WO2022100313A1 - Mine water advanced treatment system and mine water treatment method thereof - Google Patents

Abstract

Disclosed in the present invention are a mine water advanced treatment system and a treatment method thereof. The system comprises a regulating tank, a V-shaped filter tank, an ultrafiltration system, a primary reverse osmosis system, a secondary microfiltration softening system, a secondary reverse osmosis system, a tertiary microfiltration softening system, an ion exchange softening system, a DTRO system, and an evaporation crystallization salt separation system which are sequentially connected. Corresponding pre-treatment processes are performed according to different water inlet conditions, and the ultrafiltration system, the secondary microfiltration softening system, the tertiary microfiltration softening system, and a softening device are comprised. Clear liquid produced by the primary and secondary reverse osmosis systems, the DTRO system, and the evaporation crystallization salt separation system is mixed then to serve as produced water and discharged into a water production tank; and finally, concentrated water discharged from the DTRO system serves as concentrated salt water and enters the evaporation crystallization salt separation system to obtain industrial-grade anhydrous sodium sulfate and sodium chloride crystalline salt. The system and the method procedure of the present invention are simple, the produced water can be comprehensively utilized, the sodium sulfate and sodium chloride crystalline salt can be effectively separated, and thus resource utilization of crystalline salt separation is achieved.

Description

Mine water advanced treatment system and method for treating mine water technical field

The invention relates to a method and system for advanced treatment of mine water, belonging to the technical field of environmental protection water treatment.

Background technique

With the rapid development of the industry and the continuous increase in the demand for coal resources, the coal industry has made great progress, making the related industries also improved and progressed. However, a large amount of mine water emerges during coal mining, and the outflow of mine water far exceeds the coal mine's own water consumption. In the actual process of coal mining, the groundwater is in contact with coal seams and rock formations, as well as the influence of human activities, and a series of physical and chemical biochemical reactions are prone to occur, so it has significant characteristics of the coal industry. It is mainly reflected in that the content of suspended solids in mine water containing suspended solids is much higher than that of surface water, and the sensory properties are poor; at the same time, the suspended solids contained in the suspended solids have small particle size, light specific gravity, slow settling speed and poor coagulation effect; The ion content is much higher than that of general surface water, and the main ion components are sulfate ions and chloride ions, a large part of which are sulfate ions; mine water is often accompanied by a large amount of ferrous ions and manganese ions, which increases the processing efficiency difficulty. If this type of wastewater is directly discharged, it will not only waste water resources, but also easily cause environmental pollution, which will seriously affect the physical and mental health of human beings and the construction of an environment-friendly society.

Mine water, as high-salinity wastewater, has the characteristics of low COD and ammonia nitrogen content, high salinity, high suspended solids and TDS content, and large water production. This type of wastewater should be comprehensively utilized after advanced treatment to realize the recycling of water resources and the resource utilization of crystalline salt. As an energy-saving and environmentally friendly technology, membrane separation technology can separate substances at the molecular level. The separation process is a typical physical separation, with extremely low energy consumption, high degree of automation, simple process and convenient operation. Therefore, according to the quality conditions of mine water, the use of membrane separation technology can produce clean water that meets the requirements of effluent quality through step-by-step treatment. Produced water and clean water are recycled as water resources. The main component of concentrated mine water as concentrated brine is mixed salt of sodium sulfate and sodium chloride, and the content of sodium sulfate accounts for the main part. After further treatment, crystalline salt can be treated as a resource.

At present, the conventional treatment process for the discharge of concentrated brine that meets the standard is evaporation crystallization technology, which mainly includes single-effect evaporation, multi-effect evaporation and MVR evaporation. The concentrated brine produced by the treatment of mine water through membrane separation technology, in which inorganic salts exist in the form of miscellaneous salts. If the crystalline salts produced by the above evaporation crystallization process are miscellaneous salts, in general, such crystalline salts can be regarded as dangerous solids waste, which is not conducive to the resource utilization of crystalline salt. If not handled properly, this kind of crystalline salt will form secondary pollution under the action of leaching. From the perspective of crystallization technology, the crystallization technology of single-component salts is relatively mature. However, the solubility data and rate constants of single-component salts are not suitable for complex systems of mixed salts, even if the amount of other salts in the mixed salt is small. It may also have a great impact on the crystallization process, and it is difficult to ensure that the brine treatment meets the discharge requirements. Therefore, in view of the existing problems and deficiencies of the current treatment technology, the high-efficiency, energy-saving, and strong operability advanced mine water treatment process proposed in the patent application is hereby developed to realize the recovery and utilization of mine water resources and the treatment of salt-separated resources.

SUMMARY OF THE INVENTION

In order to solve the above problems, the purpose of the present invention is to propose a method and system for advanced treatment of mine water. The main process is "membrane separation technology + evaporation crystallization salt separation technology". The treatment process has the characteristics of strong operability, simple process, high safety factor, low equipment investment and operation cost, clean and pollution-free. Through advanced mine water treatment technology, pollutants such as hardness, colloidal particles, sulfate ions, chloride ions and other pollutants in the water are removed, and the effluent quality meets the three types of water quality in Table 1 of "Surface Water Environmental Quality Standard GB3838-2002" (non-lake, reservoir) and table water. 2. Water quality index requirements, at the same time, TDS is less than 500mg/L, sulfate is less than 250mg/L, so as to realize the recycling of water resources. At the same time, in the evaporative crystallization and salt separation system, it innovatively proposed "evaporative crystallization technology + freezing crystallization technology + single-effect evaporation technology" to achieve the purpose of salt separation of sodium sulfate and sodium chloride in mine water, which not only solved the problem of mixed salt and hazardous waste, but also Moreover, the crystalline salt can also be utilized as a resource. The salt-separation combined process has low energy consumption, simple operation, and the evaporation, crystallization, and salt-separation process of the binary system of sodium chloride and sodium sulfate does not require precise control, thereby reducing the operation cost.

In order to solve the above-mentioned problems, the scheme adopted in the present invention is as follows: a mine water advanced treatment system, which is characterized in that it includes a regulating tank, a V-type filter tank, an ultrafiltration system, a primary reverse osmosis system, and a secondary microfiltration system connected in sequence. Softening system, secondary reverse osmosis system, tertiary microfiltration softening system, ion exchange softening system, DTRO system and evaporative crystallization salt separation system; the primary reverse osmosis system, secondary reverse osmosis system, DTRO system and evaporative crystallization system The salt system is equipped with a clear liquid pipe to communicate with the production tank, which is used to discharge the clear liquid into the production tank.

Further, according to the mine water advanced treatment system according to the above design scheme, it is characterized in that the two-stage microfiltration softening system and the three-stage microfiltration softening system include a softening pool and a microfiltration membrane unit; Add soda ash and liquid caustic soda to remove calcium, magnesium and silicon; the microfiltration membrane unit adopts tubular microfiltration membrane, after the secondary microfiltration softening system and the third microfiltration softening system, the calcium ion concentration is lower than 15mg/L, The concentration is lower than 20mg/L, and the silica concentration is lower than 20mg/L.

Further, the mine water advanced treatment system according to the above design scheme is characterized in that, the water produced by the two-stage microfiltration softening system and the third-stage microfiltration softening system is provided with a pretreatment water production tank, and acid is added in the tank to adjust the pH to 6-9. , stripping to remove alkalinity.

Further, the mine water advanced treatment system according to the above design scheme is characterized in that, the evaporative crystallization and salt separation system includes an evaporative crystallization unit, a frozen crystallization unit, and a single-effect evaporative crystallization unit; the evaporative crystallization unit adopts MVR or multi-effect evaporation, The evaporative crystallization unit and the freezing crystallization unit are combined to obtain anhydrous sodium sulfate crystalline salt with a purity of ≥97%; the mother liquor produced by the freezing crystallization unit enters the single-effect evaporative crystallization unit; the single-effect evaporative crystallization unit adopts MVR or vacuum distillation to obtain chlorine The sodium chloride crystalline salt, with a purity of ≥97.5%, realizes the salt separation treatment of sodium sulfate and sodium chloride; the evaporative condensate discharged from the single-effect evaporative crystallization unit is used to preheat the liquid discharged from the freezing crystallizer.

Further, according to the mine water advanced treatment system according to the above-mentioned design scheme, it is characterized in that a waste water collection tank, a high-efficiency clarifier and a sludge concentration tank are arranged between the V-shaped filter tank and the adjustment tank; the waste water collection tank is arranged in the Below the V-type filter tank; the backwash wastewater of the V-type filter tank enters the wastewater collection tank through self-flow, and the effluent of the wastewater collection tank is connected to the high-efficiency clarifier; the supernatant of the high-efficiency clarifier enters the adjustment tank, and the lower sludge outlet is connected to the sludge thickening tank inlet. ; The supernatant of the sludge thickening tank is returned to the waste water collection tank, and the concentrated sludge enters the sludge treatment device.

Further, according to the mine water advanced treatment system according to the above-mentioned design scheme, it is characterized in that, the secondary microfiltration softening system and the tertiary microfiltration softening system are respectively provided with a concentrated water reaction tank and a concentrated water concentration tank; The inlet of the concentrated water reaction tank of the filtration softening system is connected to the concentrated water produced by the primary reverse osmosis system, and the outlet overflows to the concentrated water concentration tank of the secondary microfiltration softening system; the concentrated water reaction tank of the tertiary microfiltration softening system The inlet is connected to the concentrated water produced by the secondary reverse osmosis system, and the water outlet overflows to the concentrated water concentration tank of the third-stage microfiltration softening system; the second-stage microfiltration softening system reacts with the concentrated water of the third-stage microfiltration softening system Sodium carbonate and sodium hydroxide were added to the pool. The outlet overflows to the concentrated water concentration tank, and a stirring system is set in the tank, and the outlet is connected to the inlet of the second-stage microfiltration unit and the third-stage microfiltration unit.

Two-stage microfiltration softening system and three-stage microfiltration softening system include concentrated water reaction tank, concentrated water concentration tank and microfiltration membrane unit. The concentrated water reaction tank adopts chemical softening method, adding soda ash and liquid caustic soda for softening treatment; the microfiltration membrane unit adopts tubular microfiltration membrane, after the microfiltration softening system, the calcium ion concentration is lower than 15mg/L, and the magnesium ion concentration is lower than 20mg/L, the silica concentration is lower than 20mg/L.

The secondary reverse osmosis system and the ion exchange softener are provided with a pretreatment water tank, which is used for the pretreatment of the produced water of the secondary microfiltration softening system and the tertiary microfiltration softening system respectively, and acid is added to the pretreatment water tank to adjust the pH. To 6-9, strip to remove alkalinity.

Further, according to the method for treating mine water by the mine water advanced treatment system described in the above design scheme, it is characterized in that, after the mine water is regulated and homogenized by the adjustment tank, it enters the V-type filter tank for filtration, and the filtrate is used as purified water, and then passes through the Ultrafiltration system, primary reverse osmosis system, secondary microfiltration softening system, secondary reverse osmosis system, tertiary microfiltration softening system, ion exchange softening system, DTRO system and evaporative crystallization salt separation system; the primary reverse osmosis system The clear liquid produced by the system, the secondary reverse osmosis system and the DTRO system is mixed as produced water and discharged into the production pool; the concentrated water produced by the primary reverse osmosis system passes through the secondary microfiltration softening system and enters the secondary reverse osmosis system. Osmosis system; the concentrated water produced by the two-stage reverse osmosis system sequentially passes through the three-stage microfiltration softening system, the ion exchange softening system, and the DTRO system. Finally, the concentrated water discharged from the DTRO system enters the evaporative crystallization and salt separation system as concentrated brine, and the output Evaporate condensate, anhydrous sodium sulfate crystalline salt and sodium chloride crystalline salt.

Further, according to the method for treating mine water in the mine water advanced treatment system according to the above-mentioned design scheme, it is characterized in that, the adjustment tank is an aeration adjustment tank, and through aeration pre-oxidation treatment, the reducing substances in the waste water are removed, and the reducing substances in the waste water are removed for homogenization. Quality adjustment to maintain the stability of the subsequent process.

Further, according to the method for the mine water advanced treatment system described in the above-mentioned design scheme, it is characterized in that, the V-shaped filter tank adopts quartz sand homogeneous filter material for removing colloid and SS in the water, and the effluent turbidity is less than or equal to 3NTU .

Further, according to the method for treating mine water in the mine water advanced treatment system according to the above design scheme, it is characterized in that, the ultrafiltration system adopts hollow fiber membrane elements to remove bacteria, viruses and colloidal particles in the form of cross-flow filtration, and the recovery rate is greater than or equal to 95%.

Further, according to the method for treating mine water in the mine water advanced treatment system according to the above-mentioned design scheme, it is characterized in that the first-stage reverse osmosis system adopts a roll-type membrane, the recovery rate is greater than or equal to 70%, and the clean water is discharged into the water production tank; The secondary reverse osmosis system adopts roll membrane, the recovery rate is not less than 80%, and the clean water is discharged into the production tank.

Further, according to the method for treating mine water in the mine water advanced treatment system according to the above design scheme, it is characterized in that, the ion exchange softener adopts chelating resin, adopts 3-4% hydrochloric acid solution and 4-5% sodium hydroxide solution Resin regeneration.

Further, according to the method for treating mine water by the mine water advanced treatment system described in the above design scheme, it is characterized in that the recovery rate of the DTRO system is 50-55%, the operating pressure is ≤ 120bar, and the concentrated water discharged from the DTRO system is used as evaporative crystallization and salt separation The mother liquor of the system, the clean water discharged from the DTRO system is discharged into the production tank.

The invention discloses a method for advanced treatment of mine water, comprising the following steps:

After the high mine water is regulated and homogenized by the regulating tank, it enters the V-type filter tank for filtration, and the filtrate is used as purified water, which is gradually reduced by the primary reverse osmosis system, the secondary reverse osmosis system and the DTRO system. Each stage of membrane system has undergone corresponding pretreatment procedures according to different influent conditions, including ultrafiltration system, secondary microfiltration softening system, tertiary microfiltration softening system and ion exchange softening system. The clear liquid produced by the primary and secondary reverse osmosis systems and the DTRO system is mixed as produced water and discharged into the production pool; finally, the concentrated water discharged from the DTRO system is used as concentrated brine and enters the evaporative crystallization and salt separation system to obtain industrial grade. Anhydrous sodium sulfate and sodium chloride crystalline salt.

As a further solution, the miscellaneous salt mother liquor produced by the evaporative crystallization unit can be used to heat the sodium sulfate decahydrate crystal slurry formed by freezing and crystallization to recover part of the heat.

The invention also discloses a mine water advanced treatment system, comprising a regulating tank, a V-shaped filter tank, an ultrafiltration system, a first-stage reverse osmosis system, a second-stage microfiltration softening system, a second-stage reverse osmosis system, and a third-stage microfiltration system connected in sequence. Filter softening system, DTRO system and evaporative crystallization salt separation system.

Among them, a waste water collection tank, a high-efficiency clarifier and a sludge concentration tank are arranged between the V-type filter tank and the adjustment tank. The wastewater collection tank is set under the V-type filter tank, the backwash wastewater of the V-type filter tank flows into the wastewater collection tank, the outlet water of the wastewater collection tank is connected to the high-efficiency clarifier, the supernatant of the high-efficiency clarifier enters the adjustment tank, and the lower sludge outlet is connected to the sludge. The inlet of the concentration tank is connected, the supernatant of the sludge concentration tank is connected to the waste water collection tank, and the concentrated sludge is discharged into the sludge treatment device.

The technical effects of the present invention are as follows: (1) Mine water is treated to meet the influent requirements of the membrane separation process by using the regulating tank and the V-type filter, and the stability of the subsequent concentration treatment is maintained, and the membrane separation technology and the evaporative crystallization salt separation technology are combined. Further separation and purification make the effluent of the mine water meet the requirements of the three types of water quality in Table 1 (non-lakes and reservoirs) and the water quality indicators in Table 2 of "Surface Water Environmental Quality Standard GB3838-2002".

(2) Microfiltration softening device and softening system can effectively remove calcium, magnesium and silicon from water, and the system is simple to operate, without the need to invest a lot of chemicals and equipment costs.

(3) The quality of the effluent after advanced treatment of mine water is good and the system runs stably.

(4) The sodium sulfate and sodium chloride in the evaporative crystallization and salt separation system have high salt purity, which solves the problem of mixed salt hazardous waste and the disadvantage of difficulty in evaporative crystallization and salt separation of the sodium sulfate and sodium chloride binary system.

(5) The overall process is simple and easy to implement, the safety factor is high, and the salt separation operation is easy to control, realizing the recycling of mine water resources and the resource utilization of crystalline salt.

Description of drawings

Fig. 1 is a kind of mine water advanced treatment process schematic diagram disclosed by the present invention;

Figure 2 is a schematic diagram of the process flow of the evaporative crystallization salt separation system disclosed in the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

The embodiment discloses a method for advanced treatment of mine water, comprising the following technical solutions:

After preliminary treatment, the mine water enters the adjustment tank for homogenization adjustment and maintains the stability of the subsequent process. Pre-oxidation through aeration removes reducing substances such as iron and manganese in the wastewater, and then enters the V-type filter to further remove colloid and SS, and reduce the turbidity of the effluent, and the turbidity of the effluent is less than or equal to 3NTU. The filter tank is made of quartz sand homogeneous filter material. After being screened, intercepted and adhered, the influent water quality requirements of the subsequent process are obtained. Among them, the V-type filter backwash wastewater flows to the wastewater collection tank, and the wastewater collection tank can be set under the V filter tank to facilitate the backwash wastewater to flow. The wastewater in the wastewater collection tank is sent to the high-efficiency clarifier by the lift pump, and reacted and precipitated by adding a flocculant. The supernatant is discharged into the conditioning tank; the sludge is discharged into the sludge thickening tank. After the sludge entering the sludge thickening tank is sedimented by gravity, the supernatant is returned to the V filter backwash wastewater collection tank, and the sludge enters the sludge treatment system.

The effluent from the V-type filter enters the purification tank and is fed as the ultrafiltration system. The ultrafiltration system uses hollow fiber membrane elements to remove bacteria, viruses and colloidal particles in the form of cross-flow filtration, and improves the recovery rate of the system through a circulating pump. The ultrafiltration water enters the ultrafiltration tank. Ultrafiltration is the pretreatment unit of the primary reverse osmosis system. The produced water directly enters the primary reverse osmosis system. The primary reverse osmosis system uses a rolled reverse osmosis membrane. The system slows down the scaling of membrane elements by adding scale inhibitors. The clean water flows to the production tank by itself, and the concentrated water is used as the next-level raw water for subsequent treatment. After the first-stage reverse osmosis concentrated water enters the second-stage microfiltration softening system, it is pressed into the concentrated water reaction tank by the lift pump, and soda ash and liquid caustic soda are added to the reaction tank. The adsorption of Mg(OH) ₂ reduces the concentration of _SiO2 , which is retained by the tubular microfiltration membrane. The pH is adjusted back to 6-9 by adding acid, and then enters the pretreatment water production tank, and is removed to remove alkalinity. The softened water in the pretreatment water tank is pressed into the secondary reverse osmosis system by the booster pump and the high pressure pump. Grade microfiltration softening system for softening. The composition and process of the three-stage microfiltration softening system are basically the same as those of the two-stage microfiltration softening system. In order to further remove the hardness of the water, an ion exchange softening system is set up in the effluent of the three-stage microfiltration softening system. The softening system adopts chelating resin. In the regeneration process, 3-4% hydrochloric acid solution and 4-5% sodium hydroxide solution are used. DTRO system. The influent water enters the DTRO membrane column through the high-pressure pump and the circulating pump, and the produced water is collected and sent to the water production tank by the pump; the concentrated water enters the concentrated water pipeline and part of it is connected to the inlet of the circulating pump, and part of it is extracted and collected as a concentrated solution as a concentrated brine It is sent to the evaporative crystallization salt separation system.

The evaporative crystallization salt separation system includes an evaporative crystallization unit, a frozen crystallization unit, and a single-effect evaporative crystallization unit. The concentrated brine from DTRO enters the evaporation and crystallization unit, which can use MVR or multi-effect evaporation. This unit produces water and sodium sulfate crystal slurry from the salt leg, and obtains the sodium sulfate crystal salt through subsequent centrifugal drying. The mixed salt mother liquor discharged from the evaporation unit enters the freezing and crystallization unit, and most of the sodium sulfate crystal slurry in the mixed salt is precipitated by freezing and crystallization, and returns to the evaporation unit. A heat exchange device can be used in the return line to conduct heat exchange between the mixed salt mother liquor and the sodium sulfate crystal slurry discharged from the frozen crystallization. After being processed by the freezing crystallization unit, the discharged mother liquor is mainly composed of sodium chloride and a very small amount of sodium sulfate. The mother liquor enters the single-effect evaporation and crystallization unit, and can be concentrated by MVR or vacuum distillation, and then centrifuged and dried to obtain sodium chloride crystalline salt.

The present invention will be further described in detail below with reference to specific embodiments.

Example 1

In the embodiment of the present invention, the schematic diagram of the advanced treatment process of mine water and the schematic diagram of the process flow of the evaporative crystallization and salt separation system are shown in FIG. 1 and FIG. 2 . The water quality conditions of the mine water from a mining area are shown in Table 1.

Table 1 Mine water effluent quality conditions in a mining area:

serial number	name	unit	Numerical value
1	flow	m3 /h	2000
2	pH		7.91
3	COD	mg/L	20
4	suspended matter		20
5	suspended solids	mm	0.3
6	NH4 +	mg/L	0.37
7	K +	mg/L	5.76
8	Na +	mg/L	709.5
9	Mg 2+	mg/L	34.15
10	Ca 2+	mg/L	233
11	HCO 3 -	mg/L	306.7

12	Cl -	mg/L	96.94
13	F -	mg/L	0.73
14	SO 4 2-	mg/L	1927
15	SiO2	mg/L	14.37
16	Mn	mg/L	0.29
17	TDS	mg/L	3330

.

Mine water goes through the adjustment tank, aeration pre-oxidation and homogenization adjustment, and then enters the V-type filter tank for filtration. The filter tank adopts quartz sand homogeneous filter material. Purifies the pool and feeds the water as an ultrafiltration system. The ultrafiltration system uses PVDF hollow fiber membrane elements to remove bacteria, viruses and colloidal particles in the form of cross-flow filtration. The system recovery rate is about 96%, and the operating pressure is 0.2MPa. The ultrafiltration water enters the ultrafiltration tank. Ultrafiltration is the pretreatment unit of the primary reverse osmosis system. The produced water directly enters the primary reverse osmosis system. The primary reverse osmosis system uses a roll reverse osmosis membrane. The system slows down the scaling of membrane elements by adding scale inhibitors. The recovery rate can reach 73%, the TDS of clean water is about 18mg/L, which flows to the production tank by itself, and the TDS of concentrated water is about 6500mg/L, which is used as the next-level raw water for subsequent treatment. After the first-stage reverse osmosis concentrated water enters the second-stage microfiltration softening system, it is pressed into the concentrated water reaction tank by the lifting pump, and soda ash and liquid caustic soda are added to the reaction tank, and are intercepted by the tubular microfiltration membrane. The calcium ion concentration in the effluent is about 12mg/L, The magnesium ion concentration is about 15mg/L, and the silica concentration is about 16mg/L. After adding sulfuric acid to adjust the pH to 6.8, it enters the pretreatment production tank, and is purged to remove alkalinity. The softened water in the pretreatment water tank is pressed into the secondary reverse osmosis system by the booster pump and the high pressure pump. L, self-flow to the production tank, the concentrated water TDS is about 27000mg/L, and it is softened by a three-stage microfiltration softening system. The composition and process of the three-stage microfiltration softening system are basically the same as those of the two-stage microfiltration softening system. In order to further remove the hardness in the water, an ion exchange softening system is installed in the effluent of the three-stage microfiltration softening system, and the softening system adopts chelating resin. The concentration is about 18mg/L. When the effluent does not meet the requirements, use 4% hydrochloric acid solution and 5% sodium hydroxide solution for regeneration. Produced water enters the DTRO system. The influent water enters the DTRO membrane column through the high-pressure pump and the circulating pump. The operating pressure is about 3.0MPa, the recovery rate is about 52%, and the TDS of the produced water is about 495mg/L. L, a part of the concentrated water pipeline is connected to the inlet of the circulating pump, and the other part is extracted and collected as concentrated liquid, and sent to the evaporation crystallization and salt separation system as concentrated brine.

The concentrated brine from DTRO enters the evaporative crystallization unit. The evaporative crystallization unit preferably adopts countercurrent three-effect evaporation. As shown in Figure 2, the sodium sulfate crystallization tank is controlled to be in the high temperature section. The first-effect evaporation temperature is about 90 °C, and the second-effect evaporation temperature is about 77°C, the three-effect evaporation temperature is 60°C, and the sodium sulfate crystal slurry is produced from the first-effect salt leg, and the sodium sulfate crystal salt with a purity of 98% can be obtained by subsequent centrifugal drying. The mixed salt mother liquor discharged from the evaporative crystallization unit enters the freezing crystallization unit, and most of the sodium sulfate crystal slurry in the mixed salt is precipitated through freezing crystallization, and returns to the evaporative crystallization unit. A heat exchange device can be used in the return pipeline to exchange heat treatment between the mixed salt mother liquor and the sodium sulfate crystal slurry discharged from the freezing and crystallization unit. After being processed by the freezing crystallization unit, the discharged mother liquor is mainly composed of sodium chloride and a very small amount of sodium sulfate. The mother liquor enters the single-effect evaporative crystallization unit, and adopts reduced pressure evaporative crystallization. The evaporation temperature is 60 ° C, and the purity is 98% after centrifugal drying. of sodium chloride crystalline salt. The TDS of the water produced by the evaporative salt separation system is about 28 mg/L, and it is discharged into the production pool.

After the mine water is treated by the present invention, the produced water is composed of a mixture of a primary reverse osmosis system, a secondary reverse osmosis system, a DTRO system and a three-effect evaporation condensate water, and the comprehensive TDS is lower than 500 mg/L, which meets the reuse standard of local industrial parks; The sodium sulfate with a purity of 98% and the crystalline salt of sodium chloride with a purity of 98% can be recycled as industrial salt products, which meet the requirements of water resource recycling and salt separation.

Regarding the embodiments of the present invention, as a person skilled in the art, unless otherwise specified and limited, the above-mentioned embodiments should be regarded as description, explanation and guidance of the processing technology involved in the present invention, and do not have a limiting meaning, More not limited to the above-mentioned embodiments. For those skilled in the art, without violating the protection scope of the claims of the present invention, according to specific project conditions, simple replacements, deformations, etc. made to the embodiments all fall within the protection scope of the present invention.

Claims (15)

1. A mine water advanced treatment system, which is characterized in that it includes a regulating tank, a V-shaped filter tank, an ultrafiltration system, a primary reverse osmosis system, a secondary microfiltration softening system, a secondary reverse osmosis system, and a tertiary microfiltration system. Filtration softening system, ion exchange softening system, DTRO system and evaporative crystallization salt separation system; the primary reverse osmosis system, secondary reverse osmosis system, DTRO system and evaporative crystallization salt separation system are all provided with clear liquid pipes to communicate with the production pool , which is used to discharge the supernatant into the production tank.
2. The mine water advanced treatment system according to claim 1, wherein the two-stage microfiltration softening system and the three-stage microfiltration softening system comprise a softening pool and a microfiltration membrane unit; the softening pool adopts a chemical softening method, and soda ash is added. With liquid caustic soda to remove calcium, magnesium and silicon; the microfiltration membrane unit adopts tubular microfiltration membrane, after the second-stage microfiltration softening system and the third-stage microfiltration softening system, the calcium ion concentration is lower than 15mg/L, and the magnesium ion concentration is low At 20mg/L, the silica concentration is lower than 20mg/L.
3. The mine water advanced treatment system according to claim 1, characterized in that, the water produced by the two-stage microfiltration softening system and the three-stage microfiltration softening system is provided with a pretreatment water production tank, and acid is added in the tank to adjust the pH to 6-9, and the water is blown. Remove alkalinity.
4. The mine water advanced treatment system according to claim 1, wherein the evaporative crystallization and salt separation system comprises an evaporative crystallization unit, a frozen crystallization unit, and a single-effect evaporative crystallization unit; the evaporative crystallization unit adopts MVR or multi-effect evaporation, and the After the concentrated brine of the DTRO system is processed by the evaporative crystallization unit, the discharged mixed salt mother liquor enters the freezing crystallization unit, and most of the sodium sulfate crystal slurry in the mixed salt mother liquor is precipitated through freezing crystallization, and the crystal slurry is returned to the evaporative crystallization unit, and the evaporative crystallization unit Combined treatment with the freezing crystallization unit to obtain anhydrous sodium sulfate crystalline salt, with a purity of ≥97%; the mother liquor produced by the freezing crystallization unit enters the single-effect evaporative crystallization unit; the single-effect evaporative crystallization unit adopts MVR or vacuum distillation to obtain sodium chloride crystals Salt, with a purity of ≥97.5%, realizes the salt separation treatment of sodium sulfate and sodium chloride; the evaporative condensate produced by the single-effect evaporative crystallization unit shown in the figure enters the water production tank through the clear liquid pipe.
5. The mine water advanced treatment system according to claim 1, wherein a waste water collection tank, a high-efficiency clarification tank and a sludge concentration tank are arranged between the V-shaped filter tank and the adjustment tank; the waste water collection tank is arranged in the V-shaped Below the filter tank; the backwash wastewater from the V-type filter enters the wastewater collection tank through self-flow, and the effluent of the wastewater collection tank is connected to the high-efficiency clarifier; the supernatant of the high-efficiency clarifier enters the adjustment tank, and the lower sludge outlet is connected to the sludge thickening tank inlet; sewage The supernatant of the sludge concentration tank is returned to the waste water collection tank, and the concentrated sludge enters the sludge treatment device.
6. The mine water advanced treatment system according to claim 1, wherein the secondary microfiltration softening system and the tertiary microfiltration softening system are respectively provided with a concentrated water reaction tank and a concentrated water concentration tank; the secondary microfiltration softening system The inlet of the concentrated water reaction tank of the system is connected with the concentrated water produced by the primary reverse osmosis system, and its outlet overflows to the concentrated water concentration tank of the secondary microfiltration softening system; the inlet of the concentrated water reaction tank of the third-stage microfiltration softening system is connected to the The concentrated water produced by the two-stage reverse osmosis system is connected, and its water outlet overflows to the concentrated water concentration tank of the three-stage microfiltration softening system; Add sodium carbonate and sodium hydroxide to carry out softened water treatment; stirring systems are set in the concentrated water concentration tanks of the second-stage microfiltration softening system and the third-stage microfiltration softening system; the output of the third-stage microfiltration softening system is concentrated. The water enters the ion exchange softening system.
7. The mine water advanced treatment system according to claim 1, characterized in that, a pretreatment water production tank is set before the secondary reverse osmosis system and the ion exchange softener, which are respectively used for the secondary microfiltration softening system and the tertiary microfiltration softening system. The produced water is pretreated, acid is added to the pretreated water tank to adjust the pH to 6-9, and the alkalinity is removed by stripping.
8. The mine water advanced treatment system according to claim 4, wherein the mixed salt mother liquor produced by the shown evaporative crystallization unit and the sodium sulfate magma produced by the freezing crystallization unit are heat-exchanged to improve the sodium sulfate magma. The temperature of the mixed salt mother liquor is lowered; the evaporative condensate discharged from the single-effect evaporative crystallization unit and the mother liquor produced by the frozen crystallization unit are subjected to heat exchange, so as to increase the temperature of the mother liquor produced by the frozen crystallization unit.
9. The method for treating mine water by an advanced mine water treatment system according to claims 1-8, characterized in that, after the mine water is regulated and homogenized by the adjustment tank, it enters the V-type filter tank for filtration, and the filtrate is used as purified water, and then passes through the Ultrafiltration system, primary reverse osmosis system, secondary microfiltration softening system, secondary reverse osmosis system, tertiary microfiltration softening system, ion exchange softening system, DTRO system and evaporative crystallization salt separation system; the primary reverse osmosis system The clear liquid produced by the system, the secondary reverse osmosis system and the DTRO system is mixed as produced water and discharged into the production pool; the concentrated water produced by the primary reverse osmosis system passes through the secondary microfiltration softening system and enters the secondary reverse osmosis system. Osmosis system; the concentrated water produced by the two-stage reverse osmosis system sequentially passes through the three-stage microfiltration softening system, the ion exchange softening system, and the DTRO system. Finally, the concentrated water discharged from the DTRO system enters the evaporative crystallization and salt separation system as concentrated brine, and the output Evaporate condensate, anhydrous sodium sulfate crystalline salt and sodium chloride crystalline salt.
10. The method for treating mine water by an advanced mine water treatment system according to claim 9, wherein the conditioning tank is an aeration conditioning tank, and through aeration pre-oxidation treatment, reducing substances in wastewater are removed for homogenization adjustment , to maintain the stability of the subsequent process.
11. The method for treating mine water by an advanced mine water treatment system according to claim 9, wherein the V-type filter adopts a homogeneous filter material of quartz sand for removing colloid and SS in the water, and the turbidity of the effluent is less than or equal to 3NTU.
12. The method for treating mine water by an advanced mine water treatment system according to claim 9, wherein the ultrafiltration system adopts hollow fiber membrane elements to remove bacteria, viruses and colloidal particles in the form of cross-flow filtration, and the recovery rate is greater than or equal to 95%.
13. The method for treating mine water by an advanced mine water treatment system according to claim 9, wherein the primary reverse osmosis system adopts a rolled membrane, the recovery rate is greater than or equal to 70%, and clean water is discharged into a water production pool; The reverse osmosis system adopts roll membrane, the recovery rate is not less than 80%, and the clean water is discharged into the production tank.
14. The method for treating mine water by an advanced mine water treatment system according to claim 9, wherein the ion exchange softener adopts chelating resin, and adopts 3-4% hydrochloric acid solution and 4-5% sodium hydroxide solution for resin treatment regeneration.
15. The method for treating mine water by an advanced mine water treatment system according to claim 9, wherein the recovery rate of the DTRO system is 50-55%, the operating pressure is less than or equal to 120 bar, and the concentrated water discharged from the DTRO system is used as the mother liquor of the evaporative crystallization and salt separation system , DTRO system discharges clean water into the production tank.

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