Electroreduction of holmium chloride in the equimolar NaCl–KCl melt

O. V. Chernova, S. V. Zhykovin, D. A. Kondratyev

ABSTRACT

RareCearth metals and their alloys are used in various fields of technology. This is due to their many unique physical and chemical properties. To obtain coatings with rareCearth metals, information is needed on the kinetics of electrode processes with their participation in molten salt media. These problems for rareCearth metals have not been sufficiently studied. In this work we have determined the kinetic parameters (transport coefficients, heterogeneous constants of the charge transfer rate) of cathode reduction of holmium ion in the equimolar NaCl–KCl melt by chronopotentiometry and chronovoltamperometry in temperature range of 1073–1173 and containing 1–10 mas % HoCl₃. The dependences of the kinetic parameters on temperature and the rareCearth metal chloride concentration are presented. A mechanism is proposed for the reduction of the complex in the equimolar NaCl–
KCl melt: НoCl₆^3– = НoCl₄^– + 2Cl^–, НoCl₄^– + e = НoCl₄^2–

KEYWORDS chlorides of rareCearth metals, holmium trichloride, kinetic parameters, chronopotentiometry and chronovoltamperometry

DOI: 10.1134/S0235010619050049