Cyanide-containing tailing harmless filling method and system

Abstract

According to the harmless filling method and system for the cyanide-containing tailings, cyanide-containing tailing slurry is directly subjected to filter pressing and dehydration, and rapid and efficient solid-liquid separation is achieved under the vacuum effect by adopting a ceramic filter press and utilizing a special microporous ceramic filter plate of the ceramic filter press. Furthermore, cyanide-containing wastewater is recycled and treated, and recycled water is used for washing and / or slurry preparation, so that the cyclic utilization of water resources is realized, the consumption of fresh water is reduced, and the production cost is reduced. By utilizing the belt conveyor with an accurate metering function, accurate control of the adding amount of the tailing filter cake is realized, and the consistency of the raw material proportion and the target value during subsequent stirring is ensured. Moreover, through automatic adjustment of online concentration monitoring and a central control system, real-time water supplementing adjustment can be achieved, it is ensured that the slurry concentration is always close to a set value, and therefore the uniformity and quality of filling materials are improved. In the filling process, the accuracy and the high efficiency of filling operation are ensured through the application of real-time monitoring and automatic control technologies.

Description

Technical Field

[0001] The present invention relates to the technical field of mine tailings disposal and resource utilization, and in particular to a harmless filling method and system for cyanide-containing tailings. Background Art

[0002] In the gold cyanide carbon-in-slurry (CIPS) process, large amounts of cyanide-containing tailings are typically produced to improve gold extraction rates. Due to the high toxicity of cyanide, if discharged without effective treatment, it can cause serious, long-term, and difficult-to-recover pollution to water, soil, and the environment. Therefore, mining companies must employ appropriate treatment processes to reduce the cyanide content in tailings to meet stringent environmental standards.

[0003] The traditional treatment process usually includes the following steps: the tailings slurry is first thickened by a thickener, and then the cyanide is broken and dehydrated, and finally the tailings are discharged to the tailings pond or used for filling underground goaf. However, this traditional process has the following disadvantages: First, the tailings pond storage method gradually reduces the cyanide concentration through natural degradation, oxidation and physical sealing, but it occupies a large area, has high construction and management costs, and there is a risk of leakage in long-term storage, which is easy to cause secondary environmental pollution. In addition, the tailings pond has safety hazards such as dam collapse, making it difficult to fully guarantee mine safety; second, the cyanide breaking chemical treatment method uses oxidants (such as sodium hypochlorite, chlorine dioxide, ozone, etc.) to oxidatively destroy or catalysts to assist in the oxidation and destruction of cyanide in the tailings slurry, converting it into harmless or low-toxic substances. Although this method has a certain treatment efficiency, it consumes a lot of chemical reagents, has high operating costs, and may introduce new pollutants. At the same time, it is greatly affected by the tailings slurry composition and reaction conditions, and the treatment stability is poor; third, the thickening and dehydration treatment method usually uses a deep cone thickener or The vertical sand bin thickener concentrates the tailings slurry, and then dehydrates it through a filter press or a belt filter press to reduce the moisture content of the tailings. However, the process is long, the equipment investment is large, and the maintenance cost is high. Flocculants usually need to be added during the thickening process, which increases operating costs and may have an adverse effect on the preparation of subsequent filling slurry. The moisture content of the dehydrated tailings is still high (usually 30%-40%), which is difficult to meet the requirements of subsequent filling or resource utilization; Fourthly, the filling method mixes the dehydrated tailings with cement and other gelling materials to make filling slurry, and transports it to the underground goaf for filling. However, this method has high requirements on the dehydration effect, slurry concentration and fluidity of the tailings slurry. The traditional process is prone to uneven filling slurry and insufficient strength due to the high moisture content of the tailings, which in turn affects the overall stability and support effect of the filling body.

[0004] In summary, existing technologies for treating cyanide-containing tailings suffer from complex processes, large equipment investments, high operating and maintenance costs, low treatment efficiency, difficulty in effectively reducing the moisture content of the tailings through thickening and dehydration, which affects subsequent filling results, high environmental risks, secondary pollution and safety hazards associated with cyanide destruction and tailings storage methods, low resource utilization, and insufficient recycling of tailings resources. Therefore, there is an urgent need for a solution that can simplify the process, reduce treatment costs, improve the dehydration efficiency of tailings slurry, ensure the environmental safety of tailings, and promote resource utilization. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention aims to provide a method and system for harmlessly filling cyanide-containing tailings.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for harmless filling of cyanide-containing tailings comprises the following steps:

[0008] Step 1: Filter pressing, dehydration and preliminary harmless treatment:

[0009] A corrosion-resistant high-density polyethylene pipeline is used to transport the cyanide-containing tailings slurry directly from the cyanide carbon slurry gold extraction workshop to a ceramic filter press. The ceramic filter press is equipped with a microporous ceramic filter plate and an alkali-resistant nylon filter cloth. The microporous ceramic filter plate is made of alumina ceramic filter plates. After the particle size distribution of the cyanide-containing tailings slurry is tested using a particle size analyzer, an alumina ceramic filter plate with a pore size 10%-30% smaller than the maximum particle size of the particles in the cyanide-containing tailings slurry is used to ensure a balance between filtration efficiency and tailings filter cake quality.

[0010] Under vacuum assistance, the cyanide-containing tailings slurry is separated into solid and liquid in a ceramic filter press, and the resulting tailings filter cake has a moisture content of 10%-15%. At the same time, the cyanide-containing wastewater produced by the filter press enters the harmless wastewater treatment module;

[0011] The harmless wastewater treatment module treats the cyanide-containing wastewater by one or more of pre-precipitation, redox reaction, and adsorption treatment, so that the residual cyanide content in the treated wastewater is reduced to the environmental protection standard. The treated wastewater is used as recycled water and enters step 2;

[0012] Step 2: Filter cake washing, metering and slurry preparation:

[0013] After the tailings filter cake obtained by the filter press in step 1 is evenly distributed in the ceramic filter press, the tailings filter cake is evenly rinsed with clean water or the recycled water obtained in step 1 to fully remove the residual cyanide-containing waste liquid on the tailings filter cake, ensure that the chemical composition of the tailings filter cake surface is stable, and do not damage the tailings filter cake structure;

[0014] Then, a belt conveyor with a built-in weighing unit is used to measure the weight of the tailings filter cake in real time, and the tailings filter cake with the set weight is conveyed to the mixing tank, while the remaining tailings filter cake is conveyed to the tailings pile for standby;

[0015] In the mixing tank, the concentration data of the tailings slurry in the mixing tank is monitored in real time by an online concentration monitor and transmitted to the central control system. The central control system controls the automatic water adding device to add the recycled water obtained in step 2 to the mixing tank according to the set concentration value, and dynamically adjusts the amount of water added. The stirrer is controlled to mix the tailings filter cake with water to form a tailings slurry, and the concentration of the obtained tailings slurry is accurately controlled at the set value to meet the filling requirements;

[0016] Step 3: Mixing and filling:

[0017] The tailings slurry obtained in step 2 is transported to a mixing bin under pressure through a pressure-resistant closed pipeline; a gelling material is added to the mixing bin, and the tailings slurry and the gelling material are fully mixed using a stirring device to generate a homogeneous filling slurry;

[0018] The obtained filling slurry is then transported to the underground goaf through a filling pipeline using a high-pressure plunger pump to fill the underground goaf.

[0019] Furthermore, in step 2, the spray pressure for flushing the tailings filter cake is set at 0.2 MPa to 0.5 MPa.

[0020] Furthermore, in step 2, the stirring speed of the stirrer is controlled between 200 and 300 rpm.

[0021] Furthermore, in step 2, the tailings filter cake is directly dropped onto a belt conveyor by using gravity or a vibration device.

[0022] Furthermore, in step 3, the pressure applied is 0.3 MPa to 0.6 MPa.

[0023] Furthermore, in step 3, the gelling material is cement, and the mass ratio of cement to filter cake weight is controlled between 1:6 and 1:10.

[0024] Furthermore, in step 3, the working pressure of the high-pressure plunger pump is 2MPa to 5MPa.

[0025] Furthermore, the central control system monitors the motor current, voltage, temperature and vibration parameters of the high-pressure plunger pump, agitator and stirring device, and immediately shuts down and issues an alarm when an abnormality occurs. The central control system accurately controls the amount of cementitious material added through the metering feeding system.

[0026] Furthermore, in step 3, pressure, flow and concentration monitoring devices are installed at multiple locations of the filling pipeline and the underground goaf. The pressure, flow and concentration monitoring devices transmit the monitored data to the central control system. The central control system monitors the pressure, flow and concentration of the filling slurry in the filling pipeline and the underground goaf in real time to ensure the safety of the filling process.

[0027] Secondly, an ultrasonic blockage detector is installed at the easily blocked part of the filling pipe. The central control system monitors whether the filling pipe is blocked through the ultrasonic blockage detector and starts the backwash program when blockage is detected.

[0028] The central control system is equipped with an emergency stop button and a backup power supply system.

[0029] The present invention also provides a system for implementing the above method, comprising a corrosion-resistant HDPE pipeline, a ceramic filter press, a harmless wastewater treatment module, a belt conveyor with a built-in weighing and metering unit, a stirring tank, a central control system, an online concentration monitor, an automatic water adding device, an agitator, a pressure-resistant and sealed pipeline, a stirring chamber, and a high-pressure plunger pump;

[0030] The corrosion-resistant HDPE pipeline is connected to the cyanide carbon slurry gold extraction workshop and the ceramic filter press respectively; the ceramic filter press is equipped with a microporous ceramic filter plate and an alkali-resistant nylon filter cloth for filtering the cyanide-containing tailings slurry;

[0031] The harmless wastewater treatment module is used to treat the cyanide-containing wastewater obtained by pressure filtration using one or more of pre-precipitation, redox reaction and adsorption treatment, so as to reduce the residual cyanide content in the wastewater obtained after treatment to the environmental protection standard requirement;

[0032] The belt conveyor with a built-in weighing and metering unit is used to perform real-time weight detection on the tailings filter cake obtained by filter pressing, and to convey the tailings filter cake of a set weight to the stirring tank, while the remaining tailings filter cake is conveyed to the tailings pile for standby use;

[0033] The stirring tank is used to mix the tailings filter cake with water to form tailings slurry;

[0034] The online concentration monitor is used to monitor the concentration data of the tailings slurry in the stirring tank in real time and transmit it to the central control system. The central control system is used to control the automatic water adding device to dynamically adjust the amount of water added according to the set concentration value, and control the agitator to mix the filter cake with water to form a tailings slurry;

[0035] The pressure-resistant and sealed pipes are respectively connected to the stirring tank and the stirring chamber;

[0036] The mixing bin is used to fully mix the tailings slurry and the gelling material to generate a homogeneous filling slurry;

[0037] The high-pressure plunger pump is used to transport the obtained filling slurry to the underground goaf through the filling pipeline to fill the underground goaf.

[0038] The beneficial effects of the present invention are:

[0039] 1. This invention directly dewaters the cyanide-containing tailings slurry by filter pressing, omitting the traditional thickening step and effectively simplifying the process. By using a ceramic filter press and its unique microporous ceramic filter plates, rapid and efficient solid-liquid separation is achieved under vacuum, significantly improving dehydration efficiency and reducing the moisture content of the tailings.

[0040] 2. Compared with the traditional deep cone thickening process, the direct filter pressing dehydration method adopted by the present invention has significant advantages. In terms of equipment investment, the expensive deep cone thickener and its supporting equipment, such as the thickener drive device, rake lifting device, etc., are eliminated, which greatly reduces the equipment procurement cost. In terms of operating costs, the energy consumption of the ceramic filter press is relatively low. Its vacuum system mainly consumes electricity and has a relatively low power. In comparison, the operation of the deep cone thickener requires a large amount of electricity to drive the rotation and stirring of the thickener, as well as to maintain the flocculant addition system during the thickening process. In terms of dehydration efficiency, the ceramic filter press can reduce the moisture content of the tailings to a lower level in a shorter period of time. The moisture content of the tailings after treatment with the traditional deep cone thickening process is generally 30%-40%, while the present invention can reduce the moisture content of the tailings to 10%-15%, providing better material conditions for subsequent processes and improving the overall process efficiency.

[0041] 3. The present invention recycles and treats cyanide-containing wastewater, and uses the recycled water for flushing and / or slurry preparation, thereby realizing the recycling of water resources, reducing the consumption of fresh water, and lowering production costs.

[0042] 4. The present invention utilizes a belt conveyor with precise metering function to achieve accurate control of the amount of tailings filter cake added, ensuring that the raw material ratio is consistent with the target value during subsequent stirring, and avoiding slurry concentration fluctuations due to metering errors.

[0043] 5. In the present invention, through online concentration monitoring and automatic adjustment of the central control system, water replenishment and adjustment can be made in real time to ensure that the slurry concentration is always maintained at the set value, thereby improving the uniformity and quality of the filling material.

[0044] 6. The present invention directly performs high-pressure washing on the filter plate of the ceramic filter press, and then uses gravity or a vibration device to make the filter cake fall off onto a belt conveyor, eliminating the tedious manual processing or multi-stage conveying process.

[0045] 7. The present invention can flexibly adjust the concentration of the filling slurry, so that the filling slurry can form a more stable filling body after solidification underground, effectively support the surrounding rock of the goaf, and reduce the risk of geological disasters such as ground collapse.

[0046] 8. During the filling process, the application of real-time monitoring and automatic control technology in the present invention ensures the accuracy and efficiency of the filling operation, avoids filling quality problems caused by uneven filling or unstable pressure, improves the filling effect, shortens the construction time, and improves the mining operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a flowchart of the implementation of the method of Example 1 of the present invention;

[0048] Figure 2 This is a structural diagram of the system of Example 2 of the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment.

[0050] Example 1

[0051] This embodiment provides a method for harmless filling of cyanide-containing tailings, such as Figure 1 As shown, the following steps are included:

[0052] Step 1: Direct filter pressing and dehydration:

[0053] (1) Tailings slurry transportation: Use corrosion-resistant HDPE pipeline to transport cyanide-containing tailings slurry directly from the cyanide carbon slurry gold extraction workshop to the ceramic filter press;

[0054] (2) Filter Press Dehydration: The ceramic filter press is equipped with a microporous ceramic filter plate and an alkali-resistant nylon filter cloth. The microporous ceramic filter plate is an alumina ceramic filter plate.

[0055] First, after testing the particle size distribution of the cyanide-containing tailings slurry using a particle size analyzer, an alumina ceramic filter plate with a pore size 10%-30% smaller than the maximum particle size of the particles in the cyanide-containing tailings slurry is selected to ensure a balance between filtration efficiency and filter cake quality.

[0056] The vacuum degree is set between -0.05MPa and -0.08MPa, and the moisture content of the tailings filter cake is monitored in real time. When the data is close to 15%, the filtration time is automatically extended or the vacuum degree is adjusted to keep the moisture content of the tailings filter cake stably controlled at 10%.

[0057] (3) Wastewater recovery and harmless treatment: The cyanide-containing wastewater generated by filtration is sent to the filtrate treatment tank and monitored in real time by a liquid level sensor. Once the liquid level in the filtrate treatment tank reaches the set value, the automatic wastewater recovery system starts immediately to collect the cyanide-containing wastewater and send it to the harmless wastewater treatment module.

[0058] The harmless wastewater treatment module adopts dual physical and chemical treatment. First, the cyanide-containing wastewater is pre-precipitated to remove larger particles of suspended solids in the cyanide-containing wastewater; then, cyanide is decomposed through redox reaction; and adsorption treatment is used to further remove residual harmful substances to ensure that the residual cyanide in the wastewater is reduced to environmental protection standards. The treated wastewater is used as recycled water in step 2, effectively reducing the consumption of fresh water and realizing efficient use of water resources.

[0059] Step 2: Filter cake transfer and slurry preparation:

[0060] (1) Flushing treatment: After the tailings filter cake forms a certain thickness on the filter plate of the filter press, it is evenly flushed by spraying water (clean water or recycled water obtained in step 1) at a pressure of 0.2 MPa to ensure the adequacy of the flushing and without damaging the tailings filter cake structure;

[0061] (2) Filter cake transportation and metering: The tailings filter cake after washing is automatically detached from the filter plate by a vibration device and gravity assistance. The tailings filter cake of set weight is transported to the mixing tank by a belt conveyor with a built-in weighing and metering unit. The excess tailings filter cake is transported to the tailings pile as a backup.

[0062] (3) Water addition and concentration control: An online concentration monitor is installed in the mixing tank to feed back the slurry concentration data to the central control system in real time. At the same time, an automatic water addition valve is installed in the mixing tank. The central control system controls the automatic water addition valve switch based on the data fed back by the online concentration monitor, thereby dynamically adjusting the water addition flow rate to ensure that the slurry concentration is stably set at 70% to meet the filling requirements.

[0063] The tailings filter cake and water were uniformly mixed in the stirring tank by an agitator (200 rpm) for 5 minutes to ensure that all the tailings filter cake and water were fully mixed while preventing excessive stirring from causing degradation of slurry performance. The water used in this example was the recycled water obtained in step 1.

[0064] Step 3: Mixing and filling in the well:

[0065] (1) Preparation of filling slurry: The tailings slurry is transported to the mixing bin at a pressure of 0.3 MPa in a pressure-resistant closed pipeline, and cement is added to the mixing bin as a gelling material.

[0066] In this embodiment, cement is added from the cement silo to the mixing silo via a metering feeding system and a screw conveyor according to a cement to tailings filter cake weight ratio of 1:6.

[0067] In the mixing chamber, the materials are mixed evenly by a twin-shaft mixer at a speed of 150 rpm for 5 minutes to form a filling slurry. The filling slurry is temporarily stored in a hopper.

[0068] (2) Filling operation: The filling slurry is transported to the goaf in the underground mining area through the filling pipeline by a high-pressure plunger pump (working pressure of 5MPa) to form a filling body, and the filling retaining wall construction is completed before the filling operation. Multiple pressure, flow and concentration monitoring devices are installed in the filling pipeline and goaf. The pressure, flow and concentration monitoring devices upload the monitored pressure, flow and concentration data to the central control system. When the filling area reaches the designed height, the filling stops automatically, completing a filling cycle.

[0069] In this embodiment, the central control system monitors the motor current, voltage, temperature, and vibration parameters of the high-pressure plunger pump, agitator, and stirring device. If an abnormality is detected, the system will immediately shut down and issue an alarm. Furthermore, ultrasonic blockage detectors are installed at locations prone to blockage in the filling pipe. The central control system uses these ultrasonic blockage detectors to monitor for blockage in the filling pipe and initiates a backwashing procedure if a blockage is detected. Furthermore, the central control system is equipped with an emergency stop button and a backup power supply system.

[0070] Example 2

[0071] This embodiment provides a system for implementing the method described in embodiment 1, such as Figure 2 As shown, it includes corrosion-resistant HDPE pipelines, a ceramic filter press 1, a harmless wastewater treatment module 4, a belt conveyor 2 with a built-in weighing and metering unit, a stirring tank 3, a central control system, an online concentration monitor, an automatic water adding device, an agitator, a pressure-resistant and sealed pipeline, a stirring chamber 5 and a high-pressure plunger pump 6.

[0072] The corrosion-resistant HDPE pipeline is connected to the cyanide carbon slurry gold extraction workshop and the ceramic filter press 1 respectively; the ceramic filter press 1 is equipped with a microporous ceramic filter plate and an alkali-resistant nylon filter cloth for filtering the cyanide-containing tailings slurry;

[0073] The harmless wastewater treatment module 4 is used to treat the cyanide-containing wastewater obtained by pressure filtration using one or more of pre-precipitation, redox reaction, and adsorption treatment methods, thereby reducing the residual cyanide content in the treated wastewater to environmental standards. In this embodiment, a filtrate treatment tank 7 is also included. The cyanide-containing wastewater obtained by pressure filtration is temporarily stored in the filtrate treatment tank 7. When the liquid level in the filtrate treatment tank 7 reaches a set value, an automatic wastewater recovery system automatically collects the cyanide-containing wastewater and transfers it to the harmless wastewater treatment module 4 for treatment.

[0074] The belt conveyor 2 with a built-in weighing and metering unit is used to perform real-time weight detection on the tailings filter cake obtained by filter pressing, and to convey the tailings filter cake of a set weight to the stirring tank 3, and the remaining tailings filter cake is conveyed to the tailings pile 8 for standby use;

[0075] The stirring tank 3 is used to mix the filter cake with water to form tailings slurry;

[0076] The online concentration monitor is used to monitor the concentration data of the tailings slurry in the stirring tank 3 in real time and transmit it to the central control system. The central control system is used to control the automatic water adding device to dynamically adjust the amount of water added according to the set concentration value, and control the agitator to mix the filter cake with water to form a tailings slurry;

[0077] The pressure-resistant sealed pipe 9 is connected to the stirring tank 3 and the stirring chamber 5 respectively;

[0078] The mixing bin 5 is used to thoroughly mix the tailings slurry and the cementitious material to produce a homogeneous filling slurry. In this embodiment, the mixing bin 5 comprises a twin-shaft mixer. The cementitious material is fed into the mixing bin via a cement bin 14, a metering feeder 15, and a screw conveyor 16.

[0079] The high-pressure plunger pump 6 is used to transport the resulting filling slurry through the filling pipeline 10 to the underground goaf 12 of the stope 11, filling the underground goaf 12 to form a filling body 13. In this embodiment, the resulting filling slurry is temporarily stored in a hopper 17 and then transported from the hopper 17 to the underground goaf 12. The construction of the filling retaining wall 18 is completed before the filling operation.

[0080] Those skilled in the art can make various corresponding changes and modifications based on the above technical solutions and concepts, and all of these changes and modifications should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for harmless filling of cyanide-containing tailings, characterized in that: The steps include: Step 1: Filter pressing, dehydration and preliminary harmless treatment: A corrosion-resistant high-density polyethylene pipeline is used to transport the cyanide-containing tailings slurry directly from the cyanide carbon slurry gold extraction workshop to a ceramic filter press. The ceramic filter press is equipped with a microporous ceramic filter plate and an alkali-resistant nylon filter cloth. The microporous ceramic filter plate is made of alumina ceramic filter plates. After the particle size distribution of the cyanide-containing tailings slurry is tested using a particle size analyzer, an alumina ceramic filter plate with a pore size 10%-30% smaller than the maximum particle size of the particles in the cyanide-containing tailings slurry is used to ensure a balance between filtration efficiency and filter cake quality. Under vacuum assistance, the cyanide-containing tailings slurry is separated into solid and liquid in a ceramic filter press, and the resulting tailings filter cake has a moisture content of 10%-15%. At the same time, the cyanide-containing wastewater produced by the filter press enters the harmless wastewater treatment module; The harmless wastewater treatment module treats the cyanide-containing wastewater by one or more of pre-precipitation, redox reaction, and adsorption treatment, so that the residual cyanide content in the treated wastewater is reduced to the environmental protection standard. The treated wastewater is used as recycled water and enters step 2; Step 2: Filter cake washing, metering and slurry preparation: After the tailings filter cake obtained by the filter press in step 1 is evenly distributed in the ceramic filter press, the tailings filter cake is evenly rinsed with clean water or the recycled water obtained in step 1 to fully remove the residual cyanide-containing waste liquid on the tailings filter cake, ensure that the chemical composition of the tailings filter cake surface is stable, and do not damage the tailings filter cake structure; Then, a belt conveyor with a built-in weighing unit is used to measure the weight of the tailings filter cake in real time, and the tailings filter cake with the set weight is conveyed to the mixing tank, while the remaining tailings filter cake is conveyed to the tailings pile for standby; In the mixing tank, the concentration data of the tailings slurry in the mixing tank is monitored in real time by an online concentration monitor and transmitted to the central control system. The central control system controls the automatic water adding device to add the recycled water obtained in step 2 to the mixing tank according to the set concentration value, and dynamically adjusts the amount of water added. The stirrer is controlled to mix the tailings filter cake with water to form a tailings slurry, and the concentration of the obtained tailings slurry is accurately controlled at the set value to meet the filling requirements; Step 3: Mixing and filling: The tailings slurry obtained in step 2 is transported to a mixing bin under pressure through a pressure-resistant closed pipeline; a gelling material is added to the mixing bin, and the tailings slurry and the gelling material are fully mixed using a stirring device to generate a homogeneous filling slurry; The obtained filling slurry is then transported to the underground goaf through a filling pipeline using a high-pressure plunger pump to fill the underground goaf.

2. The method according to claim 1, characterized in that In step 2, the spray pressure for washing the tailings filter cake is set at 0.2 MPa to 0.5 MPa.

3. The method according to claim 1, characterized in that In step 2, the stirring speed of the stirrer is controlled between 200 and 300 rpm.

4. The method according to claim 1, wherein In step 2, the tailings filter cake is directly dropped onto a belt conveyor using gravity or a vibrating device.

5. The method according to claim 1, wherein In step 3, the pressure applied is 0.3 MPa to 0.6 MPa.

6. The method according to claim 1, characterized in that In step 3, the gelling material is cement, and the mass ratio of cement to filter cake weight is controlled between 1:6 and 1:

10.

7. The method according to claim 1, characterized in that In step 3, the working pressure of the high-pressure plunger pump is 2MPa to 5MPa.

8. The method according to claim 1, characterized in that The central control system monitors the motor current, voltage, temperature and vibration parameters of the high-pressure plunger pump, agitator and stirring device. In case of abnormality, the system will immediately shut down and issue an alarm. The central control system accurately controls the amount of cementitious material added through the metering feeding system.

9. The method according to claim 1, characterized in that In step 3, pressure, flow and concentration monitoring devices are installed at multiple locations in the filling pipeline and the underground goaf. The pressure, flow and concentration monitoring devices transmit the monitored data to the central control system. The central control system monitors the pressure, flow and concentration of the filling slurry in the filling pipeline and the underground goaf in real time to ensure the safety of the filling process. Secondly, an ultrasonic blockage detector is installed at the easily blocked part of the filling pipe. The central control system monitors whether the filling pipe is blocked through the ultrasonic blockage detector and starts the backwash program when blockage is detected. The central control system is equipped with an emergency stop button and a backup power supply system.

10. A system for implementing the method of any one of claims 1 to 9, comprising a corrosion-resistant HDPE pipeline, a ceramic filter press, a harmless wastewater treatment module, a belt conveyor with a built-in weighing and metering unit, a stirring tank, a central control system, an online concentration monitor, an automatic water adding device, an agitator, a pressure-resistant sealed pipeline, a stirring chamber, and a high-pressure plunger pump; The corrosion-resistant HDPE pipeline is connected to the cyanide carbon slurry gold extraction workshop and the ceramic filter press respectively; the ceramic filter press is equipped with a microporous ceramic filter plate and an alkali-resistant nylon filter cloth for filtering the cyanide-containing tailings slurry; The harmless wastewater treatment module is used to treat the cyanide-containing wastewater obtained by pressure filtration using one or more of pre-precipitation, redox reaction and adsorption treatment, so as to reduce the residual cyanide content in the wastewater obtained after treatment to the environmental protection standard requirement; The belt conveyor with a built-in weighing and metering unit is used to perform real-time weight detection on the tailings filter cake obtained by filter pressing, and to convey the tailings filter cake of a set weight to the stirring tank, while the remaining tailings filter cake is conveyed to the tailings pile for standby use; The stirring tank is used to mix the tailings filter cake with water to form tailings slurry; The online concentration monitor is used to monitor the concentration data of the tailings slurry in the stirring tank in real time and transmit it to the central control system. The central control system is used to control the automatic water adding device to dynamically adjust the amount of water added according to the set concentration value, and control the agitator to mix the filter cake with water to form a tailings slurry; The pressure-resistant and sealed pipes are respectively connected to the stirring tank and the stirring chamber; The mixing bin is used to fully mix the tailings slurry and the gelling material to generate a homogeneous filling slurry; The high-pressure plunger pump is used to transport the obtained filling slurry to the underground goaf through the filling pipeline to fill the underground goaf.

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