A red mud treatment method based on gravity energy storage

Abstract

This invention belongs to the field of gravity energy storage and solid waste treatment technology, specifically relating to a red mud treatment method based on gravity energy storage. The method includes the following steps: preparation of solid waste heavy materials: red mud is dried, ground, mixed, granulated, and then placed into a porous container to obtain red mud solid waste heavy materials; static curing: during stacking, dealkali reaction solution is sprayed for curing; dynamic curing: during the energy storage and / or power generation transportation of the gravity energy storage system, dynamic curing is achieved through ventilation, vibration, and position changes during transportation; curing cycle: static and dynamic curing are repeated; periodic monitoring, and when the red mud solid waste reaches the predetermined treatment standard, it is discharged. This invention deeply couples red mud solid waste treatment with gravity energy storage, shortening the treatment cycle, reducing costs, and achieving the synergistic operation of red mud harmlessness, resource utilization, and efficient energy storage.

Description

Technical Field

[0001] This invention relates to the field of gravity energy storage and solid waste treatment technology, specifically a red mud treatment method based on gravity energy storage. Background Technology

[0002] Red mud is a large quantity of highly alkaline solid waste generated from the alumina industry. It contains soluble alkali (mainly Na⁺) and various heavy metals (Cu, Zn, Cr, Ni, As, Pb, Cd, etc.). Long-term storage can lead to migration through leaching, causing serious pollution to surrounding soil and groundwater. Traditional red mud solid waste treatment methods mainly include water washing for alkali removal, acid neutralization, calcium ion replacement, microbial methods, and solidification / stabilization technologies. However, existing technologies generally face the following technical problems: 1) They require dedicated treatment sites and equipment, occupying significant land resources and infrastructure investment; 2) The treatment process consumes large amounts of water resources or chemical agents, creating a risk of secondary pollution; 3) The treatment cycle is long, and the treatment cost is high; 4) It is difficult to achieve large-scale, continuous disposal of red mud.

[0003] Gravity energy storage technology is a rapidly developing large-scale energy storage technology in recent years. Its basic principle is to utilize surplus electricity generated from new energy sources to enhance the potential energy of heavy objects, which are then lowered during peak electricity demand periods to generate electricity using gravity. Gravity energy storage systems typically include an elevated storage yard, a lower storage yard, a transportation system for circulating the heavy objects between the two yards, and electric generator sets. Existing gravity energy storage systems use standardized gravity blocks, usually made of concrete or solid waste-based composite materials, which are circulated between the upper and lower storage yards to store and release electrical energy. However, existing gravity energy storage systems only utilize the mechanical properties of the gravity blocks (mass, density, strength, etc.) without functionally expanding their material composition and manufacturing process. Furthermore, the vibrations and ventilation conditions generated during transport are not effectively utilized.

[0004] In existing technologies, solid waste treatment such as red mud and gravity energy storage are two independent systems that cannot generate synergistic benefits. Solid waste treatment lacks continuous and efficient dynamic response conditions, while the heavy objects used in traditional gravity energy storage need to be customized, which is costly. At present, there is no technical solution that integrates the solid waste treatment process of red mud with the gravity energy storage transportation process, which is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, the present invention aims to provide a red mud treatment method based on gravity energy storage, the method comprising the following steps: A red mud treatment method based on gravity energy storage includes the following steps: Preparation of solid waste heavy materials: After drying and crushing red mud, the red mud powder is mixed with cementitious materials and granulated to obtain red mud-based particles; the red mud-based particles are loaded into a porous loading container to form red mud solid waste heavy materials; Static curing: The red mud solid waste heavy material is transported to the high-level stockpile and / or low-level stockpile of the gravity energy storage system, and stacked in the stockpile area. During the stockpile period, the red mud solid waste heavy material is sprayed with the reaction liquid for dealkalization. Dynamic maintenance: During the energy storage and / or power generation transportation of the gravity energy storage system, the red mud solid waste heavy materials in the stockpile area are loaded onto the transport train. The transport train is used to circulate between the high-level stockpile and the low-level stockpile of the gravity energy storage system for loading and unloading. The position of the red mud solid waste heavy materials is moved, and the vibration during transportation and the ventilation of the loading container holes are used to dynamically maintain the red mud solid waste heavy materials. Maintenance cycle: Repeated static and dynamic maintenance, so that the red mud solid waste is alternately stacked and transported between different stockpiles. During stacking, reaction liquid is sprayed, and vibration and ventilation are used during transportation. Regular monitoring: The compressive strength of the red mud solid waste particles within the loading container, and the Na... + The concentration and pH value of the leachate are randomly sampled daily, and the treatment status of the red mud solid waste is recorded until the red mud solid waste reaches the predetermined treatment standard. Discharge: The red mud that has reached the predetermined treatment standard is removed from the loading container from the system, and new red mud to be treated is put into the solid waste heavy material preparation process.

[0006] Preferably, in the preparation of solid waste heavy materials, the red mud is dried to a moisture content of 20% to 30%; the cementing material is a hydraulic cementitious powder, with 80 to 90 parts of red mud powder and 10 to 20 parts of hydraulic cementitious powder by weight; the hydraulic cementitious powder is one or more of silicate series cement, alkali-activated slag, lime, and fiber materials.

[0007] Preferably, in the preparation of solid waste heavy materials, an alkali activator and a water-reducing agent are added, and then an appropriate amount of water is added and mixed into a uniform dry thick paste; the amount of alkali activator added is 3% to 8% of the total mass of the powder raw materials, the amount of water-reducing agent added is 0.5% to 1% of the total mass of the powder raw materials, and the amount of mixing water is 15% to 20% of the mass of the solid powder.

[0008] Preferably, the dry, thick paste is made into red mud-based solid waste granules, left to stand naturally to allow a preliminary gel film to form on the surface of the granules, and then loaded into a porous loading container.

[0009] Red mud itself has high density potential. The diameter of red mud particles is generally 0.088-0.25 mm, the density is 2700-2900 kg / m³, and the bulk density is 800-1000 kg / m³. The compressive strength of red mud particles prepared from the above components after curing can reach 15-22 MPa, and the Na⁺ leaching concentration is significantly reduced from 2.01 g / L in the original red mud residue to 0.43 g / L.

[0010] Preferably, in the preparation of solid waste heavy materials, the porous loading container has a rectangular structure, is made of high-strength material, and has liquid-permeable and air-permeable holes on the top, bottom and side walls, with an opening rate of 40% to 60%. It is equipped with positioning interfaces and lifting connectors around the perimeter, an openable cover plate on the top, and stacking positioning posts and positioning grooves at the four corners.

[0011] Preferably, in the preparation of solid waste heavy materials, during the process of loading red mud-based particles into a porous loading container, vibration compression filling is performed with a vibration frequency of 50-150 Hz and an amplitude of 0.5-2 mm; after vibration compression filling, the bulk density of the red mud-based particles is 1.6-2.0 g / cm³.

[0012] After vibration compression filling, the bulk density of red mud-based particles increased from 1.2–1.6 g / cm³ to 1.6–2.0 g / cm³, making the mass of red mud-based gravity blocks close to that of concrete gravity blocks of the same volume, thus meeting the energy density requirements of gravity energy storage systems.

[0013] Preferably, in static curing, the reaction solution includes an alkali activator and a dealkali solution; the alkali activator is sprayed when the red mud solid waste is first piled up, and the dealkali solution is sprayed after the stockpile is changed. Subsequently, as the red mud solid waste is alternately stored between high-level and low-level stockpiles, the reaction solution is sprayed alternately in sequence.

[0014] Preferably, when spraying the alkali activator, the spraying interval is 2-4 hours / time, the single spraying amount is 1-2 L / m², and the stacking time is 24-72 hours; when spraying the dealkali solution, the spraying interval is 1-3 hours / time, the single spraying amount is 1.5-2.5 L / m², and the stacking time is 12-48 hours.

[0015] Preferably, the alkali activator is a water glass solution or a sodium hydroxide solution, wherein the water glass solution has a modulus of 1.0 to 2.0 and a mass concentration of 5% to 15%, and the sodium hydroxide solution has a mass concentration of 5% to 10%; the dealkali solution is water or a dilute acid solution, wherein the pH value of the dilute acid solution is 5 to 6.

[0016] The reaction solution enters the particle layer through the permeable and vented holes at the top of the loading container, rapidly diffusing in the interconnected pore network between particles and uniformly wetting each particle. The OH⁻ ions in the alkali-activated solution react with the active SiO₂ and Al₂O₃ in the red mud particles, promoting the depolymerization and condensation of aluminosilicates to generate a geopolymer gel. This gel forms a cementing bridge at the particle contact points, gradually transforming the loose particle layer into a porous solidified body with a certain overall strength. At the same time, the gel generated by the alkali-activated reaction fills some of the voids between particles, further improving the density and mechanical properties of the energy storage heavy block, while the strong alkalinity of the red mud itself can serve as a synergistic alkali source, promoting the gelation reaction.

[0017] Preferably, during dynamic maintenance, the transport train circulates between the high-level and low-level storage yards of the gravity energy storage system for loading and unloading, and the reaction liquid is sprayed during the unloading and stacking process.

[0018] Preferably, during the unloading and stacking process, the materials are stacked in layers. After stacking one or more layers, the reaction liquid is sprayed once to improve the uniformity of the reaction liquid penetration, allowing the red mud solid waste to fully contact the reaction liquid and react more thoroughly, effectively shortening the harmless treatment cycle.

[0019] During dynamic curing, vibration and ventilation during transportation enable dynamic oxidation. The low-frequency continuous vibration generated during transportation causes relative slippage and micro-displacement of the red mud-based particles, breaking the dense compacted layer formed by static stacking, expanding the wetting interface of the reaction liquid, and avoiding uneven local reactions. At the same time, vibration drives directional convection of alkali and dealkali solutions within the pores, accelerating the migration of soluble Na⁺ and OH⁻ to the outside, significantly improving the dealkali removal rate and uniformity. Furthermore, vibration promotes the redistribution of gelling components, causing the hydration products / geopolymer gel to form a cemented bridge at the particle contact points, improving the overall integrity and compressive strength of the particles.

[0020] Ventilation during transportation accelerates the evaporation of moisture from the particle surface, regulates the humidity of the system, avoids localized over-humidity leading to a decrease in strength, and promotes the stabilization of heavy metals and reduces the leaching of harmful ions in a moderately oxidizing atmosphere. At the same time, it accelerates the reaction between CO2 and alkaline solution, assists in neutralization and alkali reduction, and the airflow keeps the pores between particles unobstructed, ensuring uniform penetration of subsequent spray liquid, forming a virtuous cycle of "ventilation-mass transfer-reaction".

[0021] Vibration opens up structural channels, and ventilation enhances gas-liquid exchange. The coupling of these two processes accelerates the curing, dealkalization, and stabilization reactions simultaneously. Compared to purely static curing, the treatment cycle is shortened by more than 30%, and the uniformity and stability of the product are significantly improved.

[0022] By cyclically loading and unloading the red mud solid waste between the high-level and low-level storage yards of the gravity energy storage system using transport trains, the position of the red mud solid waste is moved, breaking the compacted state of the solid waste stack, so that the reaction liquid can fully contact the red mud solid waste.

[0023] Preferably, in periodic monitoring, the treatment standards are: the compressive strength of the red mud solid waste particles ≥15MPa, the Na⁺ leaching concentration ≤0.43g / L, and the pH value reaches 7~7.5.

[0024] Compared with the prior art, the present invention has the following beneficial effects: (1) Achieving deep synergy between red mud solid waste treatment and gravity energy storage, breaking through the bottleneck of single technology: converting red mud solid waste into gravity energy storage medium not only solves the problems of high cost and large resource consumption of special media (concrete blocks, ore) in traditional gravity energy storage systems, but also overcomes the defects of high energy consumption, long cycle and secondary pollution risk in red mud solid waste treatment; through the synergistic design of "static maintenance + dynamic maintenance", the red mud solid waste treatment process and the energy storage / power generation process are carried out simultaneously, without the need for additional land and energy, which greatly improves the comprehensive utilization efficiency of the system.

[0025] (2) Shorten the treatment cycle of red mud solid waste and improve the stability of treatment effect: Traditional static curing of red mud solid waste has problems such as uneven local reaction and poor ventilation, resulting in long treatment cycle and fluctuating effect; This system realizes natural ventilation of red mud solid waste through the circulation transportation of dynamic curing, and breaks the solid waste stacking and compaction state by moving the position of the transfer device, so that the reaction liquid and red mud solid waste are in full contact. At the same time, the directional spraying in the static curing stage ensures stable reaction conditions. Compared with traditional technology, it can shorten the treatment cycle of red mud solid waste.

[0026] (3) Reduce the cost of energy storage system and optimize energy utilization efficiency: Red mud solid waste is used as an energy storage medium without the need for additional procurement and preparation, which greatly reduces the initial investment cost of gravity energy storage system; when the system is running, it uses the off-peak electricity of the power grid to drive the transport train to store energy, and during peak hours, it drives the power generation by driving the heavy objects to move down, so as to realize the peak shaving and valley filling of the power grid and smooth the fluctuation of new energy power generation; at the same time, the red mud solid waste treatment process does not require additional energy consumption, realizing the energy closed loop of "treating solid waste is energy storage, and energy storage process is treatment", and the cost per kilowatt-hour of the whole life cycle is significantly lower than the combination mode of traditional gravity energy storage and independent solid waste treatment system.

[0027] (4) Significant environmental benefits and realization of solid waste resource recycling: The red mud solid waste is treated in the whole process of pretreatment-curing-standard discharge, which realizes harmlessness and stabilization, avoiding soil and groundwater pollution caused by traditional landfill; the treated red mud solid waste can be used as building aggregate, roadbed material and other resource utilization, which improves the utilization rate of solid waste and reduces resource waste; the spray device equipped in the system acts directionally on the stacking area, combined with the through hole design of the loading container, to ensure efficient utilization of the reaction liquid, without the risk of excessive loss, and can be further improved in terms of environmental protection through the subsequent liquid collection and recycling system, which meets the needs of green development. Attached Figure Description

[0028] Figure 1 A flowchart of a red mud treatment method based on gravity energy storage; Figure 2 This is a schematic diagram of the transportation structure of the gravity energy storage system in the red mud treatment method based on gravity energy storage; Figure 3 This is a schematic diagram of the high-level / low-level stockpile structure in a gravity-based red mud treatment method. Figure 4 This is a side view structural diagram of the high-level / low-level stockpile in a red mud treatment method based on gravity energy storage. Figure 5 This is a top-down structural diagram of the high-level / low-level stockpile in a gravity-based red mud treatment method. Figure 6 This is a schematic diagram of the reaction liquid spraying structure in a red mud treatment method based on gravity energy storage; Figure 7 This is a schematic diagram of the loading container in a red mud treatment method based on gravity energy storage; Figure 8 This is a test diagram of the compressive strength of red mud solid waste particles in Example 1; Figure 9 Na, the leachate from the red mud treatment process in Example 1 + Leaching concentration test chart; Figure 10 This is a pH value test chart of the leachate during the red mud treatment process in Example 1; In the diagram: High-level stockpile A, Low-level stockpile B, Transport track 1, Transport train 2, Stockpile area 3, Transfer device 4, Power generation device 5, Energy storage medium 6, Loading and unloading track 7, Support frame 8, Spray pipe 9, Reagent supply tank 10, Collection tank 11, First collection area 12, Second collection area 13, Collection tray 14, Loading container 15. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] like Figures 1-7 The red mud treatment method based on gravity energy storage, as shown, includes the following steps: Preparation of solid waste heavy materials: After drying and crushing red mud, the red mud powder is mixed with cementitious materials and granulated to obtain red mud-based particles; the red mud-based particles are loaded into a porous loading container 15 to form red mud solid waste heavy materials. Static curing: Transport the heavy red mud solid waste to the high-level stockpile A and / or low-level stockpile B of the gravity energy storage system, stack it in the stockpile area 3, and spray the red mud solid waste with dealkali reaction liquid during the stockpile period. Dynamic maintenance: During the energy storage and / or power generation transportation of the gravity energy storage system, the red mud solid waste heavy materials in the stockpile area 3 are loaded onto the transport train 2. The transport train 2 circulates between the high-level stockpile A and the low-level stockpile B of the gravity energy storage system to carry out the position movement of the red mud solid waste heavy materials, as well as the vibration during transportation and the ventilation of the loading container 15 holes, to carry out dynamic maintenance of the red mud solid waste heavy materials. Maintenance cycle: Repeated static and dynamic maintenance, so that the red mud solid waste is alternately stacked and transported between different stockpiles. During stacking, reaction liquid is sprayed, and vibration and ventilation are used during transportation. Regular monitoring: The compressive strength of the red mud solid waste particles within container 15, and the Na... + The concentration and pH value of the leachate are randomly sampled daily, and the treatment status of the red mud solid waste is recorded until the red mud solid waste reaches the predetermined treatment standard. Discharge: The red mud that has reached the predetermined treatment standard is removed from the loading container 15 and the new red mud to be treated is put into the solid waste heavy material preparation process.

[0031] Gravity energy storage systems are existing publicly available technology; for details, please refer to the applicant's prior invention application CN121158433A, which describes a circulating gravity energy storage and transportation system. Figure 2-7 As shown: it includes, High-level storage yard A and low-level storage yard B have a difference in altitude; Transport track 1 connects the high-level storage yard A and the low-level storage yard B; Transport train 2 can run along transport track 1 between high-level storage yard A and low-level storage yard B; The energy storage medium 6 can be loaded onto the transport train 2 and stacked in the stacking area 3 of the high-level stacking yard A and / or the low-level stacking yard B; Transfer device 4 is installed in high-level stockpile A and low-level stockpile B, and is used to transfer energy storage medium 6 between transport train 2 and stockpile area 3. The power generation device 5 can generate electricity when the transport train 2 carrying the energy storage medium 6 runs from the high-level storage yard A to the low-level storage yard B. The transport train 2 circulates between the high-level storage yard A and the low-level storage yard B, carrying the energy storage medium 6, thereby realizing the transportation of energy storage or power generation. When the system is in the energy storage transportation state, the transport train 2 loads the energy storage medium 6 from the stacking area 3 of the low-level stacking yard B, unloads and stacks it in the stacking area 3 of the high-level stacking yard A, and returns to the low-level stacking yard B empty. This cycle of transportation work continues until the last round of energy storage transportation is set. When the system is in power generation and transportation mode, the transport train 2 loads the energy storage medium 6 from the stacking area 3 of the high-level stockpile A, and after the transport driving power generation device 5 generates electricity, it travels to the stacking area 3 of the low-level stockpile B to stack and unload the energy storage medium 6, and returns to the high-level stockpile A empty. This cycle of transportation work continues until the last round of power generation and transportation is set.

[0032] Based on this gravity energy storage system, the red mud is dried, crushed, mixed with cementing materials, granulated, and loaded into a porous loading container 15 to form red mud solid waste heavy material, which serves as the energy storage medium. It is then stacked in the high-level stockpile A and / or low-level stockpile B of the gravity energy storage system and enters a cyclic loading and unloading transportation process. This completes the gravity transportation and power generation transportation of the gravity energy storage system. Furthermore, based on its stockpile, static curing conditions for spraying reaction liquid and dynamic vibration, ventilation, and stacking and turning during transportation are established to carry out dealkalization and harmless treatment of the red mud.

[0033] This system achieves deep synergy between red mud solid waste treatment and gravity energy storage, overcoming the bottleneck of single-technology approaches. By converting red mud solid waste into an energy storage medium, it solves the problems of high cost and resource consumption associated with traditional gravity energy storage systems using specialized media (concrete blocks, ore), while also overcoming the drawbacks of high energy consumption, long treatment cycles, and secondary pollution risks associated with red mud solid waste treatment. Through a synergistic design of "static curing + dynamic curing," the red mud solid waste treatment process is synchronized with the energy storage / power generation process, eliminating the need for additional land and energy, significantly improving the overall utilization efficiency of the system, shortening the red mud solid waste treatment cycle, and enhancing the stability of treatment results. Traditional static curing of red mud solid waste suffers from uneven local reactions and poor ventilation, leading to long treatment cycles and fluctuating results. This system achieves natural ventilation of the red mud solid waste through the cyclical transportation of dynamic curing, and the movement of the solid waste breaks up the compacted state of the stack, allowing the reaction liquid to fully contact the red mud solid waste. At the same time, the directional spraying during the static curing stage ensures stable reaction conditions, shortening the red mud solid waste treatment cycle compared to traditional technologies.

[0034] For the treatment of red mud solid waste as an energy storage medium in a gravity energy storage system, in addition to adding a reaction liquid spraying operation in the stockpile, no additional procurement or preparation is required. The reaction liquid spraying operation can be carried out by any existing manual or mechanical spraying that can achieve liquid spraying, such as manual spraying, spray arm spraying, mobile spray vehicle spraying, pipeline spraying structure, drone spraying, etc.

[0035] This is a schematic diagram of an embodiment of a high-level or low-level stockpile in this example, including a stockpile area 3, a transfer device 4, and a loading / unloading track 7 located on one side of the stockpile area 3. The loading / unloading track 7 is connected to the transport track 1 of the gravity energy storage system. The stockpile area 3, the transfer device 4, and the loading / unloading track 7 where the transport train 2 stops are all stockpile infrastructure of the gravity energy storage system. In this example, the reaction liquid spraying adopts a pipeline spraying structure, which is arranged above the stockpile area 3. It includes a support frame 8 and multiple spray pipes 9 set on the support frame 8. The spray pipes 9 can be stainless steel rigid pipes (with strong corrosion resistance) or high-strength acid and alkali resistant hoses. When hoses are used, the spray pipes 9 are connected to the support frame 8 through support crossbars. The spray pipes 9 are connected to the reaction reagent supply tank 10. The reaction reagent supply tank 10 stores one or more reaction liquids for dealkalizing red mud. The type of reaction reagent and the spraying volume of the reaction reagent supply tank 10 to the spray pipes can be automatically controlled.

[0036] During static and dynamic curing processes, the sprayed reaction liquid and the leachate flowing out from the reaction of red mud solid waste are collected. Specifically, a collection trough 11 is set below the stockpile area 3. The collection trough 11 is arranged in a concave trough shape and adopts a seepage-proof and flow-guiding design. The collection trough 11 includes a first collection area 12 set below the stockpile area 3 and a second collection area 13 set between the stockpile area 3 and the loading and unloading track 7. The first collection area 12 is arranged in the stockpile area 3 and is the main collection area. The collection area 12 fully covers the solid waste block stacking area in the stockpile area 3 and the spraying range of the spraying device, ensuring that all sprayed waste liquid and heavy block leachate fall into the collection tank 11, achieving collection without dead corners. The second collection area 13 is used to collect leachate from the stockpile area 3 to the loading and unloading track 7. The inside and side walls of the collection tank 11 are completely covered with a seepage-proof layer (such as high-density polyethylene seepage-proof membrane, anti-corrosion concrete lining, etc.), which effectively prevents liquid from leaking into the stockpile foundation and ensures the safety of the underground environment.

[0037] In order to collect the reaction liquid or leachate on the transport train 2, a collection tray 14 is installed on the carriage of the transport train to collect the reaction liquid or leachate dripping from the red mud solid waste during transportation and / or loading and unloading.

[0038] Based on existing gravity energy storage systems, the red mud treatment method of the present invention includes the following specific steps: Preparation of heavy solid waste: The red mud is dried to a moisture content of 20%–30%, crushed and ground into powder. By weight, 80–90 parts of red mud powder, 10–20 parts of hydraulic cementitious powder, 3%–8% of alkali activator and 0.5%–1% of water-reducing agent are weighed. The hydraulic cementitious powder is one or more of silicate cement, alkali-activated slag, lime and fiber materials. Mix red mud powder and hydraulic cementitious powder evenly, add alkali activator and water reducing agent, and then add water at 15% to 20% of the solid powder mass. Mix into a uniform dry thick paste. Use a disc granulator or extrusion pelletizer to make the dry thick paste into spherical or near-spherical red mud-based solid waste particles with a diameter of 5 to 30 mm. Let it stand naturally for 48 hours to allow a preliminary gel film to form on the surface of the particles. A hexahedral square loading container made of high-strength material has liquid-permeable and air-permeable holes at the bottom, side walls, and top, with an opening rate of 40-60%. Positioning interfaces and lifting connectors are provided around the container, and an openable cover is provided at the top. Stacking positioning posts and positioning grooves are provided at the four corners. The porous loading container is placed on a vibrating platform, and red mud-based solid waste particles are loaded into the container using a bucket elevator. Vibration compression is applied during the filling process, with a vibration frequency of 50-150 Hz and an amplitude of 0.5-2 mm, resulting in a bulk density of 1.6-2.0 g / cm³ for the red mud-based solid waste particles. After filling, the cover is closed and locked to obtain a heavy red mud solid waste product.

[0039] Static maintenance: Initially, the red mud solid waste is transported to the high-level or low-level storage yard of the gravity energy storage system, and then stacked according to a matrix pattern, such as... Figure 6 As shown, the specific stacking definition is as follows: the vertical direction along the loading and unloading track 7 is the column direction (X direction), and the stacking area 3 is divided into L1 to L2 according to this direction. m Columns (m is the column number), the vertical direction is the layer direction (Y direction), and the material stacking area 3 is stacked layer by layer in this direction. This matrix arrangement not only facilitates precise positioning of the storage location of each red mud solid waste, but also allows the same batch of red mud solid waste to be centrally stacked in one area, facilitating batch spraying, loading and unloading, and transportation in the stockpile. Furthermore, it can be coordinated with the "dynamic turning" action of the transfer device to achieve orderly movement of the red mud solid waste in the column and layer directions. A batch of red mud solid waste can be defined as a collection of multiple pieces of red mud solid waste transported in one transfer or multiple transfers within a set time. The spraying reaction liquid and the stacking time are uniformly managed, and the storage location, spraying reaction liquid control, and stacking time are all uniformly scheduled and managed by the control center.

[0040] During the stacking process, the reaction liquid is sprayed onto the stacked red mud solid waste from the top or side of each column, with top spraying being preferred. The initial spraying of the red mud solid waste heavy material with the reaction liquid is an alkali activator. After the stockpile conversion, the spraying of the reaction liquid is a dealkali solution. Stockpile conversion refers to the loading of the red mud solid waste heavy material from one stockpile area, transporting it through a gravity energy storage system or through power generation, and then re-entering the stockpile area under static curing conditions. Subsequently, the red mud solid waste heavy material is alternately stored between high-level and low-level stockpile areas, and the reaction liquid is sprayed alternately in sequence. That is, the alkali activator is sprayed when the material is first in the stockpile area, the dealkali solution is sprayed when it is loaded and transported back to the stockpile area under static curing conditions, and the alkali activator is sprayed when it is converted back to the stockpile area under static curing conditions. The reaction liquids are sprayed alternately in sequence.

[0041] When spraying the alkali activator, the spraying interval is 2-4 hours / time, the single spraying amount is 1-2 L / m², and the stacking time is 24-48 hours. The alkali activator is a water glass solution with a modulus of 1.0-2.0 and a mass concentration of 5%-15% or a sodium hydroxide solution with a mass concentration of 5%-10%. When spraying the dealkali solution, the spraying interval is 1-3 hours / time, the single spraying amount is 1.5-2.5 L / m², and the stacking time is 12-48 hours. The dealkali solution is clean water or a dilute acid solution with a pH of 5-6.

[0042] Red mud is rich in free alkali, soluble alkali salts, and potentially active mineral components. This invention uses an alternating spraying method of alkali activator and dealkali removal solution to achieve stepwise solidification and efficient dealkali removal of red mud. First, spray the heavy red mud solid waste with an alkali activator, controlling the spraying interval to be 2-4 hours / time and the single spraying amount to be 1-2 L / m², and let it stand for 24-48 hours. Appropriate and intermittent spraying allows the alkali activator to slowly and evenly penetrate into the red mud and hydraulic cementitious powder matrix, fully activating the activity of silica-alumina minerals, promoting the continuous hydration reaction, and generating dense cementitious products. This can not only encapsulate and solidify some alkaline components and inhibit the later dissolution and migration of alkali, but also form uniform and interconnected pore channels inside the material, laying the structural foundation for the subsequent penetration and flow of dealkali solution, while ensuring that the overall structure of the heavy block gradually hardens and takes shape.

[0043] After the alkali activation and curing is completed, switch to spray dealkali removal solution, control the spray interval to 1-3 hours / time, and the single spray volume to 1.5-2.5L / m², and let it stand for 12-48 hours. Compared with alkali activator, dealkali removal solution uses a smaller spray interval and a larger single spray volume. It can rely on the pore channels formed in the early stage to continuously seep down layer by layer. Through the seepage, flushing and dissolution, the unsolidified free alkali and soluble alkali salts in the red mud are gradually dissolved and carried out with the seepage.

[0044] By differentiating parameters such as low-frequency, small-volume, and long-term static setting of the alkali activator and high-frequency, large-volume, and appropriately long-term static setting of the dealkali solution, an alternating curing mechanism of first activating solidification and then percolating for dealkali removal is formed. This precisely matches the reaction kinetics of gelation hydration and alkali component dissolution, and makes full use of the idle time of natural storage in the gravity energy storage yard. It precisely matches and meets the reaction cycle and curing time requirements for red mud dealkali removal and solidification. By reasonably controlling the spray interval, single spray volume, and static stacking time, it ensures that the reaction solution penetrates evenly layer by layer and reacts fully, avoiding problems such as local reaction saturation and uneven curing that are prone to occur in static stacking. It simultaneously achieves the structural solidification and strengthening of red mud solid waste and the quality improvement and efficiency enhancement of dealkali removal and harmlessness.

[0045] Dynamic maintenance: During the energy storage and / or power generation transportation of the gravity energy storage system, the red mud solid waste heavy materials in the stockpile area are loaded onto the transport train. The transport train is used to circulate between the high-level stockpile and the low-level stockpile of the gravity energy storage system for loading and unloading. This process involves moving the red mud solid waste heavy materials, and the vibration during transportation and ventilation of the loading container holes are used to dynamically maintain the red mud solid waste heavy materials. Vibration and ventilation during transportation enable dynamic oxidation. The low-frequency continuous vibration generated during transportation causes relative slippage and micro-displacement of the red mud-based particles, breaking the dense compacted layer formed by static stacking, expanding the wetting interface of the reaction liquid, and avoiding uneven local reactions. At the same time, vibration drives directional convection of alkali and dealkali solutions within the pores, accelerating the migration of soluble Na⁺ and OH⁻ to the outside, significantly improving the dealkali removal rate and uniformity. Furthermore, vibration promotes the redistribution of gelling components, causing the hydration products / geopolymer gel to form cementation bridges at the particle contact points, improving the overall integrity and compressive strength of the particles.

[0046] During static curing, the reaction between red mud and reaction liquid generates heat of reaction. Ventilation during transportation can accelerate the evaporation of moisture on the particle surface, regulate the humidity and temperature of the system, and avoid local over-wetting or heat accumulation. This not only inhibits the reaction process and reduces the processing efficiency, but also affects the stability of the pile structure. A moderately oxidizing atmosphere promotes the stabilization of heavy metals and reduces the leaching of harmful ions. At the same time, it accelerates the reaction between CO2 and alkali solution, assists in neutralization and alkali reduction, and the airflow keeps the pores between particles open, ensuring uniform penetration of subsequent spray liquid, forming a virtuous cycle of "ventilation-mass transfer-reaction".

[0047] Furthermore, by moving the position of the red mud solid waste through cyclic loading and unloading transportation, "dynamic turning" of the red mud solid waste in the stockpile area can be achieved. This effectively breaks the local reaction saturation layer of red mud solid waste formed by spray reaction when the red mud solid waste is statically stacked, ensuring uniform spray reaction and ventilation of all red mud solid waste in the stockpile area, and promoting the overall reaction efficiency. In a preferred embodiment, during dynamic curing, when the transport train is cyclically loading and unloading between the high-level and low-level stockpiles of the gravity energy storage system, and unloading and stacking from one stockpile area to another, the red mud solid waste in different layers of the same column in the original stockpile area is swapped. This setting allows the red mud solid waste in different layers of the same column in the original stockpile area to be stacked in a staggered manner, disrupting the static stacking layers, breaking the interlayer blockage and reaction dead corners, making the spray penetration of the reaction liquid and the air convection ventilation more uniform and sufficient, and improving the overall dealkalization, harmlessness and solidification curing efficiency of the red mud.

[0048] In one embodiment, during dynamic maintenance, the transport train circulates between the high-level and low-level storage yards of the gravity energy storage system for loading and unloading. During the unloading and stacking process, a reaction solution is sprayed, which can be done intermittently. This allows the reaction solution to be evenly applied to the surface and interlayer gaps of the red mud solid waste during stacking, avoiding problems such as reaction solution accumulation, localized reaction saturation, and uneven penetration that occur during static centralized stacking.

[0049] In a preferred embodiment, during the unloading and stacking process, the material is stacked layer by layer. After stacking one or more layers, the reaction liquid is sprayed once. This can achieve precise layer-by-layer wetting of the entire layer of red mud solid waste, avoiding the defects of surface liquid accumulation, poor internal penetration, and uneven reaction between upper and lower layers caused by stacking the entire material at once and then spraying.

[0050] Curing Cycle: Repeated static and dynamic curing allows red mud solid waste to be alternately stacked and transported between different stockpiles. During stacking, reaction solution is sprayed, and during transport, vibration and ventilation are applied. This cyclical static and dynamic curing process ensures the red mud solid waste is alternately stacked and transported between different stockpiles. Spraying reaction solution during stacking continuously wets, permeates, and reacts the red mud solid waste, providing sufficient reaction conditions for dealkalization and solidification. During transport, vibration generated during transport, combined with the perforations of the porous loading container, facilitates ventilation, effectively loosening the stacked structure and accelerating internal airflow exchange. The alternating cycle of static stacking spraying of reaction solution and transport vibration and ventilation avoids the problems of localized reaction saturation, uneven internal reaction, and poor ventilation that can occur with static stacking. This promotes uniform penetration and full reaction of the reaction solution within the red mud solid waste, significantly improving the overall curing and dealkalization effect and treatment uniformity.

[0051] Regular monitoring: The compressive strength of the red mud solid waste particles within the loading container, and the Na... +The concentration and pH value of the leachate are randomly sampled daily to record the treatment status of the red mud solid waste until the red mud solid waste reaches the predetermined treatment standard. The predetermined treatment standard is: the compressive strength of the red mud-based particles is ≥15MPa, the Na⁺ leaching concentration is ≤0.43g / L, and the pH value reaches 7~7.5.

[0052] Discharge: The red mud that has reached the predetermined treatment standard is removed from the loading container from the system, and new red mud to be treated is put into the solid waste heavy material preparation process. Example 1

[0053] Red mud is dried to a moisture content of 20-30%, crushed and ground into powder. By weight, the powder consists of 85 parts red mud powder, 8 parts silicate cement, 4 parts slag powder, 2 parts lime, and 1 part bamboo and wood fiber powder. The powders are mixed evenly, and then 5% of the total mass of the powder raw materials, 10% water glass solution, and 0.75% of the total mass of the powder raw materials naphthalene sulfonate formaldehyde polymer are added. After mixing evenly, 18% of the solid powder mass of water is added and stirred into a dry, thick paste. The paste is then granulated into spherical particles with a diameter of 25 mm using a disc granulator. The particles are allowed to stand naturally for 48 hours to fully solidify and form a preliminary gel film on the surface, which is the red mud-based solid waste granules.

[0054] A loading container with a hexahedral frame structure made of high-strength steel has liquid-permeable and air-permeable holes on its bottom, side walls, and top, with an opening rate of 55%. The container is equipped with positioning interfaces and lifting connectors for use with transport trains, and has an openable cover on top. Stacking positioning posts and positioning grooves at the four corners ensure stability and alignment accuracy during multi-layer stacking. The loading container is placed on a vibrating platform, and the prepared red mud solid waste granules are loaded into the supporting frame using a bucket elevator. Vibration compression is applied during filling at a frequency of 130Hz and an amplitude of 1.5mm. After vibration compression filling, the bulk density of the red mud-based granules is 2.0g / cm³. After filling, the cover is closed and locked, thus obtaining the red mud solid waste weight.

[0055] The prepared red mud solid waste was transported to the stockpiling area of ​​the elevated stockpile and stacked in rows. The control center recorded the three-dimensional spatial position information and stacking time of each piece of red mud solid waste. During the stacking period, a water glass solution with a modulus of 1.5 and a mass concentration of 12% was sprayed from the top and sides of each row of red mud solid waste. The spraying interval was 3 hours / time, and the single spraying volume was 2L / m². The reaction liquid flowing out of the red mud solid waste after spraying was collected through the collection tank set in the stockpile area. The red mud solid waste was stacked in the stockpiling area of ​​the elevated stockpile for 24 hours.

[0056] After the storage period is reached, the red mud solid waste is loaded onto a transport train. During peak electricity consumption periods, it is transported from the high-level storage yard to the low-level storage yard along the transport track. At the same time, a power generation device is used to generate electricity. During the transportation process, the red mud solid waste is dynamically maintained by ventilation through the liquid permeable and ventilated holes on the loading container and the continuous vibration generated during transportation. The reaction liquid dripping from the red mud solid waste during transportation and / or loading and unloading is collected by the liquid collection tray set on the transport train. After the red mud solid waste is unloaded from the high-level storage yard to the low-level storage yard, it is stacked layer by layer. When stacking one or more layers, the red mud solid waste is sprayed with a dilute acid solution of pH 5.5. At the same time, the control center records the new three-dimensional spatial location information and storage time of each energy storage block in the low-level storage yard. During the storage period in the low-level stockpile, a dilute acid solution with a pH of 5.5 is sprayed from the top and sides of each row of red mud solid waste in that round of stockpiling using a spraying device. The spraying interval is 2 hours per spray, and the spraying volume per spray is 2L / m². The red mud solid waste is stored in the stockpiling area of ​​the low-level stockpile for 24 hours.

[0057] After the storage period is over, the red mud solid waste is loaded onto a transport train again and transported from the low-level storage yard to the high-level storage yard along the transport track during off-peak electricity hours. During the transportation process, the red mud solid waste is also dynamically maintained.

[0058] The static and dynamic curing steps described above were then repeated, and the compressive strength of the red mud solid waste particles in the loading container and the Na content were tested. + The concentration and pH value of the leachate were randomly sampled daily, and the treatment status of the red mud solid waste was recorded. Figure 8 This is a diagram showing the compressive strength test results for red mud solid waste particles. Figure 9 Na, the leachate from the red mud treatment process + Leaching concentration test chart, Figure 10 The graph shows the pH value of the leachate during the red mud treatment process. After 65 days of treatment, the pH value of the red mud solid waste was 18.6 MPa, the Na⁺ leaching concentration was 0.4235 g / L, and the pH value was 7.2, which met the predetermined treatment standards of red mud solid waste particles having a compressive strength ≥15 MPa, a Na⁺ leaching concentration ≤0.43 g / L, and a pH value of 7~7.5. The red mud that has reached the predetermined treatment standard is removed from the loading container and the new red mud to be treated is introduced into the solid waste heavy material preparation process.

[0059] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0060] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A red mud treatment method based on gravity energy storage, characterized in that, Includes the following steps: Preparation of solid waste heavy materials: After drying and crushing red mud, the red mud powder is mixed with cementitious materials and granulated to obtain red mud-based particles; the red mud-based particles are loaded into a porous loading container to form red mud solid waste heavy materials; Static curing: The red mud solid waste heavy material is transported to the high-level stockpile and / or low-level stockpile of the gravity energy storage system, and stacked in the stockpile area. During the stockpile period, the red mud solid waste heavy material is sprayed with the reaction liquid for dealkalization. Dynamic maintenance: During the energy storage and / or power generation transportation of the gravity energy storage system, the red mud solid waste heavy materials in the stockpile area are loaded onto the transport train. The transport train is used to circulate between the high-level stockpile and the low-level stockpile of the gravity energy storage system for loading and unloading. The position of the red mud solid waste heavy materials is moved, and the vibration during transportation and the ventilation of the loading container holes are used to dynamically maintain the red mud solid waste heavy materials. Maintenance cycle: Repeated static and dynamic maintenance, so that the red mud solid waste is alternately stacked and transported between different stockpiles. During stacking, reaction liquid is sprayed, and vibration and ventilation are used during transportation. Regular monitoring: The compressive strength of the red mud solid waste particles within the loading container, and the Na... + The concentration and pH value of the leachate are randomly sampled daily, and the treatment status of the red mud solid waste is recorded until the red mud solid waste reaches the predetermined treatment standard. Discharge: The red mud that has reached the predetermined treatment standard is removed from the loading container from the system, and new red mud to be treated is put into the solid waste heavy material preparation process.

2. The red mud treatment method based on gravity energy storage according to claim 1, characterized in that, In the preparation of solid waste heavy materials, red mud is dried to a moisture content of 20% to 30%; the cementing material is a hydraulic cementitious powder, which, by weight, consists of 80 to 90 parts red mud powder and 10 to 20 parts hydraulic cementitious powder; the hydraulic cementitious powder is one or a mixture of silicate series cement, alkali-activated slag, lime, and fiber materials.

3. The red mud treatment method based on gravity energy storage according to claim 2, characterized in that, In the preparation of solid waste heavy materials, an alkali activator and a water-reducing agent are added, and then an appropriate amount of water is added and mixed into a uniform dry thick paste; the amount of alkali activator added is 3% to 8% of the total mass of the powder raw materials, the amount of water-reducing agent added is 0.5% to 1% of the total mass of the powder raw materials, and the amount of mixing water is 15% to 20% of the mass of the solid powder.

4. The red mud treatment method based on gravity energy storage according to claim 3, characterized in that, The dry, thick paste is made into red mud-based solid waste granules, left to stand naturally, and then a preliminary gel film is formed on the surface of the granules before being loaded into a porous loading container.

5. The red mud treatment method based on gravity energy storage according to claim 1, characterized in that, In the preparation of solid waste heavy materials, the porous loading container has a rectangular structure with liquid-permeable and air-permeable holes on the top, bottom and side walls, with an opening rate of 40% to 60%.

6. The red mud treatment method based on gravity energy storage according to claim 1, characterized in that, In the preparation of solid waste heavy materials, the red mud-based particles are loaded into a porous loading container and then vibrated and compressed. The vibration frequency is 50-150 Hz and the amplitude is 0.5-2 mm. After vibration compression and filling, the bulk density of the red mud-based particles is 1.6-2.0 g / cm³.

7. The red mud treatment method based on gravity energy storage according to claim 1, characterized in that, In static curing, the reaction solution includes an alkali activator and a dealkali solution. The alkali activator is sprayed when the red mud solid waste is first piled up, and the dealkali solution is sprayed after the stockpile is changed. Subsequently, the reaction solution is sprayed alternately as the red mud solid waste is stored alternately between high-level and low-level stockpiles. When spraying the alkali activator, the spraying interval is 2 to 4 hours / time, the single spray volume is 1 to 2 L / m², and the stockpiling time is 12 to 48 hours. When spraying the dealkali solution, the spraying interval is 1 to 3 hours / time, the single spray volume is 1.5 to 2.5 L / m², and the stockpiling time is 12 to 48 hours.

8. The red mud treatment method based on gravity energy storage according to claim 7, characterized in that, The alkali activator is a water glass solution or a sodium hydroxide solution, wherein the water glass solution has a modulus of 1.0 to 2.0 and a mass concentration of 5% to 15%, and the sodium hydroxide solution has a mass concentration of 5% to 10%; the dealkali solution is water or a dilute acid solution, wherein the pH value of the dilute acid solution is 5 to 6.

9. The red mud treatment method based on gravity energy storage according to claim 1, characterized in that, During regular monitoring, the treatment standards are set as follows: the compressive strength of red mud solid waste particles ≥15MPa, Na⁺ leaching concentration ≤0.42g / L, and pH value reaching 7~7.

5.

10. A red mud treatment method based on gravity energy storage according to claim 1, characterized in that, During dynamic maintenance, the transport train circulates between the high-level and low-level storage yards of the gravity energy storage system for loading and unloading. During the unloading and stacking process, the reaction liquid is sprayed.

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