System and method for preparing silane

Abstract

The invention discloses a system and a method for preparing silane by taking silicon powder and hydrogen as raw materials or trichlorosilane as a raw material. The system comprises a first disproportionation reaction rectifying tower, a tetrachlorosilane hydrogenation system, a second disproportionation reaction rectifying tower, a silane coarse distillation tower, a first silane rectifying towerand a second silane rectifying tower; the first disproportionation reaction rectifying tower is connected with the tetrachlorosilane hydrogenation system, and meanwhile, the first disproportionation reaction rectifying tower is connected with the second disproportionation reaction rectifying tower; the second disproportionation reaction rectifying tower is connected with the silane coarse distillation tower; the downstream of the silane coarse distillation tower is sequentially connected with the first silane rectifying tower and a second silane rectifying tower. Compared with the prior art, the method has the advantages that the chlorosilane conversion rate is high, the energy consumption is low, the cost is low, large-scale production is facilitated, the purity of obtained silane is 99.9999% or above and the electronic grade is reached, and the obtained silane can be used as a manufacturing material for large-scale integrated circuits, liquid crystal displays, photovoltaic cells andthe like.

Description

technical field [0001] The invention relates to the technical field of silane preparation, in particular to a system and method for preparing electronic-grade silane. Background technique [0002] At present, silane is widely used. The purity of 99.9% to 99.99% is called industrial grade silane, which is mainly used in the production of special glass in the glass industry, while the purity of more than 99.9999% is called electronic grade silane, which is mainly used for the preparation of extra large or very large scale integrated circuits. , chips, flat panel displays, amorphous silicon thin-film solar cells, high-purity polysilicon growth, preparation of silicon nitride, preparation of silicon carbide powder, etc. [0003] There are three main production processes for silane: silicon-magnesium alloy method, silicon tetrafluoride method, and chlorosilane disproportionation method. Among them, the silicon-magnesium alloy method has a simple process and adopts intermittent p...

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Problems solved by technology

Among them, the silicon-magnesium alloy method has a simple process and adopts intermittent production; however, its by-product magnesium chloride has high economic value, high energy consumption for sludge dehydration, large-scale production difficulty, large ammonia circulation, and high energy consumption

The silicon tetrafluoride reduction method can use sodium fluorosilicate as a by-product of chemical fertilizer enterprises, and can also use fluorite as a raw material. The by-product has high economic value, but consumes a large amount of high-priced raw material sodium and aluminum powder, resulting in high production costs. Generates a lot of energy consumption and the resulting silane has low purity

The process flow of the chlorosilane disproportionation method is very concise, adopts a closed-circuit system, the effective utilization rate of raw materials is high, the reactant and silane are easily separated, and high-purity silane can be obtained; however, the primary conversion rate of the disproportionation reaction is low, and the circulation of chlorosilane is large. Cause high energy consumption and high equipment investment

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