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Study On Selective Acid Leaching Process Of Zinc Calcine Flash Reduction Roasting Production

Posted on:2014-10-12Degree:MasterType:Thesis
Country:ChinaCandidate:T Z ChenFull Text:PDF
GTID:2251330425470746Subject:Metallurgical engineering
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Abstract:Sphalerite is the main raw material for zinc-smelting, armatite accounted for large proportion, zinc ferrite (ZnOFe203) is inevitably produced in the process of roasting zinc sulfide and its chemical properties is stable, hard to dissovled in diluted acid. Much iron is leached from high-iron zinc calcine in the zinc leaching process under the condition of high temperature and high acid, which overburdening subsequent removal iron process. This process will produce a large amount of rich-iron waste residue, which contained many kinds of valuable elements. These residue could cause serious environmental pollution and resource waste.The study was supported by the national high technology research and development program "863" key project (2011AA061001B eneficiation-metallurgy joint clean metallurgical technology), based on the problems and deficiencies existing in the zinc-smelting process, combined with the current society developing needs of resource-conservation and environment-friendly model. Zinc calcine, which was provided by a zinc-smelting factory, and its flash reduction roasting products were used as the research object in this study. Selective leaching zinc but iron was remained in the residue as the form of desired compound by using selective acid leaching process for realizing zinc-iron separation.Firstly, we had explored that the acidity and temperature was the two important factors for reduction zinc calcine leaching, then a series of single factor leaching experiments and orthogonal experiment of reduction zinc calcine had been proceed based on the analysis of material properties, the optimal process parameters for selective acid leaching of flash reduction zinc calcine was determined. The experimental results showed that the leaching rate of zinc and iron of optimal flash reduction zinc calcine was91.38%,17.64%respectively under the conditions of leaching optimal process, the selective leaching of zinc was basically achieved. Under the same leaching conditions, the leaching rate of zinc increased more than9%after flash reduction roasting of zinc calcine, iron content of the leaching residue increased nearly10%; Zinc calcine leaching experiments, reduction zinc calcine leaching exploratory experiments have been proceed, combined with analysis of orthogonal experiment data, the results have consistently shown that initial acidity and liquid-solid ratio was the two most important factors influencing zinc and iron leaching index; The influence of flash reduction roasting conditions on the leaching of zinc and iron was studied, the study showed that zinc calcine flash reduction roasting production under the conditions of CO%was4%, the furnace chamber temperature below900℃were good for zinc-iron separation, the influence of reaction tower temperature on the leaching effect was not remarked. The formation of the desired magnetic compound Fe3O4by the efficient decomposition of ZnO·Fe2O3in zinc calcine on the process of flash reduction roasting was essential to realize the effective zinc-iron separation, which improved the leaching rate of zinc meanwhile hindered the extraction of iron. The process mineralogy characteristics such as phase composition, morphology of zinc calcine and its related products were analysed by using XRD, SEM, EDX etc. some kinds of detection analytical methods. The results showed that the leaching rate of the zinc as well as the filtering performance of the residue was improved due to the porous structure of reduction zinc calcine, which help that the leaching reaction was done rapidly at near room temperature. The number of figures28, the number of tables21, the number of references129.
Keywords/Search Tags:flash reduction zinc calcine, zinc ferrite, selective leaching, zinc-iron separation
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