A method for controlling the underflow concentration of a deep-cone thickener for metal mine filling

Abstract

The application designs a kind of deep cone thickener underflow concentration control method for metal mine filling, and relates to the field of metal mine filling engineering;Torque, ultrasonic velocity, mud layer height and underflow flow are controlled in turn to prevent rake pressing accidents and give early warning of concentration deviation state;And for the mutual interference that may occur in the four control processes, the corresponding weights of the four control processes are given;Efficient and stable control of underflow concentration, early warning of concentration deviation state, each control system works cooperatively and does not interfere with each other;The application is designed based on the actual situation, solves the problems of heavy workload of existing deep cone thickener, frequent rake pressing accidents and time-consuming problems in handling rake pressing accidents by pre-evacuating thickening tank.

Description

Technical Field

[0001] This invention relates to the field of metal mine backfilling engineering, and in particular to a method for controlling the underflow concentration of a deep cone thickener used for metal mine backfilling. Background Technology

[0002] All mineral resources of a certain grade require mineral processing to increase their content in order to meet the needs of subsequent metallurgical processes. This process inevitably produces a large amount of mineral processing waste, known as tailings. In the past, tailings were stored in surface tailings ponds, which posed a serious challenge to the environmental protection concept of "green mountains and clear waters".

[0003] Backfilling is the reverse process of mining. The main process involves thickening tailings slurry by adding different types of cementing materials, commonly cement. After mixing, the slurry is pumped or gravity-fed to deep mined-out areas to form a solidified backfill of a certain strength. This solidified backfill then works with the surrounding rock to stabilize ground pressure. To ensure backfilling efficiency and quality, deep cone thickeners are typically used to thicken the tailings slurry, simultaneously improving settling efficiency and concentration. Thickeners are widely used in mineral processing, wastewater treatment, and other engineering fields requiring solid-liquid separation. To meet the requirements of the backfilling process, deep cone-shaped metal ore backfilling thickeners are often designed. However, stable control of the underflow concentration is crucial. If the concentration is below the design standard, the resulting backfill will have low strength, which is detrimental to safe underground mining. If the concentration is above the design standard, it increases the high-torque workload on the bottom climbing frame of the deep cone thickener, potentially leading to interruption of the thickening process.

[0004] Therefore, it is necessary to start with a collaborative control strategy, monitor the underflow state of the deep cone thickener and the workload of the motor drive system, use multiple state parameters as input parameters for the control strategy, establish a model for stable concentration collaborative control, and adopt multiple output control parameters to achieve the goal of stable underflow concentration control, provide early warning when the concentration deviates from the set value, and achieve the goal of continuous operation and stable control of underflow concentration.

[0005] Existing deep cone thickeners are prone to rake-over accidents due to their heavy workload. Dealing with rake-over accidents requires emptying the thickener tank beforehand, which generally takes 48 hours, followed by 36 hours of manual cleaning, which seriously affects the operation of the machine. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention proposes a method for controlling the underflow concentration of a deep cone thickener used for metal mine backfilling. The method optimizes the torque control system, ultrasonic speed control system, mud layer height control system, and underflow flow rate control system. Specifically, torque sensors and ultrasonic concentration meters are used to directly and indirectly monitor the underflow concentration status to prevent rake accidents and provide early warnings of concentration deviations. Simultaneously, the various control systems work collaboratively without interfering with each other.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for controlling the underflow concentration of a deep cone thickener used for backfilling metal mines includes the following:

[0009] The thickener is based on the existing mining thickener, but the conventional nozzle is replaced with a rotary nozzle;

[0010] First, the ultrasonic concentration meter is monitored by a PLC to obtain the underflow concentration of the thickener; it is then determined whether the underflow concentration exceeds the set concentration threshold. If so, the speed of the underflow variable frequency pump is increased by the frequency converter, thereby increasing the delivery capacity of the thickener underflow pump and increasing the discharge volume of the slurry; the underflow variable frequency pump is driven by the output signal of the PID controller.

[0011] The PLC receives the continuous torque signal from the thickener detected by the torque sensor and determines whether the torque signal exceeds the set torque threshold. If so, it turns on the water pump to inject water to dilute the slurry. Specifically, turning on the water pump to inject water to dilute the slurry involves controlling the water injection volume by monitoring the underflow concentration of the thickener using an ultrasonic concentration meter until the underflow concentration is normal, and then turning off the water pump.

[0012] The PLC determines whether the motor load exceeds a set load threshold, which is set to 5% of the upper limit of the motor load. If so, an alarm is automatically triggered, and the height of the rake frame is controlled to adjust the motor load. If the underflow concentration decreases, the load decreases, and the rake frame will automatically lower. If the load continues to increase, the rake frame will continue to rise until it reaches the highest point and the thickener stops working. During the lifting process, it is determined whether the rake frame has reached the set warning height. If so, the water pump is turned on to inject water to flush away the mud. The water injection volume is adjusted according to the monitored underflow concentration until the underflow concentration is normal, and then the water pump is turned off.

[0013] Before the rake frame is raised to the warning height, corrective measures are taken in advance. When the rake alarm device on the side of the geared motor automatically generates an audible alarm and the control panel displays a "danger" yellow light signal, the PLC controller detects the analog signal from the torque sensor and automatically turns on the water pump after logical judgment. The water pump receives the "distress" signal and injects water into the slurry through the low-speed rotating high-pressure nozzle to flush it away. The detected underflow concentration is compared with the pre-given concentration value to obtain the deviation change. After internal PID calculation, the frequency converter output frequency is adjusted to change the speed of the water pump motor until the concentration monitored by the ultrasonic concentration meter drops to the normal range. At this point, the high-pressure nozzle stops injecting water, and the thickener control system returns to steady state.

[0014] If the water pump motor speed is too high, causing an increase in the water volume inside the thickener, and the ultrasonic velocity detected by the ultrasonic concentration meter is too slow, resulting in a slurry concentration significantly lower than the specified lower limit, then gradually reduce the speed of the underflow pump to decrease the slurry output. If the ultrasonic velocity detected by the ultrasonic concentration meter is still lower than the set value, use a control pulse metering pump to increase the amount of flocculant added until the underflow concentration changes from thin to thick and the ultrasonic velocity tends to return to normal, ending the underflow concentration deviation. Keep the speed of the underflow pump constant and restore the amount of flocculant added to the normal value. The control panel displays a green "safe" light, indicating that the thickener control system is in a steady state.

[0015] When the feed and discharge rates of the deep cone thickener are constant, the height of the solid-liquid interface determines the underflow concentration. If the mud layer height increases, it will lead to an increase in underflow concentration and rake torque. The height of the phase interface is detected by a mud layer height gauge to control the underflow concentration. The density of the deep cone thickener is detected before the underflow slurry is discharged. Underflow is only discharged when the design density is reached. The density is detected at the outlet pipe of the underflow pump. Underflow that does not reach the design density value is automatically circulated back to the thickener for further concentration until the design density value is reached.

[0016] When the above control processes work simultaneously and interfere with each other, the weight of the control system's role in each of the above control processes is as follows: torque control, ultrasonic speed control, mud layer height control, and bottom flow rate control, to ensure the coordinated and stable operation of each control process; PID composite control is adopted, introducing composite control variables; torque control is the main control, with other controls as auxiliary controls; under the same control conditions, torque control has the highest priority, and the output signal of the torque sensor is used as the control target;

[0017] During the operation of the thickener system, if the material inside the thickener reacts too slowly and is mixed unevenly, resulting in the appearance of solid lumps of mud in some areas, the mud level gauge will default to the mud level reaching the set requirement and output a "false signal" that the underflow concentration is too low and more reagent needs to be added. At this time, the torque motor speed is the primary control quantity, and measures such as increasing the underflow slurry discharge or injecting water through the high-pressure nozzle should be taken in time until the torque motor speed meets the set value, at which point the thickener system will reset and return to a steady state.

[0018] When the torque is running normally, the remaining control process is mainly based on ultrasonic speed. If the ultrasonic speed is detected to be too low, but the mud height gauge detects that the mud height meets the set value, flocculant still needs to be added according to the ratio. In mud height control and underflow flow control, mud height control takes priority over underflow flow control. The underflow flow control system plays an auxiliary role in the underflow concentration control strategy of this invention.

[0019] Finally, through real-time analysis and control, fault data and operation data monitored during the on-site filling and commissioning process are obtained, and a troubleshooting database is established on this basis. An artificial neural network is built using Matlab software to learn and predict the rake pressing process, so that the control system can react in advance when the concentration of the thickener underflow is too high.

[0020] The artificial neural network model is based on sound wave velocity, motor torque and concentration. It uses an ultrasonic concentration meter and torque sensor as input signals to adjust the rake. The concentration is used as the output variable of the artificial neural network. The artificial neural network model is updated by the preset dropout parameter value to obtain the optimal rake frame speed setting value.

[0021] The artificial neural network model employs a programmable logic array, including programmable input / output units, configurable logic blocks, a digital clock management module, embedded block RAM, wiring resources, embedded dedicated hard cores, and low-level embedded functional units. The neural network prediction process is written into the FPGA to solve the problems of slow response and large lag characteristics of the deep cone thickener from large sample data, thereby achieving high efficiency and stability of the thickener control system.

[0022] Beneficial technical effects of the present invention:

[0023] This invention provides a method for controlling the underflow concentration of a deep cone thickener used for backfilling metal mines. The method consists of four parts: torque control, ultrasonic speed control, mud layer height control, and underflow flow rate control. It also provides the priority levels of these four control processes under two different working conditions. The method provided by this invention can efficiently and stably control the underflow concentration, prevent rake accidents, provide early warning of concentration deviations, and ensure that the various control processes work together without interfering with each other. Attached Figure Description

[0024] Figure 1 Two-dimensional cross-sectional view of a deep cone thickener according to an embodiment of the present invention;

[0025] Figure 2 Concentration control diagram of thickener underflow in an embodiment of the present invention;

[0026] Figure 3 Flowchart of the thickener underflow concentration control method according to an embodiment of the present invention;

[0027] Figure 4 Flowchart of the thickener underflow concentration control method according to an embodiment of the present invention;

[0028] Figure 5 A diagram illustrating the three-stage hydraulic protection system for thickener underflow concentration control in this invention.

[0029] Among them, 1-deep cone thickener, 2-drive system, 3-torque sensor, 4-raw material injection port, 5-sludge height gauge, 6-feed well, 7-diffuser plate, 8-overflow port, 9-overflow pre-filter, 10-compression zone, 11-rake frame, 12-high pressure rotary nozzle, 13-branch pipe, 14-discharge port, 15-underflow variable frequency pump, 16-ultrasonic concentration meter, 17-gate valve, 18-slurry flow meter, 19-controller. Detailed Implementation

[0030] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0031] A method for controlling the underflow concentration of a deep cone thickener used for backfilling metal mines includes the following:

[0032] The thickener is based on the existing mining thickener, with the conventional nozzle replaced by a rotary nozzle 12; as shown in the attached figure. Figure 1 As shown;

[0033] This invention employs multi-channel PID (Proportion Integration Differentiation) control, as shown in the attached figure. Figure 2 As shown, torque control, ultrasonic speed control, mud layer height control, and underflow flow control are achieved through a PLC controller, and analog signals are received from torque sensor 3, ultrasonic concentration meter 16, mud layer height 5, slurry flow meter 18, etc. A three-stage hydraulic protection system is adopted. First, the torque and underflow concentration of the deep cone thickener 1 are adjusted to prevent the underflow concentration from increasing and losing fluidity, and to prevent the rake accident caused by excessive torque. Second, the underflow discharge concentration and flow rate of the deep cone thickener 1 are stabilized to ensure the stability of the filling system.

[0034] The drive system 2 includes a motor, reducer, and speed encoder. In the feed well 6, tailings and flocculant are thoroughly mixed to form flocculent inclusions, which settle evenly and reduce the resistance torque of the central rake in the deep cone thickener. The geared motor mainly drives the main shaft components of the thickener. An alarm is installed on one side of the geared motor. A dynamic torque sensor 3 is connected to the main shaft via a coupling. The sensor can directly collect the driving torque data of the main shaft, and the driving torque data indicates the mud concentration and the force required for the rake to move in the mud. A mud level gauge 5 is installed at the top of the thickener. In actual operation of the deep cone thickener 1, the sand level is generally controlled at 8-9m, ensuring the amount of tailings used in each filling while effectively preventing excessive material buildup or prolonged storage time in the deep cone thickener 1. An ultrasonic concentration meter 16 and a slurry flow meter 18 are located in the underflow slurry pipeline, with the slurry flow meter 18 located after the ultrasonic concentration meter 16.

[0035] The bottom of the rake frame 11 of the deep cone thickener 1 is connected to the branch pipe 13, and the high-pressure nozzles 12 are evenly installed on the branch pipe 13. There are multiple high-pressure nozzles 12. The high-pressure nozzles 12 rotate synchronously with the deep cone thickener 1 at low speed in the cone, which can homogenize and fluidize the slurry that is about to solidify, and there are no dead corners. When the underflow concentration at the bottom of the cone of the deep cone thickener 1 is too high, high-pressure water is injected by a clean water pump through the high-pressure nozzles 12 to gradually restore the torque to a steady state.

[0036] The underflow concentration control strategy of the deep cone thickener 1 adopts a three-level protection hydraulic system, as shown in the attached figure. Figure 5 As shown; the purpose is to protect expensive equipment components.

[0037] The slurry with a low concentration of about 10% to 20% by mass is transported through pipeline to the raw material inlet 4 of the deep cone thickener 1, and flocculant is added at the same time. The rake of the deep cone thickener 1 moves in a regular circular motion.

[0038] During the thickening process, solid particles, under the influence of gravity, enter the feed cylinder and continuously settle, diffusing outwards through the diffuser plate 7 into the deep cone thickener 1. After filtration by the overflow pre-filter 9, the clarified liquid flows out through the overflow port 8 of the deep cone thickener 1 and is used as circulating water. The slurry entering the compression zone 10 is first detected by the mud level gauge 5 at the top left of the deep cone thickener 1. If the mud level tends to be too high, the internal PID channel 3 calculates and adjusts the inverter output frequency to control the underflow concentration by controlling the phase interface height. If the mud level is too low at this time, it is necessary to wait for the slurry to settle before discharging it through the discharge port 14.

[0039] The deep cone thickener 1 uses a torque sensor 3 in the drive system 2 to detect the torque of the rake, as shown in the attached diagram. Figure 3 As shown; simultaneously, the ultrasonic concentration meter 16 located in the bottom pipe of the deep cone thickener 1 collects the ultrasonic velocity. If the ultrasonic velocity is slightly higher or lower than the set velocity value, the error is adjusted through the internal PID channel 2 to drive the frequency converter to change the speed of the water pump motor. The high-pressure nozzle 12 injects water into the slurry until the ultrasonic velocity in the compression zone 10 detected by the ultrasonic concentration meter 16 approaches the given value, at which point the water pump valve is closed. If the ultrasonic concentration meter 16 detects that the ultrasonic velocity is too fast, the underflow concentration is too high, resulting in a significant increase in torque. The PID controller directly drives the underflow frequency converter pump 15 to increase the slurry discharge.

[0040] If the concentration is still too high, the motor power of the deep cone thickener 1 will continue to increase to 5% of the set load limit. When the rake frame 11 is overloaded (the operating pressure is set to 5MPa, and the main drive working pressure of the deep cone thickener 1 reaches this value as an overload), the rake frame 11 will be raised to a certain height (the height position is adjustable). The rake frame will continue to operate at this height. If the load decreases (below 5MPa), the rake frame 11 will automatically lower. If the load continues to increase at this height, the rake frame 11 will be raised and tested until it reaches the highest point.

[0041] Before the rake frame 11 reaches its highest point, the control system takes corrective measures. When the detection device detects that the torque output of the drive unit exceeds 50% of the maximum operating torque, the rake alarm device on the side of the geared motor will automatically generate an audible alarm signal, and the control panel will simultaneously display a yellow "Danger" warning light. Upon receiving the rake-pressing signal, the high-pressure nozzle 12 quickly flushes away the mud from around the bottom of the deep cone thickener 1. Through internal PID channel 2 calculations, the inverter output frequency is adjusted to increase the speed of the water pump motor until the control panel displays a green light, indicating that the "rake-pressing danger" has been eliminated, and the high-pressure nozzle 12 automatically shuts off. When the detection device detects that the torque output of the drive unit exceeds 95% of the maximum operating torque, the motor stops, and the rake frame 11 stops accordingly. When the maximum operating torque is reached (100%), the hydraulic pressure opens the relief valve, bypassing the hydraulic system.

[0042] If too much water was injected into the mud nozzle in the previous step, as shown in the attached image... Figure 4 As shown, when the underflow concentration detected by the ultrasonic concentration meter 16 is lower than the set value, it is necessary to increase the amount of flocculant added by controlling the pulse metering pump until the underflow concentration changes from thin to thick and the sound wave velocity tends to normal. Then, keep the speed of the underflow variable frequency pump 15 unchanged and restore the amount of flocculant added to the normal value.

[0043] The slurry flow meter 18, through internal PID channel 4 calculation, adjusts the output frequency of the frequency converter, and controls the discharge volume of the underflow slurry by changing the speed of the underflow frequency pump 15, thereby maintaining the stability of the underflow concentration of the thickener.

[0044] When the above control processes operate simultaneously and interfere with each other, PID composite control is adopted to further ensure the coordinated and stable operation of each control system, introducing composite control variables. The specific control strategy includes the following steps:

[0045] Step S1: Torque control is the primary focus, with other controls playing a secondary role. Under the same control conditions, torque control has the highest priority, and the output signal of torque sensor 3 is used as the primary control target.

[0046] Step S2: When the torque is running normally, the other control systems mainly use PID channel 2 ultrasonic speed control. The system detects that the ultrasonic speed is too low, but the mud height gauge 5 detects that the mud height meets the set value. At this time, flocculant still needs to be added according to the ratio.

[0047] Step S3: In the mud layer height control system and the underflow flow control system, the control of mud layer height takes priority over the control of underflow flow. The underflow flow control system plays an auxiliary role in the underflow concentration control strategy of this invention.

[0048] The priority order of the sensors is as follows: torque sensor 3 > ultrasonic concentration meter 16 > mud layer height meter 5 ≥ slurry flow meter 18.

[0049] Ultimately, under the control of the entire system, the underflow concentration supplied to the next process from the thickener is stabilized between 60% and 70%, and the system can ensure that the underflow concentration is controlled within ±1.5% of the concentration required by the customer.

[0050] Specifically, in the above technical solution, the underflow conveying pipeline of the deep cone thickener 1 is equipped with a three-way conversion valve, which can switch the underflow conveying direction at any time. When filling is required, the slurry is pumped to the mixer of the paste mixing system through the underflow pump of the deep cone thickener 1; when filling is not required, the slurry is flowed by gravity or pumped to the tailings dam through the underflow of the deep cone thickener 1 for storage; some slurry with insufficient concentration due to insufficient reaction with flocculant is discharged to the emergency pool by gravity.

[0051] In addition, the main unit of the deep cone thickener 1 is equipped with a PLC and control panel. The control panel can be used to set and read various parameters, and can also be used to observe the position of the thickener rake frame 11 and fault alarm status.

Claims

1. A method for controlling the underflow concentration of a deep cone thickener used for backfilling metal ore, characterized in that, Includes the following: First, the ultrasonic concentration meter is monitored by a PLC to obtain the underflow concentration of the thickener; it is then determined whether the underflow concentration exceeds the set concentration threshold. If so, the speed of the underflow variable frequency pump is increased by the frequency converter, thereby increasing the delivery capacity of the thickener underflow pump and increasing the discharge volume of the slurry; the underflow variable frequency pump is driven by the output signal of the PID controller. The PLC receives the continuous torque signal from the thickener detected by the torque sensor and determines whether the torque signal exceeds the set torque threshold; if so, it turns on the water pump to inject water to dilute the slurry. The PLC determines whether the motor load exceeds a set load threshold, which is set to 5% of the upper limit of the motor load. If so, an alarm is automatically triggered, and the height of the rake frame is controlled to adjust the motor load. If the underflow concentration decreases, the load decreases, and the rake frame will automatically lower. If the load continues to increase, the rake frame will continue to rise until it reaches the highest point and the thickener stops working. During the lifting process, it is determined whether the rake frame has reached the set warning height. If so, the water pump is turned on to inject water to flush away the mud. The water injection volume is adjusted according to the monitored underflow concentration until the underflow concentration is normal, and then the water pump is turned off. If the water pump motor speed is too high, causing an increase in the water volume inside the thickener, and the ultrasonic velocity detected by the ultrasonic concentration meter is too slow, resulting in a slurry concentration significantly lower than the specified lower limit, then gradually reduce the speed of the underflow pump to decrease the slurry output. If the ultrasonic velocity detected by the ultrasonic concentration meter is still lower than the set value, use a control pulse metering pump to increase the amount of flocculant added until the underflow concentration changes from thin to thick and the ultrasonic velocity tends to normal, ending the underflow concentration deviation. Keep the speed of the underflow pump constant and restore the amount of flocculant added to the normal value. The control panel displays a green "safe" light, indicating that the thickener control system is in a steady state. When the feed and discharge rates of the deep cone thickener are constant, the height of the solid-liquid interface determines the underflow concentration. If the mud layer height increases, it will lead to an increase in underflow concentration and rake torque. The height of the phase interface is detected by a mud layer height gauge to control the underflow concentration. The density of the deep cone thickener is detected before the underflow slurry is discharged. Underflow is only discharged when the design density is reached. The density is detected at the outlet pipe of the underflow pump. Underflow that does not reach the design density value is automatically circulated back to the thickener for further concentration until the design density value is reached. When the above control processes work simultaneously and interfere with each other, the weight of the control system's role in each of the above control processes is as follows: torque control, ultrasonic speed control, mud layer height control, and bottom flow rate control, to ensure the coordinated and stable operation of each control process; PID composite control is adopted, introducing composite control variables; torque control is the main control, with other controls as auxiliary controls; under the same control conditions, torque control has the highest priority, and the output signal of the torque sensor is used as the control target; During the operation of the thickener system, if the material inside the thickener reacts too slowly and is mixed unevenly, resulting in the appearance of solid lumps of mud in some areas, the mud level gauge will default to the mud level reaching the set requirement and output a "false signal" that the underflow concentration is too low and more reagent needs to be added. At this time, the torque motor speed is the primary control quantity, and measures such as increasing the underflow slurry discharge or injecting water through the high-pressure nozzle should be taken in time until the torque motor speed meets the set value, at which point the thickener system will reset and return to a steady state. When the torque is running normally, the rest of the control process is mainly based on ultrasonic speed. If the ultrasonic speed is detected to be too low, but the mud height gauge detects that the mud height meets the set value, flocculant still needs to be added according to the ratio. In mud height control and underflow flow control, mud height control takes priority over underflow flow control. The underflow flow control system plays an auxiliary role in the underflow concentration control strategy. Finally, through real-time analysis and control, fault data and operation data monitored during the on-site filling and commissioning process are obtained, and a troubleshooting database is established on this basis. An artificial neural network is built using Matlab software to learn and predict the rake pressing process, so that the control system can react in advance when the concentration of the thickener underflow is too high. The artificial neural network model is based on sound wave velocity, motor torque, and concentration. It uses an ultrasonic concentration meter and torque sensor as input signals to adjust the rake. The concentration is used as the output variable of the artificial neural network. The artificial neural network model is updated by a preset dropout parameter value to obtain the optimal rake frame speed setting value.

2. The method for controlling the underflow concentration of a deep cone thickener for metal ore backfilling according to claim 1, characterized in that, The thickener is based on the existing mining thickener, but the conventional nozzle is replaced with a rotary nozzle.

3. The method for controlling the underflow concentration of a deep cone thickener for metal ore backfilling according to claim 1, characterized in that, The process of turning on the water pump to inject water to dilute the slurry involves controlling the water injection volume by monitoring the underflow concentration of the thickener using an ultrasonic concentration meter until the underflow concentration is normal, at which point the water pump is turned off.

4. The method for controlling the underflow concentration of a deep cone thickener for metal ore backfilling according to claim 1, characterized in that, Before the rake frame is raised to the warning height, corrective measures are taken in advance. When the rake alarm device on the side of the geared motor automatically generates an audible alarm and the control panel displays a "danger" yellow light signal, the PLC controller detects the analog signal from the torque sensor and automatically turns on the water pump after logical judgment. The water pump receives the "distress" signal and injects water into the slurry through the low-speed rotating high-pressure nozzle to flush it away. The detected underflow concentration is compared with the pre-given concentration value to obtain the deviation change. After internal PID calculation, the frequency converter output frequency is adjusted to change the speed of the water pump motor until the concentration monitored by the ultrasonic concentration meter drops to the normal range. At this point, the high-pressure nozzle stops injecting water, and the thickener control system returns to steady state.

5. The method for controlling the underflow concentration of a deep cone thickener for metal ore backfilling according to claim 1, characterized in that, The artificial neural network model employs a programmable logic array, including programmable input / output units, configurable logic blocks, a digital clock management module, embedded block RAM, wiring resources, embedded dedicated hard cores, and low-level embedded functional units. The neural network prediction process is written into the FPGA to solve the problems of slow response and large lag characteristics of the deep cone thickener from large sample data, thereby achieving high efficiency and stability of the thickener control system.

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