| 摘要 |
<p>Disclosed is a method for purifying silicon, which comprises the steps as follows: molten Na2CO3 is added into molten silicon to be purified in an amount of 10% by weight of silicon to be purified, and after stirring for 10 minutes, a covering agent is placed on the surface of the mixture melt, which is then sealed; the temperature of silicon to be purified is monitored and recorded therefrom; the cooling rate is decreased when the temperature is lowered to 1490-1510?; the heating power is kept constant when the temperature is lowered to the melting point of silicon; heating is stopped when silicon begins to cool down; silicon in the solid state is removed after cooling down to the room temperature naturally; after the silicon being crushed at room temperature, a mixed acid solution is added and then is subjected to standing for 12 hours in a fume hood; silicon grains fragmented by leaching are separated from the acid solution and then are soaked upon adding water thereto, which are rinsed with water to neutrality and filtered and dried to give silicon product with high purity. As compared with traditional directional solidification and zone melting, the segregating efficiency of impurities in the solidification is improved substantially, the purification process is shortened greatly, and the actual yield of the pure material is increased.</p> |
