Oxidation Removal of Sn from Carbon Saturated Iron via Ag Phase

Abstract

The oxidation removal of Sn from carbon saturated iron via Ag phase was tried at 1523K. In addition, the thermodynamic data, which are necessary to know the lowering limit of Sn content in carbon saturated iron by this method, were measured.The distribution ratio between carbon saturated iron and Ag, LSn(mass)(=[mass%Sn](in Ag)/[mass%Sn](in Fe–C)) and the activity coefficient of Sn in carbon saturated iron, γ°Sn(in Fe–C), are determined to be 44 and 12.2 at 1523K, respectively. By using these values, the lowering limit of Sn content in carbon saturated iron is calculated to be 1.3×10−8 mass% in oxygen atmosphere (1 atm) at 1523K under the condition that the activity of SnO2 equals to unity. As the experimental results of Sn oxidation removal from carbon saturated iron via Ag phase, the Sn content of carbon saturated iron is actually reduced to less than 0.001 mass% (estimated to be about 0.0001 mass%) from 3 mass%, and it is found that the Sn in molten iron can be removed by the method proposed in the present study.