Production of Iron Alloy by Direct Electrolytic Reduction Using Suspension Electrolysis in an Alkaline Electrolyte

Abstract

Iron alloys were produced by suspension electrolysis in a 50 wt% NaOH–H2O electrolyte at 383 K, and Fe–Cr and Fe–Ni alloys were obtained using a suspension of Fe2O3+Cr2O3 and Fe2O3+Ni(OH)2 particles, respectively. Highly ordered columnar deposits comprising cubic Fe–Cr particles with approximately 5-micrometer-long sides were obtained on a disk cathode with a current efficiency higher than 90% at 100–300 mA･cm–2. In contrast, disordered columnar deposits of Fe–Ni particles with diameters of approximately 1.0 μm were obtained on a disk cathode with a current efficiency of approximately 50% at 200 mA･cm–2. The proposed method affords iron alloys with compositions in the stainless-steel region that depend on the electrolysis conditions, namely, the current density and Fe2O3/Cr2O3 or Fe2O3/Ni(OH)2 content ratio.

Direct Electrodeposition of High-Purity Iron from Fe₂O₃ in Molten Calcium Chloride

“…[7,[12][13][14] Commonly, the low-temperature aqueous solution electrolysis method for the preparation of high-purity iron uses acid/alkaline solvent and soluble ferric chlorides as the electrolyte and iron source, respectively. [15][16][17] In contrast, the molten salt electrolysis strategy is more compatible with raw materials, except for chlorides and oxides, and can even directly use the raw minerals to prepare functional materials, [18] which is undoubtedly conducive to cost reduction. In addition, molten salt as electrolyte can provide a wide electrochemical window to improve the electrolysis efficiency, while the occurrence of hydrogen evolution reaction in the aqueous solution would commonly lower its efficiency.…”