Mass Transport Phenomena in the Molten Sulfur‐Sodium Polysulfide System

Abstract

The exchange rate for mass transfer of sulfur across the sulfur‐sulfur saturated sodium pentasulfide interface was investigated by S‐35 tracer studies and found to be at 300°C. The self‐diffusion coefficients of sulfur in and as determined by the capillary method using S‐35 labeling were , respectively, at 300°C. The diffusion coefficient of the electroactive species in was determined by chronopotentiometry at a rotating disk electrode. Its value is at 300°C. Approximate values of the activation energy of diffusion and in are given. A first attempt is made, in terms of a mechanistic model of the mass‐transfer processes, to explain the different data obtained for from tracer and electrochemical experiments, respectively.