The possibility of obtaining silumins in KF-AlF3 melts via SiO2 additions at a temperature of 720°C is investigated. Silumins with high silicon contents (up to 37 wt%) can be obtained in KF-AlF3-SiO2 melts via the electrochemical co-deposition of aluminum and silicon on a graphite cathode in both galvanostatic and potentiostatic modes. Electrode processes are studied with cyclic voltammetry. It is shown that the peak of silicon cathode deposition with the addition of SiO2 is fixed at a potential of about −0.8 V (in relation to the CO/CO2 reference electrode). The expansion of the silicon allocation potential area from a value of −0.5 V with increasing concentration of SiO2 in the melt indicates the complex ionic structure of the melt.

The mechanism for the electrode process that occurs on a molybdenum substrate in LiCl-KCl-PbCl 2 and LiCl-KCl-PbCl 2 -PbO melts depending on the concentration of PbO was investigated over the temperature range of 723-823 K using stationary polarization curves and voltammetry techniques. An increase in the concentration of PbO was found to decrease the diffusion-limiting current density for the recovery of lead, which was identified by the appearance of an additional peak in the voltammograms; it can be explained by a decrease in the concentration of Pb 2+ ions decrease due to the formation of Pb 2 O 2+ complex ions in the electrolyte. The evaluation of the equilibrium constant K E and the rate constant of the reaction suggests that this reaction is strongly shifted toward the formation of the Pb 2 O 2+ complex ions. A theoretical polarization curve for the diffusion kinetics was calculated.Investigating the kinetics of electrode processes allows one to determine the kinetic parameters of reactions, to calculate the activation energies of these reactions and to establish the limiting stages of electrode processes. 1 Additionally, data related to the mechanism of the electrode processes is valuable for developing the scientific basis for electrochemical technologies that meet the current ecological and energy saving requirements.In the literature, considerable attention is focused on the electrorecovery of lead from molten salts. The authors 2,3 reported that the electro recovery of Pb 2+ ions from a LiCl-KCl melt is a diffusioncontrolled, single-stage reaction.Haaberg et al. 4 investigated the lead electrodeposition process in LiCl-KCl melts and in pure PbCl 2 and determined that the migration of Pb 2+ ions controls the rate of the cathode process in the pure PbCl 2 melt at temperatures from 823 to 858 K. A diffusion regime of the process was observed in the LiCl-KCl melt; the diffusion coefficient for the Pb 2+ ions was equal to 2 · 10 −5 sm 2 /s. The cathode behavior of lead ions on a molybdenum substrate in LiCl-KCl-PbCl 2 and LiCl-KCl-PbCl 2 -MgCl 2 melts was studied using voltammetry and chronopotentiometry techniques in later works. 5 The extraction of lithium from the initially deposited lead was found to result in the formation of a Li-Pb alloy in LiCl-KCl-PbCl 2 and LiPb-Mg melts with the addition of MgCl 2 . The diffusion coefficient of Pb 2+ ions was determined using various techniques, and its value was found to be 2.26 · 10 −5 sm 2 /s. In a number of studies, there are considerable differences regarding the mechanism of the cathode process. Therefore, Strenberg et al. 6 established a two-stage mechanism for the recovery of Pb 2+ ions through the stage of the formation of monovalent Pb + ions.These works were primarily performed during the second half of the XX th century and were related to dilute solutions of lead in alkali metal chlorides, free of oxide ions. There is no information available regarding the mechanisms of electrode processes in oxide-chloride melts. The structures and compositions of ...

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The electromotive forces of the electrochemical system (GC)Pb|(1–N)·KCl–PbCl2+N·PbO|ZrO2(Y2O3)|O2(Pt) in the mole fraction range of PbO 0.0016 to 0.0732 were measured at temperatures of (776, 821, and 874) K. The activities, the activity coefficients, and the basic thermodynamic functions of lead(II) oxide for dilute solutions were calculated from the experimental EMF values.

Effects of the KF-NaF-AlF 3 melt composition, ZrO 2 concentration and aluminothermic synthesis parameters on the conversion rate of zirconium to aluminum were investigated. The kinetics of zirconium electroreduction on glassy-carbon obtained from KF-AlF 3 -ZrO 2 melts at a temperature of 750 • C was studied via the cyclic voltammetry method. Parameters of the electrolysis of KF-NaF-AlF 3 -ZrO 2 melts were derived on the basis of obtained results, and the theoretical possibility for the electrolytic production of Al-Zr master alloys (having up to 15 wt% zirconium content) was demonstrated.