Recovery method of waste chlorsilane in polysilicon produced through modified Simens Method

Abstract

The invention relates to a recovery method of waste chlorsilane in polysilicon production through an improved Simens Method, which belongs to the production field of the polysilicon, and comprises the following steps that: 1) collecting waste chlorsilane to be transported to a liquid storage tank; 2) conveying the waste chlorsilane in the liquid storage tank to an evaporator; 3) heating the evaporator: the evaporator is heated to 30 DEG C to 180 DEG C, so the chlorsilane inside the evaporator is vaporized to produce the chlorsilane steam, and residual liquid in the evaporator is hydrolyzed; 4) enabling the vaporized chlorsilane to be reacted with damp air, and foreign matters are reacted to generate high-boiling residues; and 5) recycling gas: micro solid foreign matters in the gas are eliminated through the gas-solid separation, and the chlorsilane is condensed to recycle. By adopting the method, the foreign matters in the polluted chlorsilane with high content of foreign matters in the production process can be eliminated, so the requirement on the foreign matter content in the chlorsilane raw material in the process that the improved Simens Method is used for producing the polysilicon can be satisfied; and the cost is low, environmental protection can be realized and no additional equipment is required.

Description

technical field

[0001] The invention relates to a method for recovering waste chlorosilane in polysilicon production by the improved Siemens process, and belongs to the field of polysilicon production. Background technique

[0002] The current production process of trichlorosilane, the raw silicon powder enters the synthesis furnace through the silicon powder feeding system and reacts with hydrogen chloride to generate trichlorosilane, and simultaneously generates silicon tetrachloride, dichlorodihydrosilane, metal chloride, polychloride Silane, hydrogen and other by-products, this mixed gas is called trichlorosilane synthesis gas. When the trichlorosilane synthesis gas comes out of the furnace, it will carry a small amount of silicon powder. After removing part of the silicon powder through a dry dust removal system (such as a bag dust removal system, etc.), it is sent to a wet dust removal system and washed by silicon tetrachloride liquid. The discharged chlorosilane wast...

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