A dry discharge dewatering system and method for efficient recovery of fine sand and silt particles using gravity settling

Abstract

The application discloses a dry discharge dehydration system and method for efficiently recycling fine sand and stone powder fine particles by gravity precipitation, which comprises a groove belt type fine sand recycling system and a shower type tail slurry distribution system arranged at the upper portion of the groove belt type fine sand recycling system; the groove belt type fine sand recycling system is divided into a fine sand water control dry discharge section, a fine sand precipitation recycling section and a sewage discharge section along the running direction of the groove belt type fine sand recycling system; the fine sand water control dry discharge section, the fine sand precipitation recycling section and the sewage discharge section are connected into an integrated whole by an annular conveying groove belt; the slurry is in the form of water droplets and does not have impact force by the thickness of at least 3 layers of punching plates, so that the slurry can better complete precipitation and will not scour the precipitation layer; the application utilizes the principle that particles in sewage will be affected by gravity and flow rate to produce precipitation, realizes efficient recycling of fine particles and ultra-fine particles, and solves the technical problem that materials below the sieve hole diameter of a screening device are difficult to recycle.

Description

Technical Field

[0001] This invention relates to the field of mining technology, and in particular to a high-efficiency recovery device for mine tailings, manufactured fine sand, and fine stone powder particles, a solid-liquid separation system, and a treatment method for solid-liquid separation using the system. Background Technology

[0002] Currently, most existing mineral processing and manufactured sand production lines in China use wet production processes. However, existing dry discharge technologies and equipment, regardless of the type of dewatering equipment used, all employ screening structures. This necessitates overcoming liquid surface tension, making it difficult to process screens to apertures <1mm. Consequently, the recovery of -100 mesh fine particles remains a challenge, especially for ultrafine particles such as sand and stone powder (-200 mesh), with loss rates exceeding 20%. The loss of these fine and ultrafine particles not only leads to excessive tailings discharge, environmental pollution, and land occupation, but also directly results in production losses and substandard gradation in the manufactured sand industry, affecting product quality. Furthermore, sand washing machines and high-frequency dewatering screens widely used domestically and internationally for recovering fine sand and stone powder particles suffer from technical drawbacks such as high energy consumption, small processing capacity, low recovery rate, severe screen wear, and high recovery costs. Summary of the Invention

[0003] The purpose of this invention is to provide a method that does not require screening or filtration, but only utilizes the gravity and ultrafine particle suspension characteristics of fine sand (tailings) and stone powder particles in tailings (washing sand) wastewater. Solid-liquid separation is achieved through natural sedimentation in a trough structure, and the settled solid particles are then discharged again under controlled water conditions via a reverse conveying device. This method achieves efficient recovery of fine sand (tailings) and stone powder particles and reduces the cost of fine sand and stone powder recovery.

[0004] The technical solution provided by this invention is: a dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation, comprising a belt-type fine sand recovery system and a spray-type tail slurry distribution system installed on the upper part of the belt-type fine sand recovery system; the belt-type fine sand recovery system is divided into a fine sand water control dry discharge section, a fine sand sedimentation and recovery section, and a sewage discharge section along its running direction, the fine sand water control dry discharge section, the fine sand sedimentation and recovery section, and the sewage discharge section are connected by a ring conveyor belt, the conveyor belt has vertical skirts on both sides of its outer surface, a drive roller and a variable frequency drive motor are provided at the beginning of the fine sand water control dry discharge section, and a reversing tail wheel is provided at the end of the sewage discharge section, the drive roller and the reversing tail wheel are rotatably mounted on an integral support, the integral support is provided with an upper support roller group and a lower support roller group corresponding to the inner side of the conveyor belt, and the integral support is in contact with the ground through a series of adjustable support legs;

[0005] The shower-type tailings slurry distribution system is located at the front end of the fine sand sedimentation and recovery section. The shower-type tailings slurry distribution system includes a square distribution box. The top of the square distribution box is provided with a feed inlet pipe that is inserted into the square distribution box. The feed inlet pipe is perpendicular to the center of the box and injects into the square distribution box. Inside the square distribution box, below the outlet of the feed inlet pipe, there are three layers of perforated horizontal baffles arranged at intervals. The diameter of the perforations on the first, second, and third layers of perforated horizontal baffles decreases sequentially. The bottom of the square distribution box is open, and the top is provided with a fixed top cover and a movable top cover.

[0006] This invention also discloses a method for implementing a dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation, comprising the following steps:

[0007] (1) Tailings wastewater or sand washing wastewater is pumped through a pipeline to the square distribution box of the shower-type tailings slurry distribution system. It is injected into the square distribution box through the feed inlet pipe perpendicular to the center of the square distribution box. After passing through 3 or more layers of perforated horizontal baffles, it becomes a continuous dripping water that falls into the trough-type fine sand recovery system, completing the first step of slurry distribution.

[0008] (2) The spray-shaped slurry falling into the fine sand sedimentation and recovery section near the fine sand water control and dry discharge section flows slowly with the natural drainage slope of the channel. During the flow, larger particles slowly sink under the action of gravity and fall to the bottom of the channel, while fine particles continue to be suspended in the sewage and continue to flow towards the sewage discharge section under the action of water flow. When all the slurry flows through the channel of the fine sand sedimentation and recovery section, the particulate solids in the sand washing sewage or tailings sewage are basically settled, and only the ultrafine particles suspended in the sewage enter the sewage discharge section with the sewage.

[0009] (3) The sewage entering the sewage discharge section begins to flow faster due to the change in the flow slope, which creates a certain scouring force on the channel belt, washing away the fine mud and other attachments adhering to the channel belt and discharging them with the sewage.

[0010] (4) Since the direction of the belt running is opposite to the direction of the sewage flow, the fine sand and stone powder that are settled at the bottom of the belt in the fine sand sedimentation and recovery section are slowly moved towards the end of the fine sand control and dry discharge by the belt and gradually moved out of the water surface. In the belt with a positive upward angle, the saturated water in the sedimentation layer is controlled out while moving, so that the sedimentation layer is gradually dehydrated and forms a fine sand sedimentation layer with a low water content. When the dehydrated fine sand sedimentation layer runs to the drive roller, it is unloaded from the roller along with the belt, thus completing the dehydration and dry discharge process of the ultrafine sand.

[0011] The advantages of this invention compared to the prior art are:

[0012] (1) The present invention has a multi-layer shower-type tail slurry distribution system: In order to eliminate the impact force generated by the tail slurry distribution to the maximum extent, the present invention adopts a three-layer or more perforated plate distribution method. Each time the slurry passes through a perforated plate, its pumping impact force is reduced. After passing through at least three layers of perforated plates, the slurry drips in the form of water droplets and no longer has impact force, so that the slurry can better complete the sedimentation and will not scour the sedimentation layer.

[0013] (2) This invention is the first to propose a screenless fine sand dewatering and recycling theory: utilizing the principle that particulate matter will precipitate in sewage under the influence of gravity and flow velocity, the sewage is passed through a trough structure with a certain slope, so that the particles in the sewage complete the sedimentation under the action of gravity and form a sediment layer. Then, through countercurrent output, the efficient recycling of fine and ultrafine particles is achieved, which solves the technical problem that materials below the screen aperture of screening equipment are difficult to recycle and utilize.

[0014] (3) The present invention adopts a three-section independent support vertical adjustment structure: In order to better adapt to changes in production process parameters such as tailings concentration, particle size, and sewage flow rate, the present invention adopts a three-section independent support vertical adjustment structure, which can adjust the three sections of the support at different angles to meet production needs.

[0015] (4) The present invention adopts a novel reverse trough belt sedimentation structure: the skirted conveyor belt is used as a sedimentation tank structure for the first time. The U-shaped structure of the trough belt is used, with one side raised and the other side lowered, so that it has three functions: sedimentation, dewatering and sewage discharge, which are completed simultaneously on one trough belt.

[0016] (5) The present invention adopts a reverse upward dry discharge structure of the trough belt: Unlike the traditional screening and dewatering dry discharge, by raising one end of the trough belt, the water-laden fine sand layer can be drained from the bottom to complete the dewatering process and realize the dry discharge operation of fine sand and ultrafine sand.

[0017] (6) Because the present invention adopts a three-stage independent adjustment design, the fine sand recovery particle size can be flexibly adjusted by adjusting the drainage slope of the sedimentation section, which breaks the technical defect that screening equipment cannot flexibly change the fineness of the product without adjusting the screen.

[0018] (7) Since the non-screen dry discharge technology is adopted, there is no need to consider the influence of liquid surface tension on the water permeability during the production process. The whole process basically relies on the self-weight and fluidity of the sewage slurry, with no additional energy consumption. Therefore, it saves more than 30% energy compared with other dry discharge methods, and the fine particle recovery rate is increased by more than 15%. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention.

[0020] Figure 2 This is a cross-sectional schematic diagram of the belt-type fine sand recovery system in this invention.

[0021] Figure 3 This is a schematic diagram of the structure of the skirt on the conveyor belt in this invention.

[0022] Figure 4 This is an enlarged schematic diagram of the conveyor belt in this invention.

[0023] Figure 5 This is a schematic diagram of the shower-type tail slurry distribution system in this invention.

[0024] Figure 6 This is a schematic diagram of the three-layer perforated horizontal partition in this invention.

[0025] Figure 7 This is a schematic diagram of the connection between independent support one and independent support two in this invention.

[0026] Figure 8 This is a schematic diagram showing the connection of independent bracket two and independent bracket three in this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] In the description of the embodiments of the present invention, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" 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 the present invention 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 of the present invention. Furthermore, terms such as "first," "second," and "third" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] Furthermore, the use of terms such as "horizontal," "vertical," and "sag" does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0030] In the description of the embodiments of the present invention, "multiple" means at least two.

[0031] In the description of the embodiments of the present invention, 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 the present invention according to the specific circumstances.

[0032] Example:

[0033] Combined with appendix Figure 1-8This embodiment discloses a dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation. It includes a belt-type fine sand recovery system and a spray-type tailings slurry distribution system located above the belt-type fine sand recovery system. The belt-type fine sand recovery system is divided into a fine sand water control dry discharge section A, a fine sand sedimentation and recovery section B, and a wastewater discharge section C along its operating direction. The spray-type tailings slurry distribution system's main function is to eliminate the pumping pressure of tailings wastewater or sand washing wastewater and reduce the scouring force of the feed. The spray-type tailings slurry distribution system is located at the front end of the fine sand sedimentation and recovery section B. The spray-type tailings slurry distribution system includes a square distribution box 1, with a square distribution box 1 topped with a square distribution element for inserting the distribution box. The material inlet pipe 2 inside the box 1 is perpendicular to the center of the box and injects material into the square material box 1. Inside the square material box 1, below the outlet of the material inlet pipe 2, there are three layers of perforated horizontal partitions: a first layer of perforated horizontal partitions 3, a second layer of perforated horizontal partitions 4, and a third layer of perforated horizontal partitions 5. The three layers of perforated horizontal partitions are perforated steel plates or other types of wear-resistant plates horizontally set inside the box. The plates are perforated in a pattern of sparser holes in the center and denser holes around the perimeter. The diameter of the perforations on the first layer of perforated horizontal partitions 3, the second layer of perforated horizontal partitions 4, and the third layer of perforated horizontal partitions 5 decreases sequentially. The bottom of the square material box 1 is open, and the top is equipped with a fixed top cover 6 and a movable top cover 7. The total perforated area on the first-layer perforated horizontal baffle 3 is more than twice the inlet cross-sectional area of ​​the pumping pipe for tailings wastewater or sand washing wastewater. The pumped wastewater passes through the first-layer perforated horizontal baffle 3, where the water pressure is initially eliminated, and the wastewater falls relatively evenly onto the second-layer perforated horizontal baffle 4, which maintains a certain horizontal distance from the first-layer perforated horizontal baffle 3, forming a certain liquid level. The diameter of the perforations in the first-layer perforated horizontal baffle 3 is half the diameter of the upper layer plate. The number of perforations in the second-layer perforated horizontal baffle 4 is 1.5 times the number of perforations in the first-layer perforated horizontal baffle 3, to further eliminate the scouring force of the pumped slurry. The slurry passing through the second-layer perforated horizontal baffle 4 enters the third-layer perforated horizontal baffle. The third layer of perforated horizontal partition 5 maintains a certain distance from the second layer of perforated horizontal partition 4 and is horizontal with the first and second layers of perforated horizontal partition 4. The aperture of the perforated plate of the third layer of perforated horizontal partition 5 is half the aperture of the perforated plate of the second layer of perforated horizontal partition 4, and the number of holes in the third layer of perforated horizontal partition 5 is 1.5 times that of the perforated plate of the second layer of perforated horizontal partition 4. The upper and lower holes of the three layers of perforated horizontal partition 5 should be kept away from being on the same vertical center line as much as possible, and the holes in the three layers of perforated horizontal partition 5 should be alternately set to avoid direct current phenomenon. The slurry diverted by the three layers of perforated horizontal partition 5 falls into the trough belt fine sand recovery system in a continuous dripping manner, completing the first step of slurry distribution.

[0034] In the belt conveyor fine sand recovery system, the fine sand control and dry discharge section A, the fine sand sedimentation and recovery section B, and the wastewater discharge section C are connected by a single annular conveyor belt 8. The conveyor belt 8 has vertically installed skirts 9 on both sides. A drive roller 10 and a variable frequency drive motor are installed at the beginning of the fine sand control and dry discharge section A, serving as the power output device for the entire system. A redirecting tail wheel 11 is installed at the end of the wastewater discharge section C, serving as a redirecting device for the annular conveyor belt 8. The drive roller 10, the variable frequency drive motor, and the redirecting tail wheel 11 are rotatably mounted on the entire system. On the support 12, the overall support 12 is equipped with an upper roller group 13 and a lower roller group 14 corresponding to the inner side of the conveyor belt 8. The overall support 12 is in contact with the ground through a series of adjustable support legs 15. The overall support 12 consists of independent support 1201, independent support 2 1202 and independent support 3 1203 corresponding to the fine sand water control dry discharge section A, the fine sand sedimentation and recovery section B and the sewage discharge section C. The tops of independent support 1201 and independent support 2 1202 are hinged together, and the bottoms of independent support 2 1202 and independent support 3 1203 are hinged together.

[0035] The end of the fine sand control and drainage section A is tilted upwards at an angle of 8 to 12 degrees; the fine sand sedimentation and recovery section B is set with a natural drainage slope, sloping from the fine sand control and drainage section A to the sewage discharge section C at a 1 to 2 degree angle; the end of the sewage discharge section C is tilted downwards at an angle of 3 to 5 degrees; the overall support 12 has at least 5 sets of adjustable support legs 15, of which at least 3 sets of adjustable support legs 15 are used to support the fine sand recovery section support, at least 1 set of adjustable support legs 15 are used to support the end of the fine sand control and drainage section A, and at least 1 set of adjustable support legs 15 are used to support the end of the sewage discharge section C. The adjustable support leg 15 includes an upper support leg 1501 connected to the overall support 12 and a lower support leg 1502 disposed opposite to the upper support leg 1501. The upper support leg 1501 and the lower support leg 1502 are connected by a threaded post 1503. A locking bolt 1504 is provided at the connection between the threaded post 1503 and the upper support leg 1501 and the lower support leg 1502.

[0036] This embodiment also discloses a method for implementing a dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation, including the following steps:

[0037] (1) Tailings wastewater or sand washing wastewater is pumped to the square distribution box 1 of the shower-type tailings slurry distribution system through the pump pipeline. It is injected into the square distribution box 1 through the feed inlet pipe 2 perpendicular to the center of the square distribution box 1. After passing through 3 or more layers of perforated horizontal baffles, it becomes a continuous dripping water that falls into the trough belt fine sand recovery system, completing the first step of slurry distribution.

[0038] (2) The spray-shaped slurry falling on the fine sand sedimentation and recovery section B near the fine sand water control and dry discharge section A flows slowly with the natural drainage slope of the channel. During the flow, larger particles slowly sink under the action of gravity and fall to the bottom of the channel, while fine particles continue to be suspended in the sewage and continue to flow towards the sewage discharge section C under the action of water flow. When all the slurry flows through the channel of the fine sand sedimentation and recovery section B, the particulate solids in the sand washing sewage or tailings sewage are basically settled, and only the ultrafine particles suspended in the sewage enter the sewage discharge section C with the sewage.

[0039] (3) The sewage entering the sewage discharge section C begins to flow faster due to the change in the flow slope, which creates a certain scouring force on the channel belt, washing away the fine mud and other attachments adhering to the channel belt and discharging them with the sewage.

[0040] (4) Since the direction of the belt running is opposite to the direction of the sewage flow, the fine sand and stone powder that are settled at the bottom of the belt in the fine sand sedimentation and recovery section B of the sand washing sewage or tailings sewage are slowly moved towards the end of the fine sand control and dry discharge by the belt and gradually moved out of the water surface. In the belt with a positive upward angle, the saturated water in the sedimentation layer is controlled out while moving, so that the sedimentation layer is gradually dehydrated and forms a fine sand sedimentation layer with a low water content. When the dehydrated fine sand sedimentation layer runs to the drive roller 10, it is unloaded from the roller along with the belt, thus completing the dehydration and dry discharge process of the ultrafine sand.

[0041] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation, characterized in that, The system includes a belt-type fine sand recovery system and a spray-type tail slurry distribution system installed on top of the belt-type fine sand recovery system. The belt-type fine sand recovery system is divided into a fine sand water control and dry discharge section, a fine sand sedimentation and recovery section, and a sewage discharge section along its operating direction. The fine sand water control and dry discharge section, the fine sand sedimentation and recovery section, and the sewage discharge section are connected by a ring-shaped conveyor belt. Skirts are vertically provided on both sides of the outer surface of the conveyor belt. A drive roller and a variable frequency drive motor are provided at the beginning of the fine sand water control and dry discharge section, and a reversing tail wheel is provided at the end of the sewage discharge section. The drive roller and the reversing tail wheel are rotatably mounted on an integral support. The integral support is provided with an upper support roller group and a lower support roller group corresponding to the inner side of the conveyor belt. The integral support is in contact with the ground through a series of adjustable support legs. The fine sand water control dry discharge section is tilted upwards at an angle of 8-12°; the fine sand sedimentation and recovery section is set with a natural drainage slope, sloping from the fine sand water control dry discharge section to the sewage discharge section at a 1-2° angle; the end of the sewage discharge section is tilted downwards at an angle of 3-5°; the running direction of the conveyor belt is opposite to the flow direction of the sewage in the conveyor belt. The shower-type tailings slurry distribution system is located at the front end of the fine sand sedimentation and recovery section. The shower-type tailings slurry distribution system includes a square distribution box. A feed inlet pipe is installed at the top of the square distribution box and inserted into the box. The feed inlet pipe is perpendicular to the center of the box. Tailings wastewater or sand washing wastewater is injected into the box through the feed inlet pipe. Inside the box, below the outlet of the feed inlet pipe, there are three layers of perforated horizontal baffles: a first layer, a second layer, and a third layer. The diameter of the perforations on the first, second, and third layers decreases sequentially. The bottom of the box is open, and the top is equipped with a fixed cover and a movable cover.

2. The dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation as described in claim 1, characterized in that, The overall support frame has at least 5 sets of adjustable support legs, of which at least 3 sets of adjustable support legs are used to support the fine sand sedimentation and recovery section support, at least 1 set of adjustable support legs are used to support the end of the fine sand water control and dry discharge section, and at least 1 set of adjustable support legs are used to support the end of the sewage discharge section.

3. The dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation as described in claim 2, characterized in that, The overall support consists of three independent supports: Independent Support 1, Independent Support 2, and Independent Support 3, which correspond to the fine sand water control and dry discharge section, the fine sand sedimentation and recovery section, and the sewage discharge section. The tops of Independent Support 1 and Independent Support 2 are hinged together, and the bottoms of Independent Support 2 and Independent Support 3 are hinged together.

4. The dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation as described in claim 1, characterized in that, The total area of ​​the perforated horizontal partition in the first layer is more than twice the cross-sectional area of ​​the inlet of the pumping pipeline for tailings wastewater or sand washing wastewater; the diameter of the perforated holes in the second layer of the perforated horizontal partition is half the diameter of the perforated holes in the first layer of the perforated horizontal partition, and the number of holes in the second layer of the perforated horizontal partition is 1.5 times the number of holes in the first layer of the perforated horizontal partition; the diameter of the perforated holes in the third layer of the perforated horizontal partition is half the diameter of the perforated holes in the second layer of the perforated horizontal partition, and the number of holes in the third layer of the perforated horizontal partition is 1.5 times the number of holes in the second layer of the perforated horizontal partition.

5. The dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation as described in claim 4, characterized in that, The perforations on the first layer of perforated horizontal partition, the second layer of perforated horizontal partition, and the third layer of perforated horizontal partition are staggered.

6. The dry discharge dewatering system for efficient recovery of fine sand and stone powder particles using gravity sedimentation as described in claim 1, characterized in that, The adjustable support leg includes an upper support leg connected to the overall support and a lower support foot opposite to the upper support leg. The upper support leg and the lower support foot are connected by a threaded post, and a locking bolt is provided at the connection between the threaded post and the upper support leg and the lower support foot.

7. A dry discharge dewatering method for efficient recovery of fine sand and stone powder particles using gravity sedimentation, characterized in that, The dry discharge dewatering system according to any one of claims 1-6 is implemented by comprising the following steps: (1) Tailings wastewater or sand washing wastewater is pumped to the square distribution box of the shower-type tailings slurry distribution system through a pumping pipeline. The feed inlet pipe is perpendicular to the center of the square distribution box. Tailings wastewater or sand washing wastewater is injected into the square distribution box through the feed inlet pipe, and then passes through 3 layers of perforated horizontal partitions, becoming a continuous dripping water that falls into the trough-type fine sand recovery system, completing the first step of slurry distribution. (2) The spray-shaped slurry falling in the fine sand sedimentation and recovery section near the fine sand water control and dry discharge section flows slowly along the natural drainage slope of the conveyor belt. During the flow, larger particles slowly sink under the action of gravity and fall to the bottom of the conveyor belt, while fine particles continue to be suspended in the sewage and continue to flow towards the sewage discharge section under the action of water flow. When all the slurry flows through the conveyor belt of the fine sand sedimentation and recovery section, the particulate solids in the tailings sewage or sand washing sewage are basically settled, and only the ultrafine particles suspended in the sewage enter the sewage discharge section with the sewage. (3) The sewage entering the sewage discharge section begins to flow faster due to the change in the flow slope, which creates a certain scouring force on the conveyor belt, washing away the fine mud and other attachments adhering to the conveyor belt. The fine mud and other attachments are discharged with the sewage. (4) Since the direction of the conveyor belt is opposite to the direction of the sewage flow, the fine sand and stone powder that are settled at the bottom of the conveyor belt in the fine sand sedimentation and recovery section of the tailings sewage or sand washing sewage will slowly move towards the end of the fine sand control and dry discharge section under the drive of the conveyor belt, and gradually move out of the water surface. In the conveyor belt with a positive upward angle, the saturated water in the sedimentation layer is controlled out while moving, so that the sedimentation layer is gradually dehydrated and forms a fine sand sedimentation layer with a low water content. When the dehydrated fine sand sedimentation layer runs to the drive roller, it is unloaded from the drive roller along with the conveyor belt, thus completing the dehydration and dry discharge process of ultrafine sand.

Images