Depolarized SnO2-based gas anodes for electrowinning of silver in molten chlorides

SnO2-based porous anodes were prepared and the behavior of gas bubbles on the porous anodes with different original coarse grain size, immersed in ethanol to simulate molten chlorides, was primarily investigated. SnO2-based porous anodes were used as gas anodes for the electrowinning of silver in CaCl2-NaCl-CaO-AgCl melts at 680°C. Hydrogen was introduced to the anode/electrolyte interface through the gas anode. Carbon was used as the cathode. Obvious depolarization of the anode potential was observed after the introduction of hydrogen comparing with no reducing gas introduced, indicating the involvement of hydrogen in the anode reaction. Metallic silver was deposited on the cathode

Seebeck coefficients of cells with lithium carbonate and gas electrodes

AbstractThe Seebeck coefficient is reported for thermoelectric cells with gas electrodes and a molten electrolyte of one salt, lithium carbonate, at an average temperature of 750°C. We show that the coefficient, which is 0.88mVK−1, can be further increased by adding an inorganic oxide powder to the electrolyte. We interpret the measurements using the theory of irreversible thermodynamics and find that the increase in the Seebeck coefficient is due to a reduction in the transported entropy of the carbonate ion when adding solid particles to the alkali carbonate. Oxides of magnesium, cerium and lithium aluminate lead to a reduction in the transported entropy from 232±12 to around 200±4JK−1mol−1. This is of importance for design of thermoelectric converters