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...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.展开更多
This study investigates a purification process for metallurgical-grade silicon(MG-Si) in which Si is alloyed with tin(Sn) and Ca O–Si O_2–Ca Cl_2 slag is used to remove boron(B) impurity. Acid leaching was performed...This study investigates a purification process for metallurgical-grade silicon(MG-Si) in which Si is alloyed with tin(Sn) and Ca O–Si O_2–Ca Cl_2 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^(-4) wt%, 93.9% removal efficiency.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51461027 and 51104080)
文摘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.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 51334002 and 51604023)
文摘This study investigates a purification process for metallurgical-grade silicon(MG-Si) in which Si is alloyed with tin(Sn) and Ca O–Si O_2–Ca Cl_2 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^(-4) wt%, 93.9% removal efficiency.
