JP2015202442A - Crusher of polycrystalline silicon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To crush polycrystalline silicon with one crusher by an optimum crushing rate without adjusting gaps of crushing rolls while suppressing a loss rate.SOLUTION: The outer peripheral face of a crushing roll 2 is provided with a plurality of crushing teeth 10 by radially outward projection. Gaps between circumcircles 25 that pass the tips of the plurality of crushing teeth 10 of each crushing roll 2 are so arranged as to be wider on the side of the tip 5 of the crushing roll 2 than on the side of the base end 4. The upper position of the opposite parts of these crushing rolls 2 is provided with a pair of feed conveyors 3 to supply polycrystalline silicon through the crushing rolls 2. These feed conveyors 3 are arranged by inclination so that the transportation face for polycrystalline silicon may be gradient in the crosswise direction downward inside in opposition direction and arranged so as to gradually enlarge mutual gaps in horizontal directions of inside edges in opposition directions from the side of the base end 20 of the feed conveyors 3 toward the tip 21.

Description

  The present invention relates to a polycrystalline silicon crushing apparatus for crushing polycrystalline silicon used as a raw material for semiconductor silicon into a lump.

A silicon wafer used for a semiconductor chip is manufactured from, for example, single crystal silicon manufactured by the Czochralski (CZ) method. For the production of single crystal silicon by the CZ method, for example, a material obtained by crushing polycrystalline silicon formed into a rod shape by the Siemens method into a lump shape is used.
As shown in FIG. 7, the polycrystalline silicon is crushed into a polycrystalline silicon rod R having a mass S of several mm to several cm, and the rod R is appropriately sized by thermal shock or the like. A method of directly crushing with a hammer after crushing is generally used, but the burden on the operator is large, and it is inefficient to obtain a lump of a desired size from rod-shaped polycrystalline silicon.

  In order to avoid this burden, a technique is known in which a massive silicon crushed material crushed to an appropriate size is crushed to a desired size by a crusher. In this crushing, it is important to reduce the generation of loss (fine powder). In order to reduce the occurrence of loss, in the crusher with crushing teeth provided on the roll, it is necessary for the thickness of the bulk polycrystalline silicon (hereinafter referred to as “chunk”) charged into the crusher. It is necessary not to push the crushing teeth above, that is, to crush while giving an appropriate crushing ratio for each size of polycrystalline silicon.

  As a technique of this type, for example, in Patent Document 1, a method of obtaining a finely pulverized silicon product having a desired size by supplying a lump of crushed silicon to a pulverizer provided with a pair of rolls a plurality of times and repeating crushing. Has been proposed. In this case, the silicon crushed material is pulverized by a pulverizer at a predetermined pulverization ratio (crushing ratio), and the silicon pulverized product obtained after pulverization is smaller than the maximum side length of the silicon pulverized product of a desired size, or Classification is made into those having equal side lengths and those having side lengths greater than the desired size. Furthermore, while narrowing the gap between the rolls in multiple stages, a pulverized product having a longer side length than the desired silicon fine pulverized product is supplied again to the same pulverizer and pulverized, and the silicon fine pulverized product is reduced to the target size. Crush many times.

Japanese Patent No. 4351666

However, the chunks thrown into the crusher are indefinite, and in the case of Patent Document 1, in order to obtain a crushing ratio according to the chunks having various thicknesses, the gaps of the rolls are individually adjusted every time crushing is performed. It took time and effort to do that. Moreover, it is difficult to individually adjust the rolls, and as a result, the loss tends to increase.
Also, instead of the method of repeating crushing multiple times while adjusting the roll interval with one crusher, prepare crushers with different crushing ratios and crush using these crushers in sequence. However, it is conceivable to increase the size of the entire apparatus and increase the cost.

  The present invention has been made in view of such circumstances, and it is possible to crush polycrystalline silicon with an optimum crushing ratio and a loss rate without adjusting the crushing roll gap with a single crushing device. An object of the present invention is to provide an apparatus for crushing polycrystalline silicon.

  The present invention relates to a polycrystalline silicon crushing apparatus that crushes a lump of polycrystalline silicon sandwiched between a pair of crushing rolls that rotate reversely to each other, and a plurality of crushing teeth are radially outward on the outer peripheral surface of the crushing roll. The distance between the circumscribed circles passing through the tips of a plurality of crushing teeth of each crushing roll is arranged so that the front end side is wider than the base end side of the crushing roll, and the opposing portions of these crushing rolls Are provided with a pair of feed conveyors for supplying polycrystalline silicon between the crushing rolls, and these feed conveyors are arranged so that the width direction of the polycrystalline silicon transport surface of each feed conveyor is in the opposite direction inside. Inclined so as to form a downward slope, and gradually increases the horizontal distance between the inner edges in the opposite direction from the base end side to the front end side of the feed conveyor. Characterized in that it is arranged.

When lump-like polycrystalline silicon is put between a pair of feed conveyors, the polycrystalline silicon is sent from the proximal end side to the distal end side of the feed conveyor as the transport surface (feed belt) of the feed conveyor moves. And since this feed conveyor is arranged so as to gradually widen the mutual distance in the horizontal direction of the inner edge in the opposite direction as it goes from the base end side to the tip end side, the base end side compares according to the interval. The smaller polycrystalline silicon, the progressively larger polycrystalline silicon falls from between the two feed conveyors to the lower crushing roll as it goes to the front end side. Since this crushing roll is also arranged so that the front end side is wider than the base end side between the circumscribed circles passing through the tips of the plurality of crushing teeth, it can be crushed at intervals according to the thickness of the polycrystalline silicon, It is possible to crush relatively small polycrystalline silicon on the base end side and gradually larger polycrystalline silicon toward the front end side. Therefore, it becomes possible to crush at a predetermined crushing ratio corresponding to the size of the polycrystalline silicon without adjusting the interval between crushing rolls.
Moreover, since the moving speed of the polycrystalline silicon can be adjusted by adjusting the feeding speed of the feeding conveyor, the throughput of the polycrystalline silicon crushing can be improved by increasing the feeding speed of the feeding conveyor. .
Furthermore, polycrystalline silicon having a desired size can be obtained by classifying the polycrystalline silicon after crushing and repeatedly crushing polycrystalline silicon larger than a predetermined size with the same crushing apparatus.
In addition, it is possible to change the crushing ratio as appropriate by changing the horizontal angle between the feed conveyors. For example, the crushing ratio is increased by widening the mutual interval on the front end side or reduced to reduce the crushing ratio. It is possible.

In the polycrystalline silicon crushing apparatus according to the present invention, the pair of feed conveyors may be set to have different feed speeds.
When the polycrystalline silicon supplied on the feed conveyor is stacked between the opposing portions of the feed conveyor, for example, when a small polycrystalline silicon is placed on a large polycrystalline silicon (this is called a bridge phenomenon), The small polycrystalline silicon is transported to a position away from a predetermined position together with the large polycrystalline silicon and dropped, and may pass between the crushing rolls without being crushed. In this case, the number of times the polycrystalline silicon is crushed is increased, resulting in an increase in loss generation.
In the polycrystalline silicon crushing apparatus of the present invention, by setting the feed speed of the pair of feed conveyors to different speeds, it is possible to prevent the formation of a bridge of polycrystalline silicon on the feed conveyor, and the bridge is formed. Even in this case, the polycrystalline silicon can be rolled by one feed conveyor set at a high feed speed, and the bridge can be broken at an early stage on the base end side of the feed conveyor, so that the accuracy of crushing ratio control is not lowered. The processing amount of the crushing device can be increased.

  In the polycrystalline silicon crushing apparatus according to the present invention, the mutual interval between the feed conveyors and the interval between circumscribed circles passing through the tips of the crushing teeth of the crushing roll are the same between the feed conveyors in the same section along the vertical direction. The ratio of the interval between the circumscribed circles relative to the interval may be set to substantially the same ratio in the length direction.

  The distance between the feed conveyors limits the thickness of the polycrystalline silicon falling from between them, and the distance between the circumscribed circles passing through the tips of the crushing teeth of the crushing roll determines the size of the polycrystalline silicon after crushing. Restrict. Therefore, the ratio of the distance between the circumscribed circles to the distance between the feed conveyors in the same cross section along the vertical direction is the ratio of the size of polycrystalline silicon after crushing to the size of polycrystalline silicon to be supplied, that is, the crushing ratio. As a result, the ratio is set to substantially the same ratio in the length direction, so that it can be crushed at almost the same crushing ratio regardless of the size of the supplied polycrystalline silicon.

  In the polycrystalline silicon crushing device of the present invention, the crushing teeth may be arranged at a narrow pitch on the side where the interval between the circumscribed circles is narrow, and at a wide pitch on the side where the interval between the circumscribed circles is wide.

  In this crushing device, polycrystalline silicon can be continuously hit by crushing teeth while rotating crushing rolls to efficiently crush the crushing teeth. At this time, each crushing tooth has a circumscribed circle passing through the tips of the crushing teeth. Narrow pitches are arranged on the narrow side, and wide pitches on the side where the circumscribed circles are wide, so it can be crushed with the optimal crushing tooth arrangement according to the size of the polycrystalline silicon. It is also possible to prevent fine powder from being crushed by the crushing teeth.

In the polycrystalline silicon crushing apparatus of the present invention, a pair of classification rollers for classifying the polycrystalline silicon dropped from between the crushing rolls is provided at a position below the opposing portion of the crushing rolls, and these classification rollers are installed in parallel. The horizontal interval may be set to a product size to be classified, and may be arranged so as to be inclined downward toward the base end side or the tip end side of the crushing roll.
By setting the interval between the classification rollers to the desired product size, the polycrystalline silicon after crushing can be classified, and if the crushed polycrystalline silicon is within the product size, between the classification rollers If it exceeds the desired size, it falls from the base end or the tip according to the gradient of the classification roller.

In this case, it is preferable that a feed-back mechanism is provided at the lower end of the descending gradient of the classifying roller to supply again the polycrystalline silicon that has not dropped from between the classifying rollers to the feed conveyor.
Polycrystalline silicon outside the product size exceeding the desired size is again fed to the feed conveyor and crushed, and this is repeated as necessary to obtain a desired size.

  Moreover, the polycrystalline silicon crushing apparatus of this invention WHEREIN: The said conveyance surface of the said feed conveyor is good to be formed with the polyolefin resin from a viewpoint of preventing mixing of the impurity to the polycrystalline silicon to crush.

  According to the polycrystalline silicon crushing apparatus of the present invention, it is possible to crush polycrystalline silicon with an optimal crushing ratio and a loss rate without adjusting the gap between crushing rolls with a single crushing apparatus. As a result, it is possible to obtain a high-quality polycrystalline silicon fragment that is equivalent to the case of splitting by hand.

It is a perspective view which shows one Embodiment of the crushing apparatus of the polycrystalline silicon which concerns on this invention. It is a top view of FIG. It is a side view of FIG. It is sectional drawing which shows arrangement | positioning with the crushing roll and feed conveyor in a specific vertical cross section. It is the perspective view which abbreviate | omitted one part which shows the surface state of a crushing roll. It is a perspective view which shows a crushing tooth unit. It is a schematic diagram which shows what crushed the rod of polycrystalline silicon into a lump.

Hereinafter, embodiments of a polycrystalline silicon crushing apparatus according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the polycrystalline silicon crushing apparatus 100 according to the present embodiment includes a pair of crushing rolls 2, 2 and a pair of feed conveyors 3, 3. Bulked polycrystalline silicon is sandwiched and crushed. Further, the polycrystalline silicon crushed between the crushing rolls 2 and 2 can be further classified by the pair of classification rolls 31 and 31 so that those exceeding a predetermined dimension can be returned to the conveyors 3 and 3 again and crushed. It has become.

  The pair of crushing rolls 2, 2 rotate in the direction of the arrow shown in FIG. 4, and a plurality of crushing teeth 10 are provided on the outer peripheral surface so as to protrude radially outward. The interval between the circumscribed circles 25 passing through the distal ends of the plurality of crushing teeth 10 is arranged so that the distal end 5 side is wider than the proximal end 4 side, and the interval between the circumscribed circles 25 at the proximal end 4 is narrow, and the distal end 5 side The distance between the circumscribed circles 25 is wider than the distance between the base ends 4.

  Further, each crushing tooth 10 has a narrower pitch and a distance between the circumscribed circles 25 as the distance between the circumscribed circles 25 passing through the distal ends of the crushing teeth 10 of the pair of crushing rolls 2 and 2 becomes narrower (base end side). It arrange | positions with a wide pitch as the space | interval becomes a wide side (front end side). In this embodiment, the space | interval of the circumscribed circle 25 which passes along the front-end | tip of the some crushing tooth 10 becomes large in order shown to AF in FIG.2 and FIG.3, and the pitch of the crushing tooth 10 is also wide in order of A-F. It has become.

  In this case, as shown in FIG. 5, the outer peripheral surface of each crushing roll 2, 2 is not a uniform cylindrical surface, but a polyhedral shape formed by connecting long flat surfaces 11 along the axial direction in the circumferential direction. Screw holes 13 are provided at both ends of each flat surface 11, and the crushing tooth units 12 are fixed to the flat surfaces 11 one by one with screws 14.

  As shown in FIG. 6, the crushing tooth unit 12 includes a strip-shaped fixed cover 15 that comes into contact with the flat surface 11 of the crushing roll 2, and a plurality of crushing teeth 10 attached to the fixed cover 15. . The crushing teeth 10 are provided with a cemented carbide or a silicon material, and the tip portion 16 is formed in a spherical shape, for example, and the side surface portion 17 is formed in a cylindrical surface shape.

  The fixed cover 15 is formed in a strip shape having the same width and length as the flat surface 11 of the crushing roll 2, and a plurality of fixing holes (not shown) for attaching crushing teeth are formed in a penetrating state in the longitudinal direction. The crushing teeth 10 are fixed to the fixed cover 15 in a state of being prevented from rotating by an appropriate means such as fitting into the fixed hole.

  Each crushing tooth unit 12 is attached in a state where crushing teeth 10 are arranged in a staggered manner so that crushing teeth 10 of adjacent crushing tooth units 12 do not line up continuously in the circumferential direction of crushing roll 2, for example. On the other hand, between the two crushing rolls 2, the front end portions 16 of the crushing teeth 10 of the two crushing rolls 2 are arranged so as to face each other at the facing portion.

The pair of feed conveyors 3 is formed by, for example, a belt conveyor in which a rotating belt rotates, and polycrystalline silicon is placed between a pair of rotating belts that move from the base end 4 side to the tip end 5 side of the crushing roll 2. Silicon is fed between the crushing rolls 2 while being sent in the lengthwise direction of the rotating belt, and is provided above the opposing portion of the crushing rolls 2 and 2. These feed conveyors 3 are disposed so that the width direction of the polycrystalline silicon transfer surface of each feed conveyor 3 is inclined downward inward in the opposite direction, and the distal end 21 from the base end 20 side of the feed conveyor 3. It arrange | positions so that the mutual space | interval of the horizontal direction of the inner edge of an opposing direction may be gradually expanded as it goes to the side.
In addition, the feed conveyor 3 has a mounting surface made of a high-hardness resin such as polyolefin resin (for example, polyethylene, polypropylene) or silicon-coated from the viewpoint of preventing impurities from being mixed into the polycrystalline silicon. Is used. And a pair of feed conveyor 3 is set to the speed from which the feed speed of each feed conveyor 3 differs.
In addition, in FIG. 1, although the feed conveyor 3 is drawn small so that a structure can be understood easily, the large-sized feed conveyor 3 is used suitably from what is shown in FIG. 1 from a viewpoint of operativity.

  In this way, the polycrystalline silicon supplied between the rotary belts of the feed conveyors 3 can be sent in the direction of the tip 21 as the rotary belts of the feed conveyors 3 move. At that time, as the feed conveyor 3 moves from the proximal end 20 side toward the distal end 21 side, the mutual distance in the horizontal direction of the inner edges in the opposing direction gradually widens by a predetermined angle, so that the mutual distance decreases toward the proximal end 20 side. While the supplied crushed pieces are sent to the tip 21 side by the two-feed conveyors 3, 3, those smaller than the mutual interval are sequentially dropped onto the crushing roll 2 from between the feed conveyors 3. . Therefore, a small crushed piece falls on the base end 20 side of the feed conveyor 3 and a large crushed piece falls on the tip 21 side.

  Further, the mutual interval between the feed conveyors 3 and the mutual interval between the crushing rolls 2 (intervals between circumscribed circles 25 passing through the tips of the plurality of crushing teeth 10) are the same in the same vertical cross-sectional position orthogonal to the feed direction. As shown in FIG. 2, the mutual interval G1 of the feed conveyor 3 is set to be wider than the mutual interval G2 of the crushing roll 2, and the mutual interval of the feed conveyor 3 with respect to the mutual interval of the crushing roll 2 in the vertical cross section is set. The ratio (G1 / G2) is set to substantially the same ratio over the length direction. This ratio, that is, (feed conveyor mutual interval) / (crush roll mutual interval) is (size of input polycrystalline silicon to be crushed) / (target crushed piece size). is there.

The classifying rollers 31 and 31 are provided below the opposing portions of the crushing rolls 2 and 2, and these classifying rollers 31 and 31 are arranged in parallel, and the horizontal distance between them is constant over the entire length. Inclined downward from the proximal side toward the distal side. The horizontal distance between the classification rollers 31 and 31 is set to the product size to be classified.
In addition, the rotation direction of the classification rollers 31 and 31 is a direction in which the outer peripheral surfaces of the rollers 31 and 31 move from the bottom to the top between the facing portions. Further, on both sides of the classification rollers 31, 31 are provided shooters 32 for guiding polycrystalline silicon falling from between the crushing rolls 2, 2 between the classification rollers 31, 31.
Further, a container 33 for collecting polycrystalline silicon falling from between the classification rollers 31 and 31 is installed below the opposing portions of the classification rollers 31 and 31, and at the tips of the classification rollers 31 and 31, A feed back mechanism 34 for supplying the polycrystalline silicon that has not dropped from between the classification rollers 31 and 31 to the base end portion of the feed conveyor 3 is connected. The feed back mechanism 34 can be configured by combining a conveyor, a shooter, and the like.

  The crushing apparatus 100 is provided with a housing (not shown) for accommodating the crushing roll 2, the feed conveyor 3, the classification roller 31, and the like. This housing is made of polypropylene or the like from the viewpoint of preventing impurities from being mixed into the polycrystalline silicon. Or a metal housing with an inner surface coated with tetrafluoroethylene is used.

When crushing polycrystalline silicon crushing pieces using the crushing apparatus 100 configured as described above, a crushing piece of polycrystalline silicon having an appropriate size coarsely crushed in advance with both crushing rolls 2 and 2 rotated. When thrown into the base end 20 side of the feed conveyor 3, the crushed pieces fall on the crushing roll 2 from between the feed conveyors 3 at a position smaller than the mutual interval between the feed conveyors 3, 3 as described above.
At this time, the moving speed of the polycrystalline silicon can be adjusted by adjusting the feed speed of the pair of feed conveyors 3. That is, by increasing the feed speed of the feed conveyor 3, the moving speed of the polycrystalline silicon can be increased, and the processing amount of crushing can be improved.
Further, since the pair of feed conveyors 3 are set at different feed rates, the polycrystalline silicon is rolled by one feed conveyor 3 set at a fast feed rate, and the base end of the feed conveyor 3 is set. You can break the bridge early on the side. Therefore, the processing amount of crushing can be increased without reducing the accuracy of crushing ratio control.

Then, the polycrystalline silicon dropped between the crushing rolls 2 and 2 is crushed by the crushing teeth 10 into small blocks. At this time, the mutual gap G2 between the pair of crushing rolls 2 and 2 and the mutual gap G1 between the pair of feed conveyors 3 and 3 are the ratio (G1 / G1) in the same vertical cross section orthogonal to the feed direction, as described above. Since G2) is set to substantially the same ratio over the length direction, it can be crushed at a substantially constant crushing ratio over the length direction. And small polycrystalline silicon is supplied between the crushing rolls 2 and 2 at the base end side of the double feed conveyor 3, and large polycrystalline silicon is supplied toward the front end side so as to match the size of the polycrystalline silicon. Further, the crushing roll 3 is also arranged with gradually increasing mutual distance from the base end side to the front end side, and therefore, it can be crushed at a substantially constant crushing ratio regardless of the size of the polycrystalline silicon to be charged.
As described above, the feed conveyor 3 is wider than the crushing roll 2 at the same vertical cross-sectional position, so that the crushing pieces dropped from between the feed conveyors 3 are crushing teeth 10 and 10 of the crushing roll 2. The crushed pieces can be reliably crushed by the crushing teeth 10.

The polycrystalline silicon crushed between the two crushing rolls 2 is guided between the classification rollers 31 and 31 below the crushing roll 2, and has a predetermined size set by the mutual interval between the classification rollers 31 and 31. Crystalline silicon falls from between the classification rollers 31 and 31 and is collected in the container 33, and polycrystalline silicon larger than a predetermined size falls from the tips of the classification rollers 31 and 31. The polycrystalline silicon dropped from between the classification rollers 31 and 31 is provided as a product, while the polycrystalline silicon dropped from the tip of the classification rollers 31 and 31 is returned to the feed conveyor 3 via the feed back mechanism 34 and again. The crushing process is repeated.
Thus, by repeating the crushing of only the polycrystalline silicon larger than the predetermined size while classifying the polycrystalline silicon crushed between the crushing rolls 2, the number of repetitions can be minimized and the loss can be reduced.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
In the above-described embodiment, the outer diameter of the crushing roll 2 is set to be the same over the entire length, and the distance between both axes is gradually increased toward the tip. If the arrangement becomes gradually larger according to the above, various configurations can be adopted without being limited to the above-described embodiment.
For example, the crushing roll is formed in a tapered shape and the axes are arranged in parallel with each other. The stepping roll is gradually reduced in diameter toward the tip, and the axes are arranged in parallel with each other. It is good also as a structure of these. Further, the outer peripheral surface of the crushing roll has a stepped shape or a tapered shape that gradually increases in diameter toward the tip, and is arranged so that the mutual distance in the horizontal direction gradually increases as the axis is directed toward the tip. By doing, it can arrange | position so that the front end side may become wider from the base end side about the space | interval of the circumscribed circle which passes along the front-end | tip of the some crushing tooth of each crushing roll.
In addition, the crushing ratio set by the mutual distance between the feed conveyors and the mutual distance between the crushing rolls is set to substantially the same ratio in the length direction. For example, the mutual distance between the crushing rolls is not changed. To increase the crushing ratio gradually toward the front end side, or to reduce the crushing ratio toward the front end side by decreasing the spacing between the front ends of the feed conveyor, so that polycrystalline silicon can be introduced from the front end side. Is possible.
Furthermore, in the said embodiment, although the inclination angle of the width direction of the feed conveyor 3 was provided as a fixed inclination angle, the inclination angle of a base end 20 side and the front-end | tip 21 side is set to a different angle, and an inclination angle is changed gradually. It is also possible.

Moreover, the feed conveyor 3 can also be set as the structure which made the silicon plate or the silicon | silicone stick stand upright on the mounting surface at intervals in the moving direction. In this case, since the silicon plate or the silicon rod also moves as the placement surface of the feed conveyor 3 moves, the polycrystalline silicon can be moved smoothly.
Regarding the crushing teeth, the method of fixing the crushing teeth to the crushing roll 2 using the fixed cover 15 has been shown. However, as a method of fixing the crushing teeth directly to the roll surface, a planting bolt is disposed on the roll surface, and crushing is performed on the planting bolt. Teeth may be fastened.
Moreover, although each crushing tooth unit 12 was attached in the state where the crushing teeth 10 were arranged in a staggered manner, the arrangement of crushing teeth is not limited to this. It is good also as a structure which arranges the crushing tooth 10 of the adjacent crushing tooth unit 12 continuously in the circumferential direction of the crushing roll 2. FIG.

DESCRIPTION OF SYMBOLS 100 Polycrystalline silicon crushing device 2 Crushing roll 3 Feeding conveyor 4 Crushing roll base 5 Crushing roll tip 10 Crushing tooth 11 Flat surface 12 Crushing tooth unit 13 Screw hole 14 Screw 15 Fixed cover 16 Tip part 17 Side part 20 Feeding Conveyor base 21 Feed conveyor tip 25 circumscribed circle 31 classification roller 32 shooter 33 container 34 feed back mechanism

Claims (7)

  A polycrystalline silicon crushing device for crushing by sandwiching massive polycrystalline silicon between a pair of crushing rolls rotating in reverse, and a plurality of crushing teeth project radially outward on the outer peripheral surface of the crushing roll. The distance between the circumscribed circles passing through the tips of the crushing teeth of each crushing roll is arranged so that the tip side is wider than the base end side of the crushing roll, A pair of feed conveyors for supplying polycrystalline silicon between the crushing rolls are provided, and these feed conveyors are inclined downward in the widthwise direction of the polycrystalline silicon transport surface of each feed conveyor in the opposite direction inside. Are arranged so as to be gradually inclined and the horizontal distance between the inner edges in the opposite direction is gradually increased from the base end side to the front end side of the feed conveyor. Apparatus for fracturing polycrystalline silicon, characterized in that is.   2. The polycrystalline silicon crushing apparatus according to claim 1, wherein the pair of feed conveyors is set to have different feed speeds.   The interval between the feed conveyors and the interval between the circumscribed circles passing through the tips of the crushing teeth of the crushing roll are the ratio of the interval between the circumscribed circles to the interval between the feed conveyors in the same cross section along the vertical direction. The polycrystalline silicon crushing apparatus according to claim 1, wherein the ratio is set to be the same in the length direction.   4. The crushing teeth are arranged at a narrow pitch on a side where the interval between the circumscribed circles is narrow, and at a wide pitch on a side where the interval between the circumscribed circles is wide. The polycrystalline silicon crushing apparatus described in 1.   A pair of classification rollers for classifying the polycrystalline silicon dropped from between the crushing rolls is provided at a position below the opposing part of the crushing rolls. These classification rollers are installed in parallel, and the horizontal interval should be classified. It is set to a product size, and it inclines and arrange | positions in a downward slope as it goes to either the base end side or the front end side of the said crushing roll, It is any one of Claim 1 to 4 characterized by the above-mentioned. The polycrystalline silicon crushing apparatus described in 1.   6. The polycrystalline silicon according to claim 5, wherein a feed-back mechanism is provided at the lower end of the descending slope of the classifying roller to supply again the polycrystalline silicon that has not fallen from between the classifying rollers to the feed conveyor. Crushing equipment.   The polycrystalline silicon crushing apparatus according to any one of claims 1 to 6, wherein the transport surface of the feed conveyor is made of a polyolefin-based resin.

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