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Influence of Nd2O3 in LiF-NdF3-Nd2O3 melt on carbon anode oxidation was investigated by infra-red spectroscopy and electrochemical techniques to prevent CFX(g) formation during Nd metal production. A gas extractor device was developed to provide fast analysis of the electrochemically produced gas: the carbon anode was only oxidized into CO2(g) until a critical current density was reached. For higher values, CF4(g) and C2F6(g) were also produced. It was associated to diffusion limited current density of NdOF5 4−. To avoid CFX(g) production during the process, the influence of Nd2O3 and temperature on this limiting current density was determined by steady-state voltammetry. [ABSTRACT FROM AUTHOR]

Combining thermodynamic database and electrochemical measurements, CeF3 thermodynamics properties were determined between 1113 K and 1233 K in LiF-CaF2 solution. First, standard potentials of CeF3/Ce were calculated in different reference states: liquid and solid, and infinite dilution. Then activity coefficients of CeF3 were estimated in the different reference states and for different composition scales: molarity, molality and molar fraction. Finally, constants which interconnected the infinite dilution reference state and the solid and liquid reference states were evaluated. [ABSTRACT FROM AUTHOR]