Voltaic Cells in Fused Salts: Part I. The Silver – Silver Chloride, Cobalt – Cobaltous Chloride System

Abstract

A reversible silver − silver chloride reference electrode for use in melts at high temperatures has been developed. It was found that the solution of silver chloride in an equimolar mixture of KCl–NaCl melt is ideal for the range of concentrations studied, i.e. 1.0 × 10−3 to 6.0 × 10−2 mole fraction of AgCl.The electromotive force of the voltaic cell[Formula: see text]in which the half-cell to the right contains the above-mentioned reference electrode, was measured as a function of CoCl2 concentration. The applicability of the Nernst equation to this system was established. Deviation from ideality was observed in the case of the solution of CoCl2 in the melt solvent, and this was attributed to the formation of a complex. The dissociation constant of this complex was calculated as 4.50 × 10−2 at 710 °C.The effect of temperature on the electromotive force of this cell was also measured, and the heat of the cell reaction in the presence of solvent (Co + 2AgCl → CoCl2 + 2Ag) was calculated from the data as 22.8 ± 1.3 kcal.The thermodynamic significance of the standard electrode potential of the Co–Ag voltaic cell, derived experimentally as 0.324 volt, is discussed briefly.

Electrode Potentials of Thorium Tetrachloride in Alkali Chloride Melts

“…A/Ieasurements of the "apparent standard" potentials of several inetal-inetal chloride systems in dilute solutions in fused alkali chlorides have been reported in previous investigations (1,2,3,13). Such measurements provide data on activities, help determine the equilibrium constants of chemical reactions in fused salts, and give some of the necessary information for the electrolytic recovery of metals by fused salt electrolysis.…”

Preparation of Titanium Deposit in Chloride Melts

“…[13,14] The electrochemistry of titanium dichloride in molten salts and the deposition of metallic titanium from titanium chlorides have been the subject of many investigations. [15][16][17][18][19][20][21][22][23][24][25] Therefore, as part of our USTB process, in which titanium ion from the anode dissolution of titanium oxycarbide in molten salts will electrodeposit in the cathode, the electrokinetic parameters of cathodic deposition such as current density, and initial titanium ion concentration could affect the morphology and purity of titanium deposit.…”

Thermodynamic evaluation and optimization of the (NaCl + KCl + MgCl2+ CaCl2+ ZnCl2) system

“…Some data points derived from the e.m.f. measurements of Flengas and Ingraham [63] are also shown; the method used to derive them is described in detail below. …”

“…The (NaCl + KCl + NiCl 2 ) [9] and (NaCl + KCl + PbCl 2 ) (unpublished work) ternary liquids have been optimized previously, and the activity a MCl 2 of MCl 2 (M = Pb or Ni) in a (NaCl + KCl) equimolar melt was calculated at the compositions and temperatures studied by Flengas and Ingraham [63]. E M was measured by the authors; x AgCl was reported by the authors; E o M was calculated (using standard thermodynamic data) for the reactions Pb(l) + 2AgCl(l) = PbCl 2 (l) + 2Ag(s) (at T = 955 K) and Ni(s) + 2AgCl(l) = NiCl 2 (s) + 2Ag(s) (at T = 978 K), respectively.…”