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Separation And Recovery Of Iron From High Iron Bearing Zinc Calcine By Magnetic Roasting

Posted on:2014-01-27Degree:MasterType:Thesis
Country:ChinaCandidate:N PengFull Text:PDF
GTID:2251330425971052Subject:Environmental Science and Engineering
Abstract/Summary:PDF Full Text Request
As the use of high iron bearing zinc calcine is becoming increasingly wide, the treatment of zinc ferrite which produced in the desulphurization roasting of high iron bearing zinc blende has turned to be a heavily problem. It could cause the waste of zinc and iron because the zinc ferrite is insoluble in at normal leaching conditions. Meanwhile, the zinc leaching residue has high environmental risk as the high content of heavy metals. This paper focused on the treatment of high iron bearing zinc calcine, in this process, zinc ferrite in zinc calcine was decomposed into magnetite and zinc oxide by magnetic roasting; and then the magnetite was recovered by magnetic separation and zinc-rich tailing of magnetic separation was reused in traditional zinc smelting process.The Thermal Gravity Analysis-Differential thermal gravity (TG-DTG), X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and X-Ray Fluorescence (XRF) were applied in the characterization of physical and chemical properties of zinc calcine. The HSC and Factsage were used for the theoretical analysis of zinc calcine’s magnetic roasting process; it shows that, comparing with using carbon as reduction agent, CO could avoid the over-reduction of iron oxide, and maintaining suitable roasting temperature and atmosphere are key factors for the magnetization of zinc calcine. It could be seen from the characterization of roasted product that the particle size increases and the surface of particle size becomes denser after roasting, and the magnetization intensity of roasted product enhances as the generation of magnetite. The optimum technological conditions are as follow:roasting temperature750℃, roasting duration60min, volumn of CO6-8%, CO2/(CO+CO2)70%-80%; magnetic intensity1160G, magnetic separation duration20min, leaching acidity90g/L, leaching time20min. The recovery and grade of iron in concentration could reach about82%and51%under optimum technological conditions, while the zinc content in concentration is as high as14%, which needs to be further reduced. Based on these achievements, the multi-stage magnetic separation process was designed and not only the iron could be separated from zinc but also the Sn, S, Cd could be enriched in this process.
Keywords/Search Tags:zinc calcine, zinc ferrite, magnetic roasting, magneticseparation
PDF Full Text Request
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