Abstract: What is described is a process for the production of silicon via the carbothermic reduction of silicon dioxide in which silicon carbide is fed as the total reductant source or as a portion of the reductant input. The process also includes recovery and recycle to the furnace silicon monoxide and other silicon-containing materials from the by-produced gases from the furnace to maximize raw material efficiency. Finally, the process includes the recovery of value from the by-produced gases via the use of the gases as a chemical intermediate or the use of the gases as a fuel for a combustion process.

Abstract: What is disclosed is a process for preparing silicon using a gas plasma as a heat source. The process comprises (a) generating a gas plasma in a reactor utilizing a transferred arc plasma configuration in which a minimum of gas is utilized to form a plasma; (b) feeding silicon dioxide and a solid reducing agent directly into the reactor and to the plasma; (c) passing the plasma gas, the silicon dioxide, and the solid reducing agent into a reaction zone of the reactor; (d) recovering molten silicon and the gaseous by-products.

Abstract: There is described a method of closing ends of silicon tubular bodies in which the tube end to be closed is dipped into melt of silicon maintained at substantially the melting temperature of silicon until the end of the tube is heated to the melting point and then withdrawing the tube from the melt with melt temperature sufficiently low to cause freezing of molten silicon at tube end and at temperature and speed sufficient to cause decreasing diameter of the freezing silicon until the desired diameter reduction or closure is obtained and then breaking contact with the melt. Additionally, surface portions may be machined after withdrawal from the melt to allow connections to be made.