Treatment system and treatment process of acid mine drainage
By leveraging the synergistic effect of tailings slurry, fly ash, and activated sludge in an acidic mine wastewater treatment system, compounds with heavy metal capture capabilities are generated. This solves the problems of complexity and high cost in existing acidic mine wastewater treatment technologies, achieving efficient heavy metal removal and water resource recycling, and reaching the goal of clean production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGDONG GUANGYE YUNLIU MINING CO LTD
- Filing Date
- 2025-07-15
- Publication Date
- 2026-05-15
AI Technical Summary
Existing technologies for treating acidic mine wastewater suffer from problems such as complex processes, high costs, difficulty in controlling reagent dosage, susceptibility to strong acids and toxic heavy metals, long processing times, and large land area requirements, making stable operation difficult.
An acidic mine wastewater treatment system is adopted, including an acidic mine wastewater equalization tank, a tailings slurry tank, a primary thickening tank, a secondary thickening tank, a sludge regeneration tank, and a sludge thickening tank. Through the synergistic effect of tailings slurry, fly ash, and activated sludge, compounds with heavy metal capture capabilities are generated using substances such as silicates, alumina, calcium oxide, and iron oxide. Combined with the microbial action of activated sludge, the adsorption and precipitation of heavy metals are achieved.
It significantly improved the removal rate of heavy metals, especially chromium, arsenic and thallium. The pH value increased from 2-3 to 6-7. The removal rate of iron, manganese and zinc reached over 95%. The SS of the treated wastewater was as low as 20-30 mg/L, realizing the recycling of water resources and clean production throughout the entire process.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of wastewater treatment, and in particular to a treatment system and process for acidic mine wastewater. Background Technology
[0002] Acidic mine wastewater (AMD) is highly acidic and polluting wastewater produced by the oxidation of sulfur-containing compounds in coal mines, other mines, or in the roof and floor slabs. The pH of acidic mine wastewater is generally 2–3, and it contains a high concentration of SO42-. 2- Concentrations can reach 1000–4000 mg·L -1 It is often accompanied by various harmful metallic pollutants such as Fe, Mn, Zn, Cd, Cr, Cu, As, and Tl. Acidic mine wastewater is a major source of heavy metal and sulfate pollution in surface water and groundwater. If large quantities of acidic mine wastewater are discharged directly without treatment, it will not only severely corrode underground metal equipment but also cause serious harm to plants, animals, and microorganisms in the natural environment, posing a significant threat to the ecological environment. Therefore, the treatment of acidic mine wastewater in coal mines is urgently needed.
[0003] Currently, commonly used methods for treating acidic mine wastewater include physicochemical and biological methods. Physicochemical methods require large amounts of reagents and aeration, and are generally characterized by complex processes, high costs, and difficulty in controlling reagent dosage. Biological methods are susceptible to strong acids and toxic heavy metals (such as Fe, Mn, Zn, As, Cd, and Tl), and suffer from problems such as long processing times, susceptibility to clogging, and large land area requirements, making stable operation difficult. Therefore, researching new materials and processes for treating acidic mine wastewater has significant theoretical and practical implications for its treatment. Summary of the Invention
[0004] The purpose of this invention is to provide a treatment system and process for acidic mine wastewater to solve the problems in the background art.
[0005] To achieve the above objectives, the present invention provides a treatment system for acidic mine wastewater, comprising an acidic mine wastewater equalization tank, a tailings slurry tank, a primary thickening tank, a secondary thickening tank, a sludge regeneration tank, and a sludge thickening tank. The acidic mine wastewater equalization tank is connected to the inlet of the primary thickening tank via an acid water pump. The tailings slurry tank is connected to the primary thickening tank via a tailings slurry pump. The outlet of the primary thickening tank is connected to the secondary thickening tank. The sludge inlet of the secondary thickening tank is connected to the sludge thickening tank via an activated sludge pump. The sludge inlet of the sludge regeneration tank is connected to the sludge outlet of the secondary thickening tank, and the sludge outlet of the sludge regeneration tank is connected to the sludge inlet of the sludge thickening tank. The chemical inlet of the primary thickening tank is connected to a fly ash dosing pump.
[0006] Preferably, the sludge outlet of the primary thickening tank is connected to the tailings dam via a sludge pump, and the water inlet of the primary thickening tank is connected to the supernatant discharge outlet of the sludge thickening tank.
[0007] Preferably, the outlet of the secondary thickening tank is connected to the recycled water tank, and the sludge outlet of the secondary thickening tank is connected to the sludge regeneration tank.
[0008] Preferably, both the primary thickener and the secondary thickener have a double-helix high-efficiency thickening structure, and both are equipped with a vortex tube in the middle, including an inner ring and an outer ring, which can quickly and powerfully mix fly ash, tailings slurry, acidic mine wastewater and sludge thickener supernatant, or quickly and powerfully mix activated sludge and primary thickener overflow, and quickly throw large particles into the thickener sludge hopper.
[0009] This invention, based on an acidic mine wastewater treatment system, proposes a method for treating acidic mine wastewater, comprising the following steps:
[0010] S1. Tailings slurry, fly ash and acidic mine wastewater are simultaneously added to a primary thickening tank for vigorous mixing and centrifugal separation.
[0011] S2. The bottom sludge after sedimentation in the primary thickening tank enters the tailings dam, and the supernatant enters the secondary thickening tank. At the same time, the activated sludge from the sludge thickening tank is added to the secondary thickening tank, mixed and stirred, and then centrifuged.
[0012] S3. The supernatant after sedimentation enters the reclaimed water tank, and the bottom sludge enters the sludge regeneration tank for regeneration. The regenerated sludge enters the sludge thickening tank. After thickening, part of the sludge is discharged to the tailings pond, and part of it is recycled back into the secondary thickening tank. The supernatant of the sludge thickening tank enters the primary thickening tank for recycling.
[0013] Preferably, in S1, the tailings slurry is a mixture of solid and waste discharged after the concentrate is removed in the mineral processing process. The main solid components in the tailings slurry are 50% to 70% SiO2, 5% to 10% Al2O3, 5% to 10% S, 5% to 15% Fe and 0% to 5% C.
[0014] Fly ash is the ash residue after coal combustion in boilers. Its main components are 50-80% SiO2, 5-10% Al2O3, 5-15% iron oxide and 3-40% calcium oxide.
[0015] Preferably, in S1, the ratio of tailings slurry, fly ash and acidic mine wastewater is (20-50):(20-30):100.
[0016] Preferably, in step S2, the activated sludge has a water content of 95-97%, originates from waste in the sewage treatment process of the mining area, and its main components are microorganisms and their metabolites.
[0017] Preferably, in step S2, the ratio of activated sludge to acidic mine wastewater is 1:5.
[0018] Preferably, the hydraulic retention time of the sludge regeneration tank is 4-12 hours and the SRT is 20-30 days. Its operating conditions can be set according to the different microorganisms to be domesticated by the pollutants to be removed, and the aerobic / anoxic time can be set. After sludge regeneration, the supernatant and effective components are returned to the primary thickening tank to catalyze the oxidation and removal of some heavy metal pollutants in the acidic water.
[0019] Therefore, the acidic mine wastewater treatment system and process of the present invention have the following beneficial effects:
[0020] (1) This invention utilizes the main components of tailings slurry and fly ash, such as silicates, alumina, calcium oxide, and iron oxide, to undergo neutralization and silicate reactions, generating silicate compounds with heavy metal capture capabilities. These compounds adsorb and precipitate heavy metals such as iron, manganese, zinc, lead, arsenic, chromium, and thallium in acidic mine wastewater, generating Al 3+ Fe 3+ MnO2 and other substances have catalytic, adsorption, and co-precipitation effects on many heavy metals. The supernatant after precipitation enters a secondary thickening tank, where it is mixed with activated sludge and then precipitated again. Microorganisms in the activated sludge utilize extracellular polymers to adsorb residual manganese, arsenic, chromium, and thallium from the overflow liquid. Some functional microorganisms utilize chemoenergetic processes and endogenous respiration to remove SO42-. 2- Cr 6+ After reduction, it produces elemental S or S2. 2- and Cr 3+ S 2- Cr forms a precipitate with metals. 3+ It can be adsorbed by microorganisms or form precipitates. The bottom sludge of the primary thickening tank is quickly solidified and directly discharged into the tailings dam. The bottom sludge generated in the secondary thickening tank can be regenerated and concentrated in the regeneration tank, and then part of it is recycled and part of it is discharged. This system can significantly improve the removal rate of toxic heavy metals chromium, arsenic and thallium in acidic mine wastewater. Its pH can be increased from 2-3 to 6-7. The removal rate of iron, manganese and zinc is as high as 95% or more, and the removal rate of hexavalent chromium, pentavalent arsenic and thallium can reach more than 70%. The SS of the treated wastewater is as low as 20-30 mg / L, which can meet the production requirements of mineral processing.
[0021] (2) The raw materials used in this invention are entirely derived from solid waste in the factory area, including tailings slurry from mineral processing, activated sludge from domestic sewage treatment processes, and fly ash from boiler rooms, thus achieving waste treatment with waste.
[0022] (3) The system protected by this invention constructs a sludge and supernatant circulation loop: after the bottom sludge of the secondary thickening tank enters the sludge regeneration tank, the activated sludge is regenerated, concentrated, and precipitated before being returned to the secondary thickening tank for recycling, reducing the amount of sludge discharged; the supernatant of the sludge thickening tank is returned to the primary thickening tank, where organic matter and heavy metals in the sludge supernatant recombine and react with acidic mine wastewater, tailings slurry, and fly ash in the primary thickening tank, realizing the reuse of water resources and active ingredients, significantly improving the heavy metal removal rate, and reducing the amount of pollutants discharged. In addition, the bottom sludge of the primary thickening tank (mainly suspended solids in tailings slurry and fly ash, and precipitates generated by the reaction with acidic mine wastewater and the supernatant of the sludge thickening tank) is discharged into the tailings pond for unified disposal, avoiding the problem of separate treatment of traditional chemical sludge and realizing clean production throughout the entire process.
[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the system structure according to an embodiment of the present invention;
[0025] Figure label:
[0026] 1. Tailings slurry pond; 2. Fly ash; 3. Tailings slurry pump; 4. Fly ash dosing pump; 5. Acidic mine wastewater regulating pond; 6. Acid water pump; 7. Primary thickening pond; 8. Sludge regeneration pond; 9. Activated sludge; 10. Secondary thickening pond; 11. Reclaimed water pond; 12. Activated sludge pump; 13. Sludge pump; 14. Tailings dam; 15. Sludge thickening pond. Detailed Implementation
[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, but not all embodiments.
[0029] Example
[0030] like Figure 1As shown, the present invention provides a treatment system for acidic mine wastewater, including an acidic mine wastewater equalization tank 5, a tailings slurry tank 1, a primary thickening tank 7, a secondary thickening tank 10, a sludge regeneration tank 8, and a sludge thickening tank 15. The acidic mine wastewater equalization tank 5 is connected to the primary thickening tank 7 via an acid water pump 6. The tailings slurry tank 1 is connected to the primary thickening tank 7 via a tailings slurry pump 3. The outlet of the primary thickening tank 7 is connected to the secondary thickening tank 10. The sludge inlet of the secondary thickening tank 10 is connected to the sludge thickening tank 15 via an activated sludge pump 12. The sludge inlet of the sludge regeneration tank 8 is connected to the sludge outlet of the secondary thickening tank 10, and the sludge outlet of the sludge regeneration tank 8 is connected to the sludge inlet of the sludge thickening tank 15.
[0031] The inlet of the primary thickener 7 is connected to the fly ash dosing pump 4; the sludge outlet of the primary thickener 7 is connected to the tailings dam 14 via the sludge pump 13; the water inlet of the primary thickener 7 is connected to the supernatant discharge outlet of the sludge thickening tank 15; the water outlet of the secondary thickener 10 is connected to the reclaimed water tank 11; the sludge outlet of the secondary thickener 10 is connected to the sludge regeneration tank 8; both the primary thickener 7 and the secondary thickener 10 have a double-vortex high-efficiency thickening structure, and a vortex tube is set in the middle, adopting the structure of the prior art, wherein the vortex tube has an inner ring and an outer ring, including a central shaft, an inner ring and an outer ring arranged sequentially around the central shaft, the central shaft is connected to the inner ring, and the inner ring is connected to the outer ring. The inner ring is an inverted conical steel inner ring with an inverted cone angle of 15°. The inner ring of the primary thickener 7 is provided with inlets for slurry, acid water, fly ash 2 and supernatant from the sludge thickening tank 15. After centrifugal grading in the inner and outer rings, the above mixture is rapidly mixed, concentrated, and settled. The overflow liquid, after grading by centrifugal action in both rings, reaches a relatively stable dispersion and enters the thickening tank for further concentration and sedimentation. The central axis of the cyclone device is connected to both the inner and outer rings and leads to the sludge hopper. Mine wastewater, fly ash, and tailings slurry are mixed in a certain proportion and then enter the primary thickening tank tangentially. The inner ring rotates, generating centrifugal force. The inner ring extends below the surface of the mixed liquid. Using centrifugal force, the tailings slurry, fly ash 2, acid water, and supernatant from the sludge thickening tank 15 are thoroughly mixed and preliminarily graded. The sediment can then settle directly along the central axis, reducing the impact of sediment in the inner ring on the external mixed liquid and improving the sedimentation effect. The overflow portion is relatively stable and dispersed into the outer ring for secondary centrifugal classification. After two centrifugal classifications in the inner and outer rings, the suspended solids and precipitates generated in the slurry, fly ash, acid water, and supernatant of the thickener are concentrated and settled. The overflow liquid after classification by centrifugation in the inner and outer rings will reach a relatively stable state and disperse into the thickener for further settling, thus improving the settling efficiency.
[0032] The inner ring of the secondary thickening tank 10 is equipped with an activated sludge inlet and an overflow inlet of the primary thickening tank 7, while the rest is the same as the primary thickening tank. The dual vortex device of the above two can rapidly and powerfully mix fly ash 2, tailings slurry, acidic mine wastewater and supernatant from the sludge thickening tank, or rapidly and powerfully mix activated sludge 9 and the overflow from the primary thickening tank 7, and quickly throw large particles into the sludge hopper.
[0033] The sludge regeneration tank 8 is connected to the sludge hopper of the secondary thickening tank 10 at the front end and to the sludge inlet of the sludge thickening tank 15 at the rear end. The regeneration tank is equipped with an aeration device, a feed inlet, and a low-speed stirring device. The microporous aeration device is located at the bottom of the regeneration tank and is connected to a blower through an air pipe to oxidize or anaerobically regenerate the activated sludge (selected according to the type of pollutants and microorganisms). The aerobic / anoxic time is set according to the type of pollutants in the acidic water to acclimate different microorganisms, and the SRT is set to 20-30 days. The supernatant outlet of the sludge thickening tank 15 is connected to the primary thickening tank 7 through a supernatant pump. After mixing with fly ash 2, tailings slurry, and acidic mine wastewater, it enters the double cyclone thickening device of the primary thickening tank 7. One end of the sludge discharge port is connected to the intermediate cyclone tank of the secondary thickening tank 10 through a return pump 12, and the other end is connected to the tailings dam 14 through a residual sludge pump. The acidic mine wastewater is treated using the above treatment system. The specific steps are as follows:
[0034] S1. Pump the acidic mine wastewater into the primary thickening tank 7 at a volumetric flow rate of 1000 m³ / h. 3 / h, simultaneously add tailings slurry (addition amount is 500m³). 3 / h), fly ash 2 (addition amount is 200m³) 3 / h), supernatant from the thickener (dosage 400m³) 3 The sludge is mixed in the primary thickening tank 7 (at a certain time). The double-vortex agitator is activated, and the vortex cylinder generates a centrifugal force field, causing large particles to settle rapidly into the sludge hopper. The primary thickening tank has a designed diameter of 60m, a water depth of 2.5m, and a bottom slope of 0.15. It is equipped with one peripheral-driven heavy-duty thickener. Three sludge pumps are installed in the bottom pump station, with a sludge discharge capacity of 400m³ / h. 3 / h, the sludge is transported to the tailings dam in the plant area by the sludge pump at the bottom of the pool. During this process, the main components of the tailings slurry and fly ash 2, such as silicates, alumina, calcium oxide and iron oxide, undergo neutralization and silicate reactions to generate silicate compounds with heavy metal capture capabilities, which adsorb and precipitate heavy metals such as iron, manganese, zinc and lead in acidic mine wastewater.
[0035] S2. After sedimentation in the primary thickening tank, the bottom sludge is discharged into the tailings dam 14 via sludge pump 13; the supernatant (1700m³) 3 / h) flows by gravity into the secondary thickening tank 10 (D=60m, effective water depth 2.5m; secondary thickening tank bottom sediment (800m) 3The activated sludge mixture ( / h) enters the sludge regeneration tank 8. The activated sludge mixture in the sludge regeneration tank 8 (dimensions: 5.3m*50m*24m, air-to-water ratio: 5:1, sludge retention time: 6h) is introduced into the sludge regeneration tank 8. 3 The sludge enters the sludge thickening tank 15 at a flow rate of / h for thickening. The sludge thickening tank is a radial flow thickening tank (D=64m, effective water depth is 4m). After thickening, the sludge is pumped by activated sludge pump 12 at a flow rate of 300m³ / h. 3 A volumetric flow rate of / h was simultaneously added to the secondary thickener 10, mixed, and then centrifuged; the supernatant was then centrifuged at a flow rate of 400m³ / h. 3 A volumetric flow rate of / h is returned to the primary thickening tank. During this process, the EPS in activated sludge 9 adsorbs and sweeps away colloidal substances and suspended metal ions from the supernatant of the primary thickening tank. The microorganisms and carbon source in activated sludge 9 convert high-valence hexavalent chromium and pentavalent arsenic into low-toxicity trivalent chromium and trivalent arsenic. The remaining sludge discharge is 100m³. 3 / h.
[0036] S3. The supernatant after sedimentation in the secondary thickening tank enters the recycled water tank 11 and is pumped into the mineral processing and other water-using processes by a water pump. The bottom sludge enters the sludge regeneration tank 8 for aeration oxidation / reduction regeneration. The sludge mixture in the sludge regeneration tank 8 flows to the sludge thickening tank 15. The sludge thickened and regenerated in the sludge thickening tank 15 is recycled back into the secondary thickening tank 10 by the sludge return pump 12. The supernatant in the sludge thickening tank 15 is recycled into the primary thickening tank 7 by the supernatant pump. The remaining sludge in the sludge thickening tank flows into the tailings dam 14 by the remaining sludge pump.
[0037] The influent and effluent water quality and treatment performance of acidic mine wastewater are shown in Table 1.
[0038] Table 1 Typical influent and effluent water quality (mg / L, except pH value)
[0039]
[0040] In the above treatment process, the main components of tailings slurry and fly ash, such as silicates, alumina, calcium oxide, and iron oxide, undergo neutralization and silicate reactions, as follows:
[0041] CaO + 2H+ + →Ca 2+ +H2O;
[0042] Fe2O3+6H + →2Fe 3+ +3H2O;
[0043] Fe3O4+8H + →2Fe 3+ +Fe 2++4H2O;
[0044] Al₂O₃ + 6H₂O + →2Al 3+ +3H2O;
[0045] 2H + +2Na₂SiO₃→H₂SiO₃↓+2Na + :
[0046] H + +NaAlSi3O8+7H2O→Al(OH)3+3H4SiO4↓+Na + ;
[0047] H4SiO4→H3SiO3↓+H2O→SiO2↓+2H2O;
[0048] Subsequently, silicate compounds such as H4SiO4, H3SiO3, SiO2, and Al(OH)3, which have the ability to capture heavy metals, are generated. These compounds adsorb and precipitate heavy metals such as iron, manganese, zinc, lead, arsenic, chromium, and thallium in acidic mine wastewater. The specific reactions are as follows:
[0049] Zn 2+ +2Na₂SiO₃→ZnSiO₃↓+2Na + ;
[0050] Fe 2+ +2Na₂SiO₃→FeSiO₃↓+2Na + ;
[0051] Mn 2+ +2Na₂SiO₃→MnSiO₃↓+2Na + ;
[0052] Cr 3+ +3NaSiO3→Cr2(SiO3)3↓+6Na + ;
[0053] The supernatant after sedimentation enters a secondary thickening tank, where it is mixed with activated sludge and then settled. Microorganisms in the activated sludge utilize extracellular polymers to adsorb residual manganese, arsenic, chromium, and thallium from the overflow. Some functional microorganisms utilize chemoenergetic processes and endogenous respiration to remove SO42-. 2- Cr 6+ After reduction, it produces elemental S or S2. 2- and Cr 3+ S 2- Cr forms a precipitate with metals. 3+ It can be adsorbed by microorganisms or form precipitates. Fe in the regeneration tank 2+ Mn 2+ As 3+ TI+ A redox reaction occurs to produce Fe. 3+ MnO2 and As 5+ It also triggers a reaction in the regeneration tank to generate Ca3(AsO4)2, FeAsO4, and Ti. 3+ TI2O3, TI 3+ The supernatant from the thickener is refluxed back to the primary thickener, triggering a reaction in the primary thickener to generate Ti2(SiO3)3. The specific reactions involved are as follows:
[0054] H2Cr2O7+6FeSO4→Cr2(SO4)3↓+3Fe2(SO4)3+7H2O;
[0055] AsO3 3- +1 / 2O2→AsO4 3- ;
[0056] 2AsO4 3- +3Ca 2+ →Ca3(AsO4)2;
[0057] AsO4 3- +Fe 3+ →FeAsO4↓;
[0058] 2TI + +2MnO2+2H2O→TI2O3↓+2Mn 2+ +2OH - ;
[0059] 2TI 3+ +3NaSiO3→TI2(SiO3)3↓+6Na + .
[0060] Comparative Example
[0061] This comparative example uses traditional methods for treating acidic mine wastewater, namely the conventional lime neutralization method or the high-density slurry method. The main neutralizing agents used are lime and flocculant PAM. The process involves simultaneous neutralization and aeration oxidation, followed by flocculation and sedimentation using the added flocculant, thereby removing Fe ions. 2+ Mn 2+ and Zn 2+ The following reactions occurred:
[0062] Ca(OH)2+H2SO2→CaSO4·2H2O↓+H2O;
[0063] MeSO4+Ca(OH)2→CaSO4·2H2O↓+Me(OH)2;
[0064] 2Fe 2+ +1 / 2O2+2H+ →2Fe 3+ +H2O;
[0065] Mn 2+ +1 / 2O₂ + H₂O → MnO₂↓ + OH⁻ - .
[0066] The above-described embodiments and comparative examples show that the water treated with these methods can achieve the same treatment effect for metals such as iron, manganese, and zinc. However, the removal rate of other heavy metals such as arsenic, chromium, and thallium is relatively low. In this embodiment, the neutralizing agent lime and the flocculant PAM were not used, which reduces the cost compared to traditional methods and significantly improves the removal capacity of heavy metals such as arsenic, chromium, and thallium. Secondly, in the comparative example, the traditional method directly discharges the treated water, while in this embodiment, the treated water is applied to other mineral processing processes, saving a large amount of clean water.
[0067] Therefore, the present invention provides a treatment system and process for acidic mine wastewater, which utilizes tailings slurry from pyrite beneficiation process in conjunction with fly ash and activated sludge to treat acidic mine wastewater. This process can simultaneously remove heavy metals, thereby achieving the goal of resource utilization of acidic mine wastewater, improving water utilization efficiency, protecting the ecological environment of the mining area, and realizing safe and green production in the mine.
[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A treatment method for an acidic mine wastewater treatment system, characterized in that: The treatment system includes an acidic mine wastewater equalization tank, a tailings slurry tank, a primary thickening tank, a secondary thickening tank, a sludge regeneration tank, and a sludge thickening tank. The acidic mine wastewater equalization tank is connected to the inlet of the primary thickening tank via an acid water pump. The tailings slurry tank is connected to the primary thickening tank via a tailings slurry pump. The outlet of the primary thickening tank is connected to the secondary thickening tank. The sludge inlet of the secondary thickening tank is connected to the sludge thickening tank via an activated sludge pump. The sludge inlet of the sludge regeneration tank is connected to the sludge outlet of the secondary thickening tank, and the sludge outlet of the sludge regeneration tank is connected to the sludge inlet of the sludge thickening tank. The sludge regeneration tank is connected to the sludge hopper of the secondary thickening tank at the front end and to the sludge inlet of the sludge thickening tank at the rear end. The sludge regeneration tank is equipped with an aeration device, a feed inlet and a low-speed stirring device. The microporous aeration device is set at the bottom of the sludge regeneration tank and is connected to the blower through an air pipe to oxidize or anaerobic regenerate the activated sludge. The aerobic / anoxic time is set according to the type of pollutants in the acid water and the different microorganisms are domesticated. The inlet of the primary thickening tank is connected to the fly ash dosing pump. Both the primary thickening tank and the secondary thickening tank have a double-helix thickening structure, and both are equipped with a double-ring vortex tube in the middle. The processing method includes the following steps: S1. Tailings slurry, fly ash, and acidic mine wastewater are simultaneously added to the double-helix thickening structure of the primary thickening tank for mixing and centrifugal separation; the ratio of tailings slurry, fly ash, and acidic mine wastewater is 20~50:20~30:100; the tailings slurry is a mixture of solid and waste discharged after the concentrate is removed in the mineral processing, and its main components are 50%~70% SiO2, 5~10% Al2O3, 5~10% S, 5~15% Fe, and 0~5%... C; Fly ash is the ash residue after coal combustion in boilers, and its main components are 50-80% SiO2, 5-10% Al2O3, 5-15% iron oxide and 3-40% calcium oxide; In this process, the main components of tailings slurry and fly ash, such as silicon dioxide, aluminum oxide, calcium oxide and iron oxide, undergo neutralization and silicate reaction to generate silicate compounds with heavy metal capture capabilities, which adsorb and precipitate heavy metals such as iron, manganese, zinc, lead, arsenic, chromium and thallium in acidic mine wastewater; S2. The bottom sludge after sedimentation in the primary thickening tank enters the tailings dam, and the supernatant enters the secondary thickening tank. At the same time, the activated sludge in the sludge thickening tank is added to the secondary thickening tank. After mixing, the mixture is centrifuged. The water content of the activated sludge is 95-97%. The ratio of activated sludge to acidic mine wastewater is 1:
5. In this process, the EPS in the activated sludge adsorbs and sweeps colloidal substances and suspended metal ions in the supernatant of the primary thickening tank of the tailings slurry. The microorganisms and carbon sources in the activated sludge convert the high-valence state of hexavalent chromium and pentavalent arsenic into the low-toxicity state of trivalent chromium and trivalent arsenic. S3. The supernatant from the secondary thickener enters the reclaimed water tank and is pumped into the mineral processing and other water-using stages. The bottom sludge enters the sludge regeneration tank for aeration oxidation / reduction regeneration. The sludge mixture in the sludge regeneration tank flows to the sludge thickener. The sludge thickened and regenerated in the sludge thickener is pumped back into the secondary thickener for recycling. The supernatant in the sludge thickener is pumped into the primary thickener for recycling. The remaining sludge in the sludge thickener flows into the tailings pond via the excess sludge pump. The hydraulic retention time in the sludge regeneration tank is 4-12 hours, and the sludge retention time is 20-30 days. Fe in the regeneration tank... 2+ Mn 2+ As 3+ TI + A redox reaction occurs to produce Fe. 3+ MnO2 and As 5+ It also triggers a reaction in the regeneration tank to generate Ca3(AsO4)2, FeAsO4, and Ti. 3+ TI2O3, TI 3+ The supernatant from the concentration tank is returned to the primary concentration tank, triggering a reaction in the primary concentration tank to generate TI2(SiO3)3.
2. The treatment method of the acidic mine wastewater treatment system according to claim 1, characterized in that: The sludge outlet of the primary thickening tank is connected to the tailings dam via a sludge pump, and the water inlet of the primary thickening tank is connected to the supernatant discharge outlet of the sludge thickening tank.
3. The treatment method of the acidic mine wastewater treatment system according to claim 1, characterized in that: The outlet of the secondary thickening tank is connected to the recycled water tank.