Production of silicon by microwave heating

Abstract

Mixed powder of SiO₂ and SiC was heated to produce Si in air by irradiating multi-mode microwave at 2.45 GHz using a porous alumina crucible of sintered cement. SiC generated heat inside the mixture. Mullite layer was produced inside of crucible wall. Molten Si was produced at the apparent temperature between 1550°C and 1600°C during 5400s and 6000s. The apparent temperature was much lower than 1778°C determined thermodynamically. This is the characteristics of microwave that heat generates at the contact points of particles and the pointed parts of the surface in powder. A furnace for producing high-quality Si by microwave heating is proposed.