Full-quantitative resourceful treatment device for salt-containing water

Abstract

The utility model provides a full-quantitative resourceful treatment device for salt-containing water. The full-quantitative resourceful treatment device comprises a primary fresh water recovery unit, a salt separation unit, a monovalent concentration and crystallization unit, a divalent concentration and crystallization unit and a mixed salt treatment unit, a water inlet of the first-stage fresh water recovery unit is communicated with a salt-containing water pipeline, a concentrated water outlet of the first-stage fresh water recovery unit is communicated with a water inlet of the salt separation unit, and a water outlet of the salt separation unit is respectively communicated with water inlets of the monovalent concentration crystallization unit and the divalent concentration crystallization unit; mother liquor outlets of the monovalent concentration and crystallization unit and the divalent concentration and crystallization unit are communicated with the mixed salt treatment unit, and crushed mixed salt treated by the mixed salt treatment unit enters the salt separation unit; monovalent salt and divalent salt at product outlets of the monovalent concentration and crystallization unit and the divalent concentration and crystallization unit are stored through a storage device, so that salt resources in mine water are effectively recycled, and the pollution of organic matters to the environment is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of salt water treatment, specifically relates to a salt water full-quantitative resourceful treatment device. BACKGROUND

[0002] The development of chemical industry brings great benefits to human beings, but also constitutes a potential huge environmental risk. The production of non-ferrous metal smelting, power battery production and recycling, coal chemical industry, chemical raw material synthesis and other chemicals will produce a large amount of industrial by-product high-salinity water. When industrial water is treated, the acid and alkali reagents added to the industrial wastewater to be treated are also eventually converted into salt, and further industrial water treatment will also produce industrial by-product high-salinity water. When the conventional treatment of these industrial by-product high-salinity water is carried out, the industrial by-product high-salinity water is generally concentrated and crystallized, and at the same time industrial by-product salt is obtained, and about 10% of the total salt content of mixed salt is also produced. In terms of environmental supervision, these mixed salts are usually classified as hazardous waste, and enterprises usually need to pay high fees to treat these mixed salts, which seriously reduces the profitability of enterprises.

[0003] A large amount of mixed salt is generated in the development and utilization of mine water. There is no way to resourcefully utilize these mixed salts, and enterprises have to pay for disposal, and even worse, some enterprises directly discard the mixed salt, thereby causing environmental pollution hazards. Under this background, how to effectively recover the salt resources in mine water and reduce the pollution of organic matter to the environment has become a problem that needs to be solved by mining enterprises. At the same time, sodium chloride and sodium sulfate, as basic chemical raw materials, have a wide market demand in the chemical, glass, papermaking and other industries. At present, in the process of recovering sodium chloride and sodium sulfate, the recovered wastewater is not further treated, resulting in a large amount of salt substances in the recovered wastewater, which directly pollutes the environment. UTILITARIAN CONTENT

[0004] In order to solve the technical problems encountered in the prior art, the utility model provides a salt water full-quantitative resourceful treatment device which can further treat the recovered wastewater, reduce the organic matter in the wastewater and avoid pollution of the environment when the wastewater is discarded.

[0005] In order to achieve the above purpose, the utility model provides the following technical scheme: a salt water full-quantitative resourceful treatment device, comprising a primary fresh water recovery unit, a salt separation unit, a monovalent concentration and crystallization unit, a divalent concentration and crystallization unit and a mixed salt treatment unit.

[0006] The water inlet of the primary freshwater recovery unit is communicated with the salt-containing water pipeline, the concentrated water outlet of the primary freshwater recovery unit is communicated with the water inlet of the salt separation unit, the water outlet of the salt separation unit is respectively communicated with the water inlets of the monovalent concentrated crystallization unit and the divalent concentrated crystallization unit, the mother liquor outlets of the monovalent concentrated crystallization unit and the divalent concentrated crystallization unit are communicated with the mixed salt treatment unit, and the crushed mixed salt treated by the mixed salt treatment unit enters the salt separation unit; the monovalent salt and the divalent salt at the product outlet of the monovalent concentrated crystallization unit and the divalent concentrated crystallization unit are stored through the storage device.

[0007] Preferably, the primary freshwater recovery unit comprises a first softening device, a first security filtration device, a first RO device, a first product water storage device and a concentrated water storage device; the water inlet of the first softening device is communicated with the salt-containing water pipeline to be treated, the water outlet of the first softening device is communicated with the water inlet of the first security filtration device, the water outlet of the first security filtration device is communicated with the water inlet of the first RO device, the concentrated water outlet of the first RO device is communicated with the water inlet of the concentrated water storage device, the fresh water outlet of the first RO device is communicated with the first product water storage device, and the water outlet of the concentrated water storage device is communicated with the water inlet of the salt separation unit.

[0008] Preferably, the salt separation unit comprises a mixed salt dissolving device, a second softening device, a second security filtration device, a salt separation device, a monovalent salt water phase storage device and a divalent salt water phase storage device; the water inlet of the mixed salt dissolving device is communicated with the water outlet of the concentrated water storage device, and the mixed salt dissolving device receives the crushed mixed salt, the water outlet of the mixed salt dissolving device is communicated with the water inlet of the second softening device, the water outlet of the second softening device is communicated with the water inlet of the second security filtration device, the water outlet of the second security filtration device is communicated with the water inlet of the salt separation device, the monovalent salt water phase outlet of the salt separation device is communicated with the monovalent salt water phase storage device, and the divalent salt water phase outlet is communicated with the divalent salt water phase storage device.

[0009] Preferably, the monovalent concentrated crystallization unit comprises a fourth security filtration device, a third RO device, a monovalent salt crystallization device and a monovalent salt product storage device; the water outlet of the monovalent salt water phase storage device is communicated with the water inlet of the fourth security filtration device, the water outlet of the fourth security filtration device is communicated with the water inlet of the third RO device, the concentrated water outlet of the third RO device is communicated with the water inlet of the monovalent salt crystallization device, and the product crystallized by the monovalent salt crystallization device is stored in the monovalent salt product storage device.

[0010] Preferably, the divalent concentration crystallization unit comprises a third security filter device, a second RO device, a divalent salt crystallization device and a divalent salt product storage device; the outlet of the divalent salt water phase storage device is communicated with the inlet of the third security filter device, the outlet of the third security filter device is communicated with the inlet of the second RO device, the concentrated water outlet of the second RO device is communicated with the inlet of the divalent salt crystallization device, and the product crystallized by the divalent salt crystallization device is stored in the divalent salt product storage device.

[0011] Preferably, the fresh water outlets of the third RO device and the second RO device are both communicated with the inlet of the second water production storage device.

[0012] The mother liquor outlets of the monovalent salt crystallization device and the divalent salt crystallization device are communicated with the inlet of the crystallization mother liquor storage device, and the outlet of the crystallization mother liquor storage device is communicated with the inlet of the mixed salt treatment unit.

[0013] Preferably, the mixed salt treatment unit comprises a crystallization mother liquor storage device, a mixed salt drying device, a mixed salt drying device, a mixed salt heat treatment device, a tail gas treatment device and a mixed salt crushing device; the outlet of the crystallization mother liquor storage device is communicated with the inlet of the mixed salt drying device, the solid-phase mixed salt obtained by the mixed salt drying device is dehydrated to obtain dehydrated mixed salt, the dehydrated mixed salt is treated by the mixed salt heat treatment device to obtain heat-treated mixed salt and heat-treated gas, the gas outlet of the mixed salt heat treatment device is communicated with the tail gas treatment device, the heat-treated mixed salt outlet of the mixed salt heat treatment device is communicated with the mixed salt crushing device, and the crushed mixed salt enters the mixed salt dissolving device.

[0014] The salt-containing water full-quantitative resource treatment process has the following beneficial effects:

[0015] The treatment device can fully recycle the water resources in the salt-containing water, avoids waste of water resources, and ensures that the generated mixed salt is not discharged, eliminates the cost of separately reprocessing the generated mixed salt in the later stage, reduces the treatment cost, and simultaneously protects the environment due to the recycling treatment of the mixed salt, and the monovalent salt (sodium chloride) and the divalent salt (sodium sulfate) obtained meet the recycling standards, thereby increasing economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model and the design scheme, the following will briefly introduce the drawings needed by the embodiments. The drawings in the following description are only part of the embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0017] Figure 1 This is a flowchart of the method for full-scale resource utilization of saline solution in this utility model embodiment;

[0018] Figure 2 This is a block diagram of the brine-containing resource recovery device of this utility model. Detailed Implementation

[0019] To enable those skilled in the art to better understand and implement the technical solution of this utility model, the present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of this utility model and should not be construed as limiting the scope of protection of this utility model.

[0020] like Figure 2 The embodiment shown provides a saline water resource recovery device, including a primary freshwater recovery unit, a salt separation unit, a monovalent concentration and crystallization unit, a divalent concentration and crystallization unit, and a mixed salt treatment unit.

[0021] The primary freshwater recovery unit includes a first softening device 1, a first security filter 2, a first RO device 3, a concentrate storage device 4, and a first product water storage device 5. The inlet of the first softening device 1 is connected to the saline water pipeline to be treated; the outlet of the first softening device 1 is connected to the inlet of the first security filter 2; the outlet of the first security filter 2 is connected to the inlet of the first RO device 3; the concentrate outlet of the first RO device 3 is connected to the inlet of the concentrate storage device 4; and the product water outlet of the first RO device 3... The first product water storage device 5 is connected to the inlet of the first product water storage device 5, and the outlet of the concentrated water storage device 4 is connected to the inlet of the salt separation unit. Specifically, during operation, the saline water enters the first softening device 1 through the pipeline for softening treatment. After softening treatment, the saline water enters the first security filter device 2 for filtration treatment. After filtration, the saline water enters the first RO device 3 for reverse osmosis treatment. The resulting first product water (fresh water) enters the first product water storage device 5 for storage, and the treated concentrated water is stored through the concentrated water storage device 4.

[0022] The salt separation unit includes a mixed salt dissolving device 6, a second softening device 7, a second security filter device 8, a salt separation device 9, a monovalent salt phase storage device 10, and a divalent salt phase storage device 11. The inlet of the mixed salt dissolving device 6 is connected to the outlet of the concentrated water storage device 4. The mixed salt, after being pulverized by the mixed salt treatment unit, enters the mixed salt dissolving device 6. The outlet of the mixed salt dissolving device 6 is connected to the inlet of the second softening device 7, the outlet of the second softening device 7 is connected to the inlet of the second security filter device 8, the outlet of the second security filter device 8 is connected to the inlet of the salt separation device 9, the monovalent salt phase outlet of the salt separation device 9 is connected to the inlet of the monovalent salt phase storage device 10, and the divalent salt phase outlet is connected to the inlet of the divalent salt phase storage device 11. Specifically, during the salt separation process, the salt entering the mixed salt dissolving device 6... The concentrated water and mixed salt are fully dissolved, with the concentrated water coming from the concentrated water storage device 4 and the mixed salt coming from the mixed salt treatment unit. After full dissolution, the liquid enters the second softening device 7 for softening treatment. The softened liquid then passes through the second security filtration device 8 for filtration to remove insoluble impurities, such as coke mixed in the mixed salt, to protect the nanofiltration membrane. The filtered liquid then enters the salt separation device 9 for salt separation treatment. In this embodiment, the salt separation device is a nanofiltration membrane salt separation device. When the liquid entering the nanofiltration membrane salt separation device undergoes salt separation, the liquid that permeates through the nanofiltration membrane is the monovalent salt liquid, and the liquid that is retained by the nanofiltration membrane is the divalent salt liquid. The monovalent salt liquid is stored in the monovalent salt phase storage device 10, and the divalent salt liquid is stored in the divalent salt phase storage device 11, in preparation for the crystallization of the monovalent and divalent salts.

[0023] The monovalent salt concentration and crystallization unit includes a fourth security filter 12, a third RO device 13, a monovalent salt crystallization device 14, and a monovalent salt product storage device 15. The outlet of the monovalent salt phase storage device 10 is connected to the inlet 12 of the fourth security filter, the outlet of the fourth security filter 12 is connected to the inlet of the third RO device 13, the concentrated water outlet of the third RO device 13 is connected to the inlet of the monovalent salt crystallization device 14, and the product crystallized by the monovalent salt crystallization device 14 enters the monovalent salt product storage device 15 for storage.

[0024] Before crystallization of the monovalent salt, the monovalent salt liquid is filtered through the fourth security filter device 12 to ensure the normal operation of the third RO device 13. The monovalent salt liquid that has passed through the fourth security filter device 12 enters the third RO device 13 for reverse osmosis treatment. During the reverse osmosis treatment of the monovalent salt liquid in the third RO device 13, the reverse osmosis concentrate enters the monovalent salt crystallization device 14 for monovalent salt crystallization treatment. The reverse osmosis permeate enters the second permeate storage device 20 for storage and reuse. The monovalent salt product after crystallization is stored through the monovalent salt product storage device 15, and the crystallization mother liquor enters the crystallization mother liquor storage device 21 for storage.

[0025] The divalent salt concentration and crystallization unit includes a third security filter 16, a second RO device 17, a divalent salt crystallization device 18, and a divalent salt product storage device 19. The outlet of the divalent salt water phase storage device 11 is connected to the inlet of the third security filter 16, the outlet of the third security filter 16 is connected to the inlet of the second RO device 17, the concentrated water outlet of the second RO device 17 is connected to the inlet of the divalent salt crystallization device 18, and the product crystallized by the divalent salt crystallization device 18 enters the divalent salt product storage device 19 for storage.

[0026] During the crystallization of divalent salts, the divalent salt liquid is filtered through a third safety filter device 16 to ensure the normal operation of the second RO device 17. The filtered divalent salt liquid enters the second RO device 17 for reverse osmosis treatment. After reverse osmosis treatment, the reverse osmosis concentrate enters the divalent salt crystallization device 18 for divalent salt crystallization treatment. The reverse osmosis permeate enters the second permeate storage device 20 for storage. The divalent salt product after crystallization treatment is stored through the divalent salt product storage device 19, and the crystallization mother liquor enters the crystallization mother liquor storage device 21 for storage.

[0027] The mixed salt processing unit includes a crystallization mother liquor storage device 21, a mixed salt drying device 22, a mixed salt drying unit 23, a mixed salt heat treatment device 24, a tail gas treatment device 25, and a mixed salt pulverizing device 26. The outlet of the crystallization mother liquor storage device 21 is connected to the inlet of the mixed salt drying device 22. The solid mixed salt obtained by the mixed salt drying device 22 is dehydrated by the mixed salt drying device 23 to obtain dehydrated mixed salt. The dehydrated mixed salt is processed by the mixed salt heat treatment device 24 to obtain heat-treated mixed salt and heat-treated gas. The gas outlet of the mixed salt heat treatment device 24 is connected to the tail gas treatment device 25, and the heat-treated mixed salt outlet of the mixed salt heat treatment device 24 is connected to the mixed salt pulverizing device 26. The pulverized mixed salt enters the mixed salt dissolving device 6.

[0028] The mother liquor in the crystallization mother liquor storage device 21 enters the mixed salt drying device 22 for drying treatment to obtain mixed salt. At this time, the obtained mixed salt is further placed in the mixed salt drying device 23 for drying treatment to further reduce the moisture content of the mixed salt. The dried mixed salt is placed in the mixed salt heat treatment device 24 for heat treatment. The heat treatment device used in this embodiment is a pyrolysis heat treatment device. During pyrolysis, the pyrolysis temperature is 450-600℃, the residence time is 1-30min, and the pyrolysis atmosphere includes nitrogen, air, and water vapor. After the pyrolysis is completed, the gas generated by pyrolysis enters the tail gas treatment device 25 for tail gas treatment. The tail gas is discharged after treatment to meet the standards, avoiding pollution of the environment caused by pollutants in the pyrolysis gas. The pyrolyzed mixed salt enters the mixed salt pulverizing device 26 for pulverization treatment, and then the pulverized mixed salt is added to the mixed salt dissolving device 6 for dissolution and repeated recycling.

[0029] The treatment process provided in this embodiment can fully recover water resources in saline water, avoiding waste of water resources. At the same time, the mixed salt generated during water treatment is heat-treated and then recycled into the salt separation unit, ensuring that the mixed salt is not discharged externally. This eliminates the cost of reprocessing the mixed salt separately later, reducing treatment costs. In addition, the recycling of the mixed salt has a protective effect on the environment. The monovalent salt (sodium chloride) and divalent salt (sodium sulfate) obtained meet the recycling standards, increasing economic benefits.

[0030] Based on the apparatus provided in this embodiment, a process for the full-scale resource utilization of saline water is also provided, such as... Figure 1 As shown, it includes:

[0031] The saline solution is first softened, then filtered through a first security filter, and finally treated with an RO reactor to obtain fresh water and concentrated water. The fresh water and concentrated water treated with the first RO reactor are then stored separately.

[0032] The concentrated water stored after the first RO treatment undergoes a second softening treatment, and the concentrated water after the second softening treatment undergoes a second security filtration. The liquid after the second security filtration undergoes a salt separation treatment. In this embodiment, the salt separation treatment method used is nanofiltration membrane salt separation. During the salt separation treatment, the liquid enters the nanofiltration membrane salt separation device after passing through the second security filtration. The liquid that passes through the nanofiltration membrane is a monovalent salt liquid, and the liquid that is retained by the nanofiltration membrane is a divalent salt liquid.

[0033] The monovalent salt liquid phase and divalent salt liquid phase produced after the salt separation process are stored separately to complete the salt separation process. In this embodiment, the monovalent salt water phase after the salt separation process is monovalent salt sodium chloride liquid, and the divalent salt water phase is divalent salt sodium sulfate liquid.

[0034] After separating the monovalent and divalent salts, the stored monovalent salt liquid undergoes a fourth security filtration and a third RO treatment, while the divalent salt liquid undergoes a third security filtration and a second RO treatment. The permeate from the RO treatment of both monovalent and divalent salt liquids is stored uniformly. The treated liquids are then subjected to salt crystallization treatment to obtain monovalent and divalent salt products, respectively. In this embodiment, the crystallization treatment can be performed using either natural evaporation crystallization or heated evaporation crystallization. The crystallized mother liquor is then stored to complete the crystallization of both monovalent and divalent salts. At this point, the monovalent and divalent salt products in the saline solution are effectively separated, achieving effective recovery of salt resources in the saline solution and avoiding environmental pollution. However, the crystallization mother liquor still contains a considerable amount of salts (potassium salts, ammonium salts, magnesium salts, sodium salts, calcium salts, etc.) and organic matter that have not been fully extracted. Direct discharge would still cause serious environmental pollution. Therefore, in this embodiment, the crystallization mother liquor needs further treatment.

[0035] The mother liquor is dried to obtain mixed salt. In this embodiment, the drying method can be spray drying, etc. The obtained mixed salt is dried, heat-treated and pulverized in sequence, and then added to the concentrated water after the first RO treatment for dissolution and recycling to avoid the discharge of mixed salt into the environment. At the same time, during the heat treatment process, the pollutants (such as nitrogen dioxide, ammonia and other gases) in the exhaust gas are treated to avoid air pollution.

[0036] All softening, security filtration, and RO treatments in this embodiment employ conventional methods in this technical field. Specific methods are not described in detail. For the drying of the mixed salt, one of the conventional methods in this technical field, either drum drying or fluidized bed drying, is used. During the heat treatment of the mixed salt, the COD contained in the mixed salt is decomposed into gas and coke. The gas is treated by a tail gas treatment device to meet standards before being discharged. The coke can be collected as slag during the dissolution of the mixed salt. The heat treatment method used in this embodiment is pyrolysis. During pyrolysis, the pyrolysis temperature is 450-600℃, the residence time is 1-30 minutes, and the pyrolysis atmosphere includes one or a mixture of nitrogen, air, and water vapor atmospheres. When only a nitrogen atmosphere is used, nitrogen can be obtained using an air separation system, with a nitrogen content of 30%-95%.

[0037] It should be noted that the above specific embodiments enable those skilled in the art to more fully understand this utility model, but do not limit this utility model in any way. Therefore, although this specification and embodiments have described this utility model in detail, those skilled in the art should understand that modifications or equivalent substitutions can still be made to this utility model; and all technical solutions and improvements that do not depart from the spirit and scope of this utility model are covered within the protection scope of this utility model patent. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A device for the full-scale resource utilization of saline water, characterized in that, It includes a primary freshwater recovery unit, a salt separation unit, a monovalent concentration and crystallization unit, a divalent concentration and crystallization unit, and a mixed salt treatment unit; The inlet of the primary freshwater recovery unit is connected to the saline pipeline, the outlet of the primary freshwater recovery unit is connected to the inlet of the salt separation unit, the outlet of the salt separation unit is connected to the inlets of the monovalent concentration crystallization unit and the divalent concentration crystallization unit respectively, the mother liquor outlets of the monovalent concentration crystallization unit and the divalent concentration crystallization unit are connected to the mixed salt treatment unit, and the crushed mixed salt after treatment by the mixed salt treatment unit enters the salt separation unit; the monovalent salt and divalent salt of the product outlet of the monovalent concentration crystallization unit and the divalent concentration crystallization unit are stored through a storage device.

2. The saline water full-scale resource utilization treatment device according to claim 1, characterized in that, The primary freshwater recovery unit includes a first softening device, a first security filter, a first RO device, a first product water storage device, and a concentrate storage device. The inlet of the first softening device is connected to the saline pipeline to be treated, the outlet of the first softening device is connected to the inlet of the first security filter, the outlet of the first security filter is connected to the inlet of the first RO device, the concentrate outlet of the first RO device is connected to the inlet of the concentrate storage device, the freshwater outlet of the first RO device is connected to the first product water storage device, and the outlet of the concentrate storage device is connected to the inlet of the salt separation unit.

3. The saline water full-scale resource utilization treatment device according to claim 2, characterized in that, The salt separation unit includes a mixed salt dissolving device, a second softening device, a second security filtration device, a salt separation device, a monovalent salt water phase storage device, and a divalent salt water phase storage device. The inlet of the mixed salt dissolving device is connected to the outlet of the concentrated water storage device, and the mixed salt dissolving device receives the crushed mixed salt. The outlet of the mixed salt dissolving device is connected to the inlet of the second softening device. The outlet of the second softening device is connected to the inlet of the second security filtration device. The outlet of the second security filtration device is connected to the inlet of the salt separation device. The monovalent salt water phase outlet of the salt separation device is connected to the monovalent salt water phase storage device, and the divalent salt water phase outlet is connected to the divalent salt water phase storage device.

4. The saline water full-scale resource utilization treatment device according to claim 3, characterized in that, The monovalent salt concentration and crystallization unit includes a fourth security filter, a third RO unit, a monovalent salt crystallization unit, and a monovalent salt product storage unit. The outlet of the monovalent salt phase storage unit is connected to the inlet of the fourth security filter, the outlet of the fourth security filter is connected to the inlet of the third RO unit, the concentrated water outlet of the third RO unit is connected to the inlet of the monovalent salt crystallization unit, and the product crystallized by the monovalent salt crystallization unit enters the monovalent salt product storage unit for storage.

5. The saline water full-scale resource utilization treatment device according to claim 4, characterized in that, The divalent salt concentration and crystallization unit includes a third security filter, a second RO unit, a divalent salt crystallization unit, and a divalent salt product storage unit. The outlet of the divalent salt water phase storage unit is connected to the inlet of the third security filter, the outlet of the third security filter is connected to the inlet of the second RO unit, the concentrated water outlet of the second RO unit is connected to the inlet of the divalent salt crystallization unit, and the product crystallized by the divalent salt crystallization unit enters the divalent salt product storage unit for storage.

6. The saline water full-scale resource utilization treatment device according to claim 5, characterized in that, The freshwater outlets of the third RO unit and the second RO unit are both connected to the inlet of the second product water storage unit. The mother liquor outlets of the monovalent salt crystallization device and the divalent salt crystallization device are connected to the inlet of the mother liquor storage device, and the outlet of the mother liquor storage device is connected to the inlet of the mixed salt treatment unit.

7. A saline water full-scale resource utilization treatment device according to claim 3 or 5, characterized in that, The mixed salt processing unit includes a crystallization mother liquor storage device, a mixed salt drying device, a mixed salt heat treatment device, a tail gas treatment device, and a mixed salt pulverizing device. The outlet of the crystallization mother liquor storage device is connected to the inlet of the mixed salt drying device. The solid mixed salt obtained by the mixed salt drying device is dehydrated by the mixed salt drying device to obtain dehydrated mixed salt. The dehydrated mixed salt is processed by the mixed salt heat treatment device to obtain heat-treated mixed salt and heat-treated gas. The gas outlet of the mixed salt heat treatment device is connected to the tail gas treatment device. The heat-treated mixed salt outlet of the mixed salt heat treatment device is connected to the mixed salt pulverizing device. The pulverized mixed salt enters the mixed salt dissolving device.

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