Evaporation of S from Liquid Fe-C-S Alloy

Abstract

Evaporation mechanism of S from liquid Fe-C-S alloys at 1 873 K was proposed by analyzing available experimental data. It has been known that increasing C content in liquid alloy increases activity coefficient of S (f(s)), and it could raise driving force for the evaporation reaction (S) under bar = S(g). However, experimental data of the evaporation of S in the Fe-C-S alloys could not be accounted for only by considering the increases of f(s). In the present study, formation of carbosulfides, CS(g) and CS2(g), was additionally taken into account in order to explain role of C for the accelerated S evaporation. Surface adsorption of S was also taken into account, which retards the evaporation rate of S. An evaporation model equation was formulated. It can be applied to calculate the evaporation rate of S over wider C content (from zero to its saturation to liquid alloy).