Desulphurization of stainless steel by using CaO-Al2O3 based slags during secondary metallurgy

摘要

The desulphurization behavior of stainless steel by using lime-alumina based slag has been studied on a laboratory scale. The sulphur capacity of the slag was calculated with the aid of FactSage software. Consequently, the equilibrated sulphur distribution was then calculated. The effect of the experimental conditions, such as slag chemistry, temperature and oxygen level of the molten steel on the desulphurization behavior was investigated based on the experimental results and thermodynamic consideration. A kinetic model was developed to predict the evolution of sulphur content in molten steel as a function of time, and a good agreement between experimental data and modeling results was obtained. The sulphur removal rate in molten steel was found to be accelerated with increasing temperature and initial sulphur content in the steel. The desulphurisation capability of optimized lime-alumina based slag was found to be similar as that of lime-fluorspar based slag.