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 p rocess of stainless steel production, activity of chromium oxide, (CrOX)-Cr -a, and phase relations for the CaO-SiO2-CrOX system have been investigated under moderately reducing conditions, P-O2 = 7.04.10(-6) Pa at 1873 K. Act ivity coefficients of chromium oxides show strong dependencies on X-CaO/X-S iO2, an index of basicity, and chromium content of the slag. Solubility of chromium oxide in the slag system drastically decreases with increasing X-C aO/X-SiO2, which is consistent with increase in activity coefficients of ch romium oxides. The optimal CaO-SiO2-CrOX slag for a practical decarburizati on process has been recommended to be doubly saturated with CrO1.5 and CaCr 2O4, namely X-CaO/X-SiO2 = 1.47 at 1873 K, which may not be significantly a ffected by operating temperatures.