Saline liquid phase separation system, aluminum electrolysis cell overhaul slag treatment system and method

Abstract

The present invention relates to the field of metallurgical production environmental protection equipment, and more particularly to a salt-containing liquid phase separation system and an aluminum electrolytic cell overhaul slag treatment system and method. The system and method are used for treating the salt-containing liquid phase in the aluminum electrolytic cell overhaul slag treatment system, comprising: a clarifier connected to a filter press used for solid-liquid separation in the aluminum electrolytic cell overhaul slag treatment system, the clarifier being used to clarify the salt-containing liquid phase discharged from the filter press; and an electrodialyzer connected to the clarifier for electrodialysis of the salt-containing liquid phase, the electrodialyzer outlet pipeline comprising a concentrated brine pipeline and a dilute brine pipeline; the concentrated brine pipeline being connected to a concentrated brine storage tank for storing the incoming concentrated brine; and the dilute brine pipeline being connected to a reverse osmosis device for reverse osmosis of the incoming dilute brine and delivering it to a desalted water tank for storing new water required for solid-liquid separation in the aluminum electrolytic cell overhaul slag treatment system. The equipment of the present invention has a simple structure, a novel and reasonable design, energy conservation and emission reduction, and achieves resource utilization, thus having strong promotion and application value.

Description

Technical Field

[0001] The present invention relates to the field of metallurgical production environmental protection equipment, and in particular to a salt-containing liquid phase separation system and an aluminum electrolytic cell overhaul slag treatment system. Background Art

[0002] Aluminum cell overhaul slag is the inner lining removed after a damaged cell. It is listed as a hazardous waste due to the presence of fluorine and cyanide. Existing overhaul slag treatment processes include pyrolysis and wet treatment. Pyrolysis has been limited due to its high energy consumption, while wet treatment is currently the mainstream technology for overhaul slag treatment. The wet treatment process involves adding oxidants to the overhaul slag to decompose and detoxify the cyanide ions. Ca2+ / Mg2+ / Al3+ are then added to form the corresponding fluoride salt precipitation for detoxification. This method is highly efficient and offers stable detoxification results, earning industry recognition. During the wet treatment process, while precipitating and removing the fluorine ions, soluble sodium salts, typically sodium chloride, are generated. With repeated detoxification reactions, the concentration of sodium chloride in the circulating water increases. The attached liquid remaining in the tailings after solid-liquid separation also introduces a high level of soluble salts. This high soluble salt content significantly complicates the reuse of the tailings. Simply washing with water generates large amounts of brine, which not only wastes water resources but also poses a new emission problem. Summary of the Invention

[0003] To this end, the present invention provides a salt-containing liquid phase separation system and an aluminum electrolytic cell overhaul slag treatment system, which have a simple structure, a novel and reasonable design, and can save energy and reduce emissions, thereby achieving the purpose of resource utilization.

[0004] According to the design scheme provided by the present invention, a salt-containing liquid phase separation system is used for treating the salt-containing liquid phase of an aluminum electrolytic cell overhaul slag treatment system, comprising: a clarifier connected to a filter press used for solid-liquid separation in the aluminum electrolytic cell overhaul slag treatment system, the clarifier being used to clarify the salt-containing liquid phase discharged from the filter press; and an electrodialyzer connected to the clarifier for electrodialysis treatment of the salt-containing liquid phase, the electrodialyzer outlet pipeline comprising a concentrated brine pipeline and a dilute brine pipeline; the concentrated brine pipeline is connected to a concentrated brine storage tank to store the inflowing concentrated brine; the dilute brine pipeline is connected to a reverse osmosis device to reverse osmosis the inflowing dilute brine and send it to a desalted water tank for storing new water required for solid-liquid separation in the aluminum electrolytic cell overhaul slag treatment system.

[0005] As the salt-containing liquid phase separation system of the present invention, a filtrate tank is further provided between the clarification tank and the electrodialyzer; an overflow port is provided on the clarification tank, and the clear liquid after clarification treatment flows out from the overflow port into the filtrate tank, and the liquid in the filtrate tank is pumped to the electrodialyzer for electrodialysis treatment.

[0006] As the salt-containing liquid phase separation system of the present invention, further, the concentrated brine storage tank is also connected to an evaporator for salt recovery, and the condensate outlet end of the evaporator is connected to a desalted water tank for storing new water required for solid-liquid separation of the aluminum electrolytic cell overhaul slag treatment system through a pipeline.

[0007] As the salt-containing liquid phase separation system of the present invention, further, the desalted water tank is also connected to a circulating liquid tank for storing dissolving reagents and / or new water required for leaching reaction in the aluminum electrolytic cell overhaul slag treatment system.

[0008] Furthermore, the present invention also provides an aluminum electrolytic cell overhaul slag treatment system for resource utilization of aluminum electrolytic cell overhaul slag, comprising: a powder making device for crushing the overhaul slag; a reaction chamber connected to the powder making equipment for harmlessly treating the powder output by the powder making equipment, the reaction chamber comprising a reaction chamber one for cyanide removal reaction and a reaction chamber two for fluorine removal reaction; a reaction chamber three connected to the reaction chamber one or the reaction chamber two for buffering treatment, the reaction chamber three being connected to a filter press for solid-liquid separation; and the above-mentioned salt-containing liquid phase separation system, the salt-containing liquid phase separation system being connected to the filter press for separating and treating the salt-containing liquid phase to obtain circulating water for the overhaul slag resource utilization system.

[0009] As the aluminum electrolytic cell overhaul slag treatment system of the present invention, further, the powder making equipment includes a box crusher connected to the ore feeding bin, a block bin connected to the box crusher, a ball mill connected to the block bin, and a powder bin connected to the ball mill.

[0010] As the aluminum electrolytic cell overhaul slag treatment system of the present invention, a powder material metering bin is further provided between the powder material bin and the reaction bin.

[0011] Furthermore, the present invention also provides a method for treating slag from an aluminum electrolytic cell overhaul, comprising the following contents:

[0012] a. First, crush and pulverize the aluminum electrolytic cell overhaul slag;

[0013] b. The obtained overhaul slag powder is transported to the first and second reaction chambers in order to carry out cyanide removal and fluorine removal reactions to obtain harmless overhaul slag materials;

[0014] c. Send the harmlessly treated overhaul slag material into the reaction chamber 3 for buffering;

[0015] d. The buffered overhaul slag material is sent to a filter press for solid-liquid separation. The filter cake obtained after separation is washed with salt-free water to obtain a salt-free solid phase and a salt-containing liquid phase;

[0016] e. The obtained salt-free solid phase is used for building materials; the obtained salt-containing liquid phase is subjected to salt recovery using the salt-containing liquid phase separation system according to claim 1 to obtain salt-free water, which is then transported as new water to the cyanide removal, fluoride removal and leaching reaction sections for recycling.

[0017] As the aluminum electrolysis cell overhaul slag treatment method of the present invention, further, the aluminum electrolysis cell overhaul slag mineral material is crushed to prepare the overhaul slag powder with a size of 100-200 μm.

[0018] As the aluminum electrolytic cell overhaul slag treatment method of the present invention, further, in the salt recovery process, the salt-containing water in transportation is subjected to electrodialysis to obtain concentrated brine with a concentration of 150-250 g / L and dilute brine with a concentration of 10-12 g / L; the concentrated brine is recovered from the salt by an evaporator, and the condensed water generated during the recovery process is transported to a desalted water tank for storing new water in the water washing section; the dilute brine is obtained by a reverse osmosis device and transported to the desalted water tank.

[0019] Beneficial effects of the present invention:

[0020] The present invention is novel and reasonable in design. After the overhaul slag obtained by wet treatment is washed with water, the solid phase (overhaul slag tailings) after washing away the soluble salt can be widely used as building materials. The liquid phase can be concentrated by electrodialysis using the salt-containing liquid phase separation system of the present invention to obtain concentrated brine and dilute brine respectively. The concentrated brine enters the evaporator for evaporation to obtain sodium chloride, and the condensed water can be re-entered into the system for use; the dilute brine is further desalted by reverse osmosis to obtain desalted water, which is returned to the washing section to wash the overhaul slag after wet treatment, and is recycled, thereby saving energy and reducing emissions and achieving the purpose of resource utilization. The invention has strong promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the salt-containing liquid phase separation system in the embodiment;

[0022] Figure 2 Schematic diagram of the structure of the slag treatment system for overhaul of aluminum electrolytic cells in the embodiment.

[0023] In the figure, reference numeral 100 represents a filtrate tank, reference numeral 101 represents an electrodialyzer and a reverse osmosis device, reference numeral 102 represents a desalted water tank, reference numeral 103 represents a circulating liquid tank, reference numeral 104 represents a concentrated brine tank, reference numeral 105 represents a salt separator, reference numeral 106 represents a salt precipitator, and reference numeral 107 represents a separator; reference numeral 200 represents a feed silo, reference numeral 201 represents a sealed feeder, reference numeral 202 represents a box crusher, reference numeral 203 represents an iron remover, reference numeral 204 represents a belt conveyor, and reference numeral 205 represents a separator. , 2052, 2053 represent bucket elevators, number 206 represents a block silo, number 207 represents a vibrating feeder, number 208 represents a ball mill, number 209 represents a powder silo, number 2101, 2102 represent screw conveyors, number 211 represents a powder metering silo, number 2121 represents reaction silo one, number 2122 represents reaction silo two, number 2123 represents reaction silo three, number 2131 represents reagent silo A, number 2132 represents reagent silo B, and number 214 represents a clarifier. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and technical solutions, and the implementation of the present invention will be described in detail through preferred embodiments, but the implementation of the present invention is not limited thereto.

[0025] The slag from the overhaul of aluminum electrolytic cells contains cathode carbon blocks, refractory bricks, paste, insulation bricks, refractory powder, refractory mortar, insulation boards, infiltrated metals and electrolytes, as well as a small amount of aluminum nitride and cyanide salts. During the wet treatment of the slag from the overhaul of aluminum electrolytic cells, while the F ions are precipitated and removed, a soluble sodium salt, usually sodium chloride, is generated. As the detoxification reaction is repeated, the concentration of sodium chloride in the circulating water becomes higher and higher. For this reason, in the embodiment of the present invention, during the harmless and resourceful treatment of the slag from the overhaul of aluminum electrolytic cells, see Figure 1 and 2 As shown, a system for treating overhaul slag of an aluminum electrolytic cell is provided for resource utilization of overhaul slag of an aluminum electrolytic cell, comprising: a powder-making device for crushing the overhaul slag; a reaction chamber connected to the powder-making device for harmlessly treating the powder output by the powder-making device, the reaction chamber comprising a reaction chamber 1 2121 for cyanide removal reaction and a reaction chamber 1 2122 for fluorine removal reaction; a reaction chamber 3 2123 connected to the reaction chamber 1 2121 or the reaction chamber 2 2122 for buffering treatment, the reaction chamber 3 2123 being connected to a filter press for solid-liquid separation; and a salt-containing liquid phase separation system, the salt-containing liquid phase separation system being connected to the filter press for separating the salt-containing liquid phase to obtain circulating water for the overhaul slag resource utilization system.

[0026] Among them, salt-containing liquid phase separation system, see Figure 1As shown, it includes: a pulverizing device for crushing overhaul slag; a reaction chamber connected to the pulverizing device for harmlessly treating the powder output by the pulverizing device, the reaction chamber comprising a reaction chamber 1 2121 for decyanation reaction and a reaction chamber 2 2122 for defluorination reaction; a reaction chamber 3 2123 connected to reaction chamber 1 2121 or reaction chamber 2 2122 for buffering treatment, reaction chamber 3 2123 being connected to a filter press for solid-liquid separation; and the aforementioned salt-containing liquid phase separation system, which is connected to the filter press for separating the salt-containing liquid phase to obtain circulating water for the overhaul slag resource utilization system. Chemical chamber A and chemical chamber B can be used to store decyanation agent and defluorination agent, or defluorination agent and decyanation agent, respectively, so that the corresponding agents can be added to reaction chamber 1 2121 and reaction chamber 2 2122 to carry out the corresponding reactions. After the overhaul slag obtained by wet treatment is washed with water, the solid phase (overhaul slag tailings) after washing away the soluble salt can be widely used as building materials. The liquid phase can be concentrated by electrodialysis using the salt-containing liquid phase separation system of the present invention to obtain concentrated brine and dilute brine respectively. The concentrated brine enters the evaporator for evaporation to obtain sodium chloride, and the condensed water can be re-entered into the system for use; the dilute brine is further desalted by reverse osmosis to obtain desalted water, which is returned to the washing section to wash the overhaul slag after wet treatment, and is recycled to save energy and reduce emissions, thereby achieving the purpose of resource utilization, and has strong promotion and application value.

[0027] As the salt-containing liquid phase separation system in the embodiment of the present invention, a filtrate tank 100 is further provided between the clarification tank 214 and the electrodialyzer; an overflow port is provided on the clarification tank 214, and the clear liquid after clarification flows out from the overflow port into the filtrate tank 100, and the liquid in the filtrate tank 100 is pumped to the electrodialyzer for electrodialysis treatment. Figure 2 As shown, the clear liquid in the clarification tank 214 continuously flows out of the overflow port into the filtrate tank 100; the turbid liquid at the bottom can be regularly or irregularly returned to the reaction chamber 3 2123. After electrodialysis, the liquid in the filtrate tank 100 can be converted into a concentrated brine with a concentration of 200g / L and a dilute brine with a concentration of 10-12g / L.

[0028] As the salt-containing liquid phase separation system in an embodiment of the present invention, the concentrated brine storage tank is further connected to an evaporator for salt recovery, and the condensed water outlet of the evaporator is connected to the desalted water tank 102 for storing new water required for solid-liquid separation of the aluminum electrolytic cell overhaul slag treatment system through a pipeline.

[0029] As a salt-containing liquid phase separation system in an embodiment of the present invention, the desalted water tank 102 is further connected to a circulating liquid tank 103 for storing the dissolving agent and / or the new water required for the leaching reaction in the aluminum electrolytic cell overhaul slag treatment system. The liquid stored in the circulating liquid tank 103 can also be pumped to the water washing section for washing the filter cake. Figure 1As shown, the evaporator can also be connected to a separator 107 for secondary evaporation separation; the condensed water outlet of the separator 107 is connected to the desalted water tank 102 through a pipeline, and its concentrated liquid outlet is connected to the salt precipitator 106 through a pipeline; the salt precipitator 106 is connected to a salt separator 105 for brine separation, and the liquid outlet end of the salt separator is connected to the circulating liquid tank 103.

[0030] As an aluminum electrolytic cell overhaul slag treatment system in an embodiment of the present invention, the pulverizing equipment further includes a box crusher 202 connected to a feed silo 200, a lump silo 206 connected to the box crusher 202, a ball mill 208 connected to the lump silo 206, and a powder silo 209 connected to the ball mill 208. By crushing and pulverizing the aluminum electrolytic cell overhaul slag, a powder of 100-200 μm can be obtained, which facilitates subsequent immersion reaction and improves the harmless treatment effect.

[0031] As the aluminum electrolytic cell overhaul slag treatment system in the embodiment of the present invention, a powder metering bin 211 is further provided between the powder bin 209 and the reaction bin to facilitate immersion reaction treatment according to the reagent ratio and improve the reaction effect.

[0032] See also Figure 1 As shown, reaction chamber 1 2121, reaction chamber 2 2122, and reaction chamber 3 2123 can be equipped with stirring devices to stir the materials in the reaction chambers, thereby improving the slurrying, leaching, or reaction effects. Slurry pumps, water pumps, or other pumping and / or water extraction devices can be installed in each pipeline connection to improve the efficiency of transportation, water injection, or slurry transfer. The raw materials are sent to the feeding bin 200, and then transported to the box crusher 202 through the sealed feeder 201. The iron blocks in the raw materials are further removed by the iron remover 203, and then sent to the block bin 206 through the belt conveyor 204 and the bucket elevator. A vibrating feeder 207 is provided at the lower part of the block bin 206 to facilitate the delivery of the block materials in the block bin 206 to the ball mill 208 for powder making operation. During the powder making operation, the coarse particles are screened out by screening, and the fine materials can be further sent to the powder bin 209 through the bucket elevator. The powder in the powder bin 209 can be further sent to the powder metering bin 211 through the screw conveyor and the bucket elevator, thereby forming a powder making device and its transportation line, and delivering the reaction materials to be leached to the reaction bin.

[0033] In the present invention, see Figure 1As shown, the overhaul slag is crushed and pulverized to produce a 100-200 μm powder. The powder then enters a reaction chamber and reacts with a cyanide remover and a fluorine remover. The resulting harmless slag is then buffered in another reaction chamber. A circulating liquid tank 103 provides water for melting the reagents and for the leaching reaction. The reacted material enters a filter press from reaction chamber 3 for solid-liquid separation. The filter cake from the initial solid-liquid separation is washed in the filter press with salt-free water to produce a salt-free solid phase and a salt-containing liquid phase. The solid phase can be used as a building material; the salt-containing liquid phase enters clarification tank 214 for further clarification. The clear liquid continuously flows out of the overflow port into the filtrate storage tank; the turbid liquid at the bottom is periodically or irregularly returned to the other reaction chamber. Electrodialysis of the liquid in filtrate tank 100 produces a concentrated brine with a concentration of 200 g / L and a dilute brine with a concentration of 10-12 g / L. Concentrated brine enters the brine storage tank and is pumped into the evaporator, producing salt and condensed water. The condensed water enters the desalted water tank 102. The brine undergoes reverse osmosis to produce desalted water, which enters the desalted water tank 102. The desalted water can be used as fresh water to replenish the circulating liquid tank 103 or rinse the salt from the filter cake. In this invention, the brine can be separated through "electrodialysis + reverse osmosis" to produce salt-free water that can be recycled repeatedly, significantly reducing water consumption for salt washing and achieving water recycling. This significantly reduces water consumption for salt washing, reduces energy consumption, and enhances corporate image and economic benefits.

[0034] Furthermore, an embodiment of the present invention also provides a method for treating overhaul slag of an aluminum electrolytic cell, comprising the following contents: conveying the crushed overhaul slag powder to a reaction chamber, performing decyanation, defluorination and leaching reaction on the overhaul slag powder by adding dissolving agent water and leaching reaction water in the reaction chamber, and obtaining harmless overhaul slag material; conveying the treated material to a filter press for solid-liquid separation and washing with salt-free water to obtain a salt-free solid phase and a salt-containing liquid phase, recovering salt from the salt-containing liquid phase by utilizing the above-mentioned salt-containing liquid phase separation system to obtain salt-free water, and conveying the salt-free water as new water to the decyanation, defluorination and leaching reaction section for recycling.

[0035] In the wet treatment of overhaul slag, after the overhaul slag is ground, it is washed in water and then sequentially leached with water and alkali, etc., to leach all the fluoride and cyanide therein into the solution, and then filtered. In the embodiment of the present invention, for decyanation, defluorination and leaching reaction, the overhaul slag powder can be stirred with water in a certain mass ratio to obtain a leaching slurry, and the soluble fluoride and cyanide are fully dissolved; and in one of the two reaction chambers, a decyanation agent is added, and after stirring and reacting for a period of time, the cyanide therein is removed. Similarly, in the other reaction chamber, a defluorination agent is added, and after stirring and reacting for a period of time, the fluoride therein is removed. The amount of defluorination agent and decyanation agent added refers to the content of cyanide and fluoride in the slurry after the reaction. The slurry after the reaction is sent to a filter press for solid-liquid separation. The filter cake after the preliminary solid-liquid separation is washed with salt-free water on the filter press to obtain a salt-free solid phase and a salt-containing liquid phase that can be used as a building material. For the salt-containing liquid phase, the salt is recovered by utilizing the salt-containing liquid phase separation system in the above embodiment, and the obtained salt-free water is transported to the water washing section as new water for recycling, which is environmentally friendly and energy-saving and meets the requirements of compliance.

[0036] Aluminum electrolytic cell overhaul slag can be crushed into 100-200μm overhaul slag powder to facilitate leaching and solvent reactions. The cyanide remover in the solvent can be one or more of sodium chlorate, bleaching powder, hydrogen peroxide, bleaching powder concentrate, or chlorine dioxide; the fluoride remover can be one or more of calcium chloride, aluminum chloride, magnesium chloride, calcium hydroxide, or calcium oxide.

[0037] Furthermore, in the salt recovery process, electrodialysis is performed on the salt water in transportation to obtain concentrated brine with a concentration of 150-250 g / L and dilute brine with a concentration of 10-12 g / L; for the concentrated brine, an evaporator is used to recover its salt, and the condensed water generated during the recovery process is transported to a desalted water tank for storing new water in the water washing section; for the dilute brine, a reverse osmosis device is used to obtain desalted water, and the desalted water is transported to the desalted water tank, thereby realizing the recycling of water energy, saving energy and reducing emissions, and achieving the purpose of resource utilization, which has strong promotion and application value.

[0038] The present invention is not limited to the above specific embodiments, and those skilled in the art may make various changes accordingly. However, any changes that are equivalent or similar to the present invention should be included in the scope of the claims of the present invention.

[0039] The term "and / or" in this document indicates that three relationships can exist. For example, A and / or B can represent: A alone, A and B together, or B alone. Additionally, the character " / " in this document generally indicates that the preceding and following relationships are in an "or" relationship.

[0040] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by persons of ordinary skill in the field to which the invention belongs. The terms "first", "second" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, terms such as "a" or "an" do not necessarily indicate a quantity limitation. Terms such as "include" or "comprising" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Terms such as "upper", "lower", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0041] The exemplary embodiments of the present invention are described in detail above with reference to preferred embodiments. However, it will be understood by those skilled in the art that, without departing from the concept of the present invention, various modifications and variations can be made to the above-mentioned specific embodiments, and various combinations of the various technical features and structures proposed in the present invention can be made without exceeding the scope of protection of the present invention, which is determined by the appended claims. The foregoing description of the specific exemplary embodiments of the present invention is not intended to limit the present invention to the precise form disclosed, and it is obvious that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can implement and utilize the various exemplary embodiments of the present invention and various different options and changes. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A method for treating slag from an aluminum electrolytic cell overhaul, characterized in that: It is implemented based on an aluminum electrolytic cell overhaul slag treatment system, and the aluminum electrolytic cell overhaul slag treatment system includes: a powder making device for crushing the overhaul slag; a reaction chamber connected to the powder making device for harmless treatment of the powder output by the powder making device, the reaction chamber including a reaction chamber 1 for cyanide removal reaction and a reaction chamber 2 for fluorine removal reaction; a reaction chamber 3 connected to the reaction chamber 1 or the reaction chamber 2 for buffering treatment, the reaction chamber 3 being connected to a filter press for solid-liquid separation; and a salt-containing liquid phase separation system, the salt-containing liquid phase separation system being connected to the filter press for separating and treating the salt-containing liquid phase to obtain circulating water for the overhaul slag resource utilization system; The salt-containing liquid phase separation system comprises: a clarifier connected to a filter press for solid-liquid separation of an aluminum electrolytic cell overhaul slag treatment system, the clarifier being used to clarify the salt-containing liquid phase discharged from the filter press; and an electrodialyzer connected to the clarifier for electrodialysis of the salt-containing liquid phase, the electrodialyzer outlet pipeline comprising a concentrated brine pipeline and a dilute brine pipeline; the concentrated brine pipeline is connected to a concentrated brine storage tank for storing the inflowing concentrated brine; the dilute brine pipeline is connected to a reverse osmosis device for reverse osmosis of the inflowing dilute brine and sent to a desalted water tank for storing new water required for solid-liquid separation of the aluminum electrolytic cell overhaul slag treatment system; the concentrated brine storage tank is also connected to an evaporator for salt recovery, and the condensate outlet end of the evaporator is connected to a desalted water tank for storing new water required for solid-liquid separation of the aluminum electrolytic cell overhaul slag treatment system through a pipeline; the desalted water tank is also connected to a circulating liquid tank for storing new water required for dissolving reagents and / or leaching reactions of the aluminum electrolytic cell overhaul slag treatment system; The slag treatment process for aluminum electrolytic cell overhaul includes the following steps: a. First, crush and pulverize the aluminum electrolytic cell overhaul slag; b. The obtained overhaul slag powder is transported to the first and second reaction chambers in order to carry out cyanide removal and fluorine removal reactions to obtain harmless overhaul slag materials; c. Send the harmlessly treated overhaul slag material into the reaction chamber 3 for buffering; d. The buffered overhaul slag material is sent to a filter press for solid-liquid separation. The filter cake obtained after separation is washed with salt-free water to obtain a salt-free solid phase and a salt-containing liquid phase; e. The obtained salt-free solid phase is used for building materials; the obtained salt-containing liquid phase is subjected to salt recovery by a salt-containing liquid phase separation system to obtain salt-free water, which is transported as new water to the cyanide removal, defluorination and leaching reaction sections for recycling. In the salt recovery process, the salt-containing water in the transport is subjected to electrodialysis to obtain concentrated brine with a concentration of 150-250 g / L and dilute brine with a concentration of 10-12 g / L; the obtained concentrated brine is subjected to salt recovery by an evaporator to obtain salt and condensed water, and the obtained condensed water is transported to a desalted water tank for storing new water in the water washing section; the obtained dilute brine is used to obtain desalted water by a reverse osmosis device, and the desalted water is transported to the desalted water tank.

2. The aluminum electrolysis cell overhaul slag treatment method according to claim 1, characterized in that: The particle size of the powder obtained in step a is 100 to 200 μm.

3. The method for treating slag from overhaul of aluminum electrolysis cell according to claim 1, characterized in that: The powder making equipment comprises a box crusher connected to a feed bin, a block bin connected to the box crusher, a ball mill connected to the block bin, and a powder bin connected to the ball mill.

4. The aluminum electrolysis cell overhaul slag treatment method according to claim 3, characterized in that: A powder metering bin is also provided between the powder bin and the reaction bin.

5. The aluminum electrolysis cell overhaul slag treatment method according to claim 1, characterized in that: A filtrate tank is also provided between the clarification tank and the electrodialyzer; an overflow port is provided on the clarification tank, and the clear liquid after clarification flows out from the overflow port into the filtrate tank, and the liquid in the filtrate tank is pumped to the electrodialyzer for electrodialysis treatment.

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