SOLID PHASE SULPHATIZING OF ZINC FERRITE SPINEL WITH IRON SULPHATES AS AN ENVIRONMENTAL FRIENDLY WAY FOR RECOVERING ZINC

Anurag Saini, László Kótai, István E. Sajó, Imre Miklós Szilágyi, Károly Lázár, Zoltán May, Péter Fazekas, István Gács, Vinita Sharma, Kalyan K Banerji

Abstract


The scarcely reactive zinc ferrite can be decomposed in solid phase to water-soluble ZnSO4 and water-insoluble Fe2O3polymorphs byexcess of solid iron(II or III) sulphates at 650°C in 4 h. Since SO3 forms in situ from the Fe2(SO4)3 as well as anhydrous Fe2(SO4)3 formsin the thermal oxidation of iron(II) sulphate, therefore the gaseous SO3 is the active sulphatization agent in the reaction of thehydrated iron(II and III) sulphates and the zinc ferrite. The sulphatization process were monitored by XRD, TG/DTA-MS, Mössbauer,Raman and IR-spectroscopy and the changes in reaction’s heat and Gibbs energy are reported. The Fe2O3 polymorphs formed is worthprocessing into iron(III) sulphate by sulphuric acid. Since the Fe2(SO4)3formed in this way can be recycled to the sulphatization process,the only reagent consumed is the sulphuric acid. Therefore, these selective sulphatization reactions can be taken as “iron salts mediated”decompositions of zinc ferrite into ZnSO4 and Fe2O3 by sulphuric acid.


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DOI: http://dx.doi.org/10.17628/ecb.2012.1.7-13

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