Kinetics of FeS oxidization with steam at elevated temperatures

The kinetics of FeS oxidization with steam at elevated temperature was investigated by measuring the desulphurization rate. The product of FeS oxidization is magnetite (Fe3O4) and the unreacted mineral is transformed to pyrrhotite (Fe1-αS). In the initial stage of oxidation, the Fe is oxidized more preferentially than sulphur. Later a compact product layer of magnetite is formed, then Fe and S are oxidized simultaneously. The experimental data are fitted to a mathematical model of joint control by the chemical reaction at the interface and diffusion of steam through the product layer. The activation energy for the chemical reaction and diffusion are calculated to be 122.0 kJ/mol and 90.2 kJ/mol respectively. Because the product layer becomes more compact in texture and less porous with the increase of steam flowrate, the rate of oxidation exhibits the maximum value when the steam flowrate is 240 ml/s.