PROCESS FOR THE PREPARATION OF SILICON FROM THE REDUCTION OF SILICON DIOXIDE WITH A SOLID CARBONACEOUS REDUCING AGENT, AND PROCESS FOR THE PREPARATION OF SILICON CARBONIDE FROM THE SILICON DIOXIDE REACTION AND SOLID CARBONACEOUS REDUCING AGENT

摘要

What is described is an improvement to a process for the preparation of silicon from the reduction of silicon dioxide with a solid carbonaceous reducing agent, the improvement comprising feeding calcium compounds into the reaction zone of a silicon furnace, and controlling and maintaining a desired calcium level in the reaction zone of the silicon furnace. The calcium compounds may be fed to the silicon furnace as a constituent of either the silicon dioxide or solid carbonaceous reducing agent feeds, as a separate feed, or as a combination of two or more of these feeds. Also described is an improvement to a process for the preparation of silicon carbide from the reduction of silicon dioxide with a solid carbonaceous reducing agent.