Method for breaking up silicon mass

Abstract

This invention relates to the field of polysilicon production technology, and more particularly to a method for crushing silicon material, comprising the following steps: mechanically pre-treating a U-shaped silicon rod according to its segment size; subjecting the U-shaped silicon rod to a heating-rapid cooling treatment to break it into multiple segments; placing the silicon material into a crushing device after a second heating-rapid cooling treatment; and activating a pneumatic pulse device to supply air to the crushing device to crush the silicon material into small blocks. By subjecting the U-shaped silicon rod to heating-rapid cooling, the internal thermal stress of the U-shaped silicon rod induces cracks. The mechanical treatment prior to the heating-rapid cooling operation creates annular grooves on the U-shaped silicon rod, which serve as the starting point for crack formation. This promotes the expansion of the cracks at the annular grooves during the heating-rapid cooling process, facilitating the breaking of the U-shaped silicon rod into multiple segments. The cracks on the silicon material also facilitate subsequent pneumatic pulse crushing. The non-contact crushing method using pneumatic pulses reduces polysilicon contamination and ensures product quality.

Description

Technical Field

[0001] This invention relates to the field of polysilicon production technology, and in particular to a method for crushing silicon material. Background Technology

[0002] With the continuous increase in new photovoltaic installations globally, the corresponding annual demand for polysilicon is also rising significantly. Currently, the modified Siemens process is widely used in the production of photovoltaic polysilicon raw materials, accounting for over 97% of the total polysilicon production in China. The modified Siemens process mainly involves five stages: purification and tail gas recovery, separation of other hydrides, silicon synthesis, and reduction technologies.

[0003] In the improved Siemens process for manufacturing polycrystalline silicon, polycrystalline silicon reacts in a furnace to produce U-shaped silicon rods. These rods are approximately 250 cm long, 130 ± 20 mm in diameter, and weigh 270 kg. The silicon rods removed from the furnace need to be crushed before they can be packaged into finished silicon materials.

[0004] Current crushing technologies include manual crushing, mechanical pneumatic hammer crushing, and thermal crushing. Manual crushing typically uses tungsten carbide or cemented carbide hammers for crushing operations. However, when operating in a manual crushing mode, polysilicon can be contaminated, resulting in a large workload and low crushing efficiency. Summary of the Invention

[0005] This invention provides a method for crushing silicon material, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for crushing silicon material includes the following steps:

[0008] The U-shaped silicon rods are mechanically pre-treated according to their segment dimensions;

[0009] The U-shaped silicon rod is subjected to a heating-rapid cooling process, which breaks it into multiple segments of silicon material.

[0010] The silicon material is subjected to a second heating-rapid cooling treatment before being placed into a crushing device;

[0011] The pneumatic pulse equipment is activated to supply air to the crushing device, which crushes the silicon material into small blocks.

[0012] Furthermore, the U-shaped silicon rod is marked along its length according to the segment size, and then the marked positions on the U-shaped silicon rod are subjected to slight mechanical processing.

[0013] A slight mechanical treatment is performed by using a scriber to etch along the circumferential direction at the marked positions on the surface of the U-shaped silicon rod, forming multiple annular grooves along the length of the U-shaped silicon rod.

[0014] Furthermore, the U-shaped silicon rod and silicon material are heated in the first heating furnace and the second heating furnace respectively;

[0015] The heating temperature of the first heating furnace is controlled at 500-850℃, the heating temperature of the second heating furnace is controlled at 1000-1350℃, and the heating time of the material in the first and second heating furnaces is controlled at 10-20 minutes.

[0016] Furthermore, after heating and quenching the U-shaped silicon rod, the U-shaped silicon rod is repeatedly subjected to external force impacts at the end away from the annular groove, causing the U-shaped silicon rod to break into multiple segments of silicon material at the annular groove.

[0017] Furthermore, during the heating-quenching process of the U-shaped silicon rod and silicon material, the quenching operation is carried out by water cooling or liquid nitrogen cooling; the water cooling operation is carried out at room temperature, and the cooling water is circulated by a circulating pump.

[0018] Furthermore, after the silicon material is placed into the hopper of the crushing device, the hopper is sealed by the lifting mechanism and fixed by the first bolt. Then, the pneumatic pulse device is activated to blow high-pressure clean gas into the hopper, forming a pneumatic pulse to crush the silicon material.

[0019] Furthermore, during the placement of the silicon material, the silicon rods are laid side by side along the direction of the air inlet of the material tank and stacked layer by layer in the vertical direction.

[0020] Furthermore, the sealing cover includes a fixing plate and a cylindrical body disposed thereon. The cylindrical body abuts against the opening end of the material tank through a limiting ring disposed on its outer ring. The fixing plate is connected to the lifting mechanism.

[0021] The material tank is fixedly connected to the operating platform via a flange located at its open end. The cylinder extends into the material tank and forms a sealed cavity with the material tank cavity. The fixing plate is fixedly connected to the flange via the first bolt.

[0022] Furthermore, the lifting mechanism includes a support column and a motor, a lead screw, and a connecting seat mounted thereon. The support column is vertically mounted on the operating platform and is positioned opposite each other on both sides of the material tank. The connecting seat is screwed to the lead screw and slidably connected to the support column.

[0023] The lifting mechanism is fixedly connected to the fixed plate by an upper retaining ring and a lower retaining ring arranged opposite to each other. The upper retaining ring and the lower retaining ring abut against the two sides of the fixed plate respectively and are fixedly connected by a second bolt. The lower retaining ring is sleeved on the outer ring of the cylinder. The upper retaining ring and the lower retaining ring are both connected to the connecting seats on both sides.

[0024] Furthermore, a first sealing ring is provided on the side of the limiting ring facing the material tank, a second sealing ring is provided on the outer ring of the cylinder on the side of the limiting ring away from the fixing plate, and a third sealing ring is provided on the inner wall of the material tank near its opening end.

[0025] The beneficial effects of this invention are as follows:

[0026] In this invention, by heating and quenching the U-shaped silicon rod, the thermal stress inside the U-shaped silicon rod is used to create cracks. Before the heating and quenching operation, mechanical treatment is performed to form annular grooves on the U-shaped silicon rod, which can serve as the starting point for crack formation. This promotes the expansion of the gap at the annular grooves during the heating and quenching process, making it easier to break the U-shaped silicon rod into multiple segments of silicon material. The cracks on the silicon material are beneficial for the crushing device to further crush the silicon material into small blocks by means of air pressure pulse crushing.

[0027] In the crushing process of U-shaped silicon rods, mechanical pretreatment using a metal scriber is simple and does not introduce impurities. The initial heating-rapid cooling process induces intergranular stress and cracks in the U-shaped silicon rods, facilitating the segmentation of the U-shaped silicon rods into multiple silicon segments. The secondary heating-rapid cooling process further increases the internal stress of the silicon material, deepening and expanding the cracks, which is more conducive to subsequent pneumatic pulse crushing of the silicon material. The crushing process is highly automated, and the non-contact crushing method using pneumatic pulses reduces polysilicon contamination and ensures product quality. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the silicon material crushing method in this invention;

[0030] Figure 2 This is a schematic diagram of the crushing device in this invention;

[0031] Figure 3 This is a schematic diagram of the lifting mechanism in this invention;

[0032] Figure 4 This is a schematic diagram of the structure of the material tank and the sealing cap in this invention.

[0033] Reference numerals in the attached drawings: 1. Crushing device; 11. Lifting mechanism; 111. Support column; 112. Motor; 113. Lead screw; 114. Connecting seat; 115. Upper retaining ring; 116. Lower retaining ring; 117. Second bolt; 12. Sealing cover; 121. Fixing plate; 122. Cylinder; 123. Limiting ring; 124. First bolt; 125. First sealing ring; 126. Second sealing ring; 13. Material tank; 131. Flange; 132. Third sealing ring; 133. Air inlet; 2. Operating platform; 3. Pneumatic pulse device. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0035] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] like Figure 1 The method for crushing silicon material shown includes the following steps:

[0038] The U-shaped silicon rod is mechanically pre-treated according to the segment size; the U-shaped silicon rod is heated and rapidly cooled to break it into multiple silicon material segments; the silicon material is then heated and rapidly cooled again and placed into the crushing device 1; the pneumatic pulse device 3 is started to supply air to the crushing device 1 to crush the silicon material into small blocks.

[0039] Furthermore, the U-shaped silicon rod is marked along its length according to the segment size, and then the marked positions on the U-shaped silicon rod are slightly mechanically processed. The slight mechanical processing is achieved by using a scriber to slide along the circumferential direction at the marked positions on the surface of the U-shaped silicon rod, forming multiple annular grooves along the length of the U-shaped silicon rod.

[0040] In this invention, by heating and quenching the U-shaped silicon rod, the thermal stress inside the U-shaped silicon rod is used to cause cracks. Before the heating and quenching operation, mechanical treatment is performed to form annular grooves on the U-shaped silicon rod, which can serve as the starting point for crack formation. This promotes the expansion of the gap at the annular grooves during the heating and quenching process, making it easier to break the U-shaped silicon rod into multiple segments of silicon material. The cracks on the silicon material are beneficial for the crushing device 1 to further crush the silicon material into small blocks by means of air pressure pulse crushing.

[0041] In the crushing process of U-shaped silicon rods, mechanical pretreatment using a metal scriber is simple and does not introduce impurities. The initial heating-rapid cooling process induces intergranular stress and cracks in the U-shaped silicon rods, facilitating the segmentation of the U-shaped silicon rods into multiple silicon segments. The secondary heating-rapid cooling process further increases the internal stress of the silicon material, deepening and expanding the cracks, which is more conducive to subsequent pneumatic pulse crushing of the silicon material. The crushing process is highly automated, and the non-contact crushing method using pneumatic pulses reduces polysilicon contamination and ensures product quality.

[0042] In this embodiment, the U-shaped silicon rod and silicon material are heated by a first heating furnace and a second heating furnace, respectively. The heating temperature of the first heating furnace is controlled at 500-850℃, the heating temperature of the second heating furnace is controlled at 1000-1350℃, and the heating time of the material by the first heating furnace and the second heating furnace is controlled at 10-20 minutes.

[0043] The U-shaped silicon rod is heated evenly by the first heating furnace, which reduces the internal temperature gradient and makes it easier for cracks to form along the annular groove of the U-shaped silicon rod and extend inward during the quenching operation. This makes it easier for the U-shaped silicon rod to break at the annular groove position after the initial heating-quenching treatment.

[0044] The second heating furnace has a higher temperature than the first heating furnace. The multi-segment silicon material has a larger surface area than the entire U-shaped silicon rod. After dividing a U-shaped silicon rod into multiple segments, it undergoes a second heating and rapid cooling process in the second heating furnace to increase the intergranular stress of the silicon material. This not only further deepens the cracks generated by the initial heating and rapid cooling process, but also expands the crack density on the silicon material.

[0045] In the above embodiment, after the U-shaped silicon rod is subjected to heating-rapid cooling treatment, the U-shaped silicon rod is repeatedly subjected to external force impact at the end of the U-shaped silicon rod away from the annular groove, so that the U-shaped silicon rod is broken at the annular groove to form multiple segments of silicon material.

[0046] In the specific implementation process, an annular groove is set in the middle of the bent part of the U-shaped silicon rod to reduce the curvature of the silicon material formed in the bent part of the U-shaped silicon rod; during the process of applying impact force to the U-shaped silicon rod, the high pressure gas generated by the pneumatic equipment can quickly impact the end of the silicon rod, and generate a high impact force through a faster impact speed, avoiding direct contact with the silicon rod and reducing the possibility of silicon material contamination.

[0047] In the above embodiments, during the heating-quenching process of the U-shaped silicon rod and silicon material, the quenching operation is carried out by water cooling or liquid nitrogen cooling; the water cooling operation is carried out at room temperature, and the cooling water is circulated by a circulating pump.

[0048] Rapid cooling with liquid nitrogen can quickly cool silicon to extremely low temperatures. The high cooling rate can generate a large temperature gradient and thermal stress inside the silicon, but it requires specialized storage and transportation equipment, and safety issues must be considered during operation.

[0049] Water cooling is a common and effective cooling method compared to liquid nitrogen. It uses water as the cooling medium, which is less expensive. At the same time, using a circulating pump to circulate the cooling water can improve the cooling rate of silicon.

[0050] In this invention, after the silicon material is placed into the material tank 13 of the crushing device 1, the sealing cover 12 is driven by the lifting mechanism 11 to seal the material tank 13 and is fixed by the first bolt 124. Then, the pneumatic pulse device 3 is activated to blow high-pressure clean gas into the material tank 13, forming a pneumatic pulse to crush the silicon material. During the placement of the silicon material, the silicon rods are laid side by side along the direction of the air inlet 133 of the material tank 13 and stacked layer by layer in the vertical direction.

[0051] like Figures 2 to 4 The crushing device 1 shown has a sealing cover 12 including a fixing plate 121 and a cylinder 122 disposed thereon. The cylinder 122 abuts against the opening end of the material tank 13 through a limiting ring 123 disposed on its outer ring. The fixing plate 121 is connected to the lifting mechanism 11. The material tank 13 is fixedly connected to the operating platform 2 through a flange 131 disposed on its opening end. The cylinder 122 extends into the material tank 13 and cooperates with the cavity of the material tank 13 to form a sealed cavity. The fixing plate 121 is fixedly connected to the flange 131 through a first bolt 124.

[0052] After the silicon material is placed into the material tank 13, the lifting mechanism 11 drives the sealing cover 12 to extend its cylinder 122 into the material tank 13 and slide it into its inner wall until the limiting ring 123 on the outer wall of the cylinder 122 abuts against the top of the material tank 13. Then, the sealing cover 12 is fixedly connected to the flange 131 by the first bolt 124. After the pneumatic pulse crushing operation is completed, the fixed connection of the first bolt 124 is released, and the lifting mechanism 11 drives the sealing cover 12 to move upward and separate it from the material tank 13.

[0053] See further Figure 2As shown, the lifting mechanism 11 includes a support column 111 and a motor 112, a lead screw 113, and a connecting seat 114 mounted thereon. The support column 111 is vertically mounted on the operating platform 2 and is positioned opposite each other on both sides of the material tank 13. The connecting seat 114 is screwed to the lead screw 113 and slidably connected to the support column 111. The lifting mechanism 11 is fixedly connected to the fixing plate 121 via an upper retaining ring 115 and a lower retaining ring 116 positioned opposite each other. The upper retaining ring 115 and the lower retaining ring 116 abut against both sides of the fixing plate 121 and are fixedly connected by a second bolt 117. The lower retaining ring 116 is sleeved on the outer ring of the cylinder 122, and both the upper retaining ring 115 and the lower retaining ring 116 are connected to the connecting seats 114 on both sides. The upper retaining ring 115 and the lower retaining ring 116, together with the second bolt 117, tightly hold and fix the fixing plate 121 of the sealing cover 12, thereby achieving a fixed connection between the lifting mechanism 11 and the sealing cover 12.

[0054] See further Figure 4 As shown, a first sealing ring 125 is provided on the side of the limiting ring 123 facing the material tank 13, a second sealing ring 126 is provided on the outer ring of the cylinder 122 on the side of the limiting ring 123 away from the fixing plate 121, and a third sealing ring 132 is provided on the inner wall of the material tank 13 near its opening end.

[0055] The first sealing ring 125 achieves a planar seal between the limiting ring 123 and the end face of the material tank 13, and the second sealing ring 126 and the third sealing ring 132 achieve a seal between the sealing cover 12 cylinder 122 and the inner wall of the material tank 13, ensuring the sealing effect of the cylinder 122 and the cavity of the material tank 13 forming a sealed cavity.

[0056] Using pneumatic pulse crushing avoids direct contact with the silicon material, thus reducing contamination. The pneumatic pulse not only generates instantaneous impact force, creating a high-pressure environment within the sealed cavity that further deepens cracks, but also generates more cracks, effectively breaking the silicon material into smaller pieces. The pneumatic pulse equipment 3 is equipped with pressure sensors and safety valves to ensure automatic pressure relief under abnormally high pressure conditions, guaranteeing operational safety.

[0057] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for crushing silicon material, characterized in that, Includes the following steps: The U-shaped silicon rods are mechanically pre-treated according to their segment dimensions; The U-shaped silicon rod is subjected to a heating-rapid cooling process, which breaks it into multiple segments of silicon material. The silicon material is subjected to a second heating-rapid cooling treatment before being placed into a crushing device; The pneumatic pulse equipment is activated to supply air to the crushing device, which crushes the silicon material into small blocks. Mark the U-shaped silicon rod along its length according to the segment dimensions, and then perform slight mechanical processing on the marked positions of the U-shaped silicon rod; Slight mechanical processing involves using a scriber to etch along the circumferential direction at marked positions on the surface of the U-shaped silicon rod, forming multiple annular grooves along the length of the U-shaped silicon rod. The U-shaped silicon rod and silicon material are heated in the first heating furnace and the second heating furnace respectively; The heating temperature of the first heating furnace is controlled at 500-850℃, the heating temperature of the second heating furnace is controlled at 1000-1350℃, and the heating time of the material in the first and second heating furnaces is controlled at 10-20 minutes. After the U-shaped silicon rod is heated and then rapidly cooled, the end of the U-shaped silicon rod away from the annular groove is subjected to multiple external impacts, causing the U-shaped silicon rod to break into multiple segments of silicon material at the annular groove.

2. The silicon material crushing method according to claim 1, characterized in that, During the heating-quenching process of U-shaped silicon rods and silicon materials, the quenching operation is carried out by water cooling or liquid nitrogen cooling; the water cooling operation is carried out at room temperature, and the cooling water is circulated by a circulating pump.

3. The silicon material crushing method according to claim 1, characterized in that, After the silicon material is placed into the hopper of the crushing device, the hopper is sealed by the lifting mechanism and fixed by the first bolt. Then, the pneumatic pulse device is started to blow high-pressure clean gas into the hopper to form a pneumatic pulse to crush the silicon material.

4. The silicon material crushing method according to claim 3, characterized in that, During the placement of silicon material, silicon rods are laid side by side along the air inlet of the material tank and stacked layer by layer in the vertical direction.

5. The silicon material crushing method according to claim 3, characterized in that, The sealing cover includes a fixing plate and a cylindrical body disposed thereon. The cylindrical body abuts against the opening end of the material tank through a limiting ring disposed on its outer ring. The fixing plate is connected to the lifting mechanism. The material tank is fixedly connected to the operating platform via a flange located at its open end. The cylinder extends into the material tank and forms a sealed cavity with the material tank cavity. The fixing plate is fixedly connected to the flange via the first bolt.

6. The silicon material crushing method according to claim 5, characterized in that, The lifting mechanism includes a support column and a motor, a lead screw, and a connecting seat mounted thereon. The support column is vertically mounted on the operating platform and is positioned opposite each other on both sides of the material tank. The connecting seat is screwed to the lead screw and slidably connected to the support column. The lifting mechanism is fixedly connected to the fixed plate by an upper retaining ring and a lower retaining ring arranged opposite to each other. The upper retaining ring and the lower retaining ring abut against the two sides of the fixed plate respectively and are fixedly connected by a second bolt. The lower retaining ring is sleeved on the outer ring of the cylinder. The upper retaining ring and the lower retaining ring are both connected to the connecting seats on both sides.

7. The silicon material crushing method according to claim 5, characterized in that, A first sealing ring is provided on the side of the limiting ring facing the material tank, a second sealing ring is provided on the outer ring of the cylinder on the side of the limiting ring away from the fixing plate, and a third sealing ring is provided on the inner wall of the material tank near its opening end.

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