Patent ID: 8303796

Claim:
A method for producing silicon by a molten salt electrolysis of silica in an electrolytic vessel with an electrolytic bath, comprising in order: a step (1) of using an alloy containing silicon in a liquid phase at an electrolysis temperature for a cathode and progressing the electrolysis to increase a content percentage of the silicon in the alloy; a step (2) of removing the alloy containing silicon in the cathode from the electrolysis vessel before the concentration of the silicon in the alloy becomes saturated at the electrolysis temperature; a step (3) of cooling the alloy containing silicon at temperatures higher than the eutectic point of the removed alloy containing silicon and lower than the electrolysis temperature to crystallize the silicon; a step (4) of collecting the solidified silicon, a step (5) of returning the alloy containing silicon in which the concentration of the silicon is reduced due to the collection of silicon at the step (4) to the cathode in the electrolytic vessel; and wherein the electrolysis temperature is higher than the eutectic point of the alloy containing silicon and lower than the melting point of silicon.