A magnetic seed recovery system and method for a magnetic coagulation clarification apparatus

Abstract

The application discloses a magnetic seed recovery system and method suitable for a magnetic coagulation clarification device. The sludge stirring pump is used to repeatedly circulate the sludge in the sludge storage tank to the sludge solid separation of the magnetic separator, so that the magnetic seed particles are separated and recovered in the magnetic separator for multiple times, and the recovery rate of the magnetic seed particles is greatly improved. Meanwhile, the sludge shearing machine and the magnetic separator are arranged on the top of the sludge storage tank, and the redesigned magnetic seed particle collecting, recovering and secondary adding system is used, so that the limitation caused by the non-pressure magnetic seed particles and sludge after the separation of the magnetic separator on the installation position of the magnetic separator and the equipment height of the sludge storage tank can be overcome, the installation area of the magnetic separator and the sludge storage tank is saved. Finally, the first magnetic seed collecting box and the second magnetic seed collecting box are arranged to realize the long-distance pressure conveying of the magnetic seed particles from the top of the sludge storage tank to the magnetic coagulation clarification device.

Description

Technical Field

[0001] This application belongs to the field of water treatment technology and relates to a magnetic seed recovery system and method suitable for magnetic coagulation clarification equipment. Background Technology

[0002] Mine drainage water and circulating water discharge are typical high-hardness wastewaters with significant reuse value after treatment. Typically, a dual-alkali softening-coagulation clarification process is used to remove hardness and most suspended solids from the raw water before further treatment. However, in some mine drainage water and circulating water discharge, magnesium hardness constitutes a high proportion of the total hardness. The magnesium hydroxide formed after dual-alkali softening is in the form of flocs or flakes, which are large in volume, light in density, and difficult to settle. To address these characteristics of magnesium hydroxide-containing sludge, magnetically enhanced coagulation clarification technology can be employed. This involves adding heavy magnetic particles or powder to the clarifier. The sludge flocs encapsulate the magnetic seeds, and the downward drag of the magnetic seeds on the sludge increases the settling velocity, thereby increasing the upward flow velocity of the equipment and increasing the water treatment capacity.

[0003] In practical applications of magnetically enhanced coagulation and clarification technology, magnetic separation equipment is typically used to separate the magnetic seed particles from the sludge in the clarifier discharge. After separation, the magnetic seed particles fall into the magnetically enhanced coagulation and clarification equipment for secondary use by gravity. The discharged sludge is then sent to a sludge storage tank (pool) for further dewatering.

[0004] However, existing magnetic separation equipment suffers from low magnetic seed particle recovery rates, with some residual particles being lost during sludge discharge, leading to decreased particle utilization and increased operating costs. Simultaneously, the lost magnetic seed particles pose a significant risk of damage to the filter cloth of subsequent plate and frame filter presses. Furthermore, the sludge processed by the magnetic seed separation equipment is unpressurized. To ensure that the sludge can flow into the sludge storage tank (pool) by gravity while the magnetic seed particles fall into the magnetic seed-enhanced coagulation and clarification equipment, the magnetic seed separation equipment is typically installed on top of the magnetic seed-enhanced coagulation and clarification equipment. Moreover, the top elevation of the sludge storage tank (pool) must be lower than that of the magnetic seed-enhanced coagulation and clarification equipment. Due to these constraints, the height of the sludge storage tank (pool) is strictly limited, resulting in an increased equipment footprint and significantly increasing the construction costs of the supporting equipment for magnetic seed-enhanced coagulation and clarification technology.

[0005] Therefore, it is necessary to develop a magnetic seed recovery system and method suitable for magnetic coagulation and clarification equipment, addressing the operational characteristics of existing magnetic seed separation equipment, such as low recovery rate, unpressurized sludge separation, and the fact that separated magnetic seed particles can only fall into the magnetic seed enhanced coagulation and clarification equipment by gravity. This would achieve the goals of saving the footprint of sludge storage tanks (pools), improving the magnetic seed recovery rate of the system, reducing the consumption of magnetic seed particles, and realizing fully automated operation of the equipment. Summary of the Invention

[0006] The purpose of this application is to solve the problems of low magnetic seed particle recovery rate of existing magnetic seed separation equipment, unpressurized sludge after magnetic seed separation equipment, and magnetic seed particles falling into magnetic seed enhanced coagulation and clarification equipment by gravity. This application provides a magnetic seed recovery system and method suitable for magnetic coagulation and clarification equipment. This application can save the footprint of sludge storage tanks (pools), improve the magnetic seed recovery rate of the system, reduce the consumption of magnetic seed particles, and realize the automated operation of the whole set of equipment.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] In a first aspect, this application provides a magnetic seed recovery system suitable for magnetic coagulation and clarification equipment, comprising:

[0009] The magnetic separator has its inlet connected to the sludge discharged from the magnetic seed enhanced coagulation and clarification equipment and the sludge output from the sludge storage tank via a sludge shear; the sludge discharge port of the magnetic separator is connected to the inlet of the sludge storage tank, and the particle discharge port is connected to the first magnetic seed collection box; the rotation speed of the magnetic separator can be adjusted according to the system operating parameters.

[0010] The first magnetic seed collection box has a flushing nozzle at the top for rinsing the inner wall of the first magnetic seed collection box, and the discharge port at the bottom is connected to the second magnetic seed collection box.

[0011] The second magnetic seed collection box has an outlet at its bottom that is connected to a magnetic seed enhanced coagulation and clarification device to achieve secondary reuse.

[0012] Secondly, this application provides a method for recovering magnetic seeds suitable for magnetic coagulation and clarification equipment, comprising the following steps:

[0013] Separation of S1 magnetic seed particles from sludge:

[0014] The sludge discharged from the magnetic seed enhanced coagulation and clarification equipment sequentially enters the sludge shear and magnetic separator to achieve the initial separation and recovery of magnetic seed particles in the discharged sludge. The separated sludge enters the sludge storage tank and is then circulated back into the sludge shear and magnetic separator by the action of the sludge circulation pump to achieve repeated separation and recovery of the magnetic seed particles. The magnetic seed particle slurry obtained after separation slides into the first magnetic seed collection box through the particle discharge port of the magnetic separator and the magnetic seed particle collection tank. The operating frequency of the magnetic separator is adjusted during operation.

[0015] Collection of S2 magnetic seed particles:

[0016] After separation, the magnetic seed particles enter the first magnetic seed collection tank. When the liquid level in the first magnetic seed collection tank reaches the set liquid level L... MAXAt that time, and the pressure transmitter reading of the second magnetic seed collection box reaches the set negative pressure P. a At that time, the first magnetic seed collection box is emptied and controlled sequentially; the second flushing door is opened and flushing continues. a Time was used to flush the magnetic seed particles accumulated on the inner wall of the first magnetic seed collection tank into the liquid surface; then the first discharge door was opened and the process continued for t seconds. b During this time, the solid-liquid mixture in the first magnetic seed collection box is drawn into the second magnetic seed collection box under negative pressure; the second flushing door and the first discharge door are then closed.

[0017] S3 magnetic seed particle recycling: After the above steps are completed, open the compressor valve to pressurize the second magnetic seed collection box until the pressure reaches the set positive pressure P. b At that time, open the second exhaust door and continue for t c During the process, the solid-liquid mixture in the second magnetic seed collection box is forced into the outlet pipe of the second magnetic seed collection box under the positive pressure inside the tank. Then, it flows back to the magnetic seed enhanced coagulation and clarification equipment for secondary utilization by gravity, airflow, and water flow. The second discharge door is closed, and then the exhaust door is opened to reduce the pressure inside the tank. When the pressure reaches the set negative pressure P, a When necessary, close the exhaust valve.

[0018] Compared with the prior art, this application has the following beneficial effects:

[0019] This invention provides an automated magnetic seed particle separation, collection, and recovery device, which can realize the automated separation, collection, recovery, and secondary addition of magnetic seed particles. This can significantly reduce the labor intensity of the above-mentioned operation and improve the operating efficiency and feasibility of the magnetic seed enhanced coagulation and clarification equipment.

[0020] This invention, by placing a sludge shearing machine and a magnetic separator on top of a sludge storage tank, along with a redesigned magnetic seed particle collection, recovery, and secondary addition system, overcomes the limitations imposed by the lack of pressurization in the magnetic seed particles and sludge after separation, which restricts the installation location of the magnetic separator and the height of the sludge storage tank. The installation of the magnetic separator and sludge storage tank saves space.

[0021] This invention utilizes a two-stage magnetic seed particle recovery device consisting of a first magnetic seed collection box and a second magnetic seed collection box. It employs a design concept of gravity-based primary collection, negative pressure-based secondary collection, and pressurized external delivery. By leveraging the high flow rate of compressed air, it reduces the risk of contamination during the transport of magnetic seed solid particles, thereby enabling pressurized long-distance transport of magnetic seed particles.

[0022] This invention addresses the limitation of the single-pass recovery rate of magnetic separators by utilizing a sludge stirring pump to circulate the sludge in the sludge storage tank, allowing the sludge containing magnetic seed particles to repeatedly enter the magnetic separator for solid-sludge separation. This achieves multiple separation and recovery of magnetic seed particles in the magnetic separator, significantly improving the recovery rate of magnetic seed particles.

[0023] The method of this invention is applicable to magnetic seed enhanced coagulation clarification and turbidity removal systems for water sources such as surface water, circulating water sewage, and mine drainage water. It can effectively save land, improve the recovery efficiency of magnetic seed particles, reduce the risk of clogging in the magnetic seed particle recovery path, and has good economic benefits. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a system diagram of a magnetic seed particle recovery system applicable to a magnetically enhanced coagulation and clarification equipment according to the present invention.

[0026] Figure 2 This is an axonometric view of the magnetic seed particle collection tank of the present invention.

[0027] Wherein: 1-Sludge storage tank, 2-Sludge mixing pump, 3-Sludge mass density meter, 4-Sludge shearing machine, 5-Magnetic separator, 6-First flushing door, 7-First magnetic seed collection box, 8-Second flushing door, 9-Flushing nozzle, 10-First discharge door, 11-Second magnetic seed collection box, 12-Exhaust door, 13-Vacuum pump, 14-Compressed air door, 15-Compressed air tank, 16-Second discharge door, 17-Magnetic seed particle collection tank. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0032] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] The present application will now be described in further detail with reference to the accompanying drawings:

[0035] See Figure 1 This application discloses a magnetic seed particle recovery system suitable for magnetically enhanced coagulation and clarification equipment, which mainly includes a sludge storage tank 1, a sludge stirring pump 2, a sludge mass density meter 3, a sludge shearing machine 4, a magnetic separator 5, a first flushing door 6, a first magnetic seed collection box 7, a second flushing door 8, a flushing nozzle 9, a first discharge door 10, a second magnetic seed collection box 11, an exhaust door 12, a vacuum pump 13, a compressed air door 14, a compressed air tank 15, a second discharge door 16, and a magnetic seed particle collection trough 17.

[0036] The bottom discharge port of sludge storage tank 1 is connected to the inlet of sludge mixing pump 2 via a pipeline. Sludge mixing pump 2 is a wear-resistant screw pump or slurry pump. The outlet of sludge mixing pump 2 is connected to the inlet of sludge density meter 3 via a pipeline. The inlet of sludge shearing machine 4 is connected to the outlet of sludge density meter 3 and the outlet of sludge discharge pump of magnetically enhanced coagulation and clarification equipment via pipelines. The outlet of sludge shearing machine 4 is connected to the inlet of magnetic separator 5 via a pipeline. The inlet of first flushing gate 6 is connected to a pressurized clean water pipeline. The outlet of first flushing gate 6 is connected to the inlet of magnetic separator 5 via a pipeline. The sludge discharge port of magnetic separator 5 is connected to the feed port of sludge storage tank 1 via a pipeline. The particle discharge port of magnetic separator 5 is connected to the first magnetic seed collection box 7 via magnetic seed particle collection tank 17.

[0037] The first magnetic seed collection box 7 is an open container. A rinsing nozzle 9 is located inside the upper part of the first magnetic seed collection box 7. The inlet of the rinsing nozzle 9 is connected to a pressurized clean water pipeline, and the rinsing range of the rinsing nozzle 9 can cover the entire inner wall area of ​​the first magnetic seed collection box 7. The inlet of the first discharge door 10 is connected to the discharge port at the bottom of the first magnetic seed collection box 7 via a pipeline, and the outlet of the first discharge door 10 is connected to the inlet of the second magnetic seed collection box 11 via a pipeline. A level transmitter 7-1 is installed on the side wall of the first magnetic seed collection box 7.

[0038] The second magnetic seed collection box 11 is a pressure-sealed container. The main body interfaces of the second magnetic seed collection box 11 include an inlet, an exhaust port, a pressure port, a discharge port, an upper interface of a level gauge, a lower interface of a level gauge, a pressure transmitter interface, and a safety relief valve interface. A magnetic float level gauge 11-1 is installed on the side wall of the second magnetic seed collection box 11, a safety relief valve 11-2 is installed on the upper part, and a pressure transmitter 11-3 is installed on the top. The inlet of the exhaust valve 12 is connected to the exhaust port of the second magnetic seed collection box 11 via a pipe, and the outlet of the exhaust valve 12 is connected to the vacuum pump 13 via a pipe. The inlet of the pressure valve 14 is connected to the compressed air tank 15 via a pipe, and the outlet of the pressure valve 14 is connected to the pressure port of the second magnetic seed collection box 11 via a pipe. The inlet of the second discharge valve 16 is connected to the discharge port of the second magnetic seed collection box 11 via a pipe, and the outlet of the second discharge valve 16 is connected to the surface of the magnetic seed enhanced coagulation and clarification equipment pool via a pipe. The effective liquid volume of the second magnetic seed collection box 11 should not exceed 60% of the container volume, and should not be less than the effective liquid volume of the first magnetic seed collection box 7. The rated working negative pressure of the vacuum pump 13 should not be less than 200 kPa; the rated working positive pressure of the compressed air tank 15 should not be less than 200 kPa; the first discharge valve 10, the second discharge valve 16, the suction valve 12, and the compression valve 14 should be wear-resistant adjustable ball valves.

[0039] The rotational speed of the magnetic drum inside the magnetic separator 5 can be steplessly adjusted, and its operating speed can be calculated and adjusted using the following formula:

[0040]

[0041] In the formula: f is the operating speed of the magnetic separator, in Hz; Q 循 The sludge mixing pump return flow rate is in m. 3 / h;Q 剩 The flow rate of the residual sludge pump is m. 3 / h;ρ t Real-time reading of sludge density meter, kg / m³ 3 ρ1 is the theoretical density of pure inorganic sludge slurry in the sludge storage tank, kg / m³. 3 ;ρ n Real-time density of circulating sludge in magnetic seed enhanced coagulation and clarification equipment, kg / m³ 3 ; t1 is the current sampling time point, s; t0 is a certain time point before the current sampling time point, s; N is the rated maximum particle separation capacity of the magnetic separator, t / h; α is the correction redundancy coefficient, taken as 1.10-1.30.

[0042] like Figure 2 As shown, the magnetic seed particle collection tank 17 is made of wear-resistant, corrosion-resistant and smooth surface material. The collection tank consists of a bottom plate and two side wings, and the cross section is concave.

[0043] In one feasible embodiment of this application, a method for recovering magnetic seed particles based on the above-described method for magnetically enhanced coagulation and clarification equipment is disclosed, comprising the following steps:

[0044] 1) Separation of magnetic seed particles from sludge: The sludge discharged from the magnetic seed enhanced coagulation and clarification equipment sequentially enters the sludge shearing machine 4 and the magnetic separator 5, achieving the initial separation and recovery of magnetic seed particles in the discharged sludge. The separated sludge enters the sludge storage tank 1, and is then circulated back into the sludge shearing machine 4 and the magnetic separator 5 by the action of the sludge circulation pump 2, achieving repeated separation and recovery of the magnetic seed particles. The magnetic seed particle slurry obtained after separation slides into the first magnetic seed collection box 7 through the particle discharge port of the magnetic separator 5 and the magnetic seed particle collection tank 17. During operation, the operating frequency of the magnetic separator 5 is automatically adjusted by formula (1-1).

[0045] 2) Collection of magnetic seed particles: After separation, the magnetic seed particles continuously enter the first magnetic seed collection tank 7. When the liquid level in the first magnetic seed collection tank 7 reaches the set liquid level L... MAX At that time, and the reading of the pressure transmitter 11-3 of the second magnetic seed collection box reaches the set negative pressure P. a At that time, the first magnetic seed collection box 7 is emptied sequentially. The second flushing door 8 is opened and flushed continuously. a Time is used to flush the magnetic seed particles accumulated on the inner wall of the first magnetic seed collection box 7 into the liquid surface. Then, the first discharge door 10 is opened and continuously flushed for t seconds. bAt that time, the solid-liquid mixture in the first magnetic seed collection box 7 is drawn into the second magnetic seed collection box 11 under negative pressure. The second flushing door 8 and the first discharge door 10 are then closed.

[0046] 3) Recycling of magnetic seed particles: After the above steps are completed, open the compressor valve 14 to pressurize the second magnetic seed collection box 11 until the pressure reaches the set positive pressure P. b At that time, open the second row door 16 and continue for t c During the process, the solid-liquid mixture in the second magnetic seed collection box 11 is forced into the outlet pipe of the second magnetic seed collection box 11 under the positive pressure inside the tank. Then, it flows back to the magnetic seed enhanced coagulation and clarification equipment for secondary utilization under the action of gravity, airflow, and water flow. The second discharge door 16 is closed, and then the exhaust door 12 is opened to reduce the pressure inside the tank. When the pressure reaches the set negative pressure P... a When this happens, close the exhaust valve 12.

[0047] Example:

[0048] The water supplied to a certain factory is high-salinity mine drainage water. It is treated with magnetic seed-enhanced coagulation and clarification equipment for softening and turbidity removal, and is equipped with a magnetic seed particle recovery system. The maximum designed capacity of a single unit is 160 m³ / h. 3 / h, the influent water quality indicators are shown in Table 1 below:

[0049] Table 1. Influent Water Quality Indicators

[0050] <![CDATA[Ca 2+ (mg / L)]]> <![CDATA[Mg 2+ (mg / L)]]> Turbidity (NTU) TDS (mg / L) Total alkalinity (mmol / L) 195 143 ＜10 3700 1.3

[0051] 1) Separation of magnetic seed particles from sludge: When the sludge storage tank reaches its minimum level, the sludge stirring pump, high-speed shear, and magnetic separator are started simultaneously. The stirred sludge and the sludge discharged from the magnetic seed enhanced coagulation and clarification equipment sequentially enter the sludge shear and magnetic separator, achieving multiple cycles of separation and recovery of the magnetic seed particles in the discharged sludge. The magnetic seed particle slurry obtained after separation slides into the first magnetic seed collection box through the magnetic seed particle collection tank via the magnetic separator particle discharge port. During operation, the operating frequency of the magnetic separator is automatically adjusted using formula (1-1). Calculations show that when only sludge stirring is performed, the magnetic separator operating frequency is approximately 15Hz; when sludge stirring and the discharge sludge from the magnetic seed enhanced coagulation and clarification equipment are performed simultaneously, the magnetic separator operating frequency is between 45-50Hz.

[0052] 2) Collection of magnetic seed particles: After separation, the magnetic seed particles continuously enter the first magnetic seed collection tank. When the liquid level in the first magnetic seed collection tank reaches the set high liquid level of 750 mm, and the pressure transmitter reading of the second magnetic seed collection tank reaches the set negative pressure of -70 kPa, the venting control of the first magnetic seed collection tank is activated. The second flushing door is opened and held for 15 seconds to flush the magnetic seed particles accumulated on the inner wall of the first magnetic seed collection tank to the liquid surface. Then, the first discharge door is opened and held for 30 seconds, and the solid-liquid mixture in the first magnetic seed collection tank is drawn into the second magnetic seed collection tank under negative pressure. The second flushing door and the first discharge door are then closed.

[0053] 3) Reuse of magnetic seed particles: After the above steps are completed, open the compressor valve to pressurize the second magnetic seed collection box. When the pressure reaches the set positive pressure of 100 kPa, open the second discharge valve and hold for 30 seconds. The solid-liquid mixture in the second magnetic seed collection box is forced into the outlet pipe of the second magnetic seed collection box under the positive pressure inside the tank. Subsequently, it flows back to the magnetic seed enhanced coagulation and clarification equipment for secondary utilization by gravity, airflow, and water flow. Close the second discharge valve. Then open the exhaust valve to depressurize the tank. When the pressure reaches the set negative pressure of -70 kPa, close the exhaust valve.

[0054] During continuous operation, the system runs well, and the recovery rate of magnetic seed particles can reach over 99%.

[0055] The principle of this application:

[0056] This invention addresses the limitation of limited single-pass recovery rate of magnetic separators by utilizing a sludge stirring pump to circulate sludge in the sludge storage tank. This allows sludge containing magnetic seeds to repeatedly enter the magnetic separator for solid-sludge separation, achieving multiple separation and recovery of magnetic seeds within the separator and significantly improving the recovery rate. Furthermore, by placing the sludge shearing machine and magnetic separator on top of the sludge storage tank, supplemented by a redesigned magnetic seed collection, recovery, and secondary addition system, the limitations imposed by the lack of pressurization of the separated magnetic seeds and sludge on the installation location of the magnetic separator and the height of the sludge storage tank are overcome, resulting in a space-saving installation for both the magnetic separator and the sludge storage tank. Additionally, by incorporating a two-stage magnetic seed collection device (first and second magnetic seed collection boxes), and employing a design concept of gravity-based primary collection, negative-pressure secondary collection, and pressurized delivery, the high-velocity characteristics of compressed air reduce the risk of clogging during transport, enabling pressurized long-distance transport of magnetic seed solid particles. All equipment is automatically controlled, enabling fully automated separation, collection, recovery, and secondary addition of magnetic seed particles. This significantly reduces the labor intensity of the above-mentioned operations and improves the operating efficiency and technical feasibility of the magnetic seed enhanced coagulation and clarification equipment.

[0057] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A magnetic seed recovery system suitable for use in a magnetic coagulation clarification apparatus, characterized in that, The application relates to a magnetic separation device, which comprises the following parts: a magnetic separation machine (5), an inlet of the magnetic separation machine (5) being connected with sludge of a magnetic seed reinforced coagulation and clarification device and sludge output by a sludge shearing machine (4) and an outlet of a sludge storage tank (1); a sludge discharge port of the magnetic separation machine (5) being connected with an inlet of the sludge storage tank (1), a particle discharge port being connected with a first magnetic seed collecting box (7); the rotating speed of the magnetic separation machine (5) can be adjusted according to system operation parameters; a magnetic seed particle collecting groove (17) is arranged below the sludge discharge port of the magnetic separation machine (5), an outlet of the magnetic seed particle collecting groove (17) being arranged at an inlet of the first magnetic seed collecting box (7); a liquid level transmitter (7-1) is arranged on the first magnetic seed collecting box (7), a discharge pipeline being connected with a bottom discharge port, a first discharge door (10) being arranged on the discharge pipeline, an outlet of the first discharge door (10) being connected with an inlet of a second magnetic seed collecting box (11); a sludge stirring pump (2) is connected with the sludge shearing machine (4) through a discharge port at the bottom of the sludge storage tank (1); a sludge mass density meter (3) is arranged on a pipeline between the sludge stirring pump (2) and the sludge shearing machine (4); the sludge stirring pump (2) is a screw pump or a slurry pump; the first discharge door (10), a second discharge door (16), an air suction door (12) and an air compression door (14) are all adjustable ball valves; the first magnetic seed collecting box (7), a flushing nozzle (9) for flushing the inner wall of the first magnetic seed collecting box (7) being arranged above the first magnetic seed collecting box (7), a discharge port at the bottom being connected with the second magnetic seed collecting box (11); the first magnetic seed collecting box (7) is an open container, the liquid level transmitter (7-1) being arranged on a side wall of the first magnetic seed collecting box (7); the second magnetic seed collecting box (11) is a pressure type closed container; the second magnetic seed collecting box (11), a discharge port at the bottom of the second magnetic seed collecting box (11) being connected with the magnetic seed reinforced coagulation and clarification device, realizing secondary utilization of backflow; a liquid level meter (11-1), a pressure relief valve (11-2) and a pressure transmitter (11-3) being arranged on the second magnetic seed collecting box (11); the second magnetic seed collecting box (11) is connected with a vacuum pump (13) through the air suction door (12) and connected with a compressed air tank (15) through the air compression door (14); a discharge port at the bottom of the second magnetic seed collecting box (11) is connected with the magnetic seed reinforced coagulation and clarification device through the second discharge door (16); the liquid level meter (11-1) is a magnetic float liquid level meter, being arranged on a side wall of the second magnetic seed collecting box (11); the pressure relief valve (11-2) is arranged on the upper part of the side wall of the second magnetic seed collecting box (11), and the pressure transmitter (11-3) is arranged on the top of the second magnetic seed collecting box (11).

2. The magnetic seed recovery system suitable for use in a magnetic coagulation clarification apparatus according to claim 1, characterized in that, a first flushing door (6) is connected with the inlet pipeline of the magnetic separation machine (5) and connected with clean water under pressure through the first flushing door (6); the flushing nozzle (9) is connected with clean water under pressure through a second flushing door (8).

3. The magnetic seed recovery system suitable for use in a magnetic coagulation clarification apparatus according to claim 1, wherein, the magnetic seed particle collecting groove (17) comprises a bottom plate and wing guards arranged on both sides of the bottom plate, and the cross section is concave.

4. The magnetic seed recovery system suitable for use with a magnetic coagulation clarification apparatus of claim 1, wherein, The effective liquid volume of the second magnetic seed collecting tank (11) is not more than 60% of the container volume, and is not less than the effective liquid volume of the first magnetic seed collecting tank (7); the rated working negative pressure of the vacuum pump (13) is not less than 200 kPa; and the rated working positive pressure of the compressed air tank (15) is not less than 200 kPa.

Images