Production process of high-purity refined trichlorosilane

Abstract

The invention relates to the field of rectification and purification; at present, a conventional multi-stage rectification technology is adopted in existing polycrystalline silicon production to purify trichlorosilane, rectification stages are multiple, reflux ratio is large, energy consumption is large and device investment is high; in order to overcome the problems, a technical scheme in the invention adopts a novel process of combining resin adsorption with multi-stage rectification. Coarse trichlorosilane is pre-cooled and cooled, and pumped into an adsorbing device with special divinylbenzene resin by a pump to remove boron and phosphor impurities; and then, rectification is carried out on the adsorbed trichlorosilane liquor in a three-level rectification tower to obtain the high-purity trichlorosilane. The production process disclosed by the invention not only achieves the purpose in the invention, but also has high trichlorosilane purity, lower rectification separator impurity content and can recycle the trichlorosilane for use in disproportionated reaction, so that energy consumption is further lowered, and material utilization rate is improved.

Description

technical field [0001] The invention relates to the technical field of rectification and purification, in particular to a method for adsorption and rectification of crude trichlorosilane and a device thereof. Background technique [0002] Nowadays, the production method of polysilicon is mainly the improved Siemens method. The improved Siemens method is to convert metallurgical grade metal silicon powder into liquid chlorosilane such as trichlorosilane, and then remove the impurities in it by rectification and purification to obtain high-purity refined trichlorosilane. Chlorosilane, and then use high-purity hydrogen to reduce the purified high-purity refined trichlorosilane to polysilicon. [0003] The purity requirements of polysilicon products required by the photovoltaic industry are very high. The content of impurities such as phosphorus, boron and other metals in solar-grade polysilicon is required to be below 1ppb, and the impurity content of electronic-grade polysilic...

AI Technical Summary

Problems solved by technology

[0004] At present, domestic polysilicon factories generally adopt conventional multi-stage rectification technology to purify trichlorosilane. The number of rectification stages is large, and the height of the rectification tower is high, and the reflux ratio is large, so that the production of polysilicon consumes less heat and electricity. high

And the one-time investment cost is relatively high

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