Precipitation Phase and Impurities Distribution of Metallurgical Grade Silicon by Vacuum Refining Followed Slag Treatment

Abstract:

Precipitation phase and impurities distribution of MG-silicon were investigated by vacuum refining followed by slag treatment, and the CaO-SiO₂-CaF₂ system was adopted for slag treatment. Contrasting the microstructure of precipitated phase in slag treatment with and without vacuum refining pretreated, it could be concluded that the composition of precipitated phases, obtained in MG-Si after vacuum refining followed slag treatment, only consisted of Ca-rich intermetallic silicide phases such as Si-Ca-Ni, Si-Ca-Fe and main impurity phase Si-Ca. And the vacuum refining could make an increase in concentration of the impurity Ti due to its low saturated vapor pressure and silicon loss, which was in favor of the interaction with the impurity B, resulting in the formation of TiB₂ that could stay at the slag. Consequently, the vacuum refining could be regarded as an effective method for facilitating the removal of B from MG-Si with slag treatment.

• Periodical: Advanced Materials Research (Volume 813)
• Pages: 492-496
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.813.492
• Online since: September 2013
• Authors: Hui Xian Lai, Liu Qing Huang, Ming Fang, Cheng Hao Lu, Juan Chen, De Qin Yu, Jin Tang Li, Wen Hui Ma, Jian Ning Shen, Xue Tao Luo
• Keywords: Impurities Distribution, Metallurgical Grade Silicon, Precipitation Phase, Slag Treatment, Vacuum Refining

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