METHOD FOR PRODUCING SILICON, METHOD FOR SEPARATING SILICON FROM MOLTEN SALT AND METHOD FOR PRODUCING TETRAFLUORIDE

摘要

The invention relates to semiconductor silicon technology. The inventive method consists in electolytically decomposing a silicon tetrafluoride-saturated eutectic melt of a ternary system of alkali metal fluoride salts. For saturating the melt, a silicon tetrafluoride obtainable by fluorinating a silicon dioxide is used, wherein said fluorination is carried out in two stages, i.e. at a first stage, an elemental fluorine is supplied with excess and a silicon dioxide is supplied at the second stage. The silicon powder separation from the fluoride salt eutectic melt is carried out by dissolving the silicon particles-containing melt with the aid of anhydrous hydrogen fluoride and by subsequently filtering for isolating a solid phase in the form of a silicon powder.