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Title: Studies of the electrochemistry of niobium(V) in sodium chloroaluminate and fluorochloroaluminate melts

Miscellaneous ·
OSTI ID:7178108

Methods for the removal of oxide from LiF:NaF:KF (46.5:11.5:42.0 mole %) and sodium chloroaluminate molten salts were investigated. Raman spectroscopy of LiF:NaF:KF melts containing K[sub 2]TaF[sub 7] was utilized to determine the oxide level of the melts after several different purification techniques had been employed. In the case of sodium chloroaluminate, it was found that both phosgene (COCl[sub 2]) and carbon tetrachloride (CCl[sub 4]) were efficient oxide removal agents. The electrochemistry of Nb(V) in sodium chloroaluminate at 178[degrees]C was examined using various voltammetric techniques. It was found that reports of various workers in this system were erroneous due to the fact that these workers did not realize their melts were contaminated with oxide. The Nb(V) electrochemical behavior was re-investigated using melts that had been treated with either phosgene or carbon tetrachloride, and which were therefore essentially oxide-free. It was determined that Nb(V) first undergoes a one-electron reduction to Nb(IV), followed by further reduction of Nb(IV) to lower-oxidation state cluster species. Studies of the electrochemical behavior of Nb(V) were conducted in sodium chloroaluminate and fluorochloroaluminate melts, in the temperature range 160 to 500[degrees]C. While temperature had a marked effect on the electrochemistry of Nb(V), the addition of fluoride appeared to have little effect. Attempts to deposit niobium metal from these melts were somewhat successful.

Research Organization:
Tennessee Univ., Knoxville, TN (United States)
OSTI ID:
7178108
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English