Facile Electrochemical Preparation of Al-Sm Alloys in Molten Calcium Chloride

Abstract

The direct preparation of metallic Sm or alloys from raw oxide Sm 2 O 3 is an attracting but challenging process. The stable electrochemical behavior and low solubility of Sm 2 O 3 limit the extraction of Sm element in molten salts. Here, it is found that metallic Sm is hardly obtained by electro-deoxidation and aluminothermic reduction of solid Sm 2 O 3 pellet according to experiment and calculation. Through the novel electrochemical reduction of solid Sm 2 O 3 -Al pellet, Al 3 Sm alloy with ∼0.4 Sm/Al molar ratio is successfully prepared in calcium chloride melt at 1173 K. The reduction potential of Sm 2 O 3 -Al pellet to Al-Sm alloy is more positive than that of calcium. Al plays an indispensable role in the reduction of Sm 2 O 3 . The preparation process of alloy can be well identified as two steps: Sm(III) → Sm(II) and Sm(II) → Sm(0). Sm 2 O 3 is firstly converted to Sm(II) based on the combination of electrochemical and aluminothermic reduction. Then, Al 3 Sm is formed by electrochemical reduction and alloying with Al.

Electrochemical Behavior of SmF3 in Alkali Chloride Melts

“…15,19,[21][22][23] The electrochemistry of lanthanides in various molten salts has been investigated in many studies. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] Electrochemical behavior of SmF 3 in LiF-BeF 2 on an inert molybdenum electrode was investigated. 27 The two steps-reduction mechanism of samarium was identified in molten eutectic LiF-NaF-KF.…”

Proving the Availability of Ni–Fe Anode for Electro-Reduction of Solid V2O3 in Molten Fluoride Salts

“…1 Up to now, the FFC process has been studied intensively for the efficient preparation of numerous metals, novel alloy materials and some functional materials in particular. [2][3][4][5][6][7][8][9][10][11] Several review articles have summarized the fundamentals and developments of the FFC process. [12][13][14][15][16][17][18] From which we can see that in most cases, graphite materials are used as anode with molten chloride salts as supporting electrolytes, e.g., CaCl 2 , LiCl, BaCl 2 , due to their ability to dissolve and transport oxide ion.…”