Electrodeposition of Iron in Aqueous Alkaline Solution: An Alternative to Carbothermic Reduction

摘要

In our previous studies, we have demonstrated that the electrodeposition of iron from iron oxide particles suspended in concentrated sodium hydroxide mixture could be an efficient and cost-effective process for iron production with significantly reduced carbon dioxide emissions. Electrodeposition of compact metal deposits is of significant technical importance. In this paper, we present the different microstructures of iron deposited on rotating graphite substrate under different experimental conditions. These textures can be classified as three types: powdery deposit with a needle shape; compact deposit with a columnar structure of flattened layer-by-layer crystal growth; fairly dense deposit with compact pyramid layers. Processes involved in the electrochemical formation of the three dimensional bulk deposits, i.e., the mass transfer and electro-reduction of the iron oxide particles to iron metal atoms, and the subsequent nucleation and crystal growth on the graphite-cathode surface were discussed with respect to their influences on the microstructure of the deposited iron metal.