Low Cost Silicon Solar Array Project, Silicon Materials Task. Development of a Process for High Capacity Arc Heater Production of Silicon for Solar Arrays. Quarterly Technical Report, July--September 1977

摘要

Major emphasis was focused on obtaining price data for the various system components required for a plant that produces 1000 MT/year of silicon based on a recycle scheme. This data will serve as the basis for the economic analysis for 1000 MT of silicon per year production. Work continued on the system purity analysis which will predict the maximum allowable impurities in the feedstocks (SiCl sub 4 and sodium) based on a desired purity of the silicon product. The computer program, CHEMEQ, has been modified for this purity analysis. Also, the activity coefficients of Fe, Cr, Mn, and Al in liquid silicon at several temperatures have been obtained. These are the metallic impurities in silicon that are being considered for the purity analysis along with Ti and V. Estimation of values for the activity coefficients for Ti and V in liquid silicon is still in progress. System components and cost information have been assembled for the SiCl sub 4 feed system, sodium feed system, plasma reactor/separator system, and the silicon collection system. This data is being factored into the capital equipment costs for the economic analysis for the 1000 MT of Si/year case. Effort was continued to specify and assemble cost information for the NaCl electrolysis system that is necessary for the recycle process envisioned to produce 1000 MT of silicon/year. (ERA citation 03:044357)