Desulphurisation of Stainless Steel by Using CaO-Al2O3 Based Slags during Secondary Metallurgy

The effect of the slag and steel chemistry on the desulphurisation behaviour of stainless steel by using lime-alumina based slag has been studied on a laboratory scale. The sulphide capacity of the slag and sulphur distribution ratio between slag and steel were calculated with the aid of FactSage software. A kinetic model was developed to predict the evolution of sulphur content in molten steel during the treatment, and a good agreement between experimental data and modelling 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 the optimized lime-alumina based slag was found to be similar as that of lime-fluorspar based slag.