Impurity removal device and impurity removal method for salt separation crystallization mother liquor of chemical high-salt wastewater

Abstract

The invention discloses an impurity removal device and an impurity removal method for salt separation crystallization mother liquor of chemical high-salt wastewater, and belongs to the technical field of comprehensive utilization of water resources. The impurity removal device comprises a high-density sedimentation tank for receiving high-salinity wastewater salt separation crystallization mother liquor; the first-stage reactor is connected with the high-density sedimentation tank through a pipeline; the second-stage reactor is connected with the first-stage reactor through a pipeline; the three-stage reactor is connected with the filtering device through a pipeline, the filtering device is connected with the mesoporous adsorption tower through a pipeline, the mesoporous adsorption tower is connected with the chelating resin tower through a pipeline, and the chelating resin tower is connected with the modified zeolite adsorption tower through a pipeline. The method has the advantages that equipment configuration is reasonable, and good stability and operability are achieved; the method provided by the invention has outstanding process route originality and low treatment cost, and realizes liquid phase treatment and high-valued cyclic utilization of the chemical high-salinity wastewater salt separation crystallization mother liquor.

Description

Technical Field

[0001] This invention belongs to the field of water resource comprehensive utilization technology, specifically relating to a device for removing impurities from mother liquor of chemical high-salt wastewater desalination crystallization, and also relating to its impurity removal method. Background Art

[0002] The aforementioned high-salinity chemical wastewater refers to the concentrated liquid produced by wastewater from industries such as coal chemical, petrochemical, fine chemical, printing and dyeing, pharmaceutical, pesticide, coking, metallurgy, and phosphate chemical after zero-discharge treatment. It may also include residues from chemical production processes, washing solutions, and material washing liquids, typically with a TDS > 35000 mg / L (sodium sulfate / sodium chloride percentage > 95%). With societal development, the sources of high-salinity chemical wastewater are increasing, and the volume is growing annually. A key challenge is how to achieve high-value recycling and reuse.

[0003] Typically, the treatment of chemical wastewater employs a segmented process. The first segment is zero-discharge treatment, with the main process being: chemical wastewater → pretreatment → biochemical treatment → advanced oxidation → hardening and impurity removal → dual-membrane method, i.e., ultrafiltration (UF)-reverse osmosis (RO) dual-stage membrane separation treatment. The concentrate produced by the reuse of permeate from the dual-membrane method is high-salt wastewater. The second segment is a salt separation and crystallization system (except for small-scale chemical plants), with the main process being: high-salt wastewater → hardening and impurity removal → advanced oxidation → activated carbon adsorption → salt separation (membrane method, cold method, and thermal method combination) crystallization → production of industrial sodium sulfate and sodium chloride.

[0004] The inadequacy of the impurity removal process in the second stage of the process leads to the generation of mother liquor for salt crystallization. The current practice is to dry the mother liquor to produce mixed salts (defined as hazardous waste). For example, the "Environmental Access Conditions for Modern Coal Chemical Construction Projects (Trial)" (December 2015) stipulates that salt sludge generated from wastewater treatment that cannot be utilized as a resource should be temporarily managed as hazardous waste. The output of mixed salts (hazardous waste) is 15-25% of the total salt content in the wastewater, and in some special cases, even exceeds 30% by mass. This hazardous waste is then outsourced for disposal. Since the current outsourcing cost is 1500-2000 yuan / ton, this places a significant economic burden on chemical companies.

[0005] Salt crystallization mother liquor is characterized by its wide range of sources, diverse types, and complex toxic and harmful components, making it difficult to dispose of, costly, and environmentally harmful. It has both environmental and resource attributes. Depending on the chemical products, the composition of the wastewater varies, sometimes significantly, which increases the difficulty of treatment and utilization.

[0006] There are two main existing methods for treating the mother liquor from salt separation and crystallization:

[0007] ① Direct chelation solidification and rigid landfill are possible, but according to the "Solid Waste Pollution Prevention and Control Law" (2020 revision), hazardous waste must be disposed of according to standards. Mother liquor solidification and landfill are now clearly subject to both technical specifications and environmental regulations, and must be strictly implemented in accordance with the new standards.

[0008] ② The mixed salts produced by drying the mother liquor undergo high-temperature pyrolysis (or carbonization) → water washing → advanced oxidation → activated carbon adsorption → salt separation (membrane method, cold method, and hot method combination) and recrystallization → to produce industrial sodium sulfate and sodium chloride. However, the impurity removal technology in this process route belongs to the category of traditional technology, which has defects that lead to the generation of secondary mixed salts (hazardous waste). In addition, it is not economically viable. For example, the equipment investment cost is 10-13 million yuan / ton / hour, and the operating cost is 800-1100 yuan / ton, while the market price of sodium sulfate is about 100 yuan and sodium chloride is about 50 yuan, resulting in a loss-making situation. At the same time, with the gradual promotion of salt separation technology, most chemical industrial clusters have gradually realized the separation of sodium sulfate and sodium chloride, and the output has been increasing year by year, resulting in a continuous decline in market absorption capacity. In some areas, by-product salts are unsold, and even a "reverse subsidy" phenomenon has occurred.

[0009] Therefore, providing a method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization, simplifying the process, reducing costs, achieving cleaner production, and realizing liquid-phase treatment and high-value utilization, has become an urgent problem for those skilled in the art. Of course, considering the principle that "a good workman must first sharpen his tools," a reasonably configured, inexpensive, and easy-to-operate impurity removal device for the mother liquor of high-salt chemical wastewater desalination crystallization is an indispensable condition for ensuring the smooth implementation of the impurity removal method and achieving good impurity removal results. Summary of the Invention

[0010] The objective of this invention is to provide a device for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization, which has a reasonable equipment configuration and good economic efficiency and operability.

[0011] Another objective of this invention is to provide a method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization. This method has outstanding originality in its process route, optimized treatment flow, low treatment cost, and can meet the excellent resource utilization requirements of turning waste into treasure.

[0012] The objective of this invention is achieved as follows: a device for removing impurities from the mother liquor of high-salt chemical wastewater undergoing desalination crystallization includes a high-density sedimentation tank for receiving the mother liquor; a primary reactor connected to the high-density sedimentation tank via a pipeline; a secondary reactor connected to the primary reactor via a pipeline; and a tertiary reactor connected to a filtration device via a pipeline, the filtration device being connected to a mesoporous adsorption tower via a pipeline, the mesoporous adsorption tower being connected to a chelating resin tower via a pipeline, and the chelating resin tower being connected to a modified zeolite adsorption tower via a pipeline.

[0013] In a specific embodiment of the present invention, the high-density sedimentation tank comprises, from left to right, a high-density sedimentation tank conditioning zone, a high-density sedimentation tank coagulation zone, a high-density sedimentation tank flocculation zone, and a high-density sedimentation tank sedimentation zone, all connected in sequence; the primary reactor comprises, from left to right, a primary reactor conditioning zone, a primary reactor micro-electric field treatment zone equipped with a sludge scraper, a primary reactor sludge storage zone, and a primary reactor sedimentation zone, all connected in sequence, with the bottom of the primary reactor micro-electric field treatment zone and the bottom of the primary reactor sedimentation zone connected by a bottom sludge return pipe; the secondary reactor comprises, from left to right, a secondary reactor conditioning zone, a secondary reactor micro-electric field treatment zone, and a secondary reactor sedimentation zone, all connected in sequence, with the bottom of the secondary reactor micro-electric field treatment zone and the bottom of the secondary reactor sedimentation zone connected by a bottom sludge return pipe; the tertiary reactor comprises, from left to right, a first-stage conditioning zone, a tertiary reactor micro-electric field treatment zone, a second-stage conditioning zone, a tertiary reactor sedimentation zone, a third-stage conditioning zone, and a clarification zone.

[0014] A method for removing impurities from mother liquor undergoing desalination and crystallization of high-salt chemical waste includes the following steps:

[0015] (1) The mother liquor of chemical high-salt wastewater desalination crystallization is pumped into a high-density sedimentation tank, and the reaction is carried out in a balanced manner to deeply remove impurities such as calcium, magnesium, fluorine, silicon and phosphate.

[0016] (2) Pump the water produced in step (1) into the primary reactor and react under the action of micro electric field A and catalyst A in the primary reactor;

[0017] (3) Pump the product water from step (2) into the secondary reactor and react under the action of micro electric field B and catalyst B in the secondary reactor;

[0018] (4) Pump the product water from step (3) into the three-stage reactor and react under the action of the micro-electric field C and the reducing agent in the three-stage reactor;

[0019] (5) Pump the water produced in step (4) into the filtration device, and then pump the filtered water into the mesoporous adsorption tower for treatment.

[0020] (6) Pump the product water from step (5) into the chelating resin adsorption tower for treatment.

[0021] (7) Pump the product water from step (6) into a modified zeolite adsorption tower for treatment to obtain a pure solution.

[0022] In another specific embodiment of the present invention, in step (1), the residence time of the chemical high-salt wastewater desalination crystallization mother liquor in step (1) is 2-4 hours, and the high-density sedimentation tank includes a high-density sedimentation tank conditioning zone, a high-density sedimentation tank coagulation zone, a high-density sedimentation tank flocculation zone and a high-density sedimentation tank sedimentation zone connected sequentially from left to right. The bottom of the micro-electric field treatment zone of the primary reactor and the sedimentation zone of the primary reactor are connected by a bottom sludge return pipe. A stirring system is provided in the high-density sedimentation tank conditioning zone, the high-density sedimentation tank coagulation zone and the high-density sedimentation tank flocculation zone, and a dosing system is provided on the high-density sedimentation tank conditioning zone. The conditioning and equalization are carried out in the high-density sedimentation tank conditioning zone, and the pH value is adjusted to 9-11 and the TDS is 150000-250000 mg / L. The stirring method of the stirring system is stirring with a mixer or aeration stirring, and the stirring is carried out at normal temperature and pressure.

[0023] In another specific embodiment of the present invention, in step (2), the product water from step (1) is pumped into the primary reactor and the hydraulic retention time is 1-2 hours. The primary reactor includes a primary reactor conditioning zone, a primary reactor micro-electric field treatment zone equipped with a slag scraper, a primary reactor slag storage zone, and a primary reactor sedimentation zone connected from left to right. A stirring device is provided in each of the primary reactor conditioning zone, the primary reactor micro-electric field treatment zone, and the primary reactor slag storage zone. A dosing device is provided in the primary reactor conditioning zone, and the stirring device stirs the mixture at room temperature. The micro-electric field A is arranged in the primary reactor micro-electric field treatment zone. The micro-electric field A is equipped with an immersion electrode plate, which is any one or a combination of several of the following: iron electrode plate, aluminum electrode plate, graphite electrode plate, diamond electrode plate, titanium-iridium-tantalum electrode plate, titanium-nickel-cobalt electrode plate, and titanium-ruthenium-iridium electrode plate. The catalyst A is a functionalized ionic liquid.

[0024] In another specific embodiment of the present invention, in step (3), the permeate from step (2) is pumped into the secondary reactor and the hydraulic retention time is 1-2 hours. The secondary reactor includes a secondary reactor conditioning zone, a secondary reactor micro-electric field treatment zone, and a secondary reactor sedimentation zone connected sequentially from left to right. The bottom of the secondary reactor micro-electric field treatment zone and the secondary reactor sedimentation zone are connected by a bottom sludge return pipe. A stirrer is installed inside the secondary reactor conditioning zone and the secondary reactor micro-electric field treatment zone, and a dosing device is installed on the secondary reactor conditioning zone. The stirrer is used for stirring at normal temperature and pressure. The micro-electric field B is arranged in the secondary reactor micro-electric field treatment zone. The micro-electric field B is equipped with an immersion electrode plate, which is any one or a combination of several of the following: iron electrode plate, aluminum electrode plate, graphite electrode plate, diamond electrode plate, titanium-iridium-tantalum electrode plate, titanium-nickel-cobalt electrode plate, and titanium-ruthenium-iridium electrode plate. The catalyst B is a sulfonic acid-based ionic liquid.

[0025] In a further specific embodiment of the present invention, in step (4), the permeate from step (3) is pumped into the three-stage reactor 4 and the hydraulic retention time is 1-2 hours. The three-stage reactor includes a first adjustment zone, a three-stage reactor micro-electric field treatment zone, a second adjustment zone, a three-stage reactor sedimentation zone, a third adjustment zone, and a clarification zone arranged sequentially from left to right. A stirring system is provided in each of the first adjustment zone, the three-stage reactor micro-electric field treatment zone, the second adjustment zone, and the third adjustment zone. A dosing system is provided in each of the first adjustment zone, the second adjustment zone, and the third adjustment zone. The stirring system stirs at normal temperature and pressure. The micro-electric field C is arranged in the three-stage reactor micro-electric field treatment zone. The micro-electric field C is equipped with an immersion electrode plate, which is any one or a combination of several of the following: iron electrode plate, aluminum electrode plate, graphite electrode plate, diamond electrode plate, titanium-iridium-tantalum electrode plate, titanium-nickel-cobalt electrode plate, and titanium-ruthenium-iridium electrode plate. The reducing agent is an ammonium salt.

[0026] In a more specific embodiment of the present invention, in step (5), the filtration device consists of a quartz sand filter and a precision filter, which are connected in series in a single group, with the quartz sand filter first and the precision filter second, followed by multiple groups connected in parallel after the single group is connected in series; the filtration accuracy of the quartz sand filter is 0.005 to 0.01 mm, and the filtration accuracy of the precision filter is 0.005 to 0.01 μm; the mesoporous adsorption tower is a single group and consists of a support structure, an adsorption tank, a feeding and discharging system, a regeneration system, and a control system. The adsorption tank is filled with mesoporous-microporous adsorbent. The single adsorption tower consists of 3 to 5 adsorption tanks (or adsorption columns) connected in series, with two in use and one on standby, or three in use and one on standby, or four in use and one on standby. Multiple adsorption towers are connected in parallel; the feed flow rate of the mesoporous adsorption tower is 0.5 to 2.5 BV.

[0027] In another specific embodiment of the present invention, in step (6), the chelating resin adsorption tower is composed of a support structure, an adsorption tank (or adsorption column), a feeding and discharging system, a regeneration system and a control system. The adsorption tank is filled with chelating adsorbent. The single chelating resin adsorption tower consists of three adsorption tanks connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The feed flow rate of the chelating resin adsorption tower is 0.5 to 2.5 BV.

[0028] In yet another specific embodiment of the present invention, the modified zeolite adsorption tower in step (7) consists of a support structure, an adsorption tank (or adsorption column), a feeding and discharging system, a regeneration system, and a control system. The adsorption tank is filled with modified zeolite adsorbent. A single modified zeolite adsorption tower consists of three adsorption tanks connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The feed flow rate of the modified zeolite adsorption tower is 0.5 to 2.5 BV.

[0029] The impurity removal device for the mother liquor of high-salt chemical waste water desalination crystallization provided by this invention has a reasonable equipment configuration and good economic efficiency and operability; the method provided has outstanding originality in process route, optimizes the whole process and has low processing cost, and meets the excellent resource utilization requirements of turning waste into treasure. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the impurity removal device for the mother liquor of high-salt chemical waste water desalination crystallization provided by the present invention, and a process flow diagram of the impurity removal method.

[0031] Figure 2 for Figure 1 A schematic diagram of the configuration of the high-density sedimentation tank 1 is shown;

[0032] Figure 3 for Figure 1 The diagram shows the configuration of the primary reactor 2.

[0033] Figure 4 for Figure 1 The diagram shows the configuration of the secondary reactor 3.

[0034] Figure 5 for Figure 1 The diagram shows the configuration of the three-stage reactor 4;

[0035] In the diagram: 1. High-density sedimentation tank; 11. High-density sedimentation tank conditioning zone; 12. High-density sedimentation tank coagulation zone; 13. High-density sedimentation tank flocculation zone; 14. High-density sedimentation tank sedimentation zone; 2. Primary reactor; 21. Primary reactor conditioning zone; 22. Sludge scraper; 22. Primary reactor micro-electric field treatment zone; 23. Primary reactor sludge storage zone; 24. Primary reactor sedimentation zone; 25. Bottom sludge return pipe; 3. Secondary reactor; 31. Secondary reactor conditioning zone; 32. Secondary reactor micro-electric field treatment zone; 33. Secondary reactor sedimentation zone; 34. Bottom sludge return pipe; 4. Tertiary reactor; 41. First-stage conditioning zone; 42. Tertiary reactor micro-electric field treatment zone; 43. Second-stage conditioning zone; 44. Tertiary reactor sedimentation zone; 45. Third-stage conditioning zone; 46. Clarification zone; 5. Filtration device; 6. Mesoporous adsorption tower; 7. Chelating resin tower; 8. Modified zeolite adsorption tower. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below. However, it should be understood that the description herein is for explaining the invention and is not intended to limit the scope of the invention.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0038] Please see Figures 1 to 5 The present invention provides a method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization, comprising the following seven relatively simple and easily operable steps:

[0039] In step (1):

[0040] The above and by Figure 2 The high-density sedimentation tank 1 shown in the diagram consists of a high-density sedimentation tank conditioning zone 11, a high-density sedimentation tank coagulation zone 12, a high-density sedimentation tank flocculation zone 13, and a high-density sedimentation tank sedimentation zone 14. It is equipped with a dosing system, that is, a dosing system is set in the high-density sedimentation tank conditioning zone 11, while a stirring system is set in the high-density sedimentation tank conditioning zone 11, the high-density sedimentation tank coagulation zone 12, and the high-density sedimentation tank flocculation zone 13 to remove impurities such as calcium, magnesium, fluorine, silicon, and phosphate. The hydraulic retention time in the high-density sedimentation tank 1 is 2-4 hours.

[0041] The conditioning and equalization are carried out in the conditioning zone 11 of the high-density sedimentation tank, and the pH is adjusted to 9-11, the TDS is 150000-250000 mg / L, at normal temperature and pressure, and the stirring is carried out by stirring with a mixer or aeration.

[0042] The aforementioned high-density sedimentation tank 1 uses a two-alkali method to remove Mg from the solution. 2+ and Ca 2+ ;OH - With residual Mg in the solution 2+ The reaction produces Mg(OH)₂ precipitate, which in turn contains Mg. 2+ <20mg / L, first add caustic soda to react with magnesium ions (Mg) in the solution. 2+ The reaction, the reaction formula is: Mg 2+ +2OH - =Mg(OH)2↓; then add Na2CO3 to react with calcium ions (Ca) in the solution. 2+ The reaction produces CaCO3 precipitate, which in turn contains Ca... 2+ <30mg / L, the reaction formula is: Na2CO3 + Ca2 + →2Na + +CaCO3↓;

[0043] The dosage of the reagents required to remove calcium, magnesium, fluorine, silicon, phosphate, etc. from the aforementioned solution is calculated based on the content of the target being removed in the mother liquor (i.e., the mother liquor of chemical high-salt wastewater desalination crystallization, hereinafter the same).

[0044] Sodium carbonate solution is used to remove calcium, sodium hydroxide solution is used to remove magnesium, calcium chloride solution is used to remove fluorine, sodium aluminate solution is used to remove silicon, and polyaluminum chloride solution is used to remove phosphate.

[0045] The pH adjustment uses sulfuric acid or hydrochloric acid as the acid and sodium hydroxide solution or caustic soda as the alkali. The water temperature is 20-35℃, the pressure is 101.325kPa (1 standard atmosphere), and the agitator speed is set to 100-300r / min, or the air-to-water ratio of air aeration agitation is 10-20:1.

[0046] The high-density sedimentation tank 1 removes silicon, fluorine, phosphate, etc., so that the silicon content (SiO2) is ≤5mg / l and the fluorine content (F) is ≤5mg / l. - Phosphate (total phosphorus, as P) ≤1 mg / L;

[0047] The high-density sedimentation tank 1 is equipped with a dosing system including a phosphorus removal agent dosing system, a silica removal agent dosing system, a coagulant PAC dosing system, a coagulant aid PAM dosing system, a soda ash dosing system, and a caustic soda dosing system; the surface loading of the high-density sedimentation tank 1 is set to 10-25 m³ / h. 3 / (m 2 •h); The sludge concentration in high-density sedimentation tank 1 is set to 20-50 g / L;

[0048] In step (2):

[0049] The above and by Figure 3 The primary reactor 2 shown includes, from left to right, a primary reactor conditioning zone 21, a primary reactor micro-electric field treatment zone 22 equipped with a scraper 221, a primary reactor sludge storage zone 23, and a primary reactor sedimentation zone 24. The bottom of the primary reactor micro-electric field treatment zone 22 and the primary reactor sedimentation zone 24 are connected by a bottom sludge return pipe 25 (i.e., connected, the same example below). The hydraulic retention time in the primary reactor 2 is 1-2 hours, at normal temperature and pressure.

[0050] The micro-electric field of the primary reactor is micro-electric field A, and it is equipped with an immersion electrode plate. The electrode plate material used in the immersion electrode plate includes one or more of the following: iron electrode plate, aluminum electrode plate, graphite electrode plate, diamond electrode plate, titanium-iridium-tantalum electrode plate, nickel-cobalt electrode plate, and titanium-ruthenium-iridium electrode plate.

[0051] During the operation of the micro-electric field treatment zone 22 of the aforementioned primary reactor, a catalyst is added. This catalyst is defined as catalyst A, and catalyst A is a functionalized ionic liquid.

[0052] The pH of the primary reactor 2 is adjusted to 3-6, the acid used is sulfuric acid or hydrochloric acid, the alkali used is sodium hydroxide solution or caustic soda flakes, the water temperature is 20-35℃, and the pressure is 101.325kPa (1 standard atmosphere). The stirring speed of the agitator set on the adjustment zone 21 of the primary reactor is set to 100-300r / min, or air aeration stirring is used, and the air-to-water ratio of air aeration stirring is 10-20:1.

[0053] Since the micro electric field treatment zone 22 of the first-stage reactor and the sedimentation zone 24 of the first-stage reactor are connected by the bottom sludge return pipe 25, the bottom sludge in the sedimentation zone 24 of the first-stage reactor is returned to the micro electric field treatment zone 22 of the first-stage reactor.

[0054] The function of the aforementioned slag scraper 221 is to scrape the foam generated during the reaction process into the slag storage tank;

[0055] The immersion electrode plate is preferably an iron electrode plate, an aluminum electrode plate, or a titanium-ruthenium-iridium electrode plate, wherein the area of ​​the iron electrode plate accounts for 1% to 3% of the total electrode plate area; and the area of ​​the aluminum electrode plate accounts for 1% to 3% of the total electrode plate area.

[0056] The micro-electric field A uses direct current or alternating current, with an input voltage of 1–2.5V and an input current of 5–30A; the electrode current density is 0.01–0.1 mA / cm². 2 The electrode spacing is 5–25 cm.

[0057] The catalyst A, i.e., the functionalized ionic liquid, is preferably one or two of the following: 1-allyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium acetate, 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-allyl-3-methylimidazolium dinitrile ammonium salt, 1-allyl-3-methylimidazolium p-toluenesulfonate, 1-allyl-3-ethylimidazolium chloride, N-allyl-N-methylpiperidine chloride, and 1-allyl-3-butylimidazolium chloride; the mass ratio of the amount of catalyst A added to the content of inert organic matter is (0.1-0.2):1.

[0058] In step (3):

[0059] The above and by Figure 4 The secondary reactor 3 shown includes a secondary reactor conditioning zone 31, a secondary reactor micro-electric field treatment zone 32, and a secondary reactor sedimentation zone 33 connected sequentially from left to right. The bottom of the secondary reactor micro-electric field treatment zone 32 and the secondary reactor sedimentation zone 33 are connected by a bottom sludge return pipe 34. A dosing device is installed on the secondary reactor conditioning zone 31, and a stirrer is installed in the secondary reactor conditioning zone 31 and the secondary reactor micro-electric field treatment zone 32. The hydraulic retention time in the secondary reactor 3 is 1-2 hours, at normal temperature and pressure.

[0060] The micro-electric field within the micro-electric field treatment zone 32 of the secondary reactor is (i.e., defined as) micro-electric field B, and is equipped with an immersion electrode plate. The electrode plate material used in the immersion electrode plate includes one or more of the following: iron electrode plate, aluminum electrode plate, graphite electrode plate, diamond electrode plate, titanium-iridium-tantalum electrode plate, nickel-cobalt electrode plate, and titanium-ruthenium-iridium electrode plate.

[0061] During the operation of the micro-electric field treatment zone 32 of the aforementioned secondary reactor, a catalyst is added. This catalyst is defined as catalyst B, and catalyst B is a sulfonic acid-based ionic liquid.

[0062] The pH of the secondary reactor 3 is adjusted to 3-6, the acid used is sulfuric acid or hydrochloric acid, the alkali used is sodium hydroxide solution or caustic soda flakes, the water temperature is 20-35℃, the pressure is 101.325kPa (1 standard atmosphere), the agitator speed is set to 100-300r / min, or the air-to-water ratio of air aeration and agitation is 10-20:1.

[0063] The bottom sludge in the sedimentation zone 33 of the secondary reactor is returned to the micro electric field treatment zone 32 of the secondary reactor by the aforementioned bottom sludge return pipe 34.

[0064] The immersion electrode plate is preferably an iron electrode plate, an aluminum electrode plate, or a titanium-iridium-tantalum electrode plate, wherein the area of ​​the iron electrode plate accounts for 1% to 3% of the total electrode plate area; and the area of ​​the aluminum electrode plate accounts for 1% to 3% of the total electrode plate area.

[0065] The micro electric field B uses direct current or alternating current, with an input voltage of 1 to 2.5V, an input current of 5 to 30A, an electrode current density of 0.01 to 0.1 mA / cm², and an electrode spacing of 5 to 25 cm.

[0066] The catalyst B is a sulfonic acid-based ionic liquid, preferably one or two of the following: 1-butylsulfonic acid-3-methylimidazolium p-toluenesulfonate, 1-butylsulfonic acid-3-butylimidazolium chloride, N-butylsulfonic acid pyridine hydrogen sulfate, 1-butylsulfonic acid-3-methylimidazolium trifluoroacetate, 1-propylsulfonic acid-3-vinylimidazolium chloride, 1-propylsulfonic acid-3-methylimidazolium trifluoromethanesulfonate, 1-propylsulfonic acid-3-methylimidazolium chloride, and 1-propylsulfonic acid-3-methylimidazolium dihydrogen phosphate; the mass ratio of the amount of catalyst B added to the content of inert organic matter is (0.1-0.2):1.

[0067] In step (4):

[0068] The above and by Figure 5The three-stage reactor 4 shown includes, from left to right, a first conditioning zone 41, a micro-electric field treatment zone 42, a second conditioning zone 43, a sedimentation zone 44, a third conditioning zone 45, and a clarification zone 46. Each of the first, second, and third conditioning zones 41 and 43 is equipped with a dosing system, and each of these zones is equipped with a stirring system. The hydraulic retention time is 1-2 hours, and the reactor operates at ambient temperature and pressure.

[0069] The micro-electric field within the micro-electric field treatment zone 42 of the three-stage reactor is defined as micro-electric field C. The micro-electric field C is equipped with an immersion electrode plate, and the electrode plate material used in the immersion electrode plate includes one or more of the following: iron electrode plate, aluminum electrode plate, graphite electrode plate, diamond electrode plate, titanium-iridium-tantalum electrode plate, nickel-cobalt electrode plate, and titanium-ruthenium-iridium electrode plate.

[0070] The pH of the first adjustment zone 41 of the three-stage reactor 4 is adjusted to 3-6, the pH of the second adjustment zone 43 is adjusted to 8.5-9, and the pH of the third adjustment zone 45 is adjusted to 6-7. The acid used is sulfuric acid or hydrochloric acid, and the alkali used is sodium hydroxide solution or caustic soda flakes. The water temperature is 20-35℃, and the pressure is 101.325 kPa (1 standard atmosphere). Agitators are installed in the first adjustment zone 41, the second adjustment zone 43, the third adjustment zone 45, and the micro-electric field treatment zone 42 of the three-stage reactor. The agitator speed is set to 100-300 r / min, or the air-to-water ratio of air aeration is 10-20:1.

[0071] The immersion electrode plate is preferably an iron electrode plate, an aluminum electrode plate, or a titanium-nickel-cobalt electrode plate, wherein the area of ​​the iron electrode plate accounts for 1% to 3% of the total electrode plate area; and the area of ​​the aluminum electrode plate accounts for 1% to 3% of the total electrode plate area.

[0072] The micro-electric field C uses direct current or alternating current, with an input voltage of 1–2.5V, an input current of 5–30A, and an electrode current density of 0.01–0.1 mA / cm². 2 The electrode spacing is 5–25 cm;

[0073] The reducing agent is an ammonium salt, preferably one or two of the following: ammonium chloride, ammonium sulfate, ammonium bisulfate, ammonium nitrate, ammonium carbonate, ammonium bicarbonate, ammonium fluoride, ammonium phosphate, ammonium hydroxide, diammonium sulfate, ammonium bromide, and ammonium acetate; the mass ratio of the reducing agent dosage to the nitrate content in the wastewater is (0.5-1):1.

[0074] In step (5):

[0075] Please see Figure 1The filtration device 5 consists of a quartz sand filter and a precision filter, with a single set connected in series, followed by the quartz sand filter and then the precision filter, or multiple sets connected in parallel; the inlet water flow rate is 0.5 to 2.5 BV.

[0076] The filtration accuracy range of the quartz sand filter is 0.005-0.01 mm, and the filtration accuracy range of the precision filter is 0.005-0.01 μm.

[0077] The mesoporous adsorption tower 6 is a single set and consists of a support structure, an adsorption tank (or adsorption column), a feeding and discharging system, a regeneration system, and a control system. The adsorption tank is filled with mesoporous-microporous adsorbent. A single set of adsorption towers consists of 3-5 adsorption tanks (or adsorption columns) connected in series, with two in use and one on standby, three in use and one on standby, or four in use and one on standby. Multiple sets of adsorption towers are connected in parallel.

[0078] The influent flow rate of the mesoporous adsorption tower is 0.5–2.5 BV;

[0079] The quartz sand in the quartz sand filter conforms to the industry standards CJ / T43-2009 and DL / T336-2010, with a density ≥2.55 g / cm³. 3 The hydrochloric acid solubility is ≤3.5%;

[0080] The filter element of the precision filter conforms to ISO 2491 burst resistance test, ISO 2492 structural integrity test, ISO 2493 material and liquid compatibility test, ISO 3723 end load test method, ISO 3724 fatigue characteristics determination, ISO 3968 pressure difference flow characteristics determination, and ISO 4572 multiple pass method for determining filtration characteristics.

[0081] The supporting structure of the mesoporous adsorption tower 6 is made of corrosion-resistant carbon steel.

[0082] The mesoporous adsorption tank (or adsorption column) is made of carbon steel lined with rubber, which is corrosion resistant, and has a diameter-to-height ratio of (2-3):1;

[0083] The mesoporous adsorption tank (or adsorption column) is filled with fixed-bed mesoporous-microporous adsorbent, and the volume ratio of the adsorbent filling amount in a single adsorption tank to the influent volume is 1:1.

[0084] The mesoporous adsorption vessel (or adsorption column) is filled with a mesoporous-microporous composite material with a pore size of 0.1–5 nm and a density of 1.25 g / cm³. 3 Porosity 75-80%, specific surface area 1000-1500 m² 2 / g;

[0085] The regeneration process of the mesoporous adsorption tank (or adsorption column) is as follows: First, prepare a 5% sodium hydroxide solution, the volume ratio of the sodium hydroxide solution to the adsorbent in a single tank is (2-3):1; Second, soak in the 5% sodium hydroxide solution for 30 minutes, the volume ratio of the sodium hydroxide solution to the adsorbent in a single tank is 1:1; Third, pass the remaining sodium hydroxide solution through the column at a flow rate of 2 BV; Fourth, wash with deionized water at a flow rate of 2 BV until neutral.

[0086] The feed flow rate of the mesoporous adsorption tower 6 is 0.5-2.5 BV, the pH is 6-7, the water temperature is 20-35℃, and the pressure is 0.1-0.2 MPa.

[0087] In step (6):

[0088] Depend on Figure 1 The chelating resin adsorption tower 7 shown in the figure consists of a support structure, an adsorption tank (or adsorption column), a feeding and discharging system, a regeneration system, and a control system. The adsorption tank, i.e. the chelating resin adsorption tank (hereinafter the same), is filled with chelating adsorbent. A single adsorption tower consists of 3 adsorption tanks (or adsorption columns) connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel.

[0089] The inlet water flow rate of the chelating resin adsorption tower 7 is 0.5–2.5 BV;

[0090] The supporting structure of the chelating resin adsorption tower 7 is made of corrosion-resistant carbon steel.

[0091] The chelating resin adsorption tank (or adsorption column) is made of carbon steel lined with rubber, which is corrosion resistant, and has a diameter-to-height ratio of (2-3):1;

[0092] The chelating resin adsorption tank is filled with fixed-bed chelating resin adsorbent, and the volume ratio of the adsorbent filling amount in a single adsorption tank to the influent volume is 1:1.

[0093] The ratio of the pore diameter of the chelating resin to the diameter of the adsorbed metal ions is 4 to 8:1, preferably 5:1. The chelating resin is preferably one or a combination of two of the following: phosphonic resin, mercapto resin, thiourea resin, and 4-aminotriazole resin.

[0094] The regeneration process of the chelating resin adsorption tank (or adsorption column) is as follows: First, prepare a 5% hydrochloric acid or sulfuric acid solution, wherein the volume ratio of the hydrochloric acid or sulfuric acid solution to the adsorbent in a single tank is (2-3):1; Second, soak the column in the 5% hydrochloric acid or sulfuric acid solution for 30 minutes, wherein the volume ratio of the hydrochloric acid or sulfuric acid solution to the adsorbent in a single tank is 1:1; Third, pass the remaining hydrochloric acid or sulfuric acid solution through the column at a flow rate of 2 BV; Fourth, wash the column with deionized water at a flow rate of 2 BV until neutral.

[0095] The feed flow rate of the chelating resin adsorption tower 7 is 0.5-2.5 BV, the pH is 6-7, the water temperature is 20-35℃, and the pressure is 0.1-0.2 MPa.

[0096] In step (7):

[0097] Depend on Figure 1 The modified zeolite adsorption tower 8 shown consists of a support structure, an adsorption tank (or adsorption column), a feeding and discharging system, a regeneration system, and a control system. The adsorption tank, also known as the modified zeolite adsorption tank (hereinafter the same), is filled with modified zeolite adsorbent. A single adsorption tower consists of 3 adsorption tanks (or adsorption columns) connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel.

[0098] The inlet flow rate of the modified zeolite adsorption tower 8 is 0.5–2.5 BV;

[0099] The supporting structure of the modified zeolite adsorption tower 8 is made of corrosion-resistant carbon steel.

[0100] The modified zeolite adsorption tank (or adsorption column) is made of carbon steel lined with rubber, which is corrosion resistant, and has a diameter-to-height ratio of (2-3):1.

[0101] The modified zeolite adsorption tank (or adsorption column) is filled with fixed-bed modified zeolite adsorbent, and the volume ratio of the adsorbent filling amount in a single adsorption tank to the influent volume is 1:1.

[0102] The zeolite raw material of the modified zeolite is natural clinoptilolite and / or artificial clinoptilolite.

[0103] The zeolite modification process of the modified zeolite is as follows: natural clinoptilolite and / or artificial clinoptilolite are completely immersed in an inorganic salt saturated solution and boiled. The pH value of the inorganic salt saturated solution is 6-9, the boiling time is 1-2 hours, cooled to room temperature, and boiled again. The boiling is repeated three times under the same conditions. The inorganic salt includes one of sodium chloride, ammonium chloride, barium chloride, and strontium chloride, preferably sodium chloride or barium chloride.

[0104] The regeneration process of the modified zeolite adsorption tank (or adsorption column) is as follows: First, prepare a saturated ammonium sulfate solution with a pH of 7-9. The volume ratio of the saturated ammonium sulfate solution to the adsorbent packed in the single tank is (2-3):1. Second, pass the saturated ammonium sulfate solution through the column at a flow rate of 2 BV. The desorbed liquid after passing through the column is a saturated ammonium sulfate potassium liquid compound fertilizer, which can be further dried into a solid compound fertilizer. Third, wash the column once with an equivalent amount of deionized water at a flow rate of 2 BV.

[0105] The modified zeolite adsorption tower 8 has an inlet water flow rate of 0.5–2.5 BV, a pH of 6–7, a water temperature of 20–35 °C, and a pressure of 0.1–0.2 MPa.

[0106] The advantages of the method of the present invention compared with existing technologies are further summarized as follows:

[0107] 1. It adopts a unique impurity removal technology and continuous liquid-phase processing, which shortens the processing cycle;

[0108] 2. Compared with traditional impurity removal technologies, it can significantly reduce impurity removal costs;

[0109] 3. It adopts a normal temperature and pressure liquid phase treatment process, which has high stability, strong adaptability and strong impact resistance;

[0110] 4. Using ammonium sulfate as a potassium ion desorbent (or desorption agent), and producing ammonium sulfate potassium compound fertilizer as a byproduct, turning waste into treasure and realizing the high-value utilization of potassium ions;

[0111] 5. It highlights both environmental protection attributes and resource attributes, enabling environmental protection projects to shift from a "loss-making → profit-making" model.

[0112] The method of this invention takes into account the characteristics of the mother liquor of high-salt chemical waste water desalination crystallization, and forms a complete liquid phase treatment path to address the bottleneck of impurity removal technology, thereby eliminating the mother liquor and thus eliminating the generation of impurities (hazardous waste).

[0113] To further understand the present invention, the present invention will be further described in detail below with reference to the water quality of the mother liquor from the desalination crystallization of high-salt wastewater in a coal chemical industry, using Examples 1 to 3.

[0114] The impurities listed in the table below account for 3.15%, while sodium sulfate and sodium chloride account for 96.85%.

[0115]

[0116] Example 1

[0117] like Figure 1 As shown, a method for removing impurities from mother liquor undergoing desalination and crystallization of high-salt chemical wastewater is disclosed, the method comprising the following steps:

[0118] (1) The mother liquor is pumped into a high-density sedimentation tank 1 for conditioning and equalization to remove impurities such as calcium, magnesium, fluorine, silicon, and phosphate. The hydraulic retention time is 2 hours. The pH is adjusted to 9 and the TDS is 150,000 mg / L. The dosage of the reagents required for removing calcium, magnesium, fluorine, silicon, and phosphate is calculated based on the content of the target substance in the mother liquor. Sodium carbonate solution is used for calcium removal, sodium hydroxide solution is used for magnesium removal, calcium chloride solution is used for fluorine removal, sodium aluminate solution is used for silicon removal, and polyaluminum chloride solution is used for phosphate removal. Mg in the solution is removed using the two-alkali method. 2+ and Ca 2+ ;OH - With residual Mg in the solution2+ The reaction produces Mg(OH)₂ precipitate, which in turn contains Mg. 2+ <20mg / L, first add caustic soda to react with magnesium ions (Mg) in the solution. 2+ The reaction, the reaction formula is: Mg 2+ +2OH - =Mg(OH)2↓; then add Na2CO3 to react with calcium ions (Ca) in the solution. 2+ The reaction produces CaCO3 precipitate, which in turn contains Ca... 2+ <30mg / L, the reaction formula is: Na2CO3 + Ca2 + →2Na + +CaCO3↓; The acid used to adjust the pH is sulfuric acid, and the alkali used is sodium hydroxide solution. The water temperature is 20℃, and the pressure is 101.325 kPa (1 standard atmosphere). The stirring tank is stirred using a stirrer with a speed set to 100 r / min; to ensure that the silicon content (SiO2) is ≤5 mg / L and the fluorine content (F) is ≤5 mg / L. - ≤1mg / l for total phosphorus (P); High-density sedimentation tank 1 is equipped with a phosphorus removal agent dosing system, a silica removal agent dosing system, a coagulant PAC dosing system, a coagulant aid PAM dosing system, a soda ash dosing system, a caustic soda dosing system, and a mixing system; The surface loading rate of high-density sedimentation tank 1 is set to 10m³ / L. 3 / (m 2 •h); The sludge concentration in high-density sedimentation tank 1 is set to 20g / l;

[0119] (2) The product water from step (1) is pumped into the primary reactor 2 and reacted under the action of micro electric field A and catalyst A; the hydraulic residence time is 1h; the pH of the primary reactor 2 is adjusted to 3, the acid used is sulfuric acid, the alkali used is sodium hydroxide solution, the water temperature is 20℃, the pressure is 101.325kPa (1 standard atmosphere), the micro electric field treatment zone 22 of the primary reactor is aerated and stirred with air, the air-to-water ratio is 10:1, the adjustment zone 21 of the primary reactor is stirred with a stirring device and the speed is set to 100r / min; The bottom sludge in the sedimentation zone 24 of the primary reactor is returned to the micro-electric field treatment zone 22 of the primary reactor through the bottom sludge return pipe 25. A scraper 221, positioned above the liquid surface in the micro-electric field treatment zone 22, scrapes the foam generated during the reaction into the sludge storage tank. The submerged electrode plates are preferably iron, aluminum, or titanium-ruthenium-iridium plates, with the iron plate area accounting for 1% of the total electrode plate area and the aluminum plate area accounting for 1% of the total electrode plate area. The micro-electric field A uses direct current with an input voltage of 1V and an input current of 5A; the electrode current density is 0.01mA / cm². 2The electrode spacing is 5 cm; catalyst A is a functionalized ionic liquid, preferably 1-allyl-3-methylimidazolium chloride and 1-allyl-3-methylimidazolium acetate, with a mass ratio of 1:1; the mass ratio of catalyst A to inert organic matter content is 0.1:1.

[0120] (3) The product water from step (2) is pumped into the secondary reactor 3 and reacted under the action of micro-electric field B and catalyst B; the hydraulic retention time is 1 h; the pH of the secondary reactor 3 is adjusted to 3, the acid used is sulfuric acid, the alkali used is sodium hydroxide solution, the water temperature is 20℃, and the pressure is 101.325 kPa (1 standard atmosphere); the micro-electric field treatment zone 32 of the secondary reactor is aerated and stirred with air, and the air-to-water ratio is 10:1; the stirring in the adjustment zone 31 of the secondary reactor is done with a stirrer, and the speed is set to 100 r / min; the bottom sludge in the sedimentation zone 33 of the secondary reactor is returned to the micro-electric field treatment zone 32 of the secondary reactor through the bottom sludge return pipe 34; the submerged electrode plates are preferably iron electrode plates, aluminum electrode plates, or titanium-iridium-tantalum electrode plates, wherein the area of ​​the iron electrode plate accounts for 1% of the total electrode plate area; the area of ​​the aluminum electrode plate accounts for 1% of the total electrode plate area; the micro-electric field B uses direct current, with an input voltage of 1V and an input current of 5A; the electrode plate current density is 0.01 mA / cm². 2 The electrode spacing is 5 cm; catalyst B is a sulfonic acid-based ionic liquid, preferably 1-butylsulfonic acid-3-methylimidazolium p-toluenesulfonate or 1-butylsulfonic acid-3-butylimidazolium chloride, with a mass ratio of 1:1; the mass ratio of catalyst B to inert organic matter content is 0.1:1.

[0121] (4) The product water from step (3) is pumped into the three-stage reactor 4 and reacted under the action of micro-electric field C and reducing agent; the hydraulic retention time is 1-2 hours; the pH of the first adjustment zone 41 of the three-stage reactor 4 is adjusted to 3, the pH of the second adjustment zone 43 is adjusted to 8.5, and the pH of the third adjustment zone 45 is adjusted to 6. The acid used is sulfuric acid, the alkali used is sodium hydroxide solution, the water temperature is 20℃, and the pressure is 101.325 kPa (1 standard atmosphere). The stirring system of the micro-electric field treatment zone 42 of the three-stage reactor... Air aeration and stirring are employed, with an air-to-water ratio of 10:1. Other adjustment zones, such as the first, second, and third adjustment zones 41, 43, and 45, utilize mechanical stirring systems with a speed set to 100-300 r / min. The submerged electrode plates are preferably iron, aluminum, or titanium-nickel-cobalt electrodes, with the iron electrode plate area accounting for 1% of the total electrode plate area, and the aluminum electrode plate area accounting for 1% of the total electrode plate area. The micro-electric field C uses direct current, with an input voltage of 1V and an input current of 5A; the electrode plate current density is 0.01 mA / cm². 2The electrode spacing is 5 cm; the reducing agent is an ammonium salt, preferably ammonium chloride or ammonium sulfate, with a mass ratio of 1:1; the mass ratio of the reducing agent dosage to the nitrate content in the wastewater is 0.5:1.

[0122] (5) The product water from step (4) is pumped into filter device 5 for filtration. The water filtered by filter device 5 is then pumped into mesoporous adsorption tower 6 for treatment. Filter device 5 consists of a quartz sand filter and a precision filter, connected in series in a single unit with an inlet flow rate of 0.5 BV. The quartz sand filter is followed by the precision filter, with multiple units connected in parallel. The filtration accuracy of the quartz sand filter is 0.005-0.01 mm, and the filtration accuracy of the precision filter is 0.005-0.01 μm. The mesoporous adsorption tower... Each unit consists of a support structure, an adsorption tank (or adsorption column), a feeding and discharging system, a regeneration system, and a control system. The adsorption tank is filled with a certain amount of mesoporous-microporous adsorbent. A single adsorption tower consists of three adsorption tanks (or adsorption columns) connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The inlet water flow rate of the mesoporous adsorption tower 6 is 0.5–2.5 BV. The quartz sand in the quartz stone filter conforms to the industry standards CJ / T43-2009 and DL / T336-2010, with a density ≥2.55 g / cm³. 3 The hydrochloric acid solubility is ≤3.5%; the filter element of the precision filter conforms to ISO 2491 burst resistance test, ISO 2492 structural integrity test, ISO 2493 material and liquid compatibility test, ISO 3723 end load test method, ISO 3724 fatigue characteristics determination, ISO 3968 pressure difference flow characteristics determination, and ISO 4572 multiple pass method for determining filtration characteristics; the supporting structure of the mesoporous adsorption tower 6 is made of corrosion-resistant carbon steel; the mesoporous adsorption tank (or adsorption column) is made of corrosion-resistant carbon steel lined with rubber, with a diameter-to-height ratio of 2:1; the mesoporous adsorption tank (or adsorption column) is filled with fixed-bed mesoporous-microporous adsorbent, and the volume ratio of adsorbent filling amount to influent volume in a single adsorption tank is 1:1; the mesoporous-microporous composite material filled in the mesoporous adsorption tank (or adsorption column) has a pore size of 0.1-5 nm and a density of 1.25 g / cm³. 3 Porosity 75-80%, specific surface area 1000-1500 m² 2 / g; The regeneration process of the mesoporous adsorption tank (or adsorption column) is as follows: First, prepare a 5% sodium hydroxide solution, the volume ratio of the sodium hydroxide solution to the adsorbent in the single tank is 2:1; Second, soak in the 5% sodium hydroxide solution for 30 minutes, the volume ratio of the sodium hydroxide solution to the adsorbent in the single tank is 1:1; Third, pass the remaining sodium hydroxide solution through the column at a flow rate of 2 BV; Fourth, wash with deionized water at a flow rate of 2 BV until neutral; The inlet water flow rate of the mesoporous adsorption tower 6 is 0.5 BV, the pH is 6, the water temperature is 20℃, and the pressure is 0.1 MPa;

[0123] (6) The product water from step (5) is pumped into the chelating resin adsorption tower 7 for treatment; the chelating resin adsorption tower 7 consists of a support structure, an adsorption tank (or adsorption column), an inlet / outlet system, a regeneration system, and a control system. The adsorption tank is filled with a certain amount of chelating adsorbent. A single adsorption tower consists of 3 adsorption tanks (or adsorption columns) connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The inlet flow rate of the chelating resin adsorption tower 7 is 0.5 to 2.5 BV. The support structure of the chelating resin adsorption tower 7 is made of corrosion-resistant carbon steel. The chelating resin adsorption tank (or adsorption column) is made of rubber-lined carbon steel, which is corrosion-resistant, and has a diameter-to-height ratio of 2:1. The chelating resin adsorption tank is filled with fixed-bed chelating resin adsorbent, and the volume ratio of the adsorbent filling amount in a single adsorption tank to the inlet water volume is 1:1. The ratio of the pore diameter of the chelating resin to the diameter of the adsorbed metal ions is 4-8:1, preferably 5:1. The chelating resin is preferably a combination of phosphonic acid resin and mercapto resin, with a volume ratio of 1:1. The regeneration process of the chelating resin adsorption tank (or adsorption column) is as follows: First, prepare a 5% hydrochloric acid solution, with a volume ratio of the hydrochloric acid solution to the adsorbent in the single tank of 2:1. Second, soak in the 5% hydrochloric acid solution for 30 minutes, with a volume ratio of the hydrochloric acid solution to the adsorbent in the single tank of 1:1. Third, pass the remaining hydrochloric acid solution through the column at a flow rate of 2 BV. Fourth, wash with deionized water at a flow rate of 2 BV until neutral. The inlet water flow rate of the chelating resin adsorption tower 7 is 0.5 BV, the pH is 6, the water temperature is 20℃, and the pressure is 0.1 MPa.

[0124] (7) The product water from step (6) is pumped into the modified zeolite adsorption tower 8 for treatment, and the resulting product water is a pure solution. The modified zeolite adsorption tower 8 consists of a support structure, an adsorption tank (or adsorption column), a feed and discharge system, a regeneration system, and a control system. The adsorption tank is filled with a certain amount of modified zeolite adsorbent. Each adsorption tower consists of three adsorption tanks (or adsorption columns) connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The inlet flow rate of the modified zeolite adsorption tower 8 is 0.5 BV. The support structure of the modified zeolite adsorption tower 8 is made of corrosion-resistant carbon steel. The modified zeolite adsorption tank (or adsorption column) is made of rubber-lined carbon steel, corrosion-resistant, with a diameter-to-height ratio of 2:1. The modified zeolite adsorption tank (or adsorption column) is filled with fixed-bed modified zeolite adsorbent, and the volume ratio of adsorbent filling to inlet water in a single adsorption tank is 1:1. The zeolite raw material for the modified zeolite is natural clinoptilolite. The zeolite modification process involves completely immersing natural clinoptilolite in inorganic salts. The modified zeolite adsorption tank (or adsorption column) is boiled in a saturated solution with a pH of 6 for 1 hour. After cooling to room temperature, it is boiled again, and this process is repeated three times under the same conditions. The inorganic salt includes one of sodium chloride, ammonium chloride, barium chloride, and strontium chloride, with sodium chloride being preferred. The regeneration process of the modified zeolite adsorption tank (or adsorption column) is as follows: First, a saturated ammonium sulfate solution with a pH of 7 is prepared, with a volume ratio of the saturated ammonium sulfate solution to the adsorbent in a single tank of 2:1. Second, the saturated ammonium sulfate solution is passed through the column at a flow rate of 2 BV. The desorbed liquid from the column is saturated potassium ammonium sulfate liquid compound fertilizer, which can be further dried into solid compound fertilizer. Third, the column is washed once with an equivalent amount of deionized water at a flow rate of 2 BV. The inlet water flow rate of the modified zeolite adsorption tower is 0.5 BV, the pH is 6, the water temperature is 20℃, and the pressure is 0.1 MPa.

[0125] Example 2

[0126] like Figure 1 As shown, a method for removing impurities from mother liquor undergoing desalination and crystallization of high-salt chemical wastewater is disclosed, the method comprising the following steps:

[0127] (1) The mother liquor is pumped into high-density sedimentation tank 1 for conditioning and equalization to remove impurities such as calcium, magnesium, fluorine, silicon, and phosphate. The hydraulic retention time is 3 hours. The feed is adjusted to pH 10 and TDS 200,000 mg / L. The high-density sedimentation tank 1 uses a two-alkali method to remove Mg from the solution. 2+ and Ca 2+ ;OH - With residual Mg in the solution 2+ The reaction produces Mg(OH)₂ precipitate, which in turn contains Mg. 2+ <20mg / L, first add caustic soda to react with magnesium ions (Mg) in the solution. 2+ The reaction, the reaction formula is: Mg2+ +2OH - =Mg(OH)2↓; then add Na2CO3 to react with calcium ions (Ca) in the solution. 2+ The reaction produces CaCO3 precipitate, which in turn contains Ca... 2+ <30mg / L, the reaction formula is: Na2CO3 + Ca2 + →2Na + +CaCO3↓; The dosage of the reagents required for removing calcium, magnesium, fluorine, silicon, phosphate, etc., is calculated based on the content of the target substance in the mother liquor; sodium carbonate solution is used for calcium removal, sodium hydroxide solution for magnesium removal, calcium chloride solution for fluorine removal, sodium aluminate solution for silicon removal, and polyaluminum chloride solution for phosphate removal; the acid used for pH adjustment is hydrochloric acid, the alkali used is sodium hydroxide solution, the water temperature is 27.5℃, the pressure is 101.325kPa (1 standard atmosphere), and air aeration and stirring are used, with an air-to-water ratio of 15:1; the high-density tank removes silicon, fluorine, phosphate, etc., so that the silicon content (SiO2) ≤ 5mg / l and the fluorine content (F... - Phosphate (total phosphorus, calculated as P) ≤ 1 mg / L; the high-density sedimentation tank 1 is equipped with a phosphorus removal agent dosing system, a silica removal agent dosing system, a coagulant PAC dosing system, a coagulant aid PAM dosing system, a soda ash dosing system, a caustic soda dosing system, and a mixing system; the surface loading rate of the high-density sedimentation tank 1 is set to 17.5 m³ / L. 3 / (m 2 •h); The sludge concentration in high-density sedimentation tank 1 is set to 35g / l;

[0128] (2) The product water from step (1) is pumped into primary reactor 2 and reacted under the action of micro-electric field A and catalyst A. The primary reactor 2 consists of a primary reactor conditioning zone 21, a primary reactor micro-electric field treatment zone 22 (equipped with a slag scraper 221), a primary reactor slag storage zone 23, and a primary reactor sedimentation zone 24, with a hydraulic retention time of 1.5 h. The micro-electric field A is placed in the primary reactor micro-electric field treatment zone 22 and equipped with submerged electrode plates. The catalyst A is a functionalized ionic liquid. The pH of the primary reactor 2 is adjusted to 4.5, the acid used is hydrochloric acid, the alkali used is sodium hydroxide solution, the water temperature is 27.5℃, and the pressure is 101.325 kPa (1 standard atmosphere). The reaction process is carried out under pressure using air aeration and stirring, with an air-to-water ratio of 15:1. The bottom sludge in the sedimentation zone 24 of the primary reactor is returned to the micro-electric field treatment zone 22 of the primary reactor via the bottom sludge return pipe 25. A scraper 221 positioned above the liquid surface in the micro-electric field treatment zone 22 scrapes the foam generated during the reaction into the sludge storage tank, i.e., the sludge storage zone 23 of the primary reactor. The submerged electrode plates are preferably iron, aluminum, or titanium-ruthenium-iridium electrodes, with the iron electrode plate area accounting for 2% of the total electrode plate area and the aluminum electrode plate area accounting for 2% of the total electrode plate area. The micro-electric field A uses direct current, with an input voltage of 1.75V and an input current of 17.5A; the electrode current density is 0.05mA / cm². 2 The electrode spacing is 15 cm. The catalyst A is a functionalized ionic liquid, preferably 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt or 1-allyl-3-methylimidazolium dinitrile ammonium salt, with a mass ratio of 1:1; the mass ratio of the amount of catalyst A added to the content of inert organic matter is 0.15:1.

[0129] (3) The permeate from step (2) is pumped into secondary reactor 3 and reacted under the action of micro-electric field B and catalyst B. Secondary reactor 3 consists of a secondary reactor conditioning zone 31, a secondary reactor micro-electric field treatment zone 32, and a secondary reactor sedimentation zone 33. It is equipped with a dosing system and a stirrer, and the hydraulic retention time is 1.5 h. Micro-electric field B is placed in the reaction zone. Catalyst B is a sulfonic acid-based ionic liquid. The pH of the feed to secondary reactor 3 is adjusted to 4.5, the acid used is hydrochloric acid, the alkali used is sodium hydroxide solution, the water temperature is 27.5℃, and the pressure is... The system operates at 101.325 kPa (1 standard atmosphere), using air aeration and stirring with an air-to-water ratio of 15:1. The bottom sediment from the sedimentation zone 33 of the secondary reactor is returned to the micro-electric field treatment zone 32 of the secondary reactor via a bottom sediment return pipe 34. The submerged electrode plates are preferably iron, aluminum, or titanium-iridium-tantalum electrodes, with the iron electrode area accounting for 2% of the total electrode plate area and the aluminum electrode area accounting for 2% of the total electrode plate area. The micro-electric field B uses alternating current with an input voltage of 1.75V and an input current of 17.5A; the electrode current density is 0.05 mA / cm².2 The electrode spacing is 15 cm; the catalyst B is a sulfonic acid-based ionic liquid, preferably N-butylsulfonic acid pyridine hydrogen sulfate or 1-butylsulfonic acid-3-methylimidazolium trifluoroacetate, with a mass ratio of 1:1; the mass ratio of the amount of catalyst B added to the content of inert organic matter is 0.15:1.

[0130] (4) The permeate from step (3) is pumped into the three-stage reactor 4 and reacted under the action of a micro-electric field C and a reducing agent. The three-stage reactor 4 consists of a first-stage conditioning zone 41, a three-stage reactor micro-electric field treatment zone 42, a second-stage conditioning zone 43, a three-stage reactor sedimentation zone 44, a third-stage conditioning zone 45, and a clarification zone 46. A dosing system and a stirring system are configured, and the hydraulic retention time is 1.5 h. The micro-electric field C is placed in the reaction zone and equipped with submerged electrode plates. The reducing agent is an ammonium salt. The pH of the first-stage conditioning zone of the three-stage reactor is adjusted to 4.5, and the pH of the second-stage conditioning zone is adjusted to... The pH in the third adjustment zone is 6.5, using hydrochloric acid as the acid and sodium hydroxide solution as the alkali. The water temperature is 27.5℃, and the pressure is 101.325 kPa (1 standard atmosphere). Air aeration and stirring are used, with an air-to-water ratio of 15:1. The submerged electrode plates are preferably iron, aluminum, or titanium-nickel-cobalt plates, with the iron plate area accounting for 2% of the total electrode plate area and the aluminum plate area accounting for 2% of the total electrode plate area. The micro-electric field C uses alternating current with an input voltage of 1.75V and an input current of 15A. The electrode current density is 0.05 mA / cm². 2 The electrode spacing is 15cm; the reducing agent is an ammonium salt, preferably ammonium bisulfate or ammonium bicarbonate, with a mass ratio of 1:1; the mass ratio of the amount of reducing agent added to the nitrate content in the wastewater is 0.75:1.

[0131] (5) The product water from step (4) is pumped into the filter device 5 for filtration. The water filtered by the filter device 5 is then pumped into the mesoporous adsorption tower 6 for further treatment. The filter device 5 consists of a quartz sand filter and a precision filter, connected in series in single sets, with the quartz sand filter first and the precision filter second, or multiple sets connected in parallel. The filtration accuracy of the quartz sand filter is 0.005-0.01 mm, and the filtration accuracy of the precision filter is 0.005-0.01 μm. The mesoporous adsorption tower 6 is supported by a single unit. The system comprises an adsorption tank (or adsorption column), a feeding and discharging system, a regeneration system, and a control system. The adsorption tank is filled with a certain amount of mesoporous-microporous adsorbent. A single adsorption tower consists of four adsorption tanks (or adsorption columns) connected in series, with three in use and one on standby. Multiple adsorption towers are connected in parallel. The inlet water flow rate of the mesoporous adsorption tower 6 is 1.5 BV. The quartz sand in the quartz stone filter conforms to the industry standards CJ / T43-2009 and DL / T336-2010, with a density ≥2.55 g / cm³. 3The hydrochloric acid solubility is ≤3.5%; the filter element of the precision filter conforms to ISO 2491 burst resistance test, ISO 2492 structural integrity test, ISO 2493 material and liquid compatibility test, ISO 3723 end load test method, ISO 3724 fatigue characteristics determination, ISO 3968 pressure difference flow characteristics determination, and ISO 4572 multiple pass method for determining filtration characteristics; the supporting structure of the mesoporous adsorption tower 6 is made of corrosion-resistant carbon steel; the mesoporous adsorption tank (or adsorption column) is made of corrosion-resistant carbon steel lined with rubber, with a diameter-to-height ratio of 2.5:1; the mesoporous adsorption tank (or adsorption column) is filled with fixed-bed mesoporous-microporous adsorbent, and the volume ratio of adsorbent filling amount to influent volume in a single adsorption tank is 1:1; the mesoporous-microporous composite material filled in the mesoporous adsorption tank (or adsorption column) has a pore size of 0.1-5 nm and a density of 1.25 g / cm³. 3 Porosity 75-80%, specific surface area 1000-1500 m² 2 / g; The regeneration process of the mesoporous adsorption tank (or adsorption column) is as follows: First, prepare a 5% sodium hydroxide solution, the volume ratio of the sodium hydroxide solution to the adsorbent in a single tank is 2.5:1; Second, soak in the 5% sodium hydroxide solution for 30 minutes, the volume ratio of the sodium hydroxide solution to the adsorbent in a single tank is 1:1; Third, pass the remaining sodium hydroxide solution through the column at a flow rate of 2 BV; Fourth, wash with deionized water at a flow rate of 2 BV until neutral; The feed flow rate of the mesoporous adsorption tower 6 is 1.5 BV, the pH is 6.5, the water temperature is 27.5℃, and the pressure is 0.15 MPa;

[0132] (6) The permeate from step (5) is pumped into the chelating resin adsorption tower 7 for treatment; the chelating resin adsorption tower 7 consists of a support structure, an adsorption tank (or adsorption column), an inlet / outlet system, a regeneration system, and a control system. The adsorption tank is filled with a certain amount of chelating adsorbent. A single adsorption tower consists of three adsorption tanks (or adsorption columns) connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The feed flow rate of the chelating resin adsorption tower is 0.5 to 2.5 BV. The support structure of the chelating resin adsorption tower 7 is made of corrosion-resistant carbon steel. The chelating resin adsorption tank (or adsorption column) is made of rubber-lined carbon steel, which is corrosion-resistant, and has a diameter-to-height ratio of 2.5:1. The chelating resin adsorption tank is filled with fixed-bed chelating resin adsorbent, and the volume ratio of the adsorbent filling amount in a single adsorption tank to the inlet water volume is 1:1. The ratio of the pore diameter of the chelating resin to the diameter of the adsorbed metal ions is 4-8:1, preferably 5:1. The chelating resin is preferably a combination of mercapto resin and thiourea resin, with a volume ratio of 1:1. The regeneration process of the chelating resin adsorption tank (or adsorption column) is as follows: First, prepare a 5% sulfuric acid solution, with a volume ratio of the sulfuric acid solution to the adsorbent in the single tank of 2.5:1. Second, soak in the 5% sulfuric acid solution for 30 minutes, with a volume ratio of the sulfuric acid solution to the adsorbent in the single tank of 1:1. Third, pass the remaining sulfuric acid solution through the column at a flow rate of 2 BV. Fourth, wash with deionized water at a flow rate of 2 BV until neutral. The inlet water flow rate of the chelating resin adsorption tower 7 is 1.5 BV, the pH is 6.5, the water temperature is 27.5℃, and the pressure is 0.15 MPa.

[0133] (7) The product water from step (6) is pumped into the modified zeolite adsorption tower 8 for treatment, and the resulting product water is a pure solution. The modified zeolite adsorption tower 8 consists of a support structure, adsorption tanks (or adsorption columns), a feed and discharge system, a regeneration system, and a control system. Each adsorption tower group comprises three adsorption tanks (or adsorption columns) connected in series, with two in operation and one as a backup. Multiple adsorption tower groups are connected in parallel. The inlet water flow rate of the modified zeolite adsorption tower 8 is 1.5 BV. The support structure of the modified zeolite adsorption tower 8 is made of corrosion-resistant carbon steel. The modified zeolite adsorption tanks (or adsorption columns) are made of corrosion-resistant carbon steel lined with rubber, with a diameter-to-height ratio of 2.5:1. The modified zeolite adsorption tanks (or adsorption columns) are filled with fixed-bed modified zeolite adsorbent, with a volume ratio of adsorbent to inlet water of 1:1 in a single adsorption tank. The zeolite raw material for the modified zeolite is artificial clinoptilolite. The zeolite modification process involves completely immersing the artificial clinoptilolite in a saturated inorganic salt solution and boiling it. The solution has a pH of 7.5, a boiling time of 1.5 hours, is cooled to room temperature, and then boiled again. This boiling process is repeated three times under the same conditions. The inorganic salt includes one of sodium chloride, ammonium chloride, barium chloride, and strontium chloride, preferably barium chloride. The regeneration process of the modified zeolite adsorption tank (or adsorption column) is as follows: First, prepare a saturated ammonium sulfate solution with a pH of 8. The volume ratio of the saturated ammonium sulfate solution to the adsorbent in a single tank is 2.5:1. Second, pass the saturated ammonium sulfate solution through the column at a flow rate of 2 BV. The desorbed liquid from the column is saturated potassium ammonium sulfate liquid compound fertilizer, which can be further dried into solid compound fertilizer. Third, wash once with an equivalent amount of deionized water at a flow rate of 2 BV. The feed flow rate of the modified zeolite adsorption tower is 1.5 BV, the pH is 6.5, the water temperature is 27.5℃, and the pressure is 0.15 MPa. Example 3

[0134] like Figure 1 As shown, a method for removing impurities from mother liquor undergoing desalination and crystallization of high-salt chemical wastewater is disclosed, the method comprising the following steps:

[0135] (1) The mother liquor is pumped into a high-density sedimentation tank 1 for conditioning and equalization to remove impurities such as calcium, magnesium, fluorine, silicon, and phosphate. The high-density sedimentation tank 1 consists of a conditioning zone 11, a coagulation zone 12, a flocculation zone 13, and a sedimentation zone 14. A dosing system and a stirring system are prepared to remove impurities such as calcium, magnesium, fluorine, silicon, and phosphate. The hydraulic retention time is 4 hours. Conditioning and equalization are carried out in the conditioning zone, and the feed is adjusted to pH 11 and TDS 250,000 mg / L. The high-density sedimentation tank 1 uses a two-alkali method to remove Mg from the solution. 2+ and Ca 2+ ;OH - With residual Mg in the solution 2+The reaction produces Mg(OH)₂ precipitate, which in turn contains Mg. 2+ <20mg / L, first add caustic soda to react with magnesium ions (Mg) in the solution. 2+ The reaction, the reaction formula is: Mg 2+ +2OH - =Mg(OH)2↓; then add Na2CO3 to react with calcium ions (Ca) in the solution. 2+ The reaction produces CaCO3 precipitate, which in turn contains Ca... 2+ <30mg / L, the reaction formula is: Na2CO3 + Ca2 + →2Na + +CaCO3↓; The dosage of the reagents required for removing calcium, magnesium, fluorine, silicon, phosphate, etc., is calculated based on the content of the target substance in the mother liquor; sodium carbonate solution is used for calcium removal, sodium hydroxide solution for magnesium removal, calcium chloride solution for fluorine removal, sodium aluminate solution for silicon removal, and polyaluminum chloride solution for phosphate removal; the pH adjustment uses hydrochloric acid as the acid and sodium hydroxide solution as the alkali, the water temperature is 35℃, the pressure is 101.325kPa (1 standard atmosphere), and air aeration and stirring are used, with an air-to-water ratio of 20:1; the high-density tank removes silicon, fluorine, phosphate, etc., so that the silicon content (SiO2) ≤ 5mg / l and the fluorine content (F... - Phosphate (total phosphorus, as P) ≤ 1 mg / L; the high-density sedimentation tank 1 is equipped with a phosphorus removal agent dosing system, a silica removal agent dosing system, a coagulant PAC dosing system, a coagulant aid PAM dosing system, a soda ash dosing system, a caustic soda dosing system, and a mixing system; the surface loading rate of the high-density sedimentation tank 1 is set to 25 m³ / L. 3 / (m 2 •h); The sludge concentration in the high-density tank is set to 50g / l;

[0136] (2) The product water from step (1) is pumped into primary reactor 2 and reacted under the action of micro-electric field A and catalyst A; the primary reactor 2 consists of a primary reactor conditioning zone 21, a primary reactor micro-electric field treatment zone 22 (equipped with a scraper 221), a primary reactor slag storage zone 23, and a primary reactor sedimentation zone 24, with a hydraulic retention time of 2 hours; the micro-electric field A is placed in the reaction zone and equipped with submerged electrode plates; the catalyst A is a functionalized ionic liquid; the pH of the primary reactor 2 is adjusted to 6, the acid used is hydrochloric acid, the alkali used is sodium hydroxide solution, the water temperature is 35°C, and the pressure is 101.325 kPa (1 standard large). The reaction process employs air aeration and stirring, with an air-to-water ratio of 20:1. The bottom sludge in the sedimentation zone 24 of the primary reactor is returned to the micro-electric field treatment zone 22 of the primary reactor via the bottom sludge return pipe 25. A scraper 221 positioned above the liquid surface in the micro-electric field treatment zone 22 scrapes the foam generated during the reaction into a sludge storage tank. The submerged electrode plates are preferably iron, aluminum, or titanium-ruthenium-iridium electrodes, with the iron electrode area accounting for 3% of the total electrode plate area and the aluminum electrode area accounting for 3% of the total electrode plate area. The micro-electric field A uses direct current with an input voltage of 2.5V and an input current of 30A; the electrode current density is 0.1 mA / cm². 2 The electrode spacing is 25 cm; the catalyst A is a functionalized ionic liquid, preferably 1-allyl-3-methylimidazolium p-toluenesulfonate and N-allyl-N-methylpiperidine chloride, with a mass ratio of 1:1; the mass ratio of the amount of catalyst A added to the content of inert organic matter is 0.2:1.

[0137] (3) The permeate from step (2) is pumped into the secondary reactor 3 and reacted under the action of micro-electric field B and catalyst B. The secondary reactor 3 consists of a secondary reactor conditioning zone 31, a secondary reactor micro-electric field treatment zone 32, and a secondary reactor sedimentation zone 33. A dosing system and a stirrer are provided, and the hydraulic retention time is 2 hours. The micro-electric field B is placed in the reaction zone and is equipped with submerged electrode plates. The catalyst B is a sulfonic acid-based ionic liquid. The pH of the secondary reactor is adjusted to 6, the acid used is hydrochloric acid, the alkali used is sodium hydroxide solution, the water temperature is 35°C, and the pressure is... The pressure is 101.325 kPa (1 standard atmosphere), and air aeration and stirring are used, with an air-to-water ratio of 10-20:1. The bottom sludge in the sedimentation zone 23 of the secondary reactor is returned to the micro-electric field treatment zone 32 of the secondary reactor via the bottom sludge return pipe 34. The submerged electrode plates are preferably iron, aluminum, or titanium-iridium-tantalum electrodes, wherein the area of ​​the iron electrode plate accounts for 3% of the total electrode plate area, and the area of ​​the aluminum electrode plate accounts for 3% of the total electrode plate area. The micro-electric field B uses direct current with an input voltage of 2.5V and an input current of 30A; the electrode current density is 0.1 mA / cm². 2The electrode spacing is 25 cm; the catalyst B is a sulfonic acid-based ionic liquid, preferably 1-propylsulfonic acid-3-vinylimidazolium chloride or 1-propylsulfonic acid-3-methylimidazolium trifluoromethane sulfonate, with a mass ratio of 1:1; the mass ratio of the amount of catalyst B added to the content of inert organic matter is 0.2:1.

[0138] (4) The permeate from step (3) is pumped into the tertiary reactor 4 and reacted under the action of the micro-electric field C and the reducing agent. The tertiary reactor 4 consists of a first-stage conditioning zone 41, a tertiary reactor micro-electric field treatment zone 42, a second-stage conditioning zone 43, a tertiary reactor sedimentation zone 44, a third-stage conditioning zone 45, and a clarification zone 46. It is equipped with a dosing system and a stirring system, and the hydraulic retention time is 2 hours. The micro-electric field C is placed in the reaction zone and equipped with submerged electrode plates. The reducing agent is an ammonium salt. The pH of the first-stage conditioning zone 41 of the tertiary reactor 4 is adjusted to 6, and the pH of the second-stage conditioning zone 43 is adjusted to 6. The pH is 9, and the pH in the third adjustment zone (45°C) is 7. Hydrochloric acid is used as the acid, and sodium hydroxide solution is used as the alkali. The water temperature is 35°C, and the pressure is 101.325 kPa (1 standard atmosphere). Air aeration and stirring are used, with an air-to-water ratio of 20:1. The submerged electrode plates are preferably iron, aluminum, or titanium-nickel-cobalt plates, with the iron plate area accounting for 3% of the total electrode plate area and the aluminum plate area accounting for 3%. The micro-electric field C uses direct current, with an input voltage of 2.5V and an input current of 30A. The electrode current density is 0.1 mA / cm². 2 The electrode spacing is 25cm; the reducing agent is an ammonium salt, preferably ammonium hydroxide or ammonium acetate, with a mass ratio of 1:1; the mass ratio of the reducing agent dosage to the nitrate content in the wastewater is 1:1.

[0139] (5) The product water from step (4) is pumped into the filtration device 5. The water filtered by the filtration device 5 is then pumped into the mesoporous adsorption tower 6 for treatment. The filtration device 5 consists of a quartz sand filter and a precision filter, connected in series in a single unit, with a feed flow rate of 2.5 BV. The quartz sand filter is followed by the precision filter, with multiple units connected in parallel. The filtration accuracy of the quartz sand filter is 0.005-0.01 mm, and the filtration accuracy of the precision filter is 0.005-0.01 μm. The mesoporous adsorption tower 6... Each adsorption tower unit consists of a support structure, adsorption tanks (or adsorption columns), a feed and discharge system, a regeneration system, and a control system. The adsorption tanks are filled with a certain amount of mesoporous-microporous adsorbent. A single adsorption tower unit comprises five adsorption tanks (or adsorption columns) connected in series, with four in operation and one on standby. Multiple adsorption tower units are connected in parallel. The influent flow rate of the mesoporous adsorption tower 6 is 2.5 BV. The quartz sand in the quartz sand filter conforms to the industry standards CJ / T43-2009 and DL / T336-2010, with a density ≥2.55 g / cm³. 3The hydrochloric acid solubility is ≤3.5%; the filter element of the precision filter conforms to ISO 2491 burst resistance test, ISO 2492 structural integrity test, ISO 2493 material and liquid compatibility test, ISO 3723 end load test method, ISO 3724 fatigue characteristics determination, ISO 3968 pressure difference flow characteristics determination, and ISO 4572 multiple pass method for determining filtration characteristics; the supporting structure of the mesoporous adsorption tower 6 is made of corrosion-resistant carbon steel; the mesoporous adsorption tank (or adsorption column) is made of carbon steel lined with rubber, corrosion-resistant, with a diameter-to-height ratio of 3:1; the mesoporous adsorption tank (or adsorption column) is filled with fixed-bed mesoporous-microporous adsorbent, and the volume ratio of adsorbent filling amount to influent volume in a single adsorption tank is 1:1; the mesoporous adsorption tank (or adsorption column) is filled with a mesoporous-microporous composite material with a pore size of 0.1-5 nm and a density of 1.25 g / cm³. 3 Porosity 75-80%, specific surface area 1000-1500 m² 2 / g; The regeneration process of the mesoporous adsorption tank (or adsorption column) is as follows: First, prepare a 5% sodium hydroxide solution, the volume ratio of the sodium hydroxide solution to the adsorbent in the single tank is 3:1; Second, soak in the 5% sodium hydroxide solution for 30 minutes, the volume ratio of the 5% sodium hydroxide solution to the adsorbent in the single tank is 1:1; Third, pass the remaining sodium hydroxide solution through the column at a flow rate of 2 BV; Fourth, wash with deionized water at a flow rate of 2 BV until neutral; The feed flow rate of the mesoporous adsorption tower 6 is 2.5 BV, the pH is 7, the water temperature is 35℃, and the pressure is 0.2 MPa;

[0140] (6) The permeate from step (5) is pumped into the chelating resin adsorption tower 7 for treatment; the chelating resin adsorption tower 7 consists of a support structure, an adsorption tank (or adsorption column), an inlet / outlet system, a regeneration system, and a control system. The adsorption tank is filled with a certain amount of chelating adsorbent. A single adsorption tower consists of three adsorption tanks (or adsorption columns) connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The inlet flow rate of the chelating resin adsorption tower 7 is 2.5 BV. The support structure of the chelating resin adsorption tower 7 is made of corrosion-resistant carbon steel. The chelating resin adsorption tank (or adsorption column) is made of rubber-lined carbon steel, which is corrosion-resistant, and has a diameter-to-height ratio of 3:1. The chelating resin adsorption tank is filled with fixed-bed chelating resin adsorbent, and the volume ratio of the adsorbent filling amount in a single adsorption tank to the inlet water volume is 1:1. The ratio of the pore diameter of the resin to the diameter of the adsorbed metal ions is 4-8:1, preferably 5:1. The chelating resin is preferably a combination of two of the following: phosphonic acid resin and 4-aminotriazole resin, with a volume ratio of 1:1. The regeneration process of the chelating resin adsorption tank (or adsorption column) is as follows: First, prepare a 5% hydrochloric acid solution, with a volume ratio of the hydrochloric acid solution to the adsorbent in the single tank being 3:1. Second, soak the adsorbent in the 5% hydrochloric acid solution for 30 minutes, with a volume ratio of the hydrochloric acid solution to the adsorbent in the single tank being 1:1. Third, pass the remaining hydrochloric acid solution through the column at a flow rate of 2 BV. Fourth, wash with deionized water at a flow rate of 2 BV until neutral. The inlet water flow rate of the chelating resin adsorption tower 7 is 2.5 BV, the pH is 7, the water temperature is 35℃, and the pressure is 0.2 MPa.

[0141] (7) The product water from step (6) is pumped into the modified zeolite adsorption tower 8 for treatment, and the resulting product water is a pure solution. Each modified zeolite adsorption tower 8 consists of a support structure, an adsorption tank (or adsorption column), an inlet / outlet system, a regeneration system, and a control system. The adsorption tank is filled with a certain amount of modified zeolite adsorbent. Each adsorption tower consists of three adsorption tanks (or adsorption columns) connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The inlet flow rate of the modified zeolite adsorption tower 8 is 2.5 BV. The support structure of the modified zeolite adsorption tower 8 is made of corrosion-resistant carbon steel. The modified zeolite adsorption tank (or adsorption column) is made of rubber-lined carbon steel, which is corrosion-resistant, and has a diameter-to-height ratio of 3:1. The modified zeolite adsorption tank (or adsorption column) contains… The fixed-bed modified zeolite adsorbent is filled, with the volume ratio of adsorbent filling amount to influent volume in a single adsorption tank being 1:1. The zeolite raw materials for the modified zeolite are natural clinoptilolite and artificial clinoptilolite, with a volume ratio of 1:1. The zeolite modification process of the modified zeolite is as follows: the natural clinoptilolite and artificial clinoptilolite are completely immersed in an inorganic salt saturated solution and boiled. The pH value of the inorganic salt saturated solution is 9, the boiling time is 2 hours, cooled to room temperature, and boiled again. The boiling is repeated three times under the same conditions. The inorganic salt includes one of sodium chloride, ammonium chloride, barium chloride, and strontium chloride, preferably sodium chloride. The regeneration process of the modified zeolite adsorption tank (or adsorption column) is as follows: First, prepare a saturated ammonium sulfate solution with a pH of 9. The volume ratio of the saturated ammonium sulfate solution to the adsorbent packed in the single tank is 3:1. Second, pass the saturated ammonium sulfate solution through the column at a flow rate of 2 BV. The desorbed liquid from the column is saturated potassium ammonium sulfate liquid compound fertilizer, which can be further dried into solid compound fertilizer. Third, wash the column once with an equivalent amount of deionized water at a flow rate of 2 BV. The inlet water flow rate of the modified zeolite adsorption tower is 2.5 BV, the pH is 7, the water temperature is 35℃, and the pressure is 0.2 MPa.

[0142] The technical indicators of the treated high-salt wastewater desalination crystallization mother liquor from the above-described Examples 1 to 3, as shown in the table below, are as follows:

[0143]

[0144] The above description is merely a specific embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A device for removing impurities from mother liquor undergoing desalination and crystallization of high-salt chemical wastewater, characterized in that: The system includes a high-density sedimentation tank (1) for receiving mother liquor from high-salt wastewater; a primary reactor (2) connected to the high-density sedimentation tank (1) via a pipeline; a secondary reactor (3) connected to the primary reactor (2) via a pipeline; and a tertiary reactor (4) connected to a filter device (5) via a pipeline, which in turn is connected to a mesoporous adsorption tower (6) via a pipeline, which is connected to a chelating resin tower (7) via a pipeline, which is connected to a modified zeolite adsorption tower (8) via a pipeline.

2. The impurity removal device for the mother liquor of high-salt chemical wastewater desalination crystallization according to claim 1, characterized in that: The high-density sedimentation tank (1) comprises, from left to right, a high-density sedimentation tank conditioning zone (11), a high-density sedimentation tank coagulation zone (12), a high-density sedimentation tank flocculation zone (13), and a high-density sedimentation tank sedimentation zone (14); the primary reactor (2) comprises, from left to right, a primary reactor conditioning zone (21), a primary reactor micro-electric field treatment zone (22) equipped with a scraper (221), a primary reactor sludge storage zone (23), and a primary reactor sedimentation zone (24), and the bottom of the primary reactor micro-electric field treatment zone (22) and the primary reactor sedimentation zone (24) are connected by a bottom sludge return pipe (…). 25) Connected; The secondary reactor (3) includes a secondary reactor conditioning zone (31), a secondary reactor micro-electric field treatment zone (32) and a secondary reactor sedimentation zone (33) connected from left to right, and the bottom of the secondary reactor micro-electric field treatment zone (32) and the secondary reactor sedimentation zone (33) are connected by a bottom sludge return pipe (34); The tertiary reactor (4) includes a first conditioning zone (41), a tertiary reactor micro-electric field treatment zone (42), a second conditioning zone (43), a tertiary reactor sedimentation zone (44), a third conditioning zone (45) and a clarification zone (46) arranged from left to right.

3. A method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization as described in claim 1, characterized in that, The following steps are involved: (1) Pump the mother liquor of chemical high-salt wastewater desalination crystallization into a high-density sedimentation tank (1) to adjust the quality and balance the reaction, and deeply remove impurities such as calcium, magnesium, fluorine, silicon and phosphate. (2) Pump the water produced in step (1) into the primary reactor (2) and react under the action of micro electric field A and catalyst A in the primary reactor (2); (3) Pump the product water from step (2) into the secondary reactor (3) and react under the action of the micro electric field B and catalyst B in the secondary reactor (3); (4) Pump the product water from step (3) into the three-stage reactor (4) and react under the action of the micro-electric field C and the reducing agent in the three-stage reactor (4); (5) Pump the water produced in step (4) into the filtration device, and pump the filtered water into the mesoporous adsorption tower (6) for treatment. (6) Pump the product water from step (5) into the chelating resin adsorption tower 7 for treatment. (7) The product water from step (6) is pumped into a modified zeolite adsorption tower (8) for treatment to obtain a pure solution.

4. The method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization according to claim 3, characterized in that: In step (1), the hydraulic retention time of the chemical high-salt wastewater desalination crystallization mother liquor in step (1) is 2-4 hours, and the high-density sedimentation tank (1) includes a high-density sedimentation tank conditioning zone (11), a high-density sedimentation tank coagulation zone (12), a high-density sedimentation tank flocculation zone (13), and a high-density sedimentation tank sedimentation zone (14) connected from left to right. A stirring system is provided in the high-density sedimentation tank conditioning zone (11), the high-density sedimentation tank coagulation zone (12), and the high-density sedimentation tank flocculation zone (13), and a dosing system is provided on the high-density sedimentation tank conditioning zone (11). The conditioning and balancing are carried out in the high-density sedimentation tank conditioning zone (11), and the pH value is adjusted to 9-11, and the TDS is 150000-250000 mg / L. The stirring method of the stirring system is stirring with a mixer or aeration stirring, and the stirring is carried out at normal temperature and pressure.

5. The method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization according to claim 3, characterized in that: In step (2), the permeate from step (1) is pumped into the primary reactor (2) with a hydraulic retention time of 1-2 hours. The primary reactor (2) includes, from left to right, a primary reactor conditioning zone (21), a primary reactor micro-electric field treatment zone (22) equipped with a scraper (221), a primary reactor slag storage zone (23), and a primary reactor sedimentation zone (24). Each of the slag storage areas (23) is equipped with a stirring device, and a dosing device is set up in the adjustment area (21) of the primary reactor. The stirring device stirs the slag at normal temperature and pressure. The micro electric field A is arranged in the micro electric field treatment area (22) of the primary reactor. The micro electric field A is equipped with an immersion electrode plate, which is any one or a combination of several of the following: iron electrode plate, aluminum electrode plate, graphite electrode plate, diamond electrode plate, titanium-iridium-tantalum electrode plate, titanium-nickel-cobalt electrode plate, and titanium-ruthenium-iridium electrode plate. The catalyst A is a functionalized ionic liquid.

6. The method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization according to claim 3, characterized in that: In step (3), the permeate from step (2) is pumped into the secondary reactor (3) with a hydraulic retention time of 1-2 hours. The secondary reactor (3) includes a secondary reactor conditioning zone (31), a secondary reactor micro-electric field treatment zone (32), and a secondary reactor sedimentation zone (33) connected sequentially from left to right. The bottom of the secondary reactor micro-electric field treatment zone (32) and the secondary reactor sedimentation zone (33) are connected by a bottom sludge return pipe (34). A stirrer is installed inside the micro-electric field treatment zone (32) of the reactor, and a dosing device is installed on the adjustment zone (31) of the secondary reactor. The stirrer is used for stirring at normal temperature and pressure. The micro-electric field B is arranged in the micro-electric field treatment zone (32) of the secondary reactor. The micro-electric field B is equipped with an immersion electrode plate, which is any one or a combination of several of the following: iron electrode plate, aluminum electrode plate, graphite electrode plate, diamond electrode plate, titanium-iridium-tantalum electrode plate, titanium-nickel-cobalt electrode plate, and titanium-ruthenium-iridium electrode plate. The catalyst B is a sulfonic acid-based ionic liquid.

7. The method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization according to claim 3, characterized in that: In step (4), the permeate from step (3) is pumped into the tertiary reactor (4) with a hydraulic retention time of 1-2 hours. The tertiary reactor (4) includes, from left to right, a first conditioning zone (41), a tertiary reactor micro-electric field treatment zone (42), a second conditioning zone (43), a tertiary reactor sedimentation zone (44), a third conditioning zone (45), and a clarification zone (46). Each zone (45) is equipped with a stirring system, and the first adjustment zone (41), the second adjustment zone (43) and the third adjustment zone (45) are equipped with a dosing system. The stirring system stirs at normal temperature and pressure. The micro electric field C is arranged in the micro electric field treatment zone (42) of the three-stage reactor. The micro electric field C is equipped with an immersion electrode plate, which is any one or a combination of several of the following: iron electrode plate, aluminum electrode plate, graphite electrode plate, diamond electrode plate, titanium-iridium-tantalum electrode plate, titanium-nickel-cobalt electrode plate and titanium-ruthenium-iridium electrode plate.

8. The method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization according to claim 3, characterized in that: In step (5), the filtration device (5) consists of a quartz sand filter and a precision filter. The quartz sand filter and the precision filter are connected in series in a single group, with the quartz sand filter first and the precision filter second. The filtration accuracy of the quartz sand filter is 0.005 to 0.01 mm, and the filtration accuracy of the precision filter is 0.005 to 0.01 μm. The mesoporous adsorption tower (6) consists of a support structure, an adsorption tank, an inlet and outlet system, a regeneration system, and a control system. The adsorption tank is filled with mesoporous-microporous adsorbent. Each adsorption tower consists of 3 to 5 adsorption tanks connected in series, with two in use and one on standby, or three in use and one on standby, or four in use and one on standby. Multiple adsorption towers are connected in parallel. The inlet flow rate of the mesoporous adsorption tower (6) is 0.5 to 2.5 BV.

9. The method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization according to claim 3, characterized in that: In step (6), the chelating resin adsorption tower 7 is composed of a support structure, an adsorption tank, a feeding and discharging system, a regeneration system and a control system. The adsorption tank is filled with chelating adsorbent. The single chelating resin adsorption tower (7) consists of 3 adsorption tanks connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The inlet flow rate of the chelating resin adsorption tower (7) is 0.5 to 2.5 BV.

10. The method for removing impurities from the mother liquor of high-salt chemical wastewater desalination crystallization according to claim 3, characterized in that: The modified zeolite adsorption tower (8) in step (7) consists of a support structure, an adsorption tank, a feed and discharge system, a regeneration system and a control system. The adsorption tank is filled with modified zeolite adsorbent. Each modified zeolite adsorption tower (8) consists of three adsorption tanks connected in series, with two in use and one as a backup. Multiple adsorption towers are connected in parallel. The inlet flow rate of the modified zeolite adsorption tower is 0.5 to 2.5 BV.

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