Treatment device and treatment method for mine water

Abstract

The application belongs to the technical field of water treatment, and provides a mine water treatment device and method. The treatment device comprises a cyclone device, a first fluidized crystallization device, a sedimentation and filtration device, a decarbonization device, a nanofiltration assembly, a reverse osmosis device and a second fluidized crystallization device. The cyclone device, the first fluidized crystallization device, the sedimentation and filtration device and the decarbonization device are matched to effectively remove hardness from mine water, and not only have a small footprint, but also the carbon dioxide generated by the decarbonization device is reused to reduce the amount of reagent. In addition, through the cooperation of the nanofiltration assembly, the reverse osmosis device and the second fluidized crystallization device, the mine water is recycled, and the problem of high energy consumption of the evaporation crystallization technology is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a mine water treatment device and method. BACKGROUND

[0002] Mine water refers to all water filled into underground mining space during coal mining, which is groundwater polluted during coal mining. Most of the mine water is high salinity mine water, and the total dissolved solids (TDS) mass concentration is greater than or equal to 1000 mg / L. After simple treatment, it cannot be used. At the same time, due to the lack of receiving water body, mine water discharge will cause soil erosion, salinization, vegetation wilting, etc. of surface water, which limits the discharge of mine water.

[0003] In the traditional technology, the mine water zero discharge process mainly uses pretreatment + membrane concentration / membrane separation + evaporation crystallization process, but the pretreatment has the problems of large amount of chemicals and high operation cost, and most of the zero discharge uses evaporation crystallization process which consumes a large amount of steam and electricity. Therefore, how to reduce the cost of pretreatment chemicals and realize zero discharge without evaporation is an urgent problem to be solved. SUMMARY

[0004] Based on this, an embodiment of the present application provides a mine water treatment device and method with zero discharge, no evaporation and low chemical cost.

[0005] In a first aspect, the present application provides a mine water treatment device, which comprises:

[0006] A cyclone device is used to add a precipitant to the mine water and perform cyclone treatment to remove solid suspensions;

[0007] A first fluidized crystallization device is used to add seeds, alkaline substances and carbon dioxide to the effluent of the cyclone device, and to discharge sludge containing calcium carbonate crystals and primary treated mine water, respectively;

[0008] A sedimentation and filtration device is used to perform sedimentation and filtration treatment on the primary treated mine water, and to discharge primary concentrated water and primary produced water, respectively;

[0009] A decarbonization device is used to adjust the pH of the primary concentrated water to be acidic and to perform stripping on the primary concentrated water, and to discharge carbon dioxide and secondary concentrated water, respectively, wherein the carbon dioxide is introduced into the fluidized crystallization device through a first pipeline;

[0010] A nanofiltration assembly comprises a first nanofiltration device and a second nanofiltration device, wherein the first nanofiltration device is used to perform nanofiltration on the secondary concentrated water, and to discharge tertiary concentrated water and secondary produced water, respectively; and the second nanofiltration device is used to perform nanofiltration on the secondary produced water, and to discharge quaternary concentrated water and tertiary produced water, respectively;

[0011] a reverse osmosis device for reverse osmosis treatment of the third-stage concentrated water, and discharging reclaimed water and salt-making water, respectively; and

[0012] a second fluidized crystallization device for adding calcium chloride to the third-stage concentrated water to form gypsum.

[0013] In some embodiments, the precipitation and filtration device comprises, in sequence along a mine water treatment direction, a fluidized bed solid-liquid separator, an air floatation device, an ultrafilter, an ion resin filter, and a first reverse osmosis device, and the first-stage concentrated water and the first-stage produced water are discharged by the first reverse osmosis device.

[0014] In some embodiments, an activated carbon adsorption device is further arranged between the first-stage nanofiltration device and the second-stage nanofiltration device, and the activated carbon adsorption device is used for removing organic pollutants in the second-stage produced water.

[0015] In some embodiments, the fourth-stage concentrated water produced by the second-stage nanofiltration device is introduced into the decarbonization device through a second pipeline.

[0016] In some embodiments, the produced water of the second fluidized crystallization device is introduced into the first fluidized crystallization device through a third pipeline.

[0017] In some embodiments, the reverse osmosis device comprises, in sequence along a treatment direction of the third-stage produced water, a second reverse osmosis device and a third reverse osmosis device.

[0018] In some embodiments, the concentrated water produced by the second reverse osmosis device is salt-making water.

[0019] In some embodiments, the produced water of the third reverse osmosis device is reclaimed water, and the first-stage produced water discharged by the first reverse osmosis device is introduced into the third reverse osmosis device through a fourth pipeline for reverse osmosis treatment.

[0020] In some embodiments, the mine water treatment device further comprises a dewatering device, and the dewatering device comprises a sludge filter press and a gypsum dewatering device.

[0021] The sludge filter press is used for dewatering treatment of sludge produced by the first fluidized crystallization device and sludge produced by the second fluidized crystallization device.

[0022] The gypsum dewatering device is used for dewatering treatment of gypsum produced by the second fluidized crystallization device.

[0023] In some embodiments, the mine water treatment device further comprises an oxidation device, and the oxidation device is arranged on a water outlet side of the precipitation and filtration device, and the oxidation device is used for oxidizing and removing organic pollutants in the first-stage concentrated water.

[0024] In a second aspect, the present application provides a method for treating mine water, the method comprising:

[0025] adding a precipitant to the mine water and performing a cyclone treatment to remove solid suspensions; then adding seeds, an alkaline substance and carbon dioxide to the mine water to perform a first fluidized crystallization treatment, forming sludge containing calcium carbonate crystals and first treated mine water;

[0026] performing a precipitation treatment and a filtration treatment on the first treated mine water to remove solid suspensions and colloids, obtaining first concentrated water and first produced water;

[0027] performing a decarbonization treatment on the first concentrated water, comprising: adjusting the pH of the first concentrated water to be acidic, and stripping the first concentrated water to produce carbon dioxide and second concentrated water, the carbon dioxide being transported to the first fluidized crystallization treatment;

[0028] performing a first nanofiltration treatment on the second concentrated water to produce third concentrated water and second produced water, adding calcium chloride to the third concentrated water and performing a second fluidized crystallization treatment to form gypsum;

[0029] performing a second nanofiltration treatment on the second produced water to produce fourth concentrated water and third produced water;

[0030] performing a reverse osmosis treatment on the third produced water to obtain recycled water and salt water.

[0031] In some embodiments, the fourth concentrated water is mixed with the first concentrated water to perform the decarbonization treatment.

[0032] In some embodiments, the second nanofiltration treatment is preceded by an activated carbon removal of organic pollutants treatment on the second produced water.

[0033] In some embodiments, the water produced by the second fluidized crystallization treatment is mixed into the effluent of the cyclone treatment to perform the first fluidized crystallization treatment.

[0034] In some embodiments, the reverse osmosis treatment comprises a second reverse osmosis treatment and a third reverse osmosis treatment, the concentrated water of the second reverse osmosis treatment being salt water, and the produced water of the third reverse osmosis treatment being recycled water.

[0035] In some embodiments, the precipitation treatment and the filtration treatment comprise, in sequence, fluidized bed solid-liquid separation, air flotation, ultrafiltration, ion resin filtration and a first reverse osmosis treatment.

[0036] In some embodiments, the first reverse osmosis treatment produces the first concentrated water and the first produced water, and the first produced water is mixed with the produced water of the second reverse osmosis treatment to perform the third reverse osmosis treatment.

[0037] Compared with the conventional technology, the present application has at least the following beneficial effects:

[0038] The present application adopts the combination of the cyclone device, the first fluidized crystallization device and the sedimentation filtration device to pretreat the mine water, which can effectively reduce the water hardness, and significantly reduce the cost compared with the high-efficiency sedimentation tank in the conventional technology. In addition, the first fluidized crystallization device uses the carbon dioxide generated by the decarbonization device to remove hardness, reduces the dosage of reagent, and forms solid calcium carbonate crystals that can be recycled. Furthermore, the combination of the decarbonization device, the primary nanofiltration device, the secondary nanofiltration device, the reverse osmosis device and the second fluidized crystallization device in the present application realizes the treatment of the concentrated water of the mine water, realizes the multi-stage reuse of water, including the use of the generated concentrated water as chlor-alkali industrial salt water, and the reuse of sludge as gypsum, avoiding the high energy consumption problem of the evaporation crystallization process in the conventional process. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The present application is provided for the schematic diagram of the mine water treatment device in an embodiment.

[0040] Among them, 10-cyclone device; 20-first fluidized crystallization device; 30-sedimentation filtration device; 31-fluidized bed solid-liquid separator; 32-air float; 33-ultrafilter; 34-ion resin filter; 35-first reverse osmosis device; 40-oxidation device; 50-decarbonization device; 60-nanofiltration assembly; 61-primary nanofiltration device; 62-activated carbon adsorption device; 63-secondary nanofiltration device; 70-reverse osmosis device; 71-second reverse osmosis device; 72-third reverse osmosis device; 80-second fluidized crystallization device; 90-dewatering device; 91-sludge filter press; 92-gypsum dewatering device. DETAILED DESCRIPTION

[0041] The present application will be further described in detail below in conjunction with the embodiments and examples. These embodiments and examples are only used to illustrate the present application and are not used to limit the scope of the present application. The purpose of providing these embodiments and examples is to make the disclosure of the present application more thorough and comprehensive. It should also be understood that the present application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various modifications or changes without departing from the spirit of the present application, and the equivalent forms obtained thereby also fall within the protection scope of the present application. In addition, in the following description, a large number of specific details are given in order to provide a more complete understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0042] 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 application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0043] In the present application, "optionally", "optional", "option" means optional, that is, selected from "have" or "no" two parallel schemes. If there are multiple "optional" in a technical solution, unless otherwise specified, and there is no contradiction or mutual restriction, each "optional" is independent.

[0044] In the present application, the terms "first", "second", etc. in the "first aspect", "second aspect" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or quantity, nor can it be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", etc. only serve the purpose of non-exhaustive enumeration description, and should be understood as not constituting a closed limitation on the quantity.

[0045] In the present application, the technical features described in an open manner include closed technical solutions consisting of listed features, and also include open technical solutions containing listed features.

[0046] In the present application, with respect to the numerical interval (i.e. numerical range), unless otherwise specified, the distribution of the optional values in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e. the minimum value and the maximum value) of the numerical interval, and every value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only points to the integers in the numerical interval, including the two endpoint integers of the numerical range and every integer between the two endpoints, it is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe a feature or characteristic, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. The "numerical interval" is allowed to be broadly defined as a quantitative interval, such as a percentage interval, a ratio interval, a ratio interval, etc.

[0047] All references to documents mentioned in this application are incorporated herein by reference as if each document were individually incorporated by reference. Unless they conflict with the inventive purpose and / or technical solution of this application, all cited documents are incorporated herein by reference in their entirety and for all purposes. When citing documents in this application, the definitions of relevant technical features, terms, nouns, phrases, etc., are also incorporated herein by reference. When citing documents in this application, examples and preferred embodiments of the cited technical features may also be incorporated herein by reference, but only to the extent that they enable the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or modifications shall be made adaptably to the description in this application.

[0048] In traditional technologies, the pretreatment stage of mine water hardening processes often employs high-efficiency sedimentation tanks, with the added reagents typically in the form of sodium carbonate + liquid alkali / lime. The large amount of civil engineering work required for these high-efficiency sedimentation tanks leads to high costs for zero-discharge projects. Furthermore, the end-of-pipe processes for zero-discharge mine water often involve evaporation and crystallization to produce sodium chloride / sodium sulfate crystals, commonly using MVR and multi-effect evaporation crystallization. Both of these processes consume large amounts of steam and electricity, resulting in high operating costs for zero-discharge mine water. This application, however, effectively reduces the hardness of mine water through a cyclone device, a first fluidized bed crystallization device, and a sedimentation filtration device. It also utilizes carbon dioxide generated from the decarbonation device in subsequent treatment processes as a reagent, reducing both civil engineering costs and the amount of sodium carbonate used, thus lowering pretreatment operating costs. Moreover, this application employs a decarbonation device, a first-stage nanofiltration device, a second-stage nanofiltration device, a reverse osmosis device, and a second fluidized bed crystallization device in the treatment of concentrated mine water. The treated water quality meets the requirements for reuse water and the brine requirements for the chlor-alkali industry, respectively. Furthermore, the sludge is treated to obtain gypsum, achieving zero-discharge mine water treatment without evaporation.

[0049] It should be noted that in this application, concentrated water refers to the output water after treatment with concentrated pollutants, while product water refers to the output water with partial removal of pollutants. Taking reverse osmosis as an example, after mine water is treated, the concentrate (with enriched pollutants) produced by reverse osmosis is called concentrated water, and the discharged clean water (with a lower concentration of pollutants than the concentrated water) is called product water.

[0050] The first aspect of this application provides a mine water treatment apparatus, such as... Figure 1 As shown, the mine water treatment device includes:

[0051] The cyclone device 10 is used to add a flocculant to mine water and perform cyclone treatment to remove suspended solids.

[0052] The first fluidized bed crystallization device 20 is used to add seed crystals, alkaline substances and carbon dioxide to the effluent of the cyclone device 10, and respectively discharge sludge containing calcium carbonate crystals and primary treated mine water.

[0053] A sedimentation and filtration device 30 is used to perform sedimentation and filtration treatment on the primary treated mine water, and discharge primary concentrated water and primary produced water, respectively;

[0054] A decarbonization device 50 is used to adjust the pH of the primary concentrated water to be acidic, and perform stripping on the primary concentrated water, and discharge carbon dioxide and secondary concentrated water, respectively, wherein the carbon dioxide is introduced into the fluidized crystallization device through a first pipeline;

[0055] A nanofiltration assembly 60 includes a primary nanofiltration device 61 and a secondary nanofiltration device 62, wherein the primary nanofiltration device 61 is used to perform nanofiltration on the secondary concentrated water, and discharge tertiary concentrated water and secondary produced water, respectively; and the secondary nanofiltration device 62 is used to perform nanofiltration on the secondary produced water, and discharge quaternary concentrated water and tertiary produced water, respectively;

[0056] A reverse osmosis device 70 is used to perform reverse osmosis treatment on the tertiary produced water, and discharge recycled water and salt water, respectively;

[0057] A second fluidized crystallization device 80 is used to add calcium chloride to the tertiary concentrated water to form gypsum.

[0058] The combination of the cyclone device 10, the first fluidized crystallization device 20 and the sedimentation and filtration device 30 is used to pretreat the mine water, which not only effectively reduces the water hardness, but also significantly reduces the cost compared with the high-efficiency sedimentation tank in the traditional technology. In addition, the first fluidized crystallization device 20 uses the carbon dioxide generated by the decarbonization device 50 to remove hardness, which reduces the amount of reagent and forms solid calcium carbonate crystals that can be recycled. Furthermore, the combination of the decarbonization device 50, the primary nanofiltration device 61, the secondary nanofiltration device 62, the reverse osmosis device 70 and the second fluidized crystallization device 80 in the present application realizes the treatment of the concentrated water of the mine water, realizes the multi-stage recycling of the water, including the use of the generated concentrated water as salt water in the chlor-alkali industry, and the recycling of the sludge as gypsum, which avoids the high energy consumption problem of the evaporation crystallization process in the traditional process.

[0059] In the present application, the mine water first enters the cyclone device 10, which is a device that organically integrates physical and chemical reactions, and integrates direct coagulation, critical flocculation, centrifugal separation and sludge densification technology. In a short time (25-30 minutes), the wastewater is rapidly and multi-staged purified in the same tank. The removal rate of solid suspended matter is as high as 99%, and the removal rate of organic pollutants carried by the coal slurry in the mine water can reach 40%-70%. In cooperation with the first fluidized crystallization device 20, the crystallization effect of the first fluidized crystallization device 20 for hardness removal can be effectively guaranteed.

[0060] Optionally, the precipitant in the cyclone device 10 comprises polyaluminum chloride (PAC) and polyacrylamide (PAM); further optionally, the dosage of PAC in the mine water is 20 mg / L-40 mg / L; and the dosage of PAM is 0.5 mg / L-1.5 mg / L.

[0061] In the present application, the first fluidized crystallization device 20 generates calcium carbonate crystals from calcium ions in the mine water by adding seed crystals, liquid alkali and carbon dioxide, and the generated calcium carbonate crystals directly adhere to the surface of the seed crystals to grow, eventually forming calcium carbonate crystals with an average diameter of 1 mm-3 mm, effectively reducing the hardness of the mine water. Compared with the production of calcium carbonate precipitate from calcium ions in the high-efficiency sedimentation tank, the calcium carbonate crystals formed in the present application can be recycled. In addition, the upward flow rate of the first fluidized crystallization device 20 can reach 60 m / h-100 m / h, so a single set of crystallization granulation device has a large processing capacity and can replace the high-efficiency sedimentation tank, thereby saving a large amount of civil engineering cost, and the generated carbon dioxide in the subsequent decarbonization device 50 can be recovered, thereby reducing the cost of hardness removal reagents, and the calcium ions in the treated water can reach below 20 mg / L.

[0062] Optionally, the alkaline substance comprises at least one of a lye and sodium carbonate.

[0063] Optionally, activated carbon is further added to the first fluidized crystallization device 20. The activated carbon can remove part of the organic pollutants in the mine water after being added.

[0064] Optionally, the pH in the first fluidized crystallization device 20 is ≥10, preferably 11.5.

[0065] In the present application, the decarbonization device 50 acidifies the primary concentrated water to remove carbon dioxide in the process of aeration stripping and reduce alkalinity.

[0066] Optionally, the pH in the decarbonization device 50 is ≤5, preferably 4.2. Further optionally, the acidifying agent used in the acidification process comprises sulfuric acid.

[0067] In the present application, the concentrated water treated by the primary nanofiltration is treated by the second fluidized crystallization device 80, and calcium chloride is added to remove sulfate radicals in the concentrated water, and the formed sludge mainly comprises gypsum. Further, the sludge is subjected to dewatering treatment, and the water content of the gypsum is ≤55%.

[0068] In some embodiments, the precipitation filtration device 30 comprises, in sequence along the mine water treatment direction, a fluidized bed solid-liquid separator 31, an air floatation device 32, an ultrafilter 33, an ion resin filter 34 and a first reverse osmosis device 35, and the primary concentrated water and the primary produced water are discharged from the first reverse osmosis device 35.

[0069] The fluidized bed solid-liquid separation device in the application can change the random growth mode of the flocculation particles, increase the particle size of the flocculation particles, and thus form a dense flocculation body. Further, by controlling the coagulation chemical conditions and the fluid dynamics conditions of the fluidized bed, and by ensuring the stability of the fluidized bed in the granulation zone of the equipment through the particle circulation system, the process system can be continuously, efficiently and stably operated. The moisture content of the separated sludge can reach 80% to 85% (for a system mainly containing inorganic suspended particles) or 90% to 95% (for a system containing organic components and inorganic suspended particles).

[0070] Optionally, the effluent turbidity of the fluidized bed solid-liquid separation device is ≤3 NTU, and the flow rate is 60 m / h to 100 m / h.

[0071] Optionally, a precipitating agent is added to the fluidized bed solid-liquid separation device.

[0072] In the application, the dissolved oil stains and the light and small particles that are difficult to settle are removed by adding coagulants and flocculants in the air floatation device 32, so as to avoid the pollution of the subsequent ultrafiltration and nanofiltration membranes. Optionally, the scum generated by the air floatation device 32 can be separated and treated as sludge.

[0073] In the application, the ultrafiltration device 33 is used to remove the residual solid suspended particles and colloids in the mine water, and the effluent turbidity of the ultrafiltration device 33 is ≤1 NTU.

[0074] In the application, the ion resin filter 34 can remove the residual hardness in the mine water, so as to avoid the scaling problem of the subsequent membrane device. Optionally, the ion resin filter 34 can be washed and regenerated, and the regenerated liquid can be returned to the first fluidized crystallization device 20.

[0075] In the application, the salt content in the concentrated water discharged from the first reverse osmosis device 35 can reach 40,000 mg / L to 60,000 mg / L.

[0076] In some embodiments, an activated carbon adsorption device 62 is further arranged between the primary nanofiltration device 61 and the secondary nanofiltration device 62, and the activated carbon adsorption device 62 is used to remove the organic pollutants in the secondary produced water.

[0077] In the application, the activated carbon adsorption device 62 is further arranged to remove the organic pollutants and sulfate radicals, so as to meet the requirements of the subsequent salt water and recycled water.

[0078] In some embodiments, the fourth concentrated water generated by the secondary nanofiltration device 62 is introduced into the decarbonization device 50 through a second pipeline.

[0079] In some embodiments, the produced water of the second fluidized crystallization device 80 is introduced into the first fluidized crystallization device 20 through a third pipeline.

[0080] In some embodiments, the reverse osmosis device 70 comprises a second reverse osmosis device 71 and a third reverse osmosis device 72 arranged in sequence along the direction of the tertiary water production treatment. Optionally, the second reverse osmosis device 71 adopts a disc tube reverse osmosis membrane (DTRO).

[0081] In some embodiments, the concentrated water produced by the second reverse osmosis device 71 is salted water.

[0082] The second reverse osmosis device 71 in the present application further concentrates the fourth concentrated water, so that the salt content of the output salted water is 80000 mg / L-100000 mg / L, thereby reducing the water output and facilitating pipeline transportation to a chlor-alkali plant. The present application further processes the produced water through the third reverse osmosis device 72, effectively meeting the recycling requirements.

[0083] In some embodiments, the produced water of the third reverse osmosis device 72 is recycled water, and the first-stage produced water discharged by the first reverse osmosis device 35 is connected to the third reverse osmosis device 72 through a fourth pipeline for reverse osmosis treatment.

[0084] In some embodiments, the mine water treatment device further comprises a dewatering device 90; the dewatering device 90 comprises a sludge filter press 91 and a gypsum dewatering device 92.

[0085] The sludge filter press 91 is used for dewatering the sludge produced by the first fluidized crystallization device 20 and the sludge produced by the second fluidized crystallization device 80.

[0086] The gypsum dewatering device 92 is used for dewatering the gypsum produced by the second fluidized crystallization device 80.

[0087] In some embodiments, the mine water treatment device further comprises an oxidation device 40, which is arranged on the outlet side of the sedimentation and filtration device 30, and is used for oxidizing and removing organic pollutants in the first-stage concentrated water.

[0088] In some embodiments, the oxidation treatment adopts ozone oxidation treatment. Ozone produces highly active hydroxyl radicals in water, which further decompose and remove organic matter in mine water. The removal rate of organic pollutants can reach 20%-40%.

[0089] The second aspect of the present application provides a mine water treatment method, which comprises:

[0090] S1, adding a precipitating agent to the mine water and performing a cyclone treatment to remove solid suspensions; then adding seed crystals, an alkaline substance and carbon dioxide to the mine water to perform a first fluidized crystallization treatment, thereby forming sludge containing calcium carbonate crystals and first-stage treated mine water.

[0091] S2, performing a precipitation treatment and a filtration treatment on the primary treatment mine water to remove solid suspended matters and colloids, to obtain a primary concentrated water and a primary produced water.

[0092] S3, performing a decarbonization treatment on the primary concentrated water, including: adjusting a pH of the primary concentrated water to be acidic, and performing a stripping on the primary concentrated water to produce carbon dioxide and a secondary concentrated water, the carbon dioxide being transported to the first fluidized crystallization treatment.

[0093] S4, performing a primary nanofiltration treatment on the secondary concentrated water to produce a tertiary concentrated water and a secondary produced water, adding calcium chloride to the tertiary concentrated water and performing a second fluidized crystallization treatment to form gypsum.

[0094] S5, performing a secondary nanofiltration treatment on the secondary produced water to produce a quaternary concentrated water and a tertiary produced water.

[0095] S6, performing a reverse osmosis treatment on the tertiary produced water to obtain a reuse water and a salt water.

[0096] In some embodiments, the quaternary concentrated water is mixed with the primary concentrated water to perform the decarbonization treatment.

[0097] In some embodiments, before the secondary nanofiltration treatment, the secondary produced water is further treated by an activated carbon to remove organic pollutants.

[0098] In some embodiments, a produced water of the second fluidized crystallization treatment is mixed into an effluent of the cyclone treatment to perform the first fluidized crystallization treatment.

[0099] In some embodiments, the reverse osmosis treatment includes a second reverse osmosis treatment and a third reverse osmosis treatment, a concentrated water of the second reverse osmosis treatment being the salt water, and a produced water of the third reverse osmosis treatment being the reuse water.

[0100] In some embodiments, the precipitation treatment and the filtration treatment include sequentially performing a fluidized bed solid-liquid separation, a flotation, an ultrafiltration, an ion resin filtration, and a first reverse osmosis treatment.

[0101] In some embodiments, the first reverse osmosis treatment produces the primary concentrated water and the primary produced water, and the primary produced water is mixed with a produced water of the second reverse osmosis treatment to perform the third reverse osmosis treatment.

[0102] The embodiments of the present application will be described in detail below with examples. It should be understood that these examples are only used to illustrate but not to limit the scope of the present application. The experimental methods in the following examples without specific conditions are preferred to refer to the guidance given in the present application, and can also be carried out according to the experimental manual or conventional conditions in the art, or according to the conditions suggested by the manufacturer, or according to the experimental methods known in the art. Among them, the test method of water quality in examples and comparative examples meets the "Water and Wastewater Monitoring and Analysis Methods" (fourth edition).

[0103] The solid suspended substance (SS) of the mine water is 500 mg / L, the total hardness is 1200 mg / L, the oil content is 5 mg / L, the COD is 20 mg / L, the chloride ion content is 200 mg / L, the sulfate radical content is 4000 mg / L, and the silicon dioxide content is 5 mg / L.

[0104] Example 1

[0105] The mine water enters the cyclone device 10, a precipitant is added in the cyclone device 10 and the cyclone treatment is carried out to remove the solid suspended substance, the precipitant includes PAC and PAM, the addition amount of PAM in the mine water is 30 mg / L; the addition amount of PAM is 1 mg / L.

[0106] The effluent of the cyclone device 10 enters the first fluidized crystallization device 20, the seed crystal, sodium carbonate and carbon dioxide are added to the effluent of the cyclone device 10, the addition amount of sodium carbonate is 750 mg / L, the input amount of carbon dioxide is 250 mg / L, the addition amount of seed crystal is 50 mg / L, and the sludge containing calcium carbonate crystal and the first-stage mine water are discharged respectively.

[0107] The first-stage mine water enters the fluidized bed solid-liquid separator 31, the air floatation device 32, the ultrafilter 33, the ion resin filter 34 and the first reverse osmosis device 35 in sequence to carry out the precipitation treatment and the filtration treatment, and the first-stage concentrated water and the first-stage product water are discharged from the first reverse osmosis device 35 respectively.

[0108] The first-stage concentrated water first enters the oxidation device 40 to carry out the ozone oxidation treatment, and then enters the decarburization device 50 to adjust the pH of the first-stage concentrated water to be acidic and to carry out the stripping of the first-stage concentrated water, and the carbon dioxide and the second-stage concentrated water are discharged respectively, and the carbon dioxide is input into the fluidized crystallization device through the first pipeline.

[0109] The second-stage concentrated water enters the first nanofiltration device 61 to carry out the nanofiltration, and the third-stage concentrated water and the second-stage product water are discharged respectively; the second-stage product water first enters the activated carbon adsorption device 62 to remove the organic pollutants, and then enters the second nanofiltration device 62 to carry out the nanofiltration, and the fourth-stage concentrated water and the third-stage product water are discharged respectively, and the fourth-stage concentrated water is backflowed into the decarburization device 50 through the second pipeline.

[0110] The third-stage water production enters the second reverse osmosis device 71 and the third reverse osmosis device 72 in turn, wherein the concentrated water produced by the second reverse osmosis device 71 is salted water, the TDS of the salted water is 60000 mg / L-80000 mg / L, the TOC is less than or equal to 10 mg / L, and the sulfate is less than or equal to 50 mg / L; the first-stage water production discharged by the first reverse osmosis device 35 is also connected to the third reverse osmosis device 72 through the fourth pipeline for reverse osmosis treatment, and the water production of the third reverse osmosis device 72 is reuse water, the TDS of the reuse water is less than or equal to 200 mg / L, the COD is less than or equal to 20 mg / L, and the chloride ion is less than or equal to 50 mg / L.

[0111] The third-stage concentrated water enters the second fluidized crystallization device 80 and calcium chloride is added to form gypsum, and the water production (i.e., supernatant) in the second fluidized crystallization device 80 is backflowed to the first fluidized crystallization device 20 through the third pipeline for treatment.

[0112] The sludge produced by the first fluidized crystallization device 20 and the sludge produced by the second fluidized crystallization device 80 enter the sludge filter press 91 for dewatering treatment; and the gypsum produced by the second fluidized crystallization device 80 enters the gypsum dewatering device 90 for dewatering treatment.

[0113] Through the above embodiments, the combination of the cyclone device 10, the first fluidized crystallization device 20 and the sedimentation and filtration device 30 is adopted to pretreat the mine water, which not only can effectively reduce the water hardness, but also significantly reduces the cost compared with the high-efficiency sedimentation tank in the traditional technology; in addition, the first fluidized crystallization device 20 uses the carbon dioxide produced by the decarbonization device 50 to remove hardness, which reduces the dosage of reagents and forms solid calcium carbonate crystals that can be recycled. Furthermore, the combination of the decarbonization device 50, the first-stage nanofiltration device 61, the second-stage nanofiltration device 62, the reverse osmosis device 70 and the second fluidized crystallization device 80 is adopted to treat the concentrated water of the mine water, which realizes multi-stage reuse of water, including that the produced concentrated water is used as salted water in the chlor-alkali industry, and the sludge is reused and treated as gypsum, thereby avoiding the high energy consumption problem of the evaporation crystallization process in the traditional process.

[0114] Any combination of the technical features of the above-described embodiments can be made, and in order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combination of the technical features does not exist, it should be considered as the scope of the present disclosure.

[0115] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific manner, but should not be construed as limiting the scope of the patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method of treating mine water, characterised in that, The mine water treatment method comprises: adding a precipitant to the mine water and performing cyclone treatment to remove solid suspensions; then adding seeds, an alkaline substance and carbon dioxide to the mine water to perform first fluidized crystallization treatment, forming sludge containing calcium carbonate crystals and first-stage treated mine water; performing sedimentation treatment and filtration treatment on the first-stage treated mine water, which comprises sequentially performing fluidized bed solid-liquid separation, air flotation, ultrafiltration, ion resin filtration and first reverse osmosis treatment to remove solid suspensions and colloids, obtaining first-stage concentrated water and first-stage produced water; performing decarburization treatment on the first-stage concentrated water, which comprises adjusting the pH of the first-stage concentrated water to be acidic and stripping the first-stage concentrated water to produce carbon dioxide and second-stage concentrated water, and the carbon dioxide is transported to the first fluidized crystallization treatment; performing first nanofiltration treatment on the second-stage concentrated water to produce third-stage concentrated water and second-stage produced water, adding calcium chloride to the third-stage concentrated water and performing second fluidized crystallization treatment to form gypsum, and the produced water of the second fluidized crystallization treatment is mixed into the effluent of the cyclone treatment to perform the first fluidized crystallization treatment; performing activated carbon organic pollutant removal treatment on the second-stage produced water, and then performing second nanofiltration treatment on the second-stage produced water to produce fourth-stage concentrated water and third-stage produced water, and the fourth-stage concentrated water is mixed with the first-stage concentrated water to perform the decarburization treatment; performing reverse osmosis treatment on the third-stage produced water, which comprises second reverse osmosis treatment and third reverse osmosis treatment, the concentrated water of the second reverse osmosis treatment is salted water, the first-stage produced water is mixed with the produced water of the second reverse osmosis treatment to perform the third reverse osmosis treatment, and the produced water of the third reverse osmosis treatment is recycled water.

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