation ion exchange membrane. This exchange membrane blocks the adsorption of co-ions, effectively improving desalination performance. During desorption, it prevents charged ions from adsorbing on the electrodes, completely releases the charged ions adsorbed on the electrodes, protects the electrodes, and reduces redox reactions occurring on the electrodes. As can be seen, the capacitive deionization device 92 has advantages such as low pretreatment requirements, simple equipment maintenance, low energy consumption, and high recovery rate. In this embodiment, the first wastewater 911 enters the capacitive deionization device 92, and the electrostatic field causes the fluoride ions and hydrogen ions in the first wastewater 911 to migrate toward corresponding electrodes of opposite charge, thereby forming the first wastewater 911 into low-concentration fluoride wastewater 921.In one embodiment, the fluoride ion concentration in the low-concentration fluoride wastewater 921 is 50 mg / L. After a certain period of time has passed, an external voltage is applied, causing fluoride ions and hydrogen ions to be desorbed and released from the multiple electrodes, thereby converting the first wastewater 911 into high-concentration fluoride wastewater 922. In one embodiment, the fluoride ion concentration in the high-concentration fluoride wastewater 922 is 10,000 mg / L. The low-concentration fluoride wastewater 921 and the high-concentration fluoride wastewater 922 are directed to different devices, with the low-concentration fluoride wastewater 921 being collected by the low-concentration collection tank 60 and the high-concentration fluoride wastewater 922 being collected by the high-concentration collection tank 30.

[0019] 1 and 2. As shown in FIGS. 1 and 2, the low-concentration collection tank 60 collects low-concentration fluoride wastewater 921. The low-concentration collection tank 60 is connected to a filtration device 80. The filtration device 80 may be connected to the low-concentration collection tank 60 alone, to the wastewater collection tank 90, or to both the low-concentration collection tank 60 and the wastewater collection tank 90, but this is not limitative. One or more filtration devices 80 may be connected to increase the total recovery rate or the purity of the produced water. The connection of multiple filtration devices 80 may be a multi-stage system to increase the total recovery rate or a multi-pass system to increase the purity of the produced water. The filtration device 80 may be a reverse osmosis (RO) device or a thin-film capacitive deionization device. In this embodiment, the filtration device 80 is a reverse osmosis device. After flowing toward the filtration device 80, the low-concentration fluoride wastewater 921 forms recovered water 801 and second wastewater 802. The reverse osmosis device selects a semipermeable membrane pore size of 0.0001 to 0.001 μm and applies pressure. In this embodiment, the semipermeable membrane pore size is 0.001 μm, resulting in recovered water 801 from which impurities other than water molecules have been almost completely removed. The impurities may be, for example, metal ions, soluble salts, inorganic molecules, mineral matter, or organic matter. In one embodiment, the fluoride ion concentration in the recovered water 801 is less than 5 mg / L. The recovered water 801 is returned to the factory for internal reuse, achieving water reuse. Here, the recovered water 801 can be re-entered into a second filtration device 80, and multiple filtration devices 80 can be used to increase the water recovery rate and salt removal rate of the recovered water 801, but this is not limited to this. The second wastewater 802 is wastewater that does not pass through the filtration device 80. The second wastewater 802 may be recovered by returning it to the wastewater collection tank 90 or the low-concentration collection tank 60.

[0020] Please refer to FIGS. 1 to 3. As shown in FIGS. 1 to 3, the high-concentration collection tank 30 collects high-concentration fluorine wastewater 922. The high-concentration collection tank 30 is connected to a reaction device 10. The reaction device 10 is connected to a dehydration device 50. The reaction device 10 and the dehydration device 50 may be the same device or different devices, and in this embodiment, they are different devices, but are not limited to this. Please also refer to FIGS. 3 and 4. As shown in FIGS. 3 and 4, the present invention will further describe in detail the technical means adopted to achieve the specified object of the invention. More specifically, one end of the reaction device 10 in this embodiment is connected to a sodium aluminate chemical tank 20, and an aluminum-containing compound is added to the sodium aluminate chemical tank 20.

[0021] Please refer to Fig. 3. As shown in Fig. 3, in this embodiment, the sodium aluminate chemical tank 20 has a level meter 21 and a discharge valve 26. A batch quantitative control section 201 of the sodium aluminate chemical tank 20 has a transfer pump 22. Two ball valves 23 and 24 are provided between the transfer pump 22 and the sodium aluminate chemical tank 20 and between the transfer pump 22 and the reactor 10, respectively. The batch quantitative control section 201 has a sodium aluminate flow meter 25 provided adjacent to the reactor 10, and the level meter 21, the transfer pump 22, the two ball valves 23 and 24, the sodium aluminate flow meter 25, and the discharge valve 26 are electrically controlled by a control processor A.

[0022] Referring to Figure 3, as shown in Figure 3, the reactor 10 has a top tank port 11 and a bottom outlet 12 corresponding to each other. Inside the reactor 10, there is a distributor 13 having a plurality of liquid holes 131, and a control panel 14 located on the distributor 13 and having a plurality of through-holes 141. Inside the reactor 10, the distributor 13 and the control panel 14 installed at an interval form an upper dosing space 101 and a lower reaction space 102. The upper dosing space 101 has a sodium aluminate level meter 15. The lower reaction space 102 communicates with a discharge control section 16 via the bottom outlet 12. The sodium aluminate level meter 15 and the discharge control section 16 are electrically controlled by a control processor A. In this embodiment, the lower reaction space 102 of the reaction apparatus 10 has a hydrofluoric acid level gauge 17 electrically controlled by the control processor A, and in order to detect the liquid level of the high-concentration fluoride wastewater 922 in the lower reaction space 102, the control processor A electrically controls the flow rates of the aluminum sodium-containing compound and the high-concentration fluoride wastewater 922 output from the sodium aluminate chemical tank 20 and the high-concentration collection tank 30 based on the sodium aluminate level gauge 15 and the hydrofluoric acid level gauge 17. The discharge control section 16 of the reaction apparatus 10 in this embodiment has a flow control valve 161 and a ball valve 162. A discharge flow path 18 is provided between the flow control valve 161 and the bottom outlet 12 of the reaction apparatus 10. The discharge flow path 18 is controlled by a ball valve 181, and the flow control valve 161 and the ball valve 162 of the discharge control section 16 and the ball valve 181 of the discharge flow path 18 are electrically controlled by the control processor A.

[0023] Referring to Figure 3, as shown in Figure 3, the dehydration device 50 is electrically controlled by the control processor A and is in communication with the discharge control section 16 of the reactor 10.

[0024] Please refer to Fig. 3. As shown in Fig. 3, after the high-concentration collection tank 30 collects a certain amount of high-concentration fluorine wastewater 922, it transfers the high-concentration fluorine wastewater 922 into the reaction apparatus 10. The high-concentration collection tank 30 outputs the high-concentration fluorine wastewater 922 into the lower reaction space 102 of the reaction apparatus 10 via a batch quantity control section 301 electrically controlled by a control processor A. In this embodiment, the high-concentration collection tank 30 has a level gauge 31 and a discharge valve 36. The batch quantity control section 301 of the high-concentration collection tank 30 has a transfer pump 32. Two ball valves 33 and 34 are provided between the transfer pump 32 and the high-concentration collection tank 30, and between the transfer pump 32 and the reaction apparatus 10, respectively. The batch quantitative control section 301 is provided with a hydrofluoric acid flow meter 35 adjacent to the reactor 10, and electrically controls the level meter 31, the transfer pump 32, the two ball valves 33 and 34, the hydrofluoric acid flow meter 35, and the discharge valve 36 by the control processor A. In this embodiment, when the high-concentration collection tank 30 collects fluoride ions with a concentration higher than 10,000 mg / L in the high-concentration fluoride wastewater 922, the high-concentration fluoride wastewater 922 is transferred to the reactor 10, but this is not limited to this and can be changed according to the user's needs. By connecting the reactor 10 and the sodium aluminate chemical tank 20, the sodium aluminate chemical tank 20 electrically controls the batch quantitative control section 201 by the control processor A, and outputs an aluminum sodium-containing compound (Sodium Aluminum Compound) into the upper dosing space 101 of the reactor 10. The aluminum sodium-containing compound is specifically sodium aluminate, and compounds containing fluoride ions and fluorine in the high-concentration fluoride wastewater 922 are mixed with the aluminum sodium-containing compound to form a mixed water sample. The mixed water sample reacts to produce cryolite 103 (NaAlF) and third wastewater 501 (see the following formula (I)). The dehydration device 50 separates the precipitated cryolite 103 and the third wastewater 501, and sends the third wastewater 501 to a waste liquid tank 81 or a conventional wastewater treatment system. The dehydration device 50 is connected to the waste liquid tank 81. The waste liquid tank 81 is electrically controlled by the control processor A and collects the third wastewater 501 discharged from the dehydration device 50.In this embodiment, a ball valve 811 that controls the flow rate of the third wastewater 501 is provided between the waste liquid tank 81 and the dehydration device 50. The waste liquid tank 81 has a level meter 812, a discharge valve 813, and a low-concentration fluoride wastewater output section 814. The low-concentration fluoride wastewater output section 814 has a transport pump 815 and two ball valves 816 and 817. One ball valve 816 is provided between the transport pump 815 and the waste liquid tank 81, and the other ball valve 817 is provided at the discharge end of the transport pump 815 that connects to the low-concentration fluoride wastewater output section 814, and the level meter 812, the discharge valve 813, the transport pump 815, and the three ball valves 811, 816, and 817 are electrically controlled by a control processor A. Therefore, the high-concentration fluoride wastewater 922 is a favorable environment for the crystallization of cryolite 103, since it provides a source of sodium ions and aluminum ions that form the crystals of cryolite 103 provided by the aluminum sodium-containing compound.

[0025] [ka]

[0026] 3 and 4. As shown in FIGS. 3 and 4, the pH value / fluoride ion detection section 40 of this embodiment includes a pH meter 41 electrically controlled by a control processor A, and a fluorometer 42. The pH meter 41 and the fluorometer 42 are connected to each other via a tubing. The pH meter 41 has a first flow path 43 that communicates with the bottom of the lower reaction space 102 of the reaction device 10. The first flow path 43 includes a measuring pump 431. Two ball valves 433 and 434 are provided between the measuring pump 431 and the reaction device 10, and between the measuring pump 431 and the pH meter 41, respectively. In this embodiment, a clean water input section 46 is provided between the measuring pump 431 and the pH meter 41. The purified water input section 46 has a flow control valve 461 for controlling the amount of purified water input, and the amount of purified water to be injected is controlled in advance. The pH value and fluoride ion content of the mixed water sample are detected via the pH meter 41 and fluorometer 42. If the detection is complete and the mixed water sample fails, the second flow path 44 connecting the fluorometer 42 to the top of the lower reaction space 102 is used to control the mixed water sample after detection to be returned to the reaction device 10 via the reflux control valve 441 of the second flow path 44. If the mixed water sample passes, the mixed water sample is discharged to the dehydrator 50 via the third flow path 45 connecting the fluorometer 42 to the dehydrator 50 via the discharge control valve 451 and ball valve 452 of the third flow path 45. The dehydrator 50 is connected to the third flow path 45 of the pH / fluoride ion detection section 40 and discharges waste liquid after the pH / fluoride ion detection section 40 has been cleaned. The terminal opening of the second flow path 44, which communicates with the interior of the reaction device 10, is provided from the upper tank wall of the lower reaction space 102 of the reaction device 10 to the center of the upper tank of the lower reaction space 102, and preferably, the second flow path 44 extends and communicates with the upper center of the lower reaction space 102 via a pipe 442, thereby minimizing the impact caused when the mixed water sample returns.

[0027] Please refer to Fig. 3. As shown in Fig. 3, in order to ensure the measurement accuracy of the pH meter 41 and the fluorometer 42, the pH value / fluoride ion detection section 40 utilizes a clean water input section 46 to wash the pH meter 41 and the fluorometer 42 with the input clean water, which is then discharged to the dehydration device 50 via a third flow path 45. The measurement pump 431, two flow control valves 432, 461, three ball valves 433, 434, 452, and discharge control valve 451 of the pH value / fluoride ion detection section 40 are electrically controlled by a control processor A. The equipment of the present invention further communicates with the second flow path 44 and the discharge control section 16 via a fourth flow path 48, and a seed crystal storage tank 47 and a transport pump 481 are installed in the fourth flow path 48, so that when the mixed water sample flows back from the discharge control section 16 to the second flow path 44 via the fourth flow path 48 and enters the reactor 10, seed crystals can be introduced into the reactor 10 through the seed crystal storage tank 47, completing the transplantation step, promoting the crystallization reaction to increase the crystal particle size, and improving the crystal quality of the cryolite 103.

[0028] 5 to 9. As shown in FIGS. 5 to 9, in the present invention, the distributor 13 and the control panel 14 in the reactor 10 are formed in a disk shape. The plurality of liquid holes 131 in the distributor 13 are formed in a U-shaped radial pattern from the center of the circle. The plurality of through holes 141 in the control panel 14 are composed of a first through hole group 14a, a second through hole group 14b, and a third through hole group 14c. The first through hole group 14a, the second through hole group 14b, and the third through hole group 14c are formed in a U-shaped radial pattern from the center of the circle of the control panel 14, and an angle θ is formed between adjacent radial directions. The first through hole group 14a has the same number of through holes 141 as the liquid holes 131 in the distributor 13. The second through hole group 14b and the third through hole group 14c have different numbers of through holes 141, each of which is smaller than the number of liquid holes 131 in the distributor 13.

[0029] In this embodiment, the distributor 13 further has a plurality of positioning holes 132. The control panel 14 has three sets of position restraint holes 142 corresponding to the positions and number of the positioning holes 132 of the distributor 13. An angle θ is formed between each set of position restraint holes 142, and one set of position restraint holes 142 of the control panel 14 is aligned with the positioning holes 132 of the distributor 13, and a plurality of positioning pins (not shown) corresponding to the number of the positioning holes 132 are inserted into the positioning holes 132 of the distributor 13 and the position restraint holes 142 of the control panel 14, and the liquid holes 131 of the distributor 13 and the through holes 141 of the control panel 14 are aligned and fixed, thereby ensuring the flow rate and liquid flow pattern of the aluminum sodium-containing compound.

[0030] Other features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with FIGS.

[0031] In this embodiment, a wastewater collection tank 90 is connected to an activated carbon filter 91. Hydrofluoric acid wastewater 901 is collected and stored in the wastewater collection tank 90 in advance. The fluoride ion concentration of the hydrofluoric acid wastewater 901 is 1000 mg / L. The hydrofluoric acid wastewater 901 is then passed through the activated carbon filter 91, where the activated carbon in the activated carbon filter 91 adsorbs and removes soluble or persistent organic matter, chlorine gas, odors, and other substances contained in the hydrofluoric acid wastewater 901. The adsorption of chlorine gas can cause problems such as oxidation or organic scale in the subsequent capacitive deionization device 92 or filter 80, and the first wastewater 911 is filtered by the activated carbon filter 91. The activated carbon filter 91 is connected to a capacitive deionization device 92. The first wastewater 911 flows into the capacitive deionization device 92, which rapidly adsorbs ions in the solution of the first wastewater 911 through electrochemical and physical adsorption, forming low-concentration fluoride wastewater 921. The fluoride ion concentration in the low-concentration fluoride wastewater 921 is 50 mg / L. When the electric field is removed, the ions adsorbed on the electrode surface are desorbed, forming high-concentration fluoride wastewater 922. The fluoride ion concentration in the high-concentration fluoride wastewater 922 is 10,000 mg / L. The capacitive deionization device 92 is connected to the high-concentration collection tank 30 and the low-concentration collection tank 60, respectively. The low-concentration fluoride wastewater 921 flows toward the low-concentration collection tank 60, and the high-concentration fluoride wastewater 922 flows toward the high-concentration collection tank 30. The low-concentration collection tank 60 is connected to the filtration device 80. The filtration device 80 is connected to the wastewater collection tank 90. The low-concentration fluorine wastewater 921 flows toward the filtration device 80, where, due to the pore size of the semipermeable membrane, the permeability characteristics of water molecules, and pressurization, second wastewater 802 and recovered water 801, which has good water quality and can be directly discharged or recovered and reused, are obtained. The second wastewater 802 can be returned to the wastewater collection tank 90. ​​The high-concentration collection tank 30 is connected to the reactor 10. The reactor 10 is connected to the dehydration device 50. The high-concentration fluorine wastewater 922 flows toward the reactor 10. The sodium aluminate chemical tank 20 adds an aluminum sodium-containing compound to the reactor 10. In this embodiment, the aluminum sodium-containing compound is an aqueous solution of sodium aluminate (NaAlO2) with a concentration of approximately 35 to 45 wt %.Based on the concentration of hydrofluoric acid in the high-concentration fluorine wastewater 922, an aluminum sodium-containing compound is added according to the ratio in formula (I). Since the high-concentration fluorine wastewater 922 in the reactor 10 contains sufficient fluoride ions, the sodium ions and aluminum ions of the sodium aluminate undergo a chemical reaction. The high-concentration fluorine wastewater 922 is mixed with the aluminum sodium-containing compound to form a mixed water sample. The mixed water sample is detected and monitored by the pH / fluoride ion detection section 40. After the reaction is complete, cryolite 103 and other similar precipitates are produced. The cryolite 103 and third wastewater 501 are then separated via the dehydration device 50 and wastewater tank 81, yielding cryolite 103 with uniform particle size and high purity. Cryolite 103 may be used as an industrial raw material such as a chemical raw material, a flux for glass and ceramic manufacturing, a flux for aluminum electrolysis manufacturing, an anti-wear additive for abrasive products, an anti-wear filler for resin or rubber, a flux for the steel industry, an electrolyte for ferroalloy boiling steel production, an additive for building materials, etc. Here, the reactor 10 is cooled after the reaction to lower the temperature of the third wastewater 501 to 40°C or less, but this is not limited thereto.

[0032] As can be seen from the above, the hydrofluoric acid wastewater recovery system according to the present invention, capable of extracting industrial raw materials, uses activated carbon filtration device 91 to initially purify hydrofluoric acid wastewater 901, and then uses capacitive deionization device 92 to demineralize first wastewater 911, concentrating and recovering fluoride ions in first wastewater 911. Furthermore, the electrodes are regenerated by discharging the capacitive deionization device 92, eliminating the need to add chemicals or adjust the pH value. Furthermore, since the electrodes are adsorbed and desorbed and the exchange membrane is provided, the ions desorbed from the electrodes are adsorbed on the opposing electrodes, forming colloids and scale. The high-concentration fluorine wastewater 922 is introduced into the reactor 10, and an aluminum sodium-containing compound is added via the sodium aluminate chemical tank 20 for reaction, resulting in the precipitation of cryolite 103, an industrial raw material with economic value. The low-concentration fluorine wastewater 921 is then filtered via the filtration device 80 to obtain recycled water 801 of good quality that can be recycled to the factory. The present invention not only efficiently removes fluoride ions from the hydrofluoric acid wastewater 901, but also provides the industrial raw material cryolite 103 and recycled water 801 that can be recovered and reused, thereby protecting the environment and reducing wastewater treatment costs.

[0033] The above mainly describes the connection relationships between the devices and their valves of this system facility, and the assembly relationships of the distribution panel 13 and control panel 14. Below, as shown in Figures 3 to 10, devices such as a plurality of valves, level gauges, flow meters, pumps, pH meters, and fluorometers of the present invention are electrically connected to a control processor A, and form a control method in which they are electrically controlled by the control processor A. This control method may be automatic or manual, and includes the following steps (S1) to (S6).

[0034] Step (S1): Parameter setting The control processor A sets the parameter items and their numerical ranges shown in Table 1. However, the parameter items are not limited to those shown in Table 1, and the parameter settings may be increased or decreased according to the needs of actual operation. After the parameter setting step of step (S1) is completed, the distributor 13 and the control panel 14 are installed according to the flow rate needs of the aluminum sodium-containing compound, and the flow rate at which the aluminum sodium-containing compound falls into the lower reaction space 102 is controlled.

[0035] [Table 1]

[0036] Step (S2): Injection of high-concentration fluoride wastewater The batch quantitative control section 301 of the high-concentration collection tank 30 is started, and the high-concentration fluorine wastewater 922 is input into the lower reaction space 102 of the reactor 10 based on the set value of the parameter setting step (S1).

[0037] Step (S3): Addition of aluminum sodium-containing compound After the high-concentration fluorine wastewater 922 has been completely injected into the reactor 10, the batch quantity control section 201 of the sodium aluminate chemical tank 20 is started, and the aluminum sodium-containing compound is input into the upper dosing space 101 of the reactor 10 according to the set value in the parameter setting step (S1). In this step, in a preferred implementation state, when the batch quantity control section 201 of the sodium aluminate chemical tank 20 is started, the time for inputting the aluminum sodium-containing compound is simultaneously started and recorded according to the set value in the parameter setting step (S1).

[0038] Step (S4): Allow the mixed water sample to stand Based on the set values ​​in the parameter setting step (S1), calculation of the reaction settling time is started. In this step, preferably, after the sodium aluminum-containing compound is batch-output from the sodium aluminate chemical tank 20, timing is started when the low liquid level of the level gauge 21 is reached, and the reaction is settling.

[0039] Step (S5): Supply the mixed water sample to the pH / fluoride ion detection section. When the reaction static time is over, the measuring pump 431 and the flow control valve 432 of the pH value / fluoride ion detection section 40 are started, and the mixed water sample in the reactor 10 is introduced into the pH value / fluoride ion detection section 40. This step further includes simultaneously carrying out a step (S51) of reading the pH values ​​and fluoride ion concentrations of the high-concentration fluoride wastewater 922 and the mixed water sample, and a step (S52) of returning the mixed water sample to the reactor. That is, the mixed water sample flows through the pH meter 41 and the fluorometer 42, and while the pH value and fluoride ion concentration are being read, the mixed water sample is controlled by the valve to flow from the bottom outlet 12 of the reactor 10 through the discharge control section 16, enter the fourth flow path 48, flow through the seed crystal storage tank 47, and introduce the seed crystal into the reactor 10 through the second flow path 44.

[0040] Step (S6): Determine the reaction end point The reaction endpoint is determined using the pH value and fluoride ion concentration of the mixed water sample. If the reaction has not yet reached the endpoint, the pH / fluoride ion detection section closing step (S61) and the aluminum sodium-containing compound fine-tuning step (S62) are performed. Based on the parameters set in the parameter setting step (S1), a trace amount of aluminum sodium-containing compound is input into the reaction device 10 at the pH value read. The following steps are repeated until the reaction reaches the endpoint: inputting aluminum sodium-containing compound (S3), allowing the mixed water sample to stand (S4), supplying the mixed water sample to the pH / fluoride ion detection section (S5), and determining the reaction endpoint (S6). The pH value and the amount of aluminum sodium-containing compound added in the aluminum sodium-containing compound fine-tuning step (S62) are determined according to the corresponding values ​​in Table 2, but are not limited thereto; the corresponding values ​​may be adjusted according to actual operation.

[0041] [Table 2]

[0042] Step (S7): Solid-liquid separation The dehydrator 50 and the discharge control section 16 of the reactor 10 are activated to perform the discharge step. More specifically, when the reaction reaches the reaction end point, the dehydrator 50 and the discharge control section 16 of the reactor 10 are activated, and then the crystallized material dehydration and collection step (S71) and the third wastewater discharge step (S72) are performed. After completion of these steps, the discharge control section of the reactor is closed (S73). In this step, the dehydrator 50 preferably reaches a predetermined rotation speed before performing the crystallized material dehydration and collection step (S71), causing the cryolite 103 to flow into the dehydrator 50 by gravity. The shaken-off third wastewater 501 flows into the waste liquid tank 81 by gravity, completing the third wastewater discharge step (S72), the cryolite 103 remaining in the filter cloth of the dehydrator 50, completing the crystallized material dehydration and collection step (S71), and finally closing the discharge control section 16 of the reactor 10.

[0043] Step (S8): Automatic mode determination The control processor A presets the current operation to automatic mode or manual mode. If it is in automatic mode, the control processor A automatically controls the system, starting from the high-fluoride wastewater injection step (S2) and repeating the steps described above. If it is in manual mode, the control processor A stops the automatic control and returns to the parameter setting step (S1), and after completing the parameter setting, starts the automatic control.

[0044] According to the present invention described above, when the fluoride ion concentration in the high-concentration fluoride wastewater 922 is 10-500 g / L, the standing time is 10-200 minutes, and the reaction end point pH value is 2-10, the fluoride ion concentration in the third wastewater 501 discharged after the reaction drops to 20 g / L or less, and the fluoride content in the third wastewater 501 can be effectively removed. Table (3) below lists five examples to illustrate the operation control parameters and related analytical data of the equipment for producing cryolite 103 from high-concentration fluoride wastewater 922 according to the present invention.

[0045] [Table 3]

[0046] The distributor 13 and control panel 14 in the reactor 10 control the liquid flow pattern and flow rate during the contact reaction between the aluminum sodium-containing compound and the high-concentration fluoride wastewater 922, and the pH value / fluoride ion detection section 40, which is in a loop configuration and connected to the reactor 10, monitors the pH value and fluoride ion concentration of the high-concentration fluoride wastewater 922 and the mixed water sample, effectively controlling factors affecting the crystalline purity of the cryolite 103 during the reaction process, so that the system stably forms crystalline pure cryolite 103 that can be recycled and reused, thereby increasing the recovery rate of fluoride ions and improving the crystalline purity of the cryolite 103 produced, which is highly economical.

[0047] Although the preferred embodiments of the present invention have been disclosed above so that those skilled in the art can understand, they are not intended to limit the present invention in any way. Various changes and modifications can be made within the scope of the present invention. Therefore, the scope of the claims of the present invention should be broadly interpreted to include such changes and modifications. [Explanation of symbols]

[0048] 10. Reactor 11 Top tank mouth 12 Bottom outlet 13 Dispersion board 14 Control Panel 14a First through-hole group 14b Second group of through holes 14c Third group of through holes 15 Sodium aluminate level gauge 16 Emissions Control Section 17 Hydrofluoric acid level gauge 18 Exhaust flow path 20 Sodium aluminate chemical tank 21 Liquid level gauge 22 Transport pump 23 Ball Valve 24 Ball Valve 25 Sodium aluminate flow meter 26 Exhaust valve 30 High concentration collection tank 31 Liquid level gauge 32 Transport pump 33 Ball Valve 34 Ball Valve 35 Hydrofluoric Acid Flow Meter 36 Exhaust valve 40 pH / fluoride ion detection section 41 pH meter 42 Fluorometer 43 First Channel 44 Second Channel 45 Third Stream 46 Clean Water Input Section 47 Seed crystal storage tank 48 Fourth Stream 50 Dehydration equipment 60 Low concentration collection tank 70 Overflow Prevention Base 71 Overflow prevention body 72 Leak detection equipment 73 Drain valve 80 Filtration device 81 Waste liquid tank 90 Wastewater collection tank 91 Activated carbon filtration device 92 Capacitive Deionizer 101 Upper medication space 102 Lower reaction space 103 Cryolite 131 Liquid pore 132 Positioning hole 141 Through hole 142 Position restriction hole 161 Flow control valve 162 Ball Valve 181 Ball Valve 201 Batch Quantitative Control Section 301 Batch Quantity Control Section 431 Measuring Pump 432 Flow Control Valve 433 Ball Valve 434 Ball Valve 441 Reflux control valve 442 Tube 451 Discharge Control Valve 452 Ball Valve 461 Flow Control Valve 481 Transport Pump 501 Tertiary Wastewater 801 Reclaimed Water 802 Secondary wastewater 811 Ball Valve 812 Liquid level gauge 813 Discharge valve 814 Low-concentration fluoride wastewater output section 815 Transport pump 816 Ball Valve 817 Ball Valve 901 Hydrofluoric acid wastewater 911 First Wastewater 921 Low-concentration fluoride wastewater 922 High-concentration fluoride wastewater A Control Processor

Claims

1. A hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials, comprising a wastewater collection tank, an activated carbon filtration device, a capacitive deionization device, a low-concentration collection tank, at least one filtration device, a high-concentration collection tank, a reactor, and a dehydration device, the wastewater collection tank contains hydrofluoric acid wastewater; the activated carbon filtration device is connected to the wastewater collection tank and filters the hydrofluoric acid wastewater to produce a first wastewater; the capacitive deionizer is connected to the activated carbon filter and has a plurality of oppositely charged electrodes; causing ions in the first wastewater to migrate toward a plurality of corresponding electrodes of opposite charge to form a low-fluoride wastewater; By desorbing and releasing ions from multiple electrodes, high-concentration fluoride wastewater is formed. the low-concentration collection tank is connected to the capacitive deionization device and stores low-concentration fluoride wastewater; the filtration device is connected to the low-concentration collection tank and filters the low-concentration fluoride wastewater to form recovered water, which is returned to the factory for internal reuse; the high-concentration collection tank is connected to the capacitive deionization device and stores the high-concentration fluoride wastewater; the reactor is connected to the high-concentration collection tank, and generates cryolite and a third wastewater by reacting the added aluminum sodium-containing compound with the high-concentration fluoride wastewater; a dehydration device connected to the reaction device and separating the cryolite from the third wastewater;

2. The capacitive deionization device is a CDI (Capacitive De-Ionization) or thin film capacitive deionization device; 2. The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to claim 1, wherein the aluminum sodium-containing compound is sodium aluminate.

3. the ions in the first wastewater include fluoride ions and hydrogen ions; the fluoride ion concentration in the high-fluoride concentration wastewater is higher than the fluoride ion concentration in the low-fluoride concentration wastewater, 2. The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to claim 1, wherein the fluoride ion concentration in the high-concentration fluoride wastewater is higher than the fluoride ion concentration in the hydrofluoric acid wastewater.

4. The filtration device is connected to the wastewater collection tank, the low-concentration collection tank, or both the low-concentration collection tank and the wastewater collection tank; 2. The hydrofluoric acid wastewater recovery system according to claim 1, wherein the filtration device is a reverse osmosis (RO) device or a thin film capacitive deionization device.

5. further comprising a control processor; The reactor has a top vessel inlet and a bottom outlet corresponding to each other, The reactor is provided with a distributor having a plurality of liquid holes therein, and a control panel located on the distributor and having a plurality of through-holes therein, The distributor and the control panel are installed at an interval inside the reactor, forming an upper dosing space and a lower reaction space; the upper dosage space has a sodium aluminate level indicator; The lower reaction space communicates with the discharge control section through the bottom outlet, and discharges a mixed water sample formed by the aluminum sodium-containing compound and the high-concentration fluoride wastewater; reacting the mixed water sample to produce the cryolite and the third wastewater; the sodium aluminate level meter and the discharge control section are electrically controlled by the control processor; the discharge control section is connected to the dehydration device and the waste liquid tank to separate the cryolite and the third waste water; the dehydration device and the waste liquid tank are electrically controlled by the control processor; the dehydration device is in communication with the discharge control section of the reactor; 2. The hydrofluoric acid wastewater recovery system according to claim 1, wherein the waste liquid tank collects the third wastewater discharged from the dehydration device.

6. the lower reaction space of the reactor has a hydrofluoric acid level gauge electrically controlled by the control processor; the discharge control section of the reactor includes a flow control valve and a ball valve; a discharge passage between the flow control valve and the bottom outlet of the reactor; the discharge flow path is controlled by the ball valve; the flow control valve and the ball valve of the discharge control section and the ball valve of the discharge flow path are electrically controlled by the control processor; Further comprising a sodium aluminate chemical bath and a pH value / fluoride ion detection section; The sodium aluminate chemical tank is electrically controlled by the control processor through a batch quantity control section, and the sodium aluminum compound is added into the upper dosage space of the reactor; the pH value / fluoride ion detection section has a pH meter and a fluorometer that are electrically controlled by the control processor and communicate with each other, supplies the mixed water sample to the pH meter and the fluorometer, and detects the pH value and fluoride content of the mixed water sample discharged by the discharge control section; the pH meter has a first flow path communicating with the bottom of the lower reaction space of the reactor; 6. The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to claim 5, wherein the fluorometer has a second flow path communicating with the top of the lower reaction space, and the mixed water sample is returned to the reaction device or discharged.

7. The plurality of liquid holes of the distributor are formed in a U-shaped radial pattern from the center of a circle, the plurality of through holes of the control panel are composed of a first through hole group, a second through hole group, and a third through hole group, the first through hole group, the second through hole group, and the third through hole group are formed in a U-shaped radial pattern from the center of the control panel, and an angle is formed between adjacent radial directions, the first through-hole group has the same number of through-holes as the number of liquid holes of the distributor, The second through-hole group and the third through-hole group have a different number of through-holes than the number of the liquid holes of the distributor, The distributor has a plurality of positioning holes, The control panel has three sets of position restraint holes corresponding to the positions and number of the positioning holes of the distribution panel, and an angle is formed between the position restraint holes of each set, The set of position restraint holes of the control panel and the positioning holes of the distribution panel can be aligned, 6. The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to claim 5, wherein the distribution board and the control board are fixed by inserting a plurality of positioning pins, the number of which corresponds to the number of the positioning holes.

8. the high-concentration collection tank has a level gauge and a discharge valve; the batch quantity control section of the high concentration collection tank has a transfer pump; two ball valves are provided between the transfer pump and the high-concentration collection tank and between the transfer pump and the reaction device, respectively; the batch quantitative control section of the high-concentration collection tank is provided with a hydrofluoric acid flow meter adjacent to the reactor; In the high-concentration collection tank, the level meter, the transfer pump, the two ball valves, the hydrofluoric acid flow meter, and the discharge valve are electrically controlled by the control processor; The sodium aluminate chemical tank has a level gauge and a discharge valve, the batch quantity control section of the sodium aluminate chemical tank has a transfer pump; Two ball valves are provided between the transfer pump and the sodium aluminate chemical tank and between the transfer pump and the reactor, respectively; The batch quantitative control section of the sodium aluminate chemical tank is provided with a sodium aluminate flow meter adjacent to the reactor, In the sodium aluminate chemical tank, the level meter, the transfer pump, the two ball valves, the sodium aluminate flow meter, and the discharge valve are electrically controlled by the control processor; the first flow path of the pH / fluoride ion detection section has a measurement pump; a flow control valve and a ball valve are provided between the reaction device and the measuring pump; a ball valve and a clean water input section are provided between the measuring pump and the pH meter; the clean water input section has a flow control valve for controlling the amount of clean water input; the second flow path has a reflux control valve; the fluorometer has a third flow path; the third flow path has a discharge control valve and a ball valve to control the discharge of the waste liquid; In the pH value / fluoride ion detection section, the measuring pump, the two flow control valves, the three ball valves, and the discharge control valve are electrically controlled by the control processor; an end opening of the second flow path communicating with the interior of the reaction device is provided from an upper tank wall of a lower reaction space of the reaction device to a center of the upper tank of the lower reaction space; the waste liquid tank has a level gauge, a discharge valve, and a low-concentration fluorine wastewater output section; a ball valve for controlling the flow rate of the third wastewater is provided between the waste liquid tank and the dehydration device; the low-concentration fluorine wastewater output section has a transfer pump and two ball valves, one of which is provided between the transfer pump and the waste liquid tank and the other of which is provided at the discharge end of the transfer pump connected to the wastewater output section; 7. The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to claim 6, wherein in the waste liquid tank, the level meter, the discharge valve, the transfer pump, and the three ball valves are electrically controlled by the control processor.

9. The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to claim 6 is installed on an overflow prevention base, An overflow prevention body is provided on the periphery of the overflow prevention base, and the overflow prevention body has a leak detection device electrically controlled by the control processor and a drain valve provided at the bottom of the overflow prevention base, Further comprising a seed crystal reservoir; the seed crystal storage tank stores seed crystals therein and is installed in the fourth flow path; the fourth flow path communicates with the reactor and the discharge control section thereof; a transfer pump is installed between the seed crystal storage tank and the discharge control section; 7. The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to claim 6, wherein the fourth flow path guides the mixed water sample discharged from the discharge control section to the seed crystal storage tank and then returns it to the reactor, and introduces the seed crystals into the reactor.

10. the control processor executes a control method including a parameter setting step, a high-concentration fluoride wastewater injection step, an aluminum sodium-containing compound addition step, a step of allowing the mixed water sample to stand, a step of supplying the mixed water sample to the pH value / fluoride ion detection section, a reaction end point determination step, and a solid-liquid separation step; In the parameter setting step, the control processor sets parameter items and numerical ranges of the parameter items, and installs the distributor and the control panel based on the flow rate needs of the aluminum-sodium-containing compound to control the flow rate of the aluminum-sodium-containing compound falling into the lower reaction space; In the high-concentration fluorine wastewater injection step, the batch quantitative control section of the high-concentration collection tank is activated, and the high-concentration fluorine wastewater is injected into the lower reaction space of the reactor according to the set values ​​in the parameter setting step; In the aluminum sodium-containing compound adding step, after the high-concentration fluoride wastewater is completely injected into the reactor, the batch quantity control section of the sodium aluminate chemical tank is started, and the aluminum sodium-containing compound is added into the upper dosing space of the reactor according to the set value in the parameter setting step, to form the mixed water sample; In the step of allowing the mixed water sample to stand, calculation of a reaction standing time is started based on the set values ​​in the parameter setting step; In the step of supplying the mixed water sample to the pH value / fluoride ion detection section, when the reaction static time measurement is completed, the pH value / fluoride ion detection section is started, the mixed water sample in the reaction device is supplied to the pH value / fluoride ion detection section, the pH value and the fluoride ion concentration of the mixed water sample are read, and the mixed water sample is returned to the reaction device; In the reaction end point determination step, the control processor determines the reaction end point based on the read pH value and fluoride ion concentration of the mixed water sample, and if the reaction has not reached the reaction end point, performs a pH value / fluoride ion detection section closing step and an aluminum sodium-containing compound fine-tuning step, and adds a trace amount of aluminum sodium-containing compound to the reaction device based on the parameters set in the parameter setting step and the read pH value, and repeats the step of adding aluminum sodium-containing compound, the step of leaving the mixed water sample to stand, the step of supplying the mixed water sample to the pH value / fluoride ion detection section, and the reaction end point determination step until the reaction reaches the reaction end point, 10. The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to claim 9, wherein in the solid-liquid separation step, when the reaction reaches the reaction end point, the discharge control section of the reactor is started, followed by a crystallization dehydration and collection step and a third wastewater discharge step, and after completion of these steps, a step of closing the discharge control section of the reactor is carried out.

11. The control method further includes an automatic mode determination step; said control processor pre-setting the current operation to either an automatic mode or a manual mode; If in automatic mode, automatically control the control processor to start from the step of injecting high-concentration fluoride wastewater and repeatedly execute the steps described above; 11. The hydrofluoric acid wastewater recovery system capable of extracting industrial raw materials according to claim 10, wherein, when in the manual mode, the control processor stops the automatic control, returns to the parameter setting step, and starts the automatic control after the parameter setting is completed.

Images