Sulfidation behavior of ZnFe2O4 roasted with pyrite: Sulfur inducing and sulfur-oxygen interface exchange mechanism

摘要

The sulfidation roasting behavior was analyzed in detail to reveal the reaction mechanism. Information about the sulfidation reaction, including phase transformation, ionic migration behavior and morphological change, were obtained by XRD, Fe-57 Mossbauer spectroscopy, XPS and SEM analysis. The results showed that the sulfidation of zinc ferrite is a process of sulfur inducing and sulfur-oxygen interface exchange. This process can be divided into six stages: decomposition of FeS2, formation of the oxygen deficient environment, migration of O2- induced by S-2(g), formation of ZnFe2O4-delta, migration of Fe2+ accompanied by the precipitation of ZnO, and the sulfur-oxygen interface exchange reaction. The sulfidation products were zinc blende, wurtzite, magnetite and a fraction of zinc-bearing magnetite. These findings can provide theoretical support for controlling the process during which the recovery of Zn and Fe is achieved through the combined flotation-magnetic separation process. (C) 2016 Elsevier B.V. All rights reserved.