Purification method and purification system of chlorosilicate

A purification method and silicide technology, which is applied in the direction of silicon halide compounds, halosilanes, etc., can solve problems such as difficulty in effectively reducing the impurity concentration of chlorosilicides, and achieve the goal of avoiding unqualified polysilicon quality, good separation effect, and high separation efficiency Effect

Active Publication Date: 2017-06-23
CHINA SILICON CORP LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The main purpose of the present invention is to provide a purification method and purification system of chlorosilicides, so as to solve the problem that the purification methods in the prior art are difficult to effectively reduce the impurity concentration in chlorosilicides

Method used

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  • Purification method and purification system of chlorosilicate

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Effect test

Embodiment 1

[0050] Put the trichlorosilane raw material into the first rectification tower, the B impurity content is 20ppb, the P impurity content is 13ppb, the pressure of the tower is controlled at 0.2MPa, and the temperature of the tower kettle is at 50°C to ensure the reflux of the tower, and the product is extracted from the tower kettle The rectification liquid phase trichlorosilane enters the reaction adsorber; the adsorption reactor is controlled at 20KPa, the temperature inside the adsorption reactor is controlled to be 35°C, and the rectification liquid phase trichlorosilane enters the adsorption reactor from the bottom of the first rectification tower In the reactor, a packed bed is set in the adsorption reactor, and an adsorbent is arranged in the packed bed, wherein the main body of the adsorbent is porous silica gel, the free water content is 10%, the aspect ratio of the equipment is controlled at 15:1, and the top outlet is adsorbed Liquid phase trichlorosilane; the gas pha...

Embodiment 2

[0052] Put the trichlorosilane raw material into the first rectification tower, the B impurity content is 22ppb, the P impurity content is 15ppb, the pressure of the tower is controlled at 0.3MPa, and the temperature of the tower kettle is at 65°C to ensure the reflux of the tower, and the product is extracted from the tower kettle The rectification liquid phase trichlorosilane enters the reaction adsorber; the adsorption reactor is controlled at 10KPa, the temperature inside the adsorption reactor is controlled at 10°C, and the rectification liquid phase trichlorosilane enters the adsorption reactor from the bottom of the first rectification tower In the reactor, a packed bed is set in the adsorption reactor, and an adsorbent is arranged in the packed bed, wherein the main body of the adsorbent is porous silica gel, the free water content is 10%, the aspect ratio of the equipment is controlled at 10:1, and the top outlet is adsorbed Gas-phase trichlorosilane; the adsorbed liqu...

Embodiment 3

[0054] Put the trichlorosilane raw material into the first rectification tower, the B impurity content is 23ppb, the P impurity content is 12ppb, the pressure of the tower is controlled at 0.05MPa, and the temperature of the tower kettle is at 45°C to ensure the reflux of the tower, and the product is extracted from the tower kettle The rectification liquid phase trichlorosilane enters the reaction adsorber; the adsorption reactor is controlled at 50KPa, the temperature inside the adsorption reactor is controlled at 45°C, and the rectification liquid phase trichlorosilane enters the adsorption reactor from the bottom of the first rectification tower In the reactor, a packed bed is set in the adsorption reactor, and an adsorbent is arranged in the packed bed, wherein the main body of the adsorbent is porous silica gel, the free water content is 2%, the aspect ratio of the equipment is controlled at 20:1, and the top outlet is adsorbed Gas-phase trichlorosilane; the adsorbed liqu...

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Abstract

The invention provides a purification method and purification system of chlorosilicate. The chlorosilicate is dichlorosilane, trichlorosilane or silicon tetrachloride containing boron and phosphorus impurities. The purification method comprises the following steps: step S1, performing primary rectification on the chlorosilicate to obtain rectified liquid-phase chlorosilicate; step S2, processing the rectified liquid-phase chlorosilicate by utilizing an absorbent to obtain absorbed liquid-phase chlorosilicate, wherein the absorbent has free water or crystallized water, the free water or the crystallized water has hydrolytic reaction with the boron and phosphorus impurities to generate high-boiling residues, wherein a part of the high-boiling residues exist in the absorbed liquid-phase chlorosilicate; and step S3, performing secondary rectification on the absorbed liquid-phase chlorosilicate to obtain purified chlorosilicate. The water in the absorbent has hydrolytic reaction with the boron and phosphorus impurities to generate the high-boiling residues, the high-boiling residues are easily separated from the chlorosilicate, so that the separation efficiency is relatively high; and the purification method is relatively good in separation effect, and content of the boron and phosphorus impurities in the purified chlorosilicate can be 0.05 to 0.5 ppb.

Description

technical field [0001] The invention relates to the field of chlorosilane treatment, in particular to a purification method and a purification system of chlorosilanes. Background technique [0002] In the production of polysilicon by the improved Siemens process, the purity of trichlorosilane raw material is one of the important factors affecting the quality of polysilicon. At present, the impurity content in the material is basically controlled by means of rectification and purification. [0003] Impurities such as boron and phosphorus introduced from silicon powder in the synthesis of trichlorosilane exist in the form of complex compounds in chlorosilane, and its boiling point is very close to that of trichlorosilane. It is difficult to remove impurities by conventional purification methods. Control at a very low level. At present, the product quality is basically controlled by multi-stage rectification at home and abroad. In this way, the energy consumption and investment...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/107
Inventor 刘见华赵雄万烨姜丽霞王芳严大洲杜俊平张晓伟张升学
Owner CHINA SILICON CORP LTD
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