Electrical conductivity optimization of the Na3AlF6–Al2O3–Sm2O3 molten salts system for Al–Sm intermediate binary alloy production

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 Na3AlF6–AlF3–LiF–MgF2–Al2O3–Sm2O3electrolysis medium in the temperature range from 905 to 1055°C. The temperature(t) and the addition of Al2O3(W(Al2O3)), Sm2O3(W(Sm2O3)), and a combination of Al2O3and Sm2O3into 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 Al2O3or Sm2O3or both. We concluded that the optimal operation conditions for Al–Sm intermediate alloy production in the Na3AlF6–AlF3–LiF–MgF2–Al2O3–Sm2O3system are W(Al2O3) + W(Sm2O3) = 3wt%, W(Al2O3):W(Sm2O3) = 7:3, and a temperature of 965 to 995°C, which results in satisfactory conductivity, low fluoride evaporation losses, and low energy consumption.

Electrical conductivity of molten LiF–DyF3–Dy2O3–Cu2O system for Dy–Cu intermediate alloy production

Dy–Cu intermediate alloys have shown substantial potential in the field of magnetostrictive and magnetic refrigerant materials.Therefore,this study focused on investigating the electrical conductivity of molten-salt systems for the preparation of Dy–Cu alloys and on optimizing the corresponding operating parameters.The electrical conductivity of molten LiF–DyF3–Dy2O3–Cu2O systems was measured from 910 to 1030°C using the continuously varying cell constant method.The dependencies of the LiF–DyF3–Dy2O3–Cu2O system conductivity on the melt composition and temperature were examined herein.The optimal operating conditions for Dy–Cu alloy production were determined via analyses of the electrical conductivity and activation energies for conductance,which were calculated using the Arrhenius equation.The conductivity of the molten system regularly increases with increasing temperature and decreases with increasing concentration of Dy2O3 or Cu2O or both.The activation energy Eκof the LiF–DyF3–Dy2O3 and LiF–DyF3–Cu2O molten-salt systems increases with increasing Dy2O3 or Cu2O content.The regression functions of conductance as a function of temperature(t)and the addition of Dy2O3(W(Dy2O3))and Cu2O(W(Cu2O))can be expressed asκ=-2.08435+0.0068t-0.18929W(Dy2O3)-0.07918W(Cu2O).The optimal electrolysis conditions for preparing the Dy–Cu alloy in LiF–DyF3–Dy2O3–Cu2O molten salt are determined to be 2.0wt%≤W(Dy2O3)+W(Cu2O)≤3.0wt%and W(Dy2O3):W(Cu2O)=1:2 at 970 to 1000°C.

Erratum to: Electrical conductivity of molten LiF–DyF3–Dy2O3–Cu2O system for Dy–Cu intermediate alloy production

Erratum to:International Journal of Minerals, Metallurgy and Materials Volume 26, Number 6, June 2019, Page 701https://doi.org/10.1007/s12613-019-1775-z The acknowledgements of this article unfortunately contained a mistake. The grant number of the National Natural