METHOD OF PRODUCING POLYCRYSTALLINE SILICON IN CLOSED CIRCUIT

摘要

FIELD: silicon production. SUBSTANCE: method includes hydrogen reduction of trichlorosilane, separating and purifying components of gas mixture (SiHCl3,SiCl4,H2,HCl) leaving reactor, reusing these components to prepare polycrystalline silicon and carrying out trichlorosilane synthesis. According to invention, gas mixture of trichlorosilane reduction products is cooled to temperature from 0 to 40 C, filtered to remove solid impurities, and condensed at liquid nitrogen temperature to separate recycled hydrogen. Hydrochloric acid is sublimed at 85 C and then evaporated. Chlorosilanes are separated, and trichlorosilane is directed into hydrogen reduction apparatus. Silicon tetrachloride together with hydrogen chloride are directed into trichlorosilane synthesis apparatus, where industrial-grade silicon is also used. EFFECT: enabled closed-circuit conditions and improved product quality.