Oxidation Kinetics and Mechanism of Boron in Metallurgical-Grade Silicon Melt by Oxidizing Refining

This research paper aims to optimize the purification process of industrial silicon oxygen blowing refining by exploring the reaction mechanism. The objective is to promote the widespread application and further development of photovoltaic technology. The article employs a combination of experimental analysis and ab initio molecular dynamics simulation calculations to investigate the oxidation mechanism for the removal of boron from metallurgical-grade silicon. The relationship between refining time and boron concentration in refined silicon was fitted to obtain the apparent rate constant and mass transfer coefficient of boron, which were determined to be 5.68 × 10−4 and 1.37 × 10−5 m s−1. Our experimental findings indicate a significant increase in the rate of silicon loss with prolonged refining time. Furthermore, our ab initio molecular dynamics simulation shows a strong interaction between B–O at higher temperatures, highlighting the effectiveness of oxygen blowing in boron removal. Using the Materials Studio software, the mean square displacement of impurity boron in silicon melt was calculated, yielding diffusion coefficients of 6.756 × 10−9 and 9.366 × 10−9 m2 s−1 at temperatures of 1723 K and 1823 K.