B.J. Ingram, Y. Sun, J. Luo, R. Akolkar, J.G. Connell, Q. Liu, Z. Yang
Argonne National Laboratory,
United States
Keywords: Iron, steel production, electrochemical deposition, Fe deposition electrolytes
Summary:
Iron and steel production account for 5-6% of the total manufacturing energy consumption in the United States due, in part, to the high process temperatures required. Fe electrodeposition from acid aqueous electrolytes can provide a novel energy efficient process for producing high purity virgin iron as a copper-free feedstock for augmenting recycled steel scrap. However, electrochemical reduction of iron from mildly acidic aqueous systems presents numerous scientific challenges. For instance, Fe(II) electrolytes can gradually degrade to Fe(III) due to oxidation reactions at the anode during electrodeposition. To design the Fe(II) electrolyte restoration process, the Fe(III) concentration in the Fe(II) electrolytes should be measured in easy and economical ways. We will discuss a simple method of estimating the Fe(III) concentrations by measuring the open circuit potential of the solution, to track the natural oxidation of Fe(II) electrolytes. We observe trends that can be interpreted by the Pourbaix diagram of Fe, and the consistency and reproducibility of pH-potential data suggest the robustness of using the open circuit potential in Fe deposition electrolytes.