The Impact of Iron Oxide Concentration on the Performance of Molten Oxide Electrolytes for the Production of Liquid Iron Metal

Abstract

The effect of iron oxide concentration on the conductive behavior of a molten oxide electrolyte has been investigated at 1823 K using stepped linear scan voltammetry. To maximize the current flow through the electrolyte the ohmic drop in the cell was minimized by shortening the electrode distance. The acquired current was then interpreted by means of an ohmic drop correction, taking into account the conductivity of the alumina-silicate electrolyte and the geometrical form factor of the cell. Via this methodology, a mass transfer limitation in dependence of the iron oxide concentration was identified. This mass transfer limitation vanishes above 7 wt pct of iron oxide where charge transfer starts to be limited solely by electrochemical reaction kinetics. In the analyzed range of concentration, an impact of iron oxide on electronic conduction was not measurable. In addition to these findings, the faradaic yield of the anode half-reaction was determined by the life-measure of O 2 -production. Hereby, a domain of an anodic yield close to 100 pct for various iron oxide concentrations was identified. Based on these findings, suitable conditions for the electrochemical production of liquid iron were determined.

Prospects of Using Pseudobrookite as an Iron-Bearing Mineral for the Alkaline Electrolytic Production of Iron

“…This traditional route of converting iron oxides into metallic iron is responsible for 7 to 9% of global CO 2 direct emissions [1,2]. Apart from molten oxide electrolysis (MOE) [3,4], electrochemical reduction in alkaline media arises as an interesting lean-CO 2 technology for iron production and steelmaking, considering future industrialization [5][6][7][8][9]. The absence of greenhouse gas emissions, the relatively low temperature (~100 • C) used and simultaneous hydrogen and oxygen production due to the water splitting are attractive features of such electrowinning technology.…”