Polycrystalline silicon crushing device and polycrystalline silicon crushing method

Abstract

The present invention improves the yield of polycrystalline silicon having a desired particle size and sufficiently reduces the generated amount of fine powder of the polycrystalline silicon. A crushing device (1) for polycrystalline silicon (S) comprises a driving part (30) that sandwiches the polycrystalline silicon (S) between a first member (10) and a second member (20) so as to crush the polycrystalline silicon (S). The driving part (30) drives at least one of the first member (10) and the second member (20) such that the shortest interval (D1) between the first member (10) and the second member (20) is 17-30 mm.

Description

Polycrystalline silicon crushing device and polycrystalline silicon crushing method

[0001] The present invention relates to a polycrystalline silicon crushing device and a polycrystalline silicon crushing method.

[0002] Patent Document 1 discloses a method for crushing polycrystalline silicon using a jaw crusher that has a fixed blade and a movable blade and is capable of adjusting the shortest gap between the fixed blade and the movable blade to 2 to 16 mm.

[0003] Japanese Patent Application Publication No. 2015-047594

[0004] The shortest gap between the fixed blade and the movable blade disclosed in Patent Document 1 generates a large amount of polycrystalline silicon fine powder, which causes a problem that the yield of polycrystalline silicon with the desired particle size cannot be sufficiently high.

[0005] An object of one aspect of the present invention is to improve the yield of polycrystalline silicon having a desired particle size and to sufficiently reduce the amount of fine powder of polycrystalline silicon generated.

[0006] In order to solve the above-mentioned problems, one aspect of the present invention provides a polycrystalline silicon crushing device comprising: a first member; a second member arranged to face the first member; and a drive unit that drives at least one of the first member and the second member to crush the polycrystalline silicon by sandwiching the polycrystalline silicon between the first member and the second member, wherein the drive unit drives at least one of the first member and the second member so that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less.

[0007] Furthermore, a method for crushing polycrystalline silicon according to one aspect of the present invention includes a feeding step of feeding polycrystalline silicon between a first member and a second member arranged opposite the first member, and a driving step of driving at least one of the first member and the second member to crush the polycrystalline silicon by sandwiching the polycrystalline silicon fed in the feeding step between the first member and the second member, wherein in the driving step, at least one of the first member and the second member is driven so that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less.

[0008] According to one aspect of the present invention, it is possible to improve the yield of polycrystalline silicon having a desired particle size and to sufficiently reduce the amount of fine powder of polycrystalline silicon generated.

[0009] FIG. 1 is a schematic diagram showing an example of the configuration of a polycrystalline silicon crushing device according to an embodiment of the present invention. FIG. 1 is a diagram for explaining a first sensor provided in the crushing device shown in FIG. 1. FIG. 1 is a diagram for explaining the shortest distance between a first member and a second member in the crushing device shown in FIG. 1. FIG. 1 is a diagram for explaining a housing provided below the first member and the second member provided in the crushing device shown in FIG. 1. FIG. 1 is a schematic diagram showing an example of the configuration of a crushing device as a modified example 2 of the crushing device shown in FIG. 1. FIG. 1 is a graph showing the fine powder generation rate and yield according to Example 1 of the present invention. FIG. 1 is a graph showing the relationship between the filling rate and the ratio according to Example 2 of the present invention. FIG. 1 is a graph showing the relationship between the fine powder generation rate and the yield according to Example 3 of the present invention.

[0010] [Polycrystalline Silicon Crushing Apparatus] Fig. 1 is a schematic diagram showing an example of the configuration of an apparatus 1 for crushing polycrystalline silicon S according to one embodiment of the present invention. Fig. 2 is a diagram for explaining a first sensor 50 provided in the crushing apparatus 1 shown in Fig. 1. In Fig. 2, the drive unit 30, the control unit 60, the plate receiving unit 70, and the toggle plate T1 are omitted. The following description will explain the crushing apparatus 1, but also serves as a description of a method for crushing polycrystalline silicon S.

[0011] The crushing device 1 is a device that crushes polycrystalline silicon S and is called a jaw crusher. As shown in Fig. 1 , the crushing device 1 includes a first member 10, a second member 20, a drive unit 30, a conveyance unit 40, a first sensor 50, a control unit 60, a plate receiving unit 70, and a toggle plate T1.

[0012] (First Member and Second Member) The first member 10 is fixed at a predetermined position, and is fixed to a frame (not shown) provided in the crushing device 1. The first member 10 has fixed teeth 10a. The first member 10 and the second member 20 are used to crush the polycrystalline silicon S. The second member 20 is fixed to the driving unit 30, and is disposed so as to face the first member 10. The second member 20 has movable teeth 20a.

[0013] (Drive Unit) The drive unit 30 drives the second member 20 and crushes the polycrystalline silicon S by sandwiching the polycrystalline silicon S fed by the transport unit 40 between the first member 10 and the second member 20. The drive unit 30 has a rotation shaft 31, and the second member 20 is fixed to the rotation shaft 31. The drive unit 30 has a motor (not shown), and rotates the rotation shaft 31 using the motor to move the second member 20 with respect to the rotation shaft 31. In this way, the drive unit 30 drives the second member 20 so that the distance between the first member 10 and the second member 20 is changed.

[0014] The driving unit 30 drives the second member 20 so that the shortest distance D1 between the first member 10 and the second member 20 is 17 mm or more and 30 mm or less. Specifically, the shortest distance D1 is the distance between the first member 10 and the second member 20 when they are closest to each other. In other words, the driving unit 30 limits the range in which the rotating shaft 31 can rotate so that the shortest distance D1 is 17 mm or more and 30 mm or less.

[0015] In this way, the driving unit 30 drives the second member 20 so that the shortest distance D1 between the first member 10 and the second member 20 is 17 mm or more and 30 mm or less. This improves the yield of polycrystalline silicon S having a particle size of more than 8 mm and 50 mm or less, and reduces the amount of fine powder of polycrystalline silicon S having a particle size of 8 mm or less that is generated.

[0016] Such an effect also contributes to the achievement of, for example, Goal 12 of the Sustainable Development Goals (SDGs) advocated by the United Nations, "Ensure sustainable consumption and production patterns." Details of the effect of being able to improve the yield of polycrystalline silicon S and the effect of being able to reduce the amount of fine powder of polycrystalline silicon S generated will be described in Example 1 below.

[0017] Furthermore, as described above, when the first member 10 and the second member 20 are closest to each other, the shortest distance D1 between the first member 10 and the second member 20 is 17 mm or more and 30 mm or less. This makes it possible to further improve the yield of polycrystalline silicon S having a particle size of more than 8 mm and 50 mm or less, and to further reduce the amount of fine powder of polycrystalline silicon S having a particle size of 8 mm or less that is generated.

[0018] Fig. 3 is a diagram illustrating the shortest distance D1 between the first member 10 and the second member 20 in the crushing device 1 shown in Fig. 1. Fig. 3 is a diagram illustrating the fixed teeth 10a of the first member 10 and the movable teeth 20a of the second member 20 as viewed from above. As shown in Fig. 3, a plurality of peaks M1 and a plurality of valleys V1 are alternately formed on each of the fixed teeth 10a and the movable teeth 20a. The shortest distance D1 is the distance between the apex of the peak M1 on one of the fixed teeth 10a and the movable teeth 20a and the lowest position of the valley V1 facing the peak M1 on the other of the fixed teeth 10a and the movable teeth 20a.

[0019] (Conveying Unit) The conveying unit 40 conveys the polycrystalline silicon S, thereby injecting the polycrystalline silicon S from above between the first member 10 and the second member 20. The process in which the conveying unit 40 injects the polycrystalline silicon S is an example of an injecting process. The polycrystalline silicon S injected from the conveying unit 40 enters between the fixed teeth 10 a and the movable teeth 20 a, is crushed by the fixed teeth 10 a and the movable teeth 20 a, and falls downward through the gap between the fixed teeth 10 a and the movable teeth 20 a.

[0020] The conveying unit 40 may include, for example, a vibrating feeder (not shown) that conveys the polycrystalline silicon S by vibrating. The vibration of the vibrating feeder conveys the polycrystalline silicon S in a conveying direction F1. The conveying direction F1 is the direction from the conveying unit 40 toward the driving unit 30. The vibration of the vibrating feeder is controlled by the control unit 60.

[0021] The vibrating feeder vibrates in an obliquely upward direction relative to the conveying direction F1. Specifically, the vibration direction of the vibrating feeder is between the conveying direction F1 and a vertically upward direction perpendicular to the horizontal plane. The vibrating feeder is, for example, a vibrating feeder that vibrates using a vibrator, or an electromagnetic feeder that vibrates using an electromagnet.

[0022] By using the vibrating feeder as the conveying unit 40 that conveys the polycrystalline silicon S, it is easy to control the discharge of the polycrystalline silicon S to the outside of the conveying unit 40. Furthermore, since the vibrating feeder causes the plurality of polycrystalline silicon S to spread horizontally on the conveying unit 40, the amount of polycrystalline silicon S introduced between the first member 10 and the second member 20 can be kept as constant as possible.

[0023] 2 , the first sensor 50 is provided above the first member 10 and the second member 20. The first sensor 50 detects a distance D2 between the first sensor 50 and the polycrystalline silicon S sandwiched between the first member 10 and the second member 20. The first sensor 50 is, for example, a laser sensor having a light-emitting unit (not shown) that emits laser light L1 downward, and a light-receiving unit (not shown) that receives light L2 that is the laser light L1 reflected by the polycrystalline silicon S.

[0024] Specifically, the first sensor 50 may be a laser sensor that detects the distance D2 based on the period from when the light-emitting unit emits the laser light L1 to when the light-receiving unit receives the light L2. Alternatively, the first sensor 50 may be a triangulation laser sensor.

[0025] (Control Unit) The control unit 60 controls the driving of the drive unit 30 and the transport of the transport unit 40. The control unit 60 controls the driving of the transport unit 40 based on the detection result of the distance D2 by the first sensor 50. There is a negative correlation between the distance D2 detected by the first sensor 50 and the filling rate of the polycrystalline silicon S.

[0026] Specifically, the shorter the distance D2, the greater the filling rate of the polycrystalline silicon S, and the longer the distance D2, the smaller the filling rate of the polycrystalline silicon S. The filling rate of the polycrystalline silicon S is the ratio of the volume of the portion filled with the polycrystalline silicon S to the volume of the space SP1 between the fixed tooth 10 a and the movable tooth 20 a.

[0027] The control unit 60 determines whether the distance D2 detected by the first sensor 50 is equal to or greater than a predetermined value. If the control unit 60 determines that the distance D2 detected by the first sensor 50 is equal to or greater than the predetermined value, the control unit 60 continues to drive the conveying unit 40, that is, continues to vibrate the vibrating feeder.

[0028] On the other hand, when the control unit 60 determines that the distance D2 detected by the first sensor 50 is less than the predetermined value, the control unit 60 stops driving the conveying unit 40, that is, stops the vibration of the vibrating feeder. The control unit 60 controls the driving of the conveying unit 40 based on the detection result of the first sensor 50, thereby enabling accurate control of the filling rate of the polycrystalline silicon S.

[0029] Furthermore, the control unit 60 continues driving the drive unit 30 while controlling the driving of the transport unit 40. As a result, while the transport by the transport unit 40 is stopped, the polycrystalline silicon S is crushed by the first member 10 and the second member 20 and falls downward from the gap between the first member 10 and the second member 20, thereby reducing the filling rate of the polycrystalline silicon S. If the distance D2 becomes equal to or greater than the predetermined value after the control unit 60 has stopped driving the transport unit 40, the control unit 60 resumes driving the transport unit 40.

[0030] In this way, the control unit 60 controls the driving of the transport unit 40 based on the detection result of the first sensor 50, which detects the distance D2 between the polycrystalline silicon S sandwiched between the first member 10 and the second member 20 and the first sensor 50. This makes it possible to precisely control the amount of polycrystalline silicon S sandwiched between the first member 10 and the second member 20.

[0031] Therefore, it is possible to control the amount of polycrystalline silicon S sandwiched between the first member 10 and the second member 20 so as to improve the yield of polycrystalline silicon S of a desired size and reduce the amount of fine powder of polycrystalline silicon S. Details of the effect of improving the yield of polycrystalline silicon S and reducing the amount of fine powder of polycrystalline silicon S will be described in Example 2 below.

[0032] (Plate Receiving Portion and Toggle Plate) A toggle plate T1 is connected to the lower portion of the second member 20 on the side opposite to the movable tooth 20a. The toggle plate T1 connects the lower portion of the second member 20 and the plate receiving portion 70 so that they can move relative to each other. The crushing device 1 is a single-toggle type device equipped with one toggle plate T1. The plate receiving portion 70 is fixed to the frame described above.

[0033] (Housing) Fig. 4 is a diagram illustrating a housing 80 provided below the first member 10 and the second member 20 included in the crushing device 1 shown in Fig. 1. The drive unit 30, the transport unit 40, the first sensor 50, the control unit 60, the plate receiving unit 70, and the toggle plate T1 are omitted from Fig. 4. As shown in Fig. 4, the crushing device 1 may further include housings 80 and 81, a detector 82, and a second sensor 83.

[0034] The housing 80 is provided below the first member 10 and the second member 20, and forms a space SP2 in which polycrystalline silicon S crushed by the first member 10 and the second member 20 accumulates. The polycrystalline silicon S that falls downward from the gap between the first member 10 and the second member 20 accumulates in the space SP2. The housing 80 is made of, for example, resin, and is formed in a box shape that is open at the top.

[0035] In this way, the polycrystalline silicon S crushed by the first member 10 and the second member 20 is deposited in the space SP2 formed by the housing 80, and therefore, of the polycrystalline silicon S deposited in the housing 80, there is polycrystalline silicon S that does not come into contact with the housing 80. Therefore, it is possible to reduce contact of the polycrystalline silicon S with other members, and it is possible to reduce surface contamination of the polycrystalline silicon S.

[0036] Furthermore, by accumulating polycrystalline silicon S on the housing 80, when polycrystalline silicon S has accumulated on the housing 80, polycrystalline silicon S that falls downward from the first member 10 and the second member 20 collides with polycrystalline silicon S that has already accumulated on the housing 80, and does not collide with the bottom surface 80a of the housing 80. Therefore, it is possible to reduce contact of polycrystalline silicon S with the housing 80, and it is possible to reduce contamination of the surface of the polycrystalline silicon S with resin.

[0037] The housing 81 is connected to the side of the housing 80, and the interior of the housing 81 is in communication with the interior of the housing 80. In other words, the space SP3 formed by the housing 81 is in communication with the space SP2 formed by the housing 80. The polycrystalline silicon S that flows from the space SP2 into the space SP3 enters the space SP3. The housing 81 is made of, for example, resin, and is formed in a box shape with an open bottom. The polycrystalline silicon S that falls from below the housing 81 is placed on the detector 82. The housing 81 extends downward beyond the bottom surface 80a of the housing 80.

[0038] (Second Sensor) The second sensor 83 is provided inside the housing 80 and detects whether the polycrystalline silicon S deposited inside the housing 80 has reached a predetermined height H1 from the bottom surface 80a of the housing 80. The second sensor 83 may be the same sensor as the first sensor 50. A light-emitting unit included in the second sensor 83 emits, for example, laser light in the horizontal direction, and a light-receiving unit included in the second sensor 83 receives light that is the laser light emitted from the light-emitting unit and reflected by the polycrystalline silicon S. When the light-receiving unit receives light, the second sensor 83 detects that the polycrystalline silicon S has reached the predetermined height H1.

[0039] When the second sensor 83 detects that the polycrystalline silicon S deposited inside the housing 80 has reached a predetermined height H1, the control unit 60 stops driving the transport unit 40. This prevents the polycrystalline silicon S from continuing to deposit inside the housing 80, and prevents the polycrystalline silicon S from clogging the inside of the housing 80. It also prevents a portion of the polycrystalline silicon S from being exposed outside the housing 80, and prevents the polycrystalline silicon S from coming into contact with members outside the housing 80. This reduces surface contamination of the polycrystalline silicon S.

[0040] Specifically, it is possible to prevent the polycrystalline silicon S from continuing to accumulate inside the housing 80, thereby reducing the possibility of hanging inside the housing 80. In addition, it is possible to prevent a portion of the polycrystalline silicon S from being exposed to the outside of the housing 80, thereby preventing the polycrystalline silicon S from coming into contact with the first member 10 or the second member 20.

[0041] (Detector) The detector 82 is, for example, a metal detector that detects the presence of an object containing metal. The detector 82 detects the polycrystalline silicon S that has fallen from below the housing 81 and is placed on the detector 82. The detector 82 also functions as a mounting table on which the polycrystalline silicon S can be placed.

[0042] The detector 82 may be configured to supply the polycrystalline silicon S from a first position to a second position and to be movable between the first position and the second position. The first position is a position where the polycrystalline silicon S dropping from below the housing 81 can be placed. The second position is a position away from the first position, and is, for example, a position to which the polycrystalline silicon S is supplied.

[0043] The movement of the detector 82 may be controlled by the control unit 60. The detector 82 places the polycrystalline silicon S that has fallen from below the housing 81 at the first position, and supplies the polycrystalline silicon S to the second position. Furthermore, the polycrystalline silicon S may be removed from the detector 82 at the second position. Once the polycrystalline silicon S is removed, the detector 82 returns from the second position to the first position.

[0044] [Variation 1] The driving unit 30 may drive at least one of the first member 10 and the second member 20. In this case, the driving unit 30 crushes the polycrystalline silicon S by sandwiching the polycrystalline silicon S between the first member 10 and the second member 20. The driving unit 30 also drives at least one of the first member 10 and the second member 20 so that the shortest distance D1 is 17 mm or more and 30 mm or less. The process in which the driving unit 30 drives at least one of the first member 10 and the second member 20 is an example of a driving process.

[0045] For example, the driving unit 30 may drive only the first member 10 out of the first member 10 and the second member 20. In this case, the first member 10 is fixed to the driving unit 30, and the second member 20 is fixed to the frame described above.

[0046] Furthermore, the driving unit 30 may drive both the first member 10 and the second member 20. In this case, the first member 10 is fixed to a rotation shaft different from the rotation shaft 31 shown in Fig. 1 , and the second member 20 is fixed to the rotation shaft 31. The driving unit 30 has the different rotation shaft, rotates the different rotation shaft using a motor (not shown), and moves the first member 10 based on the different rotation shaft.

[0047] [Variation 2] Fig. 5 is a schematic diagram showing an example of the configuration of a crushing device 1D as Variation 2 of the crushing device 1 shown in Fig. 1. As shown in Fig. 5, the crushing device 1D includes a first member 10D, a second member 20D, a drive unit 30D, a plate receiving unit 70D, toggle plates T2 and T3, and a support unit TS. The crushing device 1D further includes the transport unit 40, first sensor 50, and control unit 60 shown in Fig. 1. The crushing device 1D may also include housings 80 and 81, a detector 82, and a second sensor 83 shown in Fig. 4.

[0048] The first member 10D is the same as the first member 10, the second member 20D is the same as the second member 20, and the drive unit 30D is the same as the drive unit 30. A toggle plate T2 is connected to the lower part of the second member 20D. The toggle plate T2 connects the lower part of the second member 20D and the support unit TS so that they can move relative to each other. The support unit TS is fixed to a frame provided in the crushing device 1D.

[0049] The toggle plate T3 connects the plate receiving portion 70D and the support portion TS so as to be movable relative to each other. The plate receiving portion 70D is fixed to the above-mentioned frame provided in the crushing device 1D. The crushing device 1D is a double-toggle type device provided with two toggle plates T2, T3. The crushing device 1D can reduce the amount of fine powder of polycrystalline silicon S generated compared to the crushing device 1D, but the crushing device 1D may also be included in the technical scope of the present invention.

[0050] 6 is a graph showing the fine powder generation rate and yield according to Example 1 of the present invention. In Example 1, the polycrystalline silicon S was crushed by changing the shortest distance D1 between the first member 10 and the second member 20 in the crushing device 1 shown in FIG.

[0051] 6, the horizontal axis represents the shortest distance D1 [mm], and the vertical axis represents the fine powder generation rate [%]. The fine powder generation rate is the ratio of the amount of fine powder of polycrystalline silicon S having a particle size of 8 mm or less to the amount of polycrystalline silicon S introduced between first member 10 and second member 20.

[0052] 6, the horizontal axis represents the shortest distance D1 [mm], and the vertical axis represents the yield [%]. The yield is the ratio of the amount of polycrystalline silicon S having a particle size of 50 mm or less to the amount of polycrystalline silicon S introduced between the first member 10 and the second member 20.

[0053] The inventors conducted extensive research into the minimum distance D1 in relation to the results shown in the graphs denoted by reference numerals 601 and 602 in Fig. 6. As a result, the inventors found a numerical range RA for the minimum distance D1 that maximizes the yield of polycrystalline silicon S having an optimal particle size while minimizing the rate of fine powder generation. Here, the optimal particle size is a size greater than 8 mm and equal to or less than 50 mm. The numerical range RA is equal to or greater than 17 mm and equal to or less than 30 mm.

[0054] [Example 2] Fig. 7 is a graph showing the relationship between the filling rate and the ratio according to Example 2 of the present invention. In Example 2, the above-described filling rate of polycrystalline silicon S was changed to crush polycrystalline silicon S in the crushing device 1 shown in Fig. 1. In the graph shown in Fig. 7, the horizontal axis represents the filling rate [%], and the vertical axis represents the ratio [%] of the amount of specific polycrystalline silicon S to the amount of polycrystalline silicon S introduced between the first member 10 and the second member 20.

[0055] 7, graph G1 shows the ratio of the amount of fine powder of polycrystalline silicon S having a particle size of 8 mm or less to the amount of charged polycrystalline silicon S. Graph G2 shows the ratio of the amount of polycrystalline silicon S having a particle size of 50 mm or less to the amount of charged polycrystalline silicon S. Graph G3 shows the ratio of the amount of polycrystalline silicon S having a particle size greater than 50 mm to the amount of charged polycrystalline silicon S.

[0056] 7, as the filling rate increases, the proportion of the amount of polycrystalline silicon S having a particle size of 50 mm or less increases, while the proportion of the amount of fine powder of polycrystalline silicon S having a particle size of 8 mm or less also increases. Therefore, if the filling rate increases too much, multiple pieces of polycrystalline silicon S collide with each other, causing cracks and being crushed into smaller pieces than necessary.

[0057] 7, it is preferable to control the filling rate in order to reduce the amount of fine powder generated while increasing the amount of polycrystalline silicon S having a particle size of 50 mm or less. Therefore, as described above, it is preferable that control unit 60 controls the driving of conveying unit 40 based on the detection result of distance D2 by first sensor 50.

[0058] Example 3 Fig. 8 is a graph showing the relationship between the fine powder generation rate and the yield according to Example 3 of the present invention. In Example 3, polycrystalline silicon S was crushed using the single-toggle type crushing device 1 shown in Fig. 1 and the double-toggle type crushing device 1D shown in Fig. 5. In the graph shown in Fig. 8, the horizontal axis represents the fine powder generation rate [%], and the vertical axis represents the yield [%]. The definitions of the fine powder generation rate and the yield in Fig. 8 are the same as those defined in Example 1.

[0059] 8, graph G4 shows the yield when crushing polycrystalline silicon S using the crusher 1, and graph G5 shows the yield when crushing polycrystalline silicon S using the crusher 1D. As shown in FIG. 8, when the crusher 1 was used, the yield tended to be higher and the fine powder generation rate lower than when the crusher 1D was used. Therefore, the crusher 1 can improve the yield of polycrystalline silicon S and reduce the amount of fine powder generated compared to the crusher 1D.

[0060] [Example of implementation by software] The functions of the crushing device 1, 1D (hereinafter referred to as the "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as the control block (control unit 60) of the device.

[0061] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The functions described in each of the above embodiments are realized by executing the program using the control device and storage device.

[0062] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0063] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0064] [Summary] The polycrystalline silicon crushing device according to aspect 1 of the present invention comprises a first member, a second member arranged to face the first member, and a drive unit that drives at least one of the first member and the second member to crush the polycrystalline silicon by sandwiching the polycrystalline silicon between the first member and the second member, and the drive unit drives at least one of the first member and the second member so that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less.

[0065] The drive unit drives at least one of the first member and the second member so that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less, thereby improving the yield of polycrystalline silicon having a particle size of more than 8 mm and 50 mm or less and reducing the amount of polycrystalline silicon fine powder having a particle size of 8 mm or less.

[0066] The polycrystalline silicon crushing device according to aspect 2 of the present invention may be the same as in aspect 1, further comprising: a conveying unit that conveys the polycrystalline silicon from above between the first member and the second member; a first sensor provided above the first member and the second member that detects the distance between the polycrystalline silicon sandwiched between the first member and the second member and the first sensor; and a control unit that controls the driving of the conveying unit based on the detection result of the distance by the first sensor.

[0067] The control unit controls the driving of the conveying unit based on the detection result of the first sensor, which detects the distance between the polycrystalline silicon sandwiched between the first and second members and the first sensor. This makes it possible to accurately control the amount of polycrystalline silicon sandwiched between the first and second members. Therefore, it is possible to control the amount of polycrystalline silicon sandwiched between the first and second members so as to improve the yield of polycrystalline silicon of a desired size and reduce the amount of polycrystalline silicon powder generated.

[0068] The polycrystalline silicon crushing device according to aspect 3 of the present invention may be the same as in aspect 1 or 2, and further include a housing provided below the first member and the second member, forming a space in which the polycrystalline silicon crushed by the first member and the second member is deposited.

[0069] Since the polycrystalline silicon crushed by the first and second members is deposited in the space defined by the housing, some of the polycrystalline silicon deposited on the housing does not come into contact with the housing, thereby reducing contact of the polycrystalline silicon with other members and reducing surface contamination of the polycrystalline silicon.

[0070] The polycrystalline silicon crushing device according to aspect 4 of the present invention may be any of aspects 1 to 3, further comprising: a conveying unit that conveys the polycrystalline silicon from above between the first member and the second member; a second sensor provided inside the housing that detects whether the polycrystalline silicon accumulated inside the housing has reached a predetermined height from the bottom surface of the housing; and a control unit that stops driving the conveying unit when the second sensor detects that the polycrystalline silicon accumulated inside the housing has reached the predetermined height.

[0071] The control unit stops driving the transport unit when the second sensor detects that the polycrystalline silicon accumulating inside the housing has reached a predetermined height. This prevents the polycrystalline silicon from continuing to accumulate inside the housing, and prevents the polycrystalline silicon from clogging the inside of the housing. It also prevents a portion of the polycrystalline silicon from being exposed outside the housing, and prevents the polycrystalline silicon from coming into contact with components outside the housing. This reduces surface contamination of the polycrystalline silicon.

[0072] In the polycrystalline silicon crushing device according to Aspect 5 of the present invention, in any one of Aspects 1 to 4, the shortest distance may be the distance between the first member and the second member when they are closest to each other.

[0073] When the first member and the second member are closest to each other, the shortest distance between them is 17 mm or more and 30 mm or less, which can further improve the yield of polycrystalline silicon having a particle size of more than 8 mm and 50 mm or less, and can further reduce the amount of polycrystalline silicon fine powder having a particle size of 8 mm or less.

[0074] A method for crushing polycrystalline silicon according to aspect 6 of the present invention includes a feeding step of feeding polycrystalline silicon between a first member and a second member arranged opposite the first member, and a driving step of driving at least one of the first member and the second member to crush the polycrystalline silicon by sandwiching the polycrystalline silicon fed in the feeding step between the first member and the second member, wherein in the driving step, at least one of the first member and the second member is driven so that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less.

[0075] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Configurations obtained by appropriately combining multiple technical means disclosed in the embodiments are also included in the technical scope of the present invention.

[0076] 1, 1D Crushing device 10, 10D First member 20, 20D Second member 30, 30D Driving unit 40 Conveying unit 50 First sensor 60 Control unit 80 Housing 80a Bottom surface 83 Second sensor D1 Shortest distance D2 Distance F1 Conveying direction S Polycrystalline silicon SP2 Space

Claims

1. A polycrystalline silicon crushing device comprising: a first member; a second member arranged to face the first member; and a drive unit that drives at least one of the first member and the second member to crush the polycrystalline silicon by sandwiching the polycrystalline silicon between the first member and the second member, wherein the drive unit drives at least one of the first member and the second member so that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less.

2. The polycrystalline silicon crushing device described in claim 1, further comprising: a transport unit that transports the polycrystalline silicon from above between the first member and the second member; a first sensor provided above the first member and the second member that detects the distance between the polycrystalline silicon sandwiched between the first member and the second member and the first sensor; and a control unit that controls the operation of the transport unit based on the detection result of the distance by the first sensor.

3. The polycrystalline silicon crushing device as described in claim 1, further comprising a housing provided below the first member and the second member and forming a space in which the polycrystalline silicon crushed by the first member and the second member is accumulated.

4. The polycrystalline silicon crushing device described in claim 3, further comprising: a transport unit that transports the polycrystalline silicon from above between the first member and the second member; a second sensor provided inside the housing that detects whether the polycrystalline silicon accumulated inside the housing has reached a predetermined height from the bottom surface of the housing; and a control unit that stops driving the transport unit when the second sensor detects that the polycrystalline silicon accumulated inside the housing has reached the predetermined height.

5. The polycrystalline silicon crushing device according to claim 1, wherein the shortest distance is the distance between the first member and the second member when they are closest to each other.

6. A method for crushing polycrystalline silicon comprising: a feeding step of feeding polycrystalline silicon between a first member and a second member arranged to face the first member; and a drive step of driving at least one of the first member and the second member to crush the polycrystalline silicon by sandwiching the polycrystalline silicon fed in the feeding step between the first member and the second member, characterized in that in the drive step, at least one of the first member and the second member is driven so that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less.

Images