Chemical stability of solutions of niobium V in molten NaCl-KCl at 750 C

Journal Article · Sun Jan 01 00:00:00 EST 1995 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2043859· OSTI ID:6538864

Arurault, L; Poignet, J C ^[1]; Bouteillon, J ^[2]

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1. Centre de Recherche en Electrochimie Minerale et en Genie des Procedes, Saint Martin d'Heres (France)
2. Centre de Recherche en Electrochimie Minerale et en Genie des Procedes, Saint Martin d'Heres (France) Univ. Joseph Fourier, Grenoble (France)

Recently, niobium metal has raised much interest because of its good properties in nuclear technology, electronics, metallurgy, and possibly superconductors. The necessity, for most of these uses, to have highly pure niobium explains why research started in the early sixties for obtaining this metal by molten salt electrolysis as an alternative process to thermal reduction. Solutions of Nb(V), mainly as K[sub 2]NbF[sub 7], in molten NaCl-KCl at 750 C, were studied by potentiometry, linear sweep voltammetry, chemical and X-ray analysis. Voltammograms at tungsten electrodes showed that the use of silica parts in contact with the melt had to be strictly discarded. The variations of the open-circuit potentials of tungsten or vitreous carbon electrodes, recorded during several weeks, showed that the Nb(V) species was not stable and underwent slow reduction to Nb(IV). This hypothesis was reinforced by chemical and X-ray analysis of the frozen melts. Reduction of Nb(V) to Nb(IV) was fast and complete when niobium metal was introduced in the melt.

• OSTI ID: 6538864
• Journal Information: Journal of the Electrochemical Society; (United States), Vol. 142:1; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
NIOBIUM
SYNTHESIS
NIOBIUM COMPOUNDS
ELECTROLYSIS
REDUCTION
ELECTROCHEMISTRY
MEASURING METHODS
MOLTEN SALTS
NIOBIUM FLUORIDES
POTASSIUM CHLORIDES
SODIUM CHLORIDES
TEST FACILITIES
ALKALI METAL COMPOUNDS
CHEMICAL REACTIONS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
ELEMENTS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
LYSIS
METALS
POTASSIUM COMPOUNDS
REFRACTORY METAL COMPOUNDS
SALTS
SODIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
400400* - Electrochemistry
360101 - Metals & Alloys- Preparation & Fabrication