Apparatus for crushing polycrystalline silicon and method for crushing polycrystalline silicon

Abstract

The goal is to improve the yield of polycrystalline silicon of the desired particle size while significantly reducing the amount of fine polycrystalline silicon powder generated. [Solution] The polycrystalline silicon (S) crushing device (1) includes a drive unit (30) that crushes the polycrystalline silicon (S) by sandwiching it between a first member (10) and a second member (20), and the drive unit (30) drives at least one of the first member (10) and the second member (20) such 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.

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the shortest gap between the fixed blade and the movable blade disclosed in Patent Document 1, there is a problem that the amount of fine powder of polycrystalline silicon generated increases, and the yield of polycrystalline silicon having a desired particle size cannot be sufficiently increased.

[0005] One aspect of the present invention aims 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.

Means for Solving the Problems

[0006] To solve the above problems, a polycrystalline silicon crushing apparatus according to one aspect of the present invention comprises a first member, a second member arranged opposite to 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 it between the first member and the second member, wherein the drive unit drives at least one of the first member and the second member such 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 to 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 fed in the feeding step by sandwiching it 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 such that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less. [Effects of the Invention]

[0008] According to one aspect of the present invention, the yield of polycrystalline silicon of a desired particle size can be improved, while the amount of fine polycrystalline silicon powder generated can be sufficiently reduced. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing an example of the configuration of a polycrystalline silicon crushing apparatus according to one embodiment of the present invention. [Figure 2] This diagram illustrates the first sensor included in the crushing device shown in Figure 1. [Figure 3] This diagram illustrates the shortest distance between the first and second members in the crushing device shown in Figure 1. [Figure 4]This figure illustrates the housing located below the first and second members of the crushing device shown in Figure 1. [Figure 5] This 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 Figure 1. [Figure 6] This graph shows the fine powder generation rate and yield according to Example 1 of the present invention. [Figure 7] This graph shows the relationship between the filling rate and the ratio according to Example 2 of the present invention. [Figure 8] This graph shows the relationship between the fine powder generation rate and the yield according to Example 3 of the present invention. [Modes for carrying out the invention]

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

[0011] The crushing device 1 is a device for crushing polycrystalline silicon S and is called a jaw crusher. As shown in Figure 1, the crushing device 1 comprises a first member 10, a second member 20, a drive unit 30, a transport 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 in a predetermined position and is fixed to a frame (not shown) provided by the crushing device 1. The first member 10 has fixed teeth 10a. The first member 10 and the second member 20 are used for crushing polycrystalline silicon S. The second member 20 is fixed to the drive unit 30 and is positioned opposite 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 by sandwiching the polycrystalline silicon S introduced by the conveying unit 40 between the first member 10 and the second member 20, the polycrystalline silicon S is crushed. The drive unit 30 has a rotating shaft 31, and the second member 20 is fixed to the rotating shaft 31. The drive unit 30 has a motor (not shown), rotates the rotating shaft 31 by the motor, and moves the second member 20 with reference to the rotating 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 drive 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 in the state where the first member 10 and the second member 20 are closest to each other. That is, in the drive unit 30, the range in which the rotating shaft 31 can rotate is limited so that the shortest distance D1 is 17 mm or more and 30 mm or less.

[0015] In this way, the drive 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. Thereby, the yield of the polycrystalline silicon S having a particle size larger than 8 mm and 50 mm or less can be improved, and the amount of fine powder of the polycrystalline silicon S having a particle size of 8 mm or less generated can be reduced.

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

[0017] Also, as described above, in the state where 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. Thereby, the yield of the polycrystalline silicon S having a particle size larger than 8 mm and 50 mm or less can be further improved, and the amount of fine powder of the polycrystalline silicon S having a particle size of 8 mm or less generated can be further reduced.

[0018] FIG. 3 is a view for explaining the shortest distance D1 between the first member 10 and the second member 20 in the crushing device 1 shown in FIG. 1. Further, FIG. 3 is a view of 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 crest portions M1 and a plurality of trough portions V1 are alternately formed on the fixed teeth 10a and the movable teeth 20a, respectively. The shortest distance D1 is the distance between the apex of one of the crest portions M1 of the fixed teeth 10a and the movable teeth 20a and the lowest position of the trough portion V1 of the other of the fixed teeth 10a and the movable teeth 20a that faces the one crest portion M1.

[0019] (Conveying section) The conveying section 40 conveys the polycrystalline silicon S and thereby inputs the polycrystalline silicon S from above between the first member 10 and the second member 20. The step of the conveying section 40 inputting the polycrystalline silicon S is an example of the inputting step. The polycrystalline silicon S input from the conveying section 40 enters between the fixed teeth 10a and the movable teeth 20a, is crushed by the fixed teeth 10a and the movable teeth 20a, and falls downward from the gap between the fixed teeth 10a and the movable teeth 20a.

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

[0021] The vibrating feeder described above vibrates diagonally upward with respect to the transport direction F1. Specifically, the direction of vibration of the vibrating feeder is between the transport direction F1 and the vertically upward direction perpendicular to the horizontal plane. The vibrating feeder described above 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 transport section 40 for transporting polycrystalline silicon S, it is easier to control the discharge of polycrystalline silicon S to the outside of the transport section 40. Furthermore, because the vibrating feeder causes multiple polycrystalline silicon S to spread horizontally on the transport section 40, the amount of polycrystalline silicon S fed between the first member 10 and the second member 20 can be kept as constant as possible.

[0023] (Sensor 1) As shown in Figure 2, the first sensor 50 is provided above the first member 10 and the second member 20. The first sensor 50 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. The first sensor 50 is a laser sensor having, for example, a light-emitting unit (not shown) that emits laser light L1 downwards, and a light-receiving unit (not shown) that receives light L2 reflected by the polycrystalline silicon S from the laser light L1.

[0024] Specifically, the first sensor 50 may be a laser sensor that detects distance D2 based on the period from the time the light-emitting unit emits laser light L1 to the time the light-receiving unit receives light L2. Alternatively, the first sensor 50 may be a triangulation-type 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 distance D2 detected by the first sensor 50. There is a negative correlation between the distance D2 detected by the first sensor 50 and the packing density of the polycrystalline silicon S.

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

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

[0028] On the other hand, if the control unit 60 determines that the distance D2 detected by the first sensor 50 is less than the predetermined value, it stops driving the transport unit 40, that is, it stops the vibration of the vibrating feeder. By controlling the driving of the transport unit 40 based on the detection result of the first sensor 50, the control unit 60 can accurately control the filling rate of the polycrystalline silicon S.

[0029] Furthermore, the control unit 60 continues to drive the drive unit 30 while controlling the drive of the transport unit 40. As a result, while 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 through the gap between the first member 10 and the second member 20, thus reducing the filling rate of the polycrystalline silicon S. If the distance D2 becomes greater than or equal to the predetermined value after the drive of the transport unit 40 has been stopped, the control unit 60 restarts the drive of the transport unit 40.

[0030] In this manner, the control unit 60 controls the drive 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 accurately control the amount of polycrystalline silicon S sandwiched between the first member 10 and the second member 20.

[0031] Therefore, the amount of polycrystalline silicon S sandwiched between the first member 10 and the second member 20 can be controlled to improve the yield of polycrystalline silicon S of the desired size and reduce the amount of fine polycrystalline silicon S powder generated. Details of the effect of improving the yield of polycrystalline silicon S and reducing the amount of fine polycrystalline silicon S powder generated will be explained in Example 2 below.

[0032] (Plate receiving section and toggle plate) A toggle plate T1 is connected to the lower part of the second member 20 on the side opposite to the movable teeth 20a. The toggle plate T1 connects the lower part 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] (Enclosure) Figure 4 is a diagram illustrating the housing 80 provided below the first member 10 and the second member 20 of the crushing device 1 shown in Figure 1. In Figure 4, the drive unit 30, the conveying unit 40, the first sensor 50, the control unit 60, the plate receiving unit 70, and the toggle plate T1 are omitted. As shown in Figure 4, the crushing device 1 may further include housings 80, 81, a detector 82, and a second sensor 83.

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

[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. Therefore, some of the polycrystalline silicon S deposited on the housing 80 does not come into contact with the housing 80. Thus, contact between the polycrystalline silicon S and other members can be reduced, and surface contamination of the polycrystalline silicon S can be reduced.

[0036] Furthermore, as polycrystalline silicon S accumulates on the housing 80, when polycrystalline silicon S is deposited on the housing 80, the polycrystalline silicon S that falls downward from the first member 10 and the second member 20 will collide with the polycrystalline silicon S already deposited on the housing 80, and will not collide with the bottom surface 80a of the housing 80. Therefore, contact between the polycrystalline silicon S and the housing 80 can be reduced, and contamination of the surface of the polycrystalline silicon S with resin can be reduced.

[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. Polycrystalline silicon S flows into space SP3 from space SP2. The housing 81 is made of, for example, resin and is formed in a box shape with the bottom open. Polycrystalline silicon S that falls from the bottom of the housing 81 is placed on top of the detector 82. The housing 81 extends below the bottom surface 80a of the housing 80.

[0038] (Second sensor) The second sensor 83 is installed 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. The light-emitting part of the second sensor 83 emits, for example, laser light in the horizontal direction, and the light-receiving part of the second sensor 83 receives the light reflected by the polycrystalline silicon S from the laser light emitted from the light-emitting part. When the light-receiving part receives light, the second sensor 83 detects that the polycrystalline silicon S has reached a predetermined height H1.

[0039] When the second sensor 83 detects that the polycrystalline silicon S accumulating 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 accumulate inside the housing 80 and prevents it from becoming clogged. It also prevents a portion of the polycrystalline silicon S from being exposed to the outside of the housing 80 and prevents the polycrystalline silicon S from coming into contact with external components of the housing 80. Therefore, surface contamination of the polycrystalline silicon S can be reduced.

[0040] Specifically, this prevents polycrystalline silicon S from continuously accumulating inside the housing 80, thereby reducing the possibility of shelf-hanging occurring inside the housing 80. Furthermore, it prevents a portion of the polycrystalline silicon S from being exposed to the outside of the housing 80, thus 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 polycrystalline silicon S that has fallen from below the housing 81 and is placed on top of the detector 82. The detector 82 also functions as a mounting platform on which polycrystalline silicon S can be placed.

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

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

[0044] [Variation 1] The drive unit 30 may drive at least one of the first member 10 and the second member 20. In this case, the drive unit 30 crushes the polycrystalline silicon S by sandwiching it between the first member 10 and the second member 20. The drive 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 step of the drive unit 30 driving at least one of the first member 10 and the second member 20 is an example of a driving step.

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

[0046] Furthermore, the drive 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 other than the rotation shaft 31 shown in Figure 1, and the second member 20 is fixed to the rotation shaft 31. The drive unit 30 has the other rotation shaft and rotates the other rotation shaft with a motor (not shown), and moves the first member 10 with respect to the other rotation shaft.

[0047] [Variation 2] Figure 5 is a schematic diagram showing an example of the configuration of a crushing device 1D, which is a modified example 2 of the crushing device 1 shown in Figure 1. As shown in Figure 5, the crushing device 1D comprises a first member 10D, a second member 20D, a drive unit 30D, a plate receiving unit 70D, toggle plates T2, T3, and a support unit TS. The crushing device 1D further comprises a transport unit 40, a first sensor 50, and a control unit 60 as shown in Figure 1. The crushing device 1D may also further comprise housings 80, 81, a detector 82, and a second sensor 83 as shown in Figure 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 the frame of 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 frame described above, which is provided by the crushing device 1D. The crushing device 1D is a double-toggle type device equipped with two toggle plates T2 and T3. The crushing device 1 can reduce the amount of fine polycrystalline silicon S powder generated compared to the crushing device 1D, but the crushing device 1D may also be included within the technical scope of the present invention.

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

[0051] In the graph shown by reference numeral 601 in Figure 6, the horizontal axis represents the shortest interval D1 [mm], and the vertical axis represents the fine particle generation rate [%]. This fine particle generation rate is the ratio of the amount of fine polycrystalline silicon S with a particle size of 8 mm or less generated to the amount of polycrystalline silicon S introduced between the first member 10 and the second member 20.

[0052] In the graph shown by reference numeral 602 in Figure 6, the horizontal axis represents the shortest interval D1 [mm], and the vertical axis represents the yield [%]. The yield is the ratio of the amount of polycrystalline silicon S with 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] Regarding the results shown in the graphs labeled 601 and 602 in Figure 6, the inventors diligently researched the shortest interval D1. As a result, the inventors found a numerical range RA for the shortest interval D1 that maximizes the yield of polycrystalline silicon S with the optimal particle size while minimizing the generation rate of fine particles. Here, the optimal particle size is greater than 8 mm and less than or equal to 50 mm. The numerical range RA is between 17 mm and 30 mm.

[0054] [Example 2] Figure 7 is a graph showing the relationship between the packing rate and the ratio in Example 2 of the present invention. In Example 2, the polycrystalline silicon S was crushed in the crushing apparatus 1 shown in Figure 1 by changing the packing rate of the polycrystalline silicon S described above. In the graph shown in Figure 7, the horizontal axis represents the packing rate [%], and the vertical axis represents the ratio [%] of the amount of a specific polycrystalline silicon S to the amount of polycrystalline silicon S introduced between the first member 10 and the second member 20.

[0055] Furthermore, in the graphs shown in Figure 7, graph G1 shows the ratio of the amount of fine polycrystalline silicon S with a particle size of 8 mm or less to the amount of polycrystalline silicon S introduced. Graph G2 shows the ratio of the amount of polycrystalline silicon S with a particle size of 50 mm or less to the amount of polycrystalline silicon S introduced. Graph G3 shows the ratio of the amount of polycrystalline silicon S with a particle size larger than 50 mm to the amount of polycrystalline silicon S introduced.

[0056] As shown in Figure 7, as the packing density increases, the proportion of polycrystalline silicon S with a particle size of 50 mm or less increases, while the proportion of fine polycrystalline silicon S with a particle size of 8 mm or less also increases. Therefore, if the packing density increases too much, multiple polycrystalline silicon S particles collide with each other, causing cracks to occur and the material to be broken into smaller pieces than necessary.

[0057] As shown in the graph in Figure 7, it is preferable to control the packing rate in order to increase the amount of polycrystalline silicon S with a particle size of 50 mm or less while reducing the amount of fine powder generated. Therefore, as described above, it is preferable for the control unit 60 to control the drive of the transport unit 40 based on the distance D2 detection result by the first sensor 50.

[0058] [Example 3] Figure 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 Figure 1 and the double-toggle type crushing device 1D shown in Figure 5. In the graph shown in Figure 8, the horizontal axis shows the fine powder generation rate [%] and the vertical axis shows the yield [%]. The definitions of the fine powder generation rate and yield in Figure 8 are the same as those defined in Example 1.

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

[0060] [Examples of implementation using software] The function 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 by 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., memory) as hardware for executing the program. By executing the program using this control device and storage device, the functions described in each of the embodiments are realized.

[0062] The above program may be recorded on one or more computer-readable recording media, not temporary ones. These recording media may or may not be provided by the above device. In the latter case, the program may be supplied to the above device via any wired or wireless transmission medium.

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

[0064] 〔summary〕 A polycrystalline silicon crushing apparatus according to embodiment 1 of the present invention comprises a first member, a second member arranged opposite to 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 such 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 minimum distance between the first member and the second member is between 17 mm and 30 mm. This improves the yield of polycrystalline silicon with a particle size greater than 8 mm and 50 mm or less, while reducing the amount of fine polycrystalline silicon powder with a particle size of 8 mm or less that is generated.

[0066] A polycrystalline silicon crushing apparatus according to embodiment 2 of the present invention may further include, in embodiment 1, 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 distance detection result by the first sensor.

[0067] The control unit controls the drive of the transport 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 allows for precise control of the amount of polycrystalline silicon sandwiched between the first and second members. Therefore, the amount of polycrystalline silicon sandwiched between the first and second members can be controlled to improve the yield of polycrystalline silicon of the desired size and reduce the amount of fine polycrystalline silicon powder generated.

[0068] The polycrystalline silicon crushing apparatus according to embodiment 3 of the present invention may further include a housing provided below the first member and the second member, which forms a space for the polycrystalline silicon crushed by the first member and the second member to be deposited, in embodiment 1 or 2.

[0069] Since the polycrystalline silicon crushed by the first and second components is deposited in the space formed by the housing, some of the polycrystalline silicon deposited on the housing does not come into contact with the housing. Therefore, contact between the polycrystalline silicon and other components can be reduced, and surface contamination of the polycrystalline silicon can be reduced.

[0070] A polycrystalline silicon crushing apparatus according to embodiment 4 of the present invention may further include, in any of embodiments 1 to 3, 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 deposited 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 deposited inside the housing has reached the predetermined height.

[0071] The control unit stops the drive of 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 it from clogging the inside of the housing. It also prevents a portion of the polycrystalline silicon from being exposed to the outside of the housing and prevents the polycrystalline silicon from coming into contact with external components of the housing. Therefore, surface contamination of the polycrystalline silicon can be reduced.

[0072] In the polycrystalline silicon crushing apparatus according to embodiment 5 of the present invention, in any of embodiments 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 and second members are in their closest proximity, the shortest distance between them is between 17 mm and 30 mm. This improves the yield of polycrystalline silicon with particle sizes greater than 8 mm and 50 mm or less, while also reducing the amount of fine polycrystalline silicon powder generated with particle sizes 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 to 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 fed in the feeding step by sandwiching it 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 such 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 embodiments described above, and various modifications are possible within the scope of the claims. Configurations obtained by appropriately combining the multiple technical means disclosed in the embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0076] 1. 1D Crushing device 10, 10D First Member 20, 20D Second member 30, 30D drive unit 40 Conveying section 50 First Sensor 60 Control Unit 80 cabinets 80a Bottom 83 Second Sensor D1 Shortest interval D2 distance F1 Conveying direction S Polycrystalline silicon SP2 Space

Claims

1. First member and A second member is positioned opposite the first member, The device comprises a drive unit that drives at least one of the first member and the second member, and crushes the polycrystalline silicon by sandwiching it between the first member and the second member, The crushing apparatus for polycrystalline silicon is characterized in that the drive unit drives at least one of the first member and the second member such that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less.

2. A conveying unit for conveying the polycrystalline silicon from above is provided between the first member and the second member, A first sensor provided above the first member and the second member, the first sensor detecting the distance between the polycrystalline silicon sandwiched between the first member and the second member and the first sensor, The polycrystalline silicon crushing apparatus according to claim 1, further comprising a control unit that controls the drive of the transport unit based on the distance detection result by the first sensor.

3. The polycrystalline silicon crushing apparatus according to claim 1, further comprising a housing provided below the first member and the second member, which forms a space for the accumulation of the polycrystalline silicon crushed by the first member and the second member.

4. A conveying unit for conveying the polycrystalline silicon from above is provided between the first member and the second member, A second sensor provided inside the housing, which detects whether the polycrystalline silicon deposited inside the housing has reached a predetermined height from the bottom surface of the housing, The polycrystalline silicon crushing apparatus according to claim 3, further comprising a control unit that stops the drive of the transport unit when the second sensor detects that the polycrystalline silicon deposited inside the housing has reached a predetermined height.

5. The polycrystalline silicon crushing apparatus according to claim 1, characterized in that the shortest interval is the interval when the first member and the second member are in the closest proximity.

6. A feeding step of inserting polycrystalline silicon between a first member and a second member positioned opposite the first member, The process includes a driving step of driving at least one of the first member and the second member to crush the polycrystalline silicon introduced in the feeding step by sandwiching it between the first member and the second member, A method for crushing polycrystalline silicon, characterized in that, in the driving step, at least one of the first member and the second member is driven such that the shortest distance between the first member and the second member is 17 mm or more and 30 mm or less.

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