High-calcium high-fluorine high-salt concentrated water zero-discharge treatment method and system

Abstract

The application relates to a high-calcium high-fluorine high-salt concentrated water zero-discharge treatment method and system, which comprises the following steps: pre-configuring a coagulant for removing fluorine and calcium and modified resin according to the water quality characteristics of high-calcium high-fluorine high-salt concentrated water; feeding the high-calcium high-fluorine high-salt concentrated water into a high-density sedimentation tank, wherein the high-density sedimentation tank comprises a coagulation tank, a flocculation tank and a sedimentation tank which are sequentially connected, coagulant is added into the coagulation sedimentation tank, and polyacrylamide is added into the flocculation tank; feeding supernatant separated from the sedimentation tank into a modified resin adsorption tower, wherein the modified resin adsorption tower is filled with modified resin; performing reverse osmosis treatment on the effluent of the modified resin adsorption tower; and performing evaporation crystallization on concentrated water produced after the reverse osmosis treatment to obtain an industrial sodium chloride product. The application effectively removes fluorine ions and calcium ions in the high-calcium high-fluorine high-salt concentrated water, and finally prepares an industrial sodium chloride product, so that the zero-discharge treatment of the high-calcium high-fluorine high-salt concentrated water is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, and particularly relates to a high-calcium high-fluorine high-salt concentrated water zero-discharge treatment method and system. BACKGROUND

[0002] Industrial wastewater is complex in composition and contains a large amount of impurities such as fluoride ions, calcium ions and sulfate ions. In recent years, more and more industrial enterprises implement zero-discharge treatment of wastewater. After industrial wastewater is concentrated by multiple stages of membranes, the wastewater is reduced in amount, but the high-salt concentrated water produced contains high concentrations of fluoride ions and calcium ions. The treatment of high-fluorine high-calcium high-salt concentrated water is a key technology restricting the zero-discharge of industrial wastewater.

[0003] The excessive fluoride ion content in the high-salt concentrated water reduces the purity of crystalline salt, which does not meet the requirements of GB / T5462-2015 Industrial Salt and GB / T 6009-2014 Industrial Anhydrous Sodium Sulfate, and causes corrosion, scaling and blockage of thermal evaporation equipment. The excessive calcium ion content causes scaling and blockage of membrane materials and equipment, and shortens the service life of the equipment.

[0004] Currently, chemical precipitation and coagulation are mainly used for the treatment of fluorine-containing wastewater. However, the chemical precipitation method has the problems of excessive dosage, difficulty in reducing the content to below 10 mg / L, easy scaling of pipeline equipment and turbid water quality. The coagulation method combined with the chemical precipitation method has the problems of large dosage of a single coagulant, narrow pH value range and large sludge production.

[0005] The double-alkali precipitation method is mainly used for the treatment of high-salt high-calcium wastewater. An appropriate amount of alkali reagent such as sodium carbonate or lime is added to produce a difficultly soluble precipitate to remove most of the calcium ions. The method is simple to operate and has low equipment investment, but has the disadvantages of incomplete removal rate, high required reagent dosage and large sludge production.

[0006] Therefore, it is urgent to develop an economic and efficient zero-discharge treatment process according to the water quality and quantity of high-calcium high-fluorine high-salt concentrated water. SUMMARY

[0007] The present application relates to the technical field of water treatment, and particularly relates to a high-calcium high-fluorine high-salt concentrated water zero-discharge treatment method and system.

[0008] In order to achieve the above-mentioned purpose, the present application provides a high-calcium high-fluorine high-salt concentrated water zero-discharge treatment method, comprising:

[0009] The coagulant for removing fluorine and calcium and the modified resin for removing fluorine and calcium are configured in advance according to the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water, the coagulant is compounded by polyaluminum chloride solution, aluminum chloride solution, polyaluminum sulfate solution, sodium carbonate solution and carboxymethyl cellulose, and the modified resin is prepared by styrene-diethylbenzene resin polymer, polyvinyl alcohol solution, polyacrylate resin, azobisisobutyronitrile, sodium hydroxide solution, chloroacetic acid, isopropyl alcohol and petroleum ether;

[0010] The high-calcium high-fluorine high-salt concentrated water is sent to a high-density sedimentation tank, the high-density sedimentation tank comprises a coagulation tank, a flocculation tank and a sedimentation tank connected in sequence, the coagulant is added into the coagulation sedimentation tank, and polyacrylamide is added into the flocculation tank;

[0011] The supernatant after solid-liquid separation of the sedimentation tank is sent to a modified resin adsorption tower filled with the modified resin;

[0012] The effluent of the modified resin adsorption tower is subjected to reverse osmosis treatment;

[0013] The concentrated water produced after the reverse osmosis treatment is subjected to evaporation crystallization to obtain an industrial sodium chloride product.

[0014] Optionally, the preparation method of the coagulant comprises:

[0015] The polyaluminum chloride solution with a mass percentage of 21-27%, the aluminum chloride solution with a mass percentage of 3-11%, the polyaluminum sulfate solution with a mass percentage of 4-7% and the sodium carbonate solution with a mass percentage of 13-19% are prepared to form a mixed solution in a volume ratio of 5-7:1:2:3-5;

[0016] 0.01-0.05g of the carboxymethyl cellulose is added into each liter of the mixed solution, mechanical stirring is performed at a speed of 45-55 revolutions per minute for 35-67 minutes, and then ultrasonic treatment is performed for 3-7 minutes to prepare the coagulant.

[0017] Optionally, the addition amount of the coagulant is 452-690mg / L, and the addition amount of the polyacrylamide is 0.5-2mg / L.

[0018] Optionally, the residence time of the high-calcium high-fluorine high-salt concentrated water in the coagulation tank, the flocculation tank and the sedimentation tank is 3.1-5.2 minutes, 9.5-12.5 minutes and 15-35 minutes, respectively.

[0019] Optionally, the preparation method of the modified resin comprises:

[0020] The styrene-diethylbenzene resin polymer is selected, and the crosslinking degree is between 8-9%;

[0021] A polyvinyl alcohol solution with a degree of hydrolysis of 79% is placed in a reaction vessel, and 950-1040 mg of styrene-diethylstyrene resin, 67-125 mg of polymethyl acrylate resin and 1.3-5.7 ml of azobisisobutyronitrile are added per liter of the polyvinyl alcohol solution by volume.

[0022] The reactor is heated to 98°C and stirred for 560–670 min at a stirring speed of 55–95 rpm.

[0023] After the reaction is complete, the resin mixture is cooled and filtered, washed 3-5 times with 2% sodium hydroxide solution, 3-5 times with petroleum ether, and 3-5 times with water, and then dried under vacuum at 65°C for 110-130 min and cooled.

[0024] The resin mixture and the chloroacetic acid were placed in the reaction vessel at a mass ratio of 5-6:1 and reacted in the reaction vessel at 45-49°C for 160-180 min. The reaction was terminated by adding the isopropanol at a volume ratio of 10-15 ml / L. The mixture was then cooled and filtered to obtain a solid substance.

[0025] The modified resin is obtained by washing the solid substance 3-5 times with petroleum ether, washing it 3-5 times with water, and then vacuum drying it at 60°C for 3-4 hours.

[0026] Optionally, the modified resin accounts for 85-95% of the total volume of the modified resin adsorption tower, and the high-calcium, high-fluorine, and high-salt concentrated water has a residence time of 36-39 minutes in the modified resin adsorption tower.

[0027] Based on the same inventive concept, this invention also provides a zero-discharge treatment system for high-calcium, high-fluoride, and high-salt concentrated wastewater, comprising:

[0028] The dosing unit is used to pre-prepare coagulants and modified resins for defluorination and calcium removal, specifically targeting the characteristics of high-calcium, high-fluoride, and high-salt concentrated water. The coagulant is composed of polyaluminum chloride solution, aluminum chloride solution, polyaluminum sulfate solution, sodium carbonate solution, and carboxymethyl cellulose. The modified resin is prepared from styrene-diethylstyrene resin polymer, polyvinyl alcohol solution, polymethyl acrylate resin, azobisisobutyronitrile, sodium hydroxide solution, chloroacetic acid, isopropanol, and petroleum ether.

[0029] A high-density sedimentation tank, comprising a coagulation tank, a flocculation tank and a sedimentation tank connected in sequence, is used to sequentially coagulate, flocculate and separate solids and liquids in the high-calcium, high-fluoride and high-salt concentrated water.

[0030] A dosing unit is used to add the coagulant to the coagulation sedimentation tank and to add polyacrylamide to the flocculation tank.

[0031] A modified resin adsorption tower is used for adsorption treatment of supernatant after solid-liquid separation of the precipitation tank, and the modified resin adsorption tower is filled with the modified resin.

[0032] A reverse osmosis membrane is used for reverse osmosis treatment of water outlet of the modified resin adsorption tower.

[0033] An evaporation crystallizer is used for evaporation crystallization of concentrated water produced after the reverse osmosis treatment, to obtain an industrial sodium chloride product.

[0034] Optionally, the preparation method of the coagulant comprises:

[0035] The polyaluminum chloride solution with a mass percentage of 21-27%, the aluminum chloride solution with a mass percentage of 3-11%, the polyaluminum sulfate solution with a mass percentage of 4-7%, and the sodium carbonate solution with a mass percentage of 13-19% are prepared, and a mixed solution is formed in a volume ratio of 5-7:1:2:3-5;

[0036] 0.01-0.05 g of the carboxymethyl cellulose is added per liter of the mixed solution, mechanical stirring is performed at a speed of 45-55 revolutions per minute for 35-67 minutes, and then ultrasonic treatment is performed for 3-7 minutes, to obtain the coagulant.

[0037] Optionally, the preparation method of the modified resin comprises:

[0038] The styrene-divinyl benzene resin polymer with a crosslinking degree of 8-9% is selected;

[0039] The polyvinyl alcohol solution with an alcoholysis degree of 79% is placed in a reaction kettle, 950-1040 mg of the styrene-divinyl benzene resin, 67-125 mg of the methyl acrylate resin, and 1.3-5.7 ml of the azobisisobutyronitrile are added per liter of the polyvinyl alcohol solution in terms of volume;

[0040] The reaction kettle is heated to 98°C, and stirring is performed at a speed of 55-95 revolutions per minute for 560-670 minutes;

[0041] After the reaction is completed, the resin mixture is cooled and filtered, washed with 2% sodium hydroxide solution for 3-5 times, washed with petroleum ether for 3-5 times, washed with clean water for 3-5 times, and vacuum dried at 65°C for 110-130 minutes and cooled;

[0042] The resin mixture and the chloroacetic acid are placed in the reaction kettle in a mass ratio of 5-6:1, and reacted in the reaction kettle at 45-49°C for 160-180 minutes, and the isopropyl alcohol is added in a volume ratio of 10-15 ml / L to terminate the reaction, and the solid material is obtained after cooling and filtration;

[0043] The solid substance is washed 3-5 times by using the petroleum ether, 3-5 times by using clean water, and then dried at 60 DEG C for 3-4 hours under vacuum to obtain the modified resin.

[0044] Optionally, the high calcium high fluorine high salt concentrated water zero discharge treatment system further comprises a first lifting pump, a second lifting pump, a third lifting pump and a high pressure pump, the first lifting pump is used for sending the high calcium high fluorine high salt concentrated water into the high density sedimentation tank, the second lifting pump is used for sending the supernatant after solid-liquid separation of the high calcium high fluorine high salt concentrated water in the sedimentation tank into the modified resin adsorption tower, the high pressure pump is used for sending the high calcium high fluorine high salt concentrated water treated by the modified resin adsorption tower into the reverse osmosis membrane, and the third lifting pump is used for sending the concentrated water produced after the reverse osmosis treatment into the evaporation crystallizer.

[0045] In the high calcium high fluorine high salt concentrated water zero discharge treatment method and system provided by the application, the coagulant for removing fluorine and calcium and the modified resin are configured in advance according to the water quality characteristics of the high calcium high fluorine high salt concentrated water, the fluorine ions and calcium ions in the high calcium high fluorine high salt concentrated water are effectively removed in the high density sedimentation tank and the modified resin adsorption tower, and then the reverse osmosis is used for concentration and the evaporation crystallization is used for the concentrated water, so that the industrial sodium chloride product is finally prepared, and the zero discharge treatment of the high calcium high fluorine high salt concentrated water is realized. BRIEF DESCRIPTION OF DRAWINGS

[0046] Those skilled in the art should understand that the provided drawings are used to better understand the application, and do not constitute any limitation on the scope of the application. Among them:

[0047] Figure 1 The flow chart of the high calcium high fluorine high salt concentrated water zero discharge treatment method provided by an embodiment of the application is shown in the figure.

[0048] Figure 2 The structural schematic diagram of the high calcium high fluorine high salt concentrated water zero discharge treatment system provided by an embodiment of the application is shown in the figure.

[0049] Among them:

[0050] 1-First lifting pump; 2-High density sedimentation tank; 3-Dosing unit; 4-Coagulant; 5-Second lifting pump; 6-Modified resin adsorption tower; 7-Modified resin; 8-High pressure pump; 9-Reverse osmosis membrane; 10-Third lifting pump; 11-Evaporation crystallizer. DETAILED DESCRIPTION

[0051] In order to make the objects, advantages and features of the present application more clearly, the following further describes the present application in conjunction with the drawings and specific embodiments. It should be noted that the drawings are very simplified and all use non-precise proportions, only for the purpose of facilitating and clearly assisting the description of the embodiments of the present application. In order to make the objects, features and advantages of the present application more obvious and easy to understand, please refer to the drawings. It should be understood that the structures, proportions, sizes, etc. shown in the drawings attached to the present specification are only used to cooperate with the content disclosed in the specification, so that those skilled in the art can understand and read, and are not used to limit the conditions of the implementation of the present application. Any modification of structure, change of proportion relationship or adjustment of size, as long as it is the same or similar to the effect and purpose that can be achieved by the present application, should still fall within the scope of the technology disclosed by the present application.

[0052] As used in the present application, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise. As used in the present application, the term "or" is generally employed in its sense of "and / or" unless the content clearly dictates otherwise. As used in the present application, the term "several" is generally employed in its sense of "at least one" unless the content clearly dictates otherwise. As used in the present application, the term "at least two" is generally employed in its sense of "two or more" unless the content clearly dictates otherwise. In addition, the terms "first," "second," "third," are used only for the purpose of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first," "second," "third" can be explicitly or implicitly included one or at least two features.

[0053] In the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be the connection inside two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0054] Please refer to Figure 1 and Figure 2 The embodiment provides a high-calcium high-fluorine high-salt concentrated water zero-discharge treatment method, which comprises the following steps:

[0055] S1, the coagulant 4 and the modified resin 7 used for removing fluorine and calcium are configured in advance according to the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water, the coagulant 4 is compounded by polyaluminum chloride solution, aluminum chloride solution, polyaluminum sulfate solution, sodium carbonate solution and carboxymethyl cellulose, and the modified resin 7 is prepared by styrene-diethyl styrene resin polymer, polyvinyl alcohol solution, polyacrylate resin, azobisisobutyronitrile, sodium hydroxide solution, chloroacetic acid, isopropyl alcohol and petroleum ether;

[0056] S2, the high-calcium high-fluorine high-salt concentrated water is sent into the high-density sedimentation tank 2, the high-density sedimentation tank 2 includes a coagulation tank, a flocculation tank and a sedimentation tank connected in sequence, the coagulant 4 is added into the coagulation sedimentation tank, and polyacrylamide is added into the flocculation tank;

[0057] S3, the supernatant after the solid-liquid separation of the sedimentation tank is sent into the modified resin adsorption tower 6, and the modified resin 7 is filled in the modified resin adsorption tower 6;

[0058] S4, the effluent of the modified resin adsorption tower 6 is treated by reverse osmosis;

[0059] S5, the concentrated water produced after the reverse osmosis treatment is evaporated and crystallized to obtain an industrial sodium chloride product.

[0060] By configuring the coagulant 4 and the modified resin 7 used for removing fluorine and calcium in advance according to the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water, the fluorine ions and calcium ions in the high-calcium high-fluorine high-salt concentrated water are effectively removed in the high-density sedimentation tank 2 and the modified resin adsorption tower 6, and then the concentrated water is concentrated by reverse osmosis and evaporated and crystallized, so that the industrial sodium chloride product is finally prepared, and the zero discharge treatment of the high-calcium high-fluorine high-salt concentrated water is realized.

[0061] Firstly, S1 is performed, the coagulant 4 and the modified resin 7 used for removing fluorine and calcium are configured in advance according to the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water, the coagulant 4 is compounded by polyaluminum chloride solution, aluminum chloride solution, polyaluminum sulfate solution, sodium carbonate solution and carboxymethyl cellulose, and the modified resin 7 is prepared by styrene-diethyl styrene resin polymer, polyvinyl alcohol solution, polyacrylate resin, azobisisobutyronitrile, sodium hydroxide solution, chloroacetic acid, isopropyl alcohol and petroleum ether.

[0062] In the embodiment, the preparation method of the coagulant 4 includes:

[0063] The polyaluminum chloride solution with a mass percentage of 21-27%, the aluminum chloride solution with a mass percentage of 3-11%, the polyaluminum sulfate solution with a mass percentage of 4-7% and the sodium carbonate solution with a mass percentage of 13-19% are prepared, and a mixed solution is formed by the volume ratio of 5-7:1:2:3-5;

[0064] 0.01-0.05 g of carboxymethyl cellulose is added to each liter of the mixed solution, mechanical stirring is performed at a speed of 45-55 rpm for 35-67 min, and then ultrasonic stirring is performed for 3-7 min to obtain the coagulant 4.

[0065] The preparation method of the modified resin 7 comprises:

[0066] The styrene-divinylbenzene resin polymer is selected, and the crosslinking degree is between 8-9%;

[0067] The polyvinyl alcohol solution with an alcoholysis degree of 79% is placed in a reaction kettle, 950-1040 mg of styrene-divinylbenzene resin, 67-125 mg of methyl acrylate resin and 1.3-5.7 ml of azobisisobutyronitrile are added to each liter of the polyvinyl alcohol solution in terms of volume;

[0068] The reaction kettle is heated to 98°C under a nitrogen protective atmosphere, and stirring is performed at a speed of 55-95 rpm for 560-670 min;

[0069] After the reaction is completed, the resin mixture is cooled and filtered, washed with 2% sodium hydroxide solution for 3-5 times, washed with petroleum ether for 3-5 times, washed with clean water for 3-5 times, and dried at 65°C under vacuum for 110-130 min and cooled;

[0070] The resin mixture and chloroacetic acid are placed in a reaction kettle in a mass ratio of 5-6:1, and the reaction is performed in the reaction kettle at 45-49°C for 160-180 min, isopropanol is added in a volume ratio of 10-15 ml / L to terminate the reaction, and the solid material is obtained after cooling and filtration;

[0071] The solid material is washed with petroleum ether for 3-5 times, washed with clean water for 3-5 times, and dried at 60°C under vacuum for 3-4 h to obtain the modified resin 7. The modified resin 7 is a cationic resin, and the total exchange capacity is 3.1-4.9 mmol / g. The modified resin 7 has strong adsorption and displacement capacity for fluoride ions and calcium ions.

[0072] Then, S2 is performed, and the high-calcium high-fluorine high-salt concentrated water is sent to a high-density sedimentation tank 2. The high-density sedimentation tank 2 comprises a coagulation tank, a flocculation tank and a sedimentation tank connected in sequence. The coagulant 4 is added to the coagulation sedimentation tank, and polyacrylamide is added to the flocculation tank.

[0073] In this embodiment, the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water are as follows: the calcium hardness is 75-256 mg / L, the total fluorine is 21-47 mg / L, and the conductivity is 41210-63240 μs / cm.

[0074] The high-calcium high-fluorine high-salt concentrated water enters a high-density sedimentation tank 2 through a primary lifting pump 1. The high-density sedimentation tank 2 is divided into a coagulation tank, a flocculation tank and a sedimentation tank. A dosing unit 3 is respectively provided with a coagulant 4 and polyacrylamide. The high-calcium high-fluorine high-salt concentrated water first enters the coagulation tank. The dosing unit 3 adds the coagulant 4 into the coagulation tank. The adding amount is 452-690 mg / L. The stirring speed of the coagulation tank is 75-105 r / min. The residence time of the high-calcium high-fluorine high-salt concentrated water in the coagulation tank is 3.1-5.2 min. Then the high-calcium high-fluorine high-salt concentrated water enters the flocculation tank. The dosing unit 3 adds the polyacrylamide into the flocculation tank. The adding amount of the polyacrylamide is 0.5-2 mg / L. The hydraulic residence time of the flocculation tank is 9.5-12.5 min. The flocculation tank is provided with a flow guide cylinder. The flow speed in the barrel of the flow guide cylinder is 0.5-0.9 m / s. The flow speed outside the barrel of the flow guide cylinder is 0.1-0.2 m / s. The sludge return flow is 3-5%. The high-calcium high-fluorine high-salt concentrated water flows into the sedimentation tank from the water outlet area of the flocculation tank. The inclined pipe in the sedimentation tank has a diameter of 65-85 mm. The inclined angle of the inclined pipe is 59°. The inclined length of the inclined pipe is 1200-1450 mm. The surface load of the inclined pipe is 15.5-17.5 m 3 / m 2 ·h. The height of the clear water area is 0.6-0.9 m. The height of the sludge storage area is 0.7-0.8 m. The residence time is 15-35 min. After the high-density sedimentation tank 2, the calcium hardness in the supernatant is 16-31 mg / L. The total fluorine is 6-12 mg / L. The conductivity is 42330-66240 μs / cm.

[0075] In this embodiment, the sludge in the sedimentation tank can be partially returned to the flocculation tank by a return sludge pump to reuse the polyacrylamide. The remaining part can be discharged into a sludge storage tank by a sludge pump and then transported out after dewatering by a plate and frame filter press.

[0076] Then S3 is performed. The supernatant after the solid-liquid separation in the sedimentation tank is sent into a modified resin adsorption tower 6. The modified resin adsorption tower 6 is filled with modified resin 7.

[0077] In this embodiment, the supernatant after the solid-liquid separation in the sedimentation tank enters the modified resin adsorption tower 6 through a secondary lifting pump 5. The modified resin 7 is placed in the modified resin adsorption tower 6. The modified resin 7 accounts for 85-95% of the volume of the entire modified resin adsorption tower 6. The residence time of the supernatant in the modified resin adsorption tower 6 is 36-39 min. After the modified resin adsorption tower 6, the calcium hardness in the high-calcium high-fluorine high-salt concentrated water is 3-10 mg / L. The total fluorine is 1-4 mg / L. The conductivity is 42330-66240 μs / cm.

[0078] Then, S4 is performed to perform reverse osmosis treatment on the effluent of the modified resin adsorption tower 6. In the embodiment, the effluent of the modified resin adsorption tower 6 can be pumped into the reverse osmosis membrane 9 by the high-pressure pump 8, the pressure of the high-pressure pump 8 is 56-58 MPa, and the water production rate of the reverse osmosis membrane 9 is 51-53%. After the treatment of the reverse osmosis membrane 9, the produced water is directly reused for production.

[0079] Finally, S5 is performed to perform evaporation crystallization on the concentrated water produced after the reverse osmosis treatment to obtain an industrial sodium chloride product. In the embodiment, the concentrated water can be pumped into the evaporation crystallizer 11 by the three-stage lifting pump 10, the evaporation temperature is 88-95℃, the compressor pressure ratio is 1.5-2.5, and the industrial sodium chloride product is finally prepared by evaporation crystallization.

[0080] The produced industrial sodium chloride product has a sodium chloride content (mass percentage) of >97.5%, a moisture content of <0.8%, an insoluble substance content of <0.2%, a calcium and magnesium content of <0.6%, and a sulfate ion content of <0.9%, which meets the industrial dry salt level 2 standard stipulated in the Industrial Salt (GB / T 5462-2015) of the People's Republic of China.

[0081] Based on the same inventive concept, the embodiment of the present application also provides a high-calcium high-fluorine high-salt concentrated water zero-discharge treatment system, which comprises:

[0082] The dosing unit is used for pre-configuring the coagulant 4 for defluorination and decalcification and the modified resin 7 according to the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water, the coagulant 4 is compounded by polyaluminum chloride solution, aluminum chloride solution, polyaluminum sulfate solution, sodium carbonate solution and carboxymethyl cellulose, and the modified resin 7 is prepared by styrene-diethyl styrene resin polymer, polyvinyl alcohol solution, polyacrylate resin, azobis isobutyronitrile, sodium hydroxide solution, chloroacetic acid, isopropyl alcohol and petroleum ether;

[0083] The high-density sedimentation tank 2 comprises a coagulation tank, a flocculation tank and a sedimentation tank connected in sequence, and is used for sequentially performing coagulation, flocculation and solid-liquid separation treatment on the high-calcium high-fluorine high-salt concentrated water;

[0084] The dosing unit 3 is used for adding the coagulant 4 into the coagulation sedimentation tank and adding polyacrylamide into the flocculation tank;

[0085] The modified resin adsorption tower 6 is used for adsorption treatment on the supernatant after the solid-liquid separation of the sedimentation tank, and the modified resin adsorption tower 6 is filled with the modified resin 7;

[0086] The reverse osmosis membrane 9 is used for reverse osmosis treatment on the effluent of the modified resin adsorption tower 6;

[0087] The evaporation crystallizer 11 is used for evaporation crystallization on the concentrated water produced after the reverse osmosis treatment to obtain a sodium chloride product.

[0088] Preferably, the preparation method of the coagulant 4 comprises:

[0089] Forming a mixed solution with 21-27% of polyaluminum chloride solution, 3-11% of aluminum chloride solution, 4-7% of polyaluminum sulfate solution and 13-19% of sodium carbonate solution by mass percentage, and 5-7:1:2:3-5 by volume ratio;

[0090] Adding 0.01-0.05g of carboxymethyl cellulose per liter of the mixed solution, stirring at a mechanical stirring speed of 45-55rpm for 35-67min, and then ultrasonicating for 3-7min to obtain the coagulant 4.

[0091] Preferably, the preparation method of the modified resin 7 comprises:

[0092] Selecting a styrene-divinyl benzene resin polymer with a crosslinking degree of 8-9%;

[0093] Placing a polyvinyl alcohol solution with an alcoholysis degree of 79% in a reaction kettle, and adding 950-1040mg of styrene-divinyl benzene resin, 67-125mg of methyl acrylate resin and 1.3-5.7ml of azobisisobutyronitrile per liter of the polyvinyl alcohol solution by volume;

[0094] Heating the reaction kettle to 98℃, and stirring for 560-670min at a stirring speed of 55-95rpm;

[0095] After the reaction is completed, cooling and suction-filtering the resin mixture, washing it with 2% sodium hydroxide solution for 3-5 times, petroleum ether for 3-5 times, and clean water for 3-5 times, and vacuum drying at 65℃ for 110-130min, and cooling;

[0096] Placing the resin mixture and chloroacetic acid in a reaction kettle at a mass ratio of 5-6:1, reacting in the reaction kettle at 45-49℃ for 160-180min, adding isopropyl alcohol to terminate the reaction at a volume ratio of 10-15ml / L, and cooling and suction-filtering to obtain solid material;

[0097] Washing the solid material with petroleum ether for 3-5 times, clean water for 3-5 times, and vacuum drying at 60℃ for 3-4h to obtain the modified resin 7.

[0098] Preferably, the high-calcium high-fluorine high-salt concentrated water zero discharge treatment system further comprises a first lifting pump 1, a second lifting pump 5, a third lifting pump 10, and a high-pressure pump 8, the first lifting pump 1 is used to send the high-calcium high-fluorine high-salt concentrated water into the high-density sedimentation tank 2, the second lifting pump 5 is used to send the supernatant after the solid-liquid separation of the sedimentation tank into the modified resin adsorption tower 6, the high-pressure pump 8 is used to send the high-calcium high-fluorine high-salt concentrated water treated by the modified resin adsorption tower 6 into the reverse osmosis membrane 9, and the third lifting pump 10 is used to send the concentrated water produced after the reverse osmosis treatment into the evaporation crystallizer 11.

[0099] The technical concept of the present application is further illustrated in the following three specific embodiments.

[0100] Embodiment one

[0101] In this embodiment, the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water are: calcium hardness of 136 mg / L, total fluorine of 35 mg / L, and conductivity of 57230 μs / cm.

[0102] The preparation method of the coagulant 4 comprises:

[0103] A polyaluminum chloride solution with a mass percentage of 23%, an aluminum chloride solution with a mass percentage of 4%, a polyaluminum sulfate solution with a mass percentage of 6%, and a sodium carbonate solution with a mass percentage of 17% are prepared to form a mixed solution in a volume ratio of 7:1:2:4;

[0104] 0.02 g of carboxymethyl cellulose is added to each liter of the mixed solution, mechanical stirring is performed at a speed of 50 revolutions / min for 50 min, and then ultrasonic treatment is performed for 5 min to obtain the coagulant 4.

[0105] The preparation method of the modified resin 7 comprises:

[0106] A styrene-divinylbenzene resin polymer with a crosslinking degree of 9% is selected;

[0107] A polyvinyl alcohol solution with an alcoholysis degree of 79% is placed in a reaction kettle, 990 mg of styrene-divinylbenzene resin, 59 mg of polyacrylate resin, and 3.1 ml of azobisisobutyronitrile are added to each liter of the polyvinyl alcohol solution in terms of volume;

[0108] The reaction kettle is heated to 98°C under a nitrogen protective atmosphere, and stirring is performed at a speed of 75 revolutions / min for 590 min;

[0109] After the reaction is completed, the resin mixture is cooled and suction-filtered, washed with a 2% sodium hydroxide solution for 4 times, washed with petroleum ether for 4 times, washed with clean water for 4 times, and vacuum dried at 65°C for 121 min and then cooled;

[0110] The resin mixture and chloroacetic acid are placed in a reaction kettle at a mass ratio of 6:1, and reacted in the reaction kettle at 47℃ for 170 min. Isopropyl alcohol is added to terminate the reaction at a volume ratio of 12 ml / L, and the solid material is obtained by cooling and filtration.

[0111] The solid material is washed with petroleum ether 4 times and with water 4 times, and then dried in a vacuum at 60℃ for 3 h to obtain the modified resin 7. The modified resin 7 is a cationic resin with a total exchange capacity of 3.9 mmol / g, and has strong adsorption and displacement capacity for fluoride ions and calcium ions.

[0112] The high calcium, high fluorine and high salt concentrated water is fed into the high-density sedimentation tank 2 through a primary booster pump 1. The high-density sedimentation tank 2 is divided into a coagulation tank, a flocculation tank and a sedimentation tank. The dosing unit 3 is provided with a coagulant 4 and polyacrylamide. The high calcium, high fluorine and high salt concentrated water is first fed into the coagulation tank, and the coagulant 4 is added into the coagulation tank through the dosing unit 3. The addition amount of the coagulant 4 is 511 mg / L, the stirring speed of the coagulation tank is 83 rpm, and the residence time of the high calcium, high fluorine and high salt concentrated water in the coagulation tank is 3.9 min. Then, the high calcium, high fluorine and high salt concentrated water is fed into the flocculation tank, and the polyacrylamide is added into the flocculation tank through the dosing unit 3. The addition amount of the polyacrylamide is 1 mg / L, the hydraulic residence time of the flocculation tank is 11 min, and the flocculation tank is provided with a draft tube. The flow rate in the draft tube is 0.7 m / s, the flow rate outside the draft tube is 0.1 m / s, and the sludge return flow is 3-5%. The high calcium, high fluorine and high salt concentrated water flows into the sedimentation tank from the effluent zone of the flocculation tank. The inclined pipe in the sedimentation tank has a diameter of 75 mm, an inclination angle of 59°, an inclined length of 1250 mm, a surface load of 15.9 m 3 / m 2 ·h, a clear water zone height of 0.7 m, a sludge storage zone height of 0.8 m, and a residence time of 28 min. After the high-density sedimentation tank 2, the calcium hardness in the supernatant is 23 mg / L, the total fluorine is 8 mg / L, and the conductivity is 58020 μs / cm.

[0113] In this embodiment, the supernatant after the solid-liquid separation in the sedimentation tank is fed into the modified resin adsorption tower 6 through a secondary booster pump 5. The modified resin 7 is placed in the modified resin adsorption tower 6. The modified resin 7 accounts for 90% of the volume of the modified resin adsorption tower 6. The residence time of the supernatant in the modified resin adsorption tower 6 is 37 min. After the modified resin adsorption tower 6, the calcium hardness in the high calcium, high fluorine and high salt concentrated water is 5 mg / L, the total fluorine is 3 mg / L, and the conductivity is 58070 μs / cm.

[0114] The high-pressure pump 8 then pumps the effluent of the modified resin adsorption tower 6 into the reverse osmosis membrane 9, the pressure of the high-pressure pump 8 is 56 MPa, and the water production rate of the reverse osmosis membrane 9 is 52%. After being treated by the reverse osmosis membrane 9, the produced water is directly reused for production. The concentrated water produced after the reverse osmosis treatment is pumped into the evaporation crystallizer 11 by the three-stage booster pump 10, the evaporation temperature is 95°C, the compressor pressure ratio is 1.9, and the industrial sodium chloride product is finally prepared by evaporation crystallization.

[0115] The produced industrial sodium chloride product has a sodium chloride content (mass percentage) of 97.6%, a moisture content of 0.7%, an insoluble substance content of 0.1%, a calcium and magnesium content of 0.5%, and a sulfate ion content of 0.7%, which meets the industrial dry salt level II standard specified in the national standard of the People's Republic of China, Industrial Salt (GB / T 5462-2015).

[0116] Example Two

[0117] In this embodiment, the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water are as follows: calcium hardness is 251 mg / L, total fluorine is 42 mg / L, and electrical conductivity is 61110 μs / cm.

[0118] The preparation method of the coagulant 4 includes:

[0119] A polyaluminum chloride solution with a mass percentage of 27%, an aluminum chloride solution with a mass percentage of 11%, a polyaluminum sulfate solution with a mass percentage of 7%, and a sodium carbonate solution with a mass percentage of 19% are prepared to form a mixed solution in a volume ratio of 7:1:2:4;

[0120] 0.05 g of carboxymethyl cellulose is added to each liter of the mixed solution, the mechanical stirring speed is 55 revolutions / min, stirring is performed for 67 min, and then ultrasonic treatment is performed for 7 min to obtain the coagulant 4.

[0121] The preparation method of the modified resin 7 includes:

[0122] A styrene-divinylbenzene resin polymer with a crosslinking degree of 9% is selected;

[0123] A polyvinyl alcohol solution with an alcoholysis degree of 79% is placed in a reaction kettle, 1040 mg of styrene-divinylbenzene resin, 125 mg of polyacrylate resin, and 5.7 ml of azobisisobutyronitrile are added to each liter of the polyvinyl alcohol solution in terms of volume;

[0124] The reaction kettle is heated to 98°C under a nitrogen protective atmosphere, stirring is performed for 670 min, and the stirring speed is 85 revolutions / min;

[0125] After the reaction is completed, the resin mixture is cooled and suction-filtered, washed with a 2% sodium hydroxide solution for 5 times, washed with petroleum ether for 5 times, washed with clean water for 5 times, and vacuum dried at 65°C for 121 min, and then cooled.

[0126] The resin mixture and chloroacetic acid were placed in a reaction kettle at a mass ratio of 6:1, reacted in the reaction kettle at 49°C for 180 min, and terminated by adding isopropyl alcohol at a volume ratio of 15 ml / L, and then cooled and filtered to obtain solid substances;

[0127] The solid substances were washed with petroleum ether 4 times and with water 4 times, and then dried in a vacuum at 60°C for 4 h to obtain modified resin 7. The modified resin 7 is a cationic resin with a total exchange capacity of 3.8 mmol / g and strong adsorption displacement capacity for fluoride ions and calcium ions.

[0128] The high-calcium, high-fluorine and high-salt concentrated water enters a high-density sedimentation tank 2 through a primary booster pump 1. The high-density sedimentation tank 2 is divided into a coagulation tank, a flocculation tank and a sedimentation tank. A dosing unit 3 is provided with a coagulant 4 and polyacrylamide. The high-calcium, high-fluorine and high-salt concentrated water first enters the coagulation tank, the dosing unit 3 adds the coagulant 4 into the coagulation tank, the addition amount is 690 mg / L, the stirring speed of the coagulation tank is 105 r / min, and the residence time of the high-calcium, high-fluorine and high-salt concentrated water in the coagulation tank is 5.2 min. Then the high-calcium, high-fluorine and high-salt concentrated water enters the flocculation tank, the dosing unit 3 adds polyacrylamide into the flocculation tank, the addition amount of the polyacrylamide is 2 mg / L, the hydraulic retention time of the flocculation tank is 12.5 min, the flocculation tank is provided with a flow guide cylinder, the flow speed in the cylinder is 0.9 m / s, the flow speed outside the cylinder is 0.2 m / s, and the sludge return flow is 5%. The high-calcium, high-fluorine and high-salt concentrated water flows into the sedimentation tank from the effluent area of the flocculation tank, the inclined pipe has a diameter of 85 mm, an inclination angle of 59° and an inclined length of 1450 mm, the surface load is 17.5 m 3 / m 2 ·h, the height of the clear water area is 0.9 m, the height of the sludge storage area is 0.8 m, and the residence time is 35 min. After passing through the high-density sedimentation tank 2, the calcium hardness in the supernatant is 29 mg / L, the total fluorine is 10 mg / L, and the conductivity is 62340 μs / cm.

[0129] In this embodiment, the supernatant after solid-liquid separation in the sedimentation tank enters a modified resin adsorption tower 6 through a secondary booster pump 5, the modified resin adsorption tower 6 is provided with modified resin 7, the modified resin 7 accounts for 95% of the volume of the modified resin adsorption tower 6, and the residence time of the supernatant in the modified resin adsorption tower 6 is 39 min. After passing through the modified resin adsorption tower 6, the calcium hardness in the high-calcium, high-fluorine and high-salt concentrated water is 5 mg / L, the total fluorine is 3 mg / L, and the conductivity is 63000 μs / cm.

[0130] The high-pressure pump 8 then pumps the effluent of the modified resin adsorption tower 6 into the reverse osmosis membrane 9, the pressure of the high-pressure pump 8 is 58 MPa, and the water production rate of the reverse osmosis membrane 9 is 53%. After being treated by the reverse osmosis membrane 9, the produced water is directly reused for production. The concentrated water produced after the reverse osmosis treatment is pumped into the evaporation crystallizer 11 by the three-stage booster pump 10, the evaporation temperature is 92℃, the compressor pressure ratio is 3.1, and the industrial sodium chloride product is finally prepared by evaporation crystallization.

[0131] The industrial sodium chloride product produced has a sodium chloride content (mass percentage) of 97.7%, a moisture content of 0.6%, an insoluble substance content of 0.1%, a calcium and magnesium content of 0.5%, and a sulfate ion content of 0.7%, which meets the industrial dry salt level 2 standard or above specified in the national standard of the People's Republic of China, Industrial Salt (GB / T 5462-2015).

[0132] Example Three

[0133] In this embodiment, the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water are as follows: calcium hardness is 89 mg / L, total fluorine is 25 mg / L, and conductivity is 49321 μs / cm.

[0134] The preparation method of the coagulant 4 includes:

[0135] A polyaluminum chloride solution with a mass percentage of 22%, an aluminum chloride solution with a mass percentage of 9%, a polyaluminum sulfate solution with a mass percentage of 5%, and a sodium carbonate solution with a mass percentage of 15% are prepared to form a mixed solution in a volume ratio of 6:1:2:3;

[0136] 0.01 g of carboxymethyl cellulose is added to each liter of the mixed solution, the mechanical stirring speed is 48 revolutions / min, stirring is performed for 42 min, and then ultrasonic treatment is performed for 4 min to obtain the coagulant 4.

[0137] The preparation method of the modified resin 7 includes:

[0138] A styrene-divinylbenzene resin polymer with a crosslinking degree of 8% is selected;

[0139] A polyvinyl alcohol solution with an alcoholysis degree of 79% is placed in a reaction kettle, 967 mg of styrene-divinylbenzene resin, 71 mg of polyacrylate resin, and 2.5 ml of azobisisobutyronitrile are added to each liter of the polyvinyl alcohol solution in terms of volume;

[0140] The reaction kettle is heated to 98℃ under a nitrogen protective atmosphere, stirring is performed for 556 min, and the stirring speed is 68 revolutions / min;

[0141] After the reaction is completed, the resin mixture is cooled and suction-filtered, washed with a 2% sodium hydroxide solution for 3 times, washed with petroleum ether for 3 times, washed with clean water for 3 times, and vacuum dried at 65℃ for 115 min and then cooled;

[0142] The resin mixture and chloroacetic acid were placed in a reaction kettle at a mass ratio of 5:1, reacted in the reaction kettle at 45℃ for 160 min, terminated by adding isopropyl alcohol at a volume ratio of 11 ml / L, and cooled and filtered to obtain solid material;

[0143] The solid material was washed with petroleum ether 3 times and clean water 3 times, and dried at 60℃ under vacuum for 3 h to obtain modified resin 7. The modified resin 7 was a cationic resin with a total exchange capacity of 3.4 mmol / g and strong adsorption displacement capacity for fluoride ions and calcium ions.

[0144] The high-calcium, high-fluorine and high-salt concentrated water entered the high-density sedimentation tank 2 through the first-stage lifting pump 1. The high-density sedimentation tank 2 was divided into a coagulation tank, a flocculation tank and a sedimentation tank. The dosing unit 3 was respectively provided with a coagulant 4 and polyacrylamide. The high-calcium, high-fluorine and high-salt concentrated water first entered the coagulation tank. The dosing unit 3 added the coagulant 4 into the coagulation tank. The addition amount was 472 mg / L. The stirring speed of the coagulation tank was 78 r / min. The residence time of the high-calcium, high-fluorine and high-salt concentrated water in the coagulation tank was 3.5 min. Then, the high-calcium, high-fluorine and high-salt concentrated water entered the flocculation tank. The dosing unit 3 added polyacrylamide into the flocculation tank. The addition amount of the polyacrylamide was 0.7 mg / L. The hydraulic retention time of the flocculation tank was 10 min. The flocculation tank was provided with a flow guide cylinder. The flow rate in the cylinder was 0.5 m / s. The flow rate outside the cylinder was 0.1 m / s. The sludge return flow was 3-5%. The high-calcium, high-fluorine and high-salt concentrated water flowed into the sedimentation tank from the effluent zone of the flocculation tank. The inclined pipe had a diameter of 67 mm. The inclined angle of the inclined pipe was 59 degrees. The inclined length of the inclined pipe was 1212 mm. The surface load was 15.5 m3 / m2·h. The height of the clear water zone was 0.6 m. The height of the sludge storage zone was 0.7 m. The residence time was 21 min. After the high-density sedimentation tank 2, the calcium hardness in the supernatant was 18 mg / L. The total fluorine was 7 mg / L. The conductivity was 43581 μs / cm.

[0145] In this embodiment, the supernatant after the solid-liquid separation of the sedimentation tank entered the modified resin adsorption tower 6 through the second-stage lifting pump 5. The modified resin adsorption tower 6 was provided with the modified resin 7. The modified resin 7 accounted for 87% of the volume of the modified resin adsorption tower 6. The residence time of the supernatant in the modified resin adsorption tower 6 was 36 min. After the modified resin adsorption tower 6, the calcium hardness in the high-calcium, high-fluorine and high-salt concentrated water was 4 mg / L. The total fluorine was 2 mg / L. The conductivity was 49521 μs / cm.

[0146] Then, the high-pressure pump 8 pumped the effluent of the modified resin adsorption tower 6 into the reverse osmosis membrane 9. The pressure of the high-pressure pump 8 was 56 MPa. The water production rate of the reverse osmosis membrane 9 was 51%. After the treatment of the reverse osmosis membrane 9, the produced water was directly reused for production. The tertiary-stage lifting pump 10 pumped the concentrated water produced after the reverse osmosis treatment into the evaporation crystallizer 11. The evaporation temperature was 91℃. The compressor pressure ratio was 1.8. Through the evaporation crystallization, the industrial sodium chloride product was finally prepared.

[0147] The produced industrial sodium chloride product has a sodium chloride content (mass percentage) of 97.7%, a moisture content of 0.7%, insoluble substances of 0.15%, a calcium and magnesium content of 0.5%, and sulfate ions of 0.8%, which meets the industrial dry salt level 2 standard or above in the national standard of the People's Republic of China, Industrial Salt (GB / T 5462-2015).

[0148] In conclusion, the embodiment of the present application provides a high-calcium high-fluorine high-salt concentrated water zero-discharge treatment method and system. The coagulant 4 for removing fluorine and calcium and the modified resin 7 are pre-configured according to the water quality characteristics of the high-calcium high-fluorine high-salt concentrated water, the fluorine ions and calcium ions in the high-calcium high-fluorine high-salt concentrated water are effectively removed in the high-density sedimentation tank 2 and the modified resin adsorption tower 6, and then the reverse osmosis is used for concentration and evaporation crystallization of the concentrated water, so that the industrial sodium chloride product is finally prepared, and the zero-discharge treatment of the high-calcium high-fluorine high-salt concentrated water is realized.

[0149] In addition, it should be appreciated that, although the present application has been disclosed above with reference to the preferred embodiments, the above embodiments are not intended to limit the present application. For any person skilled in the art, many possible changes and modifications or equivalent embodiments of the above disclosed technical content can be made without departing from the scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the content of the present application, still belongs to the protection scope of the present application.

Claims

1. A high calcium, high fluorine, high salt concentrated water zero discharge treatment method, characterized in that, The application relates to a method for removing fluorine and calcium from high-calcium high-fluorine high-salt concentrated water. The high-calcium high-fluorine high-salt concentrated water is sent into a high-density sedimentation tank, the high-density sedimentation tank comprises a coagulation tank, a flocculation tank and a sedimentation tank which are sequentially connected, the coagulant is added into the coagulation tank, and polyacrylamide is added into the flocculation tank; The supernatant after solid-liquid separation of the sedimentation tank is sent into a modified resin adsorption tower filled with the modified resin; The effluent of the modified resin adsorption tower is subjected to reverse osmosis treatment; The concentrated water produced after the reverse osmosis treatment is subjected to evaporation crystallization to obtain an industrial sodium chloride product; The preparation method of the modified resin comprises the following steps: The styrene-divinylbenzene resin polymer is selected, and the crosslinking degree is between 8-9%; The polyvinyl alcohol solution with an alcoholysis degree of 79% is placed in a reaction kettle, 950-1040 mg of the styrene-divinylbenzene resin, 67-125 mg of the polyacrylate resin and 1.3-5.7 ml of the azobisisobutyronitrile are added into one liter of the polyvinyl alcohol solution in volume; The reaction kettle is heated to 98 DEG C, and stirring is carried out at a stirring speed of 55-95 revolutions per minute for 560-670 minutes; After the reaction is completed, the resin mixture is cooled and filtered, washed with 2% sodium hydroxide solution for 3-5 times, petroleum ether for 3-5 times, clean water for 3-5 times, and vacuum dried at 65 DEG C for 110-130 minutes and cooled; The resin mixture and the chloroacetic acid are placed in the reaction kettle at a mass ratio of 5-6:1, and the reaction is carried out in the reaction kettle at 45-49 DEG C for 160-180 minutes; the isopropyl alcohol is added in a volume ratio of 10-15 ml / L to terminate the reaction, and the solid material is obtained after cooling and filtering; The solid material is washed with the petroleum ether for 3-5 times, clean water for 3-5 times, and the modified resin is obtained after vacuum drying at 60 DEG C for 3-4 hours. The preparation method of the coagulant comprises the following steps:

2. The high calcium, high fluorine, high salt concentrated water zero discharge treatment method according to claim 1, characterized in that, The polyaluminum chloride solution with a mass percentage of 21-27%, the aluminum chloride solution with a mass percentage of 3-11%, the polyaluminum sulfate solution with a mass percentage of 4-7% and the sodium carbonate solution with a mass percentage of 13-19% are prepared, and a mixed solution is formed in a volume ratio of 5-7:1:2:3-5; 0.01-0.05 g of the carboxymethyl cellulose is added into one liter of the mixed solution, mechanical stirring is carried out at a speed of 45-55 revolutions per minute for 35-67 minutes, and then ultrasonic treatment is carried out for 3-7 minutes to obtain the coagulant. The adding amount of the coagulant is 452-690 mg / L, and the adding amount of the polyacrylamide is 0.5-2 mg / L.

3. The high calcium, high fluorine, high salt concentrated water zero discharge treatment method according to claim 1 or 2, characterized in that, ​ 4. The high calcium, high fluorine, high salt concentrated water zero discharge treatment method according to claim 1, characterized in that, The residence time of the high-calcium high-fluorine high-salt concentrated water in the coagulation tank, the flocculation tank and the sedimentation tank is 3.1-5.2 min, 9.5-12.5 min and 15-35 min respectively.

5. The high calcium, high fluorine, high salt concentrated water zero discharge treatment method according to claim 1, characterized in that, The modified resin accounts for 85-95% of the whole modified resin adsorption tower by volume, and the residence time of the high-calcium high-fluorine high-salt concentrated water in the modified resin adsorption tower is 36-39 min.

6. A high calcium, high fluorine, high salt concentrated water zero discharge treatment system, characterized in that, Comprise: The dosing unit is used for pre-configuring a coagulant for removing fluorine and calcium and a modified resin according to the water quality characteristics of high-calcium high-fluorine high-salt concentrated water, the coagulant is compounded by polyaluminum chloride solution, aluminum chloride solution, polyaluminum sulfate solution, sodium carbonate solution and carboxymethyl cellulose, and the modified resin is prepared by styrene-diethyl styrene resin polymer, polyvinyl alcohol solution, polyacrylate resin, azobisisobutyronitrile, sodium hydroxide solution, chloroacetic acid, isopropyl alcohol and petroleum ether; The high-density sedimentation tank comprises a coagulation tank, a flocculation tank and a sedimentation tank connected in sequence, and is used for sequentially coagulating, flocculating and solid-liquid separating the high-calcium high-fluorine high-salt concentrated water; The dosing unit is used for adding the coagulant into the coagulation tank and adding polyacrylamide into the flocculation tank; The modified resin adsorption tower is used for adsorbing the supernatant after the solid-liquid separation of the high-calcium high-fluorine high-salt concentrated water in the sedimentation tank, and the modified resin adsorption tower is filled with the modified resin; The reverse osmosis membrane is used for reverse osmosis treatment of the water outlet of the modified resin adsorption tower; The evaporation crystallizer is used for evaporation crystallization of the concentrated water produced after the reverse osmosis treatment, and industrial sodium chloride products are obtained. The preparation method of the modified resin comprises: The styrene-diethyl styrene resin polymer with a crosslinking degree of 8-9% is selected; The polyvinyl alcohol solution with an alcoholysis degree of 79% is placed in a reaction kettle, 950-1040 mg of the styrene-diethyl styrene resin, 67-125 mg of the polyacrylate resin and 1.3-5.7 ml of the azobisisobutyronitrile are added into the polyvinyl alcohol solution per liter by volume; The reaction kettle is heated to 98℃, and stirred for 560-670 min at a stirring speed of 55-95 r / min; After the reaction is completed, the resin mixture is cooled and filtered, washed with 2% sodium hydroxide solution for 3-5 times, petroleum ether for 3-5 times, and clean water for 3-5 times, and vacuum dried at 65℃ for 110-130 min, and cooled; The resin mixture and the chloroacetic acid are placed in the reaction kettle at a mass ratio of 5-6:1, reacted in the reaction kettle at 45-49℃ for 160-180 min, and the isopropyl alcohol is added to terminate the reaction at a volume ratio of 10-15 ml / L, and the solid material is obtained after cooling and filtering; The solid material is washed with the petroleum ether for 3-5 times, clean water for 3-5 times, and the modified resin is obtained after vacuum drying at 60℃ for 3-4 h.

7. The high calcium, high fluorine, high salt concentrated water zero discharge treatment system according to claim 6, characterized in that, The preparation method of the coagulant comprises: The polyaluminum chloride solution is 21-27% by mass, the aluminum chloride solution is 3-11% by mass, the polyaluminum sulfate solution is 4-7% by mass, and the sodium carbonate solution is 13-19% by mass, and a mixed solution is formed in a volume ratio of 5-7:1:2:3-5; 0.01-0.05 g of the carboxymethyl cellulose is added per liter of the mixed solution, mechanical stirring is performed at a speed of 45-55 rpm for 35-67 min, and then ultrasonic treatment is performed for 3-7 min to obtain the coagulant.

8. The high calcium, high fluorine, high salt concentrated water zero discharge treatment system according to claim 6, characterized in that, The high-calcium high-fluorine high-salt concentrated water zero-discharge treatment system further comprises a first booster pump, a second booster pump, a third booster pump and a high-pressure pump, the first booster pump is used to send the high-calcium high-fluorine high-salt concentrated water into the high-density sedimentation tank, the second booster pump is used to send the supernatant after solid-liquid separation in the sedimentation tank into the modified resin adsorption tower, the high-pressure pump is used to send the high-calcium high-fluorine high-salt concentrated water after treatment in the modified resin adsorption tower into the reverse osmosis membrane, and the third booster pump is used to send the concentrated water produced after reverse osmosis treatment into the evaporation crystallizer.

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