Incorporation of Sulfur in an Optimized Ladle Steelmaking Slag

Abstract

CaO-Al₂O₃-SiO₂=50-42-8 wt% eutectic slags, similar in composition to a secondary steelmaking slag, containing different amounts of CaS, were heated between 1673-1873 K. DTA was performed. Samples were characterized by EMP and XRD. Four main phases were present: CaO·Al₂O₃, 2CaO·Al₂O₃·SiO₂, 2CaO·SiO₂ and 23CaO·14Al₂O₃·CaS or 22CaO·14Al₂O₃·2CaS products of the reaction of CaS with 12CaO·7Al₂O₃ at 1349(±21)K. The sulfur phases crystallized first and the rest of the melt followed the well known CaO-Al₂O₃-SiO₂ phase diagram. For comparison, typical ironmaking and steelmaking slags (CaO-Al₂O₃-SiO₂=48-12-40 wt%) were also utilized to study the incorporation of sulfur in their structure. The resulting phases were all glasses with some non-stoichiometry.