Device for simulation and real-time monitoring of migration and transformation of heavy metals in tailings and application of device

Abstract

The invention discloses a device for simulating the migration and transformation process of tailings heavy metal and application of the device, and belongs to the mine environment protection simulation research technology. The device comprises a leaching column, a liquid storage system, a weathering simulation system, a collection and detection unit and a data acquisition and control system; release, migration and transformation of heavy metal can be simulated, the simulated weathering system reproduces the natural weathering process of tailings through an adjustable gas flow rate gas supply pump and a porous gas cake, the liquid storage system accurately controls simulated rainfall through a peristaltic pump, and an oxygen sensitive strip monitors the migration path of oxygen in a leaching column in real time. The technical problem that heavy metal migration and conversion in the natural tailing stockpiling environment are difficult to simulate under the laboratory condition is effectively solved, the experimental period is shortened, the experimental precision is improved, the method is suitable for the field of tailing treatment and environment monitoring, and an efficient experimental tool is provided for research on tailing heavy metal migration and conversion.

Description

Technical Field

[0001] The present application relates to a mining environmental protection simulation research technology, and specifically to a device for simulating and real-time monitoring of the migration and transformation of heavy metals in tailings and its application. Background Art

[0002] During the mining and smelting of mineral resources, heavy metals can enter the surrounding environment through atmospheric deposition, surface water transport (including acid mine drainage) and groundwater leakage. These tailings contain a large amount of heavy metal elements, such as Pb, Zn, Cu, Cd and As. Long-term open-air storage in tailings ponds will pose a serious threat to the environment.

[0003] The migration and transformation process of heavy metals in tailings will not only change with the changes in its own geochemical characteristics, but also be affected by external environmental conditions. Therefore, clarifying the release and migration and transformation mechanism of heavy metals in tailings is of great significance for the control and management of tailings pollution.

[0004] The field test of heavy metal release and migration and transformation in tailings is difficult to operate, expensive and has a long test cycle, which makes it difficult to meet the urgent needs of tailings pollution control and management. Traditional tailings heavy metal migration and transformation experimental devices usually have free seepage holes under the tailings column, which simulate rainfall or tracer solution injected into the tailings column and then seep downward. Due to the small particle size of tailings / tailings, blockage often occurs during the experiment, resulting in slow progress and inaccurate results.

[0005] The methods in the prior art are deficient in simulating the actual tailings storage environment and are unable to simulate the complex hydrogeochemical conditions in the tailings pond. In addition, the experimental data cannot be processed in real time, resulting in similar experimental results having no guiding value. In addition, the experimental cycle is long and the accuracy of the experimental results cannot be guaranteed. Summary of the invention

[0006] Based on the needs of the above-mentioned fields, the present invention provides an experimental model construction and application for the migration and transformation of heavy metals in tailings, which solves or partially solves the problem that the methods in the prior art cannot simulate the release and migration and transformation of heavy metals in tailings in the actual storage environment of tailings ponds, resulting in unscientific test results, long experimental cycles, and the authenticity and accuracy of the experiments cannot be verified. The technical effects of short test cycles, small experimental errors, high test accuracy and dynamic monitoring of the release and migration and transformation processes of heavy metals in tailings are achieved, as described below.

[0007] A device for simulating and real-time monitoring the migration and transformation of heavy metals in tailings, characterized by comprising:

[0008] The elution column 1 is a hollow tube with a detachable top cover 2 and a porous bottom cover 3 at both ends; a top liquid inlet 4 is provided on the surface of the top cover 2; detection ports and a fixture 5 installed on the detection ports are provided at multiple positions at different heights on the column wall of the elution column 1, and the fixture 5 is used to connect the side wall collection and detection unit; a bottom detection port is provided below the porous bottom cover 3 for installing the bottom collection and detection unit;

[0009] The simulated weathering system includes an adjustable gas flow rate air supply pump 6 and a porous gas cake 7; the porous gas cake 7 is arranged on the porous bottom cover 3, and its edge is in close contact with the inner wall of the leaching column, and the adjustable gas flow rate air supply pump is used to transport gas to the porous gas cake 7 to ensure that the gas is evenly distributed in the leaching column 1;

[0010] The collecting and detecting unit includes the side wall collecting and detecting unit and the bottom collecting and detecting unit. Each of the collecting and detecting units has a sampling tube, a filter 8, a flow meter 9, a solenoid valve 10 and a collecting device. One end of the sampling tube is connected to the leaching column 1, and the other end extends into the collecting device.

[0011] The inner side wall of the leaching column 1 is also provided with an oxygen sensitive strip 11 for monitoring oxygen migration.

[0012] Preferably, the porous gas cake 7 is made of stone, ceramic, metal, polymer or sintered glass and has evenly distributed micropores; and the porous gas cake is provided with a plurality of large holes, which have the same diameter as the holes on the porous bottom cover 3 and correspond in position to each other, so as to facilitate the flow of the leachate.

[0013] Preferably, the collecting device is a sampling bottle 12; the interior of the sampling bottle 10 is provided with a pH electrode 13, a conductivity electrode 14, a dissolved oxygen electrode 15, a redox potential electrode 16 and a heavy metal electrode 17; the heavy metal electrode 17 is configured to improve the electrode performance by modifying different electrode materials, thereby improving the detection capability of heavy metals.

[0014] Preferably, the above device also includes a data acquisition and control system; it has the same number of data collectors 18 as the collection and detection units, and at least one remote processing and transmission unit;

[0015] Each of the data collectors 18 is respectively connected to the pH electrode 13, the conductivity electrode 14, the dissolved oxygen electrode 15, the redox potential electrode 16 and the heavy metal electrode 17 in one of the sampling bottles 12 through wires;

[0016] The remote processing transmission unit is electrically connected to the oxygen sensitive strip 11 and each data collector 18 respectively;

[0017] The remote processing and transmission unit is a data collection controller 19; its input end is connected to the data collector 18 for receiving and processing data obtained from various electrodes; its output end is connected to the data terminal 20 for displaying and storing data;

[0018] The device includes 6 sets of the collection and detection units and 6 data collectors 18.

[0019] Preferably, the device further comprises a leaching support 21, which is a frame structure including a supporting surface, the supporting surface is provided with an embedding groove 22 for detachably installing the leaching column 1, and a leaching support funnel 23 is also provided under the supporting surface. This design is different from the existing integrated design, and is convenient for dismantling and sampling of solid samples after the test.

[0020] Preferably, the liquid storage system comprises: a leaching solution storage tank 24 connected to the top liquid inlet 4 through a pipeline; a peristaltic pump 25, arranged on the pipeline between the leaching solution storage tank 24 and the leaching column 1, for accurately controlling the delivery frequency of the leaching solution.

[0021] Preferably, both ends of the tube body of the leaching column 1 have an integrally formed top ring plate 26 and a bottom ring plate 27 extending inwardly to form an inner hole; the top cover 2 is arranged above the top ring plate 26; and the porous bottom cover 3 is arranged above the bottom ring plate 27.

[0022] Preferably, the leaching column 1 is a hollow cylindrical structure, and at least one sealing kit is respectively provided at the connection points at both ends; the sealing kit is in a circular shape, and there are two sealing kits in total, one of which is located between the top cover 2 and the top ring plate 26, and the other sealing kit is located between the porous bottom cover 3 and the bottom ring plate 27.

[0023] Another aspect of the present application is to provide a method for simulating and real-time monitoring the migration and transformation of heavy metals in tailings based on the above-mentioned device, characterized in that any one of the above-mentioned devices is used, including the following operating steps:

[0024] Step 1, the porous gas cake 7 is tightly attached to the porous bottom cover 3, and the holes of the two are matched one by one, and then placed on the inner wall of the leaching column 1 and the upper surface of the bottom ring plate 27, and the oxygen sensitive strip 11 is attached to the inner wall of the leaching column 1, and the gauze, quartz sand layer and tailings are filled in the leaching column 1 in turn to form a tailings filling column, and the top cover 2 is closed and fixed;

[0025] Step 2. Install a connection collection detection unit at the side wall detection port and the bottom detection port of the leaching column 1;

[0026] Step 3, start the simulated weathering system, and deliver gas to the porous gas cake 7 through the air supply pump 6 to ensure that the gas is evenly distributed in the leaching column 1 to simulate the release and migration and transformation process of heavy metals in the tailings under weathering conditions;

[0027] Step 4: injecting leaching solution into the leaching column 1 through the peristaltic pump 25, controlling the leaching solution to penetrate evenly in the tailings filling column to simulate the release and migration of heavy metals under rainfall conditions;

[0028] Step 5, collecting and detecting tailings leachate at different heights in real time, removing impurities using a filter 13, measuring the volume of the leachate through a flow meter 12, and sequentially entering a collection device through an electromagnetic valve 11, and measuring the pH, conductivity, dissolved oxygen, redox potential and heavy metal concentration of the leachate at each height in real time;

[0029] Step 6: The data acquisition device 18 collects various test data of the effluent entering the collection device during the leaching process in real time, processes and summarizes them through the data collection controller 19, and finally transmits them to the data terminal 20 for storage, real-time analysis and display, so as to realize real-time monitoring and recording of the entire leaching process.

[0030] Preferably, in the above method, the ratio of height to diameter of the tailings filling column is greater than 1:2.5 to avoid preferential flow;

[0031] A layer of gauze is placed on the porous air cake and then filled with quartz sand, wherein the thickness of the quartz sand is 1 cm;

[0032] The preferred flow refers to the fact that when the liquid flows in the tailings filling column, it tends to pass quickly along the channel with small resistance and bypass other areas with large resistance, resulting in uneven flow.

[0033] Preferably, the tailings are selected from one or more of the following: sulfide tailings, carbonate tailings, oxide tailings, silicate tailings, phosphate tailings, bauxite tailings, gangue tailings and manganese ore tailings. The method and device of the present invention can be used for the simulation of various tailings.

[0034] This application has at least the following beneficial technical effects:

[0035] The present invention designs a liquid storage system including a leaching column 1, a leaching solution storage tank 25 and a peristaltic pump 24 to control the changes in simulated precipitation, and designs a simulated weathering system including an adjustable gas flow rate air supply pump 6 and a porous gas cake 7 to reproduce the change process in the natural environment of tailings, thereby greatly shortening the test cycle, solving the problem in the prior art that it is impossible to simulate the release and migration and transformation of heavy metals in tailings in the actual storage environment of the tailings pond, and at the same time solving the problems of long test cycle and lack of reliability of experimental results.

[0036] The present invention is equipped with multiple sets of collection and detection units, including a holder 5, a sampling bottle 12, a pH electrode 13, a conductivity electrode 14, a dissolved oxygen electrode 15, a redox potential electrode 16 and a heavy metal electrode 17, etc. The oxygen migration path in the leaching column 1 is monitored in real time through the oxygen sensitive strip 11, and the pH, conductivity, dissolved oxygen content, redox potential and heavy metal concentration of the leaching solution are monitored in real time through the data acquisition and control system (data acquisition device 18 and data collection controller 19), providing key data support for the prediction of tailings heavy metal pollution migration and the optimal design of tailings treatment technology.

[0037] The device of the present invention can simulate the influence of various environmental conditions (such as pH value, redox potential, etc.) on the migration and transformation of heavy metals in tailings, and is particularly suitable for simulating the migration behavior of heavy metals under different weathering conditions during tailings storage. It can be widely used in the design and optimization of tailings field restoration and management plans, providing scientific basis and technical support.

[0038] The present invention integrates the storage, collection, detection and data acquisition functions of the leachate, has a compact structure and is easy to operate. It not only optimizes the test parameters for the establishment of the tailings heavy metal release and migration transformation test model, improves the test accuracy, and makes the research results more scientific and reliable, but also can achieve real-time and efficient monitoring of the heavy metal release and migration transformation process in the tailings. The equipment can be widely used in a variety of tailings treatment and environmental monitoring fields, especially in the fields of environmental science and engineering, mine environmental management and geochemical research, especially in the evaluation of tailings yard restoration technology, heavy metal pollution migration prediction and optimization design of tailings treatment technology. It has important application value, provides a scientific basis for the establishment of the test model, and further ensures the reliability of the research results. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the overall structure of the device used for simulating and real-time monitoring of the migration and transformation of heavy metals in tailings in this application.

[0040] Figure 2 It is a schematic diagram of the structure of the leaching column and the bracket of the device used for simulating and real-time monitoring the migration and transformation of heavy metals in tailings in the present application;

[0041] Figure 3 This is the XRD diagram of the effect of different leaching solutions on the mineral content of tailings when the weathering system is turned on and off in the device used for simulating the migration and transformation of heavy metals in tailings and real-time monitoring of the present application.

[0042] Wherein: 1- leaching column, 2- top cover, 3- porous bottom cover, 4- liquid inlet, 5- holder, 6- air supply pump, 7- porous gas cake, 8- filter, 9- flow meter, 10- solenoid valve, 11- oxygen sensitive strip, 12- sampling bottle, 13- pH electrode, 14- conductivity electrode, 15- dissolved oxygen electrode, 16- redox potential electrode, 17- heavy metal electrode, 18- data acquisition device, 19- data collection controller, 20- data terminal, 21- bracket funnel, 22- embedded groove, 23- bottom ring plate, 24- peristaltic pump, 25- leaching solution storage tank, 26- top ring plate, 27- bottom ring plate. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application.

[0044] The following is combined with Figure 1 and Figure 2 The device for simulating and monitoring the migration and transformation of heavy metals in tailings of the present application is described as an example, but it is not intended to limit the scope of protection of the invention.

[0045] like Figure 1 and Figure 2 As shown, all embodiments of the present invention provide a device for simulating and real-time monitoring of tailings heavy metal migration and transformation, comprising: a leaching column 1, which is a hollow tube with a detachable top cover 2 and a porous bottom cover 3 at both ends; a top liquid inlet 4 is provided on the surface of the top cover 2; detection ports are provided at multiple positions at different heights on the column wall of the leaching column 1 and a fixture 5 installed on the detection port, and the fixture 5 is used to connect the side wall collection detection unit; a bottom detection port is provided below the porous bottom cover 3 for installing the bottom collection detection unit;

[0046] The simulated weathering system includes an adjustable gas flow rate air supply pump 6 and a porous gas cake 7; the porous gas cake 7 is arranged on the porous bottom cover 3, and the adjustable gas flow rate air supply pump is used to transport gas to the porous gas cake 7 to ensure that the gas is evenly distributed in the leaching column 1;

[0047] The collecting and detecting unit includes the side wall collecting and detecting unit and the bottom collecting and detecting unit. Each of the collecting and detecting units has a sampling tube, a filter 8, a flow meter 9, a solenoid valve 10 and a collecting device. One end of the sampling tube is connected to the leaching column 1, and the other end extends into the collecting device.

[0048] The inner side wall of the leaching column 1 is also provided with an oxygen sensitive strip 11 for monitoring oxygen migration.

[0049] In a preferred embodiment, the collecting device is a sampling bottle 12; the interior of the sampling bottle 10 is provided with a pH electrode 13, a conductivity electrode 14, a dissolved oxygen electrode 15, a redox potential electrode 16 and a heavy metal electrode 17; the heavy metal electrode 17 is configured to improve the electrode performance by modifying different electrode materials, thereby improving the detection capability of heavy metals.

[0050] In a preferred embodiment, the above device further comprises a data acquisition and control system; it has the same number of data collectors 18 as the collection and detection units, and at least one remote processing and transmission unit;

[0051] Each data collector 18 is respectively connected to a pH electrode 13, a conductivity electrode 14, a dissolved oxygen electrode 15, a redox potential electrode 16 and a heavy metal electrode 17 in a sampling bottle 12 through wires;

[0052] The remote processing transmission unit is electrically connected to the oxygen sensitive strip 11 and each data collector 18 respectively;

[0053] The remote processing and transmission unit is a data collection controller 19; its input end is connected to the data collector 18 for receiving and processing data obtained from various electrodes; its output end is connected to the data terminal 20 for displaying and storing data;

[0054] In a preferred embodiment, the device further comprises a leaching support 21, which is a frame structure including a support surface, and an embedding groove 22 is provided on the support surface for detachably mounting the leaching column 1. A leaching support funnel 23 is also provided below the support surface, and the discharged liquid flows to the bottom collection detection unit through the funnel outlet. This design is different from the existing integrated design, and is convenient for dismantling and sampling of solid samples after the test.

[0055] In a preferred embodiment, the liquid storage system comprises:

[0056] The eluent storage tank 24 is connected to the top liquid inlet 4 through a pipeline;

[0057] The peristaltic pump 25 is arranged on the pipeline between the elution solution storage tank 24 and the elution column 1, and is used to accurately control the delivery frequency of the elution solution. In order to accurately control the delivery frequency of the elution solution, a peristaltic pump 25 is arranged between the elution solution storage tank 24 and the liquid inlet 4. In addition, the elution solution storage tank 24, the filter 8, various electrochemical sensors (pH electrode 13, conductivity electrode 14, dissolved oxygen electrode 15, redox potential electrode 16, heavy metal electrode 17), oxygen sensitive strip 11 and sampling bottle 12 are all made of acid and alkali corrosion resistant materials to improve the durability and service life of the device.

[0058] In a preferred embodiment, the leaching column 1 is a hollow cylindrical tube with open ends, and its top and bottom edges extend inward, forming a top ring plate 26 and a bottom ring plate 27 in an integral manner. An oxygen sensitive strip 11 is attached to the inner wall of the leaching column 1 to monitor the migration of internal oxygen. A top cover 2 is detachably provided above the top ring plate 26, and a liquid inlet 4 is provided on the surface of the top cover 2; a porous bottom cover 3 is detachably provided above the bottom ring plate 27, and a bottom detection port is provided below the bottom cover 3 for installing a bottom collection detection unit. To ensure the sealing effect.

[0059] In a preferred embodiment, a sealing kit is provided at each connection of the leaching column 1, for a total of two sealing kits; each sealing kit is annular, one sealing kit is provided between the top cover 2 and the top ring plate 26, and the other sealing kit is provided between the porous bottom cover 3 and the bottom ring plate 27.

[0060] In a preferred embodiment, in order to further monitor the solution parameters and oxygen migration path data in the leaching column 1 to ensure comprehensive data collection and accuracy at different depths, a plurality of fixtures 5 are evenly and vertically distributed along the axial direction on the outside of the leaching column 1. Each fixture 5 penetrates into the interior of the leaching column 1 and is connected to an independent side wall collection and detection unit through a pipeline.

[0061] The connection method between the top cover 2 and the leaching column 1 can be selected according to actual needs, such as threaded connection, snap connection, etc. In this embodiment, the outer ring edge of the top ring plate 26 extends vertically upward along the central axis direction to form a groove area with the top ring plate 26 as the bottom. The top cover 2 is fixed in the groove by the elastic stress of the material, thereby achieving a stable connection. In addition, the leaching column 1, the top cover 2 and the porous bottom cover 3 are all made of transparent polymethyl methacrylate material to ensure visibility during the experiment.

[0062] In a preferred embodiment, the porous gas cake 7 is made of stone, ceramic, metal, polymer or sintered glass and has uniformly distributed micropores; and the porous gas cake is provided with a plurality of large holes, which are the same diameter as the holes on the porous bottom cover 3 and correspond in position to facilitate the flow of leachate. The air supply pump 6 is connected to the porous gas cake 7 through a conduit to control the gas flow rate and ensure that the gas can be evenly transported to each part of the leaching column 1, thereby maintaining the consistency of the experimental environment. In addition, the holes on the porous gas cake 7 correspond to the holes on the porous bottom cover 3 in diameter and position, ensuring that the gas is uniformly diffused inside the leaching column 1 while ensuring that the leachate inside the equipment can be discharged downward normally. The advantage of this design is that it can systematically simulate the weathering process of tailings in an actual storage environment in the laboratory, and simulate the gas flow and distribution under natural conditions by accurately adjusting the gas flow rate and evenly distributing oxygen. In the tailings pond, the tailings are exposed to the air for a long time, contacted with environmental factors such as oxygen and moisture, and undergo weathering. This process will change the mineral structure and chemical properties of the tailings, especially under the action of oxygen, the oxidation reaction of sulfide minerals will be accelerated, producing acidic substances such as sulfuric acid, which will cause the heavy metal ions in the tailings to dissolve and be released into the environment, causing heavy metal pollution. Through this simulated weathering system, the weathering process under these environmental conditions can be reproduced in the laboratory. The porous gas cake 7 ensures the uniform distribution of oxygen inside the leaching column 1, and the air supply pump 6 ensures that the gas enters the system at a controlled flow rate, so that the weathering is carried out under controlled conditions, thereby ensuring the reliability and repeatability of the experimental results. This system helps to study the heavy metal release mechanism and migration path of tailings under different weathering conditions, and provides a scientific basis for tailings pond management and environmental protection. In addition, the system can also simulate various chemical reactions such as hydrolysis and carbonation that occur during weathering, and through in-depth analysis of the chemical changes in these processes, it helps to formulate more effective pollution prevention and control measures, and further improve the scientificity and environmental protection effects of tailings pond management.

[0063] It is understandable that a temperature control device can be added to the existing liquid storage system to adjust the temperature of the leaching solution entering the leaching column 1, thereby simulating the leaching process under different ambient temperatures during the experiment. This improved design should also be considered within the above protection scope.

[0064] Experimental procedures

[0065] Step 1: The porous gas cake 7 is tightly attached to the porous bottom cover 3, so that the holes on the two correspond to each other, and then placed on the inner wall of the leaching column 1 and the upper surface of the bottom ring plate 27 to ensure that the gas will not leak during the transportation process and can be evenly distributed in various parts of the leaching column 1. At the same time, the oxygen sensitive strip 11 is attached to the inner side wall of the leaching column 1 and connected to the input end of the data collection controller 19. At least one layer of gauze and a 1 cm thick evenly distributed quartz sand layer are placed on the top of the porous gas cake 7 in turn to form a good filtering foundation.

[0066] Next, fill the tailings into the leaching column 1 to form a tailings filling column, and ensure that the height to diameter ratio of the tailings filling column is greater than 1:2.5. Finally, fix the top cover 2 to the top of the leaching column 1 through the sealing kit, and connect the liquid inlet 4 to the peristaltic pump 25 and the leaching solution storage tank 24.

[0067] The above tailings include a mixture of one or more of the following: sulfide tailings, carbonate tailings, oxide tailings, silicate tailings, phosphate tailings, bauxite tailings, gangue tailings and manganese ore tailings.

[0068] In addition, the present invention has found through experimental tests that maintaining the height to diameter ratio of the tailings filling column greater than 1:2.5 can avoid dominant flow to the greatest extent. Preferential flow refers to the tendency of liquid to quickly pass along channels with less resistance (including areas with lower friction resistance, viscosity resistance, local resistance, pore resistance, gravity, etc.) when flowing in the tailings filling column, and bypass other areas with greater resistance, thereby causing uneven flow.

[0069] Step 2: Install the connection collection detection unit at the side wall detection port and the bottom detection port of the leaching column 1.

[0070] Step 3: Start the simulated weathering system. Start the simulated weathering system, adjust the gas flow rate parameter of the air supply pump 6 to the value required for the experiment, ensure that the gas is evenly distributed inside the leaching column 1 through the porous gas cake 7, and simulate the release and migration transformation process of heavy metals in the tailings under weathering conditions.

[0071] Step 4: Start the leaching system. Start the peristaltic pump 25 and inject the leaching solution into the leaching column 1 through the liquid inlet 4. Ensure that the leaching solution penetrates evenly throughout the height of the tailings column, and monitor the injection speed and volume to prevent overflow.

[0072] Step 5: Collect and detect leachate. Start the collection and detection unit to collect tailings leachate at different heights. The solenoid valve 10 controls the liquid flow direction and enters the sampling bottle 12. The leachate volume is measured by the flowmeter 9 before sampling. The leachate is filtered by the filter 8 to remove particulate impurities. The pH electrode 13, conductivity electrode 14, dissolved oxygen electrode 15, redox potential electrode 16 and heavy metal electrode 17 in the sampling bottle 12 respectively detect the pH, conductivity, dissolved oxygen content, redox potential and heavy metal concentration of the leachate. Clean the sensor and sampling bottle after each sampling to prevent cross contamination.

[0073] Step 6: Data collection and processing. The above detection data is collected in real time by the data collector 18, and the data is transmitted to the data collection controller 19. At the same time, the oxygen sensitive strip 11 monitors the oxygen migration inside the leaching column 1, and transmits the corresponding data to the data collection controller 19. The data collection controller 19 processes, analyzes and summarizes the received data in real time, compares the analysis results with the set standard values, and then transmits the data to the data terminal 20 for data storage, analysis and display, thereby realizing real-time monitoring and recording of the entire leaching process.

[0074] Specific application examples

[0075] After assembling the equipment according to steps 1 and 2 above, set the gas flow rate to 0.21L / min, the leaching solution flow rate to 24mL / h, and run the equipment for 40 days. After the experiment, the analysis of the residual substances in the leaching column showed that the release of heavy metals changed by 2.13% compared with the theoretical prediction. This result also shows that the device can accurately simulate the long-term changes of tailings in the actual environment. It is worth noting that the design of the device allows flexible adjustment of the gas flow rate and the leaching solution flow rate within a large range (for example, more extreme environments accelerate the reaction process) to meet different experimental needs. This flexibility not only expands the scope of application of the device, but also significantly shortens the experimental cycle, allowing researchers to obtain experimental results more quickly.

[0076] like Figure 3 As shown, in the device, under the conditions of opening and closing the simulated weathering system, the seepage of different leaching solutions (simulated acid rain and distilled water) caused significant changes in the mineral composition of the tailings. By comparing the XRD spectra, it can be observed that the characteristic peaks of calcite are significantly attenuated when the simulated weathering system is turned on, indicating that the degree of dissolution of calcite under weathering conditions is greater. This further shows that the weathering simulation function of the device design of the present invention can effectively simulate the mineral weathering process in the field environment, and provides a reliable experimental basis for studying the mineral weathering behavior in the tailings.

[0077] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A device for simulating and real-time monitoring the migration and transformation of heavy metals in tailings, characterized in that: include: The leaching column (1) is a hollow tube body, with a detachable top cover (2) and a porous bottom cover (3) at both ends; a top liquid inlet (4) is arranged on the surface of the top cover (2); detection ports and a fixture (5) installed on the detection ports are arranged at multiple positions at different heights on the column wall of the leaching column (1), and the fixture (5) is used to connect to a side wall collection and detection unit; a bottom detection port is arranged below the porous bottom cover (3) for installing a bottom collection and detection unit; The simulated weathering system comprises an adjustable gas flow rate air supply pump (6) and a porous gas cake (7); the porous gas cake (7) is arranged on the porous bottom cover (3), and the adjustable gas flow rate air supply pump is used to transport gas to the porous gas cake (7) to ensure that the gas is evenly distributed in the leaching column (1); A collection and detection unit, comprising the side wall collection and detection unit and the bottom collection and detection unit, each of the collection and detection units having a sampling tube, a filter (8), a flow meter (9), a solenoid valve (10) and a collection device; one end of the sampling tube is connected to the leaching column (1), and the other end extends into the collection device; The inner side wall of the leaching column (1) is also provided with an oxygen sensitive strip (11) for monitoring oxygen migration.

2. The device according to claim 1, characterized in that The porous gas cake (7) is made of stone, ceramic, metal, polymer or sintered glass and has evenly distributed micropores; and a plurality of large holes are arranged on the porous gas cake, and the holes have the same diameter as the holes on the porous bottom cover (3) and have corresponding positions.

3. The device according to claim 2, characterized in that The collecting device is a sampling bottle (12); The sampling bottle (12) is provided with a pH electrode (13), a conductivity electrode (14), a dissolved oxygen electrode (15), a redox potential electrode (16) and a heavy metal electrode (17); The heavy metal electrode (17) is configured to improve the electrode performance and the detection capability of heavy metals by modifying different electrode materials.

4. The device according to claim 3, characterized in that It also includes a data acquisition and control system; it has the same number of data collectors (18) as the collection and detection units, and at least one remote processing and transmission unit; Each data collector (18) is respectively connected to a pH electrode (13), a conductivity electrode (14), a dissolved oxygen electrode (15), a redox potential electrode (16) and a heavy metal electrode (17) in a sampling bottle (12) via wires; The remote processing transmission unit is electrically connected to the oxygen sensitive strip (11) and each data collector (18) respectively; The remote processing and transmission unit is a data collection controller (19): its input end is connected to the data collector (18) for receiving and processing data obtained from various electrodes; Its output end is connected to a data terminal (20) for signal connection to realize data display and storage; The device comprises at least 6 sets of the collection and detection units and 6 data collectors (18).

5. The device according to claim 1, characterized in that It also comprises a leaching support (21), which is a frame structure including a support surface, wherein the support surface is provided with an embedding groove (22) for detachably mounting the leaching column (1) so as to facilitate removal after use and in-situ sampling of the internal sample; A leaching support funnel (23) is also provided below the support surface.

6. The device according to claim 1, characterized in that The liquid storage system comprises: A leaching solution storage tank (24) is connected to the top liquid inlet (4) through a pipeline; A peristaltic pump (25) is arranged on the pipeline between the leaching solution storage tank (24) and the leaching column (1) and is used to accurately control the delivery frequency of the leaching solution.

7. The device according to claim 1, characterized in that The two ends of the tube body of the leaching column (1) have an integrally formed top ring plate (26) and a bottom ring plate (27) extending inwardly to form an inner hole; the top cover (2) is arranged above the top ring plate (26); and the porous bottom cover (3) is arranged above the bottom ring plate (27).

8. The device according to claim 1, characterized in that The leaching column (1) is a hollow cylindrical structure, and at least one sealing kit is provided at each of the two end connections; the sealing kits are in the shape of a ring, and there are two sealing kits in total, one of which is located between the top cover (2) and the top ring plate (26), and the other of which is located between the porous bottom cover (3) and the bottom ring plate (27).

9. A method for simulating and real-time monitoring the migration and transformation of heavy metals in tailings, characterized in that: The device according to any one of claims 1 to 8 comprises the following steps: Step 1, the porous gas cake (7) is tightly attached to the top of the porous bottom cover (3), and the holes of the two are matched one by one, and then placed on the inner wall of the leaching column (1) and the upper surface of the bottom ring plate (27), and at the same time, the oxygen sensitive strip (11) is attached to the inner wall of the leaching column (1), and the gauze, quartz sand layer and tailings are filled in the leaching column (1) in turn to form a tailings filling column, and the top cover (2) is closed and fixed; Step 2. Installing a connection collection detection unit at the side wall detection port and the bottom detection port of the leaching column (1); Step 3, starting the simulated weathering system, and delivering gas to the porous gas cake (7) through the air supply pump (6), ensuring that the gas is evenly distributed in the leaching column (1), so as to simulate the release and migration and transformation process of heavy metals in the tailings under weathering conditions; Step 4: injecting leaching solution into the leaching column (1) through a peristaltic pump (25), controlling the leaching solution to penetrate evenly in the tailings filling column to simulate the release and migration of heavy metals under rainfall conditions; Step 5, collecting and detecting tailings leachate at different heights in real time, removing impurities using a filter (13), measuring the volume of the leachate using a flow meter (12), and sequentially entering a collection device through an electromagnetic valve (11), and measuring the pH, conductivity, dissolved oxygen, redox potential and heavy metal concentration of the leachate at each height in real time; Step 6: The data acquisition device (18) collects various test data of the effluent entering the collection device during the leaching process in real time, processes and summarizes them through the data collection controller (19), and finally transmits them to the data terminal (20) for storage, real-time analysis and display, so as to realize real-time monitoring and recording of the entire leaching process.

10. The monitoring method according to claim 9, characterized in that: The height to diameter ratio of the tailings filling column is greater than 1:2.5 to avoid preferential flow; A layer of gauze is placed on the porous air cake and then filled with quartz sand, wherein the thickness of the quartz sand is 1 cm; The preferred flow refers to the fact that when the liquid flows in the tailings filling column, it tends to pass quickly along the channel with small resistance and bypass other areas with large resistance, resulting in uneven flow.

11. The monitoring method according to claim 9, characterized in that: The tailings are selected from one or more of the following: sulfide tailings, carbonate tailings, oxide tailings, silicate tailings, phosphate tailings, bauxite tailings, coal gangue tailings and manganese ore tailings.

Images