POLYCRYSTALLINE SILICON PROCESS Russian patent published in 2009 - IPC C01B33/03 C01B33/35 

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical and electronic industry. Polycrystalline silicon is produced by hydrogen reduction of silicone rod trichlorosilane. Exhaust gas-vapour mixture is condensed with hydrogen recirculation following absorption treating. Condensation involves grading as containing trichlorosilane delivered to the process top. Distillation residue containing polysilane chlorides 5 - 10% and 90 - 95% silicon tetrachloride is delivered to hydrogenation in a hydrogenation reactor to produce trichlorosilane reduced to silicon with increasing process temperature to 1100 - 1200°C and specified molar ratio of hydrogen to chlorosilanes as (6-12):1. The prepared exhaust gas-vapour mixture is cooled to produce silicon tetrachloride and trichlorosilane thereafter delivered back to the silicone process stage.

EFFECT: cost reduction of polycrystalline silicon process due to trichlorosilane generation in hydrogenation of waste silicon tetrachloride and polysilane chlorides.

3 cl, 1 dwg