Recycling the industrial waste ZnFe2O4 from hot-dip galvanization sludge

Abstract

In this study, the goal was to find lower temperature for separating the Zn and Fe content of ZnFe2O4 by sulfation reaction than previously achieved, and to study the various reactions steps of sulfation. Hence, the reaction of ZnFe2O4 with Mohr's salt containing iron(II), i.e. (NH4)2Fe(SO4)2•6H2O, and ammonium iron alum containing Fe(III), i.e. NH4Fe(SO4)2•12H2O was studied. At first the thermal decomposition of precursor salts in air was studied by TG/DTA-MS to find the proper temperature for sulfation. Then ZnFe2SO4:precursor salt mixtures with ratios 1:2 and 1:5 were prepared and annealed at 400, 425, 450 °C. The solubility of the products obtained at different annealing temperatures in water (e.g. ZnSO4, FeSO4, Fe2(SO4)3) and in HCl (Fe2O3, ZnO, Fex(OH)ySO4, Znv(OH)wSO4 basic sulfates) was studied. The morphology and structure of the starting materials was investigated by SEM, XRD and FTIR, the crystalline phases after each annealing and washing steps were studied by XRD. The Fe in the starting materials and the products obtained at 425 °C was measured by Mössbauer. Based on the obtained results,

Synthesis of Fe3O4/ZnO from Zinc Dross Waste as an Active Material for Dye-Sensitized Solar Cells

“…Interestingly, the galvanizing industry produces a huge amount of Zn waste from galvanization process which may harm the environment if it is not treated properly. Moreover, galvanization is the most common method to protect the steel from corrosion event which implies the importance of this process in steelmaking industry [10][11][12]. Among other waste in the galvanizing process (zinc ash, zinc flue dust, and brass smelting), zinc dross has the highest zinc content, which can reach up to 96% Zn (and 4% Fe), thus has the highest change to be purified in order to recover the zinc content [13,14].…”

Composition and Leaching Toxicity of Hydrochloric Acid Pickling Sludge Generated from the Hot-Dip Galvanized Steel Industry

“…Commonly, the yield of SHPS is approximately 30–50 kg/ton of steel. − Regarding SHPS, to treat its toxicity, recover its resources, or assess its environmental risks, Fekete et al studied the separation of zinc and iron from SHPS by sulfation. Arsenovic et al studied the removal of toxic metals from SHPS by fixing it in a brick structure.…”

Comprehensive Study on the Mechanism of Sulfating Roasting of Zinc Plant Residue with Iron Sulfates

“…Separately, methods should be noted to obtain water-soluble zinc sulfate by the roasting with elemental sulfur in air [ 33 ], sulfuric acid [ 34 , 35 , 36 ], ammonium sulfate [ 37 , 38 ], as well as using blowing of mixture of sulfur dioxide and air [ 39 , 40 ]. Sulfation method has several advantages compared with other methods.…”