Method for treating mine wastewater in a roadway using a multistage heavy metal barrier

Abstract

The method for treating mine wastewater in a roadway by using a multi-stage heavy metal control barrier comprises the following steps: intercepting the outflow of a main stream of mine wastewater in a flat adit mining roadway, so as to raise the liquid level of the mine wastewater and keep the exposed ore-bearing rock stratum and surrounding rock surface below the liquid level of the mine wastewater in an anaerobic state; filling composite organic material filling bodies and composite acid buffer material filling bodies in the roadway in sequence and at intervals, so as to react with the mine wastewater respectively; and sealing the filled roadway, so that the composite organic material filling bodies and the composite acid buffer material filling bodies are completely immersed in the mine wastewater and fully react with the mine wastewater. The method directly controls the mine wastewater generated by the exposed ore-bearing rock stratum and surrounding rock in the flat adit mining roadway, fully utilizes the underground space of a mine, constructs a reaction system in the roadway, realizes in-situ inhibition of the release of heavy metal pollutants, and blocks the migration of heavy metals. The process flow is simple and the operation cost is low.

Description

TECHNICAL FIELD

[0001] The embodiment of the present disclosure belongs to the technical field of mine wastewater treatment, and particularly relates to a method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier. BACKGROUND

[0002] Traditional mine acid wastewater treatment methods generally use three categories: physical and chemical treatment methods, biochemical treatment methods, and wetland ecology treatment methods. These treatment methods are limited to "end-of-pipe" treatment of mine wastewater after it spills onto the ground surface.

[0003] The acid mine wastewater generated by mining activities has a low pH, which can further dissolve the surrounding rock and cause other associated heavy metals to leach and release into the environment, thereby having a serious adverse impact on the surrounding aquatic ecosystems, vegetation, agricultural soil, and food crops. Existing treatment methods for mine wastewater in roadways mostly use an "end-of-pipe" approach, which requires the construction of related treatment facilities at the end of the mine wastewater discharge. This treatment method has the characteristics of complex process flow, high operating cost, and high management difficulty. In addition, the treatment of mine wastewater in roadways has high requirements before treatment, and different treatment technologies have different requirements for flow rate, pH, metal concentration, slope, and flow rate. In areas with high precipitation, well-developed surface karst fissures, and good groundwater recharge conditions, it is difficult to meet the requirements before treatment, resulting in large amounts of abandoned mine wastewater and high treatment costs.

[0004] In view of the above problems, it is necessary to provide a method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier. SUMMARY

[0005] The embodiment of the present disclosure aims to at least solve one of the technical problems existing in the prior art, and provides a method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier.

[0006] The embodiment of the present disclosure provides a method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier, which comprises:

[0007] intercepting the main outflow of mine wastewater in a flat adit mining roadway to raise the liquid level of the mine wastewater in the roadway, and keeping the exposed ore-bearing rock stratum and surrounding rock surface below the liquid level of the mine wastewater in an anaerobic state;

[0008] filling a plurality of composite organic material filling bodies and a plurality of composite acid buffer material filling bodies in the roadway in sequence and at intervals to react with the mine wastewater respectively, thereby forming a multi-stage heavy metal blocking and controlling barrier;

[0009] Blocking the filled roadway to make the composite organic material filling body and the composite acid buffer material filling body completely immerse in the mine wastewater and make the mine wastewater fully react with the mine wastewater.

[0010] Optionally, the main stream of the mine wastewater in the intercepting adit mining roadway is discharged to raise the liquid level of the mine wastewater in the roadway, comprising:

[0011] The roadway is provided with a retaining wall at the end away from the roadway opening; wherein the height of the retaining wall is lower than the height of the roadway.

[0012] Optionally, the multiple composite organic material filling bodies and the multiple composite acid buffer material filling bodies are sequentially and spacedly filled in the roadway to respectively react with the mine wastewater, comprising:

[0013] The mine wastewater flows out from the top gap of the retaining wall;

[0014] The composite organic material filling body reacts with the flowed-out mine wastewater to increase the pH value of the mine wastewater and remove the metal ions in the mine wastewater.

[0015] Optionally, the multiple composite organic material filling bodies and the multiple composite acid buffer material filling bodies are sequentially and spacedly filled in the roadway to respectively react with the mine wastewater, further comprising:

[0016] The mine wastewater flows out from the top gap of the retaining wall;

[0017] The composite acid buffer material filling body reacts with the flowed-out mine wastewater to increase the pH value of the mine wastewater, and the generated precipitate fills the gap in the composite acid buffer material filling body to make the composite acid buffer material filling body tightly cover the original exposed ore-bearing stratum and surrounding rock surface.

[0018] Optionally, the multiple composite organic material filling bodies and the multiple composite acid buffer material filling bodies are sequentially and spacedly filled in the roadway to respectively react with the mine wastewater, comprising:

[0019] One of the composite organic material filling bodies and one of the composite acid buffer material filling bodies are sequentially filled in the roadway; wherein the composite organic material filling body is in contact with the retaining wall;

[0020] The remaining multiple composite organic material filling bodies and the composite acid buffer material filling bodies are sequentially and spacedly filled in the roadway to form a heavy metal control barrier.

[0021] Optionally, the multiple composite organic material filling bodies and the multiple composite acid buffer material filling bodies are sequentially and spacedly filled in the roadway to react with the mine wastewater respectively to form a heavy metal control barrier.

[0022] The multiple composite organic material filling bodies and the multiple composite acid buffer material filling bodies are sequentially filled from the inside of the roadway to the outside of the roadway.

[0023] Optionally, the filled roadway is sealed, including:

[0024] The filled roadway is sealed by a sealing wall, wherein the height of the sealing wall is lower than the height of the roadway.

[0025] Optionally, the composite acid buffer material filling body includes a first composite acid buffer material layer and a second composite acid buffer material layer.

[0026] The second composite acid buffer material layer is arranged above the first composite acid buffer material layer, wherein

[0027] The particle size of the second composite acid buffer material layer is greater than the particle size of the first composite acid buffer material layer.

[0028] Optionally, the particle size of the first composite acid buffer material layer ranges from 30 mm to 40 mm.

[0029] The particle size of the second composite acid buffer material layer ranges from 25 mm to 35 mm.

[0030] Optionally, the composite acid buffer material filling body is made of a carbonate rock material.

[0031] The composite organic material filling body is made of modified limestone, attapulgite, iron powder, activated carbon and straw material.

[0032] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal control barrier according to the embodiments of the present disclosure can intercept the main outflow of mine wastewater in a flat adit mining roadway, improve the liquid level of the mine wastewater in the roadway, keep the exposed ore-bearing rock stratum and surrounding rock surface below the liquid level of the mine wastewater in an anaerobic state, preliminarily block the precipitation of metal ions in the exposed ore-bearing rock stratum and surrounding rock surface, and reduce the heavy metal pollutants in the acid mine wastewater.

[0033] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal control barrier according to the present disclosure can effectively remove metal ions in the mine wastewater and control the concentration of heavy metals in the mine wastewater by reacting the composite organic material filling body with the mine wastewater to improve the pH value of the mine wastewater; the precipitate generated by the reaction of the composite acid buffer material filling body with the mine wastewater can fill the gaps in the composite acid buffer material filling body, so that the composite acid buffer material filling body tightly wraps the exposed ore-bearing rock stratum and surrounding rock surface in the roadway, thereby effectively controlling the water-rock reaction process in the roadway and greatly reducing the amount of pollutants in the mine wastewater.

[0034] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal control barrier according to the present disclosure can effectively remove metal ions in the mine wastewater and control the concentration of heavy metals in the mine wastewater by reacting the composite organic material filling body with the mine wastewater to improve the pH value of the mine wastewater; the precipitate generated by the reaction of the composite acid buffer material filling body with the mine wastewater can fill the gaps in the composite acid buffer material filling body, so that the composite acid buffer material filling body tightly wraps the exposed ore-bearing rock stratum and surrounding rock surface in the roadway, thereby effectively controlling the water-rock reaction process in the roadway and greatly reducing the amount of pollutants in the mine wastewater.

[0035] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal control barrier according to the present disclosure can effectively remove metal ions in the mine wastewater and control the concentration of heavy metals in the mine wastewater by reacting the composite organic material filling body with the mine wastewater to improve the pH value of the mine wastewater; the precipitate generated by the reaction of the composite acid buffer material filling body with the mine wastewater can fill the gaps in the composite acid buffer material filling body, so that the composite acid buffer material filling body tightly wraps the exposed ore-bearing rock stratum and surrounding rock surface in the roadway, thereby effectively controlling the water-rock reaction process in the roadway and greatly reducing the amount of pollutants in the mine wastewater.

[0036] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal control barrier according to the present disclosure can effectively remove metal ions in the mine wastewater and control the concentration of heavy metals in the mine wastewater by reacting the composite organic material filling body with the mine wastewater to improve the pH value of the mine wastewater; the precipitate generated by the reaction of the composite acid buffer material filling body with the mine wastewater can fill the gaps in the composite acid buffer material filling body, so that the composite acid buffer material filling body tightly wraps the exposed ore-bearing rock stratum and surrounding rock surface in the roadway, thereby effectively controlling the water-rock reaction process in the roadway and greatly reducing the amount of pollutants in the mine wastewater. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 This is a schematic flowchart of a method for treating mine wastewater in a roadway using a multi-level heavy metal barrier, as described in one embodiment of this disclosure.

[0038] Figure 2 This is a schematic diagram of the original liquid level of mine wastewater in the roadway in the existing technology;

[0039] Figure 3 This is a schematic diagram of the mine wastewater level in the roadway after the construction of the retaining wall, as described in another embodiment of this disclosure.

[0040] Figure 4 This is a schematic diagram illustrating the filling method of a roadway using a composite organic material filler and a composite acid buffer material filler, as described in another embodiment of this disclosure.

[0041] Figure 5 This is a schematic diagram of the pH and concentration of various heavy metal ions in mine wastewater after treatment in a tunnel using a multi-level heavy metal barrier, as described in another embodiment of this disclosure. Detailed Implementation

[0042] To enable those skilled in the art to better understand the technical solutions of the embodiments of this disclosure, the embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0043] like Figure 1 As shown, this disclosure provides a method S100 for treating mine wastewater in roadways using a multi-level heavy metal barrier, the method S100 including:

[0044] S110. Intercept the main outflow of mine wastewater in the adit mining roadway to raise the liquid level of the mine wastewater in the roadway, so as to keep the exposed ore-bearing rock strata and surrounding rock surface below the liquid level of the mine wastewater in an anaerobic state.

[0045] like Figure 2 As shown, the initial liquid level of mine wastewater in the adit is mostly located near the roadway surface. Acidic substances such as iron and manganese in the mountain above the roadway surface are continuously dissolved by the wastewater and flow out of the mine shaft. While the wastewater is flowing out of the mine shaft, air is constantly flowing into the roadway to ensure the dissolved oxygen concentration in the mine wastewater. The dissolved oxygen in the water reacts with low-valence metal ions such as iron and manganese to generate high-valence metal ions, which further reduces the pH value of the wastewater and intensifies the dissolution of metal ions in the ore deposit.

[0046] Based on this, in this embodiment, as Figure 3As shown, a retaining wall 110 is installed at the farthest end of the roadway away from the roadway entrance. The height of the retaining wall 110 is lower than the height of the adit mining roadway 200, that is, there is a gap between the top of the retaining wall 110 and the top of the adit mining roadway 200, and the mine wastewater in the adit mining roadway 200 can flow out through the gap at the top of the retaining wall 110.

[0047] It should be noted that the retaining wall 110 can be made of reinforced concrete, or other types of walls. This embodiment does not impose specific limitations and can be selected according to actual needs.

[0048] By setting up retaining walls, the main outflow of mine wastewater in adits can be intercepted, raising the wastewater level within the tunnels. This allows acidic substances such as iron and manganese below the wastewater level to integrate with the exposed ore-bearing rock strata and surrounding rock surfaces, preventing further erosion by the wastewater. Rainwater and other replenishment water only dissolve acidic substances such as iron and manganese above the highest level, initially blocking and reducing pollutants in the acidic mine wastewater. Furthermore, the raised wastewater level in the tunnels also keeps the exposed ore-bearing rock strata and surrounding rock surfaces below the wastewater level in an anaerobic state, reducing the precipitation of metal ions from these surfaces and further blocking and reducing heavy metal pollutants in the acidic mine wastewater.

[0049] S120. Multiple composite organic material fillers and multiple composite acid buffer material fillers are sequentially and intermittently filled into the roadway to react with the mine wastewater respectively.

[0050] After raising the wastewater level in the adit mining roadway 200 by constructing retaining wall 110, multiple composite organic material fillers 120 and multiple composite acid buffer material fillers 130 are used to fill the roadway in sequence at intervals to completely fill the adit mining roadway 200.

[0051] Specifically, such as Figure 4 As shown, one composite organic material filler 120 and one composite acid buffer material filler 130 are sequentially filled into the roadway; wherein, the composite organic material filler 120 is in contact with the retaining wall 110. Then, the remaining composite organic material fillers 120 and composite acid buffer material fillers 130 are sequentially and alternately filled into the adit mining roadway 200, forming a multi-level heavy metal control barrier. That is to say, as... Figure 4As shown, a composite organic material filling body 120 is first filled into the roadway, and then a composite acid buffer material filling body 130 is filled, to form a heavy metal control barrier, wherein the composite organic material filling body 120 is in contact with the retaining wall 110, and then a composite organic material filling body 120 is filled, and then a composite acid buffer material filling body 130 is filled, and so on, to form the heavy metal control barrier, so as to fill the flat-in mining roadway 200.

[0052] Further specifically, the plurality of composite organic material filling bodies 120 and the plurality of composite acid buffer material filling bodies 120 are sequentially filled from the inside of the flat-in mining roadway 200 to the outside thereof. That is, the filling is performed from the end where the retaining wall 110 is arranged, to the mine entrance.

[0053] It should be noted that the number of the composite organic material filling body 120 and the composite acid buffer material filling body 130 is not specifically limited in the embodiment, and can be selected according to actual needs.

[0054] It should be further noted that, in the embodiment, the composite acid buffer material filling body 130 is made of carbonate rock material. The composite organic material filling body 120 is made of modified limestone, attapulgite, iron powder, activated carbon and straw material. The materials of the composite organic material filling body 120 and the composite acid buffer material filling body 130 are not specifically limited in the embodiment, and can be selected according to actual needs.

[0055] The carbonate rock has good neutralization capacity for acid mine drainage containing iron, antimony and arsenic, and can effectively induce Fe to co-precipitate with Sb and As to remove them from water. The AMD secondary iron sludge generated by the neutralization reaction of the carbonate rock is more likely to be transformed into goethite in an acid environment, and the structure is not easy to change in a weak alkaline environment, and the environmental stability is good.

[0056] After the reaction of the carbonate rock with the acid mine drainage, a layer of AMD secondary iron sludge filter membrane mainly composed of goethite, siderite and gypsum is formed on the surface of the carbonate rock, which can adsorb heavy metals. The AMD secondary iron sludge precipitated in the device is mainly in the form of flocculent structure of granular particles of poorly crystalline amorphous hydrated iron oxide such as goethite and siderite, which has good adsorption effect on metal ions.

[0057] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal control barrier according to the embodiments of the present disclosure makes full use of the roadway space, and couples and connects multiple composite organic material filling bodies such as modified limestone, attapulgite, iron powder, activated carbon and matrix package together in the composite acid buffer material filling body in which carbonate rock is the main filling material, so as to increase the water flow path and water-rock reaction time, and to adsorb dissolved iron, manganese and sulfide in the water body through adsorption and co-precipitation, so as to promote water purification. In addition, the composite acid buffer material filling body and the composite organic material filling body are made of natural and non-polluted materials, thereby saving cost.

[0058] In the present embodiment, the process in which the composite organic material filling body 120 reacts with the mine wastewater is as follows:

[0059] The mine wastewater flows out from the top gap of the retaining wall 110, and the composite organic material filling body 120 reacts with the flowing-out mine wastewater to increase the pH value of the mine wastewater and remove metal ions in the mine wastewater.

[0060] Specifically, after the mine wastewater flows out from the top gap of the retaining wall 110, the mine wastewater contacts the composite organic material filling body 120, the composite organic material filling body 120 provides nutrients for microorganisms in the mine wastewater, and through the action of sulfate-reducing bacteria in the composite organic material filling body 120, the sulfate participates in the reduction reaction, the pH value of the mine wastewater is increased, the sulfate is removed at the same time, the metal ions such as iron and manganese in the mine wastewater are removed, the concentration of heavy metals in the mine wastewater is effectively controlled, and the heavy metal pollutants in the mine wastewater are reduced.

[0061] In the present embodiment, the process in which the composite acid buffer material filling body 130 reacts with the mine wastewater is as follows:

[0062] After the mine wastewater flows out from the top gap of the retaining wall 110, the mine wastewater contacts and reacts with the composite acid buffer material filling body 130, and through the reaction between the carbonate rock in the composite acid buffer material filling body 130 and the acid mine wastewater, the pH value of the mine wastewater is increased, and at the same time, the precipitate generated by the reaction between the composite acid buffer material filling body 130 and the mine wastewater fills the gap in the composite acid buffer material filling body 130, so that the composite acid buffer material filling body 130 closely covers the original exposed ore-bearing rock and surrounding rock, that is, the composite acid buffer material filling body 130 is integrated with the original exposed ore-bearing rock and surrounding rock, and with the continuous reaction, the heavy metal pollutants in the mine wastewater can be greatly reduced.

[0063] As Figure 4As shown, in the embodiment, the composite acid-buffering material filling body 130 includes a first composite acid-buffering material layer 131 and a second composite acid-buffering material layer 132, and the second composite acid-buffering material layer 132 is arranged above the first composite acid-buffering material layer 131. The particle size of the second composite acid-buffering material layer 132 is greater than the particle size of the first composite acid-buffering material layer 131.

[0064] The first composite acid-buffering material layer 131 at the bottom has a smaller particle size, smaller gaps between adjacent particles, and slower flow of mine wastewater through the first composite acid-buffering material layer 131, so that the mine wastewater can fully react with the first composite acid-buffering material layer 131, and the precipitate generated after the reaction of the first composite acid-buffering material layer 131 and the mine wastewater can better fill the gaps of the first composite acid-buffering material layer 131, so that the first composite acid-buffering material layer 131 can better integrate with the original exposed ore-bearing rock stratum and surrounding rock surface.

[0065] The second composite acid-buffering material layer 132 above the first composite acid-buffering material layer 131 has a larger particle size and a larger gap between adjacent particles, which can facilitate the flow of mine wastewater, that is, the second composite acid-buffering material layer 132 provides a channel for the flow of mine wastewater.

[0066] In the embodiment, the particle size of the first composite acid-buffering material layer 131 ranges from 30 mm to 40 mm, and specifically, the particle size of the first composite acid-buffering material layer 131 is 36 mm. The first composite acid-buffering material layer 131 is mainly used to react with mine wastewater, so its particle size needs to be set larger. Specifically, the particle size of the first composite acid-buffering material layer 131 can be set according to actual needs, and the embodiment does not make specific limitations.

[0067] The particle size of the second composite acid-buffering material layer 132 ranges from 25 mm to 35 mm. Specifically, the particle size of the second composite acid-buffering material layer 132 is 30 mm. The second composite acid-buffering material layer 132 provides a channel for the flow of mine wastewater while reacting with mine wastewater, so its particle size does not need to be too large. Specifically, the particle size of the second composite acid-buffering material layer 132 can be set according to actual needs, and the embodiment does not make specific limitations.

[0068] In the embodiment, the ratio of the composite organic material filling body 120 to the composite acid-buffering material filling body 130 is 1:3, and the composite organic material filling body 120 and the composite acid-buffering material filling body 130 are closely distributed.

[0069] It should be noted that the ratio of the composite organic material filling body 120 and the composite acid buffer material filling body 130 and the corresponding filling distance can be set according to the concentration of the pollutants and the pH value of the mine wastewater, and the present embodiment is not limited in this regard, and the selection can be made according to actual needs.

[0070] In S130, the filled roadway is sealed to completely immerse the composite organic material filling body and the composite acid buffer material filling body in the mine wastewater, so that the mine wastewater is fully reacted.

[0071] Specifically, after the filling of the roadway is completed, a sealing wall (not shown in the figure) is used to seal the end of the completed flat drift mining roadway 200, wherein the height of the sealing wall is lower than the height of the flat drift mining roadway 200, that is, there is a gap between the top of the sealing wall and the top of the roadway. In the present embodiment, the sealing wall can be a steel concrete wall, and of course other walls can also be used, and the present embodiment is not limited in this regard, and the selection can be made according to actual needs. The sealing wall is arranged on the completed flat drift mining roadway 200, so that the composite organic material filling body 120 and the composite acid buffer material filling body 130 are completely immersed in the mine wastewater, so that the mine wastewater is fully reacted.

[0072] Specifically, as the composite acid buffer material filling body 130 continuously reacts with the mine wastewater, the generated precipitate continuously flows to the entrance of the roadway, and after being intercepted by the sealing wall and the composite acid buffer material filling body 130, it continuously fills the pores of the composite acid buffer material filling body 130 and the sealing wall. Eventually, only a small part of the mine wastewater flows out of the abandoned mine after overflowing from the top of the sealing wall, and most of the mine wastewater is intercepted and continuously reacts with the composite acid buffer material filling body 130, so that the composite acid buffer material filling body 130 is integrated with the original exposed ore-bearing rock and surrounding rock, and the inside of the roadway becomes an anaerobic environment, and is restored to the state before the roadway is mined, further blocking the precipitation of metal substances in the ore deposit, and further reducing the heavy metal pollutants in the mine wastewater. In addition, the heavy metal in the mine wastewater is controlled while the roadway is filled, which saves costs.

[0073] As shown in Table 1, the initial mine wastewater in the flat drift mining roadway 200 has a low pH value, and the Fe concentration, Sb concentration and As concentration are high. From Figure 5 It can be seen that after the mine wastewater in the roadway is treated by the multi-stage heavy metal control barrier, the pH of the treated mine wastewater is greater than 7, showing the stability and durability of the carbonate rock neutralization effect. The overall removal effect of heavy metal ions gradually increases with time, and the removal rate of Fe is close to 99.9%, and the removal rates of Sb and As are about 76% and 93% respectively.

[0074] From Table 1 andFigure 4 It can be seen that, in the embodiment, the method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier can well achieve in-situ inhibition of release of heavy metal pollutants, blockage of migration of heavy metals, direct governance of mine wastewater in the roadway, obvious governance effect, no need for maintenance, cost saving, reduced impact of treated mine wastewater on groundwater around the mining area, and significant reduction in discharge of mine wastewater containing heavy metal ions, and reduced environmental pressure.

[0075] Table 1: Initial acid mine wastewater quality indicators in the roadway (unit: μg / L)

[0076]

[0077] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier according to the embodiment of the present disclosure reduces the oxygen content in the roadway by long-distance filling of the roadway, builds an anaerobic environment in the roadway, and inhibits the oxidation of sulfides to reduce the generation of high-concentration acid mine wastewater. At the same time, after long-distance filling of the roadway, the groundwater flow rate in the roadway is slowed down, and the dissolved iron, manganese, and sulfides formed by oxidation of sulfides are precipitated into secondary minerals such as iron-manganese oxides, hydroxyl ferric oxide, and schulteite, thereby reducing the pollutant content in water discharge.

[0078] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier according to the embodiment of the present disclosure blocks the main outflow of mine wastewater in the intercepting adit mining roadway, raises the liquid level of mine wastewater in the roadway, keeps the exposed ore-bearing rock stratum and surrounding rock surface below the liquid level of mine wastewater in an anaerobic state, preliminarily blocks the precipitation of metal ions in the exposed ore-bearing rock stratum and surrounding rock surface, and reduces heavy metal pollutants in acid mine wastewater.

[0079] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier according to the embodiment of the present disclosure fills multiple composite organic material filling bodies and multiple composite acid buffer material filling bodies in the roadway in sequence and at intervals, reacts the composite organic material filling bodies with mine wastewater to effectively remove metal ions in the mine wastewater and control the concentration of heavy metals in the mine wastewater while improving the pH value of the mine wastewater, and reacts the composite acid buffer material filling bodies with mine wastewater to generate precipitates that fill the gaps in the composite acid buffer material filling bodies, so that the composite acid buffer material filling bodies tightly wrap the exposed ore-bearing rock stratum and surrounding rock surface in the roadway, thereby effectively blocking and controlling the water-rock reaction process in the roadway and greatly reducing the amount of pollutants generated in the mine wastewater.

[0080] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier according to the embodiments of the present disclosure blocks the roadway after filling to fully immerse the composite organic material filling body and the composite acid buffer material filling body in the mine wastewater, so that the mine wastewater fully reacts with the mine wastewater, and most of the mine wastewater continuously reacts with the composite acid buffer material filling body after being intercepted, so that the exposed ore-bearing rock stratum and surrounding rock surface below the mine wastewater level remains in an anaerobic state, which can further block the precipitation of metal ions in the exposed ore-bearing rock stratum and surrounding rock surface, greatly reducing the amount of pollutants in the mine wastewater.

[0081] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier according to the embodiments of the present disclosure blocks the roadway after filling to fully immerse the composite organic material filling body and the composite acid buffer material filling body in the mine wastewater, so that the mine wastewater fully reacts with the mine wastewater, and most of the mine wastewater continuously reacts with the composite acid buffer material filling body after being intercepted, so that the exposed ore-bearing rock stratum and surrounding rock surface below the mine wastewater level remains in an anaerobic state, which can further block the precipitation of metal ions in the exposed ore-bearing rock stratum and surrounding rock surface, greatly reducing the amount of pollutants in the mine wastewater.

[0082] The method for treating mine wastewater in a roadway by using a multi-stage heavy metal blocking and controlling barrier according to the embodiments of the present disclosure blocks the roadway after filling to fully immerse the composite organic material filling body and the composite acid buffer material filling body in the mine wastewater, so that the mine wastewater fully reacts with the mine wastewater, and most of the mine wastewater continuously reacts with the composite acid buffer material filling body after being intercepted, so that the exposed ore-bearing rock stratum and surrounding rock surface below the mine wastewater level remains in an anaerobic state, which can further block the precipitation of metal ions in the exposed ore-bearing rock stratum and surrounding rock surface, greatly reducing the amount of pollutants in the mine wastewater.

[0083] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the embodiments of the present disclosure, but the embodiments of the present disclosure are not limited thereto. Those skilled in the art can make various modifications and improvements without departing from the spirit and essence of the embodiments of the present disclosure, and these modifications and improvements are also considered within the protection scope of the embodiments of the present disclosure.

Claims

1. A method for in-mine wastewater treatment using a multi-stage heavy metal barrier, characterized in that, The method comprises: intercepting the main stream of mine wastewater in the adit mining roadway to raise the liquid level of the mine wastewater in the roadway, so that the ore-bearing rock stratum and surrounding rock surface exposed below the liquid level of the mine wastewater remain in an anaerobic state; wherein, the roadway is provided with a retaining wall at the end far from the roadway portal; wherein, the height of the retaining wall is lower than the height of the roadway; filling a plurality of composite organic material filling bodies and a plurality of composite acid buffer material filling bodies in the roadway in sequence and at intervals, the composite organic material filling bodies and the composite acid buffer material filling bodies being closely distributed to react with the mine wastewater respectively, specifically comprising: the mine wastewater flows out from the top gap of the retaining wall; the composite acid buffer material filling body reacts with the flowing mine wastewater to increase the pH value of the mine wastewater, and the precipitate generated by the reaction fills the gap in the composite acid buffer material filling body, so that the composite acid buffer material filling body closely covers the original exposed ore-bearing rock stratum and surrounding rock surface; the filled roadway is blocked to completely immerse the composite organic material filling body and the composite acid buffer material filling body in the mine wastewater, so that they fully react with the mine wastewater, so that the composite acid buffer material filling body is integrated with the original exposed ore-bearing rock stratum and surrounding rock, so that the roadway becomes an anaerobic environment and is restored to the state before mining; wherein, the composite acid buffer material filling body comprises a first composite acid buffer material layer and a second composite acid buffer material layer; the second composite acid buffer material layer is arranged above the first composite acid buffer material layer; wherein, the particle size of the second composite acid buffer material layer is greater than that of the first composite acid buffer material layer; the composite acid buffer material filling body comprises a carbonate rock material; the composite organic material filling body comprises modified limestone, attapulgite, iron powder, activated carbon and straw material.

2. The method of claim 1, wherein, the filling of the plurality of composite organic material filling bodies and the plurality of composite acid buffer material filling bodies in the roadway in sequence and at intervals to react with the mine wastewater respectively comprises: the mine wastewater flows out from the top gap of the retaining wall; the composite organic material filling body reacts with the flowing mine wastewater to increase the pH value of the mine wastewater and remove metal ions in the mine wastewater.

3. The method of claim 1, wherein, the filling of the plurality of composite organic material filling bodies and the plurality of composite acid buffer material filling bodies in the roadway in sequence and at intervals to react with the mine wastewater respectively comprises: one of the composite organic material filling bodies and one of the composite acid buffer material filling bodies are filled in the roadway in sequence; wherein, the composite organic material filling body is in contact with the retaining wall; the remaining plurality of composite organic material filling bodies and the composite acid buffer material filling bodies are filled in the roadway in sequence and at intervals to form a heavy metal control barrier.

4. The method according to any one of claims 1 to 3, characterized in that, the filling of the plurality of composite organic material filling bodies and the plurality of composite acid buffer material filling bodies in the roadway in sequence and at intervals to react with the mine wastewater respectively further comprises: The plurality of composite organic filling bodies and the plurality of composite acid buffer filling bodies are sequentially filled from the inside of the roadway to the outside of the roadway.

5. The method according to any one of claims 1 to 3, characterized in that, The filled roadway is sealed, comprising: The filled roadway is sealed by a sealing wall, wherein the height of the sealing wall is lower than the height of the roadway.

6. The method according to any one of claims 1 to 3, characterized in that, The particle size range of the first composite acid buffer material layer is 30mm-40mm. The particle size range of the second composite acid buffer material layer is 25mm-35mm.

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