Coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification

Abstract

The application discloses a coal-containing wastewater treatment system based on electric flocculation and centrifugal clarification, which comprises a coaxial rotating treatment unit, an outer shell anode rotating drum and an internal cathode pushing screw, the inner wall of the outer shell anode rotating drum is provided with asymmetric flow guide cutting ribs, local vortex is induced through a rotating speed difference, physical scouring and mechanical cutting are utilized to generate heavy phase solid particles, the insulation passivation layer is continuously stripped, the anode metal dissolution reaction is maintained, a centrifugal compaction reaction zone is constructed, metal cations are in-situ nucleated in the heavy phase coal slurry compaction layer, water is squeezed to form a high-density slurry cake, the internal cathode pushing screw is embedded with gradient micro-bubble rectifier plates to generate discrete micro-bubble groups, and the bubble groups are driven by centripetal buoyancy to capture colloidal particles to form a gas-solid composite light phase. The application realizes synchronous three-phase separation of the heavy phase, the liquid phase and the light phase in the same cavity, and solves the defect of separation efficiency reduction caused by anode passivation.

Description

Technical Field

[0001] This invention relates to the field of environmental water treatment technology, specifically to a coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification. Background Technology

[0002] Coal-containing wastewater mainly originates from coal washing, mine drainage, and industrial production processes such as coal chemical processing. This wastewater typically contains large amounts of suspended coal slime, clay minerals, and stable colloids. To achieve compliant discharge or water resource recycling, solid-liquid separation of coal-containing wastewater is necessary. In conventional environmental water treatment processes, electrocoagulation technology, because it requires no chemical additives and produces no secondary pollution, is often combined with centrifugal clarification technology and applied to the treatment of coal-containing wastewater.

[0003] In existing conventional treatment processes, electrocoagulation and centrifugal clarification are usually operated in series as independent equipment units. Coal-containing wastewater first enters the pre-static electrolytic cell. Under the action of DC electric field, the soluble metal anode undergoes oxidation and dissolution, releasing metal cations. The metal cations hydrolyze and polymerize to form polynuclear complexes. Through adsorption and entrapment, the suspended particles in the wastewater aggregate into flocs. The wastewater that has completed pre-flocculation is then pumped to the post-centrifugal separation equipment. The centrifugal force generated by the high-speed mechanical rotation is used to achieve the physical separation of flocs from the aqueous phase. In the pre-static electrolytic cell, the soluble metal anode plates are arranged statically in the cell. The flow of wastewater over the surface of the soluble metal anode plates is uniformly distributed, and there is a lack of a solid abrasive scouring control mechanism for the anode plate surface.

[0004] However, existing electrocoagulation treatment processes have technical defects. When treating high-turbidity coal-containing wastewater, fine coal slime particles and precipitates in the wastewater easily adhere to the surface of the static soluble anode. As the electrochemical reaction continues, an insulating passivation layer is generated on the anode surface. This layer blocks the direct contact between the metal substrate and the wastewater, hindering the continuous oxidation and dissolution of the anode metal. This leads to the stagnation of flocculant ion release and an increase in system circuit resistance, making it impossible to maintain the anode metal dissolution reaction stably. Consequently, the solid-liquid separation efficiency of the subsequent centrifugal clarification process decreases. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that in the treatment of high turbidity coal-containing wastewater in the prior art, an insulating passivation layer is easily formed on the surface of the soluble anode, which blocks the direct contact between the metal substrate and the wastewater, hinders the continuous oxidation and dissolution of the anode metal, and leads to an increase in the system circuit resistance and stagnation of flocculant ion release. As a result, the anode metal dissolution reaction cannot be maintained stably, which leads to a decrease in the solid-liquid separation efficiency of the subsequent centrifugal clarification process.

[0006] This invention provides a coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification, including a coaxial rotating treatment unit. The coaxial rotating treatment unit includes an outer anode drum, an inner cathode pusher screw, a central coaxial feed pipe, a high-current conductive slip ring assembly, a drive motor, and a planetary differential.

[0007] The outer shell anode drum forms the external pressure-bearing boundary and main body rotation support structure of the coaxial rotating processing unit. The main body of the outer shell anode drum is made of soluble metal material, and both ends of the outer shell anode drum are supported on the external base by bearing groups.

[0008] The internal cathode pusher screw is coaxially nested in the inner cavity of the outer anode drum. It has a hollow tubular hub and a spiral blade fixed to the outer surface of the hollow tubular hub. A preset radial operating gap is maintained between the outer edge of the spiral blade and the inner wall of the outer anode drum.

[0009] The central coaxial feed pipe extends into the hollow tubular hub along the rotation center axis of the outer shell anode drum, and the pipe wall has radial material distribution holes that connect the internal flow channel and the annular processing area inside the outer shell anode drum.

[0010] The high-current conductive slip ring assembly is mounted on the drive shaft end of the outer shell anode drum. The positive electrode brush terminal is conductively connected to the outer shell anode drum, and the negative electrode brush terminal is conductively connected to the internal cathode pusher screw after passing through the insulating sealing isolation ring. The insulating sealing isolation ring blocks the physical contact and current short-circuit path between the outer shell anode drum and the internal cathode pusher screw.

[0011] The drive motor outputs rotational power and distributes the speed through a planetary differential to keep the outer anode drum and the inner cathode pusher screw rotating in the same direction and maintain a constant speed difference. One end of the coaxial rotating processing unit is equipped with a heavy phase discharge port, and the other end is equipped with a middle section annular gap overflow weir. The hollow tubular hub of the inner cathode pusher screw is coaxially arranged with a light phase suction channel.

[0012] Coal-containing wastewater enters the annular treatment zone between the internal cathode pusher screw and the outer anode drum through the radial distribution hole. Under the action of centrifugal inertial force field, an annular liquid pool is formed along the inner wall. After the high-current conductive slip ring assembly is connected to the DC power supply, a radial DC electric field penetrating the liquid layer of the annular liquid pool is constructed between the internal cathode pusher screw and the outer anode drum, and the centrifugal separation field and electrochemical reaction field are loaded simultaneously.

[0013] Multiple asymmetric flow-guiding and cutting ribs are axially arranged on the inner wall of the outer anode drum. These ribs are distributed in a helical array, with the helix angle parameter matching the helix angle parameter of the internal cathode pusher screw. The cross-section of the asymmetric flow-guiding and cutting ribs has an asymmetric geometric profile, consisting of a gentle slope facing the flow and a steep cutting surface facing the flow. The angle between the gentle slope facing the flow and the tangent of the inner wall of the outer anode drum is set between 10 and 30 degrees, while the angle between the steep cutting surface facing the flow and the tangent of the inner wall of the outer anode drum is set between 75 and 90 degrees. When the fluid passes over the asymmetric guide cutting rib and enters the steep cutting surface region of the backflow, the flow channel cross-section undergoes abrupt change and generates local eddies. The local eddies carry heavy phase solid particles to form a mixed two-phase flow and generate fluid excitation. The mixed two-phase flow generates wall shear stress on the surface attachments. The magnitude of the wall shear stress is directly proportional to the product of the local friction coefficient, the local fluid density, and the square of the relative slip velocity. When the wall shear stress overcomes the surface adhesion, the physical scouring and mechanical cutting action helps to peel off the insulating passivation layer generated by the electrochemical reaction on the inner wall of the outer shell anode drum.

[0014] A centrifugal compaction reaction zone is formed between the outer anode drum and the inner cathode pusher screw. Heavy phase solid particles in the coal-containing wastewater settle and aggregate on the inner wall to form a wall-attached heavy phase coal slime compacted layer. The radial DC electric field drives the metal cations released by the outer anode drum to overcome the resistance of the free water phase medium to be squeezed outward and to electromigrate into the interior of the heavy phase coal slime compacted layer. The metal cations hydrolyze in the pores of the heavy phase coal slime compacted layer to generate polynuclear hydroxy complexes, which promote the in-situ nucleation of heavy phase solid particles to form a floc skeleton. When the radial centrifugal pressure is greater than the capillary force generated by the microporous capillaries inside the floc skeleton, the free water is squeezed out towards the axis of rotation. The heavy phase coal slime compacted layer solidifies to form a high-density mud cake, which is pushed to the heavy phase discharge port by the inner cathode pusher screw for discharge.

[0015] The internal cathode pusher screw has a gradient microbubble rectifier plate embedded in its spiral blades. The substrate is made of insulating and wear-resistant material. A cathode conductive mesh connected to the negative terminal is attached to the back-flow side surface. The gradient microbubble rectifier plate has an array of rectifier micropores that penetrate the thickness direction of the plate. The aperture size of the rectifier micropores is gradually distributed from small to large along the discharge axis. When the initial bubbles precipitated on the cathode conductive mesh surface overflow through the rectifier micropores, the rotational speed difference creates a local fluid shear rate on the front-flow side surface of the gradient microbubble rectifier plate. The magnitude of the local fluid shear rate is directly proportional to the radius of rotation of the gradient microbubble rectifier plate and the absolute value of the difference in rotational angular velocity between the outer anode drum and the internal cathode pusher screw, and inversely proportional to the thickness of the fluid shear boundary layer. The local fluid shear rate generates tangential fluid drag force to mechanically cut the initial bubbles, generating discrete microbubble groups with different particle sizes.

[0016] In the centrifugal force field, the density difference between the discrete microbubble swarm and the main liquid phase of the coal-containing wastewater generates a centripetal buoyancy pointing towards the central axis of rotation of the outer shell anode drum. The magnitude of the centripetal buoyancy is directly proportional to the product of the density difference between the main liquid phase of the coal-containing wastewater and the gas inside the individual bubbles, the volume of the individual bubbles, the square of the rotational angular velocity of the outer shell anode drum, and the gyration radius of the individual bubble. In the centripetal motion path, the discrete microbubble swarm captures unsettled fine colloidal particles by surface tension, combines to form a gas-solid composite light phase and enriches it in the region of the central axis of rotation. The fluid system inside the coaxial rotating treatment unit completes the three-phase physical stratification in the radial space. The outer heavy phase is transported to the heavy phase discharge port by the internal cathode pusher screw and discharged. The middle clarified liquid phase overflows and is discharged across the middle annular gap overflow weir. The gas-solid composite light phase collected in the central region is continuously extracted by the external vacuum pump through the light phase suction channel by applying suction negative pressure, realizing the synchronous three-phase separation process in the same structural cavity.

[0017] The present invention, by adopting the above technical solution, can bring the following beneficial effects:

[0018] 1. This invention arranges asymmetric flow-guiding and cutting ribs on the inner wall of the outer shell anode drum and uses the speed difference to drive coal-containing wastewater over the steep cutting surface to induce local eddies. This eddies carry heavy phase solid particles to form a mixed two-phase flow, generating wall shear stress on the surface deposits. The insulating passivation layer generated by the electrochemical reaction on the inner wall of the outer shell anode drum is peeled off by physical scouring and mechanical cutting. This allows the unoxidized metal base layer to be continuously exposed on the surface of the asymmetric flow-guiding and cutting ribs, thereby maintaining a stable anode metal dissolution reaction.

[0019] 2. This invention constructs a centrifugal compaction reaction zone between the outer shell anode drum and the inner cathode pusher screw, which promotes the accumulation of heavy phase solid particles to form a heavy phase coal slime compaction layer. The radial DC electric field drives metal cations to overcome the resistance of the aqueous medium and electromigrate into the interior of the heavy phase coal slime compaction layer. This promotes the in-situ nucleation and bridging process of heavy phase solid particles under pressure, thereby achieving separation and dehydration by isolating fluid shearing and squeezing free water towards the central axis of rotation to solidify and form a high-density mud cake.

[0020] 3. This invention achieves a synchronous three-phase separation effect by embedding a gradient microbubble rectifier plate with rectifier micropores of gradually varying pore size on the spiral blade body of the internal cathode pusher screw. The tangential fluid drag force generated by the rotation speed difference cuts the initial bubbles to generate discrete microbubble groups. Based on the centrifugal force field density difference, the discrete microbubble groups are driven to move in the opposite direction to capture unsettled fine colloidal particles and form a gas-solid composite light phase. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the coaxial rotation processing unit structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the topology of the coaxial rotation processing unit of the present invention;

[0023] Figure 3 This is a schematic diagram of the topology of a partial structure of the anode drum of the outer shell of the present invention;

[0024] Figure 4 This is a schematic diagram of a partial structure of the anode drum of the outer shell of the present invention.

[0025] Figure 5 This is a schematic diagram of the internal cathode feeding screw of the present invention;

[0026] Figure 6 This is a schematic diagram of the radial three-phase physical layering and output structure of the system of the present invention. Detailed Implementation

[0027] 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.

[0028] Example 1

[0029] See attached document Figure 1-2 The present invention provides a coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification, comprising: a coaxial rotating treatment unit 100, and further comprising: an outer shell anode drum 110, an inner cathode pusher screw 120, a central coaxial feed pipe 130, a high-current conductive slip ring assembly 140, a drive motor 180, and a planetary differential 190.

[0030] The outer shell anode drum 110 constitutes the external pressure-bearing boundary and main body rotation support structure of the coaxial rotating processing unit 100. The outer shell anode drum 110 adopts a multi-layer metal composite cylinder structure, including an outer pressure-bearing sleeve formed of high-strength structural steel and an inner sacrificial bushing that is detachably nested in the inner wall of the outer pressure-bearing sleeve. The main body material of the inner sacrificial bushing is made of soluble metal to form the consumable anode for the electrochemical reaction. Both ends of the outer shell anode drum 110 are supported on the external base by bearing assemblies.

[0031] The internal cathode pusher screw 120 is coaxially nested in the inner cavity of the outer anode drum 110. The internal cathode pusher screw 120 has a hollow tubular hub and helical blades fixed to the outer surface of the hollow tubular hub. A preset radial operating gap is maintained between the outer edge of the helical blades of the internal cathode pusher screw 120 and the inner wall of the outer anode drum 110. The radial operating gap constitutes a physical channel for fluid processing and solid phase discharge.

[0032] The central coaxial feed pipe 130 extends into the hollow tubular hub of the internal cathode pusher screw 120 along the rotation center axis of the outer shell anode drum 110. The pipe wall of the central coaxial feed pipe 130 is provided with radial distribution holes, which connect the internal flow channel of the central coaxial feed pipe 130 with the annular processing area in the inner cavity of the outer shell anode drum 110.

[0033] A high-current conductive slip ring assembly 140 is sleeved on the drive shaft end of the outer anode drum 110. The positive brush terminal of the high-current conductive slip ring assembly 140 is conductively connected to the outer anode drum 110. The negative brush terminal of the high-current conductive slip ring assembly 140 passes through the insulating sealing isolation ring and is conductively connected to the internal cathode pusher screw 120. The insulating sealing isolation ring blocks the physical contact and current short-circuit path between the internal cathode pusher screw 120 and the outer anode drum 110.

[0034] One end of the coaxial rotating processing unit 100 is provided with a heavy phase discharge port 150, and the other end of the coaxial rotating processing unit 100 is provided with a middle section annular gap overflow weir 160. The hollow tubular hub of the internal cathode pusher screw 120 is coaxially arranged with a light phase suction channel 170.

[0035] In the macroscopic workflow of the system, the outer anode drum 110 and the inner cathode pusher screw 120 are powered by a drive motor 180. The power of the drive motor 180 is distributed through a planetary differential 190 to maintain the outer anode drum 110 and the inner cathode pusher screw 120 rotating in the same direction and to maintain a constant speed difference. At this time, the speed difference exists within the coaxial rotation processing unit 100. Represented as:

[0036]

[0037] In the formula: This indicates the speed difference between the outer anode drum 110 and the inner cathode pusher screw 120; This indicates the absolute rotational speed of the outer casing anode drum 110; This indicates the absolute rotational speed of the internal cathode feed screw 120;

[0038] Coal-containing wastewater is pumped into the coaxial rotary treatment unit 100 through the central coaxial feed pipe 130, and then passes through the radial distribution hole into the annular treatment area between the internal cathode pusher screw 120 and the outer shell anode drum 110.

[0039] The coal-containing wastewater entering the annular treatment zone is subjected to centrifugal inertial force, forming an annular liquid pool that adheres to the inner wall of the outer anode drum 110. The solid particles in the coal-containing wastewater are subjected to radial centrifugal force. for:

[0040]

[0041] In the formula: This represents the radial centrifugal force experienced by solid particles; Indicates the mass of the monomeric solid particles; This indicates the rotational angular velocity of the outer casing anode drum 110; The radius of gyration indicating the location of the solid particle;

[0042] Simultaneously connect the high-current conductive slip ring assembly 140 to a DC power supply to construct a radial DC electric field penetrating the liquid layer of the annular liquid pool between the internal cathode pusher screw 120 and the outer shell anode drum 110.

[0043] The coaxial rotating treatment unit 100 synchronously loads centrifugal separation field and electrochemical reaction field in the internal physical space of the coaxial rotating treatment unit 100. The coal-containing wastewater synchronously undergoes anodic metal dissolution, electrochemical flocculation and centrifugal sedimentation in the annular liquid pool. Due to the difference in the density of each phase, the fluid system undergoes three-phase stratification in the radial dimension.

[0044] The speed difference drives the spiral blades of the internal cathode pusher screw 120 to generate axial thrust. The axial thrust will directionally transport the heavy phase solid material that has been enriched on the inner wall surface of the outer shell anode drum 110 and has been compacted in situ to the heavy phase discharge port 150, and finally discharge it from the coaxial rotating processing unit 100.

[0045] The clarified liquid phase located in the radial middle section flows in the direction of the rotation center axis toward the middle section annular overflow weir 160, and overflows and is discharged after crossing the height of the weir plate;

[0046] Microbubbles generated by the electrochemical process capture fine coal slime to form a low-density gas-solid composite phase. The low-density gas-solid composite phase is enriched in the region of the rotation center axis under the action of centripetal buoyancy and enters the suction port of the light phase suction channel 170. An external negative pressure source extracts the low-density gas-solid composite phase through the light phase suction channel 170, thereby completing the three-phase physical separation and independent discharge of the entire coaxial rotating processing unit 100.

[0047] Furthermore, the above-mentioned treatment method for coal-containing wastewater based on electrocoagulation and centrifugal clarification includes the following steps: Construction of a composite centrifugal separation field: Coal-containing wastewater is pumped in through a central coaxial feed pipe 130, and an annular liquid pool running against the wall is formed between the outer shell anode drum 110 and the inner cathode pusher screw 120 under a preset speed difference, so that high-density solid particles settle and compact against the inner wall of the outer shell anode drum 110;

[0048] Fluid dynamics depassivation and in-situ electrocoagulation: A radial DC electric field is applied through the high-current conductive slip ring assembly 140, and the outer shell anode drum 110 dissolves to generate metal cations, which promotes in-situ nucleation of coal slime; at the same time, the asymmetric flow-guided cutting rib 210 induces local eddies, which guide solid particles to scour and peel off the insulating passivation layer.

[0049] Multi-stage shear flotation and three-phase separation: The bubbles precipitated on the surface of the internal cathode pusher screw 120 are mechanically cut and evolved into discrete microbubble groups. Under the drive of centripetal buoyancy, they capture colloidal particles to form a gas-solid composite light phase. Finally, the outer heavy phase, the middle clear liquid phase and the gas-solid composite light phase are separated and layered in the cavity, and are discharged simultaneously through the heavy phase discharge port 150, the middle annular gap overflow weir 160 and the light phase suction channel 170, respectively.

[0050] Example 2

[0051] See attached document Figure 5-6 Based on Embodiment 1, the multi-field coupling workflow of the coaxial rotation processing unit 100 described above includes:

[0052] The drive motor 180 outputs rotational power to drive the outer shell anode drum 110 and the inner cathode pusher screw 120 to rotate in the same direction. The planetary differential 190 distributes the rotational power output by the drive motor 180 and controls the outer shell anode drum 110 and the inner cathode pusher screw 120 to maintain a preset speed difference.

[0053] Coal-containing wastewater is pumped into the coaxial rotary treatment unit 100 through the central coaxial feed pipe 130. The coal-containing wastewater passes through the radial distribution hole of the central coaxial feed pipe 130 and enters the annular treatment area formed between the internal cathode pusher screw 120 and the outer anode drum 110. The external DC power supply continuously supplies power to the outer anode drum 110 through the high current conductive slip ring assembly 140 to form the positive electrode, and continuously supplies power to the internal cathode pusher screw 120 to form the negative electrode.

[0054] Within the annular treatment zone, the coal-containing wastewater is constrained by centrifugal force and adheres to the inner wall of the outer anode drum 110 to form an annular liquid pool. The coal-containing wastewater serves as the electrolyte conductive medium to close the circuit. A radial DC electric field is formed between the outer anode drum 110 and the inner cathode pusher screw 120, penetrating the annular liquid pool. The coaxial rotating treatment unit 100 constructs a physical overlap space between the centrifugal force field and the radial DC electric field within the annular treatment zone.

[0055] Heavy phase particles in coal-containing wastewater settle and accumulate on the inner wall of the outer anode drum 110 under centrifugal force. Due to the preset speed difference between the outer anode drum 110 and the inner cathode pusher screw 120, the fluid in the annular liquid pool and the accumulated heavy phase particles are agitated by the inner cathode pusher screw 120. The heavy phase particles and the inner wall of the outer anode drum 110 undergo relative sliding and scouring. The physical scouring action peels off the passivation layer generated on the inner wall of the outer anode drum 110. Under the action of the radial DC electric field, the outer anode drum 110 undergoes metal oxidation and dissolution, continuously releasing metal cations into the annular liquid pool.

[0056] Under centrifugal compaction, metal cations undergo hydrolysis and polymerization reactions with enriched heavy phase particles. The hydrolysis and polymerization reactions generate polynuclear hydroxy complexes, which promote in-situ nucleation of fine-particle solid materials and produce flocculation and entrapment, thereby forming heavy phase solids. The spiral blades of the internal cathode pusher screw 120 generate axial thrust, pushing the heavy phase solids axially to the heavy phase discharge port 150 and discharging them from the coaxial rotating processing unit 100.

[0057] The internal cathode pusher screw 120 undergoes a reduction reaction under the action of a radial DC electric field to generate hydrogen microbubbles. The hydrogen microbubbles are subjected to centripetal buoyancy in the centrifugal force field and move in the opposite direction to the rotation center axis of the coaxial rotating processing unit 100. During the movement, the hydrogen microbubbles adhere to the surface of colloidal particles in the coal-containing wastewater and combine to form a gas-solid composite light phase.

[0058] Under the centripetal buoyancy drive, the gas-solid composite light phase is gathered to the central area of ​​the internal cathode pusher screw 120. The external vacuum pump 200 establishes negative pressure and continuously extracts the gas-solid composite light phase from the coaxial rotating processing unit 100 through the light phase suction channel 170.

[0059] The remaining liquid phase after separation of heavy phase solids and gas-solid composite light phase is clarified. The clarified liquid phase flows along the axis of rotation to the overflow weir 160 in the middle section annular gap, overflows across the weir plate and is discharged from the coaxial rotating processing unit 100, thus completing the three-phase separation inside the coaxial rotating processing unit 100.

[0060] Example 3

[0061] See attached document Figure 3-4Based on Embodiment 1, multiple asymmetric flow-guiding cutting ribs 210 are arranged axially along the inner wall surface of the outer shell anode drum 110. The asymmetric flow-guiding cutting ribs 210 and the inner sacrificial bushing of the outer shell anode drum 110 are integrally formed. The material of the asymmetric flow-guiding cutting ribs 210 is the same soluble sacrificial metal as the inner sacrificial bushing. The multiple asymmetric flow-guiding cutting ribs 210 are distributed in a spiral array on the inner wall surface of the inner sacrificial bushing. The helix angle parameter of the asymmetric flow-guiding cutting ribs 210 matches the helix angle parameter of the internal cathode pusher spiral 120.

[0062] The cross-section of the asymmetric flow-guiding cutting rib 210 has an asymmetric geometric profile. The profile surface of the asymmetric flow-guiding cutting rib 210 is composed of a gentle slope surface 211 facing the flow and a steep cutting surface 212 facing the flow. The angle between the gentle slope surface 211 facing the flow and the tangent of the inner wall surface of the outer shell anode drum 110 is set between 10 degrees and 30 degrees, forming a fluid transition guiding area. The angle between the steep cutting surface 212 facing the flow and the tangent of the inner wall surface of the outer shell anode drum 110 is set between 75 degrees and 90 degrees, forming a sudden change cross-section area.

[0063] When the coal-containing wastewater flows through the inner wall of the outer anode drum 110, the speed difference between the inner cathode pusher screw 120 and the outer anode drum 110 drives the fluid to climb upward along the upstream gentle slope 211. The structure of the upstream gentle slope 211 guides the fluid to accelerate and maintain the fluid layer in a state of adhering to the wall. When the fluid crosses the top boundary of the asymmetric flow guiding cutting rib 210 and enters the back flow steep cutting surface 212 region, the flow channel cross section changes abruptly. The abrupt change in the flow channel cross section causes the fluid boundary layer to separate. The fluid boundary layer separation induces local eddies in the region behind the back flow steep cutting surface 212.

[0064] Centrifugal force pushes heavy solid particles in coal-containing wastewater toward the inner wall of the outer anode drum 110. Local eddies carry the heavy solid particles enriched around the asymmetric flow-guiding cutting ribs 210, forming a mixed two-phase flow. The mixed two-phase flow generates fluid excitation in the eddy center region. Under the action of fluid excitation, the heavy solid particles gain local kinetic energy, resulting in physical scouring and mechanical cutting of the inner wall of the outer anode drum 110 and the steep backflow cutting surface 212. The mixed two-phase flow generates wall shear stress on the surface deposits. Represented as:

[0065]

[0066] In the formula: This represents the wall shear stress exerted by the mixed two-phase flow on the surface attachments. This represents the local friction coefficient between the mixed two-phase flow and the surface deposits; This represents the local fluid density in a mixed two-phase flow. This represents the relative slip velocity of the mixed two-phase flow relative to the inner wall surface of the outer shell anode drum 110;

[0067] Wall shear stress Overcoming surface adhesion, physical scouring and mechanical cutting continuously peel off the insulating passivation layer generated by electrochemical reaction on the inner wall of the outer shell anode drum 110 and the surface of the asymmetric flow-guiding cutting rib 210. The shedding of the insulating passivation layer leaves the unoxidized metal base layer exposed on the surface of the asymmetric flow-guiding cutting rib 210, maintaining the interface area for the anode metal dissolution reaction. Fluid excitation destroys the ion concentration boundary layer near the steep cutting surface 212, accelerating the diffusion process of metal cations into the main liquid phase of coal-containing wastewater.

[0068] Furthermore, the asymmetric flow-guiding and cutting ribs 210 arranged on the inner wall of the outer shell anode drum 110 change the physical morphology of the fluid boundary layer of the coal-containing wastewater.

[0069] The speed difference between the internal cathode pusher screw 120 and the outer anode drum 110 forces the coal-containing wastewater to slide relative to the inner wall of the outer anode drum 110. During the relative sliding motion, the coal-containing wastewater sweeps over the flow-facing guide surface 211 of the asymmetric flow-facing cutting rib 210. The flow-facing guide surface 211 shrinks the flow channel cross-sectional area, forcing the coal-containing wastewater to increase its flow velocity and maintain the flow layer's wall-attached motion state.

[0070] Coal-containing wastewater crosses the apex of the asymmetric flow-guiding cutting rib 210 and enters the region behind the backflow cutting surface 212. The cross-sectional area of ​​the flow channel suddenly expands in the region behind the backflow cutting surface 212. This sudden expansion causes the fluid boundary layer of the coal-containing wastewater to separate. The separation of the fluid boundary layer forms a negative pressure wake region at the trailing edge of the backflow cutting surface 212. The coal-containing wastewater is entrained in the negative pressure wake region, which in turn forms a local vortex.

[0071] The turbulent kinetic energy intensity of the local eddy is determined by the speed difference parameter between the internal cathode pusher screw 120 and the outer anode drum 110. The external control system controls the turbulent kinetic energy intensity of the local eddy by adjusting the speed difference between the internal cathode pusher screw 120 and the outer anode drum 110.

[0072] Centrifugal force forces the heavy phase solid particles in the coal-containing wastewater to settle towards the inner wall of the outer shell anode drum 110. The local eddy current entrains and enriches the heavy phase solid particles near the inner wall of the outer shell anode drum 110, forming a two-phase mixed abrasive flow of solid and liquid. The heavy phase solid particles acquire transfer kinetic energy that matches the turbulent kinetic energy of the fluid in the rotational motion of the local eddy current.

[0073] Heavy phase solid particles carrying kinetic energy move with local eddies, causing physical impacts and mechanical scouring on the inner wall of the outer shell anode drum 110 and the surface of the asymmetric flow-guiding cutting rib 210. The fluid shear force generated by the mechanical scouring directly acts on the oxides and dirt attached to the surface of the outer shell anode drum 110.

[0074] When the external control system adjusts the speed difference so that the fluid shear force generated by mechanical scouring exceeds the interfacial bonding force between the attached material and the metal substrate of the outer shell anode drum 110, the attached material undergoes micro-fracture and falls off. Physical impact and mechanical scouring continuously peel off the insulating passivation layer generated by electrochemical reaction on the surface of the outer shell anode drum 110. The debris of the insulating passivation layer detaches from the surface of the outer shell anode drum 110 and mixes into the main flow field of coal-containing wastewater.

[0075] The process of stripping the insulating passivation layer allows the unoxidized metal substrate of the outer shell anode drum 110 to be continuously exposed to the coal-containing wastewater. The continuous exposure of the unoxidized metal substrate ensures the effective anode contact area required for the electrochemical dissolution reaction and maintains the stable release process of polynuclear hydroxyl complexes inside the coal-containing wastewater environmental washing and separation equipment.

[0076] Furthermore, the centrifugal compaction reaction zone 310 located between the outer shell anode drum 110 and the inner cathode pusher screw 120 constitutes the physical space for the sedimentation and enrichment of solid particles in coal-containing wastewater as well as electrochemical in-situ flocculation.

[0077] After the coal-containing wastewater enters the centrifugal compaction reaction zone 310, the heavy phase solid particles in the coal-containing wastewater are subjected to centrifugal force and undergo radial sedimentation towards the inner wall surface of the outer shell anode drum 110. The heavy phase solid particles accumulate at the inner wall surface of the outer shell anode drum 110, forming a wall-attached heavy phase coal slime compaction layer 320.

[0078] During the operation of the complete set of environmental washing and separation equipment for coal-containing wastewater, the heavy phase coal slime compacted layer 320 continuously endures centrifugal compaction. The centrifugal compaction forces the physical gap between the heavy phase solid particles to shrink, displacing the free water phase medium existing in the particle pores. The solid phase concentration inside the heavy phase coal slime compacted layer 320 increases with the continuous centrifugal compaction.

[0079] With the unoxidized metal base layer on the inner wall of the outer anode drum 110 in an exposed state, the outer anode drum 110 undergoes continuous electrochemical dissolution in the centrifugal compaction reaction zone 310. The metal cations released by the outer anode drum 110 are in the radial DC electric field constructed between the outer anode drum 110 and the inner cathode pusher screw 120. The radial DC electric field provides electric force to the metal cations. The electric force drives the metal cations to overcome the resistance of the free aqueous phase medium to be squeezed outward and to electromigrate into the interior of the heavy phase coal slime compaction layer 320. The electromigration drives the metal cations to penetrate and enter the interior of the heavy phase coal slime compaction layer 320, completing the directional release process of the metal cations.

[0080] Metal cations undergo hydrolysis and polymerization reactions with water molecules inside the pores of the heavy phase coal slime compacted layer 320. The hydrolysis and polymerization reactions generate polynuclear hydroxy complexes. The polynuclear hydroxy complexes directly contact the surface of the heavy phase solid particles under high pressure and compaction. The heavy phase solid particles simultaneously complete the in-situ nucleation and netting bridging process in the pressure environment of the heavy phase coal slime compacted layer 320.

[0081] The in-situ nucleation and net-catching bridging process combines the discretely distributed heavy phase solid particles into a solid whole. The combination process occurs inside the heavy phase coal slime compaction layer 320, which isolates the shear damage to the primary flocculated structure caused by the main flow field.

[0082] The spiral blades of the internal cathode pusher screw 120 cut into the compacted heavy phase coal slime layer 320. The internal cathode pusher screw 120, through mechanical thrust, peels off the compacted heavy phase coal slime layer 320, which has completed in-situ flocculation, along the axial direction and continuously conveys it to the heavy phase discharge port 150 of the coal-containing wastewater environmental washing and separation equipment.

[0083] Furthermore, the heavy phase coal slime compaction layer 320 located on the inner wall of the outer shell anode drum 110 constitutes the intersection area of ​​in-situ nucleation and physical compaction.

[0084] Electromigration drives polynuclear hydroxy complexes into the interior of the heavy phase coal slime compaction layer 320. The polynuclear hydroxy complexes come into contact with the heavy phase solid particles in the confined pores of the heavy phase coal slime compaction layer 320. The polynuclear hydroxy complexes reduce the repulsion energy barrier on the surface of the heavy phase solid particles through adsorption charge neutralization and netting bridging.

[0085] Heavy phase solid particles undergo in-situ nucleation under the effects of adsorption charge neutralization and netting bridging. The in-situ nucleation process combines the heavy phase solid particles to form a floc skeleton. The floc skeleton is subjected to radial centrifugal pressure generated by the rotation of the outer shell anode drum 110 in the centrifugal compaction reaction zone 310.

[0086] Radial centrifugal pressure compacts the floc skeleton. When the radial centrifugal pressure is greater than the capillary force generated by the microporous capillaries inside the floc skeleton, the compaction causes the heavy phase solid particles to undergo relative displacement and rearrangement inside the heavy phase coal slime compaction layer 320. The rearrangement process reduces the spatial spacing between the heavy phase solid particles and squeezes out the free water existing inside the floc skeleton towards the direction of the rotation center axis.

[0087] After the free water is squeezed out, the heavy phase coal slime compacted layer 320 is consolidated under the constraint of radial centrifugal pressure and net bridging to form a high-density mud cake 410. The internal structure porosity of the high-density mud cake 410 is in a compressed state. The consolidation process occurs on the inner wall of the outer shell anode drum 110, away from the central main fluid channel, so as to avoid the fluid movement of the main liquid phase from damaging the structural integrity of the high-density mud cake 410.

[0088] There is a speed difference between the internal cathode pusher screw 120 and the outer anode drum 110. The speed difference drives the spiral blades of the internal cathode pusher screw 120 to continuously cut into the high-density mud cake 410. The spiral blades generate an axial thrust parallel to the rotation center axis.

[0089] The axial thrust overcomes the frictional resistance between the high-density mud cake 410 and the inner wall of the outer anode drum 110. The internal cathode pusher screw 120 conveys the high-density mud cake 410 along the inner wall of the outer anode drum 110 to the heavy phase discharge port 150. The high-density mud cake 410 is discharged from the heavy phase discharge port 150 into the coal-containing wastewater environmental washing and separation equipment.

[0090] Furthermore, a gradient microbubble rectifier plate 510 is embedded on the spiral blade body of the internal cathode pusher spiral 120. The spiral blade body of the internal cathode pusher spiral 120 has multiple fluid penetration windows along the radial and axial directions. The gradient microbubble rectifier plate 510 is fixedly installed inside the fluid penetration windows. The substrate of the gradient microbubble rectifier plate 510 is formed of an insulating and wear-resistant material.

[0091] A cathode conductive mesh 520 is attached to the back flow side surface of the gradient microbubble rectifier plate 510. The cathode conductive mesh 520 is connected to the negative terminal of the high current conductive slip ring assembly 140. The internal cathode pusher screw 120 has a hollow tubular hub. The inner cavity of the tubular hub is connected to the fluid through window. Coal-containing wastewater enters the back flow side space of the gradient microbubble rectifier plate 510 through the inner cavity of the tubular hub and immerses the cathode conductive mesh 520.

[0092] The gradient microbubble rectifier plate 510 has rectifier microholes 511 arranged on its surface array, which penetrate the thickness direction of the plate. The aperture size of the rectifier microholes 511 is gradually distributed from small to large along the discharge axis of the internal cathode pusher screw 120. The feed end of the internal cathode pusher screw 120 is provided with the rectifier microholes 511 with the smallest aperture size, and the discharge end of the internal cathode pusher screw 120 is provided with the rectifier microholes 511 with the largest aperture size.

[0093] Coal-containing wastewater serves as an electrolyte environment. Under the action of a radial DC electric field, the cathode conductive mesh 520 undergoes an electrochemical reduction reaction. Water molecules gain electrons on the surface of the metal wire mesh of the cathode conductive mesh 520 and release hydrogen gas. The released hydrogen gas gathers at the mesh structure of the cathode conductive mesh 520 to form initial bubbles.

[0094] The initial bubble is subjected to the pressure difference of the flow field and the radial centrifugal force field, and passes through the rectification micro-hole 511 of the gradient microbubble rectifier plate 510. When the initial bubble overflows from the rectification micro-hole 511 and contacts the main processing flow field, the speed difference between the internal cathode pusher screw 120 and the outer shell anode drum 110 applies mechanical shear force to the surface of the overflowing initial bubble.

[0095] The speed difference creates a localized fluid shear rate on the upstream side surface of the gradient microbubble rectifier 510. The computational model is expressed as follows:

[0096]

[0097] In the formula: This represents the local fluid shear rate on the upstream side surface of the gradient microbubble rectifier plate 510; The radius of gyration indicates the location of the gradient microbubble rectifier plate 510; This indicates the rotational angular velocity of the outer casing anode drum 110; This indicates the rotational angular velocity of the internal cathode feed screw 120; This indicates the thickness of the fluid shear boundary layer on the surface of the gradient microbubble rectifier plate 510;

[0098] The local fluid shear rate generates tangential fluid drag at the fluid interface. The tangential fluid drag overcomes the surface tension of the initial bubble at the edge of the rectifying micro-hole 511. The initial bubble is forcibly mechanically cut off at the outlet of the rectifying micro-hole 511, thus forming a discrete microbubble cluster.

[0099] The axial gradient distribution of the rectifier micropore 511 aperture size adjusts the initial volume size of the overflowing bubbles. The aperture size gradient is superimposed with the local fluid shear rate of axial variation, generating discrete microbubble groups with differentiated particle size characteristics in different physical sections of the environmental washing and separation equipment for coal-containing wastewater. The discrete microbubble groups in different sections provide an air flotation contact interface for low-density colloidal particles of different sizes in coal-containing wastewater, constructing the physical conditions for air flotation separation inside the coaxial rotating treatment unit 100.

[0100] Furthermore, in the centrifugal force field of the coaxial rotating processing unit 100, there is a density difference between the discrete microbubble cluster and the main liquid phase of the coal-containing wastewater. Based on the density difference between the discrete microbubble cluster and the main liquid phase of the coal-containing wastewater, the centrifugal force field generates a centripetal buoyancy force on the discrete microbubble cluster pointing towards the rotation center axis of the outer shell anode drum 110.

[0101] Centripetal buoyancy experienced by discrete microbubble clusters inside the coaxial rotating processing unit 100 The computational model is expressed as follows:

[0102]

[0103] In the formula: This represents the centripetal buoyancy force experienced by a single bubble in a discrete microbubble swarm. This indicates the density of the bulk liquid phase of coal-containing wastewater; This indicates the density of the gas inside a single bubble; Indicates the volume of a single bubble; This indicates the rotational angular velocity of the outer casing anode drum 110; The radius of gyration indicating the location of the single bubble;

[0104] Since the density of the main liquid phase of the coal-containing wastewater is greater than the density of the gas inside the individual bubbles, the discrete microbubble swarm overcomes the fluid drag force and moves in the opposite direction to the rotation center axis of the outer shell anode drum 110 under the drive of centripetal buoyancy. The discrete microbubble swarm penetrates the coal-containing wastewater liquid layer in the centripetal movement path.

[0105] Coal-containing wastewater contains fine colloidal particles that have not undergone centrifugal sedimentation. When discrete microbubble clusters penetrate the liquid layer of coal-containing wastewater, they collide with the fine colloidal particles. The discrete microbubble clusters capture the fine colloidal particles by relying on the surface tension of the gas-liquid interface and combine to form a gas-solid composite light phase.

[0106] Under the continuous centripetal buoyancy, the gas-solid composite light phase continues to converge towards the rotation center axis of the outer shell anode drum 110, and the fluid system inside the coaxial rotating processing unit 100 completes the three-phase physical stratification in radial space.

[0107] The three-phase physical stratification includes an outer heavy phase, a middle liquid phase and an axial light phase. The outer heavy phase is composed of a high-density mud cake 410 attached to the inner wall of the outer anode drum 110. The inner cathode pusher screw 120 directionally conveys the high-density mud cake 410 to the heavy phase discharge port 150 and discharges it from the coaxial rotating processing unit 100.

[0108] The intermediate liquid phase is the clarified liquid phase after removing the high-density mud cake 410 and the gas-solid composite light phase. The clarified liquid phase flows to the intermediate annular overflow weir 160 in a direction parallel to the axis of rotation. The clarified liquid phase crosses the height of the weir plate of the intermediate annular overflow weir 160 and overflows out of the coaxial rotating treatment unit 100.

[0109] The axial light phase is composed of a gas-solid composite light phase gathered in the region of the rotation center axis. The hollow tubular hub of the internal cathode pusher screw 120 has a light phase suction channel 170 arranged coaxially. The external vacuum pump 200 applies suction negative pressure to the axial light phase through the light phase suction channel 170.

[0110] The negative pressure suction continuously extracts the gas-solid composite light phase through the light phase suction channel 170 and the coaxial rotating processing unit 100. The outer heavy phase, the middle liquid phase and the axial light phase are output through independent discharge channels, completing the synchronous three-phase separation process of the complete set of coal-containing wastewater environmental washing and separation equipment in the same structural cavity.

Claims

1. A coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification, characterized in that, Includes a coaxial rotation processing unit (100), the coaxial rotation processing unit (100) comprising: The outer shell anode drum (110) constitutes the external pressure-bearing boundary and main body rotation support structure of the coaxial rotating processing unit (100). The main body of the outer shell anode drum (110) is made of soluble metal material, and both ends are supported on the external base by bearing groups. The internal cathode pusher screw (120) is coaxially nested in the inner cavity of the outer shell anode drum (110), and has a hollow tubular hub and a spiral blade fixed to the outer surface of the hollow tubular hub. A preset radial operating gap is maintained between the outer edge of the spiral blade and the inner wall surface of the outer shell anode drum (110). A central coaxial feed pipe (130) extends into the hollow tubular hub of the internal cathode pusher screw (120) along the rotation center axis of the outer shell anode drum (110). The pipe wall is provided with radial feeding holes that connect the internal flow channel with the annular processing area inside the outer shell anode drum (110). A high-current conductive slip ring assembly (140) is sleeved on the drive shaft end of the outer shell anode drum (110). The positive electrode brush terminal included in the high-current conductive slip ring assembly (140) is conductively connected to the outer shell anode drum (110). The negative electrode brush terminal passes through the insulating sealing isolation ring disposed between the outer shell anode drum (110) and the inner cathode pusher screw (120) and is conductively connected to the inner cathode pusher screw (120). The insulating sealing isolation ring blocks the physical contact and current short-circuit path between the two. A drive motor (180) and a planetary differential (190) are provided. The drive motor (180) outputs rotational power and distributes the speed through the planetary differential (190) to keep the outer anode drum (110) and the inner cathode pusher screw (120) rotating in the same direction and maintain a constant speed difference. One end of the coaxial rotating processing unit (100) is provided with a heavy phase discharge port (150), and the other end is provided with a middle section annular gap overflow weir (160). The hollow tubular hub of the internal cathode pusher screw (120) is coaxially arranged with a light phase suction channel (170). The inner wall of the outer anode drum (110) is provided with a plurality of asymmetric flow-guiding and cutting ribs (210) extending axially. The asymmetric flow-guiding and cutting ribs (210) are made of the same soluble metal material as the outer anode drum (110) and are integrally formed. They are used to guide the heavy phase solid particles in the annular processing zone between the outer anode drum (110) and the inner cathode pusher screw (120) to generate local eddies under the speed difference, so as to scour and mechanically cut the insulating passivation layer generated on the inner wall of the outer anode drum (110).

2. The coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification as described in claim 1, characterized in that: Coal-containing wastewater enters the annular treatment zone between the internal cathode pusher screw (120) and the outer anode drum (110) through the radial feeding hole. Under the action of centrifugal inertial force field, it forms an annular liquid pool that runs along the inner wall. After the high current conductive slip ring assembly (140) is connected to the DC power supply, a radial DC electric field is constructed between the two to penetrate the liquid layer of the annular liquid pool, so as to simultaneously load the centrifugal separation field and the electrochemical reaction field.

3. The coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification as described in claim 1, characterized in that: The inner wall of the outer shell anode drum (110) is axially extended with a plurality of asymmetric flow-guiding and cutting ribs (210), which are distributed in a spiral array and whose spiral angle parameters match the spiral angle parameters of the inner cathode pusher spiral (120). The cross-section of the asymmetric flow-guiding cutting rib (210) has an asymmetric geometric profile, and its profile surface is composed of a gentle slope surface (211) facing the flow and a steep cutting surface (212) facing the flow. The angle between the gentle slope surface (211) facing the flow and the tangent of the inner wall surface of the outer shell anode drum (110) is set between 10 degrees and 30 degrees, and the angle between the steep cutting surface (212) facing the flow and the tangent of the inner wall surface of the outer shell anode drum (110) is set between 75 degrees and 90 degrees.

4. The coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification as described in claim 3, characterized in that: When the fluid passes over the asymmetric flow-guiding cutting rib (210) and enters the region of the steep backflow cutting surface (212), local eddies are induced. These local eddies carry heavy phase solid particles to form a mixed two-phase flow and generate fluid excitation. The mixed two-phase flow generates wall shear stress on the surface deposits. Represented as: In the formula: This represents the wall shear stress exerted by the mixed two-phase flow on the surface attachments. This represents the local friction coefficient between the mixed two-phase flow and the surface deposits; This represents the local fluid density in a mixed two-phase flow. This represents the relative slip velocity of the mixed two-phase flow relative to the inner wall surface of the outer shell anode drum (110); Wall shear stress While overcoming surface adhesion, physical scouring and mechanical cutting continuously peel off the insulating passivation layer generated by electrochemical reaction on the inner wall of the outer shell anode drum (110).

5. The coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification as described in claim 1, characterized in that: A centrifugal compaction reaction zone (310) is formed between the outer shell anode drum (110) and the inner cathode pusher screw (120). The radial gap formed between the inner wall of the outer shell anode drum (110) and the inner cathode pusher screw (120) constitutes a physical space for accommodating the settling of heavy phase solid particles. The high current conductive slip ring assembly (140) is configured to provide a radial DC electric field to drive the metal cations released by the outer shell anode drum (110) to undergo electromigration into the interior of the wall-mounted heavy phase coal slime compaction layer (320).

6. The coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification as described in claim 5, characterized in that: Metal cations hydrolyze within the pores of the compacted heavy phase coal slime layer (320) to generate polynuclear hydroxy complexes, which promote in-situ nucleation of heavy phase solid particles to form a floc skeleton. When the radial centrifugal pressure is greater than the capillary force generated by the microporous capillaries inside the floc skeleton, free water is squeezed out towards the axis of rotation, and the compacted heavy phase coal slime layer (320) solidifies to form a high-density mud cake (410), which is then pushed to the heavy phase discharge port (150) by the internal cathode pusher screw (120) for discharge.

7. The coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification as described in claim 1, characterized in that: The internal cathode pusher screw (120) has a gradient microbubble rectifier plate (510) embedded on its spiral blade body. The substrate of the gradient microbubble rectifier plate (510) is made of insulating and wear-resistant material. The back flow side surface of the gradient microbubble rectifier plate (510) is attached with a cathode conductive mesh (520) that is connected to the negative electrode brush terminal of the high current conductive slip ring assembly (140). The surface of the gradient microbubble rectifier plate (510) is arrayed with rectifier microholes (511) that penetrate the thickness direction of the plate body. The aperture size of the rectifier microholes (511) is gradually distributed from small to large along the discharge axis.

8. The coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification as described in claim 7, characterized in that: When the initial bubbles precipitated on the surface of the cathode conductive mesh (520) overflow through the rectifier micropores (511), the speed difference creates a local fluid shear rate on the upstream side surface of the gradient microbubble rectifier plate (510). The computational model is expressed as follows: In the formula: This represents the local fluid shear rate on the upstream side surface; The radius of gyration is indicated by the location of the gradient microbubble rectifier plate (510); Indicates the rotational angular velocity of the outer casing anode drum (110); This indicates the rotational angular velocity of the internal cathode feed screw (120); The thickness of the fluid shear boundary layer on the surface of the gradient microbubble rectifier plate (510) is indicated. The local fluid shear rate generates tangential fluid drag force to mechanically cut the initial bubble, generating a discrete microbubble cluster with differentiated particle size characteristics.

9. The coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification as described in claim 1, characterized in that: In the centrifugal force field, the density difference between the discrete microbubble group and the main liquid phase of the coal-containing wastewater generates a centripetal buoyancy pointing towards the rotation center axis of the outer shell anode drum (110); the discrete microbubble group captures unsettled fine colloidal particles by relying on surface tension in the centripetal motion path, combines to form a gas-solid composite light phase and enriches in the region of the rotation center axis.

10. The coal-containing wastewater treatment system based on electrocoagulation and centrifugal clarification as described in claim 9, characterized in that: The fluid system inside the coaxial rotating processing unit (100) completes three-phase physical stratification in radial space, wherein the outer heavy phase is transported by the internal cathode pusher screw (120) to the heavy phase discharge port (150) and discharged. The clarified liquid phase in the middle section overflows and is discharged across the overflow weir (160) in the middle section annular gap; the gas-solid composite light phase that gathers in the axial region is continuously extracted by an external vacuum pump (200) through the light phase suction channel (170) by applying suction negative pressure, thereby realizing the synchronous three-phase separation process in the same structural cavity.

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