To realize the removal of Sn from iron scraps by a solidification segregation, we demonstrated the Sn segregation in liquid Fe–C–Sn alloy by unidirectional solidification of utilizing a temperature gradient. The effect of cooling rate on the segregation behavior of Sn is investigated in the present work. The segregation ratio of Sn between solid and liquid is determined based on the experimental data. We found out that the unidirectional solidification of liquid Fe–4.2mass%C–2.0mass%Sn alloy results in the Sn segregation in liquid alloy. The segregation coefficient of Sn is 0.84 for the unidirectional solidification of liquid Fe–4.2mass%C–2.0mass%Sn alloy.