System and method for filtering chlorosilane residual liquid

Abstract

The invention discloses a system and a method for filtering chlorosilane residual liquid, wherein the system comprises a stirrer, a nitrogen storage tank, a filter and a chlorosilane raffinate storagetank; the stirrer is provided with a diatomite inlet, a silicon tetrachloride inlet and a mixture outlet; the nitrogen storage tank is connected with the stirrer through a first pipeline, and a firstvalve is arranged on the first pipeline; a liquid purifying cavity, a filtering cavity and a feeding cavity are defined in the filter from top to bottom; a filter element arranged in the axial direction of the filter cavity is arranged in the filter cavity, the lower end of the filter element is closed, the side wall of the filter element is wrapped with filter cloth, an upper port of the filterelement communicates with the liquid purifying cavity, a differential pressure detection device is arranged between the liquid purifying cavity and the feeding cavity, and the liquid purifying cavityis provided with a chlorosilane clear liquid outlet; the mixture outlet communicates with the feeding cavity through a second pipeline; the chlorosilane residual liquid storage tank is connected withthe feeding cavity through a third pipeline, and a third valve is arranged on the third pipeline. By adopting the system, the problems that amorphous silicon and aluminum chloride precipitates in chlorosilane residual liquid are difficult to filter and the filtering cost is high in the prior art can be solved.

Description

technical field [0001] The invention belongs to the field of polysilicon, and in particular relates to a filtration system and method for chlorosilane raffinate. Background technique [0002] A large amount of by-product silicon tetrachloride is produced during the production of polysilicon by the improved Siemens method. At present, more than 90% of polysilicon enterprises adopt silicon tetrachloride cold hydrogenation technology to treat by-products and convert them into trichlorosilane, the raw material for polysilicon production. Silicon tetrachloride cold hydrogenation technology is to react metallurgical-grade silicon powder, hydrogen, and silicon tetrachloride under the action of a catalyst under certain temperature and pressure conditions to generate trichlorosilane. Since metallurgical grade silicon powder contains metal impurities, fine silicon powder and metal impurities are introduced into the hydrogenation product (chlorosilane). In the quenching tower or rins...

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Problems solved by technology

For this reason, an object of the present invention is to propose a kind of filtration system and method of chlorosilane raffinate, adopt this system to solve the difficult filtration and filtration cost of amorphous silicon and aluminum chloride precipitate in chlorosilane raffinate in the prior art high problem

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