Determination of coordination form of tungsten ion in molten alkali chloride by electrochemical method

Abstract

The results of the coordination form of low-concentration ions in molten salt have great reference significance for exploring the electrolysis reaction mechanism. Given the low concentration of tungsten ions after the electrochemical dissolution of tungsten carbide, this can be difficult to judge the coordination form of tungsten ions through spectral characterization. This paper will struggle to tackle the problem by comparing the electrochemical behaviors of tungsten ions from the electrochemical dissolution of tungsten carbide and NaCl–KCl–2 wt% Na2WO4 melt. The electrochemical method had been investigated as a mean to understand the fundamental thermodynamic and mass transport properties of tungsten ions. The apparent standard potentials of oxidation and reduction couple at several temperatures were calculated by using a proposed new method. The diffusion coefficients of tungsten ions were determined. It can be concluded that the tungsten ions in the molten salt after tungsten carbide electrolysis were simple ions without coordinating anions by comparing the dynamics and thermodynamic calculation results of the two systems. The developed simulation boxes can serve as a verification for further theoretical investigations of the coordination form of tungsten ion groups at molecular scale. The results of this work provide necessary knowledge for the development methods to determine the dynamics and thermodynamic properties and coordination forms of metal ions.