Experimental study on hot melt splashes during electromagnetic continuous casting silicon

Hot melt splashes often take place during electromagnetic casting silicon, which break the stable pulling process and endanger the safety of equipments in the vacuum chamber. Investigations are carried out to analyze the causes of melt splashes and put forward measures to prevent the happening of them. Pores with different sizes are observed in perpendicular sections of the left ingots, their surface compositions are analyzed by EDS. The results indicate that they are rich in O, Al, Ca and Mg elements, which means that the driving pressures of hot melt splashes are mainly the vapor tension of SiO, Al, Ca and Mg. Calculated results show that the volatilization of those elements is inevitable, so the vapor excluding and pressure releasing are key issues for preventing hot melt splashes, both of which are affected by the height and top position of the liquid dome. Therefore, controlling of those parameters properly can efficiently prevent the hot melt splashes. The optimal dome top position is from 6 mm to 16 mm lower than the coil top position.

► Hot melt splashes is caused by the instantaneously releasing of vapor pressure of the bubbles.
► The volatilization and the silicon oxidation are inevitable.
► All pores surface and volatiles are rich in O, Al, Ca, Mg.
► The ideal dome top position is from 6 mm to 16 mm lower than the coil top position.