Enhanced boron removal from metallurgical grade silicon by the slag refining method with the addition of tin

ABSTRACT

An effective boron removal method was developed through a process of combining Si–Sn alloy with slag treatment. Boron content in refined silicon and boron removal fraction by slag containing 5 wt% CaO, 25 wt% SiO₂ and 70 wt% Na₂SiO₃ and was investigated under varied Si–Sn alloy composition, slag/Si–Sn alloy mass ratio and refining time. Boron was effectively removed by adding tin to metallurgical grade silicon. In particular, the boron content in metallurgical grade silicon decreased from 12.92 ppmw to 0.79 ppmw by adding 50 at% tin under a mass ratio of 2:1 (slag:alloy) at 1723 K. The amount of boron removed increased with increasing amount of tin added, mass ratio and refining time.

KEYWORDS:

• Boron removal
• slag refining
• tin addition

Funding

This programme is financially supported by National Natural Science Funds of China (grant no. 51104028), National Natural Science Funds of China (grant no. 51574057) and the Fundamental Research Funds for the Central Universities (DUT15QY07).

Additional information

Funding

This programme is financially supported by National Natural Science Funds of China (grant no. 51104028), National Natural Science Funds of China (grant no. 51574057) and the Fundamental Research Funds for the Central Universities (DUT15QY07).