Abstract:The Sn could be effectively removed from Sn-bearing iron concentrates through its reduction and sulfurization under H2S atmosphere. Based on the results of thermodynamic analysis, the phase transformation of Sn and Fe and the mechanism of separating Sn in the Sn-bearing iron concentrates are researched. The results show that the H2S(g) will be translated into S2(g) and H2(g) through self-decomposition. Formation S2(g) will preferentially reduce and sulfurize Fe3O4 to Fe7S8, while H2(g) reduces SnO2 to Sn(l). The addition of CO can promote the reduction and sulfidation of SnO2 in the roasting system. Under the optimum experimental parameters of the mixed gases (60vol%CO(g) + 40vol%H2S(g)) flow rate of 70 ml/min, roasting temperature of 1000 ℃, roasting time of 20 min and particle size of 200 meshes, the Sn volatilization ratio reached 95.34%.