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Method for low-temperature hydrolysis of silicon tetrachloride

A silicon tetrachloride, low temperature technology, applied in the direction of silicon oxide, silicon dioxide, etc., can solve the problem of no good solution and approach, and achieve the effect of low requirements, prolonging service life and ensuring purity

Inactive Publication Date: 2013-01-23
河北东明中硅科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There has been no good solution and way in the industry

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] (1) Add silicon tetrachloride liquid into the vaporizer, and heat the vaporizer with 170°C heat conduction oil to obtain vaporized silicon tetrachloride.

[0026] (2) Pass the vaporized silicon tetrachloride into the hydrolysis tower for submerged bubbling hydrolysis to obtain a hydrolyzed mixture. The liquid level in the tower is 2.5 meters, and put the hydrolyzed mixture into a buffer tank. The outlet pipe of the hydrolysis tower enters the buffer tank vertically.

[0027] (3) Use a pump to transport the hydrolyzed mixture to a first-stage diaphragm underflow filter press for the first pressure filtration to obtain a press-filtered filter cake and filtrate, and transport the filtrate to a hydrolysis tower for four Silicon chloride is hydrolyzed until the mass concentration of HCl reaches 25% in the resulting filtrate to obtain hydrochloric acid.

[0028] (4) Transport the filter cake to a colloid mill for grinding until no lumps exist.

[0029] (5) Transfer the grou...

Embodiment 2

[0036] (1) Add silicon tetrachloride liquid into the vaporizer, heat the vaporizer with 190°C heat conduction oil to obtain vaporized silicon tetrachloride.

[0037] (2) Pass the vaporized silicon tetrachloride into the hydrolysis tower for submerged bubbling hydrolysis to obtain the hydrolyzed mixture, the liquid level in the tower is 2 meters, and put the hydrolyzed mixture into the buffer tank. The outlet pipe of the hydrolysis tower enters the buffer tank vertically.

[0038] (3) Use a pump to transport the hydrolyzed mixture to a first-stage diaphragm underflow filter press for the first pressure filtration to obtain a press-filtered filter cake and filtrate, and transport the filtrate to a hydrolysis tower for four Silicon chloride is hydrolyzed until the mass concentration of HCl reaches 20% in the resulting filtrate to obtain hydrochloric acid.

[0039] (4) Transport the filter cake to a colloid mill for grinding until no lumps exist.

[0040] (5) Transfer the ground...

Embodiment 3

[0047] (1) Add silicon tetrachloride liquid into the vaporizer, and heat the vaporizer with 180°C heat conduction oil to obtain vaporized silicon tetrachloride.

[0048] (2) Pass the vaporized silicon tetrachloride into the hydrolysis tower for submerged bubbling hydrolysis to obtain a hydrolyzed mixture. The liquid level in the tower is 3 meters, and put the hydrolyzed mixture into a buffer tank. The outlet pipe of the hydrolysis tower enters the buffer tank vertically.

[0049] (3) Use a pump to transport the hydrolyzed mixture to a first-stage diaphragm underflow filter press for the first pressure filtration to obtain a press-filtered filter cake and filtrate, and transport the filtrate to a hydrolysis tower for four Silicon chloride is hydrolyzed until the mass concentration of HCl in the resulting filtrate reaches 30%, to obtain hydrochloric acid.

[0050] (4) Transport the filter cake to a colloid mill for grinding until no lumps exist.

[0051] (5) Transfer the groun...

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PUM

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Abstract

The invention discloses a method for the low-temperature hydrolysis of silicon tetrachloride, which comprises: hydrolyzing gasified silicon tetrachloride; subjecting a mixture obtained after hydrolysis to pressure filtration; delivering filtrate to a hydrolysis tower, hydrolyzing silicon tetrachloride till the HCl mass concentration in the filtrate reaches 20 to 30 percent and obtaining hydrochloric acid; grinding filter cakes till there are not blocks; washing ground mixture with water and pulping; performing secondary pressure filtration, returning part of filtrate to the hydrolysis tower to hydrolyze the silicon tetrachloride, neutralizing the other part of filtrate and discharging the part of neutralized filtrate into a waste water tank; and drying and flashing the filter cakes obtained b secondary pressure filtration, and obtaining the final silicon dioxide product by cyclonic separation. In the invention, the equipment requirement is low, the energy consumption is low and pollution is little; the silicon tetrachloride is hydrolyzed more fully; the blockage of pipe lines due to silica gel accumulation and uncontrollable flow rate is avoided; and the service life of the equipment is prolonged.

Description

technical field [0001] The invention relates to a low-temperature hydrolysis method of silicon tetrachloride. Background technique [0002] Silicon tetrachloride is a by-product of polysilicon production. Polysilicon is the main raw material required by the electronics industry and photovoltaic industry. In the production of polysilicon, for every ton of polysilicon produced, 15 tons of silicon tetrachloride need to be processed. The processing capacity Very big. Untreated silicon tetrachloride is a highly corrosive chemical. It releases heat when heated or meets moisture, and releases toxic and corrosive fumes, which are extremely harmful to the environment. [0003] With the development of the photovoltaic industry in the world and my country, the demand for solar cells is increasing, the output of polysilicon is increasing year by year, and the environmental problems and resource utilization problems caused by the by-product silicon tetrachloride are becoming increasingl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/12
Inventor 杨刊常召雷董永明
Owner 河北东明中硅科技有限公司