Electronic grade polysilicon screening device

Abstract

The present invention proposes an electronic-grade polysilicon screening device, comprising: a first conveying device, the first conveying device comprising a first screen plate, the first screen plate being provided with first screen holes; a second conveying device, the second conveying device being arranged at one end of the movement direction of the first screen plate, the second conveying device comprising a second screen plate, the second screen plate being provided with second screen holes penetrating the second screen plate along the second direction, the diameter of the first screen hole being smaller than the diameter of the second screen hole; thereby, the electronic-grade polysilicon screening device can avoid generating a large amount of debris and powder in the process of screening electronic-grade polysilicon, thereby ensuring clean production, preventing electronic-grade polysilicon from being contaminated, and improving production efficiency.

Description

Technical Field

[0001] The present application relates to the semiconductor field, and in particular, to an electronic-grade polysilicon screening device. Background Art

[0002] The modified Siemens method is the mainstream process for the production of electronic-grade polysilicon. Electronic-grade polysilicon rods produced by chemical vapor deposition need to be processed into blocks when they are handed over to downstream for use. At present, the crushing process cannot completely control the size of the silicon material after crushing, so the silicon material needs to be screened by size. The related technology uses a crawler-type mobile screening machine. Although it has a simple structure and occupies a small area, the screening effect is not ideal and it is easy to contaminate polysilicon. There is also a silicon block vibration screening device. Although it increases the screening speed, a large amount of powder will be generated during the vibration process. The present application aims to propose an electronic-grade polysilicon screening device to solve the above problems. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] In one aspect of the present invention, an electronic-grade polysilicon screening device is proposed, comprising: a first conveying device, the first conveying device comprising a first screen plate, the first screen plate can selectively reciprocate between the two ends of the first conveying device along a first direction, the first screen plate is provided with a first screen hole penetrating the first screen plate along a second direction; a first material receiving bin, the first material receiving bin is provided at one side of the first conveying device along the second direction and directly opposite to the first conveying device, a first accommodating cavity suitable for accommodating the electronic-grade polysilicon is formed in the first material receiving bin; a second conveying device, the second conveying device is provided at one end of the first screen plate in the direction of movement, the second conveying device The device comprises a second screen plate, the second screen plate can selectively reciprocate between the two ends of the second conveying device along the first direction, the second screen plate is provided with a second screen hole penetrating the second screen plate along the second direction, the diameter of the first screen hole is smaller than the diameter of the second screen hole; a second material receiving bin, the second material receiving bin is provided on one side of the second conveying device along the second direction and directly opposite to the second conveying device, and a second accommodating cavity suitable for accommodating the electronic-grade polysilicon is formed in the second material receiving bin; wherein the first direction is the extension direction of the first screen plate and the second screen plate, and the second direction is the thickness direction of the first screen plate and the second screen plate. Thus, the electronic-grade polysilicon screening device can avoid the generation of a large amount of debris and micropowder in the process of screening electronic-grade polysilicon, ensure clean production, prevent electronic-grade polysilicon from being contaminated, and improve production efficiency.

[0005] According to some embodiments of the present invention, the electronic-grade polysilicon screening device also includes: a first dust suction pipe, one end of which is connected to the first material receiving bin, and the other end of which is connected to the dust suction device; a first pipe, a circulation channel suitable for dust circulation is formed inside the first pipe, one end of which is connected to the first material receiving bin, and the other end of which is connected to the second material receiving bin.

[0006] According to some embodiments of the present invention, the diameter of the first sieve hole is 45 mm to 55 mm; and / or the diameter of the second sieve hole is 90 mm to 110 mm.

[0007] According to some embodiments of the present invention, the electronic-grade polysilicon screening device also includes: a feeding device, wherein a feed port is formed at one end of the feeding device away from the first conveying device, and an outlet is formed at one end of the feeding device toward the first conveying device, and a diameter of the feed port is larger than a diameter of the outlet.

[0008] According to some embodiments of the present invention, the electronic-grade polysilicon screening device further includes: a second dust suction pipe, one end of the second dust suction pipe is connected to the feeding device, and the other end of the second dust suction pipe is connected to the first dust suction pipe.

[0009] According to some embodiments of the present invention, the distance between the discharge port and the first sieve plate is 20 cm to 30 cm.

[0010] According to some embodiments of the present invention, at least a portion of an inner circumferential wall of the feeding device is coated with polyurethane.

[0011] According to some embodiments of the present invention, the electronic-grade polysilicon screening device further includes: a third material receiving bin, which is arranged at one end of the movement direction of the second screening plate, and a third accommodating cavity suitable for accommodating the electronic-grade polysilicon is formed in the third material receiving bin.

[0012] According to some embodiments of the present invention, the electronic-grade polysilicon screening device also includes: a first material receiving box, the first material receiving box is arranged in the first material receiving bin, and a fourth accommodating chamber suitable for accommodating the electronic-grade polysilicon is formed in the first material receiving box; and / or a second material receiving box, the second material receiving box is arranged in the second material receiving bin, and a fifth accommodating chamber suitable for accommodating the electronic-grade polysilicon is formed in the second material receiving box; and / or a third material receiving box, the third material receiving box is arranged in the third material receiving bin, and a sixth accommodating chamber suitable for accommodating the electronic-grade polysilicon is formed in the third material receiving box.

[0013] According to some embodiments of the present invention, at least part of the surface of the first screen plate and / or at least part of the surface of the second screen plate is coated with polyurethane; at least part of the inner wall of the first material receiving box and / or at least part of the inner wall of the second material receiving box and / or at least part of the inner wall of the third material receiving box is coated with polyurethane. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0015] Figure 1 A schematic structural diagram of an electronic-grade polysilicon screening device according to an embodiment of the present invention is shown.

[0016] Reference numerals:

[0017] 1000: electronic-grade polysilicon screening device; 1100: first conveying device; 1110: first screening plate; 1111: first sub-screening plate; 1112: second sub-screening plate; 1120: driving device; 1200: first material receiving bin; 1300: second conveying device; 1310: second screening plate; 1311: third sub-screening plate; 1312: fourth sub-screening plate; 1400: second material receiving bin; 100: first dust suction duct; 1500: feeding device; 1510: feeding port; 1520: discharging port; 200: second dust suction duct; 1600: third material receiving bin; 1210: first material receiving box; 1410: second material receiving box; 1610: third material receiving box. DETAILED DESCRIPTION

[0018] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0019] In one aspect of the present invention, an electronic grade polysilicon screening device 1000 is provided, referring to Figure 1 The electronic-grade polysilicon screening device 1000 includes a first conveying device 1100 , a first material receiving bin 1200 , a second conveying device 1300 and a second material receiving bin 1400 .

[0020] The first conveying device 1100 includes a first screen plate 1110, the first screen plate 1110 can selectively reciprocate between the two ends of the first conveying device 1100 along the first direction, and the first screen plate 1110 is provided with a first screen hole (not shown in the figure) penetrating the first screen plate 1110 along the second direction. Specifically, the first conveying device 1100 may include a first screen plate 1110 and a driving device 1120, the first screen plate 1110 includes a first sub-screen plate 1111 and a second sub-screen plate 1112, the first sub-screen plate 1111 and the second sub-screen plate 1112 are arranged along the second direction, one end of the first sub-screen plate 1111 along the first direction is connected to one end of the second sub-screen plate 1112 along the first direction, the other end of the first sub-screen plate 1111 along the first direction is connected to the other end of the second sub-screen plate 1112 along the first direction, and the driving device 1120 is arranged between the first sub-screen plate 1111 and the second sub-screen plate 1112. When the first sub-screen plate 1111 moves from one end toward the other end of the first conveying device 1100, the second sub-screen plate 1112 moves from the other end of the first conveying device 1100 toward one end of the first conveying device 1100, and both the first sub-screen plate 1111 and the second sub-screen plate 1112 are formed with a bearing surface for bearing electronic-grade polysilicon.

[0021] The first material receiving bin 1200 is arranged on one side of the first conveying device 1100 along the second direction and directly opposite to the first conveying device 1100, and a first accommodating cavity suitable for accommodating electronic-grade polysilicon is formed in the first material receiving bin 1200. Specifically, a first opening is provided at one end of the first material receiving bin 1200 facing the first conveying device 1100, and the electronic-grade polysilicon falling through the first sieve hole falls into the first accommodating cavity from the first opening to collect the electronic-grade polysilicon. It should be noted that the term "directly opposite" here refers to the overlap of at least a portion of the area of ​​the first sieve plate 1110 with the first opening. Preferably, the first material receiving bin 1200 is located directly below the first sieve plate 1110, and the size of the first sieve plate 1110 is the same as the size of the first opening, thereby allowing all the electronic-grade polysilicon to fall into the first material receiving bin 1200.

[0022] The second conveying device 1300 is arranged at one end of the moving direction of the first screen plate 1110. For example, when the first screen plate 1110 moves from one end of the first conveying device 1100 toward the other end of the first conveying device 1100, the second conveying device 1300 is arranged at the other end of the first conveying device 1100. The second conveying device 1300 includes a second screen plate 1310. The second screen plate 1310 can selectively move back and forth between the two ends of the second conveying device 1300 along the first direction. The second screen plate 1310 is provided with a second screen hole (not shown in the figure) penetrating the second screen plate 1310 along the second direction. The diameter of the first screen hole is smaller than the diameter of the second screen hole. Specifically, the second conveying device 1300 may include a second screen plate 1310 and a driving device 1120, the second screen plate 1310 includes a third sub-screen plate 1311 and a fourth sub-screen plate 1312, the third sub-screen plate 1311 and the fourth sub-screen plate 1312 are arranged along the second direction, one end of the third sub-screen plate 1311 along the first direction is connected to one end of the fourth sub-screen plate 1312 along the first direction, the other end of the third sub-screen plate 1311 along the first direction is connected to the other end of the fourth sub-screen plate 1312 along the first direction, and the driving device 1120 is disposed between the third sub-screen plate 1311 and the fourth sub-screen plate 1312. When the third sub-screen plate 1311 moves from one end to the other end of the second conveyor 1300, the fourth sub-screen plate 1312 moves from the other end of the second conveyor 1300 to one end of the second conveyor 1300, and the third sub-screen plate 1311 and the fourth sub-screen plate 1312 are both formed with a bearing surface for bearing electronic-grade polysilicon. Thus, small-sized electronic-grade polysilicon is collected in the first receiving bin 1200, and large-sized electronic-grade polysilicon falls onto the second screen plate 1310 for further screening.

[0023] The second material receiving bin 1400 is arranged on one side of the second conveying device 1300 along the second direction and directly opposite to the second conveying device 1300. A second accommodating cavity suitable for accommodating electronic-grade polysilicon is formed in the second material receiving bin 1400, wherein the first direction is the extension direction of the first screen plate 1110 and the second screen plate 1310, and the second direction is the thickness direction of the first screen plate 1110 and the second screen plate 1310. Specifically, a second opening is provided at one end of the second material receiving bin 1400 facing the second conveying device 1300, and the electronic-grade polysilicon falling through the second sieve hole falls into the second accommodating cavity from the second opening to collect the electronic-grade polysilicon. It should be noted that the directly opposite referred to here means that at least part of the area of ​​the second screen plate 1310 overlaps with the second opening. Preferably, the second material receiving bin 1400 is located directly below the second screening plate 1310, and the size of the second screening plate 1310 is the same as the size of the second opening, so that all the electronic-grade polysilicon can fall into the second material receiving bin 1400. Thus, large-sized electronic-grade polysilicon is collected in the second material receiving bin 1400, and the screening of small-sized and large-sized electronic-grade polysilicon can be completed.

[0024] The electronic-grade polysilicon screening device 1000 involved in the present invention screens by transmission. Since the screening plate is a rotating structure, silicon materials that do not pass through the screening holes will not accumulate on the screening plate, and will not cause subsequent silicon materials to be unable to pass through the screening holes. The silicon materials can move with the movement of the screening plate. The screening holes on the screening plate screen electronic-grade polysilicon of different sizes. The diameter of the first screening hole is smaller than the diameter of the second screening hole. Small-sized electronic-grade polysilicon first falls into the first material receiving bin 1200, and large-sized electronic-grade polysilicon falls into the second material receiving bin 1400. Unlike vibration screening, transmission screening can reduce the generation of dust, reduce the friction of silicon materials on the screening plate, prevent electronic-grade polysilicon from being contaminated, and improve screening efficiency.

[0025] According to some embodiments of the present invention, the shapes of the first sub-screening plate 1111, the second sub-screening plate 1112, the third sub-screening plate 1311 and the fourth sub-screening plate 1312 are not particularly limited. Specifically, in the present application, the length of the first sub-screening plate 1111, the second sub-screening plate 1112, the third sub-screening plate 1311 and the fourth sub-screening plate 1312 can be 1.5 meters and the width can be 80 cm. The distance between the first sub-screening plate 1111 and the second sub-screening plate 1112 can be 20 cm, and the distance between the third sub-screening plate 1311 and the fourth sub-screening plate 1312 can also be 20 cm.

[0026] According to some embodiments of the present invention, reference Figure 1The electronic-grade polysilicon screening device 1000 may further include a first dust suction pipe 100 and a first pipe (not shown in the figure), one end of the first dust suction pipe 100 is connected to the first material receiving bin 1200, the other end of the first dust suction pipe 100 is connected to the dust suction device, a circulation channel suitable for dust circulation is formed inside the first pipe, one end of the first pipe is connected to the first material receiving bin 1200, and the other end of the first pipe is connected to the second material receiving bin 1400. Thus, even if a small amount of fine powder is generated during the screening process, it can be sucked away by the dust suction device, further avoiding the generation of a large amount of fine powder, so that the screening process is carried out in a dust-free environment.

[0027] According to some embodiments of the present invention, the shapes of the first sieve hole and the second sieve hole are not particularly limited, and can be designed according to the morphology of electronic-grade polysilicon. The first sieve plate 1110 can be provided with first sieve holes of the same shape, or it can be designed as a combination of first sieve holes of different shapes. The design of the second sieve hole refers to the first sieve hole, which will not be repeated here. According to other specific embodiments of the present invention, the diameter of the second sieve hole of the first sieve hole is also not particularly limited. For example, the diameter of the first sieve hole can be 45mm to 55mm; and / or the diameter of the second sieve hole can be 90mm to 110mm. Thus, electronic-grade polysilicon of different sizes is screened.

[0028] According to some embodiments of the present invention, reference Figure 1 The electronic-grade polysilicon screening device 1000 further includes: a feeding device 1500, wherein a feeding port 1510 is formed at one end of the feeding device 1500 away from the first conveying device 1100, and a discharging port 1520 is formed at one end of the feeding device 1500 facing the first conveying device 1100, wherein the diameter of the feeding port 1510 is greater than the diameter of the discharging port 1520. Specifically, the feeding device 1500 can be constructed as a funnel, and the electronic-grade polysilicon is discharged onto the first screening plate 1110 through the funnel. By adjusting the size of the discharging port 1520, the electronic-grade polysilicon can be controlled to fall onto the first screening plate 1110 in small quantities and multiple times, further avoiding the generation of a large amount of debris and micro powder. Furthermore, the feeding device 1500 can hold 30 kg of silicon material per batch, and the size of the silicon material can be controlled to be between 10 mm and 100 mm.

[0029] According to some embodiments of the present invention, reference Figure 1 The electronic-grade polysilicon screening device 1000 further includes: a second dust suction pipe 200, one end of which is connected to the feeding device 1500, and the other end of which is connected to the first dust suction pipe 100. Thus, the dust suction device can simultaneously remove dust from the feeding device 1500 and the receiving bin, further avoiding the generation of a large amount of fine powder, so that the screening process can be carried out in a dust-free environment.

[0030] According to some embodiments of the present invention, the distance between the discharge port 1520 and the first sieve plate 1110 may be 20 cm to 30 cm.

[0031] According to some embodiments of the present invention, in order to prevent electronic-grade polysilicon from being contaminated, at least part of the inner circumference of the feeding device 1500 is coated with polyurethane. Preferably, the entire inner circumference of the feeding device 1500 is coated with polyurethane to further improve the purity of the electronic-grade polysilicon.

[0032] According to some embodiments of the present invention, reference Figure 1 The electronic-grade polysilicon screening device 1000 further includes: a third material receiving bin, the third material receiving bin 1600 is arranged at one end of the movement direction of the second screen plate 1310, and a third accommodating cavity suitable for accommodating electronic-grade polysilicon is formed in the third material receiving bin 1600. Specifically, when the second screen plate 1310 moves from one end of the second conveying device 1300 toward the other end of the second conveying device 1300, the third material receiving bin 1600 is arranged at the other end of the first conveying device 1100. The electronic-grade polysilicon that falls on the second screen plate 1310 without passing through the second screening hole falls into the third material receiving bin 1600.

[0033] According to some embodiments of the present invention, reference Figure 1 , the electronic-grade polysilicon screening device 1000 may further include: a first material receiving box 1210, the first material receiving box 1210 is arranged in the first material receiving bin 1200, and a fourth accommodating chamber suitable for accommodating electronic-grade polysilicon is formed in the first material receiving box 1210; and / or a second material receiving box 1410, the second material receiving box 1410 is arranged in the second material receiving bin 1400, and a fifth accommodating chamber suitable for accommodating electronic-grade polysilicon is formed in the second material receiving box 1410; and / or a third material receiving box 1610, the third material receiving box 1610 is arranged in the third material receiving bin 1600, and a sixth accommodating chamber suitable for accommodating electronic-grade polysilicon is formed in the third material receiving box 1610. Thus, when the first material receiving bin 1200, the second material receiving bin 1400 and the third material receiving bin 1600 are all provided with material receiving boxes, the classified electronic-grade polysilicon can be collected more conveniently.

[0034] According to some embodiments of the present invention, at least part of the surface of the first sieve plate 1110 and / or at least part of the surface of the second sieve plate 1310 is coated with polyurethane; at least part of the inner wall of the first material receiving box 1210 and / or at least part of the inner wall of the second material receiving box 1410 and / or at least part of the inner wall of the third material receiving box 1610 is coated with polyurethane. Preferably, the entire material of the first sieve plate 1110 and the second sieve plate 1310 are both polyurethane, further preventing contamination of electronic-grade polysilicon. The first material receiving box 1210, the second material receiving box 1410 and the third material receiving box 1610 are made of stainless steel, and the inner walls of the material receiving boxes are coated with polyurethane. As a result, the entire screening process of electronic-grade polysilicon is in direct contact with polyurethane, further preventing contamination of electronic-grade polysilicon.

[0035] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0039] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0040] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An electronic grade polysilicon screening device, characterized in that: include: a first conveying device, the first conveying device comprising a first screen plate and a driving device, the first screen plate can selectively reciprocate between two ends of the first conveying device along a first direction, the first screen plate is provided with a first screen hole penetrating the first screen plate along a second direction, the first screen plate comprises a first sub-screen plate and a second sub-screen plate, the first sub-screen plate and the second sub-screen plate are arranged along the second direction, one end of the first sub-screen plate along the first direction is connected to one end of the second sub-screen plate along the first direction, the other end of the first sub-screen plate along the first direction is connected to the other end of the second sub-screen plate along the first direction, the driving device is arranged between the first sub-screen plate and the second sub-screen plate, when the first sub-screen plate moves from one end toward the other end of the first conveying device, the second sub-screen plate moves from the other end of the first conveying device toward one end of the first conveying device, and both the first sub-screen plate and the second sub-screen plate are formed with a bearing surface for bearing electronic-grade polysilicon; a first material receiving bin, which is disposed on one side of the first conveying device along the second direction and directly faces the first conveying device, and has a first accommodating cavity suitable for accommodating the electronic-grade polysilicon formed therein; a second conveying device, the second conveying device is arranged at one end of the moving direction of the first screen plate, the second conveying device comprises a second screen plate and a driving device, the second screen plate can selectively reciprocate between the two ends of the second conveying device along the first direction, the second screen plate is provided with a second screen hole penetrating the second screen plate along the second direction, the diameter of the first screen hole is smaller than the diameter of the second screen hole, the second screen plate comprises a third sub-screen plate and a fourth sub-screen plate, the third sub-screen plate and the fourth sub-screen plate are arranged along the second direction, one end of the third sub-screen plate along the first direction is connected to one end of the fourth sub-screen plate along the first direction, the other end of the third sub-screen plate along the first direction is connected to the other end of the fourth sub-screen plate along the first direction, the driving device is arranged between the third sub-screen plate and the fourth sub-screen plate, when the third sub-screen plate moves from one end toward the other end of the second conveying device, the fourth sub-screen plate moves from the other end of the second conveying device toward one end of the second conveying device, and the third sub-screen plate and the fourth sub-screen plate are both formed with a bearing surface for bearing electronic grade polysilicon; a second material receiving bin, the second material receiving bin being arranged on one side of the second conveying device along the second direction and facing the second conveying device, and a second accommodating cavity suitable for accommodating the electronic-grade polysilicon being formed in the second material receiving bin; The first direction is an extension direction of the first screen plate and the second screen plate, and the second direction is a thickness direction of the first screen plate and the second screen plate.

2. The electronic grade polysilicon screening device according to claim 1, characterized in that: Also includes: a first dust collection pipe, one end of which is in communication with the first material receiving bin, and the other end of which is connected to a dust collection device; A first pipe, wherein a circulation channel suitable for dust circulation is formed inside the first pipe, one end of the first pipe is connected to the first material receiving bin, and the other end of the first pipe is connected to the second material receiving bin.

3. The electronic grade polysilicon screening device according to claim 2, characterized in that: The diameter of the first sieve hole is 45 mm to 55 mm; and / or the diameter of the second sieve hole is 90 mm to 110 mm.

4. The electronic grade polysilicon screening device according to claim 3, characterized in that: Also includes: A feeding device, wherein a feeding port is formed at one end of the feeding device away from the first conveying device, and a discharging port is formed at one end of the feeding device facing the first conveying device, and a diameter of the feeding port is greater than a diameter of the discharging port.

5. The electronic grade polysilicon screening device according to claim 4, characterized in that: Also includes: A second dust suction pipe, one end of which is connected to the feeding device, and the other end of which is connected to the first dust suction pipe.

6. The electronic grade polysilicon screening device according to claim 4, characterized in that: The distance between the discharge port and the first screening plate is 20 cm to 30 cm.

7. The electronic grade polysilicon screening device according to claim 6, characterized in that: At least a portion of the inner peripheral wall of the feeding device is coated with polyurethane.

8. The electronic grade polysilicon screening device according to claim 1, characterized in that: Also includes: A third material receiving bin is provided at one end of the moving direction of the second screening plate, and a third accommodating cavity suitable for accommodating the electronic-grade polysilicon is formed in the third material receiving bin.

9. The electronic grade polysilicon screening device according to claim 8, characterized in that: Also includes: A first material receiving box, wherein the first material receiving box is disposed in the first material receiving bin, and a fourth accommodating cavity suitable for accommodating the electronic-grade polysilicon is formed in the first material receiving box; and / or a second material receiving box, wherein the second material receiving box is disposed in the second material receiving bin, and a fifth accommodating cavity suitable for accommodating the electronic-grade polysilicon is formed in the second material receiving box; and / or A third material receiving box is arranged in the third material receiving bin, and a sixth accommodating cavity suitable for accommodating the electronic-grade polysilicon is formed in the third material receiving box.

10. The electronic grade polysilicon screening device according to claim 9, characterized in that: At least a portion of the surface of the first sieve plate and / or at least a portion of the surface of the second sieve plate is coated with polyurethane; At least part of the inner wall of the first material receiving box and / or at least part of the inner wall of the second material receiving box and / or at least part of the inner wall of the third material receiving box is coated with polyurethane.

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