Phase Relationship and Activities of Components in CaO–SiO₂–Cr₂O₃ Ternary System at 1573 K

Abstract

The knowledge of Cr₂O₃ activity in slag is necessary to decarburize chromium-containing special steel while minimizing the oxidation loss of chromium. In the present study, firstly, the phase relationship in the CaO–SiO₂–Cr₂O₃ system was determined at 1573 K. Subsequently, the Cr₂O₃ activities in two- and threephase coexisting slags at 1573 K were measured by equilibrating molten copper with oxide phases under a stream of Ar + H₂ + CO₂ gas mixtures, and the Gibbs energy changes of the formations of CaCr₂O₄ and Ca₃Cr₂Si₃O₁₂ were derived. It was found that the present results were compatible with the phase diagram and the literature data reported at higher temperature than 1573 K.