Treatment of Simulated Steel Pickling Waste Liquor by Electrochemical Synthesis of Fe3O4

Due to the serious pollution and great harm of steel pickling waste liquor, the treatment of the waste liquor with high concentration of iron ion has been a problem in a lot of countries around the world. A simple electrochemical method is proposed for recovering iron from steel pickling waste liquor with graphite plates as electrodes. This study investigated the effects of reaction parameters on the concentration of residual total iron (TFe) in steel pickling waste liquor, including initial pH, reaction temperature, electrode distance, current density, and electrolytic time. Under the optimal reaction condition, the removal efficiency of TFe was 99.98%. The obtained precipitates were measured by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. It was found that the precipitates were high purity of Fe3O4 with small amount of γ-Fe2O3. This method will provide an effective and potential solution for resource recycling of steel pickling waste liquor.