Boron removal from metallurgical-grade silicon using lithium containing slag

► Lithium containing refining slag for the removal of boron from silicon is proposed. ► Adding a small amount of Li2O or LiF has significant effect on LB. ► Mechanisms of boron removal using CaO-SiO2-Li2O and CaO-SiO2-LiF are discussed. ► w(B)inSi stops decreasing when the mass ratio of slag to silicon exceeds 4. ► w(B)inSi decreases with the increasing refining time.