System and method for efficiently removing silicon from mine concentrated brine

Abstract

This invention provides a system and method for efficiently removing silicon from concentrated mine brine, solving the problems of large dosage of silicon removal reagents, slow silicon settling rate, and poor silicon removal effect under high salinity conditions in practical engineering. The system includes a heterogeneous membrane device, a primary reverse osmosis device, an integrated hardening and silicon removal device, an ion exchange device, a secondary reverse osmosis device, an electrostatic separation and concentration device, a filtration device, a rapid silicon removal settling device, an evaporation crystallization device, and two recycled water tanks. The multi-coupling process for silicon removal has the advantages of integrated removal of dissolved and colloidal silicon, reducing the impact of salt effects, and features low reagent consumption and high efficiency. It is also highly compatible with existing zero-discharge mine water systems, effectively controlling the silicon content entering the evaporation crystallization system, reducing the risk of scaling in subsequent evaporation crystallization processes, and ensuring the stable operation of the evaporation crystallization process, thus demonstrating broad application prospects.

Description

Technical Field

[0001] This invention belongs to the field of deep silicon treatment technology in industrial wastewater, specifically relating to a system and method for efficiently removing silicon from concentrated mine brine. Background Technology

[0002] Mine brine is concentrated brine produced during coal mining and treated by reverse osmosis in a desalination section. In 2019, my country's mine water production was approximately 7.1 billion cubic meters. 3 Na + Ca 2+ Cl - SO4 2- The plasma concentration is as high as 1000-4000 mg / L, and in some cases even exceeds 40000 mg / L. Currently, the main process flow for zero-discharge mine water treatment systems built in northern China includes three stages: desalination, secondary concentration, and evaporation crystallization. The core processes in the desalination and secondary concentration stages utilize reverse osmosis membrane concentration technology, with auxiliary processes including pretreatment such as hardening and impurity removal to meet the requirements of reverse osmosis feed water. In actual project operation, the concentrated brine after two stages of reverse osmosis concentration has high impurity and silicon content, which affects the stability of the subsequent evaporation crystallization process and the quality of the crystallized salt. Therefore, effective measures must be taken to remove silicon from the concentrated brine after reverse osmosis concentration before evaporation crystallization.

[0003] Silicon in mine brine exists mainly in the following four forms: (1) dissolved silica compounds in molecular and ionic states, (2) unstable colloidal silica, (3) adsorbed silica compounds, and (4) relatively stable coarse-grained silica compounds. Among them, silica in forms (3) and (4) can be effectively removed in underground precipitation and filtration processes. Colloidal silica in mine brine often changes with conditions. When the water contains more carbon dioxide and the pH and temperature are low, the originally dissolved silica will precipitate and further polymerize into colloidal polysilicic acid. When the pH and temperature of the water are high, this colloidal silica compound will transform into dissolved silica. Both forms (i.e., forms (1) and (2)) of silica coexist in actual projects and will change with different processes. Therefore, in actual water treatment processes, the removal of these two forms of silica is more difficult. In actual mine brine zero-discharge projects, coagulation and sedimentation are often used to remove colloidal silica. Afterward, scale inhibitors are added to prevent dissolved silica from depositing on the membrane surface. The concentrated brine after reverse osmosis is then removed by adsorption and precipitation with silica removal agents. While coagulation and sedimentation remove most colloidal silica, residual colloidal silica slowly deposits on the membrane surface, forming an adhesive layer that is difficult to clean. Scale inhibitors require the addition of chemicals to the water system to prevent silica compounds from precipitating from the supersaturated silica solution, thus failing to remove dissolved silica at its source. Furthermore, after reverse osmosis concentration, the TDS (Total Dissolved Solids) increases, and subsequent silica removal with silica removal agents suffers from problems such as large dosage requirements and slow sedimentation rates of the adsorbed silica precipitates due to the salt effect.

[0004] Chinese patent application CN108751523A discloses a method and system for removing hardness and silicon from high-salt wastewater and for concentration treatment. First, lime, soda ash, and magnesium oxide are added to the high-salt wastewater for silicon removal treatment. Then, the wastewater is filtered through a tubular membrane. After adjusting the pH of the permeate, it is passed through a weak acid cation exchange resin to remove hardness, and then through a carbon separator to remove alkalinity. After adjusting the pH again, the permeate is concentrated through reverse osmosis. However, this technical solution has the problem of large reagent dosage and unsatisfactory silicon removal effect under high-salt conditions.

[0005] Chinese patent application CN109734216A discloses a treatment system and process for removing hardness, silica, and turbidity from high-salt wastewater. It couples the chemical coagulation and sedimentation process with the membrane filtration process, using a chemical reaction to precipitate silica hardness into particulate matter, which is then sent to a membrane sludge-water separation device for filtration and removal. However, in actual project applications, there are problems such as difficulty in particulate matter settling, high water content, large footprint for sludge thickening treatment, and suspended particulate matter entering subsequent membrane devices, causing membrane clogging, frequent cleaning, and rapid decline in treatment capacity.

[0006] Chinese patent application CN108059269A discloses a system and process for removing silica and hardness from industrial wastewater. The system employs conditioning, reaction, flocculation, and precipitation processes to remove hardness and silica. However, the added reagents do not include any reagents for removing hardness, and the pH values ​​have opposite effects on the removal of hardness and silica, thus failing to solve the problem of hardness removal.

[0007] It is evident that none of the aforementioned patent applications considered the form of silicon in wastewater or the changes in silicon form at different treatment stages during the silicon removal process. They directly adopted chemical coagulation and sedimentation methods without taking into account the impact of salt on silicon removal, resulting in unsatisfactory silicon removal effects. In actual engineering applications, chemical silicon removal suffers from long sedimentation times and low sedimentation density, leading to pool overflow.

[0008] Therefore, it is necessary to explore a system and method for efficiently removing silicon from concentrated mine brine. Summary of the Invention

[0009] The purpose of this invention is to solve the problems of large dosage of silicon removal agents, slow silicon sedimentation rate, and poor silicon removal effect under high salinity conditions in practical engineering, and to provide a system and method for efficiently removing silicon from concentrated brine in mines.

[0010] To achieve the above objectives, the technical solution provided by this invention is:

[0011] A type of agglomerant, characterized in that its active ingredient is an inorganic mineral that has undergone sequential acid washing and positive charge modification; its particle size is 1-10 mm, and its density is 2.0-6.0 g / cm³. 3 The porosity is 20-80%;

[0012] The inorganic minerals are natural minerals or solid waste discharged from coal chemical industry, coal mine and power plant, such as gasification slag, coal gangue, carbide slag, attapulgite, fly ash and other high-density materials.

[0013] The preparation method of the above-mentioned agglomerant is characterized by including the following steps:

[0014] 1) Pretreatment, aimed at dispersing inorganic minerals.

[0015] The inorganic minerals are evenly spread out and dried in a muffle furnace. The dried inorganic minerals are then taken out and prepared into an inorganic mineral suspension with a mass fraction of 10-50%.

[0016] Add a dispersant (e.g., sodium hexametaphosphate) to the inorganic mineral suspension and stir at room temperature for 20-60 minutes; wherein the mass ratio of dispersant to inorganic mineral is 0.1-0.6:1.

[0017] The stirred inorganic mineral suspension was centrifuged and washed to remove the dispersant, and then dried to obtain pretreated inorganic minerals for later use.

[0018] 2) Pickling

[0019] Pretreated inorganic minerals are prepared into a suspension with a mass fraction of 4-6% using water. Hydrochloric acid is then added to the suspension (using hydrochloric acid for acidification is safer here) to form a suspension containing 0.01-1 mol / L of hydrochloric acid. The suspension is stirred at 55-65℃ for 1.5-2.5 h, and then washed until neutral to obtain the acid-washed suspension.

[0020] 3) Positive charge modification

[0021] Under stirring conditions, a silane coupling agent solution (e.g., an aminosilane solution) with a molar concentration of 0.8-1.2 mol / L is slowly added to the suspension obtained in step 2), and stirred at room temperature for 1.5-2.5 h to obtain a mixed suspension.

[0022] 4) Post-processing

[0023] The mixed suspension obtained in step 3) was dried by spray drying to obtain an agglomerator.

[0024] A system for efficiently removing silicon from concentrated mine brine is characterized by comprising a heterogeneous membrane device, a primary reverse osmosis device, an integrated hardening and silicon removal device, an ion exchange device, a secondary reverse osmosis device, an electro-separation concentration device, a filtration device, a silicon removal rapid sedimentation device, an evaporation crystallization device, a first reclaimed water tank, and a second reclaimed water tank.

[0025] Among them, the heterogeneous membrane device is used to remove impurities from concentrated brine in mines. These impurities are a collective term for suspended solids, bacteria, and colloidal silica, etc.

[0026] The first-stage reverse osmosis unit removes salt ions from the permeate water of the heterogeneous membrane unit to form permeate water and concentrate water. The permeate water enters the reclaimed water tank for reuse, and the concentrate water enters the integrated hardness and silica removal unit.

[0027] The integrated hardness and silicon removal device utilizes chemical reactions, hardness removal precipitation adsorption, and agglomeration adsorption to rapidly precipitate and remove dissolved silicon and hardness from the concentrate of the first-stage reverse osmosis unit;

[0028] Ion exchange devices are used to remove residual hardness and residual polyvalent cations, such as iron ions and manganese ions, from the product water of integrated hardness and silicon removal devices.

[0029] The two-stage reverse osmosis unit removes salt ions from the permeate of the ion exchange unit to form permeate and concentrate. The permeate enters the recycled water tank for reuse, while the concentrate enters the electro-separation and concentration unit.

[0030] The electrostatic separation and concentration unit is used to separate salt ions and soluble silica in the concentrate from the secondary reverse osmosis unit to form permeate and concentrate. The concentrate (i.e., the part of water containing salt ions) enters the evaporation and crystallization unit. The permeate enters the filtration unit to remove the colloidal silica that has saturated and precipitated, and then enters the silica removal rapid sedimentation unit to remove dissolved silica through agglomeration adsorption and rapid sedimentation. The generated sludge is returned to the integrated hardness removal and silica removal unit after charge adsorption and mesh capture to remove dissolved silica. The generated permeate (here, the permeate after silica removal contains calcium and magnesium ions and hardness, and is returned to the ion exchange unit for further hardness removal) is returned to the ion exchange unit.

[0031] The agglomerating agent used in the integrated hardening and silicon removal device and the rapid silicon removal sedimentation device is the aforementioned agglomerating agent.

[0032] It can be seen that the treated water of the entire system is the product water of the first-stage reverse osmosis unit and the second-stage reverse osmosis unit.

[0033] Furthermore, the heterogeneous membrane device is a microfiltration or ultrafiltration level filtration device, including a feed water pump, a membrane element, a backwash water pump, a cleaning water pump, and a cleaning water tank;

[0034] The membrane core uses a heterogeneous membrane, with a non-woven fabric bottom layer and a flexible polymer material surface layer. The surface layer has a conical structure with smaller pores near the surface and larger pores near the bottom layer. When the membrane flux decreases, backwashing can be used to restore the flux. Compared with existing microfiltration or ultrafiltration membranes, it has the advantages of easy cleaning, a soft surface, rapid separation of clogging material from the membrane, and minimal flux decay. The performance requirements for the membrane core are: a permeate recovery rate of 80-99%, an operating pressure of 0.01-10 bar, a permeate turbidity of less than 0.01 NTU, and a colloidal silica removal rate of over 90%.

[0035] Furthermore, the primary reverse osmosis unit includes an inlet pump, a high-pressure pump, a reverse osmosis membrane element, a cleaning water pump, a chemical cleaning water pump, and a cleaning water tank;

[0036] The reverse osmosis membrane core uses an atmospheric pressure or high pressure reverse osmosis membrane, and its performance requirements are a product water recovery rate of 50%-90%, an operating pressure of 1-50 bar, and a product water TDS of less than 100 mg / L.

[0037] Furthermore, the integrated hardening and desiliconization device, depending on the influent water quality, also has the functions of hardening and desiliconization. It mainly includes a first reaction tank, a second reaction tank, a settling zone, and a separation zone.

[0038] Both the first and second reaction tanks are equipped with dosing pumps and agitators; the separation zone is equipped with a sludge thickening tank and a membrane filtration device (which is used for sludge-water separation in the separation zone); the second reaction tank and the separation zone are connected by a sludge recirculation pump to return sludge from the separation zone to the second reaction tank.

[0039] The incoming water first passes through the first reaction tank where the pH is adjusted (controlled at 8-10) and a precipitation reaction occurs using sodium hydroxide or calcium hydroxide. Then it enters the second reaction tank, where a dosing pump sequentially adds sodium carbonate, magnesium oxide or magnesium chloride, and a flocculant. First, calcium carbonate and magnesium hydroxide precipitates are produced. Then, dissolved silicon is adsorbed onto the surface of magnesium hydroxide. The magnesium hydroxide precipitate with adsorbed silicon and the calcium carbonate precipitate are adsorbed onto the surface of the flocculant and quickly settle to the bottom of the tank. A small number of floating particles are removed by a membrane filtration device (vacuum micro-negative pressure heterogeneous membrane).

[0040] The mass ratio of magnesium oxide or magnesium chloride to dissolved silicon is 0.5-1.5:1, and the dosage of agglomerating agent is 1-5 mg / L. The treatment effect of this device is: hardness removal rate of 50-90% and silicon removal rate of over 80%. The whole process does not require the addition of coagulants, flocculants and sodium aluminate desiliconizing agents, reducing the pollution to the subsequent reverse osmosis membrane system.

[0041] Furthermore, the ion exchange device includes an inlet pump, a regenerated water pump, a resin tank, a backwash pump, and a regeneration reagent tank; wherein, the resin tank uses strong acid, weak acid, or chelated cation exchange resin, and the resin output water effect of the device is: hardness removal rate of over 99%, water hardness of less than 1 mg / L, and polyvalent cation removal rate of over 90%, preventing polyvalent ions from depositing and contaminating the surface of the subsequent reverse osmosis membrane.

[0042] Furthermore, the secondary reverse osmosis unit includes a feed water pump, a reverse osmosis membrane element, a cleaning water pump, a chemical cleaning water pump, and a cleaning water tank; wherein, the reverse osmosis membrane element adopts a high-pressure membrane, and its performance requirements are: a product water recovery rate of 50-90% and an operating pressure of 5-100 bar.

[0043] Furthermore, the electro-separation and concentration device includes electrodes, electrode plates, electrode plate separation partitions, and cation and anion exchange membranes. This device functions through positive and negative electrodes and ion exchange membranes. The difference in migration between cations and anions and dissolved silicon (orthosilicic acid, metasilicic acid, molecular silica) under the influence of an electric field achieves the functions of diluting salt ions and concentrating silicon in the product water. The TDS in the product water is 1000-20000 mg / L, and the silicon content in the product water is more than 90% of the influent, while the silicon content in the concentrated water is less than 10% of the influent. The electro-separation and concentration device combines electro-deionization, electrodialysis, capacitive deionization technology, continuous electro-desalination technology, and cation and anion exchange membranes.

[0044] The filtration device includes an inlet pump, a filter membrane core, a membrane housing, a backwash water pump, and a backwash water tank. It is a multi-media, self-cleaning, microfiltration, or ultrafiltration device. The filtration device removes colloidal silica that has been saturated and precipitated in the influent water after concentration, and the remaining dissolved silica enters the subsequent silica removal rapid sedimentation device.

[0045] The rapid sedimentation device for silicon removal includes a reaction tank 1, a reaction tank 2, a reagent dosing tank, a reagent dosing pump, a flocculant dosing tank, a flocculant dosing pump, a membrane filtration device, a vacuum pump, a sludge storage area, and a sludge return pump. In reaction tank 1, magnesium oxide or magnesium chloride and a flocculant are added sequentially, with a magnesium oxide or magnesium chloride to dissolved silicon mass ratio of 0.5-2:1 and a flocculant dosage of 1-10 mg / L. Reaction tank 2 consists of a sedimentation zone and a vacuum-sealed, low-negative-pressure heterogeneous membrane filtration assembly. The settled sludge is returned to the front-end integrated hardness and silicon removal device, producing water with a turbidity of 0.01 NTU and a silicon removal rate of over 80%. The produced water and the water from the integrated hardness and silicon removal device are sent together to an ion exchange device for hardness removal and recycling.

[0046] The evaporation crystallization device is used to evaporate and crystallize the concentrated water in the electrostatic separation and concentration device to produce salt, thereby maximizing the recovery of water resources in the wastewater. The evaporation crystallization device can be an MVR evaporation crystallization device, a single-effect, a double-effect, or a multi-effect evaporation crystallization device.

[0047] The method for efficiently removing silicon from concentrated mine brine using the above system is characterized by the following steps:

[0048] S1. The concentrated brine from the mine, with its pH adjusted to less than 7, enters the heterogeneous membrane unit. Impurities in the mine water (such as insoluble colloidal silica in the water and silica adsorbed on the surface of particles) are removed through the heterogeneous membrane. The produced water then enters the first-stage reverse osmosis unit.

[0049] S2. The permeate from the heterogeneous membrane unit is concentrated by the first-stage reverse osmosis unit. The permeate from the first-stage reverse osmosis unit enters the reclaimed water tank for reuse, while the concentrate from the first-stage reverse osmosis unit enters the integrated hardness and silica removal unit for further treatment.

[0050] S3. The concentrate from the first-stage reverse osmosis unit enters the integrated hardness and silica removal unit. Through chemical reactions, hardness removal precipitation adsorption, and agglomeration adsorption, dissolved silica and hardness in the first-stage reverse osmosis concentrate are rapidly removed by precipitation. The permeate from the integrated hardness and silica removal unit enters the ion exchange unit.

[0051] S4. The water produced by the integrated hardness and silicon removal unit undergoes further hardness removal through ion exchange, ensuring stable operation of subsequent membranes and evaporation crystallization. The water produced by the ion exchange unit then enters the secondary reverse osmosis unit.

[0052] S5. The permeate from the ion exchange unit is concentrated by the secondary reverse osmosis unit. The permeate from the secondary reverse osmosis unit enters the reclaimed water tank for reuse. The concentrated water from the secondary reverse osmosis unit enters the electro-separation and concentration unit.

[0053] S6. The concentrate from the secondary reverse osmosis unit is separated into salt ions and silicon by an electro-separation and concentration unit. The product water from the electro-separation and concentration unit enters the filtration unit, and the concentrate from the electro-separation and concentration unit enters the evaporation and crystallization unit to crystallize and recycle salt.

[0054] S7. The water produced by the electro-separation and concentration unit is filtered to remove the colloidal silica that has been saturated and precipitated after concentration, and the water then enters the silica removal and rapid sedimentation unit.

[0055] S8. The filtration device produces water that undergoes chemical reaction adsorption and agglomeration adsorption to quickly precipitate and remove dissolved silica. The settled sludge is returned to the integrated hardening and silica removal device through charge adsorption and mesh capture to enhance the adsorption and capture effect of silica removal sedimentation. The produced water enters the ion exchange device for hardening removal and then re-enters the secondary reverse osmosis device for circulation treatment.

[0056] In summary, the silicon removal process using the above-mentioned efficient system for removing silicon from mine brine is as follows: First, colloidal silicon in the mine brine with pH < 7 is removed through a heterogeneous membrane device. After primary reverse osmosis concentration, the permeate enters an integrated hardness and silicon removal device where dissolved silicon and hardness are rapidly removed through chemical reactions, hardness removal precipitation adsorption, and agglomeration adsorption. The permeate is then filtered through a vacuum micro-negative pressure heterogeneous membrane to remove a small amount of unsettled particles. After further hardness removal through ion exchange, the permeate enters a secondary reverse osmosis device for concentration. The permeate then enters an electrostatic separation concentration device to separate salt ions from soluble silicon. The separated permeate is then evaporated to crystallize salt. The separated permeate enters a filtration device to remove saturated colloidal silicon, and then enters a rapid silicon removal sedimentation device where dissolved silicon is rapidly removed through agglomeration adsorption. The resulting sludge is recycled back to the integrated hardness and silicon removal device to enhance the adsorption and capture effects of silicon removal and hardness removal precipitation. The permeate then enters an ion exchange resin for hardness removal and is then recycled back to the secondary reverse osmosis device.

[0057] The principle of this invention:

[0058] This invention combines membrane filtration technology (corresponding to a heterogeneous membrane device), chemical adsorption precipitation + agglomeration adsorption rapid precipitation technology (corresponding to an integrated hardness and silicon removal device), salt concentration and silicon separation technology (corresponding to an electrostatic separation concentration device + filtration device), and sludge recirculation and capture silicon removal technology (corresponding to the design of returning sludge from a rapid silicon removal settling device to an integrated hardness and silicon removal device). It removes colloidal silicon from water through heterogeneous membrane deep filtration, removes dissolved silicon through hardness precipitation and sludge adsorption and precipitation, and achieves effective separation of silicon and salt ions in water through salt concentration and separation technology, resulting in increased silicon concentration in the produced water. This lays the foundation for reducing salt interference in subsequent agglomeration adsorption rapid precipitation technology for silicon removal.

[0059] The overall process utilizes a strategy of mutual conversion between two forms of silicon (forms (1) and (2) in the background art) to remove total silicon. The specific mechanism is as follows: First, the pH of the concentrated mine brine is adjusted to <7, so that some dissolved silicon is converted into colloidal silicon and removed by a heterogeneous membrane device; then, the pH of the integrated hardening and silicon removal device is controlled at 8-10, so that magnesium hydroxide adsorbs dissolved silicon and colloidal silicon, and then adsorbs them on the surface of the agglomerating agent to remove total silicon; the pH of the water produced by the electro-separation concentration device is <7, so some dissolved silicon is converted into colloidal silicon and removed by a subsequent filtration device; then it enters the silicon removal rapid sedimentation device with a pH of 8-10, where magnesium hydroxide adsorbs dissolved silicon and colloidal silicon, and then adsorbs them on the surface of the agglomerating agent to remove total silicon; thus, the entire process achieves the complete removal of colloidal and dissolved silicon.

[0060] Advantages of this invention:

[0061] 1. The silicon removal system of this invention addresses the current situation where both colloidal and dissolved silicon exist in mine water. It adopts a two-stage removal of colloidal silicon using "heterogeneous membrane filtration technology and filtration technology" to reduce the load on subsequent chemical adsorption silicon removal and lower the risk of reverse osmosis membrane fouling. It uses an "integrated hardening and silicon removal device + rapid silicon removal sedimentation device + salt concentration and silicon separation technology" to remove dissolved silicon. Different removal methods are used for different forms of silicon, which has the advantages of high removal efficiency and wide applicability.

[0062] 2. This invention addresses the challenges of low silicon removal rates and high reagent dosages under high-salinity conditions in existing zero-discharge mine water systems. It innovatively employs electrostatic separation and concentration technology to separate salt ions from silicon in high-salinity brine from secondary reverse osmosis. The resulting product water is characterized by low salinity and high silicon content, while the concentrate is characterized by high salinity and low silicon content. This high-salinity, low-silicon concentrate is then introduced into the subsequent evaporation and crystallization process, reducing the risk of silicon scaling during evaporation and crystallization and ensuring the stable operation of the evaporation and crystallization process.

[0063] 3. The integrated hardening and silicon removal device and the rapid silicon removal sedimentation device in this invention use chemical adsorption and agglomeration adsorption rapid sedimentation technology to remove dissolved silicon without adding coagulants or flocculants, reducing the risk of PAM and PAC contamination in the subsequent reverse osmosis membrane system. The magnesium hydroxide produced during hardening can be used for silicon removal, reducing the dosage of magnesium oxide / magnesium chloride. It features high removal efficiency, low reagent dosage, and fast sedimentation speed. Due to the fast sedimentation speed, the required sedimentation area is reduced, the overall device footprint is reduced, and the investment cost is lowered. At the same time, the sludge from the rapid silicon removal sedimentation device is returned to the integrated hardening and silicon removal device to enhance the adsorption and capture of silicon precipitation. To improve efficiency and reduce the dosage of chemicals and flocculants, the secondary reverse osmosis concentrate undergoes concentration and filtration in an electrostatic separation unit. However, the prolonged concentration time causes the added scale inhibitor to become ineffective, thus reducing its impact on silica removal efficiency. The flocculant used is an inorganic mineral (natural mineral or solid waste discharged from coal chemical, coal mine, and power plant projects) that has undergone acid washing and positive charge modification. Its raw materials are solid waste from coal mining, power plant, and coal chemical projects, enabling high-quality resource utilization of solid waste. This invention utilizes agglomeration technology to recycle solid waste, reduce the dosage of chemical agents, lower silica removal costs, and achieve rapid and efficient silica removal.

[0064] 4. This invention not only effectively separates salt ions from silicon through an electrostatic separation and concentration device, but also concentrates the secondary reverse osmosis concentrate, thereby increasing the salt concentration of the feed water to the evaporation crystallization system, reducing the scale of the subsequent evaporation crystallization system, and effectively reducing the investment and operating costs of the entire system.

[0065] 5. The heterogeneous membrane device used in this invention has a conical surface structure with small pore size near the surface and large pore size near the bottom. When the membrane flux decreases, backwashing can quickly restore the membrane flux. Compared with existing microfiltration or ultrafiltration membranes, it has the advantages of easy cleaning, soft surface, rapid separation of blockages from the membrane, and small membrane flux decay.

[0066] 6. This invention optimizes the silicon removal process using multiple coupling methods and introduces a designed agglomerating agent, which has the advantages of integrated removal of dissolved and colloidal silicon, reduces the impact of salt effects, and features low reagent consumption and high efficiency. It is also highly compatible with existing zero-discharge mine water systems, effectively controls the silicon content entering the evaporation crystallization system, reduces the risk of scaling in subsequent evaporation crystallization processes, and ensures the stable operation of the evaporation crystallization process, thus having broad application prospects. Attached Figure Description

[0067] Figure 1 This is a system flowchart of the present invention;

[0068] Figure 2 The process flow diagram for silicon removal used in Comparative Example 1;

[0069] Among them: 1-mine concentrated brine, 2-heterogeneous membrane device, 3-first-stage reverse osmosis device, 4-reclaimed water tank one, 5-hardness and silica removal integrated device, 6-ion exchange device, 7-second-stage reverse osmosis device, 8-reclaimed water tank two, 9-electrolysis concentration device, 10-evaporation crystallization device, 11-filtration device, 12-silica removal rapid sedimentation device. Detailed Implementation

[0070] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0071] A system for efficiently removing silicon from mine water, such as Figure 1 As shown, it includes a heterogeneous membrane device, a primary reverse osmosis device, an integrated hardening and desiliconization device, an ion exchange device, a secondary reverse osmosis device, an electrostatic separation and concentration device, a filtration device, a desiliconization rapid sedimentation device, an evaporation and crystallization device, a reclaimed water tank 1, and a reclaimed water tank 2.

[0072] The heterogeneous membrane device is used to remove suspended solids, bacteria, and colloidal silica from concentrated mine brine (after adjusting the pH of the brine to less than 7). It is a microfiltration or ultrafiltration system and includes a feed pump, membrane element, backwash pump, cleaning pump, and cleaning tank. The membrane element is a heterogeneous membrane with a non-woven fabric bottom layer and a flexible polymer surface layer. The surface layer has a conical structure with smaller pores near the surface and larger pores near the bottom layer. The membrane element's performance requirements are a permeate recovery rate of 80-99%, an operating pressure of 0.01-10 bar, a permeate turbidity of less than 0.01 NTU, and a colloidal silica removal rate of over 90%.

[0073] The first-stage reverse osmosis unit removes salt ions from the water through a reverse osmosis membrane, enabling the product water to be reused. It includes a feed water pump, a high-pressure pump, a reverse osmosis membrane element, a cleaning water pump, a chemical cleaning water pump, and a cleaning water tank. The reverse osmosis membrane element uses an atmospheric pressure or high-pressure reverse osmosis membrane, with performance requirements of a product water recovery rate of 50-90%, an operating pressure of 1-50 bar, and a product water TDS of less than 100 mg / L.

[0074] The integrated hardening and silica removal device removes calcium and magnesium ions from water using methods such as dual alkali treatment or lime addition, depending on the water quality. It also adds magnesium oxide and magnesium chloride to remove silica, and a flocculant to accelerate the settling rate of calcium and magnesium precipitation and magnesium hydroxide precipitation (which adsorbs silica). The device includes a first reaction tank, a second reaction tank, a settling zone, and a separation zone. Both the first and second reaction tanks are equipped with dosing pumps and agitators. The separation zone contains a sludge thickening tank and a membrane filtration device. The second reaction tank and the separation zone are connected by a sludge recirculation pump, which returns sludge from the separation zone to the second reaction tank.

[0075] The ion exchange unit is used to further remove residual hardness and residual polyvalent cations from the permeate of the integrated hardness and silica removal unit. It includes an influent pump, a regenerated water pump, a resin tank, a backwash pump, and a regeneration reagent tank. The resin tank uses strong acid, weak acid, or chelated cation exchange resins. The resin effluent effect of this unit is: hardness removal rate of over 99%, permeate hardness of less than 1 mg / L, and polyvalent cation removal rate of over 90%, preventing polyvalent ions from depositing and fouling the surface of the subsequent reverse osmosis membrane.

[0076] The secondary reverse osmosis unit removes salt ions from the product water of the ion exchange unit through a osmotic membrane, allowing the product water to be reused. It includes a feed water pump, a reverse osmosis membrane element, a cleaning water pump, a chemical cleaning water pump, and a cleaning water tank. The reverse osmosis membrane element uses a high-pressure membrane, with a performance requirement of 50-90% recovery rate and an operating pressure of 5-100 bar.

[0077] The electro-separation and concentration device separates and concentrates anions and cations in water by driving the electrode electric field, thereby reducing the salt ion content in the treated water. In the electric field, the migration of dissolved silica and colloidal silica is small. As the product water flows out, the electro-separation and concentration device includes electrodes, electrode plates, electrode plate separation partitions, and anion and cation exchange membranes.

[0078] The filtration device is a self-cleaning, multi-media, microfiltration or ultrafiltration device. The filtration device removes colloidal silica that has been saturated and precipitated in the water after concentration. The remaining dissolved silica enters the subsequent silica removal rapid sedimentation device, which includes an inlet pump, a filter membrane element, a membrane housing, a backwash water pump and a backwash water tank.

[0079] The desiliconization rapid settling device includes reaction tank 1, reaction tank 2, reagent dosing tank, reagent dosing pump, flocculant dosing tank, flocculant dosing pump, membrane filtration device, vacuum pump, sludge temporary storage area, and sludge return pump. Magnesium oxide or magnesium chloride and flocculant are added to reaction tank 1. Reaction tank 2 consists of a settling zone and a vacuum micro-negative pressure heterogeneous membrane filtration device. The settled sludge is returned to the front-end integrated hardening and desiliconization device to remove dissolved silicon. The resulting permeate (here, the permeate after silicon removal contains calcium and magnesium ions and hardness, which is returned to the ion exchange device for further hardness removal) is returned to the ion exchange device.

[0080] Evaporation crystallization equipment is used to evaporate and crystallize the concentrated water in the electrostatic separation and concentration unit to produce salt, thereby maximizing the recovery of water resources in the wastewater. The evaporation crystallization equipment can be MVR evaporation crystallization, single-effect, double-effect, or multi-effect evaporation crystallization.

[0081] All of the above-mentioned devices can be obtained commercially available according to performance requirements. The agglomerating agent used in the integrated hardening and desiliconization device and the rapid sedimentation device for desiliconization is an inorganic mineral that has undergone sequential acid washing and positive charge modification; its particle size is 1-10 mm, and its density is 2.0-6.0 g / cm³. 3The porosity is 20-80%; the inorganic minerals are natural minerals or solid waste discharged from coal chemical industry, coal mine, and power plant, such as gasification slag, coal gangue, carbide slag, attapulgite, fly ash, and other high-density materials. In this embodiment, it can be prepared by the following method:

[0082] 1) Dispersed pretreatment of gasification slag

[0083] After evenly spreading the gasification slag, place it into a crucible, put the crucible into a muffle furnace, and dry it at 100℃ for 30 minutes. Weigh the dried gasification slag and prepare a gasification slag suspension with a mass fraction of 40%. Add sodium hexametaphosphate (wherein the mass ratio of sodium hexametaphosphate to gasification slag is 0.1:1) to it and stir at room temperature for 1 hour. After centrifugation and washing, remove the sodium hexametaphosphate and dry it in an oven at 100℃ to obtain the pretreated gasification slag for later use.

[0084] 2) Pickling

[0085] Take 100g of the gasification slag after pretreatment in step 1), prepare it into a suspension with a mass fraction of 5%, then add hydrochloric acid to it to form a suspension containing 1mol / L hydrochloric acid, stir at 60℃ for 2h, and then wash with deionized water until neutral to obtain the acid-washed suspension.

[0086] 3) Positive charge modification

[0087] Under stirring conditions, an aminosilane solution with a molar concentration of 1 mol / L was slowly added to the suspension obtained in step 2), and stirred at room temperature for 2 hours to obtain a mixed suspension.

[0088] 4) Post-processing

[0089] The mixed suspension obtained in step 3) was spray-dried at 170°C and 0.15 MPa to obtain an agglomerator.

[0090] Of course, all agglomerants prepared within the aforementioned preparation process range can be applied to the efficient removal of silica from mine water.

[0091] This invention also provides a method for efficiently removing silica from mine water, which is used in the above-mentioned method for efficiently removing silica from mine water, and the specific steps are as follows:

[0092] S1. The concentrated brine from the mine, with its pH adjusted to less than 7, enters the heterogeneous membrane unit. Impurities in the mine water (such as insoluble colloidal silica in the water and silica adsorbed on the surface of particles) are removed through the heterogeneous membrane. The produced water then enters the first-stage reverse osmosis unit.

[0093] S2. The permeate from the heterogeneous membrane unit is concentrated by the first-stage reverse osmosis unit. The permeate from the first-stage reverse osmosis unit enters the first reclaimed water tank, and the concentrate from the first-stage reverse osmosis unit enters the integrated hardness and silica removal unit for further treatment.

[0094] S3. The concentrate from the first-stage reverse osmosis unit enters the integrated hardness and silica removal unit. Through chemical reactions, hardness removal precipitation adsorption, and agglomeration adsorption, dissolved silica and hardness in the first-stage reverse osmosis concentrate are rapidly removed by precipitation. The permeate from the integrated hardness and silica removal unit enters the ion exchange unit.

[0095] S4. The water produced by the integrated hardness and silicon removal unit undergoes further hardness removal through ion exchange, ensuring stable operation of subsequent membranes and evaporation crystallization. The water produced by the ion exchange unit then enters the secondary reverse osmosis unit.

[0096] S5. The permeate from the ion exchange unit is concentrated by the secondary reverse osmosis unit. The permeate from the secondary reverse osmosis unit enters the second reclaimed water tank, and the concentrate from the secondary reverse osmosis unit enters the electro-separation and concentration unit.

[0097] S6. The concentrate from the secondary reverse osmosis unit is separated into salt ions and silicon by an electro-separation and concentration unit. The product water from the electro-separation and concentration unit enters the filtration unit, and the concentrate from the electro-separation and concentration unit enters the evaporation and crystallization unit to crystallize and recycle salt.

[0098] S7. The permeate from the electrostatic separation and concentration unit passes through a filtration unit to remove the colloidal silica that has saturated after concentration. The permeate (including the remaining dissolved silica) then enters a rapid silica removal sedimentation unit. S8. The permeate from the filtration unit undergoes chemical reaction adsorption and agglomeration adsorption to rapidly precipitate and remove dissolved silica. The settled sludge is returned to the integrated hardening and silica removal unit through charge adsorption and mesh capture to enhance the adsorption and capture effect of silica removal sedimentation. The permeate and the permeate from the integrated hardening and silica removal unit are sent together to the ion exchange unit for hardening removal and then re-enter the secondary reverse osmosis unit for recycling treatment.

[0099] Example 1

[0100] A concentrated mine brine with dissolved solids of 3068 mg / L, total hardness of 460 mg / L, and silica of 28.6 mg / L (20.6 mg / L active silica and 8.0 mg / L colloidal silica) is fed into a heterogeneous membrane unit. The heterogeneous membrane removes suspended solids (including insoluble colloidal silica and silica adsorbed on particle surfaces). The permeate from the heterogeneous membrane has a silica content of 21.3 mg / L. This permeate then enters a first-stage reverse osmosis unit, where it is concentrated four times. The permeate then enters the return flow system. Water from pool one, concentrated water, enters the subsequent integrated hardness and silica removal unit. 80 mg / L of magnesium oxide is added to adsorb dissolved silica, and 3.5 mg / L of modified coal gangue is added as a flocculant to adsorb the silica precipitate from magnesium hydroxide, efficiently removing hardness and silica from the water. The resulting water has a silica content of 15.1 mg / L and a hardness of 51 mg / L. The water from the integrated hardness and silica removal unit then enters an ion exchange unit for further hardness removal, producing water with a hardness of 0.8 mg / L. The permeate from the ion exchange resin for hardening removal enters the secondary reverse osmosis unit, where it is concentrated 5 times. The permeate then enters the second reclaimed water tank, while the concentrate enters the subsequent electro-separation and concentration unit. The secondary reverse osmosis concentrate is then separated from the silicon by the electro-separation and concentration unit. The concentrate has a TDS of 70560 mg / L and a silicon content of 5.2 mg / L, and enters the subsequent evaporation and crystallization unit to crystallize and produce salt. The permeate has a TDS of 15260 mg / L and a silicon content of 230 mg / L, and enters the heterogeneous membrane filtration unit to remove 80 mg / L of colloidal silicon that has precipitated due to the failure of the scale inhibitor. The permeate has a silicon content of 150 mg / L and enters the rapid sedimentation unit for silicon removal. 140 mg / L of magnesium oxide is added to adsorb dissolved silicon, and 6 mg / L of modified coal gangue is added as a flocculant to adsorb the silicon precipitate adsorbed by magnesium hydroxide. Rapid sedimentation is then carried out, and the sludge with a solid content of 3% is returned to the front-end integrated hardening and silicon removal unit to enhance the adsorption and capture effect of the silicon precipitate. The permeate with a silicon content of 20 mg / L is sent to the ion exchange unit for hardening removal and recycling treatment.

[0101] Comparative Example 1

[0102] The mine brine used in this comparative example has the same quality as that in Example 1, and the entire process employs a desiliconization process. Figure 2 As shown:

[0103] A concentrated mine brine with dissolved solids of 3068 mg / L, total hardness of 460 mg / L, and silica of 28.6 mg / L (20.6 mg / L active silica and 8.0 mg / L colloidal silica) was fed into an ultrafiltration membrane unit. The ultrafiltration membrane removed suspended solids (including insoluble colloidal silica and silica adsorbed on particle surfaces). The ultrafiltration membrane produced water with dissolved silica of 21.3 mg / L. This water then entered a first-stage reverse osmosis unit, where it was concentrated four times. The product water entered a reclaimed water tank, while the concentrated water entered a subsequent high-density sedimentation tank. 40 mg / L sodium hydroxide was added to adjust the pH to 11.5. Calcium hydroxide (800 mg / L) and magnesium oxide (85 mg / L) are added to remove hardness from the water, resulting in a product water hardness of 61 mg / L and a silicon content of 45 mg / L. The product water from the high-density tank enters an ion exchange unit for further hardness removal, resulting in a product water hardness of 2 mg / L. The hardness-removed product water from the ion exchange resin enters a multi-stage reverse osmosis unit, where it is concentrated 6 times. The concentrated water then enters a subsequent silicon removal sedimentation tank. In the silicon removal sedimentation tank, 20 mg / L sodium hydroxide is added to adjust the pH to 9.5, and 1525 mg / L sodium aluminate is added to remove dissolved silicon. The concentrated water has a TDS of 61123 mg / L and a silicon content of 28.5 mg / L, which then enters a subsequent evaporation and crystallization unit to crystallize and produce salt. The product water has a TDS of 523 mg / L and a silicon content of 3 mg / L, which is then returned to the recycled water tank for reuse.

[0104] It is evident that, under the same influent water quality, the concentrated water that finally enters the evaporation and crystallization process in Example 1 has a TDS of 70560 mg / L and a silica content of 5.2 mg / L, which reduces the risk of scaling in the subsequent evaporation and crystallization device. In contrast, the concentrated water that finally enters the evaporation and crystallization process in Comparative Example 1 has a TDS of 61123 mg / L and a silica content of 28.5 mg / L, which greatly increases the risk of scaling in the subsequent evaporation and crystallization device.

[0105] Example 2

[0106] A concentrated mine brine with dissolved solids of 2982 mg / L, total hardness of 503 mg / L, and silicon of 29.5 mg / L (21.8 mg / L active silicon and 7.7 mg / L colloidal silicon) is fed into a heterogeneous membrane device. The heterogeneous membrane removes suspended solids from the mine water, including insoluble colloidal silicon and silicon adsorbed on particle surfaces. The heterogeneous membrane produces permeate with silicon of 22.5 mg / L. This permeate then enters a first-stage reverse osmosis unit, where it is concentrated four times. The permeate then enters a reclaimed water tank, while the concentrated water enters a subsequent integrated hardness and silicon removal unit. 86 mg / L of magnesium oxide is added to adsorb dissolved silicon. An 8 mg / L modified coal gangue agglomerant adsorbs magnesium hydroxide to precipitate silicon, efficiently removing hardness and silicon from the water, producing water with 16.2 mg / L silicon and 62 mg / L hardness. The water from the integrated hardness and silicon removal unit enters an ion exchange unit for further hardness removal, producing water with a hardness of 1.0 mg / L. The water from the ion exchange resin hardness removal unit enters a secondary reverse osmosis unit, where it is concentrated 5 times. The water then enters a second-stage reclaimed water tank, and the concentrate enters a subsequent electrostatic osmosis concentration unit. The secondary reverse osmosis concentrate is then separated from the silicon by the electrostatic osmosis concentration unit, with a TDS of 85236 mg / L and silicon of 6.3 mg / L, before entering a subsequent evaporation and crystallization unit to crystallize and produce salt. The permeate water with TDS of 11598 mg / L and silica of 243 mg / L enters a heterogeneous membrane filtration device to remove 93 mg / L of colloidal silica that precipitates from supersaturation after the scale inhibitor fails. The permeate water with silica of 147 mg / L enters a rapid silica removal sedimentation device, where 135 mg / L of magnesium oxide is added to adsorb dissolved silica, and 5.2 mg / L of modified coal gangue agglomerate is added to adsorb the silica precipitate from magnesium hydroxide. The precipitate undergoes rapid sedimentation, and the sludge with a settling solids content of 3.5% is returned to the front-end integrated hardness and silica removal device to enhance the adsorption and capture effect of silica removal sedimentation. The permeate water with silica of 18.5 mg / L is sent to an ion exchange device for hardness removal and recycling treatment.

[0107] Example 3

[0108] A concentrated mine brine with dissolved solids of 3695 mg / L, total hardness of 416 mg / L, and silicon of 27.5 mg / L (20.6 mg / L active silicon and 6.9 mg / L colloidal silicon) is fed into a heterogeneous membrane device. The heterogeneous membrane removes suspended solids from the mine water, including insoluble colloidal silicon and silicon adsorbed on particle surfaces. The heterogeneous membrane produces permeate with silicon of 21.8 mg / L. This permeate then enters a first-stage reverse osmosis unit, where it is concentrated four times. The permeate then enters a reclaimed water tank, while the concentrated water enters a subsequent integrated hardness and silicon removal unit. 79 mg / L of magnesium oxide is added to adsorb dissolved silicon. A 3 mg / L modified coal gangue agglomerant adsorbs magnesium hydroxide to precipitate silicon, effectively removing hardness and silicon from the water. The resulting water has a silicon content of 14.6 mg / L and a hardness of 75 mg / L. The water from the integrated hardness and silicon removal unit then enters an ion exchange unit for further hardness removal, resulting in a hardness of 0.6 mg / L. The water from the ion exchange resin then enters a secondary reverse osmosis unit, where it is concentrated 5 times. The water then enters a second-stage reclaimed water tank, while the concentrate enters a subsequent electrostatic osmosis concentration unit. The secondary reverse osmosis concentrate is then further concentrated by electrostatic osmosis to separate salt ions and silicon. The concentrate has a TDS of 91568 mg / L and a silicon content of 4.9 mg / L, and then enters a subsequent evaporation and crystallization unit to crystallize and produce salt. The permeate water with a concentration of 16532 mg / L and a silica concentration of 218 mg / L enters a heterogeneous membrane filtration device to remove 73 mg / L of colloidal silica that has precipitated due to supersaturation after the scale inhibitor has failed. The permeate water with a silica concentration of 145 mg / L enters a rapid silica removal sedimentation device, where 126 mg / L of magnesium oxide is added to adsorb dissolved silica, and 5.6 mg / L of modified coal gangue agglomerate is added to adsorb the silica precipitate from magnesium hydroxide. The precipitate undergoes rapid sedimentation, and the sludge with a sedimentation solids content of 4% is returned to the front-end integrated hardness and silica removal device to enhance the adsorption and capture effect of silica removal sedimentation. The permeate water with a silica concentration of 17.6 mg / L is sent to an ion exchange device for hardness removal and recycling treatment.

[0109] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A system for efficiently removing silica from concentrated mine brine, the system comprising: It includes a heterogeneous membrane unit, a primary reverse osmosis unit, an integrated hardening and desiliconization unit, an ion exchange unit, a secondary reverse osmosis unit, an electro-separation and concentration unit, a filtration unit, a desiliconization rapid sedimentation unit, an evaporation and crystallization unit, a reclaimed water tank 1, and a reclaimed water tank 2. Among them, the heterogeneous membrane device is used to remove impurities from concentrated brine in mines; The first-stage reverse osmosis unit removes salt ions from the permeate water of the heterogeneous membrane unit to form permeate water and concentrate water. The permeate water enters the first reclaimed water tank, and the concentrate water enters the integrated hardness and silica removal unit. The integrated hardness and silicon removal device utilizes chemical reactions, hardness removal precipitation adsorption, and agglomeration adsorption to rapidly precipitate and remove dissolved silicon and hardness from the concentrate of the first-stage reverse osmosis unit; Ion exchange devices are used to remove residual hardness and residual polyvalent cations from the permeate of integrated hardness and silica removal devices; The two-stage reverse osmosis unit removes salt ions from the permeate from the ion exchange unit to form permeate and concentrate. The permeate enters the second recycling tank, and the concentrate enters the electro-separation and concentration unit. The electrostatic separation and concentration unit is used to separate salt ions and soluble silicon in the concentrate of the secondary reverse osmosis unit to form permeate and concentrate. The concentrate enters the evaporation and crystallization unit, and the permeate enters the filtration unit to remove the colloidal silicon that has been saturated and precipitated. Then it enters the silicon removal rapid sedimentation unit to remove dissolved silicon through agglomeration adsorption and rapid sedimentation. The generated sludge is returned to the integrated hardness removal and silicon removal unit after charge adsorption and mesh capture to remove dissolved silicon. The generated permeate is returned to the ion exchange unit. The effective component of the agglomerating agent used in the integrated hardening and desiliconization device and the rapid sedimentation device for desiliconization is an inorganic mineral that has undergone acid washing and positive charge modification in sequence; the particle size is 1-10 mm, and the density is 2.0-6.0 g / cm³. 3 The porosity is 20-80%; the inorganic minerals are natural minerals or solid waste discharged from coal chemical industry, coal mine and power plant.

2. The system for efficiently removing silicon from concentrated mine brine according to claim 1, characterized in that: The heterogeneous membrane device is a microfiltration or ultrafiltration level filtration device, including an inlet pump, a membrane element, a backwash pump, a cleaning pump, and a cleaning tank. The membrane core is a heterogeneous membrane with a non-woven fabric bottom layer and a flexible polymer material surface layer. The surface layer has a conical structure with small pores near the surface and large pores near the bottom layer. Its performance requirements are: water recovery rate of 80-99%, operating pressure of 0.01-10 bar, water turbidity of less than 0.01 NTU, and colloidal silica removal rate of over 90%.

3. The system for efficiently removing silicon from concentrated mine brine according to claim 2, characterized in that: The primary reverse osmosis unit includes an inlet pump, a high-pressure pump, a reverse osmosis membrane element, a cleaning water pump, a chemical cleaning water pump, and a cleaning water tank. The reverse osmosis membrane core uses an atmospheric pressure or high pressure reverse osmosis membrane, and its performance requirements are a product water recovery rate of 50%-90%, an operating pressure of 1-50 bar, and a product water TDS of less than 100 mg / L.

4. The system for efficiently removing silicon from concentrated mine brine according to claim 3, characterized in that: The integrated hardening and silicon removal device includes a first reaction tank, a second reaction tank, a settling zone, and a separation zone; Both the first and second reaction tanks are equipped with dosing pumps and agitators; the separation zone is equipped with a sludge thickening tank and a membrane filtration device. The second reaction tank and the separation zone are connected by a sludge recirculation pump, which returns the sludge from the separation zone to the second reaction tank. The incoming water first passes through the first reaction tank where it undergoes pH adjustment and precipitation reaction with sodium hydroxide or calcium hydroxide. Then it enters the second reaction tank where sodium carbonate, magnesium oxide or magnesium chloride, and a flocculant are added in sequence. First, calcium carbonate and magnesium hydroxide precipitates are produced. Then, dissolved silicon is adsorbed on the surface of magnesium hydroxide. The magnesium hydroxide precipitate with adsorbed silicon and the calcium carbonate precipitate are adsorbed on the surface of the flocculant and quickly settle to the bottom of the tank. A small number of floating particles are filtered out by a membrane filtration device. The mass ratio of magnesium oxide or magnesium chloride to dissolved silicon is 0.5-1.5:1, and the amount of agglomerant added is 1-5 mg / L.

5. The system for efficiently removing silicon from concentrated mine brine according to claim 4, characterized in that: The ion exchange device includes an inlet pump, a regenerated water pump, a resin tank, a backwash pump, and a regeneration reagent tank; wherein, the resin tank uses strong acid, weak acid, or chelated cation exchange resin.

6. The system for efficiently removing silicon from concentrated mine brine according to claim 5, characterized in that: The secondary reverse osmosis unit includes an inlet pump, a reverse osmosis membrane element, a cleaning water pump, a chemical cleaning water pump, and a cleaning water tank. The reverse osmosis membrane core uses a high-pressure membrane, and its performance requirements are: The water recovery rate is 50-90%, and the operating pressure is 5-100 bar.

7. The system for efficiently removing silicon from concentrated mine brine according to claim 6, characterized in that: The rapid sedimentation device for removing silicon includes a reaction tank 1 and a reaction tank 2. Magnesium oxide or magnesium chloride and a flocculant are added sequentially to the reaction tank 1. The reaction tank 2 consists of a sedimentation zone and a vacuum micro-negative pressure heterogeneous membrane filtration component. The sedimented sludge is returned to the front-end integrated hardness removal and silicon removal device. The produced water and the produced water from the integrated hardness removal and silicon removal device are sent to the ion exchange device for hardness removal and recycling treatment. The mass ratio of magnesium oxide or magnesium chloride to dissolved silicon is 0.5-2:1, and the amount of agglomerant added is 1-10 mg / L.

8. The system for efficiently removing silicon from concentrated mine brine according to claim 1, wherein, The method for preparing the agglomerating agent includes the following steps: 1) Preprocessing The inorganic minerals are evenly spread out and dried in a muffle furnace. The dried inorganic minerals are then taken out and prepared into an inorganic mineral suspension with a mass fraction of 10-50%. Add a dispersant to the inorganic mineral suspension and stir at room temperature for 20-60 minutes; wherein the mass ratio of dispersant to inorganic minerals is 0.1-0.6:

1. The stirred inorganic mineral suspension was centrifuged and washed to remove the dispersant, and then dried to obtain pretreated inorganic minerals for later use. 2) Pickling The pretreated inorganic minerals were prepared into a suspension with a mass fraction of 4-6% using water. Then, hydrochloric acid was added to the suspension to form a suspension containing 0.01-1 mol / L of hydrochloric acid. The suspension was stirred at 55-65 °C for 1.5-2.5 h, and then washed until neutral to obtain the acid-washed suspension. 3) Positive charge modification Under stirring conditions, a silane coupling agent solution with a molar concentration of 0.8-1.2 mol / L is slowly added to the suspension obtained in step 2), and stirred at room temperature for 1.5-2.5 h to obtain a mixed suspension; 4) Post-processing The mixed suspension obtained in step 3) was dried by spray drying to obtain an agglomerator.

9. A method for efficiently removing silicon from concentrated mine brine using the system described in claim 7, characterized in that, Includes the following steps: S1. The concentrated brine from the mine, with its pH adjusted to less than 7, enters the heterogeneous membrane unit. Impurities in the mine water are removed through the heterogeneous membrane, and the produced water enters the first-stage reverse osmosis unit. S2. The permeate from the heterogeneous membrane unit is concentrated by the first-stage reverse osmosis unit and then enters the first-stage reverse osmosis unit into the reclaimed water tank. The concentrate from the first-stage reverse osmosis unit enters the integrated hardness and silica removal unit. S3. The concentrate from the first-stage reverse osmosis unit enters the integrated hardness and silica removal unit. Through chemical reactions, hardness removal precipitation adsorption, and agglomeration adsorption, dissolved silica and hardness in the first-stage reverse osmosis concentrate are rapidly removed by precipitation. The permeate from the integrated hardness and silica removal unit enters the ion exchange unit. S4. The water produced by the integrated hardness and silicon removal unit is further de-hardened by the ion exchange unit to ensure the stable operation of the subsequent membrane and evaporation crystallization. The water produced by the ion exchange unit enters the secondary reverse osmosis unit. S5. The permeate from the ion exchange unit is concentrated by the secondary reverse osmosis unit. The permeate from the secondary reverse osmosis unit enters the second reclaimed water tank, and the concentrate from the secondary reverse osmosis unit enters the electro-separation and concentration unit. S6. The concentrate from the secondary reverse osmosis unit is separated from the salt ions and silicon by an electro-separation and concentration unit. The product water from the electro-separation and concentration unit enters the filtration unit, and the concentrate from the electro-separation and concentration unit enters the evaporation and crystallization unit to crystallize and produce salt. S7. The water produced by the electro-separation and concentration unit is filtered to remove the colloidal silica that has been saturated and precipitated after concentration. The water produced by the filtration unit then enters the silica removal rapid sedimentation unit. S8. The filtration device produces water that undergoes chemical reaction adsorption and agglomeration adsorption to quickly precipitate and remove dissolved silica. The settled sludge is then recirculated into the integrated hardening and silica removal device through charge adsorption and mesh capture to enhance the adsorption and capture effect of silica removal sedimentation. The produced water then enters the ion exchange device for hardening removal and recirculates into the secondary reverse osmosis device.

Images