Method for preparing trichlorosilane

Abstract

The invention relates to a method for preparing trichlorosilane. The method comprises the step that silicon tetrachloride and hydrogen react with optional hydrogen chloride and silicon powder by adopting at least one main catalyst selected from copper halide and nickel halide and at least one auxiliary catalyst selected from alkali metal compounds. Compared with the prior art, the method for preparing the trichlorosilane has the advantages of low preparing cost, simple and easy technique and high per-pass conversion rate of the silicon tetrachloride.

Description

technical field [0001] The invention relates to a method for producing trichlorosilane, in particular to a method for producing trichlorosilane through catalytic hydrogenation of silicon tetrachloride. Background technique [0002] Polysilicon is the raw material of solar photovoltaic modules. With the introduction of favorable policies for the photovoltaic industry, the photovoltaic industry will surely set off an upsurge, and the market demand for polysilicon will inevitably increase accordingly. [0003] At present, more than 70% of polysilicon manufacturing technologies in the world use the improved Siemens method. The modified Siemens method to manufacture polysilicon is mainly obtained by depositing trichlorosilane and hydrogen on the surface of the silicon core at high temperature in a reduction furnace. While polysilicon is produced, a large amount of silicon tetrachloride is by-produced. On average, 15-20 tons of trichlorosilane will be consumed for every 1 ton of ...

AI Technical Summary

Problems solved by technology

Silicon tetrachloride easily reacts with water to form silicon dioxide and hydrogen chloride, and direct discharge will seriously affect the ecological environment

This technology must be supplemented with a gas separation device to separate the reaction product and process hydrogen chloride, so it requires a large investment and occupies a large area

In addition, thermal hydrogenation technology also has the following disadvantages: high reaction temperature, complicated process, and difficult device operation; the heater uses carbon-carbon composite materials, which can only be imported, and the cost is high; the requirement for raw material purity is high, which cannot be solved By-product dichlorosilane in the polysilicon manufacturing process; low conversion rate and high energy consumption, with an average power consumption of 3200-3500kwh per 1t of trichlorosilane produced

[0013] 1. The catalyst used in the manufacture of trichlorosilane contains noble metal components, so the cost of the catalyst is relatively high, resulting in a relatively high manufacturing cost of trichlorosilane;

[0014] 2. When producing trichlorosilane according to the thermal hydrogenation method, due to the high reaction temperature, the production operation difficulty and production cost are relatively high;

[0016] 4. Regardless of whether trichlorosilane is produced by thermal hydrogenation or cold hydrogenation, the single-pass conversion rate from silicon tetrachloride to trichlorosilane is low, generally only 17-25%, and there is still a large Room for improvement

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