Boron separation from Si–Sn alloy by slag treatment
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This study investigates a purification process for metallurgical-grade silicon (MG-Si) in which Si is alloyed with tin (Sn) and CaO–SiO2–CaCl2 slag is used to remove boron (B) impurity. Acid leaching was performed to remove the Sn phase after slag refining to recover high-purity Si from the Si–Sn alloy. The effect of refining time was investigated, and acceptable refining results were realized within 15 min. The effects of slag composition and Sn content on the removal of B were also studied. The results indicate that increasing Sn content favors B removal. With the increase of Sn to 50% of the alloy, the final B content decreased to 1.1 × 10−4wt%, 93.9% removal efficiency.
Keywordsboron removal metallurgical grade silicon Si–Sn alloy slag refining
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This work was financially supported by the National Natural Science Foundation of China (Grant Nos. 51334002 and 51604023), Beijing Key Laboratory of Green Recycling and Extraction of Metals (GREM), the Laboratory of Green Process Metallurgy and Modeling (GPM2) and the High Quality steel Consortium (HQSC) at the School of Metallurgical and Ecological Engineering at University of Science and Technology Beijing (USTB), the Chinese government scholarship information System C.S.C, China.
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