Recovery of iron as a form of ferrous acetate precipitates from low-grade magnetite ore

This paper describes the recovery process of iron as a form of ferrous acetate from low-grade magnetite ore (Shinyemi Mine, Gangwon province, Korea). The magnetically separated magnetite powder was dissolved in aqueous oxalic acid solution. The dissolution fraction of magnetite concentrates was measured as a function of initial pH, reaction temperature and oxalic acid concentration. Optimum conditions for dissolution of magnetite ore were the temperature higher than 90 °C, pH 1 and oxalic acid concentration 0.5 M. Addition of aqueous H2O2 solution oxidized ferrous ion of iron-containing solution. And then, at pH 4, ferric hydroxide was precipitated from iron-containing solution by the addition of NaOH aqueous solution. Ferrous acetate was prepared from the reaction between ferric hydroxide and acetic acid/acetic anhydride mixture and quantitatively characterized by ICP-AES, XRD, SEM, FT-IR and XPS. Purity of ferrous acetate was found to be 91.88% with other impure elements such as Na, Ca, K, Mg and Al by ICP-AES and XPS analysis. XRD and SEM analysis showed that as-prepared ferrous acetate in the present experiments was in low crystalline state. FT-IR spectra confirmed the presence of free acetate ions and monoacetato bidentate structure in as-prepared ferrous acetate.