Multi-stage screening equipment and method for silica sand processing

Abstract

The present invention discloses a multi-stage screening device and method for silica sand processing, which relates to the field of silica sand screening technology, and comprises a horizontally arranged shell, wherein a rotatable outer screen drum is provided in the shell, wherein a rotatable inner screen drum is provided in the outer screen drum, wherein the mesh size of the inner screen drum is larger than that of the outer screen drum, and a large-particle discharge channel is provided between the outer screen drum and the shell, wherein the inner screen drum, the outer screen drum and the shell are all truncated cone-shaped. The present invention adopts an outer screen drum for feeding, and the screening area of ​​the outer screen drum is much larger than that of the inner screen drum. When processing the same amount of silica sand, the unit load of the outer screen drum is much smaller than that of the inner screen drum, thereby overcoming the defects of the traditional silica sand screening process in which the unit load of the inner screen drum is significantly exceeded during feeding and screening, and the defects in that the screen impedance is multiplied and the probability of screen hole clogging is increased due to the excessive thickness of the inner screen drum material layer.

Description

Technical Field

[0001] The present invention relates to the technical field of silica sand screening, in particular to a multi-stage screening device and method for silica sand processing. Background Art

[0002] Multi-stage screening is the core process link for achieving particle size gradient grading of silica sand. Through precise grading of silica sand particle size, the coordinated optimization of silica sand materials in terms of physical and chemical performance improvement, intensive resource utilization and matching degree with downstream application scenarios is guaranteed.

[0003] When traditional sand is graded by particle size gradient, the screening equipment uses a multi-layer screen drum nested structure to perform multi-stage screening, such as Figure 1 The three-stage screening equipment shown is composed of an outer sieve with a larger mesh size and an inner sieve with a smaller mesh size. During operation, the silica sand placed on the inner sieve is graded by rotation. Based on the particle size differences of the silica sand (A>B>C), three levels of products are formed after screening: the largest particle size A particles are retained in the inner sieve and collected separately; the medium-sized particle B particles are retained in the outer sieve for dedicated line recovery; the smallest particle C particles are discharged through the sieve holes of the outer sieve and are independently captured. The grading device achieves three-level precise separation of silica sand materials through a multi-layer sleeve-type structural design.

[0004] However, in the above-mentioned silica sand screening process, due to the structural constraints of the inner screen drum (small diameter and low bearing strength), there are two types of core process defects when the processed silica sand falls directly into the inner screen drum: first, due to the difference in drum area, the unit load of the inner screen drum is significantly exceeded, aggravating the structural fatigue of the screen body and the degradation of service life; second, due to the low diameter ratio characteristics and mechanical strength limitations, the thickness of the material layer in the inner screen drum increases sharply, causing the dynamic screening efficiency to deteriorate, which is specifically manifested in the coupling failure phenomenon of the doubling of the screen penetration impedance and the gradient increase of the probability of screen hole clogging. Summary of the Invention

[0005] The object of the present invention is to provide a multi-stage screening device and method for silica sand processing to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a multi-stage screening device for silica sand processing, comprising a horizontally arranged housing, a rotatable outer sieve drum being sheathed within the housing, a rotatable inner sieve drum being sheathed within the outer sieve drum, the inner sieve drum having a larger mesh size than the outer sieve drum, a large particle discharge channel being provided between the outer sieve drum and the housing, the inner sieve drum, the outer sieve drum, and the housing all being truncated cone-shaped; and further comprising:

[0007] A receiving plate is installed between the inner sieve drum and the outer sieve drum to prevent the silica sand sieved by the outer sieve drum from falling into the inner cavity of the outer sieve drum and to receive and discharge the silica sand sieved by the inner sieve drum; a fine particle discharge channel and a medium particle discharge channel are respectively provided between the receiving plate and the inner sieve drum and the outer sieve drum;

[0008] A plurality of baffles are equidistantly distributed along the circumference of the outer sieve drum and each baffle extends radially to intersect with the axis of the outer sieve drum; a cavity is formed between two adjacent baffles, the outer sieve drum and the shell;

[0009] The feeding port is used to fill the chamber with silica sand;

[0010] The pusher assembly is installed on the outer screen drum and is used to push the accumulated silica sand away from the baffle.

[0011] As a further technical solution of the present invention: the baffle is a V-shaped plate with an obtuse angle, and the opening of the bent portion faces away from the rotation direction of the outer screen drum.

[0012] As a further technical solution of the present invention: the pushing assembly includes a pushing plate, which is sealed and embedded in the baffle. A power assembly is provided on the large diameter end of the outer screen drum, and the power assembly is used to separate the pushing plate from the baffle.

[0013] As a further technical solution of the present invention: the power assembly includes a telescopic part, which is located at the large diameter end of the outer screen drum and rotates synchronously with the outer screen drum. One end of the telescopic part is hinged with a guide plate, and the guide plate is connected to the screen surface of the outer screen drum along the circumference of the outer screen drum. The guide plate and the push plate are assembled to form a hopper.

[0014] As a further technical solution of the present invention: it also includes an auxiliary pushing assembly, which includes a connecting plate, one end of the connecting plate is rotatably connected to a connecting piece, the other end of the connecting plate is inserted into the push plate, the end of the push plate away from the connecting plate is rotatably connected to the guide plate, the connecting piece is slidably connected to a movable piece fixedly connected to the guide plate, a telescopic piece 2 is fixedly installed on the movable piece, and the movable end of the telescopic piece 2 is fixedly connected to the connecting piece.

[0015] As a further technical solution of the present invention: it also includes a support assembly, which includes a ring body, a base frame and a bracket fixedly connected to the outer screen drum, the ring body is rotatably connected to the large diameter end of the shell, and the other end of the telescopic member is hinged to the ring body; the base frame is located below the shell, and the bracket is arranged on one side of the base frame and fixedly connected to the material receiving plate.

[0016] As a further technical solution of the present invention: the bracket is slidably connected to the base frame.

[0017] As a further technical solution of the present invention: a blanking assembly is provided on the base frame, and the blanking assembly includes a first blanking ring fixedly connected to the base frame, a first blanking channel is provided on the first blanking ring, a second blanking ring is fixedly connected to the outside of the first blanking ring, and a second blanking channel is provided on the second blanking ring.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention adopts an outer screen drum for feeding, and the screening area of ​​the outer screen drum is much larger than that of the inner screen drum. When processing the same silica sand, the unit load of the outer screen drum is much smaller than that of the inner screen drum, which overcomes the defects of the traditional silica sand screening process in which the unit load of the inner screen drum is significantly exceeded during feeding and screening, and the defects in the doubling of the screening impedance and the gradient increase of the probability of clogging of the screen holes caused by the excessive thickness of the material layer of the inner screen drum. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the inner and outer sieve drums of the three-stage screening equipment, where small figure (a) is a schematic diagram of the state when feeding to the inner sieve drum, and small figure (b) is a schematic diagram of the state after screening is completed;

[0021] Figure 2 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0023] Figure 4 Schematic diagram of the connection structure between the inner sieve drum, the outer sieve drum and the housing of the present invention;

[0024] Figure 5 Schematic diagram of the positional relationship between the chamber, the shell and the outer sieve drum of the present invention;

[0025] Figure 6 Schematic diagram of the positional relationship between the receiving plate, the outer screen drum and the ring body of the present invention;

[0026] Figure 7 Schematic diagram of the inner sieve drum, outer sieve drum, housing, large particle discharge channel, medium particle discharge channel, and fine particle discharge channel of the present invention;

[0027] Figure 8 It is a side view of the large particle discharging channel, the medium particle discharging channel, the fine particle discharging channel and the return material area of ​​the present invention;

[0028] Figure 9 Schematic diagram of the positional relationship between the baffle, the accommodating groove and the telescopic member 1 of the present invention;

[0029] Figure 10 Schematic diagram of the positional relationship between the push plate, telescopic member 1, telescopic member 2 and baffle of the present invention;

[0030] Figure 11 Schematic diagram of the positional relationship between the guide plate and the push plate, and between the push plate, the connecting plate and the connecting member of the present invention;

[0031] Figure 12 This is a schematic diagram of the present invention after the movable piece and the second telescopic member, as well as the baffle and the push plate are separated;

[0032] Figure 13 Schematic diagram of the connection between the telescopic member 2 and the movable piece of the present invention;

[0033] Figure 14 is a schematic diagram of a guide plate of the present invention;

[0034] Figure 15 Schematic diagram of the initial accumulation layer and the long accumulation layer of the material of the present invention;

[0035] Figure 16 This is a schematic diagram of the telescopic member of the present invention pushing the guide plate to move;

[0036] Figure 17 Schematic diagram of the push plate and the guide plate moving relative to the baffle when pushing materials according to the present invention;

[0037] Figure 18 Schematic diagram of the positional relationship between the housing, the first blanking ring, and the first blanking channel of the present invention;

[0038] Figure 19 Schematic diagram of the positional relationship between the housing, the second blanking ring, and the second blanking channel of the present invention;

[0039] Figure 20 Schematic diagram of the first blanking ring and the second blanking ring in cross section according to the present invention;

[0040] Figure 21 This is a schematic diagram of the connection relationship between the material receiving plate, the inner screen drum and the bracket of the present invention;

[0041] Figure 22 Schematic diagram of the positional relationship between the ring body and the outer screen drum, and between the guide plate and the telescopic member 1 of the present invention.

[0042] In the accompanying drawings: 1. Inner screen drum; 2. Outer screen drum; 3. Shell; 4. Receiving plate; 5. Baffle; 6. Chamber; 7. Loading port; 8. Displacement sensor; 9. Push plate; 10. Telescopic part 1; 11. Guide plate; 12. Connecting plate; 13. Connecting part; 14. Telescopic part 2; 15. Movable sheet; 16. Ring body; 17. Base frame; 18. Bracket; 19. First unloading ring; 20. First unloading channel; 21. Second unloading ring; 22. Second unloading channel; 23. Return material area; 24. Large particle discharging channel; 25. Medium particle discharging channel; 26. Fine particle discharging channel; 27. Annular groove; 28. Motor; 29. ​​Roller; A1. Initial accumulation layer of silica sand; A2. Long accumulation layer. DETAILED DESCRIPTION

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.

[0044] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0045] See also Figure 1-Figure 22 The present invention provides a technical solution: a multi-stage screening device for silica sand processing, used for screening silica sand of different particle sizes, comprising a horizontally arranged shell 3, a rotatable outer sieve drum 2 is provided in the shell 3, a rotatable inner sieve drum 1 is provided in the outer sieve drum 2, the inner sieve drum 1, the outer sieve drum 2 and the shell 3 are all frustum-shaped and coaxially installed, the mesh number of the inner sieve drum 1 is larger than that of the outer sieve drum 2, and a large-particle discharge channel 24 is provided between the outer sieve drum 2 and the shell 3; it also includes a receiving plate 4, a plurality of baffles 5, a feeding port 7 for filling silica sand in the chamber 6, and a pushing assembly; wherein the number of baffles 5 can be determined according to actual screening requirements, and the baffle 5 is designed as a V-shaped plate with an obtuse angle and the opening of the bent portion faces away from the rotation direction of the outer sieve drum 2.

[0046] The receiving plate 4 is installed between the inner sieve drum 1 and the outer sieve drum 2, and is used to prevent the silica sand screened by the outer sieve drum 2 from falling into the inner cavity of the outer sieve drum 2 and to receive and discharge the silica sand screened by the inner sieve drum 1. A fine particle discharge channel 26 and a medium particle discharge channel 25 are respectively provided between the receiving plate 4 and the inner sieve drum 1 and the outer sieve drum 2.

[0047] The plurality of baffles 5 are equidistantly distributed along the circumference of the outer sieve drum 2 and each baffle 5 extends radially to intersect with the axis of the outer sieve drum 2 ; a chamber 6 is formed between two adjacent baffles 5 , the outer sieve drum 2 and the shell 3 .

[0048] The pushing assembly is installed on the outer screen drum 2 and is used to push the accumulated silica sand away from the baffle 5.

[0049] like Figure 2、 Figure 4-Figure 9 As shown in the figure: during the process of the inner sieve drum 1 and the outer sieve drum 2 rotating and screening, silica sand is sequentially added into the interior of each chamber 6 through the feeding port 7; the silica sand screening process in each chamber 6 is the same, and one of the chambers 6 is selected as an example to describe the silica sand screening process of the chamber 6;

[0050] The feeding port 7 is opened at the large diameter end of the shell 3, and the position of the feeding port 7 is in the area between c and a1, wherein the feeding port 7 is best set at point a; during feeding, the silica sand is evenly transported to the interior of the chamber 6 through the feeding port 7 by the vibrating feeder. The vibrating feeder is not shown in the figure. Its use and installation are conventional settings and are not described in detail. At this time, the baffle 5 is in an inclined state (the height of the end of the baffle 5 close to the large diameter end of the shell 3 is lower than the other end), and the silica sand is accumulated on the side of the baffle 5 close to the large diameter end of the shell 3; after the feeding is completed, the chamber 6 and the outer screen drum 2 rotate clockwise around the axis of the outer screen drum 2 at the same time. When the chamber 6 rotates past point a, the pushing assembly starts to quickly push the accumulated silica sand away from the baffle 5 The silica sand pushed away from the baffle 5 makes a spiral progressive motion along the curved screen surface of the outer screen drum 2, so that the silica sand is in full contact with the screen surface of the outer screen drum 2. Under the combined action of the gravity component and the rotation of the screen body, the silica sand produces axial tumbling, realizing the first-stage screening of the particle size; the setting of the pushing assembly can prevent the silica sand on the baffle 5 from moving in the groove formed by the baffle 5 and the outer screen drum 2, ensuring the screening effect of the chamber 6 during the movement from point a to point a1; when the chamber 6 moves from point a1 to point a2 across point a1, the silica sand retained on the outer screen drum 2 makes a parabolic motion along the tangent direction of the screen surface under the vector superposition of the Coriolis acceleration and the gravity acceleration. The movement of the silica sand and the screen hole form dynamic screening, thus completing the first-stage screening process of the silica sand in a single chamber 6. It should be noted that the pushing assembly can be intelligently controlled and automatically reset before the chamber 6 rotates to the position of the feeding port 7 again;

[0051] The silica sand that does not pass through the sieve holes of the outer sieve drum 2 is discharged from the equipment through the large-particle discharge channel 24. The silica sand that passes through the sieve holes of the outer sieve drum 2 falls to the area from point a to point a2 of the inner sieve drum 1 under the guidance of the receiving plate 4 and completes the second-stage screening of the silica sand through the rotating inner sieve drum 1.

[0052] During the second stage screening process, the silica sand that does not pass through the sieve holes of the inner sieve drum 1 is discharged from the equipment through the medium-grained discharge channel 25, and the silica sand that passes through the sieve holes of the inner sieve drum 1 falls into the fine-grained discharge channel 26 and is discharged from the equipment through the fine-grained discharge channel 26.

[0053] After the first-stage screening and the second-stage screening, the silica sand can be screened in multiple stages. When processing the same amount of silica sand, this equipment abandons the traditional feeding method of the inner screen drum 1 and adopts the outer screen drum 2 for feeding. The screening area of ​​the outer screen drum 2 is much larger than the screening area of ​​the inner screen drum 1. When processing the same silica sand, the unit load of the outer screen drum 2 is much smaller than that of the inner screen drum 1, which overcomes the defects of the traditional silica sand screening process in which the unit load of the inner screen drum 1 is significantly exceeded during feeding and screening, and the defects of the doubling of the screening impedance and the gradient increase of the probability of clogging of the screen holes caused by the excessively thick material layer of the inner screen drum 1.

[0054] In addition, during the specific implementation, two circulating conveyors should be installed at appropriate positions. The circulating conveyor can be an LSY cement screw conveyor, but is not limited to the LSY cement screw conveyor. The specific structure of the circulating conveyor is the existing technology, and the installation of the circulating conveyor is the conventional technology in this field. Therefore, the structure and installation of the circulating conveyor are not described in detail and are not shown in the figure. One of the circulating conveyors is used to input the silica sand discharged from the large-particle discharge channel 24 into the large-particle discharge channel 24 from the highest point of the large-particle discharge channel 24; the other circulating conveyor is used to input the silica sand discharged from the medium-particle discharge channel 25 into the medium-particle discharge channel 25 from the highest point of the medium-particle discharge channel 25 (the highest positions of the large-particle discharge channel 24 and the medium-particle discharge channel 25 are Figure 8 The return material area 23 is shown in the schematic diagram), so that the silica sand can be screened multiple times, ensuring the screening effect of the silica sand.

[0055] See Figure 7 、 Figure 11 、 Figure 12 as well as Figure 15 The pushing assembly includes a pushing plate 9 and a power assembly. The pushing plate 9 is sealed and embedded in the baffle 5. The power assembly is arranged on the large diameter end of the outer screen drum 2. The power assembly pushes the pushing plate 9 away from the baffle 5.

[0056] After the silica sand to be screened enters the chamber 6, it is guided by the baffle 5 and flows and accumulates on the push plate 9. During the process of the outer screen drum 2 rotating from point a to point a1, the potential energy of the silica sand carried on the push plate 9 gradually increases, and the tendency of the silica sand to move from the large diameter end to the small diameter end of the outer screen drum 2 becomes stronger, resulting in the initial accumulation layer (A1) of the silica sand on the push plate 9 evolving into a long accumulation layer (A2) with increasing length but decreasing height. Part of the silica sand on the push plate 9 is discharged out of the equipment through the groove formed by the baffle 5 and the outer screen drum 2, affecting the screening effect. A pushing assembly is provided. In the initial stage of the rotation from point a to point a1, the silica sand accumulated on the push plate 9 is directly and quickly pushed to the high point position of the chamber 6. Guided by the push plate 9, the pushed out silica sand makes a spiral progressive motion along the arc-shaped screen surface of the outer screen drum 2. Under the combined action of the gravity component and the rotation of the screen body, the silica sand rolls axially and fully contacts the screen surface of the outer screen drum 2.

[0057] Among them, the power component includes a telescopic part 10, which is located at the large diameter end of the outer screen drum 2 and rotates synchronously with the outer screen drum 2. One end of the telescopic part 10 is hinged with a guide plate 11, and the guide plate 11 is connected to the screen surface of the outer screen drum 2 by sliding along the circumference of the outer screen drum 2. The guide plate 11 and the push plate 9 are assembled to form an integrated hopper, so that the push plate 9 and the telescopic part 10 indirectly form a hinged relationship. When the push plate 9 needs to be separated from the baffle 5, the telescopic part 10 extends, and the guide plate 11 slides on the screen surface of the outer screen drum 2 along the circumference of the outer screen drum 2, driving the push plate 9 to make the same movement and separate from the baffle 5.

[0058] Furthermore, an auxiliary pushing assembly is provided for pushing out the silica sand remaining in the hopper to prevent the silica sand from being retained in the hopper and unable to be screened. The auxiliary pushing assembly includes a connecting plate 12, one end of the connecting plate 12 is rotatably connected to a connecting piece 13, the other end of the connecting plate 12 is inserted into the pushing plate 9, and the end of the pushing plate 9 away from the connecting plate 12 is rotatably connected to the guide plate 11, the connecting piece 13 is slidably connected to a movable piece 15 fixedly connected to the guide plate 11, and a telescopic piece 2 14 is fixedly installed on the movable piece 15, and the movable end of the telescopic piece 2 14 is fixedly connected to the connecting piece 13.

[0059] See 10- Figure 17 When the power component performs the action, the auxiliary pushing component also moves. During the action, the telescopic part 2 14 shortens and drives the connecting part 13 to move. The movement of the connecting part 13 drives the connecting plate 12 to move synchronously. The connecting plate 12 rotates under the limiting action of the push plate 9. At the same time, the push plate 9 also rotates synchronously. Finally, the push plate 9, the connecting plate 12 and the guide plate 11 are in a coplanar state. The hopper formed by the assembly of the guide plate 11 and the push plate 9 disappears, which solves the problem of residual silica sand in the hopper, making the silica sand screening more thorough; the telescopic part 10 and the telescopic part 2 14 can adopt one of the cylinders, electric cylinders and electric telescopic rods that can be controlled by wireless signals in the existing technology. The specific structure is not repeated here. The telescopic part 10 and the telescopic part 2 14 can both be controlled by the displacement sensor 8 to realize the extension and shortening of the telescopic part 10 and the telescopic part 2 14. The position where the displacement sensor 8 sends a signal can be installed according to actual production needs. It is a conventional setting and will not be repeated here.

[0060] A support assembly is also provided, which includes a ring body 16, a base frame 17 and a bracket 18 fixedly connected to the outer screen drum 2. The ring body 16 is rotatably connected to the large-diameter end of the shell 3, and the other end of the telescopic member 10 is hinged to the ring body 16; the base frame 17 is located below the shell 3, and the bracket 18 is slidably connected to one side of the base frame 17 and fixedly connected to the receiving plate 4.

[0061] See Figure 2 、 Figure 3 as well as Figure 22The bracket 18 slides relative to the base frame 17, and the bracket 18 can be removed from the inside of the base frame 17 to facilitate maintenance and installation of the inner screen drum 1 and the receiving plate 4;

[0062] The ring body 16 can be driven by a drive assembly, which can be a combination of a ring gear and a motor 28. A ring gear is fixed to the outer ring of the ring body 16, and the ring gear is engaged with a gear fixedly connected to the output shaft of the motor 28. The motor 28 is fixedly connected to the housing 3. A roller 29 is rotatably provided on the housing 3, and an annular groove 27 matching the roller 29 is provided on the ring body 16. When the ring body 16 rotates, the roller 29 rolls along the annular groove 27 to prevent the outer sieve drum 2 from detaching; in specific implementation, the outer sieve drum 2 and the inner sieve drum 1 also need to be assembled with the above structure to prevent detachment.

[0063] A blanking assembly is provided on the base frame 17, which includes a first blanking ring 19 fixedly connected to the base frame 17, a first blanking channel 20 is provided on the first blanking ring 19, a second blanking ring 21 is fixedly connected to the outside of the first blanking ring 19, and a second blanking channel 22 is provided on the second blanking ring 21.

[0064] See Figures 18-21 The large particle discharge channel 24 is connected to the first discharge channel 20 of the first discharge ring 19, and the medium particle discharge channel 25 is connected to the second discharge channel 22 on the second discharge ring 21, thereby realizing the separate recovery of silica sand and the transfer during subsequent circulation screening.

Claims

1. A multi-stage screening device for silica sand processing, comprising a horizontally arranged housing, a rotatable outer screen cylinder being sheathed in the housing, and a rotatable inner screen cylinder being sheathed in the outer screen cylinder, characterized in that: The mesh number of the inner sieve drum is larger than that of the outer sieve drum, a large particle discharge channel is provided between the outer sieve drum and the shell, and the inner sieve drum, the outer sieve drum and the shell are all truncated cone-shaped; further comprising: A receiving plate is installed between the inner sieve drum and the outer sieve drum to prevent the silica sand sieved by the outer sieve drum from falling into the inner cavity of the outer sieve drum and to receive and discharge the silica sand sieved by the inner sieve drum; a fine particle discharge channel and a medium particle discharge channel are respectively provided between the receiving plate and the inner sieve drum and the outer sieve drum; A plurality of baffles are equidistantly distributed along the circumference of the outer sieve drum and each baffle extends radially to intersect with the axis of the outer sieve drum; a cavity is formed between two adjacent baffles, the outer sieve drum and the shell; The feeding port is used to fill the chamber with silica sand; The feeding port is opened at the large diameter end of the shell. Silica sand is transported into the interior of the chamber through the feeding port, making the silica sand contact with the screen surface of the outer sieve drum, completing the first stage of particle size screening. The silica sand that passes through the sieve holes of the outer sieve drum falls to the inner sieve drum under the guidance of the receiving plate, and the second stage of silica sand screening is completed by the rotating inner sieve drum. The pusher assembly is installed on the outer screen drum and is used to push the accumulated silica sand away from the baffle; The baffle is a V-shaped plate with an obtuse angle, and the opening of the bent portion faces away from the rotation direction of the outer screen drum; The pushing assembly includes a pushing plate, which is sealed and embedded in the baffle. A power assembly is provided on the large diameter end of the outer screen drum, and the power assembly is used to separate the pushing plate from the baffle. The power assembly includes a telescopic member 1, which is located at the large-diameter end of the outer screen drum and rotates synchronously with the outer screen drum. One end of the telescopic member 1 is hinged with a guide plate, which is slidably connected to the screen surface of the outer screen drum along the circumference of the outer screen drum. The guide plate and the push plate are assembled to form a hopper; It also includes an auxiliary pushing assembly, which includes a connecting plate, one end of the connecting plate is rotatably connected to a connecting piece, the other end of the connecting plate is inserted into the push plate, the end of the push plate away from the connecting plate is rotatably connected to the guide plate, the connecting piece is slidably connected to a movable piece fixedly connected to the guide plate, a telescopic piece 2 is fixedly installed on the movable piece, and the movable end of the telescopic piece 2 is fixedly connected to the connecting piece.

2. The multi-stage screening device for silica sand processing according to claim 1, characterized in that: It also includes a support assembly, which includes a ring body, a base frame and a bracket fixedly connected to the outer screen drum. The ring body is rotatably connected to the large-diameter end of the shell, and the other end of the telescopic member is hinged to the ring body; the base frame is located below the shell, and the bracket is arranged on one side of the base frame and fixedly connected to the material receiving plate.

3. The multi-stage screening device for silica sand processing according to claim 2, characterized in that: The bracket is slidably connected to the base frame.

4. The multi-stage screening device for silica sand processing according to claim 3, characterized in that: A blanking assembly is provided on the base frame, and the blanking assembly includes a first blanking ring fixedly connected to the base frame, a first blanking channel is provided on the first blanking ring, a second blanking ring is fixedly connected to the outside of the first blanking ring, and a second blanking channel is provided on the second blanking ring.

5. A screening method using a multi-stage screening device for silica sand processing according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: S1: Pre-crushing and impurity removal of silicon ore: The silicon ore is coarsely crushed by a jaw crusher, and then iron is removed by a metal detector. The coarsely crushed silicon ore after iron removal is sent to a cone crusher for secondary crushing to control the material particle size to below 10mm; S2: Multi-stage screening: The product obtained in S1 is fed into each chamber in equal amounts through the feeding port, and the three-stage screening of the product obtained in S1 is completed by rotating the inner and outer sieve drums; S3: Magnetic separation enhancement: The materials obtained from S2 are respectively passed through an oil-cooled vertical ring high gradient magnetic separator with a magnetic separation intensity of 15,000 Gauss for four to five times of iron removal, and the iron impurity content of the materials obtained from S2 can be reduced to below 20ppm.

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