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Method for purification of dichlorosilane from dry method recovered material

A dry recovery technology for dichlorodihydrosilane, which is applied in the direction of halosilane and halide silicon compounds, can solve the problems of multiple theoretical plates and reflux ratios, large heat loads, and difficulties in removing impurities in the separation tower, and reduce the The effect of production cost, equipment cost reduction and purification energy consumption reduction

Active Publication Date: 2012-11-28
CHINA ENFI ENGINEERING CORPORATION +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

From the perspective of the difficulty of separation, the boiling points of dichlorodihydrosilane and low boilers are very close, and it is very difficult to remove impurities with a separation tower, which requires a considerable number of theoretical plates and reflux ratios, which requires a large amount of heat load

Method used

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  • Method for purification of dichlorosilane from dry method recovered material
  • Method for purification of dichlorosilane from dry method recovered material
  • Method for purification of dichlorosilane from dry method recovered material

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Embodiment 1

[0037] Adopt the method for purifying dichlorodihydrosilane according to the present invention, utilize such as figure 2 The flow chart shown carries out the purification of dichlorodihydrosilane.

[0038] The dry reclaimed material in the polysilicon production process is sent to the first dry rectification tower for rectification, and the processing capacity of the first dry rectification tower is controlled to be 15m 3 / h.

[0039] 0.1~0.5m 3 The extraction speed of / h extracts the first low boiler after rectification from the top of the first dry distillation column, and discharges the intermediate chlorosilane from the bottom of the column. The first low boiler contains dichlorodihydrogen silicon and boron-containing impurities.

[0040] The first low boiling point is 0.1 ~ 0.5m 3 / h speed into the separation tower for separation, and 0.1 ~ 0.45m 3 The speed of / h extracts dichlorodihydrosilane from the bottom of the separation tower, and extracts a small amount of ...

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Abstract

The invention discloses a method for purification of dichlorosilane from dry method recovered materials, and comprises the following steps of: a) obtaining a dry-method recovered material by recovering from reduction tail gas of the polysilicon production process by a dry method, feeding the recovered material into a first dry method rectifying tower for rectification, recovering a first low-boiling-point substance from the tower top of the first dry method rectifying tower, and recovering intermediate chlorosilane from the tower bottom of the first dry method rectifying tower; b) feeding the first low-boiling-point substance into a separation column for separation, recovering boron impurity from the top of the separation column, and recovering dichlorosilane from the bottom of the separation column; c) feeding the intermediate chlorosilane into a second dry method rectifying tower for rectification, recovering a second low-boiling-point substance from the tower top of the second dry method rectifying tower, and recovering silicon tetrachloride from the tower bottom of the second dry method rectifying tower. According to the method of the invention, the second low-boiling-point substance is a mixture of dichlorosilane and trichlorosilane which can be directly fed into a reducing furnace for reduction reaction, thereby saving the process of mixing the dichlorosilane and the trichlorosilane.

Description

technical field [0001] The invention relates to the technical field of polysilicon, more specifically, the invention relates to a method for purifying dichlorodihydrogen silicon from dry recycled materials. Background technique [0002] Dichlorodihydrosilane, a by-product of polysilicon, has a unique low boiling point, flammable and explosive characteristics, which have become a technical bottleneck for polysilicon enterprises to expand production. The traditional treatment method has brought many problems not only in terms of safety, but also in terms of environmental protection; The purification process of chlorodihydrosilane is the key to determine whether it can be recycled in the future. [0003] In the process of producing polysilicon by the improved closed Siemens method, 1.6 tons of dichlorodihydrogen silicon will be produced for every ton of polysilicon produced. With the continuous expansion of scale, the current polysilicon factory is to pass the purified dichlor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/107
Inventor 姜利霞严大洲毋克力肖荣晖汤传斌杨永亮
Owner CHINA ENFI ENGINEERING CORPORATION
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