Treatment system and treatment method for recycling industrial wastes in acid mine water

Abstract

The invention discloses a treatment system and a treatment method for recycling industrial waste in acid mine water, and belongs to the technical field of acid mine water treatment.The system comprises tailing slurry, an acid water adjusting reservoir, a first-stage thickening pond, a second-stage thickening pond and a tailing pond, the tailing slurry is connected with the first-stage thickening pond through a tailing slurry pump, and the acid water adjusting reservoir is connected with the second-stage thickening pond; the acid water adjusting reservoir is connected with the first-stage thickening tank through a water inlet pump, a liquid outlet of the first-stage thickening tank is connected with the second-stage thickening tank, sludge outlets of the first-stage thickening tank and the second-stage thickening tank are both connected with the tailing pond, and the system is used for treating the acid mine water. According to the method, the concept of treating waste with waste is used for treating the acid mine water, so that the treatment cost of the tailings and the acid mine wastewater is reduced, the supplement amount of purified water and the addition amount of an acid medicament in a recycling process (mineral processing process) are saved, and various iron, manganese and zinc pollutants are purified in the process; and the discharge of pollutants in the whole process is reduced.

Description

Technical Field

[0001] The present invention relates to the field of acid mine water treatment, and in particular to an acid mine water treatment system and a treatment method for recycling industrial waste. Background Art

[0002] Acid mine water is one of the main pollutants produced during mining. Rich in heavy metal ions such as sulfuric acid, iron and manganese, and suspended solids, if discharged directly without treatment, it will lead to water acidification, soil degradation, and ecosystem damage, seriously threatening the surrounding environmental safety and human health. Currently, traditional methods for treating acid mine water include lime neutralization and precipitation, redox methods, iron chip replacement methods, electrolysis, adsorption, wetland methods, lime ditch methods, permeable reaction wall methods, and biosulfurization methods. However, these methods have significant drawbacks:

[0003] Adsorption, iron chip replacement, and biosulfurization can only remove heavy metals from wastewater; wetland methods can remove heavy metals and some sulfates simultaneously, but the residence time is long and the area occupied is large; adsorption, redox, lime ditch, and permeable reaction walls require frequent material replacement and a long residence time; chemical neutralization precipitation requires the continuous addition of alkaline agents to adjust the pH value, which is costly and easily produces a large amount of neutralized slag with a high water content and difficult to handle; the electrolysis method consumes too much electricity. In addition, most of the treated wastewater is directly discharged, and water resource recycling is not achieved, which is contrary to the mining industry's demand for water conservation and consumption reduction; and the tailings slurry (rich in fine-grained minerals, residual agents, and heavy metals) and acidic mine water generated during the mineral processing process are mostly treated separately, and no waste linkage disposal mechanism has been formed, resulting in a continuous increase in the stockpile of tailings ponds, posing a risk of dam collapse and heavy metal migration pollution.

[0004] Based on the above problems, how to achieve the coordinated 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 urgently needs to be broken through in the green development of mines. Summary of the Invention

[0005] The purpose of the present invention is to provide an acid mine water treatment system and a treatment method for recycling industrial waste to solve the problems in the background technology.

[0006] To achieve the above-mentioned objectives, the present invention provides an industrial waste reuse acid mine water treatment system, comprising tailings slurry, an acid water regulating reservoir, a primary thickener, a secondary thickener and a tailings reservoir, wherein the tailings slurry is connected to the primary thickener via a tailings slurry pump, the acid water regulating reservoir is connected to the primary thickener via an inlet pump, the liquid outlet of the primary thickener is connected to the secondary thickener, and the mud outlets of the primary thickener and the secondary thickener are both connected to the tailings reservoir.

[0007] Preferably, the water outlet of the secondary thickening tank is connected to the reuse water tank; and both the primary thickening tank and the secondary thickening tank have a double cyclone concentration and dehydration structure.

[0008] Preferably, the liquid outlet of the tailings pond is connected to an overflow well, and the water outlet of the overflow well is connected to a sewage treatment station.

[0009] Based on the above treatment system, the present invention proposes a method for recycling industrial waste for acid mine water treatment, comprising the following steps:

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

[0011] S2. The sludge after sedimentation in the primary thickener enters the tailings pond, and the supernatant after sedimentation enters the secondary thickener for secondary centrifugal separation and sedimentation;

[0012] S3. After the secondary centrifugal separation and sedimentation is completed, the supernatant enters the return water tank and is reused in the mineral processing process, and the sludge enters the tailings pond;

[0013] S4. The supernatant in the tailings pond overflows through the overflow well to the sewage treatment station for treatment, and after treatment, the tail water is discharged into the discharge port.

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

[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 S1, the pH of the tail water in the acid water regulating reservoir is 2-3.

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

[0018] Preferably, in S2, the hydraulic retention time of the secondary thickening tank is 4 to 6 hours, and the cyclone speed is 0 to 3500 r / min.

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

[0020] Preferably, in said S4, the sewage treatment station includes a pH adjustment tank, an oxidation tank, a coagulation tank, a flocculation tank, a sedimentation tank, a pH callback tank and a discharge port.

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

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

[0023] (1) The method protected by the present invention uses the existing solid waste beneficiation tailings slurry as a neutralizing agent and heavy metal removal agent without using a neutralizing agent and a flocculant, and utilizes the main components of the tailings slurry, silicate, Al2O3, Fe2O3 and Fe3O4, to form a water-rock and neutralization reaction, and to form ion exchange, hydrolysis reaction, co-precipitation, sweeping capture, adsorption and neutralization with other metal ions and colloids; the treated acid mine wastewater is directly reused for sulfur concentrate beneficiation treatment, 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 acid mine wastewater, which also has a great impact on reducing the concentration of heavy metals in the mineral processing production process; at the same time, the wastewater is recycled and the cost of treating the tailings slurry and acid mine wastewater is reduced.

[0024] (2) The tailings slurry used in the present invention has a high content of silicate, iron oxide and aluminum oxide. After the tailings slurry is mixed with acid water, it is directly mixed with H + and Fe 2+ 、Mn 2+ and Zn 2+ Dilution, neutralization, and metal precipitation occur. Crystals formed by metal silicate precipitation act as colloid nuclei with the remaining granular tailings, forming a combined action of co-precipitation, sweeping, capture, and adsorption with metal ions and other colloids. This significantly improves the morphology of the sediment and the amount of sediment, significantly increases the sedimentation rate, and accelerates settling, achieving the triple effects of neutralization, removal of metal ions, and suspended solids.

[0025] (3) The traditional method requires the use of treatment processes such as neutralization oxidation, flocculation, sedimentation tank and reuse water tank. In the present invention, after the tailings slurry is mixed with the acid mine wastewater, the mud and water are initially separated by a primary thickening tank, and the mud residue is directly stored in the tailings pond, avoiding the energy consumption and equipment investment of the traditional tailings slurry concentration alone, while reducing the amount of sludge generated by the acid mine wastewater treatment; the primary thickening tank quickly removes suspended matter and some heavy metal ions (such as Fe 2+ 、Mn 2+); The secondary thickening tank further reduces the turbidity of the supernatant through static sedimentation and the synergistic effect of residual reagents, and stabilizes the pH value at 6.0-7.5, which fully meets 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, replacing fresh water, thereby improving the recycling rate of water resources in the mining area.

[0026] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0029] Reference numerals:

[0030] 1. Acid water regulating reservoir; 2. Water inlet pump; 3. Tailings slurry pump; 4. Primary thickening tank; 5. Secondary thickening tank; 6. Recycled water tank; 7. Tailings pond; 8. Overflow well; 9. Sewage treatment station; 10. Discharge outlet. DETAILED DESCRIPTION

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

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0033] Example

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

[0035] The liquid outlet of the primary thickener 4 is connected to the secondary thickener 5. The supernatant from the primary thickener 5 continues to react in the secondary thickener. The mud outlets of both the primary and secondary thickeners 4 and 5 are connected to the tailings pond 7. The water outlet of the secondary thickener 5 is connected to the reuse water tank 6 for recycling. Both primary and secondary thickeners 4 and 5 feature a high-efficiency, dual-cyclone thickener. This configuration, based on existing technology, comprises a central axis and an inner and outer rings arranged sequentially around the central axis. The central axis is connected to the inner ring, which in turn is connected to the outer ring. The inner ring is an inverted conical steel ring with a 15° inverted cone angle and is equipped with inlets for acid mine drainage and slurry. The mixture of acid mine drainage and slurry is initially concentrated and settled through centrifugal classification in the inner and outer rings. The overflow slurry, after classification by the centrifugal action of the inner and outer rings, reaches a relatively stable dispersion and enters the thickener for further concentration and settlement. The central axis of the cyclone is connected to both the inner and outer rings and leads to the thickening tank hopper. Mine wastewater and tailings slurry are mixed in a certain proportion and then flow tangentially into the primary thickening tank 4. The inner ring rotates to generate a centrifugal effect. The inner ring extends below the slurry surface. Centrifugal force thoroughly mixes the slurry and acid water, and after initial classification, the sand settles directly along the central axis, reducing the impact of the inner ring sand on the external acidic mine wastewater and slurry mixture and improving sedimentation efficiency. The overflow is relatively stably dispersed and enters the outer ring for secondary centrifugal classification. After these two centrifugal classifications, the slurry, acid water, and the resulting precipitate are concentrated and settled. After being centrifugally classified by the inner and outer rings, the overflow reaches a relatively stable dispersion and enters the thickening tank for further sedimentation, improving sedimentation efficiency. The inner ring of the cyclone in the secondary thickening tank 5 is equipped with an inlet for the overflow from the primary thickening tank, as are other thickening tanks 4 of the same level.

[0036] The liquid outlet of the tailings pond 7 is connected to the overflow well 8, and the water outlet of the overflow well 8 is connected to the sewage treatment station 9.

[0037] The above system is used to treat acid mine water. The specific steps are as follows:

[0038] S1, the acid water regulating reservoir 1, the process wastewater from each mining site, rainwater leaching water, mine fissure water and other process wastewater is mixed with the waste tailings slurry from the pyrite beneficiation workshop in the beneficiation line extracted by the tailings slurry pump 3 through the water inlet pump 2, and enters the primary thickener 4 (D = 50m, effective water depth 2.5m, hydraulic retention time 4.2h) for centrifugal separation and sedimentation;

[0039] S2. The sludge after sedimentation in the primary thickener 4 enters the tailings pond 7, and the supernatant after sedimentation enters the secondary thickener 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 and is reused in the mineral processing process, and the sludge enters the tailings pond 7;

[0041] The effluent standards after centrifugal separation and sedimentation in the two-stage thickening tank must meet the water requirements for mineral processing. The specific water quality requirements are as follows:

[0042] Table 1 Water quality requirements for recycled water treatment

[0043]

[0044]

[0045] S4, the supernatant in the tailings pond 7 overflows through the overflow well 8 to the sewage treatment station 9 for treatment. The pH of the overflow water is greater than 6. Figure 2 As shown, after the pH adjustment, oxidation, neutralization coagulation, flocculation, precipitation, and pH adjustment treatment are completed, the tail water is discharged into the discharge port 10.

[0046] The reactions involved in this embodiment are 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+6H + →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] The traditional lime neutralization method was used for wastewater treatment as a comparative example. The main neutralizing agents used in this process were lime and flocculant PAM. Aeration oxidation was performed during neutralization, and flocculants were added for flocculation and precipitation to remove 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+ +H2 O;

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

[0060] The water quality after treatment by the above embodiment and the comparative example can achieve the same treatment effect, but the neutralizing agent lime and the flocculating agent PAM are not used in this embodiment, which reduces the cost compared with the traditional method and does not produce neutralization slag; secondly, the traditional method in the comparative example directly discharges the water after treatment, while in this embodiment, the treated water is used for other mineral processing processes, saving a large amount of clean water.

[0061] Therefore, the present invention provides an industrial waste recycling acid mine water treatment system and treatment method, which adopts high-density mud as the tailings slurry of the mineral processing process waste, and utilizes the concept of "treating waste with waste", which not only reduces the cost of tailings and acid mine wastewater treatment, but also saves the amount of clean water replenishment and acidic agent addition in the recycling process (mineral processing process), and in this process, various iron, manganese and zinc pollutants are purified, 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 rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An industrial waste recycling system for acid mine water treatment, characterized by: It includes tailings slurry, acid water regulating reservoir, primary thickening tank, secondary thickening tank and tailings pond. The tailings slurry is connected to the primary thickening tank through a tailings slurry pump, the acid water regulating reservoir is connected to the primary thickening tank through an inlet pump, the liquid outlet of the primary thickening tank is connected to the secondary thickening tank, and the mud outlets of the primary thickening tank and the secondary thickening tank are both connected to the tailings pond.

2. The acid mine water treatment system for recycling industrial waste according to claim 1, characterized in that: The water outlet of the secondary thickening tank is connected to the reuse water tank.

3. The acid mine water treatment system for recycling industrial waste according to claim 1, characterized in that: The liquid outlet of the tailings pond is connected to the overflow well, and the water outlet of the overflow well is connected to the sewage treatment station.

4. A method for recycling industrial waste into an acid mine water treatment system based on any one of claims 1 to 3, characterized in that: The following steps are involved: S1. The mine wastewater in the acid water regulating reservoir is mixed with the tailings slurry in the beneficiation line and then enters the primary thickening tank for centrifugal separation and sedimentation; S2, the precipitated sludge enters the tailings pond, and the supernatant enters the secondary thickening tank for secondary centrifugal separation and sedimentation; S3. After the secondary centrifugal separation and sedimentation is completed, the supernatant enters the reuse water pool and is reused in the mineral processing process, and the sludge enters the tailings pond; S4. The supernatant in the tailings pond overflows through the overflow well to the sewage treatment station for treatment, and after treatment, the tail water is discharged into the discharge port.

5. The processing method according to claim 4, characterized in that: In S1, the tailings slurry comes from the waste tailings slurry of the pyrite beneficiation workshop.

6. The processing method according to claim 4, characterized in that: The water content of the 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.

7. The processing method according to claim 4, characterized in that: In the S1, the hydraulic retention time of the primary thickener is 4 to 6 hours, and the cyclone speed is 0 to 3500 r / min.

8. The processing method according to claim 4, characterized in that: In the S2, the hydraulic retention time of the secondary thickening tank is 4 to 6 hours, and the cyclone speed is 0 to 3500 r / min.

9. The processing method according to claim 4, characterized in that: In the above-mentioned S4, the pH of the overflow water flowing into the sewage treatment plant is greater than 6.

10. The processing method according to claim 4, characterized in that: In the above-mentioned S4, the sewage treatment station includes a pH adjustment tank, an oxidation tank, a coagulation tank, a flocculation tank, a sedimentation tank, a pH readjustment tank and a discharge port.

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