Abstract The mass transfer behavior of vapor silicon (Si) and volatile impurities during refining of Si by electron beam melting is still unclear. In present work, with gas flow guidance, the mass transfer mechanism of vapor Si and volatile impurities, and corresponding heat transfer rule in the furnace chamber are investigated by simulation and experiment. Numerical simulation shows that vapor Si is preferentially transferred to the outlet, and temperature in the outlet is lower than the solidification temperature of vapor Si when gas flow is fixed at 0° and 1.16 m s−1 (optimal conditions). Experimental results show that volatile impurities are effectively removed (P and Al both are less than 0.01 ppmw in the refined Si ingot with >99% of removal efficiency). Moreover, volatile impurities flux positively increases with increase of vapor Si flux. Gas flow significantly gathers the vapor Si in the outlet, reinforcing evaporation kinetics of molten Si and volatile impurities, which demonstrates the numerical simulation model is feasible to control the mass transfer and evaporation kinetics. Gas flow guidance may be a promising way to improve volatile impurities removal from Si.

中文翻译：

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硅精炼过程中用气流引导控制气相硅和挥发性杂质传质的模拟模型

摘要 蒸汽硅（Si）和挥发性杂质在电子束熔炼精炼过程中的传质行为尚不清楚。在目前的工作中，通过气体流动引导，通过模拟和实验研究了蒸汽Si和挥发性杂质的传质机理，以及相应的炉膛传热规律。数值模拟表明，当气流固定在0°和1.16 m s-1（最佳条件）时，蒸汽Si优先转移到出口，出口温度低于蒸汽Si的凝固温度。实验结果表明，挥发性杂质被有效去除（精制硅锭中P和Al均小于0.01 ppmw，去除效率> 99％）。而且，挥发性杂质通量随着蒸汽Si通量的增加而正增加。气流在出口处明显聚集了蒸汽Si，加强了熔融Si和挥发性杂质的蒸发动力学，这表明数值模拟模型在控制传质和蒸发动力学方面是可行的。气流引导可能是一种改善从 Si 中去除挥发性杂质的有前途的方法。