Oxidative Removal of Cu from Carbon-saturated Iron via Ag Phase into B₂O₃ Flux

Abstract

The oxidative removal of Cu from carbon-saturated iron via the Ag phase into B₂O₃ flux was attempted at 1523 K. The Cu content was reduced from 4 to below 0.2 mass%, and Cu in the molten iron could be removed into the B₂O₃ flux by the method proposed in this study. Furthermore, the Cu distribution ratio between the B₂O₃ flux and Ag, L_Cu(flux-Ag) (= [mass% Cu]_{(in flux)}/[mass% Cu]_{(in Ag)}) and the activity coefficients of Cu₂O in the B₂O₃ flux, γ_{Cu2O(in flux)}, owing to the oxygen partial pressure were measured. The greatest value of L_Cu(flux-Ag) was found to be 17 at 0.6 atm of oxygen partial pressure. Using this value, the distribution ratio of Cu between the B₂O₃ flux and carbon-saturated iron is calculated to be 120 at 1523 K. To predict the behavior of solute elements in the Ag phase, a numerical calculation of mass transfer based on Fick's second law is performed and the optimum execution method of oxidative removal of Cu is discussed.