电子束熔炼冶金级硅中杂质钙的蒸发行为

Evaporation behavior of calcium in metallurgical silicon by an electron beam melting method

通过双枪电子束熔炼炉熔炼冶金级硅,主要研究了在一定熔炼功率不同熔炼时间下,杂质Ca含量的变化及其蒸发行为,讨论了杂质Ca含量与Si剩余率的关系。实验结果表明,熔炼初期杂质Ca含量显著降低,随着熔炼时间的延长,下降趋势逐渐减缓。在硅熔体表面2133K温度下,杂质Ca的自由蒸发反应遵循一级反应速率方程。杂质Ca的总传质系数为2.64×10-5m/s,并且杂质Ca从熔体内部迁移到硅熔体/气相界面层是其蒸发过程的速率控制步骤。

In order to investigate Ca evaporation behavior in the electron beam melting process,metallurgical-grade silicon was melted in an electron beam furnace with electron beam power kept constant while the melting time changed.And the relationship between yield of Si and Ca content was discussed.The results showed that the content of impurity Ca was significantly decreased in the early period of melting,and then changed slowly with the extension of the melting.The free evaporation of Ca at 2133K,the calculated surface temperature of the liguid silicon,followed first order kinetics.The overall mass transfer coefficient of Ca was determined to be 2.64×10-5m/s,and the removal rate of Ca was controlled by the transfer of Ca atoms from the bulk liquid silicon to liquid/gas phase interface.