SMELTING OF IRON OXYSULFIDE MELTS USING SOLID CARBON

Several properties of liquid Fe-S-O at 1 473 K provided the motivation for using iron-oxysulfide melts as smelting medium for iron oxides. Experiments were carried out to determine rates of smelting of Fe-S-O melts by solid carbon at temperatures in the range 1 361-1 525 K. Effect of oxygen concentration, bath agitation rates, and carbon reactivity on the smelting rates were examined. The smelting rates increased with increasing oxygen concentration, bath temperature, and carbon reactivity, but with decreasing bath agitation rates. Microscopic observations and chemical analysis of the melt samples collected after the experiments revealed that sulfur content of the product metal was around the thermodynamic equilibrium value and the metal was not saturated with carbon. It was proved based on a micro-mixing model that the transport of oxygen within the liquid boundary layer adjacent to carbon sample was not a rate limiting process. The reactivity of carbon or carbon gasification reaction at the liquid-solid interface was found to be the most likely rate limiting step.