Method for improving stability of tailing pond dam body by enhancing dehydration and consolidation of tailing sand through electroosmosis

Abstract

The invention discloses a method for enhancing tailing sand dehydration consolidation through electroosmosis to improve the stability of a tailing pond dam body, and belongs to the field of tailing sand dehydration treatment.The method is technically characterized by comprising the steps that a direct-current power source is started, and tailing sand electroosmosis dehydration is started; according to the pH value of the tailing sand solution and the size of the isoelectric point of the tailing sand, the positive and negative electrodes of the electrode plates of the dam body and the mountain body or the positive and negative electrodes of the electrode plates at the top and the bottom are adjusted in real time, so that water flows out from one side close to the dam body during left-right arrangement or flows out from the bottom side of the tailing sand during up-down arrangement.

Description

Technical Field

[0001] The invention relates to the field of tailings sand dehydration treatment, and in particular to a method for improving the stability of a tailings pond dam by electroosmosis-enhanced tailings sand dehydration consolidation. Background Art

[0002] Tailings sand is a kind of waste produced in the mining process, and its components are mainly composed of minerals, water and impurities. Water is an important component of tailings sand, and its content is usually more than 20%.

[0003] Due to the precision and optimization of the mineral processing technology, the particle size of tailings sand is usually 2-42μm, with large specific surface area, complex pore structure, strong charge characteristics, etc., which leads to low hydraulic conductivity and poor drainage capacity. Once too much slurry water enters the tailings pond and fails to be discharged in time, it will cause drastic fluctuations in the dam body's infiltration line and an instantaneous increase in pore water pressure, resulting in the instability of the accumulation dam, threatening the safety of life and property of the mine and downstream residents. Therefore, how to quickly dehydrate high-water content tailings sand is of great significance to protecting the stability of the dam body.

[0004] Tailings sand dewatering generally adopts the following methods:

[0005] (1) Natural sedimentation method: This method has simple process and low equipment cost. However, it has slow sedimentation speed, large floor space, low efficiency and poor effect on fine tailings.

[0006] (2) Mechanical filter press method (such as: CN103301679B, CN111905434B). This method has good separation effect, simple operation, energy saving and environmental protection. However, the equipment cost is high and the maintenance cost is also high. The filter press equipment needs to be inspected and maintained regularly, which increases the operating cost. Moreover, this method has limited processing capacity. For large-scale tailings mountains, multiple devices may need to be operated simultaneously, which increases the difficulty of investment and management. At the same time, the tailings sand after filter pressing still contains a certain amount of water, which cannot achieve the purpose of rapid dehydration.

[0007] (3) Vacuum filtration method: This method has high filtration efficiency and is easy to operate. However, it consumes a lot of energy and requires equipment such as vacuum pumps, which results in high operating costs. The filter medium of this method is easily clogged and needs to be cleaned or replaced regularly, which affects production efficiency. In addition, it has certain requirements on the particle size and properties of the tailings. For some fine particles or highly viscous tailings, the dehydration effect is not good.

[0008] (4) Thermal drying method: This method evaporates water by heating, which can effectively remove water and improve physical properties. However, it is costly and may cause the release of harmful gases, leading to environmental pollution.

[0009] Electroosmosis is also a common dehydration method, which has the characteristics of convenient construction and low cost. However, there is still a lack of relevant research on how to use electroosmosis in tailings sand dehydration and consolidation. Summary of the invention

[0010] In order to solve the problems of poor dehydration effect, slow dehydration speed, high cost and complex process in the current method for rapid dehydration of high-water content tailings sand, the present invention proposes a method for electroosmosis-enhanced tailings sand dehydration consolidation to improve the stability of the tailings pond dam.

[0011] The specific scheme of this application is as follows:

[0012] A method for improving the stability of a tailings pond dam body by electroosmosis-enhanced dehydration and consolidation of tailings sand, wherein the tailings sand is filled between the dam body and the mountain body, and a buried water pipe is buried at the bottom of the tailings sand, comprising the following steps:

[0013] S100, burying the electroosmosis dehydration system: left-right arrangement or top-bottom arrangement;

[0014] The left and right arrangement is: a group of electrode plates are vertically arranged in the tailings sand near the dam body and the mountain body, and the electrode plates near the dam body and the mountain body can be connected to the DC power supply;

[0015] The upper and lower arrangement is: a group of electrode plates are horizontally arranged at the top and bottom of the tailings sand, and the top and bottom electrode plates can be connected to a DC power supply;

[0016] S200, adding electrolyte solution to tailings sand;

[0017] S300, start the DC power supply and begin electroosmotic dehydration of tailings sand: during electroosmotic drainage, test the pH value of the solution in the tailings sand in real time (during the test, select a location far away from the cathode and anode electrode plates for testing), and adjust the positive and negative electrodes of the electrode plates of the dam body and the mountain body or the positive and negative electrodes of the electrode plates at the top and bottom of the tailings sand in real time according to the pH value of the solution of the tailings sand and the isoelectric point of the tailings sand, so that water flows out from the side close to the dam body when arranged left and right, or flows out from the bottom side of the tailings sand when arranged up and down.

[0018] Further, in S300, according to the pH of the tailings solution and the isoelectric point of the tailings, the method of adjusting the positive and negative electrodes of the electrode plates of the dam body and the mountain body or the positive and negative electrodes of the top and bottom electrode plates in real time is:

[0019] When the pH of the solution in the tailings is greater than the isoelectric point of the tailings, the electrode plate close to the mountain is connected to the positive electrode, and the electrode plate close to the dam is connected to the negative electrode; when the pH of the solution in the tailings is less than the isoelectric point of the tailings, the electrode plate close to the mountain is connected to the negative electrode, and the electrode plate close to the dam is connected to the positive electrode;

[0020] Or, when the pH of the solution in the tailings is greater than the isoelectric point of the tailings, the top electrode plate is connected to the positive electrode and the bottom electrode plate is connected to the negative electrode; when the pH of the solution in the tailings is less than the isoelectric point of the tailings, the top electrode plate is connected to the negative electrode and the bottom electrode plate is connected to the positive electrode.

[0021] Furthermore, the method further includes: S400, when the moisture content of the tailings sand decreases to a preset target value, turning off the DC power supply.

[0022] Furthermore, one end of the buried water pipe is connected to a water pump.

[0023] Furthermore, the electrode plate may be a titanium metal plate or other metal plates.

[0024] Furthermore, the electrolyte solution is any one of NaCl solution, KCl solution, NaOH solution and KOH solution.

[0025] The beneficial effects of this application are:

[0026] First, the basic concept of the present application is that the present invention accelerates the dehydration of tailings sand by passing a DC power supply into tailings sand with high water content, that is, due to the lattice substitution inside the colloid, the charge imbalance causes the solid surface to be charged, so that the net charge density per unit volume in the solution near the surface is not zero, thereby forming a compact layer and a diffusion layer. When an electric field is applied, the solution at a certain position within the diffusion layer away from the solid surface will undergo relative sliding.

[0027] 1.1, when arranged on the left and right, if it is acidic tailings, such as gold tailings, sulfide tailings, etc., its isoelectric point is pH = 2 ~ 4, and its electromotive potential decreases with the increase of pH. When the pH of the solution is greater than its isoelectric point, the surface of the acidic tailings particles is negatively charged, attracting H+ in the water, so that the aqueous solution carries a positive charge. Under the action of the electric field, the aqueous solution migrates to the cathode, so the cathode electrode is arranged close to the dam body, and the anode electrode is arranged far away from the dam body. When the pH of the solution is less than its isoelectric point, the electrode needs to be reversed (that is, the water flow does not necessarily move to the cathode);

[0028] 1.2, when arranged on the left and right, if it is alkaline tailings, such as carbonate mineral tailings, hydroxide mineral tailings, magnesite mineral tailings, etc., its isoelectric point is pH = 10 ~ 11, and its electromotive potential decreases with the increase of pH. When the solution pH is greater than its isoelectric point, the surface of the alkaline tailings particles is negatively charged, attracting H+ in the water, so that the aqueous solution carries a positive charge. Under the action of the electric field, the aqueous solution migrates to the cathode, so the cathode electrode is arranged close to the dam body, and the anode electrode is arranged far away from the dam body. When the solution pH is less than its isoelectric point, the electrode needs to be reversed;

[0029] 1.3, when arranged up and down, the cathode electrode and the anode electrode are arranged at the bottom and the top of the tailings sand respectively according to the same principle.

[0030] Second, arranging electrodes on the left and right allows the current to pass through the tailings sand layer more evenly, ensuring that the dehydration degree of each area of ​​the tailings sand is relatively consistent, thereby improving the overall dehydration effect. Arranging electrodes up and down helps to form an electric field gradient that is more conducive to the migration of water molecules, making it easier for water to converge and discharge, thereby accelerating the dehydration process, especially for tailings sand with high water content. Moreover, the structure of arranging electrodes on the left and right is relatively compact. For tailings sand treatment sites with limited site area, this arrangement can more effectively utilize vertical space and reduce site costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a cross-sectional schematic diagram of the first embodiment for realizing rapid dehydration of tailings sand by electroosmosis (electrodes are arranged on the left and right).

[0032] Figure 2 It is a cross-sectional schematic diagram of the second embodiment for realizing rapid dehydration of tailings sand by electroosmosis (electrodes are arranged up and down).

[0033] The following are the descriptions of the reference numerals:

[0034] 1—DC power supply;

[0035] 2—conductor;

[0036] 3—cathode electrode;

[0037] 4—dam body;

[0038] 5—water pump;

[0039] 6—Drain pipe;

[0040] 7.—Tailings;

[0041] 8—Mountain;

[0042] 9—Anode electrode. DETAILED DESCRIPTION

[0043] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0044] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0045] Embodiment 1

[0046] Figure 1 The electrode plate arrangement of the embodiment is shown. By properly arranging the electrode plates and applying an electric field, the dehydration speed of the tailings sand is accelerated. The specific implementation method of the tailings sand on-site is as follows:

[0047] S100, Preparation before Construction

[0048] S101, Site Preparation

[0049] Clean the tailings sand accumulation area to ensure that there are no large impurities and sharp objects to avoid damaging the electrode plate or affecting the electroosmosis effect. Dig drainage ditches around the tailings sand accumulation area. The bottom of the drainage ditch should be lower than the bottom of the tailings sand electroosmosis dehydration to form a certain water level difference, so that water can flow into the ditch naturally under the action of gravity. Its bottom should be about 30-50cm lower than the bottom of the tailings sand electroosmosis dehydration to ensure that the water in the tailings sand can be discharged in time during the construction process.

[0050] S102, Equipment and Material Preparation

[0051] According to the area and depth of the tailings, select the appropriate number, specifications and materials of electrode plates. Generally, the electrode plates are required to be corrosion-resistant, conductive and easy to install; prepare wires of sufficient length to ensure that the connection between the electrode plates and the power supply is stable and reliable. At the same time, select power supply equipment that can provide stable direct current. Set up drainage pipes near the cathode and equip them with pumps to extract the accumulated water.

[0052] S103, Tailings sand characteristics test

[0053] The tailings sand is tested for basic physical properties, such as particle size distribution, initial moisture content, etc. The particle size distribution of tailings sand affects its pore structure. If the tailings sand particles are fine and the pores are small, the ion migration path is relatively complex when voltage is applied. In order to ensure effective electroosmosis, the voltage may need to be appropriately reduced to prevent problems such as short circuits caused by excessive local electric field strength; tailings sand with high initial moisture content means that there are more conductive ions, and the current density will be relatively high at the same voltage. However, excessively high current density may cause problems such as electrode polarization, so it must be adjusted according to the moisture content. These parameters help determine the parameters of electroosmotic dehydration, such as voltage, current density, etc.

[0054] S200, electrode plate arrangement and wire connection

[0055] S201, electrode plate arrangement

[0056] According to the area and depth of the tailings, determine the layout of the electrode plates. This time, a symmetrical layout is adopted. Dig electrode trenches in the tailings, and the trench width should be slightly larger than the width of the electrode plate. At the same time, ensure that the spacing between the electrode trenches is reasonable. Generally speaking, the spacing between the electrode trenches should be determined according to the size of the electrode plate and the applied voltage. For example, when using smaller electrode plates (width of 20-30 cm) and lower voltage (1-2V / cm), the spacing between the electrode trenches can be set at about 30-50 cm, which can ensure that the electric field can effectively cover the tailings area and avoid the "dead zone" where the electric field strength is too low. Insert the electrode plate vertically into the electrode trench, and the insertion depth should ensure that most of the electrode plate is in good contact with the tailings, ensure that the electrode plate is in close contact with the tailings, and keep the electrode plates on the left and right sides parallel. At the same time, check whether the connection between the electrode plates is firm and reliable. Insulate the parts of the electrode plates that are in contact with the surrounding environment (such as the ground, equipment frame, etc.) to prevent current leakage. Insulating materials such as rubber and plastic can be used to wrap the non-working parts of the electrode plates.

[0057] S202, wire connection

[0058] Use insulated wires to connect the anode and cathode plates to the positive and negative poles of the power supply, respectively. During the connection process, ensure good contact between the wires and the electrode plates to avoid current loss caused by poor contact. After the connection is completed, use a current sensor to check whether the circuit is unobstructed. At the same time, ensure that the power supply device can work properly and provide stable DC power.

[0059] S300, electroosmotic dehydration operation

[0060] S301, start the power supply

[0061] According to the properties of the tailings and the dehydration requirements, set the output voltage and current of the power supply. Generally, the voltage is required to be stable and moderate to avoid damage to the electrode plate and tailings by excessively high or low voltage. After confirming that the circuit is unobstructed, add electrolyte solution to the tailings pond. The concentration and type of electrolyte solution are selected according to the specific composition and water content of the tailings. Then start the power supply equipment and gradually increase the voltage to the set value. At the same time, observe the changes in the readings of the current sensor to ensure that the current is stable and does not exceed the rated value.

[0062] S302, drainage treatment

[0063] Drainage pipes should be set up near the dam body and equipped with pumps to ensure that the accumulated water can be discharged in time. The drainage pipes should have a certain slope so that the water can flow out smoothly. When there is water accumulation in the drainage pipes, start the pumps to pump out the water. At the same time, observe the water flow in the drainage pipes to ensure smooth drainage.

[0064] S303, Monitoring and Adjustment

[0065] Regularly use conductivity meters and moisture meters to monitor the conductivity and water content of tailings. Evaluate the effect of electroosmotic dehydration by comparing monitoring data at different time points. According to the monitoring results, adjust the spacing or voltage of the electrode plates in time to optimize the electroosmotic dehydration effect. For example, when the electroosmotic speed is found to be slow, the voltage can be appropriately increased or the spacing between the electrode plates can be reduced; when the water content of the tailings is found to be too high, the electroosmotic time can be appropriately extended or the number of electrode plates can be increased.

[0066] S4010, power off

[0067] After dehydration is completed, turn off the DC power supply first, and then disconnect the electrode plate from the power supply. Carefully remove the electrode plate from the tailings sand and clean the tailings sand residue on the surface of the electrode plate. Check whether the electrode plate is damaged. If damaged, repair or replace it in time.

[0068] Embodiment 2

[0069] The difference between the second embodiment and the first embodiment is: S201, electrode plate arrangement.

[0070] S201 of the second embodiment includes: installation of upper and lower horizontal electrode plates: the electrode plates are placed flat on the bottom of the tailings to ensure that the electrode plates are in full contact with the tailings and the surface of the electrode plates is flat; the upper electrode plate is installed above the height of the tailings. The upper electrode plate is fixed by a bracket or a suspension device to ensure that it is placed horizontally and parallel to the bottom electrode plate. The spacing between the electrode plates is generally determined according to the properties of the tailings and tests.

[0071] It should be noted that, according to the pH of the tailings solution and the isoelectric point of the tailings, the positive and negative electrodes of the electrode plates of the dam body and the mountain body or the positive and negative electrodes of the electrode plates at the top and bottom are adjusted in real time ( Figure 1 , Figure 2 Just one of the situations is shown):

[0072] When the pH of the solution in the tailings is greater than the isoelectric point of the tailings, the electrode plate close to the mountain is connected to the positive electrode, and the electrode plate close to the dam is connected to the negative electrode; when the pH of the solution in the tailings is less than the isoelectric point of the tailings, the electrode plate close to the mountain is connected to the negative electrode, and the electrode plate close to the dam is connected to the positive electrode;

[0073] Or, when the pH of the solution in the tailings is greater than the isoelectric point of the tailings, the top electrode plate is connected to the positive electrode and the bottom electrode plate is connected to the negative electrode; when the pH of the solution in the tailings is less than the isoelectric point of the tailings, the top electrode plate is connected to the negative electrode and the bottom electrode plate is connected to the positive electrode.

[0074] The above embodiments are preferred implementation modes of the present invention and are only used to facilitate the description of the present invention. They are not intended to limit the present invention in any form. Any person with ordinary knowledge in the relevant technical field, if they do not depart from the scope of the technical features of the present invention, can make equivalent embodiments by partial changes or modifications to the technical contents disclosed in the present invention, and they still fall within the scope of the technical features of the present invention without departing from the technical features of the present invention.

Claims

1. A method for improving the stability of the tailings dam by electroosmosis-enhanced dehydration and consolidation of tailings sand, wherein the tailings sand is filled between the dam body and the mountain, and a buried water pipe is buried at the bottom of the tailings sand, characterized in that: It includes the following steps: S100, burying the electroosmosis dehydration system: left-right arrangement or top-bottom arrangement; The left and right arrangement is: a group of electrode plates are vertically arranged in the tailings sand near the dam body and the mountain body, and the electrode plates near the dam body and the mountain body can be connected to the DC power supply; The upper and lower arrangement is: a group of electrode plates are horizontally arranged at the top and bottom of the tailings sand, and the top and bottom electrode plates can be connected to a DC power supply; S200, adding electrolyte solution to tailings sand; S300, start the DC power supply and begin electroosmosis dehydration of tailings sand: during electroosmosis drainage, test the pH value of the solution in the tailings sand in real time, and adjust the positive and negative poles of the electrode plates of the dam body and the mountain body or the positive and negative poles of the electrode plates at the top and bottom in real time according to the pH value of the solution and the isoelectric point of the tailings sand, so that the water flows out from the side close to the dam body when arranged left and right, or flows out from the bottom side of the tailings sand when arranged up and down.

2. The method for improving the stability of the tailings dam by electroosmosis-enhanced dehydration and consolidation of tailings sand according to claim 1, characterized in that: In S300, according to the pH of the tailings solution and the isoelectric point of the tailings, the method of adjusting the positive and negative electrodes of the electrode plates of the dam body and the mountain body or the positive and negative electrodes of the top and bottom electrode plates in real time is: When the pH of the solution in the tailings is greater than the isoelectric point of the tailings, the electrode plate close to the mountain is connected to the positive electrode, and the electrode plate close to the dam is connected to the negative electrode; when the pH of the solution in the tailings is less than the isoelectric point of the tailings, the electrode plate close to the mountain is connected to the negative electrode, and the electrode plate close to the dam is connected to the positive electrode; Or, when the pH of the solution in the tailings is greater than the isoelectric point of the tailings, the top electrode plate is connected to the positive electrode and the bottom electrode plate is connected to the negative electrode; when the pH of the solution in the tailings is less than the isoelectric point of the tailings, the top electrode plate is connected to the negative electrode and the bottom electrode plate is connected to the positive electrode.

3. The method for improving the stability of the tailings dam by electroosmosis-enhanced dehydration and consolidation of tailings sand according to claim 1, characterized in that: Also includes: S400, when the moisture content of the tailings sand drops to the preset target value, the DC power supply is turned off.

4. The method for improving the stability of the tailings dam by electroosmosis-enhanced dehydration and consolidation of tailings sand according to claim 1, characterized in that: One end of the buried water pipe is connected with a water pump.

5. The method for improving the stability of the tailings dam by electroosmosis-enhanced dehydration and consolidation of tailings sand according to claim 1, characterized in that: The electrode plates can be titanium plates or other metal plates.

6. The method for improving the stability of the tailings dam by electroosmosis-enhanced dehydration and consolidation of tailings sand according to claim 1, characterized in that: The electrolyte solution is any one of NaCl solution, KCl solution, NaOH solution and KOH solution.

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