| Abstract: | The global shortage of solar grade silicon for production of solar cells has motivated a lot of research on the refining of metallurgical grade silicon. However, approaches to upgrade metallurgical grade silicon have been mainly handicapped by difficulties in reducing boron and phosphorus levels. In the present study, the possibility of refining metallurgical grade silicon to remove impurity boron using Na2O-CaO-SiO2 slags was investigated. Before slag melting, a process of mixing pulverized slags and silicon under an action of mechanical force was used to provide a higher probability of contact and reaction of slags and silicon. The melting time was reduced with an increase in contact area A S , resulting in improved efficiency of boron removal. The parameters, including the slag basicity, and the weight ratio of silicon to slag were discussed. The process of slag treatment was performed twice and directional solidification was conducted to promote the separation of slags from silicon. A maximum value of L B (5.81) was obtained when the basicity was 1.21, and the weight ratio of silicon to slag was 5. |
