A process for producing high purity silicon characterized by the employment of an electric arc heater into which a silicon halide is injected together with a metal reductant such as an alkali metal or an alkaline-earth metal which are reacted together by projecting them tangentially into a reaction chamber...http://www.google.com/patents/US4102765?utm_source=gb-gplus-sharePatent US4102765 - Arc heater production of silicon involving alkali or alkaline-earth metals
