A METHOD AND A REACTOR FOR PRODUCTION OF HIGH-PURITY SILICON

摘要

The present invention relates to a method and equipment for production of high purity silicon by reduction of SiCI₄ with molten Zn metal. The method is characterized in that the reduction takes place in contact with a molten salt that dissolves ZnCI₂. The ZnCI₂ produced during the reduction then dissolves in the molten salt rather than evaporates. The advantage is that gas evolution during the reduction is minimised, leading to higher utilisation of the SiCI₄ and Zn and thereby a higher Si yield. Another advantage is that the molten salt efficiently protects the air sensitive materials, Zn, SiCI₄ and Si, from oxidation during the reduction. The resulting molten salt containing the ZnCI₂ can be used for electrolysis of ZnCI₂ to regenerate the Zn metal. Chlorine evolved during the electrolysis can be used to produce SiCI₄.