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Method for removing boron and phosphorus during production of polysilicon with improved siemens process

A Siemens method and polysilicon technology, applied in the field of polysilicon production, can solve problems such as unsatisfactory impurity removal effect, mass transfer, insufficient reaction, etc., and achieve the effect of reducing operating risks, improving the effect of rectification and separation, and saving equipment investment costs.

Inactive Publication Date: 2011-07-20
LESHAN LEDIAN TIANWEI SILICON TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to make full use of the by-product silicon tetrachloride, the silicon tetrachloride liquid containing solid impurities separated from the sedimentation tank needs special equipment to separate; the impurity removal reaction is carried out between gas and liquid, and neither mass transfer nor reaction Sufficient, the impurity removal effect is not ideal

Method used

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  • Method for removing boron and phosphorus during production of polysilicon with improved siemens process
  • Method for removing boron and phosphorus during production of polysilicon with improved siemens process
  • Method for removing boron and phosphorus during production of polysilicon with improved siemens process

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Effect test

Embodiment 1

[0026] Embodiment 1 Adopt the method of the present invention to produce trichlorosilane

[0027] Process flow chart such as figure 2 As shown, the syngas after dry dedusting (flow rate 200NM 3 / h, impurity content: boron 700ppb, phosphorus 500ppb), moisture (temperature: 32 ℃, humidity: 15% RH, flow: 25NM 3 / h) into the reactor respectively to react and spray silicon tetrachloride (flow rate: 1M 3 / h, temperature: 25°C), the impurity-containing silicon tetrachloride and the synthesis gas with high boilers collected from the reactor are first passed into the bubbler. The synthesis gas with high boilers enters the separator and is washed by silicon tetrachloride (temperature: 25°C) in the separator. The impurity content in the purified synthesis gas is: boron 400ppb, phosphorus 300ppb, purified The synthesis gas enters the condensation recovery system and undergoes cryogenic cooling (temperature: -50°C) to obtain silicon tetrachloride condensate. The silicon tetrachloride ...

Embodiment 2

[0029] Embodiment 2 Adopt the method of the present invention to produce trichlorosilane

[0030] Process flow chart such as figure 2 As shown, the syngas after dry dedusting (flow rate 100NM 3 / h, impurity content: boron 700ppb, phosphorus 500ppb), humidity (temperature: 25°C, humidity: 8% RH, flow: 15NM 3 / h) into the reactor to react and spray silicon tetrachloride (flow rate: 0.5M 3 / h, temperature: 25°C), the impurity-containing silicon tetrachloride and the synthesis gas with high boilers collected from the reactor are first passed into the bubbler. The synthesis gas with high boilers enters the separator and is washed by silicon tetrachloride (temperature: 25°C) in the separator. The impurity content in the purified synthesis gas is: boron 380ppb, phosphorus 200ppb, purified The synthesis gas enters the condensation recovery system and undergoes cryogenic cooling (temperature: -50°C) to obtain silicon tetrachloride condensate. The silicon tetrachloride condensate i...

Embodiment 3

[0032] Embodiment 3 Adopt the method of the present invention to produce trichlorosilane

[0033] Process flow chart such as figure 2 As shown, the syngas after dry dedusting (flow rate 230NM 3 / h, impurity content: boron 700ppb, phosphorus 500ppb), humidity (temperature: 34 ℃, humidity: 20% RH, flow: 25NM 3 / h) respectively pass into the reactor to react and spray silicon tetrachloride (flow rate: 1.2M 3 / h, temperature: 25°C), the impurity-containing silicon tetrachloride and the synthesis gas with high boilers collected from the reactor are first passed into the bubbler. The synthesis gas with high boilers enters the separator and is washed by silicon tetrachloride (temperature: 25°C) in the separator. The impurity content in the purified synthesis gas is: boron 450ppb, phosphorus 310ppb, purified The synthesis gas enters the condensation recovery system and undergoes cryogenic cooling (temperature: -50°C) to obtain silicon tetrachloride condensate. The silicon tetrachl...

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Abstract

The invention relates to a method for removing boron and phosphorus during the production of polysilicon with the improved siemens process, belonging to the filed of the production of polysilicon and aiming at providing a method for removing boron and phosphorus during the production of polysilicon with the improved siemens process with low cost and a method for producing trichlorosilane with lowcost. The method for removing boron and phosphorus during the production of polysilicon with the improved siemens process comprises the following steps: a, making silicon powder react with hydrogen chloride to generate trichlorosilane synthesis gas, and dedusting the trichlorosilane synthesis gas with dry method; b, making the dedusted trichlorosilane synthesis gas fully react with moisture, and spraying or leading the generated gas into silicon tetrachloride liquid to generate liquid phase 1 and gas phase 1; and c, putting the gas phase 1 in a separator, washing and separating the gas phase 1 with the silicon tetrachloride liquid to obtain the purified trichlorosilane synthesis gas and liquid phase 2. The invention saves the cost of the investment on equipment in the polysilicon plant and provides a novel method for removing boron, phosphorus and other impurities with the improved siemens process.

Description

technical field [0001] The invention relates to a method for removing boron and phosphorus in an improved Siemens process for producing polysilicon, and belongs to the field of polysilicon production. Background technique [0002] Polysilicon production is a process of producing high-purity silicon blocks from industrial silicon. The purpose of the process is to remove boron, phosphorus and metal impurities in silicon. The improved Siemens method is to synthesize trichlorosilane by reacting silicon powder with hydrogen chloride. After the trichlorosilane is purified by rectification to reach the specified purity, polysilicon is prepared by hydrogen reduction, the reduction tail gas is recovered, and the trichlorosilane, hydrogen, and hydrogen chloride in the tail gas are returned to the system for recycling, thus forming a closed-circuit cycle of materials and comprehensive material synthesis. Clean production process of recycling. [0003] The current production process o...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/03C01B33/107
Inventor 唐前正何劲李钊郭勇赵伯君
Owner LESHAN LEDIAN TIANWEI SILICON TECH CO LTD