Abstract: A method for purifying silicon includes placing silicon to be purified and an aluminum-silicon alloy ingot, made from high purity aluminum in close contact in a closed environment to be subjected to heating under vacuum, such that the aluminum-silicon alloy ingot is melted into an aluminum-silicon melt. The temperatures are kept constant when the temperature M the interface of the silicon and the aluminum-silicon melt and the temperature at a free end of the aluminum-silicon melt reach 900° C. and 800° C. respectively. As the purified silicon begins to segregate and the interface, the heating apparatus is moved in step with the growth rate of the segregated silicon toward the silicon to be purified to maintain the temperatures at both ends of the aluminum-silicon melt. The segregated pure silicon is cut off upon the completion of dissolution of purified silicon and after cooling and air pressure recovery.

Abstract: A method for purifying silicon includes adding molten Na2CO3 to molten silicon to be purified in an amount of 10% by weight of silicon. After stirring for 10 minutes, a covering agent is placed on the surface of the mixture melt and sealed. The cooling rate of the silicon is decreased when the temperature is lowered to 1490-1510° C. Heating power is kept constant while the temperature is lowered to the melting point of silicon. Heating is stopped when silicon begins to cool down below the melting point, and solid state silicon is removed after reaching room temperature. The silicon is crushed at room temperature. A mixed acid solution is added and maintained for 12 hours in a fume hood. Silicon grains fragmented by leaching are separated from the acid solution and soaked upon adding water thereto, which are rinsed with water to neutrality and filtered and dried, yielding silicon with high purity.