Improvement in Refinement of Metallurgical-Grade Silicon by Calcium Addition in Fractional Melting Process

Abstract

A new method was developed in this study to remove the liquid from a solid/liquid mixture in an induction heating applied system under the influence of centrifugal force. To segregate impurities and improve the refining ratio, calcium was added to the metallurgical-grade silicon. The behavior of impurities and the refining ratio were studied by scanning electron microscopy, electron probe microanalysis, and inductively coupled plasma mass spectroscopy. The impurities in Si were structurally arranged together and formed networks, which facilitated their removal during fractional melting. The refining ratio improved after the addition of Ca. Despite their high segregation coefficients, the concentrations of boron and phosphorus also reduced.