Preparation method for purifying silicon raw material by using hyper-gravity rotating packed bed

Abstract

The invention provides a preparation method for purifying silicon raw material by using a hyper-gravity rotating packed bed. According to the invention, first, liquid state silicon raw material, impurity steam, other chlorosilane or silane are delivered though a first hyper-gravity rotating packed bed packed with metallic sponge under a temperature lower than the boiling point of the silicon raw material, such that the impurity steam and other chlorosilane or silane are separated from the liquid state silicon raw material; second, the liquid state silicon raw material is delivered into a second hyper-gravity rotating packed bed, and oxygen is also delivered into the second hyper-gravity rotating packed bed, such that silicon hydroxide compounds containing impurities are obtained, wherein the silicon hydroxide compounds have a relatively high boiling point; last, the silicon hydroxide compounds containing impurities are removed from the silicon raw material through fractionation. With the purifying technology provided by the invention, high product purity can be achieved without multiple fractionations and high temperature reactions which cost time and investment.

Description

technical field [0001] The present invention relates to a manufacturing method for purifying silicon raw materials, particularly a manufacturing method for purifying trichlorosilane or a mixture of trichlorosilane and silicon tetrachloride with a supergravity rotating packed bed. Background technique [0002] Electronic grade polysilicon (EGS) can be obtained from trichlorosilane or a mixture of trichlorosilane and silicon tetrachloride from which impurities such as boron and phosphorus are removed. Most impurities can be removed immediately by fractional distillation. Trace impurities such as boron and phosphorus are usually treated as BCl 3 , PCl 3 , B 2 H 6 or PH 3 exist in the form of fractional distillation, but reducing these contaminations to acceptably low levels by fractional distillation requires several successive fractional distillation steps. The main reason is that the bubbles of the impurity gas are not easily removed from the liquid trichlorosilane and ...

AI Technical Summary

Problems solved by technology

U.S. Patent No. 4,283,255 to Ramshaw et al. proposes a process and equipment for high-efficiency mass transfer between two liquids on a rotary table, but there is no prior art that uses a rotary table to remove impurities from silicon raw materials

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