Reduction and Sulfurization Behavior of Tin Phases in Tin-bearing Iron Concentrates with Sulfates in Sulfur-bearing Stone Coal

Abstract

The tin could be effectively removed from tin-bearing iron concentrates through roasted with sulfur-bearing stone coal reported in previous researches, and the Sn volatilization ratio was obviously influenced by the amount of sulfur-bearing stone coal used. The reactivity of sulfate (FeSO₄) in sulfur-bearing stone coal on the reduction and sulfurization behavior of cassiterite (SnO₂) in tin-bearing iron concentrates was studied in this paper. The thermodynamic analysis and experimental results showed that Fe–Sn spinel was formed with the increase of FeSO₄ amount during the roasting process, and it resulted in the tin volatilization ratio being relatively low (a maximum of 61.87%). Furthmore, the EPMA analysis indicated that the Fe–Sn spinel was mostly concentrated in the upper layer of the roasted residues, and these tin could be further removed and recovered by a physical separation process.