Abstract
Direct electrochemical reduction of iron ore in concentrated NaOH electrolyte has been proposed as a potential route to substantially reducing the global steel industry’s CO2 emissions. Here, we report the solid-state electro-reduction of sintered pellets formed from titanomagnetite ironsand. This commercial iron ore contains ∼4 wt.% Ti which is directly incorporated within the magnetite lattice. At 110 °C, these pellets are electrochemically reduced and exhibit a well-defined reaction front which moves into the pellet as the reaction progresses. The electro-reduction process selectively produces iron metal, whilst the Ti content is not reduced. Instead, Ti becomes enriched in segregated oxide inclusions, which are subsequently transformed to a sodium iron titanate phase through taking up Na+ from the electrolyte. These inclusions adopt an elongated shape and appear to exhibit locally preferential alignment. This suggests that they may nucleate from the microscopic titanohematite lamellae which naturally occur within the original ironsand particles. The expulsion of contaminant Ti-oxides from the final reduced metal matrix has implications for the potential to development of an industrial electrochemical iron-making process utilising titanomagnetite ore.
Highlights
Iron and steelmaking is responsible for 7% of total global CO2 emissions [1], making it the second largest industrial source
This paper describes an experimental study into the feasibility of alkaline electroreduction of TTM ironsand, and the fate of titanium species during this process
Reduction starts at the surface and proceeds inwards, forming a porous metallic layer with a well-defined reaction front
Summary
We report the author(s) and the title of solid-state electro-reduction of sintered pellets formed from titanomagnetite ironsand. This the work, journal citation and DOI. Ti becomes enriched in segregated oxide inclusions, which are subsequently transformed to a sodium iron titanate phase through taking up Na+ from the electrolyte. These inclusions adopt an elongated shape and appear to exhibit locally preferential alignment. Ti-oxides from the final reduced metal matrix has implications for the potential to development of an industrial electrochemical iron-making process utilising titanomagnetite ore
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