Effect of pellet size and additive on silica carbothermic reduction in microwave furnace for solar grade silicon

Silicon as a raw material for solar cells can be produced by numerous methods. The carbothermic reduction of silica using electric arc furnace is the most widely used process in silicon industry. This paper presents a new approach to produce solar grade silicon using microwave furnace. Pellets of different sizes were prepared from a mixture of silica and carbon using water and polyvinyl alcohol as binder agents. Raman spectra indicated a peak at about 515 cm⁻¹ attributed to silicon in the pellets prepared with polyvinyl alcohol, and peaks at about 523 cm⁻¹ and 794 cm⁻¹ attributed to silicon and silicon carbide, in the pellets prepared with water. The pellet size affects the absorption of microwave energy emitted from the magnetrons. Polyvinyl alcohol as a binder agent is promising for the production of silicon using microwave furnace.