Activity of chromium oxide and phase relations for the CaO‐SiO2‐CrOX system at 1873 K under moderately reducing conditions

In order to optimize the slag composition operated in the decarburization process of stainless steel production, activity of chromium oxide, aCrOX, and phase relations for the CaO‐SiO2‐CrOX system have been investigated under moderately reducing conditions, PO2 = 7.04•10− 6Pa at 1873 K. Activity coefficients of chromium oxides show strong dependencies on XCaO/XSiO2, an index of basicity, and chromium content of the slag. Solubility of chromium oxide in the slag system drastically decreases with increasing XcaO/XSiO2, which is consistent with increase in activity coefficients of chromium oxides. The optimal CaO‐SiO2‐CrOX slag for a practical decarburization process has been recommended to be doubly saturated with CrO1.5 and CaCr2O4, namely XCaO/XsiO2 = 1.47 at 1873 K, which may not be significantly affected by operating temperatures.