Duro was particularly designed for rapid slag formation and efficient refining in secondary metallurgy. In high quality iron and steel production, very low sulphur content is required. This low sulfur content results in obtaining high quality iron and steel. Flux used for desulphurization includes CaO and CaF2 phases. Due to inadequate reactive phases, a slow and inadequate amount of desulphurization slag forms. DURO offers not only excellent chemistry with optimum oxide composition by carrying out the desulphurization in a limited time interval, but also maximum reactive phase.