Heavy metal wastewater treatment equipment and treatment method

Abstract

The invention discloses heavy metal wastewater treatment equipment and a treatment method. The equipment adopts a vertical coaxial integrated structure, the upper part is a barrel reaction area, and the bottom is provided with a high-frequency ultrasonic vibrator and is embedded with an electromagnetic coil group; the lower cyclone separation cavity is directly communicated with the reaction area through a tangential water inlet, a spiral light slag cyclone channel is arranged in the circumferential direction of the lower cyclone separation cavity to be communicated with the outer flow port, and a conical heavy slag collection channel is arranged at the bottom to be communicated with the inner flow port. The treatment method comprises the following steps: performing ultrasonic magnetic seed activation reaction, and synchronously applying ultrasonic cavitation and an axial magnetic field to form density gradient magnetic floc; performing double-vortex grading separation, centrifugally discharging light slag flocs through a spiral channel, and performing gravity concentration on heavy slag flocs in a conical channel; and regenerating and recycling the magnetic seeds. Transition crushing is eliminated through coaxial integration of reaction and separation, light / heavy slag flocs are captured in combination with double-vortex field grading, the problems of low light slag separation efficiency, large occupied area and high sludge water content in a traditional process are solved, and intensive and efficient treatment and resource recovery of heavy metal wastewater are achieved.

Description

Technical Field

[0001] This invention relates to a wastewater treatment device and method, and more particularly to a heavy metal wastewater treatment device and method. Background Technology

[0002] In the field of heavy metal wastewater treatment, chemical precipitation combined with cyclone separation is the current mainstream process, but there are still two major bottleneck problems: one is the low separation efficiency of light flocs, and the other is the loss of space and efficiency due to the separation of reaction and separation units. Hydrocyclone separation technology relies on centrifugal force to achieve solid-liquid separation, but its ability to capture low-density heavy metal flocs (such as hydroxides and organic complexes) is severely insufficient. Due to the small density difference between light flocs and wastewater, traditional hydrocyclones cannot provide sufficient separation driving force, resulting in a large amount of light sludge flocs escaping with the effluent. To meet discharge standards, secondary sedimentation tanks are often required in series, which not only prolongs the treatment time but also causes floc breakage due to pipeline transportation in the transition section, further reducing the overall separation efficiency.

[0003] Meanwhile, the existing process sets up the reaction tank and the hydrocyclone separator separately, which has significant drawbacks. The reaction unit and the separation unit need to be built separately, which increases the floor space by more than 40% and results in low space utilization. During the process of transporting wastewater from the reaction zone to the separation zone, the shear force of the pipeline causes damage to the magnetic floc structure, reduces the subsequent separation effect, and results in damage to the integrity of the floc.

[0004] The aforementioned problems have hindered the intensive development of heavy metal wastewater treatment technology, and there is an urgent need to develop a new type of equipment and process with high integration that can simultaneously solve the problems of light slag capture and floc protection. Summary of the Invention

[0005] To address the shortcomings of the aforementioned technologies, this invention provides a heavy metal wastewater treatment device and treatment method.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a heavy metal wastewater treatment device, comprising: A vertically arranged cylindrical reaction zone and a coaxially connected cyclone separation chamber; The reaction zone cylinder has an upper opening, and a high-frequency ultrasonic transducer is installed on the bottom plane of the cylinder; an electromagnetic coil assembly is embedded in the inner wall of the cylinder. The upper end of the cyclone separation chamber is provided with a tangential water inlet, which is flush with the plane of the ultrasonic transducer; the circumferential wall of the cyclone separation chamber is provided with a spirally extending light slag cyclone channel, which has an outflow port; the lower part of the cyclone separation chamber is provided with a conical heavy slag collection channel, which has an inflow port.

[0007] Furthermore, the spiral path of the light slag cyclone channel is designed with a constant pitch, and the pitch value is 0.55-0.65 times the diameter of the cyclone separation chamber.

[0008] Furthermore, the high-frequency ultrasonic transducer operates at a frequency of 38-42kHz and has a power density of 0.7-0.9W / cm².

[0009] Furthermore, the electromagnetic coil assembly covers 60%-80% of the height of the reaction zone.

[0010] Furthermore, the surface of the high-frequency ultrasonic transducer mounted on the bottom plane of the cylinder is coplanar with the bottom surface of the cylinder.

[0011] Furthermore, the upper end of the heavy slag collection channel has a large diameter that connects to the center of the bottom of the cyclone separation chamber, while the lower end narrows into a vertically downward-facing heavy slag inlet.

[0012] Furthermore, control valves are installed on both the outflow port and the inflow port.

[0013] A method for treating heavy metal wastewater using a heavy metal wastewater treatment device, comprising the following steps: S1. Ultrasonic magnetic seed activation reaction: Heavy metal wastewater, SiO2-coated Fe3O4 magnetic seeds and precipitant are introduced into the reaction zone of the cylinder through the upper opening; high-frequency ultrasonic transducer is started to treat the magnetic seeds at 38–42kHz and 0.7–0.9W / cm² for 8–15 minutes to form nano-etching pits on the surface of the magnetic seeds. A synchronously activated electromagnetic coil group applies an axial magnetic field of 0.3–0.5T; S2. Dual-vortex staged separation: After the reaction, the wastewater enters the vortex separation chamber through the tangential inlet at a flow rate of 18–25 m / s; the pressure in the light slag vortex channel is controlled at 0.12–0.18 MPa, so that the light slag flocs with a density <2.2 g / cm³ are discharged through the outer outlet; the heavy slag flocs with a density ≥2.2 g / cm³ settle along the heavy slag collection channel 204 and are output as sludge with a solids content ≥20% through the inner outlet; S3. Magnetic seed directional regeneration: The sludge discharged from the inlet is transported to a magnetic separator, where magnetic seeds are separated under a magnetic field of 0.4–0.6T; the magnetic seeds are regenerated by hot acid washing at 120–130℃ and then reused in S1.

[0014] Furthermore, in step S1, the amount of magnetic seed added is 1.1–1.3 times the total molar concentration of heavy metal ions in the wastewater, and the depth of the nano-etching pit is 50–200 nm.

[0015] Further, in step S2, a cationic flocculant, polydimethyldiallyl ammonium chloride, is injected into the heavy slag collection channel 204 at a dosage of 0.8–1.5 mg / L; the light slag discharged from the outlet enters the electrocatalytic oxidation unit and is treated for 20–30 min at a boron-doped diamond anode and a current density of 8–12 mA / cm².

[0016] This invention discloses a heavy metal wastewater treatment device and method. Addressing the low separation efficiency of light flocs in the prior art, this invention achieves a breakthrough through a dual-vortex field synergistic separation mechanism and magnetic seed density gradient pre-control technology: a spiral light slag vortex channel is set on the circumferential wall of the vortex separation chamber to maintain a continuous centrifugal force field, forcing low-density light slag flocs to vortex and discharge; simultaneously, a conical heavy slag collection channel is constructed at the bottom of the separation chamber to concentrate high-density heavy slag flocs through gravity sedimentation. In conjunction with an electromagnetic coil group, an axial magnetic field is applied to drive the magnetic seeds to oriented alignment, pre-forming density-differentiated magnetic flocs, creating a physical basis for graded separation. This scheme significantly improves light slag capture efficiency, completely eliminates the need for a secondary sedimentation unit, and achieves sludge reduction at the source. Addressing the layout defects caused by the separate reaction and separation units, an innovative vertical coaxial integrated structure is adopted: the cylindrical reaction zone is directly coupled to the vortex separation chamber, and the tangential inlet is precisely flush with the ultrasonic transducer plane, completely eliminating transition pipes. This approach not only significantly reduces the equipment footprint but also ensures that the magnetic flocs formed by ultrasonic activation are transported to the separation chamber without breakage, guaranteeing the integrity of the floc structure and maximizing the efficiency of the dual-vortex classification. Furthermore, by combining the magnetic seed-oriented regeneration and reuse within the heavy slag channel with the electrocatalytic deep purification technology for light slag, a closed-loop treatment system integrating reaction activation, efficient separation, and resource regeneration is formed. Ultimately, while overcoming the challenges of light slag separation, a comprehensive leap forward is achieved in equipment intensification, sludge reduction, and high-quality effluent. Attached Figure Description

[0017] Figure 1 This is a structural disassembly diagram of the present invention.

[0018] Figure 2 This is a schematic diagram of the cyclone separation chamber of the present invention.

[0019] Figure 3 This is a cross-sectional view of the present invention.

[0020] In the diagram: 100, reaction zone of the cylinder; 200, cyclone separation chamber; 101, upper opening; 102, electromagnetic coil group; 103, high-frequency ultrasonic transducer; 201, tangential water inlet; 202, light slag cyclone channel; 203, outflow port; 204, heavy slag collection channel; 205, inflow port. Detailed Implementation

[0021] The following is in conjunction with the appendix Figure 1-3 The present invention will be further described in detail below with reference to specific embodiments.

[0022] Example 1:

[0023] like Figure 1-3 The heavy metal wastewater treatment equipment shown includes a vertically arranged cylindrical reaction zone 100 and a coaxially connected cyclone separation chamber 200. The cylinder of the reaction zone 100 has an upper opening 101, and a high-frequency ultrasonic transducer 103 is installed on the bottom plane of the cylinder; an electromagnetic coil group 102 is embedded in the inner wall of the cylinder; specifically, the upper part of the cylinder cavity serves as the reaction zone, its upper opening serves as the reagent dosing end and the heavy metal wastewater dosing end, and a high-frequency ultrasonic transducer plane is installed at the bottom of the cylinder to promote the co-precipitation of magnetic seeds and heavy metals through ultrasonic cavitation to form magnetic flocs; an electromagnetic coil group is embedded in the inner wall of the cylinder.

[0024] The upper end of the cyclone separation chamber 200 is provided with a tangential inlet 201, which is flush with the plane of the ultrasonic transducer; the circumferential wall of the cyclone separation chamber 200 is provided with a spirally extending light slag cyclone channel 202, which has an outflow port 203; the lower part of the cyclone separation chamber 200 is provided with a conical heavy slag collection channel 204, which has an inflow port 205.

[0025] Specifically, a cyclone separation chamber is provided at the bottom, with a tangential inlet at the top. The tangential inlet is flush with the plane of the high-frequency ultrasonic transducer and connects the cylinder and the light slag cyclone channel. The light slag cyclone channel is located on the circumferential wall of the cyclone separation chamber and is always connected to the separation chamber of the cyclone separation chamber along the spiral path. The cyclone channel forms an outflow port. A conical heavy slag cyclone collection channel is formed at the bottom of the cyclone separation chamber. The heavy slag cyclone collection channel connects upward to the separation chamber of the cyclone separation chamber and downward to a vertically downward inflow port. The light slag cyclone channel and the heavy slag cyclone collection channel form a double vortex flow field, discharging light slag magnetic flocs and heavy slag magnetic flocs in stages. The upper end of the heavy slag collection channel 204 has a large diameter that connects to the center of the bottom of the separation chamber of the cyclone separation chamber 200, and the lower end narrows into a vertically downward heavy slag inflow port 205. Control valves are provided on both the outflow port 203 and the inflow port 205.

[0026] Preferably, the spiral path of the light slag cyclone channel 202 is designed with a constant pitch, and the pitch value is 0.55-0.65 times the diameter of the cyclone separation chamber 200. The high-frequency ultrasonic transducer 103 operates at a frequency of 38-42kHz and has a power density of 0.7-0.9W / cm². The electromagnetic coil group 102 covers 60%-80% of the height of the reaction zone.

[0027] The surface of the high-frequency ultrasonic transducer 103, which is installed on the bottom plane of the cylinder, is coplanar with the bottom plane of the cylinder, eliminating the transition channel between the reaction zone and the separation chamber of traditional equipment and preventing the flocs from breaking during the transportation process.

[0028] During operation, heavy metal wastewater and magnetic seeds are introduced into the reaction zone of the cylinder through the upper opening. The cavitation effect generated by the high-frequency ultrasonic transducer creates micro-corrosion pits on the surface of the magnetic seeds, promoting the adsorption and co-precipitation of heavy metal ions. Simultaneously, an axial magnetic field is applied by the electromagnetic coil on the cylinder wall, driving the magnetic seeds to oriented and form density-differentiated magnetic flocs. After the reaction, the wastewater directly enters the cyclone separation chamber through the tangential inlet, avoiding floc breakage. Under the action of the double vortex flow field: the light slag flocs are dominated by centrifugal force, rotating outward along the spiral light slag channel and discharged through the outflow port; the heavy slag flocs are dominated by gravity, settling towards the center of the separation chamber and concentrating along the conical heavy slag channel, outputting high-solids-content sludge through the inner outlet. The spiral path of the light slag channel is connected to the separation chamber throughout, maintaining the continuity of centrifugal force, while the conical structure of the heavy slag channel enhances gravity settling, achieving natural density-based classification of the flocs.

[0029] Example 2:

[0030] This invention also discloses a treatment method for heavy metal wastewater treatment equipment, characterized by comprising the following steps: S1. Ultrasonic magnetic seed activation reaction: Heavy metal wastewater, SiO2-coated Fe3O4 magnetic seeds, and precipitant are introduced into the reaction zone 100 of the cylinder through the upper opening 101; a high-frequency ultrasonic transducer 103 is activated to treat the seeds at 38–42 kHz and 0.7–0.9 W / cm² for 8–15 min, forming nano-etching pits on the surface of the magnetic seeds; an electromagnetic coil group 102 is simultaneously activated to apply an axial magnetic field of 0.3–0.5 T; wherein, the 38–42 kHz ultrasonic waves generate cavitation microjets (velocity >100 m / s) on the surface of the magnetic seeds, which impact and form 50–200 nm etching pits, increasing the specific surface area by 40% and improving the adsorption capacity for Cd²⁺ and Pb²⁺; S2. Dual-vortex staged separation: After the reaction, the wastewater enters the vortex separation chamber 200 through the tangential inlet 201 at a flow rate of 18–25 m / s, enhancing the density difference separation effect; the pressure inside the light slag vortex channel 202 is controlled at 0.12–0.18 MPa to suppress air binding and ensure the stability of the external vortex flow field, so that the light slag flocs with a density <2.2 g / cm³ are discharged through the external outlet 203; the heavy slag flocs with a density ≥2.2 g / cm³ settle along the heavy slag collection channel 204 and are output as sludge with a solids content ≥20% through the internal outlet 205; S3. Directional regeneration of magnetic seeds: The sludge discharged from the inlet 205 is transported to the magnetic separator, where magnetic seeds are separated under a magnetic field of 0.4–0.6T; the magnetic seeds are regenerated by hot acid washing at 120–130℃ and then reused in S1.

[0031] In step S1, the amount of magnetic seed added is 1.1–1.3 times the total molar concentration of heavy metal ions in the wastewater, and the depth of the nano-etching pit is 50–200 nm.

[0032] In step S2, cationic flocculant polydimethyldiallyl ammonium chloride is injected into the heavy slag collection channel 204 at a dosage of 0.8–1.5 mg / L; the light slag discharged from the outlet 203 enters the electrocatalytic oxidation unit and is treated for 20–30 min at a boron-doped diamond anode and a current density of 8–12 mA / cm².

[0033] The treatment method in Example 2 precisely constructs nano-etching pits on the surface of magnetic seeds through ultrasonic cavitation, and simultaneously pre-aggregates magnetic flocs with distinct density gradients using a magnetic field. Combined with the synergistic effect of centrifugal force and gravity in a dual-vortex flow field, it achieves efficient and natural classification of light and heavy slag. In-situ addition of flocculants in the heavy slag channel enhances the settling density of heavy slag, and electrocatalytic oxidation of light slag deeply breaks down complexes. Combined with closed-loop regeneration and reuse of magnetic seeds, it achieves deep purification of heavy metals and reduction of sludge at the source while preventing floc breakage in the transition section, forming an intensive and efficient treatment paradigm that integrates "reaction, separation, and regeneration".

[0034] In summary, this invention addresses the low efficiency of light floc separation in the prior art by achieving a breakthrough through a dual-vortex field synergistic separation mechanism and magnetic seed density gradient pre-control technology: a spiral light slag vortex channel is set on the circumferential wall of the vortex separation chamber to maintain a continuous centrifugal force field, forcing low-density light slag flocs to vortex outwards and be discharged; simultaneously, a conical heavy slag collection channel is constructed at the bottom of the separation chamber to concentrate high-density heavy slag flocs by gravity settling. Combined with an electromagnetic coil group applying an axial magnetic field to drive the magnetic seeds to oriented alignment, pre-forming density-differentiated magnetic flocs, creating a physical basis for graded separation. This scheme significantly improves light slag capture efficiency, completely eliminates the need for a secondary settling unit, and achieves sludge reduction at the source. Addressing the layout defects caused by the separate reaction-separation units, an innovative vertical coaxial integrated structure is adopted: the cylindrical reaction zone is directly coupled to the vortex separation chamber, and the tangential inlet is precisely flush with the ultrasonic transducer plane, completely eliminating transition pipes. This not only significantly reduces the equipment footprint but also ensures that the magnetic flocs formed by ultrasonic activation are transported to the separation chamber without breakage, guaranteeing the integrity of the floc structure and maximizing the efficiency of dual-vortex grading. By further combining magnetic seed directional regeneration and reuse in the heavy slag channel with electrocatalytic deep purification technology for light slag, a closed-loop treatment system integrating reaction activation, efficient separation, and resource regeneration is formed. Ultimately, while overcoming the problem of light slag separation, a comprehensive leap forward is achieved in equipment intensification, sludge reduction, and high-quality effluent.

[0035] The above embodiments are not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the technical solution of the present invention are also within the protection scope of the present invention.

Claims

1. A heavy metal wastewater treatment device, characterized in that, include: The vertically arranged cylindrical reaction zone (100) and the coaxially connected cyclone separation chamber (200) are also present. The reaction zone (100) has an upper opening (101) and a high-frequency ultrasonic transducer (103) is installed on the bottom plane of the cylinder; an electromagnetic coil group (102) is embedded in the inner wall of the cylinder. The upper end of the cyclone separation chamber (200) is provided with a tangential inlet (201), which is flush with the plane of the ultrasonic transducer; the circumferential wall of the cyclone separation chamber (200) is provided with a spirally extended light slag cyclone channel (202), which has an outflow port (203); the lower part of the cyclone separation chamber (200) is provided with a conical heavy slag collection channel (204), which has an inflow port (205).

2. The heavy metal wastewater treatment equipment according to claim 1, characterized in that: The spiral path of the light slag cyclone channel (202) is designed with equal pitch, and the pitch value is 0.55-0.65 times the diameter of the cyclone separation chamber (200).

3. The heavy metal wastewater treatment equipment according to claim 1, characterized in that: The high-frequency ultrasonic transducer (103) operates at a frequency of 38-42kHz and has a power density of 0.7-0.9W / cm².

4. The heavy metal wastewater treatment equipment according to claim 1, characterized in that: The electromagnetic coil assembly (102) covers 60%-80% of the height of the reaction zone.

5. The heavy metal wastewater treatment equipment according to claim 1, characterized in that: The surface of the high-frequency ultrasonic transducer (103) mounted on the bottom plane of the cylinder is coplanar with the bottom plane of the cylinder.

6. The heavy metal wastewater treatment equipment according to claim 1, characterized in that: The upper end of the heavy slag collection channel (204) is connected to the center of the bottom of the cyclone separation chamber (200) with a large diameter, and the lower end is narrowed into a vertically downward heavy slag inlet (205).

7. The heavy metal wastewater treatment equipment according to claim 1, characterized in that: Both the outflow port (203) and the inflow port (205) are equipped with control valves.

8. A method for treating heavy metal wastewater using a heavy metal wastewater treatment device, applied to the heavy metal wastewater treatment device according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Ultrasonic magnetic seed activation reaction: Heavy metal wastewater, SiO2-coated Fe3O4 magnetic seeds and precipitant are introduced into the reaction zone (100) of the cylinder through the upper opening (101); the high-frequency ultrasonic transducer (103) is activated to treat the seeds for 8–15 min at 38–42 kHz and 0.7–0.9 W / cm², so that nano-etching pits are formed on the surface of the magnetic seeds; the electromagnetic coil group (102) is activated simultaneously to apply an axial magnetic field of 0.3–0.5 T. S2. Double vortex staged separation: After the reaction, the wastewater enters the vortex separation chamber (200) through the tangential inlet (201) at a flow rate of 18–25 m / s; the pressure in the light slag vortex channel (202) is controlled at 0.12–0.18 MPa, so that the light slag flocs with a density <2.2 g / cm³ are discharged through the outer outlet (203); the heavy slag flocs with a density ≥2.2 g / cm³ settle along the heavy slag collection channel (204) and are output as sludge with a solid content ≥20% through the inner outlet (205); S3. Magnetic seed directional regeneration: The sludge discharged from the inlet (205) is transported to the magnetic separator and separated into magnetic seeds under a magnetic field of 0.4–0.6T; the magnetic seeds are regenerated by hot acid washing at 120–130℃ and then reused in S1.

9. The treatment method of the heavy metal wastewater treatment equipment according to claim 8, characterized in that: In step S1, the amount of magnetic seed added is 1.1–1.3 times the total molar concentration of heavy metal ions in the wastewater, and the depth of the nano-etching pit is 50–200 nm.

10. The treatment method of the heavy metal wastewater treatment equipment according to claim 8, characterized in that: In step S2, cationic flocculant polydimethyldiallyl ammonium chloride is injected into the heavy slag collection channel (204) at a dosage of 0.8–1.5 mg / L; the light slag discharged from the outlet (203) enters the electrocatalytic oxidation unit and is treated for 20–30 min at a boron-doped diamond anode and a current density of 8–12 mA / cm².

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