Electrochemical Behavior of Sulfide Ions in Molten Cryolite

摘要

The electrochemical behavior of sulfide ions in molten cryolite (Na sub 3 AlF sub 6 ) has been studied by cyclic voltammetry using graphite electrodes at 1323 K. The oxidation of sulfide ions is found to proceed via a quasi-reversible mechanism, i.e., one in which the current is controlled by both diffusion and charge-transfer kinetics, S exp 2- reversible S + 2e exp - . The transfer coefficient beta and the standard rate constant k/sub s/ are estimated to be 0.5 and 0.0042 cm/s, respectively. The apparent diffusion coefficient for sulfide ions in cryolite at 1323 K is about 3.93 x 10 exp -5 cm exp 2 /s. (ERA citation 08:049593)