Electrochemical characterization of fine-grained blast furnace sludge after acid leaching using carbon paste electrode

The paper deals with the study of electrochemical properties of blast furnace sludge after acid leaching (BFSL) using modified carbon paste electrodes (CPEs) in acidic (1 M HCl) and alkaline (1 M NaOH) electrolyte. A polyamide holder with exchangeable tips was developed. The effect of their geometric parameters on the electrochemical response was monitored. The electrochemical characterization was performed by cyclic voltammetry (CV) at different scan rates. The hematite and magnetite served as comparative model modifiers. The identification of reaction products was performed using the RTG diffraction and SEM/EDX analyses. It was found that reduction reactions are suppressed at acidic pH. On the contrary, in an alkaline media, a significant peak corresponding to the electrode reduction of iron oxides based on the scheme Fe³⁺?→?Fe²⁺?→?Fe⁰ was identified in the BFSL reduction region. XRD and SEM analyses of the active surface of modified CPE showed the formation of nanostructured Fe. The results provide direction for the further use of BFSL.