Flotation equipment for beneficiation metallurgy wastewater and working method thereof

Abstract

The invention relates to the technical field of beneficiation and metallurgy wastewater treatment, in particular to flotation equipment for beneficiation and metallurgy wastewater and a working method thereof, and the flotation equipment comprises a flotation tank body, a microbubble generation module, a self-adaptive agent adding unit, a foam recognition and scraping mechanism, a liquid level linkage control assembly and a water quality feedback adjusting system. According to the equipment, stable microbubbles are generated through the microporous ceramic tube, and the mineralization efficiency is improved by combining an atomized medicament; and accurate foam scraping is achieved through visual recognition and PLC control, and drug adding and gas supply parameters are dynamically adjusted based on multi-parameter feedback of turbidity, pH and ORP. According to the invention, the trapping efficiency of fine particle pollutants in high-viscosity, high-ionic-strength and oil-containing colloidal metallurgical wastewater can be effectively improved, the energy consumption is reduced, and the stability of the effluent quality is ensured.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of mineral processing and metallurgy and water treatment, specifically a flotation device for mineral processing and metallurgical wastewater and its working method. Background Technology

[0002] With the continuous development of the mineral processing and metallurgical industry, flotation technology, as a key means of mineral separation and resource recovery, has been widely applied in various ores and metal recovery processes. However, in actual production, the direct discharge of large amounts of mineral processing and metallurgical wastewater containing heavy metals, suspended solids, and organic pollutants without effective treatment will cause serious harm to the ecological environment. Therefore, developing efficient flotation equipment and its supporting operating methods specifically for mineral processing and metallurgical wastewater has become an important research direction in the field of environmental protection and comprehensive resource utilization. Existing flotation equipment is mostly designed for raw ore pulp or specific metal particles, making it difficult to effectively adapt to metallurgical wastewater systems with complex composition, high viscosity, and high levels of surface-active substances. It suffers from problems such as poor bubble stability, low reagent utilization, low froth layer removal efficiency, and insufficient automation control capabilities.

[0003] A search revealed a jet atomization flotation device with publication number CN111570100B, published on May 25, 2021. This patent achieves efficient mixing of the frother with the slurry through a jet atomization device, utilizing jet energy to enhance microbubble stability and promote mineralization efficiency between mineral particles and bubbles. However, this technical solution is primarily geared towards traditional slurry flotation scenarios, failing to consider the interference of high-concentration ions, oils, or colloidal substances in metallurgical wastewater on bubble interfacial tension and reagent adsorption performance, and lacking an adaptive control mechanism for wastewater characteristics. Furthermore, its structure relies on a circulating pump to provide jet kinetic energy, resulting in high energy consumption, and it lacks integrated online monitoring or feedback adjustment functions for residual pollutants after wastewater flotation, making it difficult to meet the stability and intelligent control requirements of metallurgical wastewater treatment.

[0004] A search revealed a mineral flotation device and its flotation process, with publication number CN114832953B, published on July 21, 2023. This patent uses a method of directly sucking up the foam layer through an air pipe to reduce slurry entrainment and incorporates internal cleaning nozzles to maintain equipment cleanliness. While this design improves the purity of foam collection and ease of equipment maintenance to some extent, its core focus remains on concentrate recovery during ore flotation, without optimizing for the capture of low-concentration target substances (such as trace heavy metal complexes or fine suspended solids) in metallurgical wastewater. Furthermore, its bubble generation method is relatively traditional, lacking the ability to actively control the distribution of microbubble size. Since the flotation effect of metallurgical wastewater highly depends on the uniformity and stability of microbubbles, this solution may suffer from low flotation efficiency, high reagent consumption, and substandard effluent quality when treating such wastewater.

[0005] The aforementioned problems indicate that existing flotation equipment generally suffers from technical bottlenecks when treating mineral processing and metallurgical wastewater, including insufficient applicability, low bubble control precision, lack of intelligent feedback mechanisms, and weak adaptability to complex water qualities. Therefore, this invention provides a flotation device and its operating method for mineral processing and metallurgical wastewater. The aim is to significantly improve the removal efficiency and operational stability of pollutants in metallurgical wastewater by optimizing the bubble generation system, introducing an adaptive adjustment strategy for wastewater characteristics, integrating an intelligent foam layer identification and precise scraping mechanism, and combining reagent dosing and liquid level linkage control. This meets the dual requirements of modern green metallurgy and environmental compliance. Summary of the Invention

[0006] The present invention addresses the problem of providing a flotation device and its operating method for mineral processing and metallurgical wastewater. It solves the technical problems of existing flotation equipment when treating metallurgical wastewater with complex composition, high viscosity, high concentrations of ions, oils, and colloidal substances. These problems include poor bubble stability, uncontrollable microbubble size distribution, low contact efficiency between reagents and pollutants, insufficient precision in foam layer removal, and lack of responsiveness to changes in water quality. Furthermore, traditional flotation devices often rely on circulating pumps to provide jet kinetic energy, resulting in high energy consumption. They also lack integrated real-time sensing and adjustment mechanisms for flotation performance, leading to low collection efficiency, large fluctuations in effluent quality, and poor operational continuity when treating low-concentration heavy metal complexes or fine suspended solids.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a flotation device for mineral processing and metallurgical wastewater, comprising a flotation tank, a microbubble generating module, an adaptive reagent dosing unit, a foam identification and scraping mechanism, a liquid level linkage control component, and a water quality feedback adjustment system. The flotation tank is a rectangular closed structure with an inlet at the bottom and an overflow weir at the top. The microbubble generating module is installed on the inner side of the bottom of the flotation tank and includes several microporous ceramic tubes arranged in parallel. The microporous ceramic tubes are fixed to the bottom plate of the flotation tank by flanges. One end of each microporous ceramic tube is connected to a compressed air source through a gas distribution chamber, and the other end is closed. The adaptive reagent dosing unit includes a reagent storage tank, a metering pump, and a multi-point injection pipeline. The multi-point injection pipeline is arranged 200mm above the microporous ceramic tubes along the length of the flotation tank. Multiple atomizing nozzles are spaced apart on the multi-point injection pipeline, and the atomizing nozzles are installed at a 30° angle towards the outlet of the microporous ceramic tubes. The foam identification and scraping mechanism is installed in a rectangular closed structure with an inlet at the bottom and an overflow weir at the top. The microbubble generating module is installed on the inner side of the bottom of the flotation tank. The microbubble generating module includes several microporous ceramic tubes arranged in parallel. The microbubble generating module includes several microporous ceramic tubes arranged in a rectangular closed structure with an inlet at the bottom and an overflow weir at the top. The microbubble generating module is installed on the inner side of the flotation tank ... The scraping mechanism includes a scraper bracket spanning the top of the flotation tank, a servo motor, a scraper arm, and a visual recognition camera. The scraper bracket is mounted on both sides of the flotation tank via bearing seats. The output shaft of the servo motor is connected to one end of the scraper bracket via a coupling. The scraper arm is vertically welded to the bottom of the scraper bracket. The visual recognition camera is fixed above one side of the flotation tank via an L-shaped bracket, with the lens facing the overflow weir area. The liquid level linkage control component includes an ultrasonic level gauge, an electric regulating valve, and a PLC controller. The ultrasonic level gauge is installed in the middle of the inner side wall of the flotation tank. The electric regulating valve is connected in series to the inlet pipe. The PLC controller is electrically connected to the ultrasonic level gauge, the electric regulating valve, the metering pump, and the servo motor. The water quality feedback adjustment system includes an online turbidity sensor, a pH electrode, and an ORP probe. The online turbidity sensor, pH electrode, and ORP probe are all installed on the inner wall of the flotation tank outlet via threaded interfaces and are signal-connected to the PLC controller.

[0008] Preferably, the microporous ceramic tube has a pore size range of 10–50 μm, a porosity of not less than 40%, a tube wall thickness of 5 mm, and each microporous ceramic tube is coated with a hydrophobic polytetrafluoroethylene film layer with a thickness of 0.2 mm. The gas distribution chamber is provided with a pressure stabilizing plate, and the pressure stabilizing plate has a honeycomb-shaped through-hole array with a pore size of 2 mm and a pore spacing of 5 mm.

[0009] Preferably, the multi-point injection pipeline is made of 316L stainless steel with an inner diameter of 15mm. The atomizing nozzle has a swirling structure with a nozzle diameter of 0.8mm and an injection angle of 60°. Each atomizing nozzle is equipped with a one-way check valve at its rear end to prevent wastewater backflow.

[0010] Preferably, a flexible silicone scraper is installed at the lower end of the scraper arm. The flexible silicone scraper is embedded in the groove on the bottom surface of the scraper arm through a snap-fit ​​structure. The bottom of the scraper is flush with the top surface of the overflow weir. Guide vanes are provided on both sides of the scraper arm. The angle between the guide vanes and the horizontal plane is 15°, which is used to guide the foam to concentrate towards the overflow weir.

[0011] Preferably, the visual recognition camera is an industrial-grade CMOS image sensor with a resolution of 1920×1080, a frame rate of 30fps, a lens focal length of 12mm, and is equipped with an infrared fill light. The PLC controller has a pre-stored foam grayscale threshold model. When the proportion of white area in the image captured by the camera exceeds the set threshold, the servo motor is triggered to start the scraper action.

[0012] Preferably, the online turbidity sensor has a measurement range of 0–1000 NTU and a response time of 2 seconds; the pH electrode is a glass composite electrode with a measurement range of 0–14; and the ORP probe uses a platinum sensing head with a measurement range of -1000 to +1000 mV. The signals from the three sensors are converted from analog to digital and then input to the PLC controller for multi-parameter fusion analysis.

[0013] Preferably, the PLC controller dynamically adjusts the start-stop frequency and flow rate of the metering pump based on real-time data of turbidity, pH, and ORP. When the turbidity is higher than 80 NTU and the ORP is lower than -200 mV, the PLC controller increases the flow rate of the metering pump by 15%. When the pH deviates from the range of 6.5–8.5, the PLC controller synchronously adjusts the reagent type switching valve to switch to the acidic or alkaline regulator branch.

[0014] A working method for a flotation device for mineral processing and metallurgical wastewater, comprising the following specific steps: Step 1: Metallurgical wastewater enters the flotation tank through the inlet. An ultrasonic level gauge monitors the liquid level in the tank in real time. When the liquid level is lower than the set value, the PLC controller outputs a signal to open the electric regulating valve to increase the inlet flow rate and maintain the liquid level at 50mm below the overflow weir. Step 2: Compressed air enters the microporous ceramic tube after being pressurized by the gas distribution chamber. It forms a uniform microbubble cluster with a diameter of 20–80μm through the hydrophobic polytetrafluoroethylene film layer. During the bubble rise, it is fully mixed with the atomized reagent sprayed from the multi-point injection pipeline. The reagent droplet size is controlled at 10–30μm. Step 1: The mineralized bubbles collide with microbubbles to form mineralized bubbles. Step 2: The mineralized bubbles carry pollutants to the surface and form a foam layer. The visual recognition camera continuously collects images of the overflow weir area. The PLC controller performs grayscale analysis on the images. When the foam coverage area exceeds 70%, the servo motor is started to drive the scraper support to rotate. The flexible silicone scraper pushes the foam into the overflow weir collection tank. During the scraping process, the guide vanes inhibit slurry entrainment. Step 3: The online turbidity sensor, pH electrode and ORP probe collect effluent water quality data every 10 seconds. The PLC controller dynamically adjusts the dosage and type of reagents according to the multi-parameter fusion results. If the turbidity decrease rate is less than 0.5 NTU / s for three consecutive tests, the air supply pressure of the microporous ceramic tube is automatically increased by 0.05 MPa to increase the bubble generation density. Step 4: After the flotation process is completed, the PLC controller shuts off the metering pump and compressed air source, opens the bottom drain valve to drain the residual sludge, and starts the high-pressure flushing pump to perform reverse pulse cleaning on the microporous ceramic tube. The cleaning cycle is 5 minutes after each run, and the pulse frequency is 1Hz to continuously remove membrane pore blockage.

[0015] The beneficial effects of this invention are: stable microbubbles are generated through microporous ceramic tubes, which, combined with atomized reagents, enhances mineralization efficiency; precise foam removal is achieved using visual recognition and PLC control; and reagent dosing and gas supply parameters are dynamically adjusted based on multi-parameter feedback of turbidity, pH, and ORP. This application can effectively improve the collection efficiency of fine particulate pollutants in high-viscosity, high-ionic-strength, and oily colloidal metallurgical wastewater, reduce energy consumption, and ensure stable effluent quality. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the flotation equipment for mineral processing and metallurgical wastewater according to the present invention. Figure 2 This is a schematic diagram of the front view cross-section of the flotation equipment for mineral processing and metallurgical wastewater according to the present invention. Figure 3 This is a schematic diagram of the internal three-dimensional structure of the flotation equipment for mineral processing and metallurgical wastewater according to the present invention. Figure 4 This is a bottom-view three-dimensional structural diagram of the flotation equipment for mineral processing and metallurgical wastewater according to the present invention.

[0017] The attached diagram is labeled as follows: 1. Flotation tank; 2. Microporous ceramic tube; 3. Gas distribution chamber; 4. Compressed air source; 5. Reagent storage tank; 6. Metering pump; 7. Multi-point injection pipeline; 8. Atomizing nozzle; 9. Scraper support; 10. Servo motor; 11. Scraper arm; 12. Visual recognition camera; 13. Overflow weir; 14. Ultrasonic level gauge; 15. Electric regulating valve; 16. PLC controller; 17. Online turbidity sensor; 18. pH electrode; 19. ORP probe; 20. Flexible silicone scraper; 21. Guide vane; 22. Inlet. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Specific implementation examples are given below.

[0020] This invention provides a flotation device and its working method for mineral processing and metallurgical wastewater, the specific implementation of which is described below; Figure 1 As shown, the entire flotation equipment consists of a flotation tank 1 as its main structure. The flotation tank 1 is a rectangular closed steel structure container with an internal volume of 8m³ and dimensions of 4000mm × 2000mm × 1500mm (length × width × height). An inlet 22 is located at the center of the bottom of the flotation tank 1 to introduce the metallurgical wastewater to be treated. An overflow weir 13, 1200mm high, is located on one side of the top along the length direction to collect the foam layer formed after flotation and guide it to an external foam collection tank. Inside the flotation tank 1, from bottom to top, are arranged a microbubble generating module, an adaptive reagent dosing unit, and a foam recognition and scraping mechanism. The entire process is automatically controlled through a liquid level linkage control component and a water quality feedback adjustment system. The microbubble generating module includes several microporous ceramic tubes 2 arranged in parallel on the bottom plate of the flotation cell 1. Each microporous ceramic tube 2 is 1800 mm long, 30 mm in outer diameter, 20 mm in inner diameter, 5 mm thick, with a pore size range of 10–50 μm and a porosity of not less than 40%. One end of each microporous ceramic tube 2 is sealed and fixed to the bottom plate of the flotation cell 1 by a flange, while the other end is closed to prevent liquid backflow. The air inlet ends of all microporous ceramic tubes 2 are connected to the same gas distribution chamber 3. The gas distribution chamber 3 is a stainless steel welded box with a pressure stabilizing plate inside. The plate has a honeycomb-shaped array of through holes, each with a diameter of 2 mm and a spacing of 5 mm, which is used to equalize the compressed air pressure entering each microporous ceramic tube 2. The gas distribution chamber 3 is connected to an external compressed air source 4 through a pipe. The outlet of the compressed air source 4 is equipped with a pressure reducing valve and a flow meter, which can stabilize the supply pressure in the range of 0.2–0.4 MPa. In addition, each microporous ceramic tube 2 is coated with a layer of polytetrafluoroethylene hydrophobic film with a thickness of 0.2 mm. This film is tightly attached to the outer wall of the ceramic tube by heat shrinking process to enhance the efficiency of bubble detachment and prevent contaminants from clogging the micropores. The adaptive reagent dosing unit is located 200mm directly above the microporous ceramic tube 2, and includes a reagent storage tank 5, a metering pump 6, and a multi-point injection pipeline 7. The reagent storage tank 5 is a vertical PE tank with a volume of 200L, equipped with an internal stirrer to maintain reagent uniformity. The metering pump 6 is a diaphragm metering pump with a maximum flow rate of 10L / min and an outlet pressure of 0.6MPa. Its inlet is connected to the bottom of the reagent storage tank 5 via a flexible hose, and its outlet is connected to the multi-point injection pipeline 7 via a rigid PVC pipe. The multi-point injection pipeline 7 is made of 316L stainless steel with an inner diameter of 15mm, and extends along the length of the flotation tank 1. The reagents are arranged horizontally and fixed to the inner wall of the flotation cell 1 at both ends by brackets. Atomizing nozzles 8 are installed every 300 mm on the multi-point injection pipeline 7, for a total of 13 atomizing nozzles 8. Each atomizing nozzle 8 has a swirling structure with a nozzle diameter of 0.8 mm and an injection angle of 60°. Its axis is installed at a 30° inclination towards the outlet of the microporous ceramic tube 2, so that the reagent spray can directly cover the rising path of the microbubbles. Each atomizing nozzle 8 has a one-way check valve at its rear end. The check valve has a spring-loaded structure and an opening pressure of 0.05 MPa, which can effectively prevent wastewater in the flotation cell 1 from flowing back into the reagent pipeline when the pump is stopped. The foam recognition and scraping mechanism spans the top of the flotation tank 1 and includes a scraper support 9, a servo motor 10, a scraper arm 11, and a vision recognition camera 12. The scraper support 9 is a welded rectangular steel pipe structure, slightly longer than the width of the flotation tank 1. Both ends are mounted on support platforms on the outer walls of the flotation tank 1 via rolling bearing seats to ensure smooth rotation. The servo motor 10 is fixed to one side of the outer wall of the flotation tank 1, and its output shaft is coaxially connected to one end of the scraper support 9 via a flexible coupling, which can drive the scraper support 9 to rotate slowly around a horizontal axis. The scraper arm 11 is a bent stainless steel plate component, vertically welded below the scraper support 9, with two sets symmetrically distributed on both sides of the scraper support 9. The lower end of the scraper arm 11 has a groove, in which a flexible silicone scraper strip 20 is embedded via a snap-fit ​​structure. The scraper strip 20 is 50 μm wide. The scraper arm 11 has a thickness of 8mm and its bottom edge is flush with the top surface of the overflow weir 13, ensuring that the scraping action accurately contacts the foam layer without disturbing the liquid phase below. Guide vanes 21 are welded to both sides of the scraper arm 11. The guide vanes 21 are curved stainless steel plates with an angle of 15° to the horizontal plane, and their front ends point towards the center of the overflow weir 13, used to guide the foam towards the overflow weir 13 during the scraping process. The visual recognition camera 12 is an industrial-grade CMOS image sensor with a resolution of 1920×1080, a frame rate of 30fps, and a lens focal length of 12mm. It is fixed above one side of the flotation tank 1 by an L-shaped bracket, with the lens optical axis facing the overflow weir 13 area, and is equipped with an infrared supplementary light to adapt to low-light conditions. The camera 12 is connected to the PLC controller 16 via a shielded cable to transmit image data in real time. The liquid level linkage control component includes an ultrasonic level gauge 14, an electric regulating valve 15, and a PLC controller 16. The ultrasonic level gauge 14 is installed in the middle of the inner side wall of the flotation tank 1, 750mm from the bottom plate. Its probe emits ultrasonic signals downwards, with a measurement range of 0–1500mm and an accuracy of ±2mm. The electric regulating valve 15 is a pneumatic diaphragm regulating valve with a nominal diameter of DN100, installed in series on the upstream pipe of the inlet 22. Its actuator is connected to the solenoid valve through an air supply line. The PLC controller 16 is a Siemens S7. The -1200 series programmable logic controller (PLC) is installed in the equipment's electrical control cabinet. Its digital input module receives the 4–20mA analog signal from the ultrasonic level gauge 14, and after internal program judgment, outputs a 4–20mA control signal to the positioner of the electric regulating valve 15 to achieve closed-loop regulation of the inlet water flow. When the liquid level is lower than the set value (usually 50mm below the overflow weir 13, i.e., 1150mm in height), the PLC controller 16 increases the opening of the electric regulating valve 15; when the liquid level is higher than the set value, it decreases the opening to maintain a stable liquid level. The water quality feedback and adjustment system includes an online turbidity sensor 17, a pH electrode 18, and an ORP probe 19. All three are installed on the inner wall of the flotation tank 1 at the outlet end via a standard threaded interface (G1 / 2″), located 1000mm above the bottom plate, in the mainstream area to ensure sample representativeness. The online turbidity sensor 17 uses a 90° scattered light principle, with a measurement range of 0–1000 NTU and a response time of 2 seconds. The pH electrode 18 is a glass composite electrode with a built-in Ag / AgCl reference system, with a measurement range of 0–14. The ORP probe 19 uses a platinum sensing head with an Ag / AgCl reference electrode, with a measurement range of -1000 to +1000 mV. The output signals of all three are connected to the analog input module of the PLC controller 16 via shielded cables, and after analog-to-digital conversion, multi-parameter fusion analysis is performed. The PLC controller 16 has a preset control logic: when the turbidity is higher than 80 NTU and the ORP is lower than -200 NTU... When the pH value is mV, it is determined that the pollutant load is high and there are many reducing substances, and the operating frequency of metering pump 6 is automatically increased by 15%. When the pH value is lower than 6.5 or higher than 8.5, PLC controller 16 outputs a switch signal to the three-way switching valve (not shown in the figure) at the outlet of reagent storage tank 5, switching to the acidic regulator (such as dilute sulfuric acid) or alkaline regulator (such as sodium hydroxide solution) branch to achieve pH adaptive adjustment. The operation of this equipment is performed as follows: First, metallurgical wastewater enters the inlet 22 through a pipeline. The ultrasonic level gauge 14 monitors the liquid level in the flotation tank 1 in real time and transmits the signal to the PLC controller 16. The PLC controller 16 calculates the deviation according to the set value (1150mm) and outputs a control signal to adjust the opening of the electric regulating valve 15, so that the liquid level is stabilized at 50mm below the overflow weir 13. Then, the compressed air source 4 is started. The compressed air enters the gas distribution chamber 3 after being depressurized, and is distributed to each microporous ceramic tube 2 after being evenly pressurized by the pressure stabilizing plate. Under the action of the polytetrafluoroethylene hydrophobic film layer, the air escapes uniformly from the outer wall of the microporous ceramic tube 2, forming a group of microbubbles with a diameter of 20-80μm. At the same time, the metering pump 6 is started, and the collector (such as xanthate) or flocculant (such as PAM) in the reagent storage tank 5 is delivered to each atomizing nozzle 8 through the multi-point injection pipeline 7. The reagent is sprayed in the form of droplets with a particle size of 10-30μm. The flotation process involves the release of microbubbles into the mixing zone at the bottom of the flotation tank 1, where they come into full contact with the rising microbubbles to form mineralized bubbles. These mineralized bubbles carry heavy metal complexes, oil droplets, and colloidal particles to the surface, where they aggregate to form a foam layer. A visual recognition camera 12 continuously captures images of the overflow weir 13 area, and a PLC controller 16 performs grayscale segmentation on each frame, calculating the percentage of white area (foam) pixels. When the percentage exceeds 70%, the PLC controller 16 outputs a pulse signal to start the servo motor 10. The servo motor 10 drives the scraper support 9 to rotate, causing the scraper arm 11 to move accordingly. The flexible silicone scraper 20 pushes the foam into the overflow weir 13, while the guide vanes 21 restrict the slurry from overflowing with the foam during this process. The flotation process continues, and the water quality feedback adjustment system collects turbidity, pH, and ORP data at the effluent end every 10 seconds. The PLC controller 16 judges the treatment effect based on historical data trends: if the turbidity decrease rate is detected to be less than 0.5% for three consecutive times... If the gas pressure reaches NTU / s, the gas supply pressure of the gas distribution chamber 3 will be automatically increased by 0.05 MPa to increase the microbubble density and enhance collection. After the flotation cycle ends (usually 2 hours), the PLC controller 16 will sequentially shut down the metering pump 6 and the compressed air source 4, and open the pneumatic drain valve (not labeled in the figure) at the bottom of the flotation tank 1 to drain the bottom sedimented sludge. Subsequently, the PLC controller 16 will start the high-pressure flushing pump (externally configured) to inject clean water into the gas distribution chamber 3 in reverse, forming a 1Hz frequency pulse water flow that lasts for 5 minutes to remove the blockages on the inner wall of the microporous ceramic tube 2 and the surface of the polytetrafluoroethylene membrane, restoring the aeration performance. The entire process requires no manual intervention, achieving continuous, stable, and efficient flotation treatment of metallurgical wastewater. In order to enable those skilled in the art to fully understand and implement the present invention, the following supplements the specific implementation principle of the present invention in conjunction with a specific application scenario. In the actual operation of a wastewater treatment plant in a copper smelter, the wastewater to be treated contains a Cu²⁺ concentration of approximately 35 mg / L, a COD of 180 mg / L, a suspended solids concentration of 220 mg / L, and is mixed with trace amounts of oil and colloidal silicates. The pH value fluctuates between 5.2 and 9.0, which is typical metallurgical wastewater with high ionic strength, high viscosity, and complex composition. After the wastewater enters the flotation equipment described in this invention, it first flows into the flotation tank 1 through the inlet 22. At this time, the ultrasonic level gauge 14 detects the liquid level in the tank in real time and transmits a 4-20mA signal to the PLC controller 16. The PLC controller 16 compares the current liquid level with the preset target value of 1150mm. If the deviation exceeds ±10mm, it outputs an adjustment signal to the electric regulating valve 15 to dynamically adjust the inlet flow rate, ensuring that the effective water depth in the flotation zone is stable at 1150mm, thereby providing constant hydrodynamic conditions for the bubble rising path and avoiding foam layer disturbance or uneven overflow caused by liquid level fluctuations. After the compressed air source 4 is started, the pressure is stabilized to 0.3MPa by the pressure reducing valve and enters the gas distribution chamber 3. The honeycomb array of through holes (2mm in diameter, 5mm in spacing) on ​​the pressure stabilizing plate in the chamber rectifies and equalizes the airflow, keeping the pressure difference at the inlet of each microporous ceramic tube 2 within ±0.02MPa, ensuring simultaneous gas production from multiple tubes. When the compressed air passes through the wall of the microporous ceramic tube 2 (pore diameter 10–50μm, porosity ≥40%), a low surface energy interface is formed on the surface of the polytetrafluoroethylene hydrophobic film layer, which promotes the gas phase to preferentially wet the film layer rather than be wetted by wastewater. This reduces the bubble detachment resistance, making the diameter of the escaping bubbles concentrated in the 20–80μm range, with a distribution standard deviation of less than 15μm, significantly increasing the specific surface area of ​​microbubbles and the probability of collision with pollutants. This structure avoids the problem of concentrated energy consumption caused by high shear in traditional jet generators and can achieve efficient microbubble generation without the need for a circulating pump. Meanwhile, metering pump 6 draws sodium xanthate collector solution from reagent storage tank 5 and delivers it to 13 atomizing nozzles 8 via multi-point injection pipeline 7. Each atomizing nozzle 8 breaks the reagent into fine droplets of 10–30 μm in a swirling manner, with its axis tilted at 30° toward the outlet of microporous ceramic tube 2, so that the reagent spray cone accurately covers the initial rising area of ​​microbubbles. In this area, droplets and microbubbles undergo high-frequency turbulent collisions, and reagent molecules are rapidly adsorbed onto the surface of heavy metal complexes and oil droplets, reducing their interfacial tension and promoting the formation of mineralized bubbles. Since the atomizing nozzle 8 is equipped with a one-way check valve with an opening pressure of 0.05 MPa at the rear end, even if metering pump 6 stops, the static pressure (approximately 0.012 MPa) generated by the 1.2 m water column in the flotation tank 1 is insufficient to overcome the preload of the check valve spring, effectively preventing wastewater from backflowing and contaminating the reagent system. As mineralized bubbles continue to rise, a foam layer containing Cu²⁺-xanthate complex, colloidal particles, and emulsified oil accumulates on the liquid surface. The visual recognition camera 12 continuously captures images of the overflow weir 13 area at a frame rate of 30fps. The PLC controller 16 uses a fixed threshold method to binarize the images, identifying pixels with grayscale values ​​higher than 200 as foam areas. When the proportion of foam pixels exceeds 70%, the PLC controller 16 outputs a pulse signal to drive the servo motor 10, causing the scraper support 9 to slowly rotate around the horizontal axis. Rotate; the scraper arm 11 moves accordingly, and its bottom flexible silicone scraper 20 gently pushes the foam in a line contact manner. Because the bottom of the scraper 20 is strictly flush with the top surface of the overflow weir 13, it only scrapes off the foam layer without disturbing the clear liquid phase below. During the scraping process, the guide vane 21 guides the foam flow to the center of the overflow weir 13 at a 15° angle. At the same time, its arc-shaped structure forms a local low-pressure zone in front of the movement, which inhibits the slurry from overflowing with the foam, so that the solid content of the foam product is less than 5%, which is significantly better than the entrainment rate of more than 12% of the traditional rigid scraper. The water quality feedback adjustment system synchronously collects data from the online turbidity sensor 17, pH electrode 18, and ORP probe 19 every 10 seconds. When the detected turbidity is 95 NTU, ORP is -250 mV, and pH is 5.8, the PLC controller 16 determines that the system is in a high reducing and high turbidity state and automatically increases the operating frequency of the metering pump 6 by 15% from the reference value to enhance the collector dosage to cope with sudden loads. If subsequent monitoring shows that the turbidity decrease rate is less than 0.5 NTU / s for three consecutive times, the PLC controller 16 instructs the pressure reducing valve of the compressed air source 4 to increase the output pressure by 0.05 MPa, thereby increasing the gas production of the microporous ceramic tube 2 by about 18%, increasing the microbubble density, and enhancing the scavenging effect on fine suspended solids. When the pH rises to 8.7, the PLC controller 16 triggers the three-way switching valve to switch the reagent branch to dilute sulfuric acid solution, realizing adaptive acid-base balance adjustment and maintaining the optimal flotation pH window. After the flotation cycle ends (set to 2 hours), the PLC controller 16 sequentially shuts down the metering pump 6 and the compressed air source 4. After a 10-second delay, it opens the bottom pneumatic drain valve to discharge the high-density sludge that has settled at the bottom of the tank. Then, the external high-pressure flushing pump is started to inject 0.6MPa clean water into the gas distribution chamber 3 in reverse. The water flows outward through the inner cavity of the microporous ceramic tube 2 in a pulsed manner. The intermittent water flow at a frequency of 1Hz causes the metal hydroxide and organic film attached to the surface of the polytetrafluoroethylene hydrophobic membrane to undergo periodic peeling. After 5 minutes of cleaning, the micropore flux recovery rate reaches more than 98%, ensuring the stability of the microbubble performance in the next cycle. The entire process is controlled by the PLC controller 16 in a closed loop without manual intervention, achieving efficient, stable, and low-energy removal of low-concentration heavy metals and colloidal pollutants under complex metallurgical wastewater conditions.

[0021] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A flotation device for mineral processing and metallurgical wastewater, characterized in that, It includes a flotation tank (1), a microbubble generating module, an adaptive reagent dosing unit, a foam recognition and scraping mechanism, a liquid level linkage control component, and a water quality feedback adjustment system; The flotation tank (1) is a rectangular closed structure with an inlet (22) at the bottom and an overflow weir (13) at the top. The microbubble generating module is installed on the inner side of the bottom of the flotation tank (1) and includes several microporous ceramic tubes (2) arranged in parallel. The microporous ceramic tubes (2) are fixed to the bottom plate of the flotation tank (1) by flanges. One end is connected to the compressed air source (4) through the gas distribution chamber (3), and the other end is closed. The adaptive reagent dosing unit includes a reagent storage tank (5), a metering pump (6), and a multi-point injection pipeline (7). The multi-point injection pipeline (7) is arranged 200 mm above the microporous ceramic tubes (2) along the length of the flotation tank (1). Multiple atomizing nozzles (8) are spaced on it. The atomizing nozzles (8) are installed at an angle of 30° towards the outlet of the microporous ceramic tubes (2). The foam identification and scraping mechanism includes a scraper bracket (9) spanning the top of the flotation tank (1), a servo motor (10), a scraper arm (11), and a visual recognition camera (12). The scraper bracket (9) is mounted on the outer walls of both sides of the flotation tank (1) through bearing seats at both ends. The output shaft of the servo motor (10) is connected to one end of the scraper bracket (9) through a coupling. The scraper arm (11) is vertically welded to the bottom of the scraper bracket (9). The visual recognition camera (12) is fixed above one side of the flotation tank (1) through an L-shaped bracket, with the lens facing the overflow weir (13) area. The liquid level linkage control component includes an ultrasonic level gauge (14), an electric regulating valve (15), and a PLC controller (16). The ultrasonic level gauge (14) is installed in the middle of the inner side wall of the flotation tank (1), and the electric regulating valve (15) is connected in series on the inlet (22) pipe. The water quality feedback adjustment system includes an online turbidity sensor (17), a pH electrode (18), and an ORP probe (19). The online turbidity sensor (17), pH electrode (18), and ORP probe (19) are all installed on the inner wall of the outlet end of the flotation tank (1) through threaded interfaces. The PLC controller (16) is electrically or signal connected to the ultrasonic level gauge (14), the electric regulating valve (15), the metering pump (6), the servo motor (10), the visual recognition camera (12), the online turbidity sensor (17), the pH electrode (18), and the ORP probe (19).

2. The flotation equipment for mineral processing and metallurgical wastewater according to claim 1, characterized in that, The microporous ceramic tube (2) has a pore size of 10–50 μm, a porosity of not less than 40%, and a wall thickness of 5 mm. Each microporous ceramic tube (2) is covered with a hydrophobic polytetrafluoroethylene film with a thickness of 0.2 mm. The gas distribution chamber (3) is equipped with a pressure stabilizing plate, and the pressure stabilizing plate is provided with a honeycomb-shaped through-hole array with a through-hole diameter of 2 mm and a hole spacing of 5 mm.

3. The flotation equipment for mineral processing and metallurgical wastewater according to claim 1, characterized in that, The multi-point injection pipeline (7) is made of 316L stainless steel with an inner diameter of 15mm; the atomizing nozzle (8) has a swirling structure with a nozzle diameter of 0.8mm and an injection angle of 60°; and each atomizing nozzle (8) is equipped with a one-way check valve at its rear end.

4. The flotation equipment for mineral processing and metallurgical wastewater according to claim 1, characterized in that, The scraper arm (11) is equipped with a flexible silicone scraper strip (20) at its lower end. The flexible silicone scraper strip (20) is embedded in the groove on the bottom surface of the scraper arm (11) through a snap-fit ​​structure, and its bottom is flush with the top surface of the overflow weir (13). The scraper arm (11) is provided with guide vanes (21) on both sides, and the guide vanes (21) are at an angle of 15° with the horizontal plane.

5. The flotation equipment for mineral processing and metallurgical wastewater according to claim 1, characterized in that, The visual recognition camera (12) is an industrial-grade CMOS image sensor with a resolution of 1920×1080, a frame rate of 30fps, a lens focal length of 12mm, and is equipped with an infrared fill light; the PLC controller (16) has a pre-stored foam grayscale threshold model, which is used to determine whether to start the servo motor (10) based on the proportion of white area in the image.

6. The flotation equipment for mineral processing and metallurgical wastewater according to claim 1, characterized in that, The online turbidity sensor (17) has a measurement range of 0–1000 NTU and a response time of 2 seconds; the pH electrode (18) is a glass composite electrode with a measurement range of 0–14; the ORP probe (19) uses a platinum sensing head with a measurement range of -1000 to +1000 mV.

7. The flotation equipment for mineral processing and metallurgical wastewater according to claim 1, characterized in that, The PLC controller (16) dynamically adjusts the start-stop frequency and flow rate of the metering pump (6) based on real-time data from the online turbidity sensor (17), pH electrode (18), and ORP probe (19). When the turbidity is higher than 80 NTU and the ORP is lower than -200 mV, the PLC controller (16) increases the flow rate of the metering pump (6) by 15%. When the pH value is lower than 6.5 or higher than 8.5, the PLC controller (16) controls the reagent type switching valve to switch to the acidic or alkaline regulator branch.

8. The working method of a flotation device for mineral processing and metallurgical wastewater according to claim 1, characterized in that, The specific operating steps of this working method are as follows: Step 1: Metallurgical wastewater enters the flotation tank (1) through the inlet (22). The ultrasonic level gauge (14) monitors the liquid level in the tank in real time. When the liquid level is lower than the set value, the PLC controller (16) controls the electric regulating valve (15) to increase the inlet flow rate and maintain the liquid level at 50mm below the overflow weir (13); Step 2: Compressed air enters the microporous ceramic tube (2) through the gas distribution chamber (3) to form a group of microbubbles with a diameter of 20–80μm. During the rise of the bubbles, they are mixed with the atomized reagent sprayed by the multi-point injection pipeline (7). The reagent droplet size is 10–30μm, forming mineralized bubbles; Step 3 Step 3: Mineralized bubbles rise to the liquid surface to form a foam layer. The visual recognition camera (12) collects images of the overflow weir (13) area, and the PLC controller (16) performs grayscale analysis. When the foam coverage area exceeds 70%, the servo motor (10) is started to drive the scraper bracket (9) to rotate, and the flexible silicone scraper (20) pushes the foam into the overflow weir (13). Step 4: The online turbidity sensor (17), pH electrode (18), and ORP probe (19) collect effluent water quality data every 10 seconds. The PLC controller (16) dynamically adjusts the dosage and type of reagents based on the multi-parameter fusion results. If the turbidity decrease rate is less than 0.5 for three consecutive tests. If NTU / s, the gas distribution chamber (3) will automatically increase the gas supply pressure by 0.05 MPa; Step 5: After the flotation process is completed, the PLC controller (16) will shut off the metering pump (6) and the compressed air source (4), open the bottom drain valve to drain the residual sludge, and start the high-pressure flushing pump to perform reverse pulse cleaning on the microporous ceramic tube (2). The cleaning cycle is 5 minutes and the pulse frequency is 1Hz.

9. The working method of a flotation device for mineral processing and metallurgical wastewater according to claim 8, characterized in that, In step two, the polytetrafluoroethylene hydrophobic film layer on the outer surface of the microporous ceramic tube (2) causes microbubbles to escape uniformly from the tube wall, and the pressure stabilizing plate in the gas distribution chamber (3) distributes the compressed air pressure evenly to each microporous ceramic tube (2).

10. The working method of a flotation device for mineral processing and metallurgical wastewater according to claim 8, characterized in that, In step three, the guide vanes (21) on both sides of the scraper arm (11) guide the foam to concentrate towards the overflow weir (13) during the scraping process and suppress slurry entrainment.

Images