Crushing device used after pretreatment of polycrystalline silicon bars

Abstract

The utility model relates to the technical field of polycrystalline silicon bar crushing, in particular to a crushing device used after pretreatment of polycrystalline silicon bars, and adopts the technical scheme that the crushing device comprises a first-stage crushing device and a first-stage screening device which are sequentially connected, and an oversize product discharge port of the first-stage screening device is connected with a second-stage crushing device; a screen underflow discharging opening of the primary screening device is connected with a secondary screening device, and a discharging opening of the secondary crushing device is connected to the secondary screening device; a cooling and conveying device is arranged between the first-stage crushing device and the first-stage screening device, and / or an oversize product discharge port of the second-stage screening device is connected with the cooling and conveying device. The multi-stage crushing and screening device is provided with multi-stage crushing and screening, and is combined with a cooling and conveying device to discharge moisture and reduce temperature, so that the multi-stage crushing and screening device is more suitable for continuous crushing production of polycrystalline silicon bars subjected to water quenching or thermal crushing pretreatment, the automation degree is improved, and the powder rate, surface metal pollution and water content of crushed silicon materials are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon rod crushing, in particular to a polysilicon rod crushing device after pretreatment. Background Art

[0002] Polysilicon is the basic material for producing solar cells and semiconductor components. The modified Siemens method of vapor deposition is the main method for producing polysilicon rods. The polysilicon produced by the vapor deposition method is a large rod. The polysilicon rod needs to be crushed to obtain block silicon material for drawing single crystal silicon rods, so it needs to be crushed into blocks before it can be used downstream. Pollution control and particle size management in the crushing and classification process of polysilicon rods are the focus of enterprises. The current process is to pre-treat the polysilicon with water quenching or thermal crushing and then crush it manually or mechanically at one time. This crushing method has the following problems:

[0003] 1. Manual crushing has the problems of high labor intensity and low efficiency. The cross contamination caused by sweat stains during the crushing process can easily cause the silicon material surface to be contaminated. The repeated knocking of polysilicon by the crushing hammer can easily introduce metal impurities, which affects the product quality. At the same time, due to the high hardness of the silicon rod, it cannot meet the needs of large-scale production.

[0004] 2. Mechanical one-time crushing will produce a large amount of polysilicon fine powder during the crushing process, with a high defective rate and a high increase in the value of metal impurities on the surface of polysilicon;

[0005] 3. After the polysilicon rods are pre-treated by water quenching or thermal crushing before being crushed, the residual moisture in the cracks cannot evaporate quickly and effectively. After the silicon material is bagged, water mist is generated in the bag, affecting the product quality. Utility Model Content

[0006] In view of the problems of large silicon material surface pollution, high powder rate, high moisture content, etc. in the existing technical solutions, the utility model provides a device for crushing polysilicon rods after pretreatment.

[0007] The utility model provides the following technical scheme: a device for crushing polysilicon rods after pretreatment, comprising a primary crushing device and a primary screening device connected in sequence, wherein the screened material discharge port of the primary screening device is connected to the secondary crushing device, the screened material discharge port of the primary screening device is connected to the secondary screening device, and the discharge port of the secondary crushing device is connected to the secondary screening device; a cooling conveying device is arranged between the primary crushing device and the primary screening device, and / or the screened material discharge port of the secondary screening device is connected to the cooling conveying device; the cooling conveying device comprises a conveyor and a steam collecting hood arranged on the top of the conveyor, wherein a feed port and a discharge hopper are respectively arranged at both ends of the conveyor, and the steam collecting hood is also provided with an exhaust port, and the exhaust port is connected to a fan through a pipeline.

[0008] Preferably, the discharge port of the primary crushing device is connected to a buffer material guiding device, and the discharge port of the buffer material guiding device is connected to the feed port of the cooling conveying device or the primary screening device.

[0009] Preferably, the underscreen discharge port of the primary screening device is connected to the secondary screening device via a chute.

[0010] Preferably, the conveyor is a belt conveyor, and the conveyor belt of the belt conveyor is a high temperature resistant conveyor belt.

[0011] The beneficial effects of the utility model are as follows: multi-stage crushing and screening are arranged, and a cooling and conveying device is combined to discharge moisture and lower the temperature, which is more suitable for the continuous production of crushing of polysilicon rods after water quenching or thermal crushing pretreatment, improves the degree of automation, and reduces the powder rate, surface metal pollution and moisture content of the silicon material after crushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is an equipment connection diagram of an embodiment of a crushing device.

[0013] Figure 2 A schematic diagram of an embodiment of a cooling conveying device.

[0014] Figure numerals: 10, primary crushing device; 11, buffering material guiding device; 20, primary screening device; 21, chute; 30, secondary crushing device; 40, secondary screening device; 50, cooling and conveying device; 51, conveyor; 52, steam hood; 53, feed inlet; 54, discharge hopper; 55, exhaust port. DETAILED DESCRIPTION

[0015] The following is a more detailed description of the implementation of the utility model in conjunction with the drawings and the figure marks, so that those skilled in the art can implement it after reading this specification. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not used to limit the utility model. Example

[0016] The utility model provides Figure 1-2A polysilicon rod pre-processing crushing device is shown, comprising a primary crushing device 10, the discharge port of the primary crushing device 10 is connected to a buffering guide device 11, the discharge port of the buffering guide device 11 is connected to a cooling conveying device 50, the discharge port of the cooling conveying device 50 is connected to a primary screening device 20, the screened material discharge port of the primary screening device 20 is connected to a secondary crushing device 30, the screened material discharge port of the primary screening device 20 is connected to a secondary screening device 40, and the discharge port of the secondary crushing device 30 is connected to the secondary screening device 40, and the screened material discharge port of the secondary screening device 40 is connected to the cooling conveying device 50. The connection to a certain device refers to the connection to the feed port of the device.

[0017] The polysilicon rods are first crushed into large-size blocks by the primary crushing device 10, which has the advantages of short crushing time and large particle size distribution, effectively shortening the process of repeated extrusion between the polysilicon rods and the crushing equipment, and repeated extrusion between the rods, reducing the increase of powder, equipment wear and metal impurities on the surface of the polysilicon contamination. The primary crushing device 10 can use a jaw crusher or other crushing machinery with a larger crushing size.

[0018] The material crushed by the primary crushing device 10 enters the buffering guide device 11 from its discharge port, which buffers the gravitational potential energy of the silicon material falling and plays a role of buffering, thereby solving the contradiction between the fast and scattered discharge of the primary crushing and the uniform material required by the cooling conveying device 50. The buffering guide device 11 can be a vibrating feeder or other feeding equipment.

[0019] The cooling conveying device 50 is used to reduce the temperature of the silicon material and accelerate the loss of water. Specifically, the cooling conveying device 50 includes a conveyor 51 and a steam collecting hood 52 arranged on the top of the conveyor 51. The two ends of the conveyor 51 are respectively provided with a feed port 53 and a discharge hopper 54. The steam collecting hood 52 is also provided with an exhaust port 55, and the exhaust port 55 is connected to a fan through a pipeline. The conveyor 51 can adopt a belt conveyor or other forms of conveyors, and its conveyor belt is a high-temperature resistant conveyor belt to increase the service life; the steam collecting hood 52 can be installed on the brackets on both sides of the conveyor 51, covering the top space of the conveyor belt to collect water vapor. The two ends of the conveyor 51 are respectively a feed end and a discharge end. The steam collecting hood 52 at the feed end is provided with a notch to form a feed port 53, and the discharge end is connected with a discharge hopper 54 to guide the silicon material to the next equipment. After the fan is started, negative pressure is formed, which promotes the accelerated flow of air from the feed port, discharge port and bottom of the conveyor to the exhaust port, strengthens the air flow near the silicon material, enhances the evaporation of water in the cracks of the silicon material, reduces the water content of the silicon material, and takes away the residual heat in the silicon material, reduces the high temperature resistance requirements of subsequent equipment, and meets the process temperature and water content requirements of subsequent processes; the residual heat of the silicon material also contributes to the evaporation of water in the cracks. In other embodiments, the fan can also form positive pressure.

[0020] After being processed by the cooling and conveying device 50, the silicon material enters the primary screening device 20 for classification. The qualified undersize material enters the secondary screening device 40 from the undersize material outlet through the chute 21, and the larger oversize material enters the secondary crushing device 30 from the oversize material outlet for further crushing, so as to avoid repeated crushing of the qualified silicon material resulting in increased powder rate and surface metal pollution; at the same time, the primary screening device 20 also has a buffering effect, making the discharge uniform, and reducing the processing capacity of the secondary crushing device 30, avoiding the accumulation of incoming materials in the secondary crushing process causing repeated extrusion and crushing, and further reducing the powder rate and surface metal pollution. The primary screening device 20 can use a tube screen or other screening equipment.

[0021] The silicon material after secondary crushing and the undersize material of the primary screening device 20 are merged into the secondary screening device 40 for secondary classification, and the oversize material enters another cooling and conveying device 50 to reduce the water content again, so that the water in the cracks of the silicon material can be fully evaporated, and the undersize material directly enters the next process. The installation height of the secondary screening device 40 is lower than that of the primary screening device 20, and a chute 21 needs to be added to the undersize material discharge port of the primary screening device 20 to connect to the secondary screening device 40. The secondary screening device 40 can use a multi-layer vibrating screen or other screening equipment. Example

[0022] The utility model provides a device for crushing polysilicon rods after pretreatment, which is the same as that of embodiment 1, but no cooling and conveying device 50 is arranged after the secondary screening device 40 . Example

[0023] The utility model provides a device for crushing polysilicon rods after pretreatment, which is the same as Example 1, but no cooling and conveying device 50 is arranged between the primary crushing device 10 and the primary screening device 20, the discharge port of the buffering material guiding device 11 is directly connected to the primary screening device 20, and a cooling and conveying device 50 is arranged after the secondary screening device 40.

[0024] The above are one or more embodiments of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A device for crushing polysilicon rods after pretreatment, characterized in that: It comprises a primary crushing device and a primary screening device which are connected in sequence, wherein the discharge port of the screened material of the primary screening device is connected to the secondary crushing device, the discharge port of the screened material of the primary screening device is connected to the secondary screening device, and the discharge port of the secondary crushing device is connected to the secondary screening device; a cooling conveying device is arranged between the primary crushing device and the primary screening device, and / or the discharge port of the screened material of the secondary screening device is connected to the cooling conveying device; the cooling conveying device comprises a conveyor and a steam collecting hood arranged on the top of the conveyor, a feed port and a discharge hopper are respectively arranged at both ends of the conveyor, the steam collecting hood is also provided with an exhaust port, and the exhaust port is connected to a fan through a pipeline.

2. The device for crushing polysilicon rods after pretreatment according to claim 1, characterized in that: The discharge port of the primary crushing device is connected to a buffer material guiding device, and the discharge port of the buffer material guiding device is connected to the feed port of the cooling conveying device or the primary screening device.

3. The device for crushing polysilicon rods after pretreatment according to claim 1, characterized in that: The underscreen discharge port of the primary screening device is connected to the secondary screening device through a chute.

4. The device for crushing polysilicon rods after pretreatment according to claim 1, characterized in that: The conveyor is a belt conveyor, and the conveyor belt of the belt conveyor is a high temperature resistant conveyor belt.

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