Incorporation of Sulfur in an Optimized Ladle Steelmaking Slag

摘要

CaO-Al_2O_3-SiO_2=50-42-8wt% eutectic slags, similar in composition to a secondary steelmaking slag, containing different amounts of CaS, were heated between 1 673-1 873 K. DTA was performed. Samples were characterized by EMP and XRD. Four main phases were present: CaO·Al_2O_3, 2CaO·Al_2O_3·SiO_2, 2CaO·SiO_2 and 23CaO·14Al_2O_3·CaS or 22CaO·14Al_2O_3·2CaS products of the reaction of CaS with 12CaO·7Al_2O_3 at 1 349(±21)K. The sulfur phases crystallized first and the rest of the melt followed the well known CaO-Al_2O_3-SiO_2 phase diagram. For comparison, typical ironmaking and steelmaking slags (CaO-Al_2O_3-SiO_2=48-1 2-40 wt%) were also utilized to study the incorporation of sulfur in their structure. The resulting phases were all glasses with some non-stoichiometry.