摘要:
Metal Sm has been widely used in making Al-Sm magnet alloy materials. Conventional distillation technology to produce Sm has the disadvantages of low productivity, high costs, and pollution generation. The objective of this study was to develop a molten salt electrolyte system to produce Al-Sm alloy directly, with focus on the electrical conductivity and optimal operating conditions to minimize the energy consumption. The continuously varying cell constant (CVCC) technique was used to measure the conductivity for the Na
3AlF
6-AlF
3-LiF-MgF
2-Al
2O
3-Sm
2O
3 electrolysis medium in the temperature range from 905 to 1055℃. The temperature (
t) and the addition of Al
2O
3 (
W(Al
2O
3)), Sm
2O
3 (
W(Sm
2O
3)), and a combination of Al
2O
3 and Sm
2O
3 into the basic fluoride system were examined with respect to their effects on the conductivity (κ) and activation energy. The experimental results showed that the molten electrolyte conductivity increases with increasing temperature (t) and decreases with the addition of Al
2O
3 or Sm
2O
3 or both. We concluded that the optimal operation conditions for Al-Sm intermediate alloy production in the Na
3AlF
6-AlF
3-LiF-MgF
2-Al
2O
3-Sm
2O
3 system are W(Al
2O
3) + W(Sm
2O
3)=3wt%, W(Al
2O
3):W(Sm
2O
3)=7:3, and a temperature of 965 to 995℃, which results in satisfactory conductivity, low fluoride evaporation losses, and low energy consumption.