International Journal of Energy for a Clean Environment 14(2–3), 183–189 (2013) 2150-3621/13/$35.00 © 2013 by Begell House, Inc. 183 I. INTRODUCTION Photovoltaic transforming of solar energy into electricity with solar cells is now regarded as one of the promising methods of electric power. Environmental friend- liness of inexhaustible source of energy and the energy of sunlight promote for this trend. DEVELOPMENT OF TECHNOLOGICAL FOUNDATIONS FOR PURE SILICON PRODUCTION BY CARBOTHERMIC REDUCTION B. Bondarenko, V. Bogomolov, A. Kozhan, A. Khovavko, * V. Nazarenko, & K. Simeyko Gas Institute, National Academy of Sciences, 39 Degtyarivska St., 03113 Kiev, Ukraine * Address all correspondence to A. Khovavko E-mail: ahova2005@ukr.net Currently, pure silicon suitable for use in photovoltaics is produced by the expensive Siemens chloride method. Nevertheless, efforts are continuing to manufacture clean and suitable silicon for photovoltaics by the metallurgical method of carbothermic reduction. In the availability of pure silica materials, the main obstacle in an implementation of this technology is the lack of sufficiently pure carbon reductants. We proposed to use pyrocarbon as a reducing agent. This py- rocarbon is formed as an encapsulation coating of granular quartz particles with their treatment by gaseous hydrocarbons in electrothermal fluidized bed. The thickness of the resulting layer of pure pyrocarbon can be regulated within prescribed limits by temperature, hydrodynamics, and process duration. We constructed the laboratory and pilot plants for production of raw materials in large quantities on the basis of granular quartz capsulated by pyrocarbon for the subsequent electromelting. Atempts to melt the referred charge in an usual induction furnace and an elec- tron-beam furnace have not brought the desired result because of a number of technical and phys- ical reasons. Afer a theoretical analysis and discussions with experts, the new ion-plasma unit for reduction melting has been created. The process has been carried out in an argon atmosphere, at an operating pressure of 0.0001–0.001 torr. The first experimental meltings showed positive results. Melting in a diffuse arc discharge in vacuum allows to refine metallurgical silicon by evaporation and oxidation of impurities. KEY WORDS: pure silicon, pyrocarbon, electrothermal fluidized bed, reduction, melting