钾冰晶石—氧化钪体系中铝热还原反应过程的研究

在钾冰晶石—氧化钪熔盐中,采用铝热还原和直接电解制备铝钪合金。在引入Al3Sc相生成自由能并考虑活度后,热力学计算表明,铝热还原氧化钪反应在本试验条件下可以发生。750℃在K3AlF6-2%Sc2O3(CR=1.22)熔盐中,电解制备的合金中钪含量可达0.97%,而铝热还原反应所获合金中钪含量小于0.18%,且随反应时间的延长和熔盐中氧化钪浓度的增加,合金钪含量的增幅趋缓。电解合金中钪分布均匀,而铝热还原合金中钪主要存在于边缘区域。

Study on Aluminum Thermo-Reduction in K3AlF6-Sc2O3 System

Al-Sc alloy was prepared in K3AlF6-Sc2O3 melt system by aluminum thermo-reduction and electrolysis process respectively.Thermodynamic analysis shows that Sc2O3 can be reduced by aluminum when Al3Sc phase is included with an introduction of free energy and activity.The results show scandium content of the alloy from electrolysis process reaches 0.97% at 750 ℃ in K3AlF6-2%Sc2O3(CR=1.22) melt system,while that of the alloy from aluminum thermo-reduction may be limited to 0.18%.Scandium content changes little with an increase of Sc2O3 concentration in the melt and prolonged reaction time.Scandium is better distributed in electrolysis-made alloy than that in thermo-reduction.Scandium mainly exists in the edge area of alloy samples.