Revitalize the US silicon/ferrosilicon industry through energy-efficient technology. Part 1, Final report

It is concluded that silicon metal and ferrosilicon can be very effectively produced in a DC submerged arc furnace. Specific energy consumption factors measured were favorable to the technology. Significant energy savings over conventional AC practice are likely. Hollow electrode feeding of the furnace does not appear feasible. Electrode consumption was 0.144 lbs/lb so silicon while making metal, much of which occurred above the burden pile. Silicon loss to fume averaged 19.5% of the silicon charge. In this furnace, 50% FeSi was more difficult to produce than silicon metal, and the furnace could not be run with full burden; it was operated successfully about 3/4 full. In the silicon metal portion, the furnace was operated in a fully submerged mode for several 3-day test campaigns. The industry must seriously consider the identified benefits of DC plasma arc technology for retrofit or new added silicon capacity