The Electrolytic Reduction of MoO₃ in CaCl₂-NaCl Molten Salt

Abstract

Electro-deoxidation reduction technology is a very attractive method used to treat oxides in the metallurgical industry. Here, cyclic voltammetry, square wave voltammetry, and open circuit chronopotentiogram were applied to study the electrochemical behavior of MoO3 cathode in the CaCl2-NaCl melt at 873 K. Through the electrolytic reduction of MoO3 at different potentials (-1.15 V, -1.45 V, and -1.75 V, vs Ag/AgCl) and X-ray diffraction analysis, MoO3 was found to be transformed into several intermediate compounds (CaMoO4, MoO2, and Na1.4Mo2O4) and finally reduced to metallic Mo. When the electrolysis time was increased from 3 to 18.5 h and the employed potential was reduced from -1.75 to -2.30 V (vs Ag/AgCl), the intermediate compounds could be completely reduced to metallic Mo, and the reduction ratio of MoO3 was calculated to be 93.7%.

Electrolytic Reduction of U3O8 and U3O8-MoO3 in CaCl2-NaCl Molten Salt

“…According to the results obtained in Fig. 8 and our previous work of MoO 3 , 23 it could be confirmed that the reduction peak G is MoO 3 → MoO 2 and peak F is MoO 3 → Na 1.4 Mo 2 O 4 . The cathodic peak E corresponded to the reduction of some intermediate products (CaMoO 4 , MoO 2 and Na 1.4 Mo 2 O 4 ) to the metallic Mo.…”

“…In our previous studies, cathodic peaks G, F and E should correspond to the generation of MoO 2 , Na 1.4 Mo 2 O 4 and metal Mo, respectively, while the anode peaks F′ at −1.05 V and G′ at −0.33 V (vs Ag/AgCl) belonged to the corresponding oxidation reactions, respectively. 23 Figure 8 showed the XRD patterns of U 3 O 8 and MoO 3 mixture before and after sintering. The U 3 O 8 -MoO 3 tablet was sintered at 923 K for 10 h. Two phases of U 3 O 8 and MoO 3 can be observed in the XRD pattern before sintering.…”

Electrolytic Reduction of ZnO in the CaCl2-NaCl Molten Salt

“…1,4,14 Therefore, the research on developing and optimizing direct reduction of metal oxides technology for metal preparation is essential. At present, many metal oxides, such as TiO 2 , 11,15 ZrO 2 , 16 HfO 2 , 17 Nb 2 O 5 , 18 Ta 2 O 5 , 4 Cr 2 O 3 , 19 MoO 3 , 20 and NiO, 21 etc., have been used as raw materials by this method. Meanwhile, various molten salt systems, such as LiCl, LiCl-Li 2 O, CaCl 2 , CaCl 2 -NaCl, and LiCl-KCl-CaCl 2 , have been used as the electrolytes for the electrolytic reduction process.…”