Electrodialysis method and system for preparing alkali by carbon sequestration of mirabilite tailing washing filtrate

Abstract

The invention discloses an electrodialysis method and system for preparing alkali by using mirabilite tailing washing filtrate for carbon sequestration, mirabilite tailings are used as raw materials, electrodialysis double decomposition is used as a core process, the system integrates the technologies of washing, gas absorption and the like, and synergistic alkali preparation with greenhouse gas carbon dioxide is realized; the recovery rate of sodium sulfate in the mirabilite tailings and the purity of the sodium bicarbonate product are effectively improved, meanwhile, secondary solid waste is avoided, and the influence on the environment is reduced.

Description

Technical Field

[0001] The invention relates to the field of tailings resource utilization and carbon fixation technology, and more specifically, to an electrodialysis method and system for carbon fixation and alkali production using water-washed filtrate of mirabilite tailings. Background Art

[0002] Sodium sulfate (Na2SO4) is a key raw material in many industries such as chemical, leather, textile, food and medicine, and its demand continues to grow. At present, sodium sulfate products are mainly prepared by dissolving natural thenardite (Na2SO4·10H2O) and then heating and dehydrating it to prepare anhydrous sodium sulfate. However, the thenardite tailings produced in this process contain high concentrations of sodium sulfate and other impurities. The traditional treatment method is usually open-air stacking, which not only brings safety hazards and environmental pollution problems, but also significantly reduces the comprehensive utilization rate of mineral resources, resulting in a huge waste of resources. With the improvement of environmental protection awareness and the development of technology, the resource utilization of thenardite tailings has become a research hotspot. At the same time, as one of the main anthropogenic greenhouse gases, the continuous increase in carbon dioxide emissions has become an important cause of global warming and frequent extreme climate events. Reducing carbon dioxide emissions has become a major issue that needs to be solved in the world today. In this context, the development of technologies that can combine industrial processes with carbon dioxide absorption has become a very promising carbon capture, utilization and storage solution. Traditional alkali production processes, such as the Solvay process and the Houdebang process, have been widely used, but they face many challenges due to their high energy consumption, low production efficiency and negative impact on the environment. Therefore, it is particularly urgent to explore a new, more environmentally friendly and efficient alkali production method.

[0003] Chinese patent CN112675709B provides a bipolar membrane electrodialysis device and method for producing concentrated alkali solution from seawater with carbon fixation. By setting up multiple functional units such as a carbon dioxide inlet pipeline, an alkali solution storage unit, and a brine storage unit, and using a four-compartment electrodialysis unit, the process of extracting and converting carbonate from seawater is realized. The method includes preparing alkali solution, brine, hydrochloric acid solution, sulfuric acid solution and polar liquid, and circulating them in each storage unit. At the same time, bipolar membrane electrodialysis is started after carbon dioxide is introduced into the alkali solution, and finally a high-concentration sodium bicarbonate solution is obtained with a carbon fixation rate of 30%. Compared with traditional processes, although this technology simplifies the process and improves the efficiency of bipolar membrane electrodialysis, it may face higher initial investment costs in actual applications.

[0004] Chinese patent CN115872417B provides a bipolar membrane-enhanced sodium chloride alkali production method, which achieves the production of high-purity sodium bicarbonate and ammonium chloride by setting an ammonium bicarbonate electrodialysis membrane stack and a sodium chloride electrodialysis membrane stack in an electric field and using electromigration technology to separate sodium bicarbonate and ammonium chloride. The method includes introducing refined sodium chloride waste salt and synthetic ammonium bicarbonate solution into an electrodialysis membrane stack, forming sodium bicarbonate and ammonium chloride generation channels through a selective permeable membrane, and obtaining the final product through evaporation crystallization and freezing crystallization. This technology overcomes the problems of high energy consumption and low product purity of traditional methods, but may still face the challenges of high equipment maintenance and technical thresholds.

[0005] Chinese patent CN113753923A relates to a alkali-making process for the dual recycling of ammonia and carbon dioxide by using carbide slag reaction. The reaction of ammonium bicarbonate and sodium chloride is efficiently completed through four-channel electrodialysis technology to generate sodium bicarbonate and ammonium chloride, and ammonium chloride is processed by carbide slag to generate ammonia, thereby realizing the recycling of raw materials. This process concentrates the complex traditional alkali-making process inside the four-channel electrodialysis unit, reduces pollutant emissions, and improves the utilization rate of raw materials. Although this process is environmentally friendly, it may be necessary to solve the problems of the source and treatment of carbide slag in actual applications.

[0006] Therefore, designing a alkali production method that can comprehensively utilize mirabilite tailings and greenhouse gas carbon dioxide to improve efficiency, reduce costs, and meet clean production requirements has become a difficult problem that needs to be urgently solved in this field. Summary of the invention

[0007] In view of the defects in resource utilization and carbon fixation recovery of mirabilite tailings in the prior art, the purpose of the present invention is to provide an electrodialysis method and system for carbon fixation and alkali production by using mirabilite tailings washing filtrate, and to use mirabilite tailings and greenhouse gas carbon dioxide to synergistically produce alkali, thereby effectively improving the recovery rate of sodium sulfate and the purity of sodium bicarbonate in mirabilite tailings, while avoiding the generation of secondary solid waste and reducing the impact on the environment.

[0008] To achieve the above object, the present invention adopts the following technical solution:

[0009] The first aspect of the present invention provides an electrodialysis method for carbon fixation and alkali production using water washing filtrate of mirabilite tailings, comprising the following steps:

[0010] S1, after being crushed, the mirabilite tailings are subjected to three-stage countercurrent washing, filtration and adsorption treatment, and the treated mirabilite tailings washing filtrate is added to the sodium sulfate solution storage tank;

[0011] S2, passing carbon dioxide into the bottom of the absorption tower, countercurrently contacting with ammonia water entering from the upper part of the absorption tower, and adding the obtained ammonium bicarbonate solution into the ammonium bicarbonate solution storage tank;

[0012] S3, the sodium sulfate solution in the sodium sulfate solution storage tank and the ammonium bicarbonate solution in the ammonium bicarbonate solution storage tank are pumped into corresponding compartments of the electrodialysis device respectively, and a sodium bicarbonate solution and an ammonium sulfate solution are obtained in the corresponding compartments by electrodialysis, and are discharged into the sodium bicarbonate solution storage tank and the ammonium sulfate solution storage tank respectively;

[0013] S4, the sodium bicarbonate solution in the sodium bicarbonate solution storage tank is discharged and then frozen and crystallized to obtain sodium bicarbonate crystals;

[0014] S5, the ammonium sulfate solution in the ammonium sulfate solution storage tank is discharged and then evaporated and crystallized to obtain ammonium sulfate crystals.

[0015] Preferably, in step S1:

[0016] The particle size of the crushed mirabilite tailings is less than 60 mesh;

[0017] In the mirabilite tailings washing filtrate, the concentration of sodium sulfate is 10-15%, the total COD is less than 80 mg / L, the total hardness is less than 60 mg / L, and the total suspended solids is less than 10 mg / L;

[0018] When the concentration of sodium sulfate in the sodium sulfate solution storage tank is lower than 10%, the sodium sulfate solution is added to the sodium sulfate solution storage tank.

[0019] Preferably, in step S2:

[0020] The temperature in the absorption tower is controlled at 20-40°C, the pressure is 1-3atm, the concentration of ammonia water is 10-15%, and the volume fraction of carbon dioxide is more than 80%;

[0021] The absorption rate of carbon dioxide in the absorption tower reaches 60-80%, and the concentration of the obtained ammonium bicarbonate solution is 12-16%;

[0022] When the concentration of the ammonium bicarbonate solution in the ammonium bicarbonate solution storage tank is lower than 12%, the ammonium bicarbonate solution is supplemented into the ammonium bicarbonate solution storage tank.

[0023] Preferably, in step S3, the electrodialysis device includes an anode, a cathode and a plurality of electrodialysis modules arranged between the anode and the cathode; each electrodialysis module includes a sodium sulfate compartment, a sodium bicarbonate compartment, an ammonium bicarbonate compartment and an ammonium sulfate compartment; the sodium bicarbonate compartment and the ammonium sulfate compartment are respectively arranged on both sides of the ammonium bicarbonate compartment, and a sodium sulfate compartment is respectively arranged on the outside of the ammonium sulfate compartment and the sodium bicarbonate compartment; a cation membrane is arranged between the sodium sulfate compartment and the sodium bicarbonate compartment, a cathode membrane is arranged between the sodium sulfate compartment and the ammonium sulfate compartment, a cathode membrane is arranged between the sodium bicarbonate compartment and the ammonium bicarbonate compartment, and a cation membrane is arranged between the ammonium bicarbonate compartment and the ammonium sulfate compartment.

[0024] Preferably, the sodium sulfate solution storage tank is connected to the inlet of the sodium sulfate compartment via a pump, and the sodium sulfate compartment outlet is connected to the inlet of the sodium sulfate solution storage tank;

[0025] The ammonium bicarbonate solution storage tank is connected to the inlet of the ammonium bicarbonate compartment via a pump, and the outlet of the ammonium bicarbonate compartment is connected to the inlet of the ammonium bicarbonate solution storage tank;

[0026] The sodium bicarbonate solution storage tank is connected to the inlet of the sodium bicarbonate compartment through a pump, the outlet of the sodium bicarbonate compartment is connected to the inlet of the sodium bicarbonate solution storage tank, the sodium bicarbonate solution storage tank is connected to a cooling crystallization unit, and the mother liquor outlet of the cooling crystallization unit is connected to the sodium bicarbonate solution storage tank;

[0027] The ammonium sulfate solution storage tank is connected to the inlet of the ammonium sulfate compartment through a pump, the outlet of the ammonium sulfate compartment is connected to the inlet of the ammonium sulfate solution storage tank, and the ammonium sulfate solution storage tank is connected to an evaporation crystallization unit; the condensate outlet of the evaporation crystallization unit is connected to the ammonium sulfate solution storage tank.

[0028] Preferably, the specific process of step S3 is as follows:

[0029] S31, the sodium sulfate solution in the sodium sulfate solution storage tank enters the sodium sulfate compartment of the electrodialysis device, and the ammonium bicarbonate solution in the ammonium bicarbonate solution storage tank enters the ammonium bicarbonate compartment of the electrodialysis device;

[0030] S32, electrodialysis double decomposition, under the action of voltage, the sodium ions in the sodium sulfate compartment migrate to the sodium bicarbonate compartment through the cation membrane, and the sulfate ions migrate to the ammonium sulfate compartment through the anion membrane; the ammonium ions in the ammonium bicarbonate compartment migrate to the ammonium sulfate compartment through the cation membrane, and the bicarbonate ions migrate to the sodium bicarbonate compartment through the anion membrane; the ammonium ions and the sulfate ions form an ammonium sulfate solution in the ammonium sulfate compartment, and the sodium ions and the bicarbonate ions form a sodium bicarbonate solution in the sodium bicarbonate compartment;

[0031] S33, the ammonium sulfate solution in the ammonium sulfate compartment is discharged into the ammonium sulfate solution storage tank; the sodium bicarbonate solution in the sodium bicarbonate compartment is discharged into the sodium bicarbonate solution storage tank.

[0032] Preferably, in step S32, the voltage of the electrodialysis double decomposition is set to 12-24V.

[0033] Preferably, in step S4, the production of the sodium bicarbonate crystals is batch-wise, and when the concentration of the sodium bicarbonate solution in the sodium bicarbonate solution storage tank reaches 8-10%, the electrodialysis is stopped, and the sodium bicarbonate solution is transported to the freezing crystallization unit for freezing crystallization, and the freezing temperature is controlled to be 0-10° C. The crystallization mother liquor after separating the sodium bicarbonate crystals is first used to assist the electrodialysis module in cooling, and then a part is used for washing the mirabilite tailings after adsorption, and the other part is refluxed to the sodium bicarbonate solution storage tank.

[0034] Preferably, in step S5, the ammonium sulfate crystals are produced in a batch process. When the concentration of the ammonium sulfate solution in the ammonium sulfate storage tank reaches 14-18%, the electrodialysis is stopped, and the ammonium sulfate solution is transported to the evaporation crystallization unit for evaporation crystallization. The evaporation temperature is controlled to be 70-90° C., and a part of the condensate produced by the evaporation crystallization is used for washing the mirabilite tailings after adsorption, and the other part is refluxed to the ammonium sulfate solution storage tank.

[0035] The second aspect of the present invention provides an electrodialysis system for carbon fixation and alkali production using water washing filtrate of mirabilite tailings, comprising:

[0036] Sodium sulfate raw material unit, used to crush, three-stage countercurrent water washing, filtration, adsorption treatment of mirabilite tailings and then add them into the sodium sulfate solution storage tank;

[0037] The ammonium bicarbonate raw material unit is used to pass carbon dioxide into the bottom of the absorption tower to countercurrently contact with ammonia water entering from the upper part of the absorption tower to synthesize ammonium bicarbonate, and then add it into the ammonium bicarbonate solution storage tank;

[0038] The electrodialysis device is connected to the sodium sulfate solution storage tank and the ammonium bicarbonate solution storage tank respectively, and is used to perform electrodialysis double decomposition on the sodium sulfate solution and the ammonium bicarbonate solution to obtain the sodium bicarbonate solution and the ammonium sulfate solution in the corresponding sodium bicarbonate compartment and the ammonium sulfate compartment respectively;

[0039] a sodium bicarbonate production unit, comprising a sodium bicarbonate storage tank connected to the outlet of the sodium bicarbonate compartment and a freezing crystallization unit connected to the outlet of the sodium bicarbonate storage tank;

[0040] An ammonium sulfate product unit, comprising an ammonium sulfate solution storage tank connected to the outlet of the ammonium sulfate compartment and an evaporation crystallization unit connected to the outlet of the ammonium sulfate solution storage tank;

[0041] The electrodialysis system for producing alkali by carbon fixation using water-washed filtrate of mirabilite tailings is used to execute the electrodialysis method for producing alkali by carbon fixation using water-washed filtrate of mirabilite tailings as described in the first aspect of the present invention.

[0042] Preferably, the electrodialysis device comprises an anode, a cathode and a plurality of electrodialysis modules arranged between the anode and the cathode; each electrodialysis module comprises a sodium sulfate compartment, a sodium bicarbonate compartment, an ammonium bicarbonate compartment and an ammonium sulfate compartment; the sodium bicarbonate compartment and the ammonium sulfate compartment are respectively arranged on both sides of the ammonium bicarbonate compartment, and a sodium sulfate compartment is respectively arranged on the outside of the ammonium sulfate compartment and the sodium bicarbonate compartment; a cation membrane is arranged between the sodium sulfate compartment and the sodium bicarbonate compartment, a cathode membrane is arranged between the sodium sulfate compartment and the ammonium sulfate compartment, a cathode membrane is arranged between the sodium bicarbonate compartment and the ammonium bicarbonate compartment, and a cation membrane is arranged between the ammonium bicarbonate compartment and the ammonium sulfate compartment.

[0043] Preferably, the sodium sulfate solution storage tank is connected to the inlet of the sodium sulfate compartment via a pump, and the sodium sulfate compartment outlet is connected to the inlet of the sodium sulfate solution storage tank;

[0044] The ammonium bicarbonate solution storage tank is connected to the inlet of the ammonium bicarbonate compartment via a pump, and the outlet of the ammonium bicarbonate compartment is connected to the inlet of the ammonium bicarbonate solution storage tank;

[0045] The sodium bicarbonate solution storage tank is connected to the inlet of the sodium bicarbonate compartment through a pump, and the mother liquor outlet of the cooling crystallization unit is connected to the sodium bicarbonate solution storage tank;

[0046] The ammonium sulfate solution storage tank is connected to the inlet of the ammonium sulfate compartment through a pump, and the condensate outlet of the evaporation crystallization unit is connected to the ammonium sulfate solution storage tank.

[0047] Preferably, the anode and cathode electrodes of the electrodialysis device are iridium-tantalum coated titanium electrodes.

[0048] The effects of the present invention are as follows:

[0049] 1. The present invention makes full use of the abundant sodium sulfate resources in the washing filtrate of the mirabilite tailings, and realizes an efficient and energy-saving alkali production process through an improved electrodialysis device, while promoting the secondary utilization of carbon dioxide, improving the overall utilization rate of raw materials, and effectively reducing production costs;

[0050] 2. The present invention utilizes tailings as resources and produces sodium bicarbonate products through the method of electrodialysis double decomposition, and at the same time realizes the capture and storage of greenhouse gas carbon dioxide; this innovative process effectively improves the recovery rate of sodium sulfate and the purity of sodium bicarbonate in mirabilite tailings, while avoiding the generation of secondary solid waste and reducing the impact on the environment; in addition, the raw materials used in the method are easily available, the reaction is environmentally friendly, and it has good economic benefits and market application prospects, which helps to promote the goal of sustainable development;

[0051] 3. The present invention aims at the mirabilite tailings, realizes the recycling of solid waste resources and promotes the circular economy;

[0052] 4. The method of the present invention can absorb greenhouse gas carbon dioxide, realize the capture and storage of carbon dioxide, and convert it into industrial products, which is in line with the dual carbon concept and helps enterprises achieve pollution reduction and carbon reduction;

[0053] 5. The present invention uses mirabilite tailings as raw materials to produce alkali, adopts electrodialysis double decomposition process, and synergistically fixes carbon to produce two products at the same time, thereby increasing market value;

[0054] 6. The electrodialysis equipment used in the present invention has a simple structure and high integration, and can be miniaturized and skid-mounted, which is conducive to small-scale production;

[0055] 7. The present invention optimizes the electrodialysis double decomposition process, improves reaction efficiency, reduces operating costs, produces products with high purity, and has zero emissions during the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a flow chart of the electrodialysis method for carbon fixation and alkali production using water washing filtrate of mirabilite tailings of the present invention;

[0057] In the figure, 1. absorption tower; 2. ammonium bicarbonate solution storage tank; 3. sodium sulfate solution storage tank; 4. anode; 5. cathode; 6. electrodialysis module; 7. ammonium sulfate solution storage tank; 8. sodium bicarbonate solution storage tank; A. sodium sulfate compartment; B. ammonium sulfate compartment; C. ammonium bicarbonate compartment; D. sodium bicarbonate compartment. DETAILED DESCRIPTION

[0058] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0059] Combination Figure 1 As shown, the present invention provides an electrodialysis method for carbon fixation and alkali production using mirabilite tailings washing filtrate, comprising the following steps:

[0060] S1, after the mirabilite tailings are crushed, they are subjected to three-stage countercurrent washing, filtration and adsorption treatment, and the treated mirabilite tailings washing filtrate is added to the sodium sulfate solution storage tank 3;

[0061] In this step, the main purpose is to prepare the sodium sulfate-containing mirabilite tailings washing filtrate. In the sodium sulfate raw material unit, the mirabilite tailings are crushed to a particle size of less than 60 meshes, and then subjected to three-stage countercurrent washing, filtration and adsorption treatment to obtain the mirabilite tailings washing filtrate, and the mirabilite tailings washing filtrate is added to the sodium sulfate solution storage tank 3. Among them, in the mirabilite tailings washing filtrate, the concentration of sodium sulfate is 10-15%, the total COD is less than 80 mg / L, the total hardness is less than 60 mg / L, and the total suspended matter is less than 10 mg / L; during the operation of the device, when the concentration of sodium sulfate in the sodium sulfate solution storage tank 3 is lower than 10%, it is necessary to add sodium sulfate solution to the sodium sulfate solution storage tank 3 to ensure the concentration of sodium sulfate in the circulating fluid.

[0062] S2, passing carbon dioxide into the bottom of the absorption tower 1, countercurrently contacting with the ammonia water entering from the upper part of the absorption tower 1, and adding the obtained ammonium bicarbonate solution into the ammonium bicarbonate solution storage tank 2;

[0063] In this step, the main purpose is to prepare an ammonium bicarbonate solution. Carbon dioxide (CO2) is introduced into the bottom of the absorption tower 1, and countercurrently contacts with ammonia water introduced into the upper part of the absorption tower 1 to obtain an ammonium bicarbonate solution, and the absorbed gas is discharged from the top of the absorption tower 1; and the ammonium bicarbonate solution is added to the ammonium bicarbonate solution storage tank 2; in the above process, the ammonium bicarbonate solution is synthesized by ammonia water and carbon dioxide in the absorption tower 1, ammonia water is sprayed into the top of the tower, and carbon dioxide is introduced into the bottom of the tower to achieve carbon fixation; wherein, the temperature in the absorption tower 1 is controlled at 20-40°C, the pressure is 1-3atm, the concentration of ammonia water is 10-15%, and the volume fraction of carbon dioxide is more than 80%; the absorption rate of carbon dioxide in the absorption tower 1 reaches 60-80%, and the concentration of the obtained ammonium bicarbonate solution is 12-16%; during the operation of the device, when the concentration of the ammonium bicarbonate solution in the ammonium bicarbonate solution storage tank 2 is lower than 12%, the ammonium bicarbonate solution is added to the ammonium bicarbonate solution storage tank 2 to ensure the concentration of ammonium bicarbonate in the circulating fluid.

[0064] S3, the sodium sulfate solution in the sodium sulfate solution storage tank 3 and the ammonium bicarbonate solution in the ammonium bicarbonate solution storage tank 2 are pumped into corresponding compartments of the electrodialysis device, and a sodium bicarbonate solution and an ammonium sulfate solution are obtained in the corresponding compartments by electrodialysis, and are discharged into the sodium bicarbonate solution storage tank and the ammonium sulfate solution storage tank respectively;

[0065] This step mainly involves electrodialysis double decomposition reaction to synthesize sodium bicarbonate and ammonium sulfate, and the specific process is as follows:

[0066] S31, the sodium sulfate solution in the sodium sulfate solution storage tank 3 enters the sodium sulfate compartment A of the electrodialysis device, and the ammonium bicarbonate solution in the ammonium bicarbonate solution storage tank 2 enters the ammonium bicarbonate compartment C of the electrodialysis device;

[0067] S32, electrodialysis double decomposition, under the action of voltage, the sodium ions in the sodium sulfate compartment A migrate to the sodium bicarbonate compartment D through the cation membrane, and the sulfate ions migrate to the ammonium sulfate compartment B through the anion membrane; the ammonium ions in the ammonium bicarbonate compartment C migrate to the ammonium sulfate compartment B through the cation membrane, and the bicarbonate ions migrate to the sodium bicarbonate compartment D through the anion membrane; the ammonium ions and the sulfate ions form an ammonium sulfate solution in the ammonium sulfate compartment B, and the sodium ions and the bicarbonate ions form a sodium bicarbonate solution in the sodium bicarbonate compartment D;

[0068] S33, the ammonium sulfate solution in the ammonium sulfate compartment is discharged into the ammonium sulfate solution storage tank; the sodium bicarbonate solution in the sodium bicarbonate compartment is discharged into the sodium bicarbonate solution storage tank.

[0069] In the above electrodialysis double decomposition process, the overall reaction formula is: Na2SO4+NH4HCO3=NaHCO3+(NH4)2SO4. The constant voltage of the electrodialysis double decomposition is set to 12-24V;

[0070] The electrodialysis device used above comprises an anode 4, a cathode 5 and a plurality of electrodialysis modules 6 arranged between the anode 4 and the cathode 5; the electrodialysis module 6 adopts a four-compartment configuration method to form an independent reaction channel to complete the electrodialysis double decomposition reaction, and each electrodialysis module 6 comprises a sodium sulfate compartment A, a sodium bicarbonate compartment D, an ammonium bicarbonate compartment C, and an ammonium sulfate compartment B; the sodium bicarbonate compartment D and the ammonium sulfate compartment B are respectively arranged on both sides of the ammonium bicarbonate compartment C, and the outer sides of the ammonium sulfate compartment B and the sodium bicarbonate compartment D are respectively provided with a sodium sulfate compartment A; a cation membrane is arranged between the sodium sulfate compartment A and the sodium bicarbonate compartment D, a negative membrane is arranged between the sodium sulfate compartment A and the ammonium sulfate compartment B, a negative membrane is arranged between the sodium bicarbonate compartment D and the ammonium bicarbonate compartment C, and a cation membrane is arranged between the ammonium bicarbonate compartment C and the ammonium sulfate compartment B. The cation membrane can be a homogeneous cation exchange membrane (CEM), and the negative membrane can be a homogeneous anion exchange membrane (AEM).

[0071] The operation mode of the above-mentioned electrodialysis device is as follows:

[0072] The sodium sulfate solution storage tank 3 is connected to the inlet of the sodium sulfate compartment A through a pump, and the outlet of the sodium sulfate compartment A is connected to the inlet of the sodium sulfate solution storage tank 3 to form an independent circulation reaction channel;

[0073] The ammonium bicarbonate solution storage tank 2 is connected to the inlet of the ammonium bicarbonate compartment C through a pump, and the outlet of the ammonium bicarbonate compartment C is connected to the inlet of the ammonium bicarbonate solution storage tank 2 to form an independent circulation reaction channel;

[0074] The sodium bicarbonate solution storage tank 8 is connected to the inlet of the sodium bicarbonate compartment D through a pump, and the outlet of the sodium bicarbonate compartment D is connected to the inlet of the sodium bicarbonate solution storage tank 8 to form an independent circulation reaction channel; the sodium bicarbonate solution storage tank 8 is connected to the cooling crystallization unit, and the mother liquor outlet of the cooling crystallization unit is connected to the sodium bicarbonate solution storage tank 8;

[0075] The ammonium sulfate solution storage tank 7 is connected to the condensate outlet inlet of the ammonium sulfate compartment B through a pump, and the outlet of the ammonium sulfate compartment B is connected to the inlet of the ammonium sulfate solution storage tank 7 to form an independent circulation reaction channel; the ammonium sulfate solution storage tank 7 is connected to the evaporation crystallization unit; the condensate outlet of the evaporation crystallization unit is connected to the ammonium sulfate solution storage tank 7.

[0076] S4, the sodium bicarbonate solution in the sodium bicarbonate storage tank 8 is discharged and then frozen and crystallized to obtain sodium bicarbonate crystals;

[0077] In this step, the production of sodium bicarbonate crystals is batch-wise. When the concentration of the sodium bicarbonate solution in the sodium bicarbonate solution storage tank 8 reaches 8-10%, the electrodialysis is stopped, and the sodium bicarbonate solution is transported to the freezing crystallization unit for freezing crystallization. The freezing temperature is controlled to be 0-10°C. The crystallization mother liquor after separating the sodium bicarbonate crystals can first be used to assist the electrodialysis module in cooling, and then a part of it is used for washing the mirabilite tailings after adsorption, and the other part is refluxed to the sodium bicarbonate solution storage tank 8 for the next batch of production.

[0078] S5, the ammonium sulfate solution in the ammonium sulfate solution storage tank 7 is discharged and then evaporated and crystallized to obtain ammonium sulfate crystals.

[0079] In this step, the production of ammonium sulfate crystals is batch-wise. When the concentration of the ammonium sulfate solution in the ammonium sulfate solution storage tank 7 reaches 14-18%, the electrodialysis is stopped, and the ammonium sulfate solution is transported to the evaporation crystallization unit for evaporation crystallization. The evaporation temperature is controlled to be 70-90° C. A part of the condensate produced by the evaporation crystallization is used for washing the mirabilite tailings after adsorption, and the other part is refluxed to the ammonium sulfate solution storage tank 7 for the next batch of production.

[0080] In the above method, the generation and replenishment of sodium sulfate and ammonium bicarbonate are both batch operations, the electrodialysis of sodium sulfate and ammonium bicarbonate are both continuous operations, and the production of sodium bicarbonate and ammonium sulfate is batch operation. Sodium sulfate, ammonium bicarbonate, sodium bicarbonate, and ammonium sulfate solution are circulated independently. In this method, the total conversion rate of sodium sulfate is maintained at more than 90%, and the purity of the prepared sodium bicarbonate crystals and ammonium sulfate crystals reaches more than 95%.

[0081] Combination Figure 1As shown, the present invention also provides an electrodialysis system for carbon fixation and alkali production using water washing filtrate of mirabilite tailings, including a sodium sulfate raw material unit, an ammonium bicarbonate raw material unit, an electrodialysis device, a sodium bicarbonate product unit and an ammonium sulfate product unit. The sodium sulfate raw material unit is used to crush the mirabilite tailings, perform three-stage countercurrent water washing, filtration, and adsorption treatment, and then add them to the sodium sulfate solution storage tank 3. The ammonium bicarbonate raw material unit is used to pass carbon dioxide into the bottom of the absorption tower 1 and countercurrently contact with ammonia water entering the upper part of the absorption tower 1 to synthesize ammonium bicarbonate, and then add it to the ammonium bicarbonate solution storage tank 2. The electrodialysis device is connected to the sodium sulfate solution storage tank 3 and the ammonium bicarbonate solution storage tank 2, respectively, to perform electrodialysis double decomposition on the sodium sulfate solution and the ammonium bicarbonate solution, and obtain the sodium bicarbonate solution and the ammonium sulfate solution in the corresponding sodium bicarbonate compartment D and the ammonium sulfate compartment B, respectively. The sodium bicarbonate product unit includes a sodium bicarbonate solution storage tank 8 connected to the outlet of the sodium bicarbonate compartment D and a freezing crystallization unit connected to the sodium bicarbonate solution storage tank 8. The ammonium sulfate product unit comprises an ammonium sulfate solution storage tank 7 connected to the outlet of the ammonium sulfate compartment B and an evaporation crystallization unit connected to the ammonium sulfate solution storage tank 7.

[0082] Combination Figure 1 As shown, the electrodialysis device includes an anode 4, a cathode 5 and a plurality of electrodialysis modules 6 arranged between the anode 4 and the cathode 5; each electrodialysis module 6 includes a sodium sulfate compartment A, a sodium bicarbonate compartment D, an ammonium bicarbonate compartment C and an ammonium sulfate compartment B; the sodium bicarbonate compartment D and the ammonium sulfate compartment B are respectively arranged on both sides of the ammonium bicarbonate compartment C, and the outer sides of the ammonium sulfate compartment B and the sodium bicarbonate compartment D are respectively provided with a sodium sulfate compartment A; a cation membrane is arranged between the sodium sulfate compartment A and the sodium bicarbonate compartment D, a cathode membrane is arranged between the sodium sulfate compartment A and the ammonium sulfate compartment B, a cathode membrane is arranged between the sodium bicarbonate compartment D and the ammonium bicarbonate compartment C, and a cation membrane is arranged between the ammonium bicarbonate compartment C and the ammonium sulfate compartment B.

[0083] Combination Figure 1 As shown, the sodium sulfate solution storage tank 3 is connected to the inlet of the sodium sulfate compartment A through a pump, and the outlet of the sodium sulfate compartment A is connected to the inlet of the sodium sulfate solution storage tank 3;

[0084] Combination Figure 1 As shown, the ammonium bicarbonate solution storage tank 2 is connected to the inlet of the ammonium bicarbonate compartment C through a pump, and the outlet of the ammonium bicarbonate compartment C is connected to the inlet of the ammonium bicarbonate solution storage tank 2.

[0085] Combination Figure 1 As shown, the sodium bicarbonate solution storage tank 8 is connected to the inlet of the sodium bicarbonate compartment D through a pump, and the mother liquor outlet of the cooling crystallization unit is connected to the sodium bicarbonate solution storage tank 8;

[0086] Combination Figure 1As shown, the ammonium sulfate solution storage tank 7 is connected to the inlet of the ammonium sulfate compartment B through a pump, and the condensate outlet of the evaporation crystallization unit is connected to the ammonium sulfate solution storage tank 7.

[0087] In a specific embodiment, the anode electrode 4 and the cathode electrode 5 of the electrodialysis device are iridium-tantalum coated titanium electrodes.

[0088] Example 1

[0089] refer to Figure 1 As shown, the present embodiment provides an electrodialysis method for carbon fixation and alkali production using water washing filtrate of mirabilite tailings, comprising the following steps:

[0090] (1) The mirabilite tailings are crushed to a particle size of less than 60 mesh, and then subjected to three-stage countercurrent washing, filtration, and adsorption. The sodium sulfate concentration in the mirabilite tailings washing filtrate is 12%, the total COD is 50 mg / L, the total hardness is 50 mg / L, the total heavy metals are 5 mg / L, and the total suspended solids are 5 mg / L. This solution is pumped into the sodium sulfate solution storage tank 3.

[0091] (2) Carbon dioxide is introduced into the bottom of absorption tower 1 at a volume fraction of 85%, and is countercurrently contacted with 12% ammonia water sprayed into the top of the tower. The temperature is controlled to be 30° C. and the pressure is 2 atm. The absorbed gas is discharged from the top of the tower, and the obtained ammonium bicarbonate solution has a concentration of 14%. This solution is pumped into ammonium bicarbonate solution storage tank 2.

[0092] (3) The solutions in the sodium sulfate solution storage tank 3 and the ammonium bicarbonate solution storage tank 2 are pumped into the corresponding compartments of the electrodialysis device, respectively, and the constant voltage is set to 18V. The electrodialysis device adopts a four-compartment design, and each compartment is separated by a homogeneous anion exchange membrane (AEM) and a homogeneous cation exchange membrane (CEM). Under the action of the electric field, ammonium ions and sodium ions migrate to the ammonium sulfate compartment B and the sodium bicarbonate compartment D, respectively, while sulfate ions and bicarbonate ions migrate to the ammonium sulfate compartment B and the sodium bicarbonate compartment D, respectively, to generate ammonium sulfate solution and sodium bicarbonate solution, respectively. The ammonium sulfate solution and the sodium bicarbonate solution flow into the ammonium sulfate solution storage tank 7 and the sodium bicarbonate solution storage tank 8, respectively.

[0093] (4) When the concentration of the sodium bicarbonate solution in the sodium bicarbonate solution storage tank 8 reaches 9%, it is pumped into the freezing crystallization unit, and the freezing temperature is set to 5° C. After the sodium bicarbonate crystals are separated, half of the mother liquor is used for washing the mirabilite tailings after adsorption, and the other half is refluxed to the sodium bicarbonate solution storage tank 8 for the next batch of production.

[0094] (5) When the concentration of the ammonium sulfate solution in the ammonium sulfate solution storage tank 7 reaches 16%, it is pumped into the evaporation crystallization unit, and the evaporation temperature is set to 80° C. After the ammonium sulfate crystals are separated, half of the condensate is used for washing the mirabilite tailings after adsorption, and the other half is refluxed to the ammonium sulfate solution storage tank 7 for the next batch of production.

[0095] Throughout the process, the generation and replenishment of sodium sulfate and ammonium bicarbonate are batch operations, while the electrodialysis process is continuous. Ultimately, the total conversion rate of sodium sulfate reaches 90%, and the purity of sodium bicarbonate crystals and ammonium sulfate crystals both reach over 95%.

[0096] Example 2

[0097] refer to Figure 1 As shown, the present embodiment provides an electrodialysis method for carbon fixation and alkali production using water washing filtrate of mirabilite tailings, comprising the following steps:

[0098] (1) The mirabilite tailings are crushed to a particle size of 80 mesh, and then subjected to three-stage countercurrent washing, filtration, and adsorption. The sodium sulfate concentration in the treated mirabilite tailings washing filtrate is 14%, the total COD is 30 mg / L, the total hardness is 30 mg / L, the total heavy metals are 4 mg / L, and the total suspended solids are 2 mg / L. This solution is pumped into the sodium sulfate solution storage tank 3.

[0099] (2) Carbon dioxide is introduced into the absorption tower 1 at a volume fraction of 90%, and countercurrently contacts with 14% ammonia water at 25° C. and 2.5 atm to obtain an ammonium bicarbonate solution with a concentration of 16%. The solution is pumped into the ammonium bicarbonate solution storage tank 2.

[0100] (3) Sodium sulfate solution and ammonium bicarbonate solution are pumped into the electrodialysis device respectively, and the constant voltage is set to 22V. The electrodialysis device also adopts a four-compartment design, and each compartment is separated by a homogeneous anion exchange membrane (AEM) and a homogeneous cation exchange membrane (CEM). Under the action of the electric field, ammonium ions and sodium ions migrate to the ammonium sulfate compartment B and the sodium bicarbonate compartment D respectively, while sulfate ions and bicarbonate ions migrate to the ammonium sulfate compartment B and the sodium bicarbonate compartment D respectively, generating ammonium sulfate solution and sodium bicarbonate solution respectively. The ammonium sulfate solution and the sodium bicarbonate solution flow into the ammonium sulfate solution storage tank 7 and the sodium bicarbonate solution storage tank 8 respectively.

[0101] (4) When the concentration of the sodium bicarbonate solution in the sodium bicarbonate solution storage tank 8 reaches 10%, it is pumped into the freezing crystallization unit, and the freezing temperature is set to 3° C. After the sodium bicarbonate crystals are separated, half of the mother liquor is used for washing the mirabilite tailings after adsorption, and the other half is refluxed to the sodium bicarbonate solution storage tank 8 for the next batch of production.

[0102] (5) When the concentration of the ammonium sulfate solution in the ammonium sulfate solution storage tank 7 reaches 18%, it is pumped into the evaporation crystallization unit, and the evaporation temperature is set to 85° C. After the ammonium sulfate crystals are separated, half of the condensate is used for washing the mirabilite tailings after adsorption, and the other half is refluxed to the ammonium sulfate solution storage tank 7 for the next batch of production.

[0103] Through the above optimization measures, the total conversion rate of sodium sulfate was increased to 95%, and the product purity of sodium bicarbonate and ammonium sulfate reached more than 98%.

[0104] Example 3

[0105] refer to Figure 1 As shown, the present embodiment provides an electrodialysis method for carbon fixation and alkali production using water washing filtrate of mirabilite tailings, comprising the following steps:

[0106] (1) The mirabilite tailings are crushed to a particle size of 80 mesh, and then subjected to three-stage countercurrent washing, filtration, and adsorption. The sodium sulfate concentration in the treated mirabilite tailings washing filtrate is 14%, the total COD is 10 mg / L, the total hardness is 5 mg / L, the total heavy metals are 3 mg / L, and the total suspended solids are 2 mg / L. This solution is pumped into the sodium sulfate solution storage tank 3.

[0107] (2) Carbon dioxide is introduced into the absorption tower 1 at a volume fraction of 95%, and countercurrently contacts with 14% ammonia water at 20° C. and 1.5 atm to obtain an ammonium bicarbonate solution with a concentration of 16%. The solution is pumped into the ammonium bicarbonate solution storage tank 2.

[0108] (3) Sodium sulfate solution and ammonium bicarbonate solution are pumped into the electrodialysis device respectively, and the constant voltage is set to 24V. The electrodialysis device also adopts a four-compartment design, and each compartment is separated by a homogeneous anion exchange membrane (AEM) and a homogeneous cation exchange membrane (CEM). Under the action of the electric field, ammonium ions and sodium ions migrate to the ammonium sulfate compartment B and the sodium bicarbonate compartment D respectively, while sulfate ions and bicarbonate ions migrate to the ammonium sulfate compartment B and the sodium bicarbonate compartment D respectively, generating ammonium sulfate solution and sodium bicarbonate solution respectively. The ammonium sulfate solution and the sodium bicarbonate solution flow into the ammonium sulfate solution storage tank 7 and the sodium bicarbonate solution storage tank 8 respectively.

[0109] (4) When the concentration of the sodium bicarbonate solution in the sodium bicarbonate solution storage tank 8 reaches 10%, it is pumped into the freezing crystallization unit, and the freezing temperature is set to 0° C. After the sodium bicarbonate crystals are separated, half of the mother liquor is used for washing the mirabilite tailings after adsorption, and the other half is refluxed to the sodium bicarbonate solution storage tank 8 for the next batch of production.

[0110] (5) When the concentration of the ammonium sulfate solution in the ammonium sulfate solution storage tank 7 reaches 18%, it is pumped into the evaporation crystallization unit, and the evaporation temperature is set to 90° C. After the ammonium sulfate crystals are separated, half of the condensate is used for washing the mirabilite tailings after adsorption, and the other half is refluxed to the ammonium sulfate solution storage tank 7 for the next batch of production.

[0111] In this embodiment, the total conversion rate of sodium sulfate is maintained at above 98%, and the product purities of sodium bicarbonate and ammonium sulfate are both above 99%.

[0112] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. An electrodialysis method for carbon fixation and alkali production using water filtrate of mirabilite tailings, characterized in that: The following steps are involved: S1, after being crushed, the mirabilite tailings are subjected to three-stage countercurrent washing, filtration and adsorption treatment, and the treated mirabilite tailings washing filtrate is added to the sodium sulfate solution storage tank; S2, passing carbon dioxide into the bottom of the absorption tower, countercurrently contacting with ammonia water entering from the upper part of the absorption tower, and adding the obtained ammonium bicarbonate solution into the ammonium bicarbonate solution storage tank; S3, the sodium sulfate solution in the sodium sulfate solution storage tank and the ammonium bicarbonate solution in the ammonium bicarbonate solution storage tank are pumped into corresponding compartments of the electrodialysis device respectively, and a sodium bicarbonate solution and an ammonium sulfate solution are obtained in the corresponding compartments by electrodialysis, and are discharged into the sodium bicarbonate solution storage tank and the ammonium sulfate solution storage tank respectively; S4, the sodium bicarbonate solution in the sodium bicarbonate solution storage tank is discharged and then frozen and crystallized to obtain sodium bicarbonate crystals; S5, the ammonium sulfate solution in the ammonium sulfate solution storage tank is discharged and then evaporated and crystallized to obtain ammonium sulfate crystals.

2. The electrodialysis method for carbon fixation and alkali production using the filtrate from the washing of mirabilite tailings according to claim 1, characterized in that: In step S1: The particle size of the crushed mirabilite tailings is less than 60 mesh; In the mirabilite tailings washing filtrate, the concentration of sodium sulfate is 10-15%, the total COD is less than 80 mg / L, the total hardness is less than 60 mg / L, and the total suspended solids is less than 10 mg / L; When the concentration of sodium sulfate in the sodium sulfate solution storage tank is lower than 10%, the sodium sulfate solution is added to the sodium sulfate solution storage tank.

3. The electrodialysis method for carbon fixation and alkali production using the filtrate from the washing of mirabilite tailings according to claim 1, characterized in that: In step S2: The temperature in the absorption tower is controlled at 20-40°C, the pressure is 1-3atm, the concentration of ammonia water is 10-15%, and the volume fraction of carbon dioxide is more than 80%; The absorption rate of carbon dioxide in the absorption tower reaches 60-80%, and the concentration of the obtained ammonium bicarbonate solution is 12-16%; When the concentration of the ammonium bicarbonate solution in the ammonium bicarbonate solution storage tank is lower than 12%, the ammonium bicarbonate solution is supplemented into the ammonium bicarbonate solution storage tank.

4. The electrodialysis method for carbon fixation and alkali production using the filtrate from the washing of mirabilite tailings according to claim 1, characterized in that: In step S3, the electrodialysis device includes an anode, a cathode and a plurality of electrodialysis modules arranged between the anode and the cathode; each electrodialysis module includes a sodium sulfate compartment, a sodium bicarbonate compartment, an ammonium bicarbonate compartment and an ammonium sulfate compartment; the sodium bicarbonate compartment and the ammonium sulfate compartment are respectively arranged on both sides of the ammonium bicarbonate compartment, and a sodium sulfate compartment is respectively arranged on the outside of the ammonium sulfate compartment and the sodium bicarbonate compartment; a cation membrane is arranged between the sodium sulfate compartment and the sodium bicarbonate compartment, a cathode membrane is arranged between the sodium sulfate compartment and the ammonium sulfate compartment, a cathode membrane is arranged between the sodium bicarbonate compartment and the ammonium bicarbonate compartment, and a cation membrane is arranged between the ammonium bicarbonate compartment and the ammonium sulfate compartment.

5. The electrodialysis method for carbon fixation and alkali production using the filtrate from the washing of mirabilite tailings according to claim 4, characterized in that: The sodium sulfate solution storage tank is connected to the inlet of the sodium sulfate compartment through a pump, and the sodium sulfate compartment outlet is connected to the inlet of the sodium sulfate solution storage tank; The ammonium bicarbonate solution storage tank is connected to the inlet of the ammonium bicarbonate compartment via a pump, and the outlet of the ammonium bicarbonate compartment is connected to the inlet of the ammonium bicarbonate solution storage tank; The sodium bicarbonate solution storage tank is connected to the inlet of the sodium bicarbonate compartment through a pump, the outlet of the sodium bicarbonate compartment is connected to the inlet of the sodium bicarbonate solution storage tank, the sodium bicarbonate solution storage tank is connected to a cooling crystallization unit, and the mother liquor outlet of the cooling crystallization unit is connected to the sodium bicarbonate solution storage tank; The ammonium sulfate solution storage tank is connected to the inlet of the ammonium sulfate compartment through a pump, the outlet of the ammonium sulfate compartment is connected to the inlet of the ammonium sulfate solution storage tank, and the ammonium sulfate solution storage tank is connected to an evaporation crystallization unit; the condensate outlet of the evaporation crystallization unit is connected to the ammonium sulfate solution storage tank.

6. The electrodialysis method for carbon fixation and alkali production using the filtrate from the washing of mirabilite tailings according to claim 1, characterized in that: The specific process of step S3 is as follows: S31, the sodium sulfate solution in the sodium sulfate solution storage tank enters the sodium sulfate compartment of the electrodialysis device, and the ammonium bicarbonate solution in the ammonium bicarbonate solution storage tank enters the ammonium bicarbonate compartment of the electrodialysis device; S32, electrodialysis double decomposition, under the action of voltage, the sodium ions in the sodium sulfate compartment migrate to the sodium bicarbonate compartment through the cation membrane, and the sulfate ions migrate to the ammonium sulfate compartment through the anion membrane; the ammonium ions in the ammonium bicarbonate compartment migrate to the ammonium sulfate compartment through the cation membrane, and the bicarbonate ions migrate to the sodium bicarbonate compartment through the anion membrane; the ammonium ions and the sulfate ions form an ammonium sulfate solution in the ammonium sulfate compartment, and the sodium ions and the bicarbonate ions form a sodium bicarbonate solution in the sodium bicarbonate compartment; S33, the ammonium sulfate solution in the ammonium sulfate compartment is discharged into the ammonium sulfate solution storage tank; the sodium bicarbonate solution in the sodium bicarbonate compartment is discharged into the sodium bicarbonate solution storage tank.

7. The electrodialysis method for carbon fixation and alkali production using the filtrate from washing of mirabilite tailings according to claim 6, characterized in that: In the step S32, the voltage of the electrodialysis double decomposition is set to 12-24V.

8. The electrodialysis method for carbon fixation and alkali production using the filtrate from the washing of mirabilite tailings according to claim 1, characterized in that: In step S4, the production of the sodium bicarbonate crystals is batch-wise. When the concentration of the sodium bicarbonate solution in the sodium bicarbonate solution storage tank reaches 8-10%, the electrodialysis is stopped, and the sodium bicarbonate solution is transported to the freezing crystallization unit for freezing crystallization, and the freezing temperature is controlled to be 0-10° C. The crystallization mother liquor after separating the sodium bicarbonate crystals is first used to assist the electrodialysis module in cooling, and then a part of it is used for washing the mirabilite tailings after adsorption, and the other part is refluxed into the sodium bicarbonate solution storage tank.

9. The electrodialysis method for carbon fixation and alkali production using the filtrate from washing of mirabilite tailings according to claim 1, characterized in that: In step S5, the ammonium sulfate crystals are produced in a batch mode. When the concentration of the ammonium sulfate solution in the ammonium sulfate solution storage tank reaches 14-18%, the electrodialysis is stopped, and the ammonium sulfate solution is transported to the evaporation crystallization unit for evaporation crystallization. The evaporation temperature is controlled to be 70-90° C., and a part of the condensate produced by the evaporation crystallization is used for washing the mirabilite tailings after adsorption, and the other part is refluxed to the ammonium sulfate solution storage tank.

10. An electrodialysis system for carbon fixation and alkali production using water filtrate of mirabilite tailings, characterized in that: include Sodium sulfate raw material unit, used to crush, three-stage countercurrent water washing, filtration, adsorption treatment of mirabilite tailings and then add them into the sodium sulfate solution storage tank; The ammonium bicarbonate raw material unit is used to pass carbon dioxide into the bottom of the absorption tower to countercurrently contact with ammonia water entering from the upper part of the absorption tower to synthesize ammonium bicarbonate, and then add it into the ammonium bicarbonate solution storage tank; The electrodialysis device is connected to the sodium sulfate solution storage tank and the ammonium bicarbonate solution storage tank respectively, and is used to perform electrodialysis double decomposition on the sodium sulfate solution and the ammonium bicarbonate solution to obtain the sodium bicarbonate solution and the ammonium sulfate solution in the corresponding sodium bicarbonate compartment and the ammonium sulfate compartment respectively; a sodium bicarbonate product unit, comprising a sodium bicarbonate solution storage tank connected to the sodium bicarbonate compartment outlet and a freezing crystallization unit connected to the sodium bicarbonate solution storage tank outlet; An ammonium sulfate product unit, comprising an ammonium sulfate solution storage tank connected to the outlet of the ammonium sulfate compartment and an evaporation crystallization unit connected to the outlet of the ammonium sulfate solution storage tank; The electrodialysis system for producing alkali by carbon fixation using water-washed filtrate of mirabilite tailings is used to execute the electrodialysis method for producing alkali by carbon fixation using water-washed filtrate of mirabilite tailings as claimed in any one of claims 1 to 9.

11. The electrodialysis system for carbon fixation and alkali production using water filtrate of mirabilite tailings according to claim 10, characterized in that: The electrodialysis device comprises an anode, a cathode and a plurality of electrodialysis modules arranged between the anode and the cathode; each electrodialysis module comprises a sodium sulfate compartment, a sodium bicarbonate compartment, an ammonium bicarbonate compartment and an ammonium sulfate compartment; the sodium bicarbonate compartment and the ammonium sulfate compartment are respectively arranged on both sides of the ammonium bicarbonate compartment, and a sodium sulfate compartment is respectively arranged on the outside of the ammonium sulfate compartment and the sodium bicarbonate compartment; a cation membrane is arranged between the sodium sulfate compartment and the sodium bicarbonate compartment, a cathode membrane is arranged between the sodium sulfate compartment and the ammonium sulfate compartment, a cathode membrane is arranged between the sodium bicarbonate compartment and the ammonium bicarbonate compartment, and a cation membrane is arranged between the ammonium bicarbonate compartment and the ammonium sulfate compartment.

12. The electrodialysis system for carbon fixation and alkali production using water filtrate of mirabilite tailings according to claim 11, characterized in that: The sodium sulfate solution storage tank is connected to the inlet of the sodium sulfate compartment through a pump, and the sodium sulfate compartment outlet is connected to the inlet of the sodium sulfate solution storage tank; The ammonium bicarbonate solution storage tank is connected to the inlet of the ammonium bicarbonate compartment via a pump, and the outlet of the ammonium bicarbonate compartment is connected to the inlet of the ammonium bicarbonate solution storage tank; The sodium bicarbonate solution storage tank is connected to the inlet of the sodium bicarbonate compartment through a pump, and the mother liquor outlet of the cooling crystallization unit is connected to the sodium bicarbonate solution storage tank; The ammonium sulfate solution storage tank is connected to the inlet of the ammonium sulfate compartment through a pump, and the condensate outlet of the evaporation crystallization unit is connected to the ammonium sulfate solution storage tank.

13. The electrodialysis system for carbon fixation and alkali production using water filtrate of mirabilite tailings according to claim 11, characterized in that: The anode and cathode electrodes of the electrodialysis device are iridium-tantalum coated titanium electrodes.

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