Boron removal from metallurgical-grade silicon by CaO–SiO2 slag refining
来源期刊：Rare Metals2015年第7期
论文作者：Kui-Xian Wei Hai-Fei Lu Wen-Hui Ma Yan-Long Li Zhao Ding Ji-Jun Wu Yong-Nian Dai
文章页码：522 - 526
摘 要：Boron removal from metallurgical-grade silicon（MG-Si） using CaO–SiO2 slag was studied by employing a medium-frequency electromagnetic induction furnace.The relationship between the optical basicity（K）of the CaO–SiO2 slag and the distribution coefficient of boron（LB） was investigated.Consequently, the local minimum and maximum LBvalues of 0.72 and 1.58 are obtained when K = 0.56 and K = 0.71, respectively.The boron content in MG-Si decreases gradually with refinement time increasing, down to a minimum value of4.73 9 10-6.The controlling step in the removal of boron from MG-Si is not the chemical reaction at the interface of the slag and silicon.Instead, the controlling step is a diffusion mass transfer, in which boron impurities diffuse from molten silicon to the interface of the slag and silicon,or B2O3 formed by the chemical reaction diffuses from the slag–silicon interface to molten slag.
Kui-Xian Wei1，Hai-Fei Lu1，Wen-Hui Ma1,2，Yan-Long Li1，Zhao Ding2，Ji-Jun Wu1，Yong-Nian Dai1,2
1. The National Engineering Laboratory for Vacuum Metallurgy and State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology2. Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province and Engineering Research Center for Silicon Metallurgy and Silicon Materials of Yunnan Provincial Universities, Kunming University of Science and Technology
摘 要：Boron removal from metallurgical-grade silicon（MG-Si） using CaO–SiO2 slag was studied by employing a medium-frequency electromagnetic induction furnace.The relationship between the optical basicity（K）of the CaO–SiO2 slag and the distribution coefficient of boron（LB） was investigated.Consequently, the local minimum and maximum LBvalues of 0.72 and 1.58 are obtained when K = 0.56 and K = 0.71, respectively.The boron content in MG-Si decreases gradually with refinement time increasing, down to a minimum value of4.73 9 10-6.The controlling step in the removal of boron from MG-Si is not the chemical reaction at the interface of the slag and silicon.Instead, the controlling step is a diffusion mass transfer, in which boron impurities diffuse from molten silicon to the interface of the slag and silicon,or B2O3 formed by the chemical reaction diffuses from the slag–silicon interface to molten slag.
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