Method and device for purifying trichlorosilane

A technology of trichlorosilane and purification method, which is applied in the direction of halosilane and silicon halide compounds, which can solve the problems of high equipment requirements and inability to meet electronic grade polysilicon, so as to avoid secondary pollution, reduce energy consumption, and reduce costs Effect

Inactive Publication Date: 2010-05-26
GUODIAN NINGXIA SOLAR
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method has high requirements on equipment, and the boron and phosphorus content of 10ppb still cannot meet the requirements of electronic grade polysilicon

Method used

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  • Method and device for purifying trichlorosilane
  • Method and device for purifying trichlorosilane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0065] The raw material is crude chlorosilane, which contains 80ppma of boron trichloride, 50ppma of phosphorus trichloride, 80% of trichlorosilane, and the rest is other impurities.

[0066] The crude chlorosilane is continuously added to tower 1 at a flow rate of 1000kg / h, and the operating conditions of tower 1 are as follows:

[0067] The operating pressure is 0.2MPa, the temperature at the top of the tower is 55°C, the temperature at the bottom of the tower is 88°C, and the reflux ratio is 3.

[0068] Cut off the top fraction of 800kg / h and add it to tower 2, and the bottom fraction of 200kg / h will be collected and processed separately.

[0069] The operating conditions of column 2 are as follows: the operating pressure is 0.2 MPa, the temperature at the top of the column is 51° C., the temperature at the bottom of the column is 60° C., and the reflux ratio is 3100.

[0070] The 798kg / h bottom fraction of interception tower 2 enters tower 3, and the tower top fraction of...

Embodiment 2

[0076] The raw material is crude chlorosilane, which contains 60ppma of boron trichloride, 30ppma of diborane, 50ppma of phosphorus trichloride, 80% of trichlorosilane, and the rest is other impurities.

[0077] The crude chlorosilane is continuously added to tower 1 at a flow rate of 2000kg / h, and the operating conditions of tower 1 are as follows:

[0078] The operating pressure is 0.10MPa, the temperature at the top of the tower is 32°C, the temperature at the bottom of the tower is 70°C, and the reflux ratio is 9.

[0079] Cut off the top fraction of 1600kg / h and add it to tower 2, and the bottom fraction of 400kg / h will be collected and processed separately.

[0080] The operating conditions of column 2 are as follows: the operating pressure is 0.10 MPa, the temperature at the top of the column is 31° C., the temperature at the bottom of the column is 45° C., and the reflux ratio is 7500.

[0081] The 1596kg / h bottom fraction of interception tower 2 enters tower 3, and t...

Embodiment 3

[0087] The raw material is crude chlorosilane, which contains 80ppma of boron trichloride, 50ppma of phosphorus trichloride, 20ppma of phosphorus pentachloride, contains 80% of trichlorosilane, and the rest is other impurities.

[0088] The crude chlorosilane is continuously added to tower 1 at a flow rate of 1000kg / h, and the operating conditions of tower 1 are as follows:

[0089] The operating pressure is 0.25MPa, the temperature at the top of the tower is 62°C, the temperature at the bottom of the tower is 100°C, and the reflux ratio is 5.

[0090] Cut off the top fraction of 800kg / h and add it to tower 2, and the bottom fraction of 200kg / h will be collected and processed separately.

[0091]The operating conditions of column 2 are as follows: the operating pressure is 0.25MPa, the temperature at the top of the tower is 60°C, the temperature at the bottom of the tower is 66°C, and the reflux ratio is 7000.

[0092] The 798kg / h bottom fraction of interception tower 2 enter...

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Abstract

The invention discloses a method for purifying trichlorosilane, which comprises the following steps: a) sending raw material liquid containing trichlorosilane into a first distillation column for distillation and separating a first part of impurities from the raw material liquid, wherein the relative volatility of trichlorosilane relative to the first part of impurities is 1.6 to 2.5; b) sending overhead fractions of the first distillation column into a second distillation column for distillation and separating a second part of impurities from the overhead fractions, wherein the relative volatility of the second part of impurities relative to trichlorosilane is 1.4 to 1.7; and c) sending column-bottom fractions of the second distillation column into a third distillation column for distillation and separating the second part of impurities from the column-bottom fractions, wherein the reflux ratio of the third distillation column is greater than that of the second distillation column. Experimental results show that the boron content of trichlorosilane can be reduced to 0.01 ppba and the phosphorus content of trichlorosilane can be reduced to 0.1 ppba according to the method provided by the invention.

Description

technical field [0001] The invention relates to the technical field of rectification and purification, in particular to a method for purifying trichlorosilane. Background technique [0002] Trichlorosilane is also known as silicon chloroform, silicon form or trichlorosilane, English name: trichlorosilane or siliconochloroform, molecular formula is SiHCl 3 , which is a polar substance, is used in the synthesis of organosilanes, and is also the main raw material for the production of polysilicon. [0003] With the development of industries such as electronic devices, integrated circuits, and solar energy, the production scale of polysilicon continues to expand, and industrial production has higher and higher requirements for its purity. At present, polysilicon is mostly obtained by reducing trichlorosilane with hydrogen, and industrially produced trichlorosilane generally contains more than 20 kinds of impurities, which will affect the purity of polysilicon. Therefore, the p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/107
Inventor 樊志明张滨泉崔雷孟庆库
Owner GUODIAN NINGXIA SOLAR
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