Optimal V_(2)O_(3) extraction by sustainable vanadate electrolysis in molten salts

Recently,an environmentally friendly electrolysis process of soluble vanadates is proposed and successfully confirmed for V_(2)O_(3) extraction.In this paper,the solubilities of various vanadates(i.e.NaVO_(3),Na_(4)V_(2)O_(7) and Na_(3)VO_(4))in NaCl molten salt are measured.The dependences of V_(2)O_(3) extraction on vanadate form,anode material and molten salt system are studied.A long-term electrolysis is carried out.The result indicates that the solubilities of all vanadates are high and meet electrolytic requirements.Compared to Na_(4)V_(2)O_(7) and Na_(3)VO_(4),NaVO_(3) exhibits larger current efficiency and lower electricity consumption.By using SnO_(2) anode instead of graphite anode,the current efficiency of NaVO_(3) electrolysis can be increased to 58.1%and carbon pollution is avoided at 700℃.The extraction rate of V_(2)O_(3) reaches 81.3%after long-term electrolysis of 51 h.This work optimizes the electrochemical preparation process of V_(2)O_(3) from various vanadates and contributes to the improvement of current efficiency and extraction rate.