Patent ID: 8778143

Claim:
A method for purifying silicon using a silicon, purification device having at least a crucible for loading a silicon metal and a plurality of plasma torches, the method including: purifying the silicon metal by injecting a plasma gas from the plasma torches toward a melt surface of the silicon metal loaded in the crucible in a state where an angle formed by the melt surface and the plasma gas is set to be in the range of 20° to 80°; spraying the plasma gas from the plasma torches so as to form a plurality of recesses on the melt surface; causing a circulation flow of the melt surface; spraying the plasma gases from the respective plasma torches in a tangential direction of a virtual circle A having the recesses on a circumference of the virtual circle A in a manner such that the plasma gases are aligned in one direction of the circumference of the virtual circle A; and spraying the plasma gases so as to satisfy the following equation (1), where l is a radius of the virtual circle A, L is a radius of a virtual circle B having a center same as the virtual circle A and inscribed in an outer circumference of the melt surface, and i is a diameter of the recesses in a direction perpendicular to a tangent line of the virtual circle A 3 i≦l≦L− 3 i. (1)