Activity of chromium oxide and phase relations for the CaO‐SiO 2 ‐CrO X 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, a CrO X , and phase relations for the CaO‐SiO 2 ‐CrO X system have been investigated under moderately reducing conditions, P O2 = 7.04•10 − 6 Pa at 1873 K. Activity coefficients of chromium oxides show strong dependencies on X CaO / X SiO2 , an index of basicity, and chromium content of the slag. Solubility of chromium oxide in the slag system drastically decreases with increasing X caO / X SiO2 , which is consistent with increase in activity coefficients of chromium oxides. The optimal CaO‐SiO 2 ‐CrO X slag for a practical decarburization process has been recommended to be doubly saturated with CrO 1.5 and CaCr 2 O 4 , namely X CaO/XsiO 2 = 1.47 at 1873 K, which may not be significantly affected by operating temperatures.