Method for melting refractory element in silicon metal by plasma flame gun bottom blowing

Abstract

The invention discloses a method used for fusing the elements difficult to be melted in metal silicon by bottom-blowing of a plasma frame gun, comprising the steps as follows: the flame outlet of the flame gun is arranged at the center of the bottom of a container used for storing silicon; the metal silicon is melted and poured into the container used for storing the silicon; subsequently, the plasma spark generated by the flame gun is pushed into the silicon liquid and turns over the silicon liquid; finally, the waste slag is removed. The method can richen the elements difficult to be melted in the metal silicon such as titanium, boron, carbon and the like on the surface of the silicon liquid, abandons the formed slag shell, and achieves the purification effect.

Description

technical field [0001] The present invention relates to the removal of refractory (high melting point) elements in metallic silicon, in particular to the removal of titanium (Ti, melting point 1725°C), boron (B, melting point 2300°C), carbon (C, melting point 3550°C) contained in metallic silicon ). Background technique [0002] In recent years, demand for silicon as a solar cell material has rapidly increased due to heightened concerns about energy / environmental issues such as the consumption of fossil fuel energy and global warming issues. With the rapid development of the photovoltaic industry, the growth rate of polysilicon demand for solar cells is higher than that of semiconductor polysilicon. In 1994, the total output of solar cells in the world was only 69MW, but in 2004 it was close to 1200MW, an increase of 17 times in just 10 years. Experts predict that the solar photovoltaic industry will surpass nuclear power to become one of the most important basic energy so...

AI Technical Summary

Problems solved by technology

However, during the purification process of metal silicon, its temperature is generally controlled at about 1600 ° C. The problem encountered in the purification process is some high melting point substances in metal silicon, such as titanium (Ti, melting point 1725 ° C), boron (B, melting point 2300 ° C) ℃), carbon (C, melting point 3550 ℃) cannot be melted, it is difficult to discharge and discard, so that the purpose of purification cannot be achieved

Moreover, the above method can only remove one of the main impurities, but cannot remove titanium, boron, and carbon in metal silicon at the same time.