Non-ferrous metal mine acid wastewater treatment system

Abstract

The utility model relates to a nonferrous metal mine acid wastewater treatment system which comprises an adjusting tank, a water outlet of the adjusting tank is sequentially connected to a first-stage reaction tank, a second-stage reaction tank and a third-stage reaction tank, and the first-stage reaction tank, the second-stage reaction tank and the third-stage reaction tank are communicated through water inlet through holes and water outlet through holes formed in the side walls. A water outlet through hole of the third-stage reaction tank is connected to a water inlet of the thickening tank, an overflow port of the thickening tank is connected to the water return tank through a self-flowing pipe, an underflow port of the thickening tank is communicated with the first-stage reaction tank through a slurry pump and is further communicated with a tailing pump room through a self-flowing channel, and the water return tank is communicated with the high-level water tank through a water return pump. According to the system, a high-density slurry method is adopted, bottom mud settled in the thickening tank is subjected to reflux circulating treatment, lime consumption can be reduced, the sludge settling and separating speed can be increased, and the bottom mud is easily close to and attached to calcium sulfate with negative potential to form crystal nucleuses and continuously expand, so that the surface load of the thickening tank is increased, and the effluent quality is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of mine sewage treatment, in particular to a non-ferrous metal mine acid wastewater treatment system. Background Art

[0002] The formation of acidic wastewater in non-ferrous metal mines is mainly due to the oxidation of metallic iron sulfide ore to form sulfuric acid and iron sulfate, which further oxidizes other metals in the ore to form acidic wastewater containing multiple metal ions. Direct discharge will cause damage to the water bodies, vegetation, aquatic organisms and related food chain organisms around the mining area, and therefore requires targeted treatment.

[0003] The treatment methods for heavy metal wastewater generally include chemical precipitation, ion exchange resin, adsorption, electrolysis, activated carbon adsorption, reverse osmosis, electrodialysis, evaporation concentration and biological methods. Among them, chemical precipitation is the most widely used method for treating acid mine wastewater. Figure 1 As shown, acidic wastewater undergoes flocculation and sedimentation in a two-stage thickening tank with the addition of lime milk and flocculants, converting heavy metals into precipitates for removal. However, this traditional chemical precipitation system is relatively crude in wastewater treatment, resulting in low heavy metal removal rates and high effluent quality standards. As effluent quality standards become increasingly stringent, traditional chemical precipitation methods are increasingly unable to meet these requirements. Therefore, a new process system for treating acidic wastewater from non-ferrous metal mines is needed. Utility Model Content

[0004] The utility model provides a non-ferrous metal mine acid wastewater treatment system.

[0005] The specific technical solution of the utility model is:

[0006] A non-ferrous metal mine acid wastewater treatment system includes a regulating tank, the water outlet of the regulating tank is connected to a primary reaction tank, a secondary reaction tank and a tertiary reaction tank in sequence, the primary reaction tank, the secondary reaction tank and the tertiary reaction tank are connected through water inlet and outlet through holes opened on the side walls, the water outlet through hole of the tertiary reaction tank is connected to the water inlet of the thickening tank, the overflow port of the thickening tank is connected to the return water tank through a gravity pipe, the underflow port of the thickening tank is connected to the primary reaction tank through a slurry pump, the underflow port of the thickening tank is also connected to the tailings pump room through a gravity channel, and the return water tank is connected to the high-level water tank through a return water pump.

[0007] Furthermore, preferably, the feed port of the primary reaction tank is connected to the lime milk preparation system, the feed port of the tertiary reaction tank is connected to the PAM preparation system, and the feed ports of the primary reaction tank, the secondary reaction tank and the tertiary reaction tank are all connected to the blast system.

[0008] Furthermore, preferably, the primary reaction tank, the secondary reaction tank and the tertiary reaction tank are all equipped with a stirrer.

[0009] The beneficial effects of the present invention are as follows: the system adopts a high-density slurry method to recirculate the sediment from the thickening tank for treatment. The effective calcium contained in the sediment can reduce the consumption of lime. The sediment recirculation also causes the sediment to crystallize and coarsen, which can accelerate the sedimentation and separation of sludge. The sediment is very easy to approach and adhere to the calcium sulfate with a negative potential, forming crystal nuclei that continue to expand, thereby increasing the surface load of the thickening tank and improving the effluent water quality. The calcium ion concentration in the treated effluent is significantly reduced, effectively delaying the scaling of equipment and pipelines. In addition, the concentrated high-concentration sediment is discharged by gravity to the slurry pool of the tailings pump room. Since it contains some effective calcium, it can increase the pH value of the tailings water and reduce the concentration of heavy metals in the tailings water, which has a certain improvement effect on the water quality. At the same time, it can increase the permeability coefficient of the tailings and have a positive impact on the permeability of the tailings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is an equipment association diagram of the existing non-ferrous metal mine acid wastewater treatment system;

[0011] Figure 2 This is an equipment association diagram of a non-ferrous metal mine acid wastewater treatment system of the utility model;

[0012] In the figure: 1- regulating tank, 2- primary reaction tank, 3- secondary reaction tank, 4- tertiary reaction tank, 5- thickening tank, 6- return water tank, 7- slurry pump, 8- tailings pump room, 9- return water pump, 10- high level water tank, 11- lime milk preparation system, 12- PAM preparation system, 13- air blast system, 14- 2# thickening tank. DETAILED DESCRIPTION

[0013] In order to make the technical problems and technical solutions solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0014] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0015] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on the specific circumstances.

[0016] like Figure 2 As shown, a non-ferrous metal mine acid wastewater treatment system includes a regulating tank 1, the outlet of the regulating tank 1 is connected to the primary reaction tank 2, the secondary reaction tank 3 and the tertiary reaction tank 4 in sequence, the primary reaction tank 2, the secondary reaction tank 3 and the tertiary reaction tank 4 are connected through water inlet and outlet holes opened on the side walls (this connection method can avoid the problem of pipe scaling caused by traditional pipe connection), the outlet hole of the tertiary reaction tank 4 is connected to the water inlet of the thickening tank 5, the overflow port of the thickening tank 5 is connected to the return water tank 6 through a gravity pipe, the underflow port of the thickening tank 5 is also connected to the primary reaction tank 2 through a slurry pump 7, the underflow port of the thickening tank 5 is also connected to the tailings pump room 8 through a gravity channel, and the return water tank 6 is connected to the high-level water tank 10 through a return water pump 9.

[0017] All of the above equipment uses existing equipment. For example, the shell of the thickening tank 5 is a reinforced concrete elevated elastic structure, adopts a deep cone and large slope reinforced concrete self-waterproof structure, and has a diameter of 24m; the return water pump uses an IS125-100-315 single-stage single-suction centrifugal pump.

[0018] Working Principle: During sewage treatment, acidic wastewater is first transferred to equalization tank 1 for homogenization. The wastewater is then transferred to primary reactor 2, where it is thoroughly mixed with lime milk for neutralization, adjusting the pH of the wastewater to 9.0. Simultaneously, air is introduced into primary reactor 2, causing heavy metal ions such as Cu, Pb, Zn, and Cd in the wastewater to react with the lime to form heavy metal hydroxide precipitates. The effluent then flows directly into secondary reactor 3 through the outlet holes in the sidewall of primary reactor 2. Further aeration continues in the secondary reactor, oxidizing Fe2+ in the wastewater to Fe3+. The oxidized wastewater then flows directly into tertiary reactor 4 through the outlet holes in secondary reactor 3. To increase sedimentation rate, a high-molecular-weight polyacrylamide flocculant (PAM) is added to tertiary reactor 4. After flocculation by the PAM, the wastewater flows by gravity into thickening tank 5 for concentrated sedimentation. The supernatant from the thickening tank 5 overflows from the overflow port into the recirculation tank 6. The sludge in the thickening tank 5 is returned to the primary reaction tank 2 for recycling via a slurry pump 7. As the sludge concentration increases during recycling, it no longer circulates and instead flows through a gravity channel to the tailings pump house 8 for storage. The supernatant from the recirculation tank 6 is then pumped to the high-level water tank 10 for recycling via a recirculation pump 9.

[0019] This system utilizes a high-density slurry method, recycling sediment from the thickening tank for treatment. Because the returned sludge contains some available calcium, lime consumption can be reduced by approximately 5% to 10% compared to existing systems. The return sludge also crystallizes and coarsens particles, accelerating sludge settling and separation. The settled sludge readily attracts and attaches to negatively charged calcium sulfate, forming crystal nuclei that expand and expand. This increases the surface load of the thickening tank and improves effluent quality. The treated effluent significantly reduces calcium ion concentration, effectively slowing scaling of equipment and pipelines, requiring equipment cleaning only once or twice per year. Furthermore, the concentrated, high-density sludge, which gravity-discharges to the slurry pond at the tailings pumphouse, contains some available calcium, which raises the pH of the tailings water and reduces heavy metal concentrations, significantly improving water quality. It also increases the permeability coefficient of the tailings, positively impacting its permeability.

[0020] Preferably, in order to facilitate the addition of reaction reagents and reaction gases, the feed port of the primary reaction tank 2 is connected to the lime milk preparation system 11, the feed port of the tertiary reaction tank 4 is connected to the PAM preparation system 12, and the feed ports of the primary reaction tank 2, the secondary reaction tank 3, and the tertiary reaction tank 4 are all connected to the air blowing system 13. The lime milk preparation system 11 includes a lime silo and a lime milk stirring tank, which are used to prepare lime milk from refined lime powder and add the lime milk to the primary reaction tank 2 for neutralization and precipitation reaction with wastewater. The lime milk preparation system 11 can cooperate with a pH online detector to control the amount of lime milk added; the PAM preparation system 12 includes a dissolving tank and a dosing pump, which are used to prepare PAM reagents and add the PAM reagents to the tertiary reaction tank 4 for flocculation reaction; the air blowing system 13 uses a G10-1.5 Roots blower to blow air and aerate the three reaction tanks to accelerate the oxidation reaction.

[0021] In this way, when the three reaction tanks react, the addition of reaction reagents and reaction gases can be completed through the lime milk preparation system 11, the PAM preparation system 12 and the blast system 13, making the system more convenient to use.

[0022] Preferably, the primary reaction tank 2, the secondary reaction tank 3, and the tertiary reaction tank 4 are all equipped with a mixer, and the mixer can be an XFJ-3000 mixing reaction mixer. By configuring the mixers in the three reaction tanks, the wastewater can be fully mixed with the reaction reagents and reaction gases, thereby improving the reaction efficiency and reaction effect, reducing the concentration of heavy metals in the wastewater, and improving the effluent water quality.

[0023] It should be noted that this application only involves the application of the above-mentioned existing equipment and does not involve the structural modification of the equipment.

[0024] The present invention is described in detail above through specific and preferred embodiments, but those skilled in the art should understand that the present invention is not limited to the embodiments described above. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A non-ferrous metal mine acid wastewater treatment system, characterized by: The invention comprises a regulating tank (1), wherein the outlet of the regulating tank (1) is connected to a primary reaction tank (2), a secondary reaction tank (3) and a tertiary reaction tank (4) in sequence, the primary reaction tank (2), the secondary reaction tank (3) and the tertiary reaction tank (4) are connected via water inlet and outlet holes provided on the side walls, the outlet hole of the tertiary reaction tank (4) is connected to the water inlet of a thickening tank (5), the overflow port of the thickening tank (5) is connected to a return water tank (6) via a gravity pipe, the bottom flow port of the thickening tank (5) is also connected to the primary reaction tank (2) via a slurry pump (7), the bottom flow port of the thickening tank (5) is also connected to a tailings pump room (8) via a gravity channel, and the return water tank (6) is connected to a high-level water tank (10) via a return water pump (9).

2. The non-ferrous metal mine acid wastewater treatment system according to claim 1, characterized in that: The feed inlet of the primary reaction tank (2) is connected to the lime milk preparation system (11), the feed inlet of the tertiary reaction tank (4) is connected to the PAM preparation system (12), and the feed inlets of the primary reaction tank (2), the secondary reaction tank (3), and the tertiary reaction tank (4) are all connected to the blast system (13).

3. The non-ferrous metal mine acidic wastewater treatment system according to claim 1, characterized in that: The first-stage reaction tank (2), the second-stage reaction tank (3) and the third-stage reaction tank (4) are all equipped with a stirrer.

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