Removal of phosphorus from metallurgical grade silicon by Ar-H2O gas mixtures
(School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China)
Abstract: The removal of phosphorus in metallurgical grade silicon (MG-Si) by water vapor carried with high purity argon was examined. The effect of the nozzle types, refining time, refining temperature, refining gas temperature and refining gas flow rate on the phosphorus removed was investigated by the self-designed gas blowing device. The optimal refining conditions are nozzle type of holes at bottom and side, refining time of 3 h, refining temperature of 1793 K, refining gas temperature of 373 K, refining gas flow rate of 2 L/min. Under these optimal conditions, the phosphorus content in MG-Si is reduced from 94×10-6 initially to 11×10-6 (mass fraction), which indicates that gas blowing refining is very effective to remove phosphorus in MG-Si.
Key words: metallurgical grade silicon; gas blowing; phosphorus; thermodynamics