Industrial waste recycling for acid mine drainage treatment system and treatment method

Abstract

The application discloses an industrial waste recycling system for acid mine water treatment and a treatment method, and belongs to the technical field of acid mine water treatment. The system comprises a tailing slurry, an acid water adjusting tank, a first thickening tank, a second thickening tank and a tailing pond. The tailing slurry is connected with the first thickening tank through a tailing slurry pump. The acid water adjusting tank is connected with the first thickening tank through a water inlet pump. The liquid outlet of the first thickening tank is connected with the second thickening tank. The mud outlets of the first thickening tank and the second thickening tank are connected with the tailing pond. The system is used for treating acid mine water. The application utilizes the concept of "waste treatment with waste" to treat acid mine water, reduces the treatment cost of tailings and acid mine wastewater, saves the water supplement and the amount of acid reagent added in the recycling process (mineral processing technology), and purifies various iron, manganese and zinc pollutants in the process, thereby reducing the discharge of pollutants in the whole process.

Description

Technical Field

[0001] This invention relates to the field of acidic mine water treatment, and in particular to an industrial waste recycling system and treatment method for acidic mine water. Background Technology

[0002] Acidic mine water is one of the main pollutants generated during mining operations. Rich in sulfuric acid, heavy metal ions such as iron and manganese, and suspended solids, its direct discharge without treatment will lead to water acidification, soil degradation, and ecosystem damage, seriously threatening the safety of the surrounding environment and human health. Currently, traditional treatment methods for acidic mine water mainly include lime neutralization and precipitation, oxidation-reduction, iron filings replacement, electrolysis, adsorption, wetland methods, lime ditch methods, permeable reactive barrier methods, and biological sulfidation, but these methods have significant drawbacks.

[0003] Adsorption, iron filings replacement, and biological sulfidation methods can only remove heavy metals from wastewater; wetland methods can remove heavy metals and some sulfates simultaneously, but have long retention times and require large areas; adsorption, oxidation-reduction, lime ditch methods, and permeable reactive barriers require frequent material replacement and also have long retention times; chemical neutralization precipitation requires continuous addition of alkaline agents to adjust the pH value, which is costly and easily produces a large amount of neutralization slag with high water content and difficult treatment; electrolysis consumes too much electricity. In addition, the treated wastewater is mostly discharged directly, failing to achieve water resource recycling, which contradicts the water conservation and energy saving requirements of the mining industry; and the tailings slurry (rich in fine-grained minerals, residual agents, and heavy metals) and acidic mine water generated during mineral processing are mostly treated separately, without forming a waste-integrated disposal mechanism, resulting in a continuous increase in tailings dam accumulation, posing a risk of dam failure and heavy metal migration pollution.

[0004] Based on the above problems, how to achieve the synergistic treatment of acidic mine water and tailings slurry through process innovation, and simultaneously solve the problems of water pollution control, waste disposal and water resource reuse, has become a technical bottleneck that needs to be overcome for the green development of mines. Summary of the Invention

[0005] The purpose of this invention is to provide an industrial waste recycling system and treatment method for acidic mine water, in order to solve the problems in the background art.

[0006] To achieve the above objectives, the present invention provides an industrial waste recycling system for acidic mine water treatment, comprising tailings slurry, an acid water conditioning tank, a primary thickening tank, a secondary thickening tank, and a tailings dam. The tailings slurry is connected to the primary thickening tank via a tailings slurry pump, the acid water conditioning tank is connected to the primary thickening tank via an inlet pump, the outlet of the primary thickening tank is connected to the secondary thickening tank, and the sludge outlets of both the primary and secondary thickening tanks are connected to the tailings dam.

[0007] Preferably, the outlet of the secondary thickening tank is connected to the recycled water tank; both the primary and secondary thickening tanks have a dual-vortex concentration and dewatering structure.

[0008] Preferably, the outlet of the tailings dam is connected to an overflow well, and the outlet of the overflow well is connected to a sewage treatment plant.

[0009] Based on the above-mentioned treatment system, this invention proposes a method for recycling industrial waste into acidic mine water, comprising the following steps:

[0010] S1. The mine wastewater in the acid water conditioning tank is mixed with the tailings slurry in the mineral processing line and then enters the primary thickening tank for centrifugal separation and sedimentation.

[0011] S2. The sludge after sedimentation in the primary thickening tank enters the tailings dam, and the supernatant after sedimentation enters the secondary thickening tank for secondary centrifugal separation and sedimentation.

[0012] S3. After the secondary centrifugal separation and sedimentation are completed, the supernatant enters the return water tank for reuse in the mineral processing process, and the sludge enters the tailings dam.

[0013] S4. The supernatant in the tailings dam overflows through the overflow well to the sewage treatment plant for treatment. After treatment, the tailings are discharged into the discharge outlet.

[0014] Preferably, in S1, the tailings slurry comes from waste tailings sand from the pyrite beneficiation plant.

[0015] Preferably, the water content of the solid component tailings sand in the tailings slurry is 10-20%, and the tailings sand includes 3-10% S, 5-10% Fe, 40-60% SiO2, 0-5% Al2O3 and 2-5% organic carbon.

[0016] Preferably, in step S1, the pH of the tailwater in the acid water adjustment tank is 2 to 3.

[0017] Preferably, in S1, the hydraulic retention time of the primary thickening tank is 4 to 6 hours, and the swirling velocity is 0 to 3500 r / min.

[0018] Preferably, in step S2, the hydraulic retention time of the secondary thickener is 4 to 6 hours, and the swirling velocity is 0 to 3500 r / min.

[0019] Preferably, in step S4, the pH of the overflow water flowing into the wastewater treatment plant is greater than 6.

[0020] Preferably, in step S4, the wastewater treatment plant includes a pH adjustment tank, an oxidation tank, a coagulation tank, a flocculation tank, a sedimentation tank, a pH adjustment tank, and a discharge outlet.

[0021] Preferably, in step S4, the tailings slurry can not only neutralize the acidic mine wastewater, but also react with the heavy metals iron, manganese and zinc therein to precipitate; the acidic mine wastewater treated by this process can be reused in most water-using stages of the mineral processing process, and the quality of the concentrate is not affected.

[0022] Therefore, the present invention provides an industrial waste recycling system and treatment method for acidic mine water, which has the following beneficial effects:

[0023] (1) The method protected by this invention uses existing solid waste tailings slurry as a neutralizing agent and heavy metal removal agent without the use of neutralizing agents and flocculants. It utilizes the main components of the tailings slurry, silicates, Al2O3, Fe2O3 and Fe3O4, to form water-rock and neutralization reactions, and to form ion exchange, hydrolysis reaction, co-precipitation, sweeping capture, adsorption and neutralization with other metal ions and colloids. The treated acidic mine wastewater is directly reused for sulfur concentrate beneficiation, which can reduce the addition of sulfuric acid and the use of clean water, and reduce the content of iron, manganese and other heavy metals in the acidic mine wastewater, which also has a significant impact on the reduction of heavy metal concentration in the beneficiation process. At the same time, it achieves the recycling of wastewater and reduces the disposal costs of tailings slurry and acidic mine wastewater.

[0024] (2) The tailings slurry used in this invention has a high content of silicates, iron oxides and alumina. After the tailings slurry is mixed with acid water, it is directly reacted with H in the acid water. + and Fe 2+ Mn 2+ and Zn 2+ The process involves dilution, neutralization, and metal precipitation. The metal silicate precipitates form crystals that act as nuclei with the residual particulate tailings, forming a combined effect of co-precipitation, sweeping capture, and adsorption with metal ions and other colloids. This significantly improves the morphology of the precipitate and the amount of sediment at the bottom, greatly increases the sedimentation rate, accelerates settling, and achieves the triple effects of neutralization, removal of metal ions, and removal of suspended solids.

[0025] (3) Traditional methods require neutralization oxidation, flocculation, sedimentation tanks, and reclaimed water tanks. In this invention, after the tailings slurry is mixed with acidic mine wastewater, a primary thickening tank is used to achieve preliminary separation of mud and water. The sludge is directly stored in the tailings dam, avoiding the energy consumption and equipment investment of traditional tailings slurry concentration, and reducing the amount of sludge generated from acidic mine wastewater treatment. The primary thickening tank quickly removes suspended solids and some heavy metal ions (such as Fe) from the acidic mine wastewater through the flocculation of fine tailings slurry particles. 2+ Mn 2+The secondary thickening tank further reduces the turbidity of the supernatant and stabilizes the pH value at 6.0-7.5 through static sedimentation and the synergistic effect of residual reagents, fully meeting the water quality requirements of the mineral processing process for recycled water (such as the strict restrictions on turbidity and ion concentration in the flotation process). The treated supernatant is directly reused in the mineral processing process to replace fresh water, thereby improving the recycling rate of water resources in the mining area.

[0026] 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

[0027] Figure 1 This is a system schematic diagram according to an embodiment of the present invention;

[0028] Figure 2 This is a process flow diagram of a wastewater treatment plant according to an embodiment of the present invention;

[0029] Figure label:

[0030] 1. Acid water conditioning tank; 2. Inlet pump; 3. Tailings slurry pump; 4. Primary thickening tank; 5. Secondary thickening tank; 6. Reclaimed water tank; 7. Tailings dam; 8. Overflow well; 9. Wastewater treatment plant; 10. Discharge outlet. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] 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.

[0033] Example

[0034] like Figures 1-2 As shown, the present invention provides an industrial waste recycling system for acid mine water treatment, including tailings slurry, acid water conditioning tank 1, primary thickening tank 4, secondary thickening tank 5 and tailings dam 7. The tailings slurry is connected to the primary thickening tank 4 through a tailings slurry pump 3, and the acid water conditioning tank 1 is connected to the primary thickening tank 4 through an inlet pump 2. The tailings slurry and acid mine water enter the primary thickening tank together for mixing and reaction treatment.

[0035] The outlet of the primary thickener 4 is connected to the secondary thickener 5, and the supernatant from the primary thickener enters the secondary thickener for further reaction. The sludge outlets of both the primary thickener 4 and the secondary thickener 5 are connected to the tailings dam 7. The outlet of the secondary thickener 5 is connected to the recycled water tank 6 for reuse. Both the primary thickener 4 and the secondary thickener 5 have a double-vortex high-efficiency thickening device, which is existing technology. This device includes a central shaft and inner and outer rings 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°, and it is equipped with inlets for acidic mine wastewater and slurry. After centrifugal classification by the inner and outer rings, the mixture of acidic mine wastewater and slurry is first concentrated and settled. The overflow slurry, after classification by centrifugal action of the inner and outer rings, reaches a relatively stable dispersion and enters the thickener for further concentration and settling. The central axis of the cyclone device is connected to both the inner and outer rings, leading to the sludge hopper of the thickening tank. Mine wastewater and tailings slurry are mixed in a certain proportion and then enter the inner ring of the primary thickening tank 4 tangentially, generating centrifugal force through rotation. The inner ring extends below the slurry surface, utilizing centrifugal force to thoroughly mix the slurry and acidic water for preliminary classification. The sediment can then settle directly along the central axis, reducing the impact of the sediment in the inner ring on the external acidic mine wastewater and slurry mixture, thus improving sedimentation efficiency. The overflow portion enters the outer ring for secondary centrifugal classification. Through these two centrifugal classifications in both the inner and outer rings, suspended solids in the slurry and acidic water, as well as the precipitates formed by their reaction, are concentrated and settled. The overflow liquid, after classification by centrifugal force in both the inner and outer rings, reaches a relatively stable state and enters the thickening tank for further sedimentation, improving sedimentation efficiency. The inner ring of the cyclone device in the secondary thickening tank 5 is equipped with an overflow inlet from the primary thickening tank, and the other components are the same as in the primary thickening tank 4.

[0036] The outlet of tailings dam 7 is connected to overflow well 8, and the outlet of overflow well 8 is connected to sewage treatment plant 9.

[0037] The specific steps for treating acidic mine water using the above system are as follows:

[0038] S1. Wastewater from various mining sites, including production process wastewater, rainwater leaching water, and mine fissure water, is mixed with tailings slurry from the pyrite beneficiation workshop in the ore dressing line by the inlet pump 2 and the tailings slurry pump 3. The mixture then enters the primary thickening tank 4 (D=50m, effective water depth 2.5m, hydraulic retention time 4.2h) for centrifugal separation and sedimentation.

[0039] S2. The sludge settled in the primary thickening tank 4 enters the tailings pond 7, and the supernatant after sedimentation enters the secondary thickening tank 5 (D=50m, effective water depth 2.5m, hydraulic retention time 4.2h) for secondary centrifugal separation and sedimentation.

[0040] S3. After the secondary centrifugal separation and sedimentation is completed, the supernatant enters the return water tank for reuse in the mineral processing, and the sludge enters the tailings dam 7.

[0041] The effluent from the two-stage thickening and centrifugal sedimentation process must meet the requirements for mineral processing water, specifically as follows:

[0042] Table 1 Water Quality Requirements for Reclaimed Water Treatment

[0043]

[0044]

[0045] S4. The supernatant in tailings dam 7 overflows through overflow well 8 to wastewater treatment plant 9 for treatment. The pH of the overflow water is greater than 6. Figure 2 As shown, after pH adjustment, oxidation, neutralization coagulation, flocculation, sedimentation, and pH adjustment treatment, the effluent is discharged into outlet 10.

[0046] The reaction involved in this embodiment is as follows:

[0047] 2H + +2Na₂SiO₃→H₂O+SiO₂↓+2Na 2+ ;

[0048] Fe2O3+6H + →2Fe 3+ +3H2O;

[0049] Fe3O4+8H + →2Fe 3+ +Fe 2+ +4H2O;

[0050] Al₂O₃ + 6H₂O + →2Al 3+ +3H2O;

[0051] Zn 2+ +2Na₂SiO₃→ZnSiO₃↓+2Na 2+ ;

[0052] Fe 2+ +2Na₂SiO₃→FeSiO₃↓+2Na 2+ ;

[0053] Mn 2+ +2Na₂SiO₃→MnSiO₃↓+2Na 2+ .

[0054] Using the traditional lime neutralization method for wastewater treatment as a comparative example, the main neutralizing agents used in this process are lime and flocculant PAM. Aeration oxidation is carried out simultaneously with neutralization, and after adding flocculant, flocculation and precipitation occur, thereby removing metal ions.

[0055] The reactions involved in this comparative example are as follows:

[0056] Ca(OH)2+H2SO2→CaSO4·2H2O↓+H2O;

[0057] MeSO4+Ca(OH)2→CaSO4·2H2O↓+Me(OH)2;

[0058] 2Fe 2+ +1 / 2O2+2H + →2Fe 3+ +H2O;

[0059] Mn 2+ +1 / 2O₂ + H₂O → MnO₂↓ + OH⁻ - .

[0060] The water treated using the above embodiments and comparative examples can achieve the same treatment effect. However, this embodiment does not use the neutralizing agent lime and the flocculant PAM, which reduces costs compared to traditional methods and does not produce neutralization slag. 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.

[0061] Therefore, the present invention provides an industrial waste recycling system and treatment method for acidic mine water. It uses high-density mud as tailings slurry from mineral processing waste. By utilizing the concept of "treating waste with waste", it not only reduces the cost of tailings and acidic mine wastewater treatment, but also saves the amount of water replenishment and acid reagent addition in the recycling process (mineral processing). In addition, various iron, manganese and zinc pollutants are purified in this process, reducing the discharge of pollutants in the entire process.

[0062] 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 processing method of industrial waste for acid mine drainage treatment system, which is realized by a processing system comprising a tailing slurry, an acid water adjusting pool, a first thickening pool, a second thickening pool and a tailing pool, wherein the tailing slurry is connected with the first thickening pool through a tailing slurry pump, the acid water adjusting pool is connected with the first thickening pool through a water inlet pump, the liquid outlet of the first thickening pool is connected with the second thickening pool, the mud outlets of the first thickening pool and the second thickening pool are connected with the tailing pool, and the first thickening pool and the second thickening pool both have a double cyclone concentration dewatering structure, characterized in that, The method comprises the following steps: S1, the mine wastewater in the acid water adjusting pool is mixed with the tailing slurry in the beneficiation line and then enters a first thickener for centrifugal separation and precipitation; the pH value of the tail water in the acid water adjusting pool is 2-3; the tailing slurry is the waste tailing slurry from the pyrite beneficiation workshop, and the main components of the tailing slurry are silicate, Al2O3, Fe2O3 and Fe3O4; the water content of the tailing sand in the tailing slurry is 10-20%, and the tailing sand comprises 3-10% of S, 5-10% of Fe, 40-60% of SiO2, 0-5% of Al2O3 and 2-5% of organic carbon; S2, the sludge after the precipitation enters a tailing pool, and the supernatant after the precipitation enters a second thickener for secondary centrifugal separation and precipitation; S3, after the secondary centrifugal separation and precipitation, the supernatant enters a reuse water pool for reuse in the beneficiation process, and the sludge enters the tailing pool; S4, the supernatant in the tailing pool is overflowed to a sewage treatment station through an overflow well, and the tail water after the treatment is discharged into a discharge port.

2. The treatment method of claim 1, wherein: The outlet of the second thickener is connected with the reuse water pool.

3. The treatment method of claim 1, wherein: The outlet of the tailing pool is connected with the overflow well, and the outlet of the overflow well is connected with the sewage treatment station.

4. The treatment method of claim 1, wherein: In S1, the hydraulic retention time of the first thickener is 4-6 h, and the rotational flow speed is 0-3500 r / min.

5. The treatment method of claim 1, wherein: In S2, the hydraulic retention time of the second thickener is 4-6 h, and the rotational flow speed is 0-3500 r / min.

6. The treatment method of claim 1, wherein: In S4, the pH of the overflow water overflowed to the sewage treatment station is greater than 6.

7. The treatment method of claim 1, wherein: In S4, the sewage treatment station comprises a pH adjusting pool, an oxidation pool, a coagulation pool, a flocculation pool, a sedimentation pool, a pH readjusting pool and a discharge port.

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