Silicon tetrachloride purification method and apparatus thereof

A technology for purifying silicon tetrachloride and polytetrafluoroethylene, applied in the direction of halogenated silicon compounds, halogenated silanes, etc., can solve the problems of large equipment investment, large photon transmission loss, complex process, etc., to reduce height and increase contact Large area, strong anti-corrosion effect

Active Publication Date: 2012-07-04
HUBEI JINGXING SCI & TECH INC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But due to the crude SiCl 4 The boiling point of the middle impurity dichlorodihydrosilane and trichlorosilane is similar to that of silicon tetrachloride, and the photon transmission loss is relatively large
Due to the limitation of the separation effect of the packing, the traditional rectification column must reach 60-70 meters to separate it. Not only is the process complicated, but also the equipment investment is relatively large. At present, there are reports of domestic industrialization by Wuhan New Silicon Technology Co., Ltd.

Method used

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  • Silicon tetrachloride purification method and apparatus thereof
  • Silicon tetrachloride purification method and apparatus thereof
  • Silicon tetrachloride purification method and apparatus thereof

Examples

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Effect test

Embodiment 1

[0024] Embodiment 1: rectification packed tower

[0025] see figure 1 . The height of the packed tower is 8.6m, of which the packing part is 6m high and 0.76m in diameter, and the tower shell is made of 316L stainless steel. The rectification tower includes a tower shell, light radiation air cooler packing, packing support device and heating device (0.7m in height, 0.4m in diameter). Cylindrical packing is evenly placed upright on the packing support device in the tower, and each layer of packing support device Put 500 cylindrical fillers on top, the fillers are made of poly-p-phenylene terephthalamide fibers, polytetrafluoroethylene, and 316L steel. formamide fiber and polytetrafluoroethylene. The outer diameter of the outer shell of the cylindrical filler is 3mm, and a hollow polytetrafluoroethylene cylinder is coaxially placed inside. The wall thickness of the cylinder is 0.4mm, and the inner diameter is 1.5mm. The middle and outer sides of the cylinder are filled with p...

Embodiment 2

[0028] The raw material is crude silicon tetrachloride separated from the by-products of polysilicon production, the purity of which is 99.5%, and it is purified by rectification. The incoming material first passes through the silica gel adsorption column, and then enters the rectification tower. After 8 hours of total reflux, the temperature at the top of the tower is controlled to reach 53-55°C, and when the temperature of the tower kettle reaches 60-65°C, the material starts to be discharged. The reflux ratio is 20:1, and the intermediate product obtained from the middle outlet is the obtained high Pure tetrachlorosilicon product, packaged after condensation. Impurities such as trichlorosilane produced by rectification are discharged from the tail gas outlet.

[0029] In the product, the purity of silicon tetrachloride reaches ppb level, and the impurity content is: W Cr = 0.05ppb; W Fe = 2ppb; W co = 0.1ppb; W cu = 0.1ppb; W Mn = 0.02ppb; W Ni = 1.5ppb; W V = 0.5pp...

Embodiment 3

[0032]The raw material is crude silicon tetrachloride separated from the by-products of polycrystalline production, the purity of which is 99.4%, and it is purified by rectification. The incoming material first passes through the silica gel adsorption column, and then enters the rectification tower. After 9 hours of full reflux, the temperature at the top of the tower is controlled to reach 51-52°C, and when the temperature of the tower kettle reaches 65-70°C, the material starts to be discharged. The reflux ratio is 30:1, and the intermediate product obtained from the middle outlet is the obtained high Pure tetrachlorosilicon product, packaged after condensation. Impurities such as trichlorosilane produced by rectification are discharged from the tail gas outlet.

[0033] In the product, the purity of silicon tetrachloride reaches ppb level, and the impurity content in it is: W Cr = 0.08ppb; W Fe = 3ppb; W co = 0.4ppb; W cu = 0.6ppb; W Mn = 0.06ppb; W Ni = 1.6ppb; W V...

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Abstract

A columnar packing comprises a stainless steel columnar casing, which is filled with poly(p-phenylene terephthalamide) fibers and a polytetrafluoroethylene hollow cylinder. The casing of the columnar packing is made of stainless steel; the polytetrafluoroethylene hollow cylinder is coaxially placed in the stainless steel casing; and the space between the stainless steel casing and the polytetrafluoroethylene hollow cylinder is filled with poly(p-phenylene terephthalamide) fibers. A silicon tetrachloride purification method is achieved by rectification in a rectification column with a column top temperature of 50 to 55 DEG C during rectification and a reflux ratio of (10:1) to (30:1) when the column bottom temperature reaches 60 to 70 DEG C. The columnar packing is selected as the packing of the rectification column to lengthen the gas-liquid exchanging path, increase the contact area, and improve the theoretical stage number in each meter of column height to 50, so that trichlorosilane can be removed effectively by designing a rectification column with a height of 6 to 9 meters, thereby obtaining fiber-level silicon tetrachloride.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and in particular relates to a method for purifying silicon tetrachloride and equipment thereof. Background technique [0002] The by-product of polysilicon is mainly silicon tetrachloride, and untreated crude silicon tetrachloride is a highly corrosive poisonous and harmful liquid, which is very harmful to safety and the environment. In 2011, my country's polysilicon production capacity will expand to about 100,000 tons. According to the current domestic best control level, the production of 1,000 tons of polysilicon will produce 15,000 tons of crude silicon tetrachloride. In the past few years, the total domestic production of polysilicon was not large, and the problem of silicon tetrachloride was not prominent. Once the total domestic polysilicon production exceeds 100,000 tons, silicon tetrachloride will become a major problem restricting the development of polysilicon. Therefore...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/107
Inventor 戴百雄宫廷吴勇徐善武张建广罗斌温志鹏
Owner HUBEI JINGXING SCI & TECH INC CO LTD
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