Phosphorus Removal from Metallurgical-Grade Silicon by Vacuum Arc Refining

Phosphorus is very difficult to remove during the purifying of metallurgical-grade silicon by metallurgical method.In this paper,phosphorus evaporation removal by vacuum arc furnace with electromagnetic stirring was investigated in vacuum weak oxidation atmosphere.The effects of refining time,electromagnetic stirring treatment and initial phosphorus content on the removal behavior of phosphorus in metallurgical-grade silicon were studied in detial. The result shows that the reduction of phosphorus using vacuum arc refining method was very obvious,especially in the first 10 minutes,and the removal rate of phosphorus increased with the refining time.Electromagnetic stirring is also benefit to the removal of phosphorus evaporation,which can be attributed to the improved mobility of phosphorus element from the internal to the surface(i.e.,improved kinetics condition)of melt.It was also observed that high purity sample could be obtained in the initial materials with low phosphorus content.