【摘要】 运用分子相互作用体积模型预测了二元硅基熔体中Zn、Sb、Mg、Mn、Cu和Sn的活度系数.结合模型所得的对势能相互作用B参数和活度等热力学数据,计算了硅与各杂质元素形成的二元系蒸发系数和挥发速率,绘制出了硅基合金蒸馏过程中的气液相平衡图。研究结果表明,模型所预测的活度值与实验值吻合很好,真空精炼有利于Sb、Zn、Mg从硅熔体中分离,而Mn、Cu、Sn难以分离。硅中的各杂质的蒸发行为受其活度和温度的联合控制。本文通过对冶金硅中杂质挥发性质的研究,为真空提纯冶金级硅提供了可靠的理论依据。更多还原

【Abstract】 The volatilization of the impurities( Zn,Sb,Mg,Mn,Cu and Sn),in binary Si-based solutions in vacuum refining of metallurgical grade Si,was mathematically formulated with molecular interaction volume model( MIVM),theoretically analyzed in thermodynamics and experimentally investigated. The separation coefficient,volatilization rate and gas-liquid equilibrium diagram of silicon-based binary alloy in vacuum distillation of Si were derived in terms of the pair interaction potential B and activities calculated with MIVM model. The calculated results show that the evaporation of impurity significantly depends on the distillation temperature and its activity. After most Sb,Zn and Mg impurities were removed from the molten silicon,the contents of Mn,Cu and Sn decreased but slowly because of the low evaporation rates. The measured and predicted results were found to be in good agreement. We suggest that the calculation be of some basic interest in vacuum refining of metallurgical grade silicon.更多还原